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Sample records for cellulose pulp bleaching

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

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    Lilian Borges Brasileiro

    2001-12-01

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

  2. 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....

  3. Modeling chlorine dioxide bleaching of chemical pulp

    OpenAIRE

    Tarvo, Ville

    2010-01-01

    This doctoral thesis deals with the phenomenon-based modeling of pulp bleaching. Previous bleaching models typically utilize one or two empirical correlations to predict the kinetics in kappa number development. Empirical correlations are simple to develop, but their parameters are often tied to the validation system. A major benefit of physico-chemical phenomenon models is that they are valid regardless of the reaction environment. Furthermore, modeling the bleaching processes at molecular l...

  4. 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.

  5. 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.

  6. Valorisation of by Products from Bleached Eucalyptus Kraft Pulp Mill

    Science.gov (United States)

    Silva, M. C.; Lopes, O. R.; Colodette, J. L.; Porto, A. O.; Rieumont, J.; Chaussy, D.; Belgacem, M. N.; Silva, G. G.

    2008-08-01

    Three industrial wastes arising from bleached hardwood kraft pulps, namely: unbleached screen rejects (USR), effluent treatment (ETW), and eucalyptus bark (EB) were analyzed with the aim of their possible valorization as an alternative source of cellulose. Their morphological properties were determined using MorFi apparatus. For this study the sample bleached kraft pulp, BKP, was analyzed as a reference. Lignin and carbohydrate contents were also quantified. These by-products were studied as such (i.e. without careful purification) because we intended to find rational and low-cost way of valorization. In fact any additional operation will induce an over cost. The results obtained indicate that these industrial wastes can be potential raw material in fibre-based applications (paper, composites…), since they contain a high proportion of cellulose with preserved fibrillar morphology. Some of these materials have low lignin and inorganic residue contents.

  7. Hemicellulases in the bleaching of chemical pulps.

    Science.gov (United States)

    Suurnäkki, A; Tenkanen, M; Buchert, J; Viikari, L

    1997-01-01

    Hemicellulase-aided bleaching is the first full-scale biotechnical application in the pulp and paper industry which truly exploits the unique specificity and safety of biocatalysts. Hemicellulases are used to modify the structure of xylan and glucomannan in pulp fibers in order to enhance the chemical delignification. This technology can be combined with various types of kraft pulping processes and bleaching sequences. The aims of the enzymatic treatment depend on the actual mill conditions, and may be related to environmental demands, reduction of chemical costs, or maintenance or even improvement of product quality. The technology is applied on the mill scale in several countries. This review describes the principles of the enzyme-aided bleaching, the composition of the fiber substrates, the basic enzymology involved, and the present knowledge of the mechanisms of the action of enzymes, as well as the practical results and advantages obtained on the laboratory and industrial scale.

  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. BLEACHING EUCALYPTUS PULPS WITH SHORT SEQUENCES

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    Flaviana Reis Milagres

    2011-03-01

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

  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. Nanofibrillated cellulose as paper additive in Eucalyptus pulps

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    Israel González

    2012-11-01

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

  12. HYDROGEN PEROXIDE BLEACHING OF CMP PULP USING MAGNESIUM HYDROXIDE

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    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.

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

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    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.

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

    Science.gov (United States)

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

    2010-01-01

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

  15. ECF AND TCF BLEACHING OF SECONDARY FIBER PULP

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    Gustavo Ventorim

    2009-09-01

    Full Text Available In this study, ECF and TCF bleaching processes were evaluated for the bleaching of a deinked mixed office waste (MOW pulp sample produced in a pilot plant. The sample was bleached by all processes to a target brightness of 78 % ISO minimum. The results were interpreted on the basis of chemical cost to reach the target brightness, bleaching yield and bleached pulp quality as measured by viscosity, fluorescence and b* color coordinate. Among the ECF sequences, the mosattractive was the DEDD which showed the lowest chemical cost and produced bleached pulp of high quality as measured by viscosity, fluorescence and b* coordinate. The best TCF sequence with ozone was the Q(PO(ZQ(PO which resulted in very high brightness ceiling. This sequence decreased moderately the pulp b* coordinate and viscosity and slightly its fluorescence. Among the TCF sequences without ozone the Q(POQ(PO was the most effective but showed poor flexibility with regard to brightness ceiling. This sequence had little effect on pulp viscosity, fluorescence and b* coordinate. For all three  bleaching processes, it was determined that process yield is negatively affected by hot alkaline stages such as O, P and (PO.

  16. Preparation of Cellulose Nanofibrils from Bamboo Pulp by Mechanical Defibrillation for Their Applications in Biodegradable Composites.

    Science.gov (United States)

    Guimarães, Mario; Botaro, Vagner Roberto; Novack, Kátia Monteiro; Neto, Wilson Pires Flauzino; Mendes, Lourival Marin; Tonoli, Gustavo H D

    2015-09-01

    There is a growing interest in cellulose nanofibrils from renewable sources for various industrial applications. However, there is a lack of information on cellulose arising from bamboo pulps. Nanofibrils from refined bamboo pulps, including bleached, unbleached, and unrefined/unbleached, were obtained by mechanical defibrillation for use in biodegradable composites. The influence of industrial processes, such as pulping and refining of unbleached pulps, as well as of alkali pretreatments and bleaching of refined pulps, on the chemical composition of the samples was analyzed. Morphological, structural, thermal, optical and viscometric properties were investigated as a function of the number of passages of refined/bleached suspensions through a defibrillator. For the unbleached suspensions, the effects of refining and bleaching on the properties of nanofibrils were evaluated, fixing the number of passages through the defibrillator. Microscopic studies demonstrated that nanoscale cellulose fibers were obtained from both pulps, with a higher yield for the refined/bleached and refined/unbleached pulp, at the expense of the unbleached/unrefined pulps. The study showed that, in addition to the effectiveness of the pre-treatments, there was an increase in the production efficiency of nanofibrils, as well as in the transparency of the bleached suspensions, while viscosity, thermal stability and crystallinity had reduced levels as the number of passages through the defibrillator increased, showing a gradual improvement in the transition from the micro- to the nano-scale. The present study contributed to the different methods that are available for the production of bamboo cellulose nanofibrils, which can be used in the production of biodegradable composites for various applications.

  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. 纸浆漂白臭氧处理段纤维素分子上羰基的形成%Formation of carbonyl groups on cellulose during ozone treatment of pulp:Consequences for pulp bleaching

    Institute of Scientific and Technical Information of China (English)

    余光华(译); 张丹(译); 龙柱(译)

    2015-01-01

    研究了纸浆臭氧漂白过程中,木素和乙烯糖醛酸的存在对纤维素上羰基的形成及纤维素降解的影响。在碱抽提段(E),采用CCOA方法{以咔唑-9-羧酸[2-(2-氨基氧杂乙氧基)-乙氧基]酰胺作为羰基的选择性荧光标记物}对纸浆中的羰基进行跟踪检测。研究表明:在臭氧漂白过程中,己烯糖醛酸、木素与臭氧反应形成的自由基导致纤维素和半纤维素上形成羰基并致使纤维素降解。此外,还发现羰基的总量在E段有所下降,但在随后P段,当H2O2不够稳定的时候又会有所增加。最后,提出了几种有助于减少羰基形成的方法。%The formation of carbonyl groups during the ozone treatment (Z) of eucalyptus (EucalyptusgrandisandEucalyptus urophylla hybrid) kraft pulps and their behaviors during subsequent alkaline stages were investigated by the CCOA method with carbazole-9-carboxylic acid [2-(2-aminooxethoxy)-ethoxy] amide (CCOA) as the carbonyl-selective fluorescence label. Several pulp samples with or without lignin and hexenuronic acid (HexA) were used to elucidate the effects of these components when present in unbleached kraft pulp. Both HexA and lignin increased the formation of carbonyl groups on cellulose and hemicellulose during ozonation. It was concluded that radicals are likely formed when ozone reacts with either lignin or HexA. These carbonyl groups were involved in cellulose depolymerization during subsequent alkaline extraction stages with sodium hydroxide (E) and alkaline hydrogen peroxide (P, in ZEP or ZP). Their numbers decreased after E but increased during P when H2O2 was not stabilized enough. Several ways to minimize the occurrence of carbonyl group formation are suggested.

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

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    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.

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

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    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.

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

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    Guanglei Zhao

    2010-06-01

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

  3. 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.

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

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    Kátia Maria Morais Eiras

    2009-01-01

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

  5. Formation of Carbonyl and Carboxyl Groups on Cellulosic Pulps: Effect on Alkali Resistance

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    Jordan Perrin

    2014-10-01

    Full Text Available Ozone bleaching generates carbonyl groups on the cellulose polymer when applied to unbleached kraft pulps. This suggests that pulp fully bleached with a totally chlorine-free (TCF sequence may contain more oxidized groups than standard elemental chlorine-free (ECF bleached pulp. A fully bleached pulp was treated with sodium hypochlorite to form oxidized groups (mostly carbonyls on the pure carbohydrates, which were investigated during subsequent alkaline treatment. Carbonyl groups had a strong impact on color development during alkaline treatment. Among the carbonyls, the keto groups were the most active. This was confirmed by the behavior of carbohydrate model compounds that contained aldehyde, keto, and/or carboxyl groups when subjected to alkaline conditions. A subsequent hydrogen peroxide (P stage effectively decreased the carbonyl content, which reduced yellowing during alkaline treatment. However, the oxidized cellulose was severely depolymerized. The addition of magnesium sulfate (Mg into the P stage minimized depolymerization while maintaining some of the carbonyls in the carbohydrates. It is proposed that Mg cations can hinder alkaline β-elimination, possibly by forming a complex with the carbonyl groups.

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

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    Emrah Peşman

    2011-04-01

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

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

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    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.

  8. Inflammatory response of human dental pulp to at-home and in-office tooth bleaching

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    Maysa Magalhães Vaz

    Full Text Available ABSTRACT Tooth bleaching is a technique of choice to obtain a harmonious smile, but bleaching agents may damage the dental pulp. Objective: This study evaluated the inflammatory responses of human dental pulp after the use of two bleaching techniques. Material and Methods: Pulp samples were collected from human third molars extracted for orthodontic reasons and divided into three groups: control - no tooth bleaching (CG (n=7; at-home bleaching with 15% carbamide peroxide (AH (n = 10, and in-office bleaching with 38% hydrogen peroxide (IO (n=12. Pulps were removed and stained with hematoxylin-eosin for microscopic analysis of inflammation intensity, collagen degradation, and pulp tissue organization. Immunohistochemistry was used to detect mast cells (tryptase+, blood vessels (CD31+, and macrophages (CD68+. Chi-square, Kruskal-Wallis, and Mann Whitney tests were used for statistical analysis. The level of significance was set at p0.05. No mast cells were found in the pulp samples analyzed. Conclusion: In-office bleaching with 38% hydrogen peroxide resulted in more intense inflammation, higher macrophages migration, and greater pulp damage then at-home bleaching with 15% carbamide peroxide, however, these bleaching techniques did not induce migration of mast cells and increased the number of blood vessels.

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

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    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  11. ENZYMATIC BLEACHING OF WHEAT STRAW SODA-AQ PULP BY LMS TREATMENT

    Institute of Scientific and Technical Information of China (English)

    Xiwen Wang; Huaiyu Zhan; Lili Xu

    2004-01-01

    Laccase has been proven that it has a good selectivity and efficiency in pulp bleaching. In this paper, the effects of LMS (Laccase Mediator System) treatment on delignification and bleaching of wheat straw pulp at various conditions, such as laccase dosage,temperature, oxygen pressure and pH, were investigated. The TCF sequence including LMS can bleach the wheat straw pulp to 81% ISO brightness with good strength. The synergetic biobleaching of LMS and xylanase of wheat straw pulp was also investigated. It was found that the final brightness and strength of synergetic biobleaching pulps increased to a certain extent and the bleaching selectivity was improved. The combination of the enzymes is feasible for the delignification and bleaching.

  12. ENZYMATIC BLEACHING OF WHEAT STRAW SODA--AQ PULP BY LMS TREATMENT

    Institute of Scientific and Technical Information of China (English)

    XiwenWang; HuaiyuZhan; LiliXu

    2004-01-01

    Laccase has been proven that it has a good selectivity and efficiency in pulp bleaching. In this paper, the effects of LMS (Laccase Mediator System) treatment on delignification and bleaching of wheat straw pulp at various conditions, such as laccase dosage, temperature, oxygen pressure and pH, were investigated. The TCF sequence including LMS can bleach the wheat straw pulp to 81% ISO brightness with good strength. The synergetic biobleaching of LMS and xylanase of wheat straw pulp was also investigated. It was found that the final brightness and strength of synergetic biobleaching pulps increased to a certain extent and the bleaching selectivity was improved. The combination of the enzymes is feasible for the delignification and bleaching.

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

    Science.gov (United States)

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

    2005-06-01

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

  18. 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.

  19. 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.

  20. Mercerization and Enzymatic Pretreatment of Cellulose in Dissolving Pulps

    OpenAIRE

    2013-01-01

    This thesis deals with the preparation of chemically and/or enzymatically modified cellulose. This modification can be either irreversible or reversible. Irreversible modification is used to prepare cellulose derivatives as end products, whereas reversible modification is used to enhance solubility in the preparation of regenerated cellulose. The irreversible modification studied here was the preparation of carboxymethyl cellulose (CMC) using extended mercerization of a spruce dissolving pulp...

  1. 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.

  2. 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.

  3. Microcrystalline Cellulose from Plant Wastes through Sodium Hydroxide-Anthraquinone-Ethanol Pulping

    Directory of Open Access Journals (Sweden)

    Olugbenga Oludayo Oluwasina

    2014-08-01

    Full Text Available Microcrystalline cellulose was prepared from wastes of Tithonia diversifolia, inflorescence stems of Musa sapientum, and Musa paradisiaca by soda-anthraquinone–ethanol pulping method. They were bleached by sodium chlorite and then alpha-cellulose was isolated, followed by preparation of microcrystalline cellulose. The study revealed the effect of various processing stages on the properties of the cellulose obtained. Yields of more than 80% of microcrystalline cellulose were obtained. Fourier transform infrared (FTIR and solid state 13C Nuclear magnetic resonance (13C NMR confirmed the presence of the major expected peaks in microcrystalline cellulose. Scanning electron microscopy (SEM revealed that Musa species had short fiber length and mixtures of non-aggregated spherical, rod-shaped and thread like microcrystalline cellulose, but Tithonia diversifolia had aggregate crystal packed formation. The results compared well with those of other authors and were able to meet most of the requirements specified in British Pharmacopoeia. The study revealed that a drug excipient like microcrystalline cellulose that could protect thermo-labile active ingredients could be successfully obtained from abundant non-woody agricultural wastes.

  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. Bleaching of soda pulp of fibres of Musa textilis nee (abaca) with peracetic acid.

    Science.gov (United States)

    Jiménez, L; Ramos, E; De la Torre, M J; Pérez, I; Ferrer, J L

    2008-03-01

    In this work, we studied the influence of operational variables in the bleaching of soda pulp of Musa textilis nee (abaca) [viz. temperature (55-85 degrees C), bleaching time (30-150 min) and peracetic acid concentration oven dry pulp (0.5-4.5%)] on the kappa number and viscosity of the bleached pulp, as well as on the breaking length, burst index and brightness of paper sheets made from it. For this purpose, we used a central composite factorial design in order to identify the optimum operating conditions. In this way equations relating the dependent variables to the operational variables of the bleaching process were derived. These equations reproduce the dependent variables with errors less than 12% for all, except the viscosity which was predicted with errors less than 18%. Obtaining bleached pulp with the highest possible viscosity (1519 ml/g), and paper sheets with the maximum possible breaking length (6547 m) and burst index (5.00 kN/g), entails using a temperature of 55 degrees C, a peracetic acid concentration of 4.5% and a bleaching time of 150 min. This provides a brightness of 79.90%, which is only 6.53% lower than the maximum possible value (85.48%).

  7. MODELING HYDROGEN PEROXIDE BLEACHING OF SODA PULP FROM OIL-PALM EMPTY FRUIT BUNCHES

    Directory of Open Access Journals (Sweden)

    Ana Ferrer

    2011-04-01

    Full Text Available The influence of the variables soda (0.5-3.0%, hydrogen peroxide (1.0-6.0% and time (1-5 h in the bleaching of soda pulp of empty fruit bunches (EFB from oil-palm, on the properties of bleached pulps, was studied. Polynomial and neural fuzzy models reproduced the results of brightness, kappa number, and viscosity of the pulps with errors less than 10%. By the simulation of the bleaching of pulp, using the polynomial and neural fuzzy models, it was possible to find optimal values of operating variables, so that the properties of bleached pulps differed only slightly from their best values and yet it was possible to save chemical reagents, energy, and plant size, operating with lower values of operating variables. Thus, operating with 1.13% soda concentration and 2.25% hydrogen peroxide concentration for 3 hours, a pulp with a brightness of 75.1% (8.1% below the maximum and a viscosity of 740 mL/g (10.4% less than the maximum value, was obtained.

  8. The effect of chemical composition on microfibrillar cellulose films from wood pulps: mechanical processing and physical properties.

    Science.gov (United States)

    Spence, Kelley L; Venditti, Richard A; Habibi, Youssef; Rojas, Orlando J; Pawlak, Joel J

    2010-08-01

    Films of microfibrillated celluloses (MFCs) from pulps of different yields, containing varying amounts of extractives, lignin, and hemicelluloses, were produced by combining refining and high-pressure homogenization techniques. MFC films were produced using a casting-evaporation technique and the physical and mechanical properties (including density, roughness, fold endurance and tensile properties) were determined. Homogenization of bleached and unbleached Kraft pulps gave rise to highly individualized MFCs, but not for thermo-mechanical pulp (TMP). The resulting MFC films had a roughness equivalent to the surface upon which the films were cast. Interestingly, after homogenization, the presence of lignin significantly increased film toughness, tensile index, and elastic modulus. The hornification of fibers through a drying and rewetting cycle prior to refining and homogenization did not produce any significant effect compared to films from never-dried fibers, indicating that MFC films can potentially be made from low-cost recycled cellulosic materials.

  9. 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.

  10. 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.

  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. 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

  13. Metabolites of chlorinated syringaldehydes in fish bile as biomarkers of exposure to bleached eucalypt pulp effluents.

    Science.gov (United States)

    Brumley, C M; Haritos, V S; Ahokas, J T; Holdway, D A

    1996-04-01

    Metabolites of chlorinated phenolic compounds in fish bile have been found to be sensitive biomarkers of bleached pulp mill effluent exposure. Chlorinated syringaldehydes are largely unstudied chlorophenolics found in bleached hardwood effluent. Sand flathead (Platycephalus bassensis), Australian marine fish, were exposed to 100% chlorine dioxide-bleached eucalypt pulp effluent at concentrations of 0.5, 2, and 8% (v/v) for 4 days. Metabolites of 2-chlorosyringaldehyde (2-CSA), the predominant chlorophenolic in this effluent, were measured in the bile. The major metabolite was the conjugate of 2-chloro-4-hydroxy-3,5-dimethoxy-benzylalcohol (2-CB-OH), the reduced product of 2-CSA. 2-CB-OH was found in all fish exposed to diluted effluent and was concentrated in the bile over 1000 times above 2-CSA levels in the effluent. A separate experiment examined the metabolic fate of 2,6-dichlorosyringaldehyde (2,6-DCSA), which is one of the major chlorophenolics in chlorine-bleached eucalypt pulp effluent. Sand flathead were exposed to 2,6-DCSA by intraperitoneal injection at 15 mg/kg or through the water to 0.5, 2, or 8 micrograms/liter for 4 days. Analysis of the bile revealed the major metabolite of 2,6-DCSA to be the conjugate of 2,6-dichloro-4-hydroxy-3,5-dimethoxybenzylalcohol, which was found in all exposed fish and was concentrated in the bile over 20,000 times above 2,6-DCSA exposure levels. Results reveal that the analysis of metabolites of chlorinated syringaldehydes in fish bile can provide a biomarker of bleached hardwood effluent exposure that is sensitive to low levels of exposure, specific to certain bleaching sequences, and correlates well with exposure concentrations.

  14. Light ECF bleaching for kraft pulp of eucalyptus and acacia%桉木和相思木硫酸盐浆在轻ECF漂白中性能的研究

    Institute of Scientific and Technical Information of China (English)

    逄锦江; 刘忠; 蒋华朋; 惠兰峰

    2013-01-01

      对桉木和相思木硫酸盐浆在轻ECF漂序中对比实验,其中对漂白前后纸张的物理性能、纤维长度、结晶度及纸浆基本性能进行检测。实验得出:在相同的漂白工艺下,相思木硫酸盐浆的选择性较好;相同漂白流程下,相思木硫酸盐浆可漂性高;在相同的盘磨转数下,桉木浆经过盘磨之后抗张强度和耐破强度都优于相思木浆;相思木和桉木浆经过漂白之后,纤维素的结晶度不同程度的降低,相思木硫酸盐浆无论原浆还是经过漂白的纸浆结晶度都高于桉木硫酸盐浆。%Comparison experiments of eucalyptus and acacia kraft pulp was carried out in light ECT bleaching sequence, in which the physical properties of paper, fiber length, degree of crystallinity and pulp basic performance were tested before and after bleaching. The results show that the acacia kraft pulp has the better selectivity, the bleachability of the aca-cia kraft pulp is higher than eucalyptus under the same bleaching process;the tensile strength and bursting strength of eucalyptus pulp are better than acacia wood pulp at the same revolution of refiner; the crystallinity degree of cellulose of both acacia and eucalyptus are reduced to some extent after bleaching, but the crystallinity of acacia kraft pulp, whether unbleached or bleached, is higher than eucalyptus kraft pulp.

  15. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-11-01

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

  17. 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.

  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. 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

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

    Science.gov (United States)

    Haruyama, Akiko; Kameyama, Atsushi; 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.

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

    Directory of Open Access Journals (Sweden)

    Akiko Haruyama

    2016-01-01

    Full Text Available 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Enzymatic Method for Rapid Determination of Oxalic Acid in Bleaching Filtrates from the Pulp and Paper Industry

    Institute of Scientific and Technical Information of China (English)

    HONG Feng; SJ(O)DE Anders; NILVEBRANT Nils-Olof; J(O)NSSON Leif J.

    2005-01-01

    Bleaching with oxygen-containing agents and recirculation of process streams in the pulp and paper industry has increased the accumulation of oxalic acid and danger for precipitation of calcium oxalate encrusts, scaling. Analysis and control of oxalic acid in bleaching filtrates is therefore becoming increasingly important in the pulp and paper industry.Chromatographic methods, such as IC and HPLC, are generally more time-consuming but are valuable as standard methods for determination of oxalic acid. However, the instrumentation needed is expensive and stationary. In this study, an enzymatic method based on oxalate oxidase and peroxidase was developed to determine oxalic acid in authentic bleaching filtrates using a spectrophotometer. The results showed that bleaching filtrates contain some compounds interfering with the enzymatic method.Pretreatment of the samples with activated charcoal was a successful approach for decreasing problems with interference. By using dilution followed by charcoal treatment, the results obtained from five bleaching filtrates with the colorimetric method correlated very well with those obtained using IC. This study offers a selective, fast and mobile analysis method to determine oxalic acid in bleaching filtrates from the pulp and paper industry. The convenient enzyme-based method improves the possibilities for control of critical oxalic acid concentrations in closed-loop bleaching streams.

  7. 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.

  8. 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

  9. 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.

  10. Hybrid Polyvinyl Alcohol and Cellulose Fiber Pulp Instead of Asbestos Fibers in Cement-Based Composites

    Science.gov (United States)

    Shokrieh, M. M.; Mahmoudi, A.; Shadkam, H. R.

    2015-05-01

    The Taguchi method was used to determine the optimum content of a four-parameters cellulose fiber pulp, polyvinyl alcohol (PVA) fibers, a silica fume, and bentonite for cement-based composite sheets. Then cement composite sheets from the hybrid of PVA and the cellulose fiber pulp were manufactured, and their moduli of rapture were determined experimentally. The result obtained showed that cement composites with a hybrid of PVA and cellulose fiber pulp had a higher flexural strength than cellulose-fiber- reinforced cement ones, but this strength was rather similar to that of asbestos-fiber-reinforced cement composites. Also, using the results of flexural tests and an analytical method, the tensile and compressive moduli of the hybrid of PVA and cement sheet were calculated. The hybrid of PVA and cellulose fiber pulp is proposed as an appropriate alternative for substituting asbestos in the Hatschek process.

  11. Effect of steam explosion and enzymatic pre-treatments on pulping and bleaching of Hesperaloe funifera.

    Science.gov (United States)

    Martín-Sampedro, R; Eugenio, M E; Villar, J C

    2012-05-01

    A non-wood raw material with high potential for pulp and paper applications (Hesperaloe funifera) was subjected to a steam explosion pre-treatment, and the subsequent effect of this pretreatment on biopulping and biobleaching was studied. An increase in the delignification rate, bigger than that reported for autohydrolysis and acid hydrolysis pre-treatments, and a reduction in chemical consumption were found during kraft pulping of the exploded samples. However, biopulping with the laccase-mediator system (LMS) did not lead to a reduction in the kappa number in either non-exploded or exploded unbleached pulps. On the other hand, the steam explosion pretreatment boosted the advantages of the LMS pre-treatment (decrease in kappa number and increase in brightness) favored biobleaching, with a 53.1% delignification rate and a final brightness of 67% ISO. Finally, the steam explosion pre-treatment also improved the color properties of the bleached pulp and reduced the hydrogen peroxide consumption by 24.6%.

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

    Directory of Open Access Journals (Sweden)

    Shuangxi Nie

    2014-07-01

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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Preparation and Characterization of Cellulose Nanofibers from Two Commercial Hardwood and Softwood Pulps

    DEFF Research Database (Denmark)

    Stelte, Wolfgang; Sanadi, Anand R.

    2009-01-01

    The aim of this work was to study the mechanical fibrillation process for the preparation of cellulose nanofibers from two commercial hard- and softwood cellulose pulps. The process consisted of initial refining and subsequent high-pressure homogenization. The progress in fibrillation was studied...... using different microscopy techniques, mechanical testing, and fiber density measurements of cellulose films prepared after different processing stages. The mechanical properties of cellulose films showed an increase in strength and stiffness with decreasing fiber size, and this stabilized after...... a certain number of passes in the homogenizer. Atomic force microscopy studies showed that the obtained cellulose nanofibers had diameters in the 10−25-nm range. The significant difference between the two samples was that the ultimate failure strain for cellulose films made of softwood fibers increased...

  19. BAMBOO CELLULOSIC PULP PRODUCED BY THE ETHANOL/WATER PROCESS FOR REINFORCEMENT APPLICATIONS

    Directory of Open Access Journals (Sweden)

    Viviane da Costa Correia

    2015-01-01

    Full Text Available Organosolv pulping is the clean chemical process of using organic solvents to aid in the removal of lignin and hemicellulose from lignocellulosic raw materials. This method provides facility for solvent recovery at the end of the process. In this work, it was to produce bamboo cellulosic pulp by the organosolv process evaluating different temperatures and reaction times, and the pulps were analyzed aiming their future application in the reinforcement of composites. The production of bamboo pulp by the organosolv process was studied varying the cooking conditions at 1, 2 and 3 h and 150, 170 and 190oC of temperature, in order to achieve the ideal conditions of yield, chemical and morphological characteristics of the pulp for its potential application in the reinforcement of composites. The best results for delignification (kappa number of 38, with relatively lower fiber degradation (viscosity of 625 cm3 g-1, aspect ratio of 40.4 and the index zero-span of 204 Nm g-1, were achieved for the pulping process at 190oC for 2 h. These pulping conditions can be considered as the more appropriate in the range of time intervals evaluated in this work. The higher mechanical strength and the lower incidence of morphological defects in the fiber (6.0% of curls and 10.6% of kinks can demonstrate the potential of organosolv bamboo pulp as a reinforcing element.

  20. Removal of the organic content from a bleached kraft pulp mill effluent by a treatment with silica-alginate-fungi biocomposites.

    Science.gov (United States)

    Duarte, Katia; Justino, Celine I L; Pereira, Ruth; Panteleitchouk, Teresa S L; Freitas, Ana C; Rocha-Santos, Teresa A P; Duarte, Armando C

    2013-01-01

    This study attempts a treatment strategy of a bleached kraft pulp mill effluent with Rhizopus oryzae or Pleurotus sajor caju encapsulated on silica-alginate (biocomposite of silica-alginate-fungi, with the purpose of reducing its potential impact in the environment. Active (alive) or inactive (death by sterilization) Rhizopus oryzae or Pleurotus sajor caju was encapsulated in alginate beads. Five beads containing active and inactive fungus were placed in a mold and filled with silica hydrogel (biocomposites). The biocomposites were added to batch reactors containing the bleached kraft pulp mill effluent. The treatment of bleached kraft pulp mill effluent by active and inactive biocomposites was performed throughout 29 days at 28°C. The efficiency of treatment was evaluated by measuring the removal of organic compounds, chemical oxygen demand and the relative absorbance ratio over time. Both fungi species showed potential for removal of organic compounds, colour and chemical oxygen demand. Maximum values of reduction in terms of colour (56%), chemical oxygen demand (65%) and organic compounds (72-79%) were attained after 29 days of treatment of bleached kraft pulp mill effluent by active Rhizopus oryzae biocomposites. The immobilization of fungi, the need for low fungal biomass, and the possibility of reutlization of the biocomposites clearly demonstrate the industrial and environmental interest in bleached kraft pulp mill effluent treatment by silica-alginate-fungi biocomposites.

  1. 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.

  2. Synthesis and Characterization of Cellulose Acetate from TCF Oil Palm Empty Fruit Bunch Pulp

    Directory of Open Access Journals (Sweden)

    Fauzi Muhammad Djuned

    2014-06-01

    Full Text Available Cellulose acetate (CA was successfully synthesized by the acetylation of TCF cellulose pulp from oil palm empty fruit bunches (OPEFB at room temperature, using acetic anhydride as the acetylating agent and acetic acid as the solvent in the presence of sulfuric acid/sodium bisulfate as catalysts. Degree of substitution (DS was controlled by the variables of acetylation time and acetic anhydride to cellulose ratio, under the heterogeneous state. The product (CA obtained was characterized through Fourier transform infrared spectroscopy (FTIR, nuclear magnetic resonance spectroscopy (NMR, differential scanning calorimetry (DSC, X-ray diffraction (XRD, and scanning electron microscopy (SEM. The results indicate that the CA obtained has characteristics similar to commercial CA, and DS is significantly dependent on acetylation time and the acetic anhydride-to-cellulose ratio.

  3. 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.

  4. Development and trends in chlorine dioxide bleaching with integrated chlorate electrolysis for the cellulose industry

    Energy Technology Data Exchange (ETDEWEB)

    Wintzer, P.

