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Sample records for bleached kraft pulp

  1. REPLACEMENT OF SOFTWOOD KRAFT PULP WITH ECF-BLEACHED BAMBOO KRAFT PULP IN FINE PAPER

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    Guanglei Zhao

    2010-06-01

    Full Text Available Non-wood fibers such as bamboo and wheat straw have been playing important roles in the pulp and paper industry in China. In this study an ECF-bleached bamboo kraft pulp was compared with a bleached softwood kraft pulp (NBSK as the reinforcement pulp in fine paper production. Areas that were examined include the refining of pure fibers, influence of bamboo on dewatering, retention, and sizing. The influence of bamboo kraft pulp as a part of a furnish replacing NBSK was compared as well. Results show that fiber shortening was more prominent with bamboo when refined. This resulted in a higher amount of fines, and addition wet-end chemicals may be required to compensate. Handsheets with bamboo as a reinforcement fiber showed similar mechanical and optical properties to handsheets containing NBSK.

  2. Multivariate Analysis of Hemicelluloses in Bleached Kraft Pulp Using Infrared Spectroscopy.

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    Chen, Zhiwen; Hu, Thomas Q; Jang, Ho Fan; Grant, Edward

    2016-12-01

    The hemicellulose composition of a pulp significantly affects its chemical and physical properties and thus represents an important process control variable. However, complicated steps of sample preparation make standard methods for the carbohydrate analysis of pulp samples, such as high performance liquid chromatography (HPLC), expensive and time-consuming. In contrast, pulp analysis by attenuated total internal reflection Fourier transform infrared spectroscopy (ATR FT-IR) requires little sample preparation. Here we show that ATR FT-IR with discrete wavelet transform (DWT) and standard normal variate (SNV) spectral preprocessing offers a convenient means for the qualitative and quantitative analysis of hemicelluloses in bleached kraft pulp and alkaline treated kraft pulp. The pulp samples investigated include bleached softwood kraft pulps, bleached hardwood kraft pulps, and their mixtures, as obtained from Canadian industry mills or blended in a lab, and bleached kraft pulp samples treated with 0-6% NaOH solutions. In the principal component analysis (PCA) of these spectra, we find the potential both to differentiate all pulps on the basis of hemicellulose compositions and to distinguish bleached hardwood pulps by species. Partial least squares (PLS) multivariate analysis gives a 0.442 wt% root mean square errors of prediction (RMSEP) for the prediction of xylan content and 0.233 wt% RMSEP for the prediction of mannan content. These data all support the idea that ATR FT-IR has a great potential to rapidly and accurately predict the content of xylan and mannan for bleached kraft pulps (softwood, hardwood, and their mixtures) in industry. However, the prediction of xylan and mannan concentrations presented a difficulty for pulp samples with modified cellulose crystalline structure. © The Author(s) 2016.

  3. Removal of COD and color loads in bleached kraft pulp effluents by bottom ashes from boilers.

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    Van Tran, A

    2008-07-01

    The effectiveness of the bottom ashes from biomass and coal-fired boilers in removing chemical oxygen demand (COD) and colorloads in effluents of a kraft pulp bleachery plant is investigated. The effluents tested are those of the sulfuric acid treatment (A stage) of a hardwood kraft pulp, and of the first acidic (chlorine or chlorine dioxide) and second alkaline (extraction) stages in the chlorine and elemental chlorine-free (ECF) bleaching lines of hardwood and softwood kraft pulps. The coal-fired boiler's bottom ashes are unable to remove either COD or color load in the bleached kraft pulp effluents. However, the bottom ashes of the biomass boiler are effective in removing COD and color loads of the acidic and alkaline effluents irrespective of the bleaching process or wood species. In particular, these ashes increase the pH of all the effluents examined.

  4. Study on the Modification of Bleached Eucalyptus Kraft Pulp Using Birch Xylan

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    Wenjia Han; Chuanshan Zhao; Thomas Elder; Rendang Yang; Dongho Kim; Yunqiao Pu; Jeffery Hsieh; Arthur J. Ragauskas

    2012-01-01

    In this study, birch xylan was deposited onto elementally chlorine free (ECF) bleached eucalyptus kraft pulp, and the corresponding changes in physical properties were determined. An aqueous 5% birch xylan solution at pH 9 was added to 5 wt% slurry of bleached kraft eucalyptus fibers, with stirring at 70 C for 15 min after which the pH was adjusted to 5–6. The xylan...

  5. Performance of Schizolobium amazonicum Wood in Bleached Kraft Pulp Production

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    Camila Sarto

    2015-05-01

    Full Text Available This study aimed to evaluate the characteristics of Schizolobium amazonicum wood, specifically its performance in bleached kraft pulp production and the characteristics of its pulp. Chips of Schizolobium amazonicum and Eucalyptus grandis x Eucalyptus urophylla (reference were used. The following parameters were evaluated in the wood: basic density, total extractives, total lignin, holocellulose, and fiber morphology. The pulping simulations were carried out in a laboratory digester, with parameters set to obtain pulp with kappa number 19 ± 0.5. Both pulps were bleached in a PFI mill and submitted to physical-mechanical tests. The results showed that S. amazonicum wood has low basic density and higher content of extractives when compared to E. grandis x E. urophylla wood. For pulping, S. amazonicum required higher alkali charge and H factor to achieve the same delignification level of E. grandis x E. urophylla, resulting in a lower yield, pulp with lower viscosity, and higher wood specific consumption. During bleaching, the brightness gain and final viscosity of S. amazonicum pulp were lower than E. grandis x E. urophylla pulp. Moreover, S. amazonicum pulp had worse physical-mechanical characteristics than E. grandis x E. urophylla.

  6. The role of bound chlorine in the brightness reversion of bleached hardwood kraft pulp

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    Kátia Maria Morais Eiras

    2009-01-01

    Full Text Available Our previous paper showed fragmentary evidence that pulp brightness reversion may be negatively affected by its organically bound chlorine (OX content. A thorough investigation on eucalyptus kraft pulp led to the conclusion that OX increases reversion of certain pulps but this trend is not universal. Alkaline bleaching stages decrease reversion regardless of pulp OX content. Pulps bleached with high temperature chlorine dioxide revert less than those bleached with conventional chlorine dioxide in sequences ending with a chlorine dioxide stage but similarly in sequences ending with a final peroxide stage. The use of secondary condensate for pulp washing decreases reversion.

  7. Effects of the bleaching sequence on the optical brighteners action in eucalyptus kraft pulp

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    Mauro Manfredi

    2014-06-01

    Full Text Available During the bleaching process the pulp is treated with chemical reagents that can be retained in the pulp and interfere in the action of the optical brighteners. Different bleaching sequences can produce pulps at the same brightness but with different potential to whiteness increase when treated with optical brighteners. The objective of this study was to evaluate the influence of the bleaching sequence on the efficiency of disulphonated and tetrasulphonated optical brighteners. Eucalyptus kraft pulp was bleached using four different bleaching sequences. For each pulp three brightness targets were aimeds. For each bleaching sequence mathematical model was generated for predicting the final pulp whiteness according to the initial brightness and the optical brightener charge applied. The presence of organochlorine residues in the pulp reduced the effectiveness of the optical brighteners. Therefore, bleaching sequences that use low chlorine dioxide charge favors for greater gains in whiteness with the application of optical brighteners. The replacement of the final chlorine dioxide bleaching stage with a hydrogen peroxide one in the sequence increased the efficiency of the optical brightening agents.

  8. Kraft pulp bleaching with molybdenum activated acid peroxide (PMo stage)

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    Rabelo, Marcos Sousa

    2009-01-01

    Optimum conditions to run the P Mo stage for bleaching eucalyptus kraft pulp were 90 deg C, pH 3.5, 2 h, 0.1 kg/t Mo and 5 kg/t H 2 O 2 . The P Mo stage efficiency increased with decreasing pH (1.5-5.5) and increasing temperature (75-90 deg C), time (2-4 h), and hydrogen peroxide (3-10 kg/t) and molybdenum concentration (0.1-0.4 kg/t). The implementation of the P Mo stage, as replacement for the A stage, decreased total active chlorine demand of the OAZDP sequence by 6 kg/t to reach 90% ISO, both in laboratory and mill scale. Such practice resulted in decreased bleaching chemical costs to produce fully bleached pulp of 90% ISO. (author)

  9. Application of xylanases from Amazon Forest fungal species in bleaching of eucalyptus kraft pulps

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    Roseli Garcia Medeiros

    2007-03-01

    Full Text Available Crude xylanase preparations from Penicillium corylophilum, Aspergillus niger and Trichoderma longibrachiatum were used to treat Eucalyptus kraft pulp, prior to chlorine dioxide and alkaline bleaching sequences. The enzyme pretreatment improved brightness and delignification of non-delignified and oxygen-bleached samples of eucalyptus kraft pulp. Xylanase preparations from T. longibrachiatum and P. corylophilum were more effective to reduce pulp kappa number. A small reduction in viscosity was obtained when the oxygen-bleached pulp was treated with xylanase preparation from A. niger. For all enzyme samples, the best release of chromophoric material from the pulp was at 237 nm. The enzyme preparation from P. corylophilum was responsible for the highest release of reducing sugar at a dosage interval of 10-20 IU/g dry weight pulp. Scanning electron microscopy studies of oxygen-bleached pulp after xylanase treatment revealed morphological changes, including holes, cracks, filament forming and peeling.Amostras de xilanases de extratos brutos de Penicillium corylophilum, Aspergillus niger e Trichoderma longibrachiatum foram utilizadas no branqueamento de polpa kraft de eucalipto antes das seqüências alcalina e dióxido de cloro. O pré-tratamento enzimático melhorou a alvura e o processo de deslignificação de amostras de polpa kraft de eucalipto não-tratada e tratada com oxigênio. Amostras de xilanases de T. longibrachiatum e P. corylophilum foram mais efetivas na redução do número kappa da polpa. A polpa tratada com oxigênio sofreu uma pequena redução na sua viscosidade quando incubada com amostra de xilanase de A. niger. Para todas as amostras de xilanases, a maior liberação de cromóforos da polpa foi a 237 nm. A amostra de xilanase de P. corylophilum liberou maior quantidade de açúcar redutor da polpa, utilizando dosagem de 10-20 UI/g de peso seco da polpa. Estudos de microscopia eletrônica de varredura revelaram várias altera

  10. Arundo donax L. reed: new perspectives for pulping and bleaching. Part 4. Peroxide bleaching of organosolv pulps.

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    Shatalov, A A; Pereira, H

    2005-05-01

    A comparative study on TCF (totally chlorine-free) bleachability of organosolv pulps from the annual fibre crop Arundo donax L. (giant reed) was carried out using a simple three-stage peroxide bleaching sequence without oxygen pre-bleaching. ASAM (alkali-sulfite-anthraquinone-methanol), Organocell (alkali-anthraquinone-methanol) and ethanol-soda organosolv pulps were bleached and compared with kraft pulp, as a reference. The final brightness of 76-78% ISO was attained for all tested pulps. The chemical charge required to reach this level of brightness varied for different pulps (despite the equal initial content of the residual lignin) and directly related to starting brightness values. No direct correlation between brightness improvement and lignin removal during bleaching was found, indicating the influence of the specific pulp properties introduced by pulping process on bleaching chemistry. The general higher bleaching response of organosolv pulps from A. donax was noted in comparison with kraft.

  11. Reinforcing Natural Rubber with Cellulose Nanofibrils Extracted from Bleached Eucalyptus Kraft Pulp

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    Chunmei Zhang; Tianliang Zhai; Ronald Sabo; Craig Clemons; Yi Dan; Lih-Sheng Turng

    2014-01-01

    Reinforced natural rubber (NR) nanocomposites were prepared by solution mixing, casting, and evaporation of pre-vulcanized natural rubber latex and an aqueous suspension of cellulose nanofibrils (CNFs) extracted from bleached eucalyptus kraft pulp. Scanning electron microscopy (SEM) images showed that there were no micro-scaled aggregates observed in the nanocomposites...

  12. ON THE RECOVERY OF HEMICELLULOSE BEFORE KRAFT PULPING

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    Carlos Vila,

    2012-07-01

    Full Text Available To assess the feasibility of implementing hemicellulose recovery stages in kraft mills, Eucalyptus globulus wood samples were subjected to aqueous treatments with hot, compressed water (autohydrolysis processing to achieve partial dissolution of xylan. Autohydrolyzed solids were subjected to kraft pulping under selected conditions to yield a pulp of low kappa number, and to an optimized TCF bleaching sequence made up of three stages (alkaline oxygen delignification, chelating, and pressurized hydrogen peroxide, with minimized additions of pulping and bleaching chemicals. The final product had a relatively low kappa number (1.4, 641 mL/g ISO intrinsic viscosity, and 86.4% brightness.

  13. Studies of lignin transformation in polyoxometalate (POM) bleaching of kraft pulp

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    Biljana Bujanovic; Richard S. Reiner; Kolby C. Hirth; Sally A. Ralph; Rajai H. Atalla

    2005-01-01

    In order to elucidate changes occurring in lignin during polyoxometalate delignification of kraft pulp, residual lignins of a series of POM- delignified kraft pulps of decreasing kappa number were isolated and characterized. Oxidative treatment of commercial unbleached kraft pulp was performed using complex POM solutions containing the active [SiVW11O40]anion. For...

  14. Kinetics of Strong Acid Hydrolysis of a Bleached Kraft Pulp for Producing Cellulose Nanocrystals (CNCs)

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    Qianqian Wang; Xuebing Zhao; J.Y. Zhu

    2014-01-01

    Cellulose nanocrytals (CNCs) are predominantly produced using the traditional strong acid hydrolysis process. In most reported studies, the typical CNC yield is low (approximately 30%) despite process optimization. This study investigated the hydrolysis of a bleached kraft eucalyptus pulp using sulfuric acid between 50 and 64 wt % at temperatures of 35−80 °C...

  15. Biochemical methane potential of kraft bleaching effluent and codigestion with other in-mill streams

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    Fitamo, Temesgen Mathewos; Dahl, Olli; Master, Emma

    2016-01-01

    and in combination: total bleaching effluent, alkaline bleaching effluent, kraft evaporator condensate, and chemithermomechanical pulping effluent. The total bleaching effluent, consisting of the chlorine dioxide bleaching and alkaline bleaching effluents, exhibited the highest potential for organic matter...

  16. Enzymes improve ECF bleaching of pulp

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    Lachenal, D.

    2006-07-01

    Full Text Available The delignification efficiency of different laccase enzymes was examined on the eucalyptus Kraft pulp. The laccase enzyme from Trametes versicolor showing the highest delignification efficiency was selected and used in the elemental chlorine-free bleaching sequence for improving the pulp bleachability. An appreciable reduction in chlorine dioxide consumption was also obtained. Further reduction in chlorine dioxide consumption was obtained when the same laccase treated pulp was subjected to an acid treatment after the extraction stage followed by the DEPD sequence. Elemental-chlorine free bleaching was also performed using the xylanase-laccase treated pulp. Xylanase treatment was incorporated to the laccase mediator system in the elemental-chlorine free bleaching both sequentially and simultaneously. The bleaching sequence DEPD followed and in both the cases, the reduction in chlorine dioxide consumption was greater in comparison to the control. The chlorine dioxide consumption was reduced further when xylanase-laccase treated pulp was given an additional acid treatment. The final pulp properties of the treated pulps were comparable to the control pulp.

  17. Kraft pulp bleaching with molybdenum activated acid peroxide (P{sub Mo} stage); Branqueamento de polpa celulosica kraft de eucalipto com peroxido acido ativado por molibdenio

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    Rabelo, Marcos Sousa [Servico Nacional de Aprendizagem Industrial (SENAI), Lauro de Freitas, BA (Brazil). Dept. Regional da Bahia; Silva, Vanessa Lopes; Barros, Denise Pires de; Colodette, Jorge Luiz [Universidade Federal de Vicosa (UFV), MG (Brazil). Dept. de Engenharia Florestal; Sacon, Vera Maria; Silva, Marcelo Rodrigues da [Votorantim Celulose e Papel, Jacarei, SP (Brazil)

    2009-07-01

    Optimum conditions to run the P{sub Mo} stage for bleaching eucalyptus kraft pulp were 90 deg C, pH 3.5, 2 h, 0.1 kg/t Mo and 5 kg/t H{sub 2}O{sub 2}. The P{sub Mo} stage efficiency increased with decreasing pH (1.5-5.5) and increasing temperature (75-90 deg C), time (2-4 h), and hydrogen peroxide (3-10 kg/t) and molybdenum concentration (0.1-0.4 kg/t). The implementation of the P{sub Mo} stage, as replacement for the A stage, decreased total active chlorine demand of the OAZDP sequence by 6 kg/t to reach 90% ISO, both in laboratory and mill scale. Such practice resulted in decreased bleaching chemical costs to produce fully bleached pulp of 90% ISO. (author)

  18. The impact of kappa number composition on eucalyptus kraft pulp bleachability

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    M. M. Costa

    2007-03-01

    Full Text Available Consumption of chemicals during ECF bleaching of kraft pulp correlates reasonably well with kappa number, which measures with KMnO4 the total amount of oxidizable material in the pulp. However, the method does not distinguish between the oxidizable material in residual lignin and other structures susceptible to oxidation, such as hexenuronic acids (HexAs, extractives and carbonyl groups in the pulp. In this study an attempt is made to separate the main contributors to the kappa number in oxygen - delignified eucalyptus Kraft pulps and evaluate how these fractions behave during ECF bleaching using chlorine dioxide as the sole oxidant (DEDD sequence. Residual lignin and HexAs proved to be the main fractions contributing to the kappa number and chlorine dioxide consumption in ECF bleaching. Pulp bleachability with chlorine dioxide increases with increasing HexAs content of the pulp but chlorine dioxide per se does not react with HexAs. Reduction of pulp with sodium borohydride under conditions for removing carbonyl groups has no impact on bleachability. No correlation was found between the pulp of the extractive content and pulp bleachability. The removal of HexAs prior to ECF bleaching significantly decreases the formation of chlorinated organics in the pulp (OX and filtrates (AOX as well as of oxalic acids in the filtrates.

  19. BLEACHING EUCALYPTUS PULPS WITH SHORT SEQUENCES

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    Flaviana Reis Milagres

    2011-03-01

    Full Text Available Eucalyptus spp kraft pulp, due to its high content of hexenuronic acids, is quite easy to bleach. Therefore, investigations have been made attempting to decrease the number of stages in the bleaching process in order to minimize capital costs. This study focused on the evaluation of short ECF (Elemental Chlorine Free and TCF (Totally Chlorine Free sequences for bleaching oxygen delignified Eucalyptus spp kraft pulp to 90% ISO brightness: PMoDP (Molybdenum catalyzed acid peroxide, chlorine dioxide and hydrogen peroxide, PMoD/P (Molybdenum catalyzed acid peroxide, chlorine dioxide and hydrogen peroxide, without washing PMoD(PO (Molybdenum catalyzed acid peroxide, chlorine dioxide and pressurized peroxide, D(EPODP (chlorine dioxide, extraction oxidative with oxygen and peroxide, chlorine dioxide and hydrogen peroxide, PMoQ(PO (Molybdenum catalyzed acid peroxide, DTPA and pressurized peroxide, and XPMoQ(PO (Enzyme, molybdenum catalyzed acid peroxide, DTPA and pressurized peroxide. Uncommon pulp treatments, such as molybdenum catalyzed acid peroxide (PMo and xylanase (X bleaching stages, were used. Among the ECF alternatives, the two-stage PMoD/P sequence proved highly cost-effective without affecting pulp quality in relation to the traditional D(EPODP sequence and produced better quality effluent in relation to the reference. However, a four stage sequence, XPMoQ(PO, was required to achieve full brightness using the TCF technology. This sequence was highly cost-effective although it only produced pulp of acceptable quality.

  20. Alkaline peroxide treatment of ECF bleached softwood kraft pulps: part 2. effect of increased fiber charge on refining, wet-end application, and hornification

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    Zheng Dang; Thomas Elder; Jeffery S. Hsieh; Arthur J. Ragauskas

    2007-01-01

    The effect of increased fiber charge on refining, cationic starch adsorption, and hornification was examined. Two pulps were investigated: (1) a softwood (SW) kraft pulp (KP) which was bleached elementally chlorine-free (ECF) and sewed as control; and (2) a control pulp treated with alkaline peroxide, which had a higher fiber charge. It was shown that increased fiber...

  1. Understanding the Nature and Reactivity of Residual Lignin for Improved Pulping and Bleaching Efficiency

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    Yuan-Zong Lai

    2001-11-30

    One of the most formidable challenges in kraft pulping to produce bleached chemical pulps is how to effectively remove the last 5-10% of lignin while maintaining the fiber quality. To avoid a severe fiber degradation, kraft pulping is usually terminated in the 25-30 kappa number range and then followed by an elementally chlorine free (ECF) or a totally chlorine free (TCF) bleaching sequence to reduce the environmental impacts.

  2. Understanding the Nature and Reactivity of Residual Lignin for Improved Pulping and Bleaching Efficiency; FINAL

    International Nuclear Information System (INIS)

    Yuan-Zong Lai

    2001-01-01

    One of the most formidable challenges in kraft pulping to produce bleached chemical pulps is how to effectively remove the last 5-10% of lignin while maintaining the fiber quality. To avoid a severe fiber degradation, kraft pulping is usually terminated in the 25-30 kappa number range and then followed by an elementally chlorine free (ECF) or a totally chlorine free (TCF) bleaching sequence to reduce the environmental impacts

  3. Kraft pulping and ECF bleaching of Eucalyptus globulus pretreated by the white-rot fungus Ceriporiopsis subvermispora - doi: 10.4025/actascitechnol.v34i3.12410

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    Claudio Salazar

    2012-05-01

    Full Text Available Eucalyptus globulus wood chips were decayed by the lignin-degrading fungus Ceriporiopsis subvermispora as a pretreatment step before kraft pulping. Weight and component losses of wood after the biotreatment were the following: weight (5%, glucans (1.5%, xylans (4.3%, lignin (5.7% and extractives (57.5%. The residual amount of lignin (expressed by the kappa number in pulps from biotreated wood chips was lower than that of pulps from the undecayed control. Depending on the delignification degree, kraft biopulps presented similar or up to 4% increase in pulp yield and 20% less hexenuronic acids (HexA than control pulps. The extended delignification with O2 decreases approximately 50% of the kappa number of the pulps and increases brightness, but had no effect in HexA reduction. The bleaching steps with chlorine dioxide (D0ED1 sequence decreased the kappa number up to 97%, increased pulp brightness up to 84% ISO and decreased HexA amount up to 91%. The use of C. subvermispora in biopulping of E. globulus generated important benefits during the production of kraft pulps that are reflected in a high pulp yield, low residual lignin content, low HexA amount, high brightness and viscosity of the biopulps as compared with pulps produced from untreated wood chips.

  4. Influence of bleaching technologies on the aerobic biodegradability of effluents from Eucalyptus kraft pulps factories

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    Gladys Vidal

    1999-01-01

    Full Text Available Aerobic biodegradability of effluents from different Eucalyptus kraft pulp bleaching processes was studied. Bleaching effluents were obtained from: i Chlorine Bleaching (CB processes, with partial substitution of chlorine by chlorine dioxide and ii Total Chlorine Free (TCF processes. The overall biodegradability, in terms of Chemical Oxygen Demand (COD was higher for TCF effluents (96-98% than for CB ones (82-93%. Taking into account the higher organic load of CB effluents, this fact implied a much higher residual COD for them (100-180 mg/L than for TCF effluents (10-30 mg/L. Furthermore, a refractory fraction of molecular weight higher than 43,000 Da was found in CB effluent, which implied the necessity of a further specific treatment. The toxicity was completely removed after the biological treatmentA biodegradabilidade aerobica das águas residuais provenientes de diferentes procesos de branqueos de pulpa kraft foi estudada. Os efluentes são gerados no branqueo com cloro ou parcialmente sustituido com dioxido de cloro (CB ou bem em processos livres do cloro (TCF. A biodegradabilidade, quantificada como DQO foi maior para as águas do processo CB. Tendo em conta o elevado conteúdo orgânico do efluente CB obteinse uma maior concentraç&ão do DQO final neste efluente comparado com o efluente TCF. Uma fracçao recalcitrante maior a 43,000 Da no effluente BC foi encontrada, isto significa um tratamento adicional específico para sua eliminaçã o. A toxicidade foi totalmente eliminada despois do tratamento aeração.

  5. Evaluation of bleachability on pine and eucalyptus kraft pulps

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    Marcela Freitas Andrade

    2013-09-01

    Full Text Available In recent decades, the pulp industry has been changing and improving its manufacturing processes in order to enhance production capacity, product quality and environmental performance. The aim of this study was to evaluate the bleachability effect on the efficient washing and alkaline leaching in eucalyptus and pine Kraft pulps using three different bleaching sequences: AD(EPD, A/D(EPDP and DHT(EPDP. This study was carried out in two stages. In the first part, the optimum conditions for pulp bleaching in order to achieve a brightness of 90% ISO were established. The second step was a comparative study between the pulps that received alkaline leaching and efficient washing with reference pulp (without treatment. The brightness, viscosity, kappa number and HexA in pulp were analyzed. The three sequences studied reached the desired brightness, but the sequence AD(EPD produced a lower reagent consumption for the same brightness. In the three sequences studied, the efficient washing of the pulp after oxygen delignification has contributed significantly to the removal of dissolved organic and inorganic materials in the pulp and the alkaline leaching decreased significantly the pulp kappa number due to a higher pulp delignification and bleachability.

  6. Improved pulp bleaching potential of Bacillus subtilis WB800 through overexpression of three lignolytic enzymes from various bacteria.

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    Ozer, Aysegul; Uzuner, Ugur; Guler, Halil Ibrahim; Ay Sal, Fulya; Belduz, Ali Osman; Deniz, Ilhan; Canakci, Sabriye

    2017-12-29

    A chemical bleaching process of paper pulps gives off excessive amount of chlorinated organic wastes mostly released to environment without exposing complete bioremediaton. Recent alternative and eco-friendly approaches toward pulp bleaching appear more responsive to environmental awareness. Here we report, direct use of a recombinant Bacillus subtilis bacterium for pulp bleaching, endowed with three ligninolytic enzymes from various bacteria. In addition, efficient bleaching performance from glutathione-S-transferase (GST) biocatalyst tested for the first time in pulp bleaching applications was also achieved. Simultaneous and extracellular overproduction of highly active GST, laccase, and lignin peroxidase catalysts were also performed by Bacillus cells. Both enhanced bleaching success and improved delignification rates were identified when enzyme combinations tested on both pine kraft and waste paper pulps, ranging from 69.75% to 79.18% and 60.89% to 74.65%, respectively. Furthermore, when triple enzyme combination applied onto the papers from pine kraft and waste pulps, the best ISO brightness values were identified as 66.45% and 64.67%, respectively. The delignification rates of pulp fibers exposed to various enzymatic bleaching sequences were comparatively examined under SEM. In conclusion, the current study points out that in near future, a more fined-tuned engineering of pulp-colonizing bacteria may become a cost-effective and environmentally friendly alternative to chemical bleaching. © 2017 International Union of Biochemistry and Molecular Biology, Inc.

  7. MOLYBDENUM CATALYZED ACID PEROXIDE BLEACHING OF EUCALYPTUS KRAFT PULP

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    Marcos S. Rabelo

    2008-08-01

    Full Text Available Molybdenum catalyzed peroxide bleaching (PMo Stage consists of pulp treatment with hydrogen peroxide under acidic conditions in the presence of a molybdenum catalyst. Molybdenum is applied in catalytic doses (50-200 mg/kg pulp and may originate from various sources, including (NH46Mo7O24.4H2O, Na2MoO4.2H2O, siliconmolybdate, etc. This work is aimed at optimizing the PMo stage and evaluating its industrial application in the OAZDP sequence. Optimum PMo stage conditions for bleaching eucalyptus pulp were 90 ºC, pH 3.5, 2 h, 0.1 kg/adt Mo and 5 kg/adt H2O2. The PMo stage was more efficient to remove pulp hexenuronic acids than lignin. Its efficiency decreased with increasing pH in the range of 1.5-5.5, while it increased with increasing temperature and peroxide and molybdenum doses. The application of the PMo stage as replacement for the A-stage of the AZDP sequence significantly decreased chlorine dioxide demand. The PMo stage caused a decrease of 20-30% in the generation of organically bound chlorine. The quality parameters of the pulp produced during the PMo stage mill trial were comparable to those obtained with the reference A-stage.

  8. Mesta/Kenaf as raw material for Kraft pulping

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    Saraf, V. P.; Shiveshwar, R. M.; Meshramkar, P. M.; Deb, U. K.; Jaspal, N. S.; Biyani, B. P.

    1980-03-15

    In recent years, the shortage of conventional raw materials for pulping has intensified a world-wide search for alternate raw materials. Among other cellulosic materials, attention has focused on agricultural residues and annual plants. In this category, Kenaf, also called Mesta, has been studied as a fiber source in many countries including the USA, Phillippines and India. A comprehensive study on kraft pulping of mesta was carried out where the fiber morphology, pulping, bleaching and papermaking characteristics were investigated. Black liquor properties were also determined. The results of this study are reported and compared to the conventional raw material bamboo. The investigation has shown that mesta is easily pulped and bleached and forms sheets of excellent strength properties, comparable to or better than bamboo pulps. The black liquor from mesta is similar to bamboo in calorific value but is very low in silica, which is highly desirable from the chemical recovery point of view. As with all agricultural residues and annual plants, mesta has a high bulk per unit weight. The problems arising from this, e.g., baling, transportation, proper utilization of digester capacity, have to be studied before mesta can be widely accepted in the paper industry.

  9. Detoxification of kraft pulp ECF bleaching effluents by catalytic hydrotreatment.

    Science.gov (United States)

    Calvo, L; Gilarranz, M A; Casas, J A; Mohedano, A F; Rodríguez, J J

    2007-02-01

    Two different effluents from the D(1) and E(1) stages of the ECF bleaching of Eucalyptus globulus kraft pulp were treated by catalytic hydrogenation in a trickle bed reactor using commercial and homemade Pd/AC catalysts. The reactor was fed with the bleaching effluent and a H(2)/N(2) gas stream. The variables studied were space-time (1.4-5g(cat)min/mL), gas to liquid flow ratio (286-1000vol.), gas feed concentration (H(2):N(2), 1:1-1:7.3vol.), temperature (25-100 degrees C) and pressure (1-11bar). Hydrotreatment performance was evaluated in terms of ecotoxicity, adsorbable organic halogen (AOX), chemical oxygen demand (COD), biological oxygen demand (BOD(5)) and colour removal. In all the runs, the ecotoxicity of the effluents decreased as a result of the treatment, achieving reductions that ranged from 70% to 98%. Simultaneously to the reduction of toxicity, the hydrotreatment led to a decrease of the colour of the effluents, being the decrease significantly higher in the case of E(1) effluent. The AOX content was reduced by 85% and 23% for E(1) and D(1) effluents, respectively. In the case of D(1) effluent the removal of ecotoxicity was significantly higher than that of AOX, which indicates that much of the toxicity of the effluent must be associated to non-chlorinated organics. In spite of the important reduction of ecotoxicity, the biodegradability of the effluents only increased slightly. The homemade catalysts, prepared from activated carbons with a high external or non-microporous surface area and mesopore volume and a convenient surface chemistry showed a higher efficiency than the commercial one.

  10. Effect of Cellulases and Xylanases on Refining Process and Kraft Pulp Properties.

    Directory of Open Access Journals (Sweden)

    Kamila Przybysz Buzała

    Full Text Available Samples of bleached kraft pine cellulosic pulp, either treated with an enzyme preparation (a Thermomyces lanuginosus xylanase, an Aspergillus sp. cellulase, and a multienzyme preparation NS-22086 containing both these activities or untreated, were refined in a laboratory PFI mill. The treatment with cellulases contained in the last two preparations significantly improved the pulp's susceptibility to refining (the target freeness value of 30°SR was achieved in a significantly shorter time, increased water retention value (WRV and fines contents while the weighted average fiber length was significantly reduced. These changes of pulp parameters caused deterioration of paper strength properties. The treatment with the xylanase, which partially hydrolyzed xylan, small amounts of which are associated with cellulose fibers, only slightly loosened the structure of fibers. These subtle changes positively affected the susceptibility of the pulp to refining (refining energy was significantly reduced and improved the static strength properties of paper. Thus, the treatment of kraft pulps with xylanases may lead to substantial savings of refining energy without negative effects on paper characteristics.

  11. 78 FR 31315 - Kraft Pulp Mills NSPS Review

    Science.gov (United States)

    2013-05-23

    ... Kraft Pulp Mills NSPS Review; Proposed Rule #0;#0;Federal Register / Vol. 78 , No. 100 / Thursday, May...-OAR-2012-0640; FRL-9815-9] RIN 2060-AR64 Kraft Pulp Mills NSPS Review AGENCY: Environmental Protection... performance standards for kraft pulp mills. These revised standards include particulate matter emission limits...

  12. Sodium Hydroxide and Calcium Hydroxide Hybrid Oxygen Bleaching with System

    Science.gov (United States)

    Doelle, K.; Bajrami, B.

    2018-01-01

    This study investigates the replacement of sodium hydroxide in the oxygen bleaching stage using a hybrid system consisting of sodium hydroxide calcium hydroxide. Commercial Kraft pulping was studied using yellow pine Kraft pulp obtained from a company in the US. The impact of sodium hydroxide, calcium hydroxide hybrid system in regard to concentration, reaction time and temperature for Kraft pulp was evaluated. The sodium hydroxide and calcium hydroxide dosage was varied between 0% and 15% based on oven dry fiber content. The bleaching reaction time was varied between 0 and 180 minutes whereas the bleaching temperature ranged between 70 °C and 110 °C. The ability to bleach pulp was measured by determining the Kappa number. Optimum bleaching results for the hybrid system were achieved with 4% sodium hydroxide and 2% calcium hydroxide content. Beyond this, the ability to bleach pulp decreased.

  13. Alkaline pulping of some eucalypts from Sudan.

    Science.gov (United States)

    Khristova, P; Kordsachia, O; Patt, R; Dafaalla, S

    2006-03-01

    Four eucalypts (Eucalyptus camaldulensis, Eucalyptus microtheca, Eucalyptus tereticornis and Eucalyptus citriodora) grown in Sudan were examined for their suitability for pulping and papermaking with different alkaline methods. Their physical, morphological and chemical characteristics are reported. The pulping trials with E. citriodora and E. tereticornis were carried out using the kraft-AQ, soda-AQ, modified AS/AQ (ASA), ASAM and kraft methods. For the other two species, only the ASAM and the kraft process were applied. ASAM pulping gave the best results in terms of yield, degree of delignification, mechanical and optical pulp properties. The best pulps, obtained in kraft and ASAM cooking of E. citriodora, were bleached to 88% ISO brightness in a totally chlorine free bleaching sequence (OQ1O/PQ2P). The bleached pulps, especially the ASAM pulp, showed good papermaking properties and would be suitable for manufacture of writing and printing grades of paper.

  14. STUDIES ON HIBISCUS CANNABINUS, HIBISCUS SABDARIFFA, AND CANNABINUS SATIVA PULP TO BE A SUBSTITUTE FOR SOFTWOOD PULP- PART 1: AS-AQ DELIGNIFICATION PROCESS

    OpenAIRE

    Dharm Dutt; J. S. Upadhyaya; C. H. Tyagi

    2010-01-01

    Hibiscus cannabinus, Hibiscus sabdariffa, and Cannabinus sativa, which are renewable non-woody fiber resources having characteristics similar to that of softwood (bast fibers), when used together with hardwood (core fibers), gave higher pulp yield with good mechanical strength properties when using an alkaline sulphite-anthraquinone (AS-AQ) pulping process rather than a conventional kraft pulping process and bleached more readily than kraft and soda pulps with a CEHH bleaching sequence. A com...

  15. 78 FR 38877 - Kraft Pulp Mills NSPS Review

    Science.gov (United States)

    2013-06-28

    ... ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 60 [EPA-HQ-OAR-2012-0640] FRL-9829-3 RIN 2060-AR64 Kraft Pulp Mills NSPS Review AGENCY: Environmental Protection Agency (EPA). ACTION: Proposed rule... comments on the May 23, 2013, proposed rule titled, ``Kraft Pulp Mills NSPS Review'' is being extended by...

  16. Ozone bleaching of South African Eucalyptus grandis kraft pulps containing high levels of hexenuronic acids

    CSIR Research Space (South Africa)

    Andrew, JE

    2013-08-01

    Full Text Available Ozone use in conjunction with chlorine dioxide during pulp bleaching offers several advantages over conventional bleaching sequences that make use of chlorine dioxide only. Despite this, in South Africa, only one mill uses ozone. The current study...

  17. Control of the Accumulation of Non-Process Elements in Pulp Mills with Bleach Filtrate Reuse: A Chemical Equilibrium Approach to Predicting the Partitioning of Metals in Pulp Mill and Bleach Plant Streams

    Energy Technology Data Exchange (ETDEWEB)

    Frederick, W.J. Jr.; Rudie, A.W.; Schmidl, G.W.; Sinquefield, S.A.; Rorrer, G.L.; Laver, M.L.; Yantasee, W.; Ming, D.

    2000-08-01

    The overall goal of this project was to develop fundamental, experimentally based methods for predicting the solubility or organic and inorganic matter and their interactions in recycled effluent from kraft pulp mills and bleach plants. This included: characterizing the capacity of wood pulp and dissolved organic matter to bind metal ions, developing a thermodynamic database of properties needed to describe the solubility of inorganic matter in pulp mill streams, incorporation of the database into equilibrium calculation software for predicting the solubility of the metals of interest, and evaluating its capability to predict the distribution of the metals between pulp fibers, inorganic precipitates, and solution.

  18. Kraft pulping of industrial wood waste

    Science.gov (United States)

    Aziz. Ahmed; Masood. Akhtar; Gary C. Myers; Gary M. Scott

    1998-01-01

    Most of the approximately 25 to 30 million tons of industrial wood waste generated in the United States per year is burned for energy and/or landfilled. In this study, kraft pulp from industrial wood waste was evaluated and compared with softwood (loblolly pine, Douglas-fir) and hardwood (aspen) pulp. Pulp bleachability was also evaluated. Compared to loblolly pine...

  19. A practical approach towards energy conversion through bio-refining of mixed kraft pulps

    Energy Technology Data Exchange (ETDEWEB)

    Dharm, D.; Upadhyaya, J.S.; Tyagi, C.H.; Ahamad, S. (Dept. of Paper Technology, Indian Inst. of Technology Roorkee, Saharanpur (India))

    2007-07-01

    The pulp and paper industry is an energy intensive process industry where energy contributes about 16-20% of the manufacturing cost. Due to shortage in energy availability and increase in energy cost, energy conservation has become a necessity in the paper industry. A laboratory study on bleached and unbleached kraft pulps having 15% bamboo, eucalyptus 15%, poplar waste 20% and veneer waste 50% was conducted using two distinct commercial enzymes i.e. cellulases and xylanase and its effect on slowness, drainage time, beating time, mechanical strength properties and power consumption were studied. Enzymatic pretreatment of chemical pulp in laboratory improves degSR by 5 and 4 points in case of bleached and unbleached pulps respectively at the same beating time. Breaking length improves up to 4.0% at the constant beating level. The application of cellulase during refining saves energy 18.5% at constant refining level i.e. 28 degSR. The enzymatic treatment shows a power saving per 100 metric tone of paper by 1390 kWh which costs power saving in euro 160.70/ 100 metric tone of paper. In this way, net cost saving by deducting the cost of enzyme per 100 metric tone of paper is euro 157.90. (orig.)

  20. Amenability of Acacia and Eucalyptus Hardwood Pulps to Elemental Chlorine-Free Bleaching: Application and Efficacy of Microbial Xylanase

    Directory of Open Access Journals (Sweden)

    Avdhesh Kumar Gangwar

    2015-10-01

    Full Text Available This study outlines the results of a biobleaching study of acacia (A. mangium and eucalyptus (E. globulus hardwood kraft pulps with commercial xylanase (Optimase CX 72 L. The comparative study was carried out using an elemental chlorine-free (ECF bleaching sequence (D0EPD1D2 after the enzyme (X stage. The enzyme treatment resulted in improved optical properties with a reduction in bleach chemical consumption. At an equivalent bleach chemical consumption, a brightness gain of 2.1 and 1.7 units and a whiteness gain of 2.7 and 2.3 units were observed with xylanase treatment in acacia and eucalyptus pulps, respectively. In ECF bleaching using the D0EPD1D2 sequence, a final brightness was achieved to the extent of 90% ISO and 89% ISO for acacia and eucalyptus, respectively, at an equivalent charge of bleach chemicals. The post-color (PC number was also reduced by up to 45% for both hardwood pulps compared with the control. The bleachability of acacia was observed to be significantly higher than that of eucalyptus. In addition, a 17.0% and 23.0% reduction in chlorine dioxide and sodium hydroxide, respectively, were obtained for both hardwood pulps after xylanase pre-bleaching, thus indicating an environmentally friendly approach to the process.

  1. Membrane treatment of alkaline bleaching effluents from elementary chlorine free kraft softwood cellulose production.

    Science.gov (United States)

    Oñate, Elizabeth; Rodríguez, Edgard; Bórquez, Rodrigo; Zaror, Claudio

    2015-01-01

    This paper reports experimental results on the sequential use of ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) to fractionate alkaline extraction bleaching effluents from kraft cellulose production. The aim was to unveil the way key pollutants are distributed when subjected to sequential UF/NF/RO membrane separation processes. Alkaline bleaching effluents were obtained from a local pinewood-based mill, featuring elementary chlorine free bleaching to produce high-brightness cellulose. The experimental system was based on a laboratory-scale membrane system, DSS LabStak® M20 Alfa Laval, using Alfa Laval UF and NF/RO membranes, operated at a constant transmembrane pressure (6 bar for UF membranes and 32 bar for NF/RO membranes), at 25°C. Results show that 78% chemical oxygen demand (COD) and total phenols, 82% adsorbable organic halogens (AOX) and 98% colour were retained by UF membranes which have molecular weight cut-off (MWCO) above 10 kDa. In all, 16% of original COD, total phenols and AOX, and the remaining 2% colour were retained by UF membranes within the 1 to 10 kDa MWCO range. Chloride ions were significantly present in all UF permeates, and RO was required to obtain a high-quality permeate with a view to water reuse. It is concluded that UF/NF/RO membranes offer a feasible option for water and chemicals recovery from alkaline bleaching effluents in kraft pulp production.

  2. Eucalyptus kraft pulp production: Thermogravimetry monitoring

    International Nuclear Information System (INIS)

    Barneto, Agustin G.; Vila, Carlos; Ariza, Jose

    2011-01-01

    Highlights: → Thermogravimetric analysis can be used to monitor the pulping process in a pulp mill. → ECF bleaching process affects the crystalline cellulose volatilization. → The fibre size has an influence on composition and thermal behavior of pulp. - Abstract: Under oxidative environment the thermal degradation of lignocellulosic materials like wood or pulp is sensitive to slight composition changes. For this, in order to complement the chemical and X-ray diffraction results, thermogravimetric analyses (TGA) were used to monitor pulp production in a modern pulp mill. Runs were carried out on crude, oxygen delignified and bleached pulps from three eucalyptus woods from different species and geographical origins. Moreover, with the modeling of thermogravimetric data, it was possible to obtain an approximate composition of samples which includes crystalline and amorphous cellulose. TGA results show that pulping has an intensive effect on bulk lignin and hemicellulose, but it has limited influence on the removal of these substances when they are linked to cellulose microfibril. The stages of oxygen delignification and bleaching, based in chlorine dioxide and hydrogen peroxide, increase the crystalline cellulose volatilization rate. These changes are compatible with a more crystalline microfibril. The influence of the fibre size on pulp composition, crystallinity and thermal degradation behavior was observed.

  3. Recovery of ovary size, follicle cell apoptosis, and HSP70 expression in fish exposed to bleached pulp mill effluent

    Energy Technology Data Exchange (ETDEWEB)

    Janz, D. M.; Weber, L. P. [Oklahoma State Univ., Stillwater, OK (United States); McMaster, M. E.; Munkittrrick, K. R. [Environment Canada, Burlington, ON (Canada); Van Der Kraak, G. [Guelph Univ., Dept. of Zoology, ON (Canada)

    2001-03-01

    Apoptosis of granulosa cells that provide hormonal support for the oocyte is the normal mechanism by which atresia ( reduced ovarian size, decreased fecundity, delayed sexual maturation, alterations in plasma sex steroid levels, etc) occurs in mammals, birds and possibly fish. The objective of this study is to determine ovarian cell apoptosis, gonadosomatic index (GSI) and heat shock protein (HSP70) expression during the growth stage of ovarian development in white sucker fish in order to compare samples of fish collected upstream and downstream of a bleached kraft pulp mill in Ontario. Fish for the study were collected in two different years, before and after the pulp mill undertook a number of improvements to eliminate the release of process chemicals. Results showed a 3.4-fold increase in ovarian cell apoptosis in growing white sucker collected four km downstream of the bleached kraft pulp mill in 1996 (before the improvements) compared to fish collected from upstream sources. The elevated ovarian cell apoptosis was associated with significant reduction in gonadosomatic index in fish collected downstream. There were no differences in ovarian cell apoptosis or gonadosomatic index between fish collected upstream and four km downstream of the mill in September 1998 (after the improvements.) Based on the results, it may be concluded that chronic stimulation of ovarian cell apoptosis by certain components of bleached kraft pulp mill effluents represents an important cellular mechanism for reducing the size of ovaries and other related reproductive responses in female fish exposed to these effluents. Although the specific effluent components are not known, the improvements undertaken between 1996 and 1998 resulted in significant enough recovery of these responses to justify the belief in a cause-effect relationship. 32 refs., 1 tab., 2 figs.

  4. Bleaching of kraft pulps produced from green liquor pre-hydrolyzed South African Eucalyptus grandis wood chips

    CSIR Research Space (South Africa)

    Andrew, JE

    2014-01-01

    Full Text Available -ability. Savings in chlorine dioxide for PHK pulps ranged between 2-18% for sequences that used chlorine dioxide as the primary oxidative bleaching chemical. When ozone was used in combination with chlorine dioxide, mixed results were obtained – PHK pulps showed...

  5. Chemical characteristics and Kraft pulping of tension wood from Eucalyptus globulus labill Características químicas e polpação Kraft de madeira de tração de Eucalyptus globulus labill

    Directory of Open Access Journals (Sweden)

    María Graciela Aguayo

    2012-12-01

    Full Text Available Tension (TW and opposite wood (OW of Eucalyptus globulus trees were analyzed for its chemical characteristics and Kraft pulp production. Lignin content was 16% lower and contained 32% more syringyl units in TW than in OW. The increase in syringyl units favoured the formation of β-O-4 bonds that was also higher in TW than in OW (84% vs. 64%, respectively. The effect of these wood features was evaluated in the production of Kraft pulps from both types of wood. At kappa number 16, Kraft pulps obtained from TW demanded less active alkali in delignification and presented slightly higher or similar pulp yield than pulps made with OW. Fiber length, coarseness and intrinsic viscosity were also higher in tension than in opposite pulps. When pulps where refined to 30°SR, TW pulps needed 18% more revolutions in the PFI mill to achieve the same beating degree than OW pulps. Strength properties (tensile, tear and burst indexes were slightly higher or similar in tension as compared with opposite wood pulps. After an OD0(EOD1 bleaching sequence, both pulps achieved up to 89% ISO brightness. Bleached pulps from TW presented higher viscosity and low amount of hexenuronic acids than pulps from OW. Results showed that TW presented high xylans and low lignin content that caused a decrease in alkali consumption, increase pulp strength properties and similar bleaching performance as compared with pulps from OW.Madeira de tração e oposta de árvores de Eucalyptus globulus foram analisadas quanto a suas características químicas e produção de polpa Kraft. A caracterização química da madeira de tração (TW de Eucalyptus globulus Labill. mostrou um conteúdo similar de celulose, alto conteúdo de xilanas e baixo conteúdo de lignina quando comparada com a madeira oposta (OW de uma mesma árvore. O conteúdo de lignina foi 16% menor e contém 32% mais unidades siringila em TW que em OW. O aumento das unidades siringila favoreceu a formação de ligações

  6. Positive and negative aspects of soda/anthraquinone pulping of hardwoods.

    Science.gov (United States)

    Francis, R C; Bolton, T S; Abdoulmoumine, N; Lavrykova, N; Bose, S K

    2008-11-01

    The positive aspects of the non-sulfur soda/anthraquinone (SAQ) process are mostly tied to improved energy efficiency while lower pulp brightness after bleaching is its most significant drawback. A credible method that quantifies bleachability as well as an approach that solves the problem for SAQ pulps from hardwoods will be described. A straight line correlation (R2=0.904) was obtained between O2 kappa number and final light absorption coefficient (LAC) value after standardized OD0EpD1 bleaching of nine hardwood kraft pulps from three laboratories and one pulp mill. The bleachability of pulps from four different soda processes catalyzed by anthraquinone (AQ) and 2-methylanthraquinone (MAQ) was compared to that of conventional kraft pulps by comparing O2 kappa number decrease and final LAC values. It was observed that a mild hot water pre-hydrolysis improved the bleachability of SAQ pulps to a level equal to that of kraft.

  7. The Kraft Pulp And Paper Properties of Sweet Sorghum Bagasse (Sorghum bicolor L Moench

    Directory of Open Access Journals (Sweden)

    Widya Fatriasari

    2015-05-01

    Full Text Available This study investigated the potency of sweet sorghum (Sorghum bicolor bagasse as raw material for pulp and paper using kraft pulping. The effects of alkali and sulfidity loading on kraft pulp and paper properties were also investigated. The pulping condition of the kraft pulp consisted of three levels of alkali loading (17, 19 and 22% and sulfidity loading (20, 22 and 24%. The maximum cooking temperature was 170°C for 4 h with a liquid to wood ratio of 10:1. Kraft pulping of this Numbu bagasse produced good pulp indicated by high screen yield and delignification selectivity with a low Kappa number (< 10. The unbleached pulp sheet produced a superior brightness level and a high burst index. The increase of active alkali loading tended to produce a negative effect on the pulp yield, Kappa number and paper sheet properties. Therefore, it is suggested to use a lower active alkaline concentration.

  8. Dry Kraft Pulping at Ambient Pressure for Cost Effective Energy Saving and Pollution Deduction

    Energy Technology Data Exchange (ETDEWEB)

    Yulin Deng; Art Ragauskas

    2012-08-28

    Sponsored by the DOE Industrial Energy Efficiency Grand Challenge program, our research team at the Georgia Institute of Technology conducted laboratory studies and confirmed the concept of making wood pulp using a dry pulping technology. This technology is a new process different from any prior pulping technology used in Kraft and CTMP pulping. Three different kinds of dry pulping methods were investigated. (a) Dry Pulping at Atmospheric Pressure: The first one is to dry and bake the pretreated woodchips in a conventional oven at atmospheric pressure without the use of a catalyst. (b) Dry Pulping at Reduced Pressure: The second method is to dry the pretreated woodchips first in a vacuum oven in the presence of anthraquinone (AQ) as a pulping catalyst, followed by baking at elevated temperature. (c) Liquid Free Chemical Pulping, LFCP. The third method is to first remove the free water of pretreated woodchips, followed by dry pulping using a conventional Kraft pulping digester with AQ and triton as additives. Method one: Experimental results indicated that Dry Pulping at Atmospheric Pressure could produce pulp with higher brightness and lower bulk than conventional Kraft pulp. However, tensile strength of the acquired pulp is much lower than traditional Kraft pulp, and their Kappa number and energy consumption are higher than conventional Kraft pulp. By fully analyzing the results, we concluded that wood fibers might be damaged during the drying process at elevated temperature. The main reason for wood fiber damage is that a long drying time was used during evaporation of water from the woodchips. This resulted in an un-uniform reaction condition on the woodchips: the outside layer of the woodchips was over reacted while inside the woodchips did not reacted at all. To solve this problem, dry pulping at reduced pressure was investigated. Method two: To achieve uniform reaction throughout the entire reaction system, the water inside the pretreated woodchips was

  9. Pulp and paper production from Spruce wood with kraft and ...

    African Journals Online (AJOL)

    STORAGESEVER

    2010-03-15

    Mar 15, 2010 ... optical properties of resultant paper were included to determine the properties of these pulp samples. ... pulping compounds in the kraft method are Na2S and .... Scanning electron microscope (SEM) measurement of pulp.

  10. Efeito do conteúdo e da natureza da lignina residual na eficiência e na seletividade do branqueamento com ozônio Effect of residual lignin content and nature on the efficiency and selectivity of ozone bleaching

    Directory of Open Access Journals (Sweden)

    Elenice Pereira Maia

    2003-04-01

    Full Text Available Neste estudo foram avaliados os efeitos do conteúdo e da natureza da lignina residual na eficiência e na seletividade do branqueamento com ozônio de polpa kraft convencional (kraft e pré-deslignificada com oxigênio (kraft-O. Constatou-se que a eficiência do branqueamento com ozônio se eleva com o aumento do conteúdo de lignina residual da polpa. O tratamento com ozônio é mais seletivo para polpas kraft-O, mas para um mesmo tipo de polpa a seletividade de branqueamento com ozônio se eleva com o aumento de lignina residual. A eficiência do branqueamento com ozônio aumenta com o teor de lignina fenólica na polpa, entretanto a seletividade é negativamente afetada pela presença destas estruturas.This study aimed to evaluate the effect of residual lignin content and nature on the efficiency and selectivity of ozone bleaching of conventional (kraft and oxygen delignified (kraft-O pulps. Ozone bleaching efficiency was found to be enhanced by increasing pulp residual lignin content. Ozone treatment is more selective for kraft-O pulps, but for a given type of pulp (kraft or kraft-O, ozone bleaching selectivity increases with increasing pulp lignin content. Ozone bleaching efficiency increases with increasing pulp lignin phenolic hydroxyl content whereas selectivity is negatively affected by these structures.

  11. Effect of depth beating on the fiber properties and enzymatic saccharification efficiency of softwood kraft pulp.

    Science.gov (United States)

    Gao, Wenhua; Xiang, Zhouyang; Chen, Kefu; Yang, Rendang; Yang, Fei

    2015-01-01

    Commercial bleached softwood kraft pulp was mechanically fibrillated by a PFI-mill with beating revolution from 5000 to 30,000 r. The extent of fibrillating on the pulp was evaluated by beating degree, fiber morphological properties (fiber length, width, coarseness and curls index), water retention value (WRV) and physical properties of paper made from the pulp. Depth beating process significantly affected the pulp fibrillations as showed by the decreased fiber length and width as well as the SEM analysis, but the effects were limited after beating revolution of 15,000. Depth beating process also improved the total internal pore and inter-fibril surface areas as shown by the increased WRV values. Substrate enzymatic digestibility (SED) of beaten pulp at 5000 revolutions could reach 95% at cellulase loading of 15 FPU/g of glucan. After the enzymatic hydrolysis, the size of the pulp residues was reduced to micro-scale, and a relative uniform size distribution of the residues appeared at 10,000 r beating revolution. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Effect of Urea Addition on Soda Pulping of Oak Wood

    OpenAIRE

    Cho, Nam-Seok; Matsumoto, Yuji; Cho, Hee-Yeon; Shin, Soo-Jeong; Oga, Shoji

    2008-01-01

    Many studies have been conducted to find a sulfur-free additive for alkaline pulping liquors that would have an effect similar to that of sulfide in kraft pulping. Some reagents that partially fulfill this role have been found, but they are too expensive to be used in the quantities required to make them effective. As an alternative method to solve air pollution problem and difficulty of pulp bleaching of kraft pulping process, NaOH-Urea pulping was applied. The properties of NaOH-Urea pul...

  13. Relationship between lignin structure and delignification degree in Pinus pinaster kraft pulps.

    Science.gov (United States)

    Baptista, C; Robert, D; Duarte, A P

    2008-05-01

    This study examines the structure of residual and dissolved lignins from Pinus pinaster pulps obtained at different degrees of delignification by laboratory conventional kraft pulping. The cooking H factor was varied from 85 to 8049. The residual and dissolved lignin samples were characterised by elemental analysis, residual carbohydrate content, permanganate oxidation and 13C NMR spectroscopy. The reflectance factor of the pulps was also determined in order to tentatively correlate the delignification degree and residual lignin structure with the pulp colour. The obtained results confirmed that the delignification degree increases the condensation of the lignin structure, which might have an influence upon the observed increased pulp colour. The lack of selectivity of kraft pulping process in the case of more delignified pulps was also shown.

  14. Assessment of reproductive effects in largemouth bass (Micropterus salmoides) exposed to bleached/unbleached kraft mill effluents.

    Science.gov (United States)

    Sepúlveda, M S; Ruessler, D S; Denslow, N D; Holm, S E; Schoeb, T R; Gross, T S

    2001-11-01

    This study evaluated the potential effects of different concentrations of bleached/unbleached kraft mill effluent (B/UKME) on several reproductive endpoints in adult largemouth bass (Micropterus salmoides). The kraft mill studied produces a 50/50 mix of bleached/unbleached market pulp with an estimated release of 36 million gal of effluent/day. Bleaching sequences were C90d10EopHDp and CEHD for softwood (pines) and hardwoods (mainly tupelo, gums, magnolia, and water oaks), respectively. Bass were exposed to different effluent concentrations (0 [controls, exposed to well water], 10, 20, 40, or 80%) for either 28 or 56 days. At the end of each exposure period, fish were euthanized, gonads collected for histological evaluation and determination of gonadosomatic index (GSI), and plasma was analyzed for 17beta-estradiol, 11-ketotestosterone, and vitellogenin (VTG). Largemouth bass exposed to B/UKME responded with changes at the biochemical level (decline in sex steroids in both sexes and VTG in females) that were usually translated into tissue/organ-level responses (declines in GSI in both sexes and in ovarian development in females). Although most of these responses occurred after exposing fish to 40% B/UKME concentrations or greater, some were observed after exposures to 20% B/UKME. These threshold concentrations fall within the 60% average yearly concentration of effluent that exists in the stream near the point of discharge (Rice Creek), but are above the <10% effluent concentration present in the St. Johns River. The chemical(s) responsible for such changes as well as their mode(s) of action remain unknown at this time.

  15. PRODUCTION OF DISSOLVING GRADE PULP FROM ALFA

    Directory of Open Access Journals (Sweden)

    Baya Bouiri

    2010-02-01

    Full Text Available Alfa, also known as Stipa tenacissimaI or “halfa”, is grown in North Africa and south Spain. Due to its short fiber length, paper made from alfa pulp retains bulk and takes block letters well. In this study alfa was evaluated for bleached pulp production. Two cellulose pulps with different chemical compositions were pulped by a conventional kraft process. One sample was taken from the original alfa material and another from alfa that had been pretreated by diluted acid. The pulp produced from the pretreated alfa was bleached by the elemental-chlorine-free sequences DEPD and DEDP. The yield, Kappa number, brightness, and α- cellulose content of bleached and unbleached pulps were evaluated. The results showed that during the chemical pulping process, treated alfa cooked more easily than the original alfa. The treated alfa pulp also showed very good bleaching, reaching a brightness level of 94.8% ISO with a yield of 93.6% at an α-cellulose content 96.8(% with a DEDP bleaching sequence, compared to 83.2% ISO brightness level, 92.8% yield, and 95.1% α-cellulose content for bleached pulp with a DEPD bleaching sequence. Therefore, this alfa material could be considered as a worthwhile choice for cellulosic fiber supply.

  16. HYDROGEN PEROXIDE BLEACHING OF CMP PULP USING MAGNESIUM HYDROXIDE

    Directory of Open Access Journals (Sweden)

    Farhad Zeinaly

    2009-11-01

    Full Text Available Conventional bleaching of hardwood CMP pulp with magnesium hydroxide (Mg(OH2 show significant benefits over bleaching with sodium hydroxide (NaOH under various conditions. Magnesium hydroxide bleaching generate higher optical properties, higher pulp yield and lower effluent COD at the same chemical charge, but the physical properties were found to be similar for both processes. The initial freeness of the bleached pulps and refining value to reach a target freeness (about 350 ml. CSF were more for the Mg(OH2-based process. The residual peroxide of filtrate from the Mg(OH2-based process was very high as compared to conventional bleaching.

  17. Optimization of Dithionite Bleaching of High Yield Bagasse Pulp

    International Nuclear Information System (INIS)

    Mohamed, E.

    2005-01-01

    High yield bagasse pulp was prepared by soaking bagasse in 10 % cold sodium hydroxide for 24 hours and then refluxing for two hours at 95 degree C. Optimization of dithionite bleaching was attained by investigation of different parameters as consistency, temperature, time and ph. Effect of additives as chelating agent (EDTA) or stabilizing of bleaching solution (Zn compound and hexamethylene tetramine) was considered. The effect of air content was also studied. One and two stages bleaching of the pulp were investigated by using sodium dithionite (D) as a sole bleaching agent or after application of one stage bleaching by hydrogen peroxide to attain high brightness for high yield pulp

  18. Effects of black liquor shocks on activated sludge treatment of bleached kraft pulp mill wastewater.

    Science.gov (United States)

    Morales, Gabriela; Pesante, Silvana; Vidal, Gladys

    2015-01-01

    Kraft pulp mills use activated sludge systems to remove organic matter from effluents. Process streams may appear as toxic spills in treatment plant effluents, such as black liquor, which is toxic to microorganisms of the activated sludge. The present study evaluates the effects of black liquor shocks in activated sludge systems. Four black liquor shocks from 883 to 3,225 mg chemical oxygen demand-COD L(-1) were applied during 24 hours in a continuously operating lab-scale activated sludge system. Removal efficiencies of COD, color and specific compounds were determined. Moreover, specific oxygen uptake rate (SOUR), sludge volumetric index (SVI) and indicator microorganisms were evaluated. Results show that the addition of black liquor caused an increase in COD removal (76-67%) immediately post shock; followed two days later by a decrease (-19-50%). On the other hand, SOUR ranged between 0.152 and 0.336 mgO2 g(-1) volatile suspended solids-VSS• min(-1) during shocks, but the initial value was reestablished at hour 24. When the COD concentration of the shock was higher than 1,014 mg/L, the abundance of stalked ciliates and rotifers dropped. Finally, no changes in SVI were observed, with values remaining in the range 65.8-40.2 mL g(-1) total suspended solids-TSS during the entire operating process. Based on the results, the principal conclusion is that the activated sludge system with the biomass adapted to the kraft pulp effluent could resist a black liquor shock with 3,225 mgCOD L(-1) of concentration during 24 h, under this study's conditions.

  19. EFFECT OF LIGNIN CONTENT OF Eucalyptus globulus WOOD IN KRAFT PULPING PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Gabriel Valim Cardoso

    2011-03-01

    Full Text Available In this research, it was analyzed the lignin content effect of Eucalyptus globulus wood in kraft pulping optimization. Seventy-two laboratory cooking were made with wood chips obtained from six Eucalyptus globulus trees selected from a group of 50 trees. The wood chips from three trees with the lowest lignin content, with average 20,53%, were mixed proportionally based on the tree weights, obtaining the sample of low lignin content wood. The same was made to obtain the sample for wood chips with the highest lignin content, with average 23,02%. The two lignin levels were statistically different. The two wood samples had basic densities statistically not different. Using three maximum temperatures levels (160, 165 and 170ºC, and three active alkali charged (17, 18,5 and 20%, the wood chips were converted to kraft pulps. The pulps were then characterized to analyze the influence of the distinct treatments employed in the cooking on their properties. The effect of the cooking conditions was expressed by mathematical models in order to determine the optimum points for each of the evaluated properties. The optimization process indicated maximum temperature of 168ºC, and active alkali of 19%, for maximum kraft pulping yield to achieve kappa number 18; this result was for woods with low lignin content. For woods containing the high lignin content, the optimization showed maximum cooking temperature of 169ºC and active alkali of 19% for kappa number of 18. The average reduction of 2,49% in wood lignin content resulted a correspondent gain of 2,2% in the kraft yield (o.d. basis and a reduction on the active alkali charge of 1,2% (o.d. basis to achieve kappa numbers from 16 to 19, preserving pulp properties. If the option is to work with kappa number 19 instead of 16, the gain in kraft yield is approximately 2%. Therefore, when working with low lignin content wood and kappa number 19 instead of 16, a substantial gain of approximately 4,2% is obtained

  20. Papermaking Properties of Carpinus betulus with kraft, Soda and Soda-Urea Pulping Processes

    Directory of Open Access Journals (Sweden)

    Rasoul Darstan

    2013-06-01

    Full Text Available This research was carried out in order to comparatively investigate the hornbeam kraft, soda and soda-urea papermaking properties. The selected treatment in kraft process had an average yield of 44.43% and kappa number of 23.75. In soda process the selected treatment had an average yield of 38.75% and kappa number of 19.28. In soda-urea process, the selected treatments had an average yield of 39.85, 40.1, 40.5, 39.8 and 40.61 and kappa number of 21.21, 22.33, 22.66, 25.28 and 26.85. After refining the selected pulp to reach the freeness of 400±25 ml CSF, 60 g/m2 handsheets were made and physical, mechanical and optical properties were measured. Results showed that kraft pulps had higher yield and better refinability than soda and soda-urea pulps. Papers made from kraft process had higher strength properties than those made of soda and soda-urea process. With addition of urea, yield and kappa number of pulps increased. The highest improvement in tensile index, breaking length and tear index was achieved with addition of 3% urea and the highest improvement in burst index was achieved with adding 4% urea. Results of brightness measurements showed that papers from kraft and soda processes had the lowest and highest brightness degree respectively. With the addition of urea, brightness of papers decreased.

  1. Soda-anthraquinone, kraft and organosolv pulping of holm oak trimmings.

    Science.gov (United States)

    Alaejos, J; López, F; Eugenio, M E; Tapias, R

    2006-11-01

    The operating conditions for an organosolv (ethyleneglycol) and two alkaline (soda-anthraquinone and kraft) processes for obtaining cellulose pulp and paper from holm oak (Quercus ilex) wood trimmings were optimized. A range of variation for each process variable (viz. temperature, cooking time and soda or ethyleneglycol concentration) was established and a central composite experimental design involving three independent variables at three different variation levels was applied. The results obtained with the three cooking processes used were compared and those provided by the kraft process were found to be the best. Thus, the tensile index values it provided (5.9-16.3 N m/g) were 23.7% and 41.5% better than those obtained with the soda-AQ and ethyleneglycol processes, respectively. Also, the kraft process provided the best burst index, brightness and kappa number values. Based on the optimum working ranges, the temperature and cooking time were the variables resulting in the most and least marked changes, respectively, in pulp properties.

  2. A multi-criteria decision analysis of management alternatives for anaerobically digested kraft pulp mill sludge.

    Directory of Open Access Journals (Sweden)

    Martijn Eikelboom

    Full Text Available The Multi-Criteria Decision Analysis (MCDA procedure was used to compare waste management options for kraft pulp mill sludge following its anaerobic digestion. Anaerobic digestion of sludge is advantageous because it produces biogas that may be used to generate electricity, heat and biofuels. However, adequate management of the digested sludge is essential. Landfill disposal is a non-sustainable waste management alternative. Kraft pulp mill digested sludge applied to land may pose risks to the environment and public health if the sludge has not been properly treated. This study is aimed to compare several recycling alternatives for anaerobically digested sludge from kraft pulp mills: land application, landfill disposal, composting, incineration, pyrolysis/gasification, and biofuel production by algae. The MCDA procedure considered nine criteria into three domains to compare digested sludge recycling alternatives in a kraft pulp mill: environmental (CO2 emission, exposure to pathogens, risk of pollution, material and energy recovery, economic (overall costs, value of products and technical (maintenance and operation, feasibility of implementation. The most suitable management options for digested sludge from kraft pulp mills were found to be composting and incineration (when the latter was coupled with recycling ash to the cement industry. Landfill disposal was the worst option, presenting low performance in feasibility of implementation, risk of pollution, material and energy recovery.

  3. A multi-criteria decision analysis of management alternatives for anaerobically digested kraft pulp mill sludge

    Science.gov (United States)

    Eikelboom, Martijn; Lopes, Alice do Carmo Precci; Silva, Claudio Mudadu; Rodrigues, Fábio de Ávila; Zanuncio, José Cola

    2018-01-01

    The Multi-Criteria Decision Analysis (MCDA) procedure was used to compare waste management options for kraft pulp mill sludge following its anaerobic digestion. Anaerobic digestion of sludge is advantageous because it produces biogas that may be used to generate electricity, heat and biofuels. However, adequate management of the digested sludge is essential. Landfill disposal is a non-sustainable waste management alternative. Kraft pulp mill digested sludge applied to land may pose risks to the environment and public health if the sludge has not been properly treated. This study is aimed to compare several recycling alternatives for anaerobically digested sludge from kraft pulp mills: land application, landfill disposal, composting, incineration, pyrolysis/gasification, and biofuel production by algae. The MCDA procedure considered nine criteria into three domains to compare digested sludge recycling alternatives in a kraft pulp mill: environmental (CO2 emission, exposure to pathogens, risk of pollution, material and energy recovery), economic (overall costs, value of products) and technical (maintenance and operation, feasibility of implementation). The most suitable management options for digested sludge from kraft pulp mills were found to be composting and incineration (when the latter was coupled with recycling ash to the cement industry). Landfill disposal was the worst option, presenting low performance in feasibility of implementation, risk of pollution, material and energy recovery. PMID:29298296

  4. In vitro penetration of bleaching agents into the pulp chamber

    DEFF Research Database (Denmark)

    Benetti, Ana Raquel; Valera, M C; Mancini, M N G

    2004-01-01

    To investigate pulp chamber penetration of bleaching agents in teeth following restorative procedures.......To investigate pulp chamber penetration of bleaching agents in teeth following restorative procedures....

  5. Yield-increasing additives in kraft pulping: Effect on carbohydrate retention, composition and handsheet properties

    Energy Technology Data Exchange (ETDEWEB)

    Vaaler, David Andre Grimsoeen

    2008-07-01

    In this thesis, increased hemicellulose retention during kraft pulping has been studied. The work has been divided into three parts: i) Development of an accessible and reliable method for determination of carbohydrate composition of kraft pulps ii) Investigation of the composition and molecular mass distributions of the carbohydrates in kraft pulps with increased hemicellulose content iii) Investigation of the effect of increased hemicellulose content on the sheet properties of kraft pulps with increased hemicellulose content. A method for carbohydrate determination was developed. In this method, enzymes are used to hydrolyse the pulp into monosaccharides. A relatively mild acid hydrolysis is performed prior to detection on an HPLC with an RI-detector. The pulp is not derivatized and no pre-treatment (mechanical or chemical) is needed to determine the carbohydrate composition using the method developed here. Peak deconvolution software is used to improve the accuracy. Polysulphide and H2S primarily increase the glucomannan yield, which can be boosted by up to 7 % on o.d. wood. However, the cellulose yield is more affected by the cooking time and the maximum yield increase of cellulose is approximately 2 % on o.d. wood compared to an ordinary kraft pulp. The cooking time is influenced by sulphide ion concentration, AQ addition and the final Kappa number. The xylan yield is remarkably stable, however the alkali profile during the cook may influence the xylan yield. Surface xylan content of the fibres depends on residual alkali concentration in the black liquor. The molecular mass distributions of cellulose and hemicellulose were determined for pulps with increased hemicellulose content using size exclusion chromatography. Deconvolution by peak separation software is used to gain information about the degree of polymerization for cellulose and hemicellulose. The average DP of glucomannan in the kraft fibre was found to be 350 +- 30 and the average DP of xylan in the

  6. Application of Alkaline Ionic Liquids in the Pretreatment Process of Eucalyptus Kraft Pulping

    Directory of Open Access Journals (Sweden)

    Yi Hou

    2016-09-01

    Full Text Available In order to explore the potential application of green solvent ionic liquids (ILs in the kraft pulping process, eucalyptus wood was pretreated by [Mmim]DMP before normal pulping. The results showed that materials pretreated shortly by the ionic liquid had a higher yield and viscosity coupled with a lower potassium permanganate value and residual lignin content in the pulp, as a result of the cooking process. It was also inferred that alkaline [Mmim]DMP pretreatment could dissolve lignin effectively from fiber to result in a stronger binding force and more entangled properties. Paper tensile and burst strength were improved by about 40% and 60%, respectively. These results provide a new way for eucalyptus to be utilized in the kraft pulping process.

  7. 40 CFR 63.443 - Standards for the pulping system at kraft, soda, and semi-chemical processes.

    Science.gov (United States)

    2010-07-01

    ... Paper Industry § 63.443 Standards for the pulping system at kraft, soda, and semi-chemical processes. (a... operator of each pulping system using a semi-chemical or soda process subject to the requirements of this... kraft, soda, and semi-chemical processes. 63.443 Section 63.443 Protection of Environment ENVIRONMENTAL...

  8. An approach to industrial application: influence of black liquor and pH on xylanase efficiency in bleaching of eucalyptus kraft pulp

    OpenAIRE

    Fillat Latorre, Úrsula; Roncero Vivero, María Blanca; Bassa, Alexandre; Sacón, Vera Maria

    2010-01-01

    To obtain a more realistic appraisal of the potential efficiency of xylanases in the industrial bleaching, the influence of pH and the presence of black liquor (measured as COD) on the bleaching efficiency of two commercial xylanases was studied at high temperature. These pH’s, CODs, and temperatures are close to those used in the storage tower of the B fiber line in Jacareı´ unit of Fibria (Brazil). The pulp samples obtained after each bleaching stage were analyzed for kappa number, brigh...

  9. Clean Bleaching Engineering Practice for Bagasse Pulp: Totally Chlorine-Free and Elemental Chlorine-Free Bleaching Realized with the Same Production Line

    Directory of Open Access Journals (Sweden)

    Zhi Li

    2015-03-01

    Full Text Available The experimental research, process design principles, and engineering practice of a bagasse pulp production line that could run both totally chlorine-free (OPQ(PO and elemental chlorine-free (OPD(EOP bleaching sequences are discussed in this paper. Under specified process conditions, the oxygen delignification rate was up to 50% and the brightness of unbleached pulp increased. The (OPQ(PO sequence bleached pulp had a brightness of 83.1% ISO and an intrinsic viscosity of 888 mL/g, and the (OPD(EOP sequence bleached pulp had a brightness of 85.7% ISO and an intrinsic viscosity of 905 mL/g. Pulp quality produced from both bleaching sequences was better than pulp bleached by the chlorination, alkaline extraction, and hypochlorite (CEH sequence. The wastewater was discharged only from the Q or D stage, and the chemical oxygen demand (COD of Q or D stage was about 650 mg/L or 1100 mg/L, respectively. It was easy to alternate between these two bleaching sequences, and the bleached pulp quality from these sequences was stable.

  10. An environmental systems analysis of the Kraft pulp industry in Thailand

    NARCIS (Netherlands)

    Warit, J.

    2006-01-01

    The pulp industry inThailandis of economic and social importance because of its production value, the revenues from export and the employment in this sector. The eucalyptus-based Kraft pulp industry plays an

  11. Alternative Technologies for Biofuels Production in Kraft Pulp Mills—Potential and Prospects

    Directory of Open Access Journals (Sweden)

    Esa Vakkilainen

    2012-07-01

    Full Text Available The current global conditions provide the pulp mill new opportunities beyond the traditional production of cellulose. Due to stricter environmental regulations, volatility of oil price, energy policies and also the global competitiveness, the challenges for the pulp industry are many. They range from replacing fossil fuels with renewable energy sources to the export of biofuels, chemicals and biomaterials through the implementation of biorefineries. In spite of the enhanced maturity of various bio and thermo-chemical conversion processes, the economic viability becomes an impediment when considering the effective implementation on an industrial scale. In the case of kraft pulp mills, favorable conditions for biofuels production can be created due to the availability of wood residues and generation of black liquor. The objective of this article is to give an overview of the technologies related to the production of alternative biofuels in the kraft pulp mills and discuss their potential and prospects in the present and future scenario.

