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Sample records for cellulose pulp bleaching

  1. 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....

  2. BLEACHING EUCALYPTUS PULPS WITH SHORT SEQUENCES

    OpenAIRE

    Flaviana Reis Milagres; Jorge Luiz Colodette; Marcos Sousa Rabelo; Danila Morais de Carvalho

    2011-01-01

    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 d...

  3. THE STUDY ON TCF BLEACHING OF NS REED PULP

    Institute of Scientific and Technical Information of China (English)

    Meihong Niu; Shulan Shi; Jinghui Zhou; Yunzhan Zhang

    2004-01-01

    In this paper, we have researched TCF bleaching on reed pulp including oxygen delignification, oxygen delignification with H2O2 intensification and H2O2 bleaching. The results show that Op-P bleaching process on NS reed pulp is suitable and the brightness of bleached pulp is up to 82% ISO.

  4. THE STUDY ON TCF BLEACHING OF NS REED PULP

    Institute of Scientific and Technical Information of China (English)

    MeihongNiu; ShulanShi; JinghuiZhou; YunzhanZhang

    2004-01-01

    In this paper, we have researched TCF bleaching on reed pulp including oxygen delignification, oxygen delignification with H202 intensification and H2O2 bleaching. The results show that Op-P bleaching process on NS reed pulp is suitable and the brightness of bleached pulp is up to 82%ISO.

  5. Enzymes improve ECF bleaching of pulp

    Directory of Open Access Journals (Sweden)

    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.

  6. Enzymes improve ECF bleaching of pulp

    OpenAIRE

    Lachenal, D.; Bajpai, P. K.; S P Mishra; Sharma, N.; Anand, A; Bajpai, P.

    2006-01-01

    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...

  7. BLEACHING EUCALYPTUS PULPS WITH SHORT SEQUENCES

    Directory of Open Access Journals (Sweden)

    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.

  8. Nanocrystalline cellulose from aspen kraft pulp and its application in deinked pulp.

    Science.gov (United States)

    Xu, Qinghua; Gao, Yang; Qin, Menghua; Wu, Kaili; Fu, Yingjuan; Zhao, Jian

    2013-09-01

    Nanocrystalline cellulose (NCC) isolated from bleached aspen kraft pulp was characterized, and its application as pulp strengthening additive and retention aid was investigated. Results showed that NCC with high crystallinity of more than 80% can be obtained using 64 wt% sulfuric acid. The structure of nanocrystalline cellulose is parallelepiped rod-like, and their cross-sectional dimension is in the nanometer range with a high aspect ratio. The formation of microparticle retention systems during the application of NCC together with cationic polyacrylamide and cationic starch in deinked pulp was able to further improve pulp retention and strength properties without negative influence on the drainage.

  9. EFFECT BLEACHING REAGENT ON THE QUALITY OF FLAX CELLULOSE

    OpenAIRE

    Дейкун, Ірина Михайлівна

    2015-01-01

    The paper studies the impact of bleaching chemicals such as chlorine dioxide, hydrogen peroxide and chlorine on the product yield, residual lignin content, a-cellulose, viscosity, ash content and whiteness of flax natron cellulose for chemical processing.It was found that one-step processing of flax pulp with chlorine dioxide consumption rate 0,3…0,5 % and with hydrogen peroxide consumption rate 2…3 % by weight of abs. dry cellulose is more effective than treatment with chlorine water at chlo...

  10. TCF bleaching sequence in kraft pulping of olive tree pruning residues.

    Science.gov (United States)

    Requejo, A; Rodríguez, A; Colodette, J L; Gomide, J L; Jiménez, L

    2012-08-01

    The aim of the present work was to find a suitable Kraft cooking process for olive tree pruning (OTP), in order to produce pulp of kappa number about 17. The Kraft pulp produced under optimized conditions showed a viscosity of 31.5 mPa·s and good physical, mechanical, and optical properties, which are suitable for paper production. The physical-mechanical and optical properties were measured before and after bleaching. Although the OTP pulp was bleached to 90.9% ISO brightness (kappapulp showed a brightness reversion equal to 1.3%. Furthermore, this bleached pulp did not need a high intensity of beating due to high drainability degree in the unbeaten pulp. So that, OTP is suggested as an interesting raw material for cellulosic pulp production because its properties are comparable to those of other agricultural residues, currently used in the paper industry.

  11. 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.

  12. Bleached dissolving pulps applying laccase treatments

    OpenAIRE

    Quintana, Elisabet; Valls Vidal, Cristina; Roncero Vivero, María Blanca

    2012-01-01

    A biobleaching sequence, using a laccase enzyme (Trametes Villosa) in combination with different mediators, was applied to softwood dissolving cellulose in order to study its bleaching efficiency and its potential in terms of kappa number, ISO brightness and viscosity. The tested mediators were classified as synthetic compounds such as HBT (1-hydroxybenzotriazole) and VA (violuric acid), and as natural compounds such as SA (syringaldehyde) and pCA (p-coumaric acid). The influence of the enzym...

  13. INFLUENCES OF BLAECHING ADDITIVES ON REED PULP FAST BLEACHING

    Institute of Scientific and Technical Information of China (English)

    Yanjun Tang; Bingyue Liu; Runan Yang; Zheng Lu

    2004-01-01

    The influences of bleaching additives on hypochlorite single-stage high temperature fast bleaching of neutral-sulfite reed pulp were studied. The influencing factors of bleaching velocity and result were as follows: the order and time of adding imide type additives, additives dosage, the dosage of NaOH and MgO used as buffer to turn up pH.

  14. REINFORCEMENT POTENTIAL OF BLEACHED SAWDUST KRAFT PULP IN DIFFERENT MECHANICAL PULP FURNISHES

    Directory of Open Access Journals (Sweden)

    Risto I. Korpinen

    2009-11-01

    Full Text Available Bleached unrefined and refined sawdust kraft pulps were added to bleached Norway spruce thermomechanical (TMP and pressurised groundwood (PWG pulps in different proportions. Handsheets were prepared and tested for physical properties. In addition, economic calculations were done to estimate the production costs of different bleached pulps in Finland. It was found that the addition of unrefined and refined sawdust kraft pulp improved drainability of the mechanical pulps. Tear strength of PGW furnishes was increased when either unrefined or refined sawdust pulp was added. Tear strength of TMP furnishes was not influenced when different sawdust kraft pulps were added. Up to 30 % of unrefined sawdust kraft pulp could be added and no significant negative effect was observed in TMP and PGW furnishes. On the other hand, when refined sawdust kraft pulp was added into the mechanical pulp furnishes, a clear improvement in the tensile strength was observed. According to the economic calculation the production cost of bleached sawdust kraft pulp is almost as low as the production cost of bleached mechanical pulp. We suggest that economically viable sawdust kraft pulp can be used as a substituent for expensive long fibre reinforcement kraft pulp in the production of mechanical pulp based papers.

  15. Dental pulp vascular permeability changes induced by dental bleaching

    OpenAIRE

    Cristiane da Costa; Sueli Patricia Harumi Miyagi; Marcelo dos Santos; Manoel Eduardo de Lima Machado; Márcia Martins Marques

    2012-01-01

    Aiming to compare the effect of different light sources for dental bleaching on vascular permeability of dental pulps, forty-eight incisors were used. The bleaching agent (35 % hydrogen peroxide) was activated by halogen light; LED (Light Emitting Diode) or LED, followed by laser phototherapy (LPT) (λ = 780 nm; 3 J/cm²). After the bleaching procedures, the animals received an intra-arterial dye injection and one hour later were sacrificed. The teeth were diaphanized and photographed. The...

  16. Dental pulp vascular permeability changes induced by dental bleaching

    Directory of Open Access Journals (Sweden)

    Cristiane da Costa

    2012-02-01

    Full Text Available Aiming to compare the effect of different light sources for dental bleaching on vascular permeability of dental pulps, forty-eight incisors were used. The bleaching agent (35 % hydrogen peroxide was activated by halogen light; LED (Light Emitting Diode or LED, followed by laser phototherapy (LPT (λ = 780 nm; 3 J/cm². After the bleaching procedures, the animals received an intra-arterial dye injection and one hour later were sacrificed. The teeth were diaphanized and photographed. The amount of blue stain content of each dental pulp was quantified using a computer imaging program. The data was statistically compared (p < 0.05. The results showed a significant higher (p < 0.01 dye content in the groups bleached with halogen light, compared with the control, LED and LED plus LPT groups. Thus, tooth bleaching activated by LED or LED plus LPT induces lesser resulted in increased vascular permeability than halogen light.

  17. SYNERGISTIC EFFECTS BETWEEN BIRCH CHEMICAL MECHANICAL PULPS AND ASPEN BLEACHED KRAFT PULP

    Institute of Scientific and Technical Information of China (English)

    Eric C. Xu; Yajun Zhou

    2004-01-01

    In this investigation, two different grades of birch chemical mechanical (P-RC APMP) pulps and aspen market bleached kraft pulp were compared by low consistency refining of the pulps separately and in different combinations. In addition, the separately refined pulps were also combined to compare with the pulps from the co-refined pulp blend. The results showed that in both cases there were synergistic effects between the two types of pulps: adding the birch P-RC APMP pulp to the aspen kraft pulp improved pulp properties, and the resultant pulp blends had a higher fiber bonding strength (tensile and tensile energy absorption) than the sum of weighted contributions from the individual components. Understanding this synergistic effect between chemical mechanical (P-RC APMP) and kraft pulps can help to improve their applications and performances in various papermaking processes.The results also showed that introducing, at least up to certain percentage of, the birch P-RC APMP pulp into the aspen bleached kraft pulp not only improves optical and bulk properties, but also maintains or improves tensile strength, even though the P-RC APMP pulp used has lower tensile than the kraft pulp.

  18. SYNERGISTIC EFFECTS BETWEEN BIRCH CHEMICAL MECHANICAL PULPS AND ASPEN BLEACHED KRAFT PULP

    Institute of Scientific and Technical Information of China (English)

    EricC.Xu; YajunZhou

    2004-01-01

    In this investigation, two different grades of birch chemical mechanical (P-RC APMP) pulps and aspen market bleached kraft pulp were compared by low consistency refining of the pulps separately and in different combinations. In addition, the separately refined pulps were also combined to compare with the pulps from the co-refined pulp blend. The results showed that in both cases there were synergistic effects between the two types of pulps: adding the birch P-RC APMP pulp to the aspen kraft pulp improved pulp properties, and the resultant pulp blends had a higher fiber bonding strength (tensile and tensile energy absorption) than the sum of weighted contributions from the individual components. Understanding this synergistic effect between chemical mechanical (P-RC APMP) and kraft pulps can help to improve their applications and performances in various papermaking processes. The results also showed that introducing, at least up to certain percentage of, the birch P-RC APMP pulp into the aspen bleached kraft pulp not only improves optical and bulk properties, but also maintains or improves tensile strength, even though the P-RC APMP pulp used has lower tensile than the kraft pulp.

  19. SUGARCANE BAGASSE PULPING AND BLEACHING: THERMAL AND CHEMICAL CHARACTERIZATION

    Directory of Open Access Journals (Sweden)

    Paulo Henrique Fernandes Pereira

    2011-05-01

    Full Text Available Cellulose fibers were isolated from sugarcane bagasse in three stages. Initially sugarcane bagasse was subjected to a pre-treatment process with hydrolyzed acid to eliminate hemicellulose. Whole cellulosic fibers thus obtained were then subjected to a two-stage delignification process and finally to a bleaching process. The chemical structure of the resulting cellulose fibers was studied by Fourier Transform Infrared (FTIR spectroscopy. Scanning Electron Microscopy (SEM and X-ray diffraction (XRD were used to analyze the effects of hydrolysis, delignification, and bleaching on the structure of the fibers. Two different thermal analysis techniques were used to study the bleaching cellulose fibers. These techniques confirmed that cellulose fibers were isolated from sugarcane bagasse. A future goal is to use these fibers as reinforcement elements in composites, organic-inorganic hybrid, and membranes for nanofiltration.

  20. MOLYBDENUM CATALYZED ACID PEROXIDE BLEACHING OF EUCALYPTUS KRAFT PULP

    OpenAIRE

    Marcos S. Rabelo; Jorge L. Colodette; Vera M. Sacon; Marcelo R. Silva; Marco A. B. Azevedo

    2008-01-01

    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 (NH4)6Mo7O24.4H2O, 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 eucalyp...

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

    OpenAIRE

    Kátia Maria Morais Eiras; Jorge Luiz Colodette; Vanessa Lopes Silva

    2009-01-01

    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 dioxi...

  2. Analysis of the effect of wash water reduction on bleached pulp characteristics.

    Science.gov (United States)

    Frigieri, Tânia Cristina; Ventorim, Gustavo; Savi, Antônio Francisco; Favaro, Jaqueline Silveira Comelato

    2015-01-01

    The main objective of this study was to analyse cost reduction by reducing the use of fresh water in the cellulose bleaching process and to make it easier to obtain water in a closed circuit. Eucalyptus oxygen delignified industrial pulp was used. The pulp was bleached 10 times in the D(E+P)DP sequence in the same conditions. Counter current washing was used in the bleaching stages, and each sequence was carried out with different wash factors: 9, 6, 3, and 0 m³ of distilled water/ton of oven dry pulp. The goal was to reach brightness of 92±0.5% ISO. The results showed that there was a chemical oxygen demand (COD) increase and brightness reversion, but the kappa number and viscosity did not change. The apparent colour was increased by increasing COD in the effluent during the cycles and by decreasing the wash water. Up to 3 m³/t of water was tolerable and even recommended to wash pulp. Nine cubic metre per tonne of fresh water is most commonly used in the industry, so water savings make the implementation of the process possible.

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

    Directory of Open Access Journals (Sweden)

    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.

  4. INCLUSION OF A PRESSURIZED ACIDOLYSIS STAGE IN CHEMICAL PULP BLEACHING

    Directory of Open Access Journals (Sweden)

    Samar K. Bose

    2011-02-01

    Full Text Available Hardwood soda-AQ pulps are believed to be rich in benzyl sugar ethers (BSE that can be partially cleaved by aqueous acidic treatments. The aim of this investigation was to evaluate the effect of acidolysis on final bleached brightness for kraft and soda-AQ (SAQ hardwood pulps. The increase in final brightness due to acidolysis at 110 °C was twice as high for a eucalyptus SAQ pulp as compared to the kraft pulp. An oxygen delignified maple C-SAQ pulp (carbonate pre-treated SAQ was acidolyzed at 120 °C and pH 2.6 for 30 min. When 1.60% ClO2 + 0.25% H2O2 on pulp was used in DEPD final bleaching of the control sample a brightness of 91.5% was achieved. When only 1.00% ClO2 + 0.25% H2O2 on pulp was used for the acidolyzed sample a brightness of 92.0% was attained. Analyses of the maple pulp after the acidolysis showed no major change in lignin content, brightness, or pulp yield. The minor changes suggest that a facile reaction such as benzyl ether cleavage was responsible for the improved bleachability. Preliminary research involving a lignin model compound and commercial birch xylan showed that lignin-carbohydrate condensation products were generated under SAQ cooking conditions. Furthermore, a fraction of these lignin-carbohydrate moieties were subsequently cleaved by acidolysis at pH 2.5 and 105 °C.

  5. MOLYBDENUM CATALYZED ACID PEROXIDE BLEACHING OF EUCALYPTUS KRAFT PULP

    Directory of Open Access Journals (Sweden)

    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.

  6. Detection of Chlorophenolic Compounds in Bleaching Effluents of Chemical Pulps

    Institute of Scientific and Technical Information of China (English)

    Chhaya Sharma; S.Mohanty; S.Kumar; N.J.Rao; li qian

    2008-01-01

    Laboratory bleaching effluents from the chlorination and caustic extraction stages of mixed wood kraft pulp processing have been analysed both qualitatively and quantitatively for various chlorophenolics by using GC.A number of chlorinated derivaties of phenols,catechols,guaiacols and syringaldehydes have been detected and their concentrations are estimated.The results are compared with that of different agriculture residue / hardwood pulps,which were reported in literature.The concentrations of various compounds detected have also been compared with their reported 96LC50 values.

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

    Directory of Open Access Journals (Sweden)

    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.

  8. Hemicellulases in the bleaching and characterisation of kraft pulps. Doctoral thesis

    Energy Technology Data Exchange (ETDEWEB)

    Suurnaekki, A.

    1996-03-01

    Xylanase-aided bleaching of kraft pulps is the major industrial application of hemicellulases in pulp processing. In addition to process aids, hemicellulases have recently also been shown to be promising tools in fibre analytics. In this work, the role of xylanase and mannanase pretreatments in the bleaching of softwood pulps produced by different sulphate cooking methods was studied. In addition, the action of hemicellulases in kraft fibres was characterized and exploited in the analysis of the suface composition of kraft pulps.

  9. Papermaking fibers from giant reed (Arundo donax L. by advanced ecologically friendly pulping and bleaching technologies

    Directory of Open Access Journals (Sweden)

    Pereira, H.

    2006-07-01

    Full Text Available The anatomical structure and chemical composition of the stem-wall material of giant reed is considered from the viewpoint of raw material characterization for industrial fiber production. The effect of stem morphology (nodes and internodes on pulping results and general pulp properties is discussed. The advantages of application of modern organic solvent based (organosolv pulping technologies to giant reed are shown in comparison with the conventional (kraft method. The conditions optimization for Ethanol-Alkali pulping (a selected organosolv pulping process is given, and the chemical kinetics of the principal macromolecular components during ethanol-alkali pulping is described. The bleachability of organosolv pulps by short totally chlorine free (TCF bleaching sequences using hydrogen peroxide and ozone as the active bleaching chemicals without pulp pre-delignification is examined and compared with kraft pulps. The enzymatic pre-treatment of reed organosolv pulps by commercial xylanase preparation is considered as a possibility toward the improvement of pulp bleachability.

  10. Improvement of bleached wheat straw pulp properties by using aspen high-yield pulp.

    Science.gov (United States)

    Zhang, Hongjie; Li, Jianguo; Hu, Huiren; He, Zhibin; Ni, Yonghao

    2012-09-01

    The bleached wheat straw pulp (BWSP) accounts for about 25% of the virgin fiber supply in the Chinese Pulp and Paper Industry. As a non-wood chemical pulp, BWSP is known to have low bulk, low light scattering coefficient and poor drainage due to its high content of parenchyma cells. In this study, a high-quality aspen high-yield pulp (HYP) was used to improve the BWSP properties at the laboratory scale. The results indicate that adding 5-20% aspen HYP into unrefined or refined BWSP can minimize many of the drawbacks associated with the BWSP: improving its drainage, bulk, light scattering coefficient and opacity. The addition of a small amount (up to 20%) of aspen HYP can also significantly increase the tear index of BWSP with only a slight decrease of the tensile index.

  11. WOOD BASIC DENSITY EFFECT OF Eucalyptus grandis x Eucalyptus urophylla CLONES ON BLEACHED PULP QUALITY

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    Sheila Rodrigues dos Santos

    2010-08-01

    Full Text Available The study analyzed the wood basic density effect in two Eucalyptus grandis x Eucalyptus urophylla hybrid clones (440 kg/m3 e 508 kg/m3 on bleached pulp quality (fiber dimensions and physical-mechanical properties. The woods performance on pulping, bleaching and beating results were analyzed. The Kraft pulping was carried out in forced circulation digester in order to obtain 17±1 kappa number targets. The pulps were bleached to 90±1 using delignification oxygen and D0EOPD1 bleaching sequence. Bleached pulp of low basic density clone showed, significantly, lowest revolutions number in the PFI mill to reach tensile index of 70 N.m/g, low Schopper Riegler degree and generated sheets with higher values to bulk and opacity. These characteristics and properties allow concluding that bleached pulp of low basic density clone was the most indicated to produce printing and writing sheets. The bleached pulp of high basic density clone showed higher values of bulk and capillarity Klemm and lower water retention value when analyzed without beating. The bleached pulp of high basic density clone showed more favorable characteristics to the production of tissue papers.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  14. USING Mg(OH2 IN PEROXIDE BLEACHING OF WHEAT STRAW SODA-AQ PULP

    Directory of Open Access Journals (Sweden)

    Yanlan Liu

    2011-04-01

    Full Text Available The peroxide bleaching of high yield pulps from wood with Mg(OH2 has been developing recently in the pulp and paper industry. However, there is still a lack of data on the application of Mg(OH2 in peroxide bleaching of non-wood fibres. In this work, our purpose was to study the effect of Mg(OH2 on peroxide bleaching of wheat straw soda-AQ pulp. The results showed that Mg(OH2 significantly improved peroxide bleaching efficiency (expressed as the ratio between the brightness gain and the H2O2 consumption and selectivity (expressed as the ratio between the brightness gain and the viscosity losses of wheat straw soda-AQ pulp. The brightness, viscosity, and yield of bleached pulp can be significantly enhanced by increasing the replacement ratio of Mg(OH2. However, at 100% replacement of NaOH with Mg(OH2, the brightness of bleached pulp was much lower than that of the bleached pulp with NaOH as the sole alkaline source. When 24 to 73% of the NaOH was replaced with Mg(OH2, the COD of the bleaching filtrate was 11 to 38% lower than that of the NaOH as the sole alkaline source. The lower solubility and alkalinity of Mg(OH2, as well as the reduction of Cu ion content in bleached pulp were proposed as accounting for the favorable effect of Mg(OH2 on peroxide bleaching of wheat straw soda-AQ pulp.

  15. MODIFIED OPAL:A NOVEL STABILIZER FOR HYDROGEN PEROXIDE BLEACHING OF PULPS

    Institute of Scientific and Technical Information of China (English)

    Xueren Qian; Xianhui An; Wenbo Liu; Gang Yu; Zhanqian Song

    2004-01-01

    The possibility of modified opal as the stabilizer of hydrogen peroxide bleaching was investigated. The results showed that the modified opal in place of sodium silicate as the stabilizer of hydrogen peroxide bleaching is feasible. At the same dosage, above 3% ISO can be increased for both wheat straw pulp and deinked pulp. The stabilizing ability of the modified opal to hydrogen peroxide bleaching of pulp is improved markedly. It is favorable for bleaching to increase temperature and time within a permissive extent. The suitable process conditions are 10% of pulp consistency, 3% of hydrogen peroxide, 1.5% of sodium hydroxide, 3% of the modified opal, 70℃ and 60 min when the modified opal is used as the stabilizer of hydrogen peroxide bleaching. At these conditions, the brightness gain can reach about 16% ISO for wheat straw pulp. In addition, it is favorable for bleaching to add a little magnesium sulfate when the modified opal is used as the stabilizer of hydrogen peroxide bleaching, the brightness of pulp can increase I%ISO if0.05% of magnesium sulfate is added. The cost analysis indicated that the modified opal is superior to sodium silicate as the stabilizer of hydrogen peroxide bleaching in economical aspect and has further the potential of market development.

  16. EFFECT OF LAST STAGE BLEACHING WITH PERACETIC ACID ON BRIGHTNESS DEVELOPMENT AND PROPERTIES OF EUCALYPTUS PULP

    Directory of Open Access Journals (Sweden)

    Denise P. Barros

    2010-05-01

    Full Text Available Investigation of last stage bleaching with peracetic acid is the main subject of this paper. Proper conditions were established to apply peracetic acid as the last bleaching stage of the D(EpD/Paa, DHT(EpD/Paa, A/D(EpD/Paa, DHT/Q(POPaa and Z/ED/Paa sequences. In addition, the impact of last stage bleaching with Paa on pulp refinability and strength properties was determined. Peracetic acid was consumed relatively fast when applied as the last stage of ECF bleaching sequences. A reaction time of 120 min at 75 oC and pH 5.0 is seemingly adequate regardless of the Paa dose, in the range of 1-5 kg/odt pulp and bleaching sequence. The optimum dose of Paa depends upon the sequence under investigation. In general the Paa application as last bleaching stage caused slight decrease in pulp viscosity, kappa number and HexA content but had no significant effect on pulp reversion and L*a*b* coordinates. The refinability and bonding strength properties of the pulps bleached with the sequences DHT(EpDD and DHT(EpD/Paa were quite similar when the pH of the last bleaching stage of both sequences were near 5. These properties improved slightly when Paa bleaching pH was raised to 8.5.

  17. In-office bleaching effects on the pulp flow and tooth sensitivity - case series.

    Science.gov (United States)

    Cartagena, Andrés Felipe; Parreiras, Sibelli Olivieri; Loguercio, Alessandro Dourado; Reis, Alessandra; Campanha, Nara Hellen

    2015-01-01

    Laser Doppler flowmetry (LDF) is a noninvasive method capable of evaluating variations in pulp blood flow (PBF) and pulp vitality. This method has thus far not been used to assess changes in blood flow after in-office bleaching. The aim of this case series report was to measure changes in PBF by LDF in the upper central incisor of three patients submitted to in-office bleaching. The buccal surfaces of the upper arch were bleached with a single session of 35% hydrogen peroxide gel with three 15-min applications. The color was recorded using a value-oriented Vita shade guide before in-office bleaching and one week after the procedure. The tooth sensitivity (TS) in a verbal scale was reported, and PBF was assessed by LDF before, immediately, and one week after the bleaching session. The lower arch was submitted to dental bleaching but not used for data assessment. A whitening degree of 3 to 4 shade guide units was detected. All participants experienced moderate to considerable TS after the procedure. The PBF readings reduced 20% to 40% immediately after bleaching. One week post-bleaching, TS and PBF were shown to be equal to baseline values. A reversible decrease of PBF was detected immediately after bleaching, which recovered to the baseline values or showed a slight increase sooner than one week post-bleaching. The LDF method allows detection of pulp blood changes in teeth submitted to in-office bleaching, but further studies are still required.

  18. In-office bleaching effects on the pulp flow and tooth sensitivity – case series

    Directory of Open Access Journals (Sweden)

    Andrés Felipe CARTAGENA

    2015-01-01

    Full Text Available Laser Doppler flowmetry (LDF is a noninvasive method capable of evaluating variations in pulp blood flow (PBF and pulp vitality. This method has thus far not been used to assess changes in blood flow after in-office bleaching. The aim of this case series report was to measure changes in PBF by LDF in the upper central incisor of three patients submitted to in-office bleaching. The buccal surfaces of the upper arch were bleached with a single session of 35% hydrogen peroxide gel with three 15-min applications. The color was recorded using a value-oriented Vita shade guide before in-office bleaching and one week after the procedure. The tooth sensitivity (TS in a verbal scale was reported, and PBF was assessed by LDF before, immediately, and one week after the bleaching session. The lower arch was submitted to dental bleaching but not used for data assessment. A whitening degree of 3 to 4 shade guide units was detected. All participants experienced moderate to considerable TS after the procedure. The PBF readings reduced 20% to 40% immediately after bleaching. One week post-bleaching, TS and PBF were shown to be equal to baseline values. A reversible decrease of PBF was detected immediately after bleaching, which recovered to the baseline values or showed a slight increase sooner than one week post-bleaching. The LDF method allows detection of pulp blood changes in teeth submitted to in-office bleaching, but further studies are still required.

  19. PRESENCE OF HARDWOOD CHIPS AND ITS IMPACT ON PULP STRENGTH PROPERTIES IN THE PRODUCTION OF BLEACHED SOFTWOOD KRAFT PULP

    Directory of Open Access Journals (Sweden)

    Zhibin He

    2010-11-01

    Full Text Available The effect of hardwood admixture (15-25% birch or aspen in kraft cooking on the strength properties of the fully bleached pulp was investigated. Results obtained from both lab- and mill-processed ECF bleached pulps showed that adding 15-25% birch or aspen to the production of fully bleached softwood kraft pulp had a minor effect on the strength properties. No significant effect was observed for the hardwood admixture on the apparent density over a wide range of breaking length. Under the conditions studied, the results showed that pulping of mixed softwood/hardwood chips (chip blending resulted in overall better strength properties than the pulp blending at a given freeness. It was hypothesized that the softwood fibers would be cooked to a higher kappa number in the cooking of mixed softwood/hardwood chips for the same target kappa number, thus having higher fiber strength due to higher pulp viscosity and preservation of the hemicellulose. This was supported by the results from zero-span tensile strength of the long fiber fraction of the samples from chip blending and pulp blending. The implication is that some softwood kraft pulp mills can add up to 25% of hardwood chips to the kraft cooking of softwood chips without significantly affecting the overall pulp strength properties.

  20. Biological evaluation of nanosilver incorporated cellulose pulp for hygiene products.

    Science.gov (United States)

    Kavitha Sankar, P C; Ramakrishnan, Reshmi; Rosemary, M J

    2016-04-01

    Cellulose pulp has a visible market share in personal hygiene products such as sanitary napkins and baby diapers. However it offers good surface for growth of microorganisms. Huge amount of research is going on in developing hygiene products that do not initiate microbial growth. The objective of the present work is to produce antibacterial cellulose pulp by depositing silver nanopowder on the cellulose fiber. The silver nanoparticles used were of less than 100 nm in size and were characterised using transmission electron microscopy and X-ray powder diffraction studies. Antibacterial activity of the functionalized cellulose pulp was proved by JIS L 1902 method. The in-vitro cytotoxicity, in-vivo vaginal irritation and intracutaneous reactivity studies were done with silver nanopowder incorporated cellulose pulp for introducing a new value added product to the market. Cytotoxicity evaluation suggested that the silver nanoparticle incorporated cellulose pulp is non-cytotoxic. No irritation and skin sensitization were identified in animals tested with specific extracts prepared from the test material in the in-vivo experiments. The results indicated that the silver nanopowder incorporated cellulose pulp meets the requirements of the standard practices recommended for evaluating the biological reactivity and has good biocompatibility, hence can be classified as a safe hygiene product. PMID:26838891

  1. Effects of Ethanol Pulping on the Length of Bamboo Cellulose

    Institute of Scientific and Technical Information of China (English)

    Tao Yang; Liao Junhe; Luo Xuegang

    2006-01-01

    On the conditions of different ethanol concentration, acids and catalyzers, the effects of ethanol pulping on the cellulose length of bamboo were studied. The results indicates that ethanol pulping has remarkable effects on the length of cellulose, which is clearly reduced with adding ethanol and acid. The margin of length of cellulose become smaller with the increase of the catalyzer. When the ethanol concentration was 70%, the concentration of acid was 0.3% and some NaOH was used as catalyzer, the length of cellulose was the longest.

  2. Strength enhancement of fiber network by carboxymethyl cellulose during oxygen delignification of kraft pulp

    Directory of Open Access Journals (Sweden)

    Eero Kontturi

    2008-02-01

    Full Text Available Sorption of carboxymethyl cellulose (CMC on the fiber surface was applied during oxygen delignification to enhance the strength properties of softwood kraft pulp. Unlike many previous efforts, the focus was not set on the improvement of selectivity of oxygen delignification, i.e. retaining stable viscosity vs. decreasing kappa number. Instead, without an improved selectivity, handsheets from CMC-treated fibers exhibited a 15% improvement in tensile index and 25% improvement in tear index after a full bleaching sequence in comparison to the untreated reference pulp. Since it is demonstrated that the CMC addition can be incorporated as an integral step in the fiberline process, the method offers an effortless and viable option to produce pulp resulting in stronger paper products.

  3. Structural modifications of flax and sisal lignin during the pulping and bleaching processes

    OpenAIRE

    Marques, Gisela; Gutiérrez Suárez, Ana; Nieto Garrido, Lidia; Jiménez-Barbero, Jesús; Martínez, Ángel T.; Río Andrade, José Carlos del

    2011-01-01

    We have studied the structural modifications of the lignin of flax and sisal during the pulping (soda/AQ) and bleaching (TCF and ECF) processes. The residual lignins were isolated by acidolysis and subsequently characterized by Py-GC/MS and 2D-NMR. Flax residual lignins have a predominance of G-lignin and low amounts of S-lignin units in the unbleached pulp, which are also present in similar abundances in the residual lignin after TCF bleaching. After ECF bleaching, lignin was still present, ...

  4. MODIFIED OPAL: A NOVEL STABILIZER FOR HYDROGEN PEROXIDE BLEACHING OF PULPS

    Institute of Scientific and Technical Information of China (English)

    XuerenQian; XianhuiAn; WenboLiu; GangYu; ZhanqianSong

    2004-01-01

    The possibility of modified opal as the stabilizer ofhydrogen peroxide bleaching was investigated. Theresults showed that the modified opal in place ofsodium silicate as the stabilizer of hydrogen peroxidebleaching is feasible. At the same dosage, above 3%ISO can be increased for both wheat straw pulp anddeinked pulp. The stabilizing ability of the modifiedopal to hydrogen peroxide bleaching of pulp isimproved markedly. It is favorable for bleaching toincrease temperature and time within a permissiveextent. The suitable process conditions are I0% ofpulp consistency, 3% of hydrogen peroxide, 1.5% ofsodium hydroxide, 3% of the modified opal, 70~"and 60 min when the modified opal is used as thestabilizer of hydrogen peroxide bleaching. At theseconditions, the brightness gain can reach about 16%ISO for wheat straw pulp. In addition, it is favorablefor bleaching to add a little magnesium sulfate whenthe modified opal is used as the stabilizer ofhydrogen peroxide bleaching, the brightness of pulpcan increase 1%ISO if0.05% of magnesium sulfate isadded. The cost analysis indicated that the modifiedopal is superior to sodium silicate as the stabilizer ofhydrogen peroxide bleaching in economical aspectand has further the potential of market development.

  5. CHLORINE DIOXIDE BLEACHING OF SODA-ANTHRAQUINONE JUTE PULP TO A VERY HIGH BRIGHTNESS

    Directory of Open Access Journals (Sweden)

    M. Sarwar Jahan

    2010-05-01

    Full Text Available Bleaching of soda-anthraquinone jute pulp by chlorine dioxide (ClO2 was studied to reach a target brightness of above 88% for the purpose of using less bleaching chemicals. The performance of either chlorine dioxide or peroxide in the final bleaching to boost brightness was also studied. The experimental results revealed that the final brightness depended on ClO2 charge in the Do and D1 stages. The brightness reversion was lower when the final stage brightening was done by peroxide. The use of Mg(OH2 in the D1 and D2 stages improved the final brightness due to the formation of less chlorate and chlorite during the Mg(OH2- based ClO2 brightening stages. The strength properties of pulp bleached by peroxide in the final stage was slightly better than that from ClO2 as the final ClO2 bleaching stage.

  6. HYDROGEN PEROXIDE BLEACHING OF HARDWOOD KRAFT PULP WITH ADSORBED BIRCH XYLAN AND ITS EFFECT ON PAPER PROPERTIES

    Directory of Open Access Journals (Sweden)

    Hyejung Youn

    2011-02-01

    Full Text Available The adsorption of xylan on pulp fibers improves the strength properties of paper. However, the optical properties are decreased significantly. The objective of our research was to bleach hardwood kraft pulp with adsorbed birch xylan by hydrogen peroxide and study the effect of bleaching parameters on paper properties. The bleaching parameters studied included bleaching temperature, time, initial pH as well as MgSO4 dosage. The optical properties (whiteness, brightness, opacity and physical properties (tensile index, tearing index, bulk of handsheets made from the pulp bleached with different process variables were measured. The results showed that better optical properties were obtained with higher bleaching temperature, longer bleaching time, and more MgSO4 dosage. Bleaching from an initial pH of 11 provided the highest brightness value. On the other hand, strength properties were improved with decreasing of the bleaching temperature, and increasing the initial pH and MgSO4 dosage. The relationship between strength properties and bleaching time varied depending on bleaching temperature. According to the results, both good mechanical properties and optical properties could be achieved when the operating parameters were controlled properly. Therefore hydrogen peroxide bleaching was proved to be a suitable method for bleaching hardwood kraft pulp with adsorption of birch xylan.

  7. ALKALI DARKENING AND ITS RELATIONSHIP TO PEROXIDE BLEACHING OF MECHANICAL PULP

    Institute of Scientific and Technical Information of China (English)

    Zhibin He; Yonghao Ni; Eric Zhang

    2004-01-01

    The effect of alkalinity, transition metals and oxygen on alkali darkening of mechanical pulp, and its relations to subsequent peroxide bleaching were investigated. The chromophores generated under mild conditions of an alkaline treatment can be destroyed in a subsequent peroxide stage.Peroxide-resistant chromophores are generated only under severe conditions. The results also show that a short alkaline pretreatment can improve the performance of a peroxide bleaching stage.

  8. ALKALI DARKENING AND ITS RELATIONSHIP TO PEROXIDE BLEACHING OF MECHANICAL PULP

    Institute of Scientific and Technical Information of China (English)

    ZhibinHe; Yon2haoNi; EricZhang_

    2004-01-01

    The effect of alkalinity, transition metals and oxygen on alkali darkening of mechanical pulp, and its relations to subsequent peroxide bleaching were investigated. The chromophores generated under mild conditions of an alkaline treatment can be destroyed in a subsequent peroxide stage. Peroxide-resistant chromophores are generated only under severe conditions. The results also show that a short alkaline pretreatment can improve the performance of a peroxide bleaching stage.

  9. CHLORINE DIOXIDE BLEACHING OF SODA-ANTHRAQUINONE JUTE PULP TO A VERY HIGH BRIGHTNESS

    OpenAIRE

    M. Sarwar Jahan; Yonghao Ni,; Zhibin He

    2010-01-01

    Bleaching of soda-anthraquinone jute pulp by chlorine dioxide (ClO2) was studied to reach a target brightness of above 88% for the purpose of using less bleaching chemicals. The performance of either chlorine dioxide or peroxide in the final bleaching to boost brightness was also studied. The experimental results revealed that the final brightness depended on ClO2 charge in the Do and D1 stages. The brightness reversion was lower when the final stage brightening was done by peroxide. The use ...

  10. Integrating a xylanase treatment into an industrial-type sequence for eucalyptus kraft pulp bleaching

    OpenAIRE

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

    2012-01-01

    The influence of a treatment with two commercial xylanases on pulp and effluents obtained after the bleaching stages in the OXAZDP (O, oxygen stage; X, xylanase treatment; A, acid stage; Z, ozone stage; D, chlorine dioxide stage; P, hydrogen peroxide stage) sequence was studied. Also, the potential saving in chlorine dioxide was assessed. The enzyme treatment was performed on pulp containing some black liquor since the operating conditions were close to the conditions used in the storage towe...

  11. 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.

  12. Overproduction of the Aspergillus niger feruloyl esterase for pulp bleaching application

    NARCIS (Netherlands)

    Record, E.; Asther, M.; Sigoillot, C.; Pagès, S.; Punt, P.J.; Delattre, M.; Haon, M.; Hondel, C.A.M.J.J. van den; Sigoillot, J.C.; Lesage-Meessen, L.; Asther, M.

    2003-01-01

    A well-known industrial fungus for enzyme production, Aspergillus niger, was selected to produce the feruloyl esterase FAEA by homologous overexpression for pulp bleaching application. The gpd gene promoter was used to drive FAEA expression. Changing the nature and concentration of the carbon source

  13. EFFECT OF BIRCH KRAFT PULP PRIMARY FINES ON BLEACHING AND SHEET PROPERTIES

    Directory of Open Access Journals (Sweden)

    Sari Anneli Asikainen

    2010-08-01

    Full Text Available By removing the primary fines from an oxygen-delignified mill birch pulp, a fiber fraction was obtained having low metals content and no extractives. After DEDeD bleaching the fiber fraction had somewhat higher brightness and better brightness stability than the birch pulp containing the primary fines. The fines fraction was enriched with lignin, extractives, xylan, and metals. Bleaching the fines fraction in a QQP sequence did not affect the extractives, whereas a ZeQP sequence clearly reduced the extractives content. In a biorefinery concept, the fines fraction could be utilized as a source of xylan, fatty acids, sterols, and betulinol. Another possibility is to use the fines fraction unbleached or separately bleached as a bonding material in various fiber furnishes.

  14. 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.

  15. In vitro study of the pulp chamber temperature rise during light-activated bleaching

    Directory of Open Access Journals (Sweden)

    Thaise Graciele Carrasco

    2008-10-01

    Full Text Available This study evaluated in vitro the pulp chamber temperature rise induced by the light-activated dental bleaching technique using different light sources. The root portions of 78 extracted sound human mandibular incisors were sectioned approximately 2 mm below the cementoenamel junction. The root cavities of the crowns were enlarged to facilitate the correct placing of the sensor into the pulp chamber. Half of specimens (n=39 was assigned to receive a 35% hydrogen peroxide gel on the buccal surface and the other halt (n=39 not to receive the bleaching agent. Three groups (n=13 were formed for each condition (bleach or no bleach according to the use of 3 light sources recommended for dental bleaching: a light-emitting diode (LEDlaser system, a LED unit and a conventional halogen light. The light sources were positioned perpendicular to the buccal surface at a distance of 5 mm and activated during 30 s. The differences between the initial and the highest temperature readings for each specimen were obtained, and, from the temperature changes, the means for each specimen and each group were calculated. The values of temperature rise were compared using Kruskal-Wallis test at 1% significance level. Temperature rise varied significantly depending on the light-curing unit, with statistically significant differences (p0.01. When the bleaching agent was applied, there were significant differences among groups (p<0.01: halogen light induced the highest temperature rise (1.41±0.64ºC, and LED-laser system the lowest (0.33±0.12ºC; however, there was no difference between LED-laser system and LED unit (0.44±0.11ºC. LED and LED-laser system did not differ significantly from each other regardless the temperature rise occurred with or without bleaching agent application. It may be concluded that during light-activated tooth bleaching, with or without the bleaching agent, halogen light promoted higher pulp chamber temperature rise than LED unit and LED

  16. Controlling bleached kraft pulp costs: a predictive modelling approach

    Energy Technology Data Exchange (ETDEWEB)

    Schroderus, S.K.

    1988-07-01

    A mathematical model is described which simulates the operation of a bleached kraft paper mill. The model can be used to analyze a wide range of operating conditions and mill configurations. It is structured into the following functional blocks: assignment of process parameters; cooking and brown stock washing; bleaching, evaporation and calculation of black liquor heating value; recovery boiler and recausticizing; secondary heat balance; and generation of heat and electrical power. Computer programs have been developed using the model, usable on inexpensive personal computers, which enable calculation of stream variables, consumption of wood, chemicals, and energy, and operating costs. Examples of model use are presented, calculated for a hypothetical mill featuring a continuous digester and a low-odor type recovery boiler. These examples illustrate the effect of operating conditions on operating costs. 24 refs., 7 figs.

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

    OpenAIRE

    Robisnéa A. Ribeiro; Fernando J. B. Gomes; José N. Floriani; Renato A. P. Damásio; Iara F. Demuner; Jorge L. Colodette

    2014-01-01

    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 expla...

  18. 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.

  19. Removal of hexenuronic acid by xylanase to reduce adsorbable organic halides formation in chlorine dioxide bleaching of bagasse pulp.

    Science.gov (United States)

    Nie, Shuangxi; Wang, Shuangfei; Qin, Chengrong; Yao, Shuangquan; Ebonka, Johnbull Friday; Song, Xueping; Li, Kecheng

    2015-11-01

    Xylanase-aided chlorine dioxide bleaching of bagasse pulp was investigated. The pulp was pretreated with xylanase and followed a chlorine dioxide bleaching stage. The ATR-FTIR and XPS were employed to determine the surface chemistry of the control pulp, xylanase treated and chlorine dioxide treated pulps. The hexenuronic acid (HexA) could obviously be reduced after xylanase pretreatment, and the adsorbable organic halides (AOX) were reduced after chlorine dioxide bleaching. Compared to the control pulp, AOX could be reduced by 21.4-26.6% with xylanase treatment. Chlorine dioxide demand could be reduced by 12.5-22% to achieve the same brightness. The ATR-FTIR and XPS results showed that lignin and hemicellulose (mainly HexA) were the main source for AOX formation. Xylanase pretreatment could remove HexA and expose more lignin, which decreased the chlorine dioxide demand and thus reduced formation of AOX. PMID:26263004

  20. 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.

  1. Optimizing Extraction of Cellulose and Synthesizing Pharmaceutical Grade Carboxymethyl Sago Cellulose from Malaysian Sago Pulp

    Directory of Open Access Journals (Sweden)

    Anand Kumar Veeramachineni

    2016-06-01

    Full Text Available Sago biomass is an agro-industrial waste produced in large quantities, mainly in the Asia-Pacific region and in particular South-East Asia. This work focuses on using sago biomass to obtain cellulose as the raw material, through chemical processing using acid hydrolysis, alkaline extraction, chlorination and bleaching, finally converting the material to pharmaceutical grade carboxymethyl sago cellulose (CMSC by carboxymethylation. The cellulose was evaluated using Thermogravimetric Analysis (TGA, Infrared Spectroscopy (FTIR, X-Ray Diffraction (XRD, Differential Scanning Calorimetry (DSC and Field Emission Scanning Electronic Microscopy (FESEM. The extracted cellulose was analyzed for cellulose composition, and subsequently modified to CMSC with a degree of substitution (DS 0.6 by typical carboxymethylation reactions. X-ray diffraction analysis indicated that the crystallinity of the sago cellulose was reduced after carboxymethylation. FTIR and NMR studies indicate that the hydroxyl groups of the cellulose fibers were etherified through carboxymethylation to produce CMSC. Further characterization of the cellulose and CMSC were performed using FESEM and DSC. The purity of CMSC was analyzed according to the American Society for Testing and Materials (ASTM International standards. In this case, acid and alkaline treatments coupled with high-pressure defibrillation were found to be effective in depolymerization and defibrillation of the cellulose fibers. The synthesized CMSC also shows no toxicity in the cell line studies and could be exploited as a pharmaceutical excipient.

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

    Directory of Open Access Journals (Sweden)

    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

  3. Resin Bonding of Self-Etch Adhesives to Bovine Dentin Bleached from Pulp Chamber

    Science.gov (United States)

    Haruyama, Akiko; Kato, Junji; Takemoto, Shinji; Oda, Yutaka; Kawada, Eiji; Takahashi, Toshiyuki; Furusawa, Masahiro

    2016-01-01

    This study evaluated the microtensile bond strength (μTBS) of 1-step self-etch adhesives (1-SEAs) and 2-step self-etch adhesives (2-SEAs) to pulp chamber dentin immediately after bleaching with 2 types of common bleaching techniques. Pulp chamber dentin of bovine teeth was bleached using 30% hydrogen peroxide (H2O2) solution with quartz-tungsten-halogen light-curing unit (Group 1) and 3.5% H2O2-containing titanium dioxide (TiO2) (Pyrenees®) activated with 405-nm violet diode laser for 15 min (Group 2). Unbleached specimens were placed in distilled water for 15 min and used as controls. After treatment, dentin was bonded with resin composite using 1-SEA or 2-SEA and stored in water at 37°C for 24 h. Each specimen was sectioned and trimmed to an hourglass-shape and μTBS was measured. Fractured specimens were examined under a scanning electron microscope to determine fracture modes. All specimens in Group 1 failed before proper bonding tests. In Group 2, the μTBS of 2-SEA was significantly greater (with no failed specimens) than 1-SEA (where 21 out of 36 failed). These results indicate that 2-SEA is a better adhesive system than 1-SEA on bleached dentin. Our results also demonstrated that application of H2O2 significantly decreases bond strength of resin to dentin; however, in the case of nonvital tooth bleaching, Pyrenees® is a better alternative to the conventional 30% H2O2 bleaching. PMID:27747220

  4. 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.

  5. Rheology of lyocell solutions from different cellulosic sources and development of regenerated cellulosic microfibers

    Science.gov (United States)

    Li, Zuopan

    2003-10-01

    The primary goals of the study were to develop manufactured cellulosic fibers and microfibers from wood pulps as well as from lignocellulosic agricultural by-products and to investigate alternative cellulosic sources as raw materials for lyocell solutions. A protocol was developed for the lyocell preparation from different cellulose sources. The cellulose sources included commercial dissolving pulps, commercial bleached hardwood, unbleached hardwood, bleached softwood, unbleached softwood, bleached thermomechanical pulp, unbleached thermomechanical pulp, bleached recycled newsprint, unbleached recycled newsprint, bagasse and kudzu. The rheological behavior of solutions was characterized. Complex viscosities and effective elongational viscosities were measured and the influences of parameters such as cellulose source, concentration, bleaching, and temperature were studied. One-way ANOVA post hoc tests were carried out to identify which cellulose sources have the potential to produce lyocell solutions having similar complex viscosities to those from commercial dissolving pulps. Lyocell solutions from both bleached and unbleached softwood and hardwood were classified as one homogenous subset that had the lowest complex viscosity. Kudzu solutions had the highest complex viscosity. The results showed the potential to substitute DP 1457 dissolving pulp with unbleached recycled newsprint pulps, to substitute DP 1195 dissolving pulp with bleached and unbleached thermomechanical pulps, to substitute DP 932 dissolving pulp with bleached thermomechanical pulps or bleached recycled newsprint pulps, to substitute DP 670 dissolving pulp with bagasse. Lyocell fibers were produced from selected solutions and were treated to produce microfibers. Water, sulfuric acid solutions and sodium hydroxide solutions were used. The treatment of lyocell fibers in 17.5% NaOH solutions for five minutes at 20°C successfully broke the fibers into fibrils along fiber axis. The diameters of the

  6. Structure and properties of a pulp fibre-reinforced composite with regenerated cellulose matrix

    Science.gov (United States)

    Gindl, W.; Schöberl, T.; Keckes, J.

    2006-04-01

    Fully bio-based cellulose cellulose composites were produced by partly dissolving beech pulp fibres in lithium chloride/dimethylacetamide (LiCl/DMAc) and subsequent regeneration of matrix cellulose in the presence of undissolved fibres. Compared to cellulose epoxy composites produced from the same fibres, a two-fold increase in tensile strength and elastic modulus was observed for cellulose cellulose composites. From scanning electron microscopy and nanoindentation it is concluded that changes in the fibre cell wall during LiCl/DMAc treatment, improved matrix properties of regenerated cellulose compared to epoxy, and improved fibre matrix adhesion are responsible for the superior properties of cellulose cellulose composites.

  7. 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.

  8. STUDY ON THE BULK DENSITY OF HIGH CONSISTENCY PULP AND ENGINEERING APPLICATION IN THE BLEACHING TOWER

    Directory of Open Access Journals (Sweden)

    Ke-Fu Chen

    2011-02-01

    Full Text Available From experimental simulation of the process of high consistency pulp moving in a bleaching tower, the aerated bulk density and packed bulk density were measured and studied by using a self-made experimental system. The scattered experimental data – pressure p, and bulk density difference, which was between packed bulk density and aerated bulk density (ρ-ρ0 – were fitted by using Matlab software, and some good-fitting regression curves and equations were obtained. The results showed there was a break point W in the regression curves; within the range of pressure between zero and W the relationship between (ρ-ρ0 and p was a linear function, while for pressure between W and 70000 the relationship was a power function. To effectively meet with the bleaching response for the different kinds and different consistencies of pulp in the tower, by using the fitting regression equations combined with the expressions of average bulk density and pressure in the tower caused by gravity-driven pulp, two equations for average packed density ρa were deduced with the aim of deciding the maximum volume value of the tower, in agreement with the sizes of the towers presently used by major companies.

  9. Surface modification of cellulose materials : from wood pulps to artificial blood vessels

    OpenAIRE

    Ahrenstedt, Lage

    2007-01-01

    This thesis describes the improvement of two radically different cellulose materials, paper and artificial blood vessels, constructed from two diverse cellulose sources, wood pulp and Acetobacter xylinum. The improvement of both materials was possible due to the natural affinity of the hemicellulose xyloglucan for cellulose. Chemical and mechanical pulps were treated with xyloglucan in the wet-end prior to hand sheet formation or by spray application of dry hand sheets, loading a comparable a...

  10. Photoyellowing inhibition of bleached high yield pulps using novel water-soluble UV screens.

    Science.gov (United States)

    Argyropoulos, D S; Halevy, P; Peng, P

    2000-02-01

    To address the deficiencies of benzophenone UV screens for preventing brightness reversion in high yield mechanical papers, we synthesized a new series of such materials with enhanced water solubility and compatibility with the lignocellulosic substrate. A series of 2,4-dihydroxybenzophenones (DHB) were synthesized containing various Mannich bases at the C3 position of one of its rings. They possess the UV-screening ability of o-hydroxylbenzophenones, and they also contain tertiary nitrogen atoms that may function as radical scavengers. Aqueous solutions of the hydrochloride salt of 3-(dimethylaminomethylene)-2,4-dihydroxylbenzophenone (1), when applied on bleached chemithermomechanical pulp (CTMP) sheets, were significantly more efficient in preventing photoyellowing than the original DHB applied on the sheets from ethanol-water solutions. This confirmed our original hypothesis that increasing the compatibility of the UV screen with the lignocellulosic matrix would increase its efficiency in preventing photoyellowing. Compound 1, however, was found to be somewhat more effective than its hydrochloride salt toward preventing photoyellowing. This was attributed to the synergistic action of the free tertiary aminic center attached on the molecule with its UV-screening ability. To comprehend further the various parameters that influence the photoyellowing inhibition performance of these compounds and DHB with bleached CTMP pulp fibers, a series of handsheets were prepared at different pH. The interactions of the protonated compound 1 with pulp fibers were then evaluated by studying their kinetics of absorption and desorption to and from the fiber matrix. This part of our study found that the adsorption of protonated Mannich derivatives of DHB onto pulp is most likely governed by a cation-exchange mechanism involving the cationic amine group with the sulfonic and carboxylic acid groups located on the surface of the fibers. The pH the paper sheet was made from was also

  11. Cellulose kraft pulp reinforced polylactic acid (PLA composites: effect of fibre moisture content

    Directory of Open Access Journals (Sweden)

    Elias Retulainen

    2016-06-01

    Full Text Available PLA offers a competitive and CO2 neutral matrix to commonly used polyolefin polymer based composites. Moreover, the use of PLA reduces dependency on oil when producing composite materials. However, PLA has a tendency of hydrolytic degradation under melt processing conditions in the presence of moisture, which remains a challenge when processing PLA reinforced natural fibre composites. Natural fibres such as cellulose fibres are hygroscopic with 6–10 wt% moisture content at 50–70% relative humidity conditions. These fibres are sensitive to melt processing conditions and fibre breakage (cutting also occur during processing. The degradation of PLA, moisture absorption of natural fibres together with fibre cutting and uneven dispersion of fibres in polymer matrix, deteriorates the overall properties of the composite. In the given research paper, bleached softwood kraft pulp (BSKP reinforced PLA compounds were successfully melt processed using BSKP with relatively high moisture contents. The effect of moist BSKP on the molecular weight of PLA, fibre length and the mechanical properties of the composites were investigated. By using moist never-dried kraft pulp fibres for feeding, the fibre cutting was decreased during the melt compounding. Even though PLA degradation occurred during the melt processing, the final damage to the PLA was moderate and thus did not deteriorate the mechanical properties of the composites. However, comprehensive moisture removal is required during the compounding in order to achieve optimal overall performance of the PLA/BSKP composites. The economic benefit gained from using moist BSKP is that the expensive and time consuming drying process steps of the kraft pulp fibres prior to processing can be minimized.

  12. Pengaruh % Charge Klorin Dioksida (Clo2) Terhadap Penurunan Bilangan Kappa Dari Proses Unbleach Blending Ke Proses Bleaching D0 Stage Di PT. Toba Pulp Lestari, Tbk Porsea

    OpenAIRE

    Sagala, Winarto

    2011-01-01

    Kappa number is one of quality parameters in pulp industry. Kappa number is used to measure the degree of pulp delignification in bleaching plant. By making the variations of % charge chlorine dioxide (ClO2) in stage one of bleaching plant, it will obtained by varying kappa numbers. Kappa number analysis is done by titrimetric using oxidation – reduction methods. From the analysis, the greater the % charge chlorine dioxide (ClO¬2) in bleaching plant, kappa number will be more small.

  13. CELLULOSIC PULPS OF CEREAL STRAWS AS RAW MATERIAL FOR THE MANUFACTURE OF ECOLOGICAL PACKAGING

    Directory of Open Access Journals (Sweden)

    Fátima Vargas,

    2012-07-01

    Full Text Available The aim of this work was to study the potential application of four types of cereal straws: oats, maize, rapeseed, and barley, in order to obtain cellulose pulp through the Specel® process for use in the manufacture of 100% biodegradable and ecological packaging. Raw materials were chemically characterized to determine alcohol-extractives, ash, lignin, holocellulose, and α-cellulose. Cellulosic pulps obtained from raw materials were characterized to determine yield, Kappa number, and viscosity. Paper sheets made from cellulosic pulps were characterized to determine beating degree, tensile index, stretch, burst index, tear index, and brightness. Finally, the results were compared to the raw material used in the industrial manufacturing of packaging (wheat. The four studied raw materials (oats, maize, rapeseed, and barley were judged to be suitable for use in the Specel® process to obtain cellulosic pulp suitable for production of ecological containers.

  14. Selectivity Studies of Oxygen and Chlorine Dioxide in the Pre-Delignification Stages of a Hardwood Pulp Bleaching Plant

    OpenAIRE

    Barroca, Maria J. M. C.; Marques, Pedro J. T. S.; Seco, Isabel M.; Castro, José Almiro A. M.

    2001-01-01

    This work is concerned with the role of oxygen on the selectivity of chlorine dioxide in the pre-delignification stage of a E. globulus pulp bleaching plant. Its main purpose is to study the selectivity of chlorine dioxide when applied to an oxygen pre-delignified hardwood kraft pulp and to compare it to that of a conventional pre-delignification with chlorine dioxide (D). The intrinsic viscosity and kappa number were used to follow the polysaccharides degradation and the delignification rate...

  15. ECF BLEACHING WITH A FINAL HYDROGEN PEROXIDE STAGE: IMPACT ON THE CHEMICAL COMPOSITION OF Eucalyptus globulus KRAFT PULPS

    Directory of Open Access Journals (Sweden)

    Pedro E. G. Loureiro

    2010-11-01

    Full Text Available Two industrial elemental chlorine free (ECF bleaching sequences, D0(EOPD1(EPD2 and OQ(PODP, are compared with respect to the bulk content of lignin, carboxyl, hexeneuronic acids (HexA, and reducing groups after each bleaching stage. HexA groups contribute significantly to the total content of carboxyl groups, and their degradation during chlorine dioxide bleaching is reflected by a decrease of the carboxyl content. The higher degradation using an enhanced use of oxygen-based bleaching chemicals is associated with a higher fiber charge reduction, mainly due to xylan depletion. Additionally, the effect of process variables of a laboratory final hydrogen peroxide stage on the chemical composition of the fully bleached pulp (D0(EOPD1P and OQ(PODP is studied. The ability of final peroxide bleaching to raise the content of carboxyl groups is dependent on the operating conditions and pulp bleaching history. A balance between carbohydrate oxidation and dissolution of oxidized groups determines the effect on fiber charge. The effect of hydrogen peroxide stabilizers added into the final stage on the content of carboxyl groups is also reported.