    1980-05-01

    Rising demand for cellulose and paper and the environmental measures necessary in this branch of industry compel the companies involved to invest large sums. In particular, waste water from bleaching operations causes difficulties in biological waste water purification owing to high chlorolignin content. The sequence of chlorination steps have been optimized for each quality of wood, and the increasing use of chlorine dioxide leads to an expansion of chlorate electrolysis and chlorine dioxide plant at the expense of chlorine. The consumption of chemicals for the various cellulose qualities is considered. During the past 30 years, the Muenchner process for production of ClO/sub 2/ has proved environmentally sound and is being continuously improved. Only hydrochloric acid and water are needed as raw materials. The chlorine formed in this process is converted into hydrochloric acid, hypochlorite, and chlorine water. All steps of the processes require only liquids and gases permitting a favourable, closed mode of operation without by-products or waste salts. New chlorate cells built since 1969 are equipped exclusively with coated titanium anodes (load between 6 and 100 kA) with DC efficiencies of 92 to 95%. Annual world production of sodium chlorate exceeds 1 million tonnes. The rate of increase has long remained steady at 5%.

  5. Human dental pulp stem cell behavior using natural nanotolith/bacterial cellulose scaffolds for regenerative medicine.

    Science.gov (United States)

    Olyveira, Gabriel Molina; Acasigua, Gerson Arisoly Xavier; Costa, Ligia Maria Manzine; Scher, Cristiane Regina; Xavier Filho, Lauro; Pranke, Patricia Helena Lucas; Basmaji, Pierre

    2013-08-01

    Adhesion and Viability study with human dental pulp stem cell using natural nanotolith/bacterial cellulose scaffolds for regenerative medicine are presented at first time in this work. Nanotolith, are osteoinductors, i.e., they stimulate bone regeneration, enabling higher cells migration for bone tissue regeneration formation. This is mainly because nanotoliths are rich minerals present in the internal ear of bony fish. In addition, are part of a system which acts as a depth sensor and balance, acting as a sound vibrations detector and considered essential for the bone mineralization process, as in hydroxiapatites. Nanotoliths influence in bacterial cellulose was analyzed using transmission infrared spectroscopy (FTIR). Results shows that fermentation process and nanotoliths agglomeration decrease initial human dental pulp stem cell adhesion however tested bionanocomposite behavior has cell viability increase over time.

  6. Spherical nanocrystalline cellulose (NCC) from oil palm empty fruit bunch pulp via ultrasound assisted hydrolysis.

    Science.gov (United States)

    Zianor Azrina, Z A; Beg, M Dalour H; Rosli, M Y; Ramli, Ridzuan; Junadi, Norhafzan; Alam, A K M Moshiul

    2017-04-15

    Nanocrystalline cellulose (NCC) was isolated from oil palm empty fruit bunch pulp (EFBP) using ultrasound assisted acid hydrolysis. The obtained NCC was analysed using FESEM, XRD, FTIR, and TGA, and compared with raw empty fruit bunch fibre (REFB), empty fruit bunch pulp (EFBP), and treated empty fruit bunch pulp (TEFBP). Based on FESEM analysis, it was found that NCC has a spherical shaped after acid hydrolysis with the assistance of ultrasound. This situation was different compared to previous studies that obtained rod-like shaped of NCC. Furthermore, the crystallinity of NCC is higher compared to REFB and EFBP. According to thermal stability, the NCC obtained shows remarkable sign of high thermal stability compared to REFB and EFBP.

  7. The rheological properties of bamboo cellulose pulp/ionic liquid system

    Science.gov (United States)

    Zhang, Y. F.; Zhang, P. R.; Wu, J.; Jia, Q. X.; Liu, X. Y.

    2016-07-01

    In this study, two kinds of spinning solutions were prepared by dissolving bamboo cellulose pulp into 1-ethyl-3-methyl imidazole chloride salt ([EMIM] Cl) and 1-butyl-3-methyl imidazole diethyl phosphate salt ([BMIM]DEP) ionic liquids, respectively. Furthermore, the rotational rheometer was used to test the steady-state rheological properties of above as-prepared spinning solutions. The research results show that both of these two ionic liquids exhibit better solubility to the bamboo cellulose pulp. The apparent viscosities(ηa) decrease with the increased temperature(T) and shear rate(γ) and increase with the increased concentration. The non-Newtonian index(n) declined with the increase of both shear rate and concentration, as well as increased with the build-up temperature. The structural viscosity index(Δη) increased with the increased concentration and tended to decrease with temperature rise. Meanwhile, viscous flow activation energy(Eη) decreases with the increased share rate as well as the concentration. According to the results, it can be seen that the bamboo cellulose pulp/[EMIM]Cl with the concentration of 6% at 70°C exhibits better spinnability.

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

    OpenAIRE

    2006-01-01

    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 optimiz...

  9. 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.

  10. 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)

  11. IMPROVEMENT OF TCF BLEACHING OF OLIVE TREE PRUNING RESIDUE PULP BY ADDITION OF A LACCASE AND/OR XYLANASE PRE-TREATMENT

    Directory of Open Access Journals (Sweden)

    Raquel Martín-Sampedro,

    2012-02-01

    Full Text Available This study aimed at assessing the biobleachability of soda pulps obtained from olive tree pruning residue. The enzymatic (LMS pre-treatment was applied prior to a simple totally chlorine free (TCF bleaching sequence, consisting of an alkaline extraction and a hydrogen peroxide stage. Additionally, the effect of adding xylanase jointly with or prior to LMS was evaluated. All of these enzymatic pre-treatments were associated with an enhancement of the bleaching sequence. The best results were found when both enzymes were applied in the same stage: lowest hydrogen peroxide consumption (63 percent; kappa number, 11.6; brightness, 46 percent ISO. The mechanical properties observed were similar to those reported by other authors who have studied pulps from olive tree pruning residue. Finally, bleached pulps were subjected to accelerated ageing in order to assess the evolution of brightness and colorimetric properties. Although biobleached pulps showed lower stability upon ageing, the best optical properties, even after ageing, were observed in pulps treated with both xylanase and laccase.

  12. 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.

  13. Combination of alkaline and enzymatic treatments as a process for upgrading sisal paper-grade pulp to dissolving-grade pulp.

    Science.gov (United States)

    Ibarra, David; Köpcke, Viviana; Larsson, Per Tomas; Jääskeläinen, Anna-Stiina; Ek, Monica

    2010-10-01

    A sequence of treatments consisting of an initial xylanase treatment followed by cold alkaline extraction and a final endoglucanase treatment was investigated as a process for upgrading non-wood paper-grade pulps to dissolving-grade pulps for viscose production. Five commercial dried bleached non-wood soda/AQ paper pulps, from flax, hemp, sisal, abaca, and jute, were studied for this purpose. Commercial dried bleached eucalyptus dissolving pulp was used as reference sample. Sisal pulp showed the highest improvement in Fock's reactivity, reaching levels nearly as high or even higher than that of eucalyptus dissolving pulp (65%), and a low hemicellulose content (3-4%) when was subjected to this sequence of treatments. The viscosity, however, decreased considerably. A uniform and narrow molecular weight distribution was observed by size exclusion chromatography. (13)C nuclear magnetic resonance spectroscopy and Raman microspectroscopy revealed that the cellulose structure consisted of cellulose I.

  14. 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

  15. COMPARISON OF PLATE AND CONICAL FILLINGS IN REFINING OF BLEACHED SOFTWOOD AND HARDWOOD PULPS

    Institute of Scientific and Technical Information of China (English)

    K.Koskenhely; K.Nieminen; E.Hiltunen; H.Paulapuro

    2004-01-01

    The purpose of this study was to compare plate and conical refiner fillings in refining of softwood and hardwood pulp fibers. Contrary to expectations,better tensile strength values were achieved when BSW was refined with conical fillings and the development of strength Was found to be insensitive to variations in refining intensity. A bar microprocile was measured with the aid of a profilometer. The leading edges of conicalfilling bars.were found to be rounder. A possible reason for the better tensile strength of pulp refined with conical fillings is that the round edge helps large SW fiber flocs to enter the space between the bars, resulting in less heterogeneous or more efficient treatment of fibers.The recorded gap closure values supported the above interpretation. The gap between conical fillings was found to become wider when pulp consistency and thus fiber flocculation increased, whereas increased pulp consistency decreased the gap between plate fillings, which was further reflected as increased fiber cutting. The reduction in fiber length was proportional to the increase in gap closure,supporting the earlier theory that fibers are squeezed and crushed between the bars. More attention should be paid to the wear of filling materials when refining BSW. A filling material which wears so that the bar edges are rounded would seem to promote high tensile strength and high average fiber length.

  16. COMPARISON OF PLATE AND CONICAL FILLINGS IN REFINING OF BLEACHED SOFTWOOD AND HARDWOOD PULPS

    Institute of Scientific and Technical Information of China (English)

    K.Koskenhely; K.Nieminen; E.Hiltunent; H.Paulapuro

    2004-01-01

    The purpose of this study was to compare plate and conical refiner fillings in refining of softwood and hardwood pulp fibers. Contrary to expectations, better tensile strength values were achieved when BSW was refined with conical fillings and the development of strength was found to be insensitive to variations in refining intensity. A bar microprofile was measured with the aid of a profilometer. The leading edges of conical filling bars were found to be rounder. A possible reason for the better tensile strength of pulp refined with conical fillings is that the round edge helps large SW fiber flocs to enter the space between the bars, resulting in less heterogeneous or more efficient treatment of fibers. The recorded gap closure values supported the above interpretation. The gap between conical fillings was found to become wider when pulp consistency and thus fiber flocculation increased, whereas increased pulp consistency decreased the gap between plate fillings, which was further reflected as increased fiber cutting. The reduction in fiber length was proportional to the increase in gap closure, supporting the earlier theory that fibers are squeezed and crushed between the bars. More attention should be paid to the wear of filling materials when refining BSW. A filling material which wears so that the bar edges are rounded would seem to promote high tensile strength and high average fiber length.

  17. 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。

  18. 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.

  19. Isolation and characterization of resin acid degrading bacteria found in effluent from a bleached kraft pulp mill.

    Science.gov (United States)

    Morgan, C A; Wyndham, R C

    1996-05-01

    Thirteen resin acid degrading bacteria enriched on abietic or dehydroabietic acids were isolated from waste water from the aerated stabilization basin of a bleached kraft pulp mill. Standard biochemical tests were used to characterize each isolate. Each isolate was tested for its ability to degrade six abietane- and pimarane-type resin acids. Resin acid concentrations were determined by high pressure liquid chromatography and UV absorbance. Cluster analysis based on phenotypic characteristics identified two distinct clusters of degraders that differed in their ability to utilize carbohydrates as carbon sources. Fatty acid methyl ester analysis of representative isolates from each cluster identified A19-6a and D11-13 as Comamonas and Alcaligenes species, respectively. To determine genotypic relatedness, enterobacterial repetitive intergenic consensus sequences were used to amplify genomic DNA fragments from 10 isolates. These results supported the phenotypic analysis for all isolates tested except A19-5 and A19-6b. These two organisms were clustered closely together based on phenotype but had distinctly different banding patterns, suggesting that they are not related genotypically. All isolates degraded a subset of the six resin acid congeners. Isolates A19-3, A19-6a, A19-6b, and D11-37 were the most effective at degrading all six congeners.

  20. Characterization of the crystalline structure of cellulose using static and dynamic FT-IR spectroscopy.

    Science.gov (United States)

    Akerholm, Margaretha; Hinterstoisser, Barbara; Salmén, Lennart

    2004-02-25

    The cellulose structure is a factor of major importance for the strength properties of wood pulp fibers. The ability to characterize small differences in the crystalline structures of cellulose from fibers of different origins is thus highly important. In this work, dynamic FT-IR spectroscopy has been further explored as a method sensitive to cellulose structure variations. Using a model system of two different celluloses, the relation between spectral information and the relative cellulose Ialpha content was investigated. This relation was then used to determine the relative cellulose Ialpha content in different pulps. The estimated cellulose I allomorph compositions were found to be reasonable for both unbleached and bleached chemical pulps. In addition, it was found that the dynamic FT-IR spectroscopy technique had the potential to indicate possible correlation field splitting peaks of cellulose Ibeta.

  1. 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.

  2. 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...

  3. 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.

  4. Treatment of pulp and paper industry bleaching effluent by electrocoagulant process

    Energy Technology Data Exchange (ETDEWEB)

    Sridhar, R., E-mail: sridhar36k@yahoo.co.in [Department of Chemical Engineering, Kongu Engineering College, Perundurai, Erode 638052, TN (India); Sivakumar, V., E-mail: drvsivakumar@yahoo.com [Department of Food Technology, Kongu Engineering College, Perundurai, Erode 638052, TN (India); Prince Immanuel, V., E-mail: princeimmanuel79@yahoo.com [Department of Chemical Engineering, Erode Sengunthar Engineering College, Thudupathi, Erode 638057, TN (India); Prakash Maran, J., E-mail: prakashmaran@gmail.com [Department of Food Technology, Kongu Engineering College, Perundurai, Erode 638052, TN (India)

    2011-02-28

    The experiments were carried out in an electrocoagulation reactor with aluminum as sacrificial electrodes. The influence of electrolysis time, current density, pH, NaCl concentration, rotational speed of the stirrer and electrode distance on reduction of color, COD and BOD were studied in detail. From the experimental results, 15 mA/cm{sup 2} current density, pH of 7, 1 g/l NaCl, 100 rpm, 28 deg, C temperature and 3 cm electrode distance were found to be optimum for maximum reduction of color, COD and BOD. The reduction of color, COD and BOD under the optimum condition were found to be 94%, 90% and 87% respectively. The electrode energy consumption was calculated and found to be varied from 10.1 to 12.9 kWh/m{sup 3} depending on the operating conditions. Under optimal operating condition such as 15 mA/cm{sup 2} current density, pH of 7, 1 g/l NaCl, 100 rpm, 28 deg, C temperature and 3 cm electrode distance, the operating cost was found to be 1.56 US $/m{sup 3}. The experimental results proved that the electrocoagulation is a suitable method for treating bleaching plant effluents for reuse.

  5. BIO-CONVENTIONAL BLEACHING OF KRAFT-AQ PULP OF A. CADAMBA BY CRUDE XYLANASES FROM COPRINELLUS DISSEMINATUS MLK-03 AND EFFECT OF RESIDUAL ENZYME ON EFFLUENT LOAD

    Directory of Open Access Journals (Sweden)

    Mohan Lal

    2011-04-01

    Full Text Available A new thermo-alkali-tolerant crude xylanase from Coprinellus disseminatus decreased kappa number by 34.38% and improved brightness and viscosity by 1.6 and 6.47% respectively after XE1-stage during prebleaching of Anthocephalus cadamba kraft-AQ pulp. At 2.4% chlorine demand, crude xylanase in a XECEHH (X= enzymatic prebleaching stage, E= extraction stage, C= chlorination stage, H= hypochlorite stage bleaching sequence improved pulp brightness, tensile index, burst index, and double fold numbers by 3.66%, 4.78%, 6.38%, and 11.11%, respectively with a reduction in viscosity (10.59% and tear index (10.77% compared to the control. Combined bleach effluent of the XECEHH sequence mitigated adsorable organic halides (AOX by 21% and increased chemical oxygen demand (COD, bio-chemical oxygen demand (BOD, and colour by 67.18%, 84.78%, and 97.53%, respectively, compared to the control. Residual enzymes that entered during enzymatic prebleaching stage decreased AOX, COD, BOD, and colour of combined effluent of the XECEHH bleaching sequence progressively and on 6th day, and these were reduced by 23.78%, 0.04%, 15.00%, and 0.61%, respectively, compared to the control.

  6. 利用机械浆生产木质纳米纤维素%Development of nano-ligno-cellulose produced from mechanical pulp

    Institute of Scientific and Technical Information of China (English)

    陈翠

    2014-01-01

    The objective in this work was to develop a methodology for producing mechanical pulp based nano-ligno-cellulose (NLC) from ifnes fractions. Also there has been a great deal of enthusiasm to evaluate particle size distribution of NLC. In this work the Crill characterisation technique was used. The Crill values of TMP and CTMP based nano-ligno-celluloses were measured as a function of the homogenisation time. Results showed that the Crill value of both TMP-NLC and CTMP-NLC correlated with the homogenisation time. Another objective was to utilize NLC as strength additives in paper and board grades. Laboratory sheets of CTMP and bleached kraft pulp (BKP), with the addition of their respective NLC, were made in a Rapid Köthen sheet former. It was found that handsheets of pulp ifbers blended with NLC improved the z-strength and other important mechanical properties for similar sheet densities.%开发了一种可以利用机械浆细小纤维组分生产纳米纤维素的方法,并对木质纳米纤维素粒径分布进行表征。本次研究使用了Cril表征技术,测定TMP纳米纤维素和CTMP纳米纤维素Crill值,作均质化时间的函数。结果显示,TMP-NLC和CTMP-NLC的Crill值都与均质化时间相关。本研究的另一目的是使用木质纳米纤维素作为纸和纸板的增强剂,加入到CTMP和BKP浆料内,结果显示,在手抄片紧度相似的情况下,加入木质纳米纤维素后纸页的Z向强度和其它一些重要的机械性能指标都有所改善。

  7. 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)

  8. The effect of non-silicon stabilizer on properties of bleached bagasse pulp%过氧化氢漂白稳定剂对漂后蔗渣浆性能的影响

    Institute of Scientific and Technical Information of China (English)

    刘艳兰; 林本平; 陈克复

    2013-01-01

    The effect of non-silicon stabilizer on bagasse bleached pulp with pressured hydrogen peroxide bleaching was studied. The results indicate that in use of 0.1%PP-1 and 0.5%PP-2 in pressured hydrogen peroxide bleaching of a chelated oxygen-delignification bagasse pulp, the brightness of bleached pulp is achieved to 85.0%ISO. The fiber morphology, physical strength properties and the charge characteristics of bleached pulp from (PP-1+PP-2) process are compared to those of bleached pulp from Na2SiO3 process. The ifber length, ifber width, ifber coarseness, and length distribution of bleached pulp from (PP-1+PP-2) process is similar to those of bleached pulp from Na2SiO3 process, but the ifnes content and curl index of ifber are lower than those of bleached pulp from Na2SiO3 process. The tensile index, surface charge and carboxyl group content of bleached pulp from (PP-1+PP-2) process are higher than those of bleached pulp from Na2SiO3 process, but the Zeta potential is lower than that of bleached pulp from Na2SiO3 process.%研究了非硅过氧化氢漂白稳定剂(P P-1+P P-2)对蔗渣压力过氧化氢漂白浆强度性能和纤维形态的影响。研究结果表明:添加0.1%PP-1+0.5%PP-2的稳定剂后,蔗渣压力过氧化氢漂白浆的白度达到85.0%I S O。与使用硅酸钠的漂后浆相比,非硅稳定剂(P P-1+P P-2)漂后浆的抗张指数提高了2.6N. m/g,撕裂指数和耐破指数基本相当。(P P-1+P P-2)作为稳定剂的蔗渣漂后浆的纤维长度、宽度和粗度与N a2S i O3漂后浆的相当,但纤维卷曲指数和细小纤维的含量低于N a2S i O3漂后的蔗渣浆。(P-1+P P-2)漂后的蔗渣浆与N a2S i O3的漂后浆相比,纸浆的表面电荷和羧基含量较高,而Z电位较低。

  9. 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.

  10. 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.

  11. Branqueamento de polpa celulósica kraft de eucalipto com peróxido ácido ativado por molibdênio Kraft pulp bleaching with molybdenum activated acid peroxide (P Mo stage

    Directory of Open Access Journals (Sweden)

    Marcos Sousa Rabelo

    2009-01-01

    Full Text Available Optimum conditions to run the P Mo stage for bleaching eucalyptus kraft pulp were 90 ºC, pH 3.5, 2 h, 0.1 kg/t Mo and 5 kg/t H2O2. The P Mo stage efficiency increased with decreasing pH (1.5-5.5 and increasing temperature (75-90 ºC, time (2-4 h, and hydrogen peroxide (3-10 kg/t and molybdenum concentration (0.1-0.4 kg/t. The implementation of the P Mo stage, as replacement for the A stage, decreased total active chlorine demand of the OAZDP sequence by 6 kg/t to reach 90% ISO, both in laboratory and mill scale. Such practice resulted in decreased bleaching chemical costs to produce fully bleached pulp of 90% ISO.

  12. Bio-conventional bleaching of kadam kraft-AQ pulp by thermo-alkali-tolerant xylanases from two strains of Coprinellus disseminatus for extenuating adsorbable organic halides and improving strength with optical properties and energy conservation.

    Science.gov (United States)

    Lal, Mohan; Dutt, Dharm; Tyagi, C H

    2012-04-01

    Two novel thermo-alkali-tolerant crude xylanases namely MLK-01 (enzyme-A) and MLK-07 (enzyme-B) from Coprinellus disseminatus mitigated kappa numbers of Anthocephalus cadamba kraft-AQ pulps by 32.5 and 34.38%, improved brightness by 1.5 and 1.6% and viscosity by 5.75 and 6.47% after (A)XE(1) and (B)XE(1)-stages, respectively. The release of reducing sugars and chromophores was the highest during prebleaching of A. cadamba kraft-AQ pulp at enzyme doses of 5 and 10 IU/g, reaction times 90 and 120 min, reaction temperatures 75 and 65°C and consistency 10% for MLK-01 and MLK-07, respectively. MLK-07 was more efficient than MLK01 in terms of producing pulp brightness, improving mechanical strength properties and reducing pollution load. MLK-01 and MLK-07 reduced AOX by 19.51 and 42.77%, respectively at 4% chlorine demands with an increase in COD and colour due to removal of lignin carbohydrates complexes. A. cadamba kraft-AQ pulps treated with xylanases from MLK-01 to MLK-07 and followed by CEHH bleaching at half chlorine demand (2%) showed a drastic reduction in brightness with slight improvement in mechanical strength properties compared to pulp bleached at 4% chlorine demand. MLK-01 reduced AOX, COD and colour by 43.83, 39.03 and 27.71% and MLK-07 by 38.34, 40.48 and 30.77%, respectively at half chlorine demand compared to full chlorine demand (4%). pH variation during prebleaching of A. cadamba kraft-AQ pulps with strains MLK-01 and MLK-07 followed by CEHH bleaching sequences showed a decrease in pulp brightness, AOX, COD and colour with an increase in mechanical strength properties, pulp viscosity and PFI revolutions to get a beating level of 35 ± 1 °SR at full chlorine demand.

  13. 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.

  14. 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.

  15. 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

    2013-04-02

    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.

  16. Removal of Organic Pollutants and Decolorization of Bleaching Effluents from Pulp and Paper Mill by Adsorption using Chemically Treated Oil Palm Empty Fruit Bunch Fibers

    Directory of Open Access Journals (Sweden)

    Mohd Shaiful Sajab

    2014-06-01

    Full Text Available Treatment of bleaching effluents from pulp and paper mills using oil palm empty fruit bunch (EFB fibers as an adsorbent was conducted to remove color and organic pollutants. Empty fruit bunch fibers were chemically modified with polyethylenimine to enhance the adsorption capacity toward anionic species in the effluents. Effluents from the primary clarifier and aerated treatment pond were treated, and the performance of the adsorbent was investigated in terms of decolorization, total organic carbon, and oxygen demand level. Increasing adsorbent dosage and lower pH resulted in greater adsorption performance. The highest decolorization and reduction of total organic carbon of the effluents were 95.0% and 58.2%, respectively. The adsorption equilibrium can be achieved after 4 h of the adsorption process.

  17. Improvement in thermostability of metagenomic GH11 endoxylanase (Mxyl) by site-directed mutagenesis and its applicability in paper pulp bleaching process.

    Science.gov (United States)

    Satyanarayana, Digvijay Verma T

    2013-12-01

    An attempt has been made for enhancing the thermostability of xylanase (Mxyl) retrieved from a compost-soil-based metagenomic library. The analysis of the structure of xylanase by molecular dynamics simulation revealed more structural fluctuations in β-sheets. When the surface of β-sheets was enriched with arginine residues by substituting serine/threonine by site-directed mutagenesis, the enzyme with four arginine substitutions (MxylM4) exhibited enhanced thermostability at 80 °C. The T 1/2 of MxylM4 at 80 °C, in the presence of birchwood xylan, increased from 130 to 150 min at 80 °C without any alteration in optimum pH and temperature and molecular mass. Improvement in thermostability of MxylM4 was corroborated by increase in T m by 6 °C over that of Mxyl. The K m of MxylM4, however, increased from 8.01 ± 0.56 of Mxyl to 12.5 ± 0.32 mg ml(-1), suggesting a decrease in the affinity as well as specific enzyme activity. The Mxyl as well as MxylM4 liberated chromophores and lignin-derived compounds from kraft pulp, indicating their applicability in pulp bleaching.

  18. 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.

  19. 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

  20. 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

  1. Improve Acidic H2O2bleaching with Molybdate for Eucalyptus Kraft Pulp%钼酸盐对桉木 KP 浆 H2O2 漂白的改善效果

    Institute of Scientific and Technical Information of China (English)

    赵建; 石淑兰; 胡惠仁; 范兴刚

    2001-01-01

    研究了钼酸盐对桉木硫酸盐氧漂浆酸性 H2O2 漂白的改善效果,探讨了各种影响因素(钼酸盐用量、漂液 pH 值、H2O2 用量、氧强化的碱抽提和洗涤方式)对酸性 H2O2 漂白结果的影响。结果表明:添加少量的钼酸盐能有效地促进酸性 H2O2 的脱木素反应,提高脱木素效率,增加纸浆的白度。当钼酸盐用量为 01% 时,脱木素程度比单纯的 H2O2 漂段提高 278%,白度增加 43%(ISO),而粘度的损失不大。%In this paper,effect of various conditions(molybdate charge,PH,peroxide charge,reinforced-alkali-extraction with oxygen,and washing method) on bleaching results in the activated acidic hydrogen peroxide bleaching with molybdate for eucalyptus kraft pulp is investigated. The results indicated that adding molybdate to the acidic hydrogen peroxide bleaching stage improved delignification degree and increased ISO brightness of bleached pulp(for example,with 0.1% molybdate charge,delignification degree and pulp brightness could be increased 27.8% and 4.3 points respectively)but had little effect on the pulp viscosity.

  2. 纸浆漂白废水中可吸附有机氯化物的特性研究进展%Progress in researches on the characteristics of adsorbable organic chloride from paper pulp bleaching wastewater

    Institute of Scientific and Technical Information of China (English)

    唐国民; 赵光磊; 王双

    2012-01-01

    纸浆漂白废水中含有的可吸附有机氯化物是国内外造纸工业严控的废物,是造纸环保界关注的重点.在查阅资料基础上,对目前关于纸浆漂白废水中可吸附有机氯化物的成分、分布、生成以及降解特性等方面的研究进行了述评,重点介绍了纸浆漂白废水中可吸附有机氯化物的生成及降解性能方面的研究成果,并在此基础上对今后的研究趋势进行了展望.%The adsorbable organic chloride contained in paper pulp bleaching wastewater is a kind of strictly controlled waste and the emphases concerned in paper-making field. Based on datum searching, the components, distribution, formation, degradation characteristics,etc. of the adsorbable organic chloride from paper and pulp bleaching wastewater at present are reviewed. The research achievements in the formation and degradation capacity of the adsorbable organic chloride from paper pulp bleaching wastewater are introduced emphatically. Based on the study stated above .future research trends are looked forward.

  3. Post-treatment of anaerobic effluent by ozone and ozone/UV of a kraft cellulose pulp mill.

    Science.gov (United States)

    Chaparro, T R; Pires, E C

    2015-01-01

    Pulp and paper mill effluents represent a challenge when treatment technologies are considered, not only to reduce organic matter, but also to reduce the toxicological effects. Although anaerobic treatment has shown promising results, as well as advantages when compared with an aerobic system, this process alone is not sufficient to reduce recalcitrant compounds. Thus, an advanced oxidation process was applied. This experiment was performed to determine the effect of ozone and ozone/UV treating a horizontal anaerobic immobilized biomass reactor effluent from a kraft cellulose pulp mill for 306 days with an organic volumetric load of 2.33 kgCOD/m³/day. The removal of organic compounds was measured by the following parameters: adsorbable organically bound halogens (AOX), total phenols, chemical oxygen demand (COD), dissolved organic carbon and absorbance values in the UV-visible spectral region. Moreover, ecotoxicity and genotoxicity tests were conducted before and after treatment with ozone and ozone/UV. At an applied ozone dosage of 0.76 mgO₃/mgCOD and an applied UV dosage of 3.427 Wh/m(3), the organochlorine compounds measured as AOX reached removal efficiencies of 40%. Although the combination of ozone/UV showed better results in colour (79%) and total phenols (32%) compared with only ozone, the chronic toxicity and the genotoxicity that had already been removed in the anaerobic process were slightly increased.

  4. A novel approach for the preparation of nanocrystalline cellulose by using phosphotungstic acid.

    Science.gov (United States)

    Liu, Yefei; Wang, Haisong; Yu, Guang; Yu, Qingxue; Li, Bin; Mu, Xindong

    2014-09-22

    In this work, a sustainable and green process to prepare nanocrystalline cellulose (NCC) from bleached hardwood pulp was demonstrated. Rod-like nanocrystalline cellulose with the size of 15-40 nm in width and hundreds of nanometers in length was obtained through H3PW12O40 (HPW)-catalyzed hydrolysis of bleached pulp fibers under the mild reaction conditions. Thermogravimetric analysis revealed that the resulting NCC exhibited much higher thermal stability than the partially sulfated NCC (prepared by sulfuric acid). In addition, the concentrated HPW could be easily recovered and recycled through the extraction with diethyl ether, and the recovered HPW could be reused for several rounds of cellulose hydrolysis without activity lost. These fundamental studies are of crucial importance for the development and application of NCC products/NCC-based biomaterials with good thermal stability.

  5. 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

  6. Biotreatment on cellulose fluff pulp: quaternary ammonium salts finish and grafting with beta-cyclodextrin.

    Science.gov (United States)

    Ghemati, Djamila; Oudia, Atika; Aliouche, Djamel; Lamouri, Saad

    2009-11-01

    For its potential performances to be expanded, cellulose needs to be processed in different ways. Therefore, an object of the present work was to provide a chemical modification of cellulose through: a specific finish with two quaternary ammonium salts (namely Aliquat 336 and Aliquat 1529, respectively). Chemical grafting of beta-cyclodextrin derivative (beta-CD) onto fibers followed by the inclusion of benzoic acid in the grafted CD cavities as a probe chemical. Physicochemical properties and performances of the untreated and treated fibers have been determined with infrared spectra, microscopy, swelling measurements, antimicrobial finishing tests, and dye adsorption. Our results show that cellulose fibers can be efficiently modified with no significant changes in its structural and surface properties; the treated fibers show an attractive behavior in swelling, dye adsorption and antibacterial activity.

  7. PEROXIDE BLEACHING OF LOW-FREENESS TMP

    Institute of Scientific and Technical Information of China (English)

    ZhongLiu; Y.Ni; Z.Li,G.Court

    2004-01-01

    Peroxide bleaching is an essential unit operation toproduce value-added mechanical pulp-based papergrade. In this paper, we presented the results fromperoxide bleaching of low-freeness TMP for theproduction of SC paper. Two aspects wereaddressed; the effect of pulp strength and theformation of anionic trashes. The strength properties,such as tensile, burst and zero-span tensile, areimproved after the peroxide bleaching process. Theamount of anionic trashes formed is almostproportional to the hydrogen peroxide charge.