  12. PROCESS FOR THE PRODUCTION OF DISSOLVING PULP FROM TREMA ORIENTALIS (NALITA) BY PREHYDROLYSIS KRAFT AND SODA-ETHYLENEDIAMINE (EDA) PROCESS

    OpenAIRE

    M. A. Quaiyyum; A. Noori; Labooni Ahsan; M. Sarwar Jahan

    2008-01-01

    This paper presents a preliminary study for the production of dissolving pulp from Trema orientalis (Nalita). Water prehydrolysis kraft and soda-ethylenediamine (EDA) pulping for the production of dissolving pulp from T. orientalis was investigated. Prehydrolysis at 150 and 170 oC did not produce pulp with high α-cellulose content when using the kraft process. But addition of 0.25 % H2SO4 in prehydrolysis liquor increased the purity of the pulp with the sacrifice of pulp yield and viscosity. ...

  13. Improvement in rice straw pulp bleaching effluent quality by incorporating oxygen delignification stage prior to elemental chlorine-free bleaching.

    Science.gov (United States)

    Kaur, Daljeet; Bhardwaj, Nishi K; Lohchab, Rajesh Kumar

    2017-10-01

    Environmental degradation by industrial and other developmental activities is alarming for imperative environmental management by process advancements of production. Pulp and paper mills are now focusing on using nonwood-based raw materials to protect forest resources. In present study, rice straw was utilized for pulp production as it is easily and abundantly available as well as rich in carbohydrates (cellulose and hemicelluloses). Soda-anthraquinone method was used for pulp production as it is widely accepted for agro residues. Bleaching process during paper production is the chief source of wastewater generation. The chlorophenolic compounds generated during bleaching are highly toxic, mutagenic, and bioaccumulative in nature. The objectives of study were to use oxygen delignification (ODL) stage prior to elemental chlorine-free (ECF) bleaching to reduce wastewater load and to study its impact on bleached pulp characteristics. ODL stage prior to ECF bleaching improved the optical properties of pulp in comparison to only ECF bleaching. When ODL stage was incorporated prior to bleaching, the tensile index and folding endurance of the pulp were found to be 56.6 ± 1.5 Nm/g and 140, respectively, very high in comparison to ECF alone. A potential reduction of 51, 57, 43, and 53% in BOD 3 , COD, color, and AOX, respectively was observed on adding the ODL stage compared to ECF only. Generation of chlorophenolic compounds was reduced significantly. Incorporation of ODL stage prior to bleaching was found to be highly promising for reducing the toxicity of bleaching effluents and may lead to better management of nearby water resources. Graphical abstract ᅟ.

  14. Process parameters affecting the delignification of eucalyptus kraft pulp with peroxyacetic acid

    Directory of Open Access Journals (Sweden)

    Chandranupap, P.

    2004-11-01

    Full Text Available Various process parameters affecting eucalyptus kraft pulp delignification with peroxyacetic acid were investigated. The results showed that pH was an important factor. The delignification rate increased with increasing pH to the value of 6. High delignification rate was obtained when the pulp was chelated with Na4-EDTA prior to the peroxyacetic acid stage. Therefore, delignification reaction rate depends on peroxyacid charge, temperature, pH and metal content of pulp.

  15. The number of bleaching sessions influences pulp tissue damage in rat teeth.

    Science.gov (United States)

    Cintra, Luciano Tavares Angelo; Benetti, Francine; da Silva Facundo, Aguinaldo Cândido; Ferreira, Luciana Louzada; Gomes-Filho, João Eduardo; Ervolino, Edilson; Rahal, Vanessa; Briso, André Luiz Fraga

    2013-12-01

    Hydrogen peroxide tooth bleaching is claimed to cause alterations in dental tissue structures. This study investigated the influence of the number of bleaching sessions on pulp tissue in rats. Male Wistar rats were studied in 5 groups (groups 1S-5S) of 10 each, which differed by the number (1-5) of bleaching sessions. In each session, the animals were anesthetized, and 35% hydrogen peroxide gel was applied to 3 upper right molars. Two days after the experimental period, the animals were killed, and their jaws were processed for light microscope evaluation. Pulp tissue reactions were scored as follows: 1, no or few inflammatory cells and no reaction; 2, session, necrotic tissue in the pulp horns and underlying inflammatory changes were observed. The extent and intensity of these changes increased with the number of bleaching sessions. After 5 sessions, the changes included necrotic areas in the pulp tissue involving the second third of the radicular pulp and intense inflammation in the apical third. The number of bleaching sessions directly influenced the extent of pulp damage. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  16. Application of thermoalkalophilic xylanase from Arthrobacter sp. MTCC 5214 in biobleaching of kraft pulp

    Digital Repository Service at National Institute of Oceanography (India)

    Khandeparker, R.; Bhosle, N.B.

    released by enzyme treatment showed a characteristic peak at 280 nm indicating the presence of lignin in the released coloring matter. Enzymatic prebleaching of kraft pulp showed 20 % reduction in kappa number of the pulp without much change in viscosity...

  17. Delignification of softwood kraft pulp by chlorine dioxide in a laboratory bleaching liquor displacement reactor

    International Nuclear Information System (INIS)

    Hamzeh, Y.; Izadyar, S.

    2008-01-01

    The chlorine dioxide delignification efficiency of softwood kraft pulp in the laboratory liquor displacement reactor (fixed bed reactor) was investigated and compared with conventional batch reactor. The comparison of two reactors was made based on the effective efficiency and overall efficiency of chlorine dioxide. Effective efficiency corresponds to the oxidizing capacity of chlorine dioxide which consumed by organic materials. Comparison of two reactors based on the effective efficiency showed that the selectivity of delignification significantly enhanced in the displacement reactor in which the primary reaction products are eliminated from reaction zone by displacing flow. On the other hand, the formation of high amounts of chlorate in the reaction zone of displacement reactor reduces the overall efficiency of chlorine dioxide delignification stage. Thus, in spite of significant decrease in useless secondary reactions, this type of reactor would not be cost effective in the industrial scale

  18. Measurement of cellulose content, Kraft pulp yield and basic density ...

    African Journals Online (AJOL)

    Previous descriptions of multisite and multispecies near infra-red (NIR) spectroscopic calibrations for predicting cellulose content (CC) and Kraft pulp yield (KPY) in eucalypt woodmeal demonstrated that large, single calibrations provide precise predictions for a wide range of sites and species. These have since been used ...

  19. Xylanase-Aided Chlorine Dioxide Bleaching of Bagasse Pulp to Reduce AOX Formation

    Directory of Open Access Journals (Sweden)

    Yi Dai

    2016-02-01

    Full Text Available Xylanase pretreatment was used to improve the chlorine dioxide bleaching of bagasse pulp. The pulp was pretreated with xylanase, which was followed by a chlorine dioxide bleaching stage. The HexA content of the pulp and the AOX content of the bleaching effluent were measured using UV-Vis and GC-MS methods, respectively. The results showed that a good correlation occurred between HexA and kappa number. HexA content of the pulp decreased significantly after the xylanase pretreatment. The AOX content of the bleaching effluent decreased as HexA was removed from the pulp. It was found that AOX could be reduced by up to 29.8%, comparing XD0 with a D0 stage. Fourier transform infrared spectroscopy (FTIR was employed to determine the breakage of chemical bonds in the pulp. It revealed that some lignin and hemicellulose were removed after xylanase treatment. The GC-MS results showed that some toxic chloride such as 2,4,6-trichlorophenol could be completely removed after xylanase pretreatment.

  20. The Use of Mg(OH2 in the Final Peroxide Bleaching Stage of Wheat Straw Pulp

    Directory of Open Access Journals (Sweden)

    Yan-Lan Liu

    2013-11-01

    Full Text Available Magnesium-based alkali is an attractive alkaline source for the peroxide bleaching of high-yield pulp. However, little information is available on Mg(OH2 application in the final peroxide bleaching stage of wheat straw pulp. The use of Mg(OH2 was demonstrated as a partial replacement for NaOH in the peroxide bleaching of a chelated oxygen-delignified wheat straw pulp. The yield, viscosity, and strength properties of bleached pulp significantly increased with increasing replacement ratio of Mg(OH2, while the chemical oxygen demand load (COD of filtrate was decreased. For similar brightness of bleached pulp at a 24% replacement ratio of Mg(OH2, the tensile and tear indices were higher, by 2.1 Nm.g-1 and 1.75 mN*m2.g-1, respectively, than that of control pulp bleached with NaOH as the sole alkaline source. When the MgSO4 was eliminated and the dosage of Na2SiO3 was decreased in the bleaching process, the tear and burst indices of the bleached pulp were also enhanced, with the brightness maintained. Scanning electron microscopy (SEM showed that more swelling occurred in the fibers of bleached pulp from the Mg(OH2-based bleaching process. Fiber analysis indicated that peroxide bleaching with Mg(OH2 increased the proportion of fiber lengths between 0.20 to 1.20 mm and 1.20 to 7.60 mm.

  1. Quality evaluation of dissolving pulp fabricated from banana plant stem and its potential for biorefinery.

    Science.gov (United States)

    Das, Atanu Kumar; Nakagawa-Izumi, Akiko; Ohi, Hiroshi

    2016-08-20

    The study was conducted to evaluate the quality of dissolving pulp of Musa sapientum L. (banana) plant stem and its potential for biorefinery. Introduction of pre-hydrolysis prior to any alkaline pulping process helps to reduce the content of hemicellulose and consequently produce acceptably high content of cellulose pulp. Water pre-hydrolysis was done at 150°C for 90min. The amount of lignin, xylan and glucan in the extracted pre-hydrolysis liquor (PHL) was 1.6, 4.9 and 1.6%, respectively. Pulping of pre-extracted chips was done following soda-AQ, alkaline sulfite and kraft process. The ratio of chip to liquor was 1:7 for both pre-hydrolysis and pulping. The kraft pulping process with 20% active alkali and 25% sulfidity at 150°C for 90min showed the best result. The lowest kappa number was 26.2 with a considerable pulp yield of 32.7%. The pulp was bleached by acidic NaClO2 and the consistency was 10% based on air-dried pulp. The lowest amount of 7% NaClO2 was used for the bleaching sequence of D0ED1ED2. After D0ED1ED2 bleaching, the pulp showed that α-cellulose, brightness and ash were 91.9, 77.9 and 1.6% respectively. The viscosity was 19.9cP. Hence, there is a possibility to use banana plant stem as a raw material for dissolving grade pulp and other bioproducts. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Yield Improvement and Energy Savings Uing Phosphonates as Additives in Kraft pulping

    Energy Technology Data Exchange (ETDEWEB)

    Ulrike W. Tschirner; Timothy Smith

    2007-03-31

    Project Objective: Develop a commercially viable modification to the Kraft process resulting in energy savings, increased yield and improved bleachability. Evaluate the feasibility of this technology across a spectrum of wood species used in North America. Develop detailed fundamental understanding of the mechanism by which phosphonates improve KAPPA number and yield. Evaluate the North American market potential for the use of phosphonates in the Kraft pulping process. Examine determinants of customer perceived value and explore organizational and operational factors influencing attitudes and behaviors. Provide an economic feasibility assessment for the supply chain, both suppliers (chemical supply companies) and buyers (Kraft mills). Provide background to most effectively transfer this new technology to commercial mills.

  3. Temperature variation in pulp chamber during dental bleaching in presence or absence of light activation

    OpenAIRE

    Mollica, Fernanda Brandão; Rocha, Daniel Maranha da; Travassos, Alessandro Caldas; Valera, Marcia Carneiro; Araujo, Maria Amélia Maximo de

    2010-01-01

    PURPOSE: In addition to the chemical damage due to bleaching gels penetration into the pulp during pulp vitality dental bleaching, another possible aggressive factor could be the heat generated by the exothermal oxidation reaction of the bleaching gel, which may also be aggravated by the use of light activation. This study assessed the temperature variation in the pulp chamber in human teeth, using three different bleaching gels with or without LED light activation. METHODS: Thirty human pre-...

  4. Producing a True Lignin Depolymerase for Biobleaching Softwood Kraft Pulp

    Energy Technology Data Exchange (ETDEWEB)

    Simo Sarkanen

    2002-02-04

    This project constituted an intensive effort devoted to producing, from the white-rot fungus Tramets Cingulata, a lignin degrading enzyme (lignin depolymerase) that is directly able to biobleach or delignify softwood kraft pulp brownstock. To this end, the solutions in which T. cingulata was grown contained dissolved kraft lignin which fulfilled two functions; it behaved as a lignin deploymerase substrate and it also appeared to act as an inducer of enzyme expression. However, the lignin depolymerase isoenzymes (and other extracellular T. cingulata enzymes) interacted very strongly with both the kraft lignin components and the fungal hypae, so the isolating these proteins from the culture solutions proved to be unexpectedly difficult. Even after extensive experimentation with a variety of protein purification techniques, only one approach appeared to be capable of purifying lignin depolymerases to homogeneity. Unfortunately the procedure was extremely laborious; it involved the iso electric focusing of concentrated buffer-exchanged culture solutions followed by electro-elution of the desired protein bands from the appropriate polyacrylamide gel segments

  5. STUDIES ON XYLANASE AND LACCASE ENZYMATIC PREBLEACHING TO REDUCE CHLORINE-BASED CHEMICALS DURING CEH AND ECF BLEACHING

    Directory of Open Access Journals (Sweden)

    Vasanta V. Thakur,

    2012-02-01

    Full Text Available The biobleaching efficiency of xylanase and laccase enzymes was studied on kraft pulps from wood and nonwood based raw materials employed in the Indian paper industry. Treatment of these pulps with xylanase enzyme could result in improved properties, showing 2.0% ISO gain in pulp brightness and/or reducing the demand of chlorine-based bleach chemicals by up to 15% with simultaneous reduction of 20 to 25% in AOX generation in bleach effluents. Further, mill-scale trial results revealed that enzymatic prebleaching can be successfully employed with xylanases to reach the same bleach boosting efficacy. Laccase bleaching was also studied on hardwood pulp at a pH around 8.0, where most of the pulp mills in India are operating, in contrast to earlier studies on laccase enzyme bleaching, which were conducted at acidic pHs, i.e. 4.0 to 5.0. In case of laccase bleaching, interesting results were found wherein a bleach-boosting effect was observed even at pH 8.0. Further studies carried out with HOBT as mediator in comparison to the commonly used and expensive ABTS laccase mediator system (LMS resulted in improvement of the bleaching efficiency with reduction in demand of chlorine dioxide by more than 35%. Potential for further reduction was indicated by the brightness gain, when compared with a control using the DE(pD bleach sequence.

  6. Mill Designed Bio bleaching Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Institute of Paper Science Technology

    2004-01-30

    A key finding of this research program was that Laccase Mediator Systems (LMS) treatments on high-kappa kraft could be successfully accomplished providing substantial delignification (i.e., > 50%) without detrimental impact on viscosity and significantly improved yield properties. The efficiency of the LMS was evident since most of the lignin from the pulp was removed in less than one hour at 45 degrees C. Of the mediators investigated, violuric acid was the most effective vis-a-vis delignification. A comparative study between oxygen delignification and violuric acid revealed that under relatively mild conditions, a single or a double LMS{sub VA} treatment is comparable to a single or a double O stage. Of great notability was the retention of end viscosity of LMS{sub VA} treated pulps with respect to the end viscosity of oxygen treated pulps. These pulps could then be bleached to full brightness values employing conventional ECF bleaching technologies and the final pulp physical properties were equal and/or better than those bleached in a conventional ECF manner employing an aggressively O or OO stage initially. Spectral analyses of residual lignins isolated after LMS treated high-kappa kraft pulps revealed that similar to HBT, VA and NHA preferentially attack phenolic lignin moieties. In addition, a substantial decrease in aliphatic hydroxyl groups was also noted, suggesting side chain oxidation. In all cases, an increase in carboxylic acid was observed. Of notable importance was the different selectivity of NHA, VA and HBT towards lignin functional groups, despite the common N-OH moiety. C-5 condensed phenolic lignin groups were overall resistant to an LMS{sub NHA, HBT} treatments but to a lesser extent to an LMS{sub VA}. The inactiveness of these condensed lignin moieties was not observed when low-kappa kraft pulps were biobleached, suggesting that the LMS chemistry is influenced by the extent of delignification. We have also demonstrated that the current

  7. Characterization of Cypress Wood for Kraft Pulp Production

    Directory of Open Access Journals (Sweden)

    António J. A. Santos

    2014-06-01

    Full Text Available Wood samples of Cupressus arizonica, C. lusitanica, and C. sempervirens were evaluated for chemical, anatomical, and pulp characteristics as raw material for pulp production. Two 17-year-old trees per species were harvested, and wood samples were taken at a height of 2 m. Wood chips from Pinus pinaster (Portugal and P. sylvestris (Finland were used as references. C. arizonica differed from C. lusitanica and C. sempervirens with significantly lower (p < 0.05 tracheid diameter and wall thickness in the earlywood. The total extractives contents were 3.9%, 3.3%, and 2.5% for C. lusitanica, C. sempervirens, and C. arizonica, respectively, lower than the 5.1% for P. pinaster and 4.5% for P. sylvestris. Klason lignin content ranged from 33.0 to 35.6%, higher than the 28.0 to 28.7% for the pinewoods. The kraft pulp yields for C. arizonica, C. lusitanica, and C. sempervirens were 37.7%, 36.7%, and 38.7%, respectively, with kappa numbers of 32.0, 31.6, and 28.7, respectively; the yield values were 40.8% and 42.8%, with kappa numbers of 23.4 and 21.0, for P. pinaster and P. sylvestris, respectively. The cypress species are clearly different from pine in relation to wood pulping behavior. Among the cypress, C. sempervirens provided the best pulping results.

  8. Simultaneous production of bio-ethanol and bleached pulp from red algae.

    Science.gov (United States)

    Yoon, Min Ho; Lee, Yoon Woo; Lee, Chun Han; Seo, Yung Bum

    2012-12-01

    The red algae, Gelidium corneum, was used to produce bleached pulp for papermaking and ethanol. Aqueous extracts obtained at 100-140 °C were subjected to saccharification, purification, fermentation, and distillation to produce ethanol. The solid remnants were bleached with chlorine dioxide and peroxide to make pulp. In the extraction process, sulfuric acid and sodium thiosulfate were added to increase the extract yield and to improve de-polymerization of the extracts, as well as to generate high-quality pulp. An extraction process incorporating 5% sodium thiosulfate by dry weight of the algae provided optimal production conditions for the production of both strong pulp and a high ethanol yield. These results suggest that it might be possible to utilize algae instead of trees and starch for pulp and ethanol production, respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Antioxidant capacity of Kraft black liquor from the pulp and paper industry.

    Science.gov (United States)

    Perez-Perez, Elizabeth; Rodríguez-Malaver, Antonio J

    2005-07-01

    The effect of Kraft black liquor on the lipid peroxidation of rat homogenates was examined. The lipid peroxidation of homogenates from different organs (kidney, brain, lung, and liver) was induced by Fenton's reagent. The products of lipid peroxidation, lipid hydroperoxides and TBARS were measured by FOX method and TBA assay, respectively. It was found that black liquor significantly reduced the concentration of TBARS, but not the concentration of lipid hydroperoxides. This inhibition was directly proportional to the concentration of Kraft black liquor and the incubation temperature. Conclusively, the black liquor from pulp and paper industry exhibited an antioxidant activity.

  10. Inter-laboratory comparisons of hexenuronic acid measurements in kraft eucalyptus pulps using a UV-Vis spectroscopic method

    Science.gov (United States)

    J.Y. Zhu; H.F Zhou; Chai X.S.; Donna Johannes; Richard Pope; Cristina Valls; M. Blanca Roncero

    2014-01-01

    An inter-laboratory comparison of a UV-Vis spectroscopic method (TAPPI T 282 om-13 “Hexeneuronic acid content of chemical pulp”) for hexeneuronic acid measurements was conducted using three eucalyptus kraft pulps. The pulp samples were produced in a laboratory at kappa numbers of approximately 14, 20, and 35. The hexeneuronic acid contents of the three pulps were...

  11. Utilización de Eucalyptus spp. Alternativas de plantaciones uruguayas para pulpa Kraft

    Directory of Open Access Journals (Sweden)

    Javier Doldán

    2011-05-01

    Full Text Available Las plantaciones de Eucalyptus globulus han mostrado desiguales tasas de crecimiento en diferentes regiones de Uruguay. Esto ha motivado la búsqueda de otros orígenes de semilla y especies para la producción de pulpa de celulosa. Propiedades papeleras de las pulpas blanqueadas (ECF de especies alternativas llevan a intuir que podrían ser atractivas para mercados de pulpa de fibra corta. En este trabajo se realiza un comparativo del E. grandis, E. dunnii, E. maidenii y E. globulus (procedencia de semilla “Jeeralang” con el E. globulus predominante en Uruguay. Se discute el potencial de estas maderas como base para una mezcla en cocción, basándose en el análisis de propiedades físicas (densidad aparente básica, propiedades pulpables (rendimiento, carga de álcali activo en cocción Kraft y consumo de madera y propiedades papeleras. En trabajos previos se han encontrado diferencias significativas entre el comportamiento pulpable del Eucalyptus globulus y Eucalyptus maidenii, sugiriendo que nosería recomendable mezclar estas especies. La misma conclusión se podría extender a las especies de Eucalyptus estudiadas. Sin embargo, teniendo en cuenta los similares requerimientos en las cargas de álcali activo, la mezcla entre especies alternativas podría ser aplicada.AbstractEucalyptus globulus plantations have shown different growth rates in different sites in Uruguay. This fact has triggered the search for other pulp wood species and seed provenance. Paper making properties of ECF bleached pulps of alternative speciessuggest that these species could be perfectly used as hardwood bleached pulp raw materials. This study intends to compare alternativeUruguayan pulpwood species E. grandis, E. dunnii, E. maidenii and “Jeeralang” a seed provenance of E. globulus to the E. globulus most widely cultivated in the country. Physical properties of wood (Basic Density, Kraft pulping performance (pulp yield, active alkali and wood consumption

  12. The effect of amphipilic lignin derivatives addition on enzymatic hydrolysis performance of kraft pulp from sorghum bagasse

    Science.gov (United States)

    Fatriasari, Widya; Nugroho Adi, D. T.; Laksana, R. P. B.; Fajriutami, T.; Raniya, R.; Ghozali, M.; Hermiati, E.

    2018-03-01

    Previously, the chemical characteristics of isolated lignin from Acacia mangium black liquor of kraft pulping was characterized. This lignin was blended with natural rubber latex (NR-L) as adhesive in laminated wood. In addition, lignin has potency for biosurfactant materials by modification of the hydrophobic into hydrophilic properties. Therefore, this study was intended to develop lignin as material for amphipilic lignin derivatives (A-LD) biosurfactant by reacting lignin with epoxilated polyethylene glicol (PEG). A-LD addition in slurries was used to improve the enzymatic hydrolysis (EH) of kraft pulp sweet bagasse sorghum (SSB). The main observation in EH performance was to investigate the effect of lignin isolation method (one and two step) in A-LD and A-LD loading addition on reducing sugar yield (RSY) of SSB kraft pulp. The pulp was hydrolyzed at 50°C and 150 rpm for 72 h with 10 FPU cellulase loading in the shaking incubator. A-LD from one (L1S) and two step (L2S) lignin was added with A-LD loading of 0, 1, 2, 5, and 10% (b/v). The RSY of hydrolyzate has been observed after EH. A-LDs addition in EH of SSB kraft pulp enhanced RSY. L1S worked better in reaction performance with PEDGE compared to L2S and LS. A better performance was showed by PEDGE 500 than that of PEDGE 6000. Generally, the higher A-LDs loading resulted higher RSY. The highest RSY (81.33%) was resulted in addition of 10% A-LD L1S using PEDGE 500. A 5% A-LD loading was more considered to be added in EH because the RSY was comparable with 10% A-LD loading.

  13. Alkaline Pulping and Bleaching of Acacia auriculiformis Grown in Bangladesh

    OpenAIRE

    JAHAN, M. Sarwar; SABINA, Rowshan; RUBAIYAT, Arjumand

    2014-01-01

    The physical, chemical, and morphological characteristics of Acacia auriculiformis were evaluated in terms of its suitability for papermaking. The fiber length (1.1 mm) of A. auriculiformis in this study was within the range of tropical hardwoods. The lignin content in A. auriculiformis was 19.4% and a-cellulose 44.1%, which was within the range of other acacias, but that of extractives was higher. Soda, soda-AQ, and kraft processes were studied in pulping. Screened pulp yield was increased w...

  14. CHEMICAL COMPOSITION, CRYSTALLINITY, AND THERMAL DEGRADATION OF BLEACHED AND UNBLEACHED KENAF BAST (Hibiscus cannabinus PULP AND NANOFIBERS

    Directory of Open Access Journals (Sweden)

    Mehdi Jonoobi

    2009-05-01

    Full Text Available Kenaf (Hibiscus cannabinus nanofibers were isolated from unbleached and bleached pulp by a combination of chemical and mechanical treatments. The chemical methods were based on NaOH-AQ (anthraquinone and three-stage bleaching (DEpD processes, whereas the mechanical techniques involved refining, cryo-crushing, and high-pressure homogenization. The size and morphology of the obtained fibers were characterized by environmental scanning electron microscopy (ESEM and transmission electron microscopy (TEM, and the studies showed that the isolated nanofibers from unbleached and bleached pulp had diameters between 10-90 nm, while their length was in the micrometer range. Fourier transform infrared (FTIR spectroscopy demonstrated that the content of lignin and hemicellulose decreased in the pulping process and that lignin was almost completely removed during bleaching. Moreover, thermogravimetric analysis (TGA indicated that both pulp types as well as the nanofibers displayed a superior thermal stability as compared to the raw kenaf. Finally, X-ray analyses showed that the chemo-mechanical treatments altered the crystallinity of the pulp and the nanofibers: the bleached pulp had a higher crystallinity than its unbleached counterpart, and the bleached nanofibers presented the highest crystallinity of all the investigated materials.

  15. Enzymatic pulp upgrade for producing high-value cellulose out of a Kraft paper pulp.

    Science.gov (United States)

    Hutterer, Christian; Kliba, Gerhard; Punz, Manuel; Fackler, Karin; Potthast, Antje

    2017-07-01

    The high-yield separation of polymeric parts from wood-derived lignocellulosic material is indispensable in biorefinery concepts. For the separation of cellulose and xylan from hardwood paper pulps to obtain pulps of high cellulose contents, simple alkaline extractions were found to be the most suitable technology, although having certain limitations. These are embodied by residual alkali resistant xylan incorporated in the pulp matrix. Further purification in order to produce pure cellulose with a low uniformity could be achieved selectively degrading residual xylan and depolymerizing the cellulose macromolecules by xylanase and cellulase. The latter help to adjust cellulose chain lengths for certain dissolving pulp grades while reducing the demand for ozone in subsequent TCF bleaching. Experiments applying different commercially available enzyme preparations revealed the dependency of xylanase performance on the residual xylan content in pulps being stimulated by additional cellulase usage. The action of the latter strongly depends on the cellulose allomorphy confirming the impact of the pulp morphology. Hence, the combined application of both types of enzymes offers a high potential for upgrading pulps in order to produce a pure and high-value cellulose product. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Solution blow spun nanocomposites of poly(lactic acid)/cellulose nanocrystals from Eucalyptus kraft pulp

    Science.gov (United States)

    Cellulose nanocrystals (CNCs) were extracted from Eucalyptus kraft pulp by sulfuric acid hydrolysis, and esterified with maleic anhydride (CNCMA). The incorporation of sulfate ester groups on the cellulose surface resulted in higher stability of the nanoparticles in aqueous suspensions and lower the...

  17. THE REACTIVITY OF PREHYDROLYZED SOFTWOOD KRAFT PULPS AFTER PROLONGED COOKING FOLLOWED BY CHLORITE DELIGNIFICATION

    OpenAIRE

    Ulf Germgard; Muhammad Asif Javed

    2011-01-01

    In a laboratory study high-quality spruce chips were prehydrolyzed to remove hemicelluloses and then kraft cooked to different kappa numbers by varying the cooking time. Each pulp sample was then chlorite delignified to selectively remove the remaining lignin. The reactivities of the pulp samples before and after chlorite delignification were determined by Fock’s test, which is supposed to measure the pulp’s reactivity in the conventional viscose process. A number of analyses were carried out...

  18. IMPACT OF FURFURAL ON THE SUGAR ANALYSIS OF PRE-HYDROLYSIS LIQUOR OF KRAFT-BASED DISSOLVING PULP PRODUCTION PROCESS USING THE HPAEC TECHNIQUE

    Directory of Open Access Journals (Sweden)

    Abrar Saeed

    2011-03-01

    Full Text Available High performance anion-exchange chromatography with pulse ampero-metric detector (HPAEC-PAD is a reliable method to systematically determine the sugar contents in pulp and paper waste streams, including bleaching and extraction liquors. We used the same method to determine the sugar content of industrially produced pre-hydrolysis liquor (PHL from a kraft-based dissolving pulp production process. The analysis showed that the traditional method cannot be applied for sugar analysis, and an improvement on the method was required. In fact, the presence of furfural in the PHL sample was the reason for the required modification. It was noted that the removal of furfural via evaporation could improve the reliability of the HPAEC technique for sugar assessments. If the concentration of furfural was higher than 0.045% (wt. in the PHL, the error introduced in the sugar analysis was profound. Also, the industrially produced PHL contained more furfural than the laboratory produced PHL under the same hydrolysis conditions. Consequently, the concentration of furfural in the PHL should be taken into account for sugar analysis using the HPAEC technique.

  19. Questioning Conventional Wisdom Regarding the Most Suitable Sequence of Enzyme Usage in Pulp Bleaching

    Directory of Open Access Journals (Sweden)

    Avdhesh Kumar Gangwar

    2015-11-01

    Full Text Available Increased public scrutiny and governmental legislation towards the pulp and paper industries have motivated industrialists and researchers to seek improved bleaching sequences having the potential to minimize pollutants in bleach effluent generated during manufacturing of paper. Discovery of toxic chlorinated organics and their components in bleach effluents has focused people’s attention towards finding alternative ways of bleaching pulp. Use of enzymes at industrial scale has become well known, but still it is not clear whether the sequence of enzymatic treatment most often employed in industrial applications represents the best overall practice. The point of enzyme addition is critically important to maximize benefits. Many publications describe the use of an enzyme treatment stage before the use of chemicals in a bleaching process. Insufficient attention has been paid to the alternatives of adding an enzyme in between chemical bleaching agents (intermediate or at the end of the bleaching process.

  20. OZONE BLEACHING AT NEUTRAL PH – A NEW CONCEPT

    Directory of Open Access Journals (Sweden)

    Fernando de Carvalho

    2010-08-01

    Full Text Available The effect of medium consistency ozone stage pH was evaluated for brown and oxygen delignified eucalyptus kraft pulp samples obtained from VCP - Luiz Antônio pulp mill. These samples were used as such or previously treated with the hot acid stage (A. The main objective of this study was to determine the viability of increasing the ozone stage pH aiming at decreasing bleaching variable costs. The ozone stage was studied in the pH range of 2.5-9.0, taking into account some important variables which affect ozone bleaching: (1 pulp kappa number entering the ozone stage, (2 reactivity of ozone towards lignin versus hexenuronic acids (HexA´s, (3 pulp treatments prior to ozone stage (acid hydrolysis, and (4 pulp treatments after the ozone stage (extraction or a chlorine dioxide stage.  Therefore, the impact of ozone stage pH was investigated in bleaching process such as Z/DEop vs AZ/DEop, Z/DEopD vs AZ/DEopD, Z/E vs AZ/E. The results were interpreted based on ozone stage efficiency and selectivity, and overall bleaching performance measured by the total bleaching chemical consumption required to achieve full brightness, pulp quality and environmental impact. It was concluded that the increase of ozone stage pH from 2.5 to 7.0 has a slightly negative impact on the efficiency and selectivity, measured after Z/DEop sequence, but this effect is not expressive in the end of Z/DEopD bleaching sequence. The increase of ozone stage pH from 2.5 to 7.0 in the sequence Z/DEopD is cost-effective at industrial level because it represents expressive reduction of sulphuric acid and caustic soda demand for pH control in the bleaching plant. These gain areas achieved without any significant changes in pulp quality and effluent load discharge. Nevertheless, the increase of ozone stage pH from 2.5 to 7.0 has a very high negative impact on the efficiency and selectivity for the Z/E and AZ/E processes and it is not recommended in such cases.

  1. 75 FR 35792 - Agency Information Collection Activities: Proposed Collection; Comment Request; Information...

    Science.gov (United States)

    2010-06-23

    ... production process units include operations such as pulping, bleaching, chemical recovery and papermaking. Different pulping processes are used, including chemical processes (kraft, soda, sulfite and semi-chemical... chemical pulp mills (kraft, sulfite, semi-chemical and soda wood pulping processes). For existing kraft and...

  2. Optimization of Laccase-Aided Chlorine Dioxide Bleaching of Bagasse Pulp

    Directory of Open Access Journals (Sweden)

    Yong Pei

    2015-11-01

    Full Text Available The laccase-mediator system in laccase-aided chlorine dioxide bleaching of bagasse pulp was optimized using response surface methodology (RSM. The effects and interactions of the laccase enzyme dosage, the dosage of the mediator 1-hydroxybenzotriazole (HBT, and the reaction time on the adsorbed organic halogen (AOX content of the wastewater as well as the brightness and kappa number of the pulp were examined. The optimal reaction conditions to achieve a balance of lower AOX content, higher brightness, and lower kappa number were as follows: laccase enzyme dosage of 20.3 U/g, HBT dosage of 1.51%, and reaction time of 154.5 min. Under these conditions, an AOX content of 20.67 mg/L, brightness of 58.94% ISO, and kappa number of 2.71 were observed. These results will offer a favorable option for pulp and paper mills as well as the natural environment and therefore provide a theoretical foundation for the industrial application of laccase in bleaching processes.

  3. Influence of different types of light on the response of the pulp tissue in dental bleaching: a systematic review.

    Science.gov (United States)

    Benetti, Francine; Lemos, Cleidiel Aparecido Araújo; de Oliveira Gallinari, Marjorie; Terayama, Amanda Miyuki; Briso, André Luiz Fraga; de Castilho Jacinto, Rogério; Sivieri-Araújo, Gustavo; Cintra, Luciano Tavares Angelo

    2018-05-01

    This systematic review (PROSPERO register: CRD42016053140) investigated the influence of different types of light on the pulp tissue during dental bleaching. Two independent authors conducted a systematic search and risk of bias evaluations. An electronic search was undertaken (PubMed/Medline, Embase, The Cochrane Library, and other databases) until May 2017. The population, intervention, comparison, outcomes (PICO) question was: "Does the light in dental bleaching change the response of the pulp to the bleaching procedure?" The intervention involved pulp tissue/cells after bleaching with light, while the comparison involved pulp tissue/cells after bleaching without light. The primary outcome was the inflammation/cytotoxicity observed in pulp after bleaching. Out of 2210 articles found, 12 articles were included in the review; four were in vivo studies (one study in dogs/others in human), and eight were in vitro studies (cell culture/with artificial pulp chamber or not). The light source used was halogen, light-emitting diode (LED), and laser. Only one in vivo study that used heat to simulate light effects showed significant pulp inflammation. Only two in vitro studies demonstrated that light influenced cell metabolism; one using halogen light indicated negative effects, and the other using laser therapy indicated positive effects. Given that animal and in vitro studies have been identified, there remain some limitations for extrapolation to the human situation. Furthermore, different light parameters were used. The effects of dental bleaching on the pulp are not influenced by different types of light, but different light parameters can influence these properties. There is insufficient evidence about the influence of different types of light on inflammation/cytotoxicity of the pulp.

  4. Fractionation and cellulase treatment for enhancing the properties of kraft-based dissolving pulp.

    Science.gov (United States)

    Duan, Chao; Wang, Xinqi; Zhang, YanLing; Xu, Yongjian; Ni, Yonghao

    2017-01-01

    The aim of this study was to investigate a combined process involving pulp fractionation and cellulase treatment of each fraction for improving the molecular weight distribution (MWD) and reactivity of a kraft-based dissolving pulp. Three pulp fractions, namely long-fiber, mid-fiber and short-fiber fractions (LF, MF and SF, respectively), were used as the substrates. The results showed that the SF had the highest accessibility, lowest viscosity, and highest cellulase adsorption capacity, while the opposite was true for the LF. At a given viscosity, the combined process led to a lower polydispersity index (3.71 vs 4.98) and a higher Fock reactivity (85.6% vs 76.3%), in comparison to the conventional single-stage cellulase treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Characterization of solid wastes from kraft pulp industry for ceramic materials development purposes

    International Nuclear Information System (INIS)

    Rodrigues, L.R.; Francisco, M.A.C.O.; Sagrillo, V.P.D.; Louzada, D.M.; Entringer, J.M.S.

    2016-01-01

    The Kraft pulp industry generates a large amount of solid wastes. Due this large quantity, the target of this study is characterize inorganic solid wastes, dregs, grits and lime mud, from the step of reagents recovery of Kraft process, aiming evaluate the potentiality of their use as alternative raw material on development of ceramic materials. Initially, the wastes were dried and ground, then they were subjected to the following characterization techniques: pH analysis, particle size analysis, X ray fluorescence, X ray diffraction, differential thermal analysis and thermogravimetric analysis and scanning electron microscopy. According to the results, it may be concluded that these wastes could be used as raw material in production of red ceramic and luting materials. (author)

  6. Microfibrillated cellulose from bamboo pulp and its properties

    International Nuclear Information System (INIS)

    Zhang, Junhua; Song, Hainong; Lin, Lu; Zhuang, Junping; Pang, Chunsheng; Liu, Shijie

    2012-01-01

    Microfibrillated cellulose (MFC) was obtained by disintegrating bleached kraft bamboo (Phyllostachys pubescens) pulp with a procedure of chemical pretreatment and high-pressure homogenization. The influences of sodium hydroxide dosage and homogenization times were evaluated by water retention value (WRV) of MFC. The properties, such as the surface morphology, rheological property and carboxyl acid content of MFC were also characterized using scanning electron microscope (SEM), rheometer and headspace gas chromatography (HS-GC) separately.

  7. Use of perborate in the bleaching of ethanolamine pulp from olive wood

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, E.; Torre, M.J. de la; Gutiérrez, J.C.

    2016-11-01

    In this work, we studied the influence of the bleacher concentration(2.5-5.5%), temperature (60-80 ºC) and time (60-180 min) on the reagent (perborate) consumption by dry pulp, various properties of the bleached pulp (yield, kappa number, brightness and viscosity/kappa numberratio), and some physical properties of paper sheets obtainedfrom it (tear index, burst index, stretch and breakinglength). The pulp was previously obtained by ethanolamine-soda-anthraquinone cooking of olive wood. A face-centred composite factor design was used to derive equations relating the pulp properties to the operational variables with a view to identifying the optimum operating conditions. The equations thus obtained reproduced the experimental results with errors less than 10% in all cases.The most suitable operating conditions were found to be alow temperature (60 ºC), a long time (180 min) and a highperborate concentration (5,5%). Because the pulp brightness achieved never exceeded 63% -not even under themost drastic conditions-, the process should not be used with one-step bleaching sequences. (Author)

  8. Use of perborate in the bleaching of ethanolamine pulp from olive wood

    International Nuclear Information System (INIS)

    Ramos, E.; Torre, M.J. de la; Gutiérrez, J.C.

    2016-01-01

    In this work, we studied the influence of the bleacher concentration(2.5-5.5%), temperature (60-80 ºC) and time (60-180 min) on the reagent (perborate) consumption by dry pulp, various properties of the bleached pulp (yield, kappa number, brightness and viscosity/kappa numberratio), and some physical properties of paper sheets obtainedfrom it (tear index, burst index, stretch and breakinglength). The pulp was previously obtained by ethanolamine-soda-anthraquinone cooking of olive wood. A face-centred composite factor design was used to derive equations relating the pulp properties to the operational variables with a view to identifying the optimum operating conditions. The equations thus obtained reproduced the experimental results with errors less than 10% in all cases.The most suitable operating conditions were found to be alow temperature (60 ºC), a long time (180 min) and a highperborate concentration (5,5%). Because the pulp brightness achieved never exceeded 63% -not even under themost drastic conditions-, the process should not be used with one-step bleaching sequences. (Author)

  9. Natural and recombinant fungal laccases for paper pulp bleaching

    NARCIS (Netherlands)

    Sigoillot, C.; Record, E.; Belle, V.; Robert, J.L.; Levasseur, A.; Punt, P.J.; Hondel, C.A.M.J.J. van den; Fournel, A.; Sigoillot, J.C.; Asther, M.

    2004-01-01

    Three laccases, a natural form and two recombinant forms obtained from two different expression hosts, were characterized and compared for paper pulp bleaching. Laccase from Pycnoporus cinnabarinus, a well known lignolytic fungus, was selected as a reference for this study. The corresponding

  10. Ecotoxicological studies with newly hatched larvae of Concholepas concholepas (Mollusca, Gastropoda): bioassay with secondary-treated kraft pulp mill effluents.

    Science.gov (United States)

    Manríquez, Patricio H; Llanos-Rivera, Alejandra; Galaz, Sylvana; Camaño, Andrés

    2013-12-01

    The Chilean abalone or "loco" (Concholepas concholepas, Bruguière 1789) represent the most economically important marine recourse exploited from inner inshore Management and Exploitation Areas for Benthic Resources along the Chilean coast. In this study, newly-hatched larvae of C. concholepas were investigated as a potential model species for marine ecotoxicological studies. The study developed a behavioral standard protocol for assessing the impact that kraft pulp mill effluents after secondary treatment have on C. concholepas larvae. Under controlled laboratory conditions, newly-hatched larvae were exposed to a series of different concentrations of kraft pulp mill effluents with secondary treatment (Pinus spp. and Eucalyptus spp.), potassium dichromate as standard reference toxicant and effluent-free control conditions. Regardless of the type of effluent the results indicated that diluted kraft pulp effluent with secondary treatment had reduced effect on larval survival. Low larval survivals were only recorded when they were exposed to high concentrations of the reference toxicant. This suggests that C. concholepas larval bioassay is a simple method for monitoring the effects of kraft pulp mill effluents with secondary treatment discharged into the sea. The results indicated that dilution of ca. 1% of the effluent with an elemental chlorine free (ECF) secondary treatment is appropriate for achieving low larval mortalities, such as those obtained under control conditions with filtered seawater, and to minimize their impact on early ontogenetic stages of marine invertebrates such as newly-hatched larvae of C. concholepas. The methodological aspects of toxicological testing and behavioral responses described here with newly-hatched larvae of C. concholepas can be used to evaluate in the future the potential effects of other stressful conditions as other pollutants or changes in seawater pH associated with ocean acidification. © 2013 Elsevier Inc. All rights

  11. Lipophilic extractives from several nonwoody lignocellulosic crops (flax, hemp, sisal, abaca) and their fate during alkaline pulping and TCF/ECF bleaching.

    Science.gov (United States)

    Marques, Gisela; del Río, José C; Gutiérrez, Ana

    2010-01-01

    The fate of lipophilic extractives from several nonwoody species (flax, hemp, sisal and abaca) used for the manufacturing of cellulose pulps, was studied during soda/anthraquinone (AQ) pulping and totally chorine free (TCF) and elemental chlorine free (ECF) bleaching. With this purpose, the lipophilic extracts from the raw materials and their unbleached and bleached industrial pulps, were analyzed by gas chromatography-mass spectrometry. Aldehydes, hydroxyfatty acids and esterified compounds such as ester waxes, sterol esters and alkylferulates strongly decreased after soda/AQ pulping while alkanes, alcohols, free sterols and sterol glycosides survived the cooking process. Among the lipophilic extractives that remained in the unbleached pulps, some amounts of free sterols were still present in the TCF pulps whereas they were practically absent in the ECF pulps. Sterol glycosides were also removed after both TCF and ECF bleaching. By contrast, saturated fatty acids, fatty alcohols and alkanes were still present in both bleached pulps.

  12. A primary estimation of PCDD/Fs release reduction from non-wood pulp and paper industry in China based on the investigation of pulp bleaching with chlorine converting to chlorine dioxide.

    Science.gov (United States)

    Xiao, Qingcong; Song, Xiaoqian; Li, Wenchao; Zhang, Yuanna; Wang, Hongchen

    2017-10-01

    Chlorine bleaching technology (C process, CEH process, H process and theirs combination), which was identified as a primary formation source of PCDD/Fs, is still widely used by the vast majority of Chinese non-wood pulp and paper mills (non-wood PMs). The purpose of this study was to provide information and data support for further eliminating dioxin for non-wood PMs in China, and especially to evaluate the PCDD/Fs release reduction for those mills converting their pulp bleaching processes from CEH to ECF. The PCDD/Fs concentrations of the bleached pulp and bleaching wastewater with ECF bleaching were in the ranges of 0.13-0.8 ng TEQ kg -1 , and 0.15-1.9 pg TEQ L -1 , respectively, which were far lower than those with CEH process, indicating that the ECF process is an effective alternative bleaching technology to replace CEH in Chinese non-wood PMs to reduce dioxin release. The release factor via flue gas of the alkali recovery boiler in Chinese non-wood PMs was first reported to be 0.092 μg TEQ Ad t -1 in this study. On the assumption that pulp bleaching processes of all Chinese non-wood PMs were converted from CEH to ECF, the annual release of PCDD/Fs via the bleaching wastewater and bleached pulp would be reduced by 79.1%, with a total of 1.60 g TEQ. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Influence of whitening gel on pulp chamber temperature rise by in-office bleaching technique

    Directory of Open Access Journals (Sweden)

    Sandro Cordeiro Loretto

    Full Text Available INTRODUCTION: Dental bleaching is a conservative method for the aesthetic restoration of stained teeth. However, whitening treatments are likely to cause adverse effects when not well planned and executed. OBJECTIVE: This study evaluated the influence of whitening gel on temperature rise in the pulp chamber, using the in-office photoactivated dental bleaching technique. MATERIAL AND METHOD: The root portion of an upper central human incisor was sectioned 3mm below the cemento-enamel junction. The root canal was enlarged to permit the insertion of the K-type thermocouple sensor (MT-401 into the pulp chamber, which was filled with thermal paste to facilitate the transfer of heat during bleaching. Three photosensitive whitening agents (35% hydrogen peroxide were used: Whiteness HP (FGM, Whiteness HP Maxx (FGM and Lase Peroxide Sensy (DMC. An LED photocuring light (Flash Lite - Discus Dental was used to activate the whitening gels. Six bleaching cycles were performed on each group tested. The results were submitted to one-way ANOVA and LSD t-test (α<0.05. RESULT: The lowest mean temperature variation (ºC was detected for Lase Peroxide Sensy (0.20, while the highest was recorded for Whiteness HP (1.50. CONCLUSION: The Whiteness HP and Whiteness HP Maxx whitening gels significantly affected the temperature rise in the pulp chamber during bleaching, and this variation was dependent on the type of whitening gel used.

  14. Process integration study of a kraft pulp mill converted to an ethanol production plant – part B: Techno-economic analysis

    International Nuclear Information System (INIS)

    Fornell, Rickard; Berntsson, Thore; Åsblad, Anders

    2012-01-01

    In a previous study by the authors, energy efficiency measures in a conceptual kraft pulp mill converted to a lignocellulosic ethanol plant were investigated. The results suggested a number of different process designs which would give a substantial improvement in steam economy in the ethanol plant, compared to the original design. In the present study the different process designs are evaluated from an economic point-of-view, in order to determine if energy efficiency measures and increasing by-product sales decrease the production cost of ethanol from this specific process, or if the increased costs related to the implementation of these measures overshadow the benefits from increased by-product sales. The different energy efficiency measures are compared with less capital demanding alternatives (i.e. including low or no energy efficiency improvements) in order to assess the economic benefits of different strategies when converting a kraft pulp mill to ethanol production. The study indicates the economic importance of considering energy efficiency measures when repurposing a kraft pulp mill to an ethanol plant. It is also shown that, within the context of this study, a larger investment in measures will give better economic results than less capital demanding alternatives (with less improvement in energy efficiency). From an economic and energy efficiency viewpoint many of the suggested process designs will give approximately similar results, therefore the process design should be made based on other criteria (e.g. low complexity, low maintenance). - Highlights: ► Conversion of a kraft pulp mill to ethanol production. ► Heat integration of distillation/evaporation in a lignocellulosic ethanol plant. ► Energy efficiency measures lead to lower ethanol production cost. ► If capital costs and raw material prices are low the production cost could be as low as 365 €/m 3 EtOH.

  15. Investigation of ESEM/EDX to measure liquor penetration and diffusion in Eucalyptus grandis wood chips during kraft pulping

    CSIR Research Space (South Africa)

    Grzeskowiak, V

    2011-01-01

    Full Text Available Environmental scanning electron microscopy coupled with energy dispersive x-ray (ESEM/EDX) was optimised to measure the penetration and diffusion of cooking liquor into Eucalyptus grandis wood chips during kraft pulping. The moisture content...

  16. 75 FR 76005 - Agency Information Collection Activities; Submission to OMB for Review and Approval; Comment...

    Science.gov (United States)

    2010-12-07

    ... production process units include operations such as pulping, bleaching, chemical recovery, and papermaking. Different pulping processes are used, including chemical processes (kraft, soda, sulfite, and semi-chemical... or paperboard products, including: mills that carry out chemical wood pulping (kraft, sulfite, soda...

  17. Kinetics of Adsorbable Organic Halides (AOX Reduction in Laccase-Aided Chlorine Dioxide Bleaching of Bagasse Pulp

    Directory of Open Access Journals (Sweden)

    Xueping Song

    2016-07-01

    Full Text Available This paper presents a kinetic model of the laccase-aided chlorine dioxide bleaching of bagasse pulp. The kinetic model was based on the rate of reduction of adsorbed organic halogen (AOX. The effects of the laccase enzyme dosage, the mediator 1-hydroxybenzotriazole (HBT dosage, and the reaction temperature on the AOX content of the bleaching effluent are discussed. Good fits were obtained for the experimental data obtained from the different laccase enzyme dosages, HBT dosages, and reaction temperatures, indicating the feasibility of the kinetic model as a means of predicting the optimal operation conditions for the laccase-aided chlorine dioxide bleaching of bagasse pulp in the future.

  18. Development of a combined piezoresistive pressure and temperature sensor using a chemical protective coating for Kraft pulp digester process monitoring

    International Nuclear Information System (INIS)

    Mohammadi, Abdolreza R; Chiao, Mu; Bennington, Chad P J

    2011-01-01

    We have developed an integrated piezoresistive pressure and temperature sensor for multiphase chemical reactors, primarily Kraft pulp digesters (pH 13.5, temperatures up to 175 °C, reaching a local maximum of 180 °C and pressures up to 2 MPa). The absolute piezoresistive pressure sensor consisted of a large square silicon diaphragm (1000 × 1000 µm 2 ) and high resistance piezoresistors (10 000 Ω). A 4500 Ω buried piezoresistive wire was patterned on the silicon chip to form a piezoresistive temperature sensor which was used for pressure sensor compensation and temperature measurement. A 4 µm thick Parylene HT® coating, a chemically resistant epoxy and a silicone conformal coating were deposited to passivate the pressure sensor against the caustic environment in Kraft digesters. The sensors were characterized up to 2 MPa and 180 °C in an environment chamber. A maximum thermal error of ±0.72% full-scale output (FSO), an average sensitivity of 0.116 mV (V kPa) −1 and a power consumption of 0.3 mW were measured in the pressure sensor. The sensors' resistances were measured before and after test in a Kraft pulping cycle and showed no change in their values. SEM pictures and topographical surfaces were also analyzed before and after pulp liquor exposure and showed no observable changes.

  19. Direct heat transfer considerations for improving energy efficiency in pulp and paper Kraft mills

    International Nuclear Information System (INIS)

    Savulescu, Luciana Elena; Alva-Argaez, Alberto

    2008-01-01

    The success of any process improvement study depends on the quality of the available data and the way in which the plant-specific characteristics are incorporated in the applied conceptual models; in the context of process integration studies these issues are directly related to the rules followed during the data extraction stage. Improving energy efficiency in a pulp and paper Kraft mill requires the identification of the most promising heat recovery network retrofit projects. In a retrofit analysis using pinch technology/process integration methods, only the process streams associated to the existing heat exchangers and some outlet streams (such as wastewater/effluent streams and vents) with high potential for heat recovery are usually included, while the energy exchanged through non-isothermal stream mixing (NIM) or direct heat transfer (DHT) is often assumed fixed and is not considered in the analysis. Relaxing this assumption requires extracting more data to represent the DHT design configuration that exists in the plant. However, different data extraction options can be considered to represent the DHT configuration depending on the associated process/operation constraints. This work describes a systematic procedure to extract and analyse the impacts of DHT on the overall energy efficiency of a Kraft process with a specific focus on mixing along the pulp line and in water tanks

  20. A Cost-Benefit Assessment of Gasification-Based Biorefining in the Kraft Pulp and Paper Industry

    Energy Technology Data Exchange (ETDEWEB)

    Eric D. Larson; Stefano Consonni; Ryan E. Katofsky; Kristiina Iisa; W. James Frederick

    2007-03-31

    Production of liquid fuels and chemicals via gasification of kraft black liquor and woody residues (''biorefining'') has the potential to provide significant economic returns for kraft pulp and paper mills replacing Tomlinson boilers beginning in the 2010-2015 timeframe. Commercialization of gasification technologies is anticipated in this period, and synthesis gas from gasifiers can be converted into liquid fuels using catalytic synthesis technologies that are in most cases already commercially established today in the ''gas-to-liquids'' industry. These conclusions are supported by detailed analysis carried out in a two-year project co-funded by the American Forest and Paper Association and the Biomass Program of the U.S. Department of Energy. This work assessed the energy, environment, and economic costs and benefits of biorefineries at kraft pulp and paper mills in the United States. Seven detailed biorefinery process designs were developed for a reference freesheet pulp/paper mill in the Southeastern U.S., together with the associated mass/energy balances, air emissions estimates, and capital investment requirements. Commercial (''Nth'') plant levels of technology performance and cost were assumed. The biorefineries provide chemical recovery services and co-produce process steam for the mill, some electricity, and one of three liquid fuels: a Fischer-Tropsch synthetic crude oil (which would be refined to vehicle fuels at existing petroleum refineries), dimethyl ether (a diesel engine fuel or LPG substitute), or an ethanol-rich mixed-alcohol product. Compared to installing a new Tomlinson power/recovery system, a biorefinery would require larger capital investment. However, because the biorefinery would have higher energy efficiencies, lower air emissions, and a more diverse product slate (including transportation fuel), the internal rates of return (IRR) on the incremental capital investments would be

  1. Anaerobic biodegradability and toxicity of wastewaters from chlorine and total chlorine-free bleaching of eucalyptus kraft pulps.

    NARCIS (Netherlands)

    Vidal, G.; Soto, M.; Field, J.; Mendez-Pampin, R.; Lema, J.M.

    1997-01-01

    Chlorine bleaching effluents are problematic for anaerobic wastewater treatment due to their high methanogenic toxicity and low biodegradability. Presently, alternative bleaching processes are being introduced, such as elemental chlorine-free (ECF) and total chlorine-free (TCF) bleaching. The

  2. Process integration study of a kraft pulp mill converted to an ethanol production plant – Part A: Potential for heat integration of thermal separation units

    International Nuclear Information System (INIS)

    Fornell, Rickard; Berntsson, Thore

    2012-01-01

    Energy efficiency is an important parameter for the profitability of biochemical ethanol production from lignocellulosic raw material. The yield of ethanol is generally low due to the limited amount of fermentable compounds in the raw material. Increasing energy efficiency leads to possibilities of exporting more by-products, which in turn might reduce the net production cost of ethanol. Energy efficiency is also an important issue when discussing the repurposing of kraft pulp mills to biorefineries, since the mills in question most likely will be old and inefficient. Investing in energy efficiency measures might therefore have a large effect on the economic performance. This paper discusses energy efficiency issues related to the repurposing of a kraft pulp mill into a lignocellulosic ethanol production plant. The studied process is a typical Scandinavian kraft pulp mill that has been converted to a biorefinery with ethanol as main product. A process integration study, using pinch analysis and process simulations, has been performed in order to assess alternative measures for improving the energy efficiency. The improvements found have also been related to the possibilities for by-product sales from the plant (electricity and/or lignin). In a forthcoming paper, which is the second part of this process integration study, an economic analysis based on the results from this paper will be presented. - Highlights: ► Conversion of a kraft pulp mill to ethanol production. ► Heat integration of distillation/evaporation in a lignocellulosic ethanol plant. ► Advanced pinch curves used to find new integration possibilities. ► 35–40% reduction of steam demand.

  3. EVALUATION OF LINERBOARD PROPERTIES FROM MALAYSIAN CULTIVATED KENAF SODA-ANTHRAQUINONE PULPS VERSUS COMMERCIAL PULPS

    OpenAIRE

    Ahmad Azizi Mossello; Jalaluddin Harun; Rushdan Ibrahim; Hossien Resalati; Seyed Rashid Fallah Shamsi; Paridah Md Tahir; Mohd Nor Mohad Yusoff

    2010-01-01

    Malaysian cultivated kenaf has been identified as a suitable raw material for linerboard production. This study examines the soda-antraquinone (soda-AQ) pulp of kenaf fibers versus old corrugated container (OCC) and unbleached softwood kraft pulps as the main sources for linerboard production. The results showed significant differences among the pulp properties. The unbleached kraft pulp with very high freeness required high beating to reach an optimized freeness and produced paper with the h...

  4. Direct heat transfer considerations for improving energy efficiency in pulp and paper Kraft mills

    Energy Technology Data Exchange (ETDEWEB)

    Savulescu, Luciana Elena; Alva-Argaez, Alberto [Natural Resources (Canada)

    2008-10-15

    The success of any process improvement study depends on the quality of the available data and the way in which the plant-specific characteristics are incorporated in the applied conceptual models; in the context of process integration studies these issues are directly related to the rules followed during the data extraction stage. Improving energy efficiency in a pulp and paper Kraft mill requires the identification of the most promising heat recovery network retrofit projects. In a retrofit analysis using pinch technology/process integration methods, only the process streams associated to the existing heat exchangers and some outlet streams (such as wastewater/effluent streams and vents) with high potential for heat recovery are usually included, while the energy exchanged through non-isothermal stream mixing (NIM) or direct heat transfer (DHT) is often assumed fixed and is not considered in the analysis. Relaxing this assumption requires extracting more data to represent the DHT design configuration that exists in the plant. However, different data extraction options can be considered to represent the DHT configuration depending on the associated process/operation constraints. This work describes a systematic procedure to extract and analyse the impacts of DHT on the overall energy efficiency of a Kraft process with a specific focus on mixing along the pulp line and in water tanks. (author)

  5. Structural Alterations of Lignins in Transgenic Poplars with Depressed Cinnamyl Alcohol Dehydrogenase or Caffeic Acid O-Methyltransferase Activity Have an Opposite Impact on the Efficiency of Industrial Kraft Pulping1

    Science.gov (United States)

    Lapierre, Catherine; Pollet, Brigitte; Petit-Conil, Michel; Toval, Gabriel; Romero, Javier; Pilate, Gilles; Leplé, Jean-Charles; Boerjan, Wout; Ferret, Valérie; De Nadai, Véronique; Jouanin, Lise

    1999-01-01

    We evaluated lignin profiles and pulping performances of 2-year-old transgenic poplar (Populus tremula × Populus alba) lines severely altered in the expression of caffeic acid/5-hydroxyferulic acid O-methyltransferase (COMT) or cinnamyl alcohol dehydrogenase (CAD). Transgenic poplars with CAD or COMT antisense constructs showed growth similar to control trees. CAD down-regulated poplars displayed a red coloration mainly in the outer xylem. A 90% lower COMT activity did not change lignin content but dramatically increased the frequency of guaiacyl units and resistant biphenyl linkages in lignin. This alteration severely lowered the efficiency of kraft pulping. The Klason lignin level of CAD-transformed poplars was slightly lower than that of the control. Whereas CAD down-regulation did not change the frequency of labile ether bonds or guaiacyl units in lignin, it increased the proportion of syringaldehyde and diarylpropane structures and, more importantly with regard to kraft pulping, of free phenolic groups in lignin. In the most depressed line, ASCAD21, a substantially higher content in free phenolic units facilitated lignin solubilization and fragmentation during kraft pulping. These results point the way to genetic modification of lignin structure to improve wood quality for the pulp industry. PMID:9880356

  6. Effects of bleaching agents and adhesive systems in dental pulp: a literature review

    OpenAIRE

    Oliveira, Maria Antonieta Veloso Carvalho de; Quagliatto, Paulo Sérgio; Magalhães, Denildo; Biffi, João Carlos Gabrielli

    2012-01-01

    The dental pulp may be exposed to several irritants that are potentially noxious to the health and functions of this tissue. Each type of irritant or injury has different effects on the pulp, which are generally characterized by acute inflammation, chronic inflammation or necrosis. Common examples of irritants are dental caries, cavity preparation procedures, traumatic injuries, and chemical substances like bleaching agents and adhesive systems. The present study aimed to review the current k...

  7. The Effects of Short Wave UV Irradiation (254-366nm on Color Values of Recycled and Bleached ONP/OMP Pulps

    Directory of Open Access Journals (Sweden)

    Emrah Peşman

    2011-04-01

    Full Text Available ABSTRACT As it is known, mechanical pulp papers include significant amount of lignin and carbohydrates as well as cellulose. Thus, when these lignin reach papers irradiated with short wave UV light they could not protect their color. In this study, bleaching of ONP/OMG recycled pulps with hydrogen peroxide, sodium percarbonate, sodium dithyonite, sodium borohydride and formamidin sulfunic acid were performed. Then the test papers of these pulps were irradiated with 254-366nm UV light and changes in the ISO Brightness, CIE L*a*b*, yellowness (YI and whiteness (WI values were observed. At the result of study, all bleaching agents were determined as insufficient in the respect of color stability. But if they compared with each other, the two stages sodium percarbonate-sodium borohydride bleaching sequence was gave the best results against to color reversion. Keywords: Old news/old magazine papers (ONP/OMG, Bleaching, Color Stability, UV Irradiation

  8. Evaluating pulp stiffness from fibre bundles by ultrasound

    Science.gov (United States)

    Karppinen, Timo; Montonen, Risto; Määttänen, Marjo; Ekman, Axel; Myllys, Markko; Timonen, Jussi; Hæggström, Edward

    2012-06-01

    A non-destructive ultrasonic tester was developed to measure the stiffness of pulp bundles. The mechanical properties of pulp are important when estimating the behaviour of paper under stress. Currently available pulp tests are tedious and alter the fibres structurally and mechanically. The developed tester employs (933 ± 15) kHz tweezer-like ultrasonic transducers and time-of-flight measurement through (9.0 ± 2.5) mm long and (0.8 ± 0.1) mm thick fibre bundles kept at (19.1 ± 0.4) °C and (62 ± 1)% RH. We determined the stiffness of soft wood pulps produced by three kraft pulping modifications: standard kraft pulp, (5.2 ± 0.4) GPa, prehydrolysis kraft pulp, (4.3 ± 0.4) GPa, and alkali extracted prehydrolysis kraft pulp, (3.3 ± 0.4) GPa. Prehydrolysis and alkali extraction processes mainly lowered the hemicellulose content of the pulps, which essentially decreased the fibre-wall stiffness hence impairing the stiffness of the fibre networks. Our results indicate that the method allows ranking of pulps according to their stiffness determined from bundle-like samples taken at an early phase of the papermaking process.

  9. MINERAL ELEMENTS IN WOODS OF EUCALYPTUS AND BLACK WATTLE AND ITS INFLUENCE IN A BLEACHED KRAFT PULP MILL

    Directory of Open Access Journals (Sweden)

    André Fredo

    2009-09-01

    Full Text Available Effluents are one of the most important problems in a pulp mill regarding to environmental subjects. With the purpose to reduce them, the mills are closing the internal cycles and reducing the water consumption. The wood, as the most significant source of non-process elements to the system, is responsible for some troubles to the industrial process. With the aim of evaluating their intake and to offer some informations for closing the loop, the contents of Al, Ca, Cu, Fe, K, Mg, Mn, Na, Ni, and Si were analysed in Acacia mearnsii, Eucalyptus dunnii, Eucalyptus globulus globulus, Eucalyptus grandis and Eucalyptus saligna woods. Wood samples were prepared by oven burning and acidic digestion methods, following analysis by ICP (inductively coupled plasm. Using also the results from silvicultural evaluation of trees and stands, they were calculated which elements were carried out from the site in larger amounts (K, Ca, Na, Al, Mn and Si and the species which exported largest amount of these elements (Eucalyptus dunnii and Eucalyptus globulus. The species with lower growth were Eucalyptus globulus and Eucalyptus dunnii, that leads to a bigger elements input and more potential industrial troubles. It was observed a range of 3.8 (Eucalyptus grandis up to 6 (Eucalyptus dunnii kg of analised mineral elements introduced to the process per ton of umbleached pulp produced. The Acacia mearnsii showed the lower level for Fe, Mn and Ni, being useful for oxygen, ozone and peroxide bleaching. The silicon observed in woods was in low concentration although the high values of this element in industrial liquor cycle. This leads to state that there is some contamination with soil when harvesting and handling the wood. Special care must be taken with both high ash and high mineral elements species, such as Eucalyptus dunnii and Eucalyptus globulus.

  10. Effect of raw wood supply system on the wood paying capability of a kraft pulp mill using Scots pine

    Energy Technology Data Exchange (ETDEWEB)

    Dahl, O. (Helsinki Univ. of Technology, Espoo (Finland), Dept. of Forest Products Technology), Email: olli.dahl@tkk.fi; Jylhae, P. (Finnish Forest Research Inst., Kannus (Finland)), Email: paula.jylha@metla.fi; Laitila, J. (Finnish Forest Research Inst., Joensuu (Finland)), Email: juha.laitila@metla.fi; Kaerhae, K. (Metsaeteho Oy, Helsinki (Finland)), Email: kalle.karha@metsateho.fi

    2009-07-01

    Integration of energy wood procurement into that of pulpwood is seen as a means for reducing the high procurement costs of small-diameter wood harvested from first thinnings. In the deepest mode of integration, pulp and energy fractions are separated from each other in the debarking drum of the pulp mill. In the present paper, the competitiveness of the conventional supply chain based on cut-to-length harvesting was compared to the supply systems based on the harvesting of loose whole trees and whole-tree bundling, in the cases of three Scots pine-dominated first-thinning stands using wood paying capability (WPC) of a kraft pulp mill as a decisive criterion. Furthermore, the competitiveness of first thinnings as raw material sources for a pulp mill was evaluated by using intermediate thinnings as s reference. (orig.)

  11. EFFECT OF THE REACTION CONDITIONS OVER THE YIELD AND PROPERTIES OF METHYLCELLULOSE OBTAINED FROM PINUS RADIATA KRAFT BLEACHED CELLULOSE

    OpenAIRE

    TAPIA, C.; SAPAG-HAGAR, J.; ANDRADE, C.T.; HASSÓN, J.; VALENZUELA, F.; BASUALTO, C.

    2002-01-01

    Kraft bleached cellulose from Pinus radiata was submitted to methylation reactions in heterogeneous media. After activation with 29% (w/w) NaOH solution, methylation reactions were carried out both with dimethyl sulfate (DMS) and methyl iodide (MI). The effects of the pressing ratio, reaction time and type of methylation agent were studied. The better yields were obtained with dimethylsulphate and the pressing ratio and reaction time were not signficant over the yield. Methylcellulose (MC) of...

  12. Engineering structural integrity issues in the pulp and paper industry

    International Nuclear Information System (INIS)

    Garner, A.; Singbeil, D.

    2002-01-01

    ESI issues for Pulp and Paper (P and P) plant are reviewed. Five typical processes are covered, namely: Chemical Pulping, Bleaching, Chemical Recovery, Mechanical Pulping and Papermaking. Equipment, chemical environments and failure modes are summarized with examples from each process. Pressure, temperature, corrosion and rotation are typical sources of risk, which is managed by appropriate inspection. The nature of the P and P Industry and its technology supply is summarized: current trends are consolidation and outsourcing. Three examples are presented to illustrate typical ESI issues: deaerator cracking where the P and P Industry alerted others to this serious cross-industry problem; pressure vessel safety factors and inconsistent international codes; and caustic cracking in continuous kraft digesters, which required rapid and concerted action to diagnose and control. In the future better predictability, data-bases, more formal risk based inspection and fitness-for-service assessments are envisaged. (author)

  13. VOC Control in Kraft Mills; FINAL

    International Nuclear Information System (INIS)

    Zhu, J.Y.; Chai, X.-S.; Edwards, L.L.; Gu, Y.; Teja, A.S.; Kirkman, A.G.; Pfromm, P.H.; Rezac, M.E.

    2001-01-01

    The formation of volatile organic compounds (VOCs), such as methanol, in kraft mills has been an environmental concern. Methanol is soluble in water and can increase the biochemical oxygen demand. Furthermore, it can also be released into atmosphere at the process temperatures of kraft mill-streams. The Cluster Rule of the EPA now requires the control of the release of methanol in pulp and paper mills. This research program was conducted to develop a computer simulation tool for mills to predict VOC air emissions. To achieve the objective of the research program, much effort was made in the development of analytical techniques for the analysis of VOC and determination of vapor liquid partitioning coefficient of VOCs in kraft mill-streams using headspace gas chromatography. With the developed analytical tool, methanol formation in alkaline pulping was studied in laboratory to provide benchmark data of the amount of methanol formation in pulping in kraft mills and for the validation of VOC formation and vapor-liquid equilibrium submodels. Several millwide air and liquid samplings were conducted using the analytical tools developed to validate the simulation tool. The VOC predictive simulation model was developed based on the basic chemical engineering concepts, i.e., reaction kinetics, vapor liquid equilibrium, combined with computerized mass and energy balances. Four kraft mill case studies (a continuous digester, two brownstock washing lines, and a pre-evaporator system) are presented and compared with mill measurements. These case studies provide valuable, technical information for issues related to MACT I and MACT II compliance, such as condensate collection and Clean-Condensate-Alternatives (CCA)

  14. Integration of a kraft pulping mill into a forest biorefinery: pre-extraction of hemicellulose by steam explosion versus steam treatment.

    Science.gov (United States)

    Martin-Sampedro, Raquel; Eugenio, Maria E; Moreno, Jassir A; Revilla, Esteban; Villar, Juan C

    2014-02-01

    Growing interest in alternative and renewable energy sources has brought increasing attention to the integration of a pulp mill into a forest biorefinery, where other products could be produced in addition to pulp. To achieve this goal, hemicelluloses were extracted, either by steam explosion or by steam treatment, from Eucalyptus globulus wood prior to pulping. The effects of both pre-treatments in the subsequent kraft pulping and paper strength were evaluated. Results showed a similar degree of hemicelluloses extraction with both options (32-67% of pentosans), which increased with the severity of the conditions applied. Although both pre-treatments increased delignification during pulping, steam explosion was significantly better: 12.9 kappa number vs 22.6 for similar steam unexploded pulps and 40.7 for control pulp. Finally, similar reductions in paper strength were found regardless of the type of treatment and conditions assayed, which is attributed to the increase of curled and kinked fibers. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Sisal organosolv pulp as reinforcement for cement based composites

    Directory of Open Access Journals (Sweden)

    Ana Paula Joaquim

    2009-09-01

    Full Text Available The present work describes non-conventional sisal (Agave sisalana chemical (organosolv pulp from residues of cordage as reinforcement to cement based materials. Sisal organosolv pulp was produced in a 1:1 ethanol/water mixture and post chemically and physically characterized in order to compare its properties with sisal kraft pulp. Cement based composites reinforced with organosolv or kraft pulps and combined with polypropylene (PP fibres were produced by the slurry de-watering and pressing method as a crude simulation of the Hatschek process. Composites were evaluated at 28 days of age, after exposition to accelerated carbonation and after 100 soak/dry cycles. Composites containing organosolv pulp presented lower mechanical strength, water absorption and apparent porosity than composites reinforced with kraft pulp. The best mechanical performance after ageing was also achieved by samples reinforced with kraft pulp. The addition of PP fibres favoured the maintenance of toughness after ageing. Accelerated carbonation promoted the densification of the composites reinforced with sisal organosolv + PP fibres.

  16. Penetration of 38% hydrogen peroxide into the pulp chamber in bovine and human teeth submitted to office bleach technique.

    Science.gov (United States)

    Camargo, Samira Esteves Afonso; Valera, Marcia Carneiro; Camargo, Carlos Henrique Ribeiro; Gasparoto Mancini, Maria Nadir; Menezes, Marcia Maciel

    2007-09-01

    This study evaluated the pulp chamber penetration of peroxide bleaching agent in human and bovine teeth after office bleach technique. All the teeth were sectioned 3 mm apical of the cement-enamel junction and were divided into 2 groups, A (70 third human molars) and B (70 bovine lateral incisors), that were subdivided into A1 and B1 restored by using composite resin, A2 and B2 by using glass ionomer cement, and A3 and B3 by using resin-modified glass ionomer cement; A4, A5, B4, and B5 were not restored. Acetate buffer was placed in the pulp chamber, and the bleaching agent was applied for 40 minutes as follows: A1-A4 and B1-B4, 38% hydrogen peroxide exposure and A5 and B5, immersion into distilled water. The buffer solution was transferred to a glass tube in which leuco crystal violet and horseradish peroxidase were added, producing a blue solution. The optical density of the blue solution was determined by spectrophotometer and converted into microgram equivalents of hydrogen peroxide. Data were submitted to analysis of variance and Dunnett, Kruskal-Wallis, and Tukey tests (5%). A higher level of hydrogen peroxide penetrated into the pulp chamber in resin-modified glass ionomer cements in bovine (0.79 +/- 0.61 microg) and human (2.27 +/- 0.41 microg) groups. The bleaching agent penetration into the pulp chamber was higher in human teeth for any experimental situation. The penetration of the hydrogen peroxide depends on restorative materials, and under the conditions of this study human teeth are more susceptible to penetration of bleaching agent into the pulp chamber than bovine teeth.

  17. Swelling and hydrolysis kinetics of Kraft pulp fibers in aqueous 1-butyl-3-methylimidazolium hydrogen sulfate solutions.

    Science.gov (United States)

    Mao, Jia; Abushammala, Hatem; Pereira, Laura Barcellos; Laborie, Marie-Pierre

    2016-11-20

    1Butyl-3-methylimidazolium hydrogen sulfate ([Bmim]HSO4) is efficient at extracting cellulose nanocrystals from pulp fibers. To shed some light on the respective contributions of swelling and hydrolysis of pulp fibers by [Bmim]HSO4, the physical, structural and morphological characteristics of hardwood Kraft pulp fibers were monitored under various conditions of temperature, water content and time. Swelling was largely compounded by hydrolysis at the highest temperatures (120°C) as evidenced by mass loss and reduced degree of polymerization (DPn) at this temperature. At 120°C only, water content appeared to play a significant role on the extent of hydrolysis. At this temperature, a heterogeneous kinetic model involving weak links and amorphous regions best described the experimental data. Hydrolysis rates were maximum at 25% water content in the aqueous ionic liquid. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. ISOLASI, SKRINING DAN IDENTIFIKASI JAMUR XILANOLITIK LOKAL YANG BERPOTENSI SEBAGAI AGENSIA PEMUTIH PULP YANG RAMAH LINGKUNGAN (Isolation, Screening and Identification Xylanolytic Local Fungi that Potentially as Pulp Bleaching Agents

    Directory of Open Access Journals (Sweden)

    Elisa Nurnawati

    2015-01-01

    Xylanase has great potential for industry application. Application of xylanase can be done in pretreatment of pulp bleaching in the pulp and paper industry. Enzyme application can reduce the use of chlorine compounds that are harmful to the environment. Therefore, xylanase that used in pulp bleaching should be free of cellulase activity. Fungi are one of the groups of microbes that are able to produce xylanase. The aims of this study was to obtain local xylanase-producing fungal isolates from soil that assumed contain of xylan. The source of fungal isolates were the soil around the pulp and paper industry; Acacia forests in the district Ogan Ilir and Muara Enim, South Sumatra; Wanagama, Yogyakarta; sawmills in Palembang and Yogyakarta; and Palembang landfill. Based on the initial screening in the agar basal medium, 111 fungal isolates were obtained. Most of them were the xylanase-producing fungi, but only 12 fungal isolates that have high xylanolytic capabilities. Further screening was performed on xylan liquid basal medium. The results showed that the fungus identified as Chaetomium globosum, Penicillium simplicissimum, Aspergillus tamarii and Monocillium have higher xylanase specific activity than the other isolates. They were also have lignolytic and cellulolytic activities. Therefore, fungal xylanase potentially developed as a pulp bleaching agent.