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

    OpenAIRE

    T. R. Chaparro; E. C. Pires

    2011-01-01

    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 g...

  17. A New Freeze Concentration Process for Minimum Effluent Process in Bleached Pulp

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Ru-Ying; Botsaris, Gregory D.

    2001-03-06

    This project researches freeze concentration as a primary volume reduction technology for bleaching plant effluents from paper-pulp mills before they are treated by expensive technologies, such as incineration, for the destruction of the adsorbable organic halogens. Previous laboratory studies show that freeze concentration has a greater than 99.5% purification efficiency for volatile, semivolatile, and nonprocess elements, or any other solute, thus producing pure ice that can be reused in the mill as water. The first section evaluates the anticipated regulatory and public pressures associated with implementing the technology; the remaining sections deal with the experimental results from a scaled-up freeze concentration process in a 100-liter pilot-plant at Tufts University. The results of laboratory scale experiments confirmed that the freeze concentration technology could be an efficient volume reduction technology for the above elements and for removing adsorbable organic hologens and or nonprocess elements from recycled water. They also provide the necessary data for designing and operating a larger pilot plant, and identify the technical problems encountered in the scale-up and the way they could be addressed in the larger scale plants. This project was originally planned to include the operation of a large pilot plant in the facilities of Swenson Process Equipment Inc., and a field test at a pulp mill, but the paper company withdrew its financial support for the field test. In place of a final economic evaluation after the field test, a preliminary evaluation based on the small pilot plant data predicts an economically reasonable freeze concentration process in the case of reduction of the bleaching-effluent flow to less than 5 m3/kkg pulp, a target anticipated in the near future.

  18. Ecotoxicological assessment of a recipient lake sediment of bleached-kraft pulping discharges

    Energy Technology Data Exchange (ETDEWEB)

    Suominen, K.P.; Wittmann, C.; Liukkonen, M.; Kaehkoenen, M.A.; Salkinoja-Salonen, M.S.

    1999-10-01

    The authors assessed the biological status of age-dated sediments in Lake Saimaa, a recipient lake for wastewaters from pulp and paper industry for more than 100 years that has also received kraft pulp bleaching wastewater since 1954. Adenosine triphosphate content dropped in the recipient sediment from the top 1 cm to 4 to 6 cm below the sediment surface by a factor of 1,000 but increased again in deeper, older layers. The dominant species in the diatom community, Aulacoseira alpigena and Cyclotella kuetzingiana, disappeared and were replaced by Asterionella formosa in the 4- to 6-cm layer. This layer was three- to fivefold more toxic to Vibrio fischeri (as measured by the median effective concentration) and slightly genotoxic (as measured by the SOS-chromotest induction ratio, I{sub c}/I{sub o} for Esherichia coli PQ37) compared with the layers above and below it. The 4- to 6-cm layer also contained up to 4,900 mg of solvent-soluble organic halogen. Enzyme activity was detected at depths of 0 to 1 cm and 4 to 6 cm, and more than 90% of the enzymes were bound to the particulate matter. Ninety-seven percent of the organic halogen in the sediment was particle bound. Apparently, full ecological recovery occurred in the layer from 0 to 1 cm, which had accumulated in 1990s, after the discharging pulp mill discontinued use of Cl{sub 2} in the bleaching process and installed full-scale biological treatment for the wastewaters.

  19. Composition, texture and methane potential of cellulosic residues from Lewis acids organosolv pulping of wheat straw.

    Science.gov (United States)

    Constant, Sandra; Barakat, Abdellatif; Robitzer, Mike; Di Renzo, Francesco; Dumas, Claire; Quignard, Françoise

    2016-09-01

    Cellulosic pulps have been successfully isolated from wheat straw through a Lewis acids organosolv treatment. The use of Lewis acids with different hardness produced pulps with different delignification degrees. The cellulosic residue was characterised by chemical composition, X-ray diffraction, FT-IR spectroscopy, N2 physisorption, scanning electron microscopy and potential for anaerobic digestibility. Surface area and pore volume increased with the hardness of the Lewis acid, in correspondence with the decrease of the amount of lignin and hemicellulose in the pulp. The non linearity of the correlation between porosity and composition suggests that an agglomeration of cellulose fibrils occurs in the early stages of pulping. All organosolv pulps presented a significantly higher methane potential than the parent straw. A methane evolution of 295Ncm(3)/g OM was reached by a moderate improvement of the accessibility of the native straw. PMID:27295251

  20. Electron-beam stimulation of the reactivity of cellulose pulps for production of derivatives

    Science.gov (United States)

    Iller, Edward; Kukiełka, Aleksandra; Stupińska, Halina; Mikołajczyk, Włodzimierz

    2002-03-01

    New alternative technologies for manufacture of cellulose fibers are currently under development. The effect of electron beam irradiation on various types of cellulose pulps have been studied in order to improve the reactivity of raw material for production of cellulose derivatives. Three different types of textile pulps, Alicell (Canada), Borregaard (Norwegian), Ketchikan (USA) and Kraft softwood as well as Kraft hardwood pulps, have been irradiated with 10 MeV electron beam from LAE 13/g linear accelerator with dose 10, 15, 20, 25 and 50 kGy. Electron paramagnetic resonance spectroscopy (ESR) and gel permeation chromatography (GPC) were applied for determination of structural changes in irradiated pulps. Such parameters as viscosity, average degree of polymerization and α-cellulose contents were determinated by means of analytical methods. Results of there investigations are presented and discussed.

  1. Progressive structural changes of Avicel, bleached softwood, and bacterial cellulose during enzymatic hydrolysis

    OpenAIRE

    Kabindra Kafle; Heenae Shin; Lee, Christopher M; Sunkyu Park; Kim, Seong H.

    2015-01-01

    A comprehensive picture of structural changes of cellulosic biomass during enzymatic hydrolysis is essential for a better understanding of enzymatic actions and development of more efficient enzymes. In this study, a suite of analytical techniques including sum frequency generation (SFG) spectroscopy, infrared (IR) spectroscopy, x-ray diffraction (XRD), and x-ray photoelectron spectroscopy (XPS) were employed for lignin-free model biomass samples—Avicel, bleached softwood, and bacterial cellu...

  2. Treatment of Pulp Mill D-Stage Bleaching Effluent Using a Pilot-Scale Electrocoagulation System.

    Science.gov (United States)

    Perng, Yuan-Shing; Wang, Eugene I-Chen

    2016-03-01

    A pilot-scale study was conducted using electrocoagulation technology to treat chlorine dioxide bleaching-stage effluent of a local pulp mill, with the purpose of evaluating the treatment performance. The operating variables were the current density (0 ~ 133.3 A/m(2)) and hydraulic retention time (HRT, 6.5 ~ 16.25 minutes). Water quality indicators investigated were the conductivity, suspended solids (SS), chemical oxygen demand (COD), true color, and hardness. The results showed that electrocoagulation technology can be used to treat D-stage bleaching effluent for water reuse. Under the operating conditions studied, the removal of conductivity and COD always increased with increases in either the current density or HRT. The highest removals obtained at 133.3 A/m(2) and an HRT of 16.25 minutes for conductivity, SS, COD, true color, and hardness were respectively 44.2, 98.5, 75.0, 85.9, and 36.9% with aluminum electrodes. Iron electrodes were not applicable to the D-stage effluent due to formation of dark-colored ferric complexes.

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

    Directory of Open Access Journals (Sweden)

    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.

  4. Progressive structural changes of Avicel, bleached softwood, and bacterial cellulose during enzymatic hydrolysis

    Science.gov (United States)

    Kafle, Kabindra; Shin, Heenae; Lee, Christopher M.; Park, Sunkyu; Kim, Seong H.

    2015-10-01

    A comprehensive picture of structural changes of cellulosic biomass during enzymatic hydrolysis is essential for a better understanding of enzymatic actions and development of more efficient enzymes. In this study, a suite of analytical techniques including sum frequency generation (SFG) spectroscopy, infrared (IR) spectroscopy, x-ray diffraction (XRD), and x-ray photoelectron spectroscopy (XPS) were employed for lignin-free model biomass samples—Avicel, bleached softwood, and bacterial cellulose—to find correlations between the decrease in hydrolysis rate over time and the structural or chemical changes of biomass during the hydrolysis reaction. The results showed that the decrease in hydrolysis rate over time appears to correlate with the irreversible deposition of non-cellulosic species (either reaction side products or denatured enzymes, or both) on the cellulosic substrate surface. The crystallinity, degree of polymerization, and meso-scale packing of cellulose do not seem to positively correlate with the decrease in hydrolysis rate observed for all three substrates tested in this study. It was also found that the cellulose Iα component of the bacterial cellulose is preferentially hydrolyzed by the enzyme than the cellulose Iβ component.

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

    Directory of Open Access Journals (Sweden)

    M. A. Quaiyyum

    2008-08-01

    Full Text Available 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. The soda-EDA process produced better pulp yield, kappa number, viscosity, and α-cellulose content as compared to the kraft process. Increasing EDA charge in the soda liquor increased pulping selectivity and α-cellulose content. Degraded cellulose (R18-R10 in soda-EDA pulp was lower than kraft pulp. But the bleachability of soda-EDA pulp was inferior as compared to kraft pulp in DED bleaching.

  6. Eucalyptus kraft pulp production: Thermogravimetry monitoring

    International Nuclear Information System (INIS)

    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.

  7. Genotoxicity and toxicity evaluations of ECF cellulose bleaching effluents using the Allium cepa L. test.

    Science.gov (United States)

    Roa, O; Yeber, M C; Venegas, W

    2012-08-01

    Toxicity and genotoxicity tests were performed on root cells of Allium cepa in order to evaluate wastewater quality following an ECF cellulose bleaching process. The results revealed a toxic effect of the effluent, with inhibition of meristem growth and generally lower values of metaphase, anaphase and telophase indices at pH 10.5 than pH 7 for all effluent concentrations. The genotoxicity effect was different from the toxic effect given that the micronucleus and the chromosomal aberration tests in anaphase-telophase cells were low over all ranges of the studied effluent concentrations. PMID:22990817

  8. KINETICS OF DELIGNIFICATION AND CARBOHYDRATE DEGRADATION DURING OXYGEN BLEACHING

    Institute of Scientific and Technical Information of China (English)

    K.LNguyen

    2004-01-01

    Carbohydrate degradation during oxygen bleaching isassociated with cleavage reactions. It is apparent thatthe loss of the cellulose DPis strongly affected by(degree ofpolymisation) the extent of thedelignification. A strong linear correlation can beestablished between the DP of cellulose chains andthe residual lignin in the pulp. The Nuclear Growthconcept and Percolation Theory for heterogenoussystem can be combined to formulate kinetic modelsfor both the delignification and the degradation ofcarbohydrate. The models prediction is statisticallyrobust and can be applied to different pulps atdifferent bleachin~ conditions.

  9. KINETICS OF DELIGNIFICATION AND CARBOHYDRATE DEGRADATION DURING OXYGEN BLEACHING

    Institute of Scientific and Technical Information of China (English)

    K. L Nguyen

    2004-01-01

    Carbohydrate degradation during oxygen bleaching is associated with cleavage reactions. It is apparent that the loss of the cellulose DP (degree ofpolymisation)is strongly affected by the extent of the delignification. A strong linear correlation can be established between the DP of cellulose chains and the residual lignin in the pulp. The Nuclear Growth concept and Percolation Theory for heterogenous system can be combined to formulate kinetic models for both the delignification and the degradation of carbohydrate. The models prediction is statistically robust and can be applied to different pulps at different bleaching conditions.

  10. SUBSTITUTION OF HIGH-YIELD-PULP FOR HARDWOOD BLEACHED KRAFT PULP IN PAPER PRODUCTION AND ITS EFFECT ON ALKENYL SUCCINIC ANHYDRIDE SIZING

    Directory of Open Access Journals (Sweden)

    Qijie Chen,

    2012-02-01

    Full Text Available In recent years there has been an increasing interest in using high-yield pulp (HYP as a partial replacement for hardwood bleached kraft pulp (HWBKP in the production of high-quality fine papers as a cost-effective way of improving the product performance. This study investigated the substitution of HYP for HWBKP and its effect on the Alkenyl Succinic Anhydride (ASA sizing performance. The results showed that the substitution of an aspen HYP for HWBKP can increase the ASA sizing performance at a HYP substitution as high as 15 to 20%. The ASA addition sequence has an influence on the ASA sizing performance and first adding ASA to the HYP followed by mixing with kraft pulps was the preferred method. Using precipitated calcium carbonate (PCC as a paper filler at a dosage of less than 20% can increase the ASA sizing performance due to the contribution of the calcium soap of the hydrolysed ASA. A PCC dosage greater than 20% resulted in a negative impact on the sizing performance. It was also found that different PCC loading sequences can also affect the ASA sizing performance.

  11. High biodegradation levels of 4,5,6-trichloroguaiacol by Bacillus sp. isolated from cellulose pulp mill effluent

    OpenAIRE

    Tondo E.C.; Andretta C.W.S.; Souza C.F.V.; Monteiro A.L.; Henriques J.A.P.; Ayub M.A.Z.

    1998-01-01

    An aerobic Gram positive spore-forming bacterium was isolated from cellulose pulp mill effluent. This microorganism, identified as Bacillus sp. and named IS13, was able to rapidly degrade the organic chlorinated compound 4,5,6-trichloroguaiacol (4,5,6-TCG) from a culture containing 50 mg/l, which corresponds to about 3x104 times the concentration found in the original effluent. The biodegradation of this compound, usually found in cellulose pulp mill effluents, was evaluated by spectrophotome...

  12. 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

    Energy Technology Data Exchange (ETDEWEB)

    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)

  13. 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.

  14. THE EFFECT OF DIFFERENT STABILIZERS ON ALKALINE H2O2 BLEACHING OF NS REED PULP

    Institute of Scientific and Technical Information of China (English)

    MeihongNiu; ShulanShi; YunzhanZhang

    2004-01-01

    This paper uses a new stabilizer of H2O2 bleaching and compares the stabilizing effect of the new stabilizer with that of Na2SiO3. The results show that the new stabilizer is better than the conventional Na2SiO3. The optimum conditions of the stable latterprocess bleaching of H2O2 as follow: NaOH 3%,MgSO4 0.05%, H2O2 3%, stabilizer 3%, temperature80℃, concentration 12%, time 3h.

  15. THE EFFECT OF DIFFERENT STABILIZERS ON ALKALINE H2O2 BLEACHING OF NS REED PULP

    Institute of Scientific and Technical Information of China (English)

    Meihong Niu; Shulan Shi; Yunzhan Zhang

    2004-01-01

    This paper uses a new stabilizer of H2O2 bleaching and compares the stabilizing effect of the new stabilizer with that of Na2SiO3. The results show that the new stabilizer is better than the conventional Na2SiO3. The optimum conditions of the stable latter process bleaching of H2O2 as follow: NaOH 3%,MgSO4 0.05%, H2O2 3%, stabilizer 3%, temperature 80℃, concentration 12%, time 3h.

  16. Purified cellulose, soybean hulls and citrus pulp as a source of fiber for weaned piglets

    Directory of Open Access Journals (Sweden)

    Leonardo Augusto Fonseca Pascoal

    2015-10-01

    Full Text Available Dietary fiber is an important component, which has a direct effect on intake, digestion, and absorption of nutrients; and also alters intestinal microbiota and morphology according to solubility. One digestibility trial and one performance experiment were performed to evaluate the effects of sources of fiber in diets for 21 day weaned piglets. The experimental diets used in both trials consisted of a control diet and diets with purified cellulose, soybean hulls or citrus pulp as a main source of dietary fiber. To evaluate the digestibility of nutrients (Assay 1, the total feces and urine collection method was used. The fiber sources did not affect nutrient digestibility, except for soluble fiber, which increased with the inclusion of citrus (Citrus sinensisL. pulp. To evaluate performance, morphophysiology and microbiology of the digestive tract of weaned piglets, a total of 32 castrated male piglets was used. Slaughter of animals was implemented at 35 and 50 days of age. The use of soybean (Glycine max L. hulls and citrus pulp in diets increased the number of goblet cells and the density of villi in the jejunum. The viscosities of stomach and cecum contents increased due to the addition of citrus pulp. Soybean hulls and the citrus pulp included in diets reduced the occurrence of E. coli in the small intestines of piglets slaughtered at 35 days of age. Among the fiber sources, purified cellulose in piglet diets promotes better performance of animals, due to the modulation of the small intestine microbiota, with lower E. coli occurrence resulting in higher villus density.

  17. THE PEROXYMONOCARBONATE ANIONS AS PULP BLEACHING AGENTS. PART 1. RESULTS WITH LIGNIN MODEL COMPOUNDS AND CHEMICAL PULPS

    Directory of Open Access Journals (Sweden)

    Francis K Attiogbe

    2010-08-01

    Full Text Available The peroxymonocarbonate mono-anion (HCO4─ is generated when the bicarbonate anion is added to a H2O2 solution. The mono-anion is believed to have a pKa value of ca. 10 and as such would start dissociating to the di-anion (CO42─ at pH ca. 8. The mono-anion should demonstrate electrophilic properties, while the di-anion should be a nucleophile. In an alkaline, non-sulfur pulping process such as soda/AQ, Na2CO3 could be obtained from the chemical recovery system and carbonated with CO2 from a flue gas stream to produce NaHCO3. In such a case only H2O2 would need to be purchased to generate the peroxymonocarbonate (PMC anions. Bicarbonate anions could also be produced from the carbonation of solutions containing NaOH, Mg(OH2 or mined Na2CO3. One or both of the PMC anions was found to be effective in oxidizing two lignin model compounds as well as lowering the lignin content of kraft and soda/AQ hardwood pulps. The PMC anions were generated in-situ by NaHCO3 or Na2CO3 + CO2 addition to dilute H2O2 solutions.

  18. Evaluation of the use of powdered activated carbon in membrane bioreactor for the treatment of bleach pulp mill effluent.

    Science.gov (United States)

    Amaral, Míriam C S; Lange, Liséte C; Borges, Cristiano P

    2014-09-01

    In this paper, the use of powered activated carbon (PAC) in membrane bioreactor (MBR) employed in the treatment of bleach pulp mill effluents was evaluated. The MBR was operated with hydraulic residence time of 9.5 h and PAC concentration of 10 g/L. The addition of PAC to the MBR reduced the average concentration of chemical oxygen demand (COD) in the permeate from 215 mg/L (82% removal efficiency) to 135 mg/L (88% removal efficiency), producing an effluent that can be reused on bleaching stage. Moreover, the addition of PAC to the MBR resulted in the reduction in applied pressure and provided a more stable operation during the monitoring period. This occurrence was probably due to the increase of critical flux after the addition of PAC. The fouling mechanism was investigated and the results showed that controlling the concentration of soluble microbial products (SMP) and extracellular polymeric substance (EPS) by using PAC and keeping the operational flux below critical flux is of major importance for MBR operational sustainability. PMID:25327019

  19. Low environmental impact bleaching sequences for attaining high brightness level with eucalyptus SPP pulp

    Directory of Open Access Journals (Sweden)

    M. M. Costa

    2009-03-01

    Full Text Available The alternatives used for minimizing the usage of chlorine dioxide in bleaching sequences included a hot acid hydrolysis (Ahot stage, the use of hot chlorine dioxide (Dhot and ozone stages at medium consistency and high consistency (Zmc and Zhc, in addition to stages with atmospheric hydrogen peroxide (P and pressurized hydrogen peroxide (PO. The results were interpreted based on the cost of the chemical products, bleaching process yields and on minimizing the environmental impact of the bleaching process. In spite of some process restrictions, high ISO brightness levels were kept around 90 % brightness. Additionally, the inclusion of stages like acid hydrolysis, pressurized peroxide and ozone in the bleaching sequences provided an increase in operating flexibility, aimed at reducing environmental impact (ECF Light. The Dhot(EOPD(PO sequence presented lower operating cost for ISO brightness above 92 %. However, this kind of sequence was not allowed for closing the wastewater circuit, even partially. For ISO brightness level around 91%, the AhotZhcDP sequence presented a lower operating cost than the others.

  20. 二氧化氯漂白技术用于提高竹浆粕白度的研究%Improving Brightness of Bamboo Dissolving Pulp by Chlroine Dioxide Bleaching

    Institute of Scientific and Technical Information of China (English)

    陈秋艳; 曹石林; 马晓娟; 陈礼辉; 黄六莲

    2014-01-01

    The importance and necessarity of chlorine dioxide bleaching during production of bamboo dissolving pulp were discussed in present study. Effects of ClO2 dosage, NaOH dosage, bleaching temperature and time in D1 stage, and ClO2 dosage in D2 stage on pulp properties, including α-cellulose content, pentosan content, brightness, Kappa number, pulp viscosity and ash content, were examined respectively. The relationships between pulp brightness and α-cellulose, pentosan, ash contents in D1 stage were established. The results showed that the optimal bleaching for preparing bamboo dissolving pulp with chlorine dioxide(D1) were conducted as the pulp was treated by 1. 52% of ClO2 and 0. 76% of NaOH at 75℃ for 120 minutes. The pulp brightness was increased by 78. 8%, and only a 19. 55% of pulp viscosity was observed after D1 stage. The ClO2 dosage in D2 stage was 0. 8%. And the other conditions were as follows:0. 4% NaOH, 75℃ and 120 min, 10% of pulp quality mark. Theα-cellulose content increased with the rise of pulp brightness, meanwhile, accompanying with the decline of pentosan and ash content. This is positive for the quality modification of the obtained bamboo dissolving pulp. After the bleaching by two stages of chlorine dioxide, the brightness of the final bamboo dissolving pulp reached up to 88. 2% (ISO).%探讨了竹浆粕生产过程中二氧化氯漂白( D1、D2段)的重要性和必要性,D1段和D2段分别研究了ClO2用量、NaOH用量、温度、时间4个因素及ClO2用量单因素对二氧化氯漂白效果的影响,包括α-纤维素、聚戊糖、白度、卡伯值、黏度、灰分等性能,其中D1段分析了白度提高与浆粕α-纤维素、聚戊糖及灰分的关系。结果表明,D1段最优工艺条件为:ClO2用量1.52%且NaOH用量0.76%( NaOH与ClO2质量比1:2),温度75℃,时间120 min,浆质量分数10%。经D1段处理后,竹浆白度提高率达到了78.8%,黏度下降率仅为19.55%,漂白选择性高。在D1段漂

  1. Effect of Adding Acid-Base Buffer During Wheat Straw Pulp DEP Bleaching on the Pulp Properties%麦草浆DEP漂白中添加酸碱缓冲剂对纸浆性能的影响

    Institute of Scientific and Technical Information of China (English)

    李清林; 韩卿; 王伦; 侯广强

    2011-01-01

    采用DEP短序工艺漂白麦草浆,分别研究了在D段和P段加入酸碱缓冲剂控制浆料体系的pH值,使漂液充分发挥作用,在不影响漂白效果的前提下,达到减少漂液用量的目的。SEM观察表明,纸浆在D段/P段漂白时添加酸碱缓冲剂,纤维受损程度减弱。%DEP short sequence was used to bleach wheat straw pulp, the acid-base buffers were added in chorine dioxide and peroxide bleaching stages respectively in order to control the pH in the slurry system. Through this, the bleaching results improved and the chemical dosage reduced. SEM observation of the sheet made with wheat straw pulp revealed that the level of fiber damage was reduced in the process of ClO2E bleaching and H2O2 bleaching by adding the acid-base buffer.

  2. Quantification of the efficiency for photo-bleached pigments using cellulose matrixes as substrate and digitalized gray scale

    Science.gov (United States)

    Florez, F. L. E.; Correia Lins, E. C. C.; Lizarelli, R. F. Z.; Bagnato, V. S.

    2006-02-01

    The bleaching process is been objective of many studies since the beginning of the XX century. Heat has been used to activate the hydrogen peroxide; the aesthetic results were satisfactory, but associated with this process high incidence of hypersensitivity as well as radical endodontic treatment was observed making this technique clinically hard to implemented. Nowadays the dental bleaching is one of the most wanted aesthetic procedures by the population at the dental office. With the utilization of new light sources as LASER and LED a technique to evaluate the efficiency of photo-bleaching of many pigments is necessary. This work demonstrates a new method to quantify the breakage of pigments on a cellulose matrix using a blue LED system with 1W/cm2. We employed a computational analysis and digital spectroscopy. These matrixes were used because of its inert physical-chemical properties. The obtained results are within the expectative, where the groups irradiated with light presents more broken pigments that the group with no light, it was also possible to observe on this experiment that light acts decreasing the free energy of the reaction and that way speeding up the rate of bleaching.

  3. Responses of white sucker (Catostomus commersoni) to 20 years of process and waste treatment changes at a bleached kraft pulp mill, and to mill shutdown.

    Science.gov (United States)

    Bowron, L K; Munkittrick, K R; McMaster, M E; Tetreault, G; Hewitt, L M

    2009-11-01

    The impacts of pulp mill effluents on white sucker (Catostomus commersoni) have been studied at Jackfish Bay, ON, Canada since the late 1980s. The site receives effluent from a large bleached kraft pulp mill which is the only source of chemical contamination in the area. Many laboratory studies have looked at the toxicological consequences of pulping process changes, but the benefit of these changes have not been looked at in wild fish. Jackfish Bay white sucker showed impacts on sexual maturity, gonad size, secondary sexual characteristics and circulating steroids hormone levels in the early years of the studies, and impacts were evaluated after installation of secondary treatment (1989), major pulping process changes (1995) and after the mill ceased pulp production and effluent release (2006). The addition of secondary treatment resulted in minor improvements in wild fish health, and the conversion to elemental chlorine free (ECF) bleaching at the mill was associated with more recovery in liver and gonad size. While some impacts persist at the exposure site, reproductive parameters showed further improvement during the mill shutdown period demonstrating that biologically active chemicals are still being discharged from modernized mills. PMID:19783055

  4. Assessment of status of white sucker (Catostomus commersoni) populations exposed to bleached kraft pulp mill effluent.

    Science.gov (United States)

    Miller, David H; Tietge, Joseph E; McMaster, Mark E; Munkittrick, Kelly R; Xia, Xiangsheng; Ankley, Gerald T

    2013-07-01

    Credible ecological risk assessments often need to include analysis of population-level impacts. In the present study, a predictive model was developed to investigate population dynamics for white sucker (Catostomus commersoni) exposed to pulp mill effluent at a well-studied site in Jackfish Bay, Lake Superior, Canada. The model uniquely combines a Leslie population projection matrix and the logistic equation to translate changes in the fecundity and the age structure of a breeding population of white sucker exposed to pulp mill effluent to alterations in population growth rate. Application of this density-dependent population projection model requires construction of a life table for the organism of interest, a measure of carrying capacity, and an estimation of the effect of stressors on vital rates. A white sucker population existing at carrying capacity and subsequently exposed to pulp mill effluent equivalent to a documented exposure experienced during the period 1988 to 1994 in Jackfish Bay would be expected to exhibit a 34% to 51% annual decrease in recruitment during the first 5 yr of exposure and approach a population size of 71% of carrying capacity. The Jackfish Bay study site contains monitoring data for biochemical endpoints in white sucker, including circulating sex steroid concentrations, that could be combined with population modeling to utilize the model demonstrated at the Jackfish Bay study site for investigation of other white sucker populations at sites that are less data-rich. PMID:23504660

  5. 漂白硫酸盐苇浆制浆废水的处理%Treatment of the Waste Water from a Mill Producing Bleached Kraft Reed Pulp

    Institute of Scientific and Technical Information of China (English)

    马乐凡; 李晓林; 王跃泉

    2001-01-01

    Laboratory results of the treatment of pulping black liquor,washing and bleaching waste wate of a mill producing bleached kraft reed pulp were presented. Process and installation of reed BKP pulping waste water treatment were designed, operation parameters and running results of treatment stages were discussed. Black liquor after anaerobic treatment and acid precipitating of lignin could be mixed with washing and bleaching waste water based on the discharged ratio of the mill to discharge, the pollution load of the mixed effluent will meet the national regulation requirement after further treatment by active sludge.%讨论了漂白硫酸盐苇浆厂制浆黑液和中段废水的实验室处理结果。设计了芦苇BKP制浆废水的处理工艺流程和装置,并重点讨论了各处理段的运行参数和运行结果。BKP苇浆蒸煮黑液首先经厌氧和酸析木素处理,然后再与制浆中段水按工厂排放比例混合,混合废水经活性污泥法处理后,可达到国家标准排放。

  6. 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.

  7. 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.

  8. 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 methan

  9. A Study on Enhancement of Filtration Process with Filter Aids Diatomaceous Earth and Wood Pulp Cellulose

    Institute of Scientific and Technical Information of China (English)

    都丽红; 陈旭; 李文苹; 朱企新

    2011-01-01

    In this paper, a study to enhance the filtration for solid/liquid materials difficult to be filtered, such as highly viscous, highly compactible or gel like materials, is presented. Filter aids diatomaceous earth and wood pulp cellulose are used to enhance the filtration by improving filter cake structure and properties in the filtration of a biological health product and a highly viscous chemical fiber polymer melt product. The property of solid/liquidsystems, filtration at different flow rates, specitic cake resistance, cake wetness, filtration rate, filtrate turbidity for filter aid selection and evaluation, and operation optimization are investigated. The results are successfully applied to industrial process, .and can be used as a reference for similar filtration applications.

  10. Biodegradation of novel amino acid derivatives suitable for complexing agents in pulp bleaching applications.

    Science.gov (United States)

    Metsärinne, Sirpa; Ronkainen, Erja; Tuhkanen, Tuula; Aksela, Reijo; Sillanpää, Mika

    2007-05-01

    The biodegradability of four novel diethanolamine derivative complexing agents was examined by using two biodegradation tests standardised by OECD (301B and 301F). Ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) were employed as reference substances. Biodegradation of the new complexing agents was studied both with unacclimated and acclimated inocula as well as by simulating wastewater treatment in sequencing batch reactors (SBRs). These new complexing agents were of technical grade, and therefore, the results are only indicative but these new compounds hold promise for use as complexing agents in the pulp and paper industry. The novel complexing agents were not readily biodegradable but they showed slight biodegradation. Around 10-30% degradation was found in the SBR where degradation was followed by measurement of concentration. Moreover the novel complexing agents did not have any negative impact on reactor performance as measured by chemical oxygen demand reduction. In the standardised biodegradation tests at best around 50% degradation was observed with the acclimated inoculum and in the prolonged test whereas EDTA and DTPA exhibited no biodegradation. The elevated degradation in acclimated sludge indicates that the water treatment plant microbes are capable of decomposing these molecules under favourable conditions. The total concentration of novel complexing agents decreased slightly during biodegradation tests, while the EDTA and DTPA concentrations remained stable. PMID:17346781

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

    DEFF Research Database (Denmark)

    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...

  12. Cationic cellulose nanofibers from waste pulp residues and their nitrate, fluoride, sulphate and phosphate adsorption properties.

    Science.gov (United States)

    Sehaqui, Houssine; Mautner, Andreas; Perez de Larraya, Uxua; Pfenninger, Numa; Tingaut, Philippe; Zimmermann, Tanja

    2016-01-01

    Cationic cellulose nanofibers (CNF) having 3 different contents of positively charged quaternary ammonium groups have been prepared from waste pulp residues according to a water-based modification method involving first the etherification of the pulp with glycidyltrimethylammonium chloride followed by mechanical disintegration. The cationic nanofibers obtained were observed by scanning electron microscopy and the extent of the reaction was evaluated by conductometric titration, ζ-potential measurements, and thermogravimetric analyses. The cationic CNF had a maximum cationic charge content of 1.2mmolg(-1) and positive ζ-potential at various pH values. Sorption of negatively charged contaminants (fluoride, nitrate, phosphate and sulphate ions) and their selectivity onto cationic CNF have been evaluated. Maximum sorption of ∼0.6mmolg(-1) of these ions by CNF was achieved and selectivity adsorption studies showed that cationic CNF are more selective toward multivalent ions (PO4(3-) and SO4(2-)) than monovalent ions (F(-) and NO3(-)). In addition, we demonstrated that cationic CNF can be manufactured into permeable membranes capable of dynamic nitrate adsorption by utilizing a simple paper-making process.

  13. Cationic cellulose nanofibers from waste pulp residues and their nitrate, fluoride, sulphate and phosphate adsorption properties.

    Science.gov (United States)

    Sehaqui, Houssine; Mautner, Andreas; Perez de Larraya, Uxua; Pfenninger, Numa; Tingaut, Philippe; Zimmermann, Tanja

    2016-01-01

    Cationic cellulose nanofibers (CNF) having 3 different contents of positively charged quaternary ammonium groups have been prepared from waste pulp residues according to a water-based modification method involving first the etherification of the pulp with glycidyltrimethylammonium chloride followed by mechanical disintegration. The cationic nanofibers obtained were observed by scanning electron microscopy and the extent of the reaction was evaluated by conductometric titration, ζ-potential measurements, and thermogravimetric analyses. The cationic CNF had a maximum cationic charge content of 1.2mmolg(-1) and positive ζ-potential at various pH values. Sorption of negatively charged contaminants (fluoride, nitrate, phosphate and sulphate ions) and their selectivity onto cationic CNF have been evaluated. Maximum sorption of ∼0.6mmolg(-1) of these ions by CNF was achieved and selectivity adsorption studies showed that cationic CNF are more selective toward multivalent ions (PO4(3-) and SO4(2-)) than monovalent ions (F(-) and NO3(-)). In addition, we demonstrated that cationic CNF can be manufactured into permeable membranes capable of dynamic nitrate adsorption by utilizing a simple paper-making process. PMID:26453885

  14. EXAMINATION OF POLYCHLORINATED DIBENZO-P-DIOXINS AND POLYCHLORINATED DIBENZOFURANS INTO PROCESS WATER OF KRAFT PULP BLEACHING MILL FROM ASPECT OF ENVIRONMENTAL WATER QUALITY

    Institute of Scientific and Technical Information of China (English)

    HiroshiOhi; TomoyaYokoyama; KeiichiNakamata

    2004-01-01

    Process water of a pulp mill with kraft cooking, oxygen delignification and chlorine bleaching or chlorine dioxide (ECF) bleaching was examined from an aspect of a new level for environmental water quality in Japan. According to the new level, a concentration of dioxins consisting of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (PCBs) in environmental water is restricted to less than 1 pg- TEQ/L. We clarified that the 2,3,7,8-tetrachlorodibenzofuran (TCDF) concentrations were 0.5 pg/L or less. In addition, a main source of 1,3,6,8- and 1,3,7,9-tetrachlorodibenzo-p-dioxins in the process water seemed to be an agrochemical in water supplied from a river.

  15. EXAMINATION OF POLYCHLORINATED DIBENZO-P-DIOXINS AND POLYCHLORINATED DIBENZOFURANS INTO PROCESS WATER OF KRAFT PULP BLEACHING MILL FROM ASPECT OF ENVIRONMENTAL WATER QUALITY

    Institute of Scientific and Technical Information of China (English)

    Hiroshi Ohi; Tomoya Yokoyama; Keiichi Nakamata

    2004-01-01

    Process water of a pulp mill with kraft cooking,oxygen delignification and chlorine bleaching or chlorine dioxide (ECF) bleaching was examined from an aspect of a new level for environmental water quality in Japan. According to the new level, a concentration of dioxins consisting of polychlorinated dibenzo-p-dioxins (PCDDs),polychlorinated dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (PCBs) in environmental water is restricted to less than 1 pg- TEQ/L. We clarified that the 2,3,7,8-tetrachlorodibenzofuran (TCDF) concentrations were 0.5 pg/L or less. In addition, a main source of 1,3,6,8- and 1,3,7,9-tetrachlorodibenzo-p-dioxins in the process water seemed to be an agrochemical in water supplied from a river.

  16. ECF bleaching with a final hydrogen peroxide stage: Impact of the chemical composition of Eucalyptus globulus kraft pulps

    OpenAIRE

    Loureiro, Pedro E. G.; Eva F. Domingues; Evtuguin, Dmitry V.; M. Graça Videira Sousa Carvalho

    2010-01-01

    Two industrial elemental chlorine free (ECF) bleaching sequences, D0(EOP)D1(EP)D2 and OQ(PO)DP, are compared with respect to the bulk content of lignin, carboxyl, hexeneuronic acids (HexA), and reducing groups after each bleaching stage. HexA groups contribute significantly to the total content of carboxyl groups, and their degradation during chlorine dioxide bleaching is reflected by a decrease of the carboxyl content. The higher degradation using an enhanced use of oxygen-based bleaching ch...

  17. Exposure to bleached kraft pulp mill effluent disrupts the pituitary-gonadal axis of white sucker at multiple sites

    Energy Technology Data Exchange (ETDEWEB)

    Van Der Kraak, G.J.; Munkittrick, K.R.; McMaster, M.E.; Portt, C.B.; Chang, J.P. (Department of Zoology, University of Guelph, Ontario (Canada))

    1992-08-01

    Recent studies have demonstrated reproductive problems in white sucker (Catostomus commersoni) exposed to bleached kraft pulp mill effluent (BKME) at Jackfish Bay on Lake Superior. These fish exhibit delayed sexual maturity, reduced gonadal size, reduced secondary sexual characteristics, and circulating steroid levels depressed relative to those of reference populations. The present studies were designed to evaluate sites in the pituitary-gonadal axis of prespawning white sucker affected by BKME exposure. At the time of entry to the spawning stream, plasma levels of immunoreactive gonadotropin (GtH)-II (LH-type GtH) in male and female white sucker were 30- and 50-fold lower, respectively, than the levels in fish from a reference site. A single intraperitoneal injection of D-Arg6, Pro9N-Et sGnRH (sGnRH-A, 0.1 mg/kg) increased plasma GtH levels in male and female fish at both sites, although the magnitude of the response was greatly reduced in BKME-exposed fish. Fish at the BKME site did not ovulate in response to sGnRH-A, while 10 of 10 fish from the reference site ovulated within 6 hr. Plasma 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17,20 beta-P) levels were depressed in BKME-exposed fish and unlike fish at the reference site, failed to increase in response to sGnRH-A. Testosterone levels in both sexes and 11-ketostestosterone levels in males were elevated in fish from the reference site but were not further increased by GnRH treatment. In contrast, BKME-exposed fish exhibit a transitory increase in testosterone levels in response to the GnRH analog. In vitro incubations of ovarian follicles obtained from fish at the BKME site revealed depressed basal secretion of testosterone and 17,20 beta-P and reduced responsiveness to the GtH analog human chorionic gonadotropin and to forskolin, a direct activator of adenylate cyclase.

  18. The effect of acid hydrolysis pretreatment on crystallinity and solubility of kenaf cellulose membrane

    Energy Technology Data Exchange (ETDEWEB)

    Saidi, Anis Syuhada Mohd; Zakaria, Sarani; Chia, Chin Hua; Jaafar, Sharifah Nabihah Syed; Padzil, Farah Nadia Mohammad [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia)

    2015-09-25

    Cellulose was extracted from kenaf core pulp (KCP) by series of bleaching steps in the sequence (DEED) where D and E are referred as acid and alkali treatment. The bleached kenaf pulp (BKCP) is then pretreated with acid hydrolysis at room temperature for 1 and 3 h respectively. The pretreated cellulose is dissolved in lithium hydroxide/urea (LiOH/urea) and cellulose solution produced was immersed in distilled water bath. BKCP without treatment was also conducted for comparison purpose. The effects of acid hydrolysis pretreatment on solubility and crystallinity are investigated. Higher solubility of cellulose solution is achieved for treated samples. Cellulose II formation and crystallinity index of the cellulose membrane were determined by X-ray diffraction (XRD)

  19. The effect of acid hydrolysis pretreatment on crystallinity and solubility of kenaf cellulose membrane

    Science.gov (United States)

    Saidi, Anis Syuhada Mohd; Zakaria, Sarani; Chia, Chin Hua; Jaafar, Sharifah Nabihah Syed; Padzil, Farah Nadia Mohammad

    2015-09-01

    Cellulose was extracted from kenaf core pulp (KCP) by series of bleaching steps in the sequence (DEED) where D and E are referred as acid and alkali treatment. The bleached kenaf pulp (BKCP) is then pretreated with acid hydrolysis at room temperature for 1 and 3 h respectively. The pretreated cellulose is dissolved in lithium hydroxide/urea (LiOH/urea) and cellulose solution produced was immersed in distilled water bath. BKCP without treatment was also conducted for comparison purpose. The effects of acid hydrolysis pretreatment on solubility and crystallinity are investigated. Higher solubility of cellulose solution is achieved for treated samples. Cellulose II formation and crystallinity index of the cellulose membrane were determined by X-ray diffraction (XRD).

  20. Physical and mechanical properties of microcrystalline cellulose prepared from local agricultural residues

    International Nuclear Information System (INIS)

    Microcrystalline cellulose (MCC) was prepared from local agricultural residues, namely, bagasse, rice straw, and cotton stalks bleached pulps. Hydrolysis of bleached pulps was carried out using hydrochloric or sulfuric acid to study the effect of the acid used on the properties of produced microcrystalline cellulose such as degree of polymerization (DP), crystallinity index (CrI), crystallite size, bulk density, particle size, and thermal stability. The mechanical properties of tablets made from microcrystalline cellulose of the different agricultural residues were tested and compared to commercial grade MCC. The use of rice straw pulp in different proportions as a source of silica to prepare silicified microcrystalline cellulose (SMCC) was carried out. The effect of the percent of silica on the mechanical properties of tablets before and after wet granulation was tested

  1. Study on TEMPO-Mediated Selective Oxidation of Alkaline Natural Cellulose Pulp and Properties of Its Products

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; SUN Bin; ZHU Mei-fang

    2007-01-01

    It has been reported that natural cellulose(celluloseⅠ) can not be oxidized by TEMPO - NaOCl -NaBr system, one of TEMPO-mediated selective oxidantsystems, but regenerated cellulose(cellulose Ⅰ)can becompletely selectively oxidized. In the present work,natural cellulose pulp was treated with NaOH solution,which concentration is lower than 20 wt%. The alkalinecelluloses obtained were oxidized by TEMPO - NaOCl -NaBr system and the factors which influence the selectiveoxidation reaction rate have been investigated. Thestructure of the oxidized products has been characterizedby Fourier transform-infrared(FTIR), nuclear magenaticresonace(NMR) and wide angle X-ray diffraction(WAXD) methods, and their adsorption properties forCu2+ and Cd2+ in aqueous solutions have beenpreliminarily examined. The results show that after thealkaline treatment, the primary hydroxyl at C6 position ofnatural cellulose can be selectively oxidized to carboxylgroup in the reaction medium at pH 10.8, the oxidationrate becomes greater with the NaOH concentration andalkaline treatment time increasing. The alkaline treatmenthas a great effect on the crystal structure of naturalcellulose, but the crystal structure of alkaline cellulosekeeps almost unchanged after oxidation. The adsorptioncapacity is enhanced by introducing carboxyl groups intothe cellulose macromolecular chains.

  2. 阔叶木硫酸盐制浆和漂白中应用化学添加剂脱除抽提物%Using Additives for the Removal of Extractives in Kraft Pulping and Bleaching of Hardwood

    Institute of Scientific and Technical Information of China (English)

    胥成龙

    2004-01-01

    The effect of four additives (surfactants and dispersant) that were supplied by Hercules Chemicals Singapore Pte Ltd on kraft pulping and bleaching of Eucalyptus camaldulensis and Acacia mangium has been studied. The use of additives results in a more removal of extractives, and in a more uniform cook with lower screen rejects in eucalyptus, lower residual alkali, and in an improvement in brightness of eucalyptus pulps. At low additive charge level, a reduction of kappa number generated without clear loss of pulp yield in acacia cook.

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

    Directory of Open Access Journals (Sweden)

    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. Biocomposite of Cassava Starch Reinforced with Cellulose Pulp Fibers Modified with Deposition of Silica (SiO2 Nanoparticles

    Directory of Open Access Journals (Sweden)

    Joabel Raabe

    2015-01-01

    Full Text Available Eucalyptus pulp cellulose fibers were modified by the sol-gel process for SiO2 superficial deposition and used as reinforcement of thermoplastic starch (TPS. Cassava starch, glycerol, and water were added at the proportion of 60/26/14, respectively. For composites, 5% and 10% (by weight of modified and unmodified pulp fibers were added before extrusion. The matrix and composites were submitted to thermal stability, tensile strength, moisture adsorption, and SEM analysis. Micrographs of the modified fibers revealed the presence of SiO2 nanoparticles on fiber surface. The addition of modified fibers improved tensile strength in 183% in relation to matrix, while moisture adsorption decreased 8.3%. Such improvements were even more effective with unmodified fibers addition. This result was mainly attributed to poor interaction between modified fibers and TPS matrix detected by SEM analysis.

  5. In Vitro Osteogenic and Odontogenic Differentiation of Human Dental Pulp Stem Cells Seeded on Carboxymethyl Cellulose-Hydroxyapatite Hybrid Hydrogel.

    Directory of Open Access Journals (Sweden)

    Gabriella eTeti

    2015-10-01

    Full Text Available Stem cells from human dental pulp have been considered as an alternative source of adult stem cells in tissue engineering because of their potential to differentiate into multiple cell lineages.Recently, polysaccharide based hydrogels have become especially attractive as matrices for the repair and regeneration of a wide variety of tissues and organs. The incorporation of inorganic minerals as hydroxyapatite nanoparticles can modulate the performance of the scaffolds with potential applications in tissue engineering. The aim of this study was to verify the osteogenic and odontogenic differentiation of dental pulp stem cells (DPSCs cultured on a carboxymethyl cellulose—hydroxyapatite hybrid hydrogel. Human DPSCs were seeded on carboxymethyl cellulose—hydroxyapatite hybrid hydrogel and on carboxymethyl cellulose hydrogel for 1, 3, 5, 7, 14 and 21 days. Cell viability assay and ultramorphological analysis were carried out to evaluate biocompatibility and cell adhesion. Real Time PCR was carried out to demonstrate the expression of osteogenic and odontogenic markers. Results showed a good adhesion and viability in cells cultured on carboxymethyl cellulose—hydroxyapatite hybrid hydrogel, while a low adhesion and viability was observed in cells cultured on carboxymethyl cellulose hydrogel. Real Time PCR data demonstrated a temporal up-regulation of osteogenic and odontogenic markers in dental pulp stem cells cultured on carboxymethyl cellulose—hydroxyapatite hybrid hydrogel. In conclusion, our in vitro data confirms the ability of DPSCs to differentiate toward osteogenic and odontogenic lineages in presence of a carboxymethyl cellulose—hydroxyapatite hybrid hydrogel. Taken together, our results provide evidence that DPSCs and carboxymethyl cellulose—hydroxyapatite hybrid hydrogel could be considered promising candidates for dental pulp complex and periodontal tissue engineering.

  6. HE EFFECT OF TRANSITION METAL IONS-IRON ON HYDROGEN PEROXIDE BLEACHING

    Institute of Scientific and Technical Information of China (English)

    Yumeng Zhao; Shuhui Yang; Liang Sheng; Yonghao Ni

    2004-01-01

    Hydrogen peroxide bleaching has been extensively used in high-yield pulp bleaching. Unfortunately,hydrogen peroxide can be decomposed under alkaline condition, especially when transition metal ions exit. Experiments show that the valence of transition metal ion is also responsible for the decomposition of hydrogen peroxide.Iron ions are present in two oxidation states, Fe2+ and Fe3+. They are both catalytically active to hydrogen peroxide decomposition. Because Fe3+ is brown, it can affect the brightness of pulp directly, it can also combine with phenol, forming complexes which not only are stable structures and are difficult to be removed from pulp, but also significantly affect the brightness of pulp because of their color.Sodium silicate and magnesium sulfate, when used together, can greatly decrease hydrogen peroxide decomposition. The optimum dosage of sodium silicate is about 0.1% (on solution) for Fe2+ and 0.25% (on solution) for Fe3+. Adding chelants such as DTPA or EDTA with stabilizers simultaneously can obviously improve pulp brightness. For iron ions, the chelate effect of DTPA is better than that of EDTA.Under acidic conditions, sodium hyposulfite and cellulose can reduce Fe3+ to Fe2+ effectively, and pulp brightness is improved greatly. Adding sodium thiosulfate simultaneously with magnesium sulfate,sodium silicate, and DTPA to alkaline peroxide solution can result in higher brightness of pulp.pH is a key parameter during hydrogen peroxide bleaching, the optimum pH value should be 10.5-12.

  7. Isolation and characterization of microcrystalline cellulose from oil palm biomass residue.

    Science.gov (United States)

    Mohamad Haafiz, M K; Eichhorn, S J; Hassan, Azman; Jawaid, M

    2013-04-01

    In this work, we successfully isolated microcrystalline cellulose (MCC) from oil palm empty fruit bunch (OPEFB) fiber-total chlorine free (TCF) pulp using acid hydrolysis method. TCF pulp bleaching carried out using an oxygen-ozone-hydrogen peroxide bleaching sequence. Fourier transform infrared (FT-IR) spectroscopy indicates that acid hydrolysis does not affect the chemical structure of the cellulosic fragments. The morphology of the hydrolyzed MCC was investigated using scanning electron microscopy (SEM), showing a compact structure and a rough surface. Furthermore, atomic force microscopy (AFM) image of the surface indicates the presence of spherical features. X-ray diffraction (XRD) shows that the MCC produced is a cellulose-I polymorph, with 87% crystallinity. The MCC obtained from OPEFB-pulp is shown to have a good thermal stability. The potential for a range of applications such as green nano biocomposites reinforced with this form of MCC and pharmaceutical tableting material is discussed. PMID:23499105

  8. 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. PMID:27178917

  9. PRODUCTION OF NANOCELLULOSE FROM NATIVE CELLULOSE – VARIOUS OPTIONS UTILIZING ULTRASOUND

    OpenAIRE

    Shree Prakash Mishra,; Anne-Sophie Manent,; Bruno Chabot; Claude Daneault

    2011-01-01

    In this study three different ways of applying ultrasound for the production of nanocellulose from native cellulose were explored. In the first option bleached hardwood kraft pulp was oxidized with the ultrasound (US) assisted TEMPO/NaBr/NaOCl-system (US-TEMPO-system) followed by mechanical separation of nanocellulose. The pulp oxidized by the US-TEMPO-system had higher carboxyls content and ca. 10% increase in nanocellulose yield when compared to the TEMPO-system without sono catalysis. In t...

  10. Lignin Peroxidase Activity Is Not Important in Biological Bleaching and Delignification of Unbleached Kraft Pulp by Trametes versicolor

    OpenAIRE

    Archibald, Frederick S.

    1992-01-01

    The discovery in 1983 of fungal lignin peroxidases able to catalyze the oxidation of nonphenolic aromatic lignin model compounds and release some CO2 from lignin has been seen as a major advance in understanding how fungi degrade lignin. Recently, the fungus Trametes versicolor was shown to be capable of substantial decolorization and delignification of unbleached industrial kraft pulps over 2 to 5 days. The role, if any, of lignin peroxidase in this biobleaching was therefore examined. Sever...

  11. Polyoxometalates in Oxidative Delignification of Chemical Pulps: Effect on Lignin

    Directory of Open Access Journals (Sweden)

    Kolby Hirth

    2010-03-01

    Full Text Available Chemical pulps are produced by chemical delignification of lignocelluloses such as wood or annual non-woody plants. After pulping (e.g., kraft pulping, the remaining lignin is removed by bleaching to produce a high quality, bright paper. The goal of bleaching is to remove lignin from the pulp without a negative effect on the cellulose; for this reason, delignification should be performed in a highly selective manner. New environmentally-friendly alternatives to conventional chlorine-based bleaching technologies (e.g., oxygen, ozone, or peroxide bleaching have been suggested or implemented. In an attempt to find inorganic agents that mimic the action of highly selective lignin-degrading enzymes and that can be applicable in industrial conditions, the researchers have focused on polyoxometalates (POMs, used either as regenerable redox reagents (in anaerobic conditions or as catalysts (in aerobic conditions of oxidative delignification. The aim of this paper is to review the basic concepts of POM delignification in these two processes.

  12. 高锰酸钾活化麦草浆过氧化氢漂白的研究%A study on hydrogen peroxide bleaching of wheat straw pulp activated by potassium permanganate

    Institute of Scientific and Technical Information of China (English)

    郭星; 张安龙; 罗清; 赵登

    2014-01-01

    探讨了高锰酸钾对Soda-AQ法麦草浆过氧化氢漂白的活化作用。结果表明,高锰酸钾是一种强氧化剂,在酸性条件下可与纸浆中的木素反应,经高锰酸钾预处理后的纸浆具有很好的可漂性。通过分析比较MQDP和MDQP两种漂白流程,得出在高锰酸钾用量为1.0%时,采用MDQP漂白流程,纸浆得率损失较小,白度最高。%The activation of potassium permanganate was investigated in Soda-AQ hydrogenperoxide bleaching of wheat straw pulp. The results show that potassium permanganate serves very well as a strong oxidant. Under acidic conditions, potassium permanganate reacts with lignin in pulp and having a good bleachability after potassium permanganate pretreatment. By comparing bleaching sequence of MQDP and MDQP, when the dosage of potassium permanganate is 1.0%, using bleaching sequence of MDQP, pulp yield loss is smaller and getting the highest whiteness.

  13. Microfibrillated cellulose: Energy-efficient preparation techniques and applications in paper

    OpenAIRE

    Ankerfors, Mikael

    2015-01-01

    This work describes three alternative processes for producing microfibrillated cellulose (MFC; also referred to as cellulose nanofibrils, CNF) in which bleached pulp fibres are first pretreated and then homogenized using a high-pressure homogenizer. In one process, fibre cell wall delamination was facilitated by a combined enzymatic and mechanical pretreatment. In the two other processes, cell wall delamination was facilitated by pretreatments that introduced anionically charged groups into t...

  14. Possibility of Using Wood Pulp in the Preparation of Cement Composites

    Directory of Open Access Journals (Sweden)

    Kidalova Lucia

    2014-06-01

    Full Text Available Sustainable building materials are based on the use of renewable materials instead of non-renewable. Large group of renewable materials composes of plant fibres having high tensile strength are used as fillers into building material with reinforcement function of composite. This study aimed to establish the mechanical and physical properties of cement composites with organic fillers, such as wood pulp. Wood pulp cellulose is very interesting material as reinforcement in cement which contributes to a reduction of pollutants. Varying the producing technology (wood pulp and cement ratio in mixture it is possible to obtain composites with density from 940 to 1260 kgm-3 and with compressive strength from 1.02 to 5.44 MPa after 28 days of hardening. Based on the experimental results, cement composites with using unbleached wood pulp reach higher values than composites based on bleached wood pulp. Volume ratio of unbleached wood pulp in composites influences water absorbability of cement composites

  15. Possibility of Using Wood Pulp in the Preparation of Cement Composites

    Science.gov (United States)

    Kidalova, Lucia; Stevulova, Nadezda; Geffert, Anton

    2014-06-01

    Sustainable building materials are based on the use of renewable materials instead of non-renewable. Large group of renewable materials composes of plant fibres having high tensile strength are used as fillers into building material with reinforcement function of composite. This study aimed to establish the mechanical and physical properties of cement composites with organic fillers, such as wood pulp. Wood pulp cellulose is very interesting material as reinforcement in cement which contributes to a reduction of pollutants. Varying the producing technology (wood pulp and cement ratio in mixture) it is possible to obtain composites with density from 940 to 1260 kgm-3 and with compressive strength from 1.02 to 5.44 MPa after 28 days of hardening. Based on the experimental results, cement composites with using unbleached wood pulp reach higher values than composites based on bleached wood pulp. Volume ratio of unbleached wood pulp in composites influences water absorbability of cement composites

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

    OpenAIRE

    André Fredo; Celso E. B. Foelkel; Sônia M. B. Frizzo; Silva, Maria C. M.

    2009-01-01

    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, a...

  17. Removal of TOC and Color in Bleaching Effluents from Straw Pulp and Paper Mill by Fe0- H2O2 Process

    Institute of Scientific and Technical Information of China (English)

    YU Shui-li; LIU Ru-peng; LIU Ya-nan

    2006-01-01

    TOC and color in the bleaching effluent from straw pulp paper process could not reach draining standard after its treatment by a biochemical process. In this study, advanced treatment by integrated micro-electrolysis (Fe0) method and Fenton-like process was investigated under various conditions, i.e. pH, Fe/C ratio, initial H2O2 concentration and carrier gas. Results showed that Fe/C ratio(V/V =1.5), larger H2O2 dosage around 50 mg/L, lower pH(pH=3) turned out to be particularly efficient. Temperature was a key parameter, remarkably increasing reaction rates.Carrier air not only improved reaction efficiency, but also saved H2O2 dosage. Chlorinated organic compounds could be reductive dechlorinated by Fe0 reaction and oxidated by · OH produced from Fenton process. The combination of Fe0 and H2O2 reactions had been proved to be highly effective for the advanced treatment of such a type of wastewaters, and important advantages concerning the application in the study.

  18. The effect of wood supply and bleaching process on pulp brightness stability O efeito do tipo de madeira e do processo de branqueamento na estabilidade da alvura da polpa

    Directory of Open Access Journals (Sweden)

    Romildo Lopes Oliveira

    2006-06-01

    Full Text Available One hundred different 5.5-year-old Eucalyptus grandis x Eucalyptus urophylla wood clones were cooked to kappa number 15-17.5 and the resulting kraft pulps oxygen-delignified to kappa 9.5-11.5 under fixed conditions, except for chemical charges. Thirteen samples showing large variations in effective alkali requirement, pulp yield and O-stage efficiency and selectivity were selected for brightness reversion studies. These samples were bleached to 90-91% ISO by DEDD and DEDP sequences and their brightness stability and chemical characteristics determined. Heat reversion of the eucalyptus kraft pulps was strongly influenced by the wood supply, with brightness loss varying in the range of 2.1-3.6 and 0.8-1.7 %ISO for ODEDD and ODEDP bleached pulps, respectively. Pulps bleached by the ODEDP sequence showed reversion values 1.3-1.9 % ISO lower than those bleached by the ODEDD sequence. Pulp carbonyl content decreased by 35-40% during the final peroxide bleaching stage. Carbonyl and carboxyl groups correlated positively with brightness reversion, as did permanganate number and acid soluble lignin. Pulp final viscosity and metal and DCM extractives contents showed no significant correlation with brightness reversion. Pulping, oxygen delignification and ECF bleaching performances also showed no correlation with brightness reversion.Madeiras de 100 diferentes clones de Eucalyptus grandis e Eucalyptus urophylla, com aproximadamente 5,5 anos de idade, foram cozidas ao número kappa 15-17,5. As polpas kraft produzidas foram pré-deslignificadas com oxigênio ao número kappa 9,5-11,5, sob condições fixas. Treze polpas, que mostraram grandes variações na exigência da carga de álcali efetivo e rendimento no processo de polpação, seletividade e eficiência no estágio de Pré-O, foram selecionadas e branqueadas à alvura DE 90-91% ISO pelas seqüências DEDD e DEDP, para estudos de estabilidade de alvura e características químicas. A reversão de

  19. Microstructure and mechanical properties of gypsum composites reinforced with recycled cellulose pulp

    OpenAIRE

    Magaly Araújo Carvalho; Carlito Calil Júnior; Holmer Savastano Junior; Rejane Tubino; Michele Tereza Carvalho

    2008-01-01

    The use of waste fibers for the reinforcement of brittle matrices is considered opportune for the sustainable management of urban solid residues. This paper examines the microstructure and mechanical properties of a composite material made of gypsum reinforced with cellulose fibers from discarded Kraft cement bag. Two different kinds of gypsum were used, natural gypsum (NG) and recycled gypsum (RG), both with an addition of 10% by mass of limestone. For the production of samples, slurry vacuu...