  8. Increasing efficiency of enzymatic hemicellulose removal from bamboo for production of high-grade dissolving pulp.

    Science.gov (United States)

    Zhao, Lingfeng; Yuan, Zhaoyang; Kapu, Nuwan Sella; Chang, Xue Feng; Beatson, Rodger; Trajano, Heather L; Martinez, D Mark

    2017-01-01

    To improve the efficiency of enzymatic hemicellulose removal from bamboo pre-hydrolysis kraft pulp, mechanical refining was conducted prior to enzyme treatment. Refining significantly improved the subsequent hemicellulose removal efficiency by xylanase treatment. Results showed that when PFI refining was followed by 3h xylanase treatment, the xylan content of the bamboo pre-hydrolysis kraft pulp (after first stage oxygen delignification) could be decreased to 2.72% (w/w). After bleaching of enzyme treated pulp, the alpha-cellulose content was 93.4% (w/w) while the xylan content was only 2.38%. The effect of refining on fibre properties was investigated in terms of freeness, water retention value, fibre length and fibrillation characteristics. The brightness, reactivity and viscosity were also determined to characterize the quality of final pulp. Results demonstrated the feasibility of combining refining and xylanase treatment to produce high quality bamboo dissolving pulp.

  9. 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.

  10. 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.

  11. 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.

  12. 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)

  13. 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.

  14. 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%.

  15. 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.

  16. 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.

  17. 浆粕性质对纤维素/[Bmim]Cl纺丝原液性能的影响%Effect of pulp characteristics on properties of cellulose/[ Bmim ] Cl spinning dope

    Institute of Scientific and Technical Information of China (English)

    张慧慧; 蔡涛; 周振兴; 邵惠丽; 胡学超

    2011-01-01

    Using three kinds of cotton and wood cellulose pulps as raw material and the ionic liquid of 1-butyl-3-methylimidazo-lium chloride ( [ Bmim]Cl) as solvent, the effect of the degree of polymerization (DP) and a -cellulose content of pulps on the cellulose dissolution in [Bmim]Cl, the rheological behavior of the spinning dope and the properties of the resulted fibers were discussed. The results showed that the higher the DP and α- cellulose content of cellulose pulp, the longer the dissolution time of cellulose in [ Bmim] Cl. The DP of pulp was the dominating factor on the dissolution rate of cellulose in [ Bmim] Cl as compared with α- cellulose content. Three kinds of cellulose/[ Bmim]Cl spinning dopes belonged to the typical shear thinning fluids. High DP and high α- cellulose content of the pulp contributed high structural viscosity index and viscous flow activation energy to the spinning dope. The pulp with high DP and high a- cellulose content helped to prepare the fiber with high mechanical properties.%选用棉浆和木浆3种纤维素浆粕为原料,以离子液体1-丁基-3-甲基咪唑氯盐([Bmim] Cl)为溶剂,探讨了浆粕的聚合度(DP)和α-纤维素含量对其在[Bmim] Cl中的溶解情况、纺丝液的流变行为及其纤维性能的影响.结果表明:浆粕的DP和α-纤维素含量越高,其在[Bmim] Cl中完全溶解所需时间就越长;相对于α-纤维素含量而言,DP对浆粕溶解速率的影响为主要因素;3种纤维素/[Bmim]Cl纺丝液都属于切力变稀流体,由高DP和高α-纤维素含量的浆粕所制得的纺丝液的结构粘度指数大且粘流活化能高;高DP和高α-纤维素含量的浆粕有利于获得力学性能更好的纤维素纤维.

  18. 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.

  19. NEWSPRINT FROM SODA BAGASSE PULP IN ADMIXTURE WITH HARDWOOD CMP PULP

    OpenAIRE

    Seed Rahman Jafari Petroudy; Hossein Resalati Mail; pejman Rezayati Charani Mail

    2011-01-01

    Based on global research and experiences producing newsprint from bagasse, the possibility of using bagasse chemical pulp in the furnish of local mill-made mixed hardwood CMP pulp was studied at laboratory scale, for making newsprint. Bagasse soda chemical pulp at digester yield of about 47% was bleached to about 60% brightness by single stage hydrogen peroxide. The effects of using up to 30% bagasse chemical pulp in a blend with hardwood CMP pulp, with or without softwood kraft pulp, were st...

  20. 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.

  1. 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.

  2. APPLICATION OF SURFACTANTS AS PULPING ADDITIVES IN SODA PULPING OF BAGASSE

    Directory of Open Access Journals (Sweden)

    Yahya Hamzeh

    2009-11-01

    Full Text Available The effects of several non-ionic commercial surfactants and their dosage on soda pulping and ECF bleaching of soda and soda-surfactant pulps of bagasse were investigated. The properties of bleachable pulps obtained with conventional soda and with soda-surfactants were studied and compared. The results showed application of surfactants during the soda pulping of bagasse decreased kappa number and improved the yield and brightness of resulting pulp. Using the surfactants reduced alkali consumption during pulping. The bleaching experiments showed that the pulps obtained with the three types of applied surfactants namely, ELA-2, FAE-20, and PEG1000 could be easily bleached with D0ED1 or D0EpD1 sequences. The addition of most used surfactants in soda pulping of bagasse led to higher brightness in comparison to reference pulp with the same bleaching sequence. Strength properties of bleached pulps obtained with surfactants were higher than the pulp obtained with conventional soda pulping.

  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. NEWSPRINT FROM SODA BAGASSE PULP IN ADMIXTURE WITH HARDWOOD CMP PULP

    Directory of Open Access Journals (Sweden)

    Seed Rahman Jafari Petroudy

    2011-05-01

    Full Text Available Based on global research and experiences producing newsprint from bagasse, the possibility of using bagasse chemical pulp in the furnish of local mill-made mixed hardwood CMP pulp was studied at laboratory scale, for making newsprint. Bagasse soda chemical pulp at digester yield of about 47% was bleached to about 60% brightness by single stage hydrogen peroxide. The effects of using up to 30% bagasse chemical pulp in a blend with hardwood CMP pulp, with or without softwood kraft pulp, were studied. The results showed that superior hand sheet properties could be achieved by using bagasse chemical pulp; in comparison with main mill pulp furnish (83% hardwood CMP pulp and 17% imported long fiber pulp. In other words, by using bagasse chemical pulp in a blend with local mill made hardwood CMP pulp, acceptable newsprint could be made with considerable reduction in the consumptions of hardwood species and softwood reinforcing kraft pulp.

  5. APPLICATION OF SURFACTANTS AS PULPING ADDITIVES IN SODA PULPING OF BAGASSE

    OpenAIRE

    2009-01-01

    The effects of several non-ionic commercial surfactants and their dosage on soda pulping and ECF bleaching of soda and soda-surfactant pulps of bagasse were investigated. The properties of bleachable pulps obtained with conventional soda and with soda-surfactants were studied and compared. The results showed application of surfactants during the soda pulping of bagasse decreased kappa number and improved the yield and brightness of resulting pulp. Using the surfactants reduced alkali consumpt...

  6. Valorization of residual Empty Palm Fruit Bunch Fibers (EPFBF) by microfluidization: production of nanofibrillated cellulose and EPFBF nanopaper.

    Science.gov (United States)

    Ferrer, Ana; Filpponen, Ilari; Rodríguez, Alejandro; Laine, Janne; Rojas, Orlando J

    2012-12-01

    Different cellulose pulps were produced from sulfur-free chemical treatments of Empty Palm Fruit Bunch Fibers (EPFBF), a by-product from palm oil processing. The pulps were microfluidized for deconstruction into nanofibrillated cellulose (NFC) and nanopaper was manufactured by using an overpressure device. The morphological and structural features of the obtained NFCs were characterized via atomic force and scanning electron microscopies. The physical properties as well as the interactions with water of sheets from three different pulps were compared with those of nanopaper obtained from the corresponding NFC. Distinctive chemical and morphological characteristics and ensuing nanopaper properties were generated by the EPFBF fibers. The NFC grades obtained compared favorably with associated materials typically produced from bleached wood fibers. Lower water absorption, higher tensile strengths (107-137 MPa) and elastic modulus (12-18 GPa) were measured, which opens the possibility for valorization of such widely available bioresource.

  7. Delignification of Pinus radiata kraft pulp by treatment with a yeast genetically modified to produce laccases; Deslignificacion de pasta kraft de Pinus radiata con una levadura geneticamente modificada para producir lacasa

    Energy Technology Data Exchange (ETDEWEB)

    Arana-Cuenca, A.; Tellez-Jurado, A.; Yague, S.; Ferminan, E.; Carbajo, J. M.; Dominguez, A.; Gonzalez, T.; Villar, J. C.; Gonzalez, A. E.

    2010-07-01

    Cellulose pulp bleaching is one of the main biotechnological applications of fungal laccases due to their capacity to degrade lignin from unbleached pulp. This application requires low cost enzyme production and higher enzyme concentrations than those obtained from the natural fungal producers. Heterologous expression of laccase in yeasts is an option for producing these enzymes on an industrial scale. In this work, we have demonstrated the heterologous expression of the cglcc1 gene, responsible for laccase production in the basidiomicetous fungus Coriolopsis gallica, in the yeast Kluyveromyces lactis. In order to know if the transformed yeast has delignificant capability, a Pinus radiata kraft pulp has been incubated with it. After the treatment, a significant decrease in kappa number (13%) and in lignin content (22%) was observed. These results showed the delignificant capability of this transformed yeast. It can be concluded that the use of genetically modified microorganisms that do not demonstrate cellulolitic activity can produce high laccase levels and delignify cellulose pulps with a potential applications in cellulose pulp bleaching. (Author) 25 refs.

  8. Optimization the soda-AQ process for cellulose pulp production and energy content of black liquor from L. leucocephala K360.

    Science.gov (United States)

    Feria, M J; García, J C; Díaz, M J; Garrote, G; López, F

    2012-09-01

    A commercial variety of Leucaena leucocephala K360 was used for pulp production and papermaking employing the soda-anthraquinone process. Also, the chemical and energy contents of the resultant black liquors were determined to simultaneously optimize: pulp and paper production and energy generation. A process temperature of (185°C), an operating time of (120 min) and an active alkali concentration of (21%) provided sheets of paper with good strength (tensile index of 12.12 Nm/g, burst index of 0.38 kPa m(2)/g, tear index of 1.29 mN m(2)/g and a Kappa number of 20.5) and black liquor with a greater calorific value (14.1 MJ/kg) than that obtained with higher active alkali concentrations. However, reducing the active alkali concentration to a level in the low operation range led to less marked degradation of cellulose and allowed paper sheets with good properties to be obtained and energy to be optimally produced from the black liquor.

  9. 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

  10. An improved X-ray diffraction method for cellulose crystallinity measurement.

    Science.gov (United States)

    Ju, Xiaohui; Bowden, Mark; Brown, Elvie E; Zhang, Xiao

    2015-06-05

    We show in this work a modified X-ray diffraction method to determine cellulose crystallinity index (CrI). Nanocrystalline cellulose (NCC) derived from bleached wood pulp was used as a model substrate. Rietveld refinement was applied with consideration of March-Dollase preferred orientation at the (001) plane. In contrast to most previous methods, three distinct amorphous peaks identified from new model samples which used to calculate CrI. A 2 theta range from 10° to 75° was found to be more suitable to determine CrI and crystallite structural parameters such as d-spacing and crystallite size. This method enables a more reliable measurement of CrI of cellulose and may be applicable to other types of cellulose polymorphs.

  11. 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

  12. FRACTURE RESISTANCE AND FAILURE PATTERN OF TEETH SUBMITTED TO INTERNAL BLEACHING WITH 37% CARBAMIDE PEROXIDE, WITH APPLICATION OF DIFFERENT RESTORATIVE PROCEDURES

    OpenAIRE

    Gerson Bonfante; Osvaldo Bazzan Kaizer; Luiz Fernando Pegoraro; Accácio Lins do Valle

    2006-01-01

    OBJECTIVE: This study investigated the compressive fracture strength and failure pattern in premolars submitted to endodontic treatment and internal bleaching with 37% carbamide peroxide for 21 days, with application of different restorative procedures. MATERIAL AND METHODS: Six groups were employed (n = 10): 1) non-bleached teeth and pulp chamber sealed with IRM; 2) bleached teeth and pulp chamber sealed with IRM; 3) bleached teeth and pulp chamber filled with light cured composite resin; 4)...

  13. Properties of cellulose micro/nanofibers obtained from eucalyptus pulp fiber treated with anaerobic digestate and high shear mixing

    Science.gov (United States)

    High production costs remain the single greatest factor limiting wider use of cellulose micro/nanofibers in the industry. The objective of the present study was to investigate the potential of using a low-cost bacteria-rich digestate (liquid anaerobic digestate – AD supernatant) on milled eucalyptus...

  14. Changes in the microstructure and properties of aspen chemithermomechanical pulp fibres during recycling.

    Science.gov (United States)

    Fu, Yingjuan; Wang, Rongrong; Li, Dejuan; Wang, Zhaojiang; Zhang, Fengshan; Meng, Qinglin; Qin, Menghua

    2015-03-06

    The effects of recycling on the microstructure and properties of bleached aspen chemithermomechanical pulp (CTMP) fibres were systematically investigated. The low-temperature nitrogen adsorption and atomic force microscopy results showed that a substantial amount of large pores and most of the very small pores in the fibre wall closed and the fibre surface became less coarse and porous during recycling. The partial cocrystallisation of cellulose microfibrils took place, as reflected in the increment of the cellulose crystallinity and the width of the crystallite in the 0 0 2 lattice plane. These irreversible structural changes caused significant hornification of the recycled fibres, leading to the loss of swelling and bonding capability. The decrease of the tensile index, burst index, and tear index further demonstrated the deterioration of the fibre properties. However, the single-fibre strength considerably increased after recycling, which was mainly due to the enlarged cellulose aggregates in the fibre wall.

  15. 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.

  16. 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。

  17. 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.

  18. Comparative effect of mechanical beating and nanofibrillation of cellulose on paper properties made from bagasse and softwood pulps.

    Science.gov (United States)

    Afra, Elyas; Yousefi, Hossein; Hadilam, Mohamad Mahdi; Nishino, Takashi

    2013-09-12

    Cellulose fibers were fibrillated using mechanical beating (shearing refiner) and ultra-fine friction grinder, respectively. The fibrillated fibers were then used to make paper. Mechanical beating process created a partial skin fibrillation, while grinding turned fiber from micro to nanoscale through nanofibrillation mechanism. The partially fibrillated and nano fibrillated fibers had significant effects on paper density, tear strength, tensile strength and water drainage time. The effect of nanofibrillation on paper properties was quantitatively higher than that of mechanical beating. Paper sheets from nanofibrillated cellulose have a higher density, higher tensile strength and lower tear strength compared to those subjected to mechanical beating. Mechanical beating and nanofibrillation were both found to be promising fiber structural modifications. Long water drainage time was an important drawback of both fibrillation methods.

  19. 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).

  20. Pilot-plant pulping studies on four abaca varieties. I. Soda pulping

    Energy Technology Data Exchange (ETDEWEB)

    Zerrudo, J.V.; Visperas, R.V.; Ballon, C.H.

    1981-01-01

    Cooking of spindle-stripped and decorticated abaca varieties with 13.5% NaOH for 2.5 hours at 170 degrees gave pulp in average yield of 69.1% and 60.9%, respectively. All the pulps had low permanganate numbers, indicating that they can be bleached easily. The strength properties of abaca pulp were related to the plant variety, and Sabahon variety gave pulp with best strength characteristics.

  1. 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.

  2. 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

  3. Cellulose nanocrystals' production in near theoretical yields by 1-butyl-3-methylimidazolium hydrogen sulfate ([Bmim]HSO4)-mediated hydrolysis.

    Science.gov (United States)

    Mao, Jia; Heck, Barbara; Reiter, Günter; Laborie, Marie-Pierre

    2015-03-06

    We report on near theoretical yield production of cellulose I nanocrystals (CNCs) using a two-step hydrolysis with the mildly acidic ionic liquid (IL) 1-butyl-3-methylimidazolium hydrogen sulfate ([Bmim]HSO4) in aqueous solution from common cellulosic sources. Two successive Taguchi experimental plans were performed to evaluate the impact of selected reaction parameters (T, t, H2O:IL ratio) and their interactions on the CNCs' yield from bleached softwood kraft pulp (SWP), bleached hardwood kraft pulp (HWP) and microcrystalline cellulose (MCC). With these experimental plans, the molar yield for extraction of nanocrystals was optimized to near theoretical levels, reaching 57.7±3.0%, 57.0±2.0%, and 75.6±3.0%, for SWP, HWP and MCC, respectively. The reaction yields corresponded to a relative crystalline region recovery of 84.1±5.3%, 71.7±1.3%, 76.0±2.0% from SWP, HWP and MCC, respectively. The collected nanocrystals exhibited high aspect ratios (36-43), negligible sulfur content (0.02-0.21%) and high solvent dispersibility in comparison to those obtained with the traditional sulfuric acid method. Additionally these near theoretical yields were achieved for mild reaction conditions with the combined severity factor of 2 and 3 for MCC and pulp, respectively. Overall this two-stage IL-mediated preparation of nanocrystals combines the advantages of achieving high product quality, high reaction yields and mild conditions.

  4. 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.

  5. Combined effects of raw materials and solvent systems on the preparation and properties of regenerated cellulose fibers.

    Science.gov (United States)

    Chen, Jinghuan; Guan, Ying; Wang, Kun; Zhang, Xueming; Xu, Feng; Sun, Runcang

    2015-09-05

    To investigate the combined effects of materials and solvents on the preparation, structural and mechanical properties of regenerated cellulose fibers, four cellulosic materials (microcrystalline cellulose, cotton linter pulp, bamboo pulp and bleached softwood sulfite dissolving pulp) and six non-derivative solvents (NaOH/urea aqueous solution, N,N-dimethylacetamide/lithium chloride, N-methyl-morpholine-N-oxide, 1-butyl-3-methylimidazolium chloride, 1-allyl-3-methylimidazolium chloride and 1-ethyl-3-methylimidazolium acetate) were used to prepare fibers with wet spinning method. The results showed that the dissolvability of solvent was the determining factor in cellulose dissolution, and the dissolving time was influenced by the raw materials' properties, such as molecular weight, exposed area and hemicellulose content. The crystallinity and elongation at break of the fibers were almost fixed and not affected by the materials and solvents. However, the tensile strength of the fibers was directly proportional to the molecular weight of the raw materials, and varied with the type of solvents through cellulose degradation.

  6. ISOLATION OF PECTIC ACIDS FROM BLEACHED TMP WATER AND AGGREGATION OF MODEL AND TMP PECTIC ACIDS BY CALCIUM

    Directory of Open Access Journals (Sweden)

    Anna C. Sundberg

    2007-11-01

    Full Text Available Pectins are important structural elements in spruce fibres. Alkaline peroxide bleaching of spruce thermomechanical pulp (TMP causes degradation and demethylation of pectins, yielding high-charge-density pectic acids. The pectic acids in fibres contribute strongly to the negative fibre charge, and the dissolved pectic acids increase the cationic demand of bleached TMP water. In this study, a method to isolate pectic acids from peroxide-bleached TMP pulp water is presented. The pectic acids were isolated and purified in good yield using a polyacrylate resin to remove lignin, a cellulose filter to remove galactoglucomannans (GGM, and an anion exchange resin to separate pectic acids from neutral carbohydrates. Salts and residual low-molar-mass carbohydrates were further removed from the isolated pectic acids by dialysis. The isolated pectic acids (>80% purity had a low molar mass and a wide polydispersity (5.9 kDa, MW/MN 3.3. The aggregation and precipitation of the isolated pectic acids, as well as citrus fruit pectic acids with well-defined molar masses, by Ca2+-ions were studied. The molar mass of pectic acids was a key factor determining the precipitation of Ca2+-pectates. Pectic acids below 6 kDa were not precipitated by Ca2+, while higher molar masses led first to partial and then to complete precipitation. The precipitated Ca2+-pectates may impair paper machine runnability and paper quality.

  7. 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。

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. EFFECTS OF PROCESSINGOPERATIONS ON ZETAPOTENTIAL AND CATIONICDEMAND OF PULPS

    Institute of Scientific and Technical Information of China (English)

    NishiK.Bhardwajt; SanjayKumar; PramodK.Bajpai[

    2004-01-01

    The zeta potential and cationic demands of variouskraft pulps - unbleached, bleached and beaten to dif-ferent freeness levels were determined in the labora-tory. The zeta potential of pulp where the final stagewas a lignin degrading and dissolving treatment suchas alkaline extraction or hypochlorite was lower thanthe unbleached pulp. The cationic demand of un-bleached pulp was higher compared to that ofbleached pulp. Beaten pulps showed larger cationicdemands than the unbeaten pulps, which can be at-tributed to the larger specific surface area of pulpcomponents. Fibres become increasingly electroneg-ative when beaten and therefore cationic demand ofpulps increases with beating. When the zeta potentialmethod is used with furnishes of different freeness,the linear relationship is observed. However, theslope is decreasing with the decrease in freeness ofthe pulp.

  13. Pulping and paper properties of Palmyra palm fruit fibers

    OpenAIRE

    Waranyou Sridach

    2010-01-01

    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...

  14. 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.

  15. Skin Bleaching

    OpenAIRE

    Ahmed, Samira M.

    2015-01-01

    In this project, I aim to investigate the reasoning behind the practice of skin bleaching by analyzing the documentary ”Dark Girls”, to gain a better understanding of race and colorism issues. Also this project tries to see if there is a connection with history and if this has been a part of making the european beauty ideal determine the choices black’s make in regards to beauty.

  16. EFFECTS OF PROCESSING OPERATIONS ON ZETA POTENTIAL AND CATIONIC DEMAND OF PULPS

    Institute of Scientific and Technical Information of China (English)

    Nishi K. Bhardwaj; Sanjay Kumar; Pramod K. Bajpai

    2004-01-01

    Thc zeta potential and cationic demands of various kraft pulps - unbleached, bleached and beaten to different freeness levels were determined in the laboratory. The zeta potential of pulp where the final stage was a lignin degrading and dissolving treatment such as alkaline extraction or hypochlorite was lower than the unbleached pulp. The cationic demand of unbleached pulp was higher compared to that of bleached pulp. Beaten pulps showed larger cationic demands than the unbeaten pulps, which can be attributed to the larger specific surface area of pulp components. Fibres become increasingly electronegative when beaten and therefore cationic demand of pulps increases with beating. When the zeta potential method is used with furnishes of different freeness,the linear relationship is observed. However, the slope is decreasing with the decrease in freeness of the pulp.

  17. COMPARISON OF ECF-LIGHT,TCF AND CEH BLEACHING OF NON-NOOD FIBERS

    Institute of Scientific and Technical Information of China (English)

    Thomas Greschik; Jiri Basta,Christian Blom; Huaiyu Zhan; Bingyun Li; Chenrong Qin

    2004-01-01

    A comparative evaluation of DQP, OQP and CEH bleaching of non-wood fibres has revealed that wheat straw, reed, bagasse and bamboo pulps can be bleached to brightness levels of just above 80% ISO,when applying an OQP bleaching sequence and to brightness levels of about 85% ISO when applying the DQP sequence using 10 - 15 kg/tp of ClO2 (aC1.),15 - 20 kg/tp of H2O2 together with 1 - 2 kg/tp of EDTA. The P.C. numbers of the DQP and OQP bleached pulps are much lower and the viscosity much higher than those of the CEH bleached pulps.Compared with CEH pulps, both the DQP and OQP pulps had better strength properties, particularly Tear Index. In spite of their higher final brightness levels,the DQP pulps show similar or better strength properties than the OQP pulps. A comparison of the CEH and DQP effluents showed that the DQP bleaching could reduce the pollution load (CODCDBOD5, SS) by 35 to 60% without the need for recirculation of any effluent streams. The AOX levels could be reduced by 87 to 93%.

  18. 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.

  19. 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.

  20. The Effect of Enzymatic Treatments of Pulps on Fiber and Paper Properties

    OpenAIRE

    Žnidaršič-Plazl, P.; Rutar, V.; Ravnjak, D.

    2009-01-01

    Biotechnological treatment of pulps provides great potential for the reduction of energy consumption and greenhouse gas emissions. In the present work, the influence of different commercial cellulases and xylanases or their mixtures on the quality of different bleached kraft pulps was investigated. The effects of enzymes on reducing sugars release and changes in fiber length were assessed for 3 different eucalyptus pulps, for a pulp consisting of a mixture of hardwoods and for softwood pulp. ...

  1. 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

  2. Hazy Transparent Cellulose Nanopaper

    Science.gov (United States)

    Hsieh, Ming-Chun; Koga, Hirotaka; Suganuma, Katsuaki; Nogi, Masaya

    2017-01-01

    The aim of this study is to clarify light scattering mechanism of hazy transparent cellulose nanopaper. Clear optical transparent nanopaper consists of 3–15 nm wide cellulose nanofibers, which are obtained by the full nanofibrillation of pulp fibers. At the clear transparent nanopaper with 40 μm thickness, their total transmittance are 89.3–91.5% and haze values are 4.9–11.7%. When the pulp fibers are subjected to weak nanofibrillation, hazy transparent nanopapers are obtained. The hazy transparent nanopaper consists of cellulose nanofibers and some microsized cellulose fibers. At the hazy transparent nanopaper with 40 μm thickness, their total transmittance were constant at 88.6–92.1% but their haze value were 27.3–86.7%. Cellulose nanofibers are solid cylinders, whereas the pulp fibers are hollow cylinders. The hollow shape is retained in the microsized cellulose fibers, but they are compressed flat inside the nanopaper. This compressed cavity causes light scattering by the refractive index difference between air and cellulose. As a result, the nanopaper shows a hazy transparent appearance and exhibits a high thermal durability (295–305 °C), and low thermal expansion (8.5–10.6 ppm/K) because of their high density (1.29–1.55 g/cm3) and crystallinity (73–80%).

  3. A comparison of chlorinated organic material produced by chlorine and chlorine dioxide bleaching

    Energy Technology Data Exchange (ETDEWEB)

    McKaque, A.B.; Reeve, D.W. [Univ. of Toronto (Canada)

    1995-12-31

    Chlorine and chlorine dioxide react differently with pulp during bleaching and produce different types of organic by-products. The main differences are the large reduction in the amount of AOX (adsorbable organic halogen) in the effluent and EOX (extractable organic halogen) in the pulp. This talk reviews the differences in the amounts and types of chlorinated organic by-products produced by the two different bleaching agents.

  4. Application of Ionic Liquids in the Pulp and Paper and the Cellulose Industries%离子液体在制浆造纸及纤维素工业的应用

    Institute of Scientific and Technical Information of China (English)

    徐永建; 王皎

    2011-01-01

    A new type of environmentally friendly green solvents,namely ionic liquids (ILS) has many outstanding properties,making them promisingly employing in many fields.In this paper,the dissolution mechanisms of cellulose in ionic liquids were discussed.Firstly,it was necessary to clarify the relationships between cellulose soubility and ionic liquids structures,cellulose dissolution rate and dissolving conditions,and the dissolving effects on the cellulose.The methods to improve the dissolution rate based on the selection of ionic liquids and the determination of reaction conditions were recommended.The methods to improve the dissolution rate based on the selection of ionic liquids and the determination of reaction conditions were recommended.The,advantages of making fiber derivative materials,such as magnetic material,absorbent,biofilm using ionic liquids as solvent were expounded,and the application of ionic liquids in waste water treatment,deinking,pulping process of pulp and paper making field was prospected.Field was prospected.Finally,the industrialization obstacles and research direction of ionic liquids were provided.%从离子液体结构、溶解反应条件对纤维素溶解的影响以及纤维素溶解前后的差异等方面总结了离子液体对纤维素的溶解能力,阐述了可能的溶解机理。从选取离子液体,确定反应条件的角度提出了提高纤维素溶解率的方法。介绍了以离子液体为溶剂制备磁性材料、吸附剂、生物膜等纤维衍生材料及其应用于相关领域的优势,展望了离子液体在制浆造纸废水处理、脱墨、制浆领域中的应用前景。提出了离子液体工业化存在的问题及离子液体的研究方向。

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

    Directory of Open Access Journals (Sweden)

    Vasanta V. Thakur,

    2012-02-01

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

  6. Properties of extracted Eucalyptus globulus kraft pulps

    OpenAIRE

    Duarte, G. V.; Gamelas, J.A.F.; Ramarao, B. F.; Amidon, T. E.; Ferreira, P. J.

    2012-01-01

    This work was a comprehensive study of the properties of extracted Eucalyptus globulus kraft pulps. Five levels of hot water extraction were performed, each followed by kraft cooking to three different kappa numbers. As extraction took place, the hemicelluloses content of the kraft pulps was reduced from 21%-22% to 3%-4% and, conversely, the cellulose fraction increased from 73%-75% to 85%-90%. Fiber length decreased for all pulps and kink index increased greatly with extraction. The dispersi...

  7. 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.

  8. 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.

  9. 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.

  10. CAMPURAN PULP TANDAN KOSONG KELAPA SAWIT DAN SELULOSA MIKROBIAL NATA DE CASSAVA DALAM PEMBUATAN KERTAS

    Directory of Open Access Journals (Sweden)

    Khaswar Syamsu

    2014-04-01

    Full Text Available Nowadays, forest-extracted wood cellulose still predominantly serves as raw material for pulp and paper manufacture in Indonesia. Consequently, the deforestation rate has alarmingly increased. The purpose of this research is to study the use of mixed microbial cellulose pulp from nata de cassava and pulp from empty oil palm fruit bunch (EOPFB for paper manufacture. In this research, pulp of nata de cassava’s microbial cellulose was mixed with EOPFB pulp at various proportions. Additives (i.e. 2% alum, 2.5% tapioca starch, and 5% kaolin were added to such mixture. Sheet forming without additives was made as a control. Addition of microbial cellulose tends to increase the physical and strength properties of paper and decrease the capability to absorb water significantly. The mixture of pulp of empty oil palm fruit bunch and microbial cellulose from nata de cassava has a potency to substitute wood pulp for paper manufacture.

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. Absorbent properties of carboxymethylated fiber, hydroentangled nonwoven and regenerated cellulose: a comparative study

    Science.gov (United States)

    Commercially-available, bleached cotton fibers, rayon, and their hydroentangled counterparts were carboxymethylated to produce cellulosic products with increased absorbency. These cellulose materials were tested for absorbance, spectroscopic properties, degree of substitution and carding ability. Ca...

  17. 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.

  18. 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.

  19. Methods of pretreating comminuted cellulosic material with carbonate-containing solutions

    Science.gov (United States)

    Francis, Raymond

    2012-11-06

    Methods of pretreating comminuted cellulosic material with an acidic solution and then a carbonate-containing solution to produce a pretreated cellulosic material are provided. The pretreated material may then be further treated in a pulping process, for example, a soda-anthraquinone pulping process, to produce a cellulose pulp. The pretreatment solutions may be extracted from the pretreated cellulose material and selectively re-used, for example, with acid or alkali addition, for the pretreatment solutions. The resulting cellulose pulp is characterized by having reduced lignin content and increased yield compared to prior art treatment processes.

