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

Science.gov (United States)

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

2015-01-01

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

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

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....

Properties of cellulose derivatives produced from radiation-Modified cellulose pulps

International Nuclear Information System (INIS)

Iller, Edward; Stupinska, Halina; Starostka, Pawel

2007-01-01

The aim of project was elaboration of radiation methods for properties modification of cellulose pulps using for derivatives production. The selected cellulose pulps were exposed to an electron beam with energy 10 MeV in a linear accelerator. After irradiation pulps underwent the structural and physico-chemical investigations. The laboratory test for manufacturing carboxymethylocellulose (CMC), cellulose carbamate (CC) and cellulose acetate (CA) with cellulose pulps irradiated dose 10 and 15 kGy have been performed. Irradiation of the pulp influenced its depolimerisation degree and resulted in the drop of viscosity of CMC. However, the expected level of cellulose activation expressed as a rise of the substitution degree or increase of the active substance content in the CMC sodium salt was not observed. In the case of cellulose esters (CC, CA) formation, the action of ionising radiation on cellulose pulps with the dose 10 and 15 kGy enables obtaiment of the average values of polimerisation degree as required for CC soluble in aqueous sodium hydroxide solution. The properties of derivatives prepared by means of radiation and classic methods were compared

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

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Zhi Li

2015-03-01

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

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

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Mauro Manfredi

2014-06-01

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

Performance of Schizolobium amazonicum Wood in Bleached Kraft Pulp Production

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Camila Sarto

2015-05-01

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

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

Science.gov (United States)

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

2016-01-01

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

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.

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

Science.gov (United States)

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

2013-12-01

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

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

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Yi Dai

2016-02-01

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

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.

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

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Yan-Lan Liu

2013-11-01

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

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

OpenAIRE

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

2010-01-01

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

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.

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

Science.gov (United States)

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

2015-01-01

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

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

Science.gov (United States)

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

2017-12-01

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

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

Science.gov (United States)

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

2012-12-01

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

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

Science.gov (United States)

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

2013-01-01

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

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

Science.gov (United States)

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

2017-12-29

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

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

International Nuclear Information System (INIS)

Rabelo, Marcos Sousa

2009-01-01

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

Biological evaluation of nanosilver incorporated cellulose pulp for hygiene products

Energy Technology Data Exchange (ETDEWEB)

Kavitha Sankar, P.C.; Ramakrishnan, Reshmi; Rosemary, M.J., E-mail: rosemarymj@lifecarehll.com

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. - Highlights: • Different amounts of silver nanoparticles (0.2 g–0.4 g/napkin) were added to cellulose pulp. • The silver nanoparticle incorporated cellulose pulp was proved to be antibacterial by JIS L 1902 method. • The minimum concentration of silver required for antibacterial activity with no cytotoxicity has been found out. • In-vivo vaginal irritation and intracutaneous reactivity studies confirmed the biocompatibility of the material.

Biological evaluation of nanosilver incorporated cellulose pulp for hygiene products

International Nuclear Information System (INIS)

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

2016-01-01

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. - Highlights: • Different amounts of silver nanoparticles (0.2 g–0.4 g/napkin) were added to cellulose pulp. • The silver nanoparticle incorporated cellulose pulp was proved to be antibacterial by JIS L 1902 method. • The minimum concentration of silver required for antibacterial activity with no cytotoxicity has been found out. • In-vivo vaginal irritation and intracutaneous reactivity studies confirmed the biocompatibility of the material.

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.

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

Directory of Open Access Journals (Sweden)

Mehdi Jonoobi

2009-05-01

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

MOLYBDENUM CATALYZED ACID PEROXIDE BLEACHING OF EUCALYPTUS KRAFT PULP

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Marcos S. Rabelo

2008-08-01

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

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

International Nuclear Information System (INIS)

El-Sakhawy, M.M.; Hassan, M.L.

2005-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

El-Sakhawy, M M; Hassan, M L [Cellulose and Paper Dept., National Research Center, Dokki, Cairo (Egypt)

2005-07-01

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

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)

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

International Nuclear Information System (INIS)

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

2015-01-01

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

Production of cellulose nanoparticles from blue agave waste treated with environmentally friendly processes.

Science.gov (United States)

Robles, Eduardo; Fernández-Rodríguez, Javier; Barbosa, Ananda M; Gordobil, Oihana; Carreño, Neftali L V; Labidi, Jalel

2018-03-01

Tequila elaboration leaves two main byproducts that are undervalued (bagasse and leaves). Organosolv pulping and Total Chlorine Free bleaching were integrated to obtain cellulose fibers from agricultural waste which consisted of blue agave bagasse and leaf fibers; together they represent a green process which valorizes biomass waste. The obtained celluloses were characterized by FT-IR, colorimetry, and SEM and their extraction yields were evaluated. These celluloses were used to produce cellulose nanocrystals and cellulose nanofibers. First, an acid hydrolysis was performed in a sonication bath to induce cavitation during the reaction to produce cellulose nanocrystals. Then a high-pressure homogenization was selected to produce cellulose nanofibers. These nanocelluloses were characterized by powder XRD, Nanosizer, zeta potential, NMR, and electronic microscopy. Results showed that cellulose from organosolv pulps bleached with TCF bleaching is suitable for nanocellulose production. Moreover, the use of a new step to separate cellulose nanocrystals resulted in yields almost doubling traditional yields, while the rest of the properties remained within the expected. Copyright © 2018 Elsevier Ltd. All rights reserved.

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

International Nuclear Information System (INIS)

Yuan-Zong Lai

2001-01-01

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

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

Directory of Open Access Journals (Sweden)

Avdhesh Kumar Gangwar

2015-11-01

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

Optimization of Laccase-Aided Chlorine Dioxide Bleaching of Bagasse Pulp

Directory of Open Access Journals (Sweden)

Yong Pei

2015-11-01

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

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

Science.gov (United States)

Junyong Zhu; Ronald Sabo; Xiaolin Luo

2011-01-01

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

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

Science.gov (United States)

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

2018-05-01

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

Dynamic rheology behavior of electron beam-irradiated cellulose pulp/NMMO solution

International Nuclear Information System (INIS)

Zhou Ruimin; Deng Bangjun; Hao Xufeng; Zhou Fei; Wu Xinfeng; Chen Yongkang

2008-01-01

The rheological behavior of irradiated cellulose pulp solution by electron beam was investigated. Storage modulus G', loss modulus G'', the dependence of complex viscosity η* and frequency ω of cellulose solutions were measured by DSR-200 Rheometer (Rheometrics co., USA). The molecular weight of irradiated cellulose was measured via the intrinsic viscosity measurement using an Ubbelohde capillary viscometer. The crystalline structure was studied by FTIR Spectroscopy. The results congruously showed that the molecular weight of pulp cellulose decrease and the molecular weight distribution of cellulose become narrow with increase in the irradiation dose. Moreover, the crystalline structure of the cellulose was destroyed, the force of the snarl between the cellulose molecules weakens and the accessibility of pulp spinning is improved. The study supplies some useful data for spinnability of irradiated cellulose and technical data to the filature industry

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)

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

International Nuclear Information System (INIS)

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

2016-01-01

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

Natural and recombinant fungal laccases for paper pulp bleaching

NARCIS (Netherlands)

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

2004-01-01

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

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

Science.gov (United States)

Van Tran, A

2008-07-01

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

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

International Nuclear Information System (INIS)

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

2010-01-01

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

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

Science.gov (United States)

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

2017-10-01

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

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.

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

Directory of Open Access Journals (Sweden)

Avdhesh Kumar Gangwar

2015-10-01

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

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

Science.gov (United States)

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

2016-08-20

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

New and improved method of investigation using thermal tools for characterization of cellulose from eucalypts pulp

Energy Technology Data Exchange (ETDEWEB)

Lengowski, Elaine Cristina, E-mail: elainelengowski@yahoo.com.br [Laboratório de Anatomia e Qualidade da Madeira – LANAQM, Departamento de Engenharia e Tecnologia Florestal – DETF/Universidade Federal do Paraná, (UFPR), Curitiba, PR (Brazil); Magalhães, Washington Luiz Esteves, E-mail: washington.magalhaes@embrapa.br [Embrapa Florestas, Estrada da Ribeira km 111 P.O. Box 319, 83411-000 Colombo, PR (Brazil); Programa de Pós Graduação em Engenharia de Materiais – PIPE Universidade Federal do Paraná, (UFPR), Curitiba, PR (Brazil); Nisgoski, Silvana, E-mail: silnis@yahoo.com [Laboratório de Anatomia e Qualidade da Madeira – LANAQM, Departamento de Engenharia e Tecnologia Florestal – DETF/Universidade Federal do Paraná, (UFPR), Curitiba, PR (Brazil); Muniz, Graciela Inês Bolzon de, E-mail: graciela.ufpr@gmail.com [Laboratório de Anatomia e Qualidade da Madeira – LANAQM, Departamento de Engenharia e Tecnologia Florestal – DETF/Universidade Federal do Paraná, (UFPR), Curitiba, PR (Brazil); Satyanarayana, Kestur Gundappa [Embrapa Florestas, Estrada da Ribeira km 111 P.O. Box 319, 83411-000 Colombo, PR (Brazil); Lazzarotto, Marcelo, E-mail: marcelo.lazzarotto@embrapa.br [Embrapa Florestas, Estrada da Ribeira km 111 P.O. Box 319, 83411-000 Colombo, PR (Brazil)

2016-08-20

Highlights: • Cellulose was treated to modify its crystallinity. • Cellulose was characterized by X-ray diffraction to evaluate Segal’s index. • TGA and DTA with chemometric tools were used to predict Segal’s index. • MLR model was applied to predict XRD cellulose Segal’s index from TGA curves. • MLR model was applied to predict XRD cellulose Segal’s index from DTA curves. - Abstract: Despite cellulose being the most abundant biopolymer on earth and an important commodity, there is a lack of deeper knowledge about its structure as well as faster and more efficient characterization techniques. This paper presents preparation of nanocellulose from bleached cellulose pulp of Eucalyptus by chemical and mechanical pre-treatments, while the cellulose was given treatment to obtain a great range of crystallinity index. The nanocellulose is characterized by X-ray diffraction to evaluate Segal’s index while chemometric tools by TGA and DTA were used to predict Segal’s index. DTA curves, along with multivariate statistical model, presented better result than TGA. The coefficient of variation and standard error of prediction for the proposed models using external validation samples were in the range of 0.91–0.96 and 4.18–8.71, respectively. These successful mathematical models are discussed by correlating them with the observed characteristics of cellulose.