  19. Effects of the concentration and composition of in-office bleaching gels on hydrogen peroxide penetration into the pulp chamber.

    Science.gov (United States)

    Mena-Serrano, A P; Parreiras, S O; do Nascimento, E M S; Borges, C P F; Berger, S B; Loguercio, A D; Reis, A

    2015-01-01

    In tooth whitening, the hydrogen peroxide (HP) diffuses in the enamel and dentin, reaching the pulp. This in vitro study aimed to quantify the penetration of HP in the pulp chamber in teeth submitted to bleaching agents of different concentrations of HP without calcium (HP 20% [20CF], HP 35% [35CF]) and with calcium (HP 20% [20CC], HP 35% [35CC]). Fifty human premolars were sectioned 3 mm from the cemento-enamel junction and the pulp tissue was removed. The teeth were divided into five groups according to treatment and with a control group (n=10). An acetate buffer solution was placed in the pulp chamber of all teeth. The control group was exposed only to distilled water, while the other groups were treated with a bleaching procedure, according to the manufacturer's recommendations. After treatment, the acetate buffer solution was transferred to a glass tube in which leuco-crystal violet and peroxidase solutions were added, resulting in a blue solution. The optical density of this blue solution was determined spectrophotometrically and converted into micrograms equivalent to the HP. Data were analyzed using analysis of variance and Tukey tests (α=0.05). The HP concentration did not affect the HP inside the pulp chamber, but the presence of calcium significantly reduced it (p<0.0001). The amount of HP that reaches the pulp chamber depends on the bleaching protocol and the product employed, and it seems to be less affected by HP concentration.

  20. Characterization of solid wastes from kraft pulp industry for ceramic materials development purposes; Caracterizacao de residuos solidos da industria de celulose tipo kraft visando sua aplicacao no desenvolvimento de materiais ceramicos

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, L.R.; Francisco, M.A.C.O.; Sagrillo, V.P.D.; Louzada, D.M.; Entringer, J.M.S. [Instituto Federal do Espirito Santo (IFES), Vitoria, ES (Brazil)

    2016-07-01

    The Kraft pulp industry generates a large amount of solid wastes. Due this large quantity, the target of this study is characterize inorganic solid wastes, dregs, grits and lime mud, from the step of reagents recovery of Kraft process, aiming evaluate the potentiality of their use as alternative raw material on development of ceramic materials. Initially, the wastes were dried and ground, then they were subjected to the following characterization techniques: pH analysis, particle size analysis, X ray fluorescence, X ray diffraction, differential thermal analysis and thermogravimetric analysis and scanning electron microscopy. According to the results, it may be concluded that these wastes could be used as raw material in production of red ceramic and luting materials. (author)

  1. Pulp quality from small-diameter trees.

    Science.gov (United States)

    G.C. Myers; S. Kumar; R.R. Gustafson; R.J. Barbour; S.M. Abubakr

    1997-01-01

    Kraft and thermomechanical (TMP) pulps were prepared and evaluated from lodgepole pine and mixed Douglas-fir/western larch sawmill residue chips; lodgepole pine, Douglas-fir, and western larch submerchantable logs; and lodgepole pine, Douglas-fir, and western larch small trees and tops. Kraft pulp from small trees and tops was identical to that from submerchantable...

  2. Morphological development of cellulose fibrils of a bleached eucalyptus pulp by mechanical fibrillation

    Science.gov (United States)

    Q.Q. Wang; J.Y. Zhu; R. Gleisner; T.A. Kuster; U. Baxa; S.E. McNeil

    2012-01-01

    This study reports the production of cellulose nanofibrils (CNF) from a bleached eucalyptus pulp using a commercial stone grinder. Scanning electronic microscopy and transmission electronic microscopy imaging were used to reveal morphological development of CNF at micro and nano scales, respectively. Two major structures were identified (1) highly kinked, naturally...

  3. A survey of present levels of radiocesium in Swedish pulp mill liquors and the implications for wood radiocesium transfer factors. Using Kraft mill liquors as an indicator of wood radiocesium contamination

    International Nuclear Information System (INIS)

    Ravila, A.; Holm, E.

    2000-01-01

    A survey was initiated to depict and compare the present activity levels in pulp mill liquors from various mill locations. The 137 Cs levels in pulp mill liquors were compared with the mill location and the deposition pattern of the Chernobyl fallout and nuclear weapons fallout. The large input of wood (about 2500 m 3 per day) to an average Nordic Kraft mill and the relatively long-term retention time for radiocesium in the Kraft mill recovery cycle enables representative sampling of substances directly related to the activity concentration in wood. (author)

  4. Excess heat from kraft pulp mills: Trade-offs between internal and external use in the case of Sweden-Part 1: Methodology

    International Nuclear Information System (INIS)

    Svensson, Inger-Lise; Joensson, Johanna; Berntsson, Thore; Moshfegh, Bahram

    2008-01-01

    Excess heat from a kraft pulp mill can be used either internally to increase the level of efficiency in the mill, or externally for example as district heating. This paper presents an approach to investigate the competition between external and internal use through modelling the pulp mill and an energy company (ECO) within the same system boundary. Three different sizes of ECOs with different district heating demands are studied. To investigate the competitiveness of using industrial excess heat as district heating compared with other heat production techniques, the option of investing in excess heat use is introduced, along with the possibility for the ECO to invest in biomass combined heat and power (CHP), waste CHP and natural gas combined cycle (NGCC). To evaluate the robustness of the model, alternative solutions are identified and will be used as a comparison to the optimal solutions. The model has been verified by comparing the results with previous studies concerning kraft pulp mills and with related studies regarding district heating and real ECOs. Finally, the approach presented in this part of the study will be used in the second part in order to investigate the trade-off between internal and external use of excess heat under different future energy market scenarios

  5. RE-UTILIZATION OF INORGANIC SOLID WASTE (LIME MUD AS FOREST ROAD STABILIZER FROM THE CHEMICAL RECOVERY PROCESS IN KRAFT PULP MILL

    Directory of Open Access Journals (Sweden)

    Habip Eroğlu

    2005-04-01

    Full Text Available Waste handling is a concern in all pulp and paper mills. Best available techniques for reducing waste is to minimize the generation of solid waste and/or reuse these materials, wherever practicable. One of the most important solid wastes is lime mud which is generated from the kraft pulping in its chemical recovery process. This paper explores the composition of lime mud resulting from the chemical recovery unite of kraft pulp mill and investigation of this waste for re-using beneficially on sub grade and pavement of forest road as a alternative disposal method. Lime mud obtained from the re-causticising process in SEKA pulp mill that utilizes wheat straw and reed as the principal raw material was supplied with % 47 water content and its chemical and physical characterisations was performed according to standard methods. Dried waste to environmental condition was mixed with certain amount to composite cement for using on pavement and sandy clay, loamy clay and clay soils for enriching forest road sub grade properties. In order to investigate the lime mud addition on pavement and sub grade properties necessary physical tests were performed. As a consequence this study reveals that while waste of lime mud causes environmental and economical problem with conventional disposal techniques and/or abandoning to environment, this waste can be used as good stabilisation materials on forest road sub-grade and pavement without any environmental problem.

  6. Avaliação da madeira e da polpação kraft em clones de eucaliptos Wood evaluation and Kraft pulping in eucalypts clones

    Directory of Open Access Journals (Sweden)

    Adriana de Fátima Gomes Gouvêa

    2009-12-01

    Full Text Available A produção de celulose de baixo custo e alta qualidade requer madeira adequada e bem selecionada. A seleção de clones superiores tem sido realizada com base em critérios como densidade básica, rendimento gravimétrico da polpação e composição química da madeira, especialmente de celulose, hemiceluloses, extrativos e ligninas. O objetivo deste trabalho foi avaliar as características da madeira de Eucalyptus, por método destrutivo, e a produção de polpa celulósica kraft em seis clones. Utilizaram-se cinco árvores de cada clone, aos 3 anos de idade, plantadas em espaçamento 3,0 m x 3,3 m, nas regiões de Cocais, Guanhães, Rio Doce e Santa Bárbara, Estado de Minas Gerais. A densidade básica foi medida em discos extraídos a 1,3 m de altura do solo (DAP e em cavacos da árvore inteira (amostra composta. A composição química foi medida em amostras de serragem, retiradas no DAP. Os cozimentos foram efetuados a partir de cavacos da árvore inteira. Verificou-se que a densidade medida no DAP foi ligeiramente superior à medida nos cavacos da árvore toda. A composição química geral da madeira foi muito influenciada pelo tipo de clone, local de plantio e interação. Locais mais montanhosos produziram madeira com maior teor de celulose e menor de hemicelulose. A madeira do clone F da região de Santa Bárbara e Cocais apresentaram madeiras de qualidade inferior para produção de polpa celulósica. Os melhores rendimentos de polpação kraft foram alcançados com o clone B nas regiões de Guanhães e Santa Bárbara.Low cost and high quality cellulose production demands appropriate wood. The selection of superior clones has been done based on some criteria as basic density, gravimetric yield of pulping and wood chemical composition, especially of cellulose, hemicelluloses, extractive and lignin contents. This study aimed at evaluating the characteristics of the Eucalyptus wood, by destructive methods, and the Kraft pulping

  7. Cynara cardunculus L. alkaline pulps: alternatives fibres for paper and paperboard production.

    Science.gov (United States)

    Abrantes, S; Amaral, M E; Costa, A P; Duarte, A P

    2007-11-01

    The pulping of Cynara cardunculus L. (cardoon) was performed under conditions for kraft, kraft-AQ and soda-AQ processes. The best results in terms of delignification degree, expressed as kappa number, pulp viscosity and screened yield, were obtained for the kraft-AQ process with 0.20% of anthraquinone (AQ). The papermaking potential of the selected pulp was studied attending to biometric fibre characterisation, refining aptitude, optical and strength properties. All properties were compared against a Eucalyptus globulus pulp at different refining degrees. The cardoon pulp was also evaluated concerning its potential to board manufacture, alone and in mixtures with pine pulp, giving rise to promising results for liner manufacture.

  8. Final chlorine dioxide stage at near-neutral pH for bleaching eucalypt pulp

    Directory of Open Access Journals (Sweden)

    Robisnéa A. Ribeiro

    2014-01-01

    Full Text Available It is well known that pH is an important parameter for controlling the eucalyptus pulp bleaching when using the final chlorine dioxide stage, since it affects the effectiveness of the process. Recommendations found in the literature for operating are in the 3.5 to 4.0 range. However, in this paper it was shown that final chlorine dioxide has better performance, with significant brightness gain while also preserving pulp quality, when it is operated at near neutral pH. This result can be explained by the generation of sodium bicarbonate in situ upon adding carbon dioxide at this stage.

  9. Sisal organosolv pulp as reinforcement for cement based composites

    OpenAIRE

    Joaquim, Ana Paula; Tonoli, Gustavo Henrique Denzin; Santos, Sérgio Francisco Dos; Savastano Junior, Holmer

    2009-01-01

    The present work describes non-conventional sisal (Agave sisalana) chemical (organosolv) pulp from residues of cordage as reinforcement to cement based materials. Sisal organosolv pulp was produced in a 1:1 ethanol/water mixture and post chemically and physically characterized in order to compare its properties with sisal kraft pulp. Cement based composites reinforced with organosolv or kraft pulps and combined with polypropylene (PP) fibres were produced by the slurry de-watering and pressin...

  10. Treatment of the Bleaching Effluent from Sulfite Pulp Production by Ceramic Membrane Filtration

    Directory of Open Access Journals (Sweden)

    Mehrdad Ebrahimi

    2015-12-01

    Full Text Available Pulp and paper waste water is one of the major sources of industrial water pollution. This study tested the suitability of ceramic tubular membrane technology as an alternative to conventional waste water treatment in the pulp and paper industry. In this context, in series batch and semi-batch membrane processes comprising microfiltration, ultrafiltration and nanofiltration, ceramic membranes were developed to reduce the chemical oxygen demand (COD and remove residual lignin from the effluent flow during sulfite pulp production. A comparison of the ceramic membranes in terms of separation efficiency and performance revealed that the two-stage process configuration with microfiltration followed by ultrafiltration was most suitable for the efficient treatment of the alkaline bleaching effluent tested herein, reducing the COD concentration and residual lignin levels by more than 35% and 70%, respectively.

  11. Treatment of the Bleaching Effluent from Sulfite Pulp Production by Ceramic Membrane Filtration.

    Science.gov (United States)

    Ebrahimi, Mehrdad; Busse, Nadine; Kerker, Steffen; Schmitz, Oliver; Hilpert, Markus; Czermak, Peter

    2015-12-31

    Pulp and paper waste water is one of the major sources of industrial water pollution. This study tested the suitability of ceramic tubular membrane technology as an alternative to conventional waste water treatment in the pulp and paper industry. In this context, in series batch and semi-batch membrane processes comprising microfiltration, ultrafiltration and nanofiltration, ceramic membranes were developed to reduce the chemical oxygen demand (COD) and remove residual lignin from the effluent flow during sulfite pulp production. A comparison of the ceramic membranes in terms of separation efficiency and performance revealed that the two-stage process configuration with microfiltration followed by ultrafiltration was most suitable for the efficient treatment of the alkaline bleaching effluent tested herein, reducing the COD concentration and residual lignin levels by more than 35% and 70%, respectively.

  12. Effect of ultrasonic pre-treatment of thermomechanical pulp on hydrogen peroxide bleaching

    Science.gov (United States)

    Loranger, E.; Charles, A.; Daneault, C.

    2012-12-01

    Ultrasound pre-treatments of softwood TMP had been carried to evaluate its impact on the efficiency of hydrogen peroxide bleaching. The trials were performed after a factorial design of experiment using frequency, power and time as variables. The experiments were conducted in an ultrasonic bath and then bleached with hydrogen peroxide. Measurements such as brightness, L*A*B* color system coordinate, residual hydrogen peroxide and metal content were evaluated on bleached pulp. The results indicate that the effect of ultrasonic treatment on brightness was dependent on the ultrasound frequency used; the brightness increased slightly at 68 kHz and decreased at 40 and 170 kHz. These results were correlated to the ultrasound effect on the generation of transition metals (copper, iron and manganese) which are responsible for catalytic decomposition of hydrogen peroxide. The influence of metal interference was minimized by using a chelating agent such as diethylene triamine pentaacetic acid (DTPA). With the results obtained in this study we have identified a set of option conditions, e.g. 1000 W, 40 kHz, 1.5 % consistency and 0.2% addition of DTPA prior to the bleaching stage (after ultrasonic pre-treatment) who improve brightness by 2.5 %ISO.

  13. A combined acidification/PEO flocculation process to improve the lignin removal from the pre-hydrolysis liquor of kraft-based dissolving pulp production process.

    Science.gov (United States)

    Shi, Haiqiang; Fatehi, Pedram; Xiao, Huining; Ni, Yonghao

    2011-04-01

    The presence of lignin impairs the utilization of the hemicelluloses dissolved in the pre-hydrolysis liquor (PHL) of the kraft-based dissolving pulp production process. In this paper, a novel process was developed by combining the acidification and poly ethylene oxide (PEO) flocculation concepts to improve the lignin removal. The results showed that the lignin removal was improved by the addition of PEO to the acidified PHL, particularly at a low pH of 1.5. The main mechanisms involved are the lignin/PEO complex formation and the bridging of the formed complexes. This hypothesis was supported by the turbidity, FTIR and particle size measurements. Interestingly, the hemicelluloses removal from the acidification/PEO flocculation was marginal, which would be beneficial for the down-stream ethanol production from the PHL. Additionally, a process flow diagram was proposed that incorporates this new concept into the existing configuration of kraft-based dissolving pulp production process. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. Caffeic acid production by simultaneous saccharification and fermentation of kraft pulp using recombinant Escherichia coli.

    Science.gov (United States)

    Kawaguchi, Hideo; Katsuyama, Yohei; Danyao, Du; Kahar, Prihardi; Nakamura-Tsuruta, Sachiko; Teramura, Hiroshi; Wakai, Keiko; Yoshihara, Kumiko; Minami, Hiromichi; Ogino, Chiaki; Ohnishi, Yasuo; Kondo, Ahikiko

    2017-07-01

    Caffeic acid (3,4-dihydroxycinnamic acid) serves as a building block for thermoplastics and a precursor for biologically active compounds and was recently produced from glucose by microbial fermentation. To produce caffeic acid from inedible cellulose, separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) reactions were compared using kraft pulp as lignocellulosic feedstock. Here, a tyrosine-overproducing Escherichia coli strain was metabolically engineered to produce caffeic acid from glucose by introducing the genes encoding a 4-hydroxyphenyllactate 3-hydroxylase (hpaBC) from Pseudomonas aeruginosa and tyrosine ammonia lyase (fevV) from Streptomyces sp. WK-5344. Using the resulting recombinant strain, the maximum yield of caffeic acid in SSF (233 mg/L) far exceeded that by SHF (37.9 mg/L). In the SSF with low cellulase loads (≤2.5 filter paper unit/g glucan), caffeic acid production was markedly increased, while almost no glucose accumulation was detected, indicating that the E. coli cells experienced glucose limitation in this culture condition. Caffeic acid yield was also negatively correlated with the glucose concentration in the fermentation medium. In SHF, the formation of by-product acetate and the accumulation of potential fermentation inhibitors increased significantly with kraft pulp hydrolysate than filter paper hydrolysate. The combination of these inhibitors had synergistic effects on caffeic acid fermentation at low concentrations. With lower loads of cellulase in SSF, less potential fermentation inhibitors (furfural, 5-hydroxymethyfurfural, and 4-hydroxylbenzoic acid) accumulated in the medium. These observations suggest that glucose limitation in SSF is crucial for improving caffeic acid yield, owing to reduced by-product formation and fermentation inhibitor accumulation.

  15. Biobleaching chemistry of laccase-mediator systems on high-lignin-content kraft pulps

    International Nuclear Information System (INIS)

    Chakar, F.S.; Ragauskas, A.J.

    2004-01-01

    A high-lignin-content softwood kraft pulp was reacted with laccase in the presence of 1-hydroxybenzotriazole (HBT), N-acetyl-N-phenylhydroxylamine (NHA), and violuric acid (VA). The biodelignification response with violuric acid was superior to both 1-hydroxybenzotriazole and N-acetyl-N-phenylhydroxylamine. NMR analysis of residual lignins isolated before and after the biobleaching treatments revealed that the latter material was highly oxidized and that the magnitude of structural changes was most pronounced with the laccase - violuric acid biobleaching system. An increase in the content of carboxylic acid groups and a decrease in methoxyl groups were noted with all three laccase-mediator systems. The oxidation biobleaching pathway is directed primarily towards noncondensed C5 phenolic lignin functional structures for all three laccase-mediated systems. The laccase - violuric acid system was also reactive towards C5-condensed phenolic lignin structures. (author)

  16. Caracterização tecnológica, para produção de celulose, da nova geração de clones de Eucalyptus do Brasil Technological characterization of the new generation of Eucalyptus clones in Brazil for kraft pulp production

    Directory of Open Access Journals (Sweden)

    José Lívio Gomide

    2005-02-01

    Full Text Available Foram analisados clones de Eucalyptus de última geração, pertencentes às principais empresas brasileiras de celulose. Os estudos consistiram numa caracterização tecnológica detalhada da qualidade das madeiras utilizadas no processamento fabril das empresas. Foram realizadas análise químicas detalhadas das madeiras e cozimentos kraft, simulando-se uma das modernas técnica de digestor contínuo. Os resultados indicaram a alta qualidade dos clones de Eucalyptus atualmente plantados no Brasil para produção de celulose.Last generation of Eucalyptus clones pulped by the main Brazilian kraft pulp mills were used for this study. Detailed chemical analysis of the woods were carried out to establish the wood quality. Laboratory simulation of a modern continuous digester technique was used for pulp production. Results demonstrated the high quality of Eucalyptus clones wood that are being planted in Brazil for kraft pulp production.

  17. Techno-Economic Analysis of the Optimum Softwood Lignin Content for the Production of Bioethanol in a Repurposed Kraft Mill

    Directory of Open Access Journals (Sweden)

    Shufang Wu

    2014-09-01

    Full Text Available Kraft pulping is one possible pretreatment for softwood to economically produce bioethanol. This work evaluates the techno-economic potential of using the kraft process for producing bioethanol from softwoods in a repurposed or co-located kraft mill. Pretreated loblolly pine was enzymatically hydrolyzed at low enzyme dosages of 5 and 10 FPU/g of substrate. Pretreated residue with 13% lignin content had the highest sugar recovery, 32.7% and 47.7% at 5 and 10 FPU/g, respectively. The pretreated residues were oxygen delignified and refined. In all cases, oxygen delignification improved sugar recovery, while refining was mostly effective for pulps with high lignin content. At 5 FPU/g, the sugar recovery for all kraft pulps was 51 to 53% with oxygen delignification and refining. Increasing the enzyme dosage to 10 FPU/g increased the sugar recovery for these pulps to greater than 60%. Economic analysis for the pulps with different initial lignin content showed that kraft pulps with an initial lignin content of 6.7% with oxygen delignification had an ethanol yield of 285 L/ODt wood and the lowest total production cost of $0.55/L. Pulps with initial lignin content of 18.6% had a total production cost of $0.64/L with an ethanol yield of 264 L/ODt wood.

  18. Development of hemicelluloses biorefineries for integration into kraft pulp mills

    Science.gov (United States)

    Ajao, Olumoye Abiodun

    The development and wide spread acceptance of production facilities for biofuels, biochemicals and biomaterials is an important condition for reducing reliance on limited fossil resources and transitioning towards a global biobased economy. Pulp and paper mills in North America are confronted with high energy prices, high production costs and intense competition from emerging economies and low demand for traditional products. Integrated forest biorefineries (IFBR) have been proposed as a mean to diversify their product streams, increase their revenue and become more sustainable. This is feasible because they have access to forest biomass, an established feedstock supply chain and wood processing experience. In addition, the integration of a biorefinery process that can share existing infrastructure and utilities on the site of pulp mill would significantly lower investment cost and associated risks. Kraft pulping mills are promising receptor processes for a biorefinery because they either possess a prehydrolysis step for extracting hemicelluloses sugars prior to wood pulping or it can be added by retrofit. The extracted hemicelluloses could be subsequently transformed into a wide range of value added products for the receptor mill. To successfully implement hemicelluloses biorefinery, novel processes that are technically and economically feasible are required. It is necessary to identify products that would be profitable, develop processes that are energy efficient and the receptor mill should be able to supply the energy, chemicals and material demands of the biorefinery unit. The objective of this thesis is to develop energy efficient and economically viable hemicelluloses biorefineries for integration into a Kraft pulping process. A dissolving pulp mill was the reference case study. The transformation of hemicellulosic sugars via a chemical and biochemical conversion pathway, with furfural and ethanol as representative products for each pathway was studied. In

  19. Utilização de surfactantes, na polpação kraft de madeira de eucalipto, como auxiliar na remoção de extrativos lipofílicos Surfactant utilization in kraft pulping of eucalyptus wood to improve lipophilic extractives removal

    Directory of Open Access Journals (Sweden)

    Deusanilde de Jesus Silva

    2004-12-01

    Full Text Available Problemas de deposição de "pitch" em fábricas de celulose e de papel são atribuídos aos extrativos lipofílicos existentes na madeira. Uma das maneiras mais eficientes de controlar essa deposição é através da remoção de seus precursores do sistema, logo que possível, nas etapas de cozimento, lavagem da polpa marrom e pré-deslignificação com oxigênio. O uso de surfactantes como aditivos da polpação tem sido investigado, mas há grande deficiência de informações técnicas, e a aplicação industrial é, ainda, incipiente. A proposta deste trabalho foi analisar a viabilidade de minimizar a deposição de "pitch", intensificando a remoção de suas substâncias precursoras na etapa de polpação pelo uso de tensoativos sintéticos com propriedades umectantes e solubilizantes. Foram testados 20 princípios ativos de surfactantes em cozimento kraft convencional de madeira de eucalipto. Os resultados, alguns estatisticamente significativos, apontaram redução do teor de substâncias lipofílicas na polpa marrom. Foi observado que a remoção dos extrativos lipofílicos da madeira é afetada, inversamente, pelo teor de óxido de eteno na molécula do surfactante. Outros parâmetros de cozimento, como deslignificação, rendimento, teor de rejeitos e viscosidade da polpa, foram também avaliados.Extractives are pitch precursors and may decrease pulping efficiency and affect pulp quality. Probably, the most efficient way to minimize pitch problems is to remove their precursors from the system during cooking, pulp washing and oxygen delignification. Use of surfactants as pulping additives has been investigated but technical information is deficient and industrial application is very incipient. The objective of this study was to analyze the performance of different surfactants as additives for kraft pulping of Eucalyptus wood. Twenty surfactants with different basic chemical structures were used. The results demonstrated that

  20. Effect of fluoride-treated enamel on indirect cytotoxicity of a 16% carbamide peroxide bleaching gel to pulp cells.

    Science.gov (United States)

    Soares, Diana Gabriela; Ribeiro, Ana Paula Dias; Lima, Adriano Fonseca; Sacono, Nancy Tomoko; Hebling, Josimeri; de Souza Costa, Carlos Alberto

    2013-01-01

    The aim of this study was to evaluate the possibility of fluoride solutions applied to enamel to protect pulp cells against the trans-enamel and transdentinal cytotoxicity of a 16% carbamide peroxide (CP) bleaching gel. The CP gel was applied to enamel/dentin discs adapted to aicial pulp chambers (8 h/day) during 1, 7 or 14 days, followed by fluoride (0.05% or 0.2%) application for 1 min. The extracts (culture medium in contact with dentin) were applied to MDPC-23 cells for 1 h, and cell metabolism (MTT assay), alkaline phosphatase (ALP) activity and cell membrane damage (flow cytometry) were analyzed. Knoop microhardness of enamel was also evaluated. Data were analyzed statistically by ANOVA and Kruskal-Wallis tests (α=0.05). For the MTT assay and ALP activity, significant reductions between the control and the bleached groups were observed (p0.05), regardless of fluoride application or treatment days. Flow cytometry analysis demonstrated 30% of cell membrane damage in all bleached groups. After 14 days of treatment, the fluoride-treated enamel presented significantly higher microhardness values than the bleached-only group (pfluoride solutions, the treated enamel surface did not prevent the toxic effects caused by the 16% CP gel to odontoblast-like cells.

  1. The effects of high energy radiation on the pulping properties of Pinus radiation and Eucalyptus regnans

    International Nuclear Information System (INIS)

    McLaren, K.G.; Garland, C.P.; Higgins, H.G.

    1976-01-01

    Studies have been made of the effects of high energy radiation on the pulping behaviour of Eucalyptus regnans and Pinus radiata. Pre-irradiation of wood chips with small doses of 60 Co gamma radiation (up to about 0.2 Mrad) caused little degradation of the cellulose, and had only minor effects on the kraft pulping properties of both wood species. Pulp yield, Kappa number and strength properties of the pulps showed little change. There was also little effect on the bisulphite cooking of Pinus radiata. As the dose was increased to 1 Mrad, degradation of cellulose (as indicated by degree of polymerisation measurements) became significant, and Kraft pulp yields from both woods showed small reductions. The Kappa number and physical properties of these pulps were little affected at this dose level. A gamma radiation dose of 10 Mrad produced marked depolymerisation of the cellulose, and big reductions in kraft and neutral sulphite semi-chemical pulp yields. The kraft pulps showed a much higher lignin content. Some low dose (0.15 Mrad) irradiations on thin chips were carried out with a 1 MeV electron accelerator. In contrast to comparable gamma irradiations, this treatment produced discernible changes in kraft pulping behaviour. The pulp yield, under the same cooking conditions, appears to be slightly higher, but the Lignin content of the pulp was increased. (Author)

  2. EVALUATION OF LINERBOARD PROPERTIES FROM MALAYSIAN CULTIVATED KENAF SODA-ANTHRAQUINONE PULPS VERSUS COMMERCIAL PULPS

    Directory of Open Access Journals (Sweden)

    Ahmad Azizi Mossello

    2010-06-01

    Full Text Available Malaysian cultivated kenaf has been identified as a suitable raw material for linerboard production. This study examines the soda-antraquinone (soda-AQ pulp of kenaf fibers versus old corrugated container (OCC and unbleached softwood kraft pulps as the main sources for linerboard production. The results showed significant differences among the pulp properties. The unbleached kraft pulp with very high freeness required high beating to reach an optimized freeness and produced paper with the highest strength properties, except for tear resistance. The OCC gave paper with the lowest strength properties. In the case of kenaf fractions, bast pulp with high freeness needed less beating than softwood and produced paper with high tear resistance. Core fiber, which had the lowest freeness and highest drainage time, led to paper with high strength but very low tear resistance. Kenaf whole stem pulp showed intermediate properties between core and bast and close to those of unbleached softwood pulp, but with very lower beating requirement. Finally, kenaf whole stem, due to its strength properties, moderate separation cost, and simple pulping process, was judged to be more suitable for commercialization for linerboard production in Malaysia.

  3. Process for purification of waste water produced by a Kraft process pulp and paper mill

    Science.gov (United States)

    Humphrey, M. F. (Inventor)

    1979-01-01

    The water from paper and pulp wastes obtained from a mill using the Kraft process is purified by precipitating lignins and lignin derivatives from the waste stream with quaternary ammonium compounds, removing other impurities by activated carbon produced from the cellulosic components of the water, and then separating the water from the precipitate and solids. The activated carbon also acts as an aid to the separation of the water and solids. If recovery of lignins is also desired, then the precipitate containing the lignins and quaternary ammonium compounds is dissolved in methanol. Upon acidification, the lignin is precipitated from the solution. The methanol and quaternary ammonium compound are recovered for reuse from the remainder.

  4. Kinetics of AOX Formation in Chlorine Dioxide Bleaching of Bagasse Pulp

    Directory of Open Access Journals (Sweden)

    Shuangxi Nie

    2014-07-01

    Full Text Available In this paper, a kinetic model of the first chlorine dioxide bleaching stage (D0 in an elemental chlorine-free (ECF bleaching sequence is presented for bagasse pulps. The model is based on the rate of adsorbable organic halogen (AOX formation. The effects of the chlorine dioxide dosage, the sulfuric acid dosage, and the reaction temperature on the AOX content of wastewater are examined. The reaction of AOX formation could be divided into two periods. A large amount of AOX was formed rapidly within the first 10 min. Ten minutes later, the AOX formation rate significantly decreased. The kinetics could be expressed as: dW⁄dt=660.8•e^(-997.98/T 〖•[ClO〗_2 ]^0.877•[H2SO4 ]^0.355•W^(-1.065, where W is the AOX content, t is the bleaching time (min, T is the temperature (K, [ClO2] is the dosage of chlorine dioxide (kg/odt, and [H2SO4] is the dosage of sulfuric acid (kg/odt. The fit of the experiment results obtained for different temperatures, initial chlorine dioxide dosages, initial sulfuric acid dosages, and AOX content were very good, revealing the ability of the model to predict typical mill operating conditions.

  5. Investigation of pulping and paper making potential of weeds

    Directory of Open Access Journals (Sweden)

    omid Ghaffarzadeh Mollabashi

    2017-08-01

    Full Text Available Increasing use of wood products accompanying with resource constraint has revealed the importance of nonwood based material. In this study, pulping and papermaking potential of three varieties of weeds including Xanthium spinosum, Carthamus tinctorius and Cyperus papyrus have been considered. At first, chemical components of the samples i.e. cellulose, lignin and extractives have been measured following TAPPI standard test methods. Afterwards, pulping process based as soda and Kraft has been carried out and the pulp properties i.e. screen yield and reject, kappa number, caliper, bust index, tear index, brightness have been considered. According to the results, the amount cellulose, lignin and extractives have been measured for the Xanthium spinosum %38.15, %13.5 and 4.72, respectively. Theses parameters have been estimated about %38.25, %10.3 and % 2.95 for Carthamus tinctorius and %38.8, %19.2 and 4.4 in case of papyrus. The yield of soda and Kraft pulp of the papyrus was more than Xanthium spinosum and Carthamus tinctorius. Among all treatments, the highest screen yield related to soda pulping of Cyperus papyrus by %39.8 which has been obtained by 175 centigrade as a maximum temperature, L/W: 6/1, active alkaline: %30 and 90 minutes as the time at temperature. The lowest and highest amounts of the tear index were related to soda pulp sample of the Carthamus tinctorius and Kraft pulp sample of Xanthium spinosum by 2.49 and 8.1, respectively. In addition, the lowest and highest amounts of the bursting index were related to soda pulp sample of the Cyperus papyrus and Kraft pulp sample of Xanthium spinosum by 0.61and 2.48, respectively. Meanwhile, soda pulp sample of the Cyperus papyrus showed the highest amount of brightness with %45 ISO.

  6. Fibre Morphological Characteristics of Kraft Pulps of Acacia melanoxylon Estimated by NIR-PLS-R Models

    Directory of Open Access Journals (Sweden)

    Helena Pereira

    2015-12-01

    Full Text Available In this paper, the morphological properties of fiber length (weighted in length and of fiber width of unbleached Kraft pulp of Acacia melanoxylon were determined using TECHPAP Morfi® equipment (Techpap SAS, Grenoble, France, and were used in the calibration development of Near Infrared (NIR partial least squares regression (PLS-R models based on the spectral data obtained for the wood. It is the first time that fiber length and width of pulp were predicted with NIR spectral data of the initial woodmeal, with high accuracy and precision, and with ratios of performance to deviation (RPD fulfilling the requirements for screening in breeding programs. The selected models for fiber length and fiber width used the second derivative and first derivative + multiplicative scatter correction (2ndDer and 1stDer + MSC pre-processed spectra, respectively, in the wavenumber ranges from 7506 to 5440 cm−1. The statistical parameters of cross-validation (RMSECV (root mean square error of cross-validation of 0.009 mm and 0.39 μm and validation (RMSEP (root mean square error of prediction of 0.007 mm and 0.36 μm with RPDTS (ratios of performance to deviation of test set values of 3.9 and 3.3, respectively, confirmed that the models are robust and well qualified for prediction. This modeling approach shows a high potential to be used for tree breeding and improvement programs, providing a rapid screening for desired fiber morphological properties of pulp prediction.

  7. Simultaneous and rapid determination of multiple component concentrations in a Kraft liquor process stream

    Science.gov (United States)

    Li, Jian [Marietta, GA; Chai, Xin Sheng [Atlanta, GA; Zhu, Junyoung [Marietta, GA

    2008-06-24

    The present invention is a rapid method of determining the concentration of the major components in a chemical stream. The present invention is also a simple, low cost, device of determining the in-situ concentration of the major components in a chemical stream. In particular, the present invention provides a useful method for simultaneously determining the concentrations of sodium hydroxide, sodium sulfide and sodium carbonate in aqueous kraft pulping liquors through use of an attenuated total reflectance (ATR) tunnel flow cell or optical probe capable of producing a ultraviolet absorbency spectrum over a wavelength of 190 to 300 nm. In addition, the present invention eliminates the need for manual sampling and dilution previously required to generate analyzable samples. The inventive method can be used in Kraft pulping operations to control white liquor causticizing efficiency, sulfate reduction efficiency in green liquor, oxidation efficiency for oxidized white liquor and the active and effective alkali charge to kraft pulping operations.

  8. The Fractionation of Loblolly Pine Woodchips Into Pulp For Making Paper Products

    Energy Technology Data Exchange (ETDEWEB)

    Kiran Kadam, PhD

    2006-11-30

    The overall goal of the project was to test the PureVision biomass fractionation technology for making pulp from loblolly pine. A specific goal was to produce a pulp product that is comparable to pulp produced from the kraft process, while reducing the environmental effects of the kraft process, known to be a highly pollutant process. The overall goal of the project was met by using the biomass fractionation concept for making pulp product. This proof-of-concept study, done with Southern pine pinchips as feedstock, evaluated NaOH concentration and residence time as variables in single-stage cocurrent pulping process. It can be concluded that 1% NaOH is adequate for effective delignification using the PureVision process; this is about 1/3 of that used in the kraft process. Also, the PureVision process does not use sulfur-based chemicals such as N2S and hence, is environmentally more benign.

  9. Chapter 6: Prehydrolysis Pulping with Fermentation Coproducts

    Science.gov (United States)

    T.H. Wegner; C.J. Houtman; A.W. Rudie; B.L. Illman; P.J. Ince; E.M. Bilek; T.W. Jeffries

    2013-01-01

    Although the term “integrateed biorefinery” is new, the concept has long been familiar to the pulp and paper industry, where processes include biomass boilers providing combined heat and power, and byproducts of pulping include turpentine, fatty acids and resin acids. In the dominant kraft (or sulfate) pulping process, dissolved lignin and chemicals from the pulp...

  10. Concentrations of and application protocols for hydrogen peroxide bleaching gels: effects on pulp cell viability and whitening efficacy.

    Science.gov (United States)

    Soares, Diana Gabriela; Basso, Fernanda Gonçalves; Hebling, Josimeri; de Souza Costa, Carlos Alberto

    2014-02-01

    To assess the whitening effectiveness and the trans-enamel/trans-dentinal toxicity of experimental tooth-bleaching protocols on pulp cells. Enamel/dentine discs individually adapted to trans-well devices were placed on cultured odontoblast-like cells (MDPC-23) or human dental pulp cells (HDPCs). The following groups were formed: G1 - no treatment (control); G2 to G4 - 35% H2O2, 3 × 15, 1 × 15, and 1 × 5 min, respectively; and G5 to G7 - 17.5% H2O2, 3 × 15, 1 × 15, and 1 × 5 min, respectively. Cell viability and morphology were evaluated immediately after bleaching (T1) and 72 h thereafter (T2). Oxidative stress and cell membrane damage were also assessed (T1). The amount of H2O2 in culture medium was quantified (Mann-Whitney; α=5%) and colour change (ΔE) of enamel was analysed after 3 sessions (Tukey's test; α=5%). Cell viability reduction, H2O2 diffusion, cell morphology alteration, oxidative stress, and cell membrane damage occurred in a concentration-/time-dependent fashion. The cell viability reduction was significant in all groups for HDPCs and only for G2, G3, and G5 in MDPC-23 cells compared with G1. Significant cell viability and morphology recovery were observed in all groups at T2, except for G2 in HDPCs. The highest ΔE value was found in G2. However, all groups presented significant ΔE increases compared with G1. Shortening the contact time of a 35%-H2O2 gel for 5 min, or reducing its concentration to 17.5% and applying it for 45, 15, or 5 min produce gradual tooth colour change associated with reduced trans-enamel and trans-dentinal cytotoxicity to pulp cells. The experimental protocols tested in the present study provided significant tooth-bleaching improvement associated with decreased toxicity to pulp cells, which may be an interesting alternative to be tested in clinical situations intended to reduce tooth sensitivity and pulp damage. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Physical and Mechanical Properties of Cellulose Nanofibril Films from Bleached Eucalyptus Pulp by Endoglucanase Treatment and Microfluidization

    Science.gov (United States)

    Wangxia Wang; Ronald C. Sabo; Michael D. Mozuch; Phil Kersten; J. Y. Zhu; Yongcan Jin

    2015-01-01

    A GH5 hyperthermostable endoglucanase (Ph-GH5) from the archaeon Pyrococcus horikoshii and a commercial endoglucanase (FR) were used to treat bleached eucalyptus pulp (BEP) fibers to produce cellulose nanofibrils (CNF) and subsequently to CNF films. TEM imaging indicated that Ph-GH5 produced longer and more entangled CNF than FR with the same number...

  12. Gamma ray induced chromophore modification of softwood thermomechanical pulp

    International Nuclear Information System (INIS)

    Robert, S.; Daneault, C.; Viel, C.; Lepine, F.

    1992-01-01

    This study focuses on bleaching a softwood (black spruce, balsam fur) thermomechanical pulp with gamma rays. Gamma rays are known for their enormous penetrating power, along with their ionizing properties. They can generate highly energetic radicals capable of oxidizing lignin chromophores. The authors studied the influence of isopropyl alcohol, sodium borohydride, oxygen, hydrogen peroxide, nitrogen dioxide and water along with gamma ray irradiation of the pulps. The authors measured the optimal dose and dose rate, along with the influence of the radical scavengers like oxygen on the bleaching effect of gamma irradiated pulps. They observe various degrees of bleaching of these pulps. Evidence relates this bleaching to the generation of perhydroxyl anions upon irradiation of water. Also, they were able to pinpoint the influence of the dose rate on the rate of formation and disappearance of these perhydroxyl anions and their influence on bleaching kinetics. Stability toward photoyellowing, and photoyellowing's kinetic of papers from these pulps was also studied

  13. Influence of High Shear Dispersion on the Production of Cellulose Nanofibers by Ultrasound-Assisted TEMPO-Oxidation of Kraft Pulp

    Directory of Open Access Journals (Sweden)

    Claude Daneault

    2012-09-01

    Full Text Available Cellulose nanofibers can be produced using a combination of TEMPO, sodium bromide (NaBr and sodium hypochlorite, and mechanical dispersion. Recently, this process has been the subject of intensive investigation. However, studies on the aspects of mechanical treatment of this process remain marginal. The main objective of this study is to evaluate the high shear dispersion parameters (e.g., consistency, stator-rotor gap, recirculation rate and pH and determine their influences on nanocellulose production using ultrasound-assisted TEMPO-oxidation of Kraft pulp. All nanofiber gels produced in this study exhibited rheological behaviors known as shear thinning. From all the dispersion parameters, the following conditions were identified as optimal: 0.042 mm stator-rotor gap, 200 mL/min recycle rate, dispersion pH of 7 and a feed consistency of 2%. High quality cellulose gel could be produced under these conditions. This finding is surely of great interest for the pulp and paper industry.

  14. Pulp and paper from blue agave waste from tequila production.

    Science.gov (United States)

    Idarraga, G; Ramos, J; Zuñiga, V; Sahin, T; Young, R A

    1999-10-01

    Pulping of blue agave waste, from the production of tequila, was evaluated by both chemical and biomechanical pulping processes. Two conventional and two organosolv systems were used to pulp the agave waste under a standard set of conditions. The soda-ethanol process was superior in terms of delignification and pulp properties in comparison to the soda and ethanol organosolv processes for pulping of agave waste; however, the kraft process gave the best strength properties. In general, the strength of the agave waste pulps was rather poor in comparison to wood and other agro-based pulps; however, the tear strength was relatively high. This result is typical of poorly bonded sheets and may be due to the coarseness of the agave fibers and/or loss of hemicelluloses in the steaming process for the tequila production. Fungal treatment of the agave waste with Ceriporiopsis subvermispora reduced the energy consumption for mechanical refining but gave biomechanical pulps with inferior strength properties. The blue agave chemical pulps should be suitable for blending with softwood kraft pulps for publication grade paper.

  15. EFFECTS OF ALKALINE PRE-IMPREGNATION AND PULPING ON MALAYSIA CULTIVATED KENAF (HIBISCUS CANNABINUS

    Directory of Open Access Journals (Sweden)

    Lin Suan Ang

    2010-05-01

    Full Text Available This study was carried out to identify an appropriate alkaline pulping condition for Malaysia cultivated kenaf (Hibiscus cannabinus L.. The chemical composition of the kenaf bast and core fibers, and also whole stalk with different growing time were examined prior to pulping attempts. The results of various soda-AQ pulping showed that the degree of carbohydrate degradation and delignification increased with the increase of active alkali and cooking temperature, but decreased with the increase of liquor to material (L:M ratio. The most satisfactory properties of pulp and handsheets from bast could be attained by employing soda-AQ pulping with 19.4% active alkali, 0.10% AQ, and L:M ratio of 7:1 cooked for 2 hours at 160˚C. Besides, it was also found that a mild alkaline pre-impregnation prior pulping improved the pulp viscosity and handsheets’ strength properties, especially the tensile index and folding endurance effectively. Moreover, among the three alkaline pulping processes—kraft, kraft-AQ, and soda-AQ—the results of pulp and handsheet properties showed that the soda-AQ pulp was comparable or even slightly of higher quality than the kraft pulps. Between the unbeaten bast and core soda-AQ handsheets, the strength properties of the core were higher than the bast, as the thin-walled core fibers exhibited much better conformability than the thick-walled bast fibers.

  16. A utilização de perácidos na deslignificação e no branqueamento de polpas celulósicas The use of peracids in delignification and cellulose pulp bleaching

    Directory of Open Access Journals (Sweden)

    Lilian Borges Brasileiro

    2001-12-01

    Full Text Available Peracids are strong oxidant species and their use is being largely studied in the delignification and cellulose pulp bleaching. Some of them has already an industrial application, specially in non-conventional bleaching sequences like ECF (Elemental chlorine free and TCF (Totally chlorine free. This review presents the main aspects of the structure, properties, preparation and reaction of peracids (peracetic acid, peroxymonosulfuric acid and their mixture with lignin, specially for peracetic acid. Information about bleaching and delignification of wood pulps with peracids and the factors affecting its efficiency are also presented.

  17. Comparison of various pulping characteristic of Fraxinus angustifolia ...

    African Journals Online (AJOL)

    Handsheets made from different pulping methods were compared with each other for strength and optical properties. Strength properties were found to be higher for kraft and kraft + anthraquinone processes, while optical properties were found to be higher for cold soda and NSSC processes. Key words: Ash, Fraxinus ...

  18. High Selectivity Oxygen Delignification

    Energy Technology Data Exchange (ETDEWEB)

    Arthur J. Ragauskas

    2005-09-30

    yield and 4 cP in viscosity in comparison to high AA pulp for the oxygen delignification. This difference is also seen for high-kappa SW kraft pulps with an average improvement of {approx}3% in yield and 3 cP in viscosity for low AA high kappa number 50 pulp. Low AA hardwood kappa number 20 pulp had an average improvement of {approx}4% in yield and 6-12 cP in viscosity as compared to high AA pulp. Lower kraft cooking temperature (160 vs. 170 C) in combination with the medium AA provides a practical approach for integrating high kappa pulping of hardwoods (i.e., low rejects) with an advanced extended oxygen delignification stage. ECF pulp bleaching of low and high kappa kraft SW and HW pulps exhibit comparable optical and physical strength properties when bleached D(EPO)D.

  19. Kraft cooking of gamma irradiated wood, (2)

    International Nuclear Information System (INIS)

    Inaba, Masamitsu; Meshitsuka, Gyosuke; Ishizu, Atsushi; Nakano, Junzo

    1981-01-01

    Pre-irradiation of wood in alkaline aqueous ethanol increases kraft pulp yield by up to 1.2%, as already reported. In order to clarify the mechanism of the pulp yield gain, the behaviors of lignin and carbohydrates during pre-irradiation and cooking were investigated. The results are summarized as follows: 1) γ-Irradiation of guaiacylethane in alkaline aqueous ethanol produced 5-(1-hydroxyethyl)-guaicylethane, which is formed by radical coupling between α-hydroxyethyl radical from ethanol and guaiacylethane radical having an unpaired electron at C-5. 5,5'-Dehydrodiguaiacylethane, which may be a predominant product produced by γ-irradiation in the absence of ethanol, was also detected. 2) The yield of vanillin obtained by nitrobenzene oxidation of MWL decreased with an increase of γ-ray dosage. The presence of ethanol during γ-irradiation lessened the extent of this decrease and also the degradation of cellobiose. 3) Gel filtration of the products obtained by γ-irradiation of MWL and cellobiose in the presence of 14 C-ethanol showed the possible combination between ethanol and MWL or cellobiose. 4) Molecular weight distributions of kraft lignin obtained from pre-irradiated beech chips were compared with those obtained from unirradiated chips. This result shows that γ-irradiation in the presence of ethanol decreases the ability of lignin to condense during kraft cooking. (author)

  20. EFEITO DA QUALIDADE DA MADEIRA NO DESEMPENHO DA POLPAÇÃO KRAFT

    Directory of Open Access Journals (Sweden)

    Danila Morais de Carvalho

    2014-01-01

    Full Text Available The aim of this study was to evaluate the wood quality in the kraft pulping performance under two different pulping conditions at two delignification degrees based on results for the yield, brightness, viscosity, and k/ kappa corrected index. Eucalyptus wood (A, B, and C was analyzed about their physicochemical properties (basic and apparent density, insoluble and soluble lignin content, extractive content, ash and insoluble ash in hydrochloric acid and used for pulp production by modified kraft cooking, using two different pulping conditions: Condition I (PI - 16.5% effective alkali, 30% sulfidity, and 155º of cooking temperature; and Condition II (PII - 17.5% effective alkali, 32% sulfidity,and 147ºC cooking temperature. Both conditions were performed to kappa number 15.5 ± 0.5 and 18.0 ± 0.5. The following pulping parameters and pulp properties produced were evaluated: H factor, screened yield, viscosity, brightness, hexenuronic acid content, and the k/kappa corrected index. The A wood, which had lower extractives and lignin content in its constitution, as well as lower basic and apparent density when compared with B and C woods, showed good results for cooking parameters, especially the pulp produced at PII condition at kappa number 18.0 ± 0.5.Also, the A wood showed higher screened yield, brightness, and viscosity comparing to the other pulps produced. Those pulps produced with higher kappa number have lower k/kappa corrected index.

  1. Mechanical deconstruction of lignocellulose cell walls and their enzymatic saccharification

    Science.gov (United States)

    Ingrid C. Hoeger; Sandeep S. Nair; Arthur J. Ragauskas; Yulin Deng; Orlando J. Rojas; J.Y. Zhu

    2013-01-01

    Laboratory mechanical softwood pulps (MSP) and commercial bleached softwood kraft pulps (BSKP) were mechanically fibrillated by stone grinding with a SuperMassColloider®. The extent of fibrillation was evaluated by SEM imaging, water retention value (WRV) and cellulase adsorption. Both lignin content and mechanical treatment significantly affected deconstruction and...

  2. High alpha cellulose from fast growing species such as Lantana camara (linn) and Hibiscus cannabinus

    Energy Technology Data Exchange (ETDEWEB)

    Manavalan, R.; Mithal, B.M.; Anand, S.M.; Chawla, J.S.

    1980-01-01

    Prehydrolysis of L. camara and kenaf with H/sub 2/O at 165 degrees, and kraft cooking gave pulp in 28-40% yield, and permanganate number 8.5-12. Bleaching of the pulps from these species by CEHED sequence gave products in 26-41% yield, and with 83-90% brightness.

  3. Excess heat from kraft pulp mills: Trade-offs between internal and external use in the case of Sweden-Part 2: Results for future energy market scenarios

    International Nuclear Information System (INIS)

    Joensson, Johanna; Svensson, Inger-Lise; Berntsson, Thore; Moshfegh, Bahram

    2008-01-01

    In this paper the trade-off between internal and external use of excess heat from a kraft pulp mill is investigated for four different future energy market scenarios. The work follows the methodology described in Svensson et al. [2008. Excess heat from kraft pulp mills: trade-offs between internal and external use in the case of Sweden-Part 1: methodology. Energy Policy, submitted for publication], where a systematic approach is proposed for investigating the potential for profitable excess heat cooperation. The trade-off is analyzed by economic optimization of an energy system model consisting of a pulp mill and an energy company (ECO). In the model, investments can be made, which increase the system's energy efficiency by utilization of the mill's excess heat, as well as investments that increase the electricity production. The results show that the trade-off depends on energy market prices, the district heating demand and the type of existing heat production. From an economic point of view, external use of the excess heat is preferred for all investigated energy market scenarios if the mill is studied together with an ECO with a small heat load. For the cases with medium or large district heating loads, the optimal use of excess heat varies with the energy market price scenarios. However, from a CO 2 emissions perspective, external use is preferred, giving the largest reduction of global emissions in most cases

  4. RELATIONSHIP BETWEEN CRYSTALLINE STRUCTURE AND OPTICAL PROPERTIES OF WHEAT (Triticum aestevum L. STRAW SODA-OXYGEN PULP

    Directory of Open Access Journals (Sweden)

    Esat Gümüşkaya

    2003-04-01

    Full Text Available In this study; pulp was produced with soda-oxygen process by using wheat (Triticum aestevum L. straw as raw material and this pulp bleached with hypocholoride (H and peroxyde (P stages. It was found that crystalline properties of unbleached and bleached pulp samples increased by removing amorphous components. In addition, paper sheets made from unbleached and bleached soda-oxygen pulp and determined their optical properties. Consequently; while crystalline properties of pulp samples was rising with HP bleaching, it was determined that optical properties of paper sheets improved with bleaching.

  5. Removal of inhibitors from pre-hydrolysis liquor of kraft-based dissolving pulp production process using adsorption and flocculation processes.

    Science.gov (United States)

    Liu, Xin; Fatehi, Pedram; Ni, Yonghao

    2012-07-01

    A process for removing inhibitors from pre-hydrolysis liquor (PHL) of a kraft-based dissolving pulp production process by adsorption and flocculation, and the characteristics of this process were studied. In this process, industrially produced PHL was treated with unmodified and oxidized activated carbon as an absorbent and polydiallyldimethylammonium chloride (PDADMAC) as a flocculant. The overall removal of lignin and furfural in the developed process was 83.3% and 100%, respectively, while that of hemicelluloses was 32.7%. These results confirmed that the developed process can remove inhibitors from PHL prior to producing value-added products, e.g. ethanol and xylitol via fermentation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Branqueamento de polpa de eucalipto com sequências curtas

    Directory of Open Access Journals (Sweden)

    Flaviana Reis Milagres

    2011-01-01

    Full Text Available Eucalyptus spp kraft pulp, due to its high content of hexenuronic acids, is quite easy to bleach. Therefore, investigations have been made attempting to decrease the number of stages in the bleaching process in order to minimize capital costs. This study focused on the evaluation of short ECF (Elemental Chlorine Free and TCF (Totally Chlorine Free sequences for bleaching oxygen delignified Eucalyptus spp. kraft pulp to 90% ISO brightness: PMoDP (Molybdenum catalyzed acid peroxide, chlorine dioxide and hydrogen peroxide, PMoD/P (Molybdenum catalyzed acid peroxide, chlorine dioxide and hydrogen peroxide, without washing PMoD(PO (Molybdenum catalyzed acid peroxide, chlorine dioxide and pressurized peroxide, D(EPODP (chlorine dioxide, extraction oxidative with oxygen and peroxide, chlorine dioxide and hydrogen peroxide, PMoQ(PO (Molybdenum catalyzed acid peroxide, DTPA and pressurized peroxide, and XPMoQ(PO (Enzyme, molybdenum catalyzed acid peroxide, DTPA and pressurized peroxide. Uncommon pulp treatments, such as molybdenum catalyzed acid peroxide (PMo and xylanase (X bleaching stages, were used. Among the ECF alternatives, the two-stage PMoD/P sequence proved highly cost-effective without affecting pulp quality in relation to the traditional D(EPODP sequence and produced better quality effluent in relation to the reference. However, a four stage sequence, XPMoQ(PO, was required to achieve full brightness using the TCF technology. This sequence was highly cost-effective although it only produced pulp of acceptable quality.

  7. Efeito do teor de lignina da madeira de Eucalyptus globulus Labill. no desempenho da polpação kraft

    Directory of Open Access Journals (Sweden)

    Gabriel Valim Cardoso

    2011-01-01

    Full Text Available In this research, it was analyzed the lignin content effect of Eucalyptus globulus Labill. wood in kraft pulping optimization. Seventy-two laboratory cooking were made with wood chips obtained from six Eucalyptus globulus trees selected from a group of 50 trees. The wood chips from three trees with the lowest lignin content, with average 20.53%, were mixed proportionally based on the tree weights, obtaining the sample of low lignin content wood. The same was made to obtain the sample for wood chips with the highest lignin content, with average 23.02%. The two lignin levels were statistically different. The two wood samples had basic densities statistically not different. Using three maximum temperatures levels (160, 165 and 170ºC, and three active alkali charged (17, 18.5 and 20%, the wood chips were converted to kraft pulps. The pulps were then characterized to analyze the influence of the distinct treatments employed in the cooking on their properties. The effect of the cooking conditions was expressed by mathematical models in order to determine the optimum points for each of the evaluated properties. The optimization process indicated maximum temperature of 168ºC, and active alkali of 19%, for maximum kraft pulping yield to achieve kappa number 18; this result was for woods with low lignin content. For woods containing the high lignin content, the optimization showed maximum cooking temperature of 169ºC and active alkali of 19% for kappa number of 18. The average reduction of 2.49% in wood lignin content resulted a correspondent gain of 2.2% in the kraft yield (o.d. basis and a reduction on the active alkali charge of 1.2% (o.d. basis to achieve kappa numbers from 16 to 19, preserving pulp properties. If the option is to work with kappa number 19 instead of 16, the gain in kraft yield is approximately 2%. Therefore, when working with low lignin content wood and kappa number 19 instead of 16, a substantial gain of approximately 4.2% is

  8. Fiber length and pulping characteristics of switchgrass, alfalfa stems, hybrid poplar and willow biomasses.

    Science.gov (United States)

    Ai, Jun; Tschirner, Ulrike

    2010-01-01

    Switchgrass (Panicum virgatum), alfalfa stems (Medicago sativa), second year growth hybrid poplar (Populus) and willow (Salix spp.) were examined to determine fiber characteristics, pulping behavior and paper properties. Alfalfa stems and switchgrass both showed length weighted average fiber length (LWW) of 0.78 mm, a very narrow fiber length distribution and high fines content. Willow and hybrid poplar have lower fines content but a very low average fiber length (0.42 and 0.48 mm LWW). In addition, the four biomass species showed distinctly different chemical compositions. Switchgrass was defibered successfully using Soda and Soda Anthraquinone (AQ) pulping and demonstrated good paper properties. Both fast-growing wood species pulped well using the Kraft process, and showed acceptable tensile strength, but low tear strength. Alfalfa stems reacted very poorly to Soda and Soda AQ pulping but responded well to Kraft and Kraft AQ. Pulps with tensile and tear strength considerably higher than those found for commercial aspen pulps were observed for alfalfa. All four biomass species examined demonstrated low pulp yield. The highest yields were obtained with poplar and switchgrass (around 43%). Considering the short fibers and low yields, all four biomass types will likely only be used in paper manufacturing if they offer considerable economic advantage over traditional pulp wood.

  9. Optimization of pulping conditions of abaca. An alternative raw material for producing cellulose pulp.

    Science.gov (United States)

    Jiménez, L; Ramos, E; Rodríguez, A; De la Torre, M J; Ferrer, J L

    2005-06-01

    The influence of temperature (150-170 degrees C), pulping time (15-45 min) and soda concentration (5-10%) in the pulping of abaca on the yield, kappa, viscosity, breaking length, stretch and tear index of pulp and paper sheets, was studied. Using a factorial design to identify the optimum operating conditions, equations relating the dependent variables to the operational variables of the pulping process were derived that reproduced the former with errors lower than 25%. Using a high temperature, and a medium time and soda concentration, led to pulp that was difficult to bleach (kappa 28.34) but provided acceptable strength-related properties (breaking length 4728 m; stretch 4.76%; tear index 18.25 mN m2/g), with good yield (77.33%) and potential savings on capital equipment costs. Obtaining pulp amenable to bleaching would entail using more drastic conditions than those employed in this work.

  10. Integrating black liquor gasification with pulping - Process simulation, economics and potential benefits

    Science.gov (United States)

    Lindstrom, Erik Vilhelm Mathias

    Gasification of black liquor could drastically increase the flexibility and improve the profit potential of a mature industry. The completed work was focused on research around the economics and benefits of its implementation, utilizing laboratory pulping experiments and process simulation. The separation of sodium and sulfur achieved through gasification of recovered black liquor, can be utilized in processes like modified continuous cooking, split sulfidity and green liquor pretreatment pulping, and polysulfide-anthraquinone pulping, to improve pulp yield and properties. Laboratory pulping protocols have been developed for these modified pulping technologies and different process options evaluated. The process simulation work around BLG has led to the development of a WinGEMS module for the low temperature MTCI steam reforming process, and case studies comparing a simulated conventional kraft process to different process options built around the implementation of a BLG unit operation into the kraft recovery cycle. Pulp yield increases of 1-3% points with improved product quality, and the potential for capital and operating cost savings relative to the conventional kraft process have been demonstrated. Process simulation work has shown that the net variable operating cost for a pulping process using BLGCC is highly dependent on the cost of lime kiln fuel and the selling price of green power to the grid. Under the assumptions taken in the performed case study, the BLGCC process combined with split sulfidity or PSAQ pulping operations had net variable operating cost 2-4% greater than the kraft reference. The influence of the sales price of power to the grid is the most significant cost factor. If a sales price increase to 6 ¢/KWh for green power could be achieved, cost savings of about $40/ODtP could be realized in all investigated BLG processes. Other alternatives to improve the process economics around BLG would be to modify or eliminate the lime kiln unit

  11. In-office tooth bleaching with 38% hydrogen peroxide promotes moderate/severe pulp inflammation and production of ll-1β, TNF-β, GPX, FGF-2 and osteocalcin in rats.

    Science.gov (United States)

    Silva-Costa, Renata Suellen Galvão da; Ribeiro, Andressa Eveline de Lima; Assunção, Isauremi Vieira de; Araújo Júnior, Raimundo Fernandes de; Araújo, Aurigena Antunes de; Guerra, Gerlane Coelho Bernardo; Borges, Boniek Castillo Dutra

    2018-06-11

    To study the intensity of inflammatory infiltrate and production of interleukin-1β (ll-1β), tumor necrosis factor-β (TNF-β), fibroblast growth factor-2 (FGF-2), glutathione peroxidase (GPX), and osteocalcin in response to in-office tooth bleaching in rats. Twenty male Wistar rats were randomized into four groups (n=5) according to the received treatment (tooth bleaching or no treatment - control) and the period of euthanasia after treatment (24 h or 10 days). We performed tooth bleaching using a 38% hydrogen peroxide gel on maxillary and mandibular incisors. After euthanasia, incisors (20 per group) were processed for histological analysis, immunohistochemistry staining of ll-1β, TNF-β, FGF-2 and GPX and osteocalcin by immunofluorescence. We analyzed data using the Mann-Whitney and Kruskal-Wallis/Dunn tests (p<0.05). The bleached groups presented statistically significant differences regarding the pulp inflammation stage compared with the control groups. Bleached teeth showed moderate/severe inflammatory infiltrate and control groups presented absent inflammatory cells or a negligible number of mononuclear cells (p<0.001) at two times (24 h and 10 days). There was strong staining for ll-1β, TNF-β, and GPX in bleached groups at 24 h and strong staining for ll-1β, TNF-β, GPX and FGF-2 at 10 days. After 10 days of tooth bleaching, the bleached group showed a statistically superior amount of osteocalcin than the other groups (p<0.01). Tooth bleaching with 38% hydrogen peroxide causes severe pulp inflammation, but characteristics of tissue repair after 10 days.

  12. PROCESS OPTIMIZATION OF TETRA ACETYL ETHYLENE DIAMINE ACTIVATED HYDROGEN PEROXIDE BLEACHING OF POPULUS NIGRA CTMP

    OpenAIRE

    Qiang Zhao; Junwen Pu; Shulei Mao; Guibo Qi

    2010-01-01

    To enhance the bleaching efficiency, the activator of tetra acetyl ethylene diamine (TAED) was used in conventional H2O2 bleaching. The H2O2/TAED bleaching system can accelerate the reaction rate and shorten bleaching time at relative low temperature, which can reduce the production cost. In this research, the process with hydrogen peroxide activated by TAED bleaching of Populus nigra chemi-thermo mechanical pulp was optimized. Suitable bleaching conditions were confirmed as follows: pulp con...

  13. Properties of Enzyme Pretreated Wikstroemia sikokiana and Broussonetia papyrifera Bast Fiber Pulps

    Directory of Open Access Journals (Sweden)

    Lang-Dong Lin

    2015-04-01

    Full Text Available Xylanase, pectinase complex, and BL11 pectinase were employed for the pretreatment of gampi and paper mulberry bast fiber pulps prior to chlorine dioxide bleaching. The bleaching efficiencies of the pulps with different enzymatic pretreatments were investigated. Accelerated aging by heat-humidity treatment was also conducted to evaluate yellowing phenomena and to estimate the prevention of brightness reversion (brightness retention by enzymatic pretreatment. The order of active chlorine required with respect to pretreatment was pectinase complex > xylanase > BL11 pectinase for soda and soda/oxalate gampi pulps and pectinase complex > BL11 pectinase > xylanase for soda and soda/oxalate paper mulberry pulps. Higher brightness retention values were observed for soda/oxalate pulps compared to soda pulps. The brightness retention levels for gampi pulps and mulberry pulps after ClO2 bleaching with enzymatic pretreatment were higher than the levels of ClO2 and NaClO bleaching pulps. Enzymatic treatments were thus able to reduce the usage of ClO2 and to assist in producing photo-stable paper materials for art and artifact-repairing applications. Thus, enzymatic pretreatment of the pulp has the potential to meet world trends and environmental sustainability for pulp and paper industries.

  14. INFLUENCE OF BLEACHING WITH OZONE AND PEROXIDO OF HYDROGEN IN THE YIELD AND QUALITY OF SECONDARY FIBERS

    Directory of Open Access Journals (Sweden)

    Gustavo Ventorim

    2010-08-01

    Full Text Available In this study, Total Chlorine Free (TCF bleaching processes were evaluated for bleaching a secondary fiber of different origens. The samples were bleached to a target brightness of 78 % ISO. The results were interpreted on the basis of chemical cost to reach the target brightness, bleaching yield and bleached pulp quality as measured by viscosity, fluorescence and b* color coordinate. The ozone stage was responsible for improve TCF bleaching performance. The pulp bleached by sequences contained a ozone stage followed by chelation, without interstage washing (ZQ, and a final hydrogen peroxide stage unpressurized (P or pressurized with oxygen (PO, designed as (ZQ(PO showed good results. These sequences decreased pulp b* coordinate significantly and fluorescence slightly. For  all three bleaching processes, it was determined that process yield is negatively affected by hot alkaline stages such as oxygen, O, peroxide, P, and peroxide pressurized with oxygen, (PO and also for the origin of the pulps of secondary fibers.

  15. Biobutanol production by Clostridium acetobutylicum using xylose recovered from birch Kraft black liquor.

    Science.gov (United States)

    Kudahettige-Nilsson, Rasika L; Helmerius, Jonas; Nilsson, Robert T; Sjöblom, Magnus; Hodge, David B; Rova, Ulrika

    2015-01-01

    Acetone-butanol-ethanol (ABE) fermentation was studied using acid-hydrolyzed xylan recovered from hardwood Kraft black liquor by CO2 acidification as the only carbon source. Detoxification of hydrolyzate using activated carbon was conducted to evaluate the impact of inhibitor removal and fermentation. Xylose hydrolysis yields as high as 18.4% were demonstrated at the highest severity hydrolysis condition. Detoxification using active carbon was effective for removal of both phenolics (76-81%) and HMF (38-52%). Batch fermentation of the hydrolyzate and semi-defined P2 media resulted in a total solvent yield of 0.12-0.13g/g and 0.34g/g, corresponding to a butanol concentration of 1.8-2.1g/L and 7.3g/L respectively. This work is the first study of a process for the production of a biologically-derived biofuel from hemicelluloses solubilized during Kraft pulping and demonstrates the feasibility of utilizing xylan recovered directly from industrial Kraft pulping liquors as a feedstock for biological production of biofuels such as butanol. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  16. 40 CFR 63.445 - Standards for the bleaching system.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Standards for the bleaching system. 63... Standards for Hazardous Air Pollutants from the Pulp and Paper Industry § 63.445 Standards for the bleaching system. (a) Each bleaching system that does not use any chlorine or chlorinated compounds for bleaching...

  17. Rice straw pulp obtained by using various methods.

    Science.gov (United States)

    Rodríguez, Alejandro; Moral, Ana; Serrano, Luis; Labidi, Jalel; Jiménez, Luis

    2008-05-01

    Rice straw was used as an alternative raw material to obtain cellulosics pulps. Pulping was done by using classics reagents as soda (with anthraquinone and parabenzoquinone as aditives), potassium hydroxide and Kraft process. The holocellulose, alpha-cellulose and lignin contents of rice straw (viz. 60.7, 41.2 and 21.9 wt%, respectively) are similar to those of some woody raw materials such as pine and eucalyptus, and various non-wood materials including olive tree prunings, wheat straw and sunflower stalks. Pulping tests were conducted by using soda, soda and anthraquinone at 1 wt%, soda and parabenzoquinone at 1 wt%, potassium hydroxide and sodium sulphate (Kraft process) under two different sets of operating conditions, namely: (a) a 10 wt% reagent concentration, 170 degrees C and 60 min; and (b) 15 wt% reagent, 180 degrees C and 90 min. The solid/liquid ratio was 6 in both cases. Paper sheets made from pulp extracted by cooking with soda (15 wt%) and AQ (1 wt%) at 180 degrees C and 90 min pulp exhibit the best drainage index, breaking length, stretch and burst index (viz. 23 degrees SR, 3494 m, 3.34% and 2.51 kN/g, respectively).

  18. In-office tooth bleaching with 38% hydrogen peroxide promotes moderate/severe pulp inflammation and production of ll-1β, TNF-β, GPX, FGF-2 and osteocalcin in rats

    Directory of Open Access Journals (Sweden)

    Renata Suellen Galvão da Silva-Costa

    2018-06-01

    Full Text Available Abstract Objectives: To study the intensity of inflammatory infiltrate and production of interleukin-1β (ll-1β, tumor necrosis factor-β (TNF-β, fibroblast growth factor-2 (FGF-2, glutathione peroxidase (GPX, and osteocalcin in response to in-office tooth bleaching in rats. Material and Methods: Twenty male Wistar rats were randomized into four groups (n=5 according to the received treatment (tooth bleaching or no treatment - control and the period of euthanasia after treatment (24 h or 10 days. We performed tooth bleaching using a 38% hydrogen peroxide gel on maxillary and mandibular incisors. After euthanasia, incisors (20 per group were processed for histological analysis, immunohistochemistry staining of ll-1β, TNF-β, FGF-2 and GPX and osteocalcin by immunofluorescence. We analyzed data using the Mann-Whitney and Kruskal-Wallis/Dunn tests (p<0.05. Results: The bleached groups presented statistically significant differences regarding the pulp inflammation stage compared with the control groups. Bleached teeth showed moderate/severe inflammatory infiltrate and control groups presented absent inflammatory cells or a negligible number of mononuclear cells (p<0.001 at two times (24 h and 10 days. There was strong staining for ll-1β, TNF-β, and GPX in bleached groups at 24 h and strong staining for ll-1β, TNF-β, GPX and FGF-2 at 10 days. After 10 days of tooth bleaching, the bleached group showed a statistically superior amount of osteocalcin than the other groups (p<0.01. Conclusions: Tooth bleaching with 38% hydrogen peroxide causes severe pulp inflammation, but characteristics of tissue repair after 10 days.

  19. Chemi-thermomechanical pulping of para rubber waste wood

    Energy Technology Data Exchange (ETDEWEB)

    Kubo, T.; Hosokawa, J.; Kobayashi, T.; Kobayashi, Y.

    1981-01-01

    The addition of NaOH to Na/sub 2/SO/sub 3/-treated waste wood chips (Hevea brasiliensis) increased long fiber fraction, Klason lignin content and bulk density, improved breaking length and tear factor, and decreased energy consumption in refining and brightness of resulting chemithermomechanical pulp. Lowering in brightness by alkali treatment was recovered by H/sub 2/O/sub 2/ bleaching, and bleaching with 8% H/sub 2/O/sub 2/ on pulp gave pulp with 61.3% brightness.

  20. Life cycle greenhouse gases and non-renewable energy benefits of kraft black liquor recovery

    International Nuclear Information System (INIS)

    Gaudreault, Caroline; Malmberg, Barry; Upton, Brad; Miner, Reid

    2012-01-01

    The life cycle greenhouse gas (GHG) and fossil fuel benefits of black liquor recovery are analyzed. These benefits are due to the production of energy that can be used in the pulping process or sold, and the recovery of the pulping chemicals that would otherwise need to be produced from other resources. The fossil GHG emissions and non-renewable energy consumption of using black liquor in the kraft recovery system are approximately 90% lower than those for a comparable fossil fuel-based system. Across all scenarios, the systems relying on black liquor solids achieve a median reduction of approximately 140 kg CO 2 eq./GJ of energy produced, compared to the systems relying on fossil fuels to provide the same energy and pulping chemical production functions. The benefits attributable to the recovery of pulping chemicals vary from 44% to 75% of the total benefit. Applied to the total production of kraft pulp in the U.S., the avoided emissions are equivalent to the total Scopes 1 and 2 emissions from the entire U.S. forest products industry. These results do not depend on the accounting method for biogenic carbon (because biogenic CO 2 emissions are the same for the systems compared) and the results are valid across a range of assumptions about the displaced fossil fuel, the GHG-intensity of the electricity grid, the fossil fuels used in the lime kiln, and the level of cogeneration at pulp and paper mills. The benefits occur without affecting the amount of wood harvested or the amount of chemical pulp produced. -- Highlights: ► Black liquor, a by-product of kraft pulping, represents about half of the energy used in the paper industry. ► The greenhouse gases (GHG) benefits of black liquor recovery compared to an equivalent fossil fuel system were analyzed. ► The GHG emissions of the black liquor system are approximately 90% lower than those for the fossil fuel system. ► The benefits from the recovery of the chemicals vary from 44% to 75% of the total benefit.

  1. Mineral phases of green liquor dregs, slaker grits, lime mud and wood ash of a Kraft pulp and paper mill

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Fernanda Machado [Laboratorio de Quimica Mineral Aplicada, Departamento de Quimica-UFPR, Universidade Federal do Parana (UFPR), CP 19081, CEP 81531990, Curitiba-PR (Brazil); Munhoz Martins, Joaniel [Laboratorio de Analise de Minerais e Rochas (LAMIR-UFPR) (Brazil); Ferracin, Luiz Carlos [Laboratorio Quimico da Votorantin Cimentos (Brazil); Cunha, Carlos Jorge da [Laboratorio de Quimica Mineral Aplicada, Departamento de Quimica-UFPR, Universidade Federal do Parana (UFPR), CP 19081, CEP 81531990, Curitiba-PR (Brazil)]. E-mail: cjdcunha@quimica.ufpr.br

    2007-08-17

    Four residues generated in a Kraft, pulp and paper plant, were characterized by X-ray fluorescence spectroscopy (XFA), powder X-ray diffraction (XRD), thermogravimmetric analysis (TG) and Fourier transform infrared spectroscopy (FTIR). A quantitative phase composition model, that accounts for the observed data and for the physico-chemical conditions of formation, was postulated for each material. Emphasis was given on the identification of the mineral components of each material. The green liquor dregs and the lime mud contain Calcite and Gipsite. The slaker grits contains Calcite, Portlandite, Pirssonite, Larnite and Brucite. The Calcite phase, present in the dregs and in the lime mud, has small amounts of magnesium replacing calcium. The wood ash contains Quartz as the major crystalline mineral phase.