  20. Cellulose Isolation Methodology for NMR Analysis of Cellulose Ultrastructure

    Directory of Open Access Journals (Sweden)

    Art J. Ragauskas

    2011-11-01

    Full Text Available In order to obtain accurate information about the ultrastructure of cellulose from native biomass by 13C cross polarization magic angle spinning (CP/MAS NMR spectroscopy the cellulose component must be isolated due to overlapping resonances from both lignin and hemicellulose. Typically, cellulose isolation has been achieved via holocellulose pulping to remove lignin followed by an acid hydrolysis procedure to remove the hemicellulose components. Using 13C CP/MAS NMR and non-linear line-fitting of the cellulose C4 region, it was observed that the standard acid hydrolysis procedure caused an apparent increase in crystallinity of ~10% or less on the cellulose isolated from Populus holocellulose. We have examined the effect of the cellulose isolation method, particularly the acid treatment time for hemicellulose removal, on cellulose ultrastructural characteristics by studying these effects on cotton, microcrystalline cellulose (MCC and holocellulose pulped Populus. 13C CP/MAS NMR of MCC indicated that holocellulose pulping and acid hydrolysis has little effect on the crystalline ultrastructural components of cellulose. Although any chemical method to isolate cellulose from native biomass will invariably alter substrate characteristics, especially those related to regions accessible to solvents, we found those changes to be minimal and consistent in samples of typical crystallinity and lignin/hemicellulose content. Based on the rate of the hemicellulose removal, as determined by HPLC-carbohydrate analysis and magnitude of cellulose ultrastructural alteration, the most suitable cellulose isolation methodology utilizes a treatment of 2.5 M HCl at 100 °C for a standard residence time between 1.5 and 4 h. However, for the most accurate crystallinity results this residence time should be determined empirically for a particular sample.

  1. 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.

  2. Understanding Longitudinal Wood Fiber Ultra-structure for Producing Cellulose Nanofibrils Using Disk Milling with Diluted Acid Prehydrolysis

    Science.gov (United States)

    Qin, Yanlin; Qiu, Xueqing; Zhu, J. Y.

    2016-10-01

    Here we used dilute oxalic acid to pretreat a kraft bleached Eucalyptus pulp (BEP) fibers to facilitate mechanical fibrillation in producing cellulose nanofibrils using disk milling with substantial mechanical energy savings. We successfully applied a reaction kinetics based combined hydrolysis factor (CHFX) as a severity factor to quantitatively control xylan dissolution and BEP fibril deploymerization. More importantly, we were able to accurately predict the degree of polymerization (DP) of disk-milled fibrils using CHFX and milling time or milling energy consumption. Experimentally determined ratio of fibril DP and number mean fibril height (diameter d), DP/d, an aspect ratio measurer, were independent of the processing conditions. Therefore, we hypothesize that cellulose have a longitudinal hierarchical structure as in the lateral direction. Acid hydrolysis and milling did not substantially cut the “natural” chain length of cellulose fibrils. This cellulose longitudinal hierarchical model provides support for using weak acid hydrolysis in the production of cellulose nanofibrils with substantially reduced energy input without negatively affecting fibril mechanical strength.

  3. 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).

  4. 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

  5. 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.

  6. 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。

  7. 不同打浆设备对漂白针叶木浆纤维细纤维化程度的影响%Effects of different beating equipment on the degree of bleached softwood kraft pulp fiber′s fibrosis

    Institute of Scientific and Technical Information of China (English)

    徐永建; 王家泳; 闫瑛

    2015-01-01

    Bleached softwood kraft pulp was used as raw material to study the influence of varied pretreatment of on fluff pulp fiber ,by compareing the different beating equipment on the degree of pluff fiber fibrosis ,which was delt with different ways of beating preprocess‐ing .It turned out that ,water retention value increased by 7 .8% ,internal bond strength in‐creased by 31 .3% ,fiber single point of specific surface area increased by 12 .3% ,mean specif‐ic surface area increased by 12 .7% ,when compared with the fiber after groove beater beating pretreatment .PFI beating pretreatment showed a relative clear advantage on the realization of fiber fibrosis ,as well as the improvement of fiber absorbent .%以漂白针叶木硫酸盐浆作为原料,通过不同的打浆设备进行预处理,对比不同处理方式对纤维各项性能的影响,研究了打浆预处理对漂白针叶木纤维细纤维化程度的影响.结果表明,与槽式打浆处理相比,纤维经 PFI 预处理后保水值增加了7.8%,内结合强度增加了31.3%,纤维单点比表面积增加了12.3%,平均比表面积增加了12.7%.由此可知,PFI打浆预处理较槽式打浆方式更有利于纤维细纤维化,并提高了纤维的吸收性.

  8. Biobleaching of Paper Mulberry (Broussentia papyrifera) Pulp Using Laccase Mediator System

    OpenAIRE

    Sunita Chauhan; M. Krishna Mohan; Pradeep Bhatnagar

    2016-01-01

    In recent times, demand for cleaner production techniques in the handmade paper industry is on rise. Use of enzymes in prebleaching might be very useful in this regard. The laccase enzyme produced from Pycnoporus cinnabarinus was tested as an aid to the bleaching of paper mulberry (Broussentia papyrifera) pulp. For this, enzymatic prebleaching was carried out for two different durations i.e. 3 hours and 48 hours. The pulp was then subjected to chemical bleaching by hydrogen peroxide either...

  9. Biosynthesis of poly-beta-hydroxyalkanoates by Sphingopyxis chilensis S37 and Wautersia sp. PZK cultured in cellulose pulp mill effluents containing 2,4,6-trichlorophenol.

    Science.gov (United States)

    Tobella, Lorena M; Bunster, Marta; Pooley, Amalia; Becerra, José; Godoy, Felix; Martínez, Miguel A

    2005-09-01

    Poly-beta-hydroxyalkanoates (PHA) polymer is synthesized by different bacterial species. There has been considerable interest in the development and production of biodegradable polymers; however, the high cost of PHA production has restricted its applications. Kraft cellulose industry effluents containing 2,4,6-trichlorophenol (10 or 20 microg ml(-1)) were used by the bacteria Sphingopyxis chilensis S37 and Wautersia sp. PZK to synthesize PHA. In this condition, S. chilensis S37 was able to grow and degrade 2,4,6-trichlorophenol (ca. 60%) and 80% of these cells accumulated PHA. Wautersia PZK completely degraded 2,4,6-TCP and more than 90% of the cells accumulated PHA in 72 h. The PHA detection was performed by flow cytometry and polyester composition was characterized by gas chromatography-mass spectroscopy (GC-MS), indicating that these polymers are made by 3-hydroxybutyric acid and 3-hydroxyhexadecanoic acid for S37 and PZK strains, respectively. Results demonstrated that strains' growth and PHA production and composition are not modified in cellulose effluents with or without 2,4,6-TCP (10-20 microg ml(-1)). Therefore, our results indicate that S. chilensis S37 and Wautersia sp. PZK are able to degrade a toxic compound such as a 2,4,6-TCP and simultaneously produce a valuable biopolymer using low-value substrates.

  10. 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...

  11. 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.

  12. Xylanases of marine fungi of potential use for biobleaching of paper pulp

    Digital Repository Service at National Institute of Oceanography (India)

    Raghukumar, C.; Muraleedharan, U.; Gaud, V.R.; Mishra, R.

    bleaching of sugarcane bagasse pulp by a 60 min treatment at 55oC, resulting in a decrease of 10 kappa numbers and a 30% reduction in consumption of chlorine during bleaching process. The culture filtrate showed peaks of xylanase activity at acidic pH (3...

  13. 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.

  14. Structure-process-yield interrelations in nanocrystalline cellulose extraction

    Energy Technology Data Exchange (ETDEWEB)

    Hamad, W.Y.; Hu, T.Q. [FPInnovations, Vancouver, BC (Canada). Paprican Div.

    2010-06-15

    An understanding of the effect of hydrolysis conditions on yields of extracted water-insoluble cellulose materials is needed in order to understand the full potential of the extracted materials and the extent of their applications. This study provided a detailed analysis of the extraction of highly crystalline water-insoluble cellulose nanomaterials from commercial bleached kraft pulps using a sulfuric acid hydrolysis process. The process-yield-structure interrelations of the extracted materials were evaluated. The reproducibility of the hydrolysis process was evaluated, and methods of optimizing the yield of the extracted nanomaterials were explored. A Ruland-Rietveld analysis was used to resolve X-ray diffraction patterns and characterize crystallite size, crystalline and amorphous areas, and to determine the crystallinity of the extracted materials. The study showed that sulfation determines the yield of the materials and imparts the unique solid-state characteristics of the nanomaterials. The nanomaterials possessed iridescent patterns typical of chiral nematic materials. 27 refs., 3 tabs., 7 figs.

  15. 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.

  16. 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.

  17. Nonvital tooth bleaching: a review of the literature and clinical procedures.

    Science.gov (United States)

    Plotino, Gianluca; Buono, Laura; Grande, Nicola M; Pameijer, Cornelis H; Somma, Francesco

    2008-04-01

    Tooth discoloration varies in etiology, appearance, localization, severity, and adhesion to tooth structure. It can be defined as being extrinsic or intrinsic on the basis of localization and etiology. In this review of the literature, various causes of tooth discoloration, different bleaching materials, and their applications to endodontically treated teeth have been described. In the walking bleach technique the root filling should be completed first, and a cervical seal must be established. The bleaching agent should be changed every 3-7 days. The thermocatalytic technique involves placement of a bleaching agent in the pulp chamber followed by heat application. At the end of each visit the bleaching agent is left in the tooth so that it can function as a walking bleach until the next visit. External bleaching of endodontically treated teeth with an in-office technique requires a high concentration gel. It might be a supplement to the walking bleach technique, if the results are not satisfactory after 3-4 visits. These treatments require a bonded temporary filling or a bonded resin composite to seal the access cavity. There is a deficiency of evidence-based science in the literature that addresses the prognosis of bleached nonvital teeth. Therefore, it is important to always be aware of the possible complications and risks that are associated with the different bleaching techniques.

  18. Influence of post-bleaching time intervals on dentin bond strength.

    Science.gov (United States)

    Teixeira, Erica Cappelletto Nogueira; Turssi, Cecilia Pedroso; Hara, Anderson Takeo; Serra, Mônica Campos

    2004-01-01

    It has been reported that bond strength of resin to tooth structure can be reduced when the bonding procedure is carried out immediately after the bleaching treatment. This study evaluated the effect of bleaching of non-vital teeth bleaching on the shear bond strength (SBS) of composite resin/bovine dentin interface and the influence of delaying the bonding procedures for different time intervals following internal bleaching. According to a randomized block design, composite resin cylinders (Z100/Single bond - 3M) were bonded to the flattened dentin surface of two hundred and fifty-six teeth which had previously been subjected to four different treatments: SPH - sodium perborate + 30% hydrogen peroxide; SPW - sodium perborate + distilled water; CP - 37% carbamide peroxide; and CON - distilled water (control), each one followed by storage in artificial saliva for 0 (baseline), 7, 14, and 21 days after bleaching (n = 16). The bleaching agents in the pulp chambers were replaced every 7 days, over 4 weeks. The SBS test of the blocks was done using a universal testing machine. The ANOVA showed that there was no significant interaction between time and bleaching agents, and that the factor time was not statistically significant (p > 0.05). For the factor bleaching treatment, the Student's t-test showed that [CON = CP] > [SPW = SPH]. The bleaching of non-vital teeth affected the resin/dentin SBS values when sodium perborate mixed with 30% hydrogen peroxide or water was used, independently of the elapsed time following the bleaching treatment.

  19. 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.

  20. Extended oxygen delignification of high kappa softwood pulp in a flow-through reactor

    OpenAIRE

    Jafari, Vahid

    2015-01-01

    Julkaistu vain painettuna, saatavuus katso Bibid. Published only in printed form, availability see Bibid Oxygen delignification (O-delignification) is an important tool for improving yield, reducing lignin content of pulp and lowering the bleach chemical consumption in the pulp and paper industries. This process is designed after cooking to maximize the delignification rate in comparison to the final phase of Kraft cooking without sacrificing pulp quality. In order to improve the yield of ...

  1. 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 ...

  2. Optimization and selection of coagulating agents in the advanced treatment of washing & bleaching effluent from dissolving pulp process%溶解木浆中段废水深度处理中混凝剂的选择及优化

    Institute of Scientific and Technical Information of China (English)

    姜红梅; 毛长凤; 赵克侠

    2013-01-01

      溶解木浆中段废水先经模拟好氧生化系统处理后,采用混凝法进行深度处理试验。结果表明:硫酸铝适用于溶解木浆废水深度治理,并在废水处理效果及处理成本方面优于聚合氯化铝、聚合硫酸铁、氯化铁等无机絮凝剂。硫酸铝投加后pH值在6~7范围内,搭配阴离子PAM去除浊度的效果更明显。生化模拟试验出水作为混凝原水,先经预酸化再好氧生化水质的混凝处理效果优于好氧生化的水质:处理后出水COD<100mg/L,色度<50倍;单耗处理成本更低,处理成本降低0.264~0.44元。%The washing&bleaching effluent of dissolving pulp was first treated with simulated aerobic biochemical process, advanced treatment was done by coagulation process. The results show that aluminum sulfate is suitable for dissolving pulp wastewater advanced treatment, with which the treating effect and the treating cost are better than that of polymeric aluminum chloride, poly ferric sulfate, ferric chloride and other inorganic flocculants. When aluminum sulfate is added with the combination of anionic PAM, pH range of 6~7, turbidity removal effect is more obvious. The waste water treated first by pre-acidification and aerobic biochemical process has a better treating effect in coagulation than the waste water treated only by aerobic biochemical process, reaching COD less than 100mg/L, chroma less than 50 times, with the treatment cost reduced by 0.264~0.44 yuan/t.

  3. 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

  4. 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.

  5. Can Acceptable Pulp be Obtained from Eucalyptus globulus Wood Chips after Hemicellulose Extraction?

    Directory of Open Access Journals (Sweden)

    Francisco López

    2014-11-01

    Full Text Available This study investigates the operating conditions used in the soda-anthraquinone pulping of Eucalyptus globulus wood after autohydrolysis pretreatment on the yield, kappa number, and brightness of the resulting unbleached pulp. Moreover, strength-related properties of the resulting handsheets was examined to identify the best pulping conditions and compare the outcome with that of a conventional soda-anthraquinone pulping process. The paper strength properties of the pulp were similar to or better than papers made from soda-AQ delignified pulps conducted in a single step. Also, a liquid fraction with a substantial content in hemicellulosic extracts was recovered in the simplified process. Autohydrolysis of the raw material facilitates carrying out soda-AQ pulping under milder conditions. In addition, autohydrolysis improves other properties relative to paper from raw cellulose pulp. Yield, kappa number, and brightness for pulp from solid residues of autohydrolysed eucalyptus wood were similar to those for pulp from untreated eucalyptus wood.

  6. Evaluation of cotton-fabric bleaching using hydrogen peroxide and Blue LED

    Science.gov (United States)

    de Oliveira, Bruno P.; Moriyama, Lilian T.; Bagnato, Vanderlei S.

    2015-06-01

    The raw cotton production requires multiple steps being one of them the removal of impurities acquired during previous processes. This procedure is widely used by textile industries around the world and is called bleaching. The raw cotton is composed by cellulosic and non-cellulosic materials like waxes, pectins and oils, which are responsible for its characteristic yellowish color. The bleaching process aims to remove the non-cellulosic materials concentration in the fabric, increasing its whiteness degree. The most used bleaching method utilizes a bath in an alkali solution of hydrogen peroxide, stabilizers and buffer solutions under high temperature. In the present study we evaluated the possibility of using a blue illumination for the bleaching process. We used blue LEDs (450 nm) to illuminate an acid hydrogen peroxide solution at room temperature. The samples treated by this method were compared with the conventional bleaching process through a colorimetric analysis and by a multiple comparison visual inspection by volunteers. The samples were also studied by a tensile test in order to verify the integrity of the cloth after bleaching. The results of fabric visual inspection and colorimetric analysis showed a small advantage for the sample treated by the standard method. The tensile test showed an increasing on the yield strength of the cloth after blue light bleaching. The presented method has great applicability potential due to the similar results compared to the standard method, with relative low cost and reduced production of chemical waste.

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

    Science.gov (United States)

    Arif, S.; Kautek, W.

    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.

  8. Potential Applications of Hybrid Layered Double Hydroxide (LDH Particles in Pulp and Paper Production

    Directory of Open Access Journals (Sweden)

    Sophia von Haartman

    2014-03-01

    Full Text Available Functionalization of papermaking pulp fibers using inorganic particles was investigated as a novel approach. Different layered double hydroxide (LDH particles were used in peroxide bleaching of thermomechanical pulp (TMP and in oxygen bleaching of eucalyptus kraft pulp. LDH particles were also tested as binding sites for optical brightening agents (OBA that are commonly used in paper production. The surface chemistry of LDH-treated pulps was examined using X-ray photoelectron spectroscopy (XPS and apparent contact angle with water. Adsorbed LDH was not detected by XPS on the fiber surfaces after the bleaching trials, but it had a clear impact on the processes. LDH particles modified with terephthalate anions decreased the consumption of hydrogen peroxide and increased opacity by 3 units in TMP. Unmodified LDH particles enhanced the selectivity in oxygen delignification of kraft pulp, leading to 10% gain in ISO brightness and reduction of 2 units in Kappa number in comparison with conventional processes. Paper strength properties were unaffected in the presented system. After bleaching with LDH, the amount of anionic groups on pulp surfaces was increased. Also, the retention of OBA onto TMP fibers was improved with modified LDH particles. LDH proved to have great potential for current and prospective applications in pulp and paper manufacture.

  9. 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.

  10. 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.

  11. Magnetic Alignment of Cellulose Nanowhiskers in an All-Cellulose Composite

    Energy Technology Data Exchange (ETDEWEB)

    Li, Dongsheng; Liu, Zuyan; Al-Haik, Marwan; Tehrani, Mehran; Murray, Frank; Tennenbaum, Rina; Garmestani, Hamid

    2010-08-01

    Unidirectional reinforced nanocomposite paper was fabricated from cellulose nanowhiskers and wood pulp under an externally-applied magnetic field. A 1.2 Tesla magnetic field was applied in order to align the nanowhiskers in the pulp as it was being formed into a sheet of paper. The magnetic alignment was driven by the characteristic negative diamagnetic anisotropy of the cellulose nanowhiskers. ESEM micrographs demonstrated unidirectional alignment of the nanowhiskers in the all-cellulose composite paper. Comparing with control paper sheets made from wood pulp only, the storage modulus in the all-cellulose nanocomposites increased dramatically. The storage modulus along the direction perpendicular to the magnetic field was much stronger than that parallel to the magnetic field. This new nanocomposite, which contains preferentially-oriented microstructures and has improved mechanical properties, demonstrates the possibility of expanding the functionality of paper products and constitutes a promising alternative to hydrocarbon based materials and fibers.

  12. Biobleaching of Paper Mulberry (Broussentia papyrifera Pulp Using Laccase Mediator System

    Directory of Open Access Journals (Sweden)

    Sunita Chauhan

    2016-12-01

    Full Text Available In recent times, demand for cleaner production techniques in the handmade paper industry is on rise. Use of enzymes in prebleaching might be very useful in this regard. The laccase enzyme produced from Pycnoporus cinnabarinus was tested as an aid to the bleaching of paper mulberry (Broussentia papyrifera pulp. For this, enzymatic prebleaching was carried out for two different durations i.e. 3 hours and 48 hours. The pulp was then subjected to chemical bleaching by hydrogen peroxide either directly (LP sequence or after an alkaline extraction stage (LEP sequence. The synergistic effect of xylanase enzyme on laccase mediator system was also evaluated and found to be negligible. Under the defined conditions, a gain of up to ten points in brightness value of the treated pulps as compared to the control pulps could be obtained. Thus, laccase mediator system was found to be very effective in boosting the brightness of paper mulberry pulp.

  13. 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.

  14. 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…

  15. Investigating the possibility of chemi-mechanical pulping of bagasse

    Directory of Open Access Journals (Sweden)

    Alireza Khakifirooz

    2013-02-01

    Full Text Available Chemi-mechanical pulping was evaluated as a potential way to prepare sugarcane bagasse fibers for papermaking. Cellulose, lignin, ash, and extractives soluble in alcohol-acetone were measured as 55.75%, 20.5%, 1.85%, and 3.25%, respectively. Fiber length, diameter, lumen cavity, and cell wall thickness were measured as 1.59 mm, 20.96, 9.72, and 5.64 µm. The chemi-mechanical pulping conditions were selected as follows: three charging levels of 10, 15, and 20% sodium sulphite, and three pulping times of 20, 30, and 40 minutes after reaching the pulping temperature. Pulping temperature was held constant at 165 C. Different pulping conditions resulted in pulp yields between 65.38 and 84.28%. The highest yield (84.28% was obtained using a treatment combination of 20 minutes pulping time and 10% sodium sulphite. The lowest yield (65.38% was related to 40 minutes pulping time and 20% sodium sulphite. Pulps were refined to 300 ± 25 mL CSF, 60 gm-2 handsheets were made, and then strength indices and optical properties of the handsheets were measured. The results showed that 20% sodium sulphite, 40 minutes pulping time, at 165 ºC can be considered as the optimum pulping conditions for bagasse CMP pulping. Tensile, tear, and burst strength indices, as well as the opacity of this pulp were measured as 39.59 Nmg-1, 6.66 mNm2g-1, 2.1 KPa m2g-1, and 95.35%, respectively.

  16. Bleaching of Wool with Sodium Borohydride

    Directory of Open Access Journals (Sweden)

    Duygu Yilmazer, MSc.

    2009-09-01

    Full Text Available An untreated wool fabric was bleached both with sodium borohydride (SBH in the presence of sodium bisulphite (SBS solution and with a commercial H2O2 bleaching method. The concentration effects of SBH and SBS, bleaching time, pH and temperature on SBH bleaching process were investigated. Whiteness, yellowness and alkali solubility results were assessed for both bleaching methods. The results showed that whiteness degrees obtained with SBH bleaching was comparable with that of H2O2 bleaching method; whereas the alkali solubility values of the SBH bleaching was superior to the H2O2 bleaching.

  17. 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.

  18. TECHNOLOGICAL CHARACTERIZATION OF Eucalyptus benthamii WOOD FOR KRAFT PULP PRODUCTION

    Directory of Open Access Journals (Sweden)

    Isabel Cristina Nogueira Alves

    2011-03-01

    Full Text Available The purpose of this study was to evaluate the quality of Eucalyptus benthamii wood for kraft pulp production. A hybrid of Eucalyptus urophylla x Eucalyptus grandis, probably the most planted Eucalyptus clone in Brazil, was also analyzed for comparison purposes. Basic density, chemical composition and fiber dimensions were determined for the two species. The Eucalyptus benthamii wood presented an anatomical structure, basic density and fiber dimensions quite similar to those of other species planted by the Brazilian pulp industry. However, it presented poorer wood quality characteristics when compared to the hybrid urograndis species, with higher amounts of extractives and lignin, lower amount of glucans, more galactans and lower S/G ratio, characteristics leading to lower pulping yield. Additional studies should be carried out to establish its pulping, bleaching and paper strength properties.

  19. 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.

  20. APPLICATION OF NSSC PULPING TO SUGARCANE BAGASSE

    Directory of Open Access Journals (Sweden)

    Alireza Khakifirooz

    2011-06-01

    Full Text Available The NSSC pulping process was investigated to produce pulp from bagasse for corrugating board manufacture. The chemical contents including cellulose, lignin, ash, and extractives soluble in alcohol-acetone measured 55.75, 20.5, 1.85, and 3.25, respectively. The average fiber length, fiber diameter, lumen width, and cell wall thickness of bagasse were 1.59 mm, 20.96, 9.72, and 5.64 μm, respectively. The optimum conditions, with a yield of 74.95%, were achieved using 20 percent chemicals on the basis of sodium oxide, cooking temperature of 170 °C, and cooking time of 30 minutes. Pulp was refined to freeness 345 and 433 mL CSF according to Canadian standards. 127 g m-2 handsheets from both pulps were made and strength properties measured. Statistical analysis of results indicated that paper derived from freeness 345 and 433 mL CSF had better strength properties in all indices in comparison with NSSC pulp from hardwoods produced at Mazandaran Pulp and Paper factory, Iran.

  1. Endurance of high molecular weight carboxymethyl cellulose in corrosive environments

    Science.gov (United States)

    Murodov, M. M.; Rahmanberdiev, G. R.; Khalikov, M. M.; Egamberdiev, E. A.; Negmatova, K. C.; Saidov, M. M.; Mahmudova, N.

    2012-07-01

    Lignin obtained from the waste cooking liquor, formed after soda pulping process, is used as an inhibitor of NaCMC thermo oxidative degradation in presence of in extreme conditions during drilling oil wells. In this paper the schematic process of obtaining NaCMC by the principle of "monoapparat" on the basis of cellulose produced by non-wood cellulose materials is presented.

  2. 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.

  3. 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.

  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. 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.

  6. 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.

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

    Directory of Open Access Journals (Sweden)

    Yao Chen,

    2012-02-01

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

  8. 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.

  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. Evaluation of shear bond strength of orthodontic brackets bonded on the tooth surface after internal bleaching

    Directory of Open Access Journals (Sweden)

    Nadia de Souza FERREIRA

    Full Text Available Introduction: There is great demand for esthetic treatment by patients who have discolored teeth, because currently aesthetic standards have become stricter and many patients have tooth bleaching procedures performed before or during orthodontic treatment. Objective: To evaluate the bonding of orthodontic brackets to human molars after internal tooth bleaching. Material and method: Forty molars were divided into four groups according to the bleaching agent used: PS sodium perborate + water; PC carbamide peroxide; PC + PS carbamide peroxide + sodium perborate; Cont water (control group. Bleaching agents placed inside the pulp chambers were replaced every 7 days for 2 weeks, and the brackets were bonded 30 days after the end of bleaching. The shear strength test was performed in a universal testing machine (Emic. Result: ANOVA with a significance level of 5% (p > 0.05, showed no statistically significant difference between groups (p = 0.1214. Conclusion: It was concluded that the different bleaching agents studied did not interfere with the bond strength of brackets to enamel and bonding the brackets 30 days after internal bleaching is a safe procedure.

  11. Reducing sugar production of sweet sorghum bagasse kraft pulp

    Science.gov (United States)

    Solihat, Nissa Nurfajrin; Fajriutami, Triyani; Adi, Deddy Triyono Nugroho; Fatriasari, Widya; Hermiati, Euis

    2017-01-01

    Kraft pulping of sweet sorghum bagasse (SSB) has been used for effective delignification method for cellulose production. This study was conducted to evaluate the performance pulp kraft of SSB for reducing sugar production. The study intended to investigate the effect of active alkali and sulfidity loading variation of SSB pulp kraft on reducing sugar yield per biomass. The SSB pulp was prepared after pulping using three variations of active alkali (17, 19, and 22%) and sulfidity loading (20, 22, and 24%) at 170°C for 4 h with liquor to wood ratio of 10. A total of 9 pulps were obtained from these pretreatments. Delignification pretreatment has been succesfully removed lignin and hemicellulose more than 90% and 50%, respectively. Increasing active alkali and sulfidity loading has significantly increased lignin removal caused by disruption of the cell wall structure for releasing lignin into black liquor in the cellulose extraction. The enzymatic hydrolysis of pulp was carried out with cellulase loading of 40 FPU per g substrate in the shaking incubator at 50°C and 150 rpm for 78 h. For each 24 h, the reducing sugar yield (DNS assay) has been observed. Even though the lignin and hemicellulose loss occurred along with higher active alkali loading, this condition tends to decrease its yield. The reducing sugar concentration varied between 7-8 g/L. Increasing active alkali and sulfidity was significantly decreased the reducing sugar per biomass. Pulp delignified by 17% active alkali and 20% sulfidity has demonstrated the maximum reducing sugar yield per biomass of 45.57% resulted after 72 h enzymatic hydrolysis. These results indicated that kraft pulping was success to degrade more lignin and hemicellulose content to facilitate the enzyme for breaking down the cellulose into its sugar monomer. A high loss of lignin and hemicellulose are not single factor to improve digestibility of SSB. This sugar has potential for yeast fermented into bioethanol.

  12. 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.

  13. 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.

  14. 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.

  15. 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 (p<0.05). MAX showed severe inflammation in the upper thirds of the coronal pulp, and BLU showed moderate inflammation (p<0.05). In-office bleaching 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.

  16. Bio-modification of eucalyptus chemithermomechanical pulp

    Institute of Scientific and Technical Information of China (English)

    Qifeng YANG; Huaiyu ZHAN; Shuangfei WANG; Kecheng LI; Shiyu FU

    2008-01-01

    Eucalyptus chemithermomechanical pulp (CTMP) was modified with the white-rot fungus 19-6 in a stationary culture condition. Different factors that influence the effect of white-rot fungus treatment, including additional nutrition, pH value, temperature, treatment time and oxygen input were investigated. The results show that the energy consumption of post refining of CTMP treated by white-rot fungus 19-6 was lower than that of untreated pulp and the strength properties also obviously improved. At a freeness level of about 330 mL, compared to the untreated pulp, the tensile index, tear index and internal bonding strength increased by 21.3%, 27.4% and 33.1%, respectively. Unfortunately, the treatment with white-rot fungus substantially decreased all optical properties except for opacity, which was essentially unchanged. Brightness and light scatter-ing coefficient were reduced to as much as 25% and 21% compared to the untreated pulps. However, after a tow-stage "Na2S2O4H2O2" bleaching, the final brightness can reach 70.3% ISO, which is similar to that of the untreated CTMP.

  17. 辐射和过氧乙酸综合预处理纸浆,改善全无氯漂白选择性%Application of photo, peracetic acid, and combination pre-treatments in improving totally chlorine-free bleaching selectivity

    Institute of Scientific and Technical Information of China (English)

    苗成; 刘忠

    2015-01-01

    selectivity by protecting the cellulose from carbonyl-induced degradation. This protective effect was more prominent in the O-stage than the Op-stage. However, the combination of peracetic acid and photo treatment did not further increase bleaching selectivity in either stage. In short, blue light and UV irradiation treatment with or without the prior addition of peracetic acid to ordinary or hydrogen peroxide-reinforced oxygen deligniifed pulp displayed a similar bleaching effect on the resultant pulp.

  18. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    None

    1977-05-01

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

  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. 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).

  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. REINFORCING POTENTIAL OF JUTE PULP WITH TREMA ORIENTALIS (NALITA) PULP

    OpenAIRE

    Sabina Rawshan; M. Sarwar Jahan

    2009-01-01

    Two morphologically different pulps, a long-fiber jute pulp from a soda-AQ process and a short-fiber Trema orientalis pulp from a kraft process, were evaluated and compared for their reinforcing potential. T. orientalis pulp needed less beating energy than jute pulp at the same drainage resistance. Addition of jute fiber pulp to the T. orientalis pulp increased tear strength. Sheet density of pulp blends was increased with the increase of beating degree of both pulps and the proportion of T. ...

  5. 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

  6. 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...... to illustrate the morphology of MFC nanofibers in pure films and in an amylopectin matrix. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-07-01

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

  8. Dental Pulp Testing: A Review

    OpenAIRE

    Eugene Chen; Abbott, Paul V

    2009-01-01

    Dental pulp testing is a useful and essential diagnostic aid in endodontics. Pulp sensibility tests include thermal and electric tests, which extrapolate pulp health from sensory response. Whilst pulp sensibility tests are the most commonly used in clinical practice, they are not without limitations and shortcomings. Pulp vitality tests attempt to examine the presence of pulp blood flow, as this is viewed as a better measure of true health than sensibility. Laser Doppler flowmetry and pulse o...

  9. 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.

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

    Directory of Open Access Journals (Sweden)

    Elenice Pereira Maia

    2003-04-01

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

  11. 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.