New and improved method of investigation using thermal tools for characterization of cellulose from eucalypts pulp

International Nuclear Information System (INIS)

Lengowski, Elaine Cristina; Magalhães, Washington Luiz Esteves; Nisgoski, Silvana; Muniz, Graciela Inês Bolzon de; Satyanarayana, Kestur Gundappa; Lazzarotto, Marcelo

2016-01-01

Highlights: • Cellulose was treated to modify its crystallinity. • Cellulose was characterized by X-ray diffraction to evaluate Segal’s index. • TGA and DTA with chemometric tools were used to predict Segal’s index. • MLR model was applied to predict XRD cellulose Segal’s index from TGA curves. • MLR model was applied to predict XRD cellulose Segal’s index from DTA curves. - Abstract: Despite cellulose being the most abundant biopolymer on earth and an important commodity, there is a lack of deeper knowledge about its structure as well as faster and more efficient characterization techniques. This paper presents preparation of nanocellulose from bleached cellulose pulp of Eucalyptus by chemical and mechanical pre-treatments, while the cellulose was given treatment to obtain a great range of crystallinity index. The nanocellulose is characterized by X-ray diffraction to evaluate Segal’s index while chemometric tools by TGA and DTA were used to predict Segal’s index. DTA curves, along with multivariate statistical model, presented better result than TGA. The coefficient of variation and standard error of prediction for the proposed models using external validation samples were in the range of 0.91–0.96 and 4.18–8.71, respectively. These successful mathematical models are discussed by correlating them with the observed characteristics of cellulose.

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

CSIR Research Space (South Africa)

Andrew, JE

2013-08-01

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

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

Science.gov (United States)

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

2012-01-01

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

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

Directory of Open Access Journals (Sweden)

Xueping Song

2016-07-01

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

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

International Nuclear Information System (INIS)

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

2002-01-01

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

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

Directory of Open Access Journals (Sweden)

Roseli Garcia Medeiros

2007-03-01

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

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

Science.gov (United States)

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

2015-01-01

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

Licuri fibers characterization after treatment to produce cellulose nanocrystals

International Nuclear Information System (INIS)

Castro, E.G.; Oliveira, J.C.; Miranda, C.S.; Jose, N.M.

2014-01-01

Cellulose nanocrystals have been widely studied in the materials area due to their high aspect ratio, which is directly related to a good performance as mechanical reinforcement. Obtaining this nanocrystals from commercial bleached pulps, as eucalyptus, or microcrystalline cellulose is well studied. Trying to find new extraction sources, exploring better the huge variety of Brazil’s natural fibers and giving the opportunity of development to small communities, the present work verifies the influence of two bleaching methodologies, sodium hypochlorite or hydrogen peroxide, on licuri fibers. Previous washing and mercerization steps were performed before bleaching. The product of each step was analysed by: DSC, TGA, XRD, SEM and FTIR. The yield of each step was also calculated. (author)

A xylanase-aided enzymatic pretreatment facilitates cellulose nanofibrillation.

Science.gov (United States)

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

2017-11-01

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

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

CSIR Research Space (South Africa)

Andrew, JE

2014-01-01

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

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

OpenAIRE

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

2012-01-01

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

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.

Alkaline Pulping and Bleaching of Acacia auriculiformis Grown in Bangladesh

OpenAIRE

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

2014-01-01

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

Alkali and bleach treatment of the extracted cellulose from pineapple ...

African Journals Online (AJOL)

(FTIR) spectroscopy, Thermogravimetric analysis (TGA) and Differential thermal analysis (DTA). SEM micrographs revealed that alkali treatment removed the impurities in the pineapple leaf fibers and subsequent bleaching further purify the fibers leaving mostly cellulose only while hemicellulose and lignin are removed as ...

Mesta/Kenaf as raw material for Kraft pulping

Energy Technology Data Exchange (ETDEWEB)

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

1980-03-15

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

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

Science.gov (United States)

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

2007-09-01

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

Cellulosic pulps of cereal straws as raw material for the manufacture of ecological packaging

OpenAIRE

Vargas González, Fátima; González, Zoilo; Sánchez, Rafael; Jiménez, Luis; Rodríguez Pascual, Alejandro

2012-01-01

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 viscosit...

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

Directory of Open Access Journals (Sweden)

Elisa Nurnawati

2015-01-01

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

Production of Cellulosic Polymers from Agricultural Wastes

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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.

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

Science.gov (United States)

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

2015-01-01

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

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

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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%.

Properties of cellulose nanocrystals from oil palm trunk isolated by total chlorine free method.

Science.gov (United States)

Lamaming, Junidah; Hashim, Rokiah; Leh, Cheu Peng; Sulaiman, Othman

2017-01-20

Cellulose nanocrystals were isolated from oil palm trunk by total chlorine free method. The samples were either water pre-hydrolyzed or non-water pre-hydrolyzed, subjected to soda pulping, acidified and ozone bleached. Cellulose and cellulose nanocrystal (CNC) physical, chemical, thermal properties, and crystallinity index were investigated by composition analysis, scanning electron microscopy, transmission electron microscopy, fourier transform infrared, thermogravimetric analysis and X-ray diffraction. Water pre-hydrolysis reduced lignin (process compared to non-fibrillated of non-water pre-hydrolyzed cellulose. Water pre-hydrolysis improved final CNC crystallinity (up to 75%) compared to CNC without water pre-hydrolysis crystallinity (69%). Cellulose degradation was found to occur during ozone bleaching stage but CNC showed an increase in crystallinity after acid hydrolysis. Thus, oil palm trunk CNC can be potentially applied in pharmaceutical, food, medical and nanocomposites. Copyright © 2016 Elsevier Ltd. All rights reserved.

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

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

CSIR Research Space (South Africa)

Chunilall, Viren

2006-11-01

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

CP/MAS ¹³C NMR study of pulp hornification using nanocrystalline cellulose as a model system.

Science.gov (United States)

Idström, Alexander; Brelid, Harald; Nydén, Magnus; Nordstierna, Lars

2013-01-30

The hornification process of paper pulp was investigated using solid-state (13)C NMR spectroscopy. Nanocrystalline cellulose was used to serve as a model system of the crystalline parts of the fibrils in pulp fibers. Characterization of the nanocrystalline cellulose dimensions was carried out using scanning electron microscopy. The samples were treated by drying and wetting cycles prior to NMR analysis where the hornification phenomenon was recorded by spectral changes of the cellulose C-4 carbon signals. An increase of the crystalline signal and a decrease of the signals corresponding to the accessible amorphous domains were found for both paper pulp and nanocrystalline cellulose. These spectral changes grew stronger with repeating drying and wetting cycles. The results show that cellulose co-crystallization contribute to hornification. Another conclusion is that the surfaces of higher hydrophobicity in cellulose fibrils have an increased preference for aggregation. Copyright © 2012 Elsevier Ltd. All rights reserved.

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

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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.

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

Science.gov (United States)

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

2015-12-31

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

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

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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.

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

Science.gov (United States)

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

2012-12-01

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

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

Directory of Open Access Journals (Sweden)

Kamila Przybysz Buzała

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

Fabrication of microfibrillated cellulose gel from waste pulp sludge via mild maceration combined with mechanical shearing

Science.gov (United States)

Nusheng Chen; Junyong Zhu; Zhaohui Tong

2016-01-01

This article describes a facile route, which combines mild maceration of waste pulp sludge and a mechanical shearing process, to prepare microfibrillated cellulose (MFC) with a high storage modulus. In the maceration, the mixture of glacial acetic acid and hydrogen peroxide was used to extract cellulose from never-dried waste pulp sludge. Then, two different mechanical...

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...

A novel green approach for the preparation of cellulose nanowhiskers from white coir.

Science.gov (United States)

Nascimento, Diego M; Almeida, Jessica S; Dias, Amanda F; Figueirêdo, Maria Clea B; Morais, João Paulo S; Feitosa, Judith P A; de F Rosa, Morsyleide

2014-09-22

The aim of this work was to optimize the extraction of cellulose nanowhiskers (CNW) from unripe coconut husk fibers (CHF). The CHF was delignified using organosolv process, followed by alkaline bleaching (5% (w/w) H2O2+4% (w/w) NaOH; 50°C, 90 min). The CHF was subsequently hydrolyzed with 30% (v/v) sulfuric acid (60°C, 360 min). The process yielded a partially delignified acetosolv cellulose pulp and acetic black liquor, from which the lignin was recovered. The CNW from the acetosolv pulp exhibited an average length of 172±88 nm and a diameter of 8±3 nm, (aspect ratio of 22±8). The surface charge of the CNW was -33 mV, indicating a stable aqueous colloidal suspension. The nanocrystals presented physical characteristics close to those extracted from cellulose pulp made by CHF chlorine-pulping. This approach offers the additional advantage of extracting the lignin as an alternative to eradication. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

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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.

Evolution of Lignocellulosic Macrocomponents in the Wastewater Streams of a Sulfite Pulp Mill: A Preliminary Biorefining Approach

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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.

The pulping of esparto grass by sodium monosulfite

OpenAIRE

Akchiche, Omar; Messaoud, Boureghda

2007-01-01

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

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

Science.gov (United States)

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

2013-01-01

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

Sodium Hydroxide and Calcium Hydroxide Hybrid Oxygen Bleaching with System

Science.gov (United States)

Doelle, K.; Bajrami, B.

2018-01-01

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

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

Science.gov (United States)

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

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

African Journals Online (AJOL)

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

Kinetics of AOX Formation in Chlorine Dioxide Bleaching of Bagasse Pulp

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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.

Licuri fibers characterization after treatment to produce cellulose nanocrystals; Caracterizacao da fibra de licuri apos tratamento para producao de nanocristais de celulose

Energy Technology Data Exchange (ETDEWEB)

Castro, E.G.; Oliveira, J.C.; Miranda, C.S.; Jose, N.M., E-mail: elyane_casft@msn.com [Universidade Federal da Bahia (GECIM/UFBA), Salvador, BA (Brazil). Programa de Pos-Graduacao em Engenharia Quimica. Grupo de Energia e Ciencias dos Materiais

2014-07-01

Cellulose nanocrystals have been widely studied in the materials area due to their high aspect ratio, which is directly related to a good performance as mechanical reinforcement. Obtaining this nanocrystals from commercial bleached pulps, as eucalyptus, or microcrystalline cellulose is well studied. Trying to find new extraction sources, exploring better the huge variety of Brazil’s natural fibers and giving the opportunity of development to small communities, the present work verifies the influence of two bleaching methodologies, sodium hypochlorite or hydrogen peroxide, on licuri fibers. Previous washing and mercerization steps were performed before bleaching. The product of each step was analysed by: DSC, TGA, XRD, SEM and FTIR. The yield of each step was also calculated. (author)

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

Science.gov (United States)

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

2007-01-01

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

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

Science.gov (United States)

Yanlin Qin; Xueqing Qiu; Junyong Zhu

2016-01-01

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

A comparison of cellulose nanofibrils produced from Cladophora glomerata algae and bleached eucalyptus pulp

Science.gov (United States)

Zhouyang Xiang; Wenhua Gao; Liheng Chen; Wu Lan; Junyong Zhu; Troy Runge

2016-01-01

Cladophora, a fresh-water green macroalgae, has unique cellulose properties and thus may be promising for production of cellulose nanofibrils (CNFs). Cellulose was extracted from Cladophora glomerata and subjected to microfluidization with or without enzymatic hydrolysis pretreatment to produce CNFs. Increasing...