  2. Mineral phases of green liquor dregs, slaker grits, lime mud and wood ash of a Kraft pulp and paper mill

    International Nuclear Information System (INIS)

    Martins, Fernanda Machado; Munhoz Martins, Joaniel; Ferracin, Luiz Carlos; Cunha, Carlos Jorge da

    2007-01-01

    Four residues generated in a Kraft, pulp and paper plant, were characterized by X-ray fluorescence spectroscopy (XFA), powder X-ray diffraction (XRD), thermogravimmetric analysis (TG) and Fourier transform infrared spectroscopy (FTIR). A quantitative phase composition model, that accounts for the observed data and for the physico-chemical conditions of formation, was postulated for each material. Emphasis was given on the identification of the mineral components of each material. The green liquor dregs and the lime mud contain Calcite and Gipsite. The slaker grits contains Calcite, Portlandite, Pirssonite, Larnite and Brucite. The Calcite phase, present in the dregs and in the lime mud, has small amounts of magnesium replacing calcium. The wood ash contains Quartz as the major crystalline mineral phase

  3. Isolation and characterization of lignocellulose nanofibers from different wheat straw pulps.

    Science.gov (United States)

    Sánchez, Rafael; Espinosa, Eduardo; Domínguez-Robles, Juan; Loaiza, Javier Mauricio; Rodríguez, Alejandro

    2016-11-01

    Wheat straw was cooked under different pulping processes: Soda (100°C, 7% NaOH, 150min), Kraft (170°C, 16% alkalinity, 25% sulfidity, 40min) and Organosolv (210°C, 60% ethanol, 60min). Once the pulps were obtained, lignocellulose nanofibers (LCNF) were isolated by mechanical process and TEMPO-mediated oxidation followed by a high pressure homogenization. After pulping process, the different pulps were characterized and its chemical composition was determined. The pulps characterization indicates that the Soda process is the process that, despite producing less delignification, retains much of the hemicelluloses in the pulp, being this content a key factor in the nanofibrillation process. Regarding the LCNF obtained by mechanical process, those nanofibers isolated from Organosolv wheat pulp (OWP) and Kraft wheat pulp (KWP) show low values for nanofibrillation yield, specific surface area and greater diameter. However, those nanofibers isolated from Soda wheat pulp (SWP) reach much higher values for these parameters and presents a diameter of 14nm, smaller than those obtained by TEMPO-mediated oxidation from OWP. Smaller diameters are generally obtained in TEMPO-oxidized LCNF. This work concludes that the lignin content does not affect greatly to obtain LCNF as does the hemicellulose content, so it is accurate to use a soft pulping process. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. PEMUTIHAN PULP DENGAN HIDROGEN PEROKSIDA

    Directory of Open Access Journals (Sweden)

    Ahmad M. Fuadi

    2012-01-01

    Full Text Available The use of bleaching agent has increased as the result of increasing of paper consumption. The conventional bleaching agent that commonly used is material containing of chlorine. This material is not environmentally friendly and should be replaced by environmentally benign chemical, such as H2O2. About 40 gram of dry Akasia pulp was mixed with 600 ml of distilled water was put into plastic bag heated in a water bath. When the temperature reached 630C, a solution of 4 % of H2O2 and distilled water was added to obtain 5 % consistency. This mixture was put into water bath and was heated for 2 hours. The same procedure was conducted with various concentration of H2O2, time and pH. At the end of the process, the pulp was dewatered and washed. The filtrate obtained from the initial dewatering was used to determine the residual of H2O2. The pulp was analyzed to determine brightness, fiber strength and kappa number. The maximum achievement of brightness was 62,1 % ISO, 6.86 of kappa number and 1.02 kg/15 mm of fiber strength, which are reached at16 % of the use of H2O2, pH 11 and 5 hours of bleaching time. This achievement is similar to bleaching result by the additional of 4% H2O2. Inefficient usage of H2O2 was caused by some metal ions in the pulp which facilitate the decomposition of H2O2 to produce oxygen and water which has not effect on increasing the brightness. To improve the bleach ability of H2O2, initial treatment to remove metal ions from pulp should be done. Seiring dengan meningkatnya kebutuhan kertas, kebutuhan bahan pemutih juga mengalami kenaikan. Saat ini bahan pemutih yang banyak digunakan adalah senyawa yang mengandung khlor. Senyawa ini sangat tidak ramah lingkungan, oleh karena itu, perlu dicari bahan yang ramah lingkungan untuk menggantikannya. Salah satunya adalah hidrogen peroksida. Pulp dari pohon akasia sebanyak 40 gram kering dicampur dengan 600 ml aquadest dimasukkan dalam kantung plastik dipanaskan dalam water bath

  5. Characterization and sensory preference of fermented dairy beverages prepared with different concentrations of whey and araticum pulp

    Directory of Open Access Journals (Sweden)

    Alexsandra Valéria Sousa Costa de Lima

    2016-12-01

    Full Text Available The objective of this study was to develop a fermented dairy beverage flavored with araticum pulp, assess its physicochemical characteristics, microbiological quality, and sensory preference by the consumer. Araticum pulp was prepared using two different methods: with or without bleaching (50 ºC/5 minutes. Formulations of fermented dairy beverages consisting of whey (50%, standardized pasteurized milk (50%, and seven different concentrations of bleached araticum pulp (5.0, 7.5, 10.0, 12.5, 15.0, 17.5, and 20.0% w/v were prepared. In addition, seven formulations of fermented dairy beverage, without adding araticum pulp, and consisting of varying proportions of whey (40, 50, 60, 70, 80, 90, and 100% were developed. In all formulations, thickeners/stabilizers were added. All araticum pulp samples (with and without bleach and fermented dairy beverages (with and without araticum pulp were analyzed for the relevant physicochemical properties: pH, titratable acidity, acidity of pulp, acidity of fermented beverage, moisture, ash, fat, protein, crude fiber, ascorbic acid, carbohydrates, total solids, and caloric values. Microbiological counts of coliforms at 35 °C and 45 °C in the pulp and beverage, and molds and yeasts and Salmonella sp. in the pulp were obtained. Additionally, sensory analysis regarding preferences of the different fermented dairy beverage formulations was also performed. The araticum pulp samples without bleach, showed higher values of pH, moisture, protein, total fiber, and ascorbic acid, as compared to bleached pulp samples, while bleached araticum pulp showed higher values for other physicochemical parameters. Microbiological results showed that all pulps and fruit-dairy beverages were suitable for consumption. It was found that there was no significant consumer preference between different fermented beverage formulations, according to the different percentages of pulp. However, the formulations consisting of 40, 50, 60, and 70

  6. Combustion properties of kraft black liquors; Mustalipeaen koostumuksen vaikutus lipeaen poltto-ominaisuuksiin

    Energy Technology Data Exchange (ETDEWEB)

    Alen, R.; Siistonen, H.; Heikkinen, T.; Malkavaara, P. [Jyvaeskylae Univ. (Finland)

    1996-12-01

    The aim of this work is to study the combustion properties of kraft black liquors from modified cooking. Both the industrial and laboratory-made black liquors are included. In addition, changes in the combustion properties of the spent liquors obtained by mixing prior to combustion different chlorine-free bleach liquors with black liquor are studied. (author)

  7. China’s High-yield Pulp Sector and Its Carbon Dioxide Emission: Considering the Saved Standing Wood as an Increase of Carbon Storage

    Directory of Open Access Journals (Sweden)

    Yanhong Gao

    2014-11-01

    Full Text Available The production of high-yield pulp in China has increased significantly in recent years. The well-known advantages of this type of pulp include low production cost, high opacity, and good paper formation. In the context of state-of-the-art technologies, China’s high-yield pulping, which is dominated by the PRC-APMP (preconditioning refiner chemical treatment-alkaline peroxide mechanical pulping process, has a much higher energy input but a significantly lower wood consumption in comparison with the kraft pulping process. If the saved wood in the forest or plantation is considered as an increment of carbon storage, then the carbon dioxide emission from the production of high-yield pulp can be regarded as much lower than that of kraft pulp.

  8. Potassium hydroxide pulping of rice straw in biorefinery initiatives.

    Science.gov (United States)

    Jahan, M Sarwar; Haris, Fahmida; Rahman, M Mostafizur; Samaddar, Purabi Rani; Sutradhar, Shrikanta

    2016-11-01

    Rice straw is supposed to be one of the most important lignocellulosic raw materials for pulp mill in Asian countries. The major problem in rice straw pulping is silica. The present research is focused on the separation of silica from the black liquor of rice straw pulping by potassium hydroxide (KOH) and pulp evaluation. Optimum KOH pulping conditions of rice straw were alkali charge 12% as NaOH, cooking temperature 150°C for 2h and material to liquor ratio, 1:6. At this condition pulp yield was 42.4% with kappa number 10.3. KOH pulp bleached to 85% brightness by D0EpD1 bleaching sequences with ClO2 consumption of 25kg/ton of pulp. Silica and lignin were separated from the black liquor of KOH pulping. The amount of recovered silica, lignin and hemicelluloses were 10.4%, 8.4% and 13.0%. The papermaking properties of KOH pulp from rice straw were slightly better than those of corresponding NaOH pulp. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Method and apparatus for assaying wood pulp fibers

    Science.gov (United States)

    Gustafson, Richard [Bellevue, WA; Callis, James B [Seattle, WA; Mathews, Jeffrey D [Neenah, WI; Robinson, John [Issaquah, WA; Bruckner, Carsten A [San Mateo, CA; Suvamakich, Kuntinee [Seattle, WA

    2009-05-26

    Paper pulp is added to a stain solution. The stain solution and pulp fibers are mixed to form a slurry. Samples are removed from the slurry and are admixed with dilution water and a bleach. Then, the fibers are moved into a flow cell where they are subjected to a light source adapted to stimulate fluorescence from the stained pulp fiber. Before the fiber slurry enters the flow cell it is mixed with a dilution water of bleach to reduce background fluorescence. The fluorescent light is collimated and directed through a dichroic filter onto a fluorescence splitting dichroic filter.

  10. Bioconversion of oxygen-pretreated Kraft lignin to microbial lipid with oleaginous Rhodococcus opacus DSM 1069

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Zhen [Hunan Univ. Changsha (China); Zeng, Guangming [Hunan Univ. Changsha (China); Huang, Fang [Georgia Inst. of Technology, Atlanta, GA (United States); Kosa, Matyas [Georgia Inst. of Technology, Atlanta, GA (United States); Huang, Danlian [Hunan Univ. Changsha (China); Ragauskas, Arthur J. [Georgia Inst. of Technology, Atlanta, GA (United States); Univ. of Tennessee, Knoxville, TN (United States)

    2015-04-09

    Kraft lignin (KL) from black liquor is an abundantly available, inexpensive aromatic resource that is regarded as a low value compound by the pulp and paper industry, necessitating the development of new applications.

  11. Morphology and physical-chemical properties of celluloses obtained by different methods

    Science.gov (United States)

    Anpilova, A. Yu.; Mastalygina, E. E.; Mikhaylov, I. A.; Popov, A. A.; Kartasheva, Z. S.

    2017-12-01

    The morphology and structural characteristics of celluloses obtained by different methods were studied. The objects of the investigation are cellulose from pulp source, commercial celluloses produced by sodium and acid hydrolysis, laboratory produced cellulose from bleached birch kraft pulp, and cellulose obtained by thermooxidative catalytic treatment of maple leaves by peroxide. According to a complex analysis of cellulose characteristics, several types of celluloses were offered as modifying additives for polymers.

  12. Color Recovery Effect of Different Bleaching Systems on a ...

    African Journals Online (AJOL)

    2017-12-05

    Dec 5, 2017 ... KEYWORDS: Composite resin, discoloration, home bleaching, laser activated bleaching, office ... hexametaphosphate, which protect the teeth surface from .... exposure, saliva and other fluids diluting the staining .... Penetration of the pulp ... dentin permeability of carbamide peroxide and hydrogen peroxide.

  13. PENENTUAN KOMPOSISI OPTIMUM BUBURAN KERTAS KRAFT LINER 150 GSM MENGGUNAKAN METODE MIXTURE EXPERIMENT (Studi kasus: Pabrik Pulp & Paper PT.Z

    Directory of Open Access Journals (Sweden)

    Johnson Saragih

    2015-11-01

    Full Text Available Tujuan dari penelitian ini adalah bagaimana caranya memilih komposisi dari campuran buburan kertas sehingga posisi optimum dapat tercapai, dengan tercapainya komposisi optimum tersebut diharapkan dapat  meningkatkan kualitas kertas yang diproduksi.Adapun komposisi buburan kertas yang ingin dicapai adalah  konsistensi sebesar untuk campuran ,pada campuran satu, tingkat freeness sebesar pada campuran dua dan tingkat internal bonding sebesar   pada campuran tiga. Percobaan dilakukan dengan metoda mixture experiment untuk sampel percobaan buburan kertas sebanyak 500 gr. Titik percobaan dibangkitkan dengan software minitab sebanyak 14 titik percobaan.Adapun komposisi campuran yang optimal diperoleh untuk total campuran diperoleh sebesar 71.23 % ( 356.15 gr Waste Paper, 8.72% (43.55gr Pulp (NUKP, 3.54% (17.7 gr Air, 5.7%(28.5 gr Rosin, 3.29 % (16.4 gr Aluminium Sulfat ( Al2(SO43, dan 7.55 %(37.75gr Starch. Dengan komposisi tersebut akan dihasilkan produk yang memenuhi spesifikasi yang telah ditetapkan perusahaan. Berdasarkan pengukuran kapabilitas proses  campuran satu, pada kertas kraft liner 150 gsm di perusahaan  untuk tingkat konsistensi, adalah sebesar 0.47 dan setelah dilakukan percobaan yang optimal, berubah menjadi 1.11 berarti  terdapat peningkatan sebesar 136.7 %.Pada campuran dua untuk tingkat freeness adalah 0.45 berubah menjadi 1.14 berarti meningkat sebesar 153.3 %, sedangkan pada campuran tiga untuk tingkat internal bonding dari 0.55 berubah menjadi 1.15 berarti meningkat sebesar 109 %. Kata kunci: mixture experiment; konsistensi; freeness; internal bonding Abstract The aim of the research are how to choose composition from pulp paper mix, so that optimum position can be achieved, with the achievement of optimum composition, it can be expected to increase quality of paper production.While the pulp paper composition to achieve are consistency as big as for mixing on first mix, freeness level as big as on second mix and internal

  14. Understanding longitudinal wood fiber ultra-structure for producing cellulose nanofibrils using disk milling with diluted acid prehydrolysis

    Science.gov (United States)

    Yanlin Qin; Xueqing Qiu; Junyong Zhu

    2016-01-01

    Here we used dilute oxalic acid to pretreat a kraft bleached Eucalyptus pulp (BEP) fibers to facilitate mechanical fibrillation in producing cellulose nanofibrils using disk milling with substantial mechanical energy savings. We successfully applied a reaction kinetics based combined hydrolysis factor (CHFx) as a severity factor to quantitatively...

  15. Performance of Side-Streams from Eucalyptus Processing as Sources of Polysaccharides and Lignins by Kraft Delignification

    OpenAIRE

    Paula C. R. Pinto; Cátia Oliveira; Carina Costa; Alírio Rodrigues

    2016-01-01

    The performance of bark, branches, sawdust, forest biomass, and short-rotation eucalyptus in kraft delignification to produce polysaccharides and lignin is reported and discussed. A positive correlation was found between pulping severity required for delignification and lignin reactivity. Among all, branches feedstock is the best source of polysaccharides due to the high pulp yield (48-54%) with a satisfactory delignification degree. Branches lignin was characterized for the first time, evalu...

  16. Integrated production of nano-fibrillated cellulose and cellulosic biofuel (ethanol) by enzymatic fractionation of wood fibers

    Science.gov (United States)

    Junyong Zhu; Ronald Sabo; Xiaolin Luo

    2011-01-01

    This study demonstrates the feasibility of integrating the production of nano-fibrillated cellulose (NFC), a potentially highly valuable biomaterial, with sugar/biofuel (ethanol) from wood fibers. Commercial cellulase enzymes were used to fractionate the less recalcitrant amorphous cellulose from a bleached Kraft eucalyptus pulp, resulting in a highly crystalline and...

  17. determination of lipophilic extractives in ionic liquid extracts

    African Journals Online (AJOL)

    dell

    Chem. 9: 63-69. Freire CSR, Pinto PCR, Santiago AS,. Silvestre AJD, Evtuquin DV and Neto. CP 2006a Comparative study of lipophilic extractives of hardwoods and corresponding ECF bleached kraft pulps. BioResources. 1: 3-17. Freire CSR, Silvestre AJD and Neto CP. 2005. Lipophilic extractives in. Eucalyptus globulus.

  18. Strong and Optically Transparent Films Prepared Using Cellulosic Solid Residue Recovered from Cellulose Nanocrystals Production Waste Stream

    Science.gov (United States)

    Qianqian Wang; J.Y. Zhu; John M. Considine

    2013-01-01

    We used a new cellulosic material, cellulosic solid residue (CSR), to produce cellulose nanofibrils (CNF) for potential high value applications. Cellulose nanofibrils (CNF) were produced from CSR recovered from the hydrolysates (waste stream) of acid hydrolysis of a bleached Eucalyptus kraft pulp (BEP) to produce nanocrystals (CNC). Acid hydrolysis greatly facilitated...

  19. Effects of wet-pressing-induced fiber hornification on enzymatic saccharification of lignocelluloses

    Science.gov (United States)

    X.L. Luo; Junyong Zhu; Roland Gleisner; H.Y. Zhan

    2011-01-01

    This article reports the effect of wet-pressing-induced fiber hornification on enzymatic saccharification of lignocelluloses. A wet cellulosic substrate of bleached kraft eucalyptus pulp and two wet sulfite-pretreated lignocellulosic substrates of aspen and lodgepole pine were pressed to various moisture (solids) contents by variation of pressing pressure and pressing...

  20. ANTHRAQUINONE ADDITION IN THE ALKALINE PULPING OF Eucalyptus saligna

    Directory of Open Access Journals (Sweden)

    Lúcia Helena Jerônimo

    2009-10-01

    Full Text Available The present work evaluated different alkaline pulping conditions for Eucalyptus saligna wood. The objective was to evaluate the influence of the anthraquinone (AQ on the reduction of the total reduced sulfur (TRS in the aerial emissions, by reducing the sulfidity. The experiment consisted of 8 cooking with active alkali varying from  19 to 21%, sulfidity from  0 to 20% and anthraquinone from 0 to 0.1%, aiming to obtain  kappa numbers in the range 15.5±1.5. The H factor was used to control the relation time/temperature along cooking. The addition of anthraquinone increased the delignification rate allowing sulfidity reduction. The kraft/AQ pulping with sulfidities of 5 and 10% presented satisfactory results, making it possible the replacement of conventional kraft cooking, giving a reduction in process sulfidity without harms in pulping. In spite of a slightly lower performance, the soda/AQ cooking has potential to be used where the smell is a critical problem in the industrial operation.

  1. Tooth Whitening And Temperature Rise With Two Bleaching Activation Methods

    International Nuclear Information System (INIS)

    Abu-ElMagd, D. M.; El-Sayad, I. I.; Abd El-Gawad, L. M.

    2009-01-01

    To measure the tooth whitening and the surface and Intrapulpal temperature increase in vitro on freshly extracted upper human central incisors after chemical, Zoom AP light and diode laser activated bleaching. Thirty caries-free upper human incisors were selected. Teeth were divided into three equal groups according to the methods of activation of the bleaching agent (n = 10). A whitening gel containing hydrogen peroxide was applied to the buccal surface of all teeth. Group I was bleached using chemically activated hydrogen peroxide gel, for three applications of 15 min each. Group II was bleached with high intensity advanced power Zoom activation light (Zoom AP), for three applications of 15 min each. Group III was bleached with diode laser activation technique, where the teeth were irradiated with 2 Watt diode laser for three applications of 30 sec each. The whitening degree was assessed using an image analysis system, while temperature rise was recorded using a thermocouple on the external tooth surface and Intrapulpal. The degree of whitening increased significantly in all groups. However, the percentage of whitening was not statistically significantly different between the three groups. In addition, group II showed statistically significant higher mean rise in both surface and pulp temperatures than group I and group III. Chemical bleaching produces the same whitening effect as Zoom AP light and laser, with no surface or pulpal temperature rise. Laser application is faster and produces less surface and pulp temperature increase than Zoom AP light. Diode laser used to activate bleaching gels is not considered dangerous to the vitality of dental pulp using power settings of 2 W.

  2. Dentin bond strength and nanoleakage of the adhesive interface after intracoronal bleaching.

    Science.gov (United States)

    Cavalli, Vanessa; Sebold, Maicon; Shinohara, Mirela Sanae; Pereira, Patrícia Nóbrega Rodrigues; Giannini, Marcelo

    2018-04-01

    This study evaluated dentin bond strength (BS) and nanoleakage of non- and pre-etched dentin immediately (T 0 ,), 7 days (T 7 ), and 14 days (T 14 ) after bleaching. Bovine incisors (150) were selected and half of them submitted to intrapulpal dentin etching (e). Non- and pre-etched dentin were subjected to the following (n = 15): no bleaching/control (C); 35% carbamide peroxide (CP); 35% hydrogen peroxide (35% HP); 25% hydrogen peroxide (25% HP); and sodium perborate (SP). Bleaching agents were applied to the pulp chamber four times within a 72-h interval. Afterwards, pulp chamber dentin was prepared for the BS test at different evaluation times (n = 5): T 0 , T 7 , and T 14 . Composite blocks were built on pulp chamber and sectioned in slices. Slices were reduced to an hour-glass shape with a cross-sectional area of 0.8 mm 2 and submitted to microtensile BS test. Two additional specimens for each group were prepared for nanoleakage evaluation by transmission electron microscopy (TEM). Results were analyzed by ANOVA (two-way) and Dunnett's test (p bleaching for both sound and pre-etched dentin (p bleached dentin increased for all groups, whereas the pre-etched SPe group presented BS similar to the Ce. Nanoleakage within the hybrid layer was perceptible immediately after bleaching, although a decrease in nanoleakage was observed for all groups at T 14 . Adhesive restorations should be performed 7-14 days after bleaching, according to the bleaching agent used. Intracoronal bleaching should be performed preferably with sodium perborate if previous dentin etching is applied. © 2018 Wiley Periodicals, Inc.

  3. Integrated Forest Products Refinery (IFPR)

    Energy Technology Data Exchange (ETDEWEB)

    van Heiningen, Adriaan R. P.

    2010-05-29

    about 1% (on pulp). By using the wet-end retention aid guar gum during the adsorption process at a charge of 0.5% on pulp the yield gain may be increased to about 5%. Unfortunately, most of this yield increase is lost during subsequent alkaline treatments in the pulp bleach plant. It was found that by performing the adsorption at alkaline conditions the adsorption loss during alkaline treatment in the bleach plant is mostly avoided. Thus a permanent adsorption yield of about 3 and 1.5% (on pulp) was obtained with addition of guar gum at a charge of 0.5 and 0.1% respectively during adsorption of GL hardwood extract on pre-extracted kraft pulp at optimal conditions of pH 11.5, 90 C for 60 minutes at 5% consistency. The beatability of the adsorbed kraft pulps was improved. Also, significant physical strength improvements were achieved. Further study is needed to determine whether the improvements in pulp yield and paper properties make this an economic IFPR concept. Application of the wood solids of a hot water extract of Acer rubrum wood strands as a substitute for polystyrene used for production of SMC maintained the water adsorption properties of the final product. Further work on the physical properties of the hemicellulose containing SMCs need to be completed to determine the potential of wood extracts for the production of partially renewable SMCs. The discovery of the “near-neutral” green liquor extraction process for hardwood was formed the basis for a commercial Integrated Biorefinery that will extract hemicelluloses from wood chips to make biofuels and other specialty chemicals. The pulp production process will be maintained as is proposed in the present researched IFBR concept. This Integrated Biorefinery will be constructed by Red Shield Acquisition LLC (RSA) at the Old Town kraft pulp mill in Maine. RSA in collaboration with the University of Maine will develop and commercialize the hemicellulose extraction process, the conversion of the hemicellulose

  4. Kinetic modeling of formic acid pulping of bagasse.

    Science.gov (United States)

    Tu, Qiliang; Fu, Shiyu; Zhan, Huaiyu; Chai, Xinsheng; Lucia, Lucian A

    2008-05-14

    Organic solvent or organosolv pulping processes are alternatives to soda or kraft pulping to delignify lignocellulosic materials for the production of paper pulp. Formic acid, a typical organosolv system, has been presently examined under atmospheric pressure to pulp bagasse fibers. It was shown that efficient bagasse pulping was achieved when the formic acid concentration was limited to 90% (v/v). A statistical kinetic model based on the experimental results for the delignification of bagasse during formic acid pulping was developed that can be described as follows: D (delignification) = 0.747 x C(formicacid) (1.688) x (1 - e(-0.05171t)), an equation that can be used to predict the lignin content in formic acid during the pulping process. The delignification of bagasse by 90% formic acid was almost completed after approximately 80 min, while extended pulping did not improve the delignification but tended to degrade the carbohydrates in bagasse, especially the hemicelluloses, which were rapidly hydrolyzed at the onset of pulping.

  5. Optimizing cellulose fibrillation for the production of cellulose nanofibrils by a disk grinder

    Science.gov (United States)

    Chuanshuang Hu; Yu Zhao; Kecheng Li; J.Y. Zhu; Roland Gleisner

    2015-01-01

    The fibrillation of a bleached kraft eucalyptus pulp was investigated by means of a laboratory-scale disk grinder for the production of cellulose nanofibrils (CNF), while the parameters disk rotating speed, solid loading, and fibrillation duration were varied. The cumulative energy consumption was monitored during fibrillation. The degree of polymerization (DP) and...

  6. Flax fibers as a raw material: How to bleach efficiently a non-woody plant to obtain high-quality pulp

    International Nuclear Information System (INIS)

    Fillat, Ursula; Pepio, Montserrat; Vidal, Teresa; Roncero, M. Blanca

    2010-01-01

    Fiber crops constitute a good alternative to wood fiber for manufacturing pulp and paper. In fact, fiber plants like flax surpass wood fiber in some technical respects and also in the environmental benignity of their processing. In this work, flax fiber was subjected to environmentally friendly bleaching sequences in order to obtain a high-quality pulp. The totally chlorine-free sequences (TCF) used for this purpose (LE and LRE) included an enzyme treatment with laccase in the presence of HBT as mediator (L stage), an alkaline extraction (E stage) and a reductive treatment with NaBH 4 (R stage). The operating conditions for the L stage (laccase and HBT doses, reaction time and oxygen pressure) were optimised by using a sequential statistical plan to assess their influence on pulp properties after the E stage. Mathematical models accurately predicting brightness and kappa number in terms of the previous four variables were developed based on which the most influential factors were the laccase and HBT rates, and treatment time. By contrast, oxygen pressures of 0.2-0.6 MPa in the reactor had no effect on brightness or kappa number. The flax pulp obtained contained some oxidized cellulose that was partially degraded in the alkaline extraction step and reduced viscosity as a result. The viscosity loss associated with the presence of oxidized cellulose in the control and enzyme-treated pulp samples was efficiently recovered by using a reductive stage with sodium borohydride. Effluent was also analysed in order to assess the environmental impact of the process.

  7. OPTICAL PROPERTY ANALYSIS OF THERMALLY AND PHOTOLYTICALLY AGED EUCALYPTUS CAMALDULENSIS CHEMITHERMOMECHANICAL PULP (CTMP

    Directory of Open Access Journals (Sweden)

    Yao Chen,

    2012-02-01

    Full Text Available To investigate the optical properties of chemithermomechanical pulp (CTMP from Eucalyptus camaldulensis, one group of samples of CTMP was aged by heating, and another group was first subjected to bleaching with different bleaching agents, and then aging by exposure to sunlight. Chromophores were analyzed using diffuse reflectance UV-Vis spectra (DRUV, and the brightness and color parameters (L*, a*, b* were analyzed using colorimetry. Results showed that the color reactions of the pulp, upon heating, were enhanced in the presence of moisture. There was a linear relationship between the pulp initial moisture content (MC and the intensity of UV-Vis absorption. The contribution of different chromophores to pulp color was analyzed with the help of bleaching agents: hydrogen peroxide, sodium dithionite, and sodium borohydride. Sodium borohydride and hydrogen peroxide treatments resulted in a decrease in the absorption band at 280 nm along with the shoulder near 320 nm, which could be attributed to conjugated C=O and C=C systems. Similarly, sodium dithionite treatment also led to a decrease in absorption of the carbonyls and double bonds conjugated with aromatic double bonds. The chromaticity parameters of bleached pulp increased after exposure to sunlight. A correspondingly higher concentration of quinoid structures was found.

  8. PRODUCTION OF PRINTING AND WRITING PAPER GRADE PULP FROM ELEPHANT GRASS

    Directory of Open Access Journals (Sweden)

    Marcela Freitas Andrade

    2016-09-01

    Full Text Available The main goal of this study was to characterize chemically and morphologically elephant grass (Pennisetum purpureum, and evaluate the potential of its fibers for production of printing and writing paper grade pulp. The elephant grass was chemically and morphologically characterized and cooked by the soda process to two different degrees of delignification (kappa 17.5 and 10.6. The resulting pulps were fully bleached by the O-D*-(EP-D sequence and characterized for their beatability, drainability and physical-mechanical properties. The lignin content (20.2% was low, indicating that this grass should be easier to pulp. The morphological analyses of the elephant grass indicated a short fiber material, similar to hardwoods. The soda pulp from elephant grass cooked to kappa number 17.5 presented higher screened yield than 10.6 kappa pulp, with alkali demands of 15.0% and 20.0%, respectively. The total active chlorine required by the 17.5 and 10.6 kappa pulps, were 42.1 and 35.1 kg/odt pulp, respectively, to achieve an ISO brightness of approximately 90.0%. The bleached soda pulps cooked to 17.5 and 10.6 kappa number showed similar refinability and resistance to drainage, but the tensile and burst index were highest for the 17.5 kappa pulp at beating energy consumptions in the range of 0-6 Wh. It was concluded that both 10.6 and 17.5 kappa pulps from elephant grass are suitable for the production of printing and writing paper grade pulps, but the highest kappa 17.5 pulp is more economically attractive given its highest pulping yield, despite the significantly increased of chemical demand for bleaching A produção de papel para impressão e escrita Grau de celulose a partir de capim-elefante.

  9. Holdup time measurement by radioactive tracers in pulp production

    International Nuclear Information System (INIS)

    Roetzer, H.; Donhoffer, D.

    1988-12-01

    A batch of pulp was to be labelled before passing two bleaching towers of a pulp plant. Activated glass fibres were used as a tracer, which contained 24-Na with a half-life of 15 hours. It was shown in laboratory tests, that the glass fibres were suitable for transport studies of wood pulp. For use in the tests the fibres were activated and suspended in water. Due to the small diameter of the fibres (2-5 micrometers) this suspension shows physical properties very similar to the pulp. For detection six scintillation probes were mounted at different positions outside the bleaching tower. Radiation protection during the test was very easy due to the low total activity of the tracer material. Residence time distributions for both towers were measured. The successful tracer experiments show, that the method of labelling is suited for investigations of material transport in the pulp and paper industry. 3 figs., 11 refs., 2 tabs. (Author)

  10. A comprehensive program to develop correlations for physical properties of kraft black liquor. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Fricke, A.L.; Zaman, A.A.

    1998-05-01

    The overall objective of the program was to develop correlations to predict physical properties within requirements of engineering precision from a knowledge of pulping conditions and of kraft black liquor composition, if possible. These correlations were to include those relating thermodynamic properties to pulping conditions and liquor composition. The basic premise upon which the research was based is the premise that black liquor behaves as a polymer solution. This premise has proven to be true, and has been used successfully in developing data reduction methods and in interpreting results. A three phase effort involving pulping, analysis of liquor composition, and measurement of liquor properties was conducted.

  11. Steam slaking of lime - kinetics and technology. New energy effective lime slaking technology in kraft pulping; Aangslaeckning av kalk - kinetik och teknik. Ny energieffektiv teknik foer slaeckning av mesakalk i sulfatmassaindustrin

    Energy Technology Data Exchange (ETDEWEB)

    Lundqvist, Roland

    2008-06-15

    Lime stone is widely used in chemical recovery for regeneration of white liquor in kraft pulping. Slaked (hydrated) lime is used to convert (causticize) sodium carbonate into sodium hydroxide, whereby lime mud (calcium carbonate) precipitates from the solution. Lime mud is dried and reburned in a lime kiln, where burned lime (calcium oxide) is formed. The circle is closed when lime is slaked (hydrated) in green liquor in an exotherm reaction. Problems with traditional lime burning and slaking methods are that heat recovery is bad and heat is recovered at low temperatures. With the method described in this report there is potential to increase heat recovery in the causticizing plant, and to recover heat at higher temperatures. The forecasted method means that lime is slaked with water vapour, for example combined with an indirect heated lime mud drier and a lime kiln. This project is a follow-up to pilot tests performed in a specific machine equipment at year 2006. The target group is pulp and paper industry using the kraft process. The owner of this new project is Carnot AB and the project is performed inside the Vaermeforsk Program for Pulp and Paper Industry 2006-2008. Partners and advisers in project group have been KTH Energy Processes, CTH Energy and Environment, LTH Chemical Technology, SMA Mineral AB, and reference group from STORA Enso Skoghall, Sodra Cell, M-Real Husum and SCA Packaging Piteaa. The task in this stage has included market investigations and laboratory tests. Contacts have been made with suppliers, preliminary dimensioning of process equipment and budget offers are received. Economic calculations have been made out of the offers. The laboratory tests are done as an examination paper at KTH Energiprocesser on the reactivity of burned lime from kraft lime kiln when it is slaked with water vapour instead of green liquor. The vapour intended to be used is at atmospheric pressure or even down to 0,2 atm. Complementary addition to these laboratory

  12. Facilitating the enzymatic saccharification of pulped bamboo residues by degrading the remained xylan and lignin-carbohydrates complexes.

    Science.gov (United States)

    Huang, Caoxing; He, Juan; Li, Xin; Min, Douyong; Yong, Qiang

    2015-09-01

    Kraft pulping was performed on bamboo residues and its impact on the chemical compositions and the enzymatic digestibility of the samples were investigated. To improve the digestibility of sample by degrading the xylan and lignin-carbohydrates complexes (LCCs), xylanase and α-L-arabinofuranosidase (AF) were supplemented with cellulase. The results showed more carbohydrates were remained in the samples pulped with low effective alkali (EA) charge, compared to conventional kraft pulping. When 120 IU/g xylanase and 15 IU/g AF were supplemented with 20 FPU/g cellulase, the xylan degradation yield of the sample pulped with 12% EA charge increased from 68.20% to 88.35%, resulting in an increased enzymatic saccharification efficiency from 58.98% to 83.23%. The amount of LCCs in this sample decreased from 8.63/100C9 to 2.99/100C9 after saccharification with these enzymes. The results indicated that degrading the remained xylan and LCCs in the pulp could improve its enzymatic digestibility. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Comment on 'evaluation of dechlorination mechanisms during anaerobic fermentation of blached kraft mill effluent by W.J. Parker, E.R. Hall and G.J. Farquhar'

    Digital Repository Service at National Institute of Oceanography (India)

    Sarkar, A.

    Comment on "Evaluation of dechlorination mechanisms during anaerobic fermentation of bleached kraft mill effluent", is put forth. The data reproduced in Table 1 does not seem to be authentic as the method of preprationo of the chlorinated organic...

  14. Structural characterization of Kraft lignins from different spent cooking liquors by 1D and 2D Nuclear Magnetic Resonance spectroscopy

    International Nuclear Information System (INIS)

    Fernández-Costas, C.; Gouveia, S.; Sanromán, M.A.; Moldes, D.

    2014-01-01

    Three Kraft lignins isolated from black liquors of several paper pulp mills of the North of Spain and Portugal were structurally characterized by using monodimensional ( 1 H and 13 C) and bidimensional Nuclear Magnetic Resonance (NMR) spectrometry. From the latter, 13 C– 1 H heteronuclear single quantum correlation (HSQC) and heteronuclear multiple bond correlation (HMBC) were employed. Lignins from black liquors are usually burned for power generation. Nevertheless, they could become high value added products within a biorefinery context. In that case, a good understanding of their structure is a prior step to transform them. From all the NMR techniques studied, HSQC has risen as the most powerful tool in lignin characterization. Kraft cooking conditions and the type of wood seem to be the main factors that determine the differences observed in the lignins. All the samples have shown an important decrease in the number of β–O–4′ linkages, due to the Kraft process, and resinol has become the most resistant linkage to the process. Moreover, all samples seem to be mainly linked to a one polysaccharide: xylan. Several parameters like S/G ratio, portion of phenolic and aliphatic hydroxyls, amount of aromatic protons and other structural aspects were also estimated. - Highlights: • Lignins from three Kraft spent liquors were obtained by acid precipitation. • Structural characterization of the dissolved lignins was performed by NMR. • Wood source and pulping conditions determine the lignin characteristics. • Kraft process implies cleavage of β–O–4 linkages and survival of resinol linkages. • Comparison of the samples would aid decisions on its future revalorization

  15. Nova tecnologia de branqueamento de celulose adaptada ao fechamento do circuito de água A novel bleaching technology adapted to partial bleach plant closure

    Directory of Open Access Journals (Sweden)

    Marcelo Moreira Costa

    2006-02-01

    Full Text Available A Celulose Nipo-Brasileira é uma das maiores produtoras de celulose kraft branqueada de eucalipto no Brasil. Produz 860.000 tsa/ano em duas linhas, que são equipadas com digestores contínuos. Ambas as linhas fabricam polpa ECF (Elemental Chlorine Free com as seqüências Dhot(EOPD(EPD e D(EOPDP, respectivamente, na linha 1 e 2. A fábrica tem tratamento do efluente com lodo ativado com dois tanques de aeração com capacidade para 20.000 m³, equipados com aeradores superficiais seguidos por quatro clarificadores secundários (dois para cada reator. Nas últimas décadas, a fábrica tem otimizado e vem mudando seus processos, a fim de melhorar a preservação ambiental. Com o objetivo de reduzir o volume de efluente, DQO e carga de AOX, a seqüência Ahot(EOPD(PO proposta foi avaliada em testes laboratoriais, com reciclagem de filtrado parcial. Este artigo propôs a reciclagem de filtrado, que reduz o volume de efluente da fábrica em 9 m³/tsa (tonelada secada ao ar, isto é, mais ou menos 50% do total. O filtrado recuperado é parcialmente desviado para o ciclo de recuperação e para o estágio de deslignificação oxigênio. A reutilização do filtrado Ahot no ciclo de recuperação é para substituir os filtrados, atualmente usados para lavar lama de cal e "dregs". O impacto dos NPEs no ciclo de cálcio não foi significante. Essa estratégia permitiu uma recuperação de carga alcalina de 12 kg NaOH/tsa de polpa, que, do contrário, seria perdida. A branqueabilidade da polpa e a sua qualidade não foram afetadas significativamente. O efluente descartado, proveniente das etapas D(PO, mostrou-se com baixas cargas de cor, de DQO, de AOX e de uma boa biodegradabilidade (DBO5/DQO.Celulose Nipo-Brasileira is one of the largest eucalyptus bleached kraft pulp mills in Brazil. It produces 860,000 tpy in two lines that are equipped with continuous digesters. Line 1 and line 2 produces ECF (Elemental Chlorine Free pulp with the sequences: Dhot

  16. A survey of present levels of radiocesium in Swedish pulp mill liquors and the implications for wood radiocesium transfer factors

    International Nuclear Information System (INIS)

    Ravila, A.; Holm, E.

    1998-01-01

    Assessments of the impact from radioactive fallout on the pulp industry and the accumulation processes for radionuclides in such industries, using wood and water as primary raw materials, have been conducted in previous studies. Hitherto, there is a general lack of data on present levels of radioactivity in pulp mill liquors apart from the few mills studied by [NILSSON (1992)] [RAVILA AND HOLM (1992)] [MANJON ET AL. (1996) and [KROSSHAVN ET AL. (1997)]. A survey was therefore initiated to describe and compare the present activity levels in pulp mill liquors from various mill locations in Sweden. The 137 Cs activity in pulp mill liquors were compared with the mill location and the deposition pattern of the Chernobyl fallout and nuclear weapons fallout. The large input of wood (approx. 2500 m 3 day -1 ) to an average Nordic Kraft mill and the relatively long-term retention time for radiocesium in the Kraft mill recovery cycle enables representative sampling of substances directly related to the activity concentration in wood

  17. Influence of the chemical composition on the combustion properties of kraft black liquor; Mustalipeaen koostumuksen vaikutus lipeaen poltto-ominaisuuksiin

    Energy Technology Data Exchange (ETDEWEB)

    Alen, R; Siistonen, H; Malkavaara, P [Jyvaeskylae Univ. (Finland). Inst. of Chemistry

    1997-10-01

    The aim of this work is to study the combustion properties of kraft black liquors from modified cooking. Both the industrial and laboratory-made black liquors are included. In addition, changes in the combustion properties of the spent liquors obtained by mixing prior to combustion different chlorine-free bleach liquors with black liquor are studied. (orig.)

  18. Biopulping of sugarcane bagasse and decolorization of kraft liquor by the laccase produced by Klebsiella aerogenes NCIM 2098

    Directory of Open Access Journals (Sweden)

    Jha H.

    2013-12-01

    Full Text Available Aims: Laccase, a copper-containing enzyme, oxidizes variety of aromatic compounds. Since laccase is essential for lignin degradation, it can be used for lignin removal in the pulp and paper industry (biopulping. Laccase is also employed as a dechlorinating agent (biobleaching, along with the removal of phenolic and other aromatic pollutants. In the present investigation it was aimed to employ the laccase produced by the bacterium Klebsiella aerogenes along with the bacterium itself in biopulping of sugarcane bagasse and biobleaching of kraft liquor effluent. Methodology and results: A laccase was isolated from the bacterium K. aerogenes, purified to homogeneity and characterized. The enzyme was purified by conventional techniques following salt precipitation, ion exchange chromatography, and affinity chromatography on Con A sepharose. The purified laccase was found to be monomeric glycoprotein with a Mr of 64 kDa when measured by Sephadex G-200 gel chromatography and SDS-PAGE. The Vmax and Km of laccase towards the substrate guaiacol was determined. The optimum pH of the laccase was found to be 5.0. biopulping and biobleaching activities were determined by TAPPI standard methods. Treatment of sugarcane baggase by K. aerogenes also significantly reduced lignin content of the bagasse. Conclusion, significance and impact of study: The bacterium K. aerogenes and a laccase produced by it were used separately for biopulping of sugarcane bagasse and biobleaching of kraft liquor effluent. Treatment with both brought significant reduction in lignin content and kappa number of the pulp. The handsheets prepared from the treated pulp showed improved brightness without affecting the strength properties of paper. The bacterium and the laccase efficiently decolorized the kraft liquor proving to have biobleaching potential.

  19. Mill Integration-Pulping, Stream Reforming and Direct Causticization for Black Liquor Recovery

    Energy Technology Data Exchange (ETDEWEB)

    Adriaan van Heiningen

    2007-06-30

    MTCI/StoneChem developed a steam reforming, fluidized bed gasification technology for biomass. DOE supported the demonstration of this technology for gasification of spent wood pulping liquor (or 'black liquor') at Georgia-Pacific's Big Island, Virginia mill. The present pre-commercial R&D project addressed the opportunities as well as identified negative aspects when the MTCI/StoneChem gasification technology is integrated in a pulp mill production facility. The opportunities arise because black liquor gasification produces sulfur (as H{sub 2}S) and sodium (as Na{sub 2}CO{sub 3}) in separate streams which may be used beneficially for improved pulp yield and properties. The negative aspect of kraft black liquor gasification is that the amount of Na{sub 2}CO{sub 3} which must be converted to NaOH (the so called causticizing requirement) is increased. This arises because sulfur is released as Na{sub 2}S during conventional kraft black liquor recovery, while during gasification the sodium associated Na{sub 2}S is partly or fully converted to Na{sub 2}CO{sub 3}. The causticizing requirement can be eliminated by including a TiO{sub 2} based cyclic process called direct causticization. In this process black liquor is gasified in the presence of (low sodium content) titanates which convert Na{sub 2}CO{sub 3} to (high sodium content) titanates. NaOH is formed when contacting the latter titanates with water, thereby eliminating the causticizing requirement entirely. The leached and low sodium titanates are returned to the gasification process. The project team comprised the University of Maine (UM), North Carolina State University (NCSU) and MTCI/ThermoChem. NCSU and MTCI are subcontractors to UM. The principal organization for the contract is UM. NCSU investigated the techno-economics of using advanced pulping techniques which fully utilize the unique cooking liquors produced by steam reforming of black liquor (Task 1). UM studied the kinetics and

  20. Durability of pulp fiber-cement composites

    Science.gov (United States)

    Mohr, Benjamin J.

    Wood pulp fibers are a unique reinforcing material as they are non-hazardous, renewable, and readily available at relatively low cost compared to other commercially available fibers. Today, pulp fiber-cement composites can be found in products such as extruded non-pressure pipes and non-structural building materials, mainly thin-sheet products. Although natural fibers have been used historically to reinforce various building materials, little scientific effort has been devoted to the examination of natural fibers to reinforce engineering materials until recently. The need for this type of fundamental research has been emphasized by widespread awareness of moisture-related failures of some engineered materials; these failures have led to the filing of national- and state-level class action lawsuits against several manufacturers. Thus, if pulp fiber-cement composites are to be used for exterior structural applications, the effects of cyclical wet/dry (rain/heat) exposure on performance must be known. Pulp fiber-cement composites have been tested in flexure to examine the progression of strength and toughness degradation. Based on scanning electron microscopy (SEM), environmental scanning electron microscopy (ESEM), energy dispersive spectroscopy (EDS), a three-part model describing the mechanisms of progressive degradation has been proposed: (1) initial fiber-cement/fiber interlayer debonding, (2) reprecipitation of crystalline and amorphous ettringite within the void space at the former fiber-cement interface, and (3) fiber embrittlement due to reprecipitation of calcium hydroxide filling the spaces within the fiber cell wall structure. Finally, as a means to mitigate kraft pulp fiber-cement composite degradation, the effects of partial portland cement replacement with various supplementary cementitious materials (SCMs) has been investigated for their effect on mitigating kraft pulp fiber-cement composite mechanical property degradation (i.e., strength and toughness

  1. Recovering/concentrating of hemicellulosic sugars and acetic acid by nanofiltration and reverse osmosis from prehydrolysis liquor of kraft based hardwood dissolving pulp process.

    Science.gov (United States)

    Ahsan, Laboni; Jahan, M Sarwar; Ni, Yonghao

    2014-03-01

    This work investigated the feasibility of recovering and concentrating sugars and acetic acid (HAc) from prehydrolysis liquor (PHL) of the kraft-based dissolving pulp process prior to fermentation of hemicellulosic sugars, by the combination of activated carbon adsorption, nanofiltration (NF) and reverse osmosis (RO) processes. To reduce the fouling PHL was subjected to adsorption on activated carbon, then the treated PHL (TPHL) passed through a nanofiltration (NF DK) membrane to retain the sugars, and the permeate of acetic acid rich solution was passed through a reverse osmosis membrane (RO SG). It was found that for NF process sugars were concentrated from 48 to 227g/L at a volume reduction factor (VRF) of 5 while 80 to 90% of acetic acid was permeated. For the reverse osmosis process, 68% of acetic acid retention was achieved at pH 4.3 and 500 psi pressure and the HAc concentration increased from 10 to 50g/L. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  2. Biobleaching of wheat straw-rich soda pulp with alkalophilic laccase from gamma-proteobacterium JB: optimization of process parameters using response surface methodology.

    Science.gov (United States)

    Singh, Gursharan; Ahuja, Naveen; Batish, Mona; Capalash, Neena; Sharma, Prince

    2008-11-01

    An alkalophilic laccase from gamma-proteobacterium JB was applied to wheat straw-rich soda pulp to check its bleaching potential by using response surface methodology based on central composite design. The design was employed by selecting laccase units, ABTS (2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)) concentration and pH as model factors. The results of second order factorial design experiments showed that all three independent variables had significant effect on brightness and kappa number of laccase-treated pulp. Optimum conditions for biobleaching of pulp with laccase preparation (specific activity, 65 nkat mg(-1) protein) were 20 nkat g(-1) of pulp, 2mM ABTS and pH 8.0 which enhanced brightness by 5.89% and reduced kappa number by 21.1% within 4h of incubation at 55 degrees C, without further alkaline extraction of pulp. Tear index (8%) and burst index (18%) also improved for laccase-treated pulp as compared to control raw pulp. Treatment of chemically (CEH1H2) bleached pulp with laccase showed significant effect on release of chromophores, hydrophobic and reducing compounds. Laccase-prebleaching of raw pulp reduced the use of hypochlorite by 10% to achieve brightness of resultant hand sheets similar to the fully chemically bleached pulp.

  3. 40 CFR 430.03 - Best management practices (BMPs) for spent pulping liquor, soap, and turpentine management, spill...

    Science.gov (United States)

    2010-07-01

    ... gases from the cooking of softwoods by the kraft pulping process. Sometimes referred to as sulfate... professional judgment. [63 FR 18635, Apr. 15, 1998, as amended at 65 FR 46108, July 27, 2000] ...

  4. Possible mechanism for anthraquinone species diffusion in alkaline pulping

    Science.gov (United States)

    X.-S. Chai; J. Samp; Q.X. Hou; S.-H Yoon; J.Y. Zhu

    2007-01-01

    An analysis of the effectiveness of anthraquinone (AQ) in kraft-AQ pulping in terms of its mechanism of transport has been conducted. Our previous work showed that caustic solutions of wood lignin can decrease the membrane exclusion for anthraquinones, i.e., the presence of wood lignin enhances the ability of AQ to pass through a membrane when a reducing agent is...

  5. Efficacy and cytotoxicity of a bleaching gel after short application times on dental enamel.

    Science.gov (United States)

    Soares, Diana Gabriela; Ribeiro, Ana Paula Dias; da Silveira Vargas, Fernanda; Hebling, Josimeri; de Souza Costa, Carlos Alberto

    2013-11-01

    This study aimed to evaluate and correlate the efficacy and cytotoxicity of a 35 % hydrogen peroxide (HP) bleaching gel after different application times on dental enamel. Enamel/dentin disks in artificial pulp chambers were placed in wells containing culture medium. The following groups were formed: G1, control (no bleaching); G2 and G3, three or one 15-min bleaching applications, respectively; and G4 and G5, three or one 5-min bleaching applications, respectively. Extracts (culture medium with bleaching gel components) were applied for 60 min on cultured odontoblast-like MDPC-23 cells. Cell metabolism (methyl tetrazolium assay) (Kruskal-Wallis/Mann-Whitney; α = 5 %) and cell morphology (scanning electron microscopy) were analyzed immediately after the bleaching procedures and the trans-enamel and trans-dentinal HP diffusion quantified (one-way analysis of variance/Tukey's test; α = 5 %). The alkaline phosphatase (ALP) activity was evaluated 24 h after the contact time of the extracts with the cells (Kruskal-Wallis/Mann-Whitney; α = 5 %). Tooth color was analyzed before and 24 h after bleaching using a spectrophotometer according to the Commission Internationale de l'Eclairage L*a*b* system (Kruskal-Wallis/Mann-Whitney; α = 0.05). Significant difference (p 0.05). The lowest amount of HP diffusion was observed in G5 (p 0.05). HP diffusion through dental tissues and its cytotoxic effects were proportional to the contact time of the bleaching gel with enamel. However, shorter bleaching times reduced bleaching efficacy. Shortening the in-office tooth bleaching time could be an alternative to minimize the cytotoxic effects of this clinical procedure to pulp tissue. However, the reduced time of bleaching agent application on enamel may not provide adequate esthetic outcome.

  6. The corrosion of titanium and some other construction materials during hydrogen peroxide bleaching according to the field measurements

    International Nuclear Information System (INIS)

    Hyoekyvirta, O.; Pohjanne, P.; Heinaevaara, A.; Hirvonen, J.; Lewenstam, A.

    1999-01-01

    In a Finnish pulp mill, the field measurements of different materials were performed in different stages of peroxide bleaching: P 1 and P 2 . The field measurements were performed with three different sensors. The sensors were designed in co-operation with Valmet Automation Kajaani Oy. Each sensor measured the corrosion potential, the redox potential and the weight losses of three different materials. Simultaneously, the data of the most important parameters of bleaching, i.e. temperature, pH, peroxide flow rate and concentration, mass flow, consistency, residuals, flow rate and concentration of alkaline, were collected in the data logger by a dedicated program. The results proved that the corrosion of different materials (stainless steel S31654, nickel-based alloy N10276 and titanium Gr. 5) could be estimated with field experiments. The uniform corrosion of titanium occurred in a certain bleaching situation. The field measurements gave a good estimation of whether the material dissolved during process operation or process disorders. Our results clearly show that the mixing of the chemicals can be reliably estimated, and thus advantageous for a pulp mill. The materials studied withstood the bleaching significantly better if the chemicals were mixed directly with a pulp. Usually the chemicals are mixed with alkaline and then added to the pulp. The field measurements could also be applied in ozone and in the peracetic acid bleaching stage. The sensors can be utilized as tools during process monitoring or diagnostics. With the aid of monitoring it is possible to clarify how the different process operation models affect the corrosion of materials. (author)

  7. The corrosion of titanium and some other construction materials during hydrogen peroxide bleaching according to the field measurements

    Energy Technology Data Exchange (ETDEWEB)

    Hyoekyvirta, O.; Pohjanne, P.; Heinaevaara, A. [Oy METSA-BOTNIA Ab, Kaskinen' s mill, 64260 Kaskinen (Finland); Hirvonen, J. [VTT Automation, Industrial Automation, P.O. Box 1301, FIN-02044 (Finland); Lewenstam, A. [Center for Process Analytical Chemistry and Sensor Technology ' ProSens' Abo Akademi University, 20500 Abo (Finland)

    1999-07-01

    In a Finnish pulp mill, the field measurements of different materials were performed in different stages of peroxide bleaching: P{sub 1} and P{sub 2}. The field measurements were performed with three different sensors. The sensors were designed in co-operation with Valmet Automation Kajaani Oy. Each sensor measured the corrosion potential, the redox potential and the weight losses of three different materials. Simultaneously, the data of the most important parameters of bleaching, i.e. temperature, pH, peroxide flow rate and concentration, mass flow, consistency, residuals, flow rate and concentration of alkaline, were collected in the data logger by a dedicated program. The results proved that the corrosion of different materials (stainless steel S31654, nickel-based alloy N10276 and titanium Gr. 5) could be estimated with field experiments. The uniform corrosion of titanium occurred in a certain bleaching situation. The field measurements gave a good estimation of whether the material dissolved during process operation or process disorders. Our results clearly show that the mixing of the chemicals can be reliably estimated, and thus advantageous for a pulp mill. The materials studied withstood the bleaching significantly better if the chemicals were mixed directly with a pulp. Usually the chemicals are mixed with alkaline and then added to the pulp. The field measurements could also be applied in ozone and in the peracetic acid bleaching stage. The sensors can be utilized as tools during process monitoring or diagnostics. With the aid of monitoring it is possible to clarify how the different process operation models affect the corrosion of materials. (author)

  8. The use of biomass energy in the pulp and paper industry and the prospects for black liquor gasification combined cycle generation

    International Nuclear Information System (INIS)

    Nilsson, L.J.

    1995-01-01

    The world production of paper and paperboard products, which increased 3.3% per year since 1980, reached 243 million tonnes in 1991 and is expected to continue to grow by about 2.5% per year over the next decade. Consumption levels in 1990 ranged from 2.8 kg per capita in India to 313 kg per capita in the United States. The biggest producers of pulp are the United States, Canada and the Scandinavian countries, but much of the expansion of pulp production capacity is taking place in countries such as Brazil, Chile and Indonesia. The pulp and paper industry has always relied on biomass as a fuel source to meet process energy demands. Kraft pulping is the most common process accounting for about two thirds of world wood pulp production. Energy recovered from burning black liquor, a lignin-rich by-product, in a chemicals recovery boiler typically provides most of the on-site demand for heat and electricity in a modem kraft pulp mill. Another important fuel source is bark and wood waste generated at the mill. Aging recovery boilers in industrialized countries and increasing electricity/heat demand ratios are stimulating interest in alternative co-generation technologies. Most of the interest in new biomass and black liquor co-generation technologies focuses on those that would utilize gas turbines rather than steam turbines. Gas turbines are generally characterized by higher electricity/heat ratios than steam turbines, as well as lower unit capital costs. With the black liquor and biomass gasification technologies that are now being developed and demonstrated, the energy needs of an energy-efficient kraft pulp mill could be met and 40-50 MW of baseload power would be available for export. Using, in addition, currently unused logging residues for fuel would increase that potential. The pulp and paper industry is likely to be an important early market for advanced biomass-based cogeneration technology owing to its access to biomass fuels and the potential for co

  9. The use of biomass energy in the pulp and paper industry and the prospects for black liquor gasification combined cycle generation

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, L J [Department of Environmental and Energy Systems Studies, Lund University, Lund (Sweden)

    1995-12-01

    The world production of paper and paperboard products, which increased 3.3% per year since 1980, reached 243 million tonnes in 1991 and is expected to continue to grow by about 2.5% per year over the next decade. Consumption levels in 1990 ranged from 2.8 kg per capita in India to 313 kg per capita in the United States. The biggest producers of pulp are the United States, Canada and the Scandinavian countries, but much of the expansion of pulp production capacity is taking place in countries such as Brazil, Chile and Indonesia. The pulp and paper industry has always relied on biomass as a fuel source to meet process energy demands. Kraft pulping is the most common process accounting for about two thirds of world wood pulp production. Energy recovered from burning black liquor, a lignin-rich by-product, in a chemicals recovery boiler typically provides most of the on-site demand for heat and electricity in a modem kraft pulp mill. Another important fuel source is bark and wood waste generated at the mill. Aging recovery boilers in industrialized countries and increasing electricity/heat demand ratios are stimulating interest in alternative co-generation technologies. Most of the interest in new biomass and black liquor co-generation technologies focuses on those that would utilize gas turbines rather than steam turbines. Gas turbines are generally characterized by higher electricity/heat ratios than steam turbines, as well as lower unit capital costs. With the black liquor and biomass gasification technologies that are now being developed and demonstrated, the energy needs of an energy-efficient kraft pulp mill could be met and 40-50 MW of baseload power would be available for export. Using, in addition, currently unused logging residues for fuel would increase that potential. The pulp and paper industry is likely to be an important early market for advanced biomass-based cogeneration technology owing to its access to biomass fuels and the potential for co

  10. Recycling cellulase towards industrial application of enzyme treatment on hardwood kraft-based dissolving pulp.

    Science.gov (United States)

    Wang, Qiang; Liu, Shanshan; Yang, Guihua; Chen, Jiachuan; Ji, Xingxiang; Ni, Yonghao

    2016-07-01

    Cost-effectiveness is vital for enzymatic treatment of dissolving pulp towards industrial application. The strategy of cellulase recycling with fresh cellulase addition was demonstrated in this work to activate the dissolving pulp, i.e. decreasing viscosity and increasing Fock reactivity. Results showed that 48.8-35.1% of cellulase activity can be recovered from the filtered liquor in five recycle rounds, which can be reused for enzymatic treatment of dissolving pulp. As a result, the recycling cellulase with addition fresh cellulase of 1mg/g led to the pulp of viscosity 470mL/g and Fock reactivity 80%, which is comparable with cellulase charge of 2mg/g. Other pulp properties such as alpha-cellulose, alkaline solubility and molecular weight distribution were also determined. Additionally, a zero-release of recycling cellulase treatment was proposed to integrate into the dissolving pulp production process. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. A clinical assessment of the effects of 10% carbamide peroxide gel on human pulp tissue.

    Science.gov (United States)

    Anderson, D G; Chiego, D J; Glickman, G N; McCauley, L K

    1999-04-01

    Bleaching vital teeth with 10% carbamide peroxide gel is a routine procedure in which there has been no evidence of associated permanent pulpal damage. Synthesis of the enzyme heme oxygenase-1 (HO-1) is increased after exposure of eukaryotic cells to conditions of oxidative stress (including H2O2) as a defense against the damaging effects of free radicals. Dental pulps were evaluated for HO-1 (aka Heat Shock Protein 32) presence in teeth treated with 10% carbamide peroxide. Seventeen intact first premolars scheduled for orthodontic extraction were bleached for 4 h immediately preceding extraction. Fourteen additional premolars from the same individuals were not bleached. All 31 teeth were extracted, fixed, demineralized, frozen, sectioned, and immunostained with anti-HO-1 antibody using a standard ABC protocol. There was no significant difference in the presence of HO-1 between total bleached versus total unbleached teeth using the Fisher's Exact Test (p pulp proper may have the potential to respond to oxidative stress by increasing the synthesis of HO-1 (HSP32). This could represent a component of an initial defensive response by specific cells in strategic locations in the pulp that precedes classical inflammatory pathways.

  12. A xylanase-aided enzymatic pretreatment facilitates cellulose nanofibrillation.

    Science.gov (United States)

    Long, Lingfeng; Tian, Dong; Hu, Jinguang; Wang, Fei; Saddler, Jack

    2017-11-01

    Although biological pretreatment of cellulosic fiber based on endoglucanases has shown some promise to facilitate cellulose nanofibrillation, its efficacy is still limited. In this study, a xylanase-aided endoglucanase pretreatment was assessed on the bleached hardwood and softwood Kraft pulps to facilitate the downstream cellulose nanofibrillation. Four commercial xylanase preparations were compared and the changes of major fiber physicochemical characteristics such as cellulose/hemicellulose content, gross fiber properties, fiber morphologies, cellulose accessibility/degree of polymerization (DP)/crystallinity were systematically evaluated before and after enzymatic pretreatment. It showed that the synergistic cooperation between endoglucanase and certain xylanase (Biobrite) could efficiently "open up" the hardwood Kraft pulp with limited carbohydrates degradation (cellulose nanofibrillation during mild sonication process (90Wh) with more uniform disintegrated nanofibril products (50-150nm, as assessed by scanning electron microscopy and UV-vis spectroscopy). Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Composite tube cracking in kraft recovery boilers: A state-of-the-art review

    Energy Technology Data Exchange (ETDEWEB)

    Singbeil, D.L.; Prescott, R. [Pulp and Paper Research Inst. of Canada, Vancouver, British Columbia (Canada); Keiser, J.R.; Swindeman, R.W. [Oak Ridge National Lab., TN (United States)

    1997-07-01

    Beginning in the mid-1960s, increasing energy costs in Finland and Sweden made energy recovery more critical to the cost-effective operation of a kraft pulp mill. Boiler designers responded to this need by raising the steam operating pressure, but almost immediately the wall tubes in these new boilers began to corrode rapidly. Test panels installed in the walls of the most severely corroding boiler identified austenitic stainless steel as sufficiently resistant to the new corrosive conditions, and discussions with Sandvik AB, a Swedish tube manufacturer, led to the suggestion that coextruded tubes be used for water wall service in kraft recovery boilers. Replacement of carbon steel by coextruded tubes has solved most of the corrosion problems experienced by carbon steel wall tubes, however, these tubes have not been problem-free. Beginning in early 1995, a multidisciplinary research program funded by the US Department of Energy was established to investigate the cause of cracking in coextruded tubes and to develop improved materials for use in water walls and floors of kraft recovery boilers. One portion of that program, a state-of-the-art review of public- and private-domain documents related to coextruded tube cracking in kraft recovery boilers is reported here. Sources of information that were consulted for this review include the following: tube manufacturers, boiler manufacturers, public-domain literature, companies operating kraft recovery boilers, consultants and failure analysis laboratories, and failure analyses conducted specifically for this project. Much of the information contained in this report involves cracking problems experienced in recovery boiler floors and those aspects of spout and air-port-opening cracking not readily attributable to thermal fatigue. 61 refs.

  14. Application of a novel alkali-tolerant thermostable DyP-type peroxidase from Saccharomonospora viridis DSM 43017 in biobleaching of eucalyptus kraft pulp.

    Directory of Open Access Journals (Sweden)

    Wangning Yu

    Full Text Available Saccharomonospora viridis is a thermophilic actinomycete that may have biotechnological applications because of its dye decolorizing activity, though the enzymatic oxidative system responsible for this activity remains elusive. Bioinformatic analysis revealed a DyP-type peroxidase gene in the genome of S. viridis DSM 43017 with sequence similarity to peroxidase from dye-decolorizing microbes. This gene, svidyp, consists of 1,215 bp encoding a polypeptide of 404 amino acids. The gene encoding SviDyP was cloned, heterologously expressed in Escherichia coli, and then purified. The recombinant protein could efficiently decolorize several triarylmethane dyes, anthraquinonic and azo dyes under neutral to alkaline conditions. The optimum pH and temperature for SviDyP was pH 7.0 and 70°C, respectively. Compared with other DyP-type peroxidases, SviDyP was more active at high temperatures, retaining>63% of its maximum activity at 50-80°C. It also showed broad pH adaptability (>35% activity at pH 4.0-9.0 and alkali-tolerance (>80% activity after incubation at pH 5-10 for 1 h at 37°C, and was highly thermostable (>60% activity after incubation at 70°C for 2 h at pH 7.0. SviDyP had an accelerated action during the biobleaching of eucalyptus kraft pulp, resulting in a 21.8% reduction in kappa number and an increase of 2.98% (ISO in brightness. These favorable properties make SviDyP peroxidase a promising enzyme for use in the pulp and paper industries.

  15. Nanofibrillated cellulose as paper additive in Eucalyptus pulps

    Directory of Open Access Journals (Sweden)

    Israel González

    2012-11-01

    Full Text Available In this work, the physical and mechanical properties of bleached Eucalyptus pulp reinforced with nanofibrillated cellulose (NFC are compared with those of traditional beaten pulp used in the making of writing/printing and offset printing papers. For this purpose, three different types of hardwood slurries were prepared: beaten pulps, unbeaten pulps reinforced with NFC, and slightly beaten pulps also reinforced with NFC. Physical and mechanical tests were performed on handsheets from these different slurries. The results showed that adding NFC to unbeaten pulps results in physical and mechanical properties similar to those in pulps used for printing/writing papers. Nevertheless, the best results were obtained in slurries previously beaten at slight conditions and subsequently reinforced with NFC. These results demonstrate that the addition of NFC allows a reduction in beating intensity without decreasing the desired mechanical properties for this specific purpose.

  16. Evaluation of opportunities for heat integration of biomass-based Fischer–Tropsch crude production at Scandinavian kraft pulp and paper mill sites

    International Nuclear Information System (INIS)

    Ljungstedt, Hanna; Pettersson, Karin; Harvey, Simon

    2013-01-01

    This study investigates heat integrated production of FT (Fischer–Tropsch) crude, where excess heat from the FT crude plant is delivered to a typical Scandinavian pulp and paper mill that produces fine paper. The sizes of FT crude plants are quantified, when the amount of excess heat from the FT plant exactly matches the heating demand otherwise satisfied by the bark boiler at the mill, considering a number of development pathways at the mill, including various degrees of steam savings and biorefinery options, such as lignin extraction. Performance of integrated production is compared with that of an FT stand-alone plant on the basis of wood fuel-to-FT crude efficiency, GHG (greenhouse gas) emissions balances and FT crude production cost. The results show that there exists a heat integration opportunity for an FT crude plant ranging from 0 up to 350 MW (LHV) of wood fuel depending on the development pathway for the mill. The results indicate higher overall efficiency and a generally lower production cost for the heat integrated, co-located production. Heat integrated production has a larger potential to contribute to GHG emission mitigation, assuming a future generation of grid electricity emitting equal to or less than an NGCC (natural gas combined cycle) power plant. - Highlights: • We investigate opportunities for heat integrated FT crude production at a mill. • Typical kraft pulp and paper mills have a potential for heat integrated production. • We compare the heat integrated production with stand-alone FT crude production. • Higher efficiency and lower production cost for heat integrated production. • Reduction of GHG emissions is strongly dependent on grid electricity emissions

  17. Preparation of lumen-loaded kenaf pulp with magnetite (Fe3O4)

    International Nuclear Information System (INIS)

    Zakaria, S.; Ong, B.H.; Ahmad, S.H.; Abdullah, M.; Yamauchi, T.

    2005-01-01

    Magnetic pulps were prepared from unbleached kenaf (hibiscus cannabinus L.) kraft pulps. Fe 3 O 4 or magnetite powder was used to load into the pulp's lumen and pit. Aluminum sulphate [Al 2 (SO 4 ) 3 ] (alum) and polyethylenimine (PEI), both mainly function as retention aid were used throughout the experiment and found to be beneficial in the preparation of this magnetic pulps. The ash content method was used to determine the amount of magnetite retained in the lumen and pit. The utilization of PEI up to 2% per pulp fibres was found to be the best result on lumen loading. The deposition of magnetite powder in lumen and pit is found decrease as the addition of PEI used is more than 2% per pulp fibres. Scanning electron microscope (SEM) clearly shows the distribution of magnetite deposited in the lumen. Tensile index and folding endurance of the loaded fibre decreased slightly as the percentage of loading pigment increased

  18. Irrigation model of bleached Kraft mill wastewater through volcanic soil as a pollutants attenuation process.

    Science.gov (United States)

    Navia, R; Inostroza, X; Diez, M C; Lorber, K E

    2006-05-01

    An irrigation process through volcanic soil columns was evaluated for bleached Kraft mill effluent pollutants retention. The system was designed to remove color and phenolic compounds and a simple kinetic model for determining the global mass transfer coefficient and the adsorption rate constant was used. The results clearly indicate that the global mass transfer coefficient values (K(c)a) and the adsorption rate constants are higher for the irrigation processes onto acidified soil. This means that the pretreatment of washing the volcanic soil with an acid solution has a positive effect on the adsorption rate for both pollutant groups. The enhanced adsorption capacity is partially explained by the activation of the metal oxides present in the soil matrix during the acid washing process. Increasing the flow rate from 1.5 to 2.5 ml/min yielded higher (K(c)a) values and adsorption rate constants for both pollutant groups. For instance, regarding color adsorption onto acidified soil, there is an increment of 43% in the (K(c)a) value for the experiment with a flow rate of 2.5 ml/min. Increasing the porosity of the column from 0.55 to 0.59, yielded a decrease in the (K(c)a) values for color and phenolic compounds adsorption processes. Onto natural soil for example, these decreases reached 21% and 24%, respectively. Therefore, the (K(c)a) value is dependent on both the liquid-phase velocity (external resistance) and the soil fraction in the column (internal resistance); making forced convection and diffusion to be the main transport mechanisms involved in the adsorption process. Analyzing the adsorption rate constants (K(c)a)/m, phenolic compounds and color adsorption rates onto acidified soil of 2.25 x 10(-6) and 2.62 x 10(-6) l/mg min were achieved for experiment 1. These adsorption rates are comparable with other adsorption systems and adsorbent materials.

  19. Combustion properties of kraft black liquors; Ligniinifraktion vaikutus mustalipeaen poltto-ominaisuuksiin

    Energy Technology Data Exchange (ETDEWEB)

    Alen, R.; Rantanen, K.; Ekman, J.; Malkavaara, P. [Jyvaeskylae Univ. (Finland)

    1996-12-01

    The aim of this investigation was to find relationships between the structure of the dissolved lignin and the combustion properties (pyrolysis time, char burning time, and swelling) of softwood and hardwood kraft black liquors. In this conjunction, pine and birch chips, as well as their two mixtures (the mass ratios of pine chips to birch chips were 80:20 and 60:40), were delignified by conventional kraft pulping. In each cook series, a liquor sample was withdrawn at certain time intervals to obtain liquor samples with different chemical composition. The black liquors obtained were analyzed with respect to the content of lignin and `lignin monomers`, but also the molecular-mass distribution and the mass average molecular mass of lignin were made. In addition, the dissolved lignin was characterized by NMR spectroscopy and elemental analysis. Further data on the chemical structures of lignin in black liquors were obtained by identifying various degradation products formed from this material during oxidative (CuO oxidation) and pyrolytic treatments. Several correlations between the `structural parameters` of the dissolved lignin and the combustion properties of black liquor were found. These correlations were significant especially in the case of pine cook. The results revealed many findings which are, together with the earlier data, useful for a better understanding of the thermochemical behavior of different kraft black liquors during combustion in a recovery furnace. (author)

  20. PULP OBTAINING METHOD FOR PACKAGE PRODUCTION

    Directory of Open Access Journals (Sweden)

    V. V. Kuzmich

    2015-01-01

    Full Text Available The paper presents a new method for obtaining pulp which is used for production of cardboard, paper and package while using carbon dioxide and hydrazine hydrate and neutral-sulfite  shive cooking. Output increase of  the desired product can be explained by reduction in destruction of plant raw material carbohydrates during its cooking process. Quality improvement of the desired product (improvement in bleaching and output is attributed to the fact that usage of carbon dioxide and hydrazine contributes to provision of polysaccharide chain resistance to destruction due to the presence of  end links having structure of metasaccharinic and aldonic acids.The author has developed a new method for pulp obtaining on the basis of the executed investigations  and literature data.  СО2 and hydrazine hydrate have been used for obtaining pulp. Method invention concerns pulp obtaining and it can be used for paper and cardboard package manufacturing in pulp and paper industry.The method is to be carried in the following way: pulp-containing plant raw material is loaded into an autoclave and then aqua solution of sodium monosulfite containing hydrazine hydrate that constitutes 4–5 % of absolute dry pulp-containing raw material mass with liquid module 1:6–1:8 is supplied into the autoclave. The autoclave is closed for operation under pressure and the solution is carbonated under pressure which constitutes 5–8 % of absolute dry plant raw material (shover. Temperature is subsequently raised up to 180 °С in the space of 2 hours and cooking is carried out in the course of 4 hours. Usage of  the proposed method for shover cooking makes it possible to reduce monosulfite cooking process and improve qualitative characteristics and output of the desired product.  In addition to above mentioned fact there is a possibility to improve bleaching and final product output. 

  1. BRANQUEAMENTO COM OZÔNIO EM PH NEUTRO ¿ UM NOVO CONCEITO

    Directory of Open Access Journals (Sweden)

    Fernando De Carvalho

    2006-01-01

    Full Text Available The effect of medium consistency ozone stage pH was evaluated for brown and oxygen delignified eucalyptus kraft pulp samples obtained from VCP - Luiz Antônio pulp mill. These samples were used as such or previously treated with the hot acid stage (A. The main objective of this study was to determine the viability of increasing the ozone stage pH aiming at decreasing bleaching variable costs. The ozone stage was studied in the pH range of 2.5-9.0, taking into account some important variables which affect ozone bleaching: (1 pulp kappa number entering the ozone stage, (2 reactivity of ozone towards lignin versus hexenuronic acids (HexA´s, (3 pulp treatments prior to ozone stage (acid hydrolysis, and (4 pulp treatments after the ozone stage (extraction or a chlorine dioxide stage. Therefore, the impact of ozone stage pH was investigated in bleaching process such as Z/DEop vs AZ/DEop, Z/DEopD vs AZ/DEopD, Z/E vs AZ/E. The results were interpreted based on ozone stage efficiency and selectivity, and overall bleaching performance measured by the total bleaching chemical consumption required to achieve full brightness, pulp quality and environmental impact. It was concluded that the increase of ozone stage pH from 2.5 to 7.0 has a slightly negative impact on the efficiency and selectivity, measured after Z/DEop sequence, but this effect is not expressive in the end of Z/DEopD bleaching sequence. The increase of ozone stage pH from 2.5 to 7.0 in the sequence Z/DEopD is cost-effective at industrial level because it represents expressive reduction of sulphuric acid and caustic soda demand for pH control in the bleaching plant. These gain areas achieved without any significant changes in pulp quality and effluent load discharge. Nevertheless, the increase of ozone stage pH from 2.5 to 7.0 has a very high negative impact on the efficiency and selectivity for the Z/E and AZ/E processes and it is not recommended in such cases.