  20. 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...

  1. Cellulose

    Science.gov (United States)

    Cellulose properties and structure are reviewed, with a primary focus on crystal structure and polymorphy. This focus highlights the conversion from cellulose I to cellulose II, which converts the molecules to being all parallel to each other in the crystal to being antiparallel. This has been co...

  2. Processing pharmaceutical grade microcrystalline cellulose from groundnut husk: Extraction methods and characterization

    Directory of Open Access Journals (Sweden)

    Ohwoavworhua Frank

    2009-01-01

    Full Text Available Microcrystalline cellulose (MCC is an important ingredient in pharmaceutical, food, cosmetic and other industries. In this work, MCC was prepared from the alpha cellulose content of groundnut husk, a renewable natural resource that has no industrial utilization yet. The effects of pulping methods (sodium hydroxide and multistage pulping and varying bleaching time on yield and amorphous properties of obtained alpha cellulose were examined. The prepared MCC (groundnut husk-MCC was characterized using scanning electron microscopy (SEM, infrared spectroscopy (FTIR, X-ray powder diffractometer (X-RPD, differential scanning calorimetry (DSC and compared with commercial-grade MCC. The results showed that complete pulping was achieved only by the use of the multistage pulping method and its yield was 15%. It was also found that the duration of bleaching affected the polymeric form of the processed alpha cellulose and hence, it is suggested that X-ray diffraction analysis should form an in-process check in the production of cellulose to ensure batch-to-batch consistency and performance. It was concluded that GH-MCC compared favourably with the commercial-grade MCC as well as conform to official specifications for MCC in the British Pharmacopoeia.

  3. 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)

  4. Short Process ECF Bleaching of Corn Stalk Rind Pulp by Organic Acid Biorefinery%有机酸生物炼制玉米秸秆皮浆短流程ECF漂白特性

    Institute of Scientific and Technical Information of China (English)

    黄萍; 翟华敏

    2012-01-01

    为寻求合理白度、节省资源、节能减排的漂白途径,研究了有机酸玉米秸秆皮生物炼制浆(OABCSRP)的短流程碱处理-二氧化氯-二氧化氯(ED1D2)无元素氯(ECF)漂白特性.结果表明:碱处理对OABCSRP具有良好的脱木质素选择性,是后续二氧化氯(D)漂白的重要基础,在浆浓10.0%(质量分数)、温度70℃、时间1.5h和用碱量4.0%的条件下碱处理,可获得率为95.4%、脱木质素率23.5%、黏度115 mPa·s、白度44.2%(ISO)的纸浆;在碱处理过程中浆料中木质素和碳水化合物中的酯键发生了水解;ECF短流程ED1D2在4.0%NaOH及总ClO2用量3.6%条件下,经ED1D2漂白后,可获积累得率为88.0%、黏度124 mPa·s、白度74.7%(ISO)的优良纸浆.%To obtain a bleaching process with a reasonable brightness, low consumption of fiber resource and energy, the bleaching properties of organic acid biorefinery corn stalk rind pulp (OABCSRP) by a short ECF bleaching process of ED1D2 were investigated in present study. The results indicates alkali extraction is high selective on delignification of OABCSRP, and the extraction is a foundation for next effective D1D2 bleaching stages. A pulp with 95.4% yield, 23.5% delignification ratio, 115 mPa·s viscosity and 44.2% ISO brightness was obtained when pulp with 10.0% concentration was treated by 4.0% NaOH for 1. 5 h at 70 ℃. Interesting findings revealed that the ester linkages between lignin and carbohydrate were hydrolyzed in the extraction process. The pulp with an accumulated yield 88.0% , 124 mPa·s and brightness 74.7% ISO respectively when 4. 0% NaOH and 3.6% C1O2 dosages were applied in ED1D2 bleaching. ED1D2 short bleaching process was suitable for OABCSRP bleaching to produce cultural papers.

  5. Production of Cellulosic Polymers from Agricultural Wastes

    Directory of Open Access Journals (Sweden)

    A. U. Israel

    2008-01-01

    Full Text Available Cellulosic polymers namely cellulose, di-and triacetate were produced from fourteen agricultural wastes; Branch and fiber after oil extraction from oil palm (Elais guineensis, raffia, piassava, bamboo pulp, bamboo bark from raphia palm (Raphia hookeri, stem and cob of maize plant (Zea mays, fruit fiber from coconut fruit (Cocos nucifera, sawdusts from cotton tree (Cossypium hirsutum, pear wood (Manilkara obovata, stem of Southern gamba green (Andropogon tectorus, sugarcane baggase (Saccharium officinarum and plantain stem (Musa paradisiaca. They were subjected to soda pulping and hypochlorite bleaching system. Results obtained show that pulp yield from these materials were: 70.00, 39.59, 55.40, 86.00, 84.60, 80.00, 40.84, 81.67, 35.70, 69.11, 4.54, 47.19, 31.70 and 52.44% respectively. The pulps were acetylated with acetic anhydride in ethanoic acid catalyzed by conc. H2SO4 to obtain cellulose derivatives (Cellulose diacetate and triacetate. The cellulose diacetate yields were 41.20, 17.85, 23.13, 20.80, 20.23, 20.00, 39.00, 44.00, 18.80, 20.75, 20.03, 41.20, 44.00, and 39.00% respectively while the results obtained as average of four determinations for cellulose triacetate yields were: 52.00, 51.00, 43.10, 46.60, 49.00, 35.00, 40.60, 54.00, 57.50, 62.52, 35.70. 52.00, 53.00 and 38.70% respectively for all the agricultural wastes utilized. The presence of these cellulose derivatives was confirmed by a solubility test in acetone and chloroform.

  6. Simultaneous production of α-cellulose and furfural from bagasse by steam explosion pretreatment

    Directory of Open Access Journals (Sweden)

    Vittaya Punsuvon

    2008-02-01

    Full Text Available Sugar cane bagasse was pretreated by steam explosion for the simultaneous production of furfural and α-cellulose pulp. The components of bagasse were fractionated after steam explosion. The details of the process are as follows. Bagasse was soaked in water for one night and steamed at temperatures varying between 206 and 223 C for 4 minutes. The steam exploded pulp was strained and washed with hot water to yield a liquor rich in hemicellulose-derived mono- and oligosaccharides. The remaining pulp was delignified by alkali for 120 minutes at 170C using, separately, NaOH load of 15, 20 and 25% of weight of the pulp. The delignified pulp was further bleached twice with 4% H2O2 charge of weight of the pulp to produce high α-cellulose pulp. The water liquor was evaporated and further hydrolysed and dehydrated with diluted H2SO4 in a stainless steel reactor to produce furfural. The result shows that the optimal pretreatment of steam explosion for 4 min at 218C leads to the yield of α-cellulose pulp at 193-201 g∙kg-1 of the original bagasse, and that furfural can be produced from xylose present in the liquor with a maximum conversion factor of 0.16.

  7. BLEACHING OF SULFONATED CMP FROM BIO-TREATED WHEAT STRAW

    Institute of Scientific and Technical Information of China (English)

    HongYu; MenghuaQin; XuemeiLu; YinboQu; PeijiGao

    2004-01-01

    Wheat straw chemi-mechanical pulp was pretreated with a crude xylanase which was secreted by white rot fungus Phanerochaete Chrysosporium prior to hydrogen peroxide bleaching. The process of xylanase pretreatment and hydrogen peroxide bleaching was optimized. The xylanase treated pulp achieved a brightness gain of 5.8% ISO over the untreated pulp. The xylanase treatment was found to liberate reducing sugars and facilitating lignin removal. Fiber morphology of pulp treated with xylanase was also studied by SEM.

  8. Microstructure and mechanical properties of gypsum composites reinforced with recycled cellulose pulp

    Directory of Open Access Journals (Sweden)

    Magaly Araújo Carvalho

    2008-12-01

    Full Text Available The use of waste fibers for the reinforcement of brittle matrices is considered opportune for the sustainable management of urban solid residues. This paper examines the microstructure and mechanical properties of a composite material made of gypsum reinforced with cellulose fibers from discarded Kraft cement bag. Two different kinds of gypsum were used, natural gypsum (NG and recycled gypsum (RG, both with an addition of 10% by mass of limestone. For the production of samples, slurry vacuum de-watering technique followed by pressing was evaluated revealing to be an efficient and innovative solution for the composites under evaluation. The composite was analyzed based on flexural strength tests, scanning electron microscopy (SEM imaging, secondary electron (SE detection, and pseudo-adiabatic calorimetry. The morphology of the fractured surfaces of flexural test samples revealed large gypsum crystals double the original size surrounding the fibers, but with the same overall aspect ratio. Natural fibers absorb large amounts of water, causing the water/gypsum ratio of the paste to increase. The predominance of fiber pullout, damaged or removed secondary layers and incrusted crystals are indicative of the good bonding of the fiber to the gypsum matrix and of the high mechanical resistance of composites. This material is a technically better substitute for the brittle gypsum board, and it stands out particularly for its characteristics of high impact strength and high modulus of rupture.

  9. 非木材纤维制浆清洁生产技术方案--洗筛漂工段%Clean production of non-wood ifber pulping--Washing, screening and bleaching section

    Institute of Scientific and Technical Information of China (English)

    汪骏

    2014-01-01

    An important reason of affecting the development of paper industry is the shortage of raw resources, and the shortage of raw materials is largely caused by structural contradictory between papermaking materials and ifber resources. Taken the washing, screening and bleaching section of reed pulp production line as an example, the technology and the equipment for an advanced cleaning production line was introduced in this article to realize the comprehensive recycling utilization of biomass. According to the requirements speciifed in The Evaluation Index System of Cleaning Production and Circular Economy in Pulp and Paper Industry, the technical plan was put forward on washing, screening and bleaching section in reed raw material pulping system.%影响造纸工业发展的一个重要原因是原料资源短缺,我国原料资源短缺在很大程度上是造纸原料结构与纤维资源结构之间的矛盾。本文以苇浆生产线洗筛漂工段为例,介绍采用先进和清洁生产的工艺技术和设备,以最大限度地实现生物质的综合循环使用。按照制浆造纸行业清洁生产评价指标体系和循环经济的要求,提出了芦苇原料制浆洗筛漂工段清洁生产技术方案。

  10. Influence of H2SO4 as Activator to ClO2 on the Bleaching Effects

    OpenAIRE

    Xingxiang Ji; Jiachuan Chen; Guihua Yang,; Zhong Jian Tian

    2012-01-01

    In this study, we show that chlorine dioxide activated by 4% Hydrochloric Acid Solution (HCl) has the same bleaching effects as that by sulfuric acid (H2SO4). Chlorine dioxide is an important bleaching agent in ECF bleaching. Stable chlorine dioxide in conjunction with Hydrochloric Acid Solution (HCl) activation in a certain proportion can be applied in the process of pulp bleach with a bleaching result of environment friendly, positive brightness stability, low pollutant bleach and pulp brig...

  11. Isolation and Characterization of Cellulose Nanofibers from Gigantochloa scortechinii as a Reinforcement Material

    Directory of Open Access Journals (Sweden)

    Chaturbhuj K. Saurabh

    2016-01-01

    Full Text Available Cellulose nanofibers (CNF were isolated from Gigantochloa scortechinii bamboo fibers using sulphuric acid hydrolysis. This method was compared with pulping and bleaching process for bamboo fiber. Scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis were used to determine the properties of CNF. Structural analysis by FT-IR showed that lignin and hemicelluloses were effectively removed from pulp, bleached fibers, and CNF. It was found that CNF exhibited uniform and smooth morphological structures, with fiber diameter ranges from 5 to 10 nm. The percentage of crystallinity was significantly increased from raw fibers to cellulose nanofibers, microfibrillated, along with significant improvement in thermal stability. Further, obtained CNF were used as reinforcement material in epoxy based nanocomposites where tensile strength, flexural strength, and modulus of nanocomposites improved with the addition of CNF loading concentration ranges from 0 to 0.7%.

  12. PULPING PROPERTIES OF KRAFT PULP OF NIGERIAN-GROWN KENAF (HIBISCUS CANNABINUS L.

    Directory of Open Access Journals (Sweden)

    Abiodun Oluwafemi Oluwadare

    2011-02-01

    Full Text Available This study was centered on finding a locally sourced alternative to imported long-fibre pulp for Nigerian pulp and paper mills. Fibre characteristics, chemical composition, and paper properties of pulp handsheets at different levels of kappa number and freeness in the range of 10 oSR and 62 oSR were evaluated using air-dried bast fibre obtained from decorticated kenaf plants grown in southern guinea savanna near Jebba, Nigeria. Kenaf bast fibre compared well with softwood, with an average fibre length of 2.90 mm, a flexibility ratio of 57%, and a Runkel ratio of 0.76. Ash, lignin, and pentosan contents were 0.6%, 12.5%, and 10.6%, respectively, while the cellulose content was 55.5%. Under alkali charge of 15.0 and, sulphidity of 17.5 with constant temperature, cooking time, and liquor-to-fibre ratio of 4.5:1, the screen yield was between 48.8 to 52.8 % with kappa number 12.04 to 20.5. Unbleached pulpsheets at kappa number between 15 and18.5 and pulp freeness 55 oSR and bleached pulp freeness between 148 and 336 mLs had better quality paper in terms of overall pulpsheet strength properties.

  13. Pulping of the giant leucaena wood. I. Pulping by the kraft process

    Energy Technology Data Exchange (ETDEWEB)

    Usami, K.; Ogino, T.; Takano, I.; Shimada, K.; Nishida, A.

    1980-01-01

    Cooking of Leucaena latisiliqua with kraft liquor (30% sulfidity as Na/sub 2/O) at 160 degrees gave 59.1% pulp with Kappa number 59.0 and Hunter brightness 19.9. The strength properties of pulp were comparable to those of beech pulp. It was confirmed that the extractives remaining in the bleached pulp adversely affect the color reversion.

  14. 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.

  15. Control of the accumulation of non-process elements and organic compounds in pulp mills with bleach filtrate reuse. Quarterly report, October--December 1996

    Energy Technology Data Exchange (ETDEWEB)

    Frederick, W.J.; Laver, M.L.; Rorrer, G.L.

    1996-12-31

    A portion of each filtrate sample was freeze-dried and the resulting solids were analyzed for ash content. Adsorption experiments with calcium and barium were carried at 70{degrees}C in a temperature controlled incubator under continuous mixing in order to simulate the environment experienced by brownstock as it moves through the Q stage. In the calcium experiments, it was difficult to accurately determine the calcium adsorbed on the pulp by measuring the depletion of calcium in the aqueous phase. Consequently, the technique was modified. In the modified technique, the calcium-adsorbed pulp is acid washed again to release the calcium. The calcium concentration in the washings is measured, and the calcium adsorbed on the pulp is estimated by material balance. Measurement of calcium adsorption on the brownstock pulp fibers from the L-P/Samoa mill have been obtained.

  16. STUDY ON FORMAMIDINE SULPHINIC ACID BLEACHING OF POPLAR APMP

    Institute of Scientific and Technical Information of China (English)

    Meiyun Zhang; Zhaoqing Lu

    2004-01-01

    Bleaching of poplar APMP with Formamidine sulphinic acid (FAS) was investigated in this paper.The effects of FAS charges, ratio of treatment on the brightness gain, color reduction and pulp strength were studied. A single-stage FAS bleaching was optimized. Under the conditions of 10 % pulp consistency, 60 minutes time and 70℃ reaction temperature and 0.6 %, FAS (on 0.d.pulp), ratio of FAS to NaOH was 2, we produced a bleached pulp with a brightness of 62.3 %(SBD), a brightness gain of 9.2 units.

  17. Palm rachis micro-ifbrillated cellulose and oxidized micro-ifbrillated cellulose for improving paper sheets properties of unbeaten softwood and bagasse pulps%用枣椰树叶轴微细纤维素和氧化微细纤维素来改善纸张性能

    Institute of Scientific and Technical Information of China (English)

    彭金勇

    2015-01-01

    Bleached palm rachis pulp pretreated with xylanase enzymes was used for isolation of micro-fibrillated cellulose (MFC) and TEMPO-oxidized MFC (TMFC) by ultraifne grinding. The isolated MFC and TMFC were used at ratios from 2.5% to 20% for improving strength properties of paper sheets prepared from unbeaten softwood and bagasse pulps. The retention of micro-ifbrillated cellulose in paper sheets was also estimated. The results showed that MFC or TMFC brought about an increase in density, wet and dry tensile strength, tear resistance, and a decrease in air permeability of paper sheets prepared from unbeaten softwood or bagasse. However, usual beating of softwood ifbers was much more effective in improving strength properties of softwood paper sheets than addition of micro-ifbrillated cellulose. On the other hand, the improvement in strength properties of bagasse paper sheets as a result of MFC or TMFC addition was generally higher than that resulted from beating of bagasse pulp. Use of TMFC with unbeaten softwood or bagasse ifbers resulted generally in better improvement in tensile strength (wet and dry) than in case of using MFC.%通过木聚糖酶预处理以及轻微磨浆处理,漂白枣椰树叶轴浆用来分离制备微细纤维素(MFC)和四甲基哌啶氧化微细纤维素(TMFC)。分离后的MFC和TMFC用来改善未打浆针叶木浆和甘蔗渣浆抄造的纸张的强度性能,添加比例从2.5%增加到20%,并且对MFC的留着也进行了估测。结果显示,MFC和TMFC的添加能够提高未打浆针叶木浆和甘蔗渣浆抄造的纸张的紧度、干湿抗张强度、撕裂强度以及降低纸张的透气度。但是,在改善针叶木浆纸张强度性能方面,通常的打浆操作比添加微细纤维素更加有效。另一方面,在改善甘蔗渣浆纸张强度性能方面,添加MFC和TMFC比通常的打浆操作更加有效。并且,在针叶木浆中或者甘蔗渣浆中添加TMFC对抗张强度(干强度和湿

  18. OPTIMIZATION OF SODA PULPING PROCESS OF LIGNO-CELLULOSIC RESIDUES OF LEMON AND SOFIA GRASSES PRODUCED AFTER STEAM DISTILLATION

    Directory of Open Access Journals (Sweden)

    Harjeet Kaur

    2011-02-01

    Full Text Available Sofia (Cymbopogon martini, and lemon (Cymbopogon flexuosus grasses, are exclusively cultivated for extraction of important lemongrass and palma rosa oils. Lignocellulosic residue (LCR of sofia and lemon grasses left after steam distillation can successfully be used for the production of chemical grade pulp. Steam distillation mitigates the problem of mass transfer, and facilitates the faster penetration of cooking liquor by leaching out a part of extraneous components. Sofia grass produces a pulp yield of 43.7% of kappa number 20 at an active alkali dose of 14% (as Na2O, maximum cooking temperature of 160 oC and cooking time 90 min. Likewise, lemon grass produces a pulp yield of 41.4% of kappa number 12.5 under the same conditions except temperature (150 oC by a soda pulping process. Addition of 0.1% AQ at optimum cooking conditions reduces kappa number by 26 and 8% for sofia and lemon grasses with insignificant increase in pulp yield i.e. 0.2 and 0.4% for sofia and lemon grasses, respectively. The mechanical strength properties of lemon grass soda-AQ pulp are better than sofia grass. Bauer-McNett fiber classification further validates that +20 fractions are more (62.63% in lemon grass than in sofia grass (42.72%.

  19. PEROXIDE BLEACHING OF LOW-FREENESS TMP

    Institute of Scientific and Technical Information of China (English)

    Zhong Liu; Y. Ni; Z. Li; G. Court

    2004-01-01

    Peroxide bleaching is an essential unit operation to produce value-added mechanical pulp-based paper grade. In this paper, we presented the results from peroxide bleaching of low-freeness TMP for the production of SC paper. Two aspects were addressed; the effect of pulp strength and the formation of anionic trashes. The strength properties,such as tensile, burst and zero-span tensile, are improved after the peroxide bleaching process. The amount of anionic trashes formed is almost proportional to the hydrogen peroxide charge.

  20. 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. PMID:15935655

  1. Geração de finos no branqueamento de pasta kraft de eucalipto e seu efeito nas propriedades do papel Genarations of fines in eucalyptus kraft pulp bleaching and their effect on paper properties

    Directory of Open Access Journals (Sweden)

    Jaqueline Silveira Comelato

    2013-02-01

    Full Text Available Este trabalho teve por objetivo avaliar a quantidade de finos gerada por diferentes reagentes de branqueamento e seu efeito nas propriedades físicas e mecânicas da celulose kraft de eucalipto. A polpa foi branqueada por quatro sequências diferentes. Parte das amostras foi classificada em equipamento Bauer-McNett, sendo a parte não classificada (global refinada para 40 ºSR, em moinho laboratorial PFI. As duas maiores porções de cada amostra proveniente da classificação foram também refinadas com o mesmo número de revoluções que a sua amostra global. Realizaram-se ensaios físicos e mecânicos das amostras refinadas, e suas fibras foram analisadas em equipamento FQA (Fiber Quality Analyser, antes e depois do refino. A maior quantidade de finos foi observada nas polpas refinadas e na sequência-referência. Os resultados de tração foram mais elevados e significativos nas amostras globais; as polpas classificadas não apresentaram diferença entre si, sendo atribuída a maior resistência à tração na presença de finos. A resistência ao rasgo foi afetada pelo comprimento das fibras e não pelo teor de finos. Os maiores valores de ascensão capilar Klemm ocorreram nas amostras classificadas em razão da ausência de finos e do maior comprimento de fibras.The objective of this work was to evaluate the generation of fines by different bleaching reagents and its effect on physical and mechanical properties of eucalyptus kraft pulp. The pulp was bleached by four different sequences. Some of these samples was classified in Bauer-McNett equipment. The unclassified part of the pulp (global was refined to 40ºSR in a laboratory PFI mill. The two major classified portions of each sample were also refined at the same revolutions as its global sample. Physical and mechanical tests were performed for both classified and unclassified samples, and their fibers were analyzed in FQA (Fiber Quality Analyzer, before and after refining.The greater

  2. Impact of kaolin filler on physical and mechanical paper properties formed by ECF pulp

    OpenAIRE

    Ivan Rodrigues dos Santos; Gustavo Ventorim; José Cláudio Caraschi; Jaqueline Silveira Comelato Favaro

    2014-01-01

    The paper industry is the main global consumer of kaolin. It is mostly used as paper filler, due to its lower cost as compared to pulp cost. Color removal process from pulp - chemical bleaching - determines final pulp's characteristics. Effort has been made to make possible to obtain less toxic bleaching processes. This study aims to evaluate the influence of three bleaching sequences, on kaolin retention and paper properties. Industrial eucalyptus kraft pulp, oxygen pre-delignified, was blea...

  3. Isolation of cellulose microfibrils - An enzymatic approach

    Directory of Open Access Journals (Sweden)

    Sain, M.

    2006-11-01

    Full Text Available Isolation methods and applications of cellulose microfibrils are expanding rapidly due to environmental benefits and specific strength properties, especially in bio-composite science. In this research, we have success-fully developed and explored a novel bio-pretreatment for wood fibre that can substantially improve the microfibril yield, in comparison to current techniques used to isolate cellulose microfibrils. Microfibrils currently are isolated in the laboratory through a combination of high shear refining and cryocrushing. A high energy requirement of these procedures is hampering momentum in the direction of microfibril isolation on a sufficiently large scale to suit potential applications. Any attempt to loosen up the microfibrils by either complete or partial destruction of the hydrogen bonds before the mechanical process would be a step forward in the quest for economical isolation of cellulose microfibrils. Bleached kraft pulp was treated with OS1, a fungus isolated from Dutch Elm trees infected with Dutch elm disease, under different treatment conditions. The percentage yield of cellulose microfibrils, based on their diameter, showed a significant shift towards a lower diameter range after the high shear refining, compared to the yield of cellulose microfibrils from untreated fibres. The overall yield of cellulose microfibrils from the treated fibres did not show any sizeable decrease.

  4. Coral Bleaching

    OpenAIRE

    Brinch, Anna; Hemmingsen, Sofie K. Møhlenfeldt; Rosenquist, Camilla; Tangaa, Stine Rosendal

    2010-01-01

    This review scrutinises the different cellular mechanisms and environmental stressors that lead to bleaching and discuss the numerous effects of these. Coral bleaching is characterized by corals losing their symbiotic zooxanthellae. Different environmental stressors, e.g. elevated sea temperatures, irradiance, changing salinity and increasing atmospheric CO2 induce damage in multiple sites of the photosynthetic apparatus of the zooxanthellae, leading to bleaching. Reactive oxygen species ...

  5. The effect of introducing ozone in elemental chlorine free bleaching of eucalyptus kraft pulp%桉木硫酸盐浆ECF漂白引入臭氧漂白的效果

    Institute of Scientific and Technical Information of China (English)

    刘红峰

    2015-01-01

    ZDED and DEDD sequences were applied on an oxygen-delignified eucalyptus (mixture of E.grandisand E.saligna) kraft pulp from Brazil. When ZDED and DEDD were compared, the displacement ratio calculated as the quantity of pure chlorine dioxide replaced by 1 kg ozone was found between 2.5 and 3.5 kg, as compared to 1.7 kg in theory—indicating that less wasting reactions occur in the ZDED sequence. The cellulose viscosity decreased substantially with the increase in the ozone charge (down to 50% at 0.8% ozone). Other typical characteristics of the ZDED pulps were easier beating, lower water retention value, higher proportion of kinked fibers, and lower wet zerospan breaking length (seen only at 0.8% ozone charge), as compared to DEDD. The viscosity loss due to the introduction of ozone in an elemental chlorine free sequence did not translate into a similar loss in strength. A comparison with the depolymerizing effect of cellulase suggests that the determining factoris not the extent of the drop in viscosity but rather the heterogeneity of the attack along the fibers. It is concluded that ozone oxidation of cellulose in the fibers would be rather homogeneous. Moreover, the appearance of morecurls and kinks would not be necessarily related to the viscosity loss. For example, a (2,2,6,6-tetramethylpiperidin-1-yl) oxidanyl (TEMPO) treated DEDD pulp, enriched in carboxyl groups, had more straight fibers than the original DEDD pulp, despite its lower viscosity. The presence of ionic groups would be a more important factor; the lower content in carboxyl groups in the ZDED pulps, compared to the DEDD pulps, could promote the easier formation of curl and kinks during the ZDED sequence.%巴西桉木浆(巨桉和柳桉)氧脱木素采用了ZDED和DEDD漂白工序.对比ZDED和DEDD漂白工序,计算出的置换率(1kg臭氧可代替的纯二氧化氯量)为2.5~3.5kg,而理论值为1.7kg,表明ZDED漂白工序中无效反应较少.随着臭氧用量的增加,纤维

  6. High biodegradation levels of 4,5,6-trichloroguaiacol by Bacillus sp. isolated from cellulose pulp mill effluent Altos níveis de biodegradação do 4,5,6-tricloroguaiacol por Bacillus sp. isolado de efluente de indústria de polpa de celulose

    OpenAIRE

    E.C. Tondo; C.W.S. Andretta; C. F. V. SOUZA; A.L. Monteiro; Henriques, J. A. P.; M. A. Z. Ayub

    1998-01-01

    An aerobic Gram positive spore-forming bacterium was isolated from cellulose pulp mill effluent. This microorganism, identified as Bacillus sp. and named IS13, was able to rapidly degrade the organic chlorinated compound 4,5,6-trichloroguaiacol (4,5,6-TCG) from a culture containing 50 mg/l, which corresponds to about 3x104 times the concentration found in the original effluent. The biodegradation of this compound, usually found in cellulose pulp mill effluents, was evaluated by spectrophotome...

  7. Alkaline xylan extraction of bleached kraft pulp-effect of extraction time on pulp chemical composition and physical properties%漂白硫酸盐浆的碱性木聚糖抽提对纸浆化学组分和物理性质的影响

    Institute of Scientific and Technical Information of China (English)

    林庆旭; 夏新兴

    2013-01-01

    In this pilot scale study, we examined the effects of alkaline extraction time on xylan removal, pulp and paper properties, and the consequences that need to be addressed when scaling up and intensifying the process. Alkaline extraction of bleached birch kraft pulp yields two fractions:pure polymeric xylan and pulp with reduced xylan content. Our results indicate that a similar amount of xylan can be extracted in 5 min as the amount obtained in 60 min. We found, however, that the shorter extraction time is beneficial to maintain the fiber and paper properties at an acceptable level. This pilot trial demonstrated that the washing procedure of the alkali-treated fibers must be selected with care to avoid causing mechanical damage to fibers and to avoid the loss of fines.%  研究了扩大和强化过程时碱抽提时间对木聚糖去除、纸浆和纸张性能及结果的影响。漂白桦木硫酸盐浆的碱抽提产生了两部分产物:纯木聚糖和木聚糖含量降低的纸浆。研究结果表明:抽提5m in得到的木聚糖量与抽提60m in得到的木聚糖量是相近的;在合理的范围内,缩短提取时间有利于保持纤维和纸张的性能;碱处理纤维的洗涤必须小心进行,以避免造成对纤维的机械损伤,以及细小纤维的流失。

  8. Application of a New Chelating Agent in Deinked Pulp Bleaching%新型螯合剂用于废纸脱墨浆的漂白

    Institute of Scientific and Technical Information of China (English)

    张海潮; 胡可信; 余聪

    2011-01-01

    采用柠檬酸钠、Na2SiO3对废纸脱墨浆进行预处理,并与EDTA预处理进行比较。结果表明,柠檬酸钠可替代EDTA作为纸浆漂白的螯合剂,废纸脱墨浆柠檬酸钠预处理的最佳工艺条件为:柠檬酸钠用量0.8%、预处理时间30min、预处理温度70℃、pH值8。采用柠檬酸钠预处理,并经过氧化氢一甲眯亚磺酸两段漂白,漂后纸浆白度可达77.67%ISO。%The sodium citrate and sodium silicate were used as another kind of chelating agent for the pre-treatment of DIP, which would be bleached by FAS(F) later, then contrasted with the chelation of EDTA. The results showed that the sodium citrate can be used as a chelating agent in place of EDTA. The optimum conditions for the pretreatment of DIP by the sodium citrate are as follows, sodium citrate dosage 0.8%, pre-treated time 30 min, pre-treated temperature 70℃, pH 8. By using the Sodium Citrate as the chelating agent, after the two-stage bleaching of P-F, the brightness of DIP could reach 77.67% (ISO).

  9. 用浸没式平板膜生物反应器处理草浆中段废水%Treatment of Washing/Bleaching Effluent from Straw Pulping Line by Using Immersed Flat Membrane Bioreactor

    Institute of Scientific and Technical Information of China (English)

    张安龙; 陈月; 赵小玲; 闫东峰

    2011-01-01

    The treatment of washing and bleaching wastewater of the wheat straw pulping line by using an immersed flat membrane bioreactor prepared in lab was studied. The experimental results showed that the CODCr, color, and SS removal efficiencies reach 90. 0%, 92.3% and 96.0% respectively. The effluent quality can meet the "the paper industry water pollution discharge standard" (GB3544-2008) requirements. The membrane pollution can be reduced by optimizing the operation parameters.%用自制浸没式平板膜生物反应器(MBR)对麦草浆中段废水进行处理,CODCr、色度和SS的去除率分别为90.0%、92.3%和96.0%,出水达到制浆造纸工业水污染物排放标准(GB3544-2008)的排放要求.处理过程中通过优化运行参数有效减缓了膜污染的发生.

  10. EFFECTS OF XYLAN IN EUCALYPTUS PULP PRODUCTION

    Directory of Open Access Journals (Sweden)

    Bianca Moreira Barbosa

    2016-06-01

    Full Text Available The search for a better use of wood in the pulp industry has fuelled interest in a more rational use of its components, particularly xylans. The impact of xylans removal and of xylans redeposition on pulp properties for tissue and P&W paper grades are discussed in this paper. Kraft pulp (15.6% xylans treatment with 10-70 g.L-1 NaOH resulted in pulps of 14.5-5.9% xylans. The treatments decreased pulp lignin and HexA contents and caused significant positive impact on subsequent oxygen delignification and ECF bleaching. Xylan removal decreased pulp beatability, water retention value and tensile index but increased drainability, water absorption capacity, capillarity Klemm and bulk. Overall, xylan depleted pulps showed almost ideal properties for tissue paper grade pulps. In a second step of the research, xylans extracted from unbleached (BXL and bleached eucalyptus pulps (WXL by cold caustic extraction (CCE were added to a commercial brown pulp in the oxygen delignification (O-stage and further bleached. Xylans deposition occurred at variable degree (up to 7% on pulp weight depending upon the O-stage reaction pH. Pulp bleachability was not impaired by WXL xylan deposition but slightly negatively affected by BXL xylans. Pulp beatability was improved by xylan deposition. The deposited xylans were quite stable across bleaching and beating, with the WXL xylans being more stable than the BXL ones. At low energy consumption, the deposited xylans improved pulp physical and mechanical properties. Xylans extraction by CCE with subsequent deposition onto pulp in the O-stage proved attractive for manufacturing high xylan P&W paper grades.

  11. 色谱法测定制浆造纸工业漂白废液中的草酸浓度%CHROMATOGRAPHIC METHOD FOR DETERMINATION OF OXALIC ACID IN BLEACHING FILTRATES FROM THE PULP AND PAPER INDUSTRY

    Institute of Scientific and Technical Information of China (English)

    洪枫; REIMANN Anders; J(O)NSSON Leif-j; NILVEBRANT Nils-olof

    2005-01-01

    Analysis and control of oxalic acid in bleaching filtrates has recently gained considerable attention in the pulp and paper industry due to problems with the formation of calcium oxalate scaling.Chromatographic methods,such as HPLC and ion chromatography(IC),are generally valuable as standard methods for determination of oxalic acid.In this study,a HPLC system equipped with an Aminex HPX-87H column was applied to determine oxalic acid in authentic bleaching filtrates.An established IC method based on separation with an anion-exchange column was used as reference method.The results showed that bleaching filtrates contain compounds interfering with the HPLC method.A strategy, dilution of the samples followed by treatment with activated carbon,was needed to obtain similar oxalic acid concentrations as provided by the reference method.The correlation(R=0.994) between the HPLC method and the IC method is described by the equation y=1.294 7x.The method improves the possibility for control of critical oxalic acid concentration in closed-loop bleaching streams.%近年来草酸钙(草酸垢)的形成在制浆造纸工业中造成诸多问题,因此如何分析及控制漂白废液中的草酸浓度就显得尤为重要.高效液相色谱和离子交换色谱等色谱法一般可以作为测定草酸的标准方法.本研究以一个基于阴离子交换柱的离子交换色谱法作为对照方法,利用一套配备了Aminex HPX-87H液相色谱柱的高效液相色谱系统测定漂白废液中的草酸浓度.结果显示,漂白废液中含有一些干扰高效液相色谱法测定的化合物.通过采用稀释样品后再经活性炭吸附的处理方法,可以得到较为满意的结果.分析发现高效液相色谱法与离子交换色谱(对照法)之间的相关性较好,相关系数为0.994.该方法的建立将有利于监控制浆造纸企业中闭路循环漂液中形成草酸钙时的临界草酸浓度.

  12. 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.

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

    Directory of Open Access Journals (Sweden)

    Qiang Zhao

    2010-02-01

    Full Text Available 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 consistency 10%, bleaching temperature 70oC, bleaching time 60 min when the charge of H2O2 was 4%, NaOH charge 2%, and molar ratio of TAED to H2O2 0.3. The pulp brightness gain reached 23.6% ISO with the optimized bleaching conditions. FTIR analysis indicated that the H2O2/TAED bleaching system can decrease carbonyl group further than that of conventional H2O2 bleaching, which contributed to the higher bleaching efficiency and final brightness. The H2O2/TAED bleaching had stronger oxidation ability on lignin than that of H2O2 bleaching.

  14. 漂白废报纸脱墨浆AKD施胶过程的湿部化学环境分析%Wet Chemical Environment Analysis of Alkyl Ketene Dimmers (AKD) Sizing of Bleached Waste Newspaper Deinked Pulp

    Institute of Scientific and Technical Information of China (English)

    韦黎; 曹云峰; 熊林根

    2011-01-01

    An L9(34)orthogonal test was designed to study the effects of AKD (alkyl ketene dimmers) charge, CS (cationic starch) charge, PCC (precipitated calcium carbonate) charge and CPAM (cationic polyacrylamide) charge on AKD sizing of bleached waste newspaper deinked pulp. And the optimal conditions were as follows: AKD dosage 0.4%, CS dosage 0.6%, PCC dosage 5% and CPAM dosage 0.03%. The variation tendency of sizing performance was essentially consistent with the Zeta potential value and cationic demand of furnish. In sizing process, Zeta potential and cationic demand of pulp was also an important factor, which was influential in the AKD sizing performance.%对漂白废报纸脱墨浆AXeD(烷基烯酮二聚物)施胶过程中AKD用量、CS(阳离子淀粉)用量、PCC(沉淀碳酸钙)用量和CPAM(阳离子聚丙烯酰胺)用量进行四因素三水平方差分析,当AKD用量为0.2%~0.4%(质量分数),CS用量为0.6%~1.0%,PCC用量为5%~15%,CPAM用量为0.03%-0.09%时,AKD施胶较为适宜工艺条件为:AKD用量0.4%,CS用量0.6%,PCC用量5%,CPAM用量0.03%。对纸浆动电特性的研究表明,成纸的施胶度基本与纸浆中的Zeta电位、浆料溶解电荷需求量的变化趋势一致。在施胶过程中,控制Zeta电位、浆料溶解电荷需求量也是影响AKD施胶效果的重要因素。

  15. 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...

  16. The Use of Alternate Ligno-cellulosic Raw Materials Banana (Musa sapientum Ankara (Calotropis procera and Pineapple (Ananas comosus in Handmade Paper & their Blending with Waste Paper.

    Directory of Open Access Journals (Sweden)

    Atul Kumar

    2013-09-01

    Full Text Available The studies were made to established suitability of lingo-cellulosic raw materials namely leaf fibreBanana (Musa Sapientum, bast fibre Ankara (Calotropis Procera, & leaf fibre Pineapple (Ananas Comosus for making pulps for handmade paper industry. This should help in providing a cost effective, good quality cellulosic raw material as an alternate to cost prohibitive traditionally used cotton hosiery waste traditionally used for manufacturing good quality handmade paper & it’s products. This will help in improving the cost economics & competitiveness of the Indian paper industry in the global market besides addressing the problems of environment & global warming. The aim of the research was to study the extraction, morphology, chemical composition and pulping of these fibres and relate these properties to the composite properties obtained with these fibres as reinforcement with short fibres viz. waste paper. For the pulp production to be feasible it is essential to use suitable pulping methods, which maximize the yield of pulp and introduce as low damage as possible to the fibres. The different pulping methods were applied to these fibre to get optimized strength properties papers. The Studies thus carried out provide useful information about the nature of these raw materials, suitable pulping & bleaching process to produce an eco-friendly handmade paper and converted products. The research work provides a good quality cost effective lingo-cellulosic raw material for handmade paper industries with a possibility of replacement of the expensive and traditionally used cotton hosiery waste.The paper thus produced using environmental friendly pulping and bleaching process is characterized for its strength properties like tensile, tear, bursting, folding endurance and other parameters. The effluents generated from pulping and bleaching of above ligno-cellulosic waste materials were characterized for various pollution parameters like Residual Alkali

  17. OPTIMIZING EUCALYPTUS PULP REFINING

    Institute of Scientific and Technical Information of China (English)

    Vail Manfredi

    2004-01-01

    This paper discusses the refining of bleached eucalyptus kraft pulp (BEKP).Pilot plant tests were carried out in to optimize the refining process and to identify the effects of refining variables on final paper quality and process costs.The following parameters are discussed: pulp consistency, disk pattern design, refiner speed,energy input, refiner configuration (parallel or serial)and refining intensity.The effects of refining on pulp fibers were evaluated against the pulp quality properties, such as physical strengths, bulk, opacity and porosity, as well as the interactions with papermaking process, such as paper machine runnability, paper breaks and refining control.The results showed that process optimization,considering pulp quality and refining costs, were obtained when eucalyptus pulp is refined under the lowest intensity and the highest pulp consistency possible. Changes on the operational refining conditions will have the highest impact on total energy requirements (costs) without any significant effect on final paper properties.It was also observed that classical ways to control the industrial operation, such as those based on drainage measurements, do not represent the best alternative to maximize the final paper properties neither the paper machine runability.

  18. Pollution prevention for the kraft pulp and paper industry

    Energy Technology Data Exchange (ETDEWEB)

    1992-09-01

    The document is an annotated bibliography of publications related to pollution prevention in the Kraft segment of the pulp and paper industry. It is organized by process area as follows: chip preparation, chemical pulping, pulp washing, bleaching, chemical recovery, recausticizing, power generation, wastewater treatment, papermaking, and general plant. The document contains 269 citations.

  19. Surface modification of cellulose by PCL grafts

    Energy Technology Data Exchange (ETDEWEB)

    Paquet, Olivier; Krouit, Mohammed; Bras, Julien [Laboratoire de Genie des Procedes Papetiers (UMR 5518 CNRS-CTP-INPG), Grenoble INP-Pagora, 461 Rue de la papeterie, F-38402 St Martin d' Heres (France); Thielemans, Wim [Driving Innovation in Chemistry and Chemical Engineering (DICE), School of Chemistry and Process and Environmental Research Division - Faculty of Engineering, University of Nottingham, University Park, Nottingham, NG7 2RD (United Kingdom); Belgacem, Mohamed Naceur, E-mail: Naceur.Belgacem@efpg.inpg.fr [Laboratoire de Genie des Procedes Papetiers (UMR 5518 CNRS-CTP-INPG), Grenoble INP-Pagora, 461 Rue de la papeterie, F-38402 St Martin d' Heres (France)

    2010-02-15

    Two cellulosic substrates (microcrystalline cellulose, MCC, and bleached kraft softwood pulps, BSK) were grafted by polycaprolactone (PCL) chains with different molecular weights, following a three-step procedure using non-swelling conditions in order to limit the reaction to their surface. First, one of the two OH PCL ends was blocked by phenyl isocyanate and the reaction product (adduct 1) was subsequently reacted with 2,4-toluene diisocyanate (adduct 2) to provide it with an NCO function, capable of reacting with cellulose. The ensuing PCL-grafted cellulosic materials were characterized by weight gain, elemental analysis, contact angle measurements, attenuated total reflexion-Fourier transform infrared (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and biodegradation tests. The modification was proven to occur by the presence of nitrogen atoms in the elemental analysis tests and XPS spectra of modified and soxhlet-extracted cellulose. The contact angle measurements have also shown that the surface became as hydrophobic as PCL itself. The polar component of the surface energy of cellulosic substrates before treatment was found to be about 32 and 10 mJ m{sup -2}, for MCC and BSK, respectively. This value vanished to practically zero after grafting with different PCLs. The strategy proposed in the present work is original since, to the best of our knowledge, this paper reports for the first time the chemical 'grafting onto' of the cellulose surface by PCL macromolecular structures, with the aim of obtaining fibre-matrix co-continuous fully sustainable and biodegradable composite materials.

  20. Bubble Size Control to Improve Oxygen-Based Bleaching: Characterization of Flow Regimes in Pulp-Water-Gas Three-Phase Flows

    Energy Technology Data Exchange (ETDEWEB)

    S.M. Ghiaasiaan and Seppo Karrila

    2006-03-20

    Flow characteristics of fibrous paper pulp-water-air slurries were investigated in a vertical circular column 1.8 m long, with 5.08 cm diameter. Flow structures, gas holdup (void fraction), and the geometric and population characteristics of gas bubbles were experimentally investigated, using visual observation, Gamma-ray densitometry, and flash X-ray photography. Five distinct flow regimes could be visually identified: dispersed bubbly, layered bubbly, plug, churn-turbulent, and slug. Flow regime maps were constructed, and the regime transition lines were found to be sensitive to consistency. The feasibility of using artificial neural networks (ANNs) for the identification of the flow regimes, using the statistical characteristics of pressure fluctuations measured by a single pressure sensor, was demonstrated. Local pressure fluctuations at a station were recorded with a minimally-intrusive transducer. Three-layer, feed-forward ANNs were designed that could identify the four major flow patterns (bubbly, plug, churn, and slug) well. The feasibility of a transportable artificial neural network (ANN) - based technique for the classification of flow regimes was also examined. Local pressures were recorded at three different locations using three independent but similar transducers. An ANN was designed, trained and successfully tested for the classification of the flow regimes using one of the normalized pressure signals (from Sensor 1). The ANN trained and tested for Sensor 1 predicted the flow regimes reasonably well when applied directly to the other two sensors, indicating a good deal of transportability. An ANN-based method was also developed, whereby the power spectrum density characteristics of other sensors were adjusted before they were used as input to the ANN that was based on Sensor 1 alone. The method improved the predictions. The gas-liquid interfacial surface area concentration was also measured in the study. The gas absorption technique was applied

  1. 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.

  2. STUDY ON FORMAMIDINE SULPHINIC ACID BLEACHING OF POPLAR APMP

    Institute of Scientific and Technical Information of China (English)

    MeiyunZhang; ZhaooinLu

    2004-01-01

    Bleaching of poplar APMP with Formamidinesulphinic acid (FAS) was investigated in this paper.The effects of FAS charges, ratio of treatment on thebrightness gain, color reduction and pulp strengthwere studied. A single-stage FAS bleaching wasoptimized. Under the conditions of 10 % pulpconsistency, 60 minutes time and 70~C reactiontemperature and 0.6 %, FAS (on 0.d.pulp), ratio ofFAS to NaOH was 2, we produced a bleached pulpwith a brightness of 62.3 %(SBD), a brightness gainof 9.2 units.

  3. XYLANASE PREBLEACHING ON NAOH-AQ WHEAT STRAW PULP

    Institute of Scientific and Technical Information of China (English)

    Caixia Li; Yongjun Deng; Ping Li; Guigan Fang; Shuchai Liu

    2004-01-01

    Before calcium hypochlorite bleaching (H) and chlorination,alkaline extraction, calcium hypochlorite three-stage-bleaching (CEH),we used a kind of hemicellulase, xylanase, to treat wheat straw pulp from Gaoyou Papermill.Xylanase pretreatment contained tow stages, the first stage was xylanase treatment, which was followed by alkaline extraction, the second stage. The xylanase could act on partial lignin and carbohydrate, chiefly xylan. The following alkaline extraction could dissolve something that could not be removed during the first stage. The result of pretreatment was to facilitate penetration of bleaching chemicals, to reduce effective chlorine consumption and to lower pollution loading of bleaching effluent. In the case of these two bleaching processes, the enzymatic pretreatment substantially enhanced the optical properties of the pulps. To calcium hypochlorite bleaching, strength properties of pulps were improved.

  4. High pressure pre-treatments promote higher rate and degree of enzymatic hydrolysis of cellulose

    OpenAIRE

    Ferreira, Ana R. F. C.; Figueiredo, Andreia B.; Evtuguin, Dmitry V.; Saraiva, Jorge A.

    2011-01-01

    The effect of high pressure (HP) pre-treatments on the subsequent enzymatic hydrolysis of cellulose from bleached kraft Eucalyptus globulus pulp by cellulase from Tricoderma viride was evaluated. Pressure pre-treatments of 300 and 400 MPa during 5–45 min, lead to both an increased rate and degree of hydrolysis, reaching values ranging from 1.5- to 1.9-fold, quantified by the formation of reducing sugars. Both the pressure and time under pressure influenced the enzymatic hydrosability of the c...

  5. Effects of Different Chemical by Adding the Bacterial Cellulose in Pulp%不同化学品对细菌纤维素配抄针叶木浆性能的影响

    Institute of Scientific and Technical Information of China (English)

    吕瑾; 王志杰; 刘叶; 石建博

    2012-01-01

    It studied the effects of different chemical for the electrochemical properties such as pH, electric conductivity rate, Zeta electric potential, demand of cation and so on, and the paper physical strength of the pulp with the bacterial cellulose. The result showed that adding Al2(SO4)3 and CPAM could change the eletrochemical properties of the pulp with the bacterial cellulose, and increas the physical strength of the paper obviously.%研究细菌纤维素配抄针叶木浆后添加不同化学品对浆料pH值、电导率、Zeta电位、阳离子需求量等电化学性质和成纸物理强度的影响。结果表明,细菌纤维素表面呈强负电性,在加了细菌纤维素的针叶木浆料系统中加入一定量的硫酸铝或CPAM,可以调节其电化学性能,使成纸物理强度增加更为明显.

  6. PRODUCTION OF NANOCELLULOSE FROM NATIVE CELLULOSE – VARIOUS OPTIONS UTILIZING ULTRASOUND

    Directory of Open Access Journals (Sweden)

    Shree Prakash Mishra,

    2011-11-01

    Full Text Available In this study three different ways of applying ultrasound for the production of nanocellulose from native cellulose were explored. In the first option bleached hardwood kraft pulp was oxidized with the ultrasound (US assisted TEMPO/NaBr/NaOCl-system (US-TEMPO-system followed by mechanical separation of nanocellulose. The pulp oxidized by the US-TEMPO-system had higher carboxyls content and ca. 10% increase in nanocellulose yield when compared to the TEMPO-system without sono catalysis. In the second option ultrasound pretreated pulp was oxidized using the TEMPO-system. Although there was no gain in carboxyls content in this process versus the oxidation with TEMPO-system without ultrasound treatment, a higher degree of fibrillation was obtained after ultrasound treatment. In the third case the TEMPO oxidized pulp was subjected to mechanical and ultrasound treatments for nanocellulose production. Under similar treatment time the subsequent ultrasound treatment achieved higher nanocellulose yield than the subsequent mechanical treatment. However, in comparison, the ultrasound treated nanocellulose had lower Rheometer Stresstech viscosity. Furthermore, it was observed that cellulose nanofibrils produced by ultrasound treatment were slightly thinner compared to those produced using the mechanical method.

  7. ULTRASOUND-CATALYZED TEMPO-MEDIATED OXIDATION OF NATIVE CELLULOSE FOR THE PRODUCTION OF NANOCELLULOSE: EFFECT OF PROCESS VARIABLES

    OpenAIRE

    Shree Prakash Mishra,; Jennifer Thirree; Anne-Sophie Manent,; Bruno Chabot; Claude Daneault

    2011-01-01

    In this study application of ultrasound in oxidizing native cellulose for the production of nanocellulose has been explored for the first time. Bleached hardwood kraft pulp was oxidized with an ultrasound (US) catalyzed 2,2,6,6-tetramethylepiperidin-1-oxyl (TEMPO) system (US-TEMPO-system) at five different temperatures – 5, 15, 25, 35, and 45°C and two pH ranges, 8.5-9.0 and 10.0-10.5 – to obtain the optimum reaction conditions. The reaction pH and temperature have significant effect on the k...

  8. XYLANASE PREBLEACHING ON NaOH-AQ WHEAT STRAW PULP

    Institute of Scientific and Technical Information of China (English)

    CaixiaLi; YongjunDeng; PingLi; GuiganFang; ShuchaiLiu

    2004-01-01

    Before calcium hypochlorite bleaching (H) and chlorination, alkaline extraction, calcium hypochlorite three-stage-bleaching (CEH),we used a kind of hemicellulase, xylanase, to treat wheat straw pulpfrom Gaoyou Papermill. Xylanase pretreatment contained tow stages, the first stage was xylanase treatment, which was followed by alkaline extraction, the second stage. The xylanase could act on partial lignin and carbohydrate, chiefly xylan. The following alkaline extraction could dissolve something that could not be removed during the first stage. The result of pretreatment was to facilitate penetration of bleaching chemicals, to reduce effective chlorine consumption and to lower pollution loading of bleaching effluent. In the case of these two bleaching processes, the enzymatic pretreatment substantially enhanced the optical properties of the pulps. To calcium hypochlorite bleaching, strength properties of pulps wereimproved.

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

    Directory of Open Access Journals (Sweden)

    Dharm Dutt

    2010-08-01

    Full Text Available 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 comparison of properties AS-AQ pulping processes with soda and kraft pulping processes of H. cannabinus, C. sativa, and H. sabdariffa was made. All the properties were found to be better than soda and kraft pulps except tear index. All of the mechanical strength properties of handsheets of AS-AQ pulp improved except tear index. Therefore, the AS-AQ pulping process can be considered as ideal for manufacturing of paper grades like greaseproof, glassine, and high-quality writing and printing paper.

  10. 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

  11. Enzymatic hydrolysis of potato pulp

    OpenAIRE

    Mariusz Lesiecki; Wojciech Białas; Grażyna Lewandowicz

    2012-01-01

    Background. Potato pulp constitutes a complicated system of four types of polysaccharides: cellulose, hemicellulose, pectin and starch. Its composition makes it a potential and attractive raw material for the production of the second generation bioethanol. The aim of this research project was to assess the usefulness of commercial enzymatic preparations for the hydrolysis of potato pulp and to evaluate the effectiveness of hydrolysates obtained in this way as raw materials for ethanol ferment...

  12. 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.

  13. STRUCTURE AND PROPERTIES OF SOME NATURAL CELLULOSIC FIBRILS

    Directory of Open Access Journals (Sweden)

    Ramjee Subramanian

    2008-02-01

    Full Text Available This study examines the properties of cellulosic fibrillar fines manufactured from different pulp raw materials, bleached softwood kraft (bswk, themomechanical (TMP, and non-wood sisal. Chemical characterisation showed that the carbohydrate and lignin contents of sisal were between those of bswk and TMP. Sisal was found to contain about three times more calcium than bswk and TMP. Measurements from the immobilization kinetics showed that the solids content after immobilization was highest for the sisal suspension followed by TMP and bswk. This indicates that the dewatering ability of the fines suspension increases in the order bswkTMP>sisal. This is due to the highly fibrillated nature of bswk fines, as illustrated by fibre saturation point (FSP, differential scanning calorimetric (DSC, and hydrodynamic specific volume (HSV measurements.

  14. INVESTIGATION ON THE CAUSES OF EUCALYPTUS KRAFT PULP BRIGHTNESS REVERSION

    Directory of Open Access Journals (Sweden)

    Kátia M. M. Eiras

    2005-12-01

    Full Text Available Some high brightness eucalyptus Kraft pulps have shown poor brightness stability. In most cases, the causes have notbeen identified and permanent solutions have not been found. This work focused on evaluating the brightness stability profile of pulpsbleached by in sequences such as O(DC(PODD, O(DC(PODP, OD(PODD, OD(PODP, ODHT(PODD, ODHT(PODP, OA/D(PODD, OA/D(PODP, OAD(PODD and O(ZeD(PO. Brightness stability tests induced by according to Tappi UM200 procedureon samples bleached to 90±0.5% ISO. Brightness stability was measured after each bleaching stage of the various sequences andexpressed as brightness loss in % ISO. The results indicate that pulps bleached with sequences ending with a peroxide stage havehigher brightness stability compared to those ending with a chlorine dioxide stage. Pulps bleached with a standard sequence, initiatingwith a (DC stage, show brightness stability similar to that of pulp bleached by an ECF (Elementary chlorine free sequence initiatingwith a regular D0 stage. ECF sequences, initiated with hot stages produce pulps with higher brightness stability than sequencesinitiating with a regular D0 stage. The profile across the bleaching sequences shows a tendency of increased brightness stability inalkaline stages containing peroxide and decreased stability in those stages containing chlorine and/or chlorine dioxide, parallelingpulp carbonyl group content.

  15. ON THE RECOVERY OF HEMICELLULOSE BEFORE KRAFT PULPING

    Directory of Open Access Journals (Sweden)

    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.

  16. Influence of H2SO4 as Activator to ClO2 on the Bleaching Effects

    Directory of Open Access Journals (Sweden)

    Xingxiang Ji

    2012-08-01

    Full Text Available In this study, we show that chlorine dioxide activated by 4% Hydrochloric Acid Solution (HCl has the same bleaching effects as that by sulfuric acid (H2SO4. Chlorine dioxide is an important bleaching agent in ECF bleaching. Stable chlorine dioxide in conjunction with Hydrochloric Acid Solution (HCl activation in a certain proportion can be applied in the process of pulp bleach with a bleaching result of environment friendly, positive brightness stability, low pollutant bleach and pulp brightness stability, not easy to reverse. By experiment of OD, ODED, ODQP bleach Triploid of Populus Tomentos with stable chlorine dioxide activated by sulfuric acid (H2SO4. Moreover, the result of the experiment can prove that principle of activation of HCl to ClO2 is similar to H2SO4 to ClO2, that is, to provide an acid environment for ClO2.

  17. 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. PMID:27518034

  18. Isolation of Cellulose Nanofibers: Effect of Biotreatment on Hydrogen Bonding Network in Wood Fibers

    Directory of Open Access Journals (Sweden)

    Sreekumar Janardhnan

    2011-01-01

    Full Text Available The use of cellulose nanofibres as high-strength reinforcement in nano-biocomposites is very enthusiastically being explored due to their biodegradability, renewability, and high specific strength properties. Cellulose, through a regular network of inter- and intramolecular hydrogen bonds, is organized into perfect stereoregular configuration called microfibrils which further aggregate to different levels to form the fibre. Intermolecular hydrogen bonding at various levels, especially at the elementary level, is the major binding force that one need to overcome to reverse engineer these fibres into their microfibrillar level. This paper briefly describes a novel enzymatic fibre pretreatment developed to facilitate the isolation of cellulose microfibrils and explores effectiveness of biotreatment on the intermolecular and intramolecular hydrogen bonding in the fiber. Bleached Kraft Softwood Pulp was treated with a fungus (OS1 isolated from elm tree infected with Dutch elm disease. Cellulose microfibrils were isolated from these treated fibers by high-shear refining. The % yield of nanofibres and their diameter distribution (<50 nm isolated from the bio-treated fibers indicated a substantial increase compared to those isolated from untreated fibers. FT-IR spectral analysis indicated a reduction in the density of intermolecular and intramolecular hydrogen bonding within the fiber. X-ray spectrometry indicated a reduction in the crystallinity. Hydrogen bond-specific enzyme and its application in the isolation of new generation cellulose nano-fibers can be a huge leap forward in the field of nano-biocomposites.