  12. 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.

  13. Stellera chamaejasme Roots as Raw Material for Pulp Production

    Directory of Open Access Journals (Sweden)

    Haichao Li

    2014-06-01

    Full Text Available Cellulosic pulps were prepared from Stellera chamaejasme roots using soda, soda-anthraquinone (soda-AQ, and kraft pulping processes. S. chamaejasme is composed of 73.5% holocellulose, 39.7% α-cellulose, and 17.6% lignin, similar to wheat straw and other non-wood plant materials. The ethanol–benzene extractives content of 9.2% is higher than other non-woods. The conditions used for all pulping experiments were as follows: a liquid/solid ratio of 5:1; a time-to-maximum temperature of 100 min; a maximum temperature of 160 °C; and a time-at-maximum temperature of 50 min. The results showed that the pulp yield was 31.27 to 36.83%, the kappa number was 16.32 to 19.42, and the pulps’ intrinsic viscosity was 854 to 976 mL/g. Tear index, tensile index, burst index, and brightness of the papers made from the above unbleached pulps were 12.60 to 13.62 mN•m2/g, 20.57 to 22.56 mN/g, 2.16 to 2.38 kPa•m2/g, and 15.3 to 18.3%, respectively.

  14. 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

  15. Cellulose is not just cellulose

    DEFF Research Database (Denmark)

    Hidayat, Budi Juliman; Felby, Claus; Johansen, Katja Salomon

    2012-01-01

    or enzymatic hydrolysis of plant cell walls is carried out simultaneously with the application of shear stress, plant cells such as fibers or tracheids break at their dislocations. At present it is not known whether specific carbohydrate binding modules (CBMs) and/or cellulases preferentially access cellulose......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...... are not regions where free cellulose ends are more abundant than in the bulk cell wall. In more severe cases cracks between fibrils form at dislocations and it is possible that the increased accessibility that these cracks give is the reason why hydrolysis of cellulose starts at these locations. If acid...

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

    Science.gov (United States)

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

    1999-04-01

    Bleaching vital teeth with 10% carbamide peroxide gel is a routine procedure in which there has been no evidence of associated permanent pulpal damage. Synthesis of the enzyme heme oxygenase-1 (HO-1) is increased after exposure of eukaryotic cells to conditions of oxidative stress (including H2O2) as a defense against the damaging effects of free radicals. Dental pulps were evaluated for HO-1 (aka Heat Shock Protein 32) presence in teeth treated with 10% carbamide peroxide. Seventeen intact first premolars scheduled for orthodontic extraction were bleached for 4 h immediately preceding extraction. Fourteen additional premolars from the same individuals were not bleached. All 31 teeth were extracted, fixed, demineralized, frozen, sectioned, and immunostained with anti-HO-1 antibody using a standard ABC protocol. There was no significant difference in the presence of HO-1 between total bleached versus total unbleached teeth using the Fisher's Exact Test (p < or = 0.05). However, the histological findings could be interpreted to suggest that coronal odontoblasts and endothelial cells in the underlying pulp proper may have the potential to respond to oxidative stress by increasing the synthesis of HO-1 (HSP32). This could represent a component of an initial defensive response by specific cells in strategic locations in the pulp that precedes classical inflammatory pathways.

  17. Morphological and Chemical Characterization of Green Bamboo (Dendrocalamopsis oldhami (Munro Keng f. for Dissolving Pulp Production

    Directory of Open Access Journals (Sweden)

    Shilin Cao

    2014-06-01

    Full Text Available With the sustained growth of dissolving pulp demand all over the world, the search for alternative bamboo materials has come into focus in China due to the shortage of wood and the abundance of bamboo resources. In this study, to obtain updated information concerning green bamboo growing in southeastern China and to develop its processing technologies for dissolving pulp, the fiber morphology, chemical composition, elemental composition, degree of polymerization (DP of cellulose, and crystallinity index (CrI of cellulose were investigated. The experimental results show that green bamboo has potential for use as dissolving pulp because it has a lower Runkel ratio and fines content than moso bamboo, and a much lower lignin content and similar α-cellulose and hemicellulose contents compared to softwoods and hardwoods. Compared to the cortex and culm, the node had the shortest fibers and more than 30% of fines, the highest content of extractives and lignin, and the lowest α-cellulose content. As a result, a de-knotting operation prior to cooking can contribute to the production of high-grade dissolving pulp. The DP and CrI of cellulose from the node were much lower than that of cellulose from the culm and cortex. Moreover, green bamboo had the high content of ash, primarily distributed in the cortex. The concentration of Si was 4487 ppm in the cortex, nearly five times higher than that in the culm and node.

  18. 21 CFR 582.1975 - Bleached beeswax.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Bleached beeswax. 582.1975 Section 582.1975 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1975 Bleached beeswax. (a) Product. Bleached beeswax (white wax). (b) Conditions of...

  19. Comparative toxicities of oxygen, ozone, chlorine dioxide, and chlorine bleaching filtrates - microtox toxicities of raw and processed filtrates

    Energy Technology Data Exchange (ETDEWEB)

    Ard, T.A.; McDonough, T.J.

    1995-12-31

    It has claimed that effluents from the bleaching of kraft pulp with chlorine and its compounds have deleterious effects on the aquatic environment. It has been further suggested that bleaching without the use of chlorine or its compounds will produce innocuous effluents. To obtain information on the validity of these claims, we have conducted a laboratory study of the toxicity of filtrates from chlorine-based and nonchlorine bleaching processes. We have also examined two related issues. The first is whether any toxicants generated during bleaching are rendered harmless (by neutralization, storage, and biological treatment) before being discharged to the environment. The second related issue is whether any toxicity observed in mill effluents actually originates in the bleaching process, as opposed to being due to raw material components or compounds formed during the pulping step that precedes bleaching. Several conclusions were drawn from this study. (1) There is a background level of toxicity which originates in the oxygen stage, process steps prior to bleaching, or in the wood raw material. It is decreased by neutralization and storage, but residual toxicity may still be detected after two weeks. (2) If the sum of the first and second stage toxicities is taken as an indicator of overall toxicity, the untreated filtrates may be ranked as follows: Control (Background) > D(EO) > Z(EO) > C(EO). However, these toxicities are of no importance in regard to environmental effects because of their ephemeral nature and the likelihood of their being reduced or eliminated prior to effluent discharge. Evidence for this statement is the ease with which all except the C(EO) were detoxified by neutralization and storage. (3) After neutralization and storage for two weeks at room temperature the ranking of toxicities becomes: C(EO) > D(EO) > Z(EO) > Background. The last three are similar in magnitude.

  20. Rheological study of cellulose dissolved in aqueous ZnCl2 : Regenerated cellulosic fibres for textile applications

    OpenAIRE

    Ulfstad, Louise

    2013-01-01

    The most known regenerated cellulosic fiber is viscose, produced in a wet spinning process, but due to cost and environmental issues other processes have been developed. Lyocell fibers, produced in air-gap spinning, have superior dry and wet strenght and a lower environmental impact compared to viscose. Research in different cellulose solvent has increased significantly tha last decadess, due to an increased cotton price and a decreased paper production, providing more wood pulp to production...

  1. 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.

  2. Effect of pulping variables with dimethyl formamide on the characteristics of bagasse-fiber.

    Science.gov (United States)

    Rezayati-Charani, P; Mohammadi-Rovshandeh, J

    2005-10-01

    Organosolv pulping of bagasse was conducted following a central composite design using a two-level factorial plan involving three pulping variables (temperature: 190-210 degrees C, time: 120-180 min, organic solvent ratio: 40-60% dimethyl formamide). Responses of pulp and handsheets properties to the process variables were analyzed using statistical software (MINITAB 14). Using values of the independent variables the variation ranges considered provided the following optimum values of the dependent variables: 82.7% (yield), 92.9 (kappa number), 1.403% (ash), 370 ml (freeness), 6290 m (breaking length), 9.4 (folding endurance), 5.955 mN m2 g(-1) (Tear index) and 2.811 kN g(-1) (Burst index) for pulps and handsheets. Results showed that acceptable physical and mechanical properties of pulps and papers similar the pulp used for bleaching could be achieved at 210 degrees C for 150 min and 50% DMF. These are the most suitable conditions for obtaining paper sheets with a high breaking length, tear and burst indices. Also bagasse could be pulped with ease to about 55.72% yield with kappa number approximately 35. The cooking temperature was a significant factor while the DMF ratio and cooking time were not as important in term of the properties of the resultant pulps and papers.

  3. Potential of thermo and alkali stable xylanases from Thielaviopsis basicola (MTCC-1467) in biobleaching of wood kraft pulp.

    Science.gov (United States)

    Goluguri, Baby Rani; Thulluri, Chiranjeevi; Cherupally, Madhu; Nidadavolu, Nagaraju; Achuthananda, Das; Mangamuri, Lakshmi Narasu; Addepally, Uma

    2012-08-01

    Thermo- and alkali-stable xylanases produced from Thielaviopsis basicola (MTCC-1467) on low-cost carbon source like rice straw were evaluated for their potential application in biobleaching of wood kraft pulp. Enzyme treatment at retention time of 240 min with 20 IU/gm of dried pulp resulted in ~85.2 % of reduction in kappa number. When compared to control, 110.8, 93, and 72.2 % of enhancement in brightness (percent International Organization of Standardization), whiteness, and fluorescence, respectively, were observed for enzyme-treated pulp. Spectroscopic analysis showed significant release of chromophoric compounds from enzyme-treated pulp. Furthermore, scanning electron microscope studies of unbleached and enzyme bleached pulp revealed the effectiveness of enzymatic treatment. The enzyme-treated pulp subjected to later stages of chemical bleaching resulted in 16 % decrease in chlorine consumption along with considerable reduction in chemical oxygen demand percentage (14.5 %) level of effluent. Various pulp properties like fiber length, fiber width, burst strength, burst index, tear strength, tear index, tensile strength, and breaking length were also significantly improved after enzyme treatment when compared to control.

  4. 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.

  5. 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.

  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

    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

  7. Utilization of a chemical-mechanical pulp with improved properties from poplar wood in the composition of packing papers

    Directory of Open Access Journals (Sweden)

    Spiridonov, I.

    2007-02-01

    Full Text Available The aim of the present work is to obtain a chemical-mechanical pulp (CMP from poplar wood with improved properties, to be used in packing papers in place of more expensive softwood or hardwood pulp. For improving the CMP quality indicators, a preliminary treatment of the pulp has been carried out with a mixture of oxidizing enzymes produced from Phanerochaete chrysosporium, including lignin peroxidase, manganese peroxidase, and laccase. The two types of fiber materials obtained were double-stage bleached and then ground to 30oSR. It was found that preliminary enzyme treatment yielded CMP with improved physical, mechanical, and optical properties. The enzyme-pretreated CMP also refined faster, thus reducing the electricity consumption. Bleached CMP from poplar wood, obtained after preliminary enzyme treatment, could be successfully utilized at levels up to 40% in the composition of various packaging papers.

  8. 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

  9. Soda pulp and fuel gases synthesis from Hesperaloe funifera.

    Science.gov (United States)

    Sánchez, Rafael; Rodríguez, Alejandro; Requejo, Ana; Ferrer, Ana; Navarro, Enrique

    2010-09-01

    The main objective of this work is to evaluate the suitability of Hesperaloe funifera which is an alternative raw material, for pulping with soda-anthraquinone to produce pulp and paper. It was studied the influence of operational variables (temperature (155-185 degrees C), cooking time (20-60 min) and soda concentration (5-15%), with a constant addition of 1% of anthraquinone and a liquid/solid ratio of 8, in soda-anthraquinone cooking of H. funifera on pulps and paper sheets properties obtained. Finally, the cooking liquors were acidified to separate solid fractions that were subjected to pyrolysis and gasification in order to obtain synthesis and fuel gases. H. funifera contains little lignin and abundant alpha-cellulose; this, together with the morphological characteristics of its fibers, makes it a potentially highly useful papermaking raw material.

  10. A new use for TCF pulp with a high hexenuronic acid content

    OpenAIRE

    Valls Vidal, Cristina; Roncero Vivero, María Blanca

    2013-01-01

    The importance of HexA groups lies on their influence on the bleaching process and the properties of the resulting pulp. In this work, various aspects of HexA were examined in order to elucidate their role in eucalyptus fibres. Thus, the contribution of HexA to kappa number in eucalyptus pulp was estimated to be 1.05 units per 10 μmol of HexA. Also, HexA changes during an ECF and a TCF sequence were examined in relation to lignin. Interesting results were found by comparing the boosting effec...

  11. Optimization of biobleaching of paper pulp in an expanded bed bioreactor with immobilized alkali stable xylanase by using response surface methodology.

    Science.gov (United States)

    Senthilkumar, Sundar Rajan; Dempsey, Michael; Krishnan, Chandraraj; Gunasekaran, Paramasamy

    2008-11-01

    Purified alkali stable xylanase from Aspergillus fischeri was immobilized on polystyrene beads using diazotization method. An expanded bed bioreactor was developed with these immobilized beads to biobleach the paper pulp in continuous mode. Response surface methodology was applied to optimize the biobleaching conditions. Temperature (degrees C), flow rate of pulp (ml/min) and concentration of the pulp (%) were selected as variables in this study. Optimal conditions for biobleaching process were reaction temperature 60 degrees C, flow rate of 2 ml/min and 5% (w/v) of pulp. The kappa number reduced from 66 in the unbleached pulp to 20 (reduction of 87%). This system proves to be a better option for the conventional chlorine based pulp bleaching.

  12. 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.

  13. 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.

  14. 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.

  15. DELIGNIFICATION OF SUGARCANE BAGASSE WITH ALKALI AND PERACETIC ACID AND CHARACTERIZATION OF THE PULP

    Directory of Open Access Journals (Sweden)

    Ting Zhang

    2010-06-01

    Full Text Available Sugarcane bagasse was delignified with alkali and peracetic acid in a two-stage process to obtain pulps with high yield and low kappa number. The experimental results indicated that alkali pretreatment prior to peracetic acid (PAA delignification could significantly reduce PAA loading by partially removing lignin and swelling the fibers. An optimum condition for the two-stage delignification was obtained for pulping of sugarcane bagasse. The pulps were further characterized by chemical composition analysis, strength property tests, Fourier Transform Infrared Spectroscopy (FTIR, X-Ray Diffraction (XRD, and Thermal Gravimetric Analysis (TGA. It was found that the alkali-PAA process could be conducted under milder conditions with resulting higher pulping selectivity, higher degree of polymerization (DP, and superior mechanical properties of pulps, compared to the kraft pulping process. Both kraft pulps and alkali-PAA pulp had similar FTIR spectra, XRD spectra, and TGA (DTG curves. However, further analysis indicated that the alkali-PAA pulp had higher infrared crystallization index and cellulose crystallinity.

  16. DEVELOPMENT OF A NOVEL EMPIRICAL MODEL TO ESTIMATE THE KRAFT PULP YIELD OF FAST-GROWING EUCALYPTUS

    Directory of Open Access Journals (Sweden)

    Jing Liu,

    2012-01-01

    Full Text Available In this study, several kraft pulps were produced by kraft pulping of fast-growing Eucalyptus with a wide range of cooking conditions. The dependences between pulp yields and some pulp properties, namely, kappa number, HexA contents, and cellulose viscosities, were well investigated. It was found that kraft pulp yields linearly decreased with the reduction of HexA-free kappa number in two different stages, respectively, in which a transition point of measured pulp yield of 48.7% was observed. A similar relationship between pulp yield and HexA was also found, in which the resulting transition point of HexA content was 67 μmol/g. Moreover, the logarithm of pulp viscosity was linearly proportional to the reduction of lignin-free pulp yields. Then, a novel empirical model was successfully developed based on these findings. The parameters in this empirical model were calculated by least-squares estimation using the experimental data from active alkali values of 13.2, 14.7 and 17.8. Another data set was used to verify the effectiveness of this model in predicting the pulp yields. Finally, a good agreement (a linear regression coefficient of 90.59% between experimental and fitting data was obtained, which indicated that the kraft pulp yield of fast-growing Eucalyptus could be accurately predicted by this novel empirical model.

  17. Nano-fibrillation of pulp fibers for the processing of transparent nanocomposites

    Science.gov (United States)

    Iwamoto, S.; Nakagaito, A. N.; Yano, H.

    2007-11-01

    Pulp fibers were fibrillated uniformly into nano-sized fibers using a grinder with a specially designed set of grinding disks. To investigate the effect of the fibrillation through the grinder on the physical properties of the composites, dissolved pulp fibers were subjected to various passes through the grinder, and the resulting fibrillated pulp fibers were used to make fibrillated pulp fibers/acrylic resin composites. Scanning electron microscopy observations showed that at above five passes, the structure of the fibrillated pulp fibers did not change significantly. The light transmittances of the composites were increased to 80% up to five passes through the grinder, and did not change after further passes. However, the tensile test and thermal expansion analysis indicated that a degradation of the fibrillated pulp occurred during the grinding treatment. To evaluate the fiber degradation, the degree of crystallinity and degree of polymerization of cellulose were measured. Both decreased as the number of passes through the grinder increased. In addition, to reduce the thermal expansion of composites, the fibrillated pulp fibers were additionally treated by sulfuric acid. The thermal expansion of composites was decreased, because the amorphous region of cellulose was removed.

  18. Bleaching and recovery patterns of corals in Palk Bay, India: An indication of bleaching resilient reef

    Digital Repository Service at National Institute of Oceanography (India)

    Manikandan, B.; Ravindran, J.; Vidya, P.J.; ManiMurali, R.

    Frequency and severity of coral bleaching events increased in recent years affecting the recovery and resilience of corals. In this study, influence of bleaching and recovery patterns of corals on the resilience potential of Palk Bay reef...

  19. 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.

  20. Titanium dioxide-cellulose hybrid nanocomposite based conductometric glucose biosensor

    Science.gov (United States)

    Maniruzzaman, Mohammad; Mahadeva, Suresha K.; Khondoker, Abu Hasan; Kim, Jaehwan

    2012-04-01

    This paper investigates the feasibility of conductometric glucose biosensor based on glucose oxidase (GOx) immobilized TiO2-cellulose hybrid nanocomposite. 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 (GOx) was immobilized into this hybrid material by physical adsorption method. The successful immobilization of GOx into TiO2-cellulose hybrid nanocomposite via covalent bonding between TiO2 and GOx was confirmed by X-ray photoelectron analysis. The linear response of our propose glucose biosensor is obtained in the range of 1-10mM with correlation coefficient of 0.93. Our study demonstrates TiO2-cellulose hybrid material as a potential candidate for an inexpensive, flexible and disposable glucose biosensor.

  1. 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.

  2. Pretreatment assisted synthesis and characterization of cellulose nanocrystals and cellulose nanofibers from absorbent cotton.

    Science.gov (United States)

    Abu-Danso, Emmanuel; Srivastava, Varsha; Sillanpää, Mika; Bhatnagar, Amit

    2017-03-30

    In this work, cellulose nanocrystals (CNCs) and cellulose nanofibers (CNFs) were synthesized from absorbent cotton. Two pretreatments viz. dewaxing and bleaching with mild alkali were applied to the precursor (cotton). Acid hydrolysis was conducted with H2SO4 and dissolution of cotton was achieved with a mixture of NaOH-thiourea-urea-H2O at -3°C. Synthesized cellulose samples were characterized using FTIR, XRD, SEM, BET, and zeta potential. It seems that synthesis conditions contributed to negative surface charge on cellulose samples and CNCs had the higher negative surface charge compared to CNFs. Furthermore, BET surface area, pore volume and pore diameter of CNCs were found to be higher as compared to CNFs. The dewaxed cellulose nanofibers (CNF D) had a slightly higher BET surface area (0.47m(2)/g) and bigger pore diameter (59.87Å) from attenuated contraction compared to waxed cellulose nanofibers (CNFW) (0.38m(2)/g and 44.89Å). The XRD of CNCs revealed a semi-crystalline structure and the dissolution agents influenced the crystallinity of CNFs. SEM images showed the porous nature of CNFs, the flaky nature and the nano-sized width of CNCs. Synthesized CNF D showed a better potential as an adsorbent with an average lead removal efficiency of 91.49% from aqueous solution.

  3. Coral bleaching independent of photosynthetic activity.

    Science.gov (United States)

    Tolleter, Dimitri; Seneca, François O; DeNofrio, Jan C; Krediet, Cory J; Palumbi, Stephen R; Pringle, John R; Grossman, Arthur R

    2013-09-23

    The global decline of reef-building corals is due in part to the loss of algal symbionts, or "bleaching," during the increasingly frequent periods of high seawater temperatures. During bleaching, endosymbiotic dinoflagellate algae (Symbiodinium spp.) either are lost from the animal tissue or lose their photosynthetic pigments, resulting in host mortality if the Symbiodinium populations fail to recover. The >1,000 studies of the causes of heat-induced bleaching have focused overwhelmingly on the consequences of damage to algal photosynthetic processes, and the prevailing model for bleaching invokes a light-dependent generation of toxic reactive oxygen species (ROS) by heat-damaged chloroplasts as the primary trigger. However, the precise mechanisms of bleaching remain unknown, and there is evidence for involvement of multiple cellular processes. In this study, we asked the simple question of whether bleaching can be triggered by heat in the dark, in the absence of photosynthetically derived ROS. We used both the sea anemone model system Aiptasia and several species of reef-building corals to demonstrate that symbiont loss can occur rapidly during heat stress in complete darkness. Furthermore, we observed damage to the photosynthetic apparatus under these conditions in both Aiptasia endosymbionts and cultured Symbiodinium. These results do not directly contradict the view that light-stimulated ROS production is important in bleaching, but they do show that there must be another pathway leading to bleaching. Elucidation of this pathway should help to clarify bleaching mechanisms under the more usual conditions of heat stress in the light.

  4. Influence of intermediary filling material on microleakage of intracoronally bleached and restored teeth

    Directory of Open Access Journals (Sweden)

    Maryam Khoroushi

    2009-01-01

    Full Text Available Background: Failure of composite restorations in terms of microleakage after intracoronal bleaching has been reported. The purpose of this study was to assess in vitro effect of sodium ascorbate and calcium hydroxide as intermediary filling materials to repair the microleakage associated with adhe-sive restoration following intracoronal bleaching. Methods: Sixty endodontically-treated incisors with access cavities extended to the cementoenamel junction in gingival margin were randomly divided into five equal groups. In group 1, cavities were restored by applying Single Bond and Z100 composite resin. In groups 2-5, 35% hydrogen peroxide gel was placed into the pulp chamber and sealed for 5 days. In group 2, teeth were then restored as in group 1. In groups 3 and 4, 10% sodium ascorbate gel and calcium hydroxide paste were applied in the pulp chamber for 40 hours, removed, rinsed and then, restored. In group 5, the cavities were incu-bated for 7 days and then, restored. Samples were thermocycled, immersed in basic fuschin, and sec-tioned. Dye penetration was scored using a stereomicroscope. Data were analyzed using Kruskal- Wallis and Mann-Whitney U tests (α = 0.05. Results: There was no significant difference in enamel margins (P = 0.163. In dentinal margins (P = 0.003, groups 1, 3 and 5 exhibited similar leakage patterns, each one of groups 1, 3 and 5 had sig-nificant differences with each one of groups 2 and 4. Conclusion: Intracoronal bleaching using 35% H2O2 gel increases the microleakage in dentinal margins. Application of the antioxidant agent or a seven-day delay following bleaching may improve the marginal integrity. Applying calcium hydroxide might jeopardize dentinal sealing.

  5. 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.

  6. INFLUENCE OF STEAM EXPLOSION ON THECRYSTALLINITY OF CELLULOSE FIBER

    OpenAIRE

    Jacquet, Nicolas; Vanderghem, Caroline; Danthine, Sabine; Blecker, Christophe; Richel, Aurore

    2014-01-01

    The aim of the present study is to compare the effect of different steam explosion treatments on crystallinity properties of a pure bleached cellulose. Steam explosion process is composed of two distinct stages: vapocracking and explosive decompression. The treatment intensities is determined by a severity factor, established by a correlation between temperature process and retention time. The results show that steam explosion treatment has an impact on the crystallinity properties of pure ce...

  7. 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%.

  8. Cellulose Insulation

    Science.gov (United States)

    1980-01-01

    Fire retardant cellulose insulation is produced by shredding old newspapers and treating them with a combination of chemicals. Insulating material is blown into walls and attics to form a fiber layer which blocks the flow of air. All-Weather Insulation's founders asked NASA/UK-TAP to help. They wanted to know what chemicals added to newspaper would produce an insulating material capable of meeting federal specifications. TAP researched the query and furnished extensive information. The information contributed to successful development of the product and helped launch a small business enterprise which is now growing rapidly.

  9. 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.

  10. Dental pulp stem cells

    DEFF Research Database (Denmark)

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

    2015-01-01

    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.......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...

  11. Effect of process parameters on the dryness of molded pulp products

    DEFF Research Database (Denmark)

    Didone, Mattia; Tosello, Guido

    2016-01-01

    Molded pulp products are made from cellulose fibers dispersed in water then formed, drained and dried. As in the conventional papermaking process, the most energ yintensive operation (including time) is drying. To gain a better understanding of the process parameters involved and to investigate...

  12. 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)

  13. Effect of temperature and bleaching agent on bleaching of liquid Cheddar whey.

    Science.gov (United States)

    Listiyani, M A D; Campbell, R E; Miracle, R E; Barbano, D M; Gerard, P D; Drake, M A

    2012-01-01

    The use of whey protein as an ingredient in foods and beverages is increasing, and thus demand for colorless and mild-tasting whey protein is rising. Bleaching is commonly applied to fluid colored cheese whey to decrease color, and different temperatures and bleach concentrations are used. The objectives of this study were to compare the effects of hot and cold bleaching, the point of bleaching (before or after fat separation), and bleaching agent on bleaching efficacy and volatile components of liquid colored and uncolored Cheddar whey. First, Cheddar whey was manufactured, pasteurized, fat-separated, and subjected to one of a number of hot (68°C) or cold (4°C) bleaching applications [hydrogen peroxide (HP) 50 to 500 mg/kg; benzoyl peroxide (BP) 25 to 100 mg/kg] followed by measurement of residual norbixin and color by reflectance. Bleaching agent concentrations were then selected for the second trial. Liquid colored Cheddar whey was manufactured in triplicate and pasteurized. Part of the whey was collected (no separation, NSE) and the rest was subjected to fat separation (FSE). The NSE and FSE wheys were then subdivided and bleaching treatments (BP 50 or 100 mg/kg and HP 250 or 500 mg/kg) at 68°C for 30 min or 4°C for 16 h were applied. Control NSE and FSE with no added bleach were also subjected to each time-temperature combination. Volatile compounds from wheys were evaluated by gas chromatography-mass spectrometry, and norbixin (annatto) was extracted and quantified to compare bleaching efficacy. Proximate analysis, including total solids, protein, and fat contents, was also conducted. Liquid whey subjected to hot bleaching at both concentrations of HP or at 100mg/kg BP had greater lipid oxidation products (aldehydes) compared with unbleached wheys, 50mg/kg BP hot-bleached whey, or cold-bleached wheys. No effect was detected between NSE and FSE liquid Cheddar whey on the relative abundance of volatile lipid oxidation products. Wheys bleached with BP had

  14. Short communication: The influence of solids concentration and bleaching agent on bleaching efficacy and flavor of sweet whey powder.

    Science.gov (United States)

    Jervis, M G; Smith, T J; Drake, M A

    2015-04-01

    Recent studies have demonstrated the effect of bleaching conditions and bleaching agent on flavor and functional properties of whey protein ingredients. Solids concentration at bleaching significantly affected bleaching efficacy and flavor effects of different bleaching agents. It is not known if these parameters influence quality of sweet whey powder (SWP). The purpose of this study was to determine the effects of solids concentration and bleaching agent on the flavor and bleaching efficacy of SWP. Colored cheddar whey was manufactured, fat separated, and pasteurized. Subsequently, the whey (6.7% solids) was bleached, concentrated using reverse osmosis (RO) to 14% solids, and then spray dried, or whey was concentrated before bleaching and then spray dried. Bleaching treatments included a control (no bleaching, 50 °C, 60 min), hydrogen peroxide (HP; 250 mg/kg, 50 °C, 60 min), benzoyl peroxide (50 mg/kg, 50 °C, 60 min), lactoperoxidase (20 mg/kg of HP, 50 °C, 30 min), and external peroxidase (MaxiBright, DSM Food Specialties, Delft, the Netherlands; 2 dairy bleaching units/mL, 50 °C, 30 min). The experiment was repeated in triplicate. Sensory properties and volatile compounds of SWP were evaluated by a trained panel and gas chromatography-mass spectrometry, respectively. Bleaching efficacy (norbixin destruction) and benzoic acid were measured by HPLC. Differences in bleaching efficacy, sensory and volatile compound profiles, and benzoic acid were observed with different bleaching agents, consistent with previous studies. Solids concentration affected bleaching efficacy of HP, but not other bleaching agents. The SWP from whey bleached with HP or lactoperoxidase following RO had increased cardboard and fatty flavors and higher concentrations of lipid oxidation compounds compared with SWP from whey bleached before RO. The SWP bleached with benzoyl peroxide after RO contained less benzoic acid than SWP from whey bleached before RO. These results indicate that

  15. Production of ethanol from cassava pulp via fermentation with a surface-engineered yeast strain displaying glucoamylase

    Energy Technology Data Exchange (ETDEWEB)

    Kosugi, Akihiko; Murata, Yoshinori; Arai, Takamitsu; Mori, Yutaka [Post-harvest Science and Technology Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686 (Japan); Kondo, Akihiko [Department of Chemical Science and Engineering, Faculty of Engineering, Kobe University, Nada-ku, Kobe, 657-8501 (Japan); Ueda, Mitsuyoshi [Department of Applied Biochemistry, Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan); Vaithanomsat, Pilanee; Thanapase, Warunee [Nanotechnology and Biotechnology Division, Kasetsart Agricultural and Agro-Industrial Product Improvement Institute (KAPI), Kasetsart University, 50 Chatuchak, Ladyao, Bangkok 10900 (Thailand)

    2009-05-15

    Cassava (Manihot esculenta Crantz) pulp, produced in large amounts as a by-product of starch manufacturing, is a major biomass resource in Southeast Asian countries. It contains abundant starch (approximately 60%) and cellulose fiber (approximately 20%). To effectively utilize the cassava pulp, an attempt was made to convert its components to ethanol using a sake-brewing yeast displaying glucoamylase on the cell surface. Saccharomyces cerevisiae Kyokai no. 7 (strain K7) displaying Rhizopus oryzae glucoamylase, designated strain K7G, was constructed using the C-terminal-half region of {alpha}-agglutinin. A sample of cassava pulp was pretreated with a hydrothermal reaction (140 C for 1 h), followed by treatment with a Trichoderma reesei cellulase to hydrolyze the cellulose in the sample. The K7G strain fermented starch and glucose in pretreated samples without addition of amylolytic enzymes, and produced ethanol in 91% and 80% of theoretical yield from 5% and 10% cassava pulp, respectively. (author)

  16. 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).

  17. 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.

  18. 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.