  2. Southern Pine Based on Biorefinery Center

    Energy Technology Data Exchange (ETDEWEB)

    Ragauskas, Arthur J. [Georgia Inst. of Technology, Atlanta, GA (United States); Singh, Preet [Georgia Inst. of Technology, Atlanta, GA (United States)

    2013-12-20

    This program seeks to develop an integrated southern pine wood to biofuels/biomaterials processing facility on the Recipient’s campus, that will test advanced integrated wood processing technologies at the laboratory scale, including: The generation of the bioethanol from pines residues and hemicelluloses extracted from pine woodchips; The conversion of extracted woodchips to linerboard and bleach grade pulps; and the efficient conversion of pine residues, bark and kraft cooking liquor into a useful pyrolysis oil.

  3. Anaerobic treatment of cellulose bleach plant wastewater: chlorinated organics and genotoxicity removal

    Directory of Open Access Journals (Sweden)

    T. R. Chaparro

    2011-12-01

    Full Text Available This study assessed the removal efficiency of organic matter and how it relates to the decrease of toxic and mutagenic effects when an anaerobic reactor is used to treat the bleaching effluent from two kraft pulp mills. Parameters such as COD (chemical oxygen demand, DOC (dissolved organic carbon, AOX (adsorbable organic halogen, ASL (acid soluble lignin, color, chlorides, total phenols and absorbance values in the UV-VIS spectral region were measured. The acute and chronic toxicity and genetic toxicity assessments were performed with Daphnia similis, Ceriodaphnia sp. and Allium cepa L, respectively. The removal efficiency of organic matter measured as COD, ranged from 45% to 55%, while AOX removal ranged from 40% to 45%. The acute toxic and chronic effects, as well as the cytotoxic, genotoxic and mutagenic effects, decrease as the biodegradable fraction of the organics is removed. These results, together with the organic load measurement of the effluents of the anaerobic treatment, indicate that these effluents are recalcitrant but not toxic. As expected, color increased when the anaerobic treatment was applied. However, the colored compounds are of microbial origin and do not cause an increase in genotoxic effects. To discharge the wastewater, it is necessary to apply a physico-chemical or aerobic biological post-treatment to the effluents of the anaerobic reactor.

  4. Integrated chemical plants at the pulp mill

    Energy Technology Data Exchange (ETDEWEB)

    Ehtonen, P.; Hurme, M.; Jaervelaeinen, M.

    1995-12-31

    The goal of this paper is to present how the chemical plants can be integrated to the pulp mill. The integration renders possible to balance the chemical consumptions. The total mass balance of a pulp mill with the incoming fuel material and the outgoing waste and flue gases are discussed. The balance figures are presented for the chemicals of the modern fibre line, which will produce fully bleached softwood pulp with an improved effluent quality. The main benefits are lower chemical and transportation costs. The principal over-all plant process block diagrams and process descriptions are presented. The presented info system provides real time information on process and production status at overall mill and department levels. (author)

  5. A comparison of two xylanases from the thermophilic fungi Thielavia terrestris and Thermoascus crustaceus

    Energy Technology Data Exchange (ETDEWEB)

    Gilbert, M [Ottawa Univ., Dept. of Biology, ON (Canada); Yaguchi, M [Inst. for Biological Sciences, National Research Council of Canada, Ottawa, ON (Canada); Watson, D C [Inst. for Biological Sciences, National Research Council of Canada, Ottawa, ON (Canada); Wong, K K.Y. [Chair of Forest Products Biotechnology, Faculty of Forestry, British Columbia Univ., Vancouver, BC (Canada); Breuil, C [Chair of Forest Products Biotechnology, Faculty of Forestry, British Columbia Univ., Vancouver, BC (Canada); Saddler, J N [Chair of Forest Products Biotechnology, Faculty of Forestry, British Columbia Univ., Vancouver, BC (Canada)

    1993-12-01

    Two thermophilic xylanases (xylanase II from Thielavia terrestris 255B and the 32-kDa xylanase from Thermoascus crustaceus 235E) were studied to determine if they had different and complementary modes of action when they hydrolysed various types of xylans. Partial amino acid sequencing showed that these two enzymes belonged to different families of [beta]-1,4-glycanases. Xylanase II achieved faster solubilization of insoluble xylan whereas the 32-kDa xylanase was more effective in producing xylose and short xylooligomers. An assessment of the combined hydrolytic action of the two xylanases did not reveal any co-operative action. The sugars released when the two thermophilic xylanases were used together were almost identical to those released when the 32-kDa xylanase acted alone. The two xyalanses were able to remove about 12% of the xylan remaining in an aspen kraft pulp. This indicated that either one of these thermophilic enzymes may be useful for enhancing the bleaching of kraft pulps. (orig.)

  6. Use of Excel ion exchange equilibrium solver with WinGEMS to model and predict NPE distribution in the Mead/Westvaco Evandale, TX, hardwood bleach plant

    Science.gov (United States)

    Christopher Litvay; Alan Rudie; Peter Hart

    2003-01-01

    An Excel spreadsheet developed to solve the ion-exchange equilibrium in wood pulps has been linked by dynamic data exchange to WinGEMS and used to model the non-process elements in the hardwood bleach plant of the Mead/Westvaco Evandale mill. Pulp and filtrate samples were collected from the diffusion washers and final wash press of the bleach plant. A WinGEMS model of...

  7. Alkaline pulping with additives of date palm rachis and leaves from Sudan.

    Science.gov (United States)

    Khristova, P; Kordsachia, O; Khider, T

    2005-01-01

    Soda-anthraquinone (soda-AQ), alkaline sulphite-anthraquinone (AS-AQ) and alkaline sulphite-anthraquinone-methanol (ASAM) pulping of date palm rachis and leaves from Sudan was carried under different conditions, and pulps with variable yields and mechanical properties were obtained. The date palm rachis gave best yields and mechanical properties with the AS-AQ or the ASAM process, while the leaves were best pulped with the soda method with low yield, but very good strength properties. Blending with 10% and 30% kenaf bark pulp was beneficial, especially for the AS-AQ pulps. Totally chlorine free (TCF) bleached rachis pulps were obtained of high brightness and strength properties suitable for use in writing and printing papers.

  8. Influence of Various Pulp Properties on the Adhesion Between Tissue Paper and Yankee Cylinder Surface

    Directory of Open Access Journals (Sweden)

    Jonna Boudreau

    2014-02-01

    Full Text Available The strength of the adhesion between the paper and the drying Yankee cylinder is of great importance with respect to the final properties of a tissue paper product. Therefore, the effects of a few potentially important pulp properties have been evaluated in laboratory experiments. Four highly different kraft pulps were used, and the adhesion strength was measured by means of the force required when scraping off a paper from a metal surface with a specifically designed knife mounted on a moving cart. The adhesion strength was observed to increase with increasing grammage and increasing degree of beating of the pulp. It was also found that pulps containing more fines, or with higher hemicellulose content, gave rise to higher adhesion strength.

  9. Design and system developments of pulping and paper making equipment for reduction of energy consumption

    Energy Technology Data Exchange (ETDEWEB)

    Panda, A.

    1980-03-15

    Due to unprecedented price rise of energy, acute shortages and uncertainties in securing new and reliable energy sources, continuous technological developments have been taking place in equipment and system design in the field of pulp and paper industry. The possibility of energy reduction in areas of pulping, bleaching and cleaning of pulp, black liquor evaporation, approach flow system and drying of paper are analyzed. Specific energy consumption in terms of both heat and electricity can be considerably reduced by adopting continuous pulping methods, incorporating new concepts of counter-current impregnation, cooking high heat diffusion washing and displacement bleaching. Use of cleaners based on improved design can reduce electric energy use considerably by cleaning pulp at higher consistency and at reduced reject rates without impairing cleaning efficiency. Pre-evaporation of spent liquor in vapor recompression evaporators and use of falling film evaporation for scale forming black liquors can reduce steam demand in evaporation. Specific steam demand in paper drying can be reduced by 6 to 10% using thermo-rings or by modifications of dryer inner surface. Effects of energy consumption by integration of pulp and paper mills and by implementation of effluent treatment program are indicated.

  10. Preparation of lumen-loaded kenaf pulp with magnetite (Fe{sub 3}O{sub 4})

    Energy Technology Data Exchange (ETDEWEB)

    Zakaria, S.; Ong, B.H.; Ahmad, S.H.; Abdullah, M.; Yamauchi, T

    2005-02-15

    Magnetic pulps were prepared from unbleached kenaf (hibiscus cannabinus L.) kraft pulps. Fe{sub 3}O{sub 4} or magnetite powder was used to load into the pulp's lumen and pit. Aluminum sulphate [Al{sub 2}(SO{sub 4}){sub 3}] (alum) and polyethylenimine (PEI), both mainly function as retention aid were used throughout the experiment and found to be beneficial in the preparation of this magnetic pulps. The ash content method was used to determine the amount of magnetite retained in the lumen and pit. The utilization of PEI up to 2% per pulp fibres was found to be the best result on lumen loading. The deposition of magnetite powder in lumen and pit is found decrease as the addition of PEI used is more than 2% per pulp fibres. Scanning electron microscope (SEM) clearly shows the distribution of magnetite deposited in the lumen. Tensile index and folding endurance of the loaded fibre decreased slightly as the percentage of loading pigment increased.

  11. Bleaching in vital deciduous teeth – a clinical case

    Directory of Open Access Journals (Sweden)

    José Carlos Pettorossi Imparato

    2008-01-01

    Full Text Available There has been growing concern and search for esthetic beauty and harmony over the last few years. This concern does not form part ofadults’ lives only, but also of children’s. Among the substances used for bleaching dental structures, the most outstanding are those whoseactive principle is hydrogen peroxide-based . The present study reports a clinical case of a 4-year-old girl that suffered trauma of tooth 61 with consequent color alteration, but with no alteration in pulp vitality. The main complaint by the patient and her guardians concerned esthetics, therefore external dental bleaching was performed, using Opalescence Xtra® (Ultradent, in two sessions with an interval of one month between them. External in office bleaching was the treatment of choice, due to the tooth vitality, patient’s age and presence of only one darkened tooth. After the bleaching treatments an improvement in the darkening was observed, and both the child and her guardians were satisfied with the esthetic result.

  12. 40 CFR 63.446 - Standards for kraft pulping process condensates.

    Science.gov (United States)

    2010-07-01

    ... National Emission Standards for Hazardous Air Pollutants from the Pulp and Paper Industry § 63.446...; (3) Each evaporator system condensate from: (i) The vapors from each stage where weak liquor is introduced (feed stages); and (ii) Each evaporator vacuum system for each stage where weak liquor is...

  13. [Influence of the cycle number in processing of cellulose from waste paper on its ability to hydrolysis by cellulases].

    Science.gov (United States)

    Morozova, V V; Semenova, M V; Rozhkova, A M; Kondrat'eva, E G; Okunev, O N; Bekkarevich, A O; Novozhilov, E V; Sinitsin, A P

    2010-01-01

    Hydrolytic ability of laboratory enzyme preparations from fungus of the Penicillium genus was investigated using kraft pulp from nonbleached softwood and bleached hardwood cellulose as substrates. The enzyme preparations were shown to efficiently hydrolyze both softwood and hardwood cellulose. The yields of glucose and reducing sugars were 24-36 g/l and 27-37 g/l from 100 g/l of dry substrate in 48 h, respectively, and depended on the number of substrate grinding cycles.

  14. Effects of wood polymers and extractives on the adsorption of wet-end chemicals and the properties of the sheet - MPKY 03

    Energy Technology Data Exchange (ETDEWEB)

    Bobacka, V.; Lindholm, J.; Nurmi, M.; Naesman, J. [Aabo Akademi, Turku (Finland). Lab. of Paper Chemistry; Holmbom, B.; Konn, J.; Sundberg, A.; Willfoer, S. [Aabo Akademi, Turku (Finland). Lab. of Forest Products Chemistry

    1998-12-31

    The effects of deposition of dissolved and colloidal substances (disco, DCS) together with fixing agents on the wet end chemistry, and the paper quality have been studied. Increased amounts of wood resin in handsheets results in lower strength properties and friction of the sheets. Addition of isolated polysaccharides together with wood resin results in higher strength properties compared, at the same resin content, to sheets without added polysaccharides. Disco substances released from TMP were adsorbed/deposited onto different fillers. It is possible to determine the distribution of aggregated wood resin in handsheets of kraft pulp by confocal laser scanning microscopy. Addition of iron salts to a TMP suspension results in a decrease in the brightness of the fibers. The adsorption of cationic starch and cationic polyacrylamide was studied as well as the flocculation of a peroxide bleached TMP and mixture of TMP and kraft pulp in the presence of retention aids and fixing agents. The fixing agent had a minor effect on the flocculation in peroxide bleached TMP, while cationic starch induced flocculation after a threshold. When added together, cationic starch induced flocculation immediately. The retention of carbohydrates in the mixture was not much influenced by the presence of fixing agents and retention aids, but the extractives were efficiently retained. Colloidal substances adsorb both cationic starch and polyacrylamide. Of the dissolved substances, pectic acids are most efficiently aggregated. (orig.)

  15. Evaluation of caged freshwater mussels as an alternative method for environmental effects monitoring (EEM) studies

    International Nuclear Information System (INIS)

    Martel, Pierre; Kovacs, Tibor; Voss, Ron; Megraw, Stan

    2003-01-01

    Results from caged mussel experiments agreed with benthic invertebrate surveys, but not with trends observed for fish. - On three occasions between 1998 and 2000, freshwater mussels were collected by divers in Lake Memphremagog during the spring and transplanted to various locations in the St-Francois River (Quebec, Canada). Mussel growth was monitored by comparing total weight and length at the beginning and end of the exposure period. In 1998, mussels were caged for 60 days at 10 stations, including locations receiving treated effluents from three pulp and paper mills. Overall, there was an apparent trend of increased mussel growth from upstream to downstream along the river. However, mussels caged downstream from the effluent discharge of a bleached kraft pulp and paper mill grew more slowly than those caged immediately upstream in the river. In 1999 and 2000, we further investigated the situation in the vicinity of this bleached kraft mill. The measurements again indicated that growth of mussels in the effluent plume from this mill was reduced in comparison to sites upstream. Overall, in terms of growth, the caged mussels responded both positively and negatively to different environmental conditions. Compared with other monitoring approaches used at these sites during the same period, the caged mussel experiment results were consistent with the trends observed with the benthic invertebrate survey but not with the trends observed for fish

  16. Effects of wood polymers and extractives on the adsorption of wet-end chemicals and the properties of the sheet - MPKY 03

    Energy Technology Data Exchange (ETDEWEB)

    Bobacka, V; Lindholm, J; Nurmi, M; Naesman, J [Aabo Akademi, Turku (Finland). Lab. of Paper Chemistry; Holmbom, B; Konn, J; Sundberg, A; Willfoer, S [Aabo Akademi, Turku (Finland). Lab. of Forest Products Chemistry

    1999-12-31

    The effects of deposition of dissolved and colloidal substances (disco, DCS) together with fixing agents on the wet end chemistry, and the paper quality have been studied. Increased amounts of wood resin in handsheets results in lower strength properties and friction of the sheets. Addition of isolated polysaccharides together with wood resin results in higher strength properties compared, at the same resin content, to sheets without added polysaccharides. Disco substances released from TMP were adsorbed/deposited onto different fillers. It is possible to determine the distribution of aggregated wood resin in handsheets of kraft pulp by confocal laser scanning microscopy. Addition of iron salts to a TMP suspension results in a decrease in the brightness of the fibers. The adsorption of cationic starch and cationic polyacrylamide was studied as well as the flocculation of a peroxide bleached TMP and mixture of TMP and kraft pulp in the presence of retention aids and fixing agents. The fixing agent had a minor effect on the flocculation in peroxide bleached TMP, while cationic starch induced flocculation after a threshold. When added together, cationic starch induced flocculation immediately. The retention of carbohydrates in the mixture was not much influenced by the presence of fixing agents and retention aids, but the extractives were efficiently retained. Colloidal substances adsorb both cationic starch and polyacrylamide. Of the dissolved substances, pectic acids are most efficiently aggregated. (orig.)

  17. Pilot study investigating ambient air toxics emissions near a Canadian kraft pulp and paper facility in Pictou County, Nova Scotia.

    Science.gov (United States)

    Hoffman, Emma; Guernsey, Judith R; Walker, Tony R; Kim, Jong Sung; Sherren, Kate; Andreou, Pantelis

    2017-09-01

    Air toxics are airborne pollutants known or suspected to cause cancer or other serious health effects, including certain volatile organic compounds (VOCs), prioritized by the US Environmental Protection Agency (EPA). While several EPA-designated air toxics are monitored at a subset of Canadian National Air Pollution Surveillance (NAPS) sites, Canada has no specific "air toxics" control priorities. Although pulp and paper (P&P) mills are major industrial emitters of air pollutants, few studies quantified the spectrum of air quality exposures. Moreover, most NAPS monitoring sites are in urban centers; in contrast, rural NAPS sites are sparse with few exposure risk records. The objective of this pilot study was to investigate prioritized air toxic ambient VOC concentrations using NAPS hourly emissions data from a rural Pictou, Nova Scotia Kraft P&P town to document concentration levels, and to determine whether these concentrations correlated with wind direction at the NAPS site (located southwest of the mill). Publicly accessible Environment and Climate Change Canada data (VOC concentrations [Granton NAPS ID: 31201] and local meteorological conditions [Caribou Point]) were examined using temporal (2006-2013) and spatial analytic methods. Results revealed several VOCs (1,3-butadiene, benzene, and carbon tetrachloride) routinely exceeded EPA air toxics-associated cancer risk thresholds. 1,3-Butadiene and tetrachloroethylene were significantly higher (p towns and contribute to poor health in nearby communities.

  18. Chemical pulping of waste pineapple leaves fiber for kraft paper production

    Directory of Open Access Journals (Sweden)

    Waham Ashaier Laftah

    2015-07-01

    Full Text Available The main objective of this study is to evaluate the implementation of acetone as a pulping agent for pineapple leaves. Mixtures of water and acetone with concentration of 1%, 3%, 5%, 7%, and 10% were used. The effects of soaking and delignification time on the paper properties were investigated. Thermal and physical properties of paper sheet were studied using thermogravimetric analysis (TGA and tearing resistance test respectively. The morphological properties were observed using microscope at 200× magnification. The paper sheet produced from pulping with 3% acetone concentration shows the highest mechanical properties. Papers strength was improved by increasing the delignification time. The delignification time was reduced by cooking the pineapple leaves at a temperature of 118 °C under applied pressure of 80 kPa which has remarkable effect on paper strength.

  19. Kraft pulp and paper mill wastewater treatment using fixed bed anaerobic reactors

    International Nuclear Information System (INIS)

    Damianovic, M. H. R. Z; Ruas, D.; Pires, E. C.; Foresti, E.

    2009-01-01

    The effluents of pulp mills contain a myriad of toxic compounds, biodegradable organic matter and sulfur compounds. to decrease the amount of fresh water required for pulp and paper production closed circuits are in use, however, higher concentrations of slat, as oxidized sulfur compounds, are encountered in the wastewaters. energy costs and new environmental concerns are motivating the use of anaerobic pretreatment as a way to decrease energy expenditure in the treatment plant together with lower sludge production. In anaerobic environment, the organic matter removal can follow methanogenic or sulfidogenic paths and with the latter simultaneous reduction of the oxidized sulfur compounds also occurs. (Author)

  20. Estratégia de análise da qualidade de madeira de Eucalyptus sp. para produção de celulose A laboratory technique to establish Eucalyptus sp. wood quality for kraft pulp production

    Directory of Open Access Journals (Sweden)

    José Lívio Gomide

    2004-06-01

    Full Text Available Estudou-se uma nova técnica laboratorial de análise de qualidade da madeira de Eucalyptus sp. para produção de polpa celulósica kraft. A técnica consiste em realizar, simultaneamente, quatro cozimentos de cavacos utilizando diferentes cargas de álcali ativo para estabelecer a característica de deslignificação da madeira. Pelo uso de equações de regressão, calcula-se o álcali ativo necessário para obter o número kappa desejado, o rendimento, a viscosidade e álcali consumido para o kappa objetivo. Os estudos estatísticos evidenciaram que uma única batelada de quatro cozimentos é suficiente, não sendo necessário realizar repetições.A new laboratory technique was tested to determine Eucalyptus sp. wood quality for kraft pulp production. This technique consists in performing four cooks simultaneously using different active alkali charges to establish the wood delignification characteristics. Based on regression equation it is possible to determine the alkali charge necessary to obtain a desired kappa number and the yield, viscosity and the alkali consumed for the target kappa. Statistical analysis demonstrated that a set of four cooks without replication is sufficient to determine the wood quality characteristics.

  1. Integration of the Mini-Sulfide Sulfite Anthraquinone (MSS-AQ) Pulping Process and Black Liquor Gasification in a Pulp Mill

    Energy Technology Data Exchange (ETDEWEB)

    Hasan Jameel, North Carolina State University; Adrianna Kirkman, North Carolina State University; Ravi Chandran,Thermochem Recovery International Brian Turk Research Triangle Institute; Brian Green, Research Triangle Institute

    2010-01-27

    As many of the recovery boilers and other pieces of large capital equipment of U.S. pulp mills are nearing the end of their useful life, the pulp and paper industry will soon need to make long-term investments in new technologies. The ability to install integrated, complete systems that are highly efficient will impact the industry’s energy use for decades to come. Developing a process for these new systems is key to the adoption of state-of-the-art technologies in the Forest Products industry. This project defined an integrated process model that combines mini-sulfide sulfite anthraquinone (MSS-AQ) pulping and black liquor gasification with a proprietary desulfurization process developed by the Research Triangle Institute. Black liquor gasification is an emerging technology that enables the use of MSS-AQ pulping, which results in higher yield, lower bleaching cost, lower sulfur emissions, and the elimination of causticization requirements. The recently developed gas cleanup/absorber technology can clean the product gas to a state suitable for use in a gas turbine and also regenerate the pulping chemicals needed to for the MSS-AQ pulping process. The combination of three advanced technologies into an integrated design will enable the pulping industry to achieve a new level of efficiency, environmental performance, and cost savings. Because the three technologies are complimentary, their adoption as a streamlined package will ensure their ability to deliver maximum energy and cost savings benefits. The process models developed by this project will enable the successful integration of new technologies into the next generation of chemical pulping mills. When compared to the Kraft reference pulp, the MSS-AQ procedures produced pulps with a 10-15 % yield benefit and the ISO brightness was 1.5-2 times greater. The pulp refined little easier and had a slightly lower apparent sheet density (In both the cases). At similar levels of tear index the MSS-AQ pulps also

  2. Attenuated total reflection UV spectroscopy for simultaneous analysis of alkali, sulphide and dissolved lignin in pulping liquors

    International Nuclear Information System (INIS)

    Chai, X.S.; Zhu, J.Y.; Luo, Q.; Li, J.

    2003-01-01

    This study experimentally demonstrated attenuated total reflection (ATR) ultraviolet (UV) spectroscopy for rapid and simultaneous determination of the concentrations of hydroxide, sulphide and dissolved lignin in kraft pulping liquors. A multivariate partial least squares fitting procedure (using commercially available software) was employed to obtain the species concentrations from the measured absorption spectra of the pulping liquors. Good agreements between ATR-UV measured species concentrations and those obtained by reference methods (titration for hydroxide and sulphide and conventional UV absorption for dissolved lignin) were achieved. (author)

  3. Green liquor impregnation and Kraft pulping of South African Pinus Patula – “A practical approach to provide cost savings in a Kraft mill’s pulping operation”

    CSIR Research Space (South Africa)

    Johakimu, Jonas K

    2011-02-01

    Full Text Available . Singh J., Ragauskas A.R., Lucia L.A., (2002). ?Green Liquor Chip Pre- treatment as a Feasible Method for the Enhancement of Softwood Pulp Chemical Properties. Journal of wood Chemistry and Technology. 2: 173-181. 5. Gordon Broderick...

  4. Hygroscopic slaking of lime with steam or humid air. New energy effective lime slaking technology in kraft pulping; Hygroskopisk slaeckning av kalk med aanga eller fuktig luft. Ny energieffektiv teknik foer slaeckning av mesakalk i sulfatmassaindustrin

    Energy Technology Data Exchange (ETDEWEB)

    Lundqvist, Roland

    2003-07-15

    Lime stone is widely used in chemical recovery for regeneration of white liquor in kraft pulping. Slaked (hydrated) lime is used to convert (causticize) sodium carbonate into sodium hydroxide, whereby lime mud (calcium carbonate) precipitates from the solution. Lime mud is dried and reburned in a lime kiln, where burned lime (calcium oxide) is formed. The circle is closed when lime is slaked (hydrated) in green liquor in an exotherm reaction. Problems with traditional slaking method is that heat is recovered at low temperatures. With the method described in this report there is potential to increase heat recovery in the causticizing plant. The forecasted method means that lime is slaked with steam or humid air, for example combined with a lime mud drier and a lime kiln. The task has included slaking of burned lime with steam or humid hot air, on purpose to test a specific machine equipment in pilote scale, and to investigate temperatures and hydratization rates able to reach. Also the lime slaked with steam/humid air should be compared with burned lime slaked in green liquor when green liquor is causticized, and to investigate the dewatering properties of formed lime mud. The target group is pulp and paper industry using the kraft process. The tests have been performed at SMA Svenska Mineral AB plant (lime burning) at Sandarne Sweden in years 2004-2005. Project owner has been the Swedish company Torkapparater AB, and the project is performed inside the 'Vaermeforsk Program for Pulp and Paper Industry 2004-2005'. Other partners, besides SMA Svenska Mineral AB, has been Stora Enso Skoghalls Bruk, Carnot AB, AaF Process AB and KTH Energiprocesser. Hydrated lime of varying slaking rates has been produced at temperatures up to 270 deg C. Caustizicing being performed show that dewatering properties of lime mud formed is quite up to the standard of lime mud from burned lime slaked in green liquor. The apprehension, that the hygroscopic slaked lime should result

  5. Hygroscopic slaking of lime with steam or humid air. New energy effective lime slaking technology in kraft pulping; Hygroskopisk slaeckning av kalk med aanga eller fuktig luft. Ny energieffektiv teknik foer slaeckning av mesakalk i sulfatmassaindustrin

    Energy Technology Data Exchange (ETDEWEB)

    Lundqvist, Roland

    2005-12-15

    Lime stone is widely used in chemical recovery for regeneration of white liquor in kraft pulping. Slaked (hydrated) lime is used to convert (causticize) sodium carbonate into sodium hydroxide, whereby lime mud (calcium carbonate) precipitates from the solution. Lime mud is dried and reburned in a lime kiln, where burned lime (calcium oxide) is formed. The circle is closed when lime is slaked (hydrated) in green liquor in an exotherm reaction. Problems with traditional slaking method is that heat is recovered at low temperatures. With the method described in this report there is potential to increase heat recovery in the causticizing plant. The forecasted method means that lime is slaked with steam or humid air, for example combined with a lime mud drier and a lime kiln. The task has included slaking of burned lime with steam or humid hot air, on purpose to test a specific machine equipment in pilote scale, and to investigate temperatures and hydratization rates able to reach. Also the lime slaked with steam/humid air should be compared with burned lime slaked in green liquor when green liquor is causticized, and to investigate the dewatering properties of formed lime mud. The target group is pulp and paper industry using the kraft process. The tests have been performed at SMA Svenska Mineral AB plant (lime burning) at Sandarne Sweden in years 2004-2005. Hydrated lime of varying slaking rates has been produced at temperatures up to 270 deg C. Caustizicing being performed show that dewatering properties of lime mud formed is quite up to the standard of lime mud from burned lime slaked in green liquor. The apprehension, that the hygroscopic slaked lime should result in lime mud difficult to dewater, has not become true. Important experiences have come out which could be used as a base in further investigations.

  6. Failure analysis of a heat exchanger used of a wood pulp bleaching process; Analise de falha de um trocador de calor utilizado no processo de branqueamento da polpa de celulose

    Energy Technology Data Exchange (ETDEWEB)

    Castro, D.B.V.; Moreto, J.A.; Rossino, L.S.; Spinelli, D.; Tarpani, J.R. [Universidade de Sao Paulo (SMM/EESC/USP), Sao Carlos, SP (Brazil). Escola de Engenharia. Dept. de Engenharia de Materais, Aeronautica e Automobilistica

    2010-07-01

    This study involved an investigation of the failure of a heat exchanger used in the ozone destruction stage of a wood pulp bleaching process at a pulp plant. The following procedures were carried out to determine the causes of the failure: a chemical analysis of the component, atomic absorption spectroscopy, measurements of hardness and of corrosion-related mass loss, characterization by scanning electron microscopy, and chemical microanalysis by X-ray energy dispersive spectroscopy. The corrosion damage of the heat exchanger was caused by chloric and sulfuric acid, which led to pitting, grooving and cracking, as well as generalized corrosion of the component (AISI 316L steel). Nitric acid caused minimal damage to the heat exchanger, with minor generalized corrosion and occasional pitting. White crystals rich in sulfur and chlorine were identified as the corrosive agents acting inside the heat exchanger. (author)

  7. Evaluation of Pulp and Paper Properties obtained from Maple Juvenile Wood through Organosolv Alcohol Method Catalyzed by Calcium and Magnesium Salts

    Directory of Open Access Journals (Sweden)

    Reza Naghdi

    2015-05-01

    Full Text Available The properties of catalyzed organosolv pulp obtained from maple juvenile wood were studied. The physical properties of fiber (e.g. length, width, and cell membrane thickness and chemical composition of maple juvenile wood (e.g. average cellulose, lignin, extractives, and ash content were determined. The variables were cooking temperature (190 and 200 ºC and time (40, 60, and 80 minutes. Chemical charge ( 280 ml methanol, 70 ml water, and 0.025 mols of Calcium Chloride and Magnesium Nitrate was kept constant. Pulp screen yields (54.9 to 60.91% and Kappa No. (15.5 to 18.4 were measured. Pulp freeness was reduced to 350 ml CSF in PFI mill, and ten 60 g/m2 handsheets were made from the selected pulps. The strength properties of catalyzed organosolv handsheets including tear length (3.83 to 4.25 km, tear index (10.22 to 12.81 mN.m2/g, and burst index (1.74 to 2.15 kPa.m2/g were compared with those of the conventional Kraft handsheets of maple juvenile wood. The least allowed values of the mentioned properties in the Indian (IS and Japanese international standards (JIS reveal that while the tear length value is slightly below that of the standards, the values of tear and burst indices are well beyond the given standards, and the environmentally-friendly catalyzed organosolv pulping process (higher yield and lower Kappa No. compared to Kraft can be recommended to produce paper pulp from maple juvenile wood.

  8. High consistency cellulase treatment of hardwood prehydrolysis kraft based dissolving pulp.

    Science.gov (United States)

    Wang, Qiang; Liu, Shanshan; Yang, Guihua; Chen, Jiachuan; Ni, Yonghao

    2015-01-01

    For enzymatic treatment of dissolving pulp, there is a need to improve the process to facilitate its commercialization. For this purpose, the high consistency cellulase treatment was conducted based on the hypothesis that a high cellulose concentration would favor the interactions of cellulase and cellulose, thus improves the cellulase efficiency while decreasing the water usage. The results showed that compared with a low consistency of 3%, the high consistency of 20% led to 24% increases of cellulase adsorption ratio. As a result, the viscosity decrease and Fock reactivity increase at consistency of 20% were enhanced from 510 mL/g and 70.3% to 471 mL/g and 77.6%, respectively, compared with low consistency of 3% at 24h. The results on other properties such as alpha cellulose, alkali solubility and molecular weight distribution also supported the conclusion that a high consistency of cellulase treatment was more effective than a low pulp consistency process. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. A LARCH BIOREFINERY: INFLUENCE OF WASHING AND PS CHARGE ON PRE-EXTRACTION PSAQ PULPING

    Directory of Open Access Journals (Sweden)

    Hanna S. Hörhammer

    2012-06-01

    Full Text Available This study deals with a biorefinery concept based on larch wood. Wood chips of Siberian larch (Larix sibirica Lebed. were treated with water before pulping at the optimal pre-extraction (PE condition of 150 °C and 90 minutes. Through PE, about 12.4% of the wood mass is dissolved, mainly from the arabinogalactan hemicellulose component. Fermentation of the hemicellulose-rich larch extract with Bacillus coagulans resulted in consumption of all C6 and C5 sugars and produced lactic acid in high yield. PE before pulping resulted in lower (4 to 5% pulp yield than for control kraft pulps. However, the pulp yield loss may be reduced by addition of polysulfide (PS and anthraquinone (AQ. The present study focuses on the effect of the degree of washing of the extracted chips and that of the PS charge in PSAQ pulping on the final properties of the pulp. Three different levels of washing and three different PS charges were tested. The characteristics of the extract, wash water, pulp, and black liquor samples were determined. The amount of sugars in the combined stream of collected extract and wash water obtained by mild washing was 10.2% on o.d. wood.

  10. Heterogeneous studies in pulping of wood: Modelling mass transfer of alkali

    OpenAIRE

    Simão, João P. F.; Egas, Ana P. V.; Carvalho, M. Graça; Baptista, Cristina M. S. G.; Castro, José Almiro A. M.

    2008-01-01

    In this paper a heterogeneous lumped parameter model is proposed to describe the mass transfer of effective alkali during the kraft pulping of wood. This model, based on the spatial mean of the concentration profile of effective alkali along the chip thickness, enables the estimation of the effective diffusion coefficient that characterizes the internal resistance to mass transfer and the contribution of the external resistance to mass transfer which has often been neglected. http://www.sc...

  11. AVALIAÇÃO DOS RESÍDUOS DE UMA SERRARIA PARA A PRODUÇÃO DE CELULOSE KRAFT

    Directory of Open Access Journals (Sweden)

    Lucas Cândido Barbosa

    2014-01-01

    Full Text Available The forest-based industries have low yield and generate large amounts of waste, especially the primary processing industries, such as sawmills. In Brazil, initiatives are being created to combine the use of sawmill residues to pulp production. With this in mind, this study aimed to evaluate the performance of amedium-sized sawmill in the city of Rio Grande, in Rio Grande do Sul state, and to promote physical and chemical analysis of waste wood generated in the sawing process. It was used 20 logs of Pinus elliottii , divided into two diameter classes. The residues, except the sawdust, collected for analysis were disposed in the courtyard of the company in the form of chips. The following physical and chemical properties of the chips were examined: density, extractives content soluble in acetone, acetyl groups, soluble and insoluble lignin on acid (Klason lignin, uronic groups and carbohydrates. Comparing the results of the wood properties to the ones found in literature, it was evaluated the quantity and quality of waste that can be used as feedstock for the production of kraft pulp. As the main results there was a slight increase of sawing yields in the larger diameters logs compared to the smaller diameters. From the physical and chemical analyses, it was obtained the following results: density of 0.402 g / cm ³, cellulose content of 43.67% and 24.37% for hemicellulose, klason lignin of 26.75% and 3,80% for extractives content. As conclusion, the low sawing yield can be associated to the lack of a classification diametric and appropriate diagrams sections, resulting in a greater loss in the form of waste. Regarding the chemical and physical composition of the sawmill residues, the results were within the standards of quality wood used for kraft pulp of softwood material, presenting some advantages over younger woods commonly used in industry.

  12. Colorimeter and scanning electron microscopy analysis of teeth submitted to internal bleaching.

    Science.gov (United States)

    Martin-Biedma, Benjamin; Gonzalez-Gonzalez, Teresa; Lopes, Manuela; Lopes, Luis; Vilar, Rui; Bahillo, José; Varela-Patiño, Purificación

    2010-02-01

    This in vitro study compared the tooth color and the ultrastructure of internal dental tissues before and after internal bleaching. Sodium perborate was placed in the pulp chamber of endodontically treated molars and sealed with intermediate restorative material. The test samples were stored in a physiologic solution, and the bleaching agent was replaced every 7 days. A control group was used. After 1 month, the colors of the test and control samples were measured with a colorimeter, and the internal surfaces were observed under field emission scanning electron microscopy (FESEM). Statistically significant differences were found between the test and control sample colors. The FESEM ultrastructure analysis of the internal enamel and dentin surfaces did not show any changes after the internal bleaching. The results of the present study show that sodium perborate is effective in bleaching nonvital teeth and does not produce ultrastructural changes in the dental tissues. Copyright 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  13. Application of cellulosic nanofibers to replace with imported long- fiber pulps in paper made from bagasse

    Directory of Open Access Journals (Sweden)

    Reza ghofran

    2017-02-01

    Full Text Available In this research, different additives of cellulose nanofibers, cationic starch and polyacrylamide to bagasse pulp and their impact on the handsheet strengths were investigated aiming to replace with imported long-fiber softwood pulp in Pars paper factory. For this purpose, first 3% bleached bagasse cellulose nanofibers, 3% unbleached nano-lignocellulosic fibers, 0.5, 0.7 and 1% cationic starch, and 0.03, 0.05 and 0.1% cationic polyacrylamide were added separately to bagasse pulp. In the next stage,3% bleached bagasse cellulose nanofibers and 3% unbleached nano-lignocellulosic fibers along with 0.5% cationic starch or 0.05% cationic polyacrylamide were used. The results showed, adding nano-cellulose fibers along with cationic polyacrylamide or starch have increased handsheet strengths significantly. Yet, the best treatment was the addition of 3% nano-lignocellulose along with 0.5% cationic starch which resulted in the higher tensile and burst strengths and lower tear and fold strengths than that of adding 12.5% long fibers to bagasse pulp. So that, comparing with paper made from pure bagasse pulp it showed the increase of 16.57% in tensile index, 8.47% in burst index, 9.77% in tear index, and 168.85% in folding strength.

  14. Cellulose fibril aggregation studies of Eucalyptus dissolving pulps using atomic force microscopy

    CSIR Research Space (South Africa)

    Chunilall, Viren

    2006-11-01

    Full Text Available , P.T. (2006), 9th European Workshop on Lignocellulosics and Pulp, Conference Proceedings. 3. Nocanda, X. et al. (2007), Holzforschung, 61(6), 675. 4. Krässig, H. A., (1996) Polymer Monographs, 11. Figure 1. Fully bleached 92 ! (freeze dried...

  15. New alternative energy pathway for chemical pulp mills: From traditional fibers to methane production.

    Science.gov (United States)

    Rodriguez-Chiang, Lourdes; Vanhatalo, Kari; Llorca, Jordi; Dahl, Olli

    2017-07-01

    Chemical pulp mills have a need to diversify their end-product portfolio due to the current changing bio-economy. In this study, the methane potential of brown, oxygen delignified and bleached pulp were evaluated in order to assess the potential of converting traditional fibers; as well as microcrystalline cellulose and filtrates; to energy. Results showed that high yields (380mL CH 4 /gVS) were achieved with bleached fibers which correlates with the lower presence of lignin. Filtrates from the hydrolysis process on the other hand, had the lowest yields (253mL CH 4 /gVS) due to the high amount of acid and lignin compounds that cause inhibition. Overall, substrates had a biodegradability above 50% which demonstrates that they can be subjected to efficient anaerobic digestion. An energy and cost estimation showed that the energy produced can be translated into a significant profit and that methane production can be a promising new alternative option for chemical pulp mills. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Energy efficiency improvement of a Kraft process through practical stack gases heat recovery

    International Nuclear Information System (INIS)

    Mostajeran Goortani, B.; Mateos-Espejel, E.; Moshkelani, M.; Paris, J.

    2011-01-01

    A process scheme for the optimal recovery of heat from stack gases considering energy and technical constraints has been developed and applied to an existing Kraft pulping mill. A system based on a closed loop recirculation of hot oil is used to recover the heat from stack gases and distribute it to the appropriate cold streams. The recovery of heat from stack gases is part of an overall optimization of the Kraft mill. Tools such as Pinch Analysis and exergy analysis are used to evaluate the process streams. The results indicate that 10.8 MW of heat from stack gases can be reused to heat process streams such as the deaerator water, hot water, drying filtrates, and black liquor. A simulation model of the recirculation loop has been developed to determine the specifications of the recovery system. The total heat exchanger surface area required by the system is 3460 m 2 , with a hot oil recirculation temperature of 137 o C. The anticipated total investment is $10.3 M, with a payback time of 1.8 years. - Highlights: → We developed a process design for recovering heat from stack gases in a Kraft mill. → The recovered heat is optimally distributed to the process cold streams. → Heat recovery system has a total surface area of 3500 m 2 without gases condensation. → A reduction of 7 percent in total process steam demand is anticipated. → A total investment of 10.3 M$ is needed with a payback time of less than two years

  17. The influence of irradiation of gamma-rays on the pulping and paper making, (4)

    International Nuclear Information System (INIS)

    Suzuki, Kyoji; Inoue, Kaoru; Hanamura, Norio; Mori, Kenji

    1980-01-01

    The influence of gamma-irradiation on the beating properties of unbleached kraft pulps was studied, and the changes of the mechanical and chemical properties of the sheet made from those pulps were also investigated. The results obtained were as follows: (1) When the unbeaten pulp was treated with gamma-ray, the degree of polymerization of cellulose was decreased rapidly and the formation of aldehyde and carboxyl groups in pulp was observed in addition to that the beating time of irradiated pulps was reduced comparing with non-irradiated pulp. These effects increased roughly in proportion to the radiation dose. (2) Gamma-irradiation was more effective in wet state (moisture content = 70 - 80%) than air dry state. This may be due to the degradation products of water by gamma-irradiation. (3) The mechanical properties (breaking length, tear and burst factors) of the sheets made from irradiated pulps were considerably deteriorated at 10 7 R, but there was a slight deterioration up to 10 6 R. (4) Comparing the result of the mechanical properties, the strengths of the various sheets were shown in the following order: the sheet irradiated after paper making gt the sheet irradiated before beating (air dry state) gt the sheet irradiated before beating (wet state). (author)

  18. Penetration of 35% hydrogen peroxide into the pulp chamber in bovine teeth after LED or Nd:YAG laser activation.

    Science.gov (United States)

    Camargo, Samira Esteves Afonso; Cardoso, Paula Elaine; Valera, Marcia Carneiro; de Araújo, Maria Amélia Máximo; Kojima, Alberto Noriyuki

    2009-01-01

    This aim of the present study was to evaluate the pulp chamber penetration of 35% hydrogen peroxide activated by LED (light-emitting diode) or Nd:YAG laser in bovine teeth, after an in-office bleaching technique. Forty-eight bovine lateral incisors were divided into four groups, acetate buffer was placed into the pulp chamber and bleaching agent was applied as follows: for group A (n = 12), activation was performed by LED; for group B (n = 12), activation was performed by Nd:YAG laser (60 mJ, 20 Hz); group C (n = 12) received no light or laser activation; and the control group (n = 12) received no bleaching gel application or light or laser activation. The acetate buffer solution was transferred to a glass tube and Leuco Crystal Violet and horseradish peroxidase were added, producing a blue solution. The optical density of this solution was determined spectrophotometrically and converted into microgram equivalents of hydrogen peroxide. The results were analysed using ANOVA and Tukey's test (5%). It was verified that the effect of activation was significant, as groups activated by LED or laser presented greater hydrogen peroxide penetration into the pulp chamber (0.499 +/- 0.622 microg) compared with groups that were not (0.198 +/- 0.218 microg). There was no statistically significant difference in the penetration of hydrogen peroxide into the pulp chamber between the two types of activation (LED or laser). The results suggest that activation by laser or LED caused an increase in hydrogen peroxide penetration into the pulp chamber.

  19. Effect of Bagasse Chemical Pulping and Coupling Agent on the Physical - Mechanical Properties of Composites Based on Bagasse pulp/Low density polyethylene

    Directory of Open Access Journals (Sweden)

    maryam allahdadi

    2016-12-01

    Full Text Available In this research, effect of reinforcing bagasse pulp and raw bagasse fibers and applying coupling agent MAPE (Maleic Anhydride Polyethylene on physical-mechanical properties of low density polyethylene (LDPE composites were studided. Fresh bagasse were collected from an experimental field in Khuzestan and after investigating anatomy and chemical properties of Different pulp fibers including monoethanolamine (MEA bagasse pulp, alkaline sulfite-anthraquinone (AS bagasse pulp, bleached soda (BS bagasse pulp, unbleached soda (UNS bagasse pulp and raw bagasse fibers (B were prepared. Then, composites with 30wt.% fiber content were manufactured by twin-screw extrusion followed by compression molding processing. The mechanical and physical properties of these composites were analyzed and compared. Results revealed that the chemical pulping dissolved a fraction of lignin and hemicelluloses so that the linkage potential and aspect ratio of bagasse fibers was improved and consequently, as compared with the raw bagasse fibers, bagasse pulp fibers have better reinforcing capability. The best overall properties were achieved with MEA and AS/AQ fibers. Addition of 5% (wt/wt of coupling agent MAPE resulted in a significant enhancement in the tensile strength, tensile modulus and impact strength in line with the improvement of the fiber-matrix interfacial adhesion making more effective the transfer of stress from the matrix to the rigid reinforcement.

  20. Cationic polyacrylamide enhancing cellulase treatment efficiency of hardwood kraft-based dissolving pulp.

    Science.gov (United States)

    Wang, Qiang; Liu, Shanshan; Yang, Guihua; Chen, Jiachuan; Ni, Yonghao

    2015-05-01

    Cellulase treatment for decreasing viscosity and increasing Fock reactivity of dissolving pulp is a promising approach to reduce the use of toxic chemicals, such as hypochlorite in the dissolving pulp manufacturing process in the industry. Improving the cellulase treatment efficiency during the process is of practical interest. In the present study, the concept of using cationic polyacrylamide (CPAM) to enhance the cellulase treatment efficiency was demonstrated. This was mainly attributed to the increased cellulase adsorption onto cellulose fibers based on the patching/bridging mechanism. Results showed that the cellulase adsorption was increased by about 20% with the addition of 250 ppm of CPAM under the same conditions as those of the control. It was found that the viscosity decrease and Fock reactivity increase for the cellulase treatment was enhanced from using CPAM. The CPAM-assisted cellulase treatment concept may provide a practical alternative to the present hypochlorite-based technology for viscosity control in the industry. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Fracture resistance of endodontically-treated teeth: effect of combination bleaching and an antioxidant.

    Science.gov (United States)

    Khoroushi, Maryam; Feiz, Atieh; Khodamoradi, Roghayeh

    2010-01-01

    This in vitro study assessed the fracture resistance of endodontically-treated teeth undergoing combination bleaching with 38% and 9.5% hydrogen peroxide gels as in-office and at-home bleaching techniques, respectively. In addition, the effect of an antioxidizing agent, sodium ascorbate, was investigated. Sixty maxillary premolars were endodontically-treated, received a glass ionomer barrier as a mechanical seal and were embedded in acrylic resin up to the cemento-enamel junction. The specimens were divided into four groups (n = 15) as follows: G I: no bleaching, access cavity restored with resin composite (negative control); G II: bleached for three weeks daily using 9.5% hydrogen peroxide for two hours and three sessions of in-office bleaching using 38% hydrogen peroxide every seven days, then restored (positive control); G III: bleached similar to G II and restored after one week; G IV: bleached similar to G II, along with the use of an antioxidizing agent for 24 hours, then restored. In each in-office and at-home bleaching session, the whitening gels were applied to the buccal surface of the tooth and placed inside the pulp chamber (inside/outside bleaching technique). Finally, the specimens underwent fracture resistance testing; the data were analyzed using ANOVA and Scheffé's test (alpha = 0.05). Significant differences were observed among the study groups (p 0.05). Within the limitations of the current study, it can be concluded that the fracture resistance of endodontically-treated teeth decreases after combination bleaching. The use of sodium ascorbate can reverse decreased fracture resistance.

  2. EXTRACELLULAR PROTEINS PRODUCED BY DIFFERENT SPECIES OF THE FUNGUS TRICHODERMA ON SECONDARY PAPER MILL SLUDGE SUBSTRATE

    Directory of Open Access Journals (Sweden)

    Ida Vaskova,

    2012-01-01

    Full Text Available Kraft pulping is the most commonly used pulping process in the pulp and paper industry. In this process wood chips are chemically delignified using sodium sulfide and sodium hydroxide. Delignification is usually followed by mechanical fiberization and a bleaching process of the resulting wood pulp. In addition to lignin-free wood pulp, this process also produces waste that contains residues of used chemicals, lignin, cellulose, hemicelluloses, and small amounts of other wood components. Because of the worldwide large-scale production of paper, the sludge from paper mills contributes significantly to environmental pollution. Although there have been great efforts being made to utilize this lignin-rich material, sludge is mostly disposed in landfills or incinerated in a boiler. This research project used secondary sludge as a substrate for 7 wood-decay fungi taxonomically belonging to the genus Trichoderma. The examined fungi expressed the capability of consuming sludge components as a carbon source to produce extracellular proteins. The proteins were separated by gel electrophoresis. Before and after fungi cultivation, the sludge was analyzed by Fourier transform infrared spectroscopy (FTIR.

  3. Chemical pulping of waste pineapple leaves fiber for kraft paper production

    OpenAIRE

    Laftah, Waham Ashaier; Abdul Rahaman, Wan Aizan Wan

    2015-01-01

    The main objective of this study is to evaluate the implementation of acetone as a pulping agent for pineapple leaves. Mixtures of water and acetone with concentration of 1%, 3%, 5%, 7%, and 10% were used. The effects of soaking and delignification time on the paper properties were investigated. Thermal and physical properties of paper sheet were studied using thermogravimetric analysis (TGA) and tearing resistance test respectively. The morphological properties were observed using microscope...

  4. Generation of Hydrogen, Lignin and Sodium Hydroxide from Pulping Black Liquor by Electrolysis

    Directory of Open Access Journals (Sweden)

    Guangzai Nong

    2015-12-01

    Full Text Available Black liquor is generated in Kraft pulping of wood or non-wood raw material in pulp mills, and regarded as a renewable resource. The objective of this paper was to develop an effective means to remove the water pollutants by recovery of both lignin and sodium hydroxide from black liquor, based on electrolysis. The treatment of a 1000 mL of black liquor (122 g/L solid contents consumed 345.6 kJ of electric energy, and led to the generation of 30.7 g of sodium hydroxide, 0.82 g of hydrogen gas and 52.1 g of biomass solids. Therefore, the recovery ratios of elemental sodium and biomass solids are 80.4% and 76%, respectively. Treating black liquor by electrolysis is an environmentally friendly technology that can, in particular, be an alternative process in addressing the environmental issues of pulping waste liquor to the small-scale mills without black liquor recovery.

  5. HIGHLY ENERGY EFFICIENT D-GLU (DIRECTED-GREEN LIQ-UOR UTILIZATION) PULPING

    Energy Technology Data Exchange (ETDEWEB)

    Lucia, Lucian A

    2013-04-19

    Purpose: The purpose of the project was to retrofit the front end (pulp house) of a commercial kraft pulping mill to accommodate a mill green liquor (GL) impregna-tion/soak/exposure and accrue downstream physical and chemical benefits while prin-cipally reducing the energy footprint of the mill. A major player in the mill contrib-uting to excessive energy costs is the lime kiln. The project was intended to offload the energy (oil or natural gas) demands of the kiln by by-passing the causticization/slaking site in the recovery area and directly using green liquor as a pulping medium for wood. Scope: The project was run in two distinct, yet mutually compatible, phases: Phase 1 was the pre-commercial or laboratory phase in which NC State University and the Insti-tute of Paper Science and Technology (at the Georgia Institute of Technology) ran the pulping and associated experiments, while Phase 2 was the mill scale trial. The first tri-al was run at the now defunct Evergreen Pulp Mill in Samoa, CA and lead to a partial retrofit of the mill that was not completed because it went bankrupt and the work was no longer the low-hanging fruit on the tree for the new management. The second trial was run at the MeadWestvaco Pulp Mill in Evedale, TX which for all intents and pur-poses was a success. They were able to fully retrofit the mill, ran the trial, studied the pulp properties, and gave us conclusions.

  6. Spectroscopic determination of anthraquinone in kraft pulping liquors using a membrane interface

    Science.gov (United States)

    X.S. Chai; X.T. Yang; Q.X. Hou; J.Y. Zhu; L.-G. Danielsson

    2003-01-01

    A spectroscopic technique for determining AQ in pulping liquor was developed to effectively separate AQ from dissolved lignin. This technique is based on a flow analysis system with a Nafion membrane interface. The AQ passed through the membrane is converted into its reduced form, AHQ, using sodium hydrosulfite. AHQ has distinguished absorption characteristics in the...

  7. Laccase from Pycnoporus cinnabarinus and phenolic compounds: can the efficiency of an enzyme mediator for delignifying kenaf pulp be predicted?

    Science.gov (United States)

    Andreu, Glòria; Vidal, Teresa

    2013-03-01

    In this work, kenaf pulp was delignified by using laccase in combination with various redox mediators and the efficiency of the different laccase–mediator systems assessed in terms of the changes in pulp properties after bleaching. The oxidative ability of the individual mediators used (acetosyringone, syringaldehyde, p-coumaric acid, vanillin and actovanillone) and the laccase–mediator systems was determined by monitoring the oxidation–reduction potential (ORP) during process. The results confirmed the production of phenoxy radicals of variable reactivity and stressed the significant role of lignin structure in the enzymatic process. Although changes in ORP were correlated with the oxidative ability of the mediators, pulp properties as determined after the bleaching stage were also influenced by condensation and grafting reactions. As shown here, ORP measurements provide a first estimation of the delignification efficiency of a laccase–mediator system. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Production of cellulose nanofibrils from bleached eucalyptus fibers by hyperthermostable endoglucanase treatment and subsequent microfluidization

    Science.gov (United States)

    Wangxia Wang; Michael D. Mozuch; Ronald C. Sabo; Phil Kersten; J.Y. Zhu; Yongcan Jin

    2015-01-01

    A GH5 hyperthermostable endoglucanase from the archaeon Pyrococcus honkoshii (ph-GH5) and a commercial endoglucanase FR were used to treat bleached eucalyptus pulp (BEP) fibers to produce cellulose nanofibrils (CNFs) through subsequent microfluidization Enzymatic treatments facilitated CNF production due to the reduced degree of polymerization (DP)...

  9. Development of a strategy for energy efficiency improvement in a Kraft process based on systems interactions analysis

    Science.gov (United States)

    Mateos-Espejel, Enrique

    The objective of this thesis is to develop, validate, and apply a unified methodology for the energy efficiency improvement of a Kraft process that addresses globally the interactions of the various process systems that affect its energy performance. An implementation strategy is the final result. An operating Kraft pulping mill situated in Eastern Canada with a production of 700 adt/d of high-grade bleached pulp was the case study. The Pulp and Paper industry is Canada's premier industry. It is characterized by large thermal energy and water consumption. Rising energy costs and more stringent environmental regulations have led the industry to refocus its efforts toward identifying ways to improve energy and water conservation. Energy and water aspects are usually analyzed independently, but in reality they are strongly interconnected. Therefore, there is a need for an integrated methodology, which considers energy and water aspects, as well as the optimal utilization and production of the utilities. The methodology consists of four successive stages. The first stage is the base case definition. The development of a focused, reliable and representative model of an operating process is a prerequisite to the optimization and fine tuning of its energy performance. A four-pronged procedure has been developed: data gathering, master diagram, utilities systems analysis, and simulation. The computer simulation has been focused on the energy and water systems. The second stage corresponds to the benchmarking analysis. The benchmarking of the base case has the objectives of identifying the process inefficiencies and to establish guidelines for the development of effective enhancement measures. The studied process is evaluated by a comparison of its efficiency to the current practice of the industry and by the application of new energy and exergy content indicators. The minimum energy and water requirements of the process are also determined in this step. The third stage is

  10. Extraction of hemicelluloses from wood in a pulp biorefinery, and subsequent fermentation into ethanol

    International Nuclear Information System (INIS)

    Boucher, Jérémy; Chirat, Christine; Lachenal, Dominique

    2014-01-01

    Highlights: • Hemicellulosic ethanol from softwood hemicelluloses in a pulp mill. • Comparison of acid hydrolysis and autohydrolysis to extract hemicelluloses. • Effects of the extraction process conditions on inhibitors concentrations. • Effects of inhibitors on fermentation. - Abstract: This study deals with the production of ethanol and paper pulp in a kraft pulp mill. The use of an acid hydrolysis or a two-step treatment composed of an autohydrolysis followed by a secondary acid hydrolysis was studied. Acid hydrolysis allowed the extraction of higher quantities of sugars but led also to higher degradations of these sugars into inhibitors of fermentation. The direct fermentation of a hydrolysate resulting from an acid hydrolysis gave excellent yields after 24 h. However, the fermentation of hydrolysates after their concentration proved to be impossible. The study of the impact of the inhibitors on the fermentations showed that organic acids, and more specifically formic acid and acetic acid were greatly involved in the inhibition

  11. Kinetics of pulp mill effluent treatment by ozone-based processes

    International Nuclear Information System (INIS)

    Ko, Chun-Han; Hsieh, Po-Hung; Chang, Meng-Wen; Chern, Jia-Ming; Chiang, Shih-Min; Tzeng, Chewn-Jeng

    2009-01-01

    The wastewaters generated from wood pulping and paper production processes are traditionally treated by biological and physicochemical processes. In order to reduce chemical oxygen demand (COD) and color to meet increasingly strict discharge standards, advanced oxidation processes (AOPs) are being adapted as polishing treatment units. Various ozone-based processes were used in this study to treat simulated wastewaters prepared from black liquor from a hardwood Kraft pulp mill in Taiwan. The experimental results showed that the COD and color were primarily removed by direct ozone oxidation and activated carbon adsorption. While the addition of activated carbon could enhance the COD and color removal during ozonation, the addition of hydrogen peroxide improved the color removal only. For the various ozone-based treatment processes, kinetic models were developed to satisfactorily predict the COD and color removal rates. According to the kinetic parameters obtained from the various ozone-based processes, the enhanced COD and color removal of ozonation in the presence of activated carbon was attributed to the regeneration of the activated carbon by ozonation. These kinetic models can be used for reactor design and process design to treat pulping wastewater using ozone-based processes.

  12. Treatment of the Bleaching Effluent from Sulfite Pulp Production by Ceramic Membrane Filtration

    OpenAIRE

    Ebrahimi, Mehrdad; Busse, Nadine; Kerker, Steffen; Schmitz, Oliver; Hilpert, Markus; Czermak, Peter

    2015-01-01

    Pulp and paper waste water is one of the major sources of industrial water pollution. This study tested the suitability of ceramic tubular membrane technology as an alternative to conventional waste water treatment in the pulp and paper industry. In this context, in series batch and semi-batch membrane processes comprising microfiltration, ultrafiltration and nanofiltration, ceramic membranes were developed to reduce the chemical oxygen demand (COD) and remove residual lignin from the effluen...

  13. Comparison of Radicular Peroxide Leakage from four Commonly used Bleaching agents following Intracoronal Bleaching in Endodontically treated teeth - An In Vitro Study.

    Science.gov (United States)

    Madhu, Ks; Hegde, Swaroop; Mathew, Sylvia; Lata, DA; Bhandi, Shilpa H; N, Shruthi

    2013-08-01

    Non vital bleaching is simple, conservative procedure for esthetic correction of discolored endodontically treated teeth. The aim of this study was to determine and compare the amount of peroxide leakage from four different bleaching agents i.e superoxol, sodium perborate, combination of superoxol & sodium perborate and carbamide peroxide during intracoronal bleaching, as the safe and effective bleaching is the need of the hour. 50 extracted maxillary centrals were selected for the study. Following standardized protocol access, cleaning and shaping by step back technique and obturation was done using guttapercha and AH plus sealer. Access was sealed with Cavit G and outer root surface was coated with wax and nail varnish. The teeth were separated into crown and root and the root portion was placed in plastic tube containing distilled water for 7days.After incubation, 3mm of gutta-percha was removed below CEJ and 2mm glass ionomer cement base was placed. Grouped into five categories based on the bleaching agent placed in pulp chamber as -group1 (control)-distilled water, group 2-sodium perborate with distilled water , group 3- 30% hydrogen peroxide ,group 4-mixture of sodium perborate and 30% hydrogen peroxide and group 5-10% carbamide peroxide gel. Peroxide leakage was measured after 24hrs using ferrothiocyanate method and optical density using spectrophotometer. Statistical analysis of the data was conducted using ANOVA and multiple comparisons within the groups was done using BONFERRONI method (Post-Hoc tests). The results showed highest peroxide penetration from 30% hydrogen peroxide followed by mixture of sodium perborate with 30% hydrogen peroxide, mixture of sodium perborate with distilled water and least penetration from 10% carbamide peroxide gel. The results were statistically significant. Radicular peroxide leakage in 10% carbamide peroxide was significantly lower than the other tested bleaching agents making it a very safe alternative for intracoronal

  14. Electrochemical acidification of Kraft black liquor by electrodialysis with bipolar membrane: Ion exchange membrane fouling identification and mechanisms.

    Science.gov (United States)

    Haddad, Maryam; Mikhaylin, Sergey; Bazinet, Laurent; Savadogo, Oumarou; Paris, Jean

    2017-02-15

    Integrated forest biorefinery offers promising pathways to sustainably diversify the revenue of pulp and paper industry. In this context, lignin can be extracted from a residual stream of Kraft pulping process, called black liquor, and subsequently converted into a wide spectrum of bio-based products. Electrochemical acidification of Kraft black liquor by electrodialysis with bipolar membrane results in lignin extraction and caustic soda production. Even though the implementation of this method requires less chemicals than the chemical acidification process, fouling of the ion exchange membranes and especially bipolar membrane impairs its productivity. Membrane thickness and ash content measurements along with scanning electron microscopy (SEM), elemental analysis (EDX) and X-ray photoelectron spectrometry (XPS) analysis were performed to identify the nature and mechanisms of the membrane fouling. The results revealed that the fouling layer mostly consisted of organic components and particularly lignin. Based on our proposed fouling mechanisms, throughout the electrodialysis process the pH of the black liquor gradually decreased and as a result more proton ions were available to trigger protonation reaction of lignin phenolic groups and decrease the lignin solubility. Due to the abundance of the proton ions on the surface of the cation exchange layers of the bipolar membrane, destabilized lignin macro-molecules started to self-aggregate and formed lignin clusters on its surface. Over the time, these lignin clusters covered the entire surface of the bipolar membrane and the spaces between the membranes and, eventually, attached to the surface of the cation exchange membrane. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. The pulping of esparto grass by sodium monosulfite

    OpenAIRE

    Akchiche, Omar; Messaoud, Boureghda

    2007-01-01

    Traditionally, the esparto's limbs, in the manufacturing process of the cellulosic pulps, are delignified according to the process chlorinates alkaline which alternate the action of caustic's soda and chlorine; the reason is that these sheets cannot be free from the silica which they contain that only in strongly alkaline medium. In spite of the relative simplicity of implementation of this process, it does not remain free from grievance about it: low yield, an excessive consumption of bleach...

  16. QUALITY OF REACTION WOOD IN EucalyptusTREES TILTED BY WIND FOR PULP PRODUCTION

    Directory of Open Access Journals (Sweden)

    Walter Torezani Neto Boschetti

    2017-09-01

    Full Text Available This study aims to evaluate the quality of normal, tension and opposite wood of eucalyptus trees lengthwise, in straight and inclined stems, affected by wind action. It also aims to explain the pulping parameters resultant from the quality of the wood. The trees were grouped into four tilt ranges, ranging from 0 to 50º, and the basic density, chemical composition of the wood, and performance in kraft pulping were assessed. Normal and tension wood had similar basic densities; while for opposite wood, the density was lower, being responsible for a decrease in reaction wood density. The chemical composition of the wood was influenced by the presence of reaction wood in the stem.Tension and opposite wood showed lower levels of extractives and lignin and higher holocellulose content when compared to normal wood, with favorable wood quality for pulping. The increase in holocellulose content and the reduction of lignin and extractives content contributed positively to a more delignified pulp and reduction of the Kappa number. However, after cooking the reaction wood under the same conditions as those of normal wood, reaction wood pulping tends to have a lower screen yields. Due to differences in basic density and chemical constituents between opposite and normal wood, it is recommended not to designate the opposite wood as normal wood.

  17. Integrating the processes of a Kraft pulp and paper mill and its supply chain

    International Nuclear Information System (INIS)

    Mesfun, Sennai; Toffolo, Andrea

    2015-01-01

    Highlights: • A process integration model that establishes material stream connections among typical Nordic forest industries is developed. • Potential benefit of the operating the different industries in one site is studied using pinch analysis. • Different scenarios considered to assess impact of prioritization on how to utilize excess biomass. • Results indicate large potential for improved biomass resource utilization. - Abstract: This paper investigates the possibility of combining different forest industries (a pulp and paper mill, its supply chain, and a wood-pellet plant) into an integrated industrial site in which they share a common heat and power utility. Advanced process integration and optimization techniques are used to study the site from both material and energy viewpoints. An existing pulp and paper mill is used as the site core plant and its pulp and paper production rates are kept fixed as they are in reality, while the other material flow links among the plants are based on the current industrial situation in Sweden. Different scenarios are evaluated in order to reflect the two main objectives that can be pursued (increased electricity production or biomass resource saving) and the two technologies that can be considered for the shared CHP system (boilers and product gas fired gas turbines). The corresponding non-integrated (standalone) configurations are compared to these scenarios to quantify the potential benefits of the integration. Investment opportunity is also calculated for the considered scenarios as an indicator of the economic convenience

  18. Biomimetic Catalysts for Oxidation of Veratryl Alcohol, a Lignin Model Compound

    Directory of Open Access Journals (Sweden)

    Marcelino Maneiro

    2013-03-01

    Full Text Available Kraft pulp has to be bleached to eliminate the chromophoric structures, which cause a darkening of the pulp. In Nature, an equivalent role is assumed by ligninolytic enzymes such as lignin peroxidases, manganese peroxidases and laccases. The development of low molecular weight manganese peroxidase mimics may achieve environmentally-safe bleaching catalysts for the industry. Herein we report the synthesis and characterization of six manganese(III complexes 1–6, incorporating dianionic hexadentate Schiff base ligands (H2L1-H2L4 and different anions. Complex 4, Mn2L22(H2O2(DCA2 was crystallographically characterized. Complexes 1–4 behave as more efficient mimics of peroxidase in contrast to 5–6. We have studied the use of these complexes as catalysts for the degradation of the lignin model compound veratryl alcohol. The biomimetic catalysts were used in conjunction with chlorine-free inexpensive co-oxidants as dioxygen or hydrogen peroxide. Yields up to 30% of veratryl alcohol conversion to veratraldehyde have been achieved at room temperature in presence of air flow using 0.5% of catalyst.

  19. Patterns of coral bleaching: Modeling the adaptive bleaching hypothesis

    Science.gov (United States)

    Ware, J.R.; Fautin, D.G.; Buddemeier, R.W.

    1996-01-01

    Bleaching - the loss of symbiotic dinoflagellates (zooxanthellae) from animals normally possessing them - can be induced by a variety of stresses, of which temperature has received the most attention. Bleaching is generally considered detrimental, but Buddemeier and Fautin have proposed that bleaching is also adaptive, providing an opportunity for recombining hosts with alternative algal types to form symbioses that might be better adapted to altered circumstances. Our mathematical model of this "adaptive bleaching hypothesis" provides insight into how animal-algae symbioses might react under various circumstances. It emulates many aspects of the coral bleaching phenomenon including: corals bleaching in response to a temperature only slightly greater than their average local maximum temperature; background bleaching; bleaching events being followed by bleaching of lesser magnitude in the subsequent one to several years; higher thermal tolerance of corals subject to environmental variability compared with those living under more constant conditions; patchiness in bleaching; and bleaching at temperatures that had not previously resulted in bleaching. ?? 1996 Elsevier Science B.V. All rights reserved.

  20. Influence of enamel/dentin thickness on the toxic and esthetic effects of experimental in-office bleaching protocols.

    Science.gov (United States)

    de Oliveira Duque, C C; Soares, D G; Basso, F G; Hebling, J; de Souza Costa, C A

    2017-11-01

    This paper aims to assess the whitening effectiveness and toxicity of tooth-bleaching protocols applied to enamel/dentin disks simulating mandibular incisors (ICs) and premolars (PMs). A 10% hydrogen peroxide (H 2 O 2 ) gel was applied for 3 × 15, 1 × 15, or 1 × 5 min to enamel/dentin disks simulating mandibular ICs and PMs, and the trans-enamel and trans-dentinal diffusion products were applied to human dental pulp cells (1 h). Professional therapy (35% H 2 O 2 -3 × 15 min) was used as positive control, and non-bleached samples were used as negative control. Cell viability and morphology, oxidative stress generation, and odontoblastic marker expression were assessed. The H 2 O 2 diffusion and enamel color change (ΔE) were also analyzed. The 10% H 2 O 2 gel induced significant cell viability reduction only when applied 3 × 15 min, with the intensity of oxidative stress and down-regulation of odontoblastic markers being higher in the IC group. The other experimental bleaching protocols caused slight alterations regarding the cell parameters evaluated, with intensity being related to enamel/dentin thickness. These effects were also correlated with higher H 2 O 2 diffusion in the IC group. ΔE values similar as positive control were found for the 10% 3 × 15 and 1 × 15 protocols on IC group, after 4 and 6 sessions. Application of a 10% H 2 O 2 bleaching gel for 15 or 45 min to thin dental substrate significantly minimizes cell toxicity in comparison with highly concentrated gels associated with similar esthetic outcomes by increasing the number of bleaching sessions. Bleaching gels with 10% H 2 O 2 applied in small teeth for short periods may be an interesting alternative to obtain whitening effectiveness without causing toxicity to pulp cells, which may be able to reduce the tooth hypersensitivity claimed by patients.

  1. Fermentation and chemical treatment of pulp and paper mill sludge

    Science.gov (United States)

    Lee, Yoon Y; Wang, Wei; Kang, Li

    2014-12-02

    A method of chemically treating partially de-ashed pulp and/or paper mill sludge to obtain products of value comprising taking a sample of primary sludge from a Kraft paper mill process, partially de-ashing the primary sludge by physical means, and further treating the primary sludge to obtain the products of value, including further treating the resulting sludge and using the resulting sludge as a substrate to produce cellulase in an efficient manner using the resulting sludge as the only carbon source and mixtures of inorganic salts as the primary nitrogen source, and including further treating the resulting sludge and using the resulting sludge to produce ethanol.

  2. The influence of irradiation of gamma-rays on the pulping and paper making, (3)

    International Nuclear Information System (INIS)

    Mori, Kenji; Sasaki, Toru; Hasegawa, Kunihiko.

    1979-01-01

    Dissolving pulp (DP) containing no lignin and cold soda pulp containing much amount of lignin were used for the study of the influence of gamma irradiation. Experiments were made in the presence of air, water, methanol, acetic anhydride, acetic anhydride + methanol, dioxane, dimethyl sulfoxide and 1% NaOH solution. Irradiation was made for 100 hours at 20 - 21 deg. C; total irradiation dose was 1.47 x 10 7 R. (1) In case of dimethyl sulfoxide, and especially in case of 1% NaOH solution, the yield decreased by irradiation, with cold soda pulp particularly. (2) In case of the pulp immersed in water, the brightness of pulp was not improved by irradiation, but in methanol, it was remarkably improved. Since the improvement was observed in both DP and cold soda pulps, it is caused by the action of oxidizing bleach with small amount of oxygen in the air remaining in the material, instead of the change in the quality of lignin. (3) By infrared analysis, methanol did not react with the lignin in cold soda pulp even under irradiation. (4) The acetylation was accelerated by irradiation. (J.P.N.)

  3. Electron beam processing technology for modification of different types of cellulose pulps for production of derivatives

    International Nuclear Information System (INIS)

    Iller, E.; Kukielka, A.; Mikolajczyk, W.; Starostka, P.; Stupinska, H.

    2002-01-01

    Institute of Nuclear Chemistry and Technology, Pulp and Paper Research Institute and Institute of Chemical Fibers carry out a joint research project in order to develop the radiation methods modification of cellulose pulps for production of cellulose derivatives such as carbamate (CC), carboxymethyl cellulose (CMC) and methylcellulose (MC). Three different types of textile pulps: Alicell (A); Borregaard (B), Ketchikan (K) and Kraft softwood (PSS) and hardwood (PSB) pulps have been irradiated with 10 MeV electron beam from LAE 13/9 linear accelerator with doses of 5, 10, 15, 20, 25 and 50 kGy. After electron beam treatment the samples of cellulose pulps have been examined by using of structural and physico-chemical methods. Electron paramagnetic resonance spectroscopy (EPR), gel permeation chromatography (GPC) and infrared spectroscopy (IRS) were applied for determination of structural changes in irradiated cellulose pulps. By means of analytical methods, such parameters as: viscosity, average degree of polymerization (DP) and α-cellulose contents were evaluated. Based on EPR and GPC investigations the relationship between concentrations of free radicals and decreasing polymerization degrees in electron beam treatment pulps has been confirmed. The carboxymethylcellulose, methylcellulose and cellulose carbamate were prepared using the raw material of radiation modified pulps. Positive results of investigations will allow for determination of optimum conditions for electron beam modification of selected cellulose paper and textile pulps. Such procedure leads to limit the amounts of chemical activators used in methods for preparation cellulose derivatives. The proposed electron beam technology is new approaches in technical solution and economic of process of cellulose derivatives preparation. (author)

  4. Sacrificial adsorbate for surfactants utilized in chemical floods of enhanced oil recovery operations

    Science.gov (United States)

    Johnson, Jr., James S.; Westmoreland, Clyde G.

    1982-01-01

    The present invention is directed to a sacrificial or competitive adsorbate for surfactants contained in chemical flooding emulsions for enhanced oil recovery operations. The adsorbate to be utilized in the method of the present invention is a caustic effluent from the bleach stage or the weak black liquor from the digesters and pulp washers of the kraft pulping process. This effluent or weak black liquor is injected into an oil-bearing subterranean earth formation prior to or concurrent with the chemical flood emulsion and is adsorbed on the active mineral surfaces of the formation matrix so as to effectively reduce adsorption of surfactant in the chemical flood. Alternatively, the effluent or liquor can be injected into the subterranean earth formation subsequent to a chemical flood to displace the surfactant from the mineral surfaces for the recovery thereof.

  5. STORAGE OF CHEMICALLY PRETREATED WHEAT STRAW – A MEANS TO ENSURE QUALITY RAW MATERIAL FOR PULP PREPARATION

    Directory of Open Access Journals (Sweden)

    Terttu Heikkilä

    2010-07-01

    Full Text Available The aim of this study was to evaluate effects of chemical pretreatment and storage on non-wood pulping and on pulp quality. The processes studied were hot water treatment followed by alkaline peroxide bleaching or soda cooking. The results showed that it is possible to store wheat straw outside for at least one year without significant changes in the raw material chemical composition and without adverse effects on the resulting pulp quality. The results are significant to the industry using non-woods to ensure the availability and the quality of the raw-material throughout the year in spite of the short harvesting time.