  19. Bleach Plant Capital Reduction with Rapid DO Bleaching and Simplified (D/E/D) Stages

    Energy Technology Data Exchange (ETDEWEB)

    T. J. McDonough; C. E. Courchene; J-C. Baromes

    2000-08-01

    The objective of this work was to demonstrate the capabilities of a bleaching sequence that combined a short retention time initial chlorine dioxide stage, referred to as rapid D0, (D0R), with simplified bleaching stages, (D1/E/D2), that required only one final bleach washer. The test sequence DR(EPO)(D/E/D/) was compared to a control sequence, D(EPO)D, for both hardwood and softwood pulps. The capabilities of the DR(EPO)(D/E/D) sequence were successfully demonstrated. An existing three- or four-stage bleach plan can be converted to the more powerful DR(EPO)(D/E/D) sequence without the major capital cost of additional washers. The results from this study showed that the DR(EPO)(D/E/D) sequence can reach 85 brightness on SW with 2.8% total C1O2, while the control sequence, D(EPO)D, required 3.9% C1O2. There was a corresponding decrease in AOX for the test sequence. The strength of pulp bleached in the test sequence was similar to or slightly higher than the control. For the HW pu lp, the test sequence reached 88 brightness with 2.2% C1O2 compared to 3.3% C1O2 for the control. There was a corresponding decrease in AOX generation with the lower chemical requirements. The final viscosity and pulp strength for the test sequence on HW was significantly higher than the corresponding values for the control sequence.

  20. USE OF ALUMINUM TRIHYDRATE FILLER TO IMPROVE THE STRENGTH PROPERTIES OF CELLULOSIC PAPER EXPOSED TO HIGH TEMPERATURE TREATMENT

    Directory of Open Access Journals (Sweden)

    Hua Chen

    2011-05-01

    Full Text Available Cellulosic paper is thermolabile and its strength properties tend to decrease under high temperature conditions. In this work, the effects of aluminum trihydrate filler on the tensile and burst strength of paper prepared from bleached wood pulps were investigated. The use of aluminum trihydrate maintained the tensile and burst strength of paper sheet dried at 200 °C for 4 hours. Thermogravimetric analysis and differential scanning calorimetry gave the evidence that the maintainance of strength after drying associated with the use of aluminum trihydrate filler is possibly due to the increase in degradation temperature and heat absorption of cellulosic paper. The results regarding Fourier Transform Infrared spectroscopy, and the water retention value (WRV and crystallinity index of fibers indicated the alleviated degradation of fibers when aluminum trihydrate was incorporated into the paper matrix.

  1. 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.

  2. Evaluation of an experimental rat model for comparative studies of bleaching agents

    Directory of Open Access Journals (Sweden)

    Luciano Tavares Angelo Cintra

    2016-02-01

    Full Text Available ABSTRACT Dental materials, in general, are tested in different animal models prior to their clinical use in humans, except for bleaching agents. Objectives To evaluate an experimental rat model for comparative studies of bleaching agents by investigating the influence of different concentrations and application times of H2O2 gel in the pulp tissue during in-office bleaching of rats’ vital teeth. Material and methods The right and left maxillary molars of 50 Wistar rats were bleached with 20% and 35% H2O2 gels, respectively, for 5, 10, 15, 30, or 45 min (n=10 rats/group. Ten animals (control were untreated. The rats were killed after 2 or 30 days, and the maxillae were examined by light microscopy. Inflammation was evaluated by histomorphometric analysis with inflammatory cell counting in the coronal and radicular thirds of the pulp. The counting of fibroblasts was also performed. Scores were attributed to the odontoblastic layer and to vascular changes. The tertiary dentin area and the pulp chamber central area were histomorphometrically measured. Data were compared by the analysis of variance and the Kruskal-Wallis test (p<0.05. Results After 2 days, the amount of inflammatory cells increased in the occlusal third of the coronal pulp until the time of 15 min for both concentrations of bleaching gels. In 30 and 45 min groups of each concentration, the number of inflammatory cells decreased along with the appearance of necrotic areas. After 30 days, a reduction in the pulp chamber central area and an enlargement of tertiary dentin area were observed without the detection of inflammation areas. Conclusion The rat model of extra coronal bleaching showed to be adequate for bleaching protocols studies, as it was possible to observe alterations in the pulp tissues and in the tooth structure caused by different concentrations and periods of application of bleaching agents.

  3. Evaluation of an experimental rat model for comparative studies of bleaching agents

    Science.gov (United States)

    CINTRA, Luciano Tavares Angelo; BENETTI, Francine; FERREIRA, Luciana Louzada; RAHAL, Vanessa; ERVOLINO, Edilson; JACINTO, Rogério de Castilho; GOMES, João Eduardo; BRISO, André Luiz Fraga

    2016-01-01

    ABSTRACT Dental materials in general are tested in different animal models prior to the clinical use in humans, except for bleaching agents. Objectives To evaluate an experimental rat model for comparative studies of bleaching agents, by investigating the influence of different concentrations and application times of H2O2 gel in the pulp tissue during in-office bleaching of rats’ vital teeth. Material and Methods The right and left maxillary molars of 50 Wistar rats were bleached with 20% and 35% H2O2 gels, respectively, for 5, 10, 15, 30, or 45 min (n=10 rats/group). Ten animals were untreated (control). The rats were killed after 2 or 30 days, and the maxillae were examined by light microscopy. Inflammation was evaluated through histomorphometric analysis with inflammatory cell count in the coronal and radicular thirds of the pulp. Fibroblasts were also counted. Scores were attributed to odontoblastic layer and vascular changes. Tertiary dentin area and pulp chamber central area were measured histomorphometrically. Data were compared by analysis of variance and Kruskal-Wallis test (p<0.05). Results After 2 days, the amount of inflammatory cells increased in the coronal pulp occlusal third up to the 15-min application groups of each bleaching gel. In the groups exposed to each concentration for 30 and 45 min, the number of inflammatory cells decreased along with the appearance of necrotic areas. After 30 days, reduction on the pulp chamber central area and enlargement of the tertiary dentin area were observed, without the detection of inflammation areas. Conclusion The rat model of extracoronal bleaching showed to be adequate for studies of bleaching protocols, as it was possible to observe alterations in the pulp tissues and tooth structure caused by different concentrations and application periods of bleaching agents. PMID:27119766

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

    Directory of Open Access Journals (Sweden)

    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.

  5. Evaluation of bleachability on pine and eucalyptus kraft pulps

    Directory of Open Access Journals (Sweden)

    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. Tooth Whitening And Temperature Rise With Two Bleaching Activation Methods

    Science.gov (United States)

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

    2009-09-01

    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.

  7. ULTRASOUND-CATALYZED TEMPO-MEDIATED OXIDATION OF NATIVE CELLULOSE FOR THE PRODUCTION OF NANOCELLULOSE: EFFECT OF PROCESS VARIABLES

    Directory of Open Access Journals (Sweden)

    Shree Prakash Mishra

    2011-02-01

    Full Text Available In this study application of ultrasound in oxidizing native cellulose for the production of nanocellulose has been explored for the first time. Bleached hardwood kraft pulp was oxidized with an ultrasound (US catalyzed 2,2,6,6-tetramethylepiperidin-1-oxyl (TEMPO system (US-TEMPO-system at five different temperatures – 5, 15, 25, 35, and 45°C and two pH ranges, 8.5-9.0 and 10.0-10.5 – to obtain the optimum reaction conditions. The reaction pH and temperature have significant effect on the kinetics of the formation of carboxylate in the oxidized pulps and produce depolymerization at temperatures greater than 25°C. Formation of carboxylate on the cellulose chain is directly proportional to the NaBr concentration. The pulp oxidized by the US-TEMPO-system at 25°C had 10-15% more carboxyls and showed a ca. 10% increase in the nanocellulose yield when compared to the TEMPO-system without sono-catalysis.

  8. 木聚糖酶诱导释放负电荷及其对漂白硫酸盐浆纤维胶体作用和留着的影响%Xylanase-induced liberation of negatively charged species and their effect on colloidal interactions and the retention of bleached kraft pulp ifbers

    Institute of Scientific and Technical Information of China (English)

    苗成; 刘忠

    2016-01-01

    The ability and specificity of various monocomponent endo-1,4-β-xylanases to release negatively charged species from never-dried, bleached, birch kraft pulp was studied. The effects of dissolution of these xylan-based components on pulp ifltrate properties and the subsmoluent chemical retention were determined. The results revealed that the amount of charged species released depended on the xylanase and that the ratio of charged species released to dissolved xylan is not linear. Chemical retention tests showed that high levels of dissolved xylan interfere with the ifxation of colloidal species, which was conifrmed by removing the dissolved hemicelluloses. The roles of residual hemicellulose and the properties of modified fibers on chemical retention and the level of internal sizing are discussed.%本文研究未干燥的漂白硫酸盐浆中各种内切-1,4-β-木聚糖酶组分释放负电荷的能力和特异性,同时分析木聚糖组分溶解液对浆料滤液性能和化学留着的影响。实验结果表明,电荷释放的数量和木聚糖酶相关,溶解木聚糖的质量和电荷释放量不成线性关系。化学留着实验表明,高含量溶解木聚糖能够影响胶体的固化作用,因为该过程能够移除溶解的半纤维素。本文探究残留的半纤维素和改性纤维性能对化学留着的作用和浆内施胶的影响。

  9. Evaluation of temperature increase during in-office bleaching

    Directory of Open Access Journals (Sweden)

    Rafael Francisco Lia MONDELLI

    2016-04-01

    Full Text Available ABSTRACT The use of light sources in the bleaching process reduces the time required and promotes satisfactory results. However, these light sources can cause an increase in the pulp temperature. Objective The purpose of the present study was to measure the increase in intrapulpal temperature induced by different light-activated bleaching procedures with and without the use of a bleaching gel. Material and Methods A human maxillary central incisor was sectioned 2 mm below the cementoenamel junction. A K-type thermocouple probe was introduced into the pulp chamber. A 35% hydrogen peroxide bleaching gel was applied to the vestibular tooth surface. The light units used were a conventional halogen, a hybrid light (only LED and LED/Laser, a high intensity LED, and a green LED light. Temperature increase values were compared by two-way ANOVA and Tukey´s tests (p<0.05. Results There were statistically significant differences in temperature increases between the different light sources used and between the same light sources with and without the use of a bleaching gel. The presence of a bleaching gel generated an increase in intra-pulpal temperature in groups activated with halogen light, hybrid light, and high intensity LED. Compared to the other light sources, the conventional halogen lamp applied over the bleaching gel induced a significant increase in temperature (3.83±0.41°C. The green LED unit with and without gel application did not produce any significant intrapulpal temperature variations. Conclusion In the present study, the conventional halogen lamp caused the highest increase in intrapulpal temperature, and the green LED caused the least. There was an increase in temperature with all lights tested and the maximum temperature remained below the critical level (5.5°C. The addition of a bleaching gel led to a higher increase in intrapulpal temperatures.

  10. Evaluation of temperature increase during in-office bleaching

    Science.gov (United States)

    MONDELLI, Rafael Francisco Lia; SOARES, Ana Flávia; PANGRAZIO, Eugenio Gabriel Kegler; WANG, Linda; ISHIKIRIAMA, Sergio Kiyoshi; BOMBONATTI, Juliana Fraga Soares

    2016-01-01

    ABSTRACT The use of light sources in the bleaching process reduces the time required and promotes satisfactory results. However, these light sources can cause an increase in the pulp temperature. Objective The purpose of the present study was to measure the increase in intrapulpal temperature induced by different light-activated bleaching procedures with and without the use of a bleaching gel. Material and Methods A human maxillary central incisor was sectioned 2 mm below the cementoenamel junction. A K-type thermocouple probe was introduced into the pulp chamber. A 35% hydrogen peroxide bleaching gel was applied to the vestibular tooth surface. The light units used were a conventional halogen, a hybrid light (only LED and LED/Laser), a high intensity LED, and a green LED light. Temperature increase values were compared by two-way ANOVA and Tukey´s tests (p<0.05). Results There were statistically significant differences in temperature increases between the different light sources used and between the same light sources with and without the use of a bleaching gel. The presence of a bleaching gel generated an increase in intra-pulpal temperature in groups activated with halogen light, hybrid light, and high intensity LED. Compared to the other light sources, the conventional halogen lamp applied over the bleaching gel induced a significant increase in temperature (3.83±0.41°C). The green LED unit with and without gel application did not produce any significant intrapulpal temperature variations. Conclusion In the present study, the conventional halogen lamp caused the highest increase in intrapulpal temperature, and the green LED caused the least. There was an increase in temperature with all lights tested and the maximum temperature remained below the critical level (5.5°C). The addition of a bleaching gel led to a higher increase in intrapulpal temperatures. PMID:27119761

  11. Carboxymethyl Cellulose (CMC) from Oil Palm Empty Fruit Bunch (OPEFB) in the new solvent Dimethyl Sulfoxide (DMSO)/Tetrabutylammonium Fluoride (TBAF)

    Science.gov (United States)

    Eliza, M. Y.; Shahruddin, M.; Noormaziah, J.; Rosli, W. D. Wan

    2015-06-01

    The surplus of Oil Palm is the most galore wastes in Malaysia because it produced about half of the world palm oil production, which contributes a major disposal problem Synthesis from an empty fruit bunch produced products such as Carboxymethyl Cellulose (CMC), could apply in diverse application such as for paper coating, food packaging and most recently, the potential as biomaterials has been revealed. In this study, CMC was prepared by firstly dissolved the bleached pulp from OPEFB in mixture solution of dimethyl sulfoxide(DMSO)/tetrabutylammonium fluoride (TBAF) without any prior chemical modification. It took only 30 minutes to fully dissolve at temperature 60°C before sodium hydroxide (NaOH) were added for activation and monochloroacetateas terrifying agent. The final product is appeared in white powder, which is then will be analyzedby FTIR analysis. FTIR results show peaks appeared at wavenumber between 1609 cm-1 to 1614 cm-1 proved the existence of carboxymethyl groups which substitute OH groups at anhydroglucose(AGU) unit. As a conclusion, mixture solution of DMSO/TBAF is the suitable solvent used for dissolved cellulose before modifying it into CMC with higher Degree of Substitution (DS). Furthermore, the dissolution of the OPEFB bleached pulp was easy, simple and at a faster rate without prior chemical modification at temperature as low as 60°C.

  12. Degradation of cellulose in irradiated wood and purified celluloses

    International Nuclear Information System (INIS)

    The degradation of cellulose chains in Pinus radiata and Eucalyptus regnans given small gamma-radiation doses has been studied. Scission yields showed marked dose-dependency effects, of which some appear to be due to an inherent dose-dependency exhibited by cellulose itself, and others indicate a protective action of some natural wood constituents. A uniform treatment of viscometry data reported by various workers who have studied radiation-induced degradation of purified cellulose materials, has been used to enable their scission results to be compared with each other and with those for natural wood cellulose of various dose levels. Generally, cellulose in wood is less degraded by radiation than is purified cellulose. However, with Eucalyptus regnans remarkably high scission yields, significantly higher than expected for purified cellulose, were observed at dose levels of 0.5-1.0 x 104Gy. The relevance of these results to changes in pulp yield following irradiation of wood chips, is briefly discussed. (author)

  13. CFD-Based Investigation into Flow Field of S-Type Discharger at the Bottom of High-Consistency Pulp-Bleaching Tower%基于CFD的高浓漂白塔塔底S型卸料器的流场研究

    Institute of Scientific and Technical Information of China (English)

    曾劲松; 陈克复; 李军; 徐峻

    2011-01-01

    采用Fluent软件的欧拉粒子多相流模型、κ-ε湍流方程结合滑移网格运算法则(SG),在分析稀纸浆的绝对压力云图、水的速度矢量图、纸浆纤维的体积分数的基础上,对高浓纸浆漂白塔塔底卸料系统的S型卸料器及其稀释区的流动特性进行了瞬态模拟.结果表明:该卸料器的几何形状有利于卸料,而且卸料均匀、彻底;转速、黏度、密度、颗粒直径对卸料效果都有影响,其中转速的影响最大;水的切向、径向、轴向速度分量与粒子图像速度仪(PIV)测量的数据相吻合,说明欧拉粒子多相流模型和SG技巧组合起来能够很好地描述和研究S型卸料器及其稀释区的流场.%Based on the standard k-ε turbulence model in combination with both the granular Eulerian multiphase model and the sliding-grid (SG) technology in Fluent, the contour of absolute pressure, the vectors of water velocity and the volume fraction of pulp fibers were analyzed, and the instantaneous flow behaviors of the pulp in the dilution zone and the S-type discharger at the bottom of high-consistency pulp-bleaching tower were simulated. The results show that the discharger helps to achieve uniform and complete discharge due to its special shape, that the rotating speed, the viscosity, the density and the particle diameter all influence the discharging effect, especially the rotating speed, and that the simulated tangential, radial and axial velocities of water accord well with the data measured using a particle image velometer (PIV), which means that the combination of granular Eulerian multiphase model and SG technology is effective in describing the flow fields in the discharger and its dilution zone.

  14. The Effect of Mechanochemical Treatment of the Cellulose on Characteristics of Nanocellulose Films.

    Science.gov (United States)

    Barbash, V A; Yaschenko, O V; Alushkin, S V; Kondratyuk, A S; Posudievsky, O Y; Koshechko, V G

    2016-12-01

    The development of the nanomaterials with the advanced functional characteristics is a challenging task because of the growing demand in the market of the optoelectronic devices, biodegradable plastics, and materials for energy saving and energy storage. Nanocellulose is comprised of the nanosized cellulose particles, properties of which depend on characteristics of plant raw materials as well as methods of nanocellulose preparation. In this study, the effect of the mechanochemical treatment of bleached softwood sulfate pulp on the optical and mechanical properties of nanocellulose films was assessed. It was established that the method of the subsequent grinding, acid hydrolysis and ultrasound treatment of cellulose generated films with the significant transparency in the visible spectral range (up to 78 % at 600 nm), high Young's modulus (up to 8.8 GPa), and tensile strength (up to 88 MPa) with increased ordering of the packing of the cellulose macromolecules. Morphological characterization was done using the dynamic light scattering (DLS) analyzer and transmission electron microscopy (TEM). The nanocellulose particles had an average diameter of 15-30 nm and a high aspect ratio in the range 120-150. The crystallinity was increased with successive treatments as shown by the X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analysis. The thermal degradation behavior of cellulose samples was explored by thermal gravimetric analysis (TGA). PMID:27644236

  15. The Effect of Mechanochemical Treatment of the Cellulose on Characteristics of Nanocellulose Films

    Science.gov (United States)

    Barbash, V. A.; Yaschenko, O. V.; Alushkin, S. V.; Kondratyuk, A. S.; Posudievsky, O. Y.; Koshechko, V. G.

    2016-09-01

    The development of the nanomaterials with the advanced functional characteristics is a challenging task because of the growing demand in the market of the optoelectronic devices, biodegradable plastics, and materials for energy saving and energy storage. Nanocellulose is comprised of the nanosized cellulose particles, properties of which depend on characteristics of plant raw materials as well as methods of nanocellulose preparation. In this study, the effect of the mechanochemical treatment of bleached softwood sulfate pulp on the optical and mechanical properties of nanocellulose films was assessed. It was established that the method of the subsequent grinding, acid hydrolysis and ultrasound treatment of cellulose generated films with the significant transparency in the visible spectral range (up to 78 % at 600 nm), high Young's modulus (up to 8.8 GPa), and tensile strength (up to 88 MPa) with increased ordering of the packing of the cellulose macromolecules. Morphological characterization was done using the dynamic light scattering (DLS) analyzer and transmission electron microscopy (TEM). The nanocellulose particles had an average diameter of 15-30 nm and a high aspect ratio in the range 120-150. The crystallinity was increased with successive treatments as shown by the X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analysis. The thermal degradation behavior of cellulose samples was explored by thermal gravimetric analysis (TGA).

  16. TARGETED DISRUPTION OF HYDROXYL CHEMISTRY AND CRYSTALLINITY IN NATURAL FIBERS FOR THE ISOLATION OF CELLULOSE NANO-FIBERS VIA ENZYMATIC TREATMENT

    Directory of Open Access Journals (Sweden)

    Sreekumar Janardhnan

    2011-04-01

    Full Text Available Cellulose is the Earth’s most abundant biopolymer. Exploiting its environmentally friendly attributes such as biodegradability, renewability, and high specific strength properties are limited by our inability to isolate them from the secondary cell wall in an economical manner. Intermolecular and intramolecular hydrogen bonding between the cellulose chains is the major force one needs to overcome in order to isolate the cellulose chain in its microfibrillar form. This paper describes how a hydrogen bond-specific enzyme disrupts the crystallinity of the cellulose, bringing about internal defibrillation within the cell wall. Bleached kraft softwood pulp was treated with a fungus (OS1 isolated from an elm tree infected with Dutch elm disease. FT-IR spectral analysis indicated a significant reduction in the density of intermolecular and intramolecular hydrogen bonding within the fiber. X-ray spectrometry indicated a reduction in the crystallinity. The isolated nano-cellulose fibers also exhibited better mechanical strength compared to those isolated through conventional methods. The structural disorder created in the crystalline region in the plant cell wall by hydrogen bond-specific enzymes is a key step forward in the isolation of cellulose at its microfibrillar level.

  17. ALKALINE PEROXIDE BLEACHING OF HOT WATER TREATED WHEAT STRAW

    Directory of Open Access Journals (Sweden)

    Suvi Mustajoki

    2010-05-01

    Full Text Available The aim of this study was to evaluate the possibilities for chemical consumption reduction in P-P-Paa-P bleaching (P alkaline peroxide stage, Paa peracetic stage of hot water treated straw and the effect of the wheat straw variability on the process. Papermaking fibre production from wheat straw using such a process could be implemented on a small scale if chemical consumption was low enough to eliminate the need for chemical recovery. The pulp properties obtained with this process are equal to or even superior to the properties of wheat straw soda pulp. The possibility of enhancing the first peroxide stage with oxygen and pressure was studied. The possibility for substitution of sodium hydroxide partially with sodium carbonate was also investigated. The objective was to achieve International Standardization Organization (ISO brightness of 75%, with minimal sodium hydroxide consumption, whilst maintaining the pulp properties. The optimization of the peroxide bleaching is challenging if the final brightness target cannot be reduced. Results indicate that up to 25% of the sodium hydroxide could be substituted with sodium carbonate without losing brightness or affecting pulp properties. Another possibility is a mild alkali treatment between the hot water treatment and the bleaching sequence.

  18. Exploring biosensor applications with cotton cellulose nanocrystalline protein and peptide conjugates

    Science.gov (United States)

    Sensor I: Nano-crystalline preparations were produced through acid hydrolysis and mechanical breakage of the cotton fibers from a scoured and bleached cotton fabric and a scoured and bleached, mercerized fabric, which was shown to produce cellulose I (NCI) and cellulose II (NCII) crystals respective...

  19. Production of pulp from Salix viminalis energy crops using the FIRSST process.

    Science.gov (United States)

    Lavoie, Jean-Michel; Capek-Menard, Eva; Gauvin, Henri; Chornet, Esteban

    2010-07-01

    In this work, isolation of the cellulose fibres was carried out via the Feedstock Impregnation Rapid and Sequential Steam Treatment process (FIRSST). The latter allows the separation of extractives, hemicellulosic sugars and lignin isolating the cellulose fibres. Quantitative data on the constitutive macromolecules of biomass was obtained using ASTM or TAPPI standard methods. Carbohydrates found in the hemicelluloses were also quantified using HPLC. Kraft pulp from whole biomass has also been produced at a bench scale (few kg per batch) using known and established pulping conditions. The pulps from both pulping techniques were tested following ATTPC standard methods. Pulp yields were of 34% for the classical Kraft processes (using whole biomass) while the FIRSST process showed yields around 30%. The average fibre lengths were similar for FIRSST pulp (0.39 mm) and Kraft pulp (0.41 mm) and the mechanical properties of the FIRSST pulp were as good as those of the Kraft pulp.

  20. Cellulose microfibril-water interaction as characterized by isothermal thermogravimetric analysis and scanning electron microscopy

    Directory of Open Access Journals (Sweden)

    Suman K. Sen

    2012-11-01

    Full Text Available Microfibrillated celluloses, liberated from macroscopic lignocellulosic fibers by mechanical means, are sub-fiber elements with lengths in the micron scale and diameters ranging from 10 to a few hundred nanometers. These materials have shown strong water interactions. This article describes an investigation and quantification of the ‘hard-to-remove (HR water content’ in cellulose fibers and microfibrillated structures prepared from fully bleached softwood pulp (BSW. The fiber/fibril structure was altered by using an extended beating process (up to 300 minutes, and water interactions were determined with isothermal thermogravimetric analysis (TGA. Isothermal TGA is shown to be a convenient and insightful characterization method for fiber-water interactions for fibers and microfibrils at small sample size. In addition, scanning electron microscopic (SEM images depict the differences between fibers and microfibrils with respect to beating time in the dried consolidated structures. Highly refined pulps with microfibrils were determined to have two critical drying points, i.e., two minima in the second derivative of weight versus time, not before reported in the literature. Also in this study, hard-to-remove (HR water content is related to the area above the first derivative curve in the constant rate and falling rate drying zones. This measure of HR water correlates with a previous measurement method of HR water but is less ambiguous for materials that lack a constant drying rate zone. Blends of unbeaten fibers and microfibril containing samples were prepared and show potential as composite materials.

  1. ON THE RECOVERY OF HEMICELLULOSE BEFORE KRAFT PULPING

    OpenAIRE

    Carlos Vila; Javier Romero; José Luis Francisco,; Valentín Santos,; Juan Carlos Parajó

    2012-01-01

    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 pressurize...

  2. Enzymatic hydrolysis of potato pulp

    Directory of Open Access Journals (Sweden)

    Mariusz Lesiecki

    2012-03-01

    Full Text Available Background. Potato pulp constitutes a complicated system of four types of polysaccharides: cellulose, hemicellulose, pectin and starch. Its composition makes it a potential and attractive raw material for the production of the second generation bioethanol. The aim of this research project was to assess the usefulness of commercial enzymatic preparations for the hydrolysis of potato pulp and to evaluate the effectiveness of hydrolysates obtained in this way as raw materials for ethanol fermentation. Material  and methods. Sterilised potato pulp was subjected to hydrolysis with commercial enzymatic preparations. The effectiveness of the preparations declared as active towards only one fraction of potato pulp (separate amylase, pectinase and cellulase activity and mixtures of these preparations was analysed. The monomers content in hydrolysates was determined using HPLC method. Results.  The application of amylolytic enzymes for potato pulp hydrolysis resulted in the release of only 18% of raw material with glucose as the dominant (77% constituent of the formed product. In addition, 16% galactose was also determined in it. The hydrolysis of the cellulose fraction yielded up to 35% raw material and the main constituents of the obtained hydrolysate were glucose (46% and arabinose (40%. Simultaneous application of amylolytic, cellulolytic and pectinolytic enzymes turned out to be the most effective way of carrying out the process as its efficiency in this case reached 90%. The obtained hydrolysate contained 63% glucose, 25% arabinose and 12% other simple substances. Conclusion. The application of commercial enzymatic preparations made it possible to perform potato pulp hydrolysis with 90% effectiveness. This was achieved by the application of a complex of amylolytic, cellulolytic and pectinolytic enzymes and the hydrolysate obtained in this way contained, primarily, glucose making it a viable substrate for ethanol fermentation.

  3. A NEW PULP YIELD PREDICTION METHOD APPLIED TO KRAFT,KRAFT-AQ,POLYSULFIDE AND PSAQ PULPING OF ROCK MAPLE

    Institute of Scientific and Technical Information of China (English)

    Adriaan van Heiningen; Yang Gao; Mehmet Sefik Tunc

    2004-01-01

    Pulp yield has a major impact on the competitiveness of a mill. In order to optimize pulp yield, for example by changing operating conditions, a mill must be able to monitor the yield accurately. In our previous work,a new method was presented for prediction of pulp yield. The method is based on a fundamental relationship derived from the kinetics of the alkaline hydrolysis, peeling and stopping reactions of cellulose and the cellulose mass balance during pulping. In this paper the application of the pulp yield prediction equation for pulping of Rock Maple is investigated. The effect of different operating conditions, such as H-factor, temperature, alkali charge, sulfidity, and the presence of anthraquinone and polysulfide are described.

  4. A NEW PULP YIELD PREDICTION METHOD APPLIED TO KRAFT, KRAFT-AQ, POLYSULFIDE AND PSAQ PULPING OF ROCK MAPLE

    Institute of Scientific and Technical Information of China (English)

    AdriaanvanHeiningen; YangGao; MehmetSefikTunc

    2004-01-01

    Pulp yield has a major impact on the competitiveness of a mill. In order to optimize pulp yield, for example by changing operating conditions, a mill must be able to monitor the yield accurately. In our previous work, a new method was presented for prediction of pulp yield. The method is based on a fundamental relationship derived from the kinetics of the alkaline hydrolysis, peeling and stopping reactions of cellulose and the cellulose mass balance during pulping. In this paper the application of the pulp yield prediction equation for pulping of Rock Maple is investigated. The effect of different operating conditions, such as H-factor, temperature, alkali charge, sulfidity, and the presence of anthraquinone and polysulfide are described.

  5. 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.

  6. Strong and electrically conductive nanopaper from cellulose nanofibers and polypyrrole.

    Science.gov (United States)

    Lay, Makara; Méndez, J Alberto; Delgado-Aguilar, Marc; Bun, Kim Ngun; Vilaseca, Fabiola

    2016-11-01

    In this work, we prepare cellulose nanopapers of high mechanical performance and with the electrical conductivity of a semiconductor. Cellulose nanofibers (CNF) from bleached softwood pulp were coated with polypyrrole (PPy) via in situ chemical polymerization, in presence of iron chloride (III) as oxidant agent. The structure and morphology of nanopapers were studied, as well as their thermal, mechanical and conductive properties. Nanopaper from pure CNF exhibited a very high tensile response (224MPa tensile strength and 14.5GPa elastic modulus). The addition of up to maximum 20% of polypyrrole gave CNF/PPy nanopapers of high flexibility and still good mechanical properties (94MPa strength and 8.8GPa modulus). The electrical conductivity of the resulting CNF/PPy nanopaper was of 5.2 10(-2)Scm(-1), with a specific capacitance of 7.4Fg(-1). The final materials are strong and conductive nanopapers that can find application as biodegradable flexible thin-film transistor (TFT) or as flexible biosensor. PMID:27516283

  7. Evaluation of an experimental rat model for comparative studies of bleaching agents.

    Science.gov (United States)

    Cintra, Luciano Tavares Angelo; Benetti, Francine; Ferreira, Luciana Louzada; Rahal, Vanessa; Ervolino, Edilson; Jacinto, Rogério de Castilho; Gomes Filho, João Eduardo; Briso, André Luiz Fraga

    2016-04-01

    Dental materials in general are tested in different animal models prior to the clinical use in humans, except for bleaching agents. Objectives To evaluate an experimental rat model for comparative studies of bleaching agents, by investigating the influence of different concentrations and application times of H2O2 gel in the pulp tissue during in-office bleaching of rats' vital teeth. Material and Methods The right and left maxillary molars of 50 Wistar rats were bleached with 20% and 35% H2O2 gels, respectively, for 5, 10, 15, 30, or 45 min (n=10 rats/group). Ten animals were untreated (control). The rats were killed after 2 or 30 days, and the maxillae were examined by light microscopy. Inflammation was evaluated through histomorphometric analysis with inflammatory cell count in the coronal and radicular thirds of the pulp. Fibroblasts were also counted. Scores were attributed to odontoblastic layer and vascular changes. Tertiary dentin area and pulp chamber central area were measured histomorphometrically. Data were compared by analysis of variance and Kruskal-Wallis test (pbleaching gel. In the groups exposed to each concentration for 30 and 45 min, the number of inflammatory cells decreased along with the appearance of necrotic areas. After 30 days, reduction on the pulp chamber central area and enlargement of the tertiary dentin area were observed, without the detection of inflammation areas. Conclusion The rat model of extracoronal bleaching showed to be adequate for studies of bleaching protocols, as it was possible to observe alterations in the pulp tissues and tooth structure caused by different concentrations and application periods of bleaching agents. PMID:27119766

  8. ON THE BLACK LIQUOR AND RECYCLE COOKING OF AS-AQ STRAW PULP

    Institute of Scientific and Technical Information of China (English)

    Haiqiang Shi; Beihai He; Bingyue Liu

    2004-01-01

    Thick black liquor, thin black liquor and solid state sodium hydroxide are added to the liquor treated by sulfur dioxide, then the blended liquor is used to recycle cooking of straw pulp. The black liquor,separated liquor and pulp of every cycles are analyzed respectively. Result shows that the content of lignin and organism in recycle black liquor and separated liquor increases faster in the first three cycles and then continues to increase slowly till four or five times, after that it trends to a stable state. The main organism separated from waste liquor of AS-AQ treated by sulfur dioxide is alkali-lignin,above 50% of total lignin in black liquor. The yield of pulp made from recycle cooking is steady, the hardness of pulp has a great improvement with recycle cooking. The brightness of pulp reduces correspondingly before bleaching, and after bleaching the brightness of pulp is relatively high and steady at the same sodium hypo chlorite dosage.

  9. Bleach vs. Bacteria

    Science.gov (United States)

    ... Articles | Inside Life Science Home Page Bleach vs. Bacteria By Sharon Reynolds Posted April 2, 2014 Your ... hypochlorous acid to help kill invading microbes, including bacteria. Researchers funded by the National Institutes of Health ...

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

    OpenAIRE

    Costa, M. M.; Colodette, J.L.

    2007-01-01

    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 oxy...

  11. Avaliação do emprego de microfiltração para remoção de fibras do efluente de branqueamento de polpa celulósica Evaluation of the use of microfiltration for removal of fiber from bleaching pulp mill effluent

    Directory of Open Access Journals (Sweden)

    Míriam Cristina Santos Amaral

    2013-03-01

    Full Text Available O processo de branqueamento é o estágio em que ocorre a maior perda de fibras durante a fabricação de polpa celulósica. Além de ser uma perda de produto, estas fibras aumentam a concentração de matéria orgânica do efluente dificultando seu tratamento. O objetivo deste trabalho foi avaliar o emprego de microfiltração (MF na remoção de fibras de efluente de branqueamento alcalino de polpa celulósica. Foi empregada membrana de poli(éter imida com tamanho médio de poros de 0,5 µm e área de filtração de 0,05 m². O efeito das condições operacionais no fluxo permeado foi avaliado através do monitoramento do perfil de fluxo durante a operação em diferentes condições de velocidade de escoamento (Reynolds de 1.226, 1.653 e 2.043, pH da alimentação (7, 10 e 10,6, temperatura (28, 43 e 48°C e pressão de operação através da avaliação da pressão crítica. Os resultados mostraram que a MF é um processo eficiente para remoção de fibras, apresentado 99% eficiência de remoção de sólidos suspensos. O melhor desempenho da operação de MF foi obtido empregando pH 7, pressão de 1 bar e Re de 1.653. Os resultados mostram que a redução do fluxo se deve principalmente à formação de torta.The bleaching process is the stage where there is the greatest loss of fibers during the pulp production. Besides being a waste of product, these fibers increase the concentration of organic matter in the effluent and make the treatment of effluent more difficult. The aim of this study was to evaluate the use of microfiltration (MF in the removal of fiber of effluent of alkaline bleaching pulp mill. The membrane employed was hollow fiber poly (ether imide, with average pore size of 0.5 µm and filtration area of 0.05 m². The effect of operating conditions on the permeate flux was evaluated by monitoring the flux profile during operation in different conditions of flow velocity (Reynolds 1,226, 1,653 and 2,043, pH of feeding (7, 10

  12. Intracoronal bleaching of discolored non-vital teeth using laser irradiation: a case report

    Science.gov (United States)

    Marchesan, Melissa A.; de Castro, Fabiana C.; Matarazzo, Alexandre T.; Pecora, Jesus D.; Zanin, Fatima A.; Brugnera, Aldo, Jr.

    2004-09-01

    Dissemination of blood into the dentinal tubules caused by pulp extirpation or traumatically induced internal pulp bleeding is a possible cause of discoloration of non-vital teeth. Discolored teeth, especially in the anterior region, can result in considerable cosmetic impairment. The whitening of these teeth is an alternative therapeutic method that is relatively non-invasive and conserves dental hard tissue. Recently, intracoronal bleaching of pulpless discolored teeth can be performed with the association of laser irradiation to hydrogen and carbamide peroxide and can even be accomplished in one session. This report shows a clinical case of an endodontically treated tooth submitted to bleaching using LED light and infrared LLLT therapy.

  13. 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)

  14. Solubility Behaviour of Cellulose in a Sodium Hydrate/Urea/Thiourea Aqueous Solvent

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shuai; CHENG Feng-wei; LI Fa-xue; YU Jian-yong; GU Li-xia

    2008-01-01

    Cellulose pulps were directly dissolved in a green solvent of sodium hydrate/urea/thiourea/water with different composition for the purpose to prepare new regenerated cellulose fibers or films. The results showed that the highest solubility of cellulose in the solvent with the composition of 8/8/6.5/77.5. The results revealed that the pulp feeding sequence, stirring rate, pre-treatment of pulp and pulp size affected the cellulose concentration in the green solvent. Accordingly, the more effective dissolution method was proposed in order to get higher concentration of cellulose. Furthermore, the properties of solution prepared by different kinds of pulps in the solvent were investigated by ARES rheometer. Rheological analyses indicated that all cellulose aqueous solutions in their high concentration were pseudoplastic fluids and sensitive to temperature and tended to transform to gel when temperature increased.

  15. 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.

  16. Laser cleaning of particulates from paper: Comparison between sized ground wood cellulose and pure cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Arif, S.; Kautek, W., E-mail: wolfgang.kautek@univie.ac.at

    2013-07-01

    Visible laser cleaning of charcoal particulates from yellow acid mechanical ground wood cellulose paper was compared with that from bleached sulphite softwood cellulose paper. About one order of magnitude of fluence range is available for a cleaning dynamics between the cleaning threshold and the destruction threshold for two laser pulses. Wood cellulose paper exhibited a higher destruction threshold of the original paper than that of the contaminated specimen because of heat transfer from the hot or evaporating charcoal particulates. In contrast, the contaminated bleached cellulose paper exhibited a higher destruction threshold due to shading by the particulates. The graphite particles are not only detached thermo-mechanically, but also by evaporation or combustion. A cleaning effect was found also outside the illuminated areas due to lateral blasting. Infrared measurements revealed dehydration/dehydrogenation reactions and cross-links by ether bonds together with structural changes of the cellulose chain arrangement and the degree of crystallinity.

  17. Carbohydrate components and crystalline structure of organosolv hemp (Cannabis sativa L.) bast fibers pulp.

    Science.gov (United States)

    Gümüşkaya, Esat; Usta, Mustafa; Balaban, Mualla

    2007-02-01

    Changes in carbohydrate components and crystalline structure of hemp bast fibers during organosolv pulping were investigated by X-ray diffractometry, FT-IR spectroscopy and high performance liquid chromatography (HPLC). The reasons for defibrillation and beating problems with organosolv hemp bast fiber pulp were investigated with reference to these properties of pulp samples. Hemp bast fibers and organosolv pulp samples had low hemicellulose contents and high cellulose contents. It was found that the disorder parameter of cellulose in hemp bast fibers was very low, when crystalline cellulose ratio was high and the crystalline structure of cellulose in hemp bast fibers was very stable. These properties affected defibrillation and beating of organosolv hemp bast fibers pulp negatively.

  18. Biocomposite cellulose-alginate films: promising packaging materials.

    Science.gov (United States)

    Sirviö, Juho Antti; Kolehmainen, Aleksi; Liimatainen, Henrikki; Niinimäki, Jouko; Hormi, Osmo E O

    2014-05-15

    Biocomposite films based on cellulose and alginate were produced using unmodified birch pulp, microfibrillated cellulose (MFC), nanofibrillated cellulose (NFC) and birch pulp derivate, nanofibrillated anionic dicarboxylic acid cellulose (DCC), having widths of fibres ranging from 19.0 μm to 25 nm as cellulose fibre materials. Ionically cross-linked biocomposites were produced using Ca(2+) cross-linking. Addition of micro- and nanocelluloses as a reinforcement increased the mechanical properties of the alginate films remarkably, e.g. addition of 15% of NFC increased a tensile strength of the film from 70.02 to 97.97 MPa. After ionic cross-linking, the tensile strength of the film containing 10% of DCC was increased from 69.63 to 125.31 MPa. The biocomposite films showed excellent grease barrier properties and reduced water vapour permeability (WVP) after the addition of cellulose fibres, except when unmodified birch pulp was used. PMID:24423542

  19. Pulping and paper properties of Palmyra palm fruit fibers

    Directory of Open Access Journals (Sweden)

    Waranyou Sridach

    2010-05-01

    Full Text Available Palmyra palm fruit fibers have the properties to be used as an alternative raw material of cellulosic pulps for papermaking.Acid and alkali pulping were investigated by using nitric acid and caustic soda on a laboratory scale, with the purpose of producing printing or writing grade pulp. The chemical composition of fiber strands from palmyra palm fruits were examined, such as holocellulose, cellulose, pentosan, lignin and extractives. The yields of acid and soda pulps were below 40%. The main physical and mechanical properties of hand sheets produced from acid and soda processes were evaluated on 80 g/m2 test sheets as functions of the following parameters: tensile index, tear index, and brightness. The mechanical properties of soda pulps were developed by twin-roll press while it was not necessary to fibrillate acidic pulps through the beating step. The soda pulp sheets presented a lower brightness than that of acidic pulp sheets. The mechanicaland physical properties of the acidic and alkaline pulps verified that they were of an acceptable quality for papermaking.

  20. Bleach Neutralizes Mold Allergens

    Science.gov (United States)

    Science Teacher, 2005

    2005-01-01

    Researchers at National Jewish Medical and Research Center have demonstrated that dilute bleach not only kills common household mold, but may also neutralize the mold allergens that cause most mold-related health complaints. The study, published in the Journal of Allergy and Clinical Immunology, is the first to test the effect on allergic…

  1. Influence of enzyme and chemical adsorption on the thermal degradation path for eucalyptus pulp

    International Nuclear Information System (INIS)

    Highlights: ► Enzymes and chemicals adsorption changes thermal degradation path of cellulose. ► Adsorptions on pulp fibres increase their amorphous cellulose content. ► Charring/volatilization ratio of pulp is affected by adsorptions. - Abstract: Changes in thermal degradation path of eucalyptus pulp support enzymes (laccase from Trametes villosa) and chemicals (Tris–HCl or tartrate–tartaric buffer) adsorption on cellulose during biobleaching, thereby increasing cellulose amount that degrades at low temperature and decreasing the apparent crystallinity (ApC) of cellulose crystallites. Changes in ApC, which can be assessed by thermogravimetric analysis —but not X-ray diffraction spectroscopy—affect cellulose volatilization; thus, the higher ApC is, the lower is char production and the higher the volatilization temperature. A linear relationship between ApC and the volatilization/charring ratio (V/C) was observed in this work.

  2. SIMULTANEOUS DETERMINATION OF CHLORINE DIOXIDE AND HYPOCHLOROUS ACID IN BLEACHING SYSTEM

    Directory of Open Access Journals (Sweden)

    Qiang Wang

    2011-04-01

    Full Text Available This study has demonstrated a rapid spectroscopic method for the determination of chlorine dioxide and hypochlorous acid concentrations in the pulp bleaching processes. It was found that chlorine dioxide and hypochlorous acid have an isosbestic wavelength of 295 nm. The soluble lignin in such a system is the main interference, but can be corrected by determining the absorbances at 295 nm, 380 nm, and 480 nm. Thus, based on the spectroscopic measurements at 295 nm (the isosbestic point wavelength for chlorine dioxide and hypochlorous acid, 380 nm (absorbance wavelength of chlorine dioxide and 480 nm (the acid soluble lignin absorbance wavelength, the chlorine dioxide and hypochlorous acid concentrations in the bleaching process can be quantified. However, hypochlorous acid was not detected in the real bleaching effluent for its low content. The present method is simple, rapid, accurate, and has the potential for on-line monitoring of the chlorine dioxide bleaching process.

  3. Physical properties and morphology of films prepared from microfibrillated cellulose and microfibrillated cellulose in combination with amylopectin

    DEFF Research Database (Denmark)

    Plackett, David; Anturi, Harvey; Hedenqvist, Mikael;

    2010-01-01

    Two types of microfibrillated cellulose (MFC) were prepared using either a sulfite pulp containing a high amount of hemicellulose (MFC 1) or a carboxymethylated dissolving pulp (MFC 2). MFC gels were then combined with amylopectin solutions to produce solvent-cast MFC-reinforced amylopectin films...

  4. Novel Pulping Technology: Directed Green Liquor Utilization (D-GLU) Pulping

    Energy Technology Data Exchange (ETDEWEB)

    Lucian A. Lucia

    2005-11-15

    The general objectives of this new project are the same as those described in the original proposal. Conventional kraft pulping technologies will be modified for significant improvements in pulp production, such as strength, bleachability, and yield by using green liquor, a naturally high, kraft mill-derived sulfidity source. Although split white liquor sulfidity and other high sulfidity procedures have the promise of addressing several of the latter important economic needs of pulp mills, they require considerable engineering/capital retrofits, redesigned production methods, and thus add to overall mill expenditures. Green liquor use, however, possesses the required high sulfidity to obtain in general the benefits attributable to higher sulfidity cooking, without the required capital constraints for implementation. Before introduction of green liquor in our industrial operations, a stronger understanding of its fundamental chemical interaction with the lignin and carbohydrates in US hardwood and softwoods must be obtained. In addition, its effect on bleachability, enhancement of pulp properties, and influence on the overall energy and recovery of the mill requires further exploration before the process witnesses widespread mill use in North America. Thus, proof of principle will be accomplished in this work and the consequent effect of green liquor and other high sulfide sources on the pulping and bleaching operations will be explored for US kraft mills. The first year of this project will generate the pertinent information to validate its ability for implementation in US pulping operations, whereas year two will continue this work while proceeding to analyze pulp bleachability and final pulp/paper properties and develop a general economic and feasibility analysis for its eventual implementation in North America.

  5. Bleaching of Black Human Hair

    Institute of Scientific and Technical Information of China (English)

    林琳

    2001-01-01

    Bleaching of black human hair has been studied systematically. On the basis of experimental data the technology of human hair bleaching through five processes was established. The optimum technology of improving the whiteness and reducing damage on fibers has been found. The technology can provide good luster,smooth handle and relatively high strength retention to human hair used for wigs or drama articles, meeting the needs of people better. Moreover, it also has important reference value to bleaching of other colored fibers.

  6. Application of thermophilic enzymes and water jet system to cassava pulp.

    Science.gov (United States)

    Chaikaew, Siriporn; Maeno, Yuka; Visessanguan, Wonnop; Ogura, Kota; Sugino, Gaku; Lee, Seung-Hwan; Ishikawa, Kazuhiko

    2012-12-01

    Co-production of fermentable sugars and nanofibrillated cellulose from cassava pulp was achieved by the combination of thermophilic enzymes (endoglucanase, β-glucosidase, and α-amylase) and a new atomization system (Star Burst System; SBS), which employs opposing water jets. The SBS represents a key technology for providing cellulose nanofibers and improving the enzymatic saccharification of cassava pulp. Depending on the enzymes used, the production of glucose from cassava pulp treated with the SBS was 1.2- to 2.5-fold higher than that from pulp not treated with the SBS. Nanofibrillated cellulose with the gel-like property in suspension was produced (yield was over 90%) by α-amylase treatment, which completely released trapped starch granules from the fibrous cell wall structure of cassava pulp pretreated with the SBS. The SBS provides an environmentally low-impact pretreatment system for processing biomass material into value-added products. PMID:23073093

  7. 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.

  8. THE EFFECT OF TRANSITION METAL IONS-IRON ON HYDROGEN PEROXIDE BLEACHING

    Institute of Scientific and Technical Information of China (English)

    YumengZhao; ShuhuiYang; LiangSheng; YonghaoNi

    2004-01-01

    Hydrogen peroxide bleaching has been extensivelyused in high-yield pulp bleaching. Unfortunately,hydrogen peroxide can be decomposed underalkaline condition, especially when transition metalions exit. Experiments show that the valence oftransition metal ion is also responsible for thedecomposition of hydrogen peroxide.Iron ions are present in two oxidation states, Fe2+ andFe3+. They are both catalytically active to hydrogenperoxide decomposition. Because Fe3+ is brown, itcan affect the brightness of pulp directly, it can alsocombine with phenol, forming complexes which notonly are stable structures and are difficult to beremoved from pulp, but also significantly affect thebrightness of pulp because of their color.Sodium silicate and magnesium sulfate, when usedtogether, can greatly decrease hydrogen peroxidedecomposition. The optimum dosage of sodiumsilicate is about 0.1% (on solution) for Fe2~ and0.25% (on solution) for Fe3~. Adding chelants such asDTPA or EDTA with stabilizers simultaneously canobviously improve pulp brightness. For iron ions, thechelate effect of DTPA is better than that of EDTA.Under acidic conditions, sodium hyposulfite andcellulose can reduce Fe3+ to Fez+ effectively, and pulpbrightness is improved greatly. Adding sodiumthiosulfate simultaneously with magnesium sulfate,sodium silicate, and DTPA to alkaline peroxidesolution can result in higher brightness of pulp.pH is a key parameter during hydrogen peroxidebleaching, the optimum pH value should be 10.5-12.

  9. Effect of different restorative procedures on the fracture resistance of teeth submitted to internal bleaching

    Directory of Open Access Journals (Sweden)

    Andiara Ribeiro Roberto

    2012-02-01

    Full Text Available The aim of this study was to evaluate the influence of different restorative procedures on the fracture resistance of endodontically treated teeth submitted to intracoronal bleaching. Fifty upper central incisors were distributed into 5 groups: GI - healthy teeth; GII - endodontically treated teeth sealed with Coltosol; GIII - endodontically treated teeth bleached and sealed with Coltosol; GIV - endodontically treated teeth bleached and restored with composite resin; and GV - endodontically treated teeth bleached and restored with a fiberglass post and composite resin. In the bleached specimens, a cervical seal was made prior to bleaching with 38% hydrogen peroxide. The gel was applied on the buccal surface and in the pulp chamber, and was then light-activated for 45 s. This procedure was repeated three times per session for four sessions, and each group was submitted to the restorative procedures described above. The specimens were submitted to fracture resistance testing in a universal testing machine. There were statistically significant differences among the groups (p 0.05. The restorative procedures using composite resin were found to successfully restore the fracture resistance of endodontically treated and bleached teeth.

  10. Production of Cellulosic Polymers from Agricultural Wastes

    OpenAIRE

    Israel, A. U.; I. B. Obot; Umoren, S. A.; Mkpenie, V.; Asuquo, J. E.

    2008-01-01

    Cellulosic polymers namely cellulose, di-and triacetate were produced from fourteen agricultural wastes; Branch and fiber after oil extraction from oil palm (Elais guineensis), raffia, piassava, bamboo pulp, bamboo bark from raphia palm (Raphia hookeri), stem and cob of maize plant (Zea mays), fruit fiber from coconut fruit (Cocos nucifera), sawdusts from cotton tree (Cossypium hirsutum), pear wood (Manilkara obovata), stem of Southern gamba green (Andropogon tectorus), sugarcane baggase (Sac...

  11. Kinetic study of carbohydrate dissolution during tetrahydrofurfuryl alcohol/HCl pulping of rice straw

    OpenAIRE

    Chen-Lung Ho; Keng-Tung Wu; Eugene I-Chen Wang; Yu-Chang Su

    2012-01-01

    This study investigated carbohydrate dissolution during tetrahydrofurfuryl alcohol/hydrochloric acid (THFA/HCl) pulping of rice straw, and reaction kinetics equations were derived. For both cellulose and hemicellulose fractions, dissolution during pulping could be separated into two phases. In the initial stage, or phase I, of cellulose dissolution, small amounts were solubilized. In phase II, when delignification reached a level of approximately 85%, along with increases in HCl concentration...

  12. BIOCHEMICAL PULPING OF REED PRETREATED BY WHITE ROT FUNGI

    Institute of Scientific and Technical Information of China (English)

    ShiyuFu; AniwarApiz; HuaiyuZhan

    2004-01-01

    The Soda-AQ pulps were made from reed pretreated by white rot fungi Panus conchatus. Cyathus stercoreus and Pleurotus florida respectively. It was found that kappa number decreased and the brightness increased for Soda-AQ pulps from the reed treated by Pleurotus florida and Panus conchatus, but it was reverse for the pulp from reed treated by Cyathus stercoreus. The result indicated that white rot fungi Pleurotus .florida and Panus conchatus were selective to degrade lignin inreed, which were good for biopulping, but Cyathus stercoreus was preferential to degrade cellulose, which was not good for biopulping.

  13. BIOCHEMICAL PULPING OF REED PRETREATED BY WHITE ROT FUNGI

    Institute of Scientific and Technical Information of China (English)

    Shiyu Fu; Aniwar Apiz; Huaiyu Zhan

    2004-01-01

    The Soda-AQ pulps were made from reed pretreated by white rot fungi Panus conchatus,Cyathus stercoreus and Pleurotus florida respectively. It was found that kappa number decreased and the brightness increased for Soda-AQ pulps from the reed treated by Pleurotus florida and Panus conchatus, but it was reverse for the pulp from reed treated by Cyathus stercoreus. The result indicated that white rot fungi Pleurotus florida and Panus conchatus were selective to degrade lignin in reed, which were good for biopulping, but Cyathus stercoreus was preferential to degrade cellulose,which was not good for biopulping.

  14. Biohydrogen, bioelectricity and bioalcohols from cellulosic materials

    Energy Technology Data Exchange (ETDEWEB)

    Nissila, M.

    2013-03-01

    The demand for renewable energy is increasing due to increasing energy demand and global warming associated with increasing use of fossil fuels. Renewable energy can be derived from biological production of energy carriers from cellulosic biomass. These biochemical processes include biomass fermentation to hydrogen, methane and alcohols, and bioelectricity production in microbial fuel cells (MFCs). The objective of this study was to investigate the production of different energy carriers (hydrogen, methane, ethanol, butanol, bioelectricity) through biochemical processes. Hydrogen production potential of a hot spring enrichment culture from different sugars was determined, and hydrogen was produced continuously from xylose. Cellulolytic and hydrogenic cultures were enriched on cellulose, cellulosic pulp materials, and on silage at different process conditions. The enrichment cultures were further characterized. The effect of acid pretreatment on hydrogen production from pulp materials was studied and compared to direct pulp fermentation to hydrogen. Electricity and alcohol(s) were simultaneously produced from xylose in MFCs and the exoelectrogenic and alcohologenic enrichment cultures were characterized. In the end, the energy yields obtained from different biochemical processes were determined and compared. In this study, cultures carrying out simultaneous cellulose hydrolysis and hydrogen fermentation were enriched from different sources at different operational conditions. These cultures were successfully utilized for cellulose to hydrogen fermentation in batch systems. Based on these results further research should be conducted on continuous hydrogen production from cellulosic materials.

  15. ISOLATION AND CHARACTERIZATION OF NANOFIBRILLATED CELLULOSE FROM OAT HULLS

    Directory of Open Access Journals (Sweden)

    Giovanni B. Paschoal

    2015-05-01

    Full Text Available The objectives of this work were to investigate the microstructure, crystallinity and thermal stability of nanofibrillated cellulose obtained from oat hulls using bleaching and acid hydrolysis at a mild temperature (45 ºC followed by ultrasonication. The oat hulls were bleached with peracetic acid, and after bleaching, the compact structure around the cellulosic fibers was removed, and the bundles became individualized. The extraction time (30 or 60 min did not affect the properties of the nanofibrillated cellulose, which presented a higher crystallinity index and thermal stability than the raw material (oat hulls. The nanocellulose formed interconnected webs of tiny fibers with diameters of 70-100 nm and lengths of several micrometers, producing nanofibers with a relatively high aspect ratio, thus indicating that these materials are suitable for polymer reinforcement.

  16. Preparation and Characterization of Super Absorbent Resin from Natural Cellulose

    Institute of Scientific and Technical Information of China (English)

    李杰; 马凤国; 谭惠民

    2003-01-01

    The grafting polyacrylamide onto wood pulp cellulose (cell-g-PAM) was performed with cerous ammonium nitrate as the initiator and hydrolyzed to produce the super absorbent resin. The FTIR shows that the polyacrylamide is grafted on the cellulose. After hydrolyzation, part of acrylamino groups are transformed into carboxyl groups. The XRD analysis shows that the graft polymerization occurred at the amorphous section and the surface of the crystal section of cellulose. The SEM graph reveals that there is a layer of polymer on the surface of cellulose fiber and the fibril structure of the cellulose surface is covered. After hydrolyzation, the surface of the product is different from that of cell-g-PAM's and the surface is scraggy. The technical conditions to prepare high water absorbent resin were confirmed. Through the radical graft copolymerization, the high water absorbent resin can be produced from wood pulp cellulose.

  17. WOOD CELLULOSE REMOVAL BY MEANS OF SELF- HYDROLYSIS TREATMENT

    Directory of Open Access Journals (Sweden)

    Dalton Longue Júnior

    2011-09-01

    Full Text Available The objective of this study was to assess the impact of removing hemicelluloses from chips of eucalyptus wood by self-hydrolysis treatment (H2O and on the subsequent ‘kraft’ process behavior and pulps bleachability and quality. The self-hydrolysis treatments were conducted at temperatures of 152°C (30, 45 and 60 minutes; 160°C (15, 30 and 45 minutes; and 170°C (5, 10, 15, 20 and 30 minutes; water: wood ratio of 4:1 m3/t. Normal chips (reference and self-hydrolyzed chips at 170°C during 5, 15 and 30 minutes were submitted to ‘kraft’ cooking up to kappa number 16 – 18 and the resulting pulp was bleached using the O/OD (EPO DD sequence. According to the results obtained, self-hydrolyzing the chips at 170°C for 30 minutes allowed the removal of up to 60% hemicelluloses. Cooking yield of the self-hydrolyzed chips for 30 minutes was around 6% smaller and pentosan content 88% lower than that of the regular chips. The efficiency of delignification with oxygen of the pulp derived from self-hydrolyzed chips for 30 minutes was of 75%, compared to 43.6% of the reference-pulp, and the bleaching cost using the O/OD (EPO DD sequence was US$ 7/adt per pulp, lower that that of the reference-pulp. The effluent originated from bleaching the pulp derived from the self-hydrolyzed chips presented lower values of COD (39.6%, color (21.3% and AOX (51.6%, compared to that of the reference-pulp.