  19. Further Promote the Development of pulping Industry%积极发展制浆工业

    Institute of Scientific and Technical Information of China (English)

    杨懋暹

    2001-01-01

    本文主要论述了以下几个方面:(1)积极有效地建立速生丰产林;(2)企业规模要跟上时代的步伐;(3)支持超大型浆厂的技术进步;(4)开发了与环境保护协调发展的漂白技术;(5)大型浆厂的风险分析;(6)浆厂投产初期的风险分析。%This paper deals with the following aspects: (1)Building fastgrowing forest base effectively, (2)Pulp mill scale should keep pace with international trend, (3)The technical support for the giant pulp mill, (4)The environmentally friendly bleaching technology, (5) Risk analysis of large scale pulp mill, (6) Risk analysis in the early stage of production

  20. Quality of wood and pulp from a clone of Eucalyptus grandis planted at three locations

    Directory of Open Access Journals (Sweden)

    Cláudio Angeli Sansígolo

    Full Text Available Eucalyptus grandis is one of the most popular species to use as raw material for pulp production in Brazil, as it provides excellent pulping, bleaching and papermaking results. The main objective of this study is to examine the quality of wood and pulp from a clone of Eucalyptus grandis, at age 4 years approximately, planted in three different soils, two of which being low fertility and one being a superior fertility soil, and their reflections on wood quality and pulping results. Chemical analyses of the soils followed guidelines developed by Raij et al. (2001, while physical and chemical properties of the wood followed ABTCP, TAPPI and ABNT standards. Chemical analyses of the soils pointed to lower fertility in Fazenda Limeira and Fazenda Tapera Queimada as opposed to higher fertility in Fazenda Mendes União. Results revealed stronger tendencies for the stand grown in the less fertile soils (Fazenda Limeira and Fazenda Tapera Queimada in comparison to the stand grown in more fertile soil (Fazenda Mendes União as to: higher wood and bark basic density, lower height and dry matter content, higher bark content, lower extractives content and higher holocellulose content, higher total and screened yields from pulping, lower specific wood consumption/t of pulp, and higher tear and tensile indices at low refining levels.

  1. Effect of the chemical treatments on the characteristics of natural cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Sosiati, H., E-mail: hsosiati@ugm.ac.id [Nanomaterials Research Group, Integrated Research and Testing Laboratory (LPPT), Gadjah Mada University, Yogyakarta 55281 (Indonesia); Muhaimin, M.; Abdilah, P.; Wijayanti, D. A. [Department of Physics, Faculty of Mathematics and Natural of Sciences, Gadjah Mada University, Yogyakarta 55281 (Indonesia); Harsojo; Triyana, K. [Nanomaterials Research Group, Integrated Research and Testing Laboratory (LPPT), Gadjah Mada University, Yogyakarta 55281, Indonesia and Department of Physics, Faculty of Mathematics and Natural of Sciences, Gadjah Mada University, Yogyakarta 55281 (Indonesia)

    2014-09-25

    In order to characterize the morphology and size distribution of the cellulose fibers, natural cellulose from kenaf bast fibers was extracted using two chemical treatments; (1) alkali-bleaching-ultrasonic treatment and (2) alkali-bleaching-hydrolysis. Solutions of NaOH, H{sub 2}O{sub 2} and H{sub 2}SO{sub 4} were used for alkalization, bleaching and hydrolysis, respectively. The hydrolyzed fibers were centrifuged at a rotation speed of 10000 rpm for 10 min to separate the nanofibers from the microfibers. The separation was repeated in 7 steps by controlling pH of the solution in each step until neutrality was reached. Fourier transform infrared (FTIR) spectroscopy was performed on the fibers at the final step of each treatment: i.e. either ultrasonic treated- or hydrolyzed microfibers. Their FTIR spectra were compared with FTIR spectrum of a reference commercial α-cellulose. Changes in morphology and size distribution of the treated fibers were examined by scanning electron microscopy (SEM). FTIR spectra of ultrasonic treated- and hydrolyzed microfibers nearly coincided with the FTIR spectrum of commercial α-cellulose, suggesting successful extraction of cellulose. Ultrasonic treatment for 6 h resulted in a specific morphology in which cellulose nanofibers (≥100 nm) were distributed across the entire surface of cellulose microfibers (∼5 μm). Constant magnetic stirring combined with acid hydrolysis resulted in an inhomogeneous size distribution of both cellulose rods (500 nm-3 μm length, 100–200 nm diameter) and particles 100–200 nm in size. Changes in morphology of the cellulose fibers depended upon the stirring time; longer stirring time resulted in shorter fiber lengths.

  2. 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.

  3. 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

  4. Flexible biorefinery for producing fermentation sugars, lignin and pulp from corn stover.

    Science.gov (United States)

    Kadam, Kiran L; Chin, Chim Y; Brown, Lawrence W

    2008-05-01

    A new biorefining process is presented that embodies green processing and sustainable development. In the spirit of a true biorefinery, the objective is to convert agricultural residues and other biomass feedstocks into value-added products such as fuel ethanol, dissolving pulp, and lignin for resin production. The continuous biomass fractionation process yields a liquid stream rich in hemicellulosic sugars, a lignin-rich liquid stream, and a solid cellulose stream. This paper generally discusses potential applications of the three streams and specifically provides results on the evaluation of the cellulose stream from corn stover as a source of fermentation sugars and specialty pulp. Enzymatic hydrolysis of this relatively pure cellulose stream requires significantly lower enzyme loadings because of minimal enzyme deactivation from nonspecific binding to lignin. A correlation was shown to exist between lignin removal efficiency and enzymatic digestibility. The cellulose produced was also demonstrated to be a suitable replacement for hardwood pulp, especially in the top ply of a linerboard. Also, the relatively pure nature of the cellulose renders it suitable as raw material for making dissolving pulp. This pulping approach has significantly smaller environmental footprint compared to the industry-standard kraft process because no sulfur- or chlorine-containing compounds are used. Although this option needs some minimal post-processing, it produces a higher value commodity than ethanol and, unlike ethanol, does not need extensive processing such as hydrolysis or fermentation. Potential use of low-molecular weight lignin as a raw material for wood adhesive production is discussed as well as its use as cement and feed binder. As a baseline application the hemicellulosic sugars captured in the hydrolyzate liquor can be used to produce ethanol, but potential utilization of xylose for xylitol fermentation is also feasible. Markets and values of these applications are

  5. Nanocrystalline cellulose extracted from pine wood and corncob.

    Science.gov (United States)

    Ditzel, Fernanda I; Prestes, Eduardo; Carvalho, Benjamim M; Demiate, Ivo M; Pinheiro, Luís A

    2017-02-10

    The extraction of nanocrystalline cellulose from agro-residues is an interesting alternative to recover these materials. In the present study, nanocrystalline cellulose was extracted from pine wood and corncob. In addition, microcrystalline cellulose was used as a reference to compare results. Initially, the lignocellulosic residues were submitted to delignification pre-treatments. At the end of the process, the bleached fibre was submitted to acid hydrolysis. Additionally, microparticles were obtained from the spray-drying of the nanocrystalline cellulose suspensions. The nanocrystalline cellulose yield for the pine wood was 9.0-% of the value attained for the microcrystalline cellulose. For the corncob, the value was 23.5-%. Therefore, complementary studies are necessary to improve the yield. The spray-dried microparticles showed a crystallinity index of 67.8-% for the pine wood, 70.9-% for the corncob and 79.3-% for the microcrystalline cellulose. These microparticles have great potential for use in the production of polymer composites processed by extrusion.

  6. 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.

  7. 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.

  8. Wet Oxidation: A Promising Option for the Treatment of Pulp and Paper Mill Wastewater

    Science.gov (United States)

    Garg, A.

    2012-05-01

    Wet oxidation (WO) is used to degrade persistent organic or inorganic impurities present in industrial wastewater. The process utilizes severe oxidation conditions (i.e., high temperature and pressures) to achieve the efficient degradation of pollutants. To obtain high degradation at lower operation conditions, catalytic WO process is being suggested. The wastewater generated from a pulp and paper mill contains several recalcitrant compounds like lignin, hemi-cellulose, phenols, sulfides etc. Therefore, pulp and paper mill effluent have low biodegradability and are not amenable for conventional biological process. With the implementation of stringent regulations, pulp and paper mill operators need a cleaner disposal route for the wastewater. In this mini-review, the results obtained from the recently published studies on WO treatment for pulp and paper mill effluent are compiled and presented. Finally, the recommendations for the future work are also given.

  9. 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.

  10. 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.

  11. Coral bleaching: the role of the host.

    Science.gov (United States)

    Baird, Andrew H; Bhagooli, Ranjeet; Ralph, Peter J; Takahashi, Shunichi

    2009-01-01

    Coral bleaching caused by global warming is one of the major threats to coral reefs. Very recently, research has focused on the possibility of corals switching symbionts as a means of adjusting to accelerating increases in sea surface temperature. Although symbionts are clearly of fundamental importance, many aspects of coral bleaching cannot be readily explained by differences in symbionts among coral species. Here we outline several potential mechanisms by which the host might influence the bleaching response, and conclude that predicting the fate of corals in response to climate change requires both members of the symbiosis to be considered equally.

  12. The role of microorganisms in coral bleaching.

    Science.gov (United States)

    Rosenberg, Eugene; Kushmaro, Ariel; Kramarsky-Winter, Esti; Banin, Ehud; Yossi, Loya

    2009-02-01

    Coral bleaching is the disruption of the symbiosis between the coral host and its endosymbiotic algae. The prevalence and severity of the disease have been correlated with high seawater temperature. During the last decade, the major hypothesis to explain coral bleaching is that high water temperatures cause irreversible damage to the symbiotic algae resulting in loss of pigment and/or algae from the holobiont. Here, we discuss the evidence for an alternative but not mutually exclusive concept, the microbial hypothesis of coral bleaching.

  13. 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.

  14. 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.

  15. Cellulose metabolism in plants.

    Science.gov (United States)

    Hayashi, Takahisa; Yoshida, Kouki; Park, Yong Woo; Konishi, Teruko; Baba, Kei'ichi

    2005-01-01

    Many bacterial genomes contain a cellulose synthase operon together with a cellulase gene, indicating that cellulase is required for cellulose biosynthesis. In higher plants, there is evidence that cell growth is enhanced by the overexpression of cellulase and prevented by its suppression. Cellulase overexpression could modify cell walls not only by trimming off the paracrystalline sites of cellulose microfibrils, but also by releasing xyloglucan tethers between the microfibrils. Mutants for membrane-anchored cellulase (Korrigan) also show a typical phenotype of prevention of cellulose biosynthesis in tissues. All plant cellulases belong to family 9, which endohydrolyzes cellulose, but are not strong enough to cause the bulk degradation of cellulose microfibrils in a plant body. It is hypothesized that cellulase participates primarily in repairing or arranging cellulose microfibrils during cellulose biosynthesis in plants. A scheme for the roles of plant cellulose and cellulases is proposed.

  16. Pulp response to Streptococcus mutans.

    Science.gov (United States)

    Paterson, R C; Pountney, S K

    1987-09-01

    The maxillary molar pulps of germ-free rats were mechanically exposed, and suspensions of a strain of freshly grown Streptococcus mutans were applied to the pulp wounds. The pulps were left open to the oral environment, and the animals were maintained in the isolator until they were killed in groups after 2, 7, and 28 days. After 2 days there was little evidence of any pulp response. In the 7-day group early pulp necrosis was present. No evidence of inflammatory infiltration was detected in either the 2- or 7-day animals. After 28 days there was extensive pulp necrosis in many specimens. Dentine bridges were present in fewer than one fourth of the teeth.

  17. 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.

  18. 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 (pperoxide passage than did GD and GE (pperoxide placed into the pulp chamber passed through the dental hard tissues, reaching the external surface and the periodontal tissue. The cementum surface

  19. A comparative study on properties of micro and nanopapers produced from cellulose and cellulose nanofibres.

    Science.gov (United States)

    Mtibe, A; Linganiso, Linda Z; Mathew, Aji P; Oksman, K; John, Maya J; Anandjiwala, Rajesh D

    2015-03-15

    Cellulose nanocrystals (CNCs) and cellulose nanofibres (CNFs) were successfully extracted from cellulose obtained from maize stalk residues. A variety of techniques, such as Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA) were used for characterization and the experimental results showed that lignin and hemicellulose were removed to a greater extent by following the chemical methods. Atomic force microscopy (AFM) results confirmed that the diameters of CNCs and CNFs were ranging from 3 to 7 nm and 4 to 10nm, respectively, with their lengths in micro scale. CNCs suspension showed a flow of birefringence, however, the same was not observed in the case of suspension containing CNFs. XRD analysis confirmed that CNCs had high crystallinity index in comparison to cellulose and CNFs. Nanopapers were prepared from CNCs and CNFs by solvent evaporation method. Micropapers were also prepared from cellulose pulp by the same technique. Nanopapers made from CNFs showed less transparency as compared to nanopapers produced from CNCs whereas high transparency as compared to micropaper. Nanopapers produced from CNFs provided superior mechanical properties as compared to both micropaper and nanopapers produced from CNCs. Also, nanopapers produced from CNFs were thermally more stable as compared to nanopapers produced from CNCs but thermally less stable as compared to micropapers.

  20. SPECIFIC INTERACTION ACTING AT A CELLULOSE-BINDING DOMAIN/CELLULOSE INTERFACE FOR PAPERMAKING APPLICATION

    Directory of Open Access Journals (Sweden)

    Shingo Yokota

    2008-11-01

    Full Text Available Specific and strong cellulose-binding characteristics were utilized for promoting retention of additives in contaminated papermaking systems. Cellulose-binding domain (CBD of cellulase derived from Trichoderma viride was separated by digestion with papain, and then introduced into anionic polyacrylamide (A-PAM through a condensation reaction using water-soluble carbodiimide. The CBD-modified A-PAM (CBD-A-PAM showed good retention on pulp fibers, resulting in high tensile strength paper sheets. The effect remained almost unchanged in the presence of model interfering substances such as ligninsulfonate and Ca2+ ions, whereas commercial cationic paper-strengthening polymer became ineffective. The cellulose-binding force of CBD was quantitatively determined by atomic force microscopy (AFM in the liquid state. Histidine-tagged CBD protein was obtained using Escherichia coli via an expression of CBD derived from Cellulomonas fimi, and immobilized on a gold-coated AFM probe. A strong attractive force was detected only at a CBD/cellulose interface, even when Ca2+ ions were present in high concentration. Direct estimation of CBD affinity for cellulose substrate by AFM would provide significant information on the interfacial interactions useful for the functional design of papermaking additives.

  1. Characterization and evaluation of golpata fronds as pulping raw materials.

    Science.gov (United States)

    Jahan, M Sarwar; Chowdhury, D A Nasima; Islam, M Khalidul

    2006-02-01

    The chemical, morphological and anatomical studies of golpata fronds have been discussed. The lignin, pentosan and alpha-cellulose in golpata fronds were comparable to some common nonwood and hardwood raw materials. The alkali, water and dichloromethane solubility were higher than wood and common nonwood. The fiber length 1.73 mm was observed, which is little bit shorter than softwood and longer than hardwood but fiber diameter was very short. The pulpability of golpata fronds has also been studied. The pulp yield was very low and Kappa number was high. The strength properties were better than that of some common nonwood pulps. FT-IR spectrum and alkaline nitrobenzene oxidation products showed that golpata fronds lignin mainly consist of syringyl (S) and guaiacyl units (V).

  2. 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.

  3. 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.

  4. 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

  5. An extracellular thermo-alkali-stable laccase from Bacillus tequilensis SN4, with a potential to biobleach softwood pulp

    OpenAIRE

    Sondhi, Sonica; Sharma, Prince; George, Nancy; Chauhan, Prakram Singh; Puri, Neena; Gupta, Naveen

    2014-01-01

    Degradation of residual lignin in kraft pulp by chemical bleaching is implicated in causing environmental pollution. The use of thermo- and alkali-tolerant bacterial laccases is considered to be important biological alternative to chemical processing. Laccases from Bacillus species have shown promise in this respect but their intracellular/spore bound presence make their industrial application economically unfeasible. We report here on a novel extracellular active thermo-alkali-stable laccase...

  6. 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

  7. Photochromic paper from wood pulp modification via layer-by-layer assembly of pulp fiber/chitosan/spiropyran.

    Science.gov (United States)

    Tian, Xiaojun; Wang, Bin; Li, Jinpeng; Zeng, Jinsong; Chen, Kefu

    2017-02-10

    Cellulosic fiber introducing with photochromic properties can be used in many fields such as security packaging, printing paper, and rewritable paper. To introduce photochromic property to individual fiber, a polyelectrolyte composite layer composed of cationic chitosan (CS) and anionic carboxyl-containing spiropyran (SPCOOH) on pulp fibers was designed using layer-by-layer assembly technique. Scanning electron microscope observation showed that the SPCOOH was successfully absorbed onto the surface of fiber. The photochromic characteristic of LbL-treated fiber could be triggered by UV-vis absorption spectrum and the LbL-treated fibers had a good compatibility with pulp fibers. This study gives a highly effective method to impart the photochromic characteristic to paper.

  8. 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

  9. USE CELLULOSE FOR CLEANING CONCENTRATED SUGAR SOLUTIONS

    Directory of Open Access Journals (Sweden)

    N. G. Kul’neva

    2015-01-01

    Full Text Available Summary. Producing high quality intermediate products in the boiling-crystallization station is an actual problem of sugar production. In the production of white sugar brown sugar syrup is not further purified that decreases the quality of the end product. Studies have been conducted using cellulose as an adsorbent for the purification of concentrated sugar solutions, having affinity to dyes and other impurities. Research have been carried out with the intermediate products of the Lebedyan sugar plant. Test results have shown cellulose ability to adsorb the dyes in sugar production. The influence of the adsorbent concentration and the mass fraction of solids in the syrup on the decolorization effect has been studied; rational process parameters have been obtained. It has been found that proceeding an additional adsorption purification of brown sugars syrup allows to reduce the solution color, increase the amount and quality of the end product. Adsorbing means, received from production wastes on the basis of organic resources, have many advantages: economical, environmentally friendly for disposal, safe to use, reliable and efficient in use. Conducted research on using cellulose as adsorbent for treatment of concentrated sugar solutions, having an affinity for colouring matter and other impurities. The experiments were carried out on the intermediates Lebedyanskiy sugar factory. The test results showed the ability of cellulose to adsorb coloring matter of sugar production. To evaluate the effect of bleaching depending on the mass fraction of dry substances prepared yellow juice filtration of sugar concentration of 55, 60, 65 % with subsequent adsorption purification of cellulose. The results of the experiment built adsorption isotherm of dyestuffs. The influence of the concentration of the adsorbent and a mass fraction of solids of juice filtration on the efficiency of decolorization obtained by rational parameters of the process. It is

  10. Pulp-mill related polychlorinated organic compounds in Baltic Sea sediments

    Energy Technology Data Exchange (ETDEWEB)

    Jonsson, Per (Swedish Environmental Protection Agency, Solna (Sweden)); Rappe, C.; Kjeller, L.O. (Umeaa Univ. (Sweden). Inst. of Environmental Chemistry); Kierkegaard, A. (Stockholm Univ. (Sweden). Inst. of Applied Environmental Research); Haakansson, L. (Uppsala Univ. (Sweden). Inst. of Earth Sciences); Jonsson, Bjoern (County Adm. Board, Umeaa (Sweden))

    1993-01-01

    Sediment samples from the Baltic basin were analyzed for PCDD/Fs, alkyl-CDFs, chloroguaiacols and EOCl. The EOCl distribution pattern in the Iggesund pulp-mill area shows high sediment concentrations close to the mill, and decreasing concentrations with increasing distance from the mill. Two series of alkyl-CDFs have been identified. The PCDD/Fs in offshore surficial sediments from the Baltic proper show a typical incineration pattern, while sediments collected in the vicinity of the mill show enhanced levels of 2,3,7,8-tetraCDD, 2,3,7,8- and 1,2,7,8-tetraCDF, and 1,2,3,7,8-pentaCDD. These PCDD/F congeners are statistically correlated to di-, tri-, and tetrachloroguaiacols, alkyl-CDFs, EOCl, and to the distance from the pulp mill, indicating the same source and transportation regime. Principal component analysis of the data set supports this conclusion. The three 2,3,7,8-tetrachloro-substituted PCDD/F congeners have formerly been found in high concentrations in sediments and crab hepatopancreas close to a pulp mill on the Swedish west coast. Our results from a pulp mill on the Swedish east coast support the conclusion that these congeners are typically associated with pulp bleaching. Deep layer sediments have significantly lower levels of PCDD/Fs. The isomer profiles are different in the surficial and the deep sediments, indicating a more natural preindustrial production of PCDD/Fs. (53 refs., 7 figs.).

  11. 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.

  12. Method of composite fluffing technology and its effect on properties of fluff pulp fiber%复合绒毛化及其对绒毛浆性能的影响

    Institute of Scientific and Technical Information of China (English)

    徐永建; 闫瑛; 岳小鹏; 张鼎军; 朱振峰

    2013-01-01

    以硫酸盐马尾松浆为原料,通过对比两种复合绒毛化方法对绒毛浆性能的影响得到,先对原浆纤维进行漂白,漂白接近终点时补加碱进行短时间的浓碱处理为较优的复合绒毛化方法,并通过进一步实验验证了该方法中进行短时间浓碱处理的合理性.结果表明,原浆纤维经复合绒毛化后,纸浆白度为76.66% ISO ,提高了52.77%,绒毛浆板耐破指数为0.57 kpa・m2/g ,下降了48.18%,绒毛浆吸收时间为8.42 s ,缩短了46.64%,吸收性为8.95 g/g ,干蓬松度为17.19 cm3/g ,这两个性能指标分别降低了10.23%,6.63%.%Composite fluffing technology of cellulose fiber in the process of fluff pulp making was researched using pinus massoniana lamb as the raw material .Effects on fluff pulp prop-erties of two composite fluffing technologies were compared .It indicated that bleaching the virgin fiber initially and then treating it with enormous alkali towards the end of bleaching was the more preferable method .It also revealed that when fiber was treated by this method , brightness of it was 76 .13% ISO and increased 51 .71% ,burst index was 0 .57 kpa・m2/g and decreased 48 .18% ,the absorption time was 8 .42 s and decreased 46 .64% in comparison with virgin fiber .Meanwhile ,absorption and dry bulkiness of the fiber decreased 10 .23% , 6 .63% ,respectively .In addition ,rationality of the more preferable method for its effects on fiber properties was also researched .

  13. 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.

  14. 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 .

  15. ALKALINE PULP OF CORN STALKS

    Institute of Scientific and Technical Information of China (English)

    M.SarwarJalaan; M.AN.Russell; S.A.N.Shamim; A.I.Mostafa; Md.AbdulQuaiyyum

    2004-01-01

    Pulping of corn stalks was studied in soda,soda-anthraquinone (AQ), kraft and kraft-AQprocesses. The time, temperature and alkaliconcentration were varied in soda process. In respectto kappa number and pulp yield, 1 hour cooking at1400C in 14% alkali were best conditions for cornstalks pulping. Pulp yield was increased by 5.5% andkappa number was reduced by 4.4 points with anaddition of 0.05% AQ in the soda liquor. Breakinglength was better in soda-AQ process than sodaprocess but tear strength was inferior. In the kraftprocess, pulp yield was increased with increasingsulphidity and decreasing active alkali. Theeffectiveness of AQ in the low and high sulphiditykraft process was studied. Results showed that AQwas more effective in low sulphidity than highsulphidity. Strength properties in kraft processeswere better than the soda and soda-AQ processes.

  16. 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

  17. 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.

  18. 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.

  19. Properties of foam and composite materials made o starch and cellulose fiber

    Science.gov (United States)

    Composite materials were made of starch and cellulose fibers. Pre-gelatinized starch was effective in dispersing pulp fiber in a starch matrix to form a viscous starch/fiber dough. The starch/fiber dough was a useful feedstock for various composite foam and plastic materials. Viscous blends of star...

  20. PULP FIBER SIZE CHARACTERIZATION

    Institute of Scientific and Technical Information of China (English)

    Shijie Liu

    2004-01-01

    Pulp fiber length distribution characterization has been examined in this study. Because of the fiber morphology: slender in shape, fiber size distribution characterization is a very difficult task. Traditional technique involves separation of the particles by size,such as Bauer-McNett fiber classifier, and measuring the weight fractions. The particle fractions obtained may or may not reflect the desired size classification.On the other hand, the more recent technique through optical measurement of fiber length is limited by its inability to measure the mass of the particle fractions.Therefore, not only the two techniques fail to generate identical results, either one was accepted to be of better value. Pure hardwood kraft, softwood kraft, and their mixture samples have been measured for their fiber length distributions using an optical fiber quality analyzer: FQA. The data obtained from FQA are extensively studied to investigate more reliable way of representing the fiber length data and thus examining the viable route for measuring the fiber size distributions. It has been found that the fiber length averaged length 11 is a viable indicator of the average pulp fiber length. The fiber size fraction and/or distribution can be represented by the fiber "length" fractions.

  1. PULP FIBER SIZE CHARACTERIZATION

    Institute of Scientific and Technical Information of China (English)

    ShijieLiu

    2004-01-01

    Pulp fiber length distribution characterization hasbeen examined in this study. Because of the fibermorphology: slender in shape, fiber size distributioncharacterization is a very difficult task. Traditionaltechnique involves separation of the particles by size,such as Bauer-McNett fiber classifier, and measuringthe weight fractions. Themay or may not reflect theparticle fractions obtaineddesired size classification.On the other hand, the more recent technique throughoptical measurement of fiber length is limited by itsinability to measure the mass of the particle fractions.Therefore, not only the two techniques fail togenerate identical results, either one was accepted tobe of better value. Pure hardwood kraft, softwoodkraft, and their mixture samples have been measuredfor their fiber length distributions using an opticalfiber quality analyzer: FQA. The data obtained fromFQA are extensively studied to investigate morereliable way of representing the fiber length data andthus examining the viable route for measuring thefiber size distributions. It has been found that thefiber length averaged length 1~ is a viable indicator ofthe average pulp fiber length. The fiber size fractionand/or distribution can be represented by the fiber"length" fractions.

  2. 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.

  3. 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.

  4. Deflocculation of Cellulosic Suspensions with Anionic High Molecular Weight Polyelectrolytes

    Directory of Open Access Journals (Sweden)

    Markus Heikki Juhani Korhonen

    2014-04-01

    Full Text Available Pulp fibers have a strong tendency to form flocs in water suspensions, which may cause their undesirable distribution in the paper sheets. This flocculation can be controlled by adding, e.g., an anionic high molecular weight polyelectrolyte in the fiber suspension. The objective of this study was to investigate the effect of anionic polyelectrolytes on deflocculation kinetics, dewatering, and rheology of cellulosic suspensions. The results showed that both microfibrillated cellulose (MFC and macroscopic pulp fibers can be dispersed using anionic polyacrylamides (APAM. The higher the molecular weight of APAM, the higher is its effect. Adsorption experiments illustrate that anionic polyelectrolytes do not strongly attach to cellulose surfaces but they can be partly entrapped or can disperse nanocellulose fibrils (increase the swelling. Based on rheological experiments, the MFC network became weaker with APAM addition. Similar to the flocculation mechanism of cellulosic materials with polymers, deflocculation is also time dependent. Deflocculation occurs very rapidly, and the maximum deflocculation level is achieved within a few seconds. When mixing is continued, the floc size starts to increase again. Also dewatering was found to be strongly dependent on the contact time with the APAMs. These results indicate that the positive effects of anionic deflocculants are quickly diminished due to shear forces, and therefore, the best deflocculating effect is achieved using as short a contact time as possible.

  5. IMIDAZOLIUM IONIC LIQUIDS AS DISSOLVING SOLVENTS FOR CHEMICAL-GRADE CELLULOSE IN THE DETERMINATION OF FATTY ACIDS USING GAS CHROMATOGRAPHY-MASS SPECTROMETRY

    Directory of Open Access Journals (Sweden)

    Kessy F. Kilulya

    2011-06-01

    Full Text Available A quick, simple, and environmentally friendly sample preparation method for fatty acids analysis from chemical-grade cellulose was developed employing imidazolium based ionic liquids as solvents. A variety of imidazolium based ionic liquids were screened for their ability to dissolve chemical cellulose at different temperatures. Dissolution of chemical cellulose was observed to be dependent on the ionic liquids’ anions as well as temperature. The effect of ionic liquids on chemical cellulose was examined using FT-IR and TGA techniques, which showed no difference between the original and the regenerated cellulose except for the percentage mass residues in TGA profile which was high for regenerated cellulose, 15% compared to 8% of the original at 600 °C. Fatty acids extracted from cellulose were found to be predominant in the samples from different bleaching stages, with high levels in the oxygen delignification and low levels were observed in hypochlorite bleached samples. The number and levels of the identified fatty acids were observed to decrease with the bleaching sequence. The recoveries obtained using this method ranged from 90 to 107%.

  6. Local stressors reduce coral resilience to bleaching.

    Science.gov (United States)

    Carilli, Jessica E; Norris, Richard D; Black, Bryan A; Walsh, Sheila M; McField, Melanie

    2009-07-22

    Coral bleaching, during which corals lose their symbiotic dinoflagellates, typically corresponds with periods of intense heat stress, and appears to be increasing in frequency and geographic extent as the climate warms. A fundamental question in coral reef ecology is whether chronic local stress reduces coral resistance and resilience from episodic stress such as bleaching, or alternatively promotes acclimatization, potentially increasing resistance and resilience. Here we show that following a major bleaching event, Montastraea faveolata coral growth rates at sites with higher local anthropogenic stressors remained suppressed for at least 8 years, while coral growth rates at sites with lower stress recovered in 2-3 years. Instead of promoting acclimatization, our data indicate that background stress reduces coral fitness and resilience to episodic events. We also suggest that reducing chronic stress through local coral reef management efforts may increase coral resilience to global climate change.

  7. 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 on tidal flats due to the mixing caused by currents and waves. We apply bed level data to evaluate the amount of vertical sediment reworking in modern tidal channels and at a tidal flat. Cycles of deposition and erosion are measured with a bed level sensor, and the results show that gross sedimentation...... on the quantitative measures of sediment reworking, we suggest that repeated depositional and erosional cycles allow for complete bleaching of the tidal flat sediment, and we infer that quartz OSL dating can provide accurate ages for shallow tidal channel fill....

  8. 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.

  9. Effects of orthodontic forces on pulp tissue

    Directory of Open Access Journals (Sweden)

    Pinandi Sri Pudyani

    2006-09-01

    Full Text Available Numerous researches on pulp tissue changes caused by orthodontic forces have been performed, among others are: pulp angiogenesis, pulp tissue respiration rate, alkaline phosphatase and aspartate aminotransferase enzyme activities; micro vascular response inside the pulp and the effect of dental movement i.e. extrusion, intrusion, and torque. The result is still controversial, as some researchers claim that orthodontic force has a negative effect, others deny by saying there is no such effect on pulp tissue.

  10. 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....

  11. 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...

  12. Stability improvement in bleached phase holograms

    Science.gov (United States)

    Kumar, S.; Singh, K.

    1991-08-01

    An experimental study has been made of the influence of developer composition on the stability against the print-out effect of bleached, photographically recorded two-beam interference grating on Agfa-Gevaert 10E75 NAH plates. The diffraction efficiency has been increased by using potassium iodide and an iodine bleach process that converts a silver image into a dielectric image. An improvement in stability against the print-out effect has been observed by using two new developer compositions. Variation of the maximum diffraction efficiency against exposure to white light is shown graphically.