  6. Electronomicroscopic evaluation of the microlesional aspects in the pulp dentinal complex after repeated whitening therapy

    Science.gov (United States)

    Bodea, Rodica; Jianu, Rodica; Marchese, Cristian; Vasile, Liliana

    2012-06-01

    The aim of this study was to examine cellular and matriceal dynamics within pulp tissue of the teeth with repeated bleaching. Material and method - The study was made on 25 patients aged between 15 and 45, to whom bleaching method of the premolars with indication of extraction in orthodontic purposes was applied. None of the subjects smoked and throughout the investigation no antibiotics had been used. We initiated an intensive oral hygiene program, and we removed the supragingival and subgingival deposits. Oral hygiene and the gingival health were evaluated before every session of bleaching. During each visit the dentition was cleaned professionally and if needed the subjects were reinstucted in proper oral hygiene. After 3 and 5 successive bleachings of the teeth, we removed the dental pulps and we extracted the premolars. The pulpal biopsies were fixed in buffed formaldehyde 10% for 48 hours, then paraffinized, sectioned at 3-5 μ and stained with topographic, H&E and trichrome stained. For the electonomicroscopic study we used the Lehner technique to process the biopsies (n=3) after the reinclusion of the pieces from the paraffine blocks in Epon, postfixated in buffered glutaraldehyde, micro sectioned at 0,5 μ, contrastated with Pb citrate (stained) and examination in transmission electronic microscopy with Philips microscope. Results - At cellular and matriceal level we observed a marked collagen fibrillogenesis in the presence of active fibroblasts, with well developed cellular organites and fibroclastic aspects which suggest matriceal active repair. The microvascular network presents an activated endothelium with turgescent endothelial cells, with intracitoplasmatic resorbtion vacuols, well developed Golgi Complex. Conclusion - We interpreed the cell - matriceal lesions in the context of the acute inflammatory process in the first lesional phase and chronic scleroatrophic process after successive bleaching.

  7. Endoglucanase post-milling treatment for producing cellulose nanofibers from bleached eucalyptus fibers by a supermasscolloider

    Science.gov (United States)

    Wangxia Wang; Michael D. Mozuch; Ronald C. Sabo; Philip Kersten; Junyong Zhu; Yongcan Jin

    2016-01-01

    Three recombinant GH5 endoglucanases chosen for their contrasting hydrolytic activities, and a commercial endoglucanase were used to treat cellulose nanofibers (CNFs) after they were milled from bleached eucalyptus pulp with a supermasscolloider. This enzyme ‘‘post-treatment’’ resulted in different properties for the CNFs depending on enzyme treatment. The degree of...

  8. Kraft cooking of gamma irradiated wood, (1)

    International Nuclear Information System (INIS)

    Inaba, Masamitsu; Meshitsuka, Gyosuke; Nakano, Junzo

    1979-01-01

    Studies have been made of kraft cooking of gamma irradiated wood. Beech (Fagus crenata Blume) wood meal suspended in aqueous alkaline alcohol was irradiated up to 1.5 KGy (0.15 Mrad) with gamma rays from a Co-60 source in the presence or absence of oxygen. The irradiated wood meals were washed thoroughly with fresh water, air dried and cooked under the ordinary cooking conditions. The results are summarized as follows: (1) Pre-irradiation in aqueous alkali have negligible effect on kraft cooking. (2) In the case of ethanol addition (50 g/l), pre-irradiation in vacuo shows acceleration of delignification and stabilization of carbohydrates during kraft cooking. Cooked yield gain by pre-irradiation was about 1.2% in all over the range of delignification from 80 to 90%. Aqueous ethanol without alkali also shows positive but smaller effect than that with alkali. (3) Propanol, iso-propanol and butanol show positive but smaller effects than ethanol. However, methanol does not show any positive effect. (4) Irradiation in the presence of oxygen does not show any attractive effect on kraft cooking. (author)

  9. Experimental investigation of different refining stages influences on optical and ultrasonic signals in paper pulp suspensions

    International Nuclear Information System (INIS)

    Jan, Niemi

    2010-01-01

    An important parameter to control in papermaking is the fiber mass fraction in the pulp suspension. Poor control to an unstable process that compromises the production, quality and the energy efficiency in the pulp mill. Using optical or ultrasound measurement techniques can obtain estimation of the mass fraction. Refining is an important operation in preparing the fibers for the paper machine. Refining influence the properties of the fiber by crushing the fiber, roughens the fiber surface and occasionally cut fibers and removes parts of the outer fiber wall leading to an increasing amount of short fibers (fines). A freeness tester was used for verify the changes in fiber properties at four different refining levels. The result shows that for unbleached softwood pulp the used measurement techniques either were not observable or minor. The results indicate that refining can potentially influence accurate consistency estimation for unbleached softwood pulp but for bleached hardwood pulp the influence is believed to be minor using the investigating measurement techniques

  10. Review on Bamboo Utilization as Biocomposites, Pulp and Bioenergy

    Science.gov (United States)

    Yusuf, Sulaeman; Syamani, F. A.; Fatriasari, W.; Subyakto

    2018-03-01

    One of potential non wood bioresources utilized in industrial application is bamboos. Bamboos are include in graminae family which have high biomass productivity, easy and rapid production, wide avability and high holocellulose content. Indonesia has a huge potential of bamboos, more than 162 bamboo species are found however only some of them are planted that have a high economic value. Bamboos have some advantages such as can be harvested at 3 years, straight culm, high strength, easy to be processed, and relatively cheap. Research Center for Biomaterials has developed utilization of bamboo culm for ply bamboo product as alternative of plywood since 1995, using gombong bamboo, tali bamboo, sembilang bamboo, andong bamboo with PF resin as adhesive. Other biocomposite products from bamboos include particle board, cement board and polymer-bamboo fiber composites. In term of processing technique and final product quality, bamboo composites from ply bamboo are the most prospectable material to be utilized in industrial application. Yellow bamboo and betung bamboo have also been developed as pulp and paper. Biopulping using soda and kraft pulping after biological pretreatment using white rot fungi to remove lignin was used as pulping method in this conversion. Biokraft pulping with Trametes versicolor for 45 days with inoculum loading of 10% resulted better pulp quality compared to the other fungi. Betung bamboo had good morphological characteristics and chemical component content to be converted into bioenergy such as bioethanol. Several pretreatment methods have been developed in order to result high sugar yield. Microwave assisted acid hydrolysis was preferedin producing higher yield from the pretreated bamboo compared to enzymatic hydrolysis. By using this method, the bamboo pretreated by biological-microwave pretreatment results higher improvement to increase sugar yield.

  11. Assessing the application of advanced oxidation processes, and their combination with biological treatment, to effluents from pulp and paper industry.

    Science.gov (United States)

    Merayo, Noemí; Hermosilla, Daphne; Blanco, Laura; Cortijo, Luis; Blanco, Angeles

    2013-11-15

    The closure of water circuits within pulp and paper mills has resulted in a higher contamination load of the final mill effluent, which must consequently be further treated in many cases to meet the standards imposed by the legislation in force. Different treatment strategies based on advanced oxidation processes (ozonation and TiO2-photocatalysis), and their combination with biological treatment (MBR), are herein assessed for effluents of a recycled paper mill and a kraft pulp mill. Ozone treatment achieved the highest efficiency of all. The consumption of 2.4 g O3 L(-1) resulted in about a 60% COD reduction treating the effluent from the kraft pulp mill at an initial pH=7; although it only reached about a 35% COD removal for the effluent of the recycled paper mill. Otherwise, photocatalysis achieved about a 20-30% reduction of the COD for both type of effluents. In addition, the effluent from the recycled paper mill showed a higher biodegradability, so combinations of these AOPs with biological treatment were tested. As a result, photocatalysis did not report any significant COD reduction improvement whether being performed as pre- or post-treatment of the biological process; whereas the use of ozonation as post-biological treatment enhanced COD removal a further 10%, summing up a total 90% reduction of the COD for the combined treatment, as well as it also supposed an increase of the presence of volatile fatty acids, which might ultimately enable the resultant wastewater to be recirculated back to further biological treatment. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Effects of different activation processes on H2O2/TAED bleaching of Populus nigra chemi-thermo mechanical pulp

    OpenAIRE

    Qiang Zhao; Dezhi Sun; Zhaohong Wang; Junwen Pu; Xiaojuan Jin; Mian Xing

    2012-01-01

    Tetra acetyl ethylene diamine (TAED) was used as an activator in H2O2 bleaching to improve bleaching efficiency. The present work was aimed at confirming different activations for various H2O2/TAED bleaching processes, including the addition of acetic anhydride and the step-addition of sodium hydroxide. The results showed that an acetic anhydride dosage of 1%, an acetic anhydride treatment time of 10 min, and an addition time of 45 min were the optimal treatment conditions. The optimum proces...

  13. Kraft Lignin Depolymerization in an Ionic Liquid without a Catalyst

    Directory of Open Access Journals (Sweden)

    Amadou Diop

    2015-06-01

    Full Text Available In this paper, the depolymerization of lignin was successfully achieved by the thermal treatment of kraft lignin in butyl-1,8-diazabicyclo[5.4.0]undec-7-enium chloride ([DBUC4+][Cl-] without a catalyst. The thermal treatment experiments were performed in an oven at 150, 200, and 250 °C for 1 h. The changes in kraft lignin structure over the course of depolymerization were characterized by gel permeation chromatography (GPC, Fourier transform infrared (FTIR spectroscopy, and 1H / 31P NMR analyses. GPC chromatograms indicated that the retention time of the original kraft lignin had shifted toward higher values after the thermal treatment, which indicated lignin depolymerization. The average molecular weight of the lignin obtained after 1 h reaction time decreased by 23, 70, and 58 wt% for the treatment at 150, 200, and 250 °C, respectively. FTIR spectra indicated the cleavage of β-O-4 bonds of kraft lignin. The 1H NMR spectra showed demethylation of all treated kraft lignins. Moreover, the 31P NMR analysis demonstrated that the demethylation phenomenon of the treated kraft lignin contributed to the formation of catechol groups.

  14. Laser Teeth Bleaching: Evaluation of Eventual Side Effects on Enamel and the Pulp and the Efficiency In Vitro and In Vivo

    Science.gov (United States)

    De Moor, Roeland Jozef Gentil; Meire, Maarten August; De Coster, Peter Jozef

    2015-01-01

    Light and heat increase the reactivity of hydrogen peroxide. There is no evidence that light activation (power bleaching with high-intensity light) results in a more effective bleaching with a longer lasting effect with high concentrated hydrogen peroxide bleaching gels. Laser light differs from conventional light as it requires a laser-target interaction. The interaction takes place in the first instance in the bleaching gel. The second interaction has to be induced in the tooth, more specifically in the dentine. There is evidence that interaction exists with the bleaching gel: photothermal, photocatalytical, and photochemical interactions are described. The reactivity of the gel is increased by adding photocatalyst of photosensitizers. Direct and effective photobleaching, that is, a direct interaction with the colour molecules in the dentine, however, is only possible with the argon (488 and 415 nm) and KTP laser (532 nm). A number of risks have been described such as heat generation. Nd:YAG and especially high power diode lasers present a risk with intrapulpal temperature elevation up to 22°C. Hypersensitivity is regularly encountered, being it of temporary occurrence except for a number of diode wavelengths and the Nd:YAG. The tooth surface remains intact after laser bleaching. At present, KTP laser is the most efficient dental bleaching wavelength. PMID:25874258

  15. Energy conservation in the pulp and paper industry. Final report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1977-05-01

    Almost 40 specific research and development ideas were formulated by the 67 participants at this workshop. Projects were assessed with the following criteria in mind: potential energy savings, cost, risk, Federal role, time frame, and priority. Data are tabulated on the projects followed by six topics discussed by panel members: waste and recycling, energy management in the mill, papermaking, pulping and bleaching, power generation in the mill, and coating and conversion. Three summary speeches are included. (MCW)

  16. Biodegradation behaviors and color change of composites based on type of bagasse pulp/polylactic acid

    Directory of Open Access Journals (Sweden)

    maryam allahdadi

    2017-05-01

    Full Text Available In this research, appearance quality and decay resistance of polylactic acid (PLA based green composites made from monoethanolamine (MEA bagasse pulp, alkaline sulfite-anthraquinone (AS bagasse pulp, bleached soda (B S bagasse pulp, unbleached soda (UN S bagasse pulp (UN S bagasse pulp and raw bagasse fibers (B were investigated. For the investigation of biodegradation behaviors, effect of the white rot fungi (Coriolus versicolor on the neat PLA and composites with natural fibers during 30 and 60 days were studied. It is found that when the bagasse fibers were incorporated into composites matrix, percentage weight reduction and stiffness of samples have been increased. Also, the rate of loss mentioned of the composites made from bagasse pulp fibers were superior to the relevant raw bagase fibers. This can be explained by the removal of non-cellulosic components such as lignin and hemicelluloses from the fibers by pulping process. Also, the results indicates the inferior of surface qualities of fabricated composites regarding to neat PLA. Depending on the fiber type, different reductions of the surface qualities were attained. However, the degree of color change of the composites with any type of bagasse pulp fibers were lower compared with composite with raw bagasse fiber. Finally, as compared with the raw bagasse fibers, bagasse pulp fibers have better reinforcing capability.

  17. Use of high-boiling point organic solvents for pulping oil palm empty fruit bunches.

    Science.gov (United States)

    Rodríguez, Alejandro; Serrano, Luis; Moral, Ana; Pérez, Antonio; Jiménez, Luis

    2008-04-01

    Oil palm empty fruit bunches were used as an alternative raw material to obtain cellulosic pulp. Pulping was done by using high-boiling point organic solvents of decreased polluting power relative to classical (Kraft, sulphite) solvents but affording operation at similar pressure levels. The holocellulose, alpha-cellulose and lignin contents of oil palm empty fruit bunches (viz. 66.97%, 47.91% and 24.45%, respectively) are similar to those of some woody raw materials such as pine and eucalyptus, and various non-wood materials including olive tree prunings, wheat straw and sunflower stalks. Pulping tests were conducted by using ethyleneglycol, diethyleneglycol, ethanolamine and diethanolamine under two different sets of operating conditions, namely: (a) a 70% solvent concentration, 170 degrees C and 90 min; and (b) 80% solvent, 180 degrees C and 150 min. The solid/liquid ratio was six in both cases. The amine solvents were found to provide pulp with better properties than did the glycol solvents. Ethanolamine pulp exhibited the best viscosity and drainage index (viz. 636 mL/g and 17 degrees SR, respectively), and paper made from it the best breaking length (1709 m), stretch (1.95%), burst index (0.98 kN/g) and tear index (0.33 mNm(2)/g). Operating costs can be reduced by using milder conditions, which provide similar results. In any case, the amines are to be preferred to the glycols as solvents for this purpose.

  18. Effect of Soda-Anthraquinone Pulping Conditions and Beating Revolution on the Mechanical Properties of Paper made from Gigantochloa scortechinii (Semantan Bamboo)

    International Nuclear Information System (INIS)

    Nurul Husna Mohd Hassan; Suhaimi Muhammed

    2013-01-01

    The effect of soda-AQ pulping conditions and beating revolution on the mechanical properties of paper made from Semantan bamboo (Gigantochloa scortechinii) was studied. The bamboo chips were pulped using MK digester pulping unit with 10 to 20 % alkali charge and 150 to 170 degree Celsius cooking temperature. The screened yield varies from 38.7 to 48.4 %, and each yield went through beating process at 1000 or 8000 beating revolutions. The bamboo pulp was then made into 60 g/ m 2 laboratory scale papers and their mechanical properties were assessed conforming to TAPPI standards. The results revealed that tensile index, bursting index, tearing index and folding endurance ranged from 42.04 to 91.09 Nm/ g, 2.68 to 7.10 kPa.m 2 /g, 11.03 to 26.64 mN.m 2 /g and 30 to 1127 double folds, respectively. The highest paper properties were found from pulping condition of 15 % alkali charge and 150 degree Celsius cooking temperature based on the fibre bonding index, with tensile index at 87.71 Nm/g, bursting index at 6.94 kPa.m 2 / g, tearing index at 12.72 mN.m 2 / g and folding endurance at 613 double folds. Such findings indicate that comparable high strength mechanical properties of paper can be produced from Semantan bamboo pulp with more environmentally friendly pulping process compared to the kraft pulping process that had been used in bamboo pulping. (author)

  19. Treatment of real industrial wastewaters through nano-TiO2 and nano-Fe2O3 photocatalysis: case study of mining and kraft pulp mill effluents.

    Science.gov (United States)

    Nogueira, V; Lopes, I; Rocha-Santos, T A P; Gonçalves, F; Pereira, R

    2018-06-01

    High quantities of industrial wastewaters containing a wide range of organic and inorganic pollutants are being directly discharged into the environment, sometimes without proper treatment. Nanotechnology has a tremendous potential improving the existing treatments or even develop new treatment solutions. In this study, nano-TiO 2 or nano-Fe 2 O 3 was used for the photocatalytic treatment of kraft pulp mill effluent and mining effluent. The experiments with the organic effluent lead to reduction percentages of 93.3%, 68.4% and 89.8%, for colour, aromatic compounds and chemical oxygen demand, respectively, when treated with nano-TiO 2 /H 2 O 2 /UV and nano-Fe 2 O 3 /H 2 O 2 /UV, at pH 3.0. Significant removal of metals from the mining effluent was recorded but only for Zn, Al and Cd, the highest removal attained with 1.0 g L -1 of nano-TiO 2 /UV and nano-Fe 2 O 3 /UV. Regarding the toxicity of the organic effluent to Vibrio fischeri, it was reduced with the treatments combining the oxidant and the catalyst. However, for the inorganic effluent, the best reduction was achieved using 1.0 g L -1 of catalyst. In fact, the increase in dose of the catalyst, especially for nano-TiO 2 , enhanced toxicity reduction. Our results have shown that the use of these NMs seemed to be more effective in the organic effluent than in metal-rich effluent.

  20. Fracture resistance of teeth submitted to several internal bleaching protocols.

    Science.gov (United States)

    Leonardo, Renato de Toledo; Kuga, Milton Carlos; Guiotti, Flávia Angélica; Andolfatto, Carolina; Faria-Júnior, Norberto Batista de; Campos, Edson Alves de; Keine, Kátia Cristina; Dantas, Andrea Abi Rached

    2014-03-01

    The aim of this study was to evaluate the fracture resistance of teeth submitted to several internal bleaching protocols using 35% hydrogen peroxide (35HP), 37% carbamide peroxide (37CP), 15% hydrogen peroxide with titanium dioxide nanoparticles (15HPTiO2) photoactivated by LED-laser or sodium perborate (SP). After endodontic treatment, fifty bovine extracted teeth were divided into five groups (n = 10): G1-unbleached; G2-35HP; G3-37CP; G4-15HPTiO2 photoactivated by LED-laser and G5-SP. In the G2 and G4, the bleaching protocol was applied in 4 sessions, with 7 days intervals between each session. In the G3 and G5, the materials were kept in the pulp teeth for 21 days, but replaced every 7 days. After 21 days, the teeth were subjected to compressive load at a cross head speed of 0.5 mm/min, applied at 135° to the long axis of the root using an eletromechanical testing machine, until teeth fracture. The data were submitted to ANOVA and Tukey tests (α = 5%). The 35HP, 37CP, 15HPTiO2 and SP showed similar fracture resistance teeth reduction (p > 0.05). All bleaching treatments reduced the fracture resistance compared to unbleached teeth (p endodontically-treated teeth, but there were no differences between each other. There are several internal bleaching protocols using hydrogen peroxide in different concentrations and activation methods. This study evaluated its effects on fracture resistance in endodontically-treated teeth.

  1. The Green Integrated Forest Biorefinery: An innovative concept for the pulp and paper mills

    International Nuclear Information System (INIS)

    Rafione, Tatiana; Marinova, Mariya; Montastruc, Ludovic; Paris, Jean

    2014-01-01

    The Green Integrated Forest Biorefinery (GIFBR), a new concept suitable for implementation in pulp and paper mills is characterized by low greenhouse gases emissions, reduced water consumption and production of effluents. Its fossil fuel consumption must be nil. Several challenges have to be addressed to develop a sustainable GIFBR facility. An implementation strategy by phase is proposed to schedule the total capital investment over several years and to mitigate the economic risks associated with the transformation of an existing pulp and paper mill into a GIFBR. In the first phase of the methodology, the receptor mill and the biorefinery plant are selected. An intensive energy and material integration of the two plants is performed in the second phase, then a gasification unit is implemented and, finally a polygeneration unit is installed. The methodology is illustrated by application to a case study based on a reference Canadian Kraft mill. Each phase of the implementation strategy of the GIFBR is described. - Highlights: • The Green Integrated Forest Biorefinery (GIFBR) is a new biorefinery concept. • A GIFBR includes a pulp mill, a biorefinery, a gasification and a polygeneration units. • An implementation strategy by phase is proposed to successfully develop a GIFBR. • To determine achievable level of integration between the GIFBR constituents is crucial. • GIFBR concept technically and economically feasibility for pulp and paper mills

  2. Innovations in papermaking: An LCA of printing and writing paper from conventional and high yield pulp

    International Nuclear Information System (INIS)

    Manda, B.M. Krishna; Blok, Kornelis; Patel, Martin K.

    2012-01-01

    Pulp and paper industry is facing challenges such as resource scarcity and greenhouse gas (GHG) emissions. The objective of this research is to investigate whether the use of new coatings (micro or nano TiO 2 ) and different pulp types could bring savings in wood, energy, GHG emissions and other environmental impacts in comparison with conventional printing and writing paper. We studied three types of pulp, namely i) unbleached virgin kraft pulp, ii) recovered fiber, and iii) high yield virgin chemithermo-mechanical pulp (CTMP). A life cycle assessment (LCA) was conducted from cradle to grave. Applying attributional modeling, we found that wood savings amount to 60% for the nanoparticle coated recovered fiber paper and 35% for the micro TiO 2 coated CTMP paper. According to the ReCiPe single score impact assessment method, the new product configurations allow the reduction of the environmental impacts by 10–35% compared to conventional kraft paper. Applying consequential modeling, we found larger energy and GHG emission savings compared to attributional modeling because the saved wood is used for producing energy, thereby replacing fossil fuels. The nanoparticle coated recovered fiber paper offered savings of non-renewable energy use (NREU) by 100% (13 GJ/ton paper) and GHG emission reduction by 75% (0.6 ton CO 2 eq./ton paper). Micro TiO 2 coated CTMP paper offered NREU savings by 25% (3 GJ/ton paper) and savings of GHG emissions by 10% (0.1 ton CO 2 eq./ton paper). The taking into account of all environmental impacts with the ReCiPe single score method leads to comparable results as that of attributional modeling. We conclude that the nanoparticle coated recovered fiber paper offered the highest savings and lowest environmental impacts. However, human toxicity and ecotoxicity impacts of the nanoparticles were not included in this analysis and need further research. If this leads to the conclusion that the toxicity impacts of the nanoparticles are serious, then

  3. Pulp-mill related polychlorinated organic compounds in Baltic Sea sediments

    Energy Technology Data Exchange (ETDEWEB)

    Jonsson, Per (Swedish Environmental Protection Agency, Solna (Sweden)); Rappe, C.; Kjeller, L.O. (Umeaa Univ. (Sweden). Inst. of Environmental Chemistry); Kierkegaard, A. (Stockholm Univ. (Sweden). Inst. of Applied Environmental Research); Haakansson, L. (Uppsala Univ. (Sweden). Inst. of Earth Sciences); Jonsson, Bjoern (County Adm. Board, Umeaa (Sweden))

    1993-01-01

    Sediment samples from the Baltic basin were analyzed for PCDD/Fs, alkyl-CDFs, chloroguaiacols and EOCl. The EOCl distribution pattern in the Iggesund pulp-mill area shows high sediment concentrations close to the mill, and decreasing concentrations with increasing distance from the mill. Two series of alkyl-CDFs have been identified. The PCDD/Fs in offshore surficial sediments from the Baltic proper show a typical incineration pattern, while sediments collected in the vicinity of the mill show enhanced levels of 2,3,7,8-tetraCDD, 2,3,7,8- and 1,2,7,8-tetraCDF, and 1,2,3,7,8-pentaCDD. These PCDD/F congeners are statistically correlated to di-, tri-, and tetrachloroguaiacols, alkyl-CDFs, EOCl, and to the distance from the pulp mill, indicating the same source and transportation regime. Principal component analysis of the data set supports this conclusion. The three 2,3,7,8-tetrachloro-substituted PCDD/F congeners have formerly been found in high concentrations in sediments and crab hepatopancreas close to a pulp mill on the Swedish west coast. Our results from a pulp mill on the Swedish east coast support the conclusion that these congeners are typically associated with pulp bleaching. Deep layer sediments have significantly lower levels of PCDD/Fs. The isomer profiles are different in the surficial and the deep sediments, indicating a more natural preindustrial production of PCDD/Fs. (53 refs., 7 figs.).

  4. Effects of Kraft Mill effluent on the sexuality of fishes: An environmental early warning

    Energy Technology Data Exchange (ETDEWEB)

    Davis, W.P.; Bortone, S.A.

    1992-01-01

    Arrhenoid or masculinized female fish species of the live-bearing family, Poeciliidae, have been observed for over thirteen years in specific southern streams which receive waste effluents from pulping mills. The complex mixture of organic compounds in kraft mill effluent (KME) has inhibited specific identification of causal agent(s). However, microbially degraded phytosterols (e.g. sitosterol or stigmastanol) in experimental exposures induce the same intersexual states that characterize affected female poeciliids sampled from KME streams. KME-polluted streams often exhibit a drastic reduction of fish species diversity and degrees of physiological stress, all of which suggests reduced reproduction in surviving forms. A potential ontogenetic or developmental response is demonstrated in American eels captured in one of these streams as well. The authors examine available information, including laboratory and experimental field exposures, and suggest directions for additional research as well as the need for environmental concern.

  5. Caracterização de compostos reduzidos de enxofre gerados na produção de celulose kraft e pré-hidrólise kraft.

    Directory of Open Access Journals (Sweden)

    Afonso Moraes de Moura

    2010-08-01

    Full Text Available Um problema ambiental da indústria de celulose kraft é o odor causado pela emissão dos compostos reduzidos de enxofre gerados pela deslignificação de madeiras de um modo em geral. Para monitorar essas emissões, existem equipamentos simples, desenvolvidos para a medição contínua do "total reduced sulphur" (TRS, tal como o analisador coulométrico. Neste trabalho, foram analisados sulfeto de hidrogênio (H2S, metil mercaptana (CH3SH, dimetil sulfeto [(CH32S] e dimetil dissulfeto [(CH32S2], gerados em deslignificações laboratoriais kraft e pré-hidrólise kraft de dois grupos de madeiras de folhosas. Um dos grupos de madeiras continha 25% e o outro 20% de lignina, base peso seco. Foi observado que as madeiras com menores teores de lignina geraram significativamente menores quantidades de compostos reduzidos de enxofre de TRS. Não foram notadas diferenças significativas nas quantidades totais geradas entre os processos de deslignificação estudados. O processo pré-hidrólise kraft foi mais sensível aos teores de lignina da madeira que o processo kraft. Recomenda-se, por isso, trabalhar com madeiras com menores teores de lignina quando do uso do processo pré-hidrólise kraft para produção de celulose. As principais formas geradas de TRS foram dimetil sulfeto e metil mercaptana.

  6. The effect of oxyalkylation and application of polymer dispersions on the thermoformability and extensibility of paper.

    Science.gov (United States)

    Kouko, Jarmo; Setälä, Harri; Tanaka, Atsushi; Khakalo, Alexey; Ropponen, Jarmo; Retulainen, Elias

    2018-04-15

    Wood fiber-based packaging materials, as renewable materials, have growing market potential due to their sustainability. A new breakthrough in cellulose-based packaging requires some improvement in the mechanical properties of paper. Bleached softwood kraft pulp was mechanically treated, in two stages, using high- and low-consistency refining, sequentially. Chemical treatment of pulp using the oxyalkylation method was applied to modify a portion of fiber material, especially the fiber surface, and its compatibility with polymer dispersions including one carbohydrate polymer. The results showed that the compatibility of the cellulosic fibers with some polymers could be improved with oxyalkylation. By adjusting mechanical and chemical treatments, and the thermoforming conditions, the formability of paper was improved, but simultaneously the strength and stiffness decreased. The results suggest that the formability of the paper is not a direct function of the extensibility of the applied polymer, but also depends on the fiber network structure and surface energy. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. Ole Bjørn Kraft 1893-1980

    DEFF Research Database (Denmark)

    Skov, Christian Houlberg

    2010-01-01

    Ole Bjørn Kraft (1893-1980) var en central konservativ politiker i årene før og efter anden verdenskrig. Han markerede sig som udpræget idépolitiker og opnåede ad flere omgange at blive minister.......Ole Bjørn Kraft (1893-1980) var en central konservativ politiker i årene før og efter anden verdenskrig. Han markerede sig som udpræget idépolitiker og opnåede ad flere omgange at blive minister....

  8. Selective enrichment of a methanol-utilizing consortium using pulp & paper mill waste streams

    Energy Technology Data Exchange (ETDEWEB)

    Gregory R. Mockos; William A. Smith; Frank J. Loge; David N. Thompson

    2007-04-01

    Efficient utilization of carbon inputs is critical to the economic viability of the current forest products sector. Input carbon losses occur in various locations within a pulp mill, including losses as volatile organics and wastewater . Opportunities exist to capture this carbon in the form of value-added products such as biodegradable polymers. Waste activated sludge from a pulp mill wastewater facility was enriched for 80 days for a methanol-utilizing consortium with the goal of using this consortium to produce biopolymers from methanol-rich pulp mill waste streams. Five enrichment conditions were utilized: three high-methanol streams from the kraft mill foul condensate system, one methanol-amended stream from the mill wastewater plant, and one methanol-only enrichment. Enrichment reactors were operated aerobically in sequencing batch mode at neutral pH and 25°C with a hydraulic residence time and a solids retention time of four days. Non-enriched waste activated sludge did not consume methanol or reduce chemical oxygen demand. With enrichment, however, the chemical oxygen demand reduction over 24 hour feed/decant cycles ranged from 79 to 89 %, and methanol concentrations dropped below method detection limits. Neither the non-enriched waste activated sludge nor any of the enrichment cultures accumulated polyhydroxyalkanoates (PHAs) under conditions of nitrogen sufficiency. Similarly, the non-enriched waste activated sludge did not accumulate PHAs under nitrogen limited conditions. By contrast, enriched cultures accumulated PHAs to nearly 14% on a dry weight basis under nitrogen limited conditions. This indicates that selectively-enriched pulp mill waste activated sludge can serve as an inoculum for PHA production from methanol-rich pulp mill effluents.

  9. EFFECTIVITY OF TWO BLEACHING AGENT OF 10% CARBAMIDE PEROXIDE WITH AND WITHOUT POTASSIUM NITRATE-FLUORIDE (CLINICAL STUDY

    Directory of Open Access Journals (Sweden)

    Ayus Lusiyanti

    2015-06-01

    Full Text Available Tooth bleaching has become a popular treatment for esthetic improvement in dentistry. There are several 10% carbamide peroxide bleaching agents that are available in Indonesia which contained potassium nitrate-fluoride or without potassium nitrate-fluoride. However, there was no clinical report about these products in Indonesia. This study was conducted to compare the effectiveness of two bleaching and sensitivity of tooth and gingiva. Sixty-four participants were divided into 2 groups. The first group was treated with bleaching agent that contained potassium nitrate-fluoride (Opalescence PF, Ultradent. Bleaching treatment was done for 6-8 hours per night over a 2 week-period. Evaluations were performed at the baseline and at 3, 7, 14 day afterwards. Color change was measured using a value-ordered Vita classic shade guide; tooth and gingival sensitivity were examine using Electric Pulp Tester, Gingival Index and patient log. The results showed that there were no statistical differences in degree of color change between the two products. The mean color change after 2 weeks was 7-8 tabs lighter than baseline. Also there was no statistical difference in tooth and gingival sensitivity between the products. It can be concluded that 10% carbamide peroxide containing potassium nitrate-fluoride has the same effectiveness compared to other agent without potassium nitrate-fluoride for tooth color change and tooth and gingival sensitivity.

  10. Evaluation of lignins from side-streams generated in an olive tree pruning-based biorefinery: Bioethanol production and alkaline pulping.

    Science.gov (United States)

    Santos, José I; Fillat, Úrsula; Martín-Sampedro, Raquel; Eugenio, María E; Negro, María J; Ballesteros, Ignacio; Rodríguez, Alejandro; Ibarra, David

    2017-12-01

    In modern lignocellulosic-based biorefineries, carbohydrates can be transformed into biofuels and pulp and paper, whereas lignin is burned to obtain energy. However, a part of lignin could be converted into value-added products including bio-based aromatic chemicals, as well as building blocks for materials. Then, a good knowledge of lignin is necessary to define its valorisation procedure. This study characterized different lignins from side-streams produced from olive tree pruning bioethanol production (lignins collected from steam explosion pretreatment with water or phosphoric acid as catalysts, followed by simultaneous saccharification and fermentation process) and alkaline pulping (lignins recovered from kraft and soda-AQ black liquors). Together with the chemical composition, the structure of lignins was investigated by FTIR, 13 C NMR, and 2D NMR. Bioethanol lignins had clearly distinct characteristics compared to pulping lignins; a certain number of side-chain linkages (mostly alkyl-aryl ether and resinol) accompanied with lower phenolic hydroxyls content. Bioethanol lignins also showed a significant amount of carbohydrates, mainly glucose and protein impurities. By contrast, pulping lignins revealed xylose together with a dramatical reduction of side-chains (some resinol linkages survive) and thereby higher phenol content, indicating rather severe lignin degradation during alkaline pulping processes. All lignins showed a predominance of syringyl units. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Corrosion Study of Stainless Steels in Peracetic Acid Bleach Media With and Without Chloride and Chelant

    Directory of Open Access Journals (Sweden)

    Rohtash

    2014-12-01

    Full Text Available The paper industries are adopting non-chlorine containing chemicals e.g. peroxide, ozone, peracids etc. as alternate of chlorine based bleach chemicals e.g. chlorine and chlorine dioxide etc. with the aim of eco-friend atmospheres. Changeover to the new chemicals in the bleaching process is likely to affect the metallurgy of the existing bleach plants due to change in the corrosivity of the media. Accordingly, corrosion investigations were performed in a peracid namely peracetic acid to test the suitability of austenitic stainless steels 654SMO, 265SMO, 2205, 317L and 316L. The performance of above stainless steels was evaluated through long term immersion tests and Electrochemical polarization measurements in peracetic acid (PAA bleach media at pH value 4 maintaining concentration 0.2 % as active oxygen along with three chloride levels 0, 500 and 1000 ppm in pulp-free laboratory. To study the effect of corrosion inhibitors with extending limit of chloride in liquors, measurements were also made with two types of chelants- EDTA & MgSO4. The results showed that corrosivity of PAA reduced by addition of chelant while increased with concentration of Cl¯. The results also exhibited that EDTA is better inhibitor than MgSO4.

  12. Potassium methyl siliconate-treated pulp fibers and their effects on wood plastic composites: Water sorption and dimensional stability

    Science.gov (United States)

    Cheng Piao; Zhiyong Cai; Nicole M. Stark; Charles J. Monlezun

    2013-01-01

    Potassium methyl siliconate (PMS) was investigated as a new nano modifier of wood fiber and wood flour to improve the compatibility between the fiber/flour and the plastic matrix in fiber reinforced plastic composites. Before injection molding, bleached and brown pulp fibers and mixed species wood flour were pretreated in PMS solutions. The morphology of the treated...

  13. Negotiation time table and realization timetable in the grid connection process according to KraftNAV; Verhandlungs- und Realisierungsfahrplan im Netzanschlussverfahren nach der KraftNAV

    Energy Technology Data Exchange (ETDEWEB)

    Buchmann, Felix [Sozietaet Alber Buchmann Stefan Rechtsanwaelte, Reutlingen (Germany)

    2010-04-15

    With the ordinance for the regulation of the grid connection from plants of power production (KraftNAV), the conditions of the grid connection were concretized by power station projects with a nominal output of at least 100 MW with an electrical potential of at least 110 kV. Under this aspect, the author of the contribution under consideration reports on the negotiation timetable and realization timetable in the grid connection procedure according to the KraftNAV. The following aspects are treated: Procedure for the grid connection according to KraftNAV in the overview; Promise of the connection and reservation fee; Negotiation timetable; Realization timetable; Requirement timetable; Duties to supply information.

  14. Flexible biorefinery for producing fermentation sugars, lignin and pulp from corn stover.

    Science.gov (United States)

    Kadam, Kiran L; Chin, Chim Y; Brown, Lawrence W

    2008-05-01

    A new biorefining process is presented that embodies green processing and sustainable development. In the spirit of a true biorefinery, the objective is to convert agricultural residues and other biomass feedstocks into value-added products such as fuel ethanol, dissolving pulp, and lignin for resin production. The continuous biomass fractionation process yields a liquid stream rich in hemicellulosic sugars, a lignin-rich liquid stream, and a solid cellulose stream. This paper generally discusses potential applications of the three streams and specifically provides results on the evaluation of the cellulose stream from corn stover as a source of fermentation sugars and specialty pulp. Enzymatic hydrolysis of this relatively pure cellulose stream requires significantly lower enzyme loadings because of minimal enzyme deactivation from nonspecific binding to lignin. A correlation was shown to exist between lignin removal efficiency and enzymatic digestibility. The cellulose produced was also demonstrated to be a suitable replacement for hardwood pulp, especially in the top ply of a linerboard. Also, the relatively pure nature of the cellulose renders it suitable as raw material for making dissolving pulp. This pulping approach has significantly smaller environmental footprint compared to the industry-standard kraft process because no sulfur- or chlorine-containing compounds are used. Although this option needs some minimal post-processing, it produces a higher value commodity than ethanol and, unlike ethanol, does not need extensive processing such as hydrolysis or fermentation. Potential use of low-molecular weight lignin as a raw material for wood adhesive production is discussed as well as its use as cement and feed binder. As a baseline application the hemicellulosic sugars captured in the hydrolyzate liquor can be used to produce ethanol, but potential utilization of xylose for xylitol fermentation is also feasible. Markets and values of these applications are

  15. Water requirements of the pulp and paper industry

    Science.gov (United States)

    Mussey, Orville D.

    1955-01-01

    Water, of varied qualities, is used for several purposes in the manufacture of pulp and paper, as a vehicle for transporting the constituents of paper in the paper machines; as process water for cooking wood chips to make pulp; as a medium for heat transfer; and for washing the pulpwood, the woodpulp, and the machines that handle the pulp. About 3,200 million gallons of water was withdrawn from surface- and ground-water sources each day during 1950 for the use of the pulp and paper industry. This is about 4 percent of the total estimated industrial withdrawal of water in the Nation The paper industry in the United States has been growing at a rapid rate. It has increased about tenfold in the last 50 years and has doubled every 15 years. The 1950 production of paper was about 24 million tons, which amounts to about 85 percent of the domestic consumption. In 1950, the pulp mills of the country produced more than 14 million tons of woodpulp, which supplied about 85 percent of the demand by the paper mills and other industries. The remainder of the fiber for paper manufacture was obtained from imported woodpulp, from reclaimed wastepaper, and from other fibers including rags and straw. The nationwide paper consumption for 1955 has been estimated at 31,700,000 tons. Woodpulp is classified according to the process by which it is made. Every woodpulp has characteristics that are carried over into the many and diverse grades of paper. Groundwood pulp is manufactured by simply grinding up wood and refining the resulting product. Soda, sulfite, and sulfate pulps are manufactured by chemically breaking down the lignin that cements the cellulose of the wood together and removing, cleaning, and sometimes bleaching the resulting fibers. Some woodpulp is produced by other methods. Sulfate-pulp mills are increasing in number and in rated daily capacity and are manufacturing more than half of the present domestic production of woodpulp. Most of the newer and larger woodpulp mills

  16. Microhardness of demineralized enamel following home bleaching and laser-assisted in office bleaching

    Science.gov (United States)

    Ghanbarzadeh, Majid; Akbari, Majid; Hamzei, Haniye

    2015-01-01

    Background There is little data regarding the effect of tooth whitening on microhardness of white spot lesions. This study was conducted to investigate the effect of home-bleaching and laser-assisted in-office bleaching on microhardness of demineralized enamel. Material and Methods Forty bovine incisors were selected and immersed in a demineralizing solution for 12 weeks to induce white spot lesions. Enamel blocks were prepared and randomly assigned to two groups of 20 each. The first group underwent home bleaching with 15% carbamide peroxide which was applied for 8 hours a day over a period of 15 days. In the second group, in-office bleaching was performed by 40% hydrogen peroxide and powered by irradiation from an 810 nm gallium-aluminum-arsenide (GaAlAs) diode laser (CW, 2W). This process was performed for 3 sessions every seven days, in 15 days. The specimens were stored in Fusayama Meyer artificial saliva during the experiment. Surface microhardness was assessed before and after the bleaching therapies in both groups. Results Microhardness decreased significantly following both home bleaching and laser-assisted in-office bleaching (pTooth whitening through home bleaching or laser-assisted in-office bleaching can result in a significant reduction in microhardness of white spot lesions. Therefore, it is suggested to take protective measures on bleached demineralized enamel. Key words:White spot lesion, bleaching, laser, microhardness, demineralized enamel, home bleaching, in-office bleaching. PMID:26330939

  17. Ultrasound-assisted extraction of arabinogalactan and dihydroquercetin simultaneously from Larix gmelinii as a pretreatment for pulping and papermaking.

    Directory of Open Access Journals (Sweden)

    Chunhui Ma

    Full Text Available An ultrasound-assisted extraction (UAE method using ethanol was applied for extracting arabinogalactan (AG and dihydroquercetin (DHQ simultaneously from larch wood, as a pretreatment for pulping and papermaking. The extraction parameters were optimized by a Box-Behnken experimental design with the yields of AG and DHQ as the response values. Under optimum conditions (three extractions, each using 40% ethanol, for 50 min, 200 W ultrasound power and 1∶18 solid-liquid ratio, the yields of AG and DHQ were 183.4 and 36.76 mg/g, respectively. After UAE pretreated, the wood chips were used for Kraft pulping (KP and high boiling solvent pulping (HBSP. The pulping yield after pretreatment was higher than that of untreated (the pulping yields of untreated HBSP and KP were 42.37% and 39.60%, and the pulping yields of HBSP and KP after UAE-pretreated were 44.23% and 41.50% respectively, as indicated by a lower kappa number (77.91 and 27.30 for untreated HBSP and KP; 77.01 and 26.83 for UAE-pretreated HBSP and KP. Furthermore, the characteristics of paper produced from pretreated wood chips were superior to those from the untreated chips: the basis weight was lower (85.67 and 82.48 g·cm(-2 for paper from untreated KP and HBSP; 79.94 and 80.25 g·cm(-2 for paper from UAE-pretreated KP and HBSP, and the tensile strengths, tearing strengths, bursting strengths, and folding strengths were higher than these of paper after UAE-pretreated, respectively.

  18. Novalignin project. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Stigsson, Lars [KIRAM AB, Saltsjoebaden (Sweden)

    2002-02-01

    The NovaFiber process is a new and sustainable technology for manufacturing of chemical pulp incorporating an efficient route for recovery of energy and pulping chemicals. The process is substantially sulphur chemicals free and this creates a great potential for recovery of sulphur free lignin for internal use as a fuel or export from the mill. The NovaLignin project has been launched to evaluate this potential from a technical and economical perspective. The NovaLignin research and development effort has been partly financed by NUTEK, Energimyndigheten and Mistra. A major feature of the new lignin is the absence of organically bound sulphur compounds in the material increasing the scope of potential uses for the lignin as a precursor for fine chemicals preparation or as a sulphur free biomass based fuel. Two major forest industry laboratories in Scandinavia have conducted the laboratory cooking and lignin extraction work in the present project. The lignin extracted from the NovaFiber process, NovaLignin, has been characterised and evaluated for use in different applications. The consequences of lignin extraction in different mill configurations with a recovery boiler or a black liquor gasification system for chemicals recovery is outlined below. The NovaFiber pulp mill is compared to a reference mill based on conventional kraft pulping on the same wood raw material. The mill capacity is 2000 t/d bleached softwood pulp. The lime kiln is fired with bark and the remaining falling bark is sold, or if there is a deficit, more bark is purchased. Initial laboratory studies conducted at ATO-DLO, the Netherlands, clearly show a great potential for NovaLignin as a functional additive in thermoplastics. NovaFiber and Kraft lignin act as an UV stabiliser for polyethylene at a comparable level as an expensive commercial stabiliser, such as HALS. This means that NovaFiber lignin has a very good price/performance ratio. Experiments show that NovaFiber lignin has good potential

  19. Materials for the pulp and paper industry. Section 1: Development of materials for black liquor recovery boilers

    Energy Technology Data Exchange (ETDEWEB)

    Keiser, J.R.; Hubbard, C.R.; Payzant, E.A. [Oak Ridge National Lab., TN (United States)] [and others

    1997-04-01

    Black liquor recovery boilers are essential components of kraft pulp and paper mills because they are a critical element of the system used to recover the pulping chemicals required in the kraft pulping process. In addition, the steam produced in these boilers is used to generate a significant portion of the electrical power used in the mill. Recovery boilers require the largest capital investment of any individual component of a paper mill, and these boilers are a major source of material problems in a mill. The walls and floors of these boilers are constructed of tube panels that circulate high pressure water. Molten salts (smelt) accumulate on the floor of recovery boilers, and leakage of water into the boiler can result in a violent explosion when the leaked water instantly vaporizes upon contacting the molten smelt. Because corrosion of the conventionally-used carbon steel tubing was found to be excessive in the lower section of recovery boilers, use of stainless steel/carbon steel co-extruded tubing was adopted for boiler walls to lessen corrosion and reduce the likelihood of smelt/water explosions. Eventually, this co-extruded or composite (as it is known in the industry) tubing was selected for use as a portion or all of the floor of recovery boilers, particularly those operating at pressures > 6.2 MPa (900 psi), because of the corrosion problems encountered in carbon steel floor tubes. Since neither the cause of the cracking nor an effective solution has been identified, this program was established to develop a thorough understanding of the degradation that occurs in the composite tubing used for walls and floors. This is being accomplished through a program that includes collection and review of technical reports, examination of unexposed and cracked tubes from boiler floors, computer modeling to predict residual stresses under operating conditions, and operation of laboratory tests to study corrosion, stress corrosion cracking, and thermal fatigue.

  20. Evolution of Lignocellulosic Macrocomponents in the Wastewater Streams of a Sulfite Pulp Mill: A Preliminary Biorefining Approach

    Directory of Open Access Journals (Sweden)

    Tamara Llano

    2015-01-01

    Full Text Available The evolution of lignin, five- and six-carbon sugars, and other decomposition products derived from hemicelluloses and cellulose was monitored in a sulfite pulp mill. The wastewater streams were characterized and the mass balances throughout digestion and total chlorine free bleaching stages were determined. Summative analysis in conjunction with pulp parameters highlights some process guidelines and valorization alternatives towards the transformation of the traditional factory into a lignocellulosic biorefinery. The results showed a good separation of cellulose (99.64% during wood digestion, with 87.23% of hemicellulose and 98.47% lignin dissolved into the waste streams. The following steps should be carried out to increase the sugar content into the waste streams: (i optimization of the digestion conditions increasing hemicellulose depolymerization; (ii improvement of the ozonation and peroxide bleaching stages, avoiding deconstruction of the cellulose chains but maintaining impurity removal; (iii fractionation of the waste water streams, separating sugars from the rest of toxic inhibitors for 2nd generation biofuel production. A total of 0.173 L of second-generation ethanol can be obtained in the spent liquor per gram of dry wood. The proposed methodology can be usefully incorporated into other related industrial sectors.

  1. Contents of constituents and antioxidant activity of seed and pulp extracts of Annona coriacea and Annona sylvatica

    Directory of Open Access Journals (Sweden)

    RSR. Benites

    Full Text Available AbstractThe antioxidant potential of fruit pulp and seeds of extracts of the Annona coriacea, and A. sylvatica(Annonaceae were investigated, as well contents total phenolics, flavonoids, condensed tannins and ascorbic acid. Was used to determine the antioxidant activity the 1,1-diphenyl-1-picrylhydrazyl free radical (DPPH, β-carotene bleaching and ABTS radical cation method. The total phenol, total flavonoid, condensed tannin, and ascorbic acid contents were measured spectrophotometrically. In this study, the pulp and seeds of the fruits were extracted using methanol/water (8:2 for maceration. The seed extracts of A. coriacea demonstrated a moderate antioxidant effect with free radical scavenging activity of 31.53%, by the DPPH test, 51.59% by the β-carotene bleaching test and 159.50 µM trolx/g of extract in the ABTS assay. We found that the hydromethanolic seed extract of A. coriacea had high total phenol (147.08 ± 4.20 mg of GAE/g of extract and flavonoid (131.18 ± 2.31 mg of QE/g of extract content. This indicated that the antioxidant activity of the extracts was related to the contents of these constituents.

  2. A comparative evaluation of explosion hazards in chemical and mechanical pulp bleaching systems

    Science.gov (United States)

    Peter W. Hart; Alan W. Rudie

    2010-01-01

    Over the past several years, at least three pulp mills in North America have experienced catastrophic events that resulted in the explosion of pumps, mixers, and tanks. All these mills were using 50% concentration hydrogen peroxide at the site of the explosions. In at least two instances, alkali catalyzed decomposition of peroxide is implicated in the explosion....

  3. Improved Wood Properties Through Genetic Manipulation: Engineering of Syringyl Lignin in Softwood Species Through Xylem-Specific Expression of Hardwood Syringyl Monolignol Pathway Genes

    Energy Technology Data Exchange (ETDEWEB)

    Chandrashekhar P. Joshi; Vincent L. Chiang

    2009-01-29

    Project Objective: Our long-term goal is to genetically engineer higher value raw materials with desirable wood properties to promote energy efficiency, international competitiveness, and environmental responsiveness of the U.S. forest products industry. The immediate goal of this project was to produce the first higher value softwood raw materials engineered with a wide range of syringyl lignin quantities. Summary: The most important wood property affecting directly the levels of energy, chemical and bleaching requirements for kraft pulp production is lignin. Softwoods contain almost exclusively chemically resistant guaiacyl (G) lignin, whereas hardwoods have more reactive or easily degradable lignins of the guaiacyl (G)-syringyl (S) type. It is also well established that the reactive S lignin component is the key factor that permits much lower effective alkali and temperature, shorter pulping time and less bleaching stages for processing hardwoods than for softwoods. Furthermore, our pulping kinetic study explicitly demonstrated that every increase in one unit of the lignin S/G ratio would roughly double the rate of lignin removal. These are clear evidence that softwoods genetically engineered with S lignin are keys to revolutionizing the energy efficiency and enhancing the environmental performance of this industry. Softwoods and hardwoods share the same genetic mechanisms for the biosynthesis of G lignin. However, in hardwoods, three additional genes branch out from the G-lignin pathway and become specifically engaged in regulating S lignin biosynthesis. In this research, we simultaneously transferred aspen S-specific genes into a model softwood, black spruce, to engineer S lignin.

  4. Efficacy of cold light bleaching using different bleaching times and their effects on human enamel.

    Science.gov (United States)

    Wang, Wei; Zhu, Yuhe; Li, Jiajia; Liao, Susan; Ai, Hongjun

    2013-01-01

    This study investigated the efficacy of cold light bleaching using different bleaching times and the effects thereof on tooth enamel. Before and after bleaching, stained tooth specimens were subjected to visual and instrumental colorimetric assessments using Vita Shade Guide and spectrophotometric shade matching. Enamel surface alterations were examined using scanning electron microscopy (SEM) to analyze surface morphology, surface microhardness (SMH) measurement to determine changes in mechanical properties, and X-ray diffraction (XRD) to characterize post-bleaching enamel composition. Cold light bleaching successfully improved tooth color, with optimal efficacy when bleaching time was beyond 10 min. Significant differences in surface morphology were observed among the different bleaching times, but no significant differences were observed for enamel composition and surface microhardness among the different bleaching times. Results of this study revealed an association between the bleaching time of cold light bleaching and its whitening efficacy. Together with the results on enamel surface changes, this study provided positive evidence to support cold light bleaching as an in-office bleaching treatment.

  5. A colourimetric evaluation of the effect of bacterial contamination on teeth stained with blood in vitro: Evaluation of the efficacy of two different bleaching regimes.

    Science.gov (United States)

    Wang, S; Cathro, P; Heithersay, G; Briggs, N; Ratnayake, J; Zilm, P

    2018-02-27

    Tooth discolouration could occur due to bacterial contamination in traumatized teeth. Hydrogen peroxide is the commonly used bleaching agent. However, due to concerns over safety, alternative bleaching regimes such as sodium perborate (S) and thiourea-hydrogen peroxide (T) have been investigated. Apices resected and pulp extirpated 99 premolars were divided into two groups. Group 1 and 2 was injected with blood and blood/bacteria, stored anaerobically for 35 days. The two groups were treated by bleaching with water, S or T. Teeth were rebleached after 7 days. Colourimetric evaluation was assessed using digital imaging, CasMatch standardization and CIE L*a*b colour system preoperatively, 35 days of staining and 7 and 14 of bleaching. A linear mixed model with fixed effects of time, group and bleach was used to examine colour difference. Blood-stained teeth were significantly redder and darker on day 35 compared with blood/bacteria-stained teeth. After bleaching, blood-stained teeth retained significant redness compared with blood/bacteria-stained teeth using either S or T. T produced a significantly whiter shade in both the groups after 14 days. Blood-stained teeth were significantly darker and red compared with blood/bacteria-stained teeth. T bleaching regime was more effective than S. © 2018 Australian Dental Association.

  6. 40 CFR 62.11610 - Identification of plan.

    Science.gov (United States)

    2010-07-01

    .... The Plan includes the following Kraft Pulp Mills: (1) Chesapeake Corporation, West Point; (2) Stone... operation (added), New design recovery furnace (added), Pulp and paper mill (added), Semichemical pulping...

  7. Effect of pH on production of xylanase by Trichoderma reesei on xylan- and cellulose-based media

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, M.J. (VTT, Biotechnical Lab., Espoo (Finland)); Buchert, J. (VTT, Biotechnical Lab., Espoo (Finland)); Viikari, L. (VTT, Biotechnical Lab., Espoo (Finland))

    1993-11-01

    Trichoderma reesei VTT-D-86271 (Rut C-30) was cultivated on media based on cellulose and xylan as the main carbon source in fermentors with different pH minimum controls. Production of xylanase was favoured by a rather high pH minimum control between 6.0 and 7.0 on both cellulose- and xylan-based media. Although xylanase was produced efficiently on cellulose as well as on xylan as the carbon source, significant production of cellulase was observed only on the cellulose-based medium and best production was at lower pH (4.0 minimum). Production of xylanase at pH 7.0 was shown to be dependent on the nature of the xylan in the cultivation medium but was independent of other organic components. Best production of xylanase was observed on insoluble, unsubstituted beech xylan at pH 7.0. Similar results were obtained in laboratory and pilot (200-1) fermentors. Downstream processing of the xylanase-rich, low-cellulase culture filtrate presented no technical problems despite apparent autolysis of the fungus at the high pH. Enzyme produced in the 200-1 pilot fermentor was shown to be suitable for use in enzyme-aided bleaching of kraft pulp. Due to the high xylanase/cellulase ratio of enzyme activities in the culture filtrate, pretreatment for removal of cellulase activity prior to pulp bleaching was unnecessary. (orig.)

  8. AVALIAÇÃO DAS PROPRIEDADES FÍSICO-MECÂNICAS DE POLPAS PRODUZIDAS POR NOVAS SEQUÊNCIAS DE BRANQUEAMENTO

    Directory of Open Access Journals (Sweden)

    Cristiane Pedrazzi

    2010-01-01

    Full Text Available The efficiency of oxygen delignification is very low for pulps of low number kappa and with high concentrations of hexenuronic acids, therefore the oxygen does not react with these acids, so being minimum the elimination of these during the oxygen delignification (pre-O2 in simple or double stage. In this study, the physicalmechanical properties of pulp of kappa number 17 and 14, produced with modified cooks and with the application of AD(EOD techniques for pulp of kappa 17 and DHT(EPODP for pulp of kappa 14 for the bleaching up to 90% ISO, had been investigated. The main objective of this study was to evaluate the physicalmechanical properties in pulps submitted to the bleaching sequences without oxygen in the beginning of the sequence. As references, cooks had been carried until numbers kappa 17 and 14, oxygen delignification and conventional bleaching for sequences A/D(EOD for pulp of kappa 17 and DHT(EPODP for pulp of kappa 14. The alternative bleaching, without pre-O2, resulted in bleached pulps with bigger integrity that of the reference, what it was confirmed by the values significantly higher of bulk, tear index, opacity and air resistance of the pulp weakly refined (for tissue papers. However, the high integrity of the fibers from pulps bleached with alternative processes lowered their conformabilities and collapsibility, with consequent reduction of tensile index of the pulp weakly refined. Therefore, with more intensive beating (for printing and writing papers, the tensile index was recovered. The high integrity of the bleaching pulps without pre-O2 makes beating difficulty. To reach the draining degree of 35°SR with the pulps proceeding from alternative processes of bleaching, it was necessary to apply 30% more energy than the reference.

  9. Grouping eucalyptus species in kraft pulp process for cost reduction

    Directory of Open Access Journals (Sweden)

    Apiwan Pichayadecha

    2014-12-01

    Full Text Available The objective of this research is to study the level of the important factors that can decrease total cost of pulp production. First of all, experts and experienced users identify the factors that affect the total production cost by applying the principle of 4M 1E cause and effect diagram. Then the primary factors were chosen based on 80% of their significance and tested by hypothesis for two population means. It was found that at the 95% confidence level the significant factors that have effects on the total production cost are amount of Effective alkali in white liquor and Kappa number. However, the proportion of easy delignification according to Eucalyptus species is considered as a significant factor based on various studies. Box-Behnken experiment is designed with respect to 3 mentioned factors and 3 levels of each factor. The response surface method (RSM is employed to determine the non-linear relation between the total cost as the response and the proportion of easy delignification, amount of Effective alkali in white liquor and Kappa number. To minimize the total cost, the optimal values of each factor are 75% of easy delignification, 112 grams per liter of Effective alkali in white liquor and 13.5 of kappa number. Under this optimal condition, the average total cost per ton of Eucalyptus is 13,393.91 Baht which is significantly less than the total cost of 15,517.06 Baht per ton before improvement.

  10. Synthesis and photobactericidal properties of a neutral porphyrin grafted onto lignocellulosic fibers

    Energy Technology Data Exchange (ETDEWEB)

    Nzambe Ta keki, Jean Kerim; Ouk, Tan-Sothéa [Laboratoire de chimie des substances naturelles, Université de Limoges, 123 avenue Albert Thomas, 87060 Limoges (France); Zerrouki, Rachida [Laboratoire de chimie des substances naturelles, Université de Limoges, 123 avenue Albert Thomas, 87060 Limoges (France); Centre de Recherche sur les Matériaux Lignocellulosiques, Université du Québec à Trois-Rivières, 3351 boul. des Forges, C.P. 500, Trois-Rivières, QC G9A 5H7 (Canada); Faugeras, Pierre-Antoine; Sol, Vincent [Laboratoire de chimie des substances naturelles, Université de Limoges, 123 avenue Albert Thomas, 87060 Limoges (France); Brouillette, François [Centre de Recherche sur les Matériaux Lignocellulosiques, Université du Québec à Trois-Rivières, 3351 boul. des Forges, C.P. 500, Trois-Rivières, QC G9A 5H7 (Canada)

    2016-05-01

    Photodynamic antimicrobial chemotherapy (PACT), as one of the promising alternative antimicrobial treatment, has received great attention in recent years. In this work, a new antimicrobial material has been elaborated by grafting a neutral porphyrin, the metallated 5-(4-azidophenyl)-10,15,20-triphenylporphyrin, onto lignocellulosic fibers by using the Copper (I)-Catalyzed Alkyne-Azide 1,3-dipolar Cycloaddition (CuAAC) reaction. The cross-linked porphyrin-Kraft pulp material was characterized by infrared and by XPS spectroscopy analyses, which proved the covalent linkage between the porphyrin and propargylated Kraft pulp fibers. The antimicrobial activity of this material was tested under visible light irradiation with a low light dose (9.5 J/cm{sup 2}) against Staphylococcus aureus and Pseudomonas aeruginosa. The two bacterial strains deposited on the resulting photosensitizing Kraft pulp are efficiently killed after illumination. Such materials could find applications in industrial, household and medical environments as an alternative to overcome the widespread microbial multiresistance to classical treatments. - Highlights: • Elaboration of new antimicrobial paper • Grafting of porphyrin on lignocellulosic fibers using click chemistry • Modification of Kraft pulp fibers, using water as solvent.

  11. Improved Materials for Use as Components in Kraft Black Liquor Recovery Boilers; TOPICAL

    International Nuclear Information System (INIS)

    Keiser, J.R.

    2001-01-01

    This Cooperative Research and Development Agreement (CRADA) was undertaken to evaluate current and improved materials and materials processing conditions for use as components in kraft black liquor recovery boilers and other unit processes. The main areas addressed were: (1) Improved Black Liquor Nozzles, (2) Weld Overlay of Composite Floor Tubes, and (3) Materials for Lime Kilns. Iron aluminide was evaluated as an alternate material for the nozzles used to inject an aqueous solution known as black liquor into recovery boilers as well for the uncooled lining in the ports used for the nozzles. Although iron aluminide is known to have much better sulfidation resistance in gases than low alloy and stainless steels, it did not perform adequately in the environment where it came into contact with molten carbonate, sulfide and sulfate salts. Weld overlaying carbon steel tubes with a layer of stainless weld metal was a proposed method of extending the life of recovery boiler floor tubes that have experienced considerable fireside corrosion. After exposure under service conditions, sections of weld overlaid floor tubes were removed from a boiler floor and examined metallographically. Examination results indicated satisfactory performance of the tubes. Refractory-lined lime kilns are a critical component of the recovery process in kraft pulp mills, and the integrity of the lining is essential to the successful operation of the kiln. A modeling study was performed to determine the cause of, and possible solutions for, the repeated loss of the refractory lining from the cooled end of a particular kiln. The evaluation showed that the temperature, the brick shape and the coefficient of friction between the bricks were the most important parameters influencing the behavior of the refractory lining

  12. Non-bleached colonies of massive Porites may attract fishes for selective grazing during mass bleaching events

    Directory of Open Access Journals (Sweden)

    Eri Ikeuchi

    2017-06-01

    Full Text Available In this study we investigated the variation in grazing scar densities between bleached and non-bleached colonies of massive Porites species in Sekisei Lagoon (Okinawa, southwestern Japan during a mass bleaching event in 2016. The grazing scar densities and bleaching susceptibility varied among neighboring colonies of massive Porites spp. However, non-bleached colonies had significantly more surface scars than bleached colonies. One explanation for these variations is that corallivorous fishes may selectively graze on non-bleached, thermally tolerant colonies. This is the first report of a relationship between grazing scars and the bleaching status of massive Porites spp. colonies during a mass bleaching event.

  13. Using Apparent Density of Paper from Hardwood Kraft Pulps to Predict Sheet Properties, based on Unsupervised Classification and Multivariable Regression Techniques

    Directory of Open Access Journals (Sweden)

    Ofélia Anjos

    2015-07-01

    Full Text Available Paper properties determine the product application potential and depend on the raw material, pulping conditions, and pulp refining. The aim of this study was to construct mathematical models that predict quantitative relations between the paper density and various mechanical and optical properties of the paper. A dataset of properties of paper handsheets produced with pulps of Acacia dealbata, Acacia melanoxylon, and Eucalyptus globulus beaten at 500, 2500, and 4500 revolutions was used. Unsupervised classification techniques were combined to assess the need to perform separated prediction models for each species, and multivariable regression techniques were used to establish such prediction models. It was possible to develop models with a high goodness of fit using paper density as the independent variable (or predictor for all variables except tear index and zero-span tensile strength, both dry and wet.

  14. Pulpal inflammation after vital tooth bleaching with 38% hydrogen peroxide

    Directory of Open Access Journals (Sweden)

    Ardiny Andriani

    2012-06-01

    Full Text Available Background: In-office vital tooth bleaching is a treatment to remove tooth stains. Tooth sensitivity is one of side effect commonly complained by patients receiving this treatment. Purpose: The aim of this study was to examine histological inflammatory cells infiltration of dental pulp after application of 38% H2O2 as a vital tooth bleaching agent. Methods: Under informed consent, a total of 15 premolars from 8 healthy subjects scheduled for orthodontic extraction were used in this study. Thirty eight percent H2O2 was applied on the buccal surface of the treated group. The treated teeth were extracted after 1 hour, 5, 8, and 15 days. All specimens were embedded in paraffin wax, sectioned serially and stained with Hematoxyllin Eosin. Histological specimens were then observed under a light microscope. Results: All treated groups showed a slight disorganization of odontoblasts layer and slight inflammation in the pulp tissue adjacent to the 38% H2O2 application site. The number of polymorphonuclear leukocytes (PMN had increased significantly 1 hour after application of 38% H2O2 (p<0.05, while macrophages had significantly increased 5 days after the application (p<0.05. The most intense PMN and macrophages infiltration was found 5 days after the application and gradually decreased 8 days after application of38% H2O2. Conclusion: Application of 38% H2O2 as a vital tooth bleaching agent induces acute inflammation in human dental pulp; however, the inflammation will decrease 8 days after the application.Latar belakang: Perawatan pemutihan gigi vital metode in-office merupakan tindakan untuk menghilangkan pewarnaan pada gigi. Salah satu efek samping yang sering dikeluhkan oleh pasien yang menjalani perawatan ini adalah sensitivitas gigi. Tujuan: Penelitian ini bertujuan untuk mengamati infiltrasi sel inflamasi pada pulpa gigi setelah aplikasi H2O2 38% sebagai bahan pemutih gigi. Metode: Sampel penelitian ini berupa 15 gigi premolar yang berasal dari 8

  15. Peroxy bleaches

    Energy Technology Data Exchange (ETDEWEB)

    Carson, P.A. [Unilever Research, Port Sunlight Laboratory (United States) and Chemistry Department, University of Manchester, Institute of Science and Technology (United States)]. E-mail: pcarson2005@aol.com; Fairclough, C.S. [Unilever Research, Port Sunlight Laboratory (United States); Mauduit, C. [Chemistry Department, University of Manchester, Institute of Science and Technology (United States); Colsell, M. [Chemistry Department, University of Manchester, Institute of Science and Technology (United States)

    2006-08-25

    Fabric laundering is now a sophisticated chemical process involving a variety of operations including bleaching. The chemistry of peroxy bleaches is described including the use of novel organic compounds to provide effective bleaching at the lower temperatures of modern wash cycles. The instability of peroxy compounds is illustrated using cameo case histories to relate theory and practice. Techniques available for determining their thermochemistry are summarised. A model is provided for hazard and risk assessment of development projects in general (particularly those involving new molecules, processes or formulations) from ideas phase through exploratory laboratory investigations to pilot plant scale-up and eventual manufacture and commercial exploitation. This paper is a prelude to Part 2, which describes the determination of thermodynamic and kinetic properties of peroxy bleaches and discusses the implication of the results in terms of precautions for their safe storage and incorporation into detergent formulations during processing.

  16. Peroxy bleaches

    International Nuclear Information System (INIS)

    Carson, P.A.; Fairclough, C.S.; Mauduit, C.; Colsell, M.

    2006-01-01

    Fabric laundering is now a sophisticated chemical process involving a variety of operations including bleaching. The chemistry of peroxy bleaches is described including the use of novel organic compounds to provide effective bleaching at the lower temperatures of modern wash cycles. The instability of peroxy compounds is illustrated using cameo case histories to relate theory and practice. Techniques available for determining their thermochemistry are summarised. A model is provided for hazard and risk assessment of development projects in general (particularly those involving new molecules, processes or formulations) from ideas phase through exploratory laboratory investigations to pilot plant scale-up and eventual manufacture and commercial exploitation. This paper is a prelude to Part 2, which describes the determination of thermodynamic and kinetic properties of peroxy bleaches and discusses the implication of the results in terms of precautions for their safe storage and incorporation into detergent formulations during processing

  17. Crown discoloration promoted by materials used in regenerative endodontic procedures and effect of dental bleaching: spectrophotometric analysis.

    Science.gov (United States)

    Santos, Luciane Geanini Pena Dos; Felippe, Wilson Tadeu; Souza, Beatriz Dulcineia Mendes de; Konrath, Andrea Cristina; Cordeiro, Mabel Mariela Rodríguez; Felippe, Mara Cristina Santos

    2017-01-01

    To assess tooth crown's color after intracanal treatment with triple antibiotic paste (TAP) or calcium hydroxide (CH); cervical sealing with glass ionomer cement (GIC) or mineral trioxide aggregate (MTA); and bleaching with carbamide peroxide. After pulp removal and color spectrophotometer measurement, 50 bovine incisors were divided into 4 experimental groups and one control (untreated). Experiments were performed in phases (Ph). Ph1: TAP (ciprofloxacin, metronidazole, minocycline), TAPM (ciprofloxacin, metronidazole, amoxicillin), DAP (ciprofloxacin, metronidazole), or CH treatment groups. After 1 and 3 days (d); 1, 2, 3 weeks (w); and 1, 2, 3 and 4 months (m), color was measured and medications were removed. Ph2: GIC or MTA cervical sealing, each using half of the specimens from each group. Color was assessed after 1d, 3d; 1w, 2w, 3w; 1m and 2m. Ph3: Two bleaching sessions, each followed by color measurement. Data were analyzed with ANOVA and post-hoc Holm-Sidak method. Ph1: Specimens of TAP group presented higher color alteration (ΔE) mean than those of TAPM group. No significant difference was found among TAP or TAPM and CH, DAP or Control groups. Ph2: cervical sealing materials showed no influence on color alteration. Ph3: Different ΔE means (from different groups), prior to bleaching, became equivalent after one bleaching session. TAP induces higher color alteration than TAPM; color alteration increases over time; cervical sealing material has no influence on color alteration; and, dental bleaching was able to recover, at least partially, the tooth crown's color.

  18. Final Technical Report Steam Cycle Washer for Unbleached Pulp

    Energy Technology Data Exchange (ETDEWEB)

    Starkey, Yvonne; Salminen, Reijo; Karlsnes, Andy

    2008-09-22

    through the pulping phases. Most water used in the pulping process ends up as warm waste water in the mill’s effluent discharge, which subsequently pollutes receiving waterways and carries an enormous amount of energy with it. Wash water reduction in brown stock washing with the Steam Cycle Washers (SCW) will save energy, up to 1+ million BTUs per ton of pulp in the evaporators alone. Reduction of liquid volume through bleaching stages will save process heat energy in the amount of 2+ million BTUs per ton of pulp, and as much as 80 – 100 kWhrs of electrical power per ton of pulp due to reduced pumping costs. Currently, the technical barriers to water reduction in chemical pulping are basically as follows: • conventional pulp washers wash the pulp at 10 - 14% consistency, • conventional pulp washers use 12 – 16 tons of wash water per ton of pulp, and • they leave 30 – 70 lbs of soda (Na2SO4) per ton of pulp as soda loss into the washed pulp. The amount of wash water in excess of the amount of process liquid in the pulp is called Dilution Factor (DF), even though it is not a factor in the mathematical sense but an addition. Modern pulp washing lines can wash efficiently with a DF of 3 but most pulp mills in the United States are washing with a DF of 5-7. Therefore, at 10% washing consistency 14-16 tons of wash water is required and 14% consistency requires 11-13 tons of wash water.

  19. [Vital pulp therapy of damaged dental pulp].

    Science.gov (United States)

    Xuedong, Zhou; Dingming, Huang; Jianguo, Liu; Zhengwei, Huang; Xin, Wei; Deqin, Yang; Jin, Zhao; Liming, Chen; Lin, Zhu; Yanhong, Li; Jiyao, Li

    2017-08-01

    The development of an expert consensus on vital pulp therapy can provide practical guidance for the improvement of pulp damage care in China. Dental pulp disease is a major type of illness that adversely affects human oral health. Pulp capping and pulpotomy are currently the main methods for vital pulp therapy. Along with the development of minimal invasion cosmetic dentistry, using different treatment technologies and materials reasonably, preserving healthy tooth tissue, and extending tooth save time have become urgent problems that call for immediate solution in dental clinics. This paper summarizes the experiences and knowledge of endodontic experts. We develop a clinical path of vital pulp therapy for clinical work by utilizing the nature, approach, and degree of pulp damage as references, defense and self-repairing ability of pulp as guidance, and modern technologies of diagnosis and treatment as means.

  20. A comprehensive program to develop correlations for the physical properties of Kraft black liquor. Interim report No. 2

    Energy Technology Data Exchange (ETDEWEB)

    Fricke, A.L.

    1990-12-01

    Experimental effort for the program to evaluate physical properties of kraft black liquors is now proceeding well. Experimental work includes pulping, liquor analysis, lignin purification and characterization, vapor-liquid equilibria, heat capacity, heats of solution and combustion, and viscosity measurements. Measurement of thermal conductivity has not yet begun. Collection of the data necessary for development of generalized correlations is proceeding, but will require about two more years. The digester is operating very well. It is now possible to operate the digester as a closed, rotating reactor or as a batch reactor with liquor circulation. When operated with liquor circulation, temperatures within the chip bed can be monitored during cooking. Cooking is reproducible, and cooks are being performed to produce liquors for experimental studies. The digester could be further modified to permit us to conduct rapid exchange batch pulping or to permit us to simulate continuous pulping. Liquors to be used in experimental studies are concentrated in our large scale evaporator or in our small scale evaporator. The large scale evaporator is used to concentrate liquors to about 50% solids for storage and for use in studies requiring high solids liquors. The small scale evaporator is used for preparing final samples to as high as 85% solids and for measuring vapor-liquid equilibria. Liquors are now routinely analyzed to determine all components, except higher molecular weight organic acids and extractives. Lignin determination by uv-visible means has been improved. Lignin purification from black liquor has been improved and lignin molecular weights are determined routinely. Work on lignin molecular weight distribution is still not satisfactory, but recent developments holds promise.

  1. rendimento e qualidade de fibras secundárias

    Directory of Open Access Journals (Sweden)

    Gustavo Ventorim

    2005-01-01

    Full Text Available In this study, Total Chlorine Free (TCF bleaching processes were evaluated for bleaching a secondary fiber of different origens. The samples were bleached to a target brightness of 78 % ISO. The results were interpreted on the basis of chemical cost to reach the target brightness, bleaching yield and bleached pulp quality as measured by viscosity, fluorescence and b* color coordinate. The ozone stage was responsible for improve TCF bleaching performance. The pulp bleached by sequences contained a ozone stage followed by chelation, without interstage washing (ZQ, and a final hydrogen peroxide stage unpressurized (P or pressurized with oxygen (PO, designed as (ZQ(PO showed good results. These sequences decreased pulp b* coordinate significantly and fluorescence slightly. For all three bleaching processes, it was determined that process yield is negatively affected by hot alkaline stages such as oxygen, O, peroxide, P, and peroxide pressurized with oxygen, (PO and also for the origin of the pulps of secondary fibers.

  2. Characterization and pulp refining activity of a Paenibacillus campinasensis cellulase expressed in Escherichia coli.

    Science.gov (United States)

    Ko, Chun-Han; Tsai, Chung-Hung; Lin, Po-Heng; Chang, Ko-Cheng; Tu, Jenn; Wang, Ya-Nang; Yang, Chien-Ying

    2010-10-01

    The Cel-BL11 gene from Paenibacillus campinasensis BL11 was cloned and expressed in Escherichia coli as a His-tag fusion protein. Zymographic analysis of the recombinant protein revealed cellulase activity corresponding to a protein with a 38-kDa molecular weight. The optimum temperature and pH for purified cellulase were 60 °C and pH 7.0, respectively. The enzyme retained more than 80% activity after 8h at 60 °C at pH 6 and 7. The cellulase has a Km of 11.25 mg/ml and a Vmax of 1250 μmol/min/mg with carboxylmethyl cellulose (CMC). Then enzyme was active on Avicel, swollen Avicel, CMC, barley β-glucan, laminarin in the presence of 100 mM acetate buffer. It was inhibited by Hg²⁺, Cu²⁺ and Zn²⁺. Significant kraft pulp refining energy saving, 10%, was exhibited by the pretreatment of this cellulase applied at 2 IU per gram of oven-dried pulp. Broad pH and temperature stability render this cellulase a convenient applicability toward current mainstream biomass conversion and other industrial processes. Copyright © 2010 Elsevier Ltd. All rights reserved.