  18. Extraction of palm tree cellulose and its functionalization via graft copolymerization.

    Science.gov (United States)

    Al-Hoqbani, Abdulmajeed A; Abdel-Halim, E S; Al-Deyab, Salem S

    2014-09-01

    The work in this paper was planned with the aim of extracting the cellulosic component of palm tree waste and functionalizing this cellulose through graft copolymerization with acrylic acid. The cellulose extraction included hot alkali treatment with aqueous sodium hydroxide to remove the non-cellulosic binding materials. The alkali treatment was followed by an oxidative bleaching using peracid/hydrogen peroxide mixture with the aim of removing the rest of non-cellulosic materials to improve the fiber hydrophilicity and accessibility towards further grafting reaction. Optimum conditions for cellulose extraction are boiling in 5% (W/V) NaOH in a material to liquor ratio of 1:20 for 1 h then bleaching with 60 ml/l bleaching mixture at initial pH value of 6.5 for 30 min. The pH of the bleaching medium is turned to the alkaline range 11 and bleaching continues for extra 30 min. Graft copolymerization reaction was initiated by potassium bromate/thiourea dioxide redox system. Optimum conditions for grafting are 30 mmol of potassium bromate, 30 mmol of thiourea dioxide and 150 g of acrylic acid (each per 100 g of cellulose). The polymerization reaction was carried out for 120 min at 50°C using a material to liquor ratio of 1:20. PMID:25020080

  19. Isolation and characterization of pulp from sugarcane bagasse and rice straw

    International Nuclear Information System (INIS)

    The amount of sugarcane bagasse and rice straw in the state of Perlis (Malaysia) is abundant while its utilization is still limited. One of the alternatives for the bagasse and straw utilization is as pulp raw material. This paper reviews on pulp from sugarcane bagasse and rice straw and its suitability for paper production. In this study, the pulp was extracted by the Soxhlet extraction method. The objective of this study was to investigate the cellulose, lignin and silica content of the pulp from sugarcane bagasse and rice straw. For rice straw, the presence of large amount of pentosanes in the pulp and black liquors, which also contain silica were decreased the using of straw in the paper industry. Therefore, formic acid pulping and NaOH treatment are studied to reduce or prevent silica. The isolated pulp samples were further characterized by Scanning Electron Microscope (SEM) to investigate their fiber dimensions. (Author)

  20. Gas Chromatography Analysis of Resin and Fatty Acids from Laboratory Generated Bleach Plant Effluents

    Institute of Scientific and Technical Information of China (English)

    Chhaya Sharma; S. Mohanty; S. Kumar; N.J. Rao

    2007-01-01

    Laboratory generated spent bleached liquor from the chlorination, caustic extraction stage of mixed wood kraft pulp processing has been analyzed both qualitatively and quantitatively for various resin & fatty acids by using GC. A number of resin acids,saturated and unsaturated fatty acids, chloro fatty and resin acid have been detected and their concentrations are estimated. The results are compared with results on different agriculture residue/hardwood pulps, which were reported earlier. The concentrations of various compounds detected have also been compared with their reported LC50 values.

  1. Biological treatments affect the chemical composition of coffee pulp

    NARCIS (Netherlands)

    Ulloa Rojas, J.B.; Verreth, J.A.J.; Amato, S.; Huisman, E.A.

    2003-01-01

    Biological treatments were applied to fresh coffee pulp (CoP) to improve its nutritive value for monogastric animals by reducing its content of cellulose and antinutritional factors (ANFs) such as total phenols, tannins and caffeine. Treatments were: (1) ensiling with 0, 50 and 100 g kg¿1 molasses f

  2. Esthetic rehabilitation with tooth bleaching, enamel microabrasion, and direct adhesive restorations.

    Science.gov (United States)

    Bezerra-Júnior, Douglas Machado; Silva, Luciana Mendonça; Martins, Leandro de Moura; Cohen-Carneiro, Flávia; Pontes, Danielson Guedes

    2016-01-01

    The aim of this case report is to report esthetic rehabilitation with combined tooth bleaching, enamel microabrasion, and anterior restoration replacement in a 26-year-old man. Clinical examination showed deficient restorations in the maxillary anterior teeth, significant discoloration of the maxillary left central incisor, and hypoplastic stains affecting the maxillary right lateral incisor. A radiograph of the left central incisor showed satisfactory endodontic treatment, allowing preparation for the walking bleach technique. For 3 weeks, 37% carbamide peroxide in the pulp chamber was renewed every week. In-office bleaching with 35% hydrogen peroxide was also performed on the maxillary teeth. After 21 days, all teeth had been bleached to shade A1. After bleaching was completed, enamel microabrasion of the maxillary right lateral incisor was conducted with 6% hydrochloric acid. In later sessions, microhybrid composite resin restorations were placed in all 4 maxillary incisors. A combination of dental bleaching techniques, enamel microabrasion, and resin restorations was a successful and conservative choice for reestablishing the natural appearance of discolored teeth, improving the self-esteem of the patient. PMID:26943091

  3. Conversion of henequen pulp to microbial biomass by submerged fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Blancas, A. (Center of Scientific Research of Yucatan, Merida, Mexico); Alpizar, L.; Larios, G.; Saval, S.; Huitron, C.

    1982-01-01

    Mexico has cellulosic by-products that could be developed as renewable food sources for animal consumption. Sugarcane bagasse and henequen pulp are the most important of these materials because they are abundant, cheap, renewable, and nontoxic, in addition to being underutilized. A significant research and development effort has centered on the production of single-cell protein from sugarcane begasse. Nevertheless, there are no large-scale processes that utilize this substrate as a source of carbon, probably because of the extensive physical or chemical pretreatment that is needed. Henequen pulp is a by-product which is obtained in large amounts in southeastern Mexico in the process of removing fibers from the leaves of agave (sisal). A group has been working on a fermentative process that will increase the protein content of the henequen pulp by microbial conversion. The primary aim is to carry out the conversion without chemical pretreatment of the substrate and without a separation step for cells and residual substrate. A gram-negative cellulolytic bacteria has been isolated which grows well on microcrystalline cellulose, pectin, and xylane and it is able to convert an appreciable fraction of henequen pulp to microbial biomass. In this article, some results on the effect of substrate and nitrogen source concentration, on the protein enrichment of the henequen pulp, as well as the content of essential amino acids of fermented henequen pulp are presented. 4 figures.

  4. RELATIVE IMPORTANCE OF WOOD DENSITY AND CARBOHYDRATE CONTENT ON PULPING YIELD AND PRODUCT QUALITY

    Institute of Scientific and Technical Information of China (English)

    Colodette, J.L.; Mokfienski, A.; Gomide,J.L.; Oliveira, R.C.

    2004-01-01

    The purpose of this study was to evaluate basic density, chemical composition and fiber dimensions of ten Eucalyptus sp wood samples and verify the impact of this set of parameters and their combination on the Kraft pulping process yield and on bleached pulp quality. Ten eucalypt woods of different species, with basic densities varying from 365 to 544 kg/m3 and total wood carbohydrate contents varying from 70.0 to 74.5%, were transformed into kraft pulp of kappa number 17-18and bleached to 90% ISO brightness by the sequenceOD (PO)D. Wood basic density showed strongercorrelations with fiber dimensions, pulping yield and pulp quality than did chemical composition. Lighter woods resulted in higher yields. However, wood specific consumption was lower for denser woods,even though these demanded more drastic pulping conditions to achieve a given kappa number. The pulp quality results suggest that lower density woods should be directed towards fabrication of refined paper (printing and writing grades) while the denser woods be directed to the sanitary papers segment (tissue grades).

  5. SIMULTANEOUS DETERMINATION OF CHLORINE DIOXIDE AND HYPOCHLOROUS ACID IN BLEACHING SYSTEM

    OpenAIRE

    Qiang Wang; Kefu Chen; Jun Li Mail; Jun Xu; Shanshan Liu Mail

    2011-01-01

    This study has demonstrated a rapid spectroscopic method for the determination of chlorine dioxide and hypochlorous acid concentrations in the pulp bleaching processes. It was found that chlorine dioxide and hypochlorous acid have an isosbestic wavelength of 295 nm. The soluble lignin in such a system is the main interference, but can be corrected by determining the absorbances at 295 nm, 380 nm, and 480 nm. Thus, based on the spectroscopic measurements at 295 nm (the isosbestic point wavelen...

  6. THE EFFECT OF HEMICELLULOSE EXTRACTION ON FIBER CHARGE PROPERTIES AND RETENTION BEHAVIOR OF KRAFT PULP FIBERS

    Directory of Open Access Journals (Sweden)

    Katja Lyytikäinen

    2011-02-01

    Full Text Available The integrated forest biorefinery (IFBR concept provides a promising opportunity for the development of the pulp and paper industry. One proposed next generation technology for an integrated forest biorefinery is the extraction of hemicelluloses, allowing the co-production of pulp and different hemicellulose-based chemicals. In addition to paper properties, hemicelluloses are known to be important for the function of cationic papermaking additives, because they are the main source of charged groups in fibers. This paper shows that the alkaline extraction of hemicelluloses from bleached kraft pulp decreases both the total and surface charge of the pulps. It was found that the decreased fiber charge leads to increased filler retention with fixed retention aid dosage. The reduction observed in the fiber surface charge for alkali-extracted pulp was mainly attributed to the decrease in the amount of anionic groups located in fines.

  7. The effects of bleach plant effluent recycle in kraft mill green liquors

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, B.M.; Uloth, V.C. [Pulp and Paper Research Inst. of Canada, Vancouver, BC (Canada); Dorris, G.M. [Pulp and Paper Research Inst. of Canada, Pointe Claire, PQ (Canada); Stafford, E. C.

    1995-12-31

    A new approach to reducing or eliminating effluent flows from a kraft mill through process changes and by recycling, was presented. A closed system experiment was conducted in which bleach plant effluents and green liquors were used to simulate effluent recycling to the recausticizing area in place of fresh water. Results showed that with current levels of water use, acid effluents from bleaching of softwood pulp could be recycled to the recausticizing area if a 5-18 per cent loss in causticizing efficiency and a 10 per cent decrease in the lime mud settling rate was tolerable. High levels of sodium chloride did not always reduce causticizing efficiency. It was found that bleach plant water usage was very high in the plants studied. New ways to minimize water use in the plant must be found if a significant degree of closure is to be achieved. 15 refs., 6 tabs., 8 figs.

  8. Influence of process variables on the properties of laccase biobleached pulps.

    Science.gov (United States)

    Martin-Sampedro, Raquel; Miranda, Jesús; García-Fuentevilla, Luisa L; Hernández, Manuel; Arias, Maria E; Diaz, Manuel J; Eugenio, Maria E

    2015-01-01

    A laccase stage can be used as a pre-treatment of a standard chemical bleaching sequence to reduce environmental concerns associated to this process. The importance of each independent variable and its influence on the properties of the bleached pulp have been studied in depth in this work, using an adaptive network-based fuzzy inference system (ANFIS) with four independent variables (laccase, buffer, mediator and oxygen) as input. Eucalyptus globulus kraft pulp was biobleached using a laccase from Pycnoporus sanguineus and a natural mediator (acetosyringone). Later, an alkaline extraction and a hydrogen peroxide treatment were applied. Most biobleaching processes showed a decrease in kappa number and an increase in brightness with no significant impact on the viscosity values, compared with the control. Oxygen was the variable with the smallest influence on the final pulp properties while the laccase and buffer solution showed a significant influence. PMID:25085529

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

    OpenAIRE

    Andreu Terrén, Glòria; Vidal Lluciá, Teresa

    2012-01-01

    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 co...

  10. Influence of extraction techniques on antioxidant properties and bioactive compounds of loquat fruit (Eriobotrya japonica Lindl.) skin and pulp extracts

    OpenAIRE

    Delfanian, Mojtaba; Esmaeilzadeh Kenari, Reza; Sahari, Mohammad Ali

    2015-01-01

    In this study, the bioactive compounds of loquat fruit (Eriobotrya japonica Lindl.) skin and pulp extracted by two extraction methods (solvent and ultrasound-assisted) with three solvents (ethanol, water and ethanol–water) were compared to supercritical fluid extraction. The antioxidant activities of skin and pulp extracts were evaluated and compared to tertiary butylhydroquinone (TBHQ) using 2, 2-diphenyl-1-picrylhydrazyl (DPPH˙) radical scavenging, β-carotene bleaching, and the Rancimat ass...

  11. Cellulose fractionation with IONCELL-P.

    Science.gov (United States)

    Stepan, A M; Monshizadeh, A; Hummel, M; Roselli, A; Sixta, H

    2016-10-01

    IONCELL-P is a solvent fractionation process, which can separate pulps almost quantitatively into pure cellulose and hemicellulose fractions using IL-water mixtures. In this work the role of the molecular weight of cellulose on its solubility in ionic liquid-water mixtures is studied. The aim of this study was to understand and identify the determining factors of this IONCELL-P fractionation. Cotton linters (CL) served as model cellulose substrate and was degraded by ozone treatment to adjust the molecular weight to that of hemicelluloses and low molar mass cellulose in commercial pulps. The ozone treated CLs were subjected to the IONCELL-P process using 1-ethyl-3-methylimidazolium acetate ([emim][OAc]) and water mixtures with a water content between 13.5 and 19wt%. Based on the molar mass distributions of dissolved and undissolved cellulose the effect of the molecular weight of cellulose in IL-water mixture appears to be a key factor in the fractionation process. PMID:27312618

  12. Characterization of cell wall degrading enzymes from Chrysosporium lucknowense C1 and their use to degrade sugar beet pulp

    NARCIS (Netherlands)

    Kühnel, S.

    2011-01-01

    Key words: Pectin, arabinan, biorefinery, mode of action, branched arabinose oligomers, ferulic acid esterase, arabinohydrolase, pretreatment Sugar beet pulp is the cellulose and pectin-rich debris remaining after sugar extraction from sugar beets. In order to use sugar beet pulp for biorefinery pu

  13. INCORPORATION OF BARK AND TOPS IN EUCALYPTUS GLOBULUS WOOD PULPING

    Directory of Open Access Journals (Sweden)

    Isabel Miranda,

    2012-07-01

    Full Text Available Bark and the tops of E. globulus trees were considered for kraft pulping under industrial conditions. Pulping experiments included wood, bark, tops, and composite samples. Top wood had an average chemical composition most similar to that of wood but with somewhat lower cellulose content (52.8% vs. 56.9% and higher lignin content (18.8% vs. 17.8%. There was also a small difference between tops and wood for non-polar extractives, which were higher for tops (2.0% vs. 1.4%. Bark had a less favorable chemical composition with more extractives, especially polar extractives (5.3% vs. 1.6% and 1% NaOH solubility (19.9% vs. 12.2%, pentosans (23.7% vs. 21.3%, and ash (2.9% vs. 1.0%, although the fiber length was higher (1.12 mm vs. 0.98 mm. The kraft pulps obtained using bark showed significantly lower yield, delignification degree, and strength properties but had a quicker response to refining. The incorporation of tops and bark in the wood pulping in levels below or similar to a corresponding whole-stem, however, had a limited effect on pulp yield, kappa number, refining, and pulp strength properties. These additional raw-materials, which were estimated to be 26% of the commercial stem wood (14% bark and 12% tops, may therefore be considered in enlarging the eucalypt fiber feedstock in kraft pulping.

  14. Pollution prevention in the pulp and paper industry

    Energy Technology Data Exchange (ETDEWEB)

    Jenkins, P.G. [Science Applications International Corp., Olympia, WA (United States)

    1995-09-01

    Probably no other industry has made as much progress as the kraft pulp and paper industry in reclaiming waste products. About half of the wood used in making pulp is cellulose; the reclamation of the other ingredients in the wood constitutes a continuing evolution of pollution prevention and economic success. The by-products of chemical pulping include turpentine used in the paint industry, lignosulfonates used as surfactants and dispersants, ``tall oil`` used in chemical manufacturing, yeast, vanillin, acetic acid, activated carbon, and alcohol. Sulfamic turpentine recovered in the kraft process is used to manufacture pine oil, dimethyl sulfoxide (DMSO), and other useful chemical products. In addition, the noncellulose portion of the wood is used to provide energy for the pulping process through the combustion of concentrated black liquor. Over 75% of the pulp produced in the US is manufactured using the kraft process. Because of the predominance of the kraft process, the remainder of this section will address pollution prevention methods for kraft pulp and paper mills. Some of these techniques may be applicable or adaptable to other pulping processes, especially sulfite mills. The major steps in the kraft process are described, followed by a discussion of major wastestreams, and proven pollution prevention methods for each of these steps.

  15. Morphological, thermal, and mechanical properties of starch biocomposite films reinforced by cellulose nanocrystals from rice husks

    OpenAIRE

    Nurain Johar; Ishak Ahmad

    2012-01-01

    A series of glycerol-plasticized starch composites reinforced by rice-husk cellulose nanocrystals was successfully fabricated through the solution casting technique. The rice husks must undergo alkali treatment, bleaching, and sulphuric acid hydrolysis before cellulose nanocrystals can be produced. The cellulose nanocrystal content used as filler was varied from 0 to 10 wt%. The thermal stability of the composite were analysed by thermogravimetric analysis (TGA) and derivative thermogravimetr...

  16. 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. PMID:27099940

  17. EVALUATION OF A NEW LACCASE PRODUCED BY STREPTOMYCES IPOMOEA ON BIOBLEACHING AND AGEING OF KRAFT PULPS

    Directory of Open Access Journals (Sweden)

    M. Enriqueta Arias

    2011-06-01

    Full Text Available The aim of this work is to prove the suitability of a new alkaline and halo-tolerant bacterial laccase (SilA produced by Streptomyces ipomoea CECT 3341 to enhance the conventional chemical bleaching process of an industrial eucalyptus kraft pulp. The laccase used for this study was a recombinant laccase obtained from cultures of E. coli BL21 (DE3 grown in LB liquid medium. The biobleaching experiment was carried out on Eucalyptus globulus kraft pulps using the above mentioned laccase and acetosyringone as natural mediator. Then, an alkaline extraction and further hydrogen peroxide steps were applied to evaluate the efficiency of the laccase-mediator system as a pretreatment in the bleaching sequences. Biobleached pulps showed a kappa number decrease and a brightness increase without decreasing the viscosity values significantly. Also, a reduction in the consumption of hydrogen peroxide was observed when the enzymatic treatment was applied to the pulp. CIE L*a*b* and CIE L*C* color coordinates measured in pulps demonstrated that among all treatments applied to pulps, the laccase-acetosyringone system presented the best optical properties even after an accelerated ageing process. Finally, it is also remarkable that during this treatment 64% of the laccase activity remained unaltered.

  18. ON THE BLACK LIQUOR AND RECYCLE COOKING OF AS-AQ STRAW PULP

    Institute of Scientific and Technical Information of China (English)

    HaiqiangShi; BeihaiHe; BingyueLiu

    2004-01-01

    Thick black liquor, thin black liquor and solid state sodium hydroxide are added to the liquor treated by sulfur dioxide, then the blended liquor is used to recycle cooking of straw pulp. The black liquor, separated liquor and pulp of every cycles are analyzed respectively. Result shows that the content of lignin and organism in recycle black liquor and separated liquor increases faster in the first three cycles and then continues to increase slowly till four or five times, after that it trends to a stable state. The main organism separated fi'om waste liquor of AS-AQ treated by sulfur dioxide is alkali-lignin,above 50% of total lignin in black liquor. The yield of pulp made fi'om recycle cooking is steady, the hardness of pulp has a great improvement with recycle cooking. The brightness of pulp reduces correspondingly before bleaching, and after bleaching the brightness of pulp is relatively high and steady at the same sodium hypo chlorite dosage.

  19. 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.

  20. 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

  1. On the behaviour of lignin rich pulps upon irradiation with light. Pt. 1

    International Nuclear Information System (INIS)

    The work deals with investigations on changes taking place in brightness, lignin content and methoxyl content upon irradiation of differently prepared unbleached and semi-bleached pulps from beech and spruce with light of more or less the same the spectral distribution as daylight. The results show that the change in brightness depends to a large extent on the used pulping method as well as on the pulping conditions. Pulps prepared according to the alkaline sulphite method as well as according to the soda method display an increase in brightness upon exposure to light. The behaviour of pulps produced by the neutral-sulphite-semichemical method (NSSC-Method) depends mainly upon the pulping conditions. Pulps produced under relatively mild conditions regarding alkalinity and cooking temperature show a great decrease in brightness by irradiation. Pulping at relatively high alkalinity and temperature leads to pulps, which show at first a slight increase in brightness, after which practically no change in colour occurs. Bisulphite pulps decrease in brightness under the same conditions. In all cases there was a significant decrease in the lignin content due to light irradiation. The lignin content of NSSC-pulps from beech wood decreases at a higher rate than the lignin content of pulps prepared by the alkaline sulphite method. The loss in the methoxyl content was in all cases higher than that of lignin. The amount of water-soluble extractives increases by lengthening the exposure time, the pH-value of the extractives decreases in the same direction. The characteristic maximum at 280 nm decreases in intensity to a large extent after irradiation. (orig.)

  2. Intra-pulpal temperature rise of different tooth types during dental bleaching supported by an Er,Cr:YSGG laser. A pilot study.

    Science.gov (United States)

    Strakas, D; Tolidis, K; Koliniotou-Koumpia, E; Vanweersch, L; Franzen, R; Gutknecht, N

    2016-01-01

    The purpose of this pilot in vitro study was to evaluate the temperature increase in the pulp chamber of the teeth, during Er,Cr:YSGG bleaching, as well as to show which teeth are the most susceptible in terms of pulp temperature increase during laser-activated bleaching treatment. Although Er:YAG studies have been published on this subject, it is the first time Er,Cr:YSGG wavelength is tested. Fifteen teeth were tested--3 each of the following--(maxillary central incisors, lateral incisors, canines, premolars and mandibular incisors). The bleaching procedure comprised an Er,Cr:YSGG laser (2780 nm, Waterlase MD, Biolase, USA) and a yellow-coloured bleaching agent with a concentration of 38 % H2O2 (Power whitening, WHITEsmile GmbH, Germany). The tip used was a 6-mm long Z-type glass tip (MZ8) of a 800 μm diameter. Average output power was set to 1.25 W, pulse duration 700 μs (S-mode), whilst the pulse repetition rate was 10 Hz. The results showed that the most susceptible teeth in terms of pulp temperature increase were the lateral maxillary incisors and the mandibular incisors. The mean temperature increase on these teeth was 1.06 and 1.00 °C, respectively, on 60 s Er,Cr:YSGG-supported bleaching. PMID:26526961

  3. 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.

  4. Coral Mortality and Bleaching Output

    Science.gov (United States)

    COMBO is a spreadsheet-based model for the use of managers, conservationists, and biologists for projecting the effects of climate change on coral reefs at local-to-regional scales. The COMBO (Coral Mortality and Bleaching Output) model calculates the impacts to coral reefs from...

  5. PREPARATION AND CHARACTERIZATION OF BAMBOO NANOCRYSTALLINE CELLULOSE

    Directory of Open Access Journals (Sweden)

    Mengjiao Yu,

    2012-02-01

    Full Text Available Nanocrystalline cellulose (NCC has many potential applications because of its special properties. In this paper, NCC was prepared from bamboo pulp. Bamboo pulp was first pretreated with sodium hydroxide, followed by hydrolysis with sulfuric acid. The concentration of sulfuric acid and the hydrolysis time on the yield of NCC were studied. The results showed that sulfuric acid concentration had larger influence than the hydrolysis time on the yield of NCC. When the temperature was 50oC, the concentration of sulfuric acid was 48wt% and the reaction time was 30 minutes, a high quality of nanocrystalline cellulose was obtained; under these conditions, the length of the nanocrystalline cellulose ranged from 200 nm to 500 nm, the diameter was less than 20 nm, the yield was 15.67wt%, and the crystallinity was 71.98%, which is not only higher than those of cellulose nanocrystals prepared from some non-wood materials, but also higher than bamboo cellulose nanocrystals prepared by other methods.

  6. Penetration Capacity, Color Alteration and Biological Response of Two In-office Bleaching Protocols.

    Science.gov (United States)

    Cintra, Luciano Tavares Angelo; Benetti, Francine; Ferreira, Luciana Louzada; Gomes-Filho, João Eduardo; Ervolino, Edilson; Gallinari, Marjorie de Oliveira; Rahal, Vanessa; Briso, André Luiz Fraga

    2016-01-01

    Hydrogen peroxide (H2O2) penetrates into the dental hard tissues causing color alteration but also alterations in pulpal tissues. Hard-tissue penetration, color alteration and the pulp response alterations were evaluated for two in-office bleaching protocols with H2O2. For trans-enamel/dentin penetration and color alteration, discs of bovine teeth were attached to an artificial pulp chamber and bleached according to the groups: BLU (20% H2O2 - 1x50 min, Whiteness HP Blue); MAX (35% H2O2 - 3x15 min, Whiteness HP Maxx); Control (1x50 min, placebo). Trans-enamel/dentin penetration was quantified based on the reaction of H2O2 with leucocrystal violet and the color analyzed by CIELab System. Twenty Wistar rats were divided into two groups (BLU and MAX) and their maxillary right molars were treated according to the same protocols of the in vitro study; the maxillary left molars were used as controls. After 2 days, the animals were killed and their maxillae were examined by light microscopy. The inflammation of pulp tissue was scored according to the inflammatory infiltrate (1, absent; 2, mild; 3, moderate; 4, severe/necrosis). Data were analyzed by statistical tests (α=0.05). MAX showed higher trans-enamel/dentinal penetration of H2O2 (p0.05), and different when compared to Control group (pbleaching protocols using lower concentrations of hydrogen peroxide should be preferred due to their reduced trans-enamel/dentinal penetration since they cause less pulp damage and provide same bleaching efficiency. PMID:27058379

  7. Production of bacterial cellulose and enzyme from waste fiber sludge

    OpenAIRE

    Cavka, Adnan; Guo, Xiang; Tang, Shui-Jia; Winestrand, Sandra; Jönsson, Leif J.; Hong, Feng

    2013-01-01

    Background: Bacterial cellulose (BC) is a highly crystalline and mechanically stable nanopolymer, which has excellent potential as a material in many novel applications, especially if it can be produced in large amounts from an inexpensive feedstock. Waste fiber sludge, a residue with little or no value, originates from pulp mills and lignocellulosic biorefineries. A high cellulose and low lignin content contributes to making the fiber sludge suitable for bioconversion, even without a thermoc...

  8. Synthesis and Characterization of Graft Copolymer Rice Straw Cellulose-Acrylamide Hydrogels Using Gamma Irradiation

    International Nuclear Information System (INIS)

    Rice straw cellulose available as waste biomass was graft copolymerized with acrylamide monomer by simultaneous gamma irradiation as initiator. The effects of bleaching of cellulose and irradiation dose were evaluated. Evidence of grafting is obtained from comparison of Fourier Transfer Infrared (FTIR) of the cellulose and grafted cellulose. X-ray diffraction analysis shows that crystallinity was reduced through graft copolymerization. Kinetic investigations of the graft copolymerization were also carried out, and the rate constant parameter (kp/kt0.5) has been found to be 4.9922 l0.5. mol-0.5.s-0.5. The results show that for the same dose, grafting efficiency is higher with bleached cellulose form than with unbleached form. The grafting efficiency and the gel fraction increases with increasing total irradiation doses. At higher radiation doses crosslink density starts to increase considerably while swelling degree decreases with the increasing crosslink density. (author)

  9. Preparation and application of cationized pulp fiber as a papermaking wet-end additive

    Institute of Scientific and Technical Information of China (English)

    XIE Wei; FENG Hai-li; QIAN Xue-ren

    2008-01-01

    Cationized pulp fibers (CPF) were prepared by the adsorption of a novel biodegradable cationic ester quaternary ammonium salt (31441) on bleached softwood kraft pulp fibers. The optimized conditions for the CPF preparation were: 4% of 31441 (based on oven-dry pulp), 80°C and 30 min. The CPF was characterized by FT-IR, SEM and XPS. Experimental results showed that the CPF improved the retention of precipitated calcium carbonate (PCC) filler significantly. With 0.9% CPF (based on oven-dry pulp), the retention of PCC increased from 57.53% to 72.21%. The physical properties of paper were also slightly improved. The tensile strength and burst strength of the paper with CPF were higher than those with CPAM. CPF addition had no effect on the stock drainage.

  10. Physicochemical characteristics of rayon grade dissolving pulp and effects of metallic-ions on the viscose rayon process

    International Nuclear Information System (INIS)

    Pakistan imports rayon grade pulp from different countries for viscose rayon fibre manufacturing. Samples of imported pulp were collected and analyzed for alpha-cellulose, hemicellulose, calcium, magnesium, silica, copper, manganese, and iron. Moisture, ash content, cuprammonium viscosity, degree of polymerization, alkali absorption, and colour brightness were also determined. The results showed that all these parameters varied from sample to sample. The cotton linter pulp contained high alpha-cellulose content (94-98%) as compared to the softwood pulp (89.7-95%). Degree of polymerization of all samples was above 500 and varied from 500-750 ml/g. the study showed that higher manganese and copper content in cotton decreased the degree of polymerization. Iron above the standard value (7-10 ppm) affected the brightness of fibre, as observed in the case of cotton linter pulp (imported from China). The percentage of ash was less than 0.25% in all samples studied. (author)

  11. Pretreatment with xylanase and its significance in hemicellulose removal from mixed hardwood kraft pulp as a process step for viscose.

    Science.gov (United States)

    Kaur, Prabhjot; Bhardwaj, Nishi K; Sharma, Jitender

    2016-07-10

    The upturn of viscose fiber market has triggered an augmented dissolving pulp usage over the last decade. Dissolving pulp is feasible to obtain from kraft pulp after two essential steps including hemicellulose removal and subsequent pulp activation. Prerequisite of conversion being hemicellulose reduction can be gently done by using xylanase treatment prior to alkali extraction. Herein, the significance of xylanase treatment and the optimum xylanase dose required in conjunction with subsequent alkali extraction was investigated. An increase in xylanase dose prior to alkali extraction had no significant effect on pentosans while the Fock reactivity and viscosity both improved at the dose of 50AXU/g. Also, alkali extraction without xylanase pretreatment resulted in decreased Fock reactivity, alpha cellulose, brightness and viscosity of paper grade pulp. A moderate dose of xylanase prior to alkali extraction can thus be used to facilitate the hemicellulose removal while simultaneously protecting the native structure of cellulose. PMID:27106156

  12. INVESTIGATION ON THE CAUSES OF EUCALYPTUS KRAFT PULP BRIGHTNESS REVERSION

    OpenAIRE

    Kátia M. M. Eiras; Jorge Luiz Colodette; Ana Márcia M. L. Carvalho

    2005-01-01

    Some high brightness eucalyptus Kraft pulps have shown poor brightness stability. In most cases, the causes have notbeen identified and permanent solutions have not been found. This work focused on evaluating the brightness stability profile of pulpsbleached by in sequences such as O(DC)(PO)DD, O(DC)(PO)DP, OD(PO)DD, OD(PO)DP, ODHT(PO)DD, ODHT(PO)DP, OA/D(PO)DD, OA/D(PO)DP, OAD(PO)DD and O(Ze)D(PO). Brightness stability tests induced by according to Tappi UM200 procedureon samples bleached to...

  13. OPTIMIZING EUCALYPTUS PULP REFINING

    Institute of Scientific and Technical Information of China (English)

    VailManfredi

    2004-01-01

    This paper discusses the refining of bleachedeucalyptus kraft pulp (BEKP).Pilot plant tests were carded out in to optimize therefining process and to identify the effects of refiningvariables on final paper quality and process costs.The following parameters are discussed: pulpconsistency, disk pattern design, refiner speed,energy input, refiner configuration (parallel or serial)and refining intensity.The effects of refining on pulp fibers were evaluatedagainst the pulp quality properties, such as physicalstrengths, bulk, opacity and porosity, as well as theinteractions with papermaking process, such as papermachine runnability, paper breaks and refiningcontrol.The results showed that process optimization,considering pulp quality and refining costs, wereobtained when eucalyptus pulp is refined under thelowest intensity and the highest pulp consistencypossible. Changes on the operational refiningconditions will have the highest impact on totalenergy requirements (costs) without any significanteffect on final paper properties.It was also observed that classical ways to control theindustrial operation, such as those based on drainagemeasurements, do not represent the best alternative tomaximize the final paper properties neither the papermachine runability.

  14. ABSORBENT MATERIALS BASED ON KRAFT PULP: PREPARATION AND MATERIAL CHARACTERIZATION

    Directory of Open Access Journals (Sweden)

    Fredrik Wernersson Brodin,

    2012-02-01

    Full Text Available Today, petroleum-based superabsorbents are widely used, but interest in renewable alternatives is on the rise. This study presents two wood-based absorbent materials suitable for various absorption applications as an alternative to petroleum-based products. Never-dried bleached kraft pulp was treated with TEMPO-oxidation, and new carboxylate and aldehyde groups were introduced. It was found that the aldehyde groups contributed to the wet integrity of the absorbent materials, possibly by the formation of hemiacetal bonds. After oxidation, the pulp fibers were gradually disintegrated, and size analysis showed that the disintegration rate was enhanced by an increase in the charge of the oxidant. Freeze drying produced a porous foam with a large surface area that enabled a rapid absorption rate as well as a reasonably high absorption capacity even for absorption under load. Air drying formed a compact film with a slow absorption rate but with a high final capacity for absorption.

  15. High biodegradation levels of 4,5,6-trichloroguaiacol by Bacillus sp. isolated from cellulose pulp mill effluent Altos níveis de biodegradação do 4,5,6-tricloroguaiacol por Bacillus sp. isolado de efluente de indústria de polpa de celulose

    Directory of Open Access Journals (Sweden)

    E.C. Tondo

    1998-10-01

    Full Text Available An aerobic Gram positive spore-forming bacterium was isolated from cellulose pulp mill effluent. This microorganism, identified as Bacillus sp. and named IS13, was able to rapidly degrade the organic chlorinated compound 4,5,6-trichloroguaiacol (4,5,6-TCG from a culture containing 50 mg/l, which corresponds to about 3x104 times the concentration found in the original effluent. The biodegradation of this compound, usually found in cellulose pulp mill effluents, was evaluated by spectrophotometry and gas chromatography analysis. During 4,5,6-TCG decreasing, the lack of by-products had shown by such analysis lead to verify the possibility of either adsorption or absorption of 4,5,6-TCG by the cells, instead of real biodegradation. There were no traces of 4,5,6-TCG after lysozyme and SDS cell disruption. Vigorous extraction was applied before spectrophotometry analysis and there was no release of residual 4,5,6-TCG. Plasmid isolation was attempted by using different protocols. The best results were reached by CTAB method, but no plasmid DNA was found in Bacillus sp. IS13. The results suggest that genes located at the bacterial chromosome might mediate the high decrease of 4,5,6-TCG. The importance of this work is that, in being a natural ocurring microorganism, Bacillus sp. IS13, can be used as inoculum in plant effluents to best organochlorinated compounds biodegradation.Isolou-se uma bactéria gram positiva, esporulada a partir de efluente de fábrica de polpa de celulose. Esse microrganismo, identificado como Bacillus sp. e nomeado IS13, foi capaz de degradar rapidamente o composto orgânico clorado 4,5,6-tricloroguaiacol (4,5,6-TCG presente em meio de cultura a uma concentração de 50mg/L. Essa concentração equivale a 3x104 vezes mais 4,5,6-TCG que a concentração encontrada no efluente original. A biodegradação desse composto foi analisada por espectrofotometria de varredura e cromatografia gasosa. A falta de sub-produtos de degrada

  16. Efeito da adição de polpa, carboximetilcelulose e goma arábica nas características sensoriais e aceitação de preparados em pó para refresco sabor laranja Effect of adding pulp, carboxymethyl cellulose and arabic gum to sensory characteristics and acceptance of powdered orange-flavored refreshments

    Directory of Open Access Journals (Sweden)

    Valentina de Fátima Caleguer

    2007-06-01

    Full Text Available O trabalho teve como objetivo avaliar o efeito sensorial da adição de polpa, carboximetilcelulose (CMC e goma arábica (fibra nos atributos e aceitação de refrescos de laranja. Utilizou-se uma amostra padrão e outras formuladas com polpa, CMC, fibra e todos os ingredientes. Foram realizadas análises físico-químicas (pH, acidez titulável, sólidos solúveis, vitamina C, cor e turbidez, e as amostras também foram caracterizadas pela técnica de Perfil Livre. Na análise descritiva utilizou-se 14 provadores e, para a avaliação dos resultados foi empregada a Análise Procrustes Generalizada. As amostras caracterizadas como diferentes (padrão, CMC, fibra foram submetidas a teste de aceitação. Os refrescos foram caracterizados e separados com base em atributos de aparência (cor laranja e turbidez, aroma (adocicado e laranja, sabor (doce, laranja e ácido e textura (viscosidade. O padrão e a amostra com polpa, que não foram diferenciadas sensorialmente, apresentaram menor intensidade de cor laranja e turbidez, e foram consideradas menos encorpadas e mais ácidas. As amostras com CMC e fibra se diferenciaram do padrão e apresentaram comportamento intermediário. A formulação com todos os ingredientes apresentou características opostas: maior intensidade de cor e turbidez, mais encorpada e menos ácida. As amostras com CMC e fibra foram mais aceitas que o padrão.The aim of this work was to evaluate the sensory effect of adding pulp, carboxymethyl cellulose (CMC and arabic gum (fiber to characteristics and acceptance of powdered orange flavored soft drinks. A standard sample and another formulated with pulp, CMC, fiber with all the ingredients were used. Physicochemical analyses (pH, titratable acidity, soluble solids, vitamin C, color and turbidity were applied and samples were characterized by Free-Choice Profiling. Fourteen panelists were used in the descriptive analysis and the Generalized Procrustes Analysis was applied to

  17. Study on Bleaching Technology of Cotton Fabric with Sodium Percarbonate

    Directory of Open Access Journals (Sweden)

    Li Zhi

    2016-01-01

    Full Text Available 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 percarbonate solution 6 g/ L, bleaching temperature 80°C and bleaching time 60 min.

  18. Pre-treatment and ethanol fermentation potential of olive pulp at different dry matter concentrations

    DEFF Research Database (Denmark)

    Haagensen, Frank Drøscher; Skiadas, Ioannis V.; Gavala, Hariklia N.;

    2009-01-01

    potential of the olive pulp, which is the semi solid residue generated from the two-phase processing of the olives for olive oil production. Wet oxidation and enzymatic hydrolysis have been applied aiming at the enhancement of carbohydrates' bioavailability. Different concentrations of enzymes and enzymatic......, implying that wet oxidation is not a recommended pre-treatment process for olive pulp at the conditions tested. It was also showed that increased dry matter concentration did not have a negative effect on the release of sugars, indicating that the cellulose and xylan content of the olive pulp is relatively...

  19. High-alkali low-temperature polysulfide pulping (HALT) of Scots pine.

    Science.gov (United States)

    Paananen, Markus; Sixta, Herbert

    2015-10-01

    High-alkali low-temperature polysulfide pulping (HALT) was effectively utilised to prevent major polysaccharide losses while maintaining the delignification rate. A yield increase of 6.7 wt% on wood was observed for a HALT pulp compared to a conventionally produced kappa number 60 pulp with comparable viscosity. Approximately 70% of the yield increase was attributed to improved galactoglucomannan preservation and 30% to cellulose. A two-stage oxygen delignification sequence with inter-stage peroxymonosulphuric acid treatment was used to ensure delignification to a bleachable grade. In a comparison to conventional pulp, HALT pulp effectively maintained its yield advantage. Diafiltration trials indicate that purified black liquor can be directly recycled, as large lignin fractions and basically all dissolved polysaccharides were separated from the alkali-rich BL.

  20. Chemical modification of cellulose extracted from sugarcane bagasse: Preparation of hydroxyethyl cellulose

    Directory of Open Access Journals (Sweden)

    E.S. Abdel-Halim

    2014-07-01

    Full Text Available Cellulose was extracted from sugarcane bagasse by alkaline extraction with sodium hydroxide followed by delignification/bleaching using sodium chlorite/hexamethylenetetramine system. Factors affecting extraction process, including sodium hydroxide concentration, hexamethylenetetramine concentration and temperature were studied and optimum conditions for alkaline extraction were found to be boiling finely ground bagasse under reflux in 1 N sodium hydroxide solution and then carrying out the delignification/bleaching treatment at 95 °C using 5 g/l sodium chlorite together with 0.02 g/l hexamethylenetetramine. The extracted cellulose was used in the preparation of hydroxyethyl cellulose through reaction with ethylene oxide in alkaline medium. Factors affecting the hydroxyethylation reaction, like sodium hydroxide concentration during the alkali formation step, ethylene oxide concentration, reaction temperature and reaction duration were studied. Optimum conditions for hydroxyethylation reaction were using 20% NaOH solution and 200% ethylene oxide (based on weight of cellulose, carrying out the reaction at 100 °C for 60 min.

  1. Ethanol/Water Pulps From Sugar Cane Straw and Their Biobleaching With Xylanase from Bacillus pumilus

    Science.gov (United States)

    Moriya, Regina Y.; Gonçalves, Adilson R.; Duarte, Marta C. T.

    The influence of independent variables (temperature and time) on the cooking of sugar cane straw with ethanol/water mixtures was studied to determine operating conditions that obtain pulp with high cellulose contents and a low lignin content. An experimental 22 design was applied for temperatures of 185 and 215°C, and time of 1 and 2.5 h with the ethanol/water mixture concentration and constant straw-to-solvent ratio. The system was scaled-up at 200°C cooking temperature for 2 h with 50% ethanol-water concentration, and 1∶10 (w/v) straw-to-solvent ratio to obtain a pulp with 3.14 cP viscosity, 58.09 kappa-number, and the chemical composition of the pulps were 3.2% pentosan and 31.5% lignin. Xylanase from Bacillus pumilus was then applied at a loading of 5-150 IU/g dry pulp in the sugar cane straw ethanol/water pulp at 50°C for 2 and 20 h. To ethanol/water pulps, the best enzyme dosage was found to be 20 IU/g dry pulp at 20 h, and a high enzyme dosage of 150 IU/g dry pulp did not decrease the kappa-number of the pulp.

  2. Extraction of Cellulose from Kepok Banana Peel (Musa parasidiaca L.) for Adsorption Procion Dye

    OpenAIRE

    Poedji Loekitowati Hariani; Fahma Riyanti; Riski Dita Asmara

    2016-01-01

    The aim of the research was to extract a cellulose from kepok banana peel (Musa parasidiaca L.) and application to removal Procion dye. The extracted cellulose was prepared by dewaxing process to releasing of lignin, bleaching and hemicellulose removal. The cellulose identified by FTIR and SEM-EDS. The efficiency of the cellulose to adsorp Procion dye was evaluated by variation in the initial concentration of dye (5, 10, 15, 20, 25, 30, 35, 40, 45 and 50 mg/L), solution pH (3, 4, 5, 6, 7, 8 a...

  3. The enzymatic hydrolysis of pretreated pulp fibers predominantly involves “peeling/erosion” modes of action

    OpenAIRE

    Arantes, Valdeir; Gourlay, Keith; Saddler, Jack N.

    2014-01-01

    Background There is still considerable debate regarding the actual mechanism by which a “cellulase mixture” deconstructs cellulosic materials, with accessibility to the substrate at the microscopic level being one of the major restrictions that limits fast, complete cellulose hydrolysis. In the work reported here we tried to determine the predominant mode of action, at the fiber level, of how a cellulase mixture deconstructs pretreated softwood and hardwood pulp fibers. Quantitative changes i...

  4. 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.

  5. An in vitro thermal analysis during different light-activated hydrogen peroxide bleaching

    Science.gov (United States)

    Kabbach, W.; Zezell, D. M.; Bandéca, M. C.; Pereira, T. M.; Andrade, M. F.

    2010-09-01

    This study measured the critical temperature reaching time and also the variation of temperature in the surface of the cervical region and within the pulp chamber of human teeth submitted to dental bleaching using 35% hydrogen peroxide gel activated by three different light sources. The samples were randomly divided into 3 groups ( n = 15), according to the catalyst light source: Halogen Light (HL), High Intensity Diode Laser (DL), and Light Emmited Diode (LED). The results of temperature variation were submitted to the analysis of variance and Tukey test with p dental bleaching for a short period of time. The LED source did not heat the target tissues significantly within the parameters used in this study.

  6. Cellulose is not just cellulose

    DEFF Research Database (Denmark)

    Hidayat, Budi Juliman; Felby, Claus; Johansen, Katja S.;

    2012-01-01

    Most secondary plant cell walls contain irregular regions known as dislocations or slip planes. Under industrial biorefining conditions dislocations have recently been shown to play a key role during the initial phase of the enzymatic hydrolysis of cellulose in plant cell walls. In this review we...

  7. Quantification of peroxide ion passage in dentin, enamel, and cementum after internal bleaching with hydrogen peroxide.

    Science.gov (United States)

    Palo, R M; Bonetti-Filho, I; Valera, M C; Camargo, C H R; Camargo, Sea; Moura-Netto, C; Pameijer, C

    2012-01-01

    The aim of this study was to evaluate the amount of peroxide passage from the pulp chamber to the external enamel surface during the internal bleaching technique. Fifty bovine teeth were sectioned transversally 5 mm below the cemento-enamel junction (CEJ), and the remaining part of the root was sealed with a 2-mm layer of glass ionomer cement. The external surface of the samples was coated with nail varnish, with the exception of standardized circular areas (6-mm diameter) located on the enamel, exposed dentin, or cementum surface of the tooth. The teeth were divided into three experimental groups according to exposed areas close to the CEJ and into two control groups (n=10/group), as follows: GE, enamel exposure area; GC, cementum exposed area; GD, dentin exposed area; Negative control, no presence of internal bleaching agent and uncoated surface; and Positive control, pulp chamber filled with bleaching agent and external surface totally coated with nail varnish. The pulp chamber was filled with 35% hydrogen peroxide (Opalescence Endo, Ultradent). Each sample was placed inside of individual flasks with 1000 μL of acetate buffer solution, 2 M (pH 4.5). After seven days, the buffer solution was transferred to a glass tube, in which 100 μL of leuco-crystal violet and 50 μL of 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 Kruskal-Wallis and Dunn-Bonferroni tests (α=0.05). All experimental groups presented passage of peroxide to the external surface that was statistically different from that observed in the control groups. It was verified that the passage of peroxide was higher in GD than in GE (ppermeable than were the dentin and enamel surfaces. PMID:22621165

  8. Application of ultrafiltration in the pulp and paper industry: metals removal and whitewater reuse.

    Science.gov (United States)

    Oliveira, C R; Silva, C M; Milanez, A F

    2007-01-01

    In the pulp and paper industry, the water use minimization is a constant target. One way to reduce water use is to recycle the effluent in a closed-cycle concept. In paper mills, the main source of liquid effluent is the so-called whitewater, which is the excess water, originated from pulp stock dewatering and other fibre contaminated water. This research studied the reuse of paper mill whitewater after membrane ultrafiltration (UF) in the paper machine and in the pulp bleach plant of an integrated mill. Contaminant removal and flux behaviour of the UF system were evaluated. The treatment by ultrafiltration was technically feasible and the treated whitewater had good potential to be reused in some processes in the paper machine. The reuse of ultrafiltered whitewater in the bleaching plant was not recommended because of the high level of soluble calcium present in this stream. Therefore, a combined treatment of the whitewater using the principle of precipitation and ultrafiltration was proposed showing good results and enabling the use of the treated whitewater in the bleach plant.

  9. Dental pulp stem cells

    DEFF Research Database (Denmark)

    Ashri, N. Y.; Ajlan, S. A.; Aldahmash, Abdullah M.

    2015-01-01

    Inflammatory periodontal disease is a major cause of loss of tooth-supporting structures. Novel approaches for regeneration of periodontal apparatus is an area of intensive research. Periodontal tissue engineering implies the use of appropriate regenerative cells, delivered through a suitable...... scaffold, and guided through signaling molecules. Dental pulp stem cells have been used in an increasing number of studies in dental tissue engineering. Those cells show mesenchymal (stromal) stem cell-like properties including self-renewal and multilineage differentiation potentials, aside from...... an updated review on dental pulp stem cells and their applications in periodontal regeneration, in combination with different scaffolds and growth factors....

  10. EFFECT OF SCREW EXTRUSION PRETREATMENT ON PULPS FROM CHEMICAL PULPING

    Directory of Open Access Journals (Sweden)

    Cuihua Dong,

    2012-07-01

    Full Text Available The effect of compressive pretreatment before chemical pulping on the properties of poplar kraft and soda-AQ pulp was evaluated. Compressive pretreatment not only resulted in the dissolution of hemicellulose, but also leached extractives. Pulps made from compressive pretreated wood chips required lower beating energy than the untreated pulps to achieve the same beating degree of 45°SR, and the brightness of the handsheets was improved by 2% ISO. Compressive pretreatment allowed for efficient delignification and saved about 6% alkali consumption to achieve similar pulp screen yield. Furthermore, a higher content of fines and slightly lower mechanical properties were observed after the compressive treatment.

  11. Overview of Cellulose Nanomaterials, Their Capabilities and Applications

    Science.gov (United States)

    Moon, Robert J.; Schueneman, Gregory T.; Simonsen, John

    2016-09-01

    Cellulose nanomaterials (CNs) are a new class of cellulose particles with properties and functionalities distinct from molecular cellulose and wood pulp, and as a result, they are being developed for applications that were once thought impossible for cellulosic materials. Momentum is growing in CN research and development, and commercialization in this field is happening because of the unique combination of characteristics (e.g., high mechanical properties, sustainability, and large-scale production potential) and utility across a broad spectrum of material applications (e.g. as an additive, self-sustaining structures, and template structures) that CNs offer. Despite the challenges typical for materials development, CN and near-CN production is ramping up with pilot scale to industry demonstration trials, and the first commercial products are starting to hit the marketplace. This review provides a broad overview of CNs and their capabilities that are enabling new application areas for cellulose-based materials.

  12. Nanofibrillated cellulose as an additive in papermaking process: A review.

    Science.gov (United States)

    Boufi, Sami; González, Israel; Delgado-Aguilar, Marc; Tarrès, Quim; Pèlach, M Àngels; Mutjé, Pere

    2016-12-10

    During the last two decades, cellulose nanofibres (CNF) have emerged as a promising, sustainable reinforcement with outstanding potential in material sciences. Though application of CNF in papermaking is recent, it is expected to find implementation in the near future to give a broader commercial market to this type of cellulose. The present review highlights recent progress in the field of the application of cellulose nanofibres as additives in papermaking. The effect of CNF addition on the wet end process is analysed according to the type of pulp used for papermaking. According to the literature consulted, improvement in paper's overall properties after CNF addition depended not only on the type and amount of CNF applied, but also in the pulp's origin and treatment. Bulk and surface application of CNF also presented significant differences regarding paper's final properties. This review also revises the mechanisms behind CNF reinforcing effect on paper and the effect of chemically modified CNF as additives. PMID:27577906

  13. Wood Pulp Properties of Normal Wood and Tension Wood of Populus×euramericana (Dode) Guiner CL.‘zhong-lin 46 ’%中林-46杨正常木与应拉木制浆性能的比较

    Institute of Scientific and Technical Information of China (English)

    陆雅婕; 丁小龙; 高文丽; 付建虎; 高慧

    2014-01-01

    With normal wood and tension wood of Populus×euramericana (Dode) Guiner CL.‘zhonglin 46’, the experiment was conducted to study the effects of fiber morphological properties, chemical compositions, pulping, and bleaching.The width of cell wall, runkel ratio, ray proportion, and fiber proportion of tension wood are higher than those of normal wood.How-ever, the fibrous length-width ratio, lumen diameter and vessel proportion of tension wood are lower than those of normal wood.In the chemical composition, the cellulose content, benzene-alcohol extractives, 1%of NaOH extractives and ash of tension woodare higher than those of normal wood.The hemicellulose , holocellulose and lignin of tension wood are less than those of normal wood.In pulping and bleaching for normal wood and tensionwood , the tension wood has higher pul-ping yield, lower Kappa number, and lower brightness of pulp than those of normal wood.%以中林-46杨正常木与应拉木为研究对象,分析比较其在纤维形态、化学组成和制浆漂白上的差异。结果表明在纤维形态上应拉木的双壁厚、壁腔比、木射线比量和纤维比量均高于正常木,而正常木的纤维长宽比、胞腔径、导管比量均大于应拉木;在化学组成上,应拉木的纤维素、苯醇抽出物、1%NaOH抽出物、灰分质量分数均高于正常木,而正常木的半纤维素、综纤维素、木质素质量分数均高于应拉木;在制浆漂白上,应拉木比正常木得率高,卡伯值和白度较低。

  14. On luminescence bleaching of tidal channel sediments

    DEFF Research Database (Denmark)

    Fruergaard, Mikkel; Pejrup, Morten; Murray, Andrew S.;

    2015-01-01

    We investigate the processes responsible for bleaching of the quartz OSL signal from tidal channel sediment. Tidal dynamics are expected to play an important role for complete bleaching of tidal sediments. However, no studies have examined the amount of reworking occurring in tidal channels and o...

  15. Infection and Pulp Regeneration

    Directory of Open Access Journals (Sweden)

    Sahng G. Kim

    2016-03-01

    Full Text Available The regeneration of the pulp-dentin complex has been a great challenge to both scientists and clinicians. Previous work has shown that the presence of prior infection may influence the characteristics of tissues formed in the root canal space after regenerative endodontic treatment. The formation of ectopic tissues such as periodontal ligament, bone, and cementum has been observed in the root canal space of immature necrotic teeth with apical periodontitis, while the regeneration of dentin and pulp has been identified in previously non-infected teeth. The current regenerative endodontic therapy utilizes disinfection protocols, which heavily rely on chemical irrigation using conventional disinfectants. From a microbiological point of view, the current protocols may not allow a sufficiently clean root canal microenvironment, which is critical for dentin and pulp regeneration. In this article, the significance of root canal disinfection in regenerating the pulp-dentin complex, the limitations of the current regenerative endodontic disinfection protocols, and advanced disinfection techniques designed to reduce the microorganisms and biofilms in chronic infection are discussed.

  16. WATER RETENTION VALUE MEASUREMENTS OF CELLULOSIC MATERIALS USING A CENTRIFUGE TECHNIQUE

    Directory of Open Access Journals (Sweden)

    Jinxin Wang

    2010-07-01

    Full Text Available A centrifugal method has been modified and applied to the assessment of water retention value (WRV in cellulosic materials. Microcrystalline cellulose (MCC, small particles/fibrils isolated from MCC using high-pressure homogenizer, and pulp fibers saturated in water were centrifuged at different speeds and times with filter paper and/or a membrane acting as the filter in the WRV measurement setup. As centrifugal speed, time, and filter pore-size increased, lower WRVs were obtained. Smaller MCC particles/fibrils retained more water than the as-received MCC and pulp fibers. The results are useful for WRV measurements of cellulosic materials, especially for microfibrillated cellulose and small cellulosic fibrils.

  17. Bleaching in vital teeth: a literary review

    Directory of Open Access Journals (Sweden)

    Felipe Fagundes Soares

    2008-01-01

    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.

  18. Hydrogen production from carrot pulp by the extreme thermophiles Caldicellulosiruptor saccharolyticus and Thermotoga neapolitana

    Energy Technology Data Exchange (ETDEWEB)

    Vrije, Truus de; Budde, Miriam A.W.; Lips, Steef J.; Bakker, Robert R.; Mars, Astrid E.; Claassen, Pieternel A.M. [Wageningen UR, Food and Biobased Research, P.O. Box 17, 6700 AA Wageningen (Netherlands)

    2010-12-15

    Hydrogen was produced from carrot pulp hydrolysate, untreated carrot pulp and (mixtures of) glucose and fructose by the extreme thermophiles Caldicellulosiruptor saccharolyticus and Thermotoga neapolitana in pH-controlled bioreactors. Carrot pulp hydrolysate was obtained after enzymatic hydrolysis of the polysaccharide fraction in carrot pulp. The main sugars in the hydrolysate were glucose, fructose, and sucrose. In fermentations with glucose hydrogen yields and productivities were similar for both strains. With fructose the hydrogen yield of C. saccharolyticus was reduced which might be related to uptake of glucose and fructose by different types of transport systems. With T. neapolitana the fructose consumption rate and consequently the hydrogen productivity were low. The hydrogen yields of both thermophiles were 2.7-2.8 mol H{sub 2}/mol hexose with 10 g/L sugars from carrot pulp hydrolysate. With 20 g/L sugars the yield of T. neapolitana was 2.4 mol H{sub 2}/mol hexose while the yield of C. saccharolyticus was reduced to 1.3 mol H{sub 2}/mol hexose due to high lactate production in the stationary growth phase. C. saccharolyticus was able to grow on carrot pulp and utilized soluble sugars and, after adaptation, pectin and some (hemi)cellulose. No growth was observed with T. neapolitana when using carrot pulp in agitated fermentations. Enzymatic hydrolysis of the polysaccharide fraction prior to fermentation increased the hydrogen yield with almost 10% to 2.3 g/kg of hydrolyzed carrot pulp. (author)

  19. [Gingival bleaching: teaching and ethnocentrism].

    Science.gov (United States)

    Bolla, Edson Daruich; Goldenberg, Paulete

    2010-06-01

    The aim of this study was to identify buccal/gingival cosmetic dentistry patterns subjacent to formation and professional practice of the dental surgeon from the ethnocentrism point of view. This is an exploratory study with a qualitative approach based on the thematic analysis. Initially a documental analysis was carried out. Thereafter, dental surgeons were interviewed and semi-structured questions were applied. In the Periodontal teaching field, this study showed that the presence of racial melanosis is omitted or treated as an alteration in the normality patterns and it is considered anti-aesthetic. All the interviewers learnt how to practice gingival bleaching in the post-graduation courses, they were all encouraged to offer this cosmetic dentistry procedure with the opportunity of obtaining a beautiful and healthy smile, thus assuring the belief of the Caucasian racial aesthetic superiority. This study make us think that the offer of gingival bleaching is oriented by the Caucasian pattern of beauty evidencing the ethnocentric character of this procedure. PMID:20640340

  20. RELATIVE IMPORTANCE OF WOOD DENSITY AND CARBOHYDRATE CONTENT ON PULPING YIELD AND PRODUCT QUALITY

    Institute of Scientific and Technical Information of China (English)

    Colodette,J.L.; Mokfienski; Gomide; J.L.; Oliveiral; R.C.

    2004-01-01

    The purpose of this study was to evaluate basicdensity, chemical composition and fiber dimensionsof ten Eucalyptus sp wood samples and verify theimpact of this set of parameters and theii"combination on the Kraft pulping process yield andon bleached pulp quality. Ten eucalypt woods ofdifferent species, with basic densities varying from365 to 544 kg/m3 and total wood carbohydratecontents varying from 70.0 to 74.5% , weretransformed into kraft pulp of kappa number 17-18and bleached to 90% ISO brightness by the sequenceOD (PO)D. Wood basic density showed strongercorrelations with fiber dimensions, pulping yield andpulp quality than did chemical composition. Lighterwoods resulted in higher yields. However, woodspecific consumption was lower for denser woods,even though these demanded more drastic pulpingconditions to achieve a given kappa number. Thepulp quality results suggest that lower density woodsshould be directed towards fabrication of refinedpaper (printing and writing grades) while the denserwoods be directed to the sanitary papers segment(tissue grades).