LCA Study for Pilot Scale Production of Cellulose Nano Crystals (CNC) from Wood Pulp

Science.gov (United States)

Hongmei Gu; Richard Reiner; Richard Bergman; Alan Rudie

2015-01-01

Interest in cellulose nanocrystals (CNC)/cellulose nanofibrils (CNF) made from woody biomass has been growing rapidly with close attention from pulp and paper industry, governments, universities, and research institutes. Many new products development with CNCs have been studied intensively. However, little life-cycle analysis (LCA) has been conducted for the...

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

OpenAIRE

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

2010-01-01

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

Cellulose fibril aggregation studies of eucalyptus dissolving pulps using atomic force microscopy

CSIR Research Space (South Africa)

Chunilall, Viren

2006-11-01

Full Text Available STUDIES OF Eucalyptus DISSOLVING PULPS USING ATOMIC FORCE MICROSCOPY V. Chunilall1, J.Wesley-Smith2, T. Bush1 1CSIR, Forestry and Forest Product Research Centre, P.O. Box 17001, Congella, 4013, South Africa. 2Electron Microscope Unit, University of Kwa... pulp using atomic force microscopy (AFM) have reported increased cellulose fibril aggregation during processing, and a concomitant decrease in surface area available for chemical reaction1,2. These findings were subsequently confirmed...

Application of TAED/H2O2 system for low temperature bleaching of crude cellulose extracted from jute fiber

Science.gov (United States)

Wen, Zuoqiang; Zou, Linbo; Wang, Weiming

2018-03-01

Tetraacetylethylenediamine (TAED) activated hydrogen peroxide system had been applied for bleaching of crude cellulose extracted from jute fiber. Comparing with conventional hydrogen peroxide bleaching system, those results showed that bleaching temperature and time could be effectively reduced, and a preferable whiteness could be produced under faint alkaline condition. And the optimum conditions for activated bleaching system could be summarized as molar ratio of H2O2/TAED 1:0.7, pH 8, pure hydrogen peroxide 0.09 mol/L, temperature 70 °C and time 60min.

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

Science.gov (United States)

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

2017-07-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2001-03-01

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

The Influence of Nano-Fibrillated Cellulose as a Coating Component in Paper Coating

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Yaxi Xu

2016-03-01

Full Text Available This work investigates nano-fibrillated cellulose (NFC as a component in mineral pigment paper coating. In this work, bleached Eucalyptus pulp was pretreated by TEMPO (2,2,6,6-tetramethyl-1-piperdinyloxy-mediated oxidation. The oxidized pulp was then isolated to obtain NFC by sonication. Aqueous coating colors consisting of calcium carbonate, clay, carboxylated butadiene-styrene latex, additives, and NFC were prepared. The rheology of the coating colors and the surface properties of paper coated with NFC containing coating colors were determined. The rheological properties allowed NFC to be used in small amounts under laboratory conditions. Nano-fibrillated cellulose was found to improve the surface strength and smoothness of the coated paper. The water resistance of coated paper, on the other hand, decreased because of the hydrophilicity of NFC.

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

Science.gov (United States)

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

2014-02-01

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

Effect of pH on production of xylanase by Trichoderma reesei on xylan- and cellulose-based media

Energy Technology Data Exchange (ETDEWEB)

Bailey, M.J. (VTT, Biotechnical Lab., Espoo (Finland)); Buchert, J. (VTT, Biotechnical Lab., Espoo (Finland)); Viikari, L. (VTT, Biotechnical Lab., Espoo (Finland))

1993-11-01

Trichoderma reesei VTT-D-86271 (Rut C-30) was cultivated on media based on cellulose and xylan as the main carbon source in fermentors with different pH minimum controls. Production of xylanase was favoured by a rather high pH minimum control between 6.0 and 7.0 on both cellulose- and xylan-based media. Although xylanase was produced efficiently on cellulose as well as on xylan as the carbon source, significant production of cellulase was observed only on the cellulose-based medium and best production was at lower pH (4.0 minimum). Production of xylanase at pH 7.0 was shown to be dependent on the nature of the xylan in the cultivation medium but was independent of other organic components. Best production of xylanase was observed on insoluble, unsubstituted beech xylan at pH 7.0. Similar results were obtained in laboratory and pilot (200-1) fermentors. Downstream processing of the xylanase-rich, low-cellulase culture filtrate presented no technical problems despite apparent autolysis of the fungus at the high pH. Enzyme produced in the 200-1 pilot fermentor was shown to be suitable for use in enzyme-aided bleaching of kraft pulp. Due to the high xylanase/cellulase ratio of enzyme activities in the culture filtrate, pretreatment for removal of cellulase activity prior to pulp bleaching was unnecessary. (orig.)

Alkaline pulping of some eucalypts from Sudan.

Science.gov (United States)

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

2006-03-01

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

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)

Effect of Mixing Temperature of CMP Pulp and Cellulose Nanofiber on Paper Properties

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Sahba Alinia

2013-06-01

Full Text Available Several processing parameters affect the function of cellulose nanofiber as an environmentally friend cellulosic reinforcer. One of the potential parameters can be the mixing temperature of pulp and cellulose nanofiber that has been investigated in this study. In order to study the influence of this parameter, mixing drainage velocity and the air permeability and strength properties of resulting paper were measured. A mixture of chemi-mechanical pulp suspensions (with concentration of 0.2 wt% and freeness of 250 ml, CSF containing 5 wt% cellulose nanofiber were prepared. This mixture was then stirred at 25, 50, and 70 ◦C using a magnetic stirrer for 1 hour followed by draining using vacuum filtration to make wet handsheet. The wet handsheet was first pressed, and then dried in oven at 100 ◦C for 24 hours. The test’ results showed that the increase of mixing temperature led to decreasing drainage time and air permeability. The strength properties of paper reinforced by nanofibers were positively affected by mixing temperature (i.e. the more mixing temperature, the higher strength. The data of tensile strength index was considerably increased. The tear strength of paper increased approximately by 200% over rising mixing temperature.

Gamma ray induced chromophore modification of softwood thermomechanical pulp

International Nuclear Information System (INIS)

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

1992-01-01

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

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

Science.gov (United States)

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

2010-01-01

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

Cellulose, hemicelluloses, lignin and ash content of some organic materials and their suitability for use as paper pulp supplements.

Science.gov (United States)

Ververis, C; Georghiou, K; Danielidis, D; Hatzinikolaou, D G; Santas, P; Santas, R; Corleti, V

2007-01-01

Freshwater algal biomass and orange and lemon peels were assessed as tissue paper pulp supplements. Cellulose and hemicellulose contents of algal biomass were 7.1% and 16.3%, respectively, whereas for citrus peels cellulose content ranged from 12.7% to 13.6% and hemicellulose from 5.3% to 6.1%. For all materials, lignin and ash content was 2% or lower, rendering them suitable for use as paper pulp supplements. The addition of algal biomass to paper pulp increased its mechanical strength significantly. However, brightness was adversely affected by chlorophyll. The addition of citrus peels in paper pulp had no effect on breaking length, increased bursting strength and decreased tearing resistance. Brightness was negatively affected at proportions of 10%, because citrus peel particles behave as coloured pigments. The cost of both materials is about 45% lower than that of conventional pulp, resulting in a 0.9-4.5% reduction in final paper price upon their addition to the pulp.

Potential of hot water extraction of birch wood to produce high-purity dissolving pulp after alkaline pulping.

Science.gov (United States)

Borrega, Marc; Tolonen, Lasse K; Bardot, Fanny; Testova, Lidia; Sixta, Herbert

2013-05-01

The potential of hot water extraction of birch wood to produce highly purified dissolving pulp in a subsequent soda-anthraquinone pulping process was evaluated. After intermediate extraction intensities, pulps with low xylan content (3-5%) and high cellulose yield were successfully produced. Increasing extraction intensity further decreased the xylan content in pulp. However, below a xylan content of 3%, the cellulose yield dramatically decreased. This is believed to be due to cleavage of glycosidic bonds in cellulose during severe hot water extractions, followed by peeling reactions during alkaline pulping. Addition of sodium borohydride as well as increased anthraquinone concentration in the pulping liquor increased the cellulose yield, but had no clear effects on pulp purity and viscosity. The low intrinsic viscosity of pulps produced after severe extraction intensities and soda-anthraquinone pulping corresponded to the viscosity at the leveling-off degree of polymerization, suggesting that nearly all amorphous cellulose had been degraded. Copyright © 2012 Elsevier Ltd. All rights reserved.

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

Directory of Open Access Journals (Sweden)

Esat Gümüşkaya

2003-04-01

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

Isolation of cellulose fibers from kenaf using electron beam

International Nuclear Information System (INIS)

Shin, Hye Kyoung; Pyo Jeun, Joon; Bin Kim, Hyun; Hyun Kang, Phil

2012-01-01

Cellulose fibers were isolated from a kenaf bast fiber using a electron beam irradiation (EBI) treatment. The methods of isolation were based on a hot water treatment after EBI and two-step bleaching processes. FT-IR spectroscopy demonstrated that the content of lignin and hemicellulose in the bleached cellulose fibers treated with various EBI doses decreased with increasing doses of EBI. Specifically, the lignin in the bleached cellulose fibers treated at 300 kGy, was almost completely removed. Moreover, XRD analyses showed that the bleached cellulose fibers treated at 300 kGy presented the highest crystallinity of all the samples treated with EBI. Finally, the morphology of the bleached fiber was characterized by SEM imagery, and the studies showed that the separated degree of bleached cellulose fibers treated with various EBI doses increased with an increase of EBI dose, and the bleached cellulose fibers obtained by EBI treatment at 300 kGy was separated more uniformly than the bleached cellulose fiber obtained by alkali cooking with non-irradiated kenaf fiber. - Highlights: ► This study was to provide a progressive and convenient cellulose isolation process. ► Using an electron beam irradiation, we can obtain cellulose fibers using only water without chemicals during cooking process. ► We think that this cellulose isolation method will have an effect on enormous environmental and economic benefits.

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

OpenAIRE

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

2010-01-01

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

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. Copyright © 2012 Elsevier Ltd. All rights reserved.

The effect of pulping concentration treatment on the properties of microcrystalline cellulose powder obtained from waste paper.

Science.gov (United States)

Okwonna, Okumneme O

2013-10-15

Microcrystalline cellulose (MCC) powder was isolated from three grades of waste paper: book, Groundwood/Newsprint and paperboard, through the processes of pulping and hydrolysis. Pulping treatment on these grades of waste paper was done using varying concentrations of caustic soda. Effects of the concentration of the pulping medium on the thermal and kinetic properties were investigated. Also determined were the effects of this on the physico-chemical properties. The chemical structure was characterized using an infrared spectroscopy (FTIR). Results showed these properties to be affected by the concentration of the pulping medium. Copyright © 2013 Elsevier Ltd. All rights reserved.

OZONE BLEACHING AT NEUTRAL PH – A NEW CONCEPT

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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.

Physicochemical properties of prepared ion-exchangers from cellulose incorporated with different functional groups

International Nuclear Information System (INIS)

Nada, A.M.A.; Adel, A.M.