  3. Bleaching of Wool with Sodium Borohydride

    OpenAIRE

    Duygu Yilmazer, MSc.; Mehmet Kanik, Ph.D.

    2009-01-01

    An untreated wool fabric was bleached both with sodium borohydride (SBH) in the presence of sodium bisulphite (SBS) solution and with a commercial H2O2 bleaching method. The concentration effects of SBH and SBS, bleaching time, pH and temperature on SBH bleaching process were investigated. Whiteness, yellowness and alkali solubility results were assessed for both bleaching methods. The results showed that whiteness degrees obtained with SBH bleaching was comparable with that of H2O2 bleaching...

  4. Opalescence of bleached teeth.

    Science.gov (United States)

    Schmeling, Max; Maia, Hamilton Pires; Baratieri, Luiz Narciso

    2012-07-01

    To evaluate the influence of tooth bleaching on the opalescence properties of enamel. Color of 38 specimens was determined by colorimetric analysis before and after bleaching in the reflectance and transmittance modes. The results were described as CIELab color coordinates. The Opalescent Parameter (OP) was calculated as the difference in yellow-blue color coordinate (CIE Δb*) and red-green color coordinate (CIE Δa*) between the reflected and transmitted colors. Mean OP value of the specimens was 18.9 (±1.6) before bleaching and 16.1 (±1.0) after bleaching. Bleaching decreases the OP of the specimens (p>0.001). OP decrease was correlated with differences in b* color coordinate in the transmittance mode. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Reactivity of syringyl and guaiacyl lignin units and delignification kinetics in the kraft pulping of Eucalyptus globulus wood using Py-GC-MS/FID.

    Science.gov (United States)

    Lourenço, Ana; Gominho, Jorge; Marques, António Velez; Pereira, Helena

    2012-11-01

    Eucalyptus globulus sapwood and heartwood showed no differences in lignin content (23.0% vs. 23.7%) and composition: syringyl-lignin (17.9% vs. 18.0%) and guaiacyl-lignin (4.8% vs. 5.2%). Delignification kinetics of S- and G-units in heartwood and sapwood was investigated by Py-GC-MS/FID at 130, 150 and 170°C and modeled as double first-order reactions. Reactivity differences between S and G-units were small during the main pulping phase and the higher reactivity of S over G units was better expressed in the later pulping stage. The residual lignin composition in pulps was different from wood or from samples in the initial delignification stages, with more G and H-units. S/G ratio ranged from 3 to 4.5 when pulp residual lignin was higher than 10%, decreasing rapidly to less than 1. The S/H was initially around 20 (until 15% residual lignin), decreasing to 4 when residual lignin was about 3%. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Short communication: The influence of solids concentration and bleaching agent on bleaching efficacy and flavor of sweet whey powder.

    Science.gov (United States)

    Jervis, M G; Smith, T J; Drake, M A

    2015-04-01

    Recent studies have demonstrated the effect of bleaching conditions and bleaching agent on flavor and functional properties of whey protein ingredients. Solids concentration at bleaching significantly affected bleaching efficacy and flavor effects of different bleaching agents. It is not known if these parameters influence quality of sweet whey powder (SWP). The purpose of this study was to determine the effects of solids concentration and bleaching agent on the flavor and bleaching efficacy of SWP. Colored cheddar whey was manufactured, fat separated, and pasteurized. Subsequently, the whey (6.7% solids) was bleached, concentrated using reverse osmosis (RO) to 14% solids, and then spray dried, or whey was concentrated before bleaching and then spray dried. Bleaching treatments included a control (no bleaching, 50 °C, 60 min), hydrogen peroxide (HP; 250 mg/kg, 50 °C, 60 min), benzoyl peroxide (50 mg/kg, 50 °C, 60 min), lactoperoxidase (20 mg/kg of HP, 50 °C, 30 min), and external peroxidase (MaxiBright, DSM Food Specialties, Delft, the Netherlands; 2 dairy bleaching units/mL, 50 °C, 30 min). The experiment was repeated in triplicate. Sensory properties and volatile compounds of SWP were evaluated by a trained panel and gas chromatography-mass spectrometry, respectively. Bleaching efficacy (norbixin destruction) and benzoic acid were measured by HPLC. Differences in bleaching efficacy, sensory and volatile compound profiles, and benzoic acid were observed with different bleaching agents, consistent with previous studies. Solids concentration affected bleaching efficacy of HP, but not other bleaching agents. The SWP from whey bleached with HP or lactoperoxidase following RO had increased cardboard and fatty flavors and higher concentrations of lipid oxidation compounds compared with SWP from whey bleached before RO. The SWP bleached with benzoyl peroxide after RO contained less benzoic acid than SWP from whey bleached before RO. These results indicate that

  7. Red algae and their use in papermaking.

    Science.gov (United States)

    Seo, Yung-Bum; Lee, Youn-Woo; Lee, Chun-Han; You, Hack-Chul

    2010-04-01

    Gelidialian red algae, that contain rhizoidal filaments, except the family Gelidiellaceae were processed to make bleached pulps, which can be used as raw materials for papermaking. Red algae consist of rhizoidal filaments, cortical cells usually reddish in color, and medullary cells filled with mucilaginous carbohydrates. Red algae pulp consists of mostly rhizoidal filaments. Red algae pulp of high brightness can be produced by extracting mucilaginous carbohydrates after heating the algae in an aqueous medium and subsequently treating the extracted with bleaching chemicals. In this study, we prepared paper samples from bleached pulps obtained from two red algae species (Gelidium amansii and Gelidium corneum) and compared their properties to those of bleached wood chemical pulps. Copyright 2009 Elsevier Ltd. All rights reserved.

  8. Body image disturbance and skin bleaching.

    Science.gov (United States)

    Charles, Christopher A D; McLean, Shua-Kym

    2017-11-01

    This study looks at body image disturbance among Jamaicans who bleach their skin. The hypothesis states that there is a positive relationship between skin bleaching and body image disturbance. The study used a convenience sample of 160 participants with a skin bleaching group (n = 80) and a non-bleaching comparison group (n = 80). The instrument included demographic questions, the body image disturbance questionnaire (BIDQ), and questions about skin bleaching. The results of a t-test revealed that the skin bleaching group (M = 1.5255, SD = 0.42169) was not significantly different from the non-bleaching group (M = 1.4938, SD = 0.74217) in terms of body image disturbance, t(158) = 0.333, p = .740. The participants who bleached did not suffer from body image disturbance. Self-reports revealed that they bleached to acquire beauty, attract a partner, elude the police, and market skin bleaching products. The practice was fashionable and popular and it made some participants feel good, while others were fans of a popular musical artiste who bleached his skin. The majority of participants bleached because of the perceived personal, social, and entrepreneurial benefits of the practice and not because they suffered emotional distress, anxiety, and functional impairment because of their skin colour. However, there was some level of BID among the minority of participants who argued that they bleached because they wanted to be pretty so they were emotionally distressed about there body image and experienced functional impairment. © 2017 The British Psychological Society.

  9. Bleaching and enamel surface interactions resulting from the use of highly-concentrated bleaching gels.

    Science.gov (United States)

    Grazioli, Guillermo; Valente, Lisia Lorea; Isolan, Cristina Pereira; Pinheiro, Helena Alves; Duarte, Camila Gonçalves; Münchow, Eliseu Aldrighi

    2018-03-01

    Tooth bleaching is considered a non-invasive treatment, although the use of highly-concentrated products may provoke increased surface roughness and enamel demineralization, as well as postoperative sensitivity. Thus, the aim of this study was to investigate whether hydrogen peroxide (H 2 O 2 ) concentration would affect tooth bleaching effectiveness and the enamel surface properties. Enamel/dentin bovine specimens (6 × 4 mm) were immersed in coffee solution for 7 days and evaluated with a spectrophotometer (Easyshade; baseline), using the CIEL * a * b * color parameters. Hardness was measured using a hardness tester. The specimens were randomly assigned into four groups: one negative control, in which the specimens were not bleached, but they were irradiated with a laser-light source (Whitening Lase II, DMC Equipments); and three groups using distinct H 2 O 2 concentration, namely LP15% (15% Lase Peroxide Lite), LP25% (25% Lase Peroxide Sensy), and LP35% (35% Lase Peroxide Sensy), all products from DMC. The bleached specimens were also irradiated with the laser-light source. After bleaching, all specimens were evaluated using scanning electron microscopy (SEM). pH kinetics and rate was monitored during bleaching. The data were analyzed using ANOVA and Tukey's test (p bleaching gels produced similar color change (p > 0.05). Concerning hardness, only the LP25% and LP35% significantly reduced hardness after bleaching; also, there was a progressive tendency for a greater percentage reduction in hardness with increased H 2 O 2 concentration of the gel (R 2  = 0.9973, p bleaching effectiveness, and may increase the possibility for alteration of enamel hardness, surface morphology, and acidity of the medium. When using H 2 O 2 -based bleaching agents, dental practitioners should choose for less concentrated gels, e.g., around the 15% level. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Coronal microleakage with five different temporary restorative materials following walking bleach technique: An ex-vivo study

    Directory of Open Access Journals (Sweden)

    G. P. V Srikumar

    2012-01-01

    Full Text Available Context: Walking bleach technique uses 30% hydrogen peroxide and sodium perborate, and this paste mixture causes loosening of the coronal temporary restorative materials and thus decreasing its clinical effectiveness and causing irritation to the patients oral tissues. In the present study, sealing ability of hygroscopic coronal temporary restorative materials were compared with the other commonly used temporary restorative materials. Aim: To evaluate the effects of walking bleach material on the marginal sealing ability and coronal microleakage of the hydrophilic temporary restorative materials with that of the other commonly used temporary restorative materials in endodontic practice. Materials and Methods: Seventy-five extracted human maxillary central incisor teeth were prepared chemo-mechanically and obturated with gutta-percha in lateral condensation technique. Surface of each tooth was double coated with cyanoacrylate glue. All the teeth were randomly divided in to five groups. Out of 15 teeth in each group, 10 teeth served as experimental specimens, in which bleaching agent was placed in the pulp chamber and 5 teeth served as control, in which no bleaching agent was placed. The access cavities were restored with temporary restorative materials being tested per each group respectively. The specimens were then immersed in 1% India ink dye and subjected to thermo cycling for 7 days. All the teeth were longitudinally sectioned and observed with stereomicroscope and were graded according to the depth of linear dye penetration. Statistical Analysis Used: Mann-Whitney U test and Kruskal-Wallis test. Results: Hydrophilic temporary restorative materials Cavit G and Coltosol F have shown minimal coronal dye leakage with better sealing ability when exposed to walking bleach paste mixture in the dye penetration tests compared to other commonly used temporary restorative materials. Conclusion: Marginal sealing ability of Cavit G and Coltosol F were

  11. Bleaching of cotton fabric with tetraacetylhydrazine as bleach activator for H2O2.

    Science.gov (United States)

    Liu, Kai; Zhang, Xuan; Yan, Kelu

    2018-05-15

    Tetraacetylhydrazine (TH) as bleach activator for H 2 O 2 cotton bleaching was synthesized and characterized by 1 H NMR, 13 C NMR and MS spectra. TH has better solubility than that of TAED. The CIE whiteness index (WI), H 2 O 2 decomposition rate and bursting strength were employed to investigate the performance of H 2 O 2 /TH bleaching system. By addition of TH, WI and H 2 O 2 decomposition rate increased significantly at 70 °C. Bleaching temperature, NaHCO 3 concentration and bleaching time were also discussed in detail and the loss of bursting strength is not clear. By using benzenepentacarboxylic acid (BA) as a fluorescent probe for hydroxyl radical detection, the bleaching process of H 2 O 2 /TH system was investigated. Acetylhydrazine and diacetylhydrazine were also utilized to further confirm the process. In addition, bimolecular decomposition was investigated by using 9,10-dimethylanthracene (DMA) as fluorescent probe of 1 O 2 . Based on these experimental results, the bleaching mechanism of H 2 O 2 /TH system was proposed. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. Changes in bleaching susceptibility among corals subject to ocean warming and recurrent bleaching in Moorea, French Polynesia.

    Science.gov (United States)

    Pratchett, Morgan S; McCowan, Dominique; Maynard, Jeffrey A; Heron, Scott F

    2013-01-01

    Climate-induced coral bleaching poses a major threat to coral reef ecosystems, mostly because of the sensitivities of key habitat-forming corals to increasing temperature. However, susceptibility to bleaching varies greatly among coral genera and there are likely to be major changes in the relative abundance of different corals, even if the wholesale loss of corals does not occur for several decades. Here we document variation in bleaching susceptibility among key genera of reef-building corals in Moorea, French Polynesia, and compare bleaching incidence during mass-bleaching events documented in 1991, 1994, 2002 and 2007. This study compared the proportion of colonies that bleached for four major genera of reef-building corals (Acropora, Montipora, Pocillopora and Porites), during each of four well-documented bleaching events from 1991 to 2007. Acropora and Montipora consistently bleached in far greater proportions (up to 98%) than Pocillopora and Porites. However, there was an apparent and sustained decline in the proportion of colonies that bleached during successive bleaching events, especially for Acropora and Montipora. In 2007, only 77% of Acropora colonies bleached compared with 98% in 1991. Temporal variation in the proportion of coral colonies bleached may be attributable to differences in environmental conditions among years. Alternately, the sustained declines in bleaching incidence among highly susceptible corals may be indicative of acclimation or adaptation. Coral genera that are highly susceptible to coral bleaching, and especially Acropora and Montipora, exhibit temporal declines in their susceptibility to thermal anomalies at Moorea, French Polynesia. One possible explanation for these findings is that gradual removal of highly susceptible genotypes (through selective mortality of individuals, populations, and/or species) is producing a coral assemblage that is more resistant to sustained and ongoing ocean warming.

  13. Changes in Bleaching Susceptibility among Corals Subject to Ocean Warming and Recurrent Bleaching in Moorea, French Polynesia

    Science.gov (United States)

    Pratchett, Morgan S.; McCowan, Dominique; Maynard, Jeffrey A.; Heron, Scott F.

    2013-01-01

    Background Climate-induced coral bleaching poses a major threat to coral reef ecosystems, mostly because of the sensitivities of key habitat-forming corals to increasing temperature. However, susceptibility to bleaching varies greatly among coral genera and there are likely to be major changes in the relative abundance of different corals, even if the wholesale loss of corals does not occur for several decades. Here we document variation in bleaching susceptibility among key genera of reef-building corals in Moorea, French Polynesia, and compare bleaching incidence during mass-bleaching events documented in 1991, 1994, 2002 and 2007. Methodology/Principal Findings This study compared the proportion of colonies that bleached for four major genera of reef-building corals (Acropora, Montipora, Pocillopora and Porites), during each of four well-documented bleaching events from 1991 to 2007. Acropora and Montipora consistently bleached in far greater proportions (up to 98%) than Pocillopora and Porites. However, there was an apparent and sustained decline in the proportion of colonies that bleached during successive bleaching events, especially for Acropora and Montipora. In 2007, only 77% of Acropora colonies bleached compared with 98% in 1991. Temporal variation in the proportion of coral colonies bleached may be attributable to differences in environmental conditions among years. Alternately, the sustained declines in bleaching incidence among highly susceptible corals may be indicative of acclimation or adaptation. Conclusions/Significance Coral genera that are highly susceptible to coral bleaching, and especially Acropora and Montipora, exhibit temporal declines in their susceptibility to thermal anomalies at Moorea, French Polynesia. One possible explanation for these findings is that gradual removal of highly susceptible genotypes (through selective mortality of individuals, populations, and/or species) is producing a coral assemblage that is more resistant to

  14. Treatment of pulp and paper industry bleaching effluent by electrocoagulant process

    International Nuclear Information System (INIS)

    Sridhar, R.; Sivakumar, V.; Prince Immanuel, V.; Prakash Maran, J.

    2011-01-01

    The experiments were carried out in an electrocoagulation reactor with aluminum as sacrificial electrodes. The influence of electrolysis time, current density, pH, NaCl concentration, rotational speed of the stirrer and electrode distance on reduction of color, COD and BOD were studied in detail. From the experimental results, 15 mA/cm 2 current density, pH of 7, 1 g/l NaCl, 100 rpm, 28 deg, C temperature and 3 cm electrode distance were found to be optimum for maximum reduction of color, COD and BOD. The reduction of color, COD and BOD under the optimum condition were found to be 94%, 90% and 87% respectively. The electrode energy consumption was calculated and found to be varied from 10.1 to 12.9 kWh/m 3 depending on the operating conditions. Under optimal operating condition such as 15 mA/cm 2 current density, pH of 7, 1 g/l NaCl, 100 rpm, 28 deg, C temperature and 3 cm electrode distance, the operating cost was found to be 1.56 US $/m 3 . The experimental results proved that the electrocoagulation is a suitable method for treating bleaching plant effluents for reuse.

  15. Bleaching Dengan Teknologi Laser

    OpenAIRE

    Eliwaty

    2008-01-01

    Penulisan tentang bleaching dengan laser dimaksudkan untuk menambah wawasan serta pengetahuan dari pembaca di bidang kedokteran gigi. Macam-macam laser yang dipergunakan dalam bleaching yaitu argon, CO2 serta dioda laser. Contoh merek produk laser yaitu Blulaze, Dentcure untuk argonlaser, Novapulse untuk C02 serta Opus 5 untuk dioda laser. Laser bleaching hasilnya dapat dicapai dalam satu kunjungan saja, cepat, efisien namun biayanya relatif mahal, dapat menimbulkan burn, sensitivitas se...

  16. 40 CFR 98.190 - Definition of the source category.

    Science.gov (United States)

    2010-07-01

    .... (a) Lime manufacturing plants (LMPs) engage in the manufacture of a lime product (e.g., calcium oxide, high-calcium quicklime, calcium hydroxide, hydrated lime, dolomitic quicklime, dolomitic hydrate, or... kraft pulp mill, soda pulp mill, sulfite pulp mill, or only processes sludge containing calcium...

  17. Decellularized Swine Dental Pulp as a Bioscaffold for Pulp Regeneration.

    Science.gov (United States)

    Hu, Lei; Gao, Zhenhua; Xu, Junji; Zhu, Zhao; Fan, Zhipeng; Zhang, Chunmei; Wang, Jinsong; Wang, Songlin

    2017-01-01

    Endodontic regeneration shows promise in treating dental pulp diseases; however, no suitable scaffolds exist for pulp regeneration. Acellular natural extracellular matrix (ECM) is a favorable scaffold for tissue regeneration since the anatomical structure and ECM of the natural tissues or organs are well-preserved. Xenogeneic ECM is superior to autologous or allogeneic ECM in tissue engineering for its unlimited resources. This study investigated the characteristics of decellularized dental pulp ECM from swine and evaluated whether it could mediate pulp regeneration. Dental pulps were acquired from the mandible anterior teeth of swine 12 months of age and decellularized with 10% sodium dodecyl sulfate (SDS) combined with Triton X-100. Pulp regeneration was conducted by seeding human dental pulp stem cells into decellularized pulp and transplanted subcutaneously into nude mice for 8 weeks. The decellularized pulp demonstrated preserved natural shape and structure without any cellular components. Histological analysis showed excellent ECM preservation and pulp-like tissue, and newly formed mineralized tissues were regenerated after being transplanted in vivo. In conclusion, decellularized swine dental pulp maintains ECM components favoring stem cell proliferation and differentiation, thus representing a suitable scaffold for improving clinical outcomes and functions of teeth with dental pulp diseases.

  18. In vitro effect of low intensity laser on the cytotoxicity produced by substances released by bleaching gel

    Directory of Open Access Journals (Sweden)

    Caroline Maria Gomes Dantas

    2010-12-01

    Full Text Available This in vitro study aimed to analyze the effect of different parameters of phototherapy with low intensity laser on the viability of human dental pulp fibroblasts under the effect of substances released by bleaching gel. Cells were seeded into 96 wells plates (1 x 10³ cells/well and placed in contact with culture medium conditioned by a 35 % hydrogen peroxide bleaching gel for 40 minutes, simulating the clinical condition of the in-office bleaching treatment. Cells cultured in ideal growth conditions served as positive control group (PC, and the cells grown in conditioned medium and non-irradiated served as negative control group (NC. Cells grown in conditioned medium were submitted to a single irradiation with a diode laser (40 mW, 0.04 cm² emitting at visible red (660 nm; RL or near infrared (780 nm; NIR using punctual technique, in contact mode and energy densities of 4, 6 or 10 J/cm². The cell viability was analyzed through the MTT reduction assay immediately and 24 hours after the irradiation. The data was compared by ANOVA followed by the Tukey's test (p < 0.05. The cell viability increased significantly in 24 hours within each group. The PC presented cell viability significantly higher than NC in both experimental times. Only the NIR/10 J/cm² group presented cell viability similar to that of PC in 24 hours. The phototherapy with low intensity laser in defined parameters is able to compensate the cytotoxic effects of substances released by 35 % hydrogen peroxide bleaching gel.

  19. Decellularized Swine Dental Pulp as a Bioscaffold for Pulp Regeneration

    Directory of Open Access Journals (Sweden)

    Lei Hu

    2017-01-01

    Full Text Available Endodontic regeneration shows promise in treating dental pulp diseases; however, no suitable scaffolds exist for pulp regeneration. Acellular natural extracellular matrix (ECM is a favorable scaffold for tissue regeneration since the anatomical structure and ECM of the natural tissues or organs are well-preserved. Xenogeneic ECM is superior to autologous or allogeneic ECM in tissue engineering for its unlimited resources. This study investigated the characteristics of decellularized dental pulp ECM from swine and evaluated whether it could mediate pulp regeneration. Dental pulps were acquired from the mandible anterior teeth of swine 12 months of age and decellularized with 10% sodium dodecyl sulfate (SDS combined with Triton X-100. Pulp regeneration was conducted by seeding human dental pulp stem cells into decellularized pulp and transplanted subcutaneously into nude mice for 8 weeks. The decellularized pulp demonstrated preserved natural shape and structure without any cellular components. Histological analysis showed excellent ECM preservation and pulp-like tissue, and newly formed mineralized tissues were regenerated after being transplanted in vivo. In conclusion, decellularized swine dental pulp maintains ECM components favoring stem cell proliferation and differentiation, thus representing a suitable scaffold for improving clinical outcomes and functions of teeth with dental pulp diseases.

  20. Paper pulp-based adsorbents for the removal of pharmaceuticals from wastewater: A novel approach towards diversification.

    Science.gov (United States)

    Oliveira, Gonçalo; Calisto, Vânia; Santos, Sérgio M; Otero, Marta; Esteves, Valdemar I

    2018-08-01

    In this work, two pulps, bleached (BP) and raw pulp (RP), derived from the paper production process, were used as precursors of non-activated and activated carbons (ACs). In the case of non-ACs, the production involved either pyrolysis or pyrolysis followed by acid washing. For ACs production, the pulps were impregnated with K 2 CO 3 or H 3 PO 4 , and then pyrolysed and acid washed. After production, the materials were physically and chemically characterized. Then, batch adsorption tests on the removal of two pharmaceuticals (the anti-epileptic carbamazepine (CBZ) and the antibiotic sulfamethoxazole (SMX)) from ultra-pure water and from Waste Water Treatment Plant (WWTP) effluents were performed. In ultra-pure water, non-ACs were not able to adsorb CBZ or SMX while ACs showed good adsorption capacities. In WWTP effluents, although ACs satisfactorily adsorbed CBZ and SMX, they showed lower adsorption capacities for the latter. Tests with WWTP effluents revealed that the best adsorption capacities were achieved by carbons produced from BP and activated with H 3 PO 4 : 92±19mgg -1 for CBZ and 13.0±0.6mgg -1 for SMX. These results indicate the potential of paper pulps as precursors for ACs that can be applied in wastewater treatment. Copyright © 2018 Elsevier B.V. All rights reserved.

  1. Expression profiling and gene ontology analysis in fathead minnow (Pimephales promelas) liver following exposure to pulp and paper mill effluents

    Energy Technology Data Exchange (ETDEWEB)

    Costigan, Shannon L.; Werner, Julieta; Ouellet, Jacob D.; Hill, Lauren G. [Department of Biology, Lakehead University, 955 Oliver Road, Ontario P7B 5E1, (Canada); Law, R. David, E-mail: dlaw@lakeheadu.ca [Department of Biology, Lakehead University, 955 Oliver Road, Ontario P7B 5E1, (Canada)

    2012-10-15

    Many studies link pulp and paper mill effluent (PPME) exposure to adverse effects in fish populations present in the mill receiving environments. These impacts are often characteristic of endocrine disruption and may include impaired reproduction, development and survival. While these physiological endpoints are well-characterized, the molecular mechanisms causing them are not yet understood. To investigate changes in gene transcription induced by exposure to a PPME at several stages of treatment, male and female fathead minnows (FHMs) were exposed for 6 days to 25% (v/v) secondary (biologically) treated kraft effluent (TK) or 100% (v/v) combined mill outfall (CMO) from a mill producing both kraft pulp and newsprint. The gene expression changes in the livers of these fish were analyzed using a 22 K oligonucleotide microarray. Exposure to TK or CMO resulted in significant changes in the expression levels of 105 and 238 targets in male FHMs and 296 and 133 targets in females, respectively. Targets were then functionally analyzed using gene ontology tools to identify the biological processes in fish hepatocytes that were affected by exposure to PPME after its secondary treatment. Proteolysis was affected in female FHMs exposed to both TK and CMO. In male FHMs, no processes were affected by TK exposure, while sterol, isoprenoid, steroid and cholesterol biosynthesis and electron transport were up-regulated by CMO exposure. The results presented in this study indicate that short-term exposure to PPMEs affects the expression of reproduction-related genes in the livers of both male and female FHMs, and that secondary treatment of PPMEs may not neutralize all of their metabolic effects in fish. Gene ontology analysis of microarray data may enable identification of biological processes altered by toxicant exposure and thus provide an additional tool for monitoring the impact of PPMEs on fish populations.

  2. Expression profiling and gene ontology analysis in fathead minnow (Pimephales promelas) liver following exposure to pulp and paper mill effluents

    International Nuclear Information System (INIS)

    Costigan, Shannon L.; Werner, Julieta; Ouellet, Jacob D.; Hill, Lauren G.; Law, R. David

    2012-01-01

    Many studies link pulp and paper mill effluent (PPME) exposure to adverse effects in fish populations present in the mill receiving environments. These impacts are often characteristic of endocrine disruption and may include impaired reproduction, development and survival. While these physiological endpoints are well-characterized, the molecular mechanisms causing them are not yet understood. To investigate changes in gene transcription induced by exposure to a PPME at several stages of treatment, male and female fathead minnows (FHMs) were exposed for 6 days to 25% (v/v) secondary (biologically) treated kraft effluent (TK) or 100% (v/v) combined mill outfall (CMO) from a mill producing both kraft pulp and newsprint. The gene expression changes in the livers of these fish were analyzed using a 22 K oligonucleotide microarray. Exposure to TK or CMO resulted in significant changes in the expression levels of 105 and 238 targets in male FHMs and 296 and 133 targets in females, respectively. Targets were then functionally analyzed using gene ontology tools to identify the biological processes in fish hepatocytes that were affected by exposure to PPME after its secondary treatment. Proteolysis was affected in female FHMs exposed to both TK and CMO. In male FHMs, no processes were affected by TK exposure, while sterol, isoprenoid, steroid and cholesterol biosynthesis and electron transport were up-regulated by CMO exposure. The results presented in this study indicate that short-term exposure to PPMEs affects the expression of reproduction-related genes in the livers of both male and female FHMs, and that secondary treatment of PPMEs may not neutralize all of their metabolic effects in fish. Gene ontology analysis of microarray data may enable identification of biological processes altered by toxicant exposure and thus provide an additional tool for monitoring the impact of PPMEs on fish populations.

  3. 40 CFR 63.861 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... Unit no. HD-14. Kraft pulp mill means any stationary source that produces pulp from wood by cooking... cooking (digesting) wood chips in a solution of sulfurous acid and bisulfite ions. The recovery process...

  4. Treatment of pulp and paper industry bleaching effluent by electrocoagulant process

    Energy Technology Data Exchange (ETDEWEB)

    Sridhar, R., E-mail: sridhar36k@yahoo.co.in [Department of Chemical Engineering, Kongu Engineering College, Perundurai, Erode 638052, TN (India); Sivakumar, V., E-mail: drvsivakumar@yahoo.com [Department of Food Technology, Kongu Engineering College, Perundurai, Erode 638052, TN (India); Prince Immanuel, V., E-mail: princeimmanuel79@yahoo.com [Department of Chemical Engineering, Erode Sengunthar Engineering College, Thudupathi, Erode 638057, TN (India); Prakash Maran, J., E-mail: prakashmaran@gmail.com [Department of Food Technology, Kongu Engineering College, Perundurai, Erode 638052, TN (India)

    2011-02-28

    The experiments were carried out in an electrocoagulation reactor with aluminum as sacrificial electrodes. The influence of electrolysis time, current density, pH, NaCl concentration, rotational speed of the stirrer and electrode distance on reduction of color, COD and BOD were studied in detail. From the experimental results, 15 mA/cm{sup 2} current density, pH of 7, 1 g/l NaCl, 100 rpm, 28 deg, C temperature and 3 cm electrode distance were found to be optimum for maximum reduction of color, COD and BOD. The reduction of color, COD and BOD under the optimum condition were found to be 94%, 90% and 87% respectively. The electrode energy consumption was calculated and found to be varied from 10.1 to 12.9 kWh/m{sup 3} depending on the operating conditions. Under optimal operating condition such as 15 mA/cm{sup 2} current density, pH of 7, 1 g/l NaCl, 100 rpm, 28 deg, C temperature and 3 cm electrode distance, the operating cost was found to be 1.56 US $/m{sup 3}. The experimental results proved that the electrocoagulation is a suitable method for treating bleaching plant effluents for reuse.

  5. 40 CFR 98.270 - Definition of source category.

    Science.gov (United States)

    2010-07-01

    ... this section: (1) Chemical recovery furnaces at kraft and soda mills (including recovery furnaces that burn spent pulping liquor produced by both the kraft and semichemical process). (2) Chemical recovery... into paperboard products (e.g., containers), or operate coating and laminating processes. (b) The...

  6. Assessment of bleaching of K-feldspar grains

    International Nuclear Information System (INIS)

    Zhang Jiafu; Li Shenghua; Tso, M-Y.W.

    2001-01-01

    Based on the difference in the bleaching rate between IRSL and TL signals, a new method of assessing the bleaching of sedimentary feldspar is proposed. All measurements for De and the bleaching factor (normalized ratio of IRSL to TL) are carried out on the same grain. K-feldspar grains from two sediments, a marine and an alluvium, from Hong Kong were tested. Their bleaching factors indicate that bleaching of the marine sediment was not uniform, whereas the latter was relatively homogeneous. Furthermore, the relatively well-bleached grains in each sample were identified

  7. Bambu como matéria-prima para papel: IV - Estudos sôbre o emprêgo de cinco espécies de Bambusa,na produção de celulose sulfato Bamboo as a raw material for the pulp and paper industry: IV - Study of Bambusa tuldoides, B. textilis, B. ventricosa, B. malingensis and B. dissimulator in the production of kraft pulp

    Directory of Open Access Journals (Sweden)

    Anísio Azzini

    1971-05-01

    Full Text Available Com o presente trabalho, os autores dão continuidade aos estudos com que se procura determinar as características papeleiras das principais espécies de bambu com bom desenvolvimento nas condições ecológicas do Estado de São Paulo. Bambusa tuldoides, B. textilis, B. ventricosa, B. malingensis e B. dissimulator foram estudadas levando-se em consideração as seguintes variáveis: dimensões dos colmos, densidade básica, análise micrométrica das fibras, rendimento em celulose sulfato (Kraft e características físico-mecânicas das pastas produzidas. As densidades básicas médias calculadas para as espécies em estudo não apresentaram muita variação, com valores extremos de 0,62 e 0,78. Relativamente ao comprimento médio das fibras, as espécies de bambu estudadas mostraram ocupar uma posição intermediária entre as resinosas e as principais espécies arbóreas folhosas utilizadas pela indústria de papel. Os rendimentos médios em celulose sulfato, considerando cinco repetições, foram de 43,75% para B. textilis, 42,53% para B. tuldoides, 41,74% para B. ventricosa, 36,57% para B. dissimulator e 35,82% para B. malingensis, com número de permanganato variando de 18,37 a 17,03. Análise estatística dos dados de resistência do papel demonstrou que B. dissimulator, com exceção do índice de rasgo, apresentou maiores valores que as demais espécies em estudo.Five bamboo species, very similar in the agronomic features, were studied in the production of kraft pulp. All of them have culms with about 9 m in height, 4-5 cm in diameter and weight of 4-5 kg, growing very well in the soil and climate conditions of São Paulo State. Determinations of the basic density of culms and dimension of fibres were made. Chips were obtained mechanically and the cookings were made by the sulfate process at 160°C for l hour, using 14% Na(20 and 25% sul-phidity. Bambusa textilis and B. tuldoides which yielded, respectively 43.75% and 42.53% of

  8. Characterization of endo-β-mannanase from Enterobacter ludwigii MY271 and application in pulp industry.

    Science.gov (United States)

    Yang, Miao; Cai, Jun; Wang, Changgao; Du, Xin; Lin, Jianguo

    2017-01-01

    β-Mannanases are the second most important enzymes for the hydrolysis of hemicelluloses. An endo-β-mannanase from Enterobacter ludwigii MY271 was purified at 11.7 ± 0.2-fold to homogeneity with a final recovery of 15.2 ± 0.2 %. Using purified β-mannanase protein and SDS-PAGE, the molecular mass was found to be 43.16 kDa. The optimal pH and temperature of the enzyme was found to be 7.0 and 55 °C, respectively. The β-mannanase activity was stable over a broad pH range of pH 2.0-10.0. In addition, the purified enzyme was highly activated by several metal ions and chemical reagents, such as Mg 2+ , L-cysteine, glutathione (GSH) and β-mercaptoethanol. Whereas the enzyme was strongly inhibited by Hg 2+ , Cu 2+ , N-bromosuccinimide (NBS), 1-ethyl-3-(3-dimethyl-amino-propyl)-carbodiimide (EDC), phenylmethanesulfonyl fluoride (PMSF), and sodium dodecyl sulfate (SDS). The β-mannanase was highly active towards glucomannan, and showed endo-activity by producing a mixture of oligosaccharides. Moreover, the enzyme displayed a classical endo-type mode on mannooligosaccharides. The β-mannanase coupled with xylanase significantly improved the brightness of kraft pulp, whereas it has no remarkable effect on the tensile strength of the pulp. Our functional studies of the purified β-mannanase indicate that the enzyme is beneficial to industrial applications, in particular, biotechnological processes, such as food, feed and pulp industry.

  9. Use of an expert system for energy cost calculations in the pulp and paper industry

    International Nuclear Information System (INIS)

    Viinikainen, S.; Malinen, H.

    1991-12-01

    In this paper, an application for the calculation of energy prices and product energy costs in the pulp and paper industry by using the Xi Plus expert system is presented. The use of expert systems in the energy field and also the Xi Plus expert system and its general features are also discussed. The application has been made after collecting data from several sources. It runs in an IBM AT compatible microcomputer therefore being easily used in mills. The name of the application is PRODUCT ENERGY COST. It has a three level structure: the mill level, the department level and the main equipment level. Currently, the mill level and, in the energy production area, the department level (power plant) and the equipment level (boilers, turbines) are used. The application consists of four knowledge base groups. Altogether there are 52 separate knowledge bases having 534 rules or demons. The knowledge base groups are: BASIC DATA, ENERGY USE, ENERGY PRODUCTION and ENERGY COSTS. The application can be used for various heat and electrical energy price calculations or for energy cost calculations for different pulp and paper products. In this study, the energy prices for kraft pulp, TMP, newsprint and fine paper in different operating conditions and the associated energy costs of the products are calculated. Also, in some cases a sensitivity analysis is done. The expert system is quite suitable for this type of calculation and the method could be further developed for specific industrial needs, e.g. to enhance the energy management systems

  10. Optical transparency of paper as a function of moisture content with applications to moisture measurement.

    Science.gov (United States)

    Forughi, A F; Green, S I; Stoeber, B

    2016-02-01

    Accurate measurement of the moisture content of paper is essential in papermaking and is also important in some paper-based microfluidic devices. Traditional measurement techniques provide very limited spatiotemporal resolution and working range. This article presents a novel method for moisture content measurement whose operating principle is the strong correlation between the optical transparency of paper and its moisture content. Spectrographic and microscopic measurement techniques were employed to characterize the relation of moisture content and relative transparency of four types of paper: hardwood chemi-thermomechanical pulp paper, Northern bleached softwood kraft paper, unbleached softwood kraft paper, and General Electric(®) Whatman™ grade 1 chromatography paper. It was found that for all paper types, the paper transparency increased monotonically with the moisture content (as the ratio of the mass-of-water to the mass-of-dry-paper increased from 0% to 120%). This significant increase in relative transparency occurred due to the refractive index matching role of water in wet paper. It is further shown that mechanical loading of the paper has little impact on the relative transparency, for loadings that would be typical on a paper machine. The results of two transient water absorption experiments are presented that show the utility and accuracy of the technique.

  11. Kraft cooking of gamma irradiated wood, (1). Effect of alcohol additives on pre-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Inaba, M; Meshitsuka, G; Nakano, J [Tokyo Univ. (Japan). Faculty of Agriculture

    1979-12-01

    Studies have been made of kraft cooking of gamma irradiated wood. Beech (Fagus crenata Blume) wood meal suspended in aqueous alkaline alcohol was irradiated up to 1.5 KGy (0.15 Mrad) with gamma rays from a Co-60 source in the presence or absence of oxygen. The irradiated wood meals were washed thoroughly with fresh water, air dried and cooked under the ordinary cooking conditions. The results are summarized as follows: (1) Pre-irradiation in aqueous alkali have negligible effect on kraft cooking. (2) In the case of ethanol addition (50 g/l), pre-irradiation in vacuo shows acceleration of delignification and stabilization of carbohydrates during kraft cooking. Cooked yield gain by pre-irradiation was about 1.2 in all, over the range of delignification from 80 to 90%. Aqueous ethanol without alkali also shows positive but smaller effect than that with alkali. (3) Propanol, iso-propanol and butanol show positive but smaller effects than ethanol. However, methanol does not show any positive effect. (4) Irradiation in the presence of oxygen does not show any attractive effect on kraft cooking.

  12. Perbandingan intensitas warna CPO dengan menggunakan Bleaching Earth (BE) dan Spent Bleaching Earth (SBE) di PT. SMART Tbk.

    OpenAIRE

    Aritonang, Dwi Christina

    2016-01-01

    Comparative studies have been conducted on the effect of bleaching earth quality bleachibility power on CPO (crude palm oil). by using the tool Lovibond Tintometer model of F in PT Smart Tbk Medan – Belawan.From experiments obtained initial color with the CPO 20R - 20Y after addition Bleaching Earth and spent bleaching earth with the CPO each - each 10,2R - 20Y and 17.3R - 20Y . The results showed that purification using Bleaching Earth better than the purification of Spent Bleaching Earh ...

  13. Coral reef bleaching: ecological perspectives

    Science.gov (United States)

    Glynn, P. W.

    1993-03-01

    Coral reef bleaching, the whitening of diverse invertebrate taxa, results from the loss of symbiotic zooxanthellae and/or a reduction in photosynthetic pigment concentrations in zooxanthellae residing within the gastrodermal tissues of host animals. Of particular concern are the consequences of bleaching of large numbers of reef-building scleractinian corals and hydrocorals. Published records of coral reef bleaching events from 1870 to the present suggest that the frequency (60 major events from 1979 to 1990), scale (co-occurrence in many coral reef regions and often over the bathymetric depth range of corals) and severity (>95% mortality in some areas) of recent bleaching disturbances are unprecedented in the scientific literature. The causes of small scale, isolated bleaching events can often be explained by particular stressors (e.g., temperature, salinity, light, sedimentation, aerial exposure and pollutants), but attempts to explain large scale bleaching events in terms of possible global change (e.g., greenhouse warming, increased UV radiation flux, deteriorating ecosystem health, or some combination of the above) have not been convincing. Attempts to relate the severity and extent of large scale coral reef bleaching events to particular causes have been hampered by a lack of (a) standardized methods to assess bleaching and (b) continuous, long-term data bases of environmental conditions over the periods of interest. An effort must be made to understand the impact of bleaching on the remainder of the reef community and the long-term effects on competition, predation, symbioses, bioerosion and substrate condition, all factors that can influence coral recruitment and reef recovery. If projected rates of sea warming are realized by mid to late AD 2000, i.e. a 2°C increase in high latitude coral seas, the upper thermal tolerance limits of many reef-building corals could be exceeded. Present evidence suggests that many corals would be unable to adapt

  14. The energy efficiency partnership - Kraft General Foods and Boston Edison Company

    International Nuclear Information System (INIS)

    Crowley, J.C.; Donoghue, J.P.

    1993-01-01

    During the past twenty years, inordinate shifts in the supply and demand of energy have forced both electric utility companies and their customers to investigate new and innovative ways to satisfy the ever increasing demand for electricity. The Energy Efficiency Partnership, developed between Kraft General Foods and Boston Edison Company, presents an exemplary study of how two corporate giants creatively solved the problem of uncontrolled energy costs and its positive effect on the overall operations of Kraft General Foods, Framingham. But the Energy Efficiency Partnership did more than reduce energy costs, it provided benefits to all parties on the playing field. To understand its significance, a review of the partnership's history is paramount. The first official announcement of the Energy Efficiency Partnership was made on April 9, 1990. Framingham, MA, The Commonwealth of Massachusetts Kraft General Foods Framingham, and Boston Edison Company have joined forces in a $3.6 million dollar energy partnership that will help keep 250 industrial jobs in Massachusetts and could lead to the future expansion of the international food company's Framingham facility

  15. Applications of radioactive tracers in the study of throughflow chemical reactors. XIII

    International Nuclear Information System (INIS)

    Thyn, J.; Pechlak, B.; Holoubek, I.

    1981-01-01

    Pulse responses were measured of the first four bleaching stages of the CEHDED bleaching plant producing paper pulp and of five stages of the CEDED bleaching plant producing dissolving pulp. The transition characteristics of individual stages and of the whole unit comprising stages I-II, I-III and I to V or VI were calculated. The method is described of using measured data for the prediction of transition characteristics for outputs other than for which the pulse responses have been measured and the use of pulse response data is demonstrated for the evaluation of paper pulps (based on chlorine consumption or variations of the kappa number in the first chlorination degree) or for the evaluation of dissolving pulps on the basis of ''viscosity changes'm in the fourth stage (i.e., in hypochlorite bleaching). (author)

  16. Coral bleaching independent of photosynthetic activity.

    Science.gov (United States)

    Tolleter, Dimitri; Seneca, François O; DeNofrio, Jan C; Krediet, Cory J; Palumbi, Stephen R; Pringle, John R; Grossman, Arthur R

    2013-09-23

    The global decline of reef-building corals is due in part to the loss of algal symbionts, or "bleaching," during the increasingly frequent periods of high seawater temperatures. During bleaching, endosymbiotic dinoflagellate algae (Symbiodinium spp.) either are lost from the animal tissue or lose their photosynthetic pigments, resulting in host mortality if the Symbiodinium populations fail to recover. The >1,000 studies of the causes of heat-induced bleaching have focused overwhelmingly on the consequences of damage to algal photosynthetic processes, and the prevailing model for bleaching invokes a light-dependent generation of toxic reactive oxygen species (ROS) by heat-damaged chloroplasts as the primary trigger. However, the precise mechanisms of bleaching remain unknown, and there is evidence for involvement of multiple cellular processes. In this study, we asked the simple question of whether bleaching can be triggered by heat in the dark, in the absence of photosynthetically derived ROS. We used both the sea anemone model system Aiptasia and several species of reef-building corals to demonstrate that symbiont loss can occur rapidly during heat stress in complete darkness. Furthermore, we observed damage to the photosynthetic apparatus under these conditions in both Aiptasia endosymbionts and cultured Symbiodinium. These results do not directly contradict the view that light-stimulated ROS production is important in bleaching, but they do show that there must be another pathway leading to bleaching. Elucidation of this pathway should help to clarify bleaching mechanisms under the more usual conditions of heat stress in the light. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Recyclable zein-coated kraft paper and linerboard

    Science.gov (United States)

    Nicholas Parris; Marguerite Sykes; Leland C. Dickey; Jack L. Wiles; Thomas J. Urbanik; Peter H. Cooke

    2002-01-01

    Recyclability of kraft paper and linerboard coated with commercial zein and paraffin wax or a zein-lipid mixture was evaluated using conventional recycling processes. Zein, an alcohol-soluble protein from corn, exhibits both grease and water vapor barrier properties. Strength properties, grease resistance, and water vapor barrier proper-ties were measured on handsheets...

  18. Reef corals bleach to resist stress.

    Science.gov (United States)

    Obura, David O

    2009-02-01

    A rationale is presented here for a primary role of bleaching in regulation of the coral-zooxanthellae symbiosis under conditions of stress. Corals and zooxanthellae have fundamentally different metabolic rates, requiring active homeostasis to limit zooxanthellae production and manage translocated products to maintain the symbiosis. The control processes for homeostasis are compromised by environmental stress, resulting in metabolic imbalance between the symbionts. For the coral-zooxanthella symbiosis the most direct way to minimize metabolic imbalance under stress is to reduce photosynthetic production by zooxanthellae. Two mechanisms have been demonstrated that do this: reduction of the chlorophyll concentration in individual zooxanthellae and reduction of the relative biomass of zooxanthellae. Both mechanisms result in visual whitening of the coral, termed bleaching. Arguments are presented here that bleaching provides the final control to minimize physiological damage from stress as an adversity response to metabolic imbalance. As such, bleaching meets the requirements of a stress response syndrome/general adaptive mechanism that is sensitive to internal states rather than external parameters. Variation in bleaching responses among holobionts reflects genotypic and phenotypic differentiation, allowing evolutionary change by natural selection. Thus, reef corals bleach to resist stress, and thereby have some capacity to adapt to and survive change. The extreme thermal anomalies causing mass coral bleaching worldwide lie outside the reaction norms for most coral-zooxanthellae holobionts, revealing the limitations of bleaching as a control mechanism.

  19. BLEACHING NEPTUNE BALLS

    Directory of Open Access Journals (Sweden)

    BONET Maria Angeles

    2014-05-01

    Full Text Available Posidonia Oceanic is a seaweed from Mediterranean Sea and it is more concentrated at the Balerian SEA. This implies the Valencian Community also. It forms vaste underwater meadows in the sea and are part of the Mediterranean ecosystem. It is a sea-grass specie with fruits and flowers. Leaves are ribbon-like and they grow in winter and at the end of summer some of them are separated and arrive to some sea line. Fuit is separated and can floate, it is known as “the olive of the sea” mainly in Italy, or as the Neptune Balls. As it can be used in different fields, it is is being studied in order ro have the precitice tests. Some authors have reported the manufacturing of fully bio-based comites with a gluten matrix by hot-press molding. And it has been considered as an effective insulator for building industry or even though to determine the presence of mercure in the Mediterranean sea some years ago. As many applications can be designed from that fibers, it has been considered to be bleached in order to used them in fashionable products. Consequently, its original brown color is not the most suitable one and it should be bleached as many other cellulosic fibers. The aim of this paper is to bleache neptune balls however, the inner fibers were not accessible at all and it implied not to bleach the inner fibers in the neptune ball. Further studiesd will consider bleaching the individualized fibers.

  20. Sugar cane leaf: a potential raw material for cheap grades of paper and board

    Energy Technology Data Exchange (ETDEWEB)

    Tiwary, K. N.; Kulkarni, A. Y.

    1980-03-15

    About 6 to 7 million tons of sugar cane leaves are available per year as agricultural residue and can be utilized for manufacture of cheap grades of paper and board. An unbleached yield of 56% could be obtained using 10% NaOH at a temperature of 170/sup 0/C with a bath ratio of 1 to 4 and cooking time of 10 min. Sulfate pulping with equivalent conditions gave a bleached pulp with comparatively higher brightness values, other properties remaining almost same. Bleaching of 10% soda pulp with 10 and 12% chlorine have given 42 and 40% yields at 71 to 72 and 77 to 78% Elrepho brightness, respectively. In case of 9% sulfate pulp the yields are 36 to 37% at 77 to 79% brightness when bleached with the same sequence as above with 10 to 10.5% chlorine. The pulps are strong for preparation of cheap grades of bleached as well as unbleached varieties of paper. Double fold and tear are however medium to low and hence need long fibered pulp blending to improve these characteristics.

  1. Immune defenses of healthy, bleached and diseased Montastraea faveolata during a natural bleaching event.

    Science.gov (United States)

    Mydlarz, Laura D; Couch, Courtney S; Weil, Ernesto; Smith, Garriet; Harvell, C Drew

    2009-11-16

    One prominent hypothesis regarding climate change and scleractinian corals is that thermal stress compromises immune competence. To test this hypothesis we tracked how the immune defenses of bleached, apparently healthy and yellow band disease (YBD) diseased Montastraea faveolata colonies varied with natural thermal stress in southwestern Puerto Rico. Colonies were monitored for 21 mo from the peak of the bleaching event in October 2005 to August 2007. Since sea surface temperature was significantly higher in summer and fall 2005 than 2006, year of collection was used as a proxy for temperature stress, and colony fragments collected in 2005 were compared with those collected in 2006. Mortality rate was high (43% overall) and all colonies (except one) either died or became infected with YBD by August 2007. YBD-infected tissue did not bleach (i.e. expel zooxanthellae) during the 2005 bleaching event, even when healthy tissue of these colonies bleached. Immune activity was assayed by measuring prophenoloxidase (PPO), peroxidase (POX), lysozyme-like (LYS) and antibacterial (AB) activity. Immune activity was variable between all coral samples, but there was a significant elevation of PPO activity in bleached colonies collected in 2005 relative to apparently healthy and YBD-diseased corals in 2006. In YBD-diseased colonies, LYS and AB activity were elevated in both healthy and infected tissue, indicating a systemic response; activity levels in these colonies were higher compared to those that appeared healthy. In both these immune parameters, there was a trend for suppression of activity in corals that were bleached in 2005. These data, while complicated by between-genet variability, illustrate the complex interaction between disease and temperature stress on immune function.

  2. APROVEITAMENTO DA CASCA DO COCO-VERDE (Cocos nucifera L. PARA PRODUÇÃO DE POLPA CELULÓSICA

    Directory of Open Access Journals (Sweden)

    Mahalia Sojo Cardoso

    2016-01-01

    Full Text Available The coconut husk is a residue from consumption of coconut water. In coastal cities this residue has already become a big problem, because it is difficult to decompose. The present study aimed to evaluate the husk of the coconut ( Cocos nucifera L. for production of kraft pulp. The raw material was characterized and had its basic density, chemical composition, fiber size and proportion of anatomical elements analyzed. Pulping tests were conducted and one of them was chosen for repetition. In each pulping the alkali charge was variable in order to prepare an alkaline curve. The results from the pulping process show high levels of kappa number, low yields and low rejects content. The following characteristics of the material, low basic density (0.128 g/cm ³, high amount of extractives (33.68% and low proportion of fibers (22.11%, corroborate to these results. Thus, the production of pulp from the coconut husk by the kraft process, it is not an alternative technically feasible.

  3. The efficacy of laser-assisted in-office bleaching and home bleaching on sound and demineralized enamel

    Science.gov (United States)

    Akbari, Majid; Mohammadpour, Sakineh

    2015-01-01

    Aims: This study investigated the effectiveness of laser-assisted in-office bleaching and home-bleaching in sound and demineralized enamel. Materials and Methods: The sample consisted of 120 freshly-extracted bovine incisors. Half of the specimens were stored in a demineralizing solution to induce white spot lesions. Following exposure to a tea solution for 7.5 days, the specimens were randomly assigned to 4 groups of 30 according to the type of enamel and the bleaching procedure employed. Groups 1 and 2 consisted of demineralized teeth subjected to in-office bleaching and home bleaching, whereas in groups 3 and 4, sound teeth were subjected to in-office and home bleaching, respectively. A diode laser (810 nm, 2 W, continuous wave, four times for 15 seconds each) was employed for assisting the in-office process. The color of the specimens was measured before (T1) and after (T2) staining and during (T3) and after (T4) the bleaching procedures using a spectrophotometer. The color change (ΔE) between different treatments stages was compared among the groups. Results: There were significant differences in the color change between T2 and T3 (ΔE T2–T3) and T2 and T4 (ΔE T2–T4) stages among the study groups (pbleaching (group 1) as compared to the other groups (Pbleaching could provide faster and greater whitening effect than home bleaching on stained demineralized enamel, but both procedures produced comparable results on sound teeth. PMID:26877590

  4. Microtensile bond strength of enamel after bleaching.

    Science.gov (United States)

    Lago, Andrea Dias Neves; Garone-Netto, Narciso

    2013-01-01

    To evaluate the bond strength of a composite resin to the bovine enamel bleached with 35% hydrogen peroxide. It was used an etching-and-rinse adhesive system employed immediately, 7 and 14 days after the bleaching. Twenty bovine teeth were randomly distributed into 4 groups (n = 5), 3 experimental and 1 control. G1: Unbleached + restoration 14 days after storage in artificial saliva (control); G2: Bleached + restoration immediately after bleaching; G3: Bleached + restoration 7 days after bleaching; G4: Bleached + restoration 14 days after bleaching. Their buccal enamel surfaces were flattened, and a 25 mm² (5 × 5 mm) area from each one of these regions was outlined so as to standardize the experimental region. Universal hybrid composite resin Filtek™Z350 was inserted into four layers of 1 mm each and photo-activated. The bond strength was quantitatively evaluated by a microtensile test (1.0 mm/min) 24 h after the restorative procedures. The failure mode was assessed through scanning electron microscopy (SEM). There was a significant reduction in the bond strength of the restored teeth immediately after the bleaching (G2). There were no significant differences in enamel bond strength between groups G1, G3, and G4. There was a predominance of adhesive and mixed (cohesive + adhesive) failure in all groups. The 7-day-period after the end of the bleaching with 35% hydrogen peroxide was enough to achieve the appropriate values of bond strength to the enamel.

  5. Radiation coloration and bleaching of glass

    International Nuclear Information System (INIS)

    Treadaway, M.J.; Passenheim, B.C.; Kitterer, B.D.; Schall, P.

    1976-01-01

    The results of an investigation of the bleaching of radiation-induced darkening in ten Schott optical glasses is presented. Measurements were made at several temperatures from 160K to 340K for times from 5 msec to 500 hours after exposure. The theory of processes distributed in activation energies has been used to formulate a model which explains the time and temperature dependence of the bleaching. Analysis of the bleaching results in terms of this model has yielded the activation energy distributions and ''frequency factors'' which govern the bleaching for each material

  6. Technical Report Cellulosic Based Black Liquor Gasification and Fuels Plant Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Fornetti, Micheal [Escanaba Paper Company, MI (United States); Freeman, Douglas [Escanaba Paper Company, MI (United States)

    2012-10-31

    The Cellulosic Based Black Liquor Gasification and Fuels Plant Project was developed to construct a black liquor to Methanol biorefinery in Escanaba, Michigan. The biorefinery was to be co-located at the existing pulp and paper mill, NewPage’s Escanaba Paper Mill and when in full operation would: • Generate renewable energy for Escanaba Paper Mill • Produce Methanol for transportation fuel of further refinement to Dimethyl Ether • Convert black liquor to white liquor for pulping. Black liquor is a byproduct of the pulping process and as such is generated from abundant and renewable lignocellulosic biomass. The biorefinery would serve to validate the thermochemical pathway and economic models for black liquor gasification. It was a project goal to create a compelling new business model for the pulp and paper industry, and support the nation’s goal for increasing renewable fuels production and reducing its dependence on foreign oil. NewPage Corporation planned to replicate this facility at other NewPage Corporation mills after this first demonstration scale plant was operational and had proven technical and economic feasibility. An overview of the process begins with black liquor being generated in a traditional Kraft pulping process. The black liquor would then be gasified to produce synthesis gas, sodium carbonate and hydrogen sulfide. The synthesis gas is then cleaned with hydrogen sulfide and carbon dioxide removed, and fed into a Methanol reactor where the liquid product is made. The hydrogen sulfide is converted into polysulfide for use in the Kraft pulping process. Polysulfide is a known additive to the Kraft process that increases pulp yield. The sodium carbonate salts are converted to caustic soda in a traditional recausticizing process. The caustic soda is then part of the white liquor that is used in the Kraft pulping process. Cellulosic Based Black Liquor Gasification and Fuels Plant project set out to prove that black liquor gasification could

  7. Dental bleaching on teeth submitted to enamel microabrasion 30 years ago-a case report of patients' compliance during bleaching treatment.

    Science.gov (United States)

    Sundfeld, Daniel; Pavani, Caio Cesar; Schott, Timm Cornelius; Machado, Lucas Silveira; Pini, Núbia Inocêncya Pavesi; Bertoz, André Pinheiro de Magalhães; Sundfeld, Renato Herman

    2018-04-20

    The present dental bleaching case report describes a new method that precisely quantifies the daily wearing-times of the bleaching product by inserting a microsensor in the acetate custom tray. The bleaching efficacy was also discussed since the patient was previously submitted to enamel microabrasion. The patient was submitted to enamel microabrasion in 1987, and bleaching treatment was performed in 2005. In 2017, re-bleaching was executed using 10% peroxide carbamide. The electronic microsensor, TheraMon (TheraMon® microelectronic system; Sales Agency Gschladt, Hargelsberg, Austria), was embedded in the labial region of the upper and lower acetate trays to evaluate the wearing-times of the acetate trays/bleaching product. The patient was instructed to wear the tray for 6 to 8 h/day while sleeping. After 24 days of bleaching treatment, the data obtained from the TheraMon electronic devices was collected and interpreted. The patient did not entirely follow the bleaching treatment as recommended, as there was no evidence of use of the upper and lower trays for some days; additionally, the bleaching product was used for shorter and longer periods than was instructed. The TheraMon microeletronic device precisely measured the wearing-times of the acetate tray/bleaching product during the bleaching treatment. Teeth submitted to enamel microabrasion presented with a healthy clinical appearance after 30 years. Measuring the length and frequency of use of an acetate tray/bleaching product can be important to clinicians and patients for obtaining a controlled and adequate bleaching treatment.

  8. Structural, morphological, and thermal characterization of kraft lignin and its charcoals obtained at different heating rates

    Science.gov (United States)

    Rodrigues Brazil, Tayra; Nunes Costa, Rogeria; Massi, Marcos; Cerqueira Rezende, Mirabel

    2018-04-01

    Biomass is a renewable resource that is becoming more import due to environmental concerns and possible oil crisis. Thus, optimizing its use is a current challenge for many researchers. Lignin, which is a macromolecule with complex chemical structure, valuable physicochemical properties, and varied chemical composition, is available in large quantities in pulp and paper companies. The objective of this work is the physicochemical characterization of two Kraft lignin samples with different purities, and the study of its thermal conversion into charcoal. The lignin characterization was based on chemical, TGA, DSC, FT-IR, particle sizes, and FEG-SEM analyses. These analyses show that the lignins are mainly composed of guaiacyl and syringyl units, with residues of 30–36 wt.%, in inert atmosphere, depending on the lignin purity. From these results, the more purified lignin with higher carbon yield (%C) was selected for charcoal production. The heat treatment (HT) for carbonization of lignin, at different times (90, 180, and 420 min), resulted in different %C (41–44 wt.%). Longer HT resulted in higher %C and in charcoals with smaller pore sizes. Nanopores (∼50 nm) are observed for the charcoal obtained with the longest HT.

  9. Side effects of external tooth bleaching

    DEFF Research Database (Denmark)

    Bruzell, E.M.; Pallesen, Ulla; Thoresen, N.R.

    2013-01-01

    Objective The study was performed to assess the risk of at-home and in-office bleaching procedures, and to recognise potential predictors for side effects. Design Multi-centre, questionnaire-based prospective study with follow-ups at around 14 days and around one year post-treatment. Setting...... General practices and university clinics during the years 2007‑2009 in Scandinavia. Subjects Patients with tooth bleaching as part of the treatment plan. Results The prevalence of experienced tooth sensitivity at first follow-up was independent of bleaching procedure (at-home = 50.3% [n = 143]; in...... attributed to the bleaching treatment in the at-home and in-office groups, respectively. Predictors for side effects were tooth sensitivity, surface loss and gingivitis when observed at inclusion. Treatment-related predictors were bleaching concentration and contact between tray and gingiva. Conclusions...

  10. Microtensile bond strength of enamel after bleaching

    Directory of Open Access Journals (Sweden)

    Andréa Dias Neves Lago

    2013-01-01

    Full Text Available Objective: To evaluate the bond strength of a composite resin to the bovine enamel bleached with 35% hydrogen peroxide. It was used an etching-and-rinse adhesive system employed immediately, 7 and 14 days after the bleaching. Materials and Methods: Twenty bovine teeth were randomly distributed into 4 groups (n = 5, 3 experimental and 1 control. G1: Unbleached + restoration 14 days after storage in artificial saliva (control; G2: Bleached + restoration immediately after bleaching; G3: Bleached + restoration 7 days after bleaching; G4: Bleached + restoration 14 days after bleaching. Their buccal enamel surfaces were flattened, and a 25 mm² (5 × 5 mm area from each one of these regions was outlined so as to standardize the experimental region. Universal hybrid composite resin Filtek™Z350 was inserted into four layers of 1 mm each and photo-activated. The bond strength was quantitatively evaluated by a microtensile test (1.0 mm/min 24 h after the restorative procedures. The failure mode was assessed through scanning electron microscopy (SEM. Results: There was a significant reduction in the bond strength of the restored teeth immediately after the bleaching (G2. There were no significant differences in enamel bond strength between groups G1, G3, and G4. There was a predominance of adhesive and mixed (cohesive + adhesive failure in all groups. Conclusion: The 7-day-period after the end of the bleaching with 35% hydrogen peroxide was enough to achieve the appropriate values of bond strength to the enamel.

  11. Don't bleach chaotic data

    International Nuclear Information System (INIS)

    Theiler, J.; Eubank, S.

    1993-01-01

    A common first step in time series signal analysis involves digitally filtering the data to remove linear correlations. The residual data is spectrally white (it is ''bleached''), but in principle retains the nonlinear structure of the original time series. It is well known that simple linear autocorrelation can give rise to spurious results in algorithms for estimating nonlinear invariants, such as fractal dimension and Lyapunov exponents. In theory, bleached data avoids these pitfalls. But in practice, bleaching obscures the underlying deterministic structure of a low-dimensional chaotic process. This appears to be a property of the chaos itself, since nonchaotic data are not similarly affected. The adverse effects of bleaching are demonstrated in a series of numerical experiments on known chaotic data. Some theoretical aspects are also discussed

  12. [Assessment of tooth bleaching efficacy with spectrophotometer].

    Science.gov (United States)

    Zhu, Wenhao; Liu, Chang; Pan, Jie

    2014-06-01

    To analyze the changes in CIE L*, a*, and b* at cervical, body, and incisal sites after tooth bleaching by using a spectrophotometer. Sixty-seven intact and healthy maxillary central incisors were in-vestigated. These incisors were darker than A3 according to the Vita Classical shade guide. The CIE tooth shade parameters L*, a*, and b* were simultaneously recorded at three tooth areas (cervical, body, and incisal) with a spectrophotometer before and after tooth bleaching (35%H2O2 coordinating with Beyond whitening accelerator irradiating). The shade dif-ferential (DeltaE) was calculated. ANOVA, paired t-test, and Pearson correlation analysis were used for data analysis. The efficacy rates of tooth bleaching were satisfactory, with 86.6%, 86.6%, and 85.1% in the cervical, body, and incisal sites, respectively. The average values of DeltaE were 5.09, 4.44, and 4.40 in the cervical, body, and incisal sites. Tooth bleaching significantly increased L* and significantly decreased a* and b* in all tooth areas (P spectrophotometer could objectively evaluate the whitening effect of tooth bleaching at the different tooth sites. The tooth bleaching system (35%H202 coordinating with Beyond whitening accelerator irradiating) exerts powerful bleaching actions in most of the tooth areas investigated. The order of tooth bleaching effectiveness is cervicalbody>incisal. Yellow coloration is decreased mainly at the cervical site, and brightness was increased mostly at theincisal site. The effectiveness of tooth bleaching increases as the baseline b* value increases.

  13. Radiation application for paper preservation: gamma irradiation at Eucalyptus pulp sheets

    International Nuclear Information System (INIS)

    Borrely, Sueli Ivone; Barbosa, Patricia S.M.; D'Almeida, Maria Luiza O.

    2009-01-01

    Ionizing radiation has been proposed in order to protect information and books that may be lost due to fungi and or insects infestation. In general restaurators are very worried about the maintenance of original properties of items to be treated. The selected technology must consider two points: type of biological contamination and contamination control. Fungi is one of the principal organism which grows well on papers. Once this infestation is installed on the paper it will signify spots, resistance loses and deterioration. The organisms feces introduces enzymes, organic acids and pigments to the contaminated material. Ionizing radiation from gamma sources were applied at laboratory sheets manufactured with commercial cellulose pulp. The subject of this present paper was to investigate the ideal radiation dose that is safe for keeping the paper quality. Laboratory sheets (75 g/m 2 ) were prepared in a TAPPI sheet former. Bleached sulphate Eucalyptus pulp, refined in laboratory PFI mill to 31 deg SR, was the raw material. The formed sheets were irradiated at IPEN's 60 Co Gammacell with 3 kGy up to 25 kGy. No significant changes were detected in paper samples irradiated up to 9 kGy. This is the radiation dose to be suggested. During irradiation the applied dose rate was 0.817 Gy/s. (author)

  14. Ground beetle populations near a kraft mill

    Energy Technology Data Exchange (ETDEWEB)

    Freitag, R.; Hastings, L.; Mercer, W.R.; Smith, A.

    1973-02-01

    Twenty species of ground beetles (Family Carabidae) and one species of carrion beetle (Family Silphidae) were collected in six stations east of a kraft paper mill in Thunder Bay, Ontario, from May to August, 1971. The beetle population decreased markedly towards the mill. There was no apparent statistical difference in size variation of specimens near the mill and those further away.

  15. Regeneration of irradiated optical fibres by photo-bleaching?

    International Nuclear Information System (INIS)

    Henschel, H.; Koehn, O.

    1999-01-01

    It is known that a light power between 0,1 and 20 μW caused bleaching of colour centres, which implies a reduction of induced loss. Older fibres especially those with a core made of undoped, low OH silica, experience tremendous photo-bleaching. Light of shorter wavelengths has a higher bleaching efficiency than that of longer wavelengths and same light intensity. The investigations have demonstrated that the injection of photo-bleaching light of shorter wavelength and higher intensity can distinctly decrease the radiation-induced loss of Ge-doped fibres, especially at low temperatures. Another possibility to apply photo-bleaching by short wavelength is to regenerate fibres that are permanently installed in radiation environments. Modern undoped multi-mode (MM) step index (Si), Ge-doped MM graded index (Gi) and Ge-doped single-mode (SM) fibres that had been irradiated were submitted to bleaching light. In this article it is shown how loss reduction and necessary bleaching time depend on wavelength and intensity of the bleaching light, on fibre length (bleaching time) and on radiation dose. These results are promising for the regeneration of optical fibres in facilities where the fibres cannot be replaced easily by new ones. (A.C.)

  16. Clinical and patient reported outcomes of bleaching effectiveness.

    Science.gov (United States)

    Klaric Sever, Eva; Budimir, Zrinka; Cerovac, Matea; Stambuk, Mario; Par, Matej; Negovetic Vranic, Dubravka; Tarle, Zrinka

    2018-01-01

    The objective of this study is to evaluate clinical and patient reported outcomes of different bleaching products. Thirty participants were randomly divided into three bleaching groups (n = 10). Bleaching was performed with high concentrations of hydrogen peroxide (HP) - Boost (40%) and Dash (30%), and with prefabricated splints Bite&White (6% HP). Tooth colour was measured before, immediately after, and 1 and 6 months after the bleaching by using classical shade guide and spectrophotometer. Tooth hypersensitivity was self-rated by patients on the Wong-Baker's face scale. Patient satisfaction was evaluated on a 7-point Likert-type scales that measured perceived performance and importance of different characteristics of bleaching treatment. All products were effective in teeth colour change (ΔE > 3.3), which was significantly higher for Boost (p = .016) and Dash (p = .024) than Bite&White treatment. Perception of hypersensitivity was the highest in Boost group, followed by Dash and Bite&White treatment. Most of the patients were satisfied with final tooth colour, length and comfort during treatment, but were dissatisfied with the stability of bleached tooth colour. Materials with the higher concentrations of bleaching agent demonstrated greater bleaching effectiveness than at-home bleaching product, but also a greater hypersensitivity. Lengthening the treatment process, but achieving a more stable tooth colour may improve the perceived value of a bleaching service.

  17. Coral bleaching response index: a new tool to standardize and compare susceptibility to thermal bleaching.

    Science.gov (United States)

    Swain, Timothy D; Vega-Perkins, Jesse B; Oestreich, William K; Triebold, Conrad; DuBois, Emily; Henss, Jillian; Baird, Andrew; Siple, Margaret; Backman, Vadim; Marcelino, Luisa

    2016-07-01

    As coral bleaching events become more frequent and intense, our ability to predict and mitigate future events depends upon our capacity to interpret patterns within previous episodes. Responses to thermal stress vary among coral species; however the diversity of coral assemblages, environmental conditions, assessment protocols, and severity criteria applied in the global effort to document bleaching patterns creates challenges for the development of a systemic metric of taxon-specific response. Here, we describe and validate a novel framework to standardize bleaching response records and estimate their measurement uncertainties. Taxon-specific bleaching and mortality records (2036) of 374 coral taxa (during 1982-2006) at 316 sites were standardized to average percent tissue area affected and a taxon-specific bleaching response index (taxon-BRI) was calculated by averaging taxon-specific response over all sites where a taxon was present. Differential bleaching among corals was widely variable (mean taxon-BRI = 25.06 ± 18.44%, ±SE). Coral response may differ because holobionts are biologically different (intrinsic factors), they were exposed to different environmental conditions (extrinsic factors), or inconsistencies in reporting (measurement uncertainty). We found that both extrinsic and intrinsic factors have comparable influence within a given site and event (60% and 40% of bleaching response variance of all records explained, respectively). However, when responses of individual taxa are averaged across sites to obtain taxon-BRI, differential response was primarily driven by intrinsic differences among taxa (65% of taxon-BRI variance explained), not conditions across sites (6% explained), nor measurement uncertainty (29% explained). Thus, taxon-BRI is a robust metric of intrinsic susceptibility of coral taxa. Taxon-BRI provides a broadly applicable framework for standardization and error estimation for disparate historical records and collection of novel

  18. ESTUDO DA ADIÇÃO DA LIGNINA KRAFT NAS PROPRIEDADES MECÂNICAS DOS BRIQUETES DE RESÍDUOS DA INDÚSTRIA MOVELEIRA

    Directory of Open Access Journals (Sweden)

    Adriana de Fátima Gomes Gouvêa

    2017-01-01

    Full Text Available In order to improve global effectiveness of energy production, a strategy is the model of bio-refineries in which all the components of biomass are totally used to produce a range of products with aggregated value. The kraft lignin is one of the products originated in the process of cellulose production that can be used in making densified products. The objective of this work was to evaluate the behavior of the addition of extracted kraft lignin of black kraft liquor in briquette manufactures with furniture industry waste, in the form of shavings and panel particles in different proportions. The briquettes were produced in laboratory briquetting, using the temperatures of 60, 75 and 90 o C. The pressing and cooling time was 5 minutes and pressure 68,9 x 10 5 N.m -2 (1000 PSI. The briquette quality was evaluated through determining the mechanical properties. The kraft lignin in adequate proportions and temperature showed advantages in the increase of resistance and the durability of the briquettes. The kraft lignin presented advantages such as agglutinative in briquette productions from wood waste at a pressing temperature of 90 o C with addition of 20% of kraft lignin, and at pressing temperatures of 60 and 75 o C at a proportion of addition of 40 and 60% of kraft lignin to wood waste, respectively.

  19. Identifying well-bleached quartz using the different bleaching rates of quartz and feldspar luminescence signals

    DEFF Research Database (Denmark)

    Murray, A.S.; Thomsen, Kristina Jørkov; Masuda, N.

    2012-01-01

    When dating older sedimentary deposits using quartz, there are no unambiguous methods for identifying the presence of incomplete bleaching. Current statistical analysis of dose distributions depends entirely on the assumption that incomplete bleaching and mixing are the main causes of any excess...... dispersion in the distribution; the only existing way to test this assumption is using independent age control. Here we suggest a new approach to this question, based on the differential bleaching rates of quartz and feldspar luminescence signals. We first present data that confirm the differences...... in relative bleaching rates of quartz optically stimulated luminescence (OSL) and feldspar luminescence stimulated at 50 °C by infrared light (IR50) and feldspar luminescence stimulated at 290 °C by infrared light after a stimulation at 50 °C (pIRIR290), and use recently deposited samples to determine...

  20. Mass coral bleaching in the northern Persian Gulf, 2012

    Directory of Open Access Journals (Sweden)

    Javid Kavousi

    2014-09-01

    Full Text Available Coral bleaching events due to elevated temperatures are increasing in both frequency and magnitude worldwide. Mass bleaching was recorded at five sites in the northern Persian Gulf during August and September 2012. Based on available seawater temperature data from field, satellite and previous studies, we suggest that the coral bleaching threshold temperature in the northern Persian Gulf is between 33.5 and 34°C, which is about 1.5 to 2.5°C lower than that in the southern part. To assess the bleaching effects, coral genera counted during 60-minute dives were categorized into four groups including healthy, slightly bleached ( 50% bleached tissue and fully bleached colonies. The anomalously high sea surface temperature resulted in massive coral bleaching (~84% coral colonies affected. Acropora spp. colonies, which are known as the most vulnerable corals to thermal stress, were less affected by the bleaching than massive corals, such as Porites, which are among the most thermo-tolerant corals. Turbid waters, suggested as coral refugia against global warming, did not protect corals in this study since most affected corals were found in the most turbid waters. The 2012 bleaching in the northern Persian Gulf was relatively strong from the viewpoint of coral bleaching severity. Long-term monitoring is needed to understand the actual consequences of the bleaching event on the coral reefs and communities.

  1. Study on Bleaching Technology of Cotton Fabric with Sodium Percarbonate

    OpenAIRE

    Li Zhi; Wang Yanling; Wang Zhichao

    2016-01-01

    Bleach cotton fabric with sodium percarbonate solution. Analyse of the effect of the concentration of sodium percarbonate solution, bleaching time, bleaching temperature and the light radiation on the bleaching effect of fabric.The result shows that increasing concentrations of percarbonate,increasing the bleaching time , raising the bleaching temperature and the UV irradiation may whiten the cotton fabric.The most suitable conditions for the bleaching process is concentration of sodium perca...