  1. A CHEMICAL PROCESS FOR PREPARING CELLULOSIC FIBERS HIERARCHICALLY FROM KENAF BAST FIBERS

    Directory of Open Access Journals (Sweden)

    Jinshu Shi

    2011-02-01

    Full Text Available The objective of this research was to evaluate an all-chemical process to prepare nano-scale to macro-scale cellulosic fibers from kenaf bast fibers, for polymer composite reinforcement. The procedure used in this all-chemical process included alkaline retting to obtain single cellulosic retted fiber, bleaching treatment to obtain delignified bleached fiber, and acidic hydrolysis to obtain both pure-cellulose microfiber and cellulose nanowhisker (CNW. At each step of this chemical process, the resultant fibers were characterized for crystallinity using X-ray diffraction (XRD, for functional groups using the Fourier Transform Infrared spectroscopy (FTIR, and for surface morphology using both the scanning electron microscopy (SEM and transmission electron microscopy (TEM. The chemical components of the different scale fibers were analyzed. Based on the raw kenaf bast fibers, the yields of retted fibers and bleached fibers were 44.6% and 41.4%. The yield of the pure cellulose microfibers was 26.3%. The yield of CNWs was 10.4%, where about 22.6% α-cellulose had been converted into CNWs. The fiber crystallinity increased as the scale of the fiber decreased, from 49.9% (retted single fibers to 83.9% (CNWs. The CNWs had fiber lengths of 100 nm to 1400 nm, diameters of 7 to 84 nm, and aspect ratios of 10 to 50. The incorporation of 9% (wt% CNWs in polyvinyl alcohol (PVA composites increased the tensile strength by 46%.

  2. Perubahan NIlai pH Media Cair Daerah Permukaan Leher Gigi Pada Perawatan Bleaching Intra Korona

    Directory of Open Access Journals (Sweden)

    Kamizar Kamizar

    2015-10-01

    Full Text Available Intra coronal bleaching treatment can cause penetration of bleaching materials into the cervical teeth surface and due to this penetration the pH range would change around these area. From this point the research started by arranging 3 types of bleaching materials i.e. mixture of sodium perborat with water, sodium perborat with H2O2 3% and sodium perborat with H2O2 30%. These bleaching component were conditioned into the pulp 2 mm under cemento enamel junction on the trial tooth whose roots had been filled in, after that it was covered up with zinc phosphat cement and above this paraffin wax and nail. The removed tooth was soaked in a aquabides bottle and pH value was measured from the first day, third and seventh. Result showed that there was a change of pH in the aquabidest. The change appeared firstly on the first day with various levels on each group. Sod. Perborat + H2O2 3% to 7,84 and with water 8,015. As a matter of fact on the third day the change happened to sod. Perborat with water 8,037 and 8,298 with H2O2 3% 8,732 and 8,750. While sod. perborat with H2O2 30% was felt down its concentration into 8,847 and 8,827. As a result the change aquabidest pH was interfered or depended on the mixture of the bleaching materials itself such as; so. Perborat with water=10,15 ; sod. perborat with H2O2 3%= 9,10; sod. perborat with H2O2 30%= 7,60. pH value sod. perborat with water on the seventh day showed up its raising action though it's still below the rest two other groups' concentration pH levels.

  3. EFFECT OF XYLANASE TREATMENT ON DEWATERING PROPERTIES OF BIRCH KRAFT PULP

    Directory of Open Access Journals (Sweden)

    Minna Marianne Blomstedt

    2010-04-01

    Full Text Available In this study it was shown that the enzymatic removal of xylan from ECF-bleached birch kraft pulp enhances the water removal from the pulp, especially in the late stages of pulp drying. The effect of xylanase treatments on dewatering was clarified by using a moving belt former (MBF, a press simulator (MTS, and an IR-drying equipment, to simulate and to measure dewatering properties on wire, press and drying sections of a paper machine. The xylanase treatment slightly increased the pulp freeness indicating improved pulp drainage properties. At the moving belt former, however, no significant changes that would indicate enhanced dewatering in forming were observed. The xylanase treatments slightly enhanced the dewatering in wet pressing and furthermore, at the thermal drying the xylanase treatment had a positive effect on the dry solid content (DSC development, and time to reach the 95% dry solids content was reduced by up to 15%. This was also confirmed by the decrease in the fiber saturation point (FSP values and the amount of bulk water. Our results indicate that the xylanase treatment affected the water-binding xylan in the fiber cell wall, yielding enhanced dewatering properties, without deteriorating the pulp and paper properties.

  4. 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

  5. SODA-AQ PULPING OF PAULOWNIA WOOD AFTER HYDROLYSIS TREATMENT

    Directory of Open Access Journals (Sweden)

    Juan Carlos García

    2011-04-01

    Full Text Available A trihybrid clone of Paulownia fortunei x tormentosa x elongata was used for pulp and paper production using the soda-anthraquinone (AQ process, comparing the results with those from Paulownia fortunei. An autohydrolysis process had been previously carried out on this raw material. A composite central experimental design and a multiple regression were used for modeling and optimizing the process. A valuable liquid phase could be obtained from the autohydrolysis process of Paulownia, trying to minimize cellulose degradation for pulp and paper production. A compromise to maximize the glucan and minimize the xylan contents in the postautohydrolysis solid phase could be achieved at 187.5ºC and 15 minutes. A suitable cellulosic pulp with kappa number ranging from 12.2 to 69.2 and ISO brightness from 18.2 to 30.6% presented better results than those from other studies. Regarding handsheets physical properties (tensile index 37.3 N•m/g and viscosity (848 cm3/g, significant improvements could be obtained when compared with previous results of a similar process using Paulownia fortunei or Paulownia elongata.

  6. A NEW METHOD FOR MAKING CELLULOSE AND LIGNIN FROM BAMBOO BY HIGH BOILING SOLVENT

    Institute of Scientific and Technical Information of China (English)

    XiansuCHENG; WeijianCHEN; YunpingCHEN; HuashuFANG; MianjunLI; YuexianCHEN

    2004-01-01

    In order to establish a new method for making cellulose and lignin from bamboo, a high boiling solvent (HBS) pulping process with aqueous solvcnt of 1,4-butanediol was investigated. Bamboo chips were pulped with 70~90% aqueous solution of 1. 4-butanediol containing a small amount of catalyst at 180~200℃ for 30~90 min. HBS bamboo cellulose is suitable for making paper. Water-insoluble HBS lignin was separated from the liquor reaction mixture by water precipitation. Recovery high boiling solvents (RHBS) is able to recycle as a pulping solvent indicating that the HBS method is a pulping process of bamboo with saving energy, saving resources and non-pollution. HBS lignin has better chemical activity and lower ash content than lignin sulfonate.

  7. A NEW METHOD FOR MAKING CELLULOSE AND LIGNIN FROM BAMBOO BY HIGH BOILING SOLVENT

    Institute of Scientific and Technical Information of China (English)

    Xiansu CHENG; Weijian CHEN; Yunping CHEN; Huashu FANG; Mianjun LI; Yuexian CHEN

    2004-01-01

    In order to establish a new method for making cellulose and lignin from bamboo, a high boiling solvent (HBS) pulping process with aqueous solvent of 1,4-butanediol was investigated. Bamboo chips were pulped with 70~90% aqueous solution of 1,4-butanediol containing a small amount of catalyst at 180~200℃ for 30-90 min.. HBS bamboo cellulose is suitable for making paper. Water-insoluble HBS lignin was separated from the liquor reaction mixture by water precipitation. Recovery high boiling solvents (RHBS) is able to recycle as a pulping solvent indicating that the HBS method is a pulping process of bamboo with saving energy, saving resources and non-pollution. HBS lignin has better chemical activity and lower ash content than lignin sulfonate.

  8. Pulping performance of transgenic poplar with depressed Caffeoyl-CoA O-methyltransferase

    Institute of Scientific and Technical Information of China (English)

    WEI JianHua; WANG YanZhen; WANG HongZhi; LI RuiFen; LIN Nan; MA RongCai; QU LeQing; SONG YanRu

    2008-01-01

    This paper evaluated pulping performance of 3-year-old field-grown transgenic poplar (Populus tremula × Populus alba). The transgenic poplar with anti-sense CCoAOMT had an about 13% decreased lignin content, in which a slight increment was found in S/G ratio. Chemical analysis showed that the trans-genic poplar had significantly less benezene-ethanol extractive than that of control wood, but no sig-nificant differences were found in contents of ash, cold water extractive, hot water extractive, 1% NaOH extractive, holocellulose, pentosans and cellulose. Fiber assay demonstrated that down-regulation of CCoAOMTexpression improved the fiber quality in transgenic poplar. Kraft pulping showed that lower lignin in transgenic poplar led to remarkable improved pulp quality and increased pulp yield.

  9. 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.

  10. Oxidized Cellulose with Different Carboxyl Content: Structure and Properties before and after Beating

    Science.gov (United States)

    Vendula, Hejlová; Miloslav, Milichovský

    Our recent studies concentrated in investigating influence of beating oxidized cellulose, with different carboxyl content, on changing their basic properties (degree of polymerization, WRV - water resistant value and X-ray diffraction). Cellulose samples of oxidized cellulose were beated by toroidal beating machine. Cellulose consists of both amorphous and crystalline regions. Cellulose consists of linear chains of poly[ß-1,4-D- anhydroglucopyranose] (C6nH10n + 2O5n + 1 (n = degree of polymerization of glucose)), which crystallize through hydrogen bonding between the chains and has cellobiose as repeat unit. Oxidized cellulose is preparing by oxidation of cellulose in the C6 position of the glucopyranose units to carboxylic group (-COOH) and polyanhydroglukuronic acid (PAGA) is arised. An other option is oxidation with sodium hypochlorite with catalytic amounts of sodium bromide and 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) under various conditions. Beating and refining or mechanical treatment of fibers in water is an important step in using pulps for papermaking. It is an energy intensive process. The purpose of the treatment is to modify fiber properties to obtain the most desirable paper machine runnability and product properties. End of beating pulps was characterized by position, when all beated pulps under mixture passed through of riddle (about sizes mesh of 50). During beating of samples about different ratio of oxidation it was found, that samples with higher contents of COOH groups in starting pulp are characterized by a significantly lower specific beating energy consumption needed to achieving the same sizes of particles. X-ray analyse shows that for non-beated oxidized cellulose was perceptible high share amorphous contents compared with beated oxidized cellulose.

  11. Synthesis of polycaprolactone-grafted microfibrillated cellulose for use in novel bionanocomposites--influence of the graft length on the mechanical properties.

    Science.gov (United States)

    Lönnberg, Hanna; Larsson, Karolina; Lindström, Tom; Hult, Anders; Malmström, Eva

    2011-05-01

    In the present work, microfibrillated cellulose (MFC) made from bleached sulfite softwood dissolving pulp was utilized to reinforce a poly(ε-caprolactone) (PCL) biopolymer matrix. To improve the dispersibility of the hydrophilic MFC in the nonpolar matrix and the interfacial adhesion in the composite material, we covalently grafted the MFC with PCL via ring-opening polymerization (ROP) of ε-caprolactone (ε-CL). To be able to investigate the effect of the PCL graft length on the mechanical properties of the composite material, we performed ROP to different molecular weights of the grafts. Bionanocomposites containing 0, 3, and 10 wt % MFC were prepared via hot pressing using both unmodified and PCL grafted MFC (MFC-g-PCL) as reinforcement. PCL grafting resulted in improved dispersion of the MFC in a nonpolar solvent and in the PCL matrix. The mechanical testing of the biocomposites showed an improvement in the mechanical properties for the PCL grafted MFC in comparison to ungrafted MFC. It was also shown that there was an impact on the mechanical properties with respect to the PCL graft lengths, and the strongest biocomposites were obtained after reinforcement with MFC grafted with the longest PCL graft length.

  12. 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.

  13. Non-wood fibre production of microcrystalline cellulose from Sorghum caudatum: Characterisation and tableting properties

    Directory of Open Access Journals (Sweden)

    Ohwoavworhua F

    2010-01-01

    Full Text Available The microcrystalline cellulose is an important ingredient in pharmaceutical, food, cosmetic and other industries. In this study, the microcrystalline cellulose, obtained from the stalk of Sorghum caudatum was evaluated for its physical and tableting characteristics with a view to assessing its usefulness in pharmaceutical tableting. The microcrystalline cellulose, obtained from the stalk of Sorghum caudatum, obtained by sodium hydroxide delignification followed by sodium hypochlorite bleaching and acid hydrolysis was examined for its physicochemical and tableting properties in comparison with those of the well-known commercial microcrystalline cellulose grade, Avicel PH 101. The extraction yield of this microcrystalline cellulose, obtained from the stalk of Sorghum caudatum was approximately 19%. The cellulose material was composed of irregularly shaped fibrous cellulose particles and had a moisture content of 6.2% and total ash of 0.28%. The true density was 1.46. The flow indices showed that the microcrystalline cellulose, obtained from the stalk of Sorghum caudatum flowed poorly. The hydration, swelling and moisture sorption capacities were 3.9, 85 and 24%, respectively. Tablets resulting from these cellulose materials were found to be without surface defects, sufficiently hard and having disintegration time within 15 min. The study revealed that the microcrystalline cellulose, obtained from the stalk of Sorghum caudatum compares favourably with Avicel PH 101 and conformed to official requirement specified in the British Pharmacopoeia 1993 for microcrystalline cellulose.

  14. Modeling Reef Hydrodynamics to Predict Coral Bleaching

    Science.gov (United States)

    Bird, James; Steinberg, Craig; Hardy, Tom

    2005-11-01

    The aim of this study is to use environmental physics to predict water temperatures around and within coral reefs. Anomalously warm water is the leading cause for mass coral bleaching; thus a clearer understanding of the oceanographic mechanisms that control reef water temperatures will enable better reef management. In March 1998 a major coral bleaching event occurred at Scott Reef, a 40 km-wide lagoon 300 km off the northwest coast of Australia. Meteorological and coral cover observations were collected before, during, and after the event. In this study, two hydrodynamic models are applied to Scott Reef and validated against oceanographic data collected between March and June 2003. The models are then used to hindcast the reef hydrodynamics that led up to the 1998 bleaching event. Results show a positive correlation between poorly mixed regions and bleaching severity.

  15. COMPARATIVE STUDY OF PULP AND PAPER PROPERTIES OF CANOLA STALKS PREPARED BY USING DIMETHYL FORMAMIDE OR DIETHYLENE GLYCOL

    Directory of Open Access Journals (Sweden)

    Mohammad. H. Ekhtera

    2009-02-01

    Full Text Available Comparision between pulping of canola stalks with dimethyl formamide and diethylene glycol was studied in order to investigate the effects of cooking temperature (190˚C, 210˚C, and 230˚C, cooking time (120 min, 150 min, and 180 min and dimethyl formamide or diethylene glycol (50%, 60%, and 70% on the properties of pulp and paper. SCAN viscosity was applied to estimate the extent of cellulose degradation. Responses of pulp and handsheet properties to the process were analyzed using statistical software (MINITAB 15. The results showed that DMF pulp of canola was better than DEG pulp of Canola under the same conditions of cooking and organosolv ratio. In DMF pulping and DEG pulping, cooking temperature is a significant factor affecting paper properties. Analysis of results revealed that DMF pulp canola obtained at 230 °C, 180 min, and 70% DMF had a low kappa number (25 , indicating that the desired properties of the final product dictated the optimized pulping conditions.

  16. The walking bleach procedure: an in vitro study to measure microleakage of five temporary sealing agents.

    Science.gov (United States)

    Hosoya, N; Cox, C F; Arai, T; Nakamura, J

    2000-12-01

    The purpose of this study was to compare the in vitro sealing capacity of five materials, each used as a temporary sealing agent for the walking bleach technique. All teeth received traditional biomechanical root canal instrumentation, after which the walking bleach agent was placed in the pulp chamber space. The occlusal access was sealed with one of five temporary materials: two hydraulic filling materials, a photoactivated resin composite, a zinc oxide-eugenol cement, and a zinc oxide phosphate cement with/without the placement of a piece of rubber sheet that was placed as a barrier to isolate filling material from the bleaching agent. All teeth were stored in a 1% solution of Alcian blue with thermal cycling stress. After 1 wk, they were sectioned longitudinally, and ranked by graded scores of 0 to 3, according to the degree of the dye penetration. Significantly less dye microleakage was observed in the two hydraulic materials than in the photoactivated resin. Both zinc oxide-eugenol and zinc phosphate cements showed a considerable amount of microleakage. There were no significant differences between the groups with and without a rubber sheet. Our data demonstrate that hydraulic filling materials provide the most favorable cavosurface seal when they are firmly packed into the cavity space to prevent microleakage.

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

    International Nuclear Information System (INIS)

    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 107R, but there was a slight deterioration up to 106R. (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. Magnetic and electric field alignments of cellulose chains for electro-active paper actuator

    Science.gov (United States)

    Yun, Sungryul; Chen, Yi; Lee, Sang Woo; Kim, Jaehwan; Kim, Heung Soo

    2008-03-01

    To improve the piezoelectricity of cellulose electro-active paper (EAPap), electrical field and magnetic field alignments were investigated. EAPap is made with cellulose by dissolving cotton pulp and regenerating cellulose with aligned cellulose fibers. EAPap made with cellulose has piezoelectric property due to its structural crystallinity. Noncentro-symmetric crystal structure of EAPap, which is mostly cellulose II, can exhibit piezoelectricity. However, EAPap has ordered crystal parts as well as disordered parts of cellulose. Thus, well alignment of cellulose chains in EAPap is important to improve its piezoelectricity. In this paper, uniaxial alignments of cellulose chains were investigated by applying electric field and magnetic field. As exposing different fields to EAPap samples, the changed characteristics were analyzed by X-Ray diffractometer (XRD) and Scanning electron microscopy (SEM). Finally, the piezoelectricity of EAPap samples was evaluated by comparing their piezoelectric charge constant [d 31]. As increasing applied electric field up to 40V/mm, d 31 value was gradually improved due to increased cellulose crystallinity as well as alignment of cellulose chains. Also the alignment of cellulose chains was improved with increasing the exposing time to magnetic field (5.3T) and well alignment was achieved by exposing EAPap sample on the magnetic field for 180min.

  19. Enzymic hydrolysis of cellulosic substances by the crude cellulase from Aspergillus aculeatus

    Energy Technology Data Exchange (ETDEWEB)

    Sakamoto, R.; Hayashi, H.; Moriyama, K.; Arai, M.; Murao, S.

    1982-01-01

    The activity of crude cellulase powder from A. aculeatus F-50 was investigated on rice straw, citrus peel, and kraft pulp. After treatment of straw with 1% NaOH for 3 h, cellulase at 37 degrees for 3 days produced 85% solution, with a yield of 8% reducing sugar, which consisted of glucose and xylose. When cellulase from Trichoderma reesei was combined with A. aculeatus cellulase, a yield of 8% reducing sugars was reached in 1 day. Solubilization of orange peel was greater than 70% in 12 hours and of bleached kraft pulp, 73% in 3 days by A. aculeatus cellulase. The only reducing sugar produced was glucose.

  20. 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

  1. Accelerated coffee pulp composting.

    Science.gov (United States)

    Sánchez, G; Olguín, E J; Mercado, G

    1999-02-01

    The effect of two abundant, easily available and very low-cost agro-industrial organic residues, i.e., filter cake from the sugar industry and poultry litter, on the composting stabilization time of coffee pulp and on the quality of the produced compost, was evaluated. Piles of one cubic meter were built and monitored within the facilities of a coffee processing plant in the Coatepec region of the State of Veracruz, Mexico. Manual aeration was carried out once a week. A longer thermophilic period (28 days) and a much lower C/N ratio (in the range of 6.9-9.1) were observed in the piles containing the amendments, as compared to the control pile containing only coffee pulp (14 days and a C/N ratio of 14.4, respectively). The maximum assimilation rate of the reducing sugars was 1.6 g kg-1 d-1 (from 7.5 to 5.3%) during the first two weeks when accelerators were present in the proportion of 20% filter cake plus 20% poultry litter, while they accumulated at a rate of 1.2 g kg-1 d-1 (from 7.4 to 9.13%) during the same period in the control pile. The best combination of amendments was 30% filter cake with 20% poultry litter, resulting in a final nitrogen content as high as 4.81%. The second best combination was 20% filter cake with 10% poultry litter, resulting in a compost which also contained a high level of total nitrogen (4.54%). It was concluded that the use of these two residues enhanced the composting process of coffee pulp, promoting a shorter stabilization period and yielding a higher quality of compost.

  2. New method of laser doppler flowmetry signal processing in pulp vitality evaluation after teeth cosmetic treatment

    Science.gov (United States)

    Todea, Carmen; Sarpe, Amalia; Vitez, Bogdan; Draganescu, Gheorghe

    2014-01-01

    The present study aims to assess the pulp vitality before and after different tooth bleaching procedures, in order to determine the changes in pulpal microcirculation and whether they are reversible or not. Twelve volunteers were included in this study. For each volunteer, the pulpal blood flow of maxillary teeth was assessed prior to treatment using Laser Doppler Flowmetry. The "in office" bleaching technique was used 6 anterior teeth, with two different gels, a conventional one chemically activated (Group I 3teeth) and another one activated using Nd:YAG laser (Group II-3 teeth). The bleaching agents were applied on counterpart teeth and, after obtaining a esthetic results for each tooth, the pulpal blood flow was assessed using Laser Doppler Flowmetry immediately after treatment and then after one day and one week. All data were collected and statistically analyzed. Immediately after treatment, the assessment showed an increase of pulpal blood flow, for both study groups, but higher in Group I as compared to Group II (ptreatment method, which does not lead to irreversible damage to the dental pulp, when used correctly.

  3. 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

  4. WATER RETENTION VALUE MEASUREMENTS OF CELLULOSIC MATERIALS USING A CENTRIFUGE TECHNIQUE

    OpenAIRE

    Jinxin Wang; Qingzheng Cheng; Joseph McNeel; Peter Jacobson

    2010-01-01

    A centrifugal method has been modified and applied to the assessment of water retention value (WRV) in cellulosic materials. Microcrystalline cellulose (MCC), small particles/fibrils isolated from MCC using high-pressure homogenizer, and pulp fibers saturated in water were centrifuged at different speeds and times with filter paper and/or a membrane acting as the filter in the WRV measurement setup. As centrifugal speed, time, and filter pore-size increased, lower WRVs were obtained. Smaller ...

  5. Nanomanufacturing metrology for cellulosic nanomaterials: an update

    Science.gov (United States)

    Postek, Michael T.

    2014-08-01

    The development of the metrology and standards for advanced manufacturing of cellulosic nanomaterials (or basically, wood-based nanotechnology) is imperative to the success of this rising economic sector. Wood-based nanotechnology is a revolutionary technology that will create new jobs and strengthen America's forest-based economy through industrial development and expansion. It allows this, previously perceived, low-tech industry to leap-frog directly into high-tech products and processes and thus improves its current economic slump. Recent global investments in nanotechnology programs have led to a deeper appreciation of the high performance nature of cellulose nanomaterials. Cellulose, manufactured to the smallest possible-size ( 2 nm x 100 nm), is a high-value material that enables products to be lighter and stronger; have less embodied energy; utilize no catalysts in the manufacturing, are biologically compatible and, come from a readily renewable resource. In addition to the potential for a dramatic impact on the national economy - estimated to be as much as $250 billion worldwide by 2020 - cellulose-based nanotechnology creates a pathway for expanded and new markets utilizing these renewable materials. The installed capacity associated with the US pulp and paper industry represents an opportunity, with investment, to rapidly move to large scale production of nano-based materials. However, effective imaging, characterization and fundamental measurement science for process control and characterization are lacking at the present time. This talk will discuss some of these needed measurements and potential solutions.

  6. PRODUCTION AND CHARACTERIZATION OF ECONOMICAL BACTERIAL CELLULOSE

    Directory of Open Access Journals (Sweden)

    Houssni El-Saied

    2008-11-01

    Full Text Available The present study investigates the economical production of bacterial cellulose (BC by Gluconacetobacter subsp. Xylinus (ATCC 10245 in 250 ml Erlenmeyer flasks cultivated under static conditions. The fermentation media used contained food industrial by-product liquors, such as black strap molasses solution and corn steep liquor (CSL, which represents some of the most economical carbon and nitrogen sources. However, because of the presence of undesirable components in molasses (such as coloring substances, heavy metals, and other compounds that may act as inhibitors, and in order to eliminate them, crude molasses has been treated with an acid, as an attempt to increase BC productivity. The amount of BC produced using these carbon and nitrogen sources was determined and compared to that produced using previously reported fermentation media. The characterizations of the bacterial cellulose (BC pellicles obtained using either conventional or by-product media were studied by thermal and spectral techniques and compared to those of plant-derived cellulose such as cotton linter, viscose pulp, and microcrystalline cellulose.

  7. Use of Cellulose-Containing Fillers in Composites with Polypropylene

    Directory of Open Access Journals (Sweden)

    Marianna LAKA

    2011-07-01

    Full Text Available The composites, containing recycled polypropylene and fillers, obtained from different lignocellulosics by the thermocatalytic destruction method, were investigated. Birch sawdust, newsprint wastes, cotton residues and wood bleached sulphate pulp were used as raw materials for obtaining fillers. The indices of mechanical properties (tensile strength, modulus of elasticity, deformation at break, shear modulus, toughness, twisting moment of the composites' samples were determined. It has been found that the obtained composites have relatively good mechanical properties. Better results were obtained, using fillers from sawdust and wood pulp. After treating the fillers with rapeseed oil, their water vapour sorption and water retention value (WRV decreased. In this case, the strength of the composites was higher.http://dx.doi.org/10.5755/j01.ms.17.2.484

  8. Clinical comparison between the bleaching efficacy of light-emitting diode and diode laser with sodium perborate.

    Science.gov (United States)

    Koçak, Sibel; Koçak, Mustafa Murat; Sağlam, Baran Can

    2014-04-01

    The aim of this clinical study was to test the efficacy of a light-emitting diode (LED) light and a diode laser, when bleaching with sodium perborate. Thirty volunteers were selected to participate in the study. The patients were randomly divided into two groups. The initial colour of each tooth to be bleached was quantified with a spectrophotometer. In group A, sodium perborate and distilled water were mixed and placed into the pulp chamber, and the LED light was source applied. In group B, the same mixture was used, and the 810 nm diode laser was applied. The final colour of each tooth was quantified with the same spectrophotometer. Initial and final spectrophotometer values were recorded. Mann-Whitney U-test and Wicoxon tests were used to test differences between both groups. Both devices successfully whitened the teeth. No statistical difference was found between the efficacy of the LED light and the diode laser.

  9. Microfibrillated cellulose : Energy-efficient preparation techniques and key properties

    OpenAIRE

    Ankerfors, Mikael

    2012-01-01

    This work describes three alternative processes for producing microfibrillated cellulose (MFC) in which pulp fibres are first pre-treated and then homogenized using a high-pressure homogenizer. In one process, fibre cell wall delamination was facilitated with a combined enzymatic and mechanical pre-treatment. In the two other processes, cell wall delamination was facilitated by pre-treatments that introduced anionically charged groups into the fibre wall, by means of either a carboxymethylati...

  10. Potassium-titanyl-phosphate (KTP Laser and Dental Bleaching. Literature review.

    Directory of Open Access Journals (Sweden)

    Consuelo Arce

    2013-12-01

    Full Text Available ABSTRACT Objective: To determinate if dental bleaching with KTP laser is a safe, effective and efficient technique. The use of KTP laser for dental bleaching was only investigated in combination with a high concentration of hydrogen peroxide (35%. The recommended protocol was: for the use of KTP laser at 3W power and an irradiation time of ten seconds, three to four cycles are needed. For a power of 1W and an irradiation time of thirty seconds the number of cycles is three with a maximum of four. Under these conditions KTP laser bleaching was considered not to alter surface morphology, to have no influence on enamel microhardness, to maintain the pulp temperature within normal values, to obtain lighter tooth color which can be maintained for months (no long term studies were conducted. Because the bleaching effect was obtained in a short period of time and maintained for months, KTP laser bleaching was considered an effective and efficient technique. Conclusion: KTP-assisted dental bleaching is a safe, effective and efficient technique when combined with high concentration of hydrogen peroxide. RESUMEN Láser Potasio-Titanil-Fosfato (KTP y Blanqueamiento Dental. Revisión narrativa.Resumen: Objetivo: Determinar si el blanqueamiento dental con láser KTP es una técnica segura, efectiva y eficiente. El uso de láser KTP para blanqueamiento dental fue solo investigado en combinación con una alta concentración de peróxido de hidrogeno (35%. El protocolo recomendado fue: para el uso de láser KTP a 3W de potencia y un tiempo de irradiación de diez segundos, tres a cuatro repeticiones son necesarias. Para una potencia de 1W y un tiempo de irradiación de treinta segundos, el número de repeticiones son tres con un máximo de cuatro veces. Bajo estas condiciones, el blanqueamiento dental con esta técnica no altera la morfología de la superficie dental, no tiene influencia en la microdureza del esmalte, mantiene la temperatura pulpar dentro de

  11. ALKALINE PEROXIDE MECHANICAL PULPING OF FAST GROWTH PAULOWNIA WOOD

    Directory of Open Access Journals (Sweden)

    Ahmad Jahan Latibari,

    2011-11-01

    Full Text Available Alkaline peroxide mechanical pulping of paulownia wood harvested from exotic tree plantations in northern Iran was investigated. The fiber length, width, and cell wall thickness of this wood were measured as 0.82 mm, 40.3 μm, and 7.1 μm, respectively. The chemical composition including cellulose, lignin, and extractives soluble in ethanol-acetone, 1% NaOH, hot and cold water was determined as 49.5%, 25%, 12.1%, 26.9%, 11.4%, and 8.1% respectively. The ash content of this wood was 0.45%. Pre-washed chips were chemically treated at 70°C for 120 minutes with different combinations of three dosages (1.5, 3, and 4.5% of hydrogen peroxide and three dosages (1.5, 3, and 4.5% of sodium hydroxide prior to defibration. Other chemicals including DTPA, sodium silicate, and MgSO4 were constant at 0.5%, 3%, and 0.5%, respectively. The results showed that using a 1.5% hydrogen peroxide and 4.5% sodium hydroxide charge, the brightness of APMP pulp reached 68.7% ISO and higher chemical dosages did not improve the brightness; however, to produce APMP pulp with higher strength, a sodium hydroxide charge of 4.5% was needed. The tensile strength, tear strength, burst strength indices, and bulk density of the APMP pulp produced from 1.5% hydrogen peroxide and 4.5% sodium hydroxide were measured as 15.5Nm/g, 6.54mN.m2/g, 0.56kPa.m2/g, and 3.47cm3/g, respectively. The resulting pulp was bulky and is suitable for use in the middle layer of boxboard to provide the desired stiffness with a lower basis weight.

  12. STUDIES ON HIBISCUS CANNABINUS, HIBISCUS SABDARIFFA, AND CANNABINUS SATIVA PULP TO BE A SUBSTITUTE FOR SOFTWOOD PULP- PART 2: SAS-AQ AND NSSC-AQ DELIGNIFICATION PROCESSES

    Directory of Open Access Journals (Sweden)

    Dharm Dutt

    2010-08-01

    Full Text Available Hibiscus cannabinus, Cannabis sativa, and Hibiscus sabdariffa, fast growing productive annual plants, could provide fiber necessary to partially alleviate the world’s fiber deficit. The present study aimed at producing high yield pulp and the best mechanical strength properties with minimum impact on environment by SAS-AQ, and NSSC-AQ pulping processes. A total alkali of 13% (as Na2O, an alkali ratio of 0.80, and a Na2SO3 charge 11.70% (as Na2O were found optimum to reduce maximum kappa number. A lower kappa number and good strength properties were achieved by increasing total alkali and Na2SO3 charge. SAS-AQ pulps showed good response towards CEHH bleaching. The NSSC-AQ pulping was conducted at a total alkali charge of 8% (as Na2O by varying the ratio of sulphite-to-carbonate (100:0-0:100, and cooking time (60-120 min at 1600C. A ratio of sulphite-to-carbonate 60:40 was suitable for corrugating medium (cooking time 60 min, while a ratio of sulphite-to-carbonate 70:30 showed better strength properties (longer cooking time.

  13. Preparation nanowhiskers pulp from residue of palm fiber Attalea funifera Martius

    International Nuclear Information System (INIS)

    The residue from piassava fiber is higher in cellulose and lignin. This study aimed to extract the pulp and the development of methodology for preparation nanowhiskers from residue fiber. The first step extraction of cellulose, the second step to obtain the nanoparticles by acid hydrolysis (H2SO4). The samples were characterized by: SEM, chemical composition, TGA, FTIR and XRD. The XRD result shows that cellulose is of type I and TGA shows two events at 54 deg C and 370 deg C attributed to mass loss of water and cellulose, respectively. After hydrolysis, X-ray diffraction showed an intense reflection 2θ= 22.3 deg and an increase in the degree of crystallinity to 70% which is an indication of the formation of nanowhiskers. (author)

  14. Biological treatments affect the chemical composition of coffee pulp.

    Science.gov (United States)

    Ulloa Rojas, J B; Verreth, J A J; Amato, S; Huisman, E A

    2003-09-01

    Biological treatments were applied to fresh coffee pulp (CoP) to improve its nutritive value for monogastric animals by reducing its content of cellulose and antinutritional factors (ANFs) such as total phenols, tannins and caffeine. Treatments were: (1) ensiling with 0, 50 and 100 gkg(-1) molasses for 2 and 3 months, (2) aerobic decomposition for 0, 7, 14, 21, 28, 35 and 42 days, (3) aerobic bacterial inoculation (Bacillus sp.) for 0, 7, 14, 21 and 28 days. Ensiled CoP (E-CoP) showed higher fat and ash contents than oven-dried-CoP (OD-CoP; P<0.05). Similarly, true protein values tended to increase. The cellulose and total phenols levels of E-CoP were lower than OD-CoP (P<0.05). The E-CoP tannins levels tended to be lower than OD-CoP whereas caffeine levels remained unaffected. Improvement in the nutritional quality of E-CoP was associated with higher fat and protein contents and reduction of cellulose, total phenols and tannins. The aerobic decomposition treatment improved the nutritional quality of CoP by increasing true protein and fat contents. In addition, total phenols, tannins, caffeine and cellulose contents were reduced by an increase in treatment time (P<0.05). Bacterial treatment increased the protein content of CoP after 21 days (from 137 to 392 gkg(-1)) and decreased it after 28 days. Cellulose, total phenols, tannins and caffeine contents reduced with an increase in time of bacterial degradation. Bacterial treatment improved the CoP quality by increasing protein content and reducing cellulose and ANFs, especially after 21 days of treatment. Both the aerobic decomposition (after 21-28 days) and the aerobic bacterial degradation of CoP (after 21 days) appeared more suitable to improve the nutritional quality of CoP than the ensiling.

  15. Laser and LED external teeth-bleaching

    Science.gov (United States)

    Zanin, Fatima A.; Brugnera, Aldo, Jr.; Marchesan, Melissa A.; Pecora, Jesus D.

    2004-09-01

    Teeth-bleaching is an initial phase in the reproduction of an aesthetic smile; thus, it is very important that the dentist knows how to diagnose the causes of color changes and indicate whitening before proposing dental treatment. Technological advances in teeth-whitening lead to the development of new techniques, improving comfort, security and decreasing time of execution: argon laser, diode Laser, LED whitening, xenon light whitening. The clearing agent used in all techniques, including home whitening, is hydrogen peroxide (H2O2) in different concentrations. In this study, the authors describe mechanisms of gel activation, the use of Laser and LED"s for teeth-bleaching, the importance of diagnosis and the comfort of the patient in in-office teeth-bleaching techniques.

  16. 抗菌纤维素/纤维素纤维的研究进展%Research progress of antibacterial cellulose/cellulose fiber

    Institute of Scientific and Technical Information of China (English)

    徐永建; 左磊刚

    2014-01-01

    介绍了常用的无机抗菌剂和有机抗菌剂的种类及其抗菌机理,阐述了载银抗菌纤维素、纳米TiO2抗菌纤维素、季铵盐类抗菌纤维素、壳聚糖改性抗菌纤维素等抗菌纤维素及其在纺织工业、膜材料等方面的应用。指出了根据所选抗菌剂的不同,通过化学或物理方法可对纤维素和纤维素纤维进行抗菌改性。绒毛浆是一次性卫生用品吸水性垫层用绒毛化的纤维素纤维,对绒毛浆进行抗菌性改性能够提高绒毛浆的品质和功能。提出了可用于绒毛浆纤维抗菌性改性的抗菌剂和可能的方法,抗菌纤维素纤维改性在绒毛浆生产和应用中存在潜在应用前景。同时,提出了抗菌纤维素/纤维素纤维在生产和应用中存在的问题和解决办法。%The commonly used inorganic antibacterial agent and organic antibacterial agent , and their types and antibacterial mechanism were introduced .Silver antibacterial cellulose , nano TiO2 antibacterial cellulose , quaternary ammonium antibacterial cellulose , chitosan modified bacterial cellulose and other antimicrobial cellulose and its application in the textile industry ,film material and other applications were elaborated .According to the selected type of antibacterial agent ,cellulose and cellulose fibers can be modified by chemical or physical method ,fluff pulp is fluffed cellulose fibers used in disposable sanitary absorbent mat ,and fluff pulp can improve its quality and function by antibacterial modified .Paper introduced the possible antimicrobial agent and methods can be used in the antibacterial modified of fluff pulp fibers ,and the potential prospect of antibacterial modified of cellulose fibers in the pro-duction and application fluff pulp .Meanwhile the problems and solutions were presented in the production and application of antibacterial cellulose and cellulose fiber .

  17. The Effects of Habitat on Coral Bleaching Responses in Kenya

    OpenAIRE

    Grimsditch, Gabriel; Mwaura, Jelvas M.; Kilonzo, Joseph; Amiyo, Nassir

    2010-01-01

    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 (200...

  18. Side effects of external tooth bleaching

    DEFF Research Database (Denmark)

    E.M., Bruzell; Pallesen, Ulla; Thoresen, N.R.;

    2013-01-01

    -office = 39.3% [n = 28]; p >0.05; 95% CI [OR]: 0.198‑1.102) whereas prevalence of gingival irritation was higher after in-office treatment (at-home = 14.0%; in-office = 35.7%; p ... 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...

  19. Detrimental effects of host anemone bleaching on anemonefish populations

    Science.gov (United States)

    Saenz-Agudelo, P.; Jones, G. P.; Thorrold, S. R.; Planes, S.

    2011-06-01

    Coral bleaching and related reef degradation have caused significant declines in the abundance of reef-associated fishes. Most attention on the effects of bleaching has focused on corals, but bleaching is also prevalent in other cnidarians, including sea anemones. The consequences of anemone bleaching are unknown, and the demographic effects of bleaching on associated fish recruitment, survival, and reproduction are poorly understood. We examined the effect of habitat degradation including host anemone bleaching on fish abundance, egg production, and recruitment of the panda anemonefish ( Amphiprion polymnus) near Port Moresby, Papua New Guinea. Following a high-temperature anomaly in shallow waters of the region, most shallow anemones to a depth of 6 m (approximately 35% of all the anemones in this area) were severely bleached. Anemone mortality was low but bleached anemones underwent a ~34% reduction in body size. Total numbers of A. polymnus were not affected by bleaching and reduction in shelter area. While egg production of females living in bleached anemones was reduced by ~38% in 2009 compared to 2008, egg production of females on unbleached anemones did not differ significantly between years. Total recruitment in 2009 was much lower than in 2008. However, we found no evidence of recruiting larvae avoiding bleached anemones at settlement suggesting that other factors or different chemical cues were more important in determining recruitment than habitat quality. These results provide the first field evidence of detrimental effects of climate-induced bleaching and habitat degradation on reproduction and recruitment of anemonefish.

  20. 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...... pumping devices. ©2007 American Institute of Physics....

  1. Cellulose synthase interacting protein: A new factor in cellulose synthesis

    OpenAIRE

    Gu, Ying; Somerville, Chris

    2010-01-01

    Cellulose is the most abundant biopolymer on earth. The great abundance of cellulose places it at the forefront as a primary source of biomass for renewable biofuels. However, the knowledge of how plant cells make cellulose remains very rudimentary. Cellulose microfibrils are synthesized at the plasma membrane by hexameric protein complexes, also known as cellulose synthase complexes. The only known components of cellulose synthase complexes are cellulose synthase (CESA) proteins until the re...

  2. Electrically conductive cellulose composite

    Science.gov (United States)

    Evans, Barbara R.; O'Neill, Hugh M.; Woodward, Jonathan

    2010-05-04

    An electrically conductive cellulose composite includes a cellulose matrix and an electrically conductive carbonaceous material incorporated into the cellulose matrix. The electrical conductivity of the cellulose composite is at least 10 .mu.S/cm at 25.degree. C. The composite can be made by incorporating the electrically conductive carbonaceous material into a culture medium with a cellulose-producing organism, such as Gluconoacetobacter hansenii. The composites can be used to form electrodes, such as for use in membrane electrode assemblies for fuel cells.

  3. Fenomena Bleaching Karang Tahun 2009 di Pulau Badi Selat Makassar (Coral Bleaching Event on 2009 in Badi Island Makassar Strait)

    OpenAIRE

    Yusuf, Syafyudin; Rani, Chair; Jompa, Jamaluddin

    2010-01-01

    Bleaching event is loss of zooxanthella from the marine organisms tissue, as a caused by enviromental stress. Coral bleaching fenomenom was observed on May and June 2009 in Badi Island on Makassar Strait, Indonesia . The method used in this study is identified the photos coral colonies which bleaching infected were photographed with a Ixus Digital Canon 75 camera in an underwater housing. The results showed that the bleaching corals are caused by temperature anomaly above 1,24oC higher...

  4. Effects of ozone on kraft process pulp mill effluent

    Energy Technology Data Exchange (ETDEWEB)

    Mohammed, A. (Stanley Industrial Consultants, Edmonton, Alberta (Canada)); Smith, D.W. (Univ. of Alberta, Edmonton, (Canada))

    1992-12-01

    Effluent from a kraft process pulp mill was studied in a batch reactor for ozone doses between 50 and 200 mg O[sub 3]/L to identify the suitability of ozone application locations in the treatment process and see the improvements in biotreatability of wastewaters from a kraft process pulp mill. Laboratory acclimatized seed were used for (Biochemical Oxygen Demand) BOD tests for ozonated and unozonated samples. The inhibitory effects were minimized by using optimum dilutions. The studies were divided into three major sections: characterization of mill effluent; ozone system calibration, and reactor design; and ozonation of mill effluent. Seed for BOD tests were acclimatized in batch units for primary, bleach and secondary effluents separately. The results were analyzed using the [open quote]t[close quote] test for paired experiments and an ANOVA table for statistical confirmation. Residuals were plotted to check the assumptions of constant variance and normal distribution. It was concluded that ozone is most effective for the removal of color and the increase of BOD in secondary effluent. 21 refs., 9 figs., 7 tabs.

  5. REMINERALIZATION POTENTIAL OF A CARBAMIDE BLEACHING AGENT

    Directory of Open Access Journals (Sweden)

    Borislavova Marinova-Takorova Mirela

    2016-03-01

    Full Text Available Background: Bleaching has gradually became a popular procedure for people searching for aesthetic improvement. The aim of this in vitro study was to investigate the effect of bleaching with 45% carbamide peroxide on the level of mineralization of enamel, using laser fluorescence. Materials and methods: Sixty extracted human teeth were treated with 45% carbamid peroxide (Opalescence, Ultradent, 4 consecutive days for one hour each day. The effect of the bleaching agent on the level of mineralization of enamel was measured with DIAGNO dent pen. The statistical method we use was descriptive analysis. Results: The average values, measured before the applications of the carbamid peroxide were 6.33. On the first day they were 5.41, on the second 5.38, on the third 5.11 and 5.35 on the forth. Conclusion: There was observed a slight remineralization effect due to the incorporated Ca2+ and F- ions in the bleaching agent that we have used.

  6. Bark derived submicron-sized and nano-sized cellulose fibers: From industrial waste to high performance materials.

    Science.gov (United States)

    Nair, Sandeep S; Yan, Ning

    2015-12-10

    In this study, the use of bark as a natural source for the production of cellulose nanofibers has been explored for the first time. The fibrillation using bleached and unbleached cellulose fibers from the bark yielded sub-micron scale (20%) have never been possible from any other sources. The maximum elastic modulus value of 15.6 GPa and tensile strength value of 76 MPa were obtained for the films made from fibrillated bark cellulose fibers. The water vapour barrier efficiency for these films is comparable to nanocellulose films from other studies. PMID:26428123

  7. EFFECT OF PAPERMAKING CONDITIONS ON THE RETENTION OF REVERSIBLE THERMOCHROMIC MICROCAPSULE IN PULP

    OpenAIRE

    Xiaozhou Li; Yunhui Luo; Zhu Long; Cuihua Dong,

    2011-01-01

    Reversible thermochromic paper able to resist counterfeiting was prepared by adding reversible thermochromic microcapsules (RTM) to a slurry of cellulosic fibers, a process that is difficult to imitate. However, the loss of RTM is one of the biggest problems that inhibits industrial use of this approach. So, the retention of RTM in pulp was investigated. The RTM was synthesized by in-situ polymerization, and its properties were characterized. It exhibited strong color contrast between cool an...

  8. The electro-oxidation of lignin in Sappi Saiccor dissolving pulp effluent.

    OpenAIRE

    Moodley, B; Brookes, HC; Mulholland, DA

    2011-01-01

    Electro-oxidation reactions using a nickel anode were carried out on the calcium-spent liquor effluent obtained from Sappi Saiccor (formerly South African Industrial Cellulose Corporation) dissolving pulp mill as well as on lignin- and lignan-type compounds previously identified in the effluent. Voltammograms were obtained for each solution in order to identify the oxidation potentials of the compounds to be electro-oxidised. Value-added products such as vanillin and syringaldehyde were ident...

  9. Effects of cellulose whiskers on properties of soy protein thermoplastics.

    Science.gov (United States)

    Wang, Yixiang; Cao, Xiaodong; Zhang, Lina

    2006-07-14

    Environmentally-friendly SPI/cellulose whisker composites were successfully prepared using a colloidal suspension of cellulose whiskers, to reinforce soy protein isolate (SPI) plastics. The cellulose whiskers, having an average length of 1.2 microm and diameter of 90 nm, respectively, were prepared from cotton linter pulp by hydrolyzing with sulfuric acid aqueous solution. The effects of the whisker content on the morphology and properties of the glycerol-plasticized SPI composites were investigated by scanning electron microscopy, dynamic mechanical thermal analysis, differential scanning calorimetry, ultraviolet-visible spectroscopy, water-resistivity testing and tensile testing. The results indicated that, with the addition of 0 to 30 wt.-% of cellulose whiskers, strong interactions occurred both between the whiskers and between the filler and the SPI matrix, reinforcing the composites and preserving their biodegradability. Both the tensile strength and Young's modulus of the SPI/cellulose whisker composites increased from 5.8 to 8.1 MPa and from 44.7 to 133.2 MPa, respectively, at a relative humidity of 43%, following an increase of the whisker content from 0 to 30 wt.-%. Furthermore, the incorporation of the cellulose whiskers into the SPI matrix led to an improvement in the water resistance for the SPI-based composites.

  10. Enamel alteration following tooth bleaching and remineralization.

    Science.gov (United States)

    Coceska, Emilija; Gjorgievska, Elizabeta; Coleman, Nichola J; Gabric, Dragana; Slipper, Ian J; Stevanovic, Marija; Nicholson, John W

    2016-06-01

    The purpose of this study was to compare the effects of professional tooth whitening agents containing highly concentrated hydrogen peroxide (with and without laser activation), on the enamel surface; and the potential of four different toothpastes to remineralize any alterations. The study was performed on 50 human molars, divided in two groups: treated with Opalescence(®) Boost and Mirawhite(®) Laser Bleaching. Furthermore, each group was divided into five subgroups, a control one and 4 subgroups remineralized with: Mirasensitive(®) hap+, Mirawhite(®) Gelleѐ, GC Tooth Mousse™ and Mirafluor(®) C. The samples were analysed by SEM/3D-SEM-micrographs, SEM/EDX-qualitative analysis and SEM/EDX-semiquantitative analysis. The microphotographs show that both types of bleaching cause alterations: emphasized perikymata, erosions, loss of interprizmatic substance; the laser treatment is more aggressive and loss of integrity of the enamel is determined by shearing off the enamel rods. In all samples undergoing remineralization deposits were observed, those of toothpastes based on calcium phosphate technologies seem to merge with each other and cover almost the entire surface of the enamel. Loss of integrity and minerals were detected only in the line-scans of the sample remineralized with GC Tooth Mousse™. The semiquantitative EDX analysis of individual elements in the surface layer of the enamel indicates that during tooth-bleaching with HP statistically significant loss of Na and Mg occurs, whereas the bleaching in combination with a laser leads to statistically significant loss of Ca and P. The results undoubtedly confirm that teeth whitening procedures lead to enamel alterations. In this context, it must be noted that laser bleaching is more aggressive for dental substances. However, these changes are reversible and can be repaired by application of remineralization toothpastes. PMID:27197087

  11. Response of white sucker (Catostomus commersoni) to pulp and paper mill effluent in the Androscoggin River, Maine, USA.

    Science.gov (United States)

    Mower, Barry F; Munkittrick, Kelly R; McMaster, Mark E; Van Beneden, Rebecca J

    2011-01-01

    Adverse effects of pulp and paper mill effluent on fish populations have been well documented in many countries over the last two decades. Some of the initial studies were at mills with conventional chlorine bleaching and no secondary effluent treatment. Following installation of secondary treatment, changes in bleaching technology to elemental chlorine-free bleaching, and other process changes, adverse effects on fish were reduced or eliminated at some mills. Because no two mills are exactly alike, it is difficult to predict adverse impacts of any given mill on fish populations. In 1994, a study of female white sucker (Catostomus commersoni) in the Androscoggin River, Maine, USA, showed induction of mixed function oxidase, reductions in gonad size and plasma estradiol, and an increase in plasma testosterone in fish downstream of discharges from three large bleached kraft pulp and paper mills, and host community municipal sewage treatment plants (STP). After all three mills switched to elemental chlorine-free bleaching in the late 1990s, studies from 2001 to 2003 found that the pattern of reproductive impacts on white sucker populations measured in 1994 was not repeated. In addition, population estimates of white sucker from 2002 to 2003 using mark-recapture techniques found that densities and biomass were well within the range of those of a reference population, and of those reported in the literature for unimpacted populations. Detailed studies immediately above and below each mill/sewage treatment plant showed no evidence of reproductive effects. However, a clear pattern of eutrophication was noted, which increased cumulatively downstream below each mill/STP. PMID:20872897

  12. Synthesis of cellulose acetate and carboxymethylcellulose from sugarcane straw.

    Science.gov (United States)

    Candido, R G; Gonçalves, A R

    2016-11-01

    Sugarcane straw (SCS) is a raw material with high potential for production of cellulose derivatives due to its morphology and structure. The proposal of this work was to synthesize cellulose acetate (CA) and carboxymethylcellulose (CMC) from sugarcane straw cellulose, and applied the CA in the preparation of a membrane. The cellulose extraction was carried out in four steps. Firstly, SCS was treated with H2SO4 (10% v/v) followed by NaOH (5% w/v) treatment. Subsequently, a chelating process was performed before ending the extraction process with chemical bleaching using H2O2 (5% v/v). The extracted cellulose was employed in the obtainment of CA and CMC. The CA presented a degree of substitution (DS) of 2.72. Its FTIR spectrum showed that practically all hydroxyl groups were replaced by acetate groups. The membrane synthesized from CA was dense and homogeneous. The presence of small particles on the top and bottom surfaces decreased the mechanical resistance of the membrane. The CMC presented a low DS (0.4) demonstrating the carboxymethylation reaction was not very effective due to the presence of lignin. These results proved that SCS can be utilized in the synthesis of CA and CMC. PMID:27516319

  13. Extraction and Characterization of Nano cellulose from Coconut Fiber

    International Nuclear Information System (INIS)

    Coconut husk fibers has been modified by some chemical treatments to extract cellulose nano crystals (CNC), which are alkali treatment, bleaching and acid hydrolysis using concentrated sulphuric acid. The effect of the treatments on the coconut husk fibers has been analysed using Fourier transform infrared (FTIR) and X-Ray diffraction (XRD). Meanwhile, the morphology observation and thermal stability of the fiber have been analysed by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) respectively. The analyses show that the chemical modification could eliminate some of the lignin and hemicelluloses of the fiber. Nano cellulose extracted from acid hydrolysis has been analysed using transmission electron microscopy (TEM) to define the size of extracted nano cellulose. The cellulose nano crystals from coconut fibre has the average diameter and length in the range 13.7±6.2 nm and 172.3±8.4 nm, respectively. The obtained nano cellulose may have the potential applications in the fields of biomedical, oil adsorption, membrane, pharmaceutical and bio composites. (author)

  14. Reactions of chlorine (III) and their kinetics in the chlorine dioxide bleaching of kraft pulps

    OpenAIRE

    Lehtimaa, Tuula

    2010-01-01

    The reactions of Cl(III) were investigated utilizing iodometric titration in combination with DMSO and EDTA to prevent undesired side reactions. Among a large group of suggested Cl(III) decomposition reactions, two reactions were found to be adequate to describe the Cl(III) decomposition in the absence of metals and HOCl. The rate parameters (k - rate coefficient, Ea - activation energy) were determined for these reactions. The reaction between Cl(III) and HOCl is known to start with the...

  15. A novel paleo-bleaching proxy using boron isotopes and high-resolution laser ablation to reconstruct coral bleaching events

    Directory of Open Access Journals (Sweden)

    G. Dishon

    2015-06-01

    Full Text Available Coral reefs occupy only ~0.1% of the oceans habitat, but are the most biologically diverse marine ecosystem. In recent decades, coral reefs have experienced significant global declines due to a variety of causes, one of the major being widespread coral bleaching events. During bleaching the coral expels its symbiotic algae losing its main source of nutrition generally obtained through photosynthesis. While recent coral bleaching events have been extensively investigated, there is no scientific data on historical coral bleaching prior to 1979. In this study, we employ high-resolution femtosecond Laser Ablation Multiple Collector Inductively Coupled Plasma Mass Spectrometry (LA-MC-ICP-MS to demonstrate a distinct biologically-induced decline of boron (B isotopic composition (δ11B as a result of coral bleaching. These findings and methodology offer a new use for a previously developed isotopic proxy to reconstruct paleo-coral bleaching events. Based on a literature review of published δ11B data and our recorded "vital effect" of coral bleaching on the δ11B signal, we also describe at least two possible coral bleaching events since the Last Glacial Maximum. The implementation of this bleaching proxy holds the potential of identifying occurrences of coral bleaching throughout the geological record. A deeper temporal view of coral bleaching will enable scientists to determine if it occurred in the past during times of environmental change and what outcome it may have had on coral population structure.

  16. 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

  17. Changes in bleaching susceptibility among corals subject to ocean warming and recurrent bleaching in Moorea, French Polynesia.

    Directory of Open Access Journals (Sweden)

    Morgan S Pratchett

    Full Text Available 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

  18. The decontamination of bleaching effluent by pilot-scale solar Fenton process.

    Science.gov (United States)

    Wang, Zhaojiang; Chen, Kefu; Li, Jun; Mo, Lihuan

    2011-01-01

    A solar Fenton process was applied as post-treatment to selectively eliminate organic pollutants and toxicants in bleaching effluents of kraft pulp mills. Experiments were conducted to study the effect of system parameters (pH, initial concentration of H2O2, molar ratio of Fe2+/H2O2 and solar-UV irradiance) on the removals of chemical oxygen demand and colour. The results showed 92.8% of COD and 99.6% of colour were removed at pH 3.5, H2O2 30 mM/ L, Fe2+/H2O2 1:100, solar-UV irradiance 11070 mW/m2, reaction time 120 min. The first-order kinetic model was used to study the dependence of the reaction rate on solar-UV irradiance: a linear relationship was shown to exist between reaction rate constants and solar-UV irradiance. The results of gas chromatography mass spectrometry analysis showed that the toxicity of the bleaching effluents was mainly derived from the presence of mononuclear aromatics, polycyclic aromatic hydrocarbons and organochlorides, which were all degraded into harmless organic acids under the attack of hydroxyl radicals generated from the solar Fenton reaction. PMID:21879547

  19. SEPARATION AND CHARACTERIZATION OF NEW CELLULOSIC FIBRES FROM THE JUNCUS ACUTUS L PLANT

    Directory of Open Access Journals (Sweden)

    Amel El Ghali,

    2012-02-01

    Full Text Available Cellulose fibres from the Juncus acutus L plant were isolated and characterized. The isolation of the fibres was performed by sequential NaOH treatment and H2O2 bleaching under different extraction conditions. The chemical and surface morphological structures of the Juncus acutus L fibres were characterized with FTIR, SEM, AFM, DSC, surface energy, diameter, density, and lignin content determination. Changes in structure and properties of the obtained fibres were observed by varying the concentration and the treatment time of the applied process. Results revealed that the optimum conditions to remove most of non-cellulosic materials from the Juncus acutus L plant were 7M NaOH, 3h and 100°C for alkaline procedure, and 10 mL.L-1 H2O2, 45 minutes and 95°C for bleaching treatment.