2005-01-01

Bagasse raw material and bleached bagasse pulp was used to prepare carbamoyl ethyl and Carboxylated cellulose ion exchangers. The effect of presence of lignin in the bagasse on the properties of the produced resin was estimated. The effect of crosslinking on the properties of the carbamoyl ethyl and carboxyl cellulose was investigated. The molecular structure of the produced resin is followed by using infrared spectroscopy. A new bands was seen at wavenumber 2152 cm-1 and a shoulder at 3140 cm-1 which are characteristic to the cyano group in cyanoethylated cellulose and to amino group in the carbamoyl ethyl cellulose. Also, a band was formed at 1715 cm-1 which formed by hydrolysis of cyanoethyl or carbamoyl ethyl cellulose and was characteristic to carboxyl group. A thermal gravimetric of the produced resin was investigated. The cyano group and carbamoyl group increases the resistance of cellulose toward thermal treatment. The efficiency of the produced resin toward metal ion uptake (Cu, Ni and Cr) from solution was studied

Cellulose fibers obtained by organosolv process from date palm rachis (Phoenix dactylifera L.)

International Nuclear Information System (INIS)

Ammar, H; Abid, M; Abid, S

2012-01-01

In this preliminary study, the chemical composition of Tunisian DPR was established and discussed. The main characteristic of this agri-residue was its high lignin content in comparison with that of alfa plant. CIMV process was used to selectively separate cellulose fibres, hemicelluloses and lignin at atmospheric pressure. The obtained unbleached pulp was analysed in accordance with Kappa index and degree of polymerisation and then bleached by treating successively with peroxyacids and hydrogen peroxide in basic media.

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

Science.gov (United States)

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

2018-06-11

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

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

OpenAIRE

Qiang Zhao; Junwen Pu; Shulei Mao; Guibo Qi

2010-01-01

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

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

Directory of Open Access Journals (Sweden)

Lang-Dong Lin

2015-04-01

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

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

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Gustavo Ventorim

2010-08-01

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

The impact of kappa number composition on eucalyptus kraft pulp bleachability

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M. M. Costa

2007-03-01

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

40 CFR 63.445 - Standards for the bleaching system.

Science.gov (United States)

2010-07-01

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

Isolation of cellulose microfibrils - An enzymatic approach

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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.

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

Directory of Open Access Journals (Sweden)

Renata Suellen Galvão da Silva-Costa

2018-06-01

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

Chemi-thermomechanical pulping of para rubber waste wood

Energy Technology Data Exchange (ETDEWEB)

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

1981-01-01

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

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

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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.

Detoxification of kraft pulp ECF bleaching effluents by catalytic hydrotreatment.

Science.gov (United States)

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

2007-02-01

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

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...

PEMUTIHAN PULP DENGAN HIDROGEN PEROKSIDA

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Ahmad M. Fuadi

2012-01-01

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

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

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Alexsandra Valéria Sousa Costa de Lima

2016-12-01

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

Potassium hydroxide pulping of rice straw in biorefinery initiatives.

Science.gov (United States)

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

2016-11-01

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

Method and apparatus for assaying wood pulp fibers

Science.gov (United States)

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

2009-05-26

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

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

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maryam allahdadi

2017-05-01

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

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

African Journals Online (AJOL)

2017-12-05

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

ON THE RECOVERY OF HEMICELLULOSE BEFORE KRAFT PULPING

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Carlos Vila,

2012-07-01

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

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

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Claudio Salazar

2012-05-01

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

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.

Effects of bagasse microfibrillated cellulose and cationic polyacrylamide on key properties of bagasse paper.

Science.gov (United States)

Djafari Petroudy, Seyed Rahman; Syverud, Kristin; Chinga-Carrasco, Gary; Ghasemain, Ali; Resalati, Hossein

2014-01-01

This study explores the benefits of using bagasse microfibrillated cellulose (MFC) in bagasse paper. Two different types of MFC were produced from DED bleached soda bagasse pulp. The MFC was added to soda bagasse pulp furnishes in different amounts. Cationic polyacrylamide (C-PAM) was selected as retention aid. The results show that addition of MFC increased the strength of paper as expected. Interestingly, 1% MFC in combination with 0.1% C-PAM yielded similar drainage time as the reference pulp, which did not contain MFC. In addition, the samples containing 1% MFC and 0.1% C-PAM yielded (i) a significant increment of the tensile index, (ii) a minor decrease of opacity and (iii) preserved Gurley porosity. Hence, this study proves that small fractions of MFC in combination with adequate retention aids can have positive effects with respect to paper properties, which is most interesting from an industrial point of view. Copyright © 2013 Elsevier Ltd. All rights reserved.

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.

Methods of pretreating comminuted cellulosic material with carbonate-containing solutions

Energy Technology Data Exchange (ETDEWEB)

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.

Evaluation of bleachability on pine and eucalyptus kraft pulps

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Marcela Freitas Andrade

2013-09-01

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

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.

Thermally Stable Cellulose Nanocrystals toward High-Performance 2D and 3D Nanostructures.

Science.gov (United States)

Jia, Chao; Bian, Huiyang; Gao, Tingting; Jiang, Feng; Kierzewski, Iain Michael; Wang, Yilin; Yao, Yonggang; Chen, Liheng; Shao, Ziqiang; Zhu, J Y; Hu, Liangbing

2017-08-30

Cellulose nanomaterials have attracted much attention in a broad range of fields such as flexible electronics, tissue engineering, and 3D printing for their excellent mechanical strength and intriguing optical properties. Economic, sustainable, and eco-friendly production of cellulose nanomaterials with high thermal stability, however, remains a tremendous challenge. Here versatile cellulose nanocrystals (DM-OA-CNCs) are prepared through fully recyclable oxalic acid (OA) hydrolysis along with disk-milling (DM) pretreatment of bleached kraft eucalyptus pulp. Compared with the commonly used cellulose nanocrystals from sulfuric acid hydrolysis, DM-OA-CNCs show several advantages including large aspect ratio, carboxylated surface, and excellent thermal stability along with high yield. We also successfully demonstrate the fabrication of high-performance films and 3D-printed patterns using DM-OA-CNCs. The high-performance films with high transparency, ultralow haze, and excellent thermal stability have the great potential for applications in flexible electronic devices. The 3D-printed patterns with porous structures can be potentially applied in the field of tissue engineering as scaffolds.

Tooth Whitening And Temperature Rise With Two Bleaching Activation Methods

International Nuclear Information System (INIS)

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

2009-01-01

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

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

Science.gov (United States)

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

2008-11-01

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

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

Science.gov (United States)

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

2018-04-01

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

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.

PRODUCTION OF PRINTING AND WRITING PAPER GRADE PULP FROM ELEPHANT GRASS

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Marcela Freitas Andrade

2016-09-01

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

Holdup time measurement by radioactive tracers in pulp production

International Nuclear Information System (INIS)

Roetzer, H.; Donhoffer, D.

1988-12-01

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

INVESTIGATION OF AQUEOUS BIPHASIC SYSTEMS FOR THE SEPARATIONS OF LIGNINS FROM CELLULOSE IN THE PAPER PULPING PROCESS. (R826732)

Science.gov (United States)

In efforts to apply a polymer-based aqueous biphasic system (ABS) extraction to the paper pulping process, the study of the distribution of various lignin and cellulosic fractions in ABS and the effects of temperature on system composition and solute partitioning have been inv...

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

Science.gov (United States)

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

2014-09-01

The work in this paper was planned with the aim of extracting the cellulosic component of palm tree waste and functionalizing this cellulose through graft copolymerization with acrylic acid. The cellulose extraction included hot alkali treatment with aqueous sodium hydroxide to remove the non-cellulosic binding materials. The alkali treatment was followed by an oxidative bleaching using peracid/hydrogen peroxide mixture with the aim of removing the rest of non-cellulosic materials to improve the fiber hydrophilicity and accessibility towards further grafting reaction. Optimum conditions for cellulose extraction are boiling in 5% (W/V) NaOH in a material to liquor ratio of 1:20 for 1 h then bleaching with 60 ml/l bleaching mixture at initial pH value of 6.5 for 30 min. The pH of the bleaching medium is turned to the alkaline range 11 and bleaching continues for extra 30 min. Graft copolymerization reaction was initiated by potassium bromate/thiourea dioxide redox system. Optimum conditions for grafting are 30 mmol of potassium bromate, 30 mmol of thiourea dioxide and 150 g of acrylic acid (each per 100 g of cellulose). The polymerization reaction was carried out for 120 min at 50°C using a material to liquor ratio of 1:20. Copyright © 2014 Elsevier B.V. All rights reserved.

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

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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.

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

OpenAIRE

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

2002-01-01

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

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

INFLUENCE OF CELLULOSE POLYMERIZATION DEGREE AND CRYSTALLINITY ON KINETICS OF CELLULOSE DEGRADATION

OpenAIRE

Edita Jasiukaitytė-Grojzdek,; Matjaž Kunaver,; Ida Poljanšek

2012-01-01

Cellulose was treated in ethylene glycol with p-toluene sulfonic acid monohydrate as a catalyst at different temperatures. At the highest treatment temperature (150 °C) liquefaction of wood pulp cellulose was achieved and was dependant on cellulose polymerization degree (DP). Furthermore, the rate of amorphous cellulose weight loss was found to increase with cellulose degree of polymerization, while the rate of crystalline cellulose weight loss was reciprocal to the size of the crystallites. ...

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

International Nuclear Information System (INIS)

Arif, S.; Kautek, W.

2013-01-01

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.

Extraction and characterisation of cellulose nanocrystals from pineapple peel

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Ana Raquel Madureira

2018-04-01

Full Text Available The potential of pineapple peel as a source of cellulose nanocrystals was evaluated. Peels skin from fresh-cut fruit was used as raw material. These residues were purified to remove pigments, lipids and hemicellulose, and a bleaching process for delignification was carried out for 4-6 h. All resulting products were characterised for their lignin, hemicellulose, cellulose and ash contents using standard techniques. Dry matter at the end was low (ca. 50% compared with the raw material (ca. 90%. The process applied resulted in ca. 20% (m/m of purified cellulose (ca. 80% purity, with ineligible levels of lignin and hemicellulose present, especially when using 6h of bleaching. The purified cellulose was subject to acid hydrolysis for nanocrystal extraction with two testing times, 30 and 60 minutes. These cellulose nanocrystals had small sizes (< 1000 nm, with high variability and negative zeta potential values. The time of extraction did not affect the nanocrystals’ chemical and physical properties. The use of 6 h of bleaching treatment during purification was shown to be more effective than 4 h. Pineapple peel was demonstrated to be a good source of cellulose for the production of cellulose nanocrystals.