  2. Coral bleaching at Little Cayman, Cayman Islands 2009

    Science.gov (United States)

    van Hooidonk, Ruben J.; Manzello, Derek P.; Moye, Jessica; Brandt, Marilyn E.; Hendee, James C.; McCoy, Croy; Manfrino, Carrie

    2012-06-01

    The global rise in sea temperature through anthropogenic climate change is affecting coral reef ecosystems through a phenomenon known as coral bleaching; that is, the whitening of corals due to the loss of the symbiotic zooxanthellae which impart corals with their characteristic vivid coloration. We describe aspects of the most prevalent episode of coral bleaching ever recorded at Little Cayman, Cayman Islands, during the fall of 2009. The most susceptible corals were found to be, in order, Siderastrea siderea, Montastraea annularis, and Montastraea faveolata, while Diplora strigosa and Agaricia spp. were less so, yet still showed considerable bleaching prevalence and severity. Those found to be least susceptible were Porites porites, Porites astreoides, and Montastraea cavernosa. These observations and other reported observations of coral bleaching, together with 29 years (1982-2010) of satellite-derived sea surface temperatures, were used to optimize bleaching predictions at this location. To do this a Degree Heating Weeks (DHW) and Peirce Skill Score (PSS) analysis was employed to calculate a local bleaching threshold above which bleaching was expected to occur. A threshold of 4.2 DHW had the highest skill, with a PSS of 0.70. The method outlined here could be applied to other regions to find the optimal bleaching threshold and improve bleaching predictions.

  3. Mass coral bleaching in 2010 in the southern Caribbean.

    Science.gov (United States)

    Alemu I, Jahson Berhane; Clement, Ysharda

    2014-01-01

    Ocean temperatures are increasing globally and the Caribbean is no exception. An extreme ocean warming event in 2010 placed Tobago's coral reefs under severe stress resulting in widespread coral bleaching and threatening the livelihoods that rely on them. The bleaching response of four reef building taxa was monitored over a six month period across three major reefs systems in Tobago. By identifying taxa resilient to bleaching we propose to assist local coral reef managers in the decision making process to cope with mass bleaching events. The bleaching signal (length of exposure to high ocean temperatures) varied widely between the Atlantic and Caribbean reefs, but regardless of this variation most taxa bleached. Colpophyllia natans, Montastraea faveolata and Siderastrea siderea were considered the most bleaching vulnerable taxa. Interestingly, reefs with the highest coral cover showed the greatest decline reef building taxa, and conversely, reefs with the lowest coral cover showed the most bleaching but lowest change in coral cover with little algal overgrowth post-bleaching.

  4. Mass Coral Bleaching in 2010 in the Southern Caribbean

    Science.gov (United States)

    Alemu I, Jahson Berhane; Clement, Ysharda

    2014-01-01

    Ocean temperatures are increasing globally and the Caribbean is no exception. An extreme ocean warming event in 2010 placed Tobago's coral reefs under severe stress resulting in widespread coral bleaching and threatening the livelihoods that rely on them. The bleaching response of four reef building taxa was monitored over a six month period across three major reefs systems in Tobago. By identifying taxa resilient to bleaching we propose to assist local coral reef managers in the decision making process to cope with mass bleaching events. The bleaching signal (length of exposure to high ocean temperatures) varied widely between the Atlantic and Caribbean reefs, but regardless of this variation most taxa bleached. Colpophyllia natans, Montastraea faveolata and Siderastrea siderea were considered the most bleaching vulnerable taxa. Interestingly, reefs with the highest coral cover showed the greatest decline reef building taxa, and conversely, reefs with the lowest coral cover showed the most bleaching but lowest change in coral cover with little algal overgrowth post-bleaching. PMID:24400078

  5. Antraquinona e surfactante para otimizaçao do processo Kraft com Pinus Spp.

    OpenAIRE

    Mocelin, Ezequiel Zatoni

    2013-01-01

    A madeira de Pinus é atualmente a matéria-prima mais utilizada na obtenção de fibras longas para papel, juntamente com o processo Kraft pela sua versatilidade e por produzir fibras com boa resistência. As atuais perspectivas florestais apontam para uma escassez da madeira de Pinus para os diversos fins, seja para madeira processada, seja para celulose e papel. O processo Kraft tem como desvantagem o baixo rendimento em celulose, devido à solubilização não somente da lignina como também parte ...

  6. Global warming and recurrent mass bleaching of corals

    Science.gov (United States)

    Hughes, Terry P.; Kerry, James T.; Álvarez-Noriega, Mariana; Álvarez-Romero, Jorge G.; Anderson, Kristen D.; Baird, Andrew H.; Babcock, Russell C.; Beger, Maria; Bellwood, David R.; Berkelmans, Ray; Bridge, Tom C.; Butler, Ian R.; Byrne, Maria; Cantin, Neal E.; Comeau, Steeve; Connolly, Sean R.; Cumming, Graeme S.; Dalton, Steven J.; Diaz-Pulido, Guillermo; Eakin, C. Mark; Figueira, Will F.; Gilmour, James P.; Harrison, Hugo B.; Heron, Scott F.; Hoey, Andrew S.; Hobbs, Jean-Paul A.; Hoogenboom, Mia O.; Kennedy, Emma V.; Kuo, Chao-Yang; Lough, Janice M.; Lowe, Ryan J.; Liu, Gang; McCulloch, Malcolm T.; Malcolm, Hamish A.; McWilliam, Michael J.; Pandolfi, John M.; Pears, Rachel J.; Pratchett, Morgan S.; Schoepf, Verena; Simpson, Tristan; Skirving, William J.; Sommer, Brigitte; Torda, Gergely; Wachenfeld, David R.; Willis, Bette L.; Wilson, Shaun K.

    2017-03-01

    During 2015-2016, record temperatures triggered a pan-tropical episode of coral bleaching, the third global-scale event since mass bleaching was first documented in the 1980s. Here we examine how and why the severity of recurrent major bleaching events has varied at multiple scales, using aerial and underwater surveys of Australian reefs combined with satellite-derived sea surface temperatures. The distinctive geographic footprints of recurrent bleaching on the Great Barrier Reef in 1998, 2002 and 2016 were determined by the spatial pattern of sea temperatures in each year. Water quality and fishing pressure had minimal effect on the unprecedented bleaching in 2016, suggesting that local protection of reefs affords little or no resistance to extreme heat. Similarly, past exposure to bleaching in 1998 and 2002 did not lessen the severity of bleaching in 2016. Consequently, immediate global action to curb future warming is essential to secure a future for coral reefs.

  7. Bleaching and recovery of a phototrophic bioeroding sponge

    Science.gov (United States)

    Marlow, Joseph; Davy, Simon K.; Shaffer, Megan; Haris, Abdul; Bell, James J.

    2018-06-01

    In the Wakatobi region of Indonesia, a prolonged period of elevated water temperature in 2016 caused extensive coral bleaching and mortality. Unusually, bleaching was also observed in the bioeroding sponge Cliona aff. viridis, with affected sponges expelling 99% of their Symbiodinium. Bleaching surveys of C. aff. viridis were conducted 6 weeks apart, coinciding with a 0.8 °C drop in water temperature. Over this period, bleaching prevalence dropped from 73.9% (± 9.9 SE) to 25.7% (± 5.8 SE), and bleaching severity dropped from 25.95% (± 4.5 SE) to 11.54% (± 1.9 SE) of sponge tissue. Over the same period, monitored bleached sponges showed an 81% drop in bleaching severity, but also a 13% reduction in overall sponge size. Our results show that while the clionaid- Symbiodinium relationship is susceptible to break down under thermal stress, rapid recovery can occur, although incurring some partial host mortality.

  8. Global warming and recurrent mass bleaching of corals.

    Science.gov (United States)

    Hughes, Terry P; Kerry, James T; Álvarez-Noriega, Mariana; Álvarez-Romero, Jorge G; Anderson, Kristen D; Baird, Andrew H; Babcock, Russell C; Beger, Maria; Bellwood, David R; Berkelmans, Ray; Bridge, Tom C; Butler, Ian R; Byrne, Maria; Cantin, Neal E; Comeau, Steeve; Connolly, Sean R; Cumming, Graeme S; Dalton, Steven J; Diaz-Pulido, Guillermo; Eakin, C Mark; Figueira, Will F; Gilmour, James P; Harrison, Hugo B; Heron, Scott F; Hoey, Andrew S; Hobbs, Jean-Paul A; Hoogenboom, Mia O; Kennedy, Emma V; Kuo, Chao-Yang; Lough, Janice M; Lowe, Ryan J; Liu, Gang; McCulloch, Malcolm T; Malcolm, Hamish A; McWilliam, Michael J; Pandolfi, John M; Pears, Rachel J; Pratchett, Morgan S; Schoepf, Verena; Simpson, Tristan; Skirving, William J; Sommer, Brigitte; Torda, Gergely; Wachenfeld, David R; Willis, Bette L; Wilson, Shaun K

    2017-03-15

    During 2015-2016, record temperatures triggered a pan-tropical episode of coral bleaching, the third global-scale event since mass bleaching was first documented in the 1980s. Here we examine how and why the severity of recurrent major bleaching events has varied at multiple scales, using aerial and underwater surveys of Australian reefs combined with satellite-derived sea surface temperatures. The distinctive geographic footprints of recurrent bleaching on the Great Barrier Reef in 1998, 2002 and 2016 were determined by the spatial pattern of sea temperatures in each year. Water quality and fishing pressure had minimal effect on the unprecedented bleaching in 2016, suggesting that local protection of reefs affords little or no resistance to extreme heat. Similarly, past exposure to bleaching in 1998 and 2002 did not lessen the severity of bleaching in 2016. Consequently, immediate global action to curb future warming is essential to secure a future for coral reefs.

  9. Fracture resistance and failure pattern of teeth submitted to internal bleaching with 37% carbamide peroxide, with application of different restorative procedures Resistência à fratura e padrão de falha de dentes submetidos ao clareamento interno com peróxido de carbamida a 37%, com aplicação de diferentes procedimentos restauradores

    Directory of Open Access Journals (Sweden)

    Gerson Bonfante

    2006-08-01

    Full Text Available OBJECTIVE: This study investigated the compressive fracture strength and failure pattern in premolars submitted to endodontic treatment and internal bleaching with 37% carbamide peroxide for 21 days, with application of different restorative procedures. MATERIAL AND METHODS: Six groups were employed (n = 10: 1 non-bleached teeth and pulp chamber sealed with IRM; 2 bleached teeth and pulp chamber sealed with IRM; 3 bleached teeth and pulp chamber filled with light cured composite resin; 4 bleached teeth, root canals prepared at 10mm, filling of the root canal and pulp chamber with IRM; 5 bleached teeth, root canals prepared at 10mm, luting of prefabricated metallic post with zinc phosphate and pulp chamber sealed with composite resin; 6 bleached teeth, root canals prepared at 10mm, luting of glass fiber post with resin cement and pulp chamber sealed with composite resin. After 24-hour storage in distilled water, the specimens were submitted to compressive fracture strength testing in a universal testing machine. RESULTS: The following values were found: Group 1 - 56.23kgf; Group 2 - 48.96kgf; Group 3 - 53.99kgf; Group 4 - 45.72kgf; Group 5 - 54.22kgf; Group 6 - 60.12kgf. The analysis of variance did not reveal statistically significant difference between groups (pOBJETIVO: O objetivo do estudo foi investigar a resistência à fratura sob compressão e padrão de falha de pré-molares tratados endodonticamente e clareados internamente por 21 dias com peróxido de carbamida a 37%, aplicando-se diferentes procedimentos restauradores. MATERIAL E MÉTODOS: O objetivo deste estudo foi investigar a resistência à fratura sob compressão e padrão de falha de pré-molares unirradiculares tratados endodonticamente e clareados internamente com peróxido de carbamida a 37%. Foram constituídos 6 grupos (n = 10: 1 dentes sem clareamento e câmara pulpar vedada com IRM; 2 dentes clareados e câmara pulpar vedada com IRM; 3 dentes clareados e câmara pulpar

  10. Kraft lignin chain extension chemistry via propargylation, oxidative coupling, and Claisen rearrangement.

    Science.gov (United States)

    Sen, Sanghamitra; Sadeghifar, Hasan; Argyropoulos, Dimitris S

    2013-10-14

    Despite its aromatic and polymeric nature, the heterogeneous, stochastic, and reactive characteristics of softwood kraft lignin seriously limit its potential for thermoplastic applications. Our continuing efforts toward creating thermoplastic lignin polymers are now focused at exploring propargylation derivatization chemistry and its potential as a versatile novel route for the eventual utilization of technical lignins with a significant amount of molecular control. To do this, we initially report the systematic propargylation of softwood kraft lignin. The synthesized derivatives were extensively characterized with thermal methods (DSC, TGA), (1)H, (13)C, and quantitative (31)P NMR and IR spectroscopies. Further on, we explore the versatile nature of the lignin pendant propargyl groups by demonstrating two distinct chain extension chemistries; the solution-based, copper-mediated, oxidative coupling and the thermally induced, solid-state, Claissen rearrangement polymerization chemistries. Overall, we show that it is possible to modulate the reactivity of softwood kraft lignin via a combination of methylation and chain extension providing a rational means for the creation of higher molecular weight polymers with the potential for thermoplastic materials and carbon fibers with the desired control of structure-property relations.

  11. Is Pulp Inflammation a Prerequisite for Pulp Healing and Regeneration?

    Directory of Open Access Journals (Sweden)

    Michel Goldberg

    2015-01-01

    Full Text Available The importance of inflammation has been underestimated in pulpal healing, and in the past, it has been considered only as an undesirable effect. Associated with moderate inflammation, necrosis includes pyroptosis, apoptosis, and nemosis. There are now evidences that inflammation is a prerequisite for pulp healing, with series of events ahead of regeneration. Immunocompetent cells are recruited in the apical part. They slide along the root and migrate toward the crown. Due to the high alkalinity of the capping agent, pulp cells display mild inflammation, proliferate, and increase in number and size and initiate mineralization. Pulp fibroblasts become odontoblast-like cells producing type I collagen, alkaline phosphatase, and SPARC/osteonectin. Molecules of the SIBLING family, matrix metalloproteinases, and vascular and nerve mediators are also implicated in the formation of a reparative dentinal bridge, osteo/orthodentin closing the pulp exposure. Beneath a calciotraumatic line, a thin layer identified as reactionary dentin underlines the periphery of the pulp chamber. Inflammatory and/or noninflammatory processes contribute to produce a reparative dentinal bridge closing the pulp exposure, with minute canaliculi and large tunnel defects. Depending on the form and severity of the inflammatory and noninflammatory processes, and according to the capping agent, pulp reactions are induced specifically.

  12. Vital Pulp Therapy—Current Progress of Dental Pulp Regeneration and Revascularization

    Directory of Open Access Journals (Sweden)

    Weibo Zhang

    2010-01-01

    Full Text Available Pulp vitality is extremely important for the tooth viability, since it provides nutrition and acts as biosensor to detect pathogenic stimuli. In the dental clinic, most dental pulp infections are irreversible due to its anatomical position and organization. It is difficult for the body to eliminate the infection, which subsequently persists and worsens. The widely used strategy currently in the clinic is to partly or fully remove the contaminated pulp tissue, and fill and seal the void space with synthetic material. Over time, the pulpless tooth, now lacking proper blood supply and nervous system, becomes more vulnerable to injury. Recently, potential for successful pulp regeneration and revascularization therapies is increasing due to accumulated knowledge of stem cells, especially dental pulp stem cells. This paper will review current progress and feasible strategies for dental pulp regeneration and revascularization.

  13. The potential for energy savings when reducing the water consumption in a kraft pulp mill

    Energy Technology Data Exchange (ETDEWEB)

    Wising, Ulrika; Berntsson, Thore [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Chemical Engineering and Environmental Science; Stuart, Paul [Ecole Polytechnique, Montreal (Canada). Dept. of Chemical Engineering

    2004-05-01

    In this paper an existing pulp and paper mill has been studied in a systematic way regarding the reduction of water consumption, and the resulting increased potential for energy integration. It has been found that when the mill's hot water consumption is decreased, the live steam demand for the mill also decreases. Also when decreasing the hot water consumption, the quantity and temperature of available excess heat increases. This excess heat can be used for evaporation, thereby reducing the live steam demand further by up to 1.5 GJ/t. A pinch analysis was performed at an existing mill and it was found that if pinch violations are removed, the hot water consumption is not an important factor any more. Removing all the pinch violations and using the remaining excess heat for evaporation yields a significantly larger energy savings for the mill (4.0 GJ/t). From an economic optimum perspective it is probably most profitable to do a combination of reducing water consumption, removing pinch violations, and use the remaining excess heat for evaporation.

  14. Structure-process-yield interrelations in nanocrystalline cellulose extraction

    Energy Technology Data Exchange (ETDEWEB)

    Hamad, W.Y.; Hu, T.Q. [FPInnovations, Vancouver, BC (Canada). Paprican Div.

    2010-06-15

    An understanding of the effect of hydrolysis conditions on yields of extracted water-insoluble cellulose materials is needed in order to understand the full potential of the extracted materials and the extent of their applications. This study provided a detailed analysis of the extraction of highly crystalline water-insoluble cellulose nanomaterials from commercial bleached kraft pulps using a sulfuric acid hydrolysis process. The process-yield-structure interrelations of the extracted materials were evaluated. The reproducibility of the hydrolysis process was evaluated, and methods of optimizing the yield of the extracted nanomaterials were explored. A Ruland-Rietveld analysis was used to resolve X-ray diffraction patterns and characterize crystallite size, crystalline and amorphous areas, and to determine the crystallinity of the extracted materials. The study showed that sulfation determines the yield of the materials and imparts the unique solid-state characteristics of the nanomaterials. The nanomaterials possessed iridescent patterns typical of chiral nematic materials. 27 refs., 3 tabs., 7 figs.

  15. Quantifying bleaching for zero-age fluvial sediment: A Bayesian approach

    International Nuclear Information System (INIS)

    Cunningham, Alastair C.; Evans, Mary; Knight, Jasper

    2015-01-01

    Luminescence dating of sediment requires the sand grains to have been exposed to sunlight prior to their most recent burial. Under fluvial transport, the amount of sunlight exposure may not always be sufficient to reset the luminescence signal, a phenomenon known as ‘partial bleaching'. The extent of bleaching is dependent on a combination of geomorphic, sedimentological and fluvial processes. If bleaching can be quantified, and the relationship with these processes understood, it could potentially be used as a new environmental proxy for changes in the dynamics of river systems. Here, we use a recently developed statistical model to evaluate the extent of bleaching, by inferring the proportion of well-bleached grains in the small-aliquot population. We sampled low-flow and flood deposits at a single site on the River Sabie, South Africa. We show that the low-flow sediment is almost perfectly bleached (>80% of grains well bleached), while sediment at flood elevations is partially bleached (20–70 % of grains well bleached). The degree of bleaching may show a relationship with flood magnitude as defined by elevation above normal river level, and we speculate on the causes of variability in bleaching between flood samples. - Highlights: • We sampled modern river sediment from low-flow and flood elevations. • The unbleached OSL dose was measured. • Bayesian methods can estimate the proportion of well-bleached grains. • Low-flow sediments are well bleached; flood deposits are poorly bleached.

  16. Component resolved bleaching study in natural calcium fluoride using CW-OSL, LM-OSL and residual TL glow curves after bleaching

    International Nuclear Information System (INIS)

    Angeli, Vasiliki; Polymeris, George S.; Sfampa, Ioanna K.; Tsirliganis, Nestor C.; Kitis, George

    2017-01-01

    Natural calcium fluoride has been commonly used as thermoluminescence (TL) dosimeter due to its high luminescence intensity. The aim of this work includes attempting a correlation between specific TL glow curves after bleaching and components of linearly modulated optically stimulated luminescence (LM-OSL) as well as continuous wave OSL (CW-OSL). A component resolved analysis was applied to both integrated intensity of the RTL glow curves and all OSL decay curves, by using a Computerized Glow-Curve De-convolution (CGCD) procedure. All CW-OSL and LM-OSL components are correlated to the decay components of the integrated RTL signal, apart from two RTL components which cannot be directly correlated with either LM-OSL or CW-OSL component. The unique, stringent criterion for this correlation deals with the value of the decay constant λ of each bleaching component. There is only one, unique bleaching component present in all three luminescence entities which were the subject of the present study, indicating that each TL trap yields at least three different bleaching components; different TL traps can indicate bleaching components with similar values. According to the data of the present work each RTL bleaching component receives electrons from at least two peaks. The results of the present study strongly suggest that the traps that contribute to TL and OSL are the same. - Highlights: • A component resolved bleaching study was attempted to CaF_2:N in terms of CW-OSL, LM-OSL and RTL. • Bleaching decay constants originating from different TL peaks yield overlapping values. • Three to five individual components were used in order to describe the bleaching behavior in all luminescence entities. • There is only one, unique bleaching component present in all three luminescence entities.

  17. Spectrophotometric and computerized evaluation of tooth bleaching employing 10 different home-bleaching procedures: In-vitro study

    Science.gov (United States)

    Peskersoy, Cem; Tetik, Ayhan; Ozturk, Veli Ozgen; Gokay, Necmi

    2014-01-01

    Objective: The aim of this in-vitro study was to evaluate the efficacy of bleaching products, determine the applicability and validation of the measurement methods. Materials and Methods: Freshly extracted 110 human incisor teeth were stained with whole blood and hemolysate solution prior to the application of 10 different home-bleaching products. Spectrophotometric measurements of the tooth shades were performed for each specimen before and after bleaching at the 1st, 3rd, 7th, and 14 days. Differences in lightness (Δl), chroma (Δc), hue (Δh) values and shade changes were measured to evaluate process. Computerized digital imaging analyses to determine the color changes were performed with Photoshop CS4 software (Adobe, San Jose, CA, USA). Statistical analyses were performed with analysis of variance, Scheffe and Tukey tests. Results: In all of the test groups regardless of the material used, a significant increase in lightness and hue, and decrease of chroma were observed, as compared to the control group. After recommended bleaching applications, Δl and Δh values respectively increased in group Zaris White and Brite (ZWB) and group Pola Night and Δc values showed significant decrease in groups ZWB and Rembrandt REM3 (P bleaching systems showed slower but almost permanent bleaching effect likewise office-based methods. Both software and spectrophotometric analyses have advantages such as evaluating the results objectively and numerically, also treatment outcomes could be preserved. PMID:25512738

  18. Incorporating adaptive responses into future projections of coral bleaching.

    Science.gov (United States)

    Logan, Cheryl A; Dunne, John P; Eakin, C Mark; Donner, Simon D

    2014-01-01

    Climate warming threatens to increase mass coral bleaching events, and several studies have projected the demise of tropical coral reefs this century. However, recent evidence indicates corals may be able to respond to thermal stress though adaptive processes (e.g., genetic adaptation, acclimatization, and symbiont shuffling). How these mechanisms might influence warming-induced bleaching remains largely unknown. This study compared how different adaptive processes could affect coral bleaching projections. We used the latest bias-corrected global sea surface temperature (SST) output from the NOAA/GFDL Earth System Model 2 (ESM2M) for the preindustrial period through 2100 to project coral bleaching trajectories. Initial results showed that, in the absence of adaptive processes, application of a preindustrial climatology to the NOAA Coral Reef Watch bleaching prediction method overpredicts the present-day bleaching frequency. This suggests that corals may have already responded adaptively to some warming over the industrial period. We then modified the prediction method so that the bleaching threshold either permanently increased in response to thermal history (e.g., simulating directional genetic selection) or temporarily increased for 2-10 years in response to a bleaching event (e.g., simulating symbiont shuffling). A bleaching threshold that changes relative to the preceding 60 years of thermal history reduced the frequency of mass bleaching events by 20-80% compared with the 'no adaptive response' prediction model by 2100, depending on the emissions scenario. When both types of adaptive responses were applied, up to 14% more reef cells avoided high-frequency bleaching by 2100. However, temporary increases in bleaching thresholds alone only delayed the occurrence of high-frequency bleaching by ca. 10 years in all but the lowest emissions scenario. Future research should test the rate and limit of different adaptive responses for coral species across latitudes and

  19. Effects of a Chitosan Coating Layer on the Surface Properties and Barrier Properties of Kraft Paper

    Directory of Open Access Journals (Sweden)

    Shanhui Wang

    2016-01-01

    Full Text Available Biodegradable chitosan can be applied as a coating on the surface of kraft paper in order to improve its barrier properties against water vapor and air. The food packaging industry can benefit from the addition of chitosan to its current packaging, and in turn reduce pollution from plastic packaging plants. This paper discusses the film formation of chitosan, the permeability of paper coated with a chitosan layer, and the influence on the paper’s surface and barrier properties under different process conditions. SEM (scanning electron microscope, AFM (atomic force microscope, ATR-FTIR (Fourier transmission infrared spectroscope with attenuated total reflection, and PDA (penetration dynamics analysis were used to analyze the properties of chitosan’s film formation and permeability. A controlled experiment showed that the chitosan layer was smoother than the surface of the uncoated kraft paper, had better film formation, and that there was no chitosan penetration through the kraft paper. The barrier properties against water vapor were strongest when there was a higher concentration of chitosan solution at the optimum pH, stirring speed, and those with a thicker coating on the kraft paper.

  20. Influência dos atributos do solo sobre a qualidade da madeira de Pinus taeda para produção de celulose Kraft Influence of soil attributes on quality of Pinus taeda wood for cellulose Kraft production

    Directory of Open Access Journals (Sweden)

    Patrícia Aparecida Rigatto

    2004-04-01

    characteristics, as well as their relation to cellulose production. Eight sites with twelve-year-old trees were selected based on soil type, soil texture and primary vegetation. The soil variables studied were bulk density, total porosity, macroporosity, water availability, fertility and grain size distribution. For tree selection, dendrometric measurements of 50 trees were taken per site, and 5 average size trees selected per site. Total and commercial height and DBH were measured and discs removed. Tree samples were analyzed for basic density, chemical composition, tracheid morphological characteristics, nutritional status and Kraft cellulose production. The soil chemical attributes exerted significant influence on wood quality, but the soil physical attributes showed greater influence on cellulose productivity. Sites with higher growth rate and those with clay texture showed lower values of basic density, higher content of extract and lignin, thus showing lower content of holocellulose and cellulose, shorter and wider tracheids with thinner walls and higher lumen diameters, and lower cellulose yield. Based on these results, it was concluded that cellulose pulp characteristics can be estimated by analyzing wood characteristics combined with the existing site edaphic conditions.

  1. Large-scale bleaching of corals on the Great Barrier Reef.

    Science.gov (United States)

    Hughes, T P; Kerry, J T; Simpson, T

    2018-02-01

    In 2015-2016, record temperatures triggered a pan-tropical episode of coral bleaching. In the southern hemisphere summer of March-April 2016, we used aerial surveys to measure the level of bleaching on 1,156 individual reefs throughout the 2,300 km length of the Great Barrier Reef, the world's largest coral reef system. The accuracy of the aerial scores was ground-truthed with detailed underwater surveys of bleaching at 260 sites (104 reefs), allowing us to compare aerial and underwater bleaching data with satellite-derived temperatures and with associated model predictions of bleaching. The severity of bleaching on individual reefs in 2016 was tightly correlated with the level of local heat exposure: the southernmost region of the Great Barrier Reef escaped with only minor bleaching because summer temperatures there were close to average. Gradients in nutrients and turbidity from inshore to offshore across the Great Barrier Reef had minimal effect on the severity of bleaching. Similarly, bleaching was equally severe on reefs that are open or closed to fishing, once the level of satellite-derived heat exposure was accounted for. The level of post-bleaching mortality, measured underwater after 7-8 months, was tightly correlated with the aerial scores measured at the peak of bleaching. Similarly, reefs with a high aerial bleaching score also experienced major shifts in species composition due to extensive mortality of heat-sensitive species. Reefs with low bleaching scores did not change in composition, and some showed minor increases in coral cover. Two earlier mass bleaching events occurred on the Great Barrier Reef in 1998 and 2002, that were less severe than 2016. In 2016, bleaching, compared to 42% in 2002 and 44% in 1998. Conversely, the proportion of reefs that were severely bleached (>60% of corals affected) was four times higher in 2016. The geographic footprint of each of the three events is distinctive, and matches satellite-derived sea surface

  2. Spatial consequences of bleaching adaptation in cat retinal ganglion cells.

    Science.gov (United States)

    Bonds, A B; Enroth-Cugell, C

    1981-01-01

    1. Experiments were conducted to study the effects of localized bleaching on the centre responses of rod-driven cat retinal ganglion cells. 2. Stimulation as far as 2 degrees from the bleaching site yielded responses which were reduced nearly as much as those generated at the bleaching site. Bleaching in the receptive field middle reduced responsiveness at a site 1 degrees peripheral more than bleaching at that peripheral site itself. 3. The effectiveness of a bleach in reducing centre responsiveness is related to the sensitivity of the region in which the bleach is applied. 4. Response reduction after a 0.2 degree bleach followed the same temporal pattern for concentric test spots of from 0.2 to 1.8 degrees in diameter, implying a substantially uniform spread of adaptation within these bounds. 5. A linear trade-off between fraction of rhodopsin and area bleached over a range of 8:1 yields the same pattern of response reduction, implying that the non-linear nature of bleaching adaptation is a property of the adaptation pool rather than independent photoreceptors. PMID:7320894

  3. BLEACHING IN VITAL TEETH: A LITERARY REVIEW

    Directory of Open Access Journals (Sweden)

    Felipe Fagundes Soares

    2007-12-01

    Full Text Available Tooth bleaching technique has presented a significant evolution, promoting higher satisfaction and comfort to the patients. Therefore, the aim of this study was to present the bleaching agents and the techniques, discussing advantages and disadvantages of each one, and the effect of these agents in the oral environment. The main agents used in the bleaching technique are the hydrogen peroxide and the carbamide peroxide, promoting the bleaching effect through oxidation of organic compounds. The application of these agents can be made at home or at a doctor office. During treatment, it may occur some adverse effects, such as tooth sensibility, increasing of dental porosity, and some interactions with the restorative material. However, these adverse effects can be eliminated or controlled when the treatment is executed under professional orientation. When the bleaching technique is well indicated and correctly conducted, it is associated with significantly positive results.

  4. Effect of light energy on peroxide tooth bleaching.

    Science.gov (United States)

    Luk, Karen; Tam, Laura; Hubert, Manfred

    2004-02-01

    Light-activated bleaching is a method of tooth whitening. The authors conducted a study to compare the whitening effects and tooth temperature changes induced by various combinations of peroxide bleaches and light sources. The authors randomly assigned 250 extracted human teeth halves into experimental groups (n = 10). A placebo gel (control), a 35 percent hydrogen peroxide or a 10 percent carbamide peroxide bleach was placed on the tooth surface and was irradiated with no light (control); a halogen curing light; an infrared, or IR, light; an argon laser; or a carbon dioxide, or CO2, laser. Color changes were evaluated immediately, one day and one week after treatment using a value-oriented shade guide and an electronic dental color analyzer. The outer enamel and inner dentin surface temperatures were monitored before and immediately after each 30-second application of light using a thermocouple thermometer. Color and temperature changes were significantly affected by an interaction of the bleach and light variables. The application of lights significantly improved the whitening efficacy of some bleach materials, but it caused significant temperature increases in the outer and inner tooth surfaces. The IR and CO2 laser lights caused the highest tooth temperature increases. Dentists performing an in-office bleaching technique with the use of an additional light source to accelerate tooth whitening should consider the specific bleaching agent being used, as well as the potential risks of heating teeth. A specific combination of bleach and light that demonstrates good color change and little temperature rise should be selected for in-office tooth bleaching.

  5. A novel paleo-bleaching proxy using boron isotopes and high-resolution laser ablation to reconstruct coral bleaching events

    OpenAIRE

    Dishon, G.; Fisch, J.; Horn, Ingo; Kaczmarek, Karina; Bijma, Jelle; Gruber, D.F.; Nir, O.; Popovich, Y.; Tchernov, D.

    2015-01-01

    Coral reefs occupy only ~ 0.1 percent of the ocean's habitat, but are the most biologically diverse marine ecosystem. In recent decades, coral reefs have experienced a significant global decline due to a variety of causes, one of the major causes being widespread coral bleaching events. During bleaching, the coral expels its symbiotic algae, thereby losing its main source of nutrition generally obtained through photosynthesis. While recent coral bleaching events have been ex...

  6. Effect of organosolv and soda pulping processes on the metals content of non-woody pulps.

    Science.gov (United States)

    González, M; Cantón, L; Rodríguez, A; Labidi, J

    2008-09-01

    In this work the effect of different pulping processes (ethyleneglycol, diethyleneglycol, ethanolamine and soda) of tow abounded raw materials (empty fruit bunches - EFB and rice straw) on the ash, silicates and metals (Fe, Zn, Cu, Pb, Mn, Ni and Cd) content of the obtained pulps have been studied. Results showed that pulps obtained by diethyleneglycol pulping process presented lower metals content (756 microg/g and 501 microg/g for EFB and rice straw pulp, respectively) than soda pulps (984 microg/g and 889 microg/g). Ethanolamine pulps presented values of holocellulose (74% and 77% for EFB and rice straw pulp, respectively), alpha-cellulose (74% and 69%), kappa number (18.7 and 18.5) and viscosity (612 and 90 6ml/g) similar to those of soda pulp, and lower lignin contents (11% and 12%).

  7. Bleaching of F-type centres in alkali halides

    International Nuclear Information System (INIS)

    Chandratillake, M.R.; Newton, G.W.A.; Robinson, V.J.

    1984-01-01

    Bleaching of the F band in KCl occurs on pulsing with 532 nm laser light. The bleaching is accompanied by the appearance of an absorption on the red side of the F band. Both bleaching and absorption are transient phenomena, and no permanent bleaching or absorption is observed. The same exponential lifetime of about 5μS was obtained for both bleaching and absorption, and all the features were found to be independent of both temperature (between 200 and 300 K) and the intensity of the analysing light. This eliminates the possibility of a trapped species, such as F - , being responsible. The phenomena are qualitatively different from the bleaching observed at low light intensity, where bleaching of the F band is accompanied by formation of F - , which is thermally stable below 250 K. The most likely explanation of the results is that the high concentration of conduction band electrons following the laser pulse allows formation of free or quasi-free electron pairs, e 2 - , which decay back into F centres on a time scale which is long compared with that for individual electrons. (author)

  8. Experimental Studies on the Hydrotreatment of Kraft Lignin to Aromatics and Alkylphenolics Using Economically Viable Fe-Based Catalysts

    NARCIS (Netherlands)

    Agarwal, Shilpa; Chowdari, Ramesh Kumar; Hita, Idoia; Heeres, Hero Jan

    Limonite, a low-cost iron ore, was investigated as a potential hydrotreatment catalyst for kraft lignin without the use of an external solvent (batch reactor, initial H-2 pressure of 100 bar, 4 h). The best results were obtained at 450 degrees C resulting in 34 wt % of liquefied kraft lignin (lignin

  9. Bleaching and diffusion dynamics in optofluidic dye lasers

    DEFF Research Database (Denmark)

    Gersborg-Hansen, Morten; Balslev, Søren; Mortensen, Asger

    2007-01-01

    The authors have investigated the bleaching dynamics that occur in optofluidic dye lasers where the liquid laser dye in a microfluidic channel is locally bleached due to optical pumping. They find that for microfluidic devices, the dye bleaching may be compensated through diffusion of dye molecules...

  10. Fractionation and characterization of saccharides and lignin components in wood prehydrolysis liquor from dissolving pulp production.

    Science.gov (United States)

    Wang, Zhaojiang; Wang, Xiaojun; Jiang, Jungang; Fu, Yingjuan; Qin, Menghua

    2015-08-01

    Saccharides and lignin components in prehydrolysis liquor (PHL) from kraft-based dissolving pulp production was characterized after being fractionated using membrane filtration. The results showed that the membrane filtration provided a method for organics fractionation with considerable recovery rate, but exhibited some disadvantages. Besides the limited ability in purifying oligosaccharides (OS) due to the overlaps of molecular weight distribution with lignin components, the membrane filtration could not improve the homogeneity of OS as indicated by the analysis of chemical compositions and the degree of polymerization (DP), which may be ascribed to the linear conformation of OS. The characterization of lignin components indicated a great potential for polymer industry because of the remarkable content of phenolic hydroxyl groups (PhOH), especially for low molecular weight (LMW) fraction. It was concluded the organics in PHL provided streams of value-added chemicals. However, the practical significance thereof can be realized and maximized only when they are successfully and completely fractionated. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Bleaching of the thermoluminescence of feldspars by sunlight

    International Nuclear Information System (INIS)

    Robertson, G.B.; Prescott, J.R.; Hutton, J.T.

    1991-01-01

    Feldspars are an important component of materials used for thermoluminescence (TL) and photoluminescence (PL) dating of sediments; and successful dating implies a knowledge of the degree of re-setting by exposure to sunlight of the stored luminescence energy. We have studied the bleaching by full sunlight of the TL of six alkali feldspars of representative composition and of one oligoclase. The high potassium and high sodium feldspars are the brightest, and are also the least easily bleached, whereas those of intermediate (K-Na) composition bleach quickly. On a time scale of upwards of 16 h, all samples would have bleached enough for them to be useful for TL dating. A search was made for individual glow curve peaks that bleach particularly quickly (and are thus similar to the well-known 325 o C peak used in the TL dating of quartz). In the samples studied, there was only one glow curve peak that was selectively susceptible to bleaching: the 280 o C peak in oligoclase. (author)

  12. Thermoluminescence emission spectra and optical bleaching of oligoclase

    International Nuclear Information System (INIS)

    Bos, A.J.J.; Piters, T.M.; Ypma, P.J.

    1994-01-01

    Thermoluminescence (TL) spectra of oligoclase samples have been recorded in the temperature range from 300 to 700 K and the wavelength range from 300 to 850 nm. Like other feldspars, oligoclase produces blue (peaking at 460 nm) and red (peaking at 765 nm) emission bands. The maximum of the red emission occurs 20 K lower than that of the blue band. Optical bleaching was performed at wavelengths varying from 360 to 800 nm. Bleaching of artificially irradiated oligoclase causes a decrease of the TL signal. The bleaching efficiency increases with decreasing wavelength. Bleaching does not only influence the height of the glow curve but also the shape. An interesting observation is that the ratio of the blue and red band intensities is not affected by a bleaching procedure. No evidence has been found that bleaching influences the shape of the emission spectra. The correlation between the blue and red bands is discussed. (Author)

  13. Evaluation of a value prior to pulping-thermomechanical pulp business concept. Part 2.

    Science.gov (United States)

    Ted Bilek; Carl Houtman; Peter Ince

    2011-01-01

    Value Prior to Pulping (VPP) is a novel biorefining concept for pulp mills that includes hydrolysis extraction of hemicellulose wood sugars and acetic acid from pulpwood prior to pulping. The concept involves conversion of wood sugars via fermentation to fuel ethanol or other chemicals and the use of remaining solid wood material in the pulping process. This paper...

  14. The effect of light-activation sources on tooth bleaching

    Science.gov (United States)

    Baroudi, Kusai; Hassan, Nadia Aly

    2014-01-01

    Vital bleaching is one of the most requested cosmetic dental procedures asked by patients who seek a more pleasing smile. This procedure consists of carbamide or hydrogen peroxide gel applications that can be applied in-office or by the patient (at-home/overnight bleaching system). Some in-office treatments utilise whitening light with the objective of speeding up the whitening process. The objective of this article is to review and summarise the current literature with regard to the effect of light-activation sources on in-office tooth bleaching. A literature search was conducted using Medline, accessed via the National Library of Medicine Pub Med from 2003 to 2013 searching for articles relating to effectiveness of light activation sources on in-office tooth bleaching. This study found conflicting evidence on whether light truly improve tooth whitening. Other factors such as, type of stain, initial tooth colour and subject age which can influence tooth bleaching outcome were discussed. Conclusions: The use of light activator sources with in-office bleaching treatment of vital teeth did not increase the efficacy of bleaching or accelerate the bleaching. PMID:25298598

  15. Effect of a New Bleaching Gel on Tooth Whitening.

    Science.gov (United States)

    Barry, T N; Bailey, C W; Ashcraft-Olmscheid, D; Vandewalle, K S

    The purpose of this study was to compare the whitening efficacy of a novel bleaching agent containing a unique tribarrel hydremide-peroxide gel (KöR) with a traditional bleaching system of hydrogen peroxide or carbamide peroxide (Opalescence). Bovine incisors were mounted into a custom resin, arch-shaped mounting device. Four groups of 10 teeth were created using mounting devices containing five teeth each. The in-office and home bleaching gels of KöR and Opalescence were applied to the teeth alone and in trays to simulate a combination of in-office and home bleaching or home bleaching only. Spectrophotometer readings of L* a* b* were performed at baseline, the end of active bleaching (immediate), and three and six months postbleaching. Immediately postbleaching, the use of Opalescence gel resulted in greater change in ΔE* and Δb* (less yellow) for combined and home bleaching techniques compared with KöR. After six months, Opalescence had significantly greater ΔE* and Δb* compared with KöR for home bleaching only. There was no significant difference in ΔL* between Opalescence and KöR at any time period with either technique.

  16. In vitro colorimetric evaluation of the efficacy of home bleaching and over-the-counter bleaching products.

    Science.gov (United States)

    Dietschi, Didier; Benbachir, Nacer; Krejci, Ivo

    2010-06-01

    Various bleaching modalities are now offered to patients, either monitored by the dental office or self-directed, for which relative efficiency is unknown. The aim of this in vitro study was to evaluate the ability of bleaching products and protocols to lighten enamel and dentin. Bovine tooth specimens of standardized thickness (2.5 +/- 0.025 mm with similar dentin and enamel thickness) were prepared and stained with whole blood and hemolysate before being submitted to seven supervised or self-directed bleaching regimens: tray-based bleaching using 10% (Opalescence, Ultradent; Nite White, Discus Dental) or light-activated 30% (Metatray, Metatray) carbamide peroxide (CP); 6% (Zoom, Discus Dental) or 9% (TresWhite, Ultradent) hydrogen peroxide (HP); strips (Whitening Strips, Oral B-Rembrandt); and paint-on gel (Paint on Plus, Ivoclar Vivadent) containing 8.1% and 6% HP, respectively. Colorimetric measurements were performed on each specimen side, according to the CIE L*a*b* system, before and after staining, as well as after 5, 10, and the recommended number of bleaching applications. Color change after recommended number of applications (DEr) varied from 15.72 (Metatray) to 29.67 (Nite White) at enamel and 14.91 (Paint on Plus) to 41.43 (Nite White) at dentin side; Nite White (10% CP) and TresWhite (9% HP) were more effective than Metatray (30% CP) and Paint on Plus (6% HP) after 5 or the recommended number of applications. In this in vitro study based on bovine teeth, tray-based systems produced the faster and better bleaching effect, regardless of the product and concentration used, at both enamel and dentin sides.

  17. A new, high-resolution global mass coral bleaching database.

    Directory of Open Access Journals (Sweden)

    Simon D Donner

    Full Text Available Episodes of mass coral bleaching have been reported in recent decades and have raised concerns about the future of coral reefs on a warming planet. Despite the efforts to enhance and coordinate coral reef monitoring within and across countries, our knowledge of the geographic extent of mass coral bleaching over the past few decades is incomplete. Existing databases, like ReefBase, are limited by the voluntary nature of contributions, geographical biases in data collection, and the variations in the spatial scale of bleaching reports. In this study, we have developed the first-ever gridded, global-scale historical coral bleaching database. First, we conducted a targeted search for bleaching reports not included in ReefBase by personally contacting scientists and divers conducting monitoring in under-reported locations and by extracting data from the literature. This search increased the number of observed bleaching reports by 79%, from 4146 to 7429. Second, we employed spatial interpolation techniques to develop annual 0.04° × 0.04° latitude-longitude global maps of the probability that bleaching occurred for 1985 through 2010. Initial results indicate that the area of coral reefs with a more likely than not (>50% or likely (>66% probability of bleaching was eight times higher in the second half of the assessed time period, after the 1997/1998 El Niño. The results also indicate that annual maximum Degree Heating Weeks, a measure of thermal stress, for coral reefs with a high probability of bleaching increased over time. The database will help the scientific community more accurately assess the change in the frequency of mass coral bleaching events, validate methods of predicting mass coral bleaching, and test whether coral reefs are adjusting to rising ocean temperatures.

  18. A new, high-resolution global mass coral bleaching database.

    Science.gov (United States)

    Donner, Simon D; Rickbeil, Gregory J M; Heron, Scott F

    2017-01-01

    Episodes of mass coral bleaching have been reported in recent decades and have raised concerns about the future of coral reefs on a warming planet. Despite the efforts to enhance and coordinate coral reef monitoring within and across countries, our knowledge of the geographic extent of mass coral bleaching over the past few decades is incomplete. Existing databases, like ReefBase, are limited by the voluntary nature of contributions, geographical biases in data collection, and the variations in the spatial scale of bleaching reports. In this study, we have developed the first-ever gridded, global-scale historical coral bleaching database. First, we conducted a targeted search for bleaching reports not included in ReefBase by personally contacting scientists and divers conducting monitoring in under-reported locations and by extracting data from the literature. This search increased the number of observed bleaching reports by 79%, from 4146 to 7429. Second, we employed spatial interpolation techniques to develop annual 0.04° × 0.04° latitude-longitude global maps of the probability that bleaching occurred for 1985 through 2010. Initial results indicate that the area of coral reefs with a more likely than not (>50%) or likely (>66%) probability of bleaching was eight times higher in the second half of the assessed time period, after the 1997/1998 El Niño. The results also indicate that annual maximum Degree Heating Weeks, a measure of thermal stress, for coral reefs with a high probability of bleaching increased over time. The database will help the scientific community more accurately assess the change in the frequency of mass coral bleaching events, validate methods of predicting mass coral bleaching, and test whether coral reefs are adjusting to rising ocean temperatures.

  19. Coral bleaching--capacity for acclimatization and adaptation.

    Science.gov (United States)

    Coles, S L; Brown, Barbara E

    2003-01-01

    Coral bleaching, i.e., loss of most of the symbiotic zooxanthellae normally found within coral tissue, has occurred with increasing frequency on coral reefs throughout the world in the last 20 years, mostly during periods of El Nino Southern Oscillation (ENSO). Experiments and observations indicate that coral bleaching results primarily from elevated seawater temperatures under high light conditions, which increases rates of biochemical reactions associated with zooxanthellar photosynthesis, producing toxic forms of oxygen that interfere with cellular processes. Published projections of a baseline of increasing ocean temperature resulting from global warming have suggested that annual temperature maxima within 30 years may be at levels that will cause frequent coral bleaching and widespread mortality leading to decline of corals as dominant organisms on reefs. However, these projections have not considered the high variability in bleaching response that occurs among corals both within and among species. There is information that corals and their symbionts may be capable of acclimatization and selective adaptation to elevated temperatures that have already resulted in bleaching resistant coral populations, both locally and regionally, in various areas of the world. There are possible mechanisms that might provide resistance and protection to increased temperature and light. These include inducible heat shock proteins that act in refolding denatured cellular and structural proteins, production of oxidative enzymes that inactivate harmful oxygen radicals, fluorescent coral pigments that both reflect and dissipate light energy, and phenotypic adaptations of zooxanthellae and adaptive shifts in their populations at higher temperatures. Such mechanisms, when considered in conjunction with experimental and observational evidence for coral recovery in areas that have undergone coral bleaching, suggest an as yet undefined capacity in corals and zooxanthellae to adapt to

  20. Recruitment of dental pulp cells by dentine and pulp extracellular matrix components.

    Science.gov (United States)

    Smith, J G; Smith, A J; Shelton, R M; Cooper, P R

    2012-11-01

    The present study aimed to determine whether dentine tissue and preparations of extracellular matrix (ECM) from pulp (pECM) and dentine (dECM), and breakdown products, influenced pulp cell migration. Chemotaxis transwell and agarose spot assays demonstrated that both dentine and pulp ECM molecules acted as chemoattractants for primary pulp cells. Chemoattractant activities of dECM and pECM were enhanced when subjected to acid and enzymatic breakdown, respectively. This enhanced activity following physiologically relevant breakdown may be pertinent to the disease environment. Pulp cell migration in response to dental ECMs was dependent on an active rho pathway. Recruited cells exhibited increased stem cell marker expression indicating that dental ECMs and their breakdown products selectively attract progenitor cells that contribute to repair processes. In conclusion, combined these results indicate that ECM molecules contribute to cell recruitment necessary for regeneration of the dentine-pulp complex after injury. Copyright © 2012 Elsevier Inc. All rights reserved.

  1. Radiation -adsorption treatment of pesticides by using wood pulp and bagasse pulp

    International Nuclear Information System (INIS)

    Abd El-Aal, S.E.; Sokker, S.S.; Dessooki, A.M.

    2005-01-01

    Alkaline pulping of pulp wood and bagasse using sodium hydroxide resulted in the reduction of lignin from the wood and bagasse fibers and consequently increase adsorption of the pesticide pollutants to these fibers. Three different types of pesticides were used in this study namely, metalaxyl, dicloran and arelon. which were irradiated at a dose of 4 kGy before adsorption treatment.The results show that moderate adsorption was observed for all pesticides when adsorption was carried out without alkaline pulping and irradiation. This is due to the presence of lignin which retard the adsorption process. Batch sorption experiments at different pH values (3, 7, 9) for the retention of these pesticides by pulp wood and pulp bagasse fibers indicated that sorption is governed by the interaction of the ionized form of these compounds with the polyhydroxyl structure of cellulose. The study shows that alkaline pulping of pulpwood and bagasse improves its ability towards adsorption of the radiation degraded pesticide molecules

  2. Spectrophotometric assessment of tooth bleaching under orthodontic braquets bonded with different materials

    Directory of Open Access Journals (Sweden)

    Camila Maria Lima de CASTRO

    2017-10-01

    Full Text Available Abstract Introduction patients have been submitted to tooth bleaching during orthodontic treatment for aesthetic purposes or to anticipate the replacement of restorations after completion of the treatment. Objective to evaluate the effectiveness of tooth bleaching under orthodontic brackets bonded with different materials. Material and method a hundred bovine enamel blocks were divided into two groups, at-home and in-office tooth bleaching. In-office bleaching was subdivided into five groups (n = 10: HP (control - without brackets; SA(t - brackets bonded with Transbond XT, without bleaching; SA(fm - brackets bonded with Orthodontic Fill Magic, without bleaching; HP(t - brackets bonded with Transbond XT subjected to bleaching; and HP(fm - brackets bonded with Orthodontic Fill Magic subjected to bleaching. At-home bleaching followed the same treatments, only replacing the bleaching agent. Spectrophotometric assessment was used for tooth color determination at three moments: 1 before staining (baseline; 2 after staining; 3 after bonding the brackets and bleaching procedures. Data were submitted to ANOVA and analyzed by Tukey's test (p < 0.05. Result For both types of bleaching, the control group had an effective bleaching action. Groups using Transbond XT presented greater bleaching potential among the groups with orthodontic accessory, but the bleaching action differed from the positive control. Groups using Orthodontic Fill Magic presented no bleaching action, resembling the negative control groups (artificial saliva. Conclusion the orthodontic bracket impaired the effectiveness of the at-home and in-office bleaching treatment, regardless of the resin used for bonding.

  3. Celulose monossulfito a partir de Bambusa vulgaris schrad Alkaline monosulphite pulping of Bambusa vulgaris schrad

    Directory of Open Access Journals (Sweden)

    Anísio Azzini

    1979-01-01

    Full Text Available Em condições de laboratório foram produzidas pastas celulósicas pelo processo alcalino monossulfito, com várias concentrações dos reagentes químicos, sulfito de sódio e licor-verde sulfato. As propriedades dessas celuloses foram comparadas com aquelas da celulose obtida pelo processo sulfato (kraft de uso generalizado pela indústria de celulose e papel. As características físico-mecânicas e ópticas das celuloses monossulfito e sulfato foram satisfatórias e semelhantes, com exceção da resistência ao rasgo, que na celulose sulfato foi maior. Os cavacos utilizados, nas dimensões de 5,5 x 0,8 x 0,5cm, respectivamente para comprimento, largura e espessura, foram adequados ao processo sulfato e inadequados às condições do processo monossulfito, que produziu celulose com menor rendimento depurado, maior porcentagem de rejeitos e maior teor de lignina residual nas fibras, determinado pelo número kappa. A densidade básica e as dimensões das fibras variaram no sentido radial do colmo, principalmente a densidade básica, cujos valores decresceram acentuadamente da camada externa para a interna.Pulps in laboratory conditions were obtained from Bambusa vulgaris Schrad by the alkaline monosulphite process, with various concentrations of the cooking chemicals. The strength properties of these pulps were compared to those obtained by the sulphate process. The results showed that both pulps were similar, excepting the tear resistance that was higher in the sulphate one. It was observed that chips with 5.5 x 0.8 x 0.5cm, respectively to the length, width and thickness were appropriated to the sulphate process but not to the conditions of the alkaline monosulphate process, which produced pulps with low values in terms of screening yield, percentage of screenings and kappa number. The variability of bamboo culm in the radial direction was also determined regarding basic density and fiber dimensions. The results showed variations in those

  4. Changes in coral-associated microbial communities during a bleaching event.

    Science.gov (United States)

    Bourne, David; Iida, Yuki; Uthicke, Sven; Smith-Keune, Carolyn

    2008-04-01

    Environmental stressors such as increased sea surface temperatures are well-known for contributing to coral bleaching; however, the effect of increased temperatures and subsequent bleaching on coral-associated microbial communities is poorly understood. Colonies of the hard coral Acropora millepora were tagged on a reef flat off Magnetic Island (Great Barrier Reef) and surveyed over 2.5 years, which included a severe bleaching event in January/February 2002. Daily average water temperatures exceeded the previous 10-year average by more than 1 degrees C for extended periods with field-based visual surveys recording all tagged colonies displaying signs of bleaching. During the bleaching period, direct counts of coral zooxanthellae densities decreased by approximately 64%, before recovery to pre-bleaching levels after the thermal stress event. A subset of three tagged coral colonies were sampled through the bleaching event and changes in the microbial community elucidated. Denaturing gradient gel electrophoresis (DGGE) analysis demonstrated conserved bacterial banding profiles between the three coral colonies, confirming previous studies highlighting specific microbial associations. As coral colonies bleached, the microbial community shifted and redundancy analysis (RDA) of DGGE banding patterns revealed a correlation of increasing temperature with the appearance of Vibrio-affiliated sequences. Interestingly, this shift to a Vibrio-dominated community commenced prior to visual signs of bleaching. Clone libraries hybridized with Vibrio-specific oligonucleotide probes confirmed an increase in the fraction of Vibrio-affiliated clones during the bleaching period. Post bleaching, the coral microbial associations again shifted, returning to a profile similar to the fingerprints prior to bleaching. This provided further evidence for corals selecting and shaping their microbial partners. For non-bleached samples, a close association with Spongiobacter-related sequences were

  5. Coral mass bleaching and reef temperatures at Navassa Island, 2006

    Science.gov (United States)

    Miller, M. W.; Piniak, G. A.; Williams, D. E.

    2011-01-01

    Bleaching and associated mortality is an extreme threat to the persistence of coral populations in the projected warming regime of the next few decades. Recent evidence indicates that thermal bleaching thresholds may be affected by water quality gradients. The unexpected encounter of a coral mass bleaching event at a remote, uninhabited Caribbean island (Navassa) during a routine reef assessment cruise in November 2006 provided the opportunity to characterize bleaching responses and thermal exposure in an oceanic area with negligible continental influence or human impact on water quality. The coral taxa most susceptible to bleaching were Agaricia spp. and Montastraea faveolata. Siderastraea siderea, Diploria spp. and Porites porites were intermediately affected, while Porites astreoides and Montastraea cavernosa were minimally affected and negligible bleaching was observed in Acropora palmata. Bleaching prevalence (colonies > 4 cm diameter) ranged from 0.16 to 0.63 among sites. Deeper sites (between 18 and 37 m) had significantly higher prevalence of bleaching than shallow sites (<10 m). This general pattern of more bleaching in deeper sites also occurred within species. Though exposure to high-temperature stress was not greater at deeper sites, water motion, which may bolster bleaching resistance, was likely less. In situ loggers indicated temperatures over 30 °C initiated at shallow sites in mid-August, at deeper sites in early September, and were persistent at all sites until mid-October. Long term (1983-2007) climatologies constructed from AVHRR SSTs suggest that the mass bleaching event observed at Navassa in 2006 corresponded with greater intensity and duration of warm temperature anomalies than occurred in 2005, for which no in situ observations (bleaching nor temperature) are available.

  6. Coral community response to bleaching on a highly disturbed reef.

    Science.gov (United States)

    Guest, J R; Low, J; Tun, K; Wilson, B; Ng, C; Raingeard, D; Ulstrup, K E; Tanzil, J T I; Todd, P A; Toh, T C; McDougald, D; Chou, L M; Steinberg, P D

    2016-02-15

    While many studies of coral bleaching report on broad, regional scale responses, fewer examine variation in susceptibility among coral taxa and changes in community structure, before, during and after bleaching on individual reefs. Here we report in detail on the response to bleaching by a coral community on a highly disturbed reef site south of mainland Singapore before, during and after a major thermal anomaly in 2010. To estimate the capacity for resistance to thermal stress, we report on: a) overall bleaching severity during and after the event, b) differences in bleaching susceptibility among taxa during the event, and c) changes in coral community structure one year before and after bleaching. Approximately two thirds of colonies bleached, however, post-bleaching recovery was quite rapid and, importantly, coral taxa that are usually highly susceptible were relatively unaffected. Although total coral cover declined, there was no significant change in coral taxonomic community structure before and after bleaching. Several factors may have contributed to the overall high resistance of corals at this site including Symbiodinium affiliation, turbidity and heterotrophy. Our results suggest that, despite experiencing chronic anthropogenic disturbances, turbid shallow reef communities may be remarkably resilient to acute thermal stress.

  7. Therapeutic effectiveness of a new enzymatic bleaching dentifrice.

    Science.gov (United States)

    Forner, Leopaldo; Amengual, José; Liena, Carmen; Riutord, Pere

    2012-01-01

    Research into bleaching focuses on new products in order to minimize undesirable effects. This study evaluated the bleaching effectiveness of a new enzymatic-activated dentifrice. A total of 20 volunteers were bleached with a dentifrice containing 5% lactoperoxidase and 3% carbamide peroxide applied three times a day for two minutes over 21 days. Color was recorded before and after the treatment using a spectrophotometer. CIELAB differences were calculated before and after treatment using the paired t test (P whitening teeth. Enzymatic dental bleaching is able to increase the efficiency of low concentration peroxides, reducing the potential risk of peroxides on oral tissues.

  8. Effect of coffe and a cola-based soft drink on the color stability of bleached bovine incisors considering the time elapsed after bleaching

    Directory of Open Access Journals (Sweden)

    Rodrigo PIROLO

    2014-12-01

    Full Text Available There is no consensus about the waiting time necessary for the patient to start consuming beverages containing colorants again after bleaching. Objective: To evaluate the influence of beverages with coloring agents on bleached bovine incisors considering the time elapsed after bleaching. Materials and methods: Sixty bovine incisors were bleached with 35% hydrogen peroxide for in-office use (Whiteness HP Max and divided into 10 groups. The color was evaluated with a spectrophotometer (Spectro Shade MICRO before and after bleaching, employing the CIE-Lab system. After bleaching, the teeth were exposed for 5 min to coffee or cola-based soft drink (CBSD at different periods after bleaching: 10 min, 1 h, 24 h, 48 h, and 72 h. Color (∆E and lightness (∆L variations were obtained from the CIE-Lab coordinates. Data were subjected to two-way ANOVA and Tukey HSD tests (p<0.05. Results: Significant differences were observed between groups for both the ∆L and ∆E values (p<0.001. All specimens presented a decrease in brightness (negative ∆L. The highest ∆E values were observed for teeth stained with a CBSD at 10 min and 1 h (4.12 and 4.16, respectively. Teeth pigmented with coffee presented ∆E values below 3.3 units for all evaluation times. Conclusion: The exposure to coffee after bleaching causes less color changes than the exposure to a CBSD regardless of the time after bleaching.

  9. Effects of Alkali Treatment and Polyisocyanate Crosslinking on the Mechanical Properties of Kraft Fiber-Reinforced Unsaturated Polyester Composites

    Directory of Open Access Journals (Sweden)

    Zhenhua Gao

    2014-08-01

    Full Text Available The effects of alkali treatment and polyisocyanate crosslinking on the mechanical properties of kraft fiber-reinforced UPE composites were investigated by means of tensile evaluation, SEM analysis, and XRD analysis. The results indicated that the alkali treatment decreased the tensile strength of the prepared composite before aging from 121 MPa to 97 MPa due to the decreased degree of crystallinity of the alkali-treated kraft fiber. Polyisocyanate crosslinking could apparently improve the mechanical properties and stability in terms of a 43% increase of non-aged tensile strength and 52% increase of hydrothermal-aged tensile strength compared with the controlled composite without crosslinking modification, which was attributable to the formation of strong chemical bonding between the interfaces of kraft fiber and polyester.

  10. In situ observations of coral bleaching in the central Saudi Arabian Red Sea during the 2015/2016 global coral bleaching event.

    Science.gov (United States)

    Monroe, Alison A; Ziegler, Maren; Roik, Anna; Röthig, Till; Hardenstine, Royale S; Emms, Madeleine A; Jensen, Thor; Voolstra, Christian R; Berumen, Michael L

    2018-01-01

    Coral bleaching continues to be one of the most devastating and immediate impacts of climate change on coral reef ecosystems worldwide. In 2015, a major bleaching event was declared as the "3rd global coral bleaching event" by the United States National Oceanic and Atmospheric Administration, impacting a large number of reefs in every major ocean. The Red Sea was no exception, and we present herein in situ observations of the status of coral reefs in the central Saudi Arabian Red Sea from September 2015, following extended periods of high temperatures reaching upwards of 32.5°C in our study area. We examined eleven reefs using line-intercept transects at three different depths, including all reefs that were surveyed during a previous bleaching event in 2010. Bleaching was most prevalent on inshore reefs (55.6% ± 14.6% of live coral cover exhibited bleaching) and on shallower transects (41% ± 10.2% of live corals surveyed at 5m depth) within reefs. Similar taxonomic groups (e.g., Agariciidae) were affected in 2015 and in 2010. Most interestingly, Acropora and Porites had similar bleaching rates (~30% each) and similar relative coral cover (~7% each) across all reefs in 2015. Coral genera with the highest levels of bleaching (>60%) were also among the rarest (coral cover) in 2015. While this bodes well for the relative retention of coral cover, it may ultimately lead to decreased species richness, often considered an important component of a healthy coral reef. The resultant long-term changes in these coral reef communities remain to be seen.

  11. Temperament and perception of tooth bleaching results

    Directory of Open Access Journals (Sweden)

    Katarzyna Mehr

    2016-09-01

    Full Text Available Background . The neurophysiological process of perceiving the results of tooth bleaching requires the correct interaction between the central nervous system and the organs of sight. Exaggerated beliefs concerning defective facial features may enhance inner attitudes about one’s own color of dentition, as well as a feeling of dissatisfaction with the degree of leaching. Objectives. The study aimed to assess the degree of the patient satisfaction with the results of tooth bleaching in relation to their temperament. Material and methods. There were 68 generally healthy volunteers, aged 28–38 years, with external discolorations of the teeth. They had never undergone dental bleaching and their frontal teeth did not have any fillings. After clinical evaluation and the completion of formalities, the patients were asked to fill in Strelau’s temperament questionnaire. Questionnaires and visual status were assessed three times by three doctors: before bleaching, and then 24 hours and two weeks after the home-bleaching operation, which was done with the use of Opalescence (Ultradent in uniform sequence. Results . There were practically no adverse side results, except a periodic dentin hypersensitivity that occurred periodically in 44 patients. The results of the visual assessment performed by the physicians did not differ. The questionnaire data showed that women were more critical of the results in relation to the expectations. Among elancholics, full satisfaction was declared by 41%, whereas among sanguine people, full satisfaction was obtained by 85%. Satisfaction with the aesthetic results was associated with bleaching by at least 4 degrees. Conclusions . Patients’ temperament affects their subjective evaluation of the effectiveness of tooth bleaching, which should be taken into consideration in the patient’s individual dental treatment plan.

  12. The effects of habitat on coral bleaching responses in Kenya.

    Science.gov (United States)

    Grimsditch, Gabriel; Mwaura, Jelvas M; Kilonzo, Joseph; Amiyo, Nassir

    2010-06-01

    This study examines the bleaching responses of scleractinian corals at four sites in Kenya (Kanamai, Vipingo, Mombasa and Nyali) representing two distinct lagoon habitats (relatively shallow and relatively deep). Bleaching incidence was monitored for the whole coral community, while zooxanthellae densities and chlorophyll levels were monitored for target species (Pocillopora damicornis, Porites lutea, and Porites cylindrica) during a non-bleaching year (2006) and a year of mild-bleaching (2007). Differences in bleaching responses between habitats were observed, with shallower sites Kanamai and Vipingo exhibiting lower bleaching incidence than deeper sites Nyali and Mombasa. These shallower lagoons display more fluctuating thermal and light environments than the deeper sites, suggesting that corals in the shallower lagoons have acclimatized and/or adapted to the fluctuating environmental conditions they endure on a daily basis and have become more resistant to bleaching stress. In deeper sites that did exhibit higher bleaching (Mombasa and Nyali), it was found that coral recovery occurred more quickly in the protected area than in the non-protected area.

  13. Clinical Evaluation of Genotoxicity of In-office Bleaching.

    Science.gov (United States)

    Rezende, M; De Geus, J L; Loguercio, A D; Reis, A; Kossatz, D

    The aim of this study was to evaluate the genotoxicity of in-office bleaching with 35% hydrogen peroxide in epithelial cells from the gingival and lip tissues. Thirty volunteers with central incisors shade A1 or darker were selected for this study. The gingival tissue of the teeth to be bleached was isolated with a light-polymerized resin dam, and the 35% hydrogen peroxide gel was administered during three 15-minute applications over the course of the 45-minute application period. Two bleaching sessions with a one-week interval in between were performed. Exfoliated oral mucosa gingival epithelial cells and upper lip lining were collected at baseline and one month after the in-office dental bleaching. The scraped cells were placed on clean glass slides and smears were prepared. After staining with Giemsa solution, two blinded examiners performed cell and micronuclei counts under a 100× optical microscope. Tooth sensitivity was evaluated using the Visual Analogue Scale (VAS). Shade evaluation was recorded before and one month after the bleaching treatment with the value-oriented shade guide Vita Bleachedguide 3D-MASTER and the spectrophotometer Vita Easyshade. Data from the shade guide units and the micronuclei (MN) frequency were subjected to a Mann-Whitney test (α=0.05). The overall difference between before and one month after the bleaching treatment (ΔE and ΔSGU), absolute risk, and intensity of tooth sensitivity (TS) were calculated, as was the 95% confidence interval (CI). The frequency of MN was not increased after bleaching with 35% hydrogen peroxide in both study groups (p>0.05). The absolute risk of TS of the participants was 93% (95% CI, 79%-98%), with a mean VAS intensity of 5.7 ± 2.9 (95% CI, 4.6-6.8). Meaningful whitening was observed after bleaching. The change in shade guide units in the Bleachedguide 3D-MASTER was 2.3 ± 1.4. In terms of ΔE, the change in color was 7.7 ± 3.5. The in-office bleaching did not induce DNA damage to the gingival

  14. In vitro Assessment of Influence of Various Bleaching Protocols on the Strength of Ceramic Orthodontic Brackets bonded to Bleached Tooth Surface: A Comparative Study.

    Science.gov (United States)

    Iska, Divya; Devanna, Raghu; Singh, Madhvi; Chitumalla, Rajkiran; Balasubramanian, Sai C Bala; Goutam, Manish

    2017-12-01

    Esthetics is one of the common issues because of which patients consult dental orthodontic treatment. Two ways of tooth bleaching are available these days, which includes in-office bleach and home bleach. Various bleaching protocols are available these days for treating the tooth surfaces. Hence, we planned the present study for investigating the impact of various intracoronal bleaching protocols on shear bond strength of ceramic brackets bonded to tooth surface after bleaching. The present study included assessment of 100 extracted maxillary central incisors with the integrated buccal surface. A resin block was made and individual teeth were embedded in each block. Root canal therapy procedure was performed in all the teeth, after which 2 mm short of tooth apex up to the level of cementoenamel junction, removal of the root canal filling was done. All the samples were broadly divided into four study groups with 25 samples in each group. Bleaching procedure was carried in all the samples intracoronally followed by testing of shear bond strength using universal force testing machine. Following the modified adhesive remnant index (AI), assessment of remaining adhesive on the brackets was done. All the results were compiled and analyzed by Statistical Package for the Social Sciences (SPSS) software version 17.0. In the control group, mean shear bond strength was found to be 17.9 MPa. While comparing the carbamide peroxide (CP) group with sodium perborate study group, we observed a statistically significant difference. Nonsignificant results were obtained while comparing the shear bond strength in between sodium perborate group and hydrogen peroxide (HP) group. Intracoronal bleaching does affect the shear bond strength of ceramic brackets. Sodium perborate bleaching influences shear bond strength more strongly than other bleaching agents such as CP and HP. In patients undergoing orthodontic treatment, HP is a preferred agent where bleaching has to be followed by

  15. Effects of Soda-Anthraquinone Pulping Variables on the Durian Rind Pulp and Paper Characteristics: A Preliminary Test

    Science.gov (United States)

    Rizal Masrol, Shaiful; Irwan Ibrahim, Mohd Halim; Adnan, Sharmiza; Rahmad Talib, Mohd; Sian, Lau Lee

    2017-08-01

    Good combination of pulping variables is required to obtain the quality pulp and paper characteristics. Thus, in this preliminary work, naturally dried durian rind were pulped under Soda-Anthraquinone (Soda-AQ) pulping process with 18% to 22% alkali charge, 0% to 0.1% Anthraquinone (AQ) charge, 90 minutes to 150 minutes of cooking time and 150°C to 170°C to investigate the effect of pulping variables on the characteristics of the pulp and paper. Pulping condition with 0% of AQ charge was also conducted for comparison. Results indicated that the best screen yield percentage, reject yield percentage, freeness, drainage time, tear index, number of folds and optical properties were shown by the pulp produced with combination of the highest active alkali (22%), AQ charge (0.1%), cooking time (150 minutes) and cooking temperature (170°C) except apparent density, tensile index and burst index. This preliminary result shows that the optimum quality of durian rind pulp as a potential papermaking raw material pulp could be produced by selecting the good combination of pulping variables which influences the pulp and paper characteristics.

  16. Reuse of discarded deactivated bleaching earth in the bleaching of oils

    Directory of Open Access Journals (Sweden)

    Girgis, Adel Y.

    2005-03-01

    Full Text Available Discarded bleaching earth was used after its reactivation for the bleaching of sunflower, soybean and corn oils. The efficiency of reactivated bleaching earth was compared to the efficiency of virgin activated bleaching earth. Acid reactivated earth (pH 2.5-3 had a slightly higher content in silicone than virgin activated or neutralized reactivated earths. The best results in the color of sunflower and corn oils were obtained when neutralized earth (pH 6–7 was used at 1 and 2 % levels. Acid reactivated earth used at 2 % achieved a higher reduction in soybean oil color than virgin earth (pH 3 at the same dosage. Both reactivated earths reduced peroxide value, iron, conjugated dienes and soap, while they increased acidity and conjugated trienes. Furthermore, these reactivated earths determined higher decrements in the oil induction period than virgin earth. Reactivated earth could be used for 5 cycles for the bleaching of soybean or corn oils and for more than 6 cycles for sunflower oil.Tierra decolorante desechada, fue empleada, tras su reactivación para decolorar aceites de girasol, soja y maíz. La eficiencia de la tierra decolorante reactivada fue comparada con la de la virgen activada. La tierra reactivada ácida (pH 2,5–3 tuvo ligeramente mayor contenido en silicona que la tierra virgen o la reactivada neutra. Los mejores resultados en el color de los aceites de girasol y maíz fueron obtenidos cuando se emplearon niveles del 1 y 2 % de tierra reactivada neutra (pH 6-7. La tierra ácida reactivada, usada al 2 % consiguió una mayor reducción del color del aceite de soja, que una misma dosis de tierra virgen (pH 3. Ambas tierras reactivadas redujeron el índice de peróxidos, hierro, dienos conjugados y jabón de los aceites, mientras que hicieron aumentar la acidez y los trienos conjugados. Además, estas tierras reactivadas determinaron mayores descensos en los periodos de inducción del aceite que la tierra virgen. Las tierras

  17. Color Recovery Effect of Different Bleaching Systems on a ...

    African Journals Online (AJOL)

    Composite samples were immersed in coffee and turnip juice for 1 week in each. One laser activated bleaching (LB) (Biolase Laserwhite*20) and three conventional bleaching systems (Ultradent Opalescence Boost 40% (OB), Ultradent Opalescence PF 15% home bleaching (HB), Crest 3D White [Whitening Mouthwash]) ...

  18. Annual coral bleaching and the long-term recovery capacity of coral

    Science.gov (United States)

    Schoepf, Verena; Grottoli, Andréa G.; Levas, Stephen J.; Aschaffenburg, Matthew D.; Baumann, Justin H.; Matsui, Yohei; Warner, Mark E.

    2015-01-01

    Mass bleaching events are predicted to occur annually later this century. Nevertheless, it remains unknown whether corals will be able to recover between annual bleaching events. Using a combined tank and field experiment, we simulated annual bleaching by exposing three Caribbean coral species (Porites divaricata, Porites astreoides and Orbicella faveolata) to elevated temperatures for 2.5 weeks in 2 consecutive years. The impact of annual bleaching stress on chlorophyll a, energy reserves, calcification, and tissue C and N isotopes was assessed immediately after the second bleaching and after both short- and long-term recovery on the reef (1.5 and 11 months, respectively). While P. divaricata and O. faveolata were able to recover from repeat bleaching within 1 year, P. astreoides experienced cumulative damage that prevented full recovery within this time frame, suggesting that repeat bleaching had diminished its recovery capacity. Specifically, P. astreoides was not able to recover protein and carbohydrate concentrations. As energy reserves promote bleaching resistance, failure to recover from annual bleaching within 1 year will likely result in the future demise of heat-sensitive coral species. PMID:26582020

  19. Coral Bleaching and Associated Mortality at Mayotte, Western Indian ...

    African Journals Online (AJOL)

    Mamoudzou 97600, Mayotte. Keywords: coral, bleaching, mortality, Mayotte, Western Indian Ocean. Abstract—Bleaching and associated coral mortality were assessed on fringing and barrier reefs on the north and east coasts of Mayotte from 1-24 May 2010. Major bleaching was encountered; nearly 80% of the corals were ...

  20. Characterization of Coronal Pulp Cells and Radicular Pulp Cells in Human Teeth.

    Science.gov (United States)

    Honda, Masaki; Sato, Momoko; Toriumi, Taku

    2017-09-01

    Dental pulp has garnered much attention as an easily accessible postnatal tissue source of high-quality mesenchymal stem cells (MSCs). Since the discovery of dental pulp stem cells (DPSCs) in permanent third molars, stem cells from human exfoliated deciduous teeth and from supernumerary teeth (mesiodentes) have been identified as a population distinct from DPSCs. Dental pulp is divided into 2 parts based on the developing stage: the coronal pulp and the radicular pulp. Root formation begins after the crown part is completed. We performed a sequential study to examine the differences between the characteristics of coronal pulp cells (CPCs) and radicular pulp cells (RPCs) from permanent teeth, mesiodentes, and deciduous teeth. Interestingly, although we have not obtained any data on the difference between CPCs and RPCs in permanent teeth, there are some differences between the characteristics of CPCs and RPCs from mesiodentes and deciduous teeth. The MSC characteristics differed between the RPCs and CPCs, and the reprogramming efficiency for the generation of induced pluripotent stem cells was greater in RPCs than in CPCs from deciduous teeth. The proportion of CD105 + cells in CPCs versus that in RPCs varied in mesiodentes but not in permanent teeth. The results indicate that the proportion of CD105 + cells is an effective means of characterizing dental pulp cells in mesiodentes. Taken together, the stem cells in deciduous and supernumerary teeth share many characteristics, such as a high proliferation rate and an immunophenotype similar to that of DPSCs. Thus, mesiodentes accidentally encountered on radiographs by the general dental practitioner might be useful for stem cell therapy. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.