  20. Cellulose whiskers from sisal fibers: a study about the variable of extraction by acid hydrolysis

    International Nuclear Information System (INIS)

    The incorporation of cellulosic nanostructures in polymeric matrices has been studied due to their properties of biodegradation, and expected higher mechanical performance than the traditional composites. In this work, cellulose nanofibers were obtained from sisal bleached with reagents without chlorine, where it was used an acid mixture, with acetic acid and nitric acid, and after the bleached fibers were submitted to acid hydrolysis. The influence of the temperature and time of hydrolysis on the morphology and dimensions, crystallinity and thermal stability were analyzed by scanning transmission electronic microscopy (TEM), x-ray diffraction (XRD) and thermogravimetric analysis (TGA), respectively. The hydrolysis condition of 60 deg C and 15 minutes showed to be the most effective condition to obtain whiskers from sisal fibers, resulting in nanostructures with higher crystallinity and thermal. (author)

  1. Cellulose nanocrystal from pomelo (C. Grandis osbeck) albedo: Chemical, morphology and crystallinity evaluation

    International Nuclear Information System (INIS)

    Citrus peel is one of the under-utilized waste materials that have potential in producing a valuable fibre, which are cellulose and cellulose nanocrystal. Cellulose was first isolated from pomelo (C. Grandis Osbeck) albedo by combination of alkali treatment and bleaching process, followed by acid hydrolysis (65% H2SO4, 45 °C, 45min) to produce cellulose nanocrystal. The crystalline, structural, morphological and chemical properties of both materials were studied. Result reveals the crystallinity index obtained from X-ray diffraction for cellulose nanocrystal was found higher than extracted cellulose with the value of 60.27% and 57.47%, respectively. Fourier transform infrared showed that the chemical treatments removed most of the hemicellulose and lignin from the pomelo albedo fibre. This has been confirmed further by SEM and TEM for their morphological studies. These results showed that cellulose and cellulose nanocrystal were successfully obtained from pomelo albedo and might be potentially used in producing functional fibres for food application

  2. Cellulose nanocrystal from pomelo (C. Grandis osbeck) albedo: Chemical, morphology and crystallinity evaluation

    Science.gov (United States)

    Zain, Nor Fazelin Mat; Yusop, Salma Mohamad; Ahmad, Ishak

    2013-11-01

    Citrus peel is one of the under-utilized waste materials that have potential in producing a valuable fibre, which are cellulose and cellulose nanocrystal. Cellulose was first isolated from pomelo (C. Grandis Osbeck) albedo by combination of alkali treatment and bleaching process, followed by acid hydrolysis (65% H2SO4, 45 °C, 45min) to produce cellulose nanocrystal. The crystalline, structural, morphological and chemical properties of both materials were studied. Result reveals the crystallinity index obtained from X-ray diffraction for cellulose nanocrystal was found higher than extracted cellulose with the value of 60.27% and 57.47%, respectively. Fourier transform infrared showed that the chemical treatments removed most of the hemicellulose and lignin from the pomelo albedo fibre. This has been confirmed further by SEM and TEM for their morphological studies. These results showed that cellulose and cellulose nanocrystal were successfully obtained from pomelo albedo and might be potentially used in producing functional fibres for food application.

  3. Cellulose nanocrystal from pomelo (C. Grandis osbeck) albedo: Chemical, morphology and crystallinity evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Zain, Nor Fazelin Mat; Yusop, Salma Mohamad [Food Science Program, School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Selangor (Malaysia); Ahmad, Ishak [Polymer Research Centre (PORCE), School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Selangor (Malaysia)

    2013-11-27

    Citrus peel is one of the under-utilized waste materials that have potential in producing a valuable fibre, which are cellulose and cellulose nanocrystal. Cellulose was first isolated from pomelo (C. Grandis Osbeck) albedo by combination of alkali treatment and bleaching process, followed by acid hydrolysis (65% H{sub 2}SO{sub 4}, 45 °C, 45min) to produce cellulose nanocrystal. The crystalline, structural, morphological and chemical properties of both materials were studied. Result reveals the crystallinity index obtained from X-ray diffraction for cellulose nanocrystal was found higher than extracted cellulose with the value of 60.27% and 57.47%, respectively. Fourier transform infrared showed that the chemical treatments removed most of the hemicellulose and lignin from the pomelo albedo fibre. This has been confirmed further by SEM and TEM for their morphological studies. These results showed that cellulose and cellulose nanocrystal were successfully obtained from pomelo albedo and might be potentially used in producing functional fibres for food application.

  4. ISOLATION AND CHARACTERIZATION OF CELLULOSE AND LIGNIN FROM STEAM-EXPLODED LIGNOCELLULOSIC BIOMASS

    Directory of Open Access Journals (Sweden)

    Maha M. Ibrahim

    2010-02-01

    Full Text Available The isolation of cellulose from different lignocellulosic biomass sources such as corn cob, banana plant, cotton stalk, and cotton gin waste, was studied using a steam explosion technology as a pre-treatment process for different times followed by alkaline peroxide bleaching. The agricultural residues were steam-exploded at 220 ºC for 1-4 min for the corn cob, 2 and 4 min for the banana plant, 3-5 min for the cotton gin waste, and for 5 min for the cotton stalk. The steamed fibers were water extracted followed by alkali extraction and finally peroxide bleaching to yield cellulose with different degrees of crystallinity. The degree of polymerization of the cellulose fraction ranged from 167.4 to 1615.7. Longer residence time of the steam explosion led to an increase in cellulose crystallinity. The ten isolated cellulose samples were further characterized by SEM, FT-IR, and thermal analysis. Four lignin preparations were also obtained from steam-exploded corn cob, banana plant, cotton stalk, and cotton gin waste after alkali treatment. The SEM micrographs of the lignin showed different morphological structure for the different agricultural residues. The FT-IR and TGA analyses showed that the steam pre-treatment led to an extensive cleavage of ether bonds, condensation reactions, and some demethylation of aromatic methoxyl groups in the lignin structure. The thermal stabilities of the isolated lignins were different for different agricultural residues.

  5. New Technology of Refiner Bleaching with Magnesium Hydroxide and Hydrogen Peroxide%磨浆过程中添加氢氧化镁和过氧化氢进行漂白的新技术

    Institute of Scientific and Technical Information of China (English)

    姚光裕

    2012-01-01

    Conventional bleaching of mechanical pulp with magnesium hydroxide and hydrogen peroxide shows significant economic benefits over bleaching with caustic soda, sodium silicate and hydrogen per oxide, using magnesium hydroxide and hydrogen peroxide bleaching mechanical pulp generates lower effluent COD/BOD,higher pulp yield, solvesed oxalate scaling and so on. North pacific has developed this bleaching new technology into production thermo mechanical pulp. The excellent mixing,high temperature and high consistency of the refining environment solubi lize the magnesium hydroxide and provide an excellent bleach reactor with addition of hydrogen perox ide. Addition magnesium hydroxide and hydrogen peroxide into the refining system,refiner energy de mand is reduced by 100~200kW ·h/t · pulp and pulp strength is improved by 5~10%.%由氢氧化钠+过氧化氢+硅酸钠转变成氢氧化镁+过氧化氢漂白机械浆具有明显的经济效益。采用氢氧化镁+过氧化氢漂白预热木片磨木浆产生废水COD/BOD负荷较低、纸浆得率较高和解决了草酸盐结垢等等。North pacific造纸公司研制出这种漂白新技术已用于生产预热木片磨木浆工厂。由于在磨浆过程中添加氢氧化镁+过氧化氢,在高温和高浓度下使浆料和漂白化学品很好混和,提供过氧化氢极佳的漂白反应,添加氢氧化镁+过氧化氢到磨浆系统,使磨浆所需能量降低100~200kW·h/t浆,并可提高纸浆强度5%~10%。

  6. Reef fishes can recognize bleached habitat during settlement: sea anemone bleaching alters anemonefish host selection.

    Science.gov (United States)

    Scott, Anna; Dixson, Danielle L

    2016-05-25

    Understanding how bleaching impacts the settlement of symbiotic habitat specialists and whether there is flexibility in settlement choices with regard to habitat quality is essential given our changing climate. We used five anemonefishes (Amphiprion clarkii, Amphiprion latezonatus, Amphiprion ocellaris, Amphiprion percula and Premnas biaculeatus) and three host sea anemones (Entacmaea quadricolor, Heteractis crispa and Heteractis magnifica) in paired-choice flume experiments to determine whether habitat naive juveniles have the olfactory capabilities to distinguish between unbleached and bleached hosts, and how this may affect settlement decisions. All anemonefishes were able to distinguish between bleached and unbleached hosts, and responded only to chemical cues from species-specific host anemones irrespective of health status, indicating a lack of flexibility in host use. While bleached hosts were selected as habitat, this occurred only when unbleached options were unavailable, with the exception of A. latezonatus, which showed strong preferences for H. crispa regardless of health. This study highlights the potential deleterious indirect impacts of declining habitat quality during larval settlement in habitat specialists, which could be important in the field, given that bleaching events are becoming increasingly common. PMID:27226472

  7. SOME ASPECTS OF THE REACTIVITY OF PULP INTENDED FOR HIGH-VISCOSITY VISCOSE

    Directory of Open Access Journals (Sweden)

    Linda Ostberg,

    2012-01-01

    Full Text Available The motivation for this study was to reduce the consumption of C2S when preparing high-viscosity viscose by pre-treating two softwood pulps with enzymes prior to the viscose stages. Reactivity was evaluated in two ways, Fock´s test of the pulp and the gamma number of the viscose solution prior to regeneration. Whilst the reactivity of a pulp that had been subjected to enzyme pretreatment increased according to Fock´s test, it did not increase according to the gamma number. This unexpected difference between the two reactivity tests was investigated. It was concluded that Fock´s test measures the extent to which C2S reacts with a pulp sample during a standardized test, whereas the gamma number measures the resulting degree of xanthate substitution on the cellulose backbone. The gamma number was judged to be the more relevant of the two tests, since it reflects the dissolution ability of a pulp in the viscose preparation. A higher gamma number also means that the coagulation time in the spinning process is prolonged; this is beneficial, as it can be used to increase the tenacity of the viscose fibres. Measuring the reactivity according to Fock´s test, on the contrary, provides more dubious results, as the test has no undisputed correlation to the viscose preparation process.

  8. Extraction and Characterization of Nanocellulose Structures from Linter Dissolving Pulp Using Ultrafine Grinder.

    Science.gov (United States)

    Ghasemi, Somayeh; Behrooz, Rabi; Ghasemi, Ismail

    2016-06-01

    The objective of this study was to extract cellulose nanofibrils (CNFs) from Linter dissolving pulp through a simple and environmentally friendly physical method of refining pretreatment coupled with ultrafine grinder. The morphology, structure and properties of the Linter pulp and obtained NFCs were investigated using Optical Microscopy (OM), electron microscopy (SEM), Atomic Force Microscopy (AFM), Fourier transformed infrared (FTIR) spectra, X-ray diffraction (XRD) and Thermogravimetric (TG) analysis. The OM results indicate that, the Linter Pulp had length and wide mainly ranged 1.3 mm and 13 μm respectively. Based on AFM images, most of extracted nanocellulose had spherical shape and the average of nanocellulose diameter was varied between 30-70 nm when measured by AFM and SEM. Also the FTIR spectra confirmed that the basic structure of nanocellulose was maintained and no derivative was formed. The X-ray results show that by this method of extraction, the crystallinity index of Nanocellulose isolated (62%) decreased in compared to Linter Pulp (79.5%). Also Linter pulp decomposes at higher temperature (280 degrees C) than isolated nanocellulose (240 degrees C). PMID:27427633

  9. ETHANOL PULPING AS A STAGE IN THE BIO-REFINERY OF OLIVE TREE PRUNINGS

    Directory of Open Access Journals (Sweden)

    Ana Requejo,

    2012-06-01

    Full Text Available Biomaterials from olive tree pruning are an abundant agricultural residue in various Mediterranean regions. A suggested use of this residue is its separation in a main fraction (trunks and stems with diameter > 1 cm and a residual fraction (leaves and stems with diameter 1 < cm, using biorefinery procedures. The main fraction is cooked with ethanol, giving rise to a pulp, which can be used either in paper or in bioethanol production if before pulping the main fraction is subjected to a hydrothermal treatment. Pulping with 70% ethanol concentration, 185 °C for 80 min resulted in a pulp with a yield of 46.30% and a content of holocellulose, α-cellulose, and lignin of 77.17%, 62.49%, and 21.73%, respectively. The paper sheets obtained had a breaking length of 1168 m, a burst index of 0.44 kN /g, a tear index of 2.25 mN.m2/g, and a brightness of 43.66%. The pulp converted into bioethanol (by simultaneous hydrolysis and fermentation achieved a conversion of 70 g bioethanol/100 g potential bioethanol. The residual fraction of olive tree prunings was subjected to combustion to produce thermal energy. The heating value was 18700 kJ/kg, the flame temperature range was 1094 to 2013 ºC, and the dew point temperature range of the flue gases was 47 to 53 °C.

  10. Cellulose binding domain proteins

    Energy Technology Data Exchange (ETDEWEB)

    Shoseyov, Oded (Karmey Yosef, IL); Shpiegl, Itai (Rehovot, IL); Goldstein, Marc (Davis, CA); Doi, Roy (Davis, CA)

    1998-01-01

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production thereof. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques.

  11. New Parameter for In-Office Dental Bleaching

    OpenAIRE

    Presoto, Cristina Dupim; Janaina Freitas BORTOLATTO; Carvalho, Priscila Petrucelli Freire de; Trevisan, Tamara Carolina; Floros, Michael Christopher; Junior, Osmir Batista de Oliveira

    2016-01-01

    Dental bleaching is considered a conservative and biologically safe treatment for discolored teeth. Despite this, one of the major undesirable effects of bleaching is dentin sensitivity which may occur during and after treatment. To address these sensitivity issues, new dental bleaching preparations with lower concentrations of hydrogen peroxide (H2O2) have recently been introduced to the market. This paper presents a clinical case report of a 20-year-old female patient admitted to the Araraq...

  12. Evaluation of peanut hulls as an alternative to bleaching clays

    OpenAIRE

    Hassanein, M. M.M.; El- Shami, S. M.; Taha, F. S.

    2011-01-01

    Peanut hulls (PNH) were carbonized at different temperatures, times, and evaluated at different concentrations as an alternative to bleaching clays. Evaluation of bleached crude soybean oil with PNH was based on their delta free fatty acids, reduction in peroxide value (PV), reduction in phospholipids (PL) and bleachability. The performance of several commercially used bleaching clays was evaluated, for comparison. Mixtures were formulated including: PNH and Tonsil -N (TN), PNH and Fuller’s e...

  13. Effectiveness of bleaching agent on composite resin discoloration

    OpenAIRE

    Galih Sampoerno

    2012-01-01

    Background: The discoloration of teeth, especially anterior teeth, is one of aesthetic problems. The use of tooth bleaching agents for discolored natural teeth is becoming increasingly popular. Many dentists, however, get many problems when they conduct bleaching process since there is much composite filling on patient’s anterior teeth. Although many research have focused on the discoloration of composite resin after bleaching process, the problem still becomes debatable. Purpose: The purpose...

  14. Coral community response to bleaching on a highly disturbed reef

    OpenAIRE

    Guest, J R; Low, J.; Tun, K.; Wilson, B.; Ng, C.; D. Raingeard; Ulstrup, K. E.; Tanzil, J. T. I.; Todd, P.A.; Toh, T. C.; McDougald, D; Chou, L. M.; Steinberg, P D

    2016-01-01

    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:...

  15. A global protocol for monitoring of coral bleaching

    OpenAIRE

    Oliver, J.; Setiasih, N.; Marshall, P.; Hansen, L.

    2004-01-01

    Coral bleaching and subsequent mortality represent a major threat to the future health and productivity of coral reefs. However a lack of reliable data on occurrence, severity and other characteristics of bleaching events hampers research on the causes and consequences of this important phenomenon. This article describes a global protocol for monitoring coral bleaching events, which addresses this problem and can be used by people with different levels of expertise and resources.

  16. Terahertz Properties of Cellulose Nanocrystals and Films

    Science.gov (United States)

    Carnio, B. N.; Ahvazi, B.; Elezzabi, A. Y.

    2016-03-01

    Terahertz (THz) radiation properties of cellulose nanocrystal (CNC) films, a CNC powder, and a dissolving pulp film are examined using THz time-domain spectroscopy. The relative permittivity (real component) of the CNC samples are found to vary between 1.78 and 3.81, over the frequency range of 0.2-1.5 THz, despite the fact that they are made from the same linear chain of glucose monomers. The results show that the permittivity is strongly dependent on the source from which the CNC glucose monomers are extracted, as well as on the drying process used. The THz loss tangent (0.043 < tan( δ) < 0.145), absorption coefficient (3.5 cm-1 < α < 63.7 cm-1), and growth-varying permittivity, combined with other appealing thermal and mechanical characteristic of CNC, make such material attractive for use in both passive and potential THz bandwidth electronic components.

  17. 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

    2016-01-01

    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. PMID:26876092

  18. Mass coral bleaching in 2010 in the southern Caribbean.

    Directory of Open Access Journals (Sweden)

    Jahson Berhane Alemu I

    Full Text Available 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.

  19. Effects of dental trauma on the pulp.

    Science.gov (United States)

    Love, R M

    1997-05-01

    Infection of the root canal system following dental trauma induces pulp and periapical disease and prevents healing of previously healthy pulp. A clinical goal in treating trauma is the maintenance of pulp vitality, and clinicians should be aware of factors that influence pulp healing. The learning objective of this article is to review the factors and techniques that influence pulp vitality and examine the influence pulp has on the healing of adjacent tissues. The potential routes for bacterial infection of the root canal system are discussed, with the clinical crown as the primary portal of entry. Uncomplicated and complicated crown fractures, as well as the crown-root and root fractures, are reviewed. Complications in pulp healing include canal obliteration, disturbed root development, apexogenesis, apexification, and the various forms of resorption.

  20. 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.

  1. Fermentative characteristics of coffee pulp silage with different proportions of coffee hulls

    Directory of Open Access Journals (Sweden)

    Adauto Ferreira Barcelos

    2013-03-01

    Full Text Available This study aimed to evaluate the chemical composition and fermentation characteristics of the coffee pulp silages with different proportions of coffee hulls. The material was ensiled in PVC with 150 mm diameter by 750 mm high, according to the treatments: coffee pulp (CoP, CoP + 20% of coffee hulls (CH, CoP + 40% of CH and CoP + 60% CH in a completely randomized design with six replications. The silos were opened 60 days after closing, when samples were taken for determination of dry matter (DM, crude protein (CP, neutral detergent fiber (NDF, acid detergent fiber (ADF, lignin, cellulose, pH, N-NH3, caffeine, calcium (Ca, phosphorus (P and in vitro digestibility of dry matter. We also determined gas production and effluent. There was a linear increase in DM content and pH, and a linear decrease of CP, NDF and ADF, lignin, cellulose, caffeine, Ca and P. This reduction occurs because the coffee hulls have lower levels than pulp to CP, NDF, ADF, caffeine, Ca and P. There was also a linear reduction in N-NH3 values, and only the highest percentage of silage with coffee hulls obtained below 10%, considered as the limit for good quality silage. Effluent production was higher for silage shelled coffee pulp and do not get any production in silage with 60% coffee hull. There was no significant difference in vitro digestibility of dry matter among treatments. The coffee hulls was effective in increasing DM content of CoP silage and to reduce NDF, ADF, N-NH3, providing nutritional value of silage satisfactory for cattle feed, creating an alternative for recovery of such waste. When considering the DM content found in silages, the amount of bark best coffee to be added to coffee pulp for the production of silage is between 30% and 35%.

  2. A novel paleo-bleaching proxy using boron isotopes and high-resolution laser ablation to reconstruct coral bleaching events

    Science.gov (United States)

    Dishon, G.; Fisch, J.; Horn, I.; Kaczmarek, K.; Bijma, J.; Gruber, D. F.; Nir, O.; Popovich, Y.; Tchernov, D.

    2015-10-01

    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 extensively investigated, there is no scientific data on historical coral bleaching prior to 1979. In this study, we employ high-resolution femtosecond Laser Ablation Multiple Collector Inductively Coupled Plasma Mass Spectrometry (LA-MC-ICP-MS) to demonstrate a distinct biologically induced decline of boron (B) isotopic composition (δ11B) as a result of coral bleaching. These findings and methodology offer a new use for a previously developed isotopic proxy to reconstruct paleo-coral bleaching events. Based on a literature review of published δ11B data and our recorded vital effect of coral bleaching on the δ11B signal, we also describe at least two possible coral bleaching events since the Last Glacial Maximum. The implementation of this bleaching proxy holds the potential of identifying occurrences of coral bleaching throughout the geological record. A deeper temporal view of coral bleaching will enable scientists to determine if it occurred in the past during times of environmental change and what outcome it may have had on coral population structure. Understanding the frequency of bleaching events is also critical for determining the relationship between natural and anthropogenic causes of these events.

  3. A novel paleo-bleaching proxy using boron isotopes and high-resolution laser ablation to reconstruct coral bleaching events

    OpenAIRE

    Dishon, G.; Fisch, J.; Horn, I.; K. Kaczmarek; Bijma, J.; D. F. Gruber; O. Nir; Y. Popovich; D. Tchernov

    2015-01-01

    Coral reefs occupy only ~0.1% of the oceans habitat, but are the most biologically diverse marine ecosystem. In recent decades, coral reefs have experienced significant global declines due to a variety of causes, one of the major being widespread coral bleaching events. During bleaching the coral expels its symbiotic algae losing its main source of nutrition generally obtained through photosynthesis. While recent coral bleaching events hav...

  4. A novel paleo-bleaching proxy using boron isotopes and high-resolution laser ablation to reconstruct coral bleaching events

    OpenAIRE

    Dishon, G.; Fisch, J.; Horn, I.; K. Kaczmarek; Bijma, J.; D. F. Gruber; O. Nir; Y. Popovich; D. Tchernov

    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...

  5. Pulp Regeneration: Current Approaches and Future Challenges.

    Science.gov (United States)

    Yang, Jingwen; Yuan, Guohua; Chen, Zhi

    2016-01-01

    Regenerative endodontics aims to replace inflamed/necrotic pulp tissues with regenerated pulp-like tissues to revitalize teeth and improve life quality. Pulp revascularization case reports, which showed successful clinical and radiographic outcomes, indicated the possible clinical application of pulp regeneration via cell homing strategy. From a clinical point of view, functional pulp-like tissues should be regenerated with the characterization of vascularization, re-innervation, and dentin deposition with a regulated rate similar to that of normal pulp. Efficient root canal disinfection and proper size of the apical foramen are the two requisite preconditions for pulp regeneration. Progress has been made on pulp regeneration via cell homing strategies. This review focused on the requisite preconditions and cell homing strategies for pulp regeneration. In addition to the traditionally used mechanical preparation and irrigation, antibiotics, irrigation assisted with EndoVac apical negative-pressure system, and ultrasonic and laser irradiation are now being used in root canal disinfection. In addition, pulp-like tissues could be formed with the apical foramen less than 1 mm, although more studies are needed to determine the appropriate size. Moreover, signaling molecules including stromal cell derived factor (SDF-1α), basic Fibroblast Growth Factor (bFGF), Platelet Derived Growth Factor (PDGF), stem cell factor (SCF), and Granulocyte Colony-Stimulating Factor (G-CSF) were used to achieve pulp-like tissue formation via a cell homing strategy. Studies on the cell sources of pulp regeneration might give some indications on the signaling molecular selection. The active recruitment of endogenous cells into root canals to regenerate pulp-like tissues is a novel concept that may offer an unprecedented opportunity for the near-term clinical translation of current biology-based therapies for dental pulp regeneration. PMID:27014076

  6. Pulp regeneration: Current approaches and future challenges

    Directory of Open Access Journals (Sweden)

    Jingwen eYANG

    2016-03-01

    Full Text Available Regenerative endodontics aims to replace inflamed/necrotic pulp tissues with regenerated pulp-like tissues to revitalize teeth and improve life quality. Pulp revascularization case reports, which showed successful clinical and radiographic outcomes, indicated the possible clinical application of pulp regeneration via cell homing strategy. From a clinical point of view, functional pulp-like tissues should be regenerated with the characterization of vascularization, re-innervation, and dentin deposition with a regulated rate similar to that of normal pulp. Efficient root canal disinfection and proper size of the apical foramen are the two requisite preconditions for pulp regeneration. Progress has been made on pulp regeneration via cell homing strategies. This review focused on the requisite preconditions and cell homing strategies for pulp regeneration. In addition to the traditionally used mechanical preparation and irrigation, antibiotics, irrigation assisted with EndoVac apical negative-pressure system, and ultrasonic and laser irradiation are now being used in root canal disinfection. In addition, pulp-like tissues could be formed with the apical foramen less than 1 mm, although more studies are needed to determine the appropriate size. Moreover, signaling molecules including stromal cell derived factor (SDF-1α, basic Fibroblast Growth Factor (bFGF, Platelet Derived Growth Factor (PDGF, stem cell factor (SCF, and Granulocyte Colony-Stimulating Factor (G-CSF were used to achieve pulp-like tissue formation via a cell homing strategy. Studies on the cell sources of pulp regeneration might give some indications on the signaling molecular selection. The active recruitment of endogenous cells into root canals to regenerate pulp-like tissues is a novel concept that may offer an unprecedented opportunity for the near-term clinical translation of current biology-based therapies for dental pulp regeneration.

  7. Oxidative stress and bioindicators of reproductive function in pulp and paper mill effluent exposed white sucker.

    Science.gov (United States)

    Oakes, Ken D; McMaster, Mark E; Pryce, Andrea C; Munkittrick, Kelly R; Portt, Cam B; Hewitt, L Mark; MacLean, Dan D; Van Der Kraak, Glen J

    2003-07-01

    This study investigates oxidative stress and bioindicators of reproductive function in wild white sucker (Catostomus commersoni) collected from environments receiving pulp and paper mill effluent discharges in northern Ontario. Samples were collected over an eight-year period adjacent to three pulp and paper mills using a variety of processing and bleaching techniques. Fish collected downstream of pulp and paper mills within the Moose River basin exhibited elevated hepatic and gonadal 2-thiobarbituric acid reactive substances (TBARS), the presence of which is indicative of oxidative stress in these tissues. Within the Jackfish Bay system, exposure to pulp and paper mill effluent did not elevate hepatic or gonadal TBARS. Hepatic cytochrome P4501A activity (CYP1A) and fatty acyl-CoA oxidase (FAO) activities were frequently increased in livers of Moose River basin fish exposed to pulp and paper mill effluent, while lower activities of both enzymes were found within fish from the Jackfish Bay system. This suggests that oxidative stress may be related to CYP1A and FAO activities. Within the Moose River system, increases in measures of oxidative stress (TBARS, FAO) were generally coincident with decreased levels of 17 beta-estradiol; however, testosterone was often lower in Jackfish Bay system fish without any commensurate changes in oxidative stress. The suite of reproductive and oxidative stress parameters measured in this study varied between seasons and mills suggesting responses to effluent are dynamic and effects are complicated by different receiving environments. The relationship between gonad size, gonadal oxidative stress, and circulating plasma steroids remains unclear. PMID:12730610

  8. Simultaneous production of α-cellulose and furfural from bagasse by steam explosion pretreatment

    OpenAIRE

    Vittaya Punsuvon

    2008-01-01

    Sugar cane bagasse was pretreated by steam explosion for the simultaneous production of furfural and α-cellulose pulp. The components of bagasse were fractionated after steam explosion. The details of the process are as follows. Bagasse was soaked in water for one night and steamed at temperatures varying between 206 and 223 C for 4 minutes. The steam exploded pulp was strained and washed with hot water to yield a liquor rich in hemicellulose-derived mono- and oligosaccharides. The remaining...

  9. Direct ethanol production from cassava pulp using a surface-engineered yeast strain co-displaying two amylases, two cellulases, and {beta}-glucosidase

    Energy Technology Data Exchange (ETDEWEB)

    Apiwatanapiwat, Waraporn; Rugthaworn, Prapassorn [Japan International Research Center for Agricultural Sciences (JIRCAS), Tsukuba, Ibaraki (Japan). Post-Harvest Science and Technology Div.; Kasetsart Univ., Bangkok (Thailand). Nanotechnology and Biotechnology Div.; Murata, Yoshinori; Kosugi, Akihiko; Arai, Takamitsu; Mori, Yutaka [Japan International Research Center for Agricultural Sciences (JIRCAS), Tsukuba, Ibaraki (Japan). Post-Harvest Science and Technology Div.; Yamada, Ryosuke; Kondo, Akihiko [Kobe Univ. (Japan). Dept. of Chemical Science and Engineering

    2011-04-15

    In order to develop a method for producing fuel ethanol from cassava pulp using cell surface engineering (arming) technology, an arming yeast co-displaying {alpha}-amylase ({alpha}-AM), glucoamylase, endoglucanase, cellobiohydrase, and {beta}-glucosidase on the surface of the yeast cells was constructed. The novel yeast strain, possessing the activities of all enzymes, was able to produce ethanol directly from soluble starch, barley {beta}-glucan, and acid-treated Avicel. Cassava is a major crop in Southeast Asia and used mainly for starch production. In the starch manufacturing process, large amounts of solid wastes, called cassava pulp, are produced. The major components of cassava pulp are starch (approximately 60%) and cellulose fiber (approximately 30%). We attempted simultaneous saccharification and ethanol fermentation of cassava pulp with this arming yeast. During fermentation, ethanol concentration increased as the starch and cellulose fiber substrates contained in the cassava pulp decreased. The results clearly showed that the arming yeast was able to produce ethanol directly from cassava pulp without addition of any hydrolytic enzymes. (orig.)

  10. Uses of peroxide on the formation of chlorinated phenolics by gas chromatography technique in nonwood pulps to reduce toxicity in paper manufacturing

    Science.gov (United States)

    Prakash, Divya; Kumar, S.; Tomar, Neeraj

    2016-05-01

    ECF technology has been established itself as the most preferred process worldwide. Peroxide addition minimizes the effluent color. The study deals with the bleaching of Bamboo and Jute Cady pulps with chlorine and peroxide treatment and identification of various chlorophenolics compounds. The results show that quantity of the total chlorophenolic compounds formed decreases up to 54% in total chlorophenolic compound in the CEH effluent and the COD and color values are reduced by 35% and 33% respectively as E stage is changed to Ep stage in Bamboo pulp. And there is a reduction of 52% in total chlorophenolic compound in the CEH effluent when E stage is changed to Ep. and the COD and color values are reduced by 30% and 33% respectively as E stage is changed to Ep stage in Jute Cady pulp

  11. 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

  12. Evaluation of Extraradicular Diffusion of Hydrogen Peroxide during Intracoronal Bleaching Using Different Bleaching Agents

    Directory of Open Access Journals (Sweden)

    Mohammad E. Rokaya

    2015-01-01

    Full Text Available Objectives. Extra radicular diffusion of hydrogen peroxide associated with intracoronal teeth bleaching was evaluated. Methods. 108 intact single rooted extracted mandibular first premolars teeth were selected. The teeth were instrumented with WaveOne system and obturated with gutta percha and divided into four groups (n=27 according to the bleaching materials used. Each main group was divided into three subgroups (n=9 according to the time of extra radicular hydrogen peroxide diffusion measurements at 1, 7, and 14 days: group 1 (35% hydrogen peroxide, group 2 (35% carbamide peroxide, group 3 (sodium perborate-30% hydrogen peroxide mixture, and group 4 (sodium perborate-water mixture. Four cemental dentinal defects were prepared just below the CEJ on each root surface. The amount of hydrogen peroxide that leached out was evaluated after 1, 7, and 14 days by spectrophotometer analysis. The results were analyzed using the ANOVA and Tukey’s test. Results. Group 1 showed highest extra radicular diffusion, followed by group 3 and group 2, while group 4 showed the lowest mean extra radicular diffusion. Conclusion. Carbamide peroxide and sodium perborate-water mixture are the most suitable bleaching materials used for internal bleaching due to their low extra radicular diffusion of hydrogen peroxide.

  13. TECHNICAL NOTE: Electrically aligned cellulose film for electro-active paper and its piezoelectricity

    Science.gov (United States)

    Yun, Sungryul; Jang, Sangdong; Yun, Gyu-Young; Kim, Jaehwan

    2009-11-01

    Electrically aligned regenerated cellulose films were fabricated and the effect of applied electric field was investigated for the piezoelectricity of electro-active paper (EAPap). The EAPap was fabricated by coating gold electrodes on both sides of regenerated cellulose film. The cellulose film was prepared by dissolving cotton pulp in LiCl/N,N-dimethylacetamide solution followed by a cellulose chain regeneration process. During the regeneration process an external electric field was applied in the direction of mechanical stretching. Alignment of cellulose fiber chains was investigated as a function of applied electric field. The material characteristics of the cellulose films were analyzed by using an x-ray diffractometer, a field emission scanning electron microscope and a high voltage electron microscope. The application of external electric fields was found to induce formation of nanofibers in the cellulose, resulting in an increase in the crystallinity index (CI) values. It was also found that samples with higher CI values showed higher in-plane piezoelectric constant, d31, values. The piezoelectricity of the current EAPap films was measured to be equivalent or better than that of ordinary PVDF films. Therefore, an external electric field applied to a cellulose film along with a mechanical stretching during the regeneration process can enhance the piezoelectricity.

  14. SALIENT FEATURES OF BAMBOO FIBRE

    Institute of Scientific and Technical Information of China (English)

    Subrata Das

    2007-01-01

    @@ Bamboo fibre is a regenerated cellulosic fibre produced from bamboo. Starchy pulp is produced from bamboo stems and leaves through a process of alkaline hydrolysis and multiphase bleaching. Further chemical processes produce bamboo fibre.

  15. SALIENT FEATURES OF BAMBOO FIBRE

    Institute of Scientific and Technical Information of China (English)

    Subrata; Das

    2007-01-01

    Bamboo fibre is a regenerated cellulosic fibre produced from bamboo.Starchy pulp is produced from bamboo stems and leaves through a process of alkaline hydrolysis and multi- phase bleaching.Further chemical processes produce bamboo fibre.

  16. Cellulose Synthesis and Its Regulation

    OpenAIRE

    Li, Shundai; Bashline, Logan; Lei, Lei; Gu, Ying

    2014-01-01

    Cellulose, the most abundant biopolymer synthesized on land, is made of linear chains of ß (1–4) linked D-glucose. As a major structural component of the cell wall, cellulose is important not only for industrial use but also for plant growth and development. Cellulose microfibrils are tethered by other cell wall polysaccharides such as hemicellulose, pectin, and lignin. In higher plants, cellulose is synthesized by plasma membrane-localized rosette cellulose synthase complexes. Despite the re...

  17. Integrated hydrolyzation and fermentation of sugar beet pulp to bioethanol.

    Science.gov (United States)

    Rezić, Tonči; Oros, Damir; Marković, Iva; Kracher, Daniel; Ludwig, Roland; Santek, Božidar

    2013-09-28

    Sugar beet pulp is an abundant industrial waste material that holds a great potential for bioethanol production owing to its high content of cellulose, hemicelluloses, and pectin. Its structural and chemical robustness limits the yield of fermentable sugars obtained by hydrolyzation and represents the main bottleneck for bioethanol production. Physical (ultrasound and thermal) pretreatment methods were tested and combined with enzymatic hydrolysis by cellulase and pectinase to evaluate the most efficient strategy. The optimized hydrolysis process was combined with a fermentation step using a Saccharomyces cerevisiae strain for ethanol production in a single-tank bioreactor. Optimal sugar beet pulp conversion was achieved at a concentration of 60 g/l (39% of dry weight) and a bioreactor stirrer speed of 960 rpm. The maximum ethanol yield was 0.1 g ethanol/g of dry weight (0.25 g ethanol/g total sugar content), the efficiency of ethanol production was 49%, and the productivity of the bioprocess was 0.29 g/l·h, respectively. PMID:23851274

  18. Investigating Motivations for Women's Skin Bleaching in Tanzania

    Science.gov (United States)

    Lewis, Kelly M.; Robkin, Navit; Gaska, Karie; Njoki, Lillian Carol

    2011-01-01

    Why do many African women continue to use damaging skin-bleaching cosmetics that contain dangerous chemicals (e.g., mercury) that may increase their rates of infertility, skin cancer, and serious skin/brain/kidney disease? To address this question, our study investigated motivations driving the preservation of skin-bleaching practices in Tanzania.…

  19. 21 CFR 872.6475 - Heat source for bleaching teeth.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Heat source for bleaching teeth. 872.6475 Section 872.6475 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6475 Heat source for bleaching...

  20. Fulton Cellulosic Ethanol Biorefinery

    Energy Technology Data Exchange (ETDEWEB)

    Sumait, Necy [BlueFire Ethanol, Irvine, CA (United States); Cuzens, John [BlueFire Ethanol, Irvine, CA (United States); Klann, Richard [BlueFire Ethanol, Irvine, CA (United States)

    2015-07-24

    Final report on work performed by BlueFire on the deployment of acid hydrolysis technology to convert cellulosic waste materials into renewable fuels, power and chemicals in a production facility to be located in Fulton, Mississippi.

  1. Integrated biorefinery concept for grass silage using a combination of adapted pulping methods for advanced saccharification and extraction of lignin.

    Science.gov (United States)

    Schwarz, Dominik; Dörrstein, Jörg; Kugler, Sabine; Schieder, Doris; Zollfrank, Cordt; Sieber, Volker

    2016-09-01

    An integrated refining and pulping process for ensiled biomass from permanent grassland was established on laboratory scale. The liquid phase, containing the majority of water-soluble components, including 24% of the initial dry matter (DM), was first separated by mechanical pressing. The fiber fraction was subjected to high solid load saccharification (25% DM) to enhance the lignin content in the feed for subsequent organosolvation. The saccharification enzymes were pre-selected applying experimental design approaches. Cellulose convertibility was improved by a secondary pressing step during liquefaction. Combined saccharification and organosolvation showed high degree of saccharide solubilization with recovery of 98% of the glucan and 73% of the xylan from the fiber fraction in the hydrolysates, and enabled the recovery of 41% of the grass silage lignin. The effects of the treatment were confirmed by XRD and SEM tracking of cellulose crystallinity and fiber morphology throughout the pulping procedure. PMID:27262721

  2. Integrated biorefinery concept for grass silage using a combination of adapted pulping methods for advanced saccharification and extraction of lignin.

    Science.gov (United States)

    Schwarz, Dominik; Dörrstein, Jörg; Kugler, Sabine; Schieder, Doris; Zollfrank, Cordt; Sieber, Volker

    2016-09-01

    An integrated refining and pulping process for ensiled biomass from permanent grassland was established on laboratory scale. The liquid phase, containing the majority of water-soluble components, including 24% of the initial dry matter (DM), was first separated by mechanical pressing. The fiber fraction was subjected to high solid load saccharification (25% DM) to enhance the lignin content in the feed for subsequent organosolvation. The saccharification enzymes were pre-selected applying experimental design approaches. Cellulose convertibility was improved by a secondary pressing step during liquefaction. Combined saccharification and organosolvation showed high degree of saccharide solubilization with recovery of 98% of the glucan and 73% of the xylan from the fiber fraction in the hydrolysates, and enabled the recovery of 41% of the grass silage lignin. The effects of the treatment were confirmed by XRD and SEM tracking of cellulose crystallinity and fiber morphology throughout the pulping procedure.

  3. Preparation of Cellulosic Membrane Containing Pyrrolidone Moiety Via Radiation Induced Grafting and its Application in Wastewater Treatment

    Directory of Open Access Journals (Sweden)

    A. S. Aly

    2005-01-01

    Full Text Available Radiation induced grafting of vinyl pyrrolidone onto cellulose wood pulp was carried out in heterogeneous and homogenous media using gamma radiation. Cellulose wood pulp was used in different forms; a in a homogenous solution by dissolving the wood pulp in N,N- dimethylacetamide/Lithium chloride (DMAc/LiCl mixture , b in a membrane form, by precipitating the cellulose solution in water and c in a powder form. Factors affecting on the grafting such as radiation dose, monomer concentration, precipitator concentration and thickness of the membrane have been studied. The result showed that at the same dose, the grafting yield was higher with cellulose in soluble form than in the membrane form, whereas cellulose in powder exhibited the lowest graft yield. The grafted membrane was characterized by IR, TGA and SEM. The ability of the grafted membrane to remove dyes (acid and basic dye, heavy metal ions (Co 2+ , Ni 2+ and Cu 2+ and phenols from wastewater was also reported.

  4. [Functional morphology of pulp tissue].

    Science.gov (United States)

    Heine, H; Schaeg, G; Türk, R

    1989-01-01

    As compared with mesenchyme no genuine defense cells are developed in the tissue of the dental pulp and the nervous tissue. This is a further hint for the common development from ectoderm. The three dimensional meshwork of pulpa fibroblasts ("mesectoderm") is structured by elongated cell processes connected with each other by a variety of special cell junctions ("electronic cell coupling"). Metabolites from the microcirculation and neuropeptides from vegetative axons influence the activity of fibroblasts synthetizing groundsubstance. The meshwork of the groundsubstance has exclusion effects concerning molecules with a distinct molecular weight and charge. Thus a primitive defense system is established. With this the role of a newly described cell type of the dental pulp, the "lymphocytic pericyte" is discussed. Because of the poor capacity of the pulpa tissue for immunological reactions pathologically disorders may easily become chronically spreading their antigenic components throughout the body. PMID:2800671

  5. Characterization of the regenerated cellulose films in ionic liquids and rheological properties of the solutions

    Energy Technology Data Exchange (ETDEWEB)

    Liu Zhen; Wang Hui [Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Li Zengxi, E-mail: zxli@home.ipe.ac.cn [Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Lu Xingmei; Zhang Xiangping [State Key Laboratory of Multiphase Complex System, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Zhang Suojiang, E-mail: sjzhang@home.ipe.ac.cn [State Key Laboratory of Multiphase Complex System, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Zhou Kebin [Graduate University of Chinese Academy of Sciences, Beijing 100049 (China)

    2011-07-15

    Highlights: {yields} The solubility can reach 13 wt% at 90 deg. C in ionic liquid of [bmim]Cl. {yields} Additive N-methylimidazole can minimize DP loss of the regenerated films. {yields} A mechanism of the dissolution of cellulose in [bmim]Cl was proposed. {yields} The ionic liquid of [bmim]Cl could be recycled. - Abstract: Dissolution and regeneration of cotton pulp using ionic liquids as solvent was investigated. The physicochemical properties of the regenerated cellulose films have been characterized by scanning electron microscopy, X-ray diffractometer, infrared spectrometric analyzer, differential scanning calorimeter, and thermogravimetric analysis instrument. The rheological properties of cotton pulp dissolved in ionic liquids have been investigated by steady shear and oscillatory shear measurements. The influences of experimental parameters, such as the reaction temperature, additives on the solubility and degree of polymerization (DP) of regenerated cellulose were also studied. The results show that 1-butyl-3-methylimidazolium chloride ([bmim]Cl) was a good solvent to dissolve cotton pulp and the solubility can reach 13 wt% at 90 deg. C, but the DP remarkably decreased from 510 to 180 within 7 h. It was found that additive N-methylimidazole can effectively minimize DP loss of the regenerated cellulose, which can attribute to the fact that in the mixture of [bmim]Cl and NMI solution, the {beta}-1,4-glycosidic bond of the cellulose chains cannot be broken because of the relative low concentration of Cl{sup -}. In the steady shear measurement, all the solutions show a shear thinning behavior at high shear rates. In addition, a mechanism of the dissolution of cellulose in [bmim]Cl was proposed.

  6. The effect of bleaching on toothbrush abrasion of resin composites

    Directory of Open Access Journals (Sweden)

    Hila Hajizadeh

    2013-01-01

    Full Text Available Aim: This experimental study was designed to focus on the effects of bleaching on toothbrush abrasion in three types of composites with different filler size. Materials and Methods: Forty eight disks were prepared from three types of composite and divided into 6 groups. In the first three groups the abrasion test was done. The remaining groups were bleached and the abrasion test was performed. The weight of the samples before and after abrasion was measured. Statistical analysis was done with one-way ANOVA and Duncan test. Results: There was a significant difference in abrasion of composites with different filler size (P < 0.05. The most amount of abrasion was observed in Z100 after being bleached. An increase in abrasion was noticed in all three types of tested composite after bleaching. Conclusion: According to the findings, it is suggested to use a nano filled resin composite for restoration if the bleaching treatment is required.

  7. Effect of the Purple Corn Beverage “Chicha Morada” in Composite Resin during Dental Bleaching

    Science.gov (United States)

    Acuña, Eric Dario; Delgado-Cotrina, Leyla; Rumiche, Francisco Aurelio

    2016-01-01

    During dental bleaching the staining potential of the surface would increase. This study aims to evaluate the staining susceptibility of one bleached composite resin after the exposure to three different beverages: Peruvian purple corn based beverage (chicha morada), green tea, and distilled water. Thirty disk-shaped specimens of one nanofill composite resin were prepared. The specimens were then divided into six groups (n = 5): purple corn (P), purple corn + bleaching (PB), green tea (T), green tea + bleaching (TB), distilled water (W), and distilled water + bleaching (WB). In groups that received bleaching, two sessions of bleaching with 35% hydrogen peroxide were done. Following bleaching, specimens were exposed to each liquid thirty minutes daily. Color was measured with a digital spectrophotometer. For statistical analysis, color measurement differences between the obtained results were used: during bleaching, after bleaching, and during + after bleaching. Two-way ANOVA was used to compare the color changes in the resins of all groups (p 3.3). PMID:27034897

  8. Chemically-Modified Cellulose Paper as a Microstructured Catalytic Reactor

    Directory of Open Access Journals (Sweden)

    Hirotaka Koga

    2015-01-01

    Full Text Available We discuss the successful use of chemically-modified cellulose paper as a microstructured catalytic reactor for the production of useful chemicals. The chemical modification of cellulose paper was achieved using a silane-coupling technique. Amine-modified paper was directly used as a base catalyst for the Knoevenagel condensation reaction. Methacrylate-modified paper was used for the immobilization of lipase and then in nonaqueous transesterification processes. These catalytic paper materials offer high reaction efficiencies and have excellent practical properties. We suggest that the paper-specific interconnected microstructure with pulp fiber networks provides fast mixing of the reactants and efficient transport of the reactants to the catalytically-active sites. This concept is expected to be a promising route to green and sustainable chemistry.

  9. Caffeine reduction in coffee pulp through silage.

    Science.gov (United States)

    Porres, C; Alvarez, D; Calzada, J

    1993-01-01

    Silage tests to study reductions of antiphysiological compounds (caffeine and polyphenols) of fresh coffee pulp during the anaerobic fermentation were done. A concrete silo divided in compartments, with a total capacity of 9 tons of fresh material was utilized. The silage periods ranged between 99-224 days and the following materials were ensiled: 1) coffee pulp, 2) coffee pulp with sugar cane molasses, 3) coffee pulp with a mixture of molasses and ammonia and 4) screw pressed coffee pulp with molasses. Reductions in caffeine, total polyphenols and condensed polyphenols ranged between 13-63%, 28-70% and 51-81% respectively. It was concluded that in the case of coffee pulp, silage presents and ideal method to preserve the material and partially reduce the contents of antiphysiological compounds.

  10. Enzymatic hydrolysis of cellulose pretreated with ionic liquids and N-methyl Morpholine N-Oxide

    Science.gov (United States)

    Yau Li, Elizabeth

    The effect of N-methyl Morpholine N-Oxide (NMMO), 1-ethyl-3-methyl-imidazolium acetate ([Emim]Ac) and 1-ethyl-3-methyl-imidazolium diethyl phosphate ([Emim]DEP) on pretreatment and enzymatic hydrolysis of dissolving pulp was studied. X-ray diffraction measurements of regenerated cellulose from these solvents showed that solvent pretreatment reduces the crystallinity of cellulose. However, crystallinity might not be a major factor affecting the in-situ enzymatic hydrolysis of cellulose in these solvents. Although regenerated cellulose from [Emim]DEP showed the lowest crystallinity index (˜15%), in-situ enzymatic hydrolysis of cellulose dissolved in NMMO showed the highest cellulose conversion (68% compared to 65% for [Emim]Ac and 37% for [Emim]DEP at enzyme loading of 122 FPU/g). Moreover, results showed that enzymes could tolerate up to NMMO concentration of 100 g/L and still yield full conversion of cellulose. Since it is not necessary to remove all the NMMO, less amount of water will be required for the washing step and thus the process will be more economical. The HCH-1 model was used in an attempt to model the enzymatic hydrolysis of cellulose in NMMO. With the incorporation of NMMO inhibition and a factor to account for unreacted cellulose, the model was able to correlate the experimental data of the enzymatic hydrolysis of cellulose (6.68 g/L) at various NMMO concentrations (0, 50, 100, 150 and 250 g/L). However, the experimental results also suggest that NMMO might be deactivating the enzymes rather than inhibiting them. More studies need to be done at varying cellulose, NMMO and enzyme concentrations to find the exact nature of this deactivation of NMMO.

  11. Combination of enzymatic hydrolysis and ethanol organosolv pretreatments: effect on lignin structures, delignification yields and cellulose-to-glucose conversion.

    Science.gov (United States)

    Obama, Patrick; Ricochon, Guillaume; Muniglia, Lionel; Brosse, Nicolas

    2012-05-01

    Enzymatic pre-hydrolysis using the industrial enzymatic cocktail Cellulyve® was assessed as a first step in a pretreatment process of Miscanthus biomass involving an aqueous-ethanol organosolv treatment. (13)C and (31)P Nuclear Magnetic Resonance and size exclusion chromatography were used to analyze the cellulose and lignin before and after treatment. It was demonstrated that despite a very low impact on the fibre structure (observed by Scanning Electron Microscopy) and composition (in terms of sugars and polyphenolics content), the enzymatic pre-treatment disrupted the lignocellulosic matrix to a considerable extend. This weakening permitted enhanced removal of lignin during organosolv pulping and increased hydrolysability of the residual cellulosic pulp for the production of monomeric glucose. Using this combined treatment, a delignification yield of 93% and an enzymatic cellulose-to-glucose conversion of 75% were obtained. PMID:22424922

  12. 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. PMID:27561498

  13. RECYCLING OF VALUELESS PAPER DUST TO A LOW GRADE CELLULOSE ACETATE: EFFECT OF PRETREATMENTS ON ACETYLATION

    Directory of Open Access Journals (Sweden)

    Cheu Peng Leh,

    2012-01-01

    Full Text Available The feasibility of the production of cellulose acetate (CA from recycled paper dust from carton boxes was examined. Two pre-treatments were carried out on the carton box’s paper dust (CPD to improve the pulp properties for better effect of synthesis. The results showed that the acid and oxygen-alkaline pretreatments were capable of increasing the alpha-cellulose content from 80.5 percent to 87.3 percent and 85.3 percent, respectively. Both pre-treatments also decreased the hemicellulose and ash contents by more than 50 percent. The degree of substitution (DS of the resultant CA from pre-treated paper dust was improved from 1.94 to 2.13-2.16. The CA that was synthesized from the recycled paper dust showed comparable DS and had a similar trend of Fourier Transform Infrared (FTIR spectra. Both pretreated pulps also showed an increment in the degree of crystallinity and had maximum degradation effect of temperature when compared to CPD CA. However, all the cellulose acetates produced showed a lower DS and thermal stability compared to commercial cellulose acetate (C CA. The degree of crystallinity of all the cellulose acetate was decreased in comparison to the original material.

  14. PULP DEMAND IN THE INTERNATIONAL MARKET

    OpenAIRE

    Edmilson Santos Cruz; Antonio Donizette de Oliveira; José Roberto Soares Scolforo; José Luis Pereira de Rezende

    2003-01-01

    This study aimed at analyzing the international pulp market, taking into account themain exporting countries and importing regions, with the objective of estimating, for each market, theown-price and cross-price elasticity in relation to the demand of the pulp, differentiated for country oforigin. The model considers that imports are differentiated by origin; therefore they are not perfect substitutes. The demand from Europe, North America and the Rest of the World for the pulp from theUnited...

  15. Optimization of alkaline pretreatment of coffee pulp for production of bioethanol.

    Science.gov (United States)

    Menezes, Evandro G T; do Carmo, Juliana R; Alves, José Guilherme L F; Menezes, Aline G T; Guimarães, Isabela C; Queiroz, Fabiana; Pimenta, Carlos J

    2014-01-01

    The use of lignocellulosic raw materials in bioethanol production has been intensively investigated in recent years. However, for efficient conversion to ethanol, many pretreatment steps are required prior to hydrolysis and fermentation. Coffee stands out as the most important agricultural product in Brazil and wastes such as pulp and coffee husk are generated during the wet and dry processing to obtain green grains, respectively. This work focused on the optimization of alkaline pretreatment of coffee pulp with the aim of making its use in the alcoholic fermentation. A central composite rotatable design was used with three independent variables: sodium hydroxide and calcium hydroxide concentrations and alkaline pretreatment time, totaling 17 experiments. After alkaline pretreatment the concentration of cellulose, hemicellulose, and lignin remaining in the material, the subsequent hydrolysis of the cellulose component and its fermentation of substrate were evaluated. The results indicated that pretreatment using 4% (w/v) sodium hydroxide solution, with no calcium hydroxide, and 25 min treatment time gave the best results (69.18% cellulose remaining, 44.15% hemicelluloses remaining, 25.19% lignin remaining, 38.13 g/L of reducing sugars, and 27.02 g/L of glucose) and produced 13.66 g/L of ethanol with a yield of 0.4 g ethanol/g glucose.

  16. Optimization of alkaline pretreatment of coffee pulp for production of bioethanol.

    Science.gov (United States)

    Menezes, Evandro G T; do Carmo, Juliana R; Alves, José Guilherme L F; Menezes, Aline G T; Guimarães, Isabela C; Queiroz, Fabiana; Pimenta, Carlos J

    2014-01-01

    The use of lignocellulosic raw materials in bioethanol production has been intensively investigated in recent years. However, for efficient conversion to ethanol, many pretreatment steps are required prior to hydrolysis and fermentation. Coffee stands out as the most important agricultural product in Brazil and wastes such as pulp and coffee husk are generated during the wet and dry processing to obtain green grains, respectively. This work focused on the optimization of alkaline pretreatment of coffee pulp with the aim of making its use in the alcoholic fermentation. A central composite rotatable design was used with three independent variables: sodium hydroxide and calcium hydroxide concentrations and alkaline pretreatment time, totaling 17 experiments. After alkaline pretreatment the concentration of cellulose, hemicellulose, and lignin remaining in the material, the subsequent hydrolysis of the cellulose component and its fermentation of substrate were evaluated. The results indicated that pretreatment using 4% (w/v) sodium hydroxide solution, with no calcium hydroxide, and 25 min treatment time gave the best results (69.18% cellulose remaining, 44.15% hemicelluloses remaining, 25.19% lignin remaining, 38.13 g/L of reducing sugars, and 27.02 g/L of glucose) and produced 13.66 g/L of ethanol with a yield of 0.4 g ethanol/g glucose. PMID:24376222

  17. Cellulose whiskers from sisal fibers: a study about the variable of extraction by acid hydrolysis; Whiskers de cellulose obtido a partir de fibras de sisal: estudo de variaveis de extracao por hidrolise acida

    Energy Technology Data Exchange (ETDEWEB)

    Teodoro, Kelcilene B.R., E-mail: rakelcilene@ig.com.br [Universidade Federal de Sao Carlos - UFSCar, Sao Carlos, SP (Brazil); Teixeira, Eliangela de Morais; Correa, Ana Carolina; Campos, Adriana de; Marconcini, Jose Manoel; Mattoso, Luiz Henrique Capparelli [Empresa Brasileira de Pesquisa Agropecuaria - EMBRAPA, Sao Carlos, SP (Brazil). Lab. Nacional de Nanotecnologia para o Agronegocio (LNNA)

    2011-07-01

    The incorporation of cellulosic nanostructures in polymeric matrices has been studied due to their properties of biodegradation, and expected higher mechanical performance than the traditional composites. In this work, cellulose nanofibers were obtained from sisal bleached with reagents without chlorine, where it was used an acid mixture, with acetic acid and nitric acid, and after the bleached fibers were submitted to acid hydrolysis. The influence of the temperature and time of hydrolysis on the morphology and dimensions, crystallinity and thermal stability were analyzed by scanning transmission electronic microscopy (TEM), x-ray diffraction (XRD) and thermogravimetric analysis (TGA), respectively. The hydrolysis condition of 60 deg C and 15 minutes showed to be the most effective condition to obtain whiskers from sisal fibers, resulting in nanostructures with higher crystallinity and thermal. (author)

  18. Solid-state fermentation: an alternative to improve the nutritive value of coffee pulp.

    Science.gov (United States)

    Peñaloza, W; Molina, M R; Brenes, R G; Bressani, R

    1985-02-01

    Coffee pulp was subjected to a solid-state fermentation process, using Aspergillus niger. The initial moisture content of the pulp, as well as the fermentation time and temperature, had a significant effect on the increase in total amino acid content of the material. The increase in total amino acids showed a significant correlation with the dry matter recovered (r = -0.98) and the increase in pH during the process (r = 0.98). With a moisture content of 80%, a pH of 3.5, a temperature of 35 degrees C, and an aeration of 8 liters/min per kg as fermentation conditions, it was found that the maximum concentration of total amino acids was attained after 43 h. The fermented product had a higher total amino acid content and a lower cell wall constituent value (primarily cellulose and hemicellulose) than the original pulp. A growing chicken's ration containing 10% of the fermented product had a feed efficiency (2.14) similar to that of the standard ration (2.19) and was significantly better than that of the diet containing 10% of the original pulp (2.53). The difference observed in feed intake and weight gain between the standard diet and that with 10% of the fermented product is considered to be due to palatability factors which should be studied further.

  19. The use of lactoperoxidase for the bleaching of fluid whey.

    Science.gov (United States)

    Campbell, R E; Kang, E J; Bastian, E; Drake, M A

    2012-06-01

    Lactoperoxidase (LP) is the second most abundant enzyme in bovine milk and has been used in conjunction with hydrogen peroxide (H₂O₂) and thiocyanate (SCN⁻) to work as an antimicrobial in raw milk where pasteurization is not feasible. Thiocyanate is naturally present and the lactoperoxidase system purportedly can be used to bleach dairy products, such as whey, with the addition of very little H₂O₂ to the system. This study had 3 objectives: 1) to quantify the amount of H₂O₂ necessary for bleaching of fluid whey using the LP system, 2) to monitor LP activity from raw milk through manufacture of liquid whey, and 3) to compare the flavor of whey protein concentrate 80% (WPC80) bleached by the LP system to that bleached by traditional H₂O₂ bleaching. Cheddar cheese whey with annatto (15 mL of annatto/454 kg of milk, annatto with 3% wt/vol norbixin content) was manufactured using a standard Cheddar cheesemaking procedure. Various levels of H₂O₂ (5-100 mg/kg) were added to fluid whey to determine the optimum concentration of H₂O₂ for LP activity, which was measured using an established colorimetric method. In subsequent experiments, fat-separated whey was bleached for 1h with 250 mg of H₂O₂/kg (traditional) or 20 mg of H₂O₂/kg (LP system). The WPC80 was manufactured from whey bleached with 250 mg of H₂O₂/kg or 20mg of H₂O₂/kg. All samples were subjected to color analysis (Hunter color values and norbixin extraction) and proximate analysis (fat, protein, and moisture). Sensory and instrumental volatile analyses were conducted on WPC80. Optimal LP bleaching in fluid whey occurred with the addition of 20mg of H₂O₂/kg. Bleaching of fluid whey at either 35 or 50°C for 1 h with LP resulted in > 99% norbixin destruction compared with 32 or 47% destruction from bleaching with 250 mg of H₂O₂/kg, at 35 or 50°C for 1 h, respectively. Higher aroma intensity and increased lipid oxidation compounds were documented in WPC80 from

  20. EUCALYPTUS CELLULOSE MICRO/NANOFIBRILS IN EXTRUDED FIBERCEMENT COMPOSITES

    Directory of Open Access Journals (Sweden)

    Camila Soares Fonseca

    2016-03-01

    Full Text Available Extrusion is an alternative process for fiber-cement production and allows many advantages such as different geometries for the extruded products and the low initial investment for industrial production. In this context the aim of this study was to produce cellulose micro/nanofibrils from Eucalyptus pulp and evaluate the properties of cementitious composites made with different contents of cellulose micro/nanofibrils. Cellulose micro/ nanofibrils were produced using a mechanical defibrillator, and characterized for their morphology. Extruded composites were produced with 0.5 to 1.0% (by mass of micro/ nanofibrils and compared to unreinforced composites. Composites reinforced with 1.0% of micro/nanofibrils presented higher water absorption and apparent porosity than their counter parts. No significant differences were observed for modulus of rupture (MOR, limit of proportionality (LOP and final specific deformation, between the composites reinforced with 0.5% and 1.0% of micro/nanofibrils and those with no reinforcement. The static elastic modulus (MOE increased and specific energy decreased with the inclusion of 1.0% of micro/nanofibrils. Dynamic elastic modulus (E of the composites increased with the increase of micro/nanofibrils content and of weathering exposition. This study indicates that fiber-cements are sensitive to changes in structural composition and time of ageing (135 days. This information can be useful for developing of new products based on cellulose micro/nanofibrils.