Facile Synthesis of Highly Hydrophobic Cellulose Nanoparticles through Post-Esterification Microfluidization

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Chunxiang Lin

2018-04-01

Full Text Available A post-esterification with a high degree of substitution (hDS mechanical treatment (Pe(hDSM approach was used for the production of highly hydrophobic cellulose nanoparticles (CNPs. The process has the advantages of substantially reducing the mechanical energy input for the production of CNPs and avoiding CNP aggregation through drying or solvent exchange. A conventional esterification reaction was carried out using a mixture of acetic anhydride, acetic acid, and concentrated sulfuric acid, but at temperatures of 60–85 °C. The successful hDS esterification of bleached eucalyptus kraft pulp fibers was confirmed by a variety of techniques, such as Fourier transform infrared (FTIR, solid state 13C NMR, X-ray photoelectron spectroscopy (XPS, elemental analyses, and X-ray diffraction (XRD. The CNP morphology and size were examined by atomic force microscopy (AFM as well as dynamic light scattering. The hydrophobicity of the PeM-CNP was confirmed by the redispersion of freeze-dried CNPs into organic solvents and water contact-angle measurements. Finally, the partial conversion of cellulose I to cellulose II through esterification improved PeM-CNP thermal stability.

Irradiation effects in wood and cellulose

International Nuclear Information System (INIS)

McLaren, K.G.

1976-01-01

For cellulosic materials the predominant effect of high energy radiation is depolymerisation and degradation by chain scission, although there is some evidence that crosslinking or cellulose stabilisation can occur under certain conditions. When the cellulose is in the form of a natural product such as wood, where it is intimately associated with other polysaccharides, lignins, resins and gums, the effects of radiation can be significantly modified. Examination of cellulose produced by chemical pulping treatment of wood which had been previously given small doses of radiation, showed significant differences in the extent of cellulose depolymerisation with different wood species. The relevance of this work to the paper pulp industry will also be discussed. (author)

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

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Gabriella eTeti

2015-10-01

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

Effect of Urea Addition on Soda Pulping of Oak Wood

OpenAIRE

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

2008-01-01

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

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

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Sreekumar Janardhnan

2011-04-01

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

X-ray Studies of Regenerated Cellulose Fibers Wet Spun from Cotton Linter Pulp in NaOH/Thiourea Aqueous Solutions

Energy Technology Data Exchange (ETDEWEB)

Chen,X.; Burger, C.; Fang, D.; Ruan, D.; Zhang, L.; Hsiao, B.; Chu, B.

2006-01-01

Regenerated cellulose fibers were fabricated by dissolution of cotton linter pulp in NaOH (9.5 wt%) and thiourea (4.5 wt%) aqueous solution followed by wet-spinning and multi-roller drawing. The multi-roller drawing process involved three stages: coagulation (I), coagulation (II) and post-treatment (III). The crystalline structure and morphology of regenerated cellulose fiber was investigated by synchrotron wide-angle X-ray diffraction (WAXD) and small-angle X-ray scattering (SAXS) techniques. Results indicated that only the cellulose II crystal structure was found in regenerated cellulose fibers, proving that the cellulose crystals were completely transformed from cellulose I to II structure during spinning from NaOH/thiourea aqueous solution. The crystallinity, orientation and crystal size at each stage were determined from the WAXD analysis. Drawing of cellulose fibers in the coagulation (II) bath (H{sub 2}SO{sub 4}/H{sub 2}O) was found to generate higher orientation and crystallinity than drawing in the post-treatment (III). Although the post-treatment process also increased crystal orientation, it led to a decrease in crystallinity with notable reduction in the anisotropic fraction. Compared with commercial rayon fibers fabricated by the viscose process, the regenerated cellulose fibers exhibited higher crystallinity but lower crystal orientation. SAXS results revealed a clear scattering maximum along the meridian direction in all regenerated cellulose fibers, indicating the formation of lamellar structure during spinning.

ISOLATION AND CHARACTERIZATION OF NANOFIBRILLATED CELLULOSE FROM OAT HULLS

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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.

Effect of organosolv and soda pulping processes on the metals content of non-woody pulps.

Science.gov (United States)

González, M; Cantón, L; Rodríguez, A; Labidi, J

2008-09-01

In this work the effect of different pulping processes (ethyleneglycol, diethyleneglycol, ethanolamine and soda) of tow abounded raw materials (empty fruit bunches - EFB and rice straw) on the ash, silicates and metals (Fe, Zn, Cu, Pb, Mn, Ni and Cd) content of the obtained pulps have been studied. Results showed that pulps obtained by diethyleneglycol pulping process presented lower metals content (756 microg/g and 501 microg/g for EFB and rice straw pulp, respectively) than soda pulps (984 microg/g and 889 microg/g). Ethanolamine pulps presented values of holocellulose (74% and 77% for EFB and rice straw pulp, respectively), alpha-cellulose (74% and 69%), kappa number (18.7 and 18.5) and viscosity (612 and 90 6ml/g) similar to those of soda pulp, and lower lignin contents (11% and 12%).

Pulping and paper properties of Palmyra palm fruit fibers

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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.

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. Copyright © 2012 Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

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

2008-11-01

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

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

Science.gov (United States)

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

2013-11-01

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

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

International Nuclear Information System (INIS)

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

1999-01-01

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

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)

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

Science.gov (United States)

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

2005-01-01

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

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

Science.gov (United States)

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

1999-04-01

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

Radiation -adsorption treatment of pesticides by using wood pulp and bagasse pulp

International Nuclear Information System (INIS)

Abd El-Aal, S.E.; Sokker, S.S.; Dessooki, A.M.

2005-01-01

Alkaline pulping of pulp wood and bagasse using sodium hydroxide resulted in the reduction of lignin from the wood and bagasse fibers and consequently increase adsorption of the pesticide pollutants to these fibers. Three different types of pesticides were used in this study namely, metalaxyl, dicloran and arelon. which were irradiated at a dose of 4 kGy before adsorption treatment.The results show that moderate adsorption was observed for all pesticides when adsorption was carried out without alkaline pulping and irradiation. This is due to the presence of lignin which retard the adsorption process. Batch sorption experiments at different pH values (3, 7, 9) for the retention of these pesticides by pulp wood and pulp bagasse fibers indicated that sorption is governed by the interaction of the ionized form of these compounds with the polyhydroxyl structure of cellulose. The study shows that alkaline pulping of pulpwood and bagasse improves its ability towards adsorption of the radiation degraded pesticide molecules

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).

Radiation application for paper preservation: gamma irradiation at Eucalyptus pulp sheets

International Nuclear Information System (INIS)

Borrely, Sueli Ivone; Barbosa, Patricia S.M.; D'Almeida, Maria Luiza O.

2009-01-01

Ionizing radiation has been proposed in order to protect information and books that may be lost due to fungi and or insects infestation. In general restaurators are very worried about the maintenance of original properties of items to be treated. The selected technology must consider two points: type of biological contamination and contamination control. Fungi is one of the principal organism which grows well on papers. Once this infestation is installed on the paper it will signify spots, resistance loses and deterioration. The organisms feces introduces enzymes, organic acids and pigments to the contaminated material. Ionizing radiation from gamma sources were applied at laboratory sheets manufactured with commercial cellulose pulp. The subject of this present paper was to investigate the ideal radiation dose that is safe for keeping the paper quality. Laboratory sheets (75 g/m 2 ) were prepared in a TAPPI sheet former. Bleached sulphate Eucalyptus pulp, refined in laboratory PFI mill to 31 deg SR, was the raw material. The formed sheets were irradiated at IPEN's 60 Co Gammacell with 3 kGy up to 25 kGy. No significant changes were detected in paper samples irradiated up to 9 kGy. This is the radiation dose to be suggested. During irradiation the applied dose rate was 0.817 Gy/s. (author)

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

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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.

PULP OBTAINING METHOD FOR PACKAGE PRODUCTION

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V. V. Kuzmich

2015-01-01

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

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.

Scale up of ethanol production using pulp mill wastewater sludge by cellulase and saccharomyces cerevisiae

International Nuclear Information System (INIS)

Kunchada Sangasintu; Petchporn Chawakitchareon

2010-01-01

This study aimed to evaluate the potential use of pulp mill wastewater sludge as substrate in ethanol production. The simultaneous saccharification and fermentation process was conducted by using Saccharomyces cerevisiae TISTR 5339 under optimum proportion of cellulase and pulp mill wastewater sludge. The ethanol production from cellulosic materials in simultaneous saccharification and fermentation needs cooperation between cellulase and yeast. The cellulase hydrolyzes cellulose to sugar while yeast utilizes sugar to produce ethanol. The pulp mill wastewater sludge has an average content of 73.3 % hemi cellulose, 67.1 % alpha cellulose, 4.7 % beta cellulose and 1.4 % gamma cellulose. The experimental results indicated that the volume of the ethanol tend to increase with time, providing the maximum ethanol yield of 0.69 g/g on the 7"t"h day, the last day of the experiment. The ethanol production was scaled up in 5 L fermentor under optimum proportion and increased the fermentation period. It was found that the ethanol production gave the maximum ethanol yield of 1.14 g/g on the 9"t"h day of the totally 13 days experimentation. These results showed that the cellulose from pulp mill wastewater sludge was as effective substrate for ethanol production and alternative energy for the future. (author)

Water requirements of the pulp and paper industry

Science.gov (United States)

Mussey, Orville D.

1955-01-01

Water, of varied qualities, is used for several purposes in the manufacture of pulp and paper, as a vehicle for transporting the constituents of paper in the paper machines; as process water for cooking wood chips to make pulp; as a medium for heat transfer; and for washing the pulpwood, the woodpulp, and the machines that handle the pulp. About 3,200 million gallons of water was withdrawn from surface- and ground-water sources each day during 1950 for the use of the pulp and paper industry. This is about 4 percent of the total estimated industrial withdrawal of water in the Nation The paper industry in the United States has been growing at a rapid rate. It has increased about tenfold in the last 50 years and has doubled every 15 years. The 1950 production of paper was about 24 million tons, which amounts to about 85 percent of the domestic consumption. In 1950, the pulp mills of the country produced more than 14 million tons of woodpulp, which supplied about 85 percent of the demand by the paper mills and other industries. The remainder of the fiber for paper manufacture was obtained from imported woodpulp, from reclaimed wastepaper, and from other fibers including rags and straw. The nationwide paper consumption for 1955 has been estimated at 31,700,000 tons. Woodpulp is classified according to the process by which it is made. Every woodpulp has characteristics that are carried over into the many and diverse grades of paper. Groundwood pulp is manufactured by simply grinding up wood and refining the resulting product. Soda, sulfite, and sulfate pulps are manufactured by chemically breaking down the lignin that cements the cellulose of the wood together and removing, cleaning, and sometimes bleaching the resulting fibers. Some woodpulp is produced by other methods. Sulfate-pulp mills are increasing in number and in rated daily capacity and are manufacturing more than half of the present domestic production of woodpulp. Most of the newer and larger woodpulp mills

BLEACHING NEPTUNE BALLS

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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.

Overview of Cellulose Nanomaterials, Their Capabilities and Applications

Science.gov (United States)

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

2016-01-01

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...

Influence of alkaline hydrogen peroxide pre-hydrolysis on the isolation of microcrystalline cellulose from oil palm fronds.