  13. 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.

  14. Identifying well-bleached quartz using the different bleaching rates of quartz and feldspar luminescence signals

    DEFF Research Database (Denmark)

    Murray, A.S.; Thomsen, Kristina Jørkov; Masuda, N.;

    2012-01-01

    When dating older sedimentary deposits using quartz, there are no unambiguous methods for identifying the presence of incomplete bleaching. Current statistical analysis of dose distributions depends entirely on the assumption that incomplete bleaching and mixing are the main causes of any excess...... in relative bleaching rates of quartz optically stimulated luminescence (OSL) and feldspar luminescence stimulated at 50 °C by infrared light (IR50) and feldspar luminescence stimulated at 290 °C by infrared light after a stimulation at 50 °C (pIRIR290), and use recently deposited samples to determine...... that the large aliquot data are more likely to be correct. We conclude that a comparison of quartz and feldspar doses provides a useful independent method for identifying well-bleached quartz samples, and that it is unwise to apply statistical models to dose distributions without clear evidence for the physical...

  15. Power generation and export: a new strategy for the survival of the Kamloops pulp mill

    OpenAIRE

    Ryan, Anthony John

    2006-01-01

    This paper presents a new strategy for survival of the Kamloops Cellulose Fibers softwood pulp mill. The mill currently competes exclusively in the North American softwood segment of the global kraft market, and is not generating returns sufficient to cover the cost of capital. The mill?s boilers need replacing or rebuilding in five years and the mill faces a more stringent environmental permit. Pressures on production costs make it increasingly difficult to continue operating profitably. By ...

  16. Bleaching of the discolored traumatized tooth

    DEFF Research Database (Denmark)

    Dahl, Jon E.; Kopperud, Siemen E.; Pallesen, Ulla

    2017-01-01

    This chapter focuses on the treatment of discolored traumatized teeth, most of them being non-vital and subsequently, endodontically treated. Tooth bleaching based upon hydrogen peroxide as the active agent, applied directly or produced in a chemical reaction from sodium perborate or carbamide pe...... retreatment....

  17. REMINERALIZATION POTENTIAL OF A CARBAMIDE BLEACHING AGENT

    Directory of Open Access Journals (Sweden)

    Marinova-Takorova Borislavova 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.

  18. Global warming and recurrent mass bleaching of corals

    Science.gov (United States)

    Hughes, Terry P.; Kerry, James T.; Álvarez-Noriega, Mariana; Álvarez-Romero, Jorge G.; Anderson, Kristen D.; Baird, Andrew H.; Babcock, Russell C.; Beger, Maria; Bellwood, David R.; Berkelmans, Ray; Bridge, Tom C.; Butler, Ian R.; Byrne, Maria; Cantin, Neal E.; Comeau, Steeve; Connolly, Sean R.; Cumming, Graeme S.; Dalton, Steven J.; Diaz-Pulido, Guillermo; Eakin, C. Mark; Figueira, Will F.; Gilmour, James P.; Harrison, Hugo B.; Heron, Scott F.; Hoey, Andrew S.; Hobbs, Jean-Paul A.; Hoogenboom, Mia O.; Kennedy, Emma V.; Kuo, Chao-Yang; Lough, Janice M.; Lowe, Ryan J.; Liu, Gang; McCulloch, Malcolm T.; Malcolm, Hamish A.; McWilliam, Michael J.; Pandolfi, John M.; Pears, Rachel J.; Pratchett, Morgan S.; Schoepf, Verena; Simpson, Tristan; Skirving, William J.; Sommer, Brigitte; Torda, Gergely; Wachenfeld, David R.; Willis, Bette L.; Wilson, Shaun K.

    2017-03-01

    During 2015–2016, record temperatures triggered a pan-tropical episode of coral bleaching, the third global-scale event since mass bleaching was first documented in the 1980s. Here we examine how and why the severity of recurrent major bleaching events has varied at multiple scales, using aerial and underwater surveys of Australian reefs combined with satellite-derived sea surface temperatures. The distinctive geographic footprints of recurrent bleaching on the Great Barrier Reef in 1998, 2002 and 2016 were determined by the spatial pattern of sea temperatures in each year. Water quality and fishing pressure had minimal effect on the unprecedented bleaching in 2016, suggesting that local protection of reefs affords little or no resistance to extreme heat. Similarly, past exposure to bleaching in 1998 and 2002 did not lessen the severity of bleaching in 2016. Consequently, immediate global action to curb future warming is essential to secure a future for coral reefs.

  19. 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.

  20. Dielectric Properties of Paper Made from Pulps Loaded with Ferroelectric Particles

    Directory of Open Access Journals (Sweden)

    Hind El Omari

    2016-01-01

    Full Text Available Due to its physical properties and its ease of manufacture, paper is widely used in various engineering applications such as electrical insulation materials for components in high voltage technology. In this study, paper loaded with ferroelectric nanoparticles (BaTiO3 and SrTiO3 was made with fibers obtained from plants growing on the Moroccan soil [Halfa (Stipa tenacissima, Agave (Agave americana, Pennisetum (Pennisetum alopecuroides, Typha (Typha latifolia, and Junc (Juncus effusus] and two commercial pulps (bleached softwood Kraft and newsprint grade thermomechanical pulps. A retention aid, cation polyacrylamide (Percol 292, was necessary to retain ferroelectric particles in the fibrous network and improve the dispersion of strontium titanate particles. The different pulp and handsheets used were characterized according to standard methods (Pulp and Paper Technical Association of Canada, PAPTAC. It is well known that annual and perennial plants contain high percentages of fines (length < 0.2 mm and short fibers. The results show that there is a strong interdependence between the dielectric properties of the loaded paper and surface finish, porosity, dispersion level of ceramic particles, fines content, shape, conformability, and sheet formation. The single dielectric relaxation detected towards low frequencies is attributed to hydroxyl groups present on fiber surfaces, in ceramic particles and adsorbed water.

  1. Construction materials as a waste management solution for cellulose sludge.

    Science.gov (United States)

    Modolo, R; Ferreira, V M; Machado, L M; Rodrigues, M; Coelho, I

    2011-02-01

    Sustainable waste management system for effluents treatment sludge has been a pressing issue for pulp and paper sector. Recycling is always recommended in terms of environmental sustainability. Following an approach of waste valorisation, this work aims to demonstrate the technical viability of producing fiber-cement roof sheets incorporating cellulose primary sludge generated on paper and pulp mills. From the results obtained with preliminary studies it was possible to verify the possibility of producing fiber-cement sheets by replacing 25% of the conventional used virgin long fiber by primary effluent treatment cellulose sludge. This amount of incorporation was tested on an industrial scale. Environmental parameters related to water and waste, as well as tests for checking the quality of the final product was performed. These control parameters involved total solids in suspension, dissolved salts, chlorides, sulphates, COD, metals content. In the product, parameters like moisture, density and strength were controlled. The results showed that it is possible to replace the virgin long fibers pulp by primary sludge without impacts in final product characteristics and on the environment. This work ensures the elimination of significant waste amounts, which are nowadays sent to landfill, as well as reduces costs associated with the standard raw materials use in the fiber-cement industrial sector.

  2. INFLUENCE OF STEAM EXPLOSION ON CRYSTALLINITY PROPERTIES OF PURE CELLULOSE FIBER

    OpenAIRE

    Jacquet, Nicolas; Vanderghem, Caroline; Danthine, Sabine; Blecker, Christophe; Paquot, Michel

    2012-01-01

    The aim of the present study is to compare the effect of different steam explosion treatments on crystallinity properties of a pure bleached cellulose. Steam explosion process is composed of two distinct stages: vapocracking and explosive decompression. The treatment intensities is determined by a severity factor, established by a correlation between temperature process and retention time. The results show that steam explosion treatment has an impact on the crystallinity properties of pure ce...

  3. 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.

  4. 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

  5. Cellulose binding domain proteins

    Science.gov (United States)

    Shoseyov, Oded; Shpiegl, Itai; Goldstein, Marc; Doi, Roy

    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.

  6. Cellulose Degradation by Cellulose-Clearing and Non-Cellulose-Clearing Brown-Rot Fungi

    OpenAIRE

    Highley, Terry L.

    1980-01-01

    Cellulose degradation by four cellulose-clearing brown-rot fungi in the Coniophoraceae—Coniophora prasinoides, C. puteana, Leucogyrophana arizonica, and L. olivascens—is compared with that of a non-cellulose-clearing brown-rot fungus, Poria placenta. The cellulose- and the non-cellulose-clearing brown-rot fungi apparently employ similar mechanisms to depolymerize cellulose; most likely a nonenzymatic mechanism is involved.

  7. 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

  8. 桉木浆轻ECF漂白%Improved Technology for Light Bleaching of Eucalyptus Pulp

    Institute of Scientific and Technical Information of China (English)

    Vera Sacon

    2008-01-01

    VCP是巴西的一家公司,生产各种桉木商品浆和纸产品.VCP采用轻ECF漂白技术,采用较低ClO2用量、氧化合物(H2O2、O2和O3)、苛性钠和热酸的最佳组合进行漂白.热酸段和O3段组合是生产超轻ECF漂白浆的关键.采用含元素氯的漂白程序O(CD)EopD生产的漂白浆,其有机氯化物(OCl)含量为300 g/t(风干浆).按规定,标准ECF漂白浆中OCl的含量是200 g/t.VCP在其Jacareí工厂有B和C2条生产线.C生产线采用Oa(Ze)DP漂白程序生产轻ECF漂白浆,其OCl含量为80g/t.B生产线采用OAZDP漂白程序生产超轻ECF漂白浆,其OCl含量低于30 g/t.VCP的2条漂白浆生产线废水量大约为8 m3/t.ECF、轻ECF和超轻ECF漂白浆机械强度之间没有明显的差异.

  9. 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%。

  10. Effects of TEMPO/NaBr/NaClO-oxidation of Nanocrystalline Cellulose on Its Properties%TEMPO/NaBr/NaClO氧化对纳米微晶纤维素性能的影响

    Institute of Scientific and Technical Information of China (English)

    姚文润; 徐清华; 靳丽强; 程正亮; 高扬

    2015-01-01

    Nanocrystalline cellulose ( NCC ) prepared by the acid-extraction of bleached hardwood kraft pulp ( BHKP ) , was oxidized by using TEMPO/NaBr/NaClO at pH 10 to prepare TEMPO-oxidized NCC ( TONCC) . The properties of NCC before and after oxidation were characterized by conductimetric titration, X-ray diffraction (XRD), and atomic force microscopy (AFM). The resulting product was then applied in the deinked pulp, and its improvement in pulp strength was evaluated. It was found that TONCC maintained the crystalline form of cellulose I, and showed better dispersibility, smaller dimension and higher level of carboxyl content compared with NCC. With the addition of NCC and TONCC to the deinked pulp respectively, the tearing and tensile indexes increased while they were compared with that of the control. When the addition of NCC and TONCC was 0. 6%, the tensile indexes were increased by 8. 7% and 14. 2%, respectively. When NCC and TONCC samples were applied together with cationic polyacrylamide (CPAM), tensile indexes of the deinked pulp were increased by 19. 6% and 27. 7%, respectively, in comparison with that of the control.%利用TEMPO/NaBr/NaClO体系对硫酸水解漂白硫酸盐浆制备的纳米微晶纤维素( NCC)进行改性制备氧化NCC ( TONCC)。采用电导滴定、X射线衍射( XRD)及原子力显微镜( AFM)对改性前后纳米微晶纤维素的表面性能及形貌进行表征,并将其作为造纸增强剂应用于废新闻纸脱墨浆,研究其对浆料强度性能的改善作用。结果表明,TONCC表面引入大量的羧基(0.806 mmol/g),而NCC表面羧基含量仅为0.02 mmol/g,外观由半透明变为透明。 TONCC保持了纤维素I的晶型结构,分散性能得到改善,宽度略有减小。将改性前后的纳米微晶纤维素加入到废新闻纸脱墨浆中,与对照样相比,当NCC和TONCC用量为0.6%时,浆料的抗张指数分别提高了8.7%和14.2%;NCC和TONCC用量为0.8%时,撕裂指数提高了约12%。将NCC和TONCC与CPAM

  11. Incorporating adaptive responses into future projections of coral bleaching.

    Science.gov (United States)

    Logan, Cheryl A; Dunne, John P; Eakin, C Mark; Donner, Simon D

    2014-01-01

    Climate warming threatens to increase mass coral bleaching events, and several studies have projected the demise of tropical coral reefs this century. However, recent evidence indicates corals may be able to respond to thermal stress though adaptive processes (e.g., genetic adaptation, acclimatization, and symbiont shuffling). How these mechanisms might influence warming-induced bleaching remains largely unknown. This study compared how different adaptive processes could affect coral bleaching projections. We used the latest bias-corrected global sea surface temperature (SST) output from the NOAA/GFDL Earth System Model 2 (ESM2M) for the preindustrial period through 2100 to project coral bleaching trajectories. Initial results showed that, in the absence of adaptive processes, application of a preindustrial climatology to the NOAA Coral Reef Watch bleaching prediction method overpredicts the present-day bleaching frequency. This suggests that corals may have already responded adaptively to some warming over the industrial period. We then modified the prediction method so that the bleaching threshold either permanently increased in response to thermal history (e.g., simulating directional genetic selection) or temporarily increased for 2-10 years in response to a bleaching event (e.g., simulating symbiont shuffling). A bleaching threshold that changes relative to the preceding 60 years of thermal history reduced the frequency of mass bleaching events by 20-80% compared with the 'no adaptive response' prediction model by 2100, depending on the emissions scenario. When both types of adaptive responses were applied, up to 14% more reef cells avoided high-frequency bleaching by 2100. However, temporary increases in bleaching thresholds alone only delayed the occurrence of high-frequency bleaching by ca. 10 years in all but the lowest emissions scenario. Future research should test the rate and limit of different adaptive responses for coral species across latitudes and

  12. 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.

  13. 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.

  14. Additional paper waste in pulping sludge for biohydrogen production by heat-shocked sludge.

    Science.gov (United States)

    Chairattanamanokorn, Prapaipid; Tapananont, Supachok; Detjaroen, Siriporn; Sangkhatim, Juthatip; Anurakpongsatorn, Patana; Sirirote, Pramote

    2012-01-01

    Dark anaerobic fermentation is an interesting alternative method for producing biohydrogen (H(2)) as a renewable fuel because of its low cost and various usable organic substrates. Pulping sludge from wastewater treatment containing plentiful cellulosic substrate could be feasibly utilized for H(2) production by dark fermentation. The objective of this study was to investigate the optimal proportion of pulping sludge to paper waste, the optimal initial pH, and the optimal ratio of carbon and nitrogen (C/N) for H(2) production by anaerobic seed sludge pretreated with heat. The pulping sludge was pretreated with NaOH solution at high temperature and further hydrolyzed with crude cellulase. Pretreatment of the pulping sludge with 3% NaOH solution under autoclave at 121 °C for 2 h, hydrolysis with 5 FPU crude cellulase at 50 °C, and pH 4.8 for 24 h provided the highest reducing sugar production yield (229.68 ± 2.09 mg/g(TVS)). An initial pH of 6 and a C/N ratio of 40 were optimal conditions for H(2) production. Moreover, the supplement of paper waste in the pulping sludge enhanced the cumulative H(2) production yield. The continuous hydrogen production was further conducted in a glass reactor with nylon pieces as supporting media and the maximum hydrogen production yield was 151.70 ml/g(TVS).

  15. Mechanical characterization of cellulosic thecal plates in dinoflagellates by nanoindentation.

    Science.gov (United States)

    Lau, Ringo K L; Kwok, Alvin C M; Chan, W K; Zhang, T Y; Wong, Joseph T Y

    2007-02-01

    Dinoflagellates constitute an important group of microorganisms. Symbiotic dinoflagellates are responsible for the primary production of coral reef ecosystems and the phenomenon of their demise is known as "coral bleaching." Blooming of the planktonic dinoflagellates is the major cause of "red tides." Many dinoflagellates have prominent membrane-bound thecal plates at their cell cortices. These thecal plates have high cellulose content and are biologically fabricated into various shapes. However, the mechanical properties of theca have not previously been characterized; understanding these properties, including hardness and elastic modulus, will give insights into the ecological significance and biotechnological potential of bio-fabricated structures. A series of nanoindentation tests were performed on various locations of cellulosic thecal plates isolated from the dinoflagellates Alexandrium catenella and Lingulodinium polyedrum. Despite having transparent properties, thecal plates possess mechanical properties comparable to softwood cell walls, implicating their role as a protective cell covering. Consistent measurements were obtained when indentation was performed at various locations, which contrasts with the high variability of cellulose microfibers from plant sources. The present study demonstrated the novel properties of this potential new source of cellulose.

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

    Science.gov (United States)

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

    2015-05-01

    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 assays. In DPPH assay solvent extracts of skin by ethanol (SSE) and ethanol-water (SSEW) showed strong inhibitory activity. The SSEW also showed the highest inhibition percentage of 85.58% by the β-carotene bleaching assay and longest induction time of 4.78 h by the Rancimat method. The large amount of tocopherols and phenolics contained in the skin extract may cause its strong antioxidant ability. The results indicated that the solvent extraction with ethanol-water produced the maximum extraction yield of phenolic and tocopherol compounds from loquat fruit skin and pulp. Furthermore, solvent extraction was the most effective in antioxidant activity of the extracts compared to other extraction techniques.

  17. Comparative pulping of sunflower stalks

    Directory of Open Access Journals (Sweden)

    Valerii Barbash

    2016-03-01

    Full Text Available The procedure of holocellulose content determination in non-wood plant raw materials was developed. The strength properties of pulp obtained from sunflower stalks by neutral-sulphite, soda, alkaline sulphite-anthraquinone-ethanol and peracetic methods of delignification were studied. Methodology of comparison of plant materials delignification methods using new lignin-carbohydrate diagram was proposed. It was shown, that the alkaline sulphite-anthraquinone-ethanol method of pulping is characterized by the highest delignification degree and is the most efficient among the studied methods

  18. Randomized controlled trial of sealed in-office bleaching effectiveness.

    Science.gov (United States)

    Santana, Mário Artur Pereira; Nahsan, Flávia Pardo Salata; Oliveira, Alaíde Hermínia de Aguiar; Loguércio, Alessandro Dourado; Faria-e-Silva, André Luis

    2014-01-01

    Regardless of the high success rate, patients commonly report the occurrence of tooth sensitivity during the in-office bleaching procedures. Recently, it has been demonstrated that using a customized tray (called sealed in-office bleaching technique) reduces peroxide penetration. The aim of this randomized clinical study was to evaluate tooth sensitivity and bleaching efficacy of sealed bleaching, in comparison with a conventional in-office technique. Twenty patients were randomized allocated in two groups in which 35% hydrogen peroxide gel was used in a single 45-min application. For the sealed technique, a customized bleaching tray was fabricated and carefully positioned over the bleaching agent during the session. The color was recorded at a baseline, 7 and 28 days after the bleaching session, using Vita Easy Shade spectrophotometer. Tooth sensitivity was recorded during (20 and 40 min) and immediately after the treatment using a visual analogue scale. The bleaching efficacy was evaluated by repeated-measures ANOVA, while the absolute risk of tooth sensitivity and its intensity were evaluated by Fisher's exact and Mann-Whitney tests, respectively (α=0.05). No significant difference on bleaching efficacy was observed between the conventional (7.4 and 8.1 ΔE) and sealed techniques (7.8 and 8.3 ΔE) at both evaluation periods. No significant difference was observed regarding the absolute risk of tooth sensitivity (p=0.15). Sealed technique showed a significant decrease of sensitivity intensity after 40 min (p=0.03). Sealed bleaching technique was able to reduce the sensitivity intensity during the bleaching procedure, without jeopardizing the bleaching efficacy.

  19. 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.

  20. Photothermal bleaching in time-lapse photoacoustic microscopy

    OpenAIRE

    Gao, Liang; Wang, Lidai; Li, Chiye; Garcia-Uribe, Alejandro; Lihong V. Wang

    2012-01-01

    We studied the phenomenon of photothermal bleaching — a gradual reduction of contrast agent particles during repeated scans in photoacoustic microscopy. The dependence of the photothermal bleaching rate on the excitation pulse energy, pulse duration, and the absorber’s size was determined while the laser focal diameter was held constant. Our results showed that, the dependence of the photothermal bleaching rate on the excitation pulse energy differed before and after the absorbers were raised...

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

    OpenAIRE

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

    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:...

  2. 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.

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

    Science.gov (United States)

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

    2016-02-15

    While many studies of coral bleaching report on broad, regional scale responses, fewer examine variation in susceptibility among coral taxa and changes in community structure, before, during and after bleaching on individual reefs. Here we report in detail on the response to bleaching by a coral community on a highly disturbed reef site south of mainland Singapore before, during and after a major thermal anomaly in 2010. To estimate the capacity for resistance to thermal stress, we report on: a) overall bleaching severity during and after the event, b) differences in bleaching susceptibility among taxa during the event, and c) changes in coral community structure one year before and after bleaching. Approximately two thirds of colonies bleached, however, post-bleaching recovery was quite rapid and, importantly, coral taxa that are usually highly susceptible were relatively unaffected. Although total coral cover declined, there was no significant change in coral taxonomic community structure before and after bleaching. Several factors may have contributed to the overall high resistance of corals at this site including Symbiodinium affiliation, turbidity and heterotrophy. Our results suggest that, despite experiencing chronic anthropogenic disturbances, turbid shallow reef communities may be remarkably resilient to acute thermal stress.

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

    Science.gov (United States)

    Alemu I, Jahson Berhane; Clement, Ysharda

    2014-01-01

    Ocean temperatures are increasing globally and the Caribbean is no exception. An extreme ocean warming event in 2010 placed Tobago's coral reefs under severe stress resulting in widespread coral bleaching and threatening the livelihoods that rely on them. The bleaching response of four reef building taxa was monitored over a six month period across three major reefs systems in Tobago. By identifying taxa resilient to bleaching we propose to assist local coral reef managers in the decision making process to cope with mass bleaching events. The bleaching signal (length of exposure to high ocean temperatures) varied widely between the Atlantic and Caribbean reefs, but regardless of this variation most taxa bleached. Colpophyllia natans, Montastraea faveolata and Siderastrea siderea were considered the most bleaching vulnerable taxa. Interestingly, reefs with the highest coral cover showed the greatest decline reef building taxa, and conversely, reefs with the lowest coral cover showed the most bleaching but lowest change in coral cover with little algal overgrowth post-bleaching.

  5. 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.

  6. Hydrodynamic alignment and assembly of nanofibrils resulting in strong cellulose filaments

    Science.gov (United States)

    Håkansson, Karl M. O.; Fall, Andreas B.; Lundell, Fredrik; Yu, Shun; Krywka, Christina; Roth, Stephan V.; Santoro, Gonzalo; Kvick, Mathias; Prahl Wittberg, Lisa; Wågberg, Lars; Söderberg, L. Daniel

    2014-06-01

    Cellulose nanofibrils can be obtained from trees and have considerable potential as a building block for biobased materials. In order to achieve good properties of these materials, the nanostructure must be controlled. Here we present a process combining hydrodynamic alignment with a dispersion-gel transition that produces homogeneous and smooth filaments from a low-concentration dispersion of cellulose nanofibrils in water. The preferential fibril orientation along the filament direction can be controlled by the process parameters. The specific ultimate strength is considerably higher than previously reported filaments made of cellulose nanofibrils. The strength is even in line with the strongest cellulose pulp fibres extracted from wood with the same degree of fibril alignment. Successful nanoscale alignment before gelation demands a proper separation of the timescales involved. Somewhat surprisingly, the device must not be too small if this is to be achieved.

  7. Dynamic-mechanical and thermomechanical properties of cellulose nanofiber/polyester resin composites.

    Science.gov (United States)

    Lavoratti, Alessandra; Scienza, Lisete Cristine; Zattera, Ademir José

    2016-01-20

    Composites of unsaturated polyester resin (UPR) and cellulose nanofibers (CNFs) obtained from dry cellulose waste of softwood (Pinus sp.) and hardwood (Eucalyptus sp.) were developed. The fiber properties and the influence of the CNFs in the dynamic-mechanical and thermomechanical properties of the composites were evaluated. CNFs with a diameter of 70-90 nm were obtained. Eucalyptus sp. has higher α-cellulose content than Pinus sp. fibers. The crystallinity of the cellulose pulps decreased after grinding. However, high values were still obtained. The chemical composition of the fibers was not significantly altered by the grinding process. Eucalyptus sp. CNF composites had water absorption close to the neat resin at 1 wt% filler. The dynamic-mechanical properties of Eucalyptus sp. CNFs were slightly increased and the thermal stability was improved.

  8. Stimuli-responsive cellulose modified by epoxy-functionalized polymer nanoparticles with photochromic and solvatochromic properties.

    Science.gov (United States)

    Abdollahi, Amin; Rad, Jaber Keyvan; Mahdavian, Ali Reza

    2016-10-05

    Photoresponsive papers are among the fast and simple tools for detection of polarity by solvatochromic and photochromic behaviors upon UV irradiation. Here, a new, green and facile modification strategy was employed to prepare novel stimuli-responsive cellulose materials containing spiropyran by mixing microcrystalline cellulose (MCC), as a model compound, with epoxy-functionalized photochromic latex. FTIR analysis, thermal and thermo-mechanical properties were used to confirm the microstructral properties. Crystallographic analysis revealed a decrease in crystallinity of cellulose matrix and approved the incorporation of photochromic copolymer. Then stimuli-responsive papers were prepared by using pulp paper as the cellulosic matrix and their smart characteristics were studied under UV irradiation while dried or immersed into some polar and non-polar solvents. Different color changes were observed and investigated by solid-state UV-vis spectroscopy. These significant results were attributed to the efficient chemical modification and confirmed by SEM, EDX and nitrogen mapping analyses.

  9. 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.

  10. 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.

  11. 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%.

  12. 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.)

  13. 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.

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

    OpenAIRE

    G. Dishon; Fisch, J; Horn, I.; K Kaczmarek; Bijma, J.; Gruber, D.F.; 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...

  15. 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.

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

    OpenAIRE

    G. Dishon; Fisch, J; Horn, I.; K Kaczmarek; Bijma, J.; Gruber, D.F.; 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...

  17. 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.

  18. 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.

  19. 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.

  20. Electrically conductive lines on cellulose nanopaper for flexible electrical devices

    Science.gov (United States)

    Hsieh, Ming-Chun; Kim, Changjae; Nogi, Masaya; Suganuma, Katsuaki

    2013-09-01

    Highly conductive circuits are fabricated on nanopapers composed of densely packed 15-60 nm wide cellulose nanofibers. Conductive materials are deposited on the nanopaper and mechanically sieved through the densely packed nanofiber networks. As a result, their conductivity is enhanced to the level of bulk silver and LED lights are successfully illuminated via these metallic conductive lines on the nanopaper. Under the same deposition conditions, traditional papers consisting of micro-sized pulp fibers produced very low conductivity lines with non-uniform boundaries because of their larger pore structures. These results indicate that advanced, lightweight and highly flexible devices can be realized on cellulose nanopaper using continuous deposition processes. Continuous deposition on nanopaper is a promising approach for a simple roll-to-roll manufacturing process.

  1. 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

  2. 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

  3. 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.

  4. Integral valorization of Leucaena diversifolia by hydrothermal and pulp processing.

    Science.gov (United States)

    Feria, Manuel J; Alfaro, Ascensión; López, Francisco; Pérez, Antonio; García, Juan C; Rivera, Amanda

    2012-01-01

    Wood from the leguminous tree, Leucaena diversifolia, was subjected to hydrothermal treatment (autohydrolysis) at 160-180 °C for 0-30 min followed by ethanol-soda-anthraquinone delignification. The liquid phase contained 18.65 g of sugars per liter, and the solid phase had a gross heating value of 19.083 MJ/kg, but could also be used as a source of cellulose pulp for the production of paper with tear, burst, and tensile indexes of 2.4 N m2/kg, 2.6 MPa m2/kg and 40.7 kN m/kg, respectively. L. diversifolia lends itself readily to valorization for energy production, and also to integral, fractional exploitation by autohydrolysis and ethanol-soda-anthraquinone delignification, which can additionally bring environmental benefits to cropping zones.

  5. 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.

  6. 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.

  7. 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.

  8. CENTRAL KALIMANTAN’S FAST GROWING SPECIES: SUITABILITY FOR PULP AND PAPER

    Directory of Open Access Journals (Sweden)

    Danang Sudarwoko Adi

    2015-04-01

    Full Text Available Recent studies of fast growing species grown in PT. Sari Bumi Kusuma, Central Kalimantan, show that based on their fiber dimensions there are five species, namely Endospermum diadenum, Dillenia spp., Adinandra dumosa, Adiandra sp., and Nauclea junghuhnii with good potential for pulp and paper production. The fiber length of those five wood species are was more than 2,200 µm on average. This paper studies the physical properties, fiber dimensions and their chemical contents to predict the paper and pulp quality. The result shows that all of the species were classified in the medium to high density category. All species were classified into the first class quality for pulp and paper. Based on chemical contents, Dillenia sp. is the most suitable species due to its high value of holocellulose and a-cellulose, low lignin content, and its fiber length is about 3,119 µm on average. A. dumosa also has good opportunities because it had the longest fiber lengths (3,137 µm on average and high value of holocellulose, even though it has the highest lignin content. While Nuclea junghuhnii is less suitable due to low values of holocellulose and a-cellulose.

  9. 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)

  10. Conductivity of Cellulose Acetate Membranes from Pandan Duri Leaves (Pandanus tectorius for Li-ion Battery

    Directory of Open Access Journals (Sweden)

    Laksono Endang W.

    2016-01-01

    Full Text Available The purpose of this research is to know the influence of lithium chloride composition on membrane conductivity. Cellulose was extracted from pandan duri leaves (P. tectorius by dilute alkaline and bleaching with 0.5% NaOCl followed by synthesis of cellulose acetate using acetic anhydride as acetylating agent, acetic acid as solvent and sulfuric acid as catalyst. The membranes were prepared by casting polymer solution method and the composition of CA/LiCl were 60/40, 65/35, 70/30, 75/25, 80/20 and 100/0. Structural analysis was carried out by FTIR and X-ray diffraction. The conductivity was measured using Elkahfi 100. The highest conductivity of cellulose acetate membrane was 2.20 × 10-4 S cm-1 that measured at room temperature for 65/35 composition

  11. PROPERTIES OF BACTERIAL CELLULOSE AND ITS INFLUENCE ON THE PHYSICAL PROPERTIES OF PAPER

    Directory of Open Access Journals (Sweden)

    Wen-Hua Gao

    2011-02-01

    Full Text Available Bacterial cellulose is a promising source of biodegradable polymers having high purity. The time required to disperse bacterial cellulose wet membranes was studied, along with evaluation by infrared spectroscopy and thermal analysis of the dispersed bacterial fiber and tests of the physical properties of the sheet. The results showed that bacterial cellulose wet membrane can be dispersed well, forming fibers when the dispersing time was 3 minutes at a suitable concentration. FT-IR results showed that the composition of bacterial fiber is similar to that of bleached softwood fibers. Thus, the morphology, thermal performance, and the length of bacterial fibers are significantly different. The sheets’ physical properties show that with the increasing dosage of bacterial fibers (relative to softwood fiber, the properties of tensile index, tear index, burst index, and stiffness greatly improve, while the porosity and the relative water absorption decrease.