  1. Prospects for biodiesel as a byproduct of wood pulping - A review

    Directory of Open Access Journals (Sweden)

    Hubbe, M. A.

    2006-07-01

    Full Text Available Effective utilization of byproducts can affect the profitability of kraft pulping to produce cellulosic fibers from wood. This review considers opportunities to use tall oil components, obtained from kraft pulping, as a source of raw material for biodiesel fuel, or as a source of additives for petrodiesel. Considerable progress has been achieved with respect to converting vegetable oils to diesel fuel, and some of what has been learned appears to have potential application for processing of wood-derived fatty acids and related compounds. Alkaline-catalyzed transesterification strategies, while seemingly well adapted for relatively pure vegetable oil source materials, may not be the best fit for the processing of tall oil fractions. The promising strategies to consider include acid-catalyzed esterification, enzymatic processes, hydrogenation, and the use of supercritical methanol.

  2. Comparative culturing of Pleurotus spp. on coffee pulp and wheat straw: biomass production and substrate biodegradation.

    Science.gov (United States)

    Salmones, Dulce; Mata, Gerardo; Waliszewski, Krzysztof N

    2005-03-01

    The results of the cultivation of six strains of Pleurotus (P. djamor (2), P. ostreatus (2) and P. pulmonarius (2)) on coffee pulp and wheat straw are presented. Metabolic activity associated with biomass of each strain was determined, as well as changes in lignin and polysaccharides (cellulose and hemicellulose), phenolic and caffeine contents in substrate samples colonized for a period of up to 36 days. Analysis were made of changes during the mycelium incubation period (16 days) and throughout different stages of fructification. Greater metabolic activity was observed in the wheat straw samples, with a significant increase between 4 and 12 days of incubation. The degradation of polysaccharide compounds was associated with the fruiting stage, while the reduction in phenolic contents was detected in both substrates samples during the first eight days of incubation. A decrease was observed in caffeine content of the coffee pulp samples during fruiting stage, which could mean that some caffeine accumulates in the fruiting bodies.

  3. Production of furans from pulp sheet over sulfated solid acid catalysts

    Directory of Open Access Journals (Sweden)

    Hongdan Zhang

    2012-11-01

    Full Text Available Furans are high value-added biomass-derived chemicals that can be used to replace petrochemicals. In this study, sulfated solid acid catalysts were prepared by precipitation and impregnation and were used for the conversion of a cellulosic pulp sheet into furans. The physicochemical properties of the prepared sulfated solid acid with different calcination temperatures and different mol ratios of Ti-Al were characterized using XRD, elemental analysis, TG, and NH3-TPD. Furthermore, the effects of various processing parameters such as temperature, time, and catalyst dosage on the reaction performance were studied. The combined yield of 5-hydroxymethyl-furfural and furfural reached 8.9% and 4.5% of pulp sheet mass with a 5% dosage of SO42-/TiO2-Al2O3 catalyst at 220 oC for 30 min. The activity for recovered catalyst was also investigated in this study.

  4. Evaluation of peanut hulls as an alternative to bleaching clays

    Energy Technology Data Exchange (ETDEWEB)

    Hassanein, M. M.; El-Shami, S. M.; Taha, F. S.

    2011-07-01

    Peanut hulls (PNH) were carbonized at different temperatures, times, and evaluated at different concentrations as an alternative to bleaching clays. Evaluation of bleached crude soybean oil with PNH was based on their delta free fatty acids, reduction in peroxide value (PV), reduction in phospholipids (PL) and bleachability. The performance of several commercially used bleaching clays was evaluated, for comparison. Mixtures were formulated including: PNH and Tonsil -N (TN), PNH and Fuller's earth (FE) and PNH and O-passive (OP) and examined. The oxidative stability of oils was determined. Results for the investigated commercial bleaching clays revealed: TN > FE > F > TF > OP. Highest reduction in PV and PL, and highest bleachability were achieved for soybean oil bleached with 2% PNH carbonized at 500 degree centigrade for 30 min (PNH). Mixtures of PNH with the three chosen bleaching clays indicated that 1PNH : 2TN gave the highest bleachability. CSO was miscella bleached in hexane using PNH and resulted in an appreciable improvement in all oil characteristics, especially in bleachability. Oxidative stability of oils was in the following order: TN > control > FE > PNH with Induction period values of 23.1 > 6.43 > 5.73 > 2.85 h, respectively. (Author) 20 refs.

  5. Photoresponsive Cellulose Nanocrystals

    Directory of Open Access Journals (Sweden)

    Dimitris S Argyropoulos

    2011-07-01

    Full Text Available In this communication a method for the creation of fluorescent cellulose nanoparticles using click chemistry and subsequent photodimerization of the installed side‐ chains is demonstrated. In the first step, the primary hydroxyl groups on the surface of the CNCs were converted to carboxylic acids by using TEMPO‐mediated hypohalite oxidation. The alkyne groups, essential for the click reaction, were introduced into the surface of TEMPO‐ oxidized CNCs via carbodiimide‐mediated formation of an amide linkage between monomers carrying an amine functionality and carboxylic acid groups on the surface of the TEMPO‐oxidized CNCs. Finally, the reaction of surface‐modified TEMPO‐oxidized cellulose nanocrystals and azido‐bearing coumarin and anthracene monomers were carried out by means of a click chemistry, i.e., Copper(I‐catalyzed Azide‐Alkyne Cycloaddition (CuAAC to produce highly photo‐responsive and fluorescent cellulose nanoparticles. Most significantly, the installed coumarin and/or anthracene side‐chains were shown to undergo UV‐induced [2+2] and [4+4] cycloaddition reactions, bringing and locking the cellulose nanocrystals together. This effort paves the way towards creating, cellulosic photo responsive nano‐arrays with the potential of photo reversibility since these reactions are known to be reversible at varying wavelengths.

  6. Titanium dioxide–cellulose hybrid nanocomposite and its glucose biosensor application

    International Nuclear Information System (INIS)

    Highlights: ► An organic–inorganic hybrid nanocomposite was fabricated by blending TiO2 nanoparticles and cellulose solution. ► The hybrid nanocomposite has advantages of biodegradability and bio-compatibility of cellulose and physical properties of TiO2. ► Enzyme glucose oxidase (GOx) was immobilized into the hybrid nanocomposite and covalent bonding between TiO2 and GOx was confirmed by X-ray photoelectron analysis. ► Linear response of the glucose biosensor was obtained in the range of 1–10 mM. - Abstract: This paper investigates the fabrication of titanium dioxide (TiO2)–cellulose hybrid nanocomposite and its possibility for a conductometric glucose biosensor. TiO2 nanoparticles were blended with cellulose solution prepared by dissolving cotton pulp with lithium chloride/N,N-dimethylacetamide solvent to fabricate TiO2–cellulose hybrid nanocomposite. The enzyme, glucose oxidase (GOx) was immobilized into this hybrid nanocomposite by physical adsorption method. The successful immobilization of glucose oxidase into TiO2–cellulose hybrid nanocomposite via covalent bonding between TiO2 and GOx was confirmed by X-ray photoelectron analysis. The linear response of the glucose biosensor is obtained in the range of 1–10 mM. This study demonstrates that TiO2–cellulose hybrid nanocomposite can be a potential candidate for an inexpensive, flexible and disposable glucose biosensor.

  7. Intrapulpal temperature variation during bleaching with various activation mechanisms

    Directory of Open Access Journals (Sweden)

    Sílvia Masae de Araujo Michida

    2009-10-01

    Full Text Available OBJECTIVES: The aim of this study was to evaluate the intrapulpal temperature variation after bleaching treatment with 35% hydrogen peroxide using different sources of activation. MATERIAL AND METHODS: Twenty-four human teeth were sectioned in the mesiodistal direction providing 48 specimens, and were divided into 4 groups (n=12: (G1 Control - Bleaching gel without light activation, (G2 Bleaching gel + halogen light, (G3 Bleaching gel + LED, (G4 Bleaching gel + Nd:YAG Laser. The temperatures were recorded using a digital thermometer at 4 time points: before bleaching gel application, 1 min after bleaching gel application, during activation of the bleaching gel, and after the bleaching agent turned from a dark-red into a clear gel. Data were analyzed statistically by the Dunnet's test, ANOVA and Tukey's test (a=0.05. RESULTS: The mean intrapulpal temperature values (ºC in the groups were: G1: 0.617 ± 0.41; G2: 1.800 ± 0.68; G3: 0.975 ± 0.51; and G4: 4.325 ± 1.09. The mean maximum temperature variation (MTV values were: 1.5ºC (G1, 2.9ºC (G2, 1.7ºC (G3 and 6.9ºC (G4. When comparing the experimental groups to the control group, G3 was not statistically different from G1 (p>0.05, but G2 and G4 presented significantly higher (p<0.05 intrapulpal temperatures and MTV. The three experimental groups differed significantly (p<0.05 from each other. CONCLUSIONS: The Nd:YAG laser was the activation method that presented the highest values of intrapulpal temperature variation when compared with LED and halogen light. The group activated by LED light presented the lowest values of temperature variation, which were similar to that of the control group.

  8. Cassava Peels for Alternative Fibre in Pulp and Paper Industry: Chemical Properties and Morphology Characterization

    Directory of Open Access Journals (Sweden)

    Ashuvila Mohd Aripin

    2013-11-01

    Full Text Available Without a proper waste management, the organic wastes such as cassava peels could result in increased amount of solid waste dump into landfill. This study aims to use non-wood organic wastes as pulp for paper making industries; promoting the concept of ‘from waste to wealth and recyclable material’. The objective  of this study is to determine the potential of casssava peel as alternative fibre in pulp and paper based on its chemical properties and surface morphology characteristic. Quantified parameters involved are holocellulose, cellulose, hemicellulose, lignin, one percent of sodium hydroxide, hot water solubility and ash content. The chemical characterization was in accordance with relevant TAPPI Test, Kurscher-Hoffner and Chlorite methods. Scanning electron microscopy (SEM was used to observe and determine the morphological characteristic of untreated cassava peels fibre. In order to propose the suitability of the studied plant as an alternative fibre resource in pulp and paper making, the obtained results are compared to other published literatures especially from wood sources. Results indicated that the amount of holocellulose contents in cassava peels (66% is the lowest than of wood (70 - 80.5% and canola straw (77.5%; however this value is still within the limit suitability to produce paper. The lignin content (7.52% is the lowest than those of all wood species (19.9-26.22%. Finally, the SEM images showed that untreated cassava peel contains abundance fibre such as hemicellulose and cellulose that is hold by the lignin in it. In conclusion, chemical properties and morphological characteristics of cassava peel indicated that it is suitable to be used as an alternative fibre sources for pulp and paper making industry, especially in countries with limited wood resources

  9. A bleaching earth from egyptian local deposits

    Directory of Open Access Journals (Sweden)

    El Kinawy, Omayma S.

    2001-10-01

    Full Text Available The present investigation deals with the bleaching of vegetable oils using activated clays collected from some deposits in Egypt as compared to Tonsil FF currently used by local oil industry. The comparison was made; not only on the basis of the decolourising power of the earth, but also on the basis of its effects on the oil acidity, formation of the oil peroxides and the decomposition rate of the formed peroxides to aldehydes and ketones during the bleaching process. The activation of the collected earth samples was made using 4N HCl, 6N HCl and 30 % H2SO4. The bleaching tests of the activated samples were performed using the major four oil types processed in Egypt being cottonseed, sunflower, soybean and palm oils. In addition to the laboratory-evaluation tests, the performance of the activated samples, which showed promise on the lab-scale have been also tested on an industrial scale. The industrial application has proved that the activated local earth's can be successfully used as bleaching earth of local oils. Thus it can be used as a substitute of the varieties currently imported and used by the local oil sector.La presente investigación trata de la decoloración de aceites vegetales usando tierras activadas obtenidas de yacimientos egipcios, comparándola con el Tonsil FF usado normalmente en la industria oleícola local. La comparación se realizó, no sólo sobre la base del poder decolorante de la tierra, sino también sobre la base de sus efectos en la acidez del aceite, la formación de peróxidos y la velocidad de descomposición de los peróxidos formados en aldehidos y cetonas durante el proceso de decoloración. La activación de las muestras de tierras recogidas se hizo utilizando ClH 4N, ClH 6N y H2SO4 30 %. Los tests de decoloración de las muestras activadas se llevaron a cabo usando los cuatro tipos mayoritarios de aceites procesados en Egipto: aceite de semilla de algodón, de girasol, de soja y de palma. Además de los

  10. FRAP analysis: accounting for bleaching during image capture.

    Directory of Open Access Journals (Sweden)

    Jun Wu

    Full Text Available The analysis of Fluorescence Recovery After Photobleaching (FRAP experiments involves mathematical modeling of the fluorescence recovery process. An important feature of FRAP experiments that tends to be ignored in the modeling is that there can be a significant loss of fluorescence due to bleaching during image capture. In this paper, we explicitly include the effects of bleaching during image capture in the model for the recovery process, instead of correcting for the effects of bleaching using reference measurements. Using experimental examples, we demonstrate the usefulness of such an approach in FRAP analysis.

  11. A method for detecting MFO induction by Japanese pulp mill effluents with chick embryo

    Energy Technology Data Exchange (ETDEWEB)

    Tatarazako, Norihisa; Kamaya, Yasushi [Japan Pulp and Paper Research Inst. Inc., Tokodai, Tsukuba (Japan)

    1995-12-31

    As a biomarker of physiological responses in fish exposed to pulp and paper mill effluents, mixed function oxygenase (MFO) induction has been investigated by many researchers. The induction and/or inhibition of MFOs is generally affected by various factors of fish such as species, maturity, sex, size and spawning status, and by other environmental variables. Therefore, the method demands technical skills to get a constant result. In addition, the test is costly and also time consuming. In this paper, the authors propose a MFOs induction method using chick embryo, instead of fish, for the assessment of pulp mill effluent. The merits of this method are as follows; inexpensive and commercially available test organisms, easy maintenance of the organisms, no feeding, high uniformity of the developing stage, sensitive responses to xenobiotics, low sample volume requirements, easy testing of various samples at one time and minimal training. P450 1A1 has been found in the microsome of chick embryo. Metabolic function of the P450 1A1 can be regarded basically the same as that of fish. Small amount of xenobiotics, about 100 {micro}l, were injected into the air chamber of 16-day-old chick embryos. Liver microsomes were isolated 48 h after administration. Ethoxyresorufin-O-deethylase (EROD) activity was determined by the direct fluorimetric method. Using the chick embryo method, the authors analyzed various chloro-organics, model bleached kraft pulp mill effluents, model black liquor and several total effluents of Japanese pulp mills. Methylcholanthrene and 2,3,7,8-TCDD were used as positive controls. In this paper, the authors will report the details of the chick embryo method and also some results of the assessment using the method.

  12. [Endodontic treatment of primary teeth. Pulp exposure and pulp necrosis].

    Science.gov (United States)

    Gruythuysen, R J M

    2005-11-01

    With management of the deep caries in primary teeth we have to take account into the coping strategies of the patient and the state of the development of the dentition. That's why in most cases a root canal treatment of primary incisors or even a pulpotomy is not indicated. Often Intellectual Decision Not To Restore is a good alternative for treatment of deep caries in primary incisors. In deep caries lesions of primary canines and molars preferably minimal invasive techniques as indirect pulp capping are performed. In case of a exposure, the dentist can choose between several types of treatment. Improved techniques have lead to clinical satisfying results of the calcium hydroxide pulpotomy. A partial pulpotomy is if possible the treatment of choice. A resin modified glass ionomer cement is used to cover the pulp wound because it has good sealing properties and it is easy to handle. To limit the burden in young children a root canal treatment in primary teeth is seldom indicated. Overfilling with calcium hydroxide in root canal treatment of primary teeth never causes problems. PMID:16320568

  13. The cellulose resource matrix.

    Science.gov (United States)

    Keijsers, Edwin R P; Yılmaz, Gülden; van Dam, Jan E G

    2013-03-01

    The emerging biobased economy is causing shifts from mineral fossil oil based resources towards renewable resources. Because of market mechanisms, current and new industries utilising renewable commodities, will attempt to secure their supply of resources. Cellulose is among these commodities, where large scale competition can be expected and already is observed for the traditional industries such as the paper industry. Cellulose and lignocellulosic raw materials (like wood and non-wood fibre crops) are being utilised in many industrial sectors. Due to the initiated transition towards biobased economy, these raw materials are intensively investigated also for new applications such as 2nd generation biofuels and 'green' chemicals and materials production (Clark, 2007; Lange, 2007; Petrus & Noordermeer, 2006; Ragauskas et al., 2006; Regalbuto, 2009). As lignocellulosic raw materials are available in variable quantities and qualities, unnecessary competition can be avoided via the choice of suitable raw materials for a target application. For example, utilisation of cellulose as carbohydrate source for ethanol production (Kabir Kazi et al., 2010) avoids the discussed competition with easier digestible carbohydrates (sugars, starch) deprived from the food supply chain. Also for cellulose use as a biopolymer several different competing markets can be distinguished. It is clear that these applications and markets will be influenced by large volume shifts. The world will have to reckon with the increase of competition and feedstock shortage (land use/biodiversity) (van Dam, de Klerk-Engels, Struik, & Rabbinge, 2005). It is of interest - in the context of sustainable development of the bioeconomy - to categorize the already available and emerging lignocellulosic resources in a matrix structure. When composing such "cellulose resource matrix" attention should be given to the quality aspects as well as to the available quantities and practical possibilities of processing the

  14. The cellulose resource matrix.

    Science.gov (United States)

    Keijsers, Edwin R P; Yılmaz, Gülden; van Dam, Jan E G

    2013-03-01

    The emerging biobased economy is causing shifts from mineral fossil oil based resources towards renewable resources. Because of market mechanisms, current and new industries utilising renewable commodities, will attempt to secure their supply of resources. Cellulose is among these commodities, where large scale competition can be expected and already is observed for the traditional industries such as the paper industry. Cellulose and lignocellulosic raw materials (like wood and non-wood fibre crops) are being utilised in many industrial sectors. Due to the initiated transition towards biobased economy, these raw materials are intensively investigated also for new applications such as 2nd generation biofuels and 'green' chemicals and materials production (Clark, 2007; Lange, 2007; Petrus & Noordermeer, 2006; Ragauskas et al., 2006; Regalbuto, 2009). As lignocellulosic raw materials are available in variable quantities and qualities, unnecessary competition can be avoided via the choice of suitable raw materials for a target application. For example, utilisation of cellulose as carbohydrate source for ethanol production (Kabir Kazi et al., 2010) avoids the discussed competition with easier digestible carbohydrates (sugars, starch) deprived from the food supply chain. Also for cellulose use as a biopolymer several different competing markets can be distinguished. It is clear that these applications and markets will be influenced by large volume shifts. The world will have to reckon with the increase of competition and feedstock shortage (land use/biodiversity) (van Dam, de Klerk-Engels, Struik, & Rabbinge, 2005). It is of interest - in the context of sustainable development of the bioeconomy - to categorize the already available and emerging lignocellulosic resources in a matrix structure. When composing such "cellulose resource matrix" attention should be given to the quality aspects as well as to the available quantities and practical possibilities of processing the

  15. A novel method for preparing microfibrillated cellulose from bamboo fibers

    Science.gov (United States)

    Dat Nguyen, Huu; Thanh Thuy Mai, Thi; Bich Nguyen, Ngoc; Duy Dang, Thanh; Loan Phung Le, My; Dang, Tan Tai; Tran, Van Man

    2013-03-01

    The bamboo fiber is a potential candidate for biomass and power source application. In this study, microfibrillated cellulose (MFC) is prepared from raw fibers of bamboo tree (Bambusa Blumeana J A & J H Schultes) by an alkali treatment at room temperature in association with a bleaching treatment followed by a sulfuric acid hydrolysis. Field-emission scanning electron microscopy (FESEM) images indicated that final products ranged from 20 to 40 nm in diameter. The chemical composition measurement and Fourier transform infrared (FTIR) spectroscopy showed that both hemicellulose and lignin are mostly removed in the MFC. The x-ray diffraction (XRD) results also show that MFC has crystallinity of more than 70%. The thermogravimetric analysis (TGA) curves revealed that cellulose microfibers have a two-step thermal decomposition behavior owing to the attachment of sulfated groups onto the cellulose surface in the hydrolysis process with sulfuric acid. The obtained MFCs may have potential applications in alternative power sources as biomass, in pharmaceutical and optical industries as additives, as well as in composite fields as a reinforcement phase.

  16. Characterization of sugar beet pulp derived oligosaccharides

    NARCIS (Netherlands)

    Leijdekkers, M.

    2015-01-01

    Abstract This thesis aimed at characterizing complex mixtures of sugar beet pulp derived oligosaccharides, in order to be able to monitor and optimize the enzymatic saccharification of sugar beet pulp. Hydrophilic interaction chromatography with on-line evaporative light scattering

  17. PULP DEMAND IN THE INTERNATIONAL MARKET

    Directory of Open Access Journals (Sweden)

    Edmilson Santos Cruz

    2003-01-01

    Full Text Available This study aimed at analyzing the international pulp market, taking into account themain exporting countries and importing regions, with the objective of estimating, for each market, theown-price and cross-price elasticity in relation to the demand of the pulp, differentiated for country oforigin. The model considers that imports are differentiated by origin; therefore they are not perfect substitutes. The demand from Europe, North America and the Rest of the World for the pulp from theUnited States,Canada, Sweden, Finland, Portugal and Brazil was inelastic. The Asian demand for thissome pulp was elastic. Europe and the Rest of the World showed negative cross-price elasticity, i. e.,and the imported pulp from other countries are complementary products. North America and Asiashowed positive crow-price elasticity, i. e., they consider the pulp produced in other countries assubstitute products. The net effect of the variation on the price of pulp in a country h, over the amountof pulp that goes to the region i depends on the matching of values related to the elasticity ofsubstitution and the price elasticity of the total demand.

  18. 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

  19. Study of Melanin Bleaching After Immunohistochemistry of Melanin-containing Tissues

    OpenAIRE

    Shen, Hongwu; Wu, Wenqiao

    2015-01-01

    Melanin may interfere with immunohistochemical staining. The goal of this study was to investigate the effects of trichloroisocyanuric acid (TCCA) bleaching, potassium permanganate bleaching, and potassium dichromate bleaching on melanin, tissue antigen, and 3,3′-diaminobenzidine (DAB) using melanin-containing and melanin-free tissue samples. Our results demonstrated that all 3 bleaching methods efficiently bleached melanin and partially destroyed tissue antigen. In addition, potassium perman...

  20. Contrasting Patterns of Coral Bleaching Susceptibility in 2010 Suggest an Adaptive Response to Thermal Stress

    OpenAIRE

    James R Guest; Baird, Andrew H.; Maynard, Jeffrey A; Efin Muttaqin; Alasdair J Edwards; Stuart J Campbell; Katie Yewdall; Yang Amri Affendi; Loke Ming Chou

    2012-01-01

    BACKGROUND: Coral bleaching events vary in severity, however, to date, the hierarchy of susceptibility to bleaching among coral taxa has been consistent over a broad geographic range and among bleaching episodes. Here we examine the extent of spatial and temporal variation in thermal tolerance among scleractinian coral taxa and between locations during the 2010 thermally induced, large-scale bleaching event in South East Asia. METHODOLOGY/PRINCIPAL FINDINGS: Surveys to estimate the bleaching ...

  1. Post-bleaching application of an antioxidant on dentin bond strength of three dental adhesives

    OpenAIRE

    Maryam Khoroushi; Tahereh Saneie

    2012-01-01

    Background: Antioxidizing agents have recently been suggested to compensate decreased bond strength of resin materials to bleached tooth tissues. This study compared the shear bond strength (SBS) of three different adhesives on bleached dentin immediately after bleaching, bleached/delayed for 1 week, and bleached/applied antioxidizing agent. Materials and Methods: The dentinal surfaces of 132 intact extracted molars were prepared and divided into 12 groups. The following adhesives were in...

  2. The enzymatic hydrolysis of pretreated pulp fibers predominantly involves “peeling/erosion” modes of action

    Science.gov (United States)

    2014-01-01

    Background There is still considerable debate regarding the actual mechanism by which a “cellulase mixture” deconstructs cellulosic materials, with accessibility to the substrate at the microscopic level being one of the major restrictions that limits fast, complete cellulose hydrolysis. In the work reported here we tried to determine the predominant mode of action, at the fiber level, of how a cellulase mixture deconstructs pretreated softwood and hardwood pulp fibers. Quantitative changes in the pulp fibers derived from different pretreated biomass substrates were monitored throughout the course of enzymatic hydrolysis to see if the dominant mechanisms involved either the fragmentation/cutting of longer fibers to shorter fibers or their “peeling/delamination/erosion,” or if both cutting and peeling mechanisms occurred simultaneously. Results Regardless of the source of biomass, the type of pretreatment and the chemical composition of the substrate, under typical hydrolysis conditions (50°C, pH 4.8, mixing) longer pulp fibers (fiber length >200 μm) were rapidly broken down until a relatively constant fiber length of 130 to 160 μm was reached. In contrast, shorter fibers with an initial average fiber length of 130 to 160 μm showed no significant change in length despite their substantial hydrolysis. The fragmentation/cutting mode of deconstruction was only observed on longer fibers at early stages of hydrolysis. Although the fiber fragmentation mode of deconstruction was not greatly influenced by enzyme loading, it was significantly inhibited by glucose and was mainly observed during initial mixing of the enzyme and substrate. In contrast, significant changes in the fiber width occurred throughout the course of hydrolysis for all of the substrates, suggesting that fiber width may limit the rate and extent of cellulose hydrolysis. Conclusion It appears that, at the fiber level, pretreated pulp fibers are hydrolyzed through a two-step mode of action

  3. Biorefinery pulp mill - BiSe

    Energy Technology Data Exchange (ETDEWEB)

    Mielonen, K. [Lappeenranta University of Technology (Finland)], email: katriina.mielonen@lut.fi

    2012-07-01

    A need to utilize woody material in a more efficient way to produce pulp, biofuels and energy was seen as a key factor in the development of new pulp mill biorefineries. There are many alternatives to execute the biorefinery concept. In the Biorefinery Pulp Mill-project approached prehydrolysis of wood chips and acid hydrolysis of logging residue for the production of bioethanol, as well as the separation of lignin for the production of biodiesel were studied. The main goal of the project was to examine these new biofuel production methods and processes for the improvement of the competitiveness, energy effectiveness and economic profitability of domestic pulp mills, while keeping in mind the main product, chemical pulp.

  4. Anti-scaling agents in kraft pulping

    Directory of Open Access Journals (Sweden)

    Felissia, F. E.

    2007-05-01

    Full Text Available Scale formation in the digester during kraft pulping represents a great problem in pulp mills. Scaling reduces pulping control and efficiency, increasing energy costs and leading to cleaning breakdowns, with subsequent losses in productivity. The kraft process promotes CaCO3 scaling due to high calcium ion and carbonate concentrations, as well as high alkalinity and temperature levels, which increase the speed with which liquors reach a state of supersaturation. This work examines the action of diethylene triamine penta(methylene phosphonic acid (DTPMPA, either alone or combined with commercial anti-scaling agents, as an inhibitor of calcium carbonate precipitation in the kraft pulping of Pinus taeda. The theoretical amount of calcium deposited in the digester was obtained by mass balance. Soluble calcium was stable throughout cooking when using the phosphonates alone or combined with anti-scaling agents. When adding only DTPMPA, calcium stays in the pulp, rather than forming deposits.

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

    Science.gov (United States)

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

    2001-01-01

    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 efffluent/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 17??-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.

  6. Ecology: Deep and complex ways to survive bleaching

    Science.gov (United States)

    Pandolfi, John M.

    2015-02-01

    Mass coral bleaching events can drive reefs from being the domains of corals to becoming dominated by seaweed. But longitudinal data show that more than half of the reefs studied rebound to their former glory. See Letter p.94

  7. New Parameter for In-Office Dental Bleaching

    Science.gov (United States)

    Bortolatto, Janaina Freitas; de Carvalho, Priscila Petrucelli Freire; Trevisan, Tamara Carolina; Floros, Michael Christopher; Junior, Osmir Batista de Oliveira

    2016-01-01

    Dental bleaching is considered a conservative and biologically safe treatment for discolored teeth. Despite this, one of the major undesirable effects of bleaching is dentin sensitivity which may occur during and after treatment. To address these sensitivity issues, new dental bleaching preparations with lower concentrations of hydrogen peroxide (H2O2) have recently been introduced to the market. This paper presents a clinical case report of a 20-year-old female patient admitted to the Araraquara Dental School, UNESP, Brazil. The patient underwent dental bleaching using one of the new products with reduced hydrogen peroxide concentration, Lase Peroxide Lite 6%, a 6% H2O2 gel containing titanium oxide nanoparticles doped with nitrogen (6% H2O2/N-doped TiO2).

  8. New Parameter for In-Office Dental Bleaching.

    Science.gov (United States)

    Presoto, Cristina Dupim; Bortolatto, Janaina Freitas; de Carvalho, Priscila Petrucelli Freire; Trevisan, Tamara Carolina; Floros, Michael Christopher; Junior, Osmir Batista de Oliveira

    2016-01-01

    Dental bleaching is considered a conservative and biologically safe treatment for discolored teeth. Despite this, one of the major undesirable effects of bleaching is dentin sensitivity which may occur during and after treatment. To address these sensitivity issues, new dental bleaching preparations with lower concentrations of hydrogen peroxide (H2O2) have recently been introduced to the market. This paper presents a clinical case report of a 20-year-old female patient admitted to the Araraquara Dental School, UNESP, Brazil. The patient underwent dental bleaching using one of the new products with reduced hydrogen peroxide concentration, Lase Peroxide Lite 6%, a 6% H2O2 gel containing titanium oxide nanoparticles doped with nitrogen (6% H2O2/N-doped TiO2). PMID:27375906

  9. Through bleaching and tsunami: Coral reef recovery in the Maldives.

    Science.gov (United States)

    Morri, Carla; Montefalcone, Monica; Lasagna, Roberta; Gatti, Giulia; Rovere, Alessio; Parravicini, Valeriano; Baldelli, Giuseppe; Colantoni, Paolo; Bianchi, Carlo Nike

    2015-09-15

    Coral reefs are degrading worldwide, but little information exists on their previous conditions for most regions of the world. Since 1989, we have been studying the Maldives, collecting data before, during and after the bleaching and mass mortality event of 1998. As early as 1999, many newly settled colonies were recorded. Recruits shifted from a dominance of massive and encrusting corals in the early stages of recolonisation towards a dominance of Acropora and Pocillopora by 2009. Coral cover, which dropped to less than 10% after the bleaching, returned to pre-bleaching values of around 50% by 2013. The 2004 tsunami had comparatively little effect. In 2014, the coral community was similar to that existing before the bleaching. According to descriptors and metrics adopted, recovery of Maldivian coral reefs took between 6 and 15years, or may even be considered unachieved, as there are species that had not come back yet. PMID:26228070

  10. 工业大麻全秆制浆中试生产%A Trial Production of Whole Industrial Hemp Pulping

    Institute of Scientific and Technical Information of China (English)

    关庆芳; 孙川

    2012-01-01

    在前期工业大麻秆芯制浆以及大麻全秆小试制浆的基础上,对大麻全秆制浆进行了中试生产实践。结果表明:大麻全秆易蒸煮,纸浆得率较高、易漂白,聚戊糖含量适中、灰分低,易润胀打浆。蒸煮黑液含硅量比草类原料(如麦草)黑液低得多,且漂白时污染轻.%On the basis of the pulping of industrial hemp stem and lab experiment for whole industrial hemp pulping. The experimental showed that whole industrial hemp has advantages of easy cooking, easy bleaching, high pulping yield, low dioxines compaerd by lignin and chlorine in the process of bleaching, low pollution, moderate content of pentosen, easy swelling and beating. Besides, low ash content, and its silicon conent from black liquor is much lower than the silicon conent from grasses material black liquor such as wheat straw.

  11. Effect of titanium dioxide and 3.5% hydrogen peroxide with 405-nm diode laser irradiation on bonding of resin to pulp chamber dentin

    Science.gov (United States)

    Haruyama, A.; Kato, J.; Kameyama, A.; Hirai, Y.; Oda, Y.

    2010-04-01

    This study was conducted to determine the effect of a 3.5% hydrogen peroxide solution containing titanium dioxide on bonding of resin to pulp chamber dentin. Extracted bovine anterior teeth were allocated to three groups of ten teeth each. The coronal labial pulp chamber dentin was exposed and bleached with 3.5% hydrogen peroxide with titanium dioxide with 405-nm diode laser irradiation for 15 min (Group 1); 30% hydrogen peroxide with halogen lamp irradiation for 15 min (Group 2); and distilled water for 15 min (Group 3). After bleaching, the pulp chamber dentin was prepared for composite resin bonding and the interface between the resin and dentin was observed by scanning electron microscopy. The microtensile bond strength (μTBS) and failure patterns were determined. The μTBS values (mean ± SD) were: 17.28 ± 5.79 MPa ( n = 36), 0 MPa, and 26.50 ± 9.83 MPa ( n = 36) in Groups 1, 2, and 3, respectively. The μTBS in Group 3 was significantly higher than that in Group 1 ( P < 0.05). Hybrid layers and resin tags were clearly observed at the interface in Groups 1 and 3, but not in Group 2. Adhesive failure was mainly observed in Group 1, whereas dentin failure was the main failure pattern in Group 3.

  12. The effects of pulp mill effluent on the sex steroid binding protein in white sucker (Catostomus commersoni) and longnose sucker (C catostomus).

    Science.gov (United States)

    Pryce-Hobby, A C; McMaster, M E; Hewitt, L M; Van Der Kraak, G

    2003-02-01

    The objective of this study was to characterize the effects of pulp mill effluent on the properties of the sex steroid binding protein (SBP) in the plasma of white sucker (Catostomus commersoni) and longnose sucker (C. catostomus). SBPs which specifically bind estradiol and testosterone with high affinity (k(D) approximately 3 nM) and low capacity (B(max) approximately 73-81 nM) were identified in both species. Subsequent studies determined if the properties of the SBP in white sucker exposed to bleached kraft mill effluent (BKME) at Terrace Bay, ON, and in longnose sucker exposed to BKME at Grande Prairie, AB. differed from appropriate reference fish. There were no effects of BKME exposure on the binding affinity (k(D)) of the SBP in either species, but there was a significant increase in the binding capacity (B(max)) of longnose sucker SBP exposed to BKME. The livers of nai;ve white sucker exposed to effluent at Terrace Bay or a bleached sulfite/groundwood mill in Edmundston, NB, rapidly accumulated compounds of differing hydrophobicity that bound to both the white sucker and goldfish (Carassius auratus) SBP. Conversely, there was reduced accumulation of SBP ligands in the bile of effluent-exposed fish. We have demonstrated that constituents present within pulp mill effluent bind to both the white sucker and goldfish SBP, and that native species residing downstream of pulp mill effluents may experience modifications in the properties of their SBP. PMID:12600684

  13. CHARACTERIZATION OF REGENERATED CELLULOSE MEMBRANES HYDROLYZED FROM CELLULOSE ACETATE

    Institute of Scientific and Technical Information of China (English)

    Yun Chen; Xiao-peng Xiong; Guang Yang; Li-na Zhang; Sen-lin Lei; Hui Lianga

    2002-01-01

    A series of cellulose acetate membranes were prepared by using formamide as additive, and then were hydrolyzedin 4 wt% aqueous NaOH solution for 8 h to obtain regenerated cellulose membranes. The dependence of degree ofsubstitution, structure, porous properties, solubility and thermal stability on hydrolysis time was studied by chemical titration,Fourier transform infrared spectroscopy, scanning electron microscopy, wide-angle X-ray diffraction, and differentialscanning calorimetry, respectively. The results indicated that the pore size of the regenerated cellulose membranes wasslightly smaller than that of cellulose acetate membrane, while solvent-resistance, crystallinity and thermostability weresignificantly improved. This work provides a simple way to prepare the porous cellulose membranes, which not only kept thegood pore characteristics of cellulose acetate membranes, but also possessed solvent-resistance, high crystallinity andthermostability. Therefore, the application range of cellulose acetate membranes can be expanded.

  14. Pulping byproducts as sacrificial agents in enhanced oil recovery by micellar flooding

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, J.S. Jr.; Westmoreland, C.G.

    1984-01-01

    A substantial bar to implementation of enhanced oil recovery by injection of surfactant formulations is the cost of large volumes of the chemicals. A large fraction of the chemicals is lost by adsorption on the minerals in oil-bearing formations or by precipitation by ions in the connate water or displaced from the minerals. Besides the cost, losses make difficult control of the intricate chemistry needed for optimal conditions. Cheap chemicals which would modify the formation by adsorbing competitively on the formation or by sequestering interfering ions could be important in advancing the approach. Substances generated in the pulping of wood by the kraft process are of possible interest, and evaluations of several are presented here. Of these, sodium saccharinate, caustic extract from bleaching, and weak black liquor seem promising.

  15. Insight in the Chemistry of Laser-Activated Dental Bleaching

    Directory of Open Access Journals (Sweden)

    Roeland Jozef Gentil De Moor

    2015-01-01

    Full Text Available The use of optical radiation for the activation of bleaching products has not yet been completely elucidated. Laser light is suggested to enhance the oxidizing effect of hydrogen peroxide. Different methods of enhancing hydrogen peroxide based bleaching are possible. They can be classified into six groups: alkaline pH environment, thermal enhancement and photothermal effect, photooxidation effect and direct photobleaching, photolysis effect and photodissociation, Fenton reaction and photocatalysis, and photodynamic effect.

  16. Insight in the Chemistry of Laser-Activated Dental Bleaching

    OpenAIRE

    Roeland Jozef Gentil De Moor; Jeroen Verheyen; Andrii Diachuk; Peter Verheyen; Maarten August Meire; Peter Jozef De Coster; Filip Keulemans; Mieke De Bruyne; Laurence James Walsh

    2015-01-01

    The use of optical radiation for the activation of bleaching products has not yet been completely elucidated. Laser light is suggested to enhance the oxidizing effect of hydrogen peroxide. Different methods of enhancing hydrogen peroxide based bleaching are possible. They can be classified into six groups: alkaline pH environment, thermal enhancement and photothermal effect, photooxidation effect and direct photobleaching, photolysis effect and photodissociation, Fenton reaction and photocata...

  17. Conservation of Coral Reefs after the 1998 Global Bleaching Event

    OpenAIRE

    Hayes, R.L.; Goreau, T.J.; Mcclanahan, T.R.

    2000-01-01

    Large-scale coral bleaching has happened repeatedly in the Pacific and Indian oceans and the Caribbean since 1982. Previously it was observed only on a small scale (Williams and Bunkley- Williams 1990;Jokiel & Coles 1990; Glynn 1988, 1991; Goreau et al. 1993; Goreau & Hayes 1994, 1995). The 1998 bleaching event was globally the most extensive such event recorded except in the Caribbean and Central Pacific where a comparison of year-byyear temperature and bl...

  18. Endolithic algae: an alternative source of photoassimilates during coral bleaching.

    OpenAIRE

    Fine, Maoz; Loya, Yossi

    2002-01-01

    Recent reports of worldwide coral bleaching events leading to devastating coral mortality have caused alarm among scientists and resource managers. Differential survival of coral species through bleaching events has been widely documented. We suggest that among the possible factors contributing to survival of coral species during such events are endolithic algae harboured in their skeleton, providing an alternative source of energy. We studied the dynamics of photosynthetic pigment concentrat...

  19. Cysticercosis cellulose cutis

    Directory of Open Access Journals (Sweden)

    Inamadar Arun

    2001-01-01

    Full Text Available A woman aged 30 years with solitary lesion of cysticercosis cellulose cutis is reported. Cutaneous cysticerci are often a pointer to the involvement of internal organs. Our patient was a pure vegetarian so, probable mode of infection may be ingestion of contaminated vegetables, where the practice of using pig feces as manure is prevalent.

  20. The cellulose resource matrix

    NARCIS (Netherlands)

    Keijsers, E.R.P.; Yilmaz, G.; Dam, van J.E.G.

    2013-01-01

    The emerging biobased economy is causing shifts from mineral fossil oil based resources towards renewable resources. Because of market mechanisms, current and new industries utilising renewable commodities, will attempt to secure their supply of resources. Cellulose is among these commodities, where

  1. The effect of combined bleaching techniques on oral microbiota

    Directory of Open Access Journals (Sweden)

    Franz-Montan Michelle

    2009-01-01

    Full Text Available Aims : To evaluate the antimicrobial activity of 10% and 37% carbamide peroxide during dental bleaching in three different modes. Materials and Methods : This five-week double-blind randomized controlled trial included 32 volunteers assigned to four groups (n = 8. Each group received bleaching agents or placebo as an in-office and at-home treatment. The dental bleaching techniques were: In-office bleaching (37% carbamide peroxide: CP37; at-home bleaching (10% carbamide peroxide: CP10 and the association of both (CP37 and CP10. Saliva samples were collected right before (baseline, right after, 12 hours after, and seven days after the treatment. Counts of total microorganisms, Streptococci, and Mutans streptococci were carried out. Friedman test (α = 0.05 was used to compare the microorganism counts. Results : The number of the all oral microorganisms remained stable during all experiment. Conclusions : No bleaching agent (CP37, CP10 or the combination of both was able to reduce the oral microorganisms tested.

  2. 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

  3. Cellulose esters synthesized using a tetrabutylammonium acetate and dimethylsulfoxide solvent system

    Science.gov (United States)

    Yu, Yongqi; Miao, Jiaojiao; Jiang, Zeming; Sun, Haibo; Zhang, Liping

    2016-07-01

    Cellulose acetate (CA) and cellulose acetate propionate (CAP) were homogeneously synthesized in a novel tetrabutylammonium acetate/dimethyl sulfoxide (DMSO) solvent system, without any catalyst, at temperatures below 70 °C. The molecular structures of the cellulose esters (CEs) and distributions of the substituents in the anhydroglucose repeating units were determined using 13C cross-polarization magic angle spinning nuclear magnetic resonance spectroscopy, and the degree of substitution (DS) values were determined using 1H nuclear magnetic resonance spectroscopy. The structures of the CEs, regenerated cellulose (RC), and pulp were determined using Fourier transform infrared spectroscopy. The thermal properties of the products were determined using thermogravimetric analysis. The temperatures of initial decomposition of the CEs were up to 40 °C higher than those of the RC and pulp. All the CEs were highly soluble in DMSO, but were insoluble in acetone. CAs with DS values less than 2.6 swelled or were poorly dissolved in CHCl3, but those with DS values above 2.9 dissolved rapidly. CAPs with DS values above 2.6 had good solubilities in ethyl acetate.

  4. High-yield pulping effluent treatment technologies

    International Nuclear Information System (INIS)

    The objective of this report is to examine the high-yield (mechanical) pulp processes with respect to environmental issues affected by the discharge of their waste streams. Various statistics are given that support the view that high-yield pulping processes will have major growth in the US regions where pulp mills are located, and sites for projects in the development phase are indicated. Conventional and innovative effluent-treatment technologies applicable to these processes are reviewed. The different types of mechanical pulping or high-yield processes are explained, and the chemical additives are discussed. The important relationship between pulp yield and measure of BOD in the effluent is graphically presented. Effluent contaminants are identified, along with other important characteristics of the streams. Current and proposed environmental limitations specifically related to mechanical pulp production are reviewed. Conventional and innovative effluent-treatment technologies are discussed, along with their principle applications, uses, advantages, and disadvantages. Sludge management and disposal techniques become an intimate part of the treatment of waste streams. The conclusion is made that conventional technologies can successfully treat effluent streams under current waste-water discharge limitations, but these systems may not be adequate when stricter standards are imposed. At present, the most important issue in the treatment of pulp-mill waste is the management and disposal of the resultant sludge

  5. Preparation and Characterization of Jute Cellulose Crystals-Reinforced Poly(L-lactic acid Biocomposite for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Mohammed Mizanur Rahman

    2014-01-01

    Full Text Available Crystalline cellulose was extracted from jute by hydrolysis with 40% H2SO4 to get mixture of micro/nanocrystals. Scanning electron microscope (SEM showed the microcrystalline structure of cellulose and XRD indicated the Iβ polymorph of cellulose. Biodegradable composites were prepared using crystalline cellulose (CC of jute as the reinforcement (3–15% and poly(lactic acid (PLA as a matrix by extrusion and hot press method. CC was cellulose derived from mercerized and bleached jute fiber by acid hydrolysis to remove the amorphous regions. FT-IR studies showed hydrogen bonding between the CC and the PLA matrix. The X-ray diffraction (XRD and differential scanning calorimetry (DSC studies showed that the percentage crystallinity of PLA in composites was found to be higher than that of neat PLA as a result of the nucleating ability of the crystalline cellulose. Furthermore, Vicker hardness and yield strength were found to increase with increasing cellulose content in the composite. The SEM images of the fracture surfaces of the composites were indicative of poor adhesion between the CC and the PLA matrix. The composite with 15% CC showed antibacterial effect though pure films but had no antimicrobial effect; on the other hand its cytotoxicity in biological medium was found to be medium which might be suitable for its potential biomedical applications.

  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. FIBRILLATION OF FLAX AND WHEAT STRAW CELLULOSE: EFFECTS ON THERMAL, MORPHOLOGICAL, AND VISCOELASTIC PROPERTIES OF POLY(VINYLALCOHOL/FIBRE COMPOSITES

    Directory of Open Access Journals (Sweden)

    Marta Hrabalova

    2011-03-01

    Full Text Available Nano-fibrillated cellulose was produced from flax and wheat straw cellulose pulps by high pressure disintegration. The reinforcing potential of both disintegrated nano-celluloses in a polyvinyl-alcohol matrix was evaluated. Disintegration of wheat straw was significantly more time and energy consuming. Disintegration did not lead to distinct changes in the degree of polymerization; however, the fibre diameter reduction was more than a hundredfold, creating a nano-fibrillated cellulose network, as shown through field-emission-scanning electron microscopy. Composite films were prepared from polyvinyl alcohol and filled with nano-fibrillated celluloses up to 40% mass fractions. Nano-fibrillated flax showed better dispersion in the polyvinyl alcohol matrix, compared to nano-fibrillated wheat straw. Dynamic mechanical analysis of composites revealed that the glass transition and rubbery region increased more strongly with included flax nano-fibrils. Intermolecular interactions between cellulose fibrils and polyvinyl alcohol matrix were shown through differential scanning calorimetry and attenuated total reflection-Fourier transform infrared spectroscopy. The selection of appropriate raw cellulose material for high pressure disintegration was an indispensable factor for the processing of nano-fibrillated cellulose, which is essential for the functional optimization of products.

  8. 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.

  9. On the beating of reinforcement pulp

    OpenAIRE

    Hiltunen, Eero

    2003-01-01

    The aim of this work was to gain a better understanding of the effect of reinforcement pulp beating on the strength of mechanical pulp-dominated paper. The main purpose of reinforcement pulp beating is to improve the runnability of paper. The first objective of this study was to maximize the runnability related strength properties by beating. It was assumed that the flaw-resisting ability of paper correlates with the runnability of the dry paper web. In-plane fracture properties were assumed ...

  10. Structure and mechanical properties of wet-spun fibers made from natural cellulose nanofibers.

    Science.gov (United States)

    Iwamoto, Shinichiro; Isogai, Akira; Iwata, Tadahisa

    2011-03-14

    Cellulose nanofibers were prepared by TEMPO-mediated oxidation of wood pulp and tunicate cellulose. The cellulose nanofiber suspension in water was spun into an acetone coagulation bath. The spinning rate was varied from 0.1 to 100 m/min to align the nanofibers to the spun fibers. The fibers spun from the wood nanofibers had a hollow structure at spinning rates of >10 m/min, whereas the fibers spun from tunicate nanofibers were porous. Wide-angle X-ray diffraction analysis revealed that the wood and tunicate nanofibers were aligned to the fiber direction of the spun fibers at higher spinning rates. The wood spun fibers at 100 m/min had a Young's modulus of 23.6 GPa, tensile strength of 321 MPa, and elongation at break of 2.2%. The Young's modulus of the wood spun fibers increased with an increase in the spinning rate because of the nanofiber orientation effect. PMID:21302950

  11. Enhancement of the nanofibrillation of wood cellulose through sequential periodate-chlorite oxidation.

    Science.gov (United States)

    Liimatainen, Henrikki; Visanko, Miikka; Sirviö, Juho Antti; Hormi, Osmo E O; Niinimaki, Jouko

    2012-05-14

    Sequential regioselective periodate-chlorite oxidation was employed as a new and efficient pretreatment to enhance the nanofibrillation of hardwood cellulose pulp through homogenization. The oxidized celluloses with carboxyl contents ranging from 0.38 to 1.75 mmol/g could nanofibrillate to highly viscous and transparent gels with yields of 100-85% without clogging the homogenizer (one to four passes). On the basis of field-emission scanning electron microscopy images, the nanofibrils obtained were of typical widths of approximately 25 ± 6 nm. All of the nanofibrillar samples maintained their cellulose I crystalline structure according to wide-angle X-ray diffraction results, and the crystallinity index was approximately 40% for all samples. PMID:22512713

  12. STUDIES ON TUNG OIL COATED REGENERATED CELLULOSE FILMS WITH WATER-RESISTANCE

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lina; YAN Shanhong

    1995-01-01

    Regenerated cellulose films with water-resistance were obtained by an improved method of preparing cellulose cuoxam solution from pulps of agricultural wastes (linters,wheat straw,reed and Bamao). Experimental results showed that the mechanical properties of both the dry and wet films were excellent. Data from IR, SEM and tensile strength measurements implied that the significant improvement of water-resistance of the films was due to the cohesion between the thin Tung oil covers with hydrophobicity and the regenerated cellulose films. The films were completely biodegraded after being buried in soil for 100 days. The transmittance of the films derived from linter and reed in visible band range were 80-90%.

  13. Analysis of the efficiency of different materials used as cervical barrier in endogenous bleaching

    Directory of Open Access Journals (Sweden)

    Joel de Brito Gonçalves

    2008-01-01

    Full Text Available Objective: Evaluate the efficiency of three materials used for making the cervical buffer on the bleaching procedure. Methods: Thirty-six, recently extracted human canines were used, and divided into four experimental groups of nine replicas in each group. Group I was the control group, in which no sealing was done in the cervical region; Group II corresponded to the cervical buffer made by chemically activated glass ionomer cement (Vidrion R; in Group III resin-modified glass ionomer cement (Vitremer, 3M, Sumaré, Brazil was used as the cervical buffer; and in Group IV Coltosol temporary restorative cement was used. A paste of sodium perborateand 30% hydrogen peroxide was placed in the pulp chamber for seven days, followed by placement of a dye to evaluate microleakageafterwards. Results: The results obtained among the experimental groups were statistically significant. Conclusion: That Coltosol was the most effective material against leakage in the apical direction. Vitremer (3M, Sumaré, Brazil occupied the intermediate position among the groups, and Vidrion behave better than the control group only, therefore, with precarious sealing properties.

  14. HYDROPHOBIZATION OF BLEACHED SOFTWOOD KRAFT FIBERS VIA ADSORPTION OF ORGANO-NANOCLAY

    Directory of Open Access Journals (Sweden)

    Jieming Chen,

    2012-07-01

    Full Text Available Montmorillonite clay particles that had been prepared with an alklyl-ammonium surfactant were used to modify the moisture-sensitivity of bleached softwood kraft fibers through solvent exchange and adsorption methods. Moisture absorption and water uptake of the wood pulp fibers were significantly lower after the organo-nanoclay treatment. Thermal stability, surface energy, and surface morphology of the treated fibers were characterized using Thermogravimetric Analysis (TGA, Inverse Gas Chromatography (IGC, Scanning Electron Microscopy-Energy Dispersive X-ray Analysis (SEM-EDX, and Transmission Electron Microscopy (TEM imaging. The Fourier Transform Infrared (FT-IR spectral characteristics of the treated fibers were obtained to better understand the modified surface functional groups of the treated fibers. The treated bio-fibers had nano-scale surface roughness and a much reduced surface energy. The contact angle of water on the treated fiber mat was found to be higher than 160º. The thermal stability of the treated fibers was not affected by the modification.

  15. SEM evaluation of pulp reaction to different pulp capping materials in dog’s teeth

    OpenAIRE

    Asgary, Saeed; Parirokh, Masoud; Eghbal, Mohammad Jafar; Ghoddusi, Jamileh

    2007-01-01

    Introduction: This investigation evaluates the effects of mineral trioxide aggregate (MTA), calcium hydroxide (CH) and calcium enriched mixture (CEM) as pulp capping materials on dental pulp tissues. Materials and Methods: The experimental procedures were performed on eighteen intact dog canine teeth. The pulps were exposed. Cavities were randomly filled with CEM, MTA, or CH followed by glass ionomer filling. After 2 months, animals were sacrificed, each tooth was sectioned into halves, and t...

  16. Cellulose nanofiber extraction from grass by a modified kitchen blender

    Science.gov (United States)

    Nakagaito, Antonio Norio; Ikenaga, Koh; Takagi, Hitoshi

    2015-03-01

    Cellulose nanofibers have been used to reinforce polymers, delivering composites with strength that in some cases can be superior to that of engineering plastics. The extraction of nanofibers from plant fibers can be achieved through specialized equipment that demands high energy input, despite delivering extremely low yields. The high extraction cost confines the use of cellulose nanofibers to the laboratory and not for industrial applications. This study aims to extract nanofibers from grass by using a kitchen blender. Earlier studies have demonstrated that paper sheets made of blender-extracted nanofibers (after 5 min to 10 min of blending) have strengths on par with paper sheets made from commercially available cellulose nanofibers. By optimizing the design of the blender bottle, nanofibrillation can be achieved in shorter treatment times, reducing the energy consumption (in the present case, to half) and the overall extraction cost. The raw materials used can be extended to the residue straw of agricultural crops, as an alternative to the usual pulp fibers obtained from wood.

  17. Multi-scale Characterization of Cellulose TEMPO-Nanofiber Suspension

    Science.gov (United States)

    Mao, Yimin; Liu, Kai; Hsiao, Benjamin

    Cellulose nanofiber (CNF) suspensions were characterized at multiple length scales. CNF suspension was prepared by applying 2,2,6,6-tetramethyl-1- piperidinyloxy (TEMPO) oxidation method to dry wood pulp. TEMPO method was able to produce fine fibers with a cross section dimension being in the order of magnitude of several nanometers, and length being several hundred nanometers. The surface was negatively charged. Charge density was characterized by Zeta-potential measurement. Both small-angle X-ray (SAXS) and small-angle neutron (SANS) methods were employed to examine fiber dimensions in solution. Data fitting indicated that newly-developed ribbon model was able to capture the essence of CNF's geometry, which is also computationally economic. The rectangular-shaped cross section was consistent to cellulose's crystal structure; and was able to provide insights into how cellulose crystals were biologically synthesized and packed in nature. Multi-angle dynamic light scattering (DLS) was used to study CNF's diffusion properties. A strong scattering-angle dependence of auto-correlation function was observed. The characterization is useful to understanding suspension quality of CNF, and can provide guideline for follow-up research aimed for a variety of applications.

  18. Interactions of microfibrillated cellulose and cellulosic fines with cationic polyelectrolytes

    OpenAIRE

    Taipale, Tero

    2010-01-01

    The overall aim of this work was to produce and characterize different types of cellulosic fines and microfibrillated cellulose; to study their interactions with high molar mass cationic polyelectrolytes; and to demonstrate novel examples of their utilization. The work was performed, and its results discussed mainly from papermaking point of view, but the results are also well applicable in other fields of industry. Cellulosic fines are an essential component of papermaking fiber suspens...

  19. PEROXYACID ENHANCED OXYGEN DELIGNIFICATION OF KRAFT PULP

    Institute of Scientific and Technical Information of China (English)

    JianZhao; XuezhiLi; ShulanShi; HuirenHu

    2004-01-01

    Effect of peroxyacid (a mixture ofperoxymonosulfuric acid and peroxyacetic acid)pretreatment on oxygen delignification of kraft pulpfrom eucalyptus was studied, and the conditions ofpretreatment (e.g. DTPA charge, peroxyacid charge,pretreatment time, pretreatment temperature and pHvalue) were optimized. The results show thatperoxyacid pretreatment prior to oxygendelignification could enhance oxygen delignificationof kraft pulp, and result in selective delignificationand increased delignified-pulp brightness. Theoptimum conditions of peroxyacid pretreatment wereas follows: peroxyacid charge 3% (onperoxymonosulfuric acid), 60~C, 30min, 12% pulpconsistency, pH5.0. Pretreatment with 0.5%DTPAwas essential before peroxyacid pretreatment. Underthe optimum conditions, the degree of delignificationand brightness of final pulp were increased by 12.4%(from 44.9% to 57.3%) and 4.9%(ISO, from 54.0%to 58.9%) respectively while maintaining a similarviscosity of final pulps compared to single oxygendelignification.

  20. Cleaner Production of Wheat Straw Pulp

    Institute of Scientific and Technical Information of China (English)

    黄国林; 陈中胜; 张成芳

    2002-01-01

    A pulping method using NH4OH with less amount of KOH as cooking liquor on wheat straw was developed. KOH could reduce consumption of NH3 and cooking time for its strong alkalinity. The effects of various pulping conditions such as composition of cooking liquor, liquid-to-solid ratio, maximum temperature, cooking time to the maximum temperature and cooking time at the maximum temperature were studied. Experimental results indicated that the rate of delignification was 85.12( and the pulp yield was 49.65% under suitable pulping conditions. It looks promising to use black liquor containing nitrogen, phosphorus, potassium and organic substance as fertilizer resources for agricultural production. A new pattern of ecological cycling may be set up between paper industry and farming.