Science.gov (United States)

Owolabi, Abdulwahab F; Haafiz, M K Mohamad; Hossain, Md Sohrab; Hussin, M Hazwan; Fazita, M R Nurul

2017-02-01

In the present study, microcrystalline cellulose (MCC) was isolated from oil palm fronds (OPF) using chemo-mechanical process. Wherein, alkaline hydrogen peroxide (AHP) was utilized to extract OPF fibre at different AHP concentrations. The OPF pulp fibre was then bleached with acidified sodium chlorite solution followed by the acid hydrolysis using hydrochloric acid. Several analytical methods were conducted to determine the influence of AHP concentration on thermal properties, morphological properties, microscopic and crystalline behaviour of isolated MCC. Results showed that the MCC extracted from OPF fibres had fibre diameters of 7.55-9.11nm. X-ray diffraction (XRD) analyses revealed that the obtained microcrystalline fibre had both celluloses I and cellulose II polymorphs structure, depending on the AHP concentrations. The Fourier transmission infrared (FTIR) analyses showed that the AHP pre-hydrolysis was successfully removed hemicelluloses and lignin from the OPF fibre. The crystallinity of the MCC was increased with the AHP concentrations. The degradation temperature of MCC was about 300°C. The finding of the present study showed that pre-treatment process potentially influenced the quality of the isolation of MCC from oil palm fronds. Copyright © 2016 Elsevier B.V. All rights reserved.

Integrated chemical plants at the pulp mill

Energy Technology Data Exchange (ETDEWEB)

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

1995-12-31

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

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

Science.gov (United States)

Christopher Litvay; Alan Rudie; Peter Hart

2003-01-01

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

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

Science.gov (United States)

Khristova, P; Kordsachia, O; Khider, T

2005-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

Panda, A.

1980-03-15

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

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

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.

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

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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.

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

International Nuclear Information System (INIS)

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

1976-01-01

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

Rice straw pulp obtained by using various methods.

Science.gov (United States)

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

2008-05-01

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

Effect of the chemical treatments on the characteristics of natural cellulose

International Nuclear Information System (INIS)

Sosiati, H.; Muhaimin, M.; Abdilah, P.; Wijayanti, D. A.; Harsojo; Triyana, K.

2014-01-01

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 2 O 2 and H 2 SO 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

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.

Nanofibrillated cellulose (NFC) as a potential reinforcement for high performance cement mortar composites

OpenAIRE

Ardanuy Raso, Mònica; Claramunt Blanes, Josep; Arévalo Peces, Raquel; Parés Sabatés, Ferran; Aracri, Elisabetta; Vidal Lluciá, Teresa

2012-01-01

In this work, nanofibrillated cellulose (NFC) has been evaluated as a potential reinforcement for cement mortar composites. Two types of vegetable fibres with different composition and properties (cellulose content and microfibrillar angle), sisal, and cotton linters pulps, were initially characterized in order to assess their reinforcement capability. Sisal pulp was found to be most suitable as reinforcement for their brittle cementitious matrix. Nanofibrillated cellulose was produced by th...

Lignocellulose Biomass: Constitutive Polymers. Biological Processes of Lignin Degradation; Biomasa lignocelulosica, polimeros constitutivos. Procesos biologicos de degradacion de la lignina

Energy Technology Data Exchange (ETDEWEB)

Martin, C; Manzanares, P

1994-07-01

The structure of the lignocellulosic materials and the chemical composition of their main constitutive polymers, cellulose, hemicelluloses and lignin are described. The most promising transformation processes according to the type of biomass considered: hardwood, softwood an herbaceous and the perspectives of biotechnological processes for bio pulping, bio bleaching and effluents decolorisation in the paper pulp industry are also discussed. (Author) 7 refs.

Lignocellulose Biomass: Constitutive Polymers. Biological Processes of Lignin Degradation

International Nuclear Information System (INIS)

Martin, C.; Manzanares, P.

1994-01-01

The structure of the lignocellulosic materials and the chemical composition of their main constitutive polymers, cellulose, hemicelluloses and lignin are described. The most promising transformation processes according to the type of biomass considered: hardwood, softwood an herbaceous and the perspectives of biotechnological processes for bio pulping, bio bleaching and effluents decolorisation in the paper pulp industry are also discussed. (Author) 7 refs

Improvement in Dissolution of Cotton Pulp with Ionic liquid by the Electron Beam Treatment

International Nuclear Information System (INIS)

Lee, Won Sil; Jung, Wong Gi; Sung, Yong Joo

2013-01-01

Electron beam treatment was applied for improving dissolution of cotton pulp with ionic liquids. Two ionic liquids, 1-allyl-3-methylimidazolium chloride ([Amim]Cl]: AC) and 1,3-dimethylimidzolium methlphosphite ([Dmim][(MeO)(H)PO2]: Me) were used for this experiment. Treatment with electron beams up to dose of 400 kGy resulted in the increase of hot water extract and alkali extract of cotton pulp and the great reduction in the molecular weight of cellulose. For the dissolution of cotton pulp with two ionic liquids, the electron beam treated samples showed faster dissolution. The dissolved cellulose with Me ionic liquid were regenerated with Acetonitrile and the structure of regenerated cellulose showed distinct difference depending on the electron beam treatment. Those results provide the electron beam pre-treatment could be applied as an energy efficient and environmentally benign method to increase the dissolution of cotton pulp with ionic liquids

SURFACE MODIFICATION OF SUGARCANE BAGASSE CELLULOSE AND ITS EFFECT ON MECHANICAL AND WATER ABSORPTION PROPERTIES OF SUGARCANE BAGASSE CELLULOSE/ HDPE COMPOSITES

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Daniella Regina Mulinari

2010-05-01

Full Text Available Cellulose fibres from sugarcane bagasse were bleached and modified by zirconium oxychloride in order to improve the mechanical properties of composites with high density polyethylene (HDPE. The mechanical properties of the composites prepared from chemically modified cellulose fibres were found to increase compared to those of bleached fibres. Tensile strengths of the composites showed a decreasing trend with increasing filler content. However, the values for the chemically modified cellulose fibres/HDPE composites at all mixing ratios were found to be higher than that of neat HDPE. Results of water immersion tests showed that the water absorption affected the mechanical properties. The fracture surfaces of the composites were recorded using scanning electron microscopy (SEM. The SEM micrographs revealed that interfacial bonding between the modified filler and the matrix was significantly improved by the fibre modification.

NANOFIBRILLATED CELLULOSE (NFC AS A POTENTIAL REINFORCEMENT FOR HIGH PERFORMANCE CEMENT MORTAR COMPOSITES

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Mònica Ardanuy,

2012-07-01

Full Text Available In this work, nanofibrillated cellulose (NFC has been evaluated as a potential reinforcement for cement mortar composites. Two types of vegetable fibres with different composition and properties (cellulose content and microfibrillar angle, sisal, and cotton linters pulps, were initially characterised in order to assess their reinforcing capability. Sisal pulp was found to be most suitable as reinforcement for the brittle cementitious matrix. Nanofibrillated cellulose was produced by the application of a high intensity refining process of the sisal pulp. It was found that 6 hours of refining time was required to obtain the desired nanofibrillation of the fibers. Cement mortar composites reinforced with both the sisal fibres and the nanofibrillated cellulose were prepared, and the mechanical properties were determined under flexural tests. The cement mortar composites reinforced with the nanofibrillated cellulose exhibited enhanced flexural properties, but lower values of fracture energy, than the ones reinforced with the conventional sisal fibres.

Optical and Physical Properties of ONP Deinked Pulp

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Iman Akbarpoor

2012-01-01

Full Text Available Enzymes are protein molecules with complex structures that accelerate the biochemical reactions. Activity of these chemical compounds is accomplished at limited range of pH, temperature and concentration. In this study, the effects of different concentrations of cellulose enzyme were investigated on deinking of old newsprint. Old newsprint (ONP was repulped at 5% consistency for 10 minutes in disintegrator with total revolution number of 26500. Enzymatic treatments of recycled ONP pulp were done under constant conditions (10% consistency,treatment time of 15 minutes, pH range of 5-5.5 at different cellulose concentrations of 0.025, 0.05, 0.1 and 0.2% (based on oven-dry waste paper. The optical and physical properties of the standard paper (60g/m2 made at different concentrations of cellulose were evaluated in comparison with control pulp (untreated ONP pulp with cellulase. Overall, the results achieved by comparison the optical properties of the paper produced indicated that using cellulase in deinking of ONP led to increase the brightness and the yellowness and decrease the opacity. The brightness was improved to a maximum level of 47.5 ISO %, but the yellowness was decreased to a minimum level of 11.3 ISO %, while the brightness reduced and the yellowness increased at higher concentrations than 0.05% cellulase. The highest opacity of 99.3 ISO % was achieved using 0.1% cellulase even higher than control pulp. The results gained by comparison the physical properties of the paper showed that using cellulase resulted in decrease of paper calliper, air resistance and density and improve the freeness of pulp

Formation of Irreversible H-bonds in Cellulose Materials

Science.gov (United States)

Umesh P. Agarwal; Sally A. Ralph; Rick S. Reiner; Nicole M. Stark

2015-01-01

Understanding of formation of irreversible Hbonds in cellulose is important in a number of fields. For example, fields as diverse as pulp and paper and enzymatic saccharification of cellulose are affected. In the present investigation, the phenomenon of formation of irreversible H-bonds is studied in a variety of celluloses and under two different drying conditions....

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

Isolation and characterization of α-cellulose from blank bunches of palm oil and dry jackfruit leaves with alkaline process NaOH continued with bleaching process H2O2

Science.gov (United States)

Tristantini, Dewi; Dewanti, Dian Purwitasari; Sandra, Cindy

2017-11-01

Alpha cellulose is a pure form of cellulose. Cellulose is a natural polymer in the form of carbohydrates (polysaccharides) that has fiber which is white, insoluble in water, renewable, easily decomposes, and non-toxic. Cellulosic sources are abundant in nature even in untapped biomass wastes. In this study, cellulose was isolated from Empty Palm Oil Bunches (EPOB) of 45% and Dry Jackfruit Leaves (DJL) of 21.45%. This study aims to obtain optimum yield of cellulose at NaOH concentration and cellulose characterization with water content, FTIR, and SEM analysis. The optimum α-cellulose yield was determined by alkali process with 8, 10, 12 and 14% (w/v) NaOH variations at 90-100 °C for 3 hours to remove hemicellulose and lignin followed by bleaching process with H2O2 10% (w/v) at 80-90 °C for 1.5 h to obtain pure α-cellulose. The optimum yield of EPOB cellulose was 38,562% in 12% NaOH and DJL was 7.27% in 10% NaOH. The water content in OPB cellulose was 4.38% and DJL was 6.37%. A typical cellulose-forming functional group seen in FTIR (Fourier Transform Infra-Red) and morphological results appears in SEM (Scanning Electron Microscopy) analysis. From FTIR analysis result shows cellulose from EPOB and DJL contains O-H, C-H, and C-O. SEM analysis shows fibers from EPOB and DJL are uniform and have pores. However, DJL fibers have white patches, which suspected to be impurities.

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)

Investigation of pulping and paper making potential of weeds

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omid Ghaffarzadeh Mollabashi

2017-08-01

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

Isolation and surface modification of cellulose nanocrystals from sugarcane bagasse waste: From a micro- to a nano-scale view

Science.gov (United States)

Ferreira, F. V.; Mariano, M.; Rabelo, S. C.; Gouveia, R. F.; Lona, L. M. F.