  12. Utilization of residues from agro-forest industries in the production of high value bacterial cellulose.

    Science.gov (United States)

    Carreira, Pedro; Mendes, Joana A S; Trovatti, Eliane; Serafim, Luísa S; Freire, Carmen S R; Silvestre, Armando J D; Neto, Carlos Pascoal

    2011-08-01

    Bacterial cellulose (BC), a very peculiar form of cellulose, is gaining considerable importance due to its unique properties. In this study, several residues, from agro-forestry industries, namely grape skins aqueous extract, cheese whey, crude glycerol and sulfite pulping liquor were evaluated as economic carbon and nutrient sources for the production of BC. The most relevant BC amounts attained with the residues from the wine and pulp industries were 0.6 and 0.3 g/L, respectively, followed by biodiesel crude residue and cheese whey with productions of about, 0.1 g/L after 96 h of incubation. Preliminary results on the addition of other nutrient sources (yeast extract, nitrogen and phosphate) to the residues-based culture media indicated that, in general, these BC productions could be increased by ~200% and ~100% for the crude glycerol and grape skins, respectively, after the addition organic or inorganic nitrogen.

  13. Evaluation of the bleached human enamel by Scanning Electron Microscopy

    DEFF Research Database (Denmark)

    Miranda, Carolina Baptista; Pagani, Clovis; Benetti, Ana Raquel

    2005-01-01

    Since bleaching has become a popular procedure, the effect of peroxides on dental hard tissues is of great interest in research. Purpose: The aim of this in vitro study was to perform a qualitative analysis of the human enamel after the application of in-office bleaching agents, using Scanning El...

  14. 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.…

  15. The Bleaching Syndrome: The Role of Educational Intervention

    Science.gov (United States)

    Hall, Ronald E.

    2016-01-01

    Per the Bleaching Syndrome, people of color, including African, Asian, and Latino Americans, are both victims and perpetrators of color discrimination. The Bleaching Syndrome encompasses perceptual, psychological, and behavioral sectors that affect students' schooling experiences. Education professionals, including teachers, administrators, and…

  16. The effects of habitat on coral bleaching responses in Kenya.

    Science.gov (United States)

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

    2010-06-01

    This study examines the bleaching responses of scleractinian corals at four sites in Kenya (Kanamai, Vipingo, Mombasa and Nyali) representing two distinct lagoon habitats (relatively shallow and relatively deep). Bleaching incidence was monitored for the whole coral community, while zooxanthellae densities and chlorophyll levels were monitored for target species (Pocillopora damicornis, Porites lutea, and Porites cylindrica) during a non-bleaching year (2006) and a year of mild-bleaching (2007). Differences in bleaching responses between habitats were observed, with shallower sites Kanamai and Vipingo exhibiting lower bleaching incidence than deeper sites Nyali and Mombasa. These shallower lagoons display more fluctuating thermal and light environments than the deeper sites, suggesting that corals in the shallower lagoons have acclimatized and/or adapted to the fluctuating environmental conditions they endure on a daily basis and have become more resistant to bleaching stress. In deeper sites that did exhibit higher bleaching (Mombasa and Nyali), it was found that coral recovery occurred more quickly in the protected area than in the non-protected area.

  17. 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.

  18. The Relationship Between Organic Loading and Effects on Fish Reproduction for Pulp Mill Effluents Across Canada.

    Science.gov (United States)

    Martel, Pierre H; O'Connor, Brian I; Kovacs, Tibor G; Van Den Heuvel, Michael R; Parrott, Joanne L; McMaster, Mark E; MacLatchy, Deborah L; Van Der Kraak, Glen J; Hewitt, L Mark

    2017-02-21

    This study builds upon the work of a multiagency consortium tasked with determining cost effective solutions for the effects of pulp mill effluents on fish reproduction. A laboratory fathead minnow egg production test and chemical characterization tools were used to benchmark eighty-one effluents from twenty mills across Canada, representing the major pulping, bleaching and effluent treatment technologies. For Kraft and mechanical pulp mills, effluents containing less than 20 mg/L BOD5 were found to have the greatest probability of having no effects. Organic loading, expressed as the total detected solvent-extractable components by gas chromatography/mass spectrometry (GC/MS), also correlate with decreased egg laying. Exceptions were found for specific Kraft, mechanical and sulfite mills, suggesting yet unidentified, causative agents are involved. Recycled fibre mill effluents, tested for the first time, were found to have little potential for reproductive effects despite large variations in BOD5 and the GC/MS profiles. Effluent treatment systems across all production types were generally efficient, achieving a combined 82-98 % BOD5 removal. Further reductions of final effluent organic loadings towards the target of less than 20 mg/L are recommended and can be realized through biotreatment optimization, the reduction of organic losses associated with production upsets and selecting best available technologies that reduce organic loadings to biotreatment.

  19. Hot Water Extraction of Corn Stover: Hemicellulose Fractionation and its Effect on Subsequent Soda-AQ Pulping

    Directory of Open Access Journals (Sweden)

    Heli Cheng

    2014-03-01

    Full Text Available Fractionation of lignocellulosic biomass is an important process in producing biofuels. In this study, hot water extraction of corn stover hemicellulose was carried out at 150, 160, and 170 °C. Variations of sugar content in the hydrolysate under different holding time were detected. The contents of furfural and 5-hydroxymethyl-2-furaldehyde generated during the extraction were also determined. Results showed that the main composition of the hydrolysate was xylo-oligosaccharide; the yield of oligosaccharides first increased as holding time was prolonged. After extraction at 160 °C for 210 min, 70.2% of the total xylan was dissolved, with the generation of furfural (0.90 g/L and 5-hydroxymethyl-2-furaldehyde (0.10 g/L. The effects of extraction on alkali pulping and bleaching were also investigated. Results indicated that soda-AQ pulp obtained from the extracted material had poorer tensile and burst strengths but better tear strength.

  20. 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

  1. 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.

  2. Highly transparent films from carboxymethylated microfibrillated cellulose: The effect of multiple homogenization steps on key properties

    DEFF Research Database (Denmark)

    Siró, Istvan; Plackett, David; Hedenqvist, M.

    2011-01-01

    We produced microfibrillated cellulose by passing carboxymethylated sulfite-softwood-dissolving pulp with a relatively low hemicellulose content (4.5%) through a high-shear homogenizer. The resulting gel was subjected to as many as three additional homogenization steps and then used to prepare so...... of homogenization, whereas the mean tensile strength, modulus of elasticity, and strain at break were increased by two or three extra homogenization steps. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011...

  3. Physicochemical of microcrystalline cellulose from oil palm fronds as potential methylene blue adsorbents.

    Science.gov (United States)

    Hussin, M Hazwan; Pohan, Nurul Aqilah; Garba, Zaharaddeen N; Kassim, M Jain; Rahim, Afidah Abdul; Brosse, Nicolas; Yemloul, Mehdi; Fazita, M R Nurul; Haafiz, M K Mohamad

    2016-11-01

    The present study sheds light on the physical and chemical characteristics of microcrystalline cellulose (MCC) isolated from oil palm fronds (OPF) pulps. It was found that the OPF MCC was identified as cellulose II polymorph, with higher crystallinity index than OPF α-cellulose (CrIOPFMCC: 71%>CrIOPFα-cellulose: 47%). This indicates that the acid hydrolysis allows the production of cellulose that is highly crystalline. BET surface area of OPF MCC was found to be higher than OPF α-cellulose (SBETOPFMCC: 5.64m(2)g(-1)>SBETOPFα-cellulose:Qa(0) 2.04m(2)g(-1)), which corroborates their potential as an adsorbent. In batch adsorption studies, it was observed that the experimental data fit well with Langmuir adsorption isotherm in comparison to Freundlich isotherm. The monolayer adsorption capacity (Qa(0)) of OPF MCC was found to be around 51.811mgg(-1) and the experimental data fitted well to pseudo-second-order kinetic model.

  4. 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.

  5. Effects of Lignophenols on Mechanical Performance of Biocomposites Based on Polyhydroxybutyrate (PHB and Polypropylene (PP Reinforced with Pulp Fibers

    Directory of Open Access Journals (Sweden)

    Hao Ren

    2014-11-01

    Full Text Available The effects of lignophenols and pulp fibers as reinforcing elements in biocomposites were studied with poly-(3-hydroxybutyrate (PHB biopolymers and polystyrene (PS matrix materials. Lignophenols and (NH2(CH23Si(OC2H53 were compared as plasticizing or compatibilizing additives in tests of composite properties. PHB and PP were blended with pulp fiber cellulose and lignophenol by torque rheometer, and the test specimens were processed via injection moulding. Various testing methods, including tensile and impact tests, SEM, XRD, TGA, and ART-FTIR were used to investigate the properties of the composites. PHB and PP-cellulose fiber composites with strong mechanical properties could be created by using a torque rheometer as a mixer at 190 ºC with very short mixing times. The (NH2(CH23Si(OC2H53 was found to improve the mechanical features of the PP, but not very obviously for both tensile and impact strengths of PHB. However, the lignophenols positively affected the PHB-pulp fiber composites. In summary, a novel method has been demonstrated for creating biodegradable composites with pulp fibers in the absence of a coupling agent, and lignophenols may be applicable as an additive in the cases described in this study.

  6. 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.

  7. [Pulp response to restorative materials].

    Science.gov (United States)

    Advokaat, J G

    1990-03-01

    Restorations may affect the pulp negatively, rather due to microleakage than to toxic properties of the materials used. Hyperalgesia occurs more frequently after restoration with composite resins than with amalgam, though the resins in contrast to amalgam may be bonded to the enamel margins. A number of recommendations are presented in order to minimize the marginal gap between cavity walls and amalgam and to prevent marginal fracture.

  8. 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

  9. Acid hydrolysis of cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Salazar, H.

    1980-12-01

    One of the alternatives to increase world production of etha nol is by the hydrolysis of cellulose content of agricultural residues. Studies have been made on the types of hydrolysis: enzimatic and acid. Data obtained from the sulphuric acid hydrolysis of cellulose showed that this process proceed in two steps, with a yield of approximately 95% glucose. Because of increases in cost of alternatives resources, the high demand of the product and the more economic production of ethanol from cellulose materials, it is certain that this technology will be implemented in the future. At the same time further studies on the disposal and reuse of the by-products of this production must be undertaken.

  10. Effect of Mild Acid Hydrolysis Parameters on Properties of Microcrystalline Cellulose

    Directory of Open Access Journals (Sweden)

    Kari Mikael Vanhatalo

    2014-06-01

    Full Text Available The effects of mild kraft pulp hydrolysis conditions (reaction time, temperature, pulp consistency, and acid dosage with sulfuric acid (H2SO4 on the properties of microcrystalline cellulose (MCC were investigated. The degree of polymerization (DP of cellulose rapidly decreased at the initiation of hydrolysis and leveled off after a certain reaction time, depending on the hydrolysis conditions. The intensity of the hydrolysis treatment greatly affected the cellulose particle size. Compared to the intensive treatment, the mild conditions resulted in a broader particle size distribution, while smaller particles with a narrow size distribution were obtained under severe conditions. However, the particle size leveled off at a hydrolysis factor (P-factor of 300. The results suggest that after a certain P-factor (300, severe hydrolysis conditions have no advantage over mild ones as related to the MCC particle properties. Because of favourable reaction conditions (short delay time, moderate temperature, and small amounts of chemicals, this method can be implemented on an industrial scale in a chemical pulp mill.

  11. Solid-State Fermentation: an Alternative to Improve the Nutritive Value of Coffee Pulp

    Science.gov (United States)

    Peñaloza, Walter; Molina, Mario R.; Brenes, Roberto Gomez; Bressani, Ricardo

    1985-01-01

    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°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. PMID:16346724

  12. 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.

  13. Characterization of vine shoots, cotton stalks, Leucaena leucocephala and Chamaecytisus proliferus, and of their ethyleneglycol pulps.

    Science.gov (United States)

    Jiménez, Luis; Pérez, Antonio; de la Torre, María Jesús; Moral, Ana; Serrano, Luis

    2007-12-01

    We characterized vine shoots, cotton stalks, Leucaena leucocephala and Chamaecytisus proliferus as pulping raw materials and found C. proliferus and cotton stalks to be the best for the intended purpose on the grounds of their increased contents in holocellulose (79.73% and 72.86%) and alpha-cellulose (45.37% and 58.48%), and their decreased contents in ethanol-benzene extractables (2.64% and 1.42%), hot water solubles (2.79% and 3.33%) and 1% soda solubles (16.67% and 20.34%). These properties resulted in increased pulp yields and hence in efficient use of these two types of raw material. The previous raw materials were pulped by using an ethyleneglycol concentration of 65% at 180 degrees C for 75min, followed by beating at 1500 revolutions in a PFI refiner. The paper sheets obtained were characterized and those from C. proliferus found to be the best overall as they exhibited an increased breaking length (4644m), stretch (2.87%), burst index (2.46kN/g) tear index (0.33mNm(2)/g) and brightness (49.92% ISO); in addition C. proliferus pulp was obtained with a high-yield (62.88%). On the other hand, vine shoots provided the poorest results among the studied raw materials.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. Is It Necessary to Prepare the Enamel before Dental Bleaching?

    Science.gov (United States)

    Araújo, Erika Michele dos Santos; Garone-Netto, Narciso

    2017-01-01

    The aim of this in vitro study was to assess the influence of distinct surface treatments on the microhardness and color of enamel that will be bleached. Surface treatments are tested, accordingly: G1, no treatment; G2, 2% sodium fluoride; G3, casein phosphopeptide paste; G4, 2% fluoride+Nd:YAG laser. Forty blocks from bovine teeth composed the sample that were tested in Knoop microhardness (n = 10) and in color change (n = 10). After 24 h, bleaching with 35% hydrogen peroxide was performed for 45 min. Microhardness and color changes (using parameters ΔE, ΔL, Δa, and Δb) were assessed before and after bleaching. The data were analyzed by two-way ANOVA and Tukey's test (p microhardness occurred immediately after bleaching in all groups, being greater in G1. Enamel color changed in all groups. Immediately after bleaching, there was a decrease on enamel microhardness. However, after 7 days, some of those specimens previously treated before bleaching significantly recovered their initial microhardness without influencing the esthetic results of bleaching. PMID:28280508

  20. Cellulose Microfibril Formation by Surface-Tethered Cellulose Synthase Enzymes.

    Science.gov (United States)

    Basu, Snehasish; Omadjela, Okako; Gaddes, David; Tadigadapa, Srinivas; Zimmer, Jochen; Catchmark, Jeffrey M

    2016-02-23

    Cellulose microfibrils are pseudocrystalline arrays of cellulose chains that are synthesized by cellulose synthases. The enzymes are organized into large membrane-embedded complexes in which each enzyme likely synthesizes and secretes a β-(1→4) glucan. The relationship between the organization of the enzymes in these complexes and cellulose crystallization has not been explored. To better understand this relationship, we used atomic force microscopy to visualize cellulose microfibril formation from nickel-film-immobilized bacterial cellulose synthase enzymes (BcsA-Bs), which in standard solution only form amorphous cellulose from monomeric BcsA-B complexes. Fourier transform infrared spectroscopy and X-ray diffraction techniques show that surface-tethered BcsA-Bs synthesize highly crystalline cellulose II in the presence of UDP-Glc, the allosteric activator cyclic-di-GMP, as well as magnesium. The cellulose II cross section/diameter and the crystal size and crystallinity depend on the surface density of tethered enzymes as well as the overall concentration of substrates. Our results provide the correlation between cellulose microfibril formation and the spatial organization of cellulose synthases.

  1. 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.

  2. 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

  3. 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.

  4. Anaerobic digestion of pulp and paper mill wastewater and sludge.

    Science.gov (United States)

    Meyer, Torsten; Edwards, Elizabeth A

    2014-11-15

    Pulp and paper mills generate large amounts of waste organic matter that may be converted to renewable energy in form of methane. The anaerobic treatment of mill wastewater is widely accepted however, usually only applied to few selected streams. Chemical oxygen demand (COD) removal rates in full-scale reactors range between 30 and 90%, and methane yields are 0.30-0.40 m(3) kg(-1) COD removed. Highest COD removal rates are achieved with condensate streams from chemical pulping (75-90%) and paper mill effluents (60-80%). Numerous laboratory and pilot-scale studies have shown that, contrary to common perception, most other mill effluents are also to some extent anaerobically treatable. Even for difficult-to-digest streams such as bleaching effluents COD removal rates range between 15 and 90%, depending on the extent of dilution prior to anaerobic treatment, and the applied experimental setting. Co-digestion of different streams containing diverse substrate can level out and diminish toxicity, and may lead to a more robust microbial community. Furthermore, the microbial population has the ability to become acclimated and adapted to adverse conditions. Stress situations such as toxic shock loads or temporary organic overloading may be tolerated by an adapted community, whereas they could lead to process disturbance with an un-adapted community. Therefore, anaerobic treatment of wastewater containing elevated levels of inhibitors or toxicants should be initiated by an acclimation/adaptation period that can last between a few weeks and several months. In order to gain more insight into the underlying processes of microbial acclimation/adaptation and co-digestion, future research should focus on the relationship between wastewater composition, reactor operation and microbial community dynamics. The potential for engineering and managing the microbial resource is still largely untapped. Unlike in wastewater treatment, anaerobic digestion of mill biosludge (waste activated

  5. Calculating cellulose diffraction patterns

    Science.gov (United States)

    Although powder diffraction of cellulose is a common experiment, the patterns are not widely understood. The theory is mathematical, there are numerous different crystal forms, and the conventions are not standardized. Experience with IR spectroscopy is not directly transferable. An awful error, tha...

  6. 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

  7. 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

  8. Salt, chloride, bleach, and innate host defense.

    Science.gov (United States)

    Wang, Guoshun; Nauseef, William M

    2015-08-01

    Salt provides 2 life-essential elements: sodium and chlorine. Chloride, the ionic form of chlorine, derived exclusively from dietary absorption and constituting the most abundant anion in the human body, plays critical roles in many vital physiologic functions, from fluid retention and secretion to osmotic maintenance and pH balance. However, an often overlooked role of chloride is its function in innate host defense against infection. Chloride serves as a substrate for the generation of the potent microbicide chlorine bleach by stimulated neutrophils and also contributes to regulation of ionic homeostasis for optimal antimicrobial activity within phagosomes. An inadequate supply of chloride to phagocytes and their phagosomes, such as in CF disease and other chloride channel disorders, severely compromises host defense against infection. We provide an overview of the roles that chloride plays in normal innate immunity, highlighting specific links between defective chloride channel function and failures in host defense.

  9. Study of Melanin Bleaching After Immunohistochemistry of Melanin-containing Tissues

    OpenAIRE

    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...

  10. Tumorigenicity of cellulose fibers injected into the rat peritoneal cavity.

    Science.gov (United States)

    Cullen, R T; Miller, B G; Clark, S; Davis, J M G

    2002-07-01

    Cellulose fibers, along with many other organic fibers, are durable. Therefore, if inhaled, they have the potential to persist within the lung, and may then cause disease. Here we report the effects of injecting high-purity cellulose fibers into the abdominal cavity of rats. A respirable fraction of cellulose fiber was collected from an aerosol of a thermo-mechanically-processed wood pulp. A sample of respirable crocidolite asbestos, known to produce mesotheliomas in rats, was used as a positive control. Total doses of 10(6), 10(7), 10(8), or 10(9) WHO fibers were injected intraperitoneally as 3 weekly aliquots. A negative control was provided by phosphate-buffered saline used to suspend the fibers for injection. There were 50 rats per treatment group except for the 10(8) and 10(9) fibers crocidolite groups which were reduced to 26 rats because of the expectation of high tumor incidence in these groups. The two higher doses of crocidolite asbestos caused greatly reduced survival compared to the saline controls. With cellulose there was a much less marked effect on survival. In the highest dose cellulose group, multiple large nodules (granulomas) and widespread adhesions (bands of new tissue connecting organs to each other and to the abdominal wall) were present in all animals. Granulomas were not observed in the 10(9) fibers crocidolite group. More than 80% of animals in the 10(8) and 10(9) crocidolite asbestos groups had mesotheliomas, a type of tumor sometimes observed in people exposed to asbestos. In contrast, there were only 2 animals in the cellulose groups with mesothelioma tumors, 1 in the 10(7) and 1 in the 10(8) groups. However, 9 (18%) of the 10(9) cellulose group had malignant tumors that, in contrast to the usual pattern of mesothelioma development following treatment with mineral fibers in rats, showed no obvious involvement of mesothelial tissues, were not associated with blood-stained ascites fluid, and were thus classified as sarcomas. This study

  11. 竹材用于生产溶解浆的试验研究%Study on Dissolving Pulp of Bamboo

    Institute of Scientific and Technical Information of China (English)

    马伟良; 臧贻朋

    2012-01-01

    将竹材与木材原料相对比,分析了竹原料的特性,直观地说明了竹材用于溶解浆生产的可行性.结合工厂的现有工艺流程,以造纸竹浆为原料,优化了其蒸煮、漂白等工艺条件,制取了溶解浆.结果表明:所得浆粕甲种纤维素含量高、白度高、反应性能较好,适用于黏胶纤维用浆粕的生产.%The characteristic of bamboo pulp fiber is similar to wood pulp fiber raw material. In this paper, the bamboo was compared with wood raw material. The results intuitively describe the feasibility of bamboo raw material for the production of dissolving pulp. Then, combined with the present plant process, the bamboo pulp is used as raw material for papermaking, and the cooking and bleaching conditions are optimized. The results show that the dissolving pulp has high A fiber content, high whiteness and good reaction performance. And it is suitable for the production of viscose fiber.

  12. 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.

  13. FTIR spectroscopy and X-ray powder diffraction characterization of microcrystalline cellulose obtained from alfa fibers

    Directory of Open Access Journals (Sweden)

    Trache D.

    2013-07-01

    Full Text Available Many cereal straws have been used as raw materials for the preparation of microcrystalline cellulose (MCC. These raw materials were gradually replaced with wood products; nevertheless about 10% of the world overall pulp production is obtained from non-wood raw material. The main interest in pulp made from straw is that it provides excellent fibres for different industries with special properties, and that it is the major available source of fibrous raw material in some geographical areas. The aim of the present work was to characterize microcrystalline cellulose prepared from alfa fibers using the hydrolysis process. The products obtained are characterized with FTIR spectroscopy and X-ray powder diffraction. As a result, FTIR spectroscopy is an appropriate technique for studying changes occurred by any chemical treatment. The spectrum of alfa grass stems shows the presence of lignin and hemicelluloses. However, the cellulose spectrum indicates that the extraction of lignin and hemicellulose was effective. The X-ray analysis indicates that the microcrystalline cellulose is more crystalline than the source material.

  14. 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

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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%.

  2. Bleaching of the red anthocyanin induced by superoxide radical.

    Science.gov (United States)

    Yamasaki, H; Uefuji, H; Sakihama, Y

    1996-08-01

    Red anthocyanin prepared from petals of Hibiscus rosa-sinensis L. was photobleached in the EDTA-riboflavin system. The rate of bleaching monitored at 565 nm depended on the light intensity and EDTA concentrations. Anaerobic conditions and/or addition of superoxide dismutase prevented the bleaching of anthocyanin, whereas mannitol and catalase did not. A similar bleaching was observed under dark conditions in the xanthine-xanthine oxidase system. The results indicate that anthocyanin is bleached by the nonenzymatic reaction with the superoxide radical and suggest that the pigment can function as an antioxidant. The antioxidative efficiency of cyanidin to superoxide was 10-fold higher than that of cyanidin-3-sophoroside as a Hibiscus anthocyanin.

  3. 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.

  4. 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

  5. 29 CFR 1910.261 - Pulp, paper, and paperboard mills.

    Science.gov (United States)

    2010-07-01

    ... off. (20) Furnace room. Exhaust ventilation shall be provided where niter cake is fed into a rotary...) Bleach mixing rooms. (i) The room in which the bleach powder is mixed shall be provided with...

  6. 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.

  7. 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.

  8. Non-cellulosic polysaccharides from cotton fibre are differently impacted by textile processing.

    Science.gov (United States)

    Runavot, Jean-Luc; Guo, Xiaoyuan; Willats, William G T; Knox, J Paul; Goubet, Florence; Meulewaeter, Frank

    2014-01-01

    Cotton fibre is mainly composed of cellulose, although non-cellulosic polysaccharides play key roles during fibre development and are still present in the harvested fibre. This study aimed at determining the fate of non-cellulosic polysaccharides during cotton textile processing. We analyzed non-cellulosic cotton fibre polysaccharides during different steps of cotton textile processing using GC-MS, HPLC and comprehensive microarray polymer profiling to obtain monosaccharide and polysaccharide amounts and linkage compositions. Additionally, in situ detection was used to obtain information on polysaccharide localization and accessibility. We show that pectic and hemicellulosic polysaccharide levels decrease during cotton textile processing and that some processing steps have more impact than others. Pectins and arabinose-containing polysaccharides are strongly impacted by the chemical treatments, with most being removed during bleaching and scouring. However, some forms of pectin are more resistant than others. Xylan and xyloglucan are affected in later processing steps and to a lesser extent, whereas callose showed a strong resistance to the chemical processing steps. This study shows that non-cellulosic polysaccharides are differently impacted by the treatments used in cotton textile processing with some hemicelluloses and callose being resistant to these harsh treatments.

  9. 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

  10. 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.

  11. Effluent monitoring at a bleached kraft mill: directions for best management practices for eliminating effects on fish reproduction.

    Science.gov (United States)

    Martel, Pierre H; Kovacs, Tibor G; O'connor, Brian I; Semeniuk, Sharon; Hewitt, L Mark; Maclatchy, Deborah L; McMaster, Mark E; Parrott, Joanne L; van den Heuvel, Michael R; Van Der Kraak, Glen J

    2011-01-01

    A long-term monitoring study was conducted on effluents from a bleached kraft pulp and paper mill located in Eastern Canada. The study was designed to gain insights into temporal effluent variability with respect to fish reproduction as it related to production upsets, mill restarts and conditions affecting biological treatment performance. Final effluent quality was monitored between February 2007 and May 2009 using biochemical and chemical oxygen demand, total suspended solids, resin and fatty acids, a gas chromatographic profiling index, and the presence of methyl substituted 2-cyclopentenones. Selected effluent samples were evaluated for effects on fish reproduction (egg production) using a shortened version of the adult fathead minnow reproductive test. The events relating to negative effects on fish reproduction were upsets of the pulping liquor recovery system resulting in black liquor losses, operational upsets of the hardwood line resulting in the loss of oxygen delignification filtrates, and conditions that reduced the performance of biological treatment (e.g., mill shutdown and low ambient temperatures). The reductions in egg production observed in fathead minnow were associated with biochemical oxygen demand values > 20 mg/L, GC profiling indices > 1.2 and the presence of methyl-substituted 2-cyclopentenones at concentrations > 100 μg/L. This study demonstrated the importance of both in-plant measures for controlling the loss of organics as well as the optimum operation of biological effluent treatment for eliminating effluent-related effects on fish reproduction (egg production) in the laboratory.

  12. Influence of HNO3/H3PO4-NANO2 mediated oxidation on the structure and properties of cellulose fibers.

    Science.gov (United States)

    Xu, Yunhui; Liu, Xin; Liu, Xuelan; Tan, Jiulong; Zhu, Hongling

    2014-10-13

    The bamboo pulp cellulose fiber was oxidized with HNO3/H3PO4-NaNO2 mixture to obtain oxidized cellulose containing different levels of carboxyl content and with high yields. The effects of HNO3/H3PO4-NaNO2 mediated oxidation on structure and properties of the fiber were investigated. The results showed that an increase in carboxyl content and weight loss of oxidized fibers appeared with increasing oxidation time. Compared with the original cellulose, the oxidized fibers had lower crystallinity (29-40%) and thermal stability. The patterns of (13)C NMR, X-ray diffraction and other testing methods revealed that the oxidation mostly occurred at C6 primary hydroxyl groups of cellulose. Moreover, an oxidized fiber with 94.14-98.59% of high yields and 1.13-3.56% of carboxyl content was obtained in the range of oxidation time from 15 to 60 min, while its mechanical properties did not change significantly. This work presented some detailed information about structure-property correlations of oxidized bamboo pulp cellulose fibers and was useful in planning applications of these products.

  13. Overcoming the Recalcitrance for the Conversion of Kenaf Pulp to Glucose via Microwave-Assisted Pre-Treatment Processes

    Directory of Open Access Journals (Sweden)

    Miguel A. Hurtado

    2011-02-01

    Full Text Available This study evaluates the pre-treatment of cellulose from kenaf plant to yield sugar precursors for the production of ethanol or butanol for use as biofuel additives. In order to convert the crystalline cellulosic form to the amorphous form that can undergo enzymatic hydrolysis of the glycosidic bond to yield sugars, kenaf pulp samples were subjected to two different pre-treatment processes. In the acid pre-treatment, the pulp samples were treated with 37.5% hydrochloric acid in the presence of FeCl3 at 50 °C or 90 °C whereas in the alkaline method, the pulp samples were treated with 25% sodium hydroxide at room temperature and with 2% or 5% sodium hydroxide at 50 °C. Microwave-assisted NaOH-treatment of the cellulose was also investigated and demonstrated to be capable of producing high glucose yield without adverse environmental impact by circumventing the use of large amounts of concentrated acids i.e., 83–85% phosphoric acid employed in most digestion processes. The treated samples were digested with the cellulase enzyme from Trichoderma reesei. The amount of glucose produced was quantified using the QuantichromTM glucose bioassay for assessing the efficiency of glucose production for each of the treatment processes. The microwave-assisted alkaline pre-treatment processes conducted at 50 °C were found to be the most effective in the conversion of the crystalline cellulose to the amorphous form based on the significantly higher yields of sugar produced by enzymatic hydrolysis compared to the untreated sample.

  14. 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.

  15. 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.

  16. Study of fiber materialization from unutilized cellulose and fungal chitosan resources; Miriyo cellulose oyobi biseibutsu chitosan shigen no sen`i sozaika no kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Kubo, T.; Hosokawa, J.; Yoshihira, K.; Nishiyama, M.; Kobayashi, T.; Akamatsu, I.; Kobayashi, Y.; Kimura, Y. [Shikoku National Industrial Research Institute, Kagawa (Japan)

    1996-06-25

    Unutilized cellulose and fungal chitosan resources were examined from the viewpoints of resource protection and effective utilization. As for Hevea brasilliensis wastes (by-product of natural rubber extraction) and Leucaena latisliqua timber, it is difficult to reduce them into fibrils because their fibers are short and thick, and therefore they are not fit for treatment by pulping machines. In this study, they were subjected to the CTMP (chemi-thermomechanical pulp) method which employs alkaline sulphites in the pre-treatment, and the result was a fibril longer per average weight, flexible and strong enough to be pulp for newsprint paper. A sheet making use of alkali-insoluble cell walls (hollow filament) of Rhizopus acetoinus containing chitinous substances, chitosan in particular, and a sheet utilizing this material and natural pulp fiber, were also studied. Optimal conditions were identified under which fungi containing more chitosan in their cell walls could be cultured en masse with ease. The sheets using this hollow filament material adsorbed heavy metal. This will make a fine material for functional sheets if allowed to adsorb functional materials before fabrication into sheets. 72 refs., 42 figs., 24 tabs.