2018-04-01

This work presents the isolation and functionalization of cellulose nanocrystals (CNCs) extracted from sugarcane bagasse (SCB). CNCs were obtained by acid hydrolysis of bleached bagasse pulp and functionalized with adipic acid. The results showed that unmodified CNCs exhibit both a high crystallinity index and a significant aspect ratio. Surface modification with adipic acid decreases the nanocrystal dimensions due to removal of the amorphous region between the crystalline domains and also changes the electrostatic repulsion and hydrophilic affinity of CNCs. Unmodified CNCs offer potential applications as reinforcing phase in hydrophilic polymeric matrices, while modified CNCs interact better with hydrophobic matrices. The use of CNCs as reinforcement in polymer nanocomposites expands the application of this renewable material and increases its added value, providing nonenergy-based markets for the main biomass of the sugarcane industry.

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

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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.

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.

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

NARCIS (Netherlands)

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

1997-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1980-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2007-07-01

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

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

Science.gov (United States)

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

2010-02-01

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

A Method for Producing Microcrystalline Cellulose from Hemp Fibers

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Valerii A. Barbash

2018-03-01

Conclusions. The proposed technology for the MCC production from hemp fibers reduces the cost of finished products by eliminating the bleaching stage of pulp as well as due to the use of domestic renewable plant raw materials, in particular hemp fibers compared with imported cotton or softwood pulp. The obtained MCC meets the requirements of technical conditions and can be used in the chemical industry as a sorbent or filler in the production of plastics and a water stabilizer for paints and emulsions.

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

Science.gov (United States)

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

2009-01-01

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

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

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maryam allahdadi

2016-12-01

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

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.

Enzymatically-Mediated Co-Production of Cellulose Nanocrystals and Fermentable Sugars

Directory of Open Access Journals (Sweden)

Dawit Beyene

2017-10-01

Full Text Available Cellulose nanocrystals (CNCs can be extracted from cellulosic materials through the degradation of non-crystalline cellulose domains in the feedstock via acid hydrolysis. However, the sugars released from the hydrolysis process cannot be easily recovered from the acid waste stream. In this study, cellulases were used to preferentially degrade non-crystalline domains with the objectives of recovering sugars and generating a feedstock with concentrated CNC precursors for a more efficient acid hydrolysis process. Filter paper and wood pulp substrates were enzyme-treated for 2–10 h to recover 20–40 wt % glucose. Substantial xylose yield (6–12 wt % was generated from wood pulp. CNC yields from acid hydrolysis of cellulases-treated filter paper, and wood pulp improved by 8–18% and 58–86%, respectively, when compared with the original substrate. It was thought that CNC precursors accumulated in the cellulases-treated feedstock due to enzymatic digestion of the more accessible non-crystalline celluloses. Therefore, acid hydrolysis from enzyme-treated feedstock will require proportionally less water and reagents resulting in increased efficiency and productivity in downstream processes. This study demonstrates that an enzymatically-mediated process allows recovery of fermentable sugars and improves acid hydrolysis efficiency for CNC production.

Production of Nanocellulose from Rice Husk

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Shaghayegh Rezanezhad

2013-11-01

Full Text Available In this work, nanocellulose was produced from rice husk, as a lignocellulosic waste of rice. Initially, purified cellulose was produced with chemo-mechanical and soda-anthraquinone (soda/AQ pulping and bleaching. The purified cellulose was then sonicated for 15 min using an ultrasonic processor, resulted in nanocellulose. The nanocellulose obtained by sonification has been characterized by atomic force microscopy (AFM, X-ray diffraction (XRD and thermogravimetric analysis (TGA. Diameter of nanocellulose from rice husk by chemical method was 30-40 nm and that of produced by soda-AQ pulping method were 10-20 nm. The nanocellulose crystallinity for chemical method obtained 60% and for that of produced with soda-AQ pulping method was 66%. The degradation onset temperature for nanocellulose from rice husk by chemical method was 165°C and that of produced with soda-AQ pulping method were 188°c. The thermal behaviors of nanocellulose and purified cellulose were almost the same, suggesting the ultrasonic treatment had minor effect on the thermal decomposition of the nanocellulose.

Development of Cellulose Nano fibre (CNF) Derived From Kenaf Bast Fibre and Its Potential in Enzyme Immobilization Support

International Nuclear Information System (INIS)

Safwan Sulaiman; Mohd Noriznan Mokhtar; Mohd Nazli Naim; Azhari Samsu Baharuddin

2016-01-01

This research mainly focuses on developing a natural cellulose nano fibre (CNF) from kenaf bast fibre and its potential for enzyme immobilization support. CNF was isolated by using a combination between chemical and mechanical treatments such as alkaline process and high-intensity ultrasonication process to increase the efficiency of hemicelluloses and lignin removal, and to reduce its size into nano-order. The morphological study was carried out by using scanning electron microscope (SEM), indicating most of CNF diameter in range of 50-90 nm was obtained. The result of chemical analysis shows that cellulose content of raw bast fibre, bleached pulp fibre and CNF are 66.4 %, 83.7 % and 90.0 %, respectively. By decreasing the size of cellulose fibre, it increases the number of (O-H) group on the surface that plays as important role in enzyme immobilization. Covalent immobilization of cyclodextrin glucanotransferase (CGTase) onto CNF support resulted in about 95.0 % of protein loading with 69.48 % of enzyme activity, indicating high immobilization yield of enzyme. The enzymatic reaction of immobilized CGTase was able to produce more than 40 % yield of α-CD. Reusability profile of immobilized CGTase resulted in more than 60 % of retained activity up to 7 cycles. Therefore, the CNF is highly potential to be applied as enzyme immobilization support. (author)

The use of near-infrared scanning for the prediction of pulp yield and ...

African Journals Online (AJOL)

Calibration models to predict pulp yield, cellulose and lignin content were developed by applying chemometrics and partial least squares regression. Validation and determination of prediction accuracy of the models were performed using independent data. The prediction of cellulose and lignin were acceptable with ...

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

Science.gov (United States)

Khoroushi, Maryam; Feiz, Atieh; Khodamoradi, Roghayeh

2010-01-01

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

Influence of bleach activators on the fabric made from cotton (gossypium hamster l.)

International Nuclear Information System (INIS)

Asif, H.M.; Iftikhar, M.; Shahbaz, B.

2013-01-01

Raw cotton contains various type of trash and most of the impurities are removed during the spinning process but still the cotton fabric coming from the weaving or knitting process always contains some impurities. Some time cotton fabric gets the oil, stains and coloured materials which affect the quality of dyed fabric. Bleaching is a process that eliminates unwanted coloured matters from the fibres, yarn and fabrics. A bleaching agent is a material that lightens or whitens a substrate through chemical action. Hydrogen peroxide is by far the most commonly used oxidative bleaching agent for cotton and its blends, accounting for more than 90 percent of all the bleaching agents. The use of activators to enhance the bleaching performance of hydrogen peroxide for cellulosic materials has gained popularity now a day. In this context the main objectives of this paper are to study the influence of different bleaching activators on cotton fabric and to give implications for textile extension.The results indicate that the activators with different concentrations, along with different concentrations of hydrogen peroxide (H/sub 2/O/sub 2) have significant influence on the bleaching performance of cotton fabric. (author)

Research on Wheat Straw Pulping with Ionic Liquid 1-Ethyl-3-Methylimidazole Bromide

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Wei Song

2016-12-01

Full Text Available In this paper, the pulping process of wheat straw using ionic liquid 1-ethyl-3-methylimidazolium bromide ([Emim]Br as the digestion liquor is presented. The influence of pulping conditions on the pulp yield are analysed by single-factor and orthogonal experiments, and optimum pulping conditions are obtained. The average pulp yield reaches 44 %, and the average recovery rate of ionic liquid is 93.5 %. The XRD pattern shows no obvious change in the crystal structure of the wheat straw cellulose. Additionally, the SEM image illustrates that there are many fine fibres in the pulp and the spaces between the fibres are large.

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

Science.gov (United States)

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

2011-01-01

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

Studies on the utilization of agricultural residues in the manufacture of pulp and paper, and industrial chemicals

Energy Technology Data Exchange (ETDEWEB)

Joshi, V.S.; Kamath, G.P.; Basu, S.

1980-03-15

While demand for pulp and paper products in India is increasing at the annual rate of 7 to 8%, availability of cellulosic raw material to meet the ever increasing demand is becoming a serious problem. It has been estimated that bamboo, the traditional source of cellulosic raw material in India, even after ensuring the most scientific and best possible exploitation, could provide less than 50% of the requirement. In a big agricultural country like India, agri-residues like straws and bagasse, along with jute sticks, available in huge quantity, could provide substantial amount of cellulosic resources to the pulp and paper industry. Realizing the importance of agri-residue utilization in Indian economy, a series of research projects have been initiated and completed during the last 15 years to study the techno-economic feasibility of manufacturing pulp, paper, and industrial chemicals, based on rice and wheat straws, bagasse, and jute sticks. The economic advantages of the mechano-chemical pulping process, as compared to the conventional pressure, pulping process, for the conversion of agri-residues into pulp and paer is evaluated. For highlighting the importance of agri-residues in the field of useful chemical recovery possibilities, experimental data are given on the saccarification of agri-residues into reducing sugars by the simple acid hydrolysis method with the help of concentrated sulfuric acid.

Preparation and Properties of Nanocellulose from Organosolv Straw Pulp

Science.gov (United States)

Barbash, V. A.; Yaschenko, O. V.; Shniruk, O. M.

2017-03-01

The object of this work is to present a study of nanocellulose preparation from organosolv straw pulp (OSP) and its properties. OSP was obtained through thermal treatment in the system of isobutyl alcohol-H2O-KOH-hydrazine followed by processing in the mixture of acetic acid and hydrogen peroxide for bleaching and removal of residual non-cellulosic components. We have obtained nanocellulose from OSP through acid hydrolysis with lower consumption of sulfuric acid and followed by ultrasound treatment. The structural change and crystallinity degree of OSP and nanocellulose were studied by means of SEM and XRD techniques. It has been established that nanocellulose has a density up to 1.3 g/cm3, transparency up to 70%, crystallinity degree 72.5%. The TEM and AFM methods shown that nanocellulose have diameter of particles in the range from 10 to 40 nm. Thermogravimetric analysis confirmed that nanocellulose films have more dense structure and smaller mass loss in the temperature range 220-260 °C compared with OSP. The obtained nanocellulose films had high Young's modulus up to 11.45 GPa and tensile strength up to 42.3 MPa. The properties of obtained nanocellulose from OSP exhibit great potential in its application for the preparation of new nanocomposite materials.

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

Science.gov (United States)

Andreu, Glòria; Vidal, Teresa

2013-03-01

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

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. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

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

2015-01-01

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

Acid bi-sulphite pulping effects on hardwoods and a softwood revealed by atomic force microscopy

CSIR Research Space (South Africa)

Chunilall, Viren

2009-12-01

Full Text Available Wood fibres are the raw material used in the production of dissolving pulp for the manufacture of cellulose derivatives such as viscose and cellulose acetate. At the microscopic level, the wood cell wall is organised in layers with different...

PENGGUNAAN ASAM PERASETAT PADA PROSES DELIGNIFIKASI PULP ACETOSOLV DARI AMPAS TEBU DAN BAMBU BETUNG

Directory of Open Access Journals (Sweden)

Ahmad Sapta Zuidar

2014-07-01

Full Text Available Acetosolv process produced dark pulp because of the high lignin content.  Therefore ,  delignification  process is needed. This process uses peracetic acid to improve pulp qualities. The objective of this research was to determine the effect of different concentrations of peracetic acid against the characteristics of pulp acetosolv from bagasse and bamboo betung.  The research was arranged in a Complete Randomized Block Design with a single treatment and 4 replications.  The treatment used peracetic acid with six levels concentration (9%, 11%, 13%, 15%, 17%, 19% at a temperature of 85oC for 3 hours. The homogenity and additivity of the data were  analyzed using Bartlett and Tuckey Tests, then they were analyze for ANOVA to see if there is any difference among means, and then processed further using  Least Significant Difference at level of 1% and 5%.  The results showed that the concentration of peracetic acid had significant effect on yield, cellulose, hemicellulose, lignin, and organoleptic color pulp from bagasse and bamboo betung.  The best results showed that the concentration of peracetic acid 15% with cooking duration of  3 hours gave the best pulp. The pulp contained 85.837% of cellulose , 7.757% of hemicellulose , 1.758% of lignin , 73.048% of yield  and  the average organoleptic score for the pulp color was 4.3. Keywords:   acetosolv pulp,  baggase, bamboo,  delignification, paracetic acid

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

OpenAIRE

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

2015-01-01

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

Structural and morphological characterization of cellulose pulp

CSIR Research Space (South Africa)

Ocwelwang, A

2015-09-01

Full Text Available Understanding the structure of cellulose is of utmost importance in order to enhance its accessibility and reactivity to chemical processing. Therefore, the aim of this study was to evaluate the effect of ultrasound pretreatment on the structure...

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

Science.gov (United States)

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

2013-08-01

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

Current characterization methods for cellulose nanomaterials.

Science.gov (United States)

Foster, E Johan; Moon, Robert J; Agarwal, Umesh P; Bortner, Michael J; Bras, Julien; Camarero-Espinosa, Sandra; Chan, Kathleen J; Clift, Martin J D; Cranston, Emily D; Eichhorn, Stephen J; Fox, Douglas M; Hamad, Wadood Y; Heux, Laurent; Jean, Bruno; Korey, Matthew; Nieh, World; Ong, Kimberly J; Reid, Michael S; Renneckar, Scott; Roberts, Rose; Shatkin, Jo Anne; Simonsen, John; Stinson-Bagby, Kelly; Wanasekara, Nandula; Youngblood, Jeff

2018-04-23

A new family of materials comprised of cellulose, cellulose nanomaterials (CNMs), having properties and functionalities distinct from molecular cellulose and wood pulp, is being developed for applications that were once thought impossible for cellulosic materials. Commercialization, paralleled by research in this field, is fueled by the unique combination of characteristics, such as high on-axis stiffness, sustainability, scalability, and mechanical reinforcement of a wide variety of materials, leading to their utility across a broad spectrum of high-performance material applications. However, with this exponential growth in interest/activity, the development of measurement protocols necessary for consistent, reliable and accurate materials characterization has been outpaced. These protocols, developed in the broader research community, are critical for the advancement in understanding, process optimization, and utilization of CNMs in materials development. This review establishes detailed best practices, methods and techniques for characterizing CNM particle morphology, surface chemistry, surface charge, purity, crystallinity, rheological properties, mechanical properties, and toxicity for two distinct forms of CNMs: cellulose nanocrystals and cellulose nanofibrils.

Effect of cellulose-based fibers extracted from pineapple (Ananas ...

African Journals Online (AJOL)

New polyurethane foams were fabricated utilizing cellulose-based fibers extracted from pineapple (Ananas comosus) leaf as raw material. The pineapple leaf fibers (PALF) were treated with alkali and subsequently bleached to enhance its fiber-matrix adhesion. Polyurethane composites have been prepared by ...

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

OpenAIRE

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

2008-01-01

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

Extraction of cellulose nanofibers from Pinus oocarpa residues

Energy Technology Data Exchange (ETDEWEB)

Manrich, Anny; Martins, Maria Alice, E-mail: anny@daad-alumni.de [EMBRAPA Instrumentacao, Sao Carlos, SP (Brazil); Moraes, Jheyce Cristina; Pasquoloto, Camila [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil)

2016-07-01

Full text: Pinus oocarpa, which wood is moderately hard and tough, is planted in Brazil for reforestation and employed for timber production used in constructions. The wood residues, such as shavings, bark and sawdust represent 30% to 50% of the total volume of wood production, of which the sawdust is 10%{sup 1}. Cellulose nanofibers is nanomaterials having a diameter between 5 nm and 20 nm and a length of up to hundreds of nm. To obtain nanofibers from cellulose sources, such as sisal and sugarcane bagasse, is used chemical processes, in which the lignocellulosic material initially undergoes pre-treatments to promote partial separation of the cellulose, such as mercerisation and bleaching thus disposing lignin and hemicellulose components. Sequentially, by controlled acid hydrolysis, amorphous regions of the cellulose are removed, and crystalline cellulose is isolated in the form of cellulose nanofibers. In this work, nanofibers from sawdust of Pinnus oocarpa, containing 44.8 wt% of cellulose 20.6 wt% hemicellulose and 30.0 wt% insoluble lignin were isolated by mercerisation (NaOH 5%, 80°C, 120 min), followed by bleaching (NaOH + acetic acid + NaClO{sub 2}, 80 deg C, 240min) and acid hydrolysis (60 wt% sulfuric acid, 45 °C, 40min). Nanofibers obtained were characterized by DRX and SEM-FEG. Results showed that, for used conditions, fiber acid hydrolysis was not complete, therefore a biphasic suspension was formed. Crystallinity index achieved was not much higher than that from pinus fiber itself, increasing from 62% to 65% and signs of cellulose type II were observed. SEM images showed elongated fibers, which have diameter of 15 ± 5 nm and length of hundreds of nm, what means that they have a large L/D aspect ratio. Nanofiber extraction yield was very low (1.3 wt% of initial residue). All steps of the process are being reviewed aiming at better results. 1) Morais, S. A. L.; Nascimento E. A. e D. C. Melo, 2005, R. Árvore, 29, 3, 461-470. (author)

Isolation and characterization of pulp from sugarcane bagasse and rice straw

International Nuclear Information System (INIS)

Saiful Azhari, S.; Suhardy, D.; Kasim, F.H; Nazry Saleh, M.

2007-01-01

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

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....... Tensile testing revealed that MFC 2-reinforced films exhibited a more ductile behavior and that MFC 1-reinforced films had higher modulus of elasticity (E-modulus) at MFC loadings of 50 wt % or higher. Pure MFC films had relatively low oxygen permeability values when data were compared with those...

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)

Engineering structural integrity issues in the pulp and paper industry

International Nuclear Information System (INIS)

Garner, A.; Singbeil, D.

2002-01-01

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

Preparation of micro-fibrillated cellulose based on sugar palm ijuk (Arenga pinnata) fibres through partial acid hydrolysis

Science.gov (United States)

Saputro, A.; Verawati, I.; Ramahdita, G.; Chalid, M.

2017-07-01

The aim of this study was to isolate and characterized micro-fibrillated cellulose (MFC) from sugar palm/ijuk fibre (Arenga pinnata) by partial sulfuric acid hydrolysis. Cellulose fibre was prepared by repeated treatments with 5 wt% sodium hydroxide 2 h at 80°C, followed by bleaching with 1.7 wt% sodium chlorite for 2 h at 80°C in acidic environment under stirring. MFC was prepared by partial hydrolysis with sulfuric acid in various concentrations (30, 40, 50, and 60 % for 45 min at 45 °C) under stirring. Fourier Transform Infrared, Field Emission Scanning Electron Microscope, Thermo Gravimetric Analyzer and X-ray Diffraction characterized cellulose fibre and MFC. FTIR measurements showed that alkaline and bleaching treatments were effective to remove non-cellulosic constituents such as wax, lignin and hemicellulose. FESEM observation revealed conversion into more clear surface and defibrillation of cellulosic fibre after pre-treatments. XRD measurement revealed increase in crystallinity after pre-treatments and acid hydrolysis from 54.4 to 87.8%. Thermal analysis showed that increasing acid concentration reduced thermal stability.

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.

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.

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.

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

Science.gov (United States)

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

2017-11-01

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

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

International Nuclear Information System (INIS)

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

1979-01-01

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

Environmentally friendly cellulose-based polyelectrolytes in wastewater treatment.

Science.gov (United States)

Grenda, Kinga; Arnold, Julien; Gamelas, José A F; Rasteiro, Maria G

2017-09-01

Natural-based polyelectrolytes (PELs), with all the advantages coming from being produced from renewable and biodegradable sources, are a potential solution for the removal of dyes from wastewater. In this work, surplus Eucalyptus bleached cellulose fibres from a paper mill were modified to increase the charge and solubility of cellulose. First, reactive aldehyde groups were introduced in the cellulose backbone by periodate oxidation of cellulose. Further modification with alkylammonium produced positively charged cellulose-based PELs. The final products were characterized by several analytical techniques. The PEL with the highest substitution degree of cationic groups was evaluated for its performance in decolouration processes, bentonite being used as aid. This was found to be effective for colour removal of either anionic or cationic dyes. Bio-PELs can thus be considered as very favourable eco-friendly flocculation agents for decolouration of harsh effluents from several industries, considering their biodegradable nature and thus the ability to produce less sludge.

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.

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

2017-09-01

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 H 2 SO 4 and dissolution of cotton was achieved with a mixture of NaOH-thiourea-urea-H 2 O 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. Copyright © 2017 Elsevier B.V. All rights reserved.

The Lignin-Degrading Enzyme, Laccase from Marine Fungi : Biochemical and Molecular Approaches

Digital Repository Service at National Institute of Oceanography (India)

DeSouza-Ticlo, D.

system that provides a good environment for the fungus to thrive in. Fungi decay the woody substrate to alter the lignin in the cell walls of the wood, which therefore ‘softens’ the wood chips. This process is non-polluting since it is chemical-free... % it also saves about $ 9 - $ 20 per ton of pulp (http://www.biopulping.com/2.html). The paper-pulp is then subjected to alkali-treatment to free the cellulose fibers from the hemicellulose and lignin. This is then bleached to reduce the colour due...

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.

Spatially Resolved Characterization of Cellulose Nanocrystal-Polypropylene Composite by Confocal Raman Microscopy

Science.gov (United States)

Umesh P. Agarwal; Ronald Sabo; Richard S. Reiner; Craig M. Clemons; Alan W. Rudie

2012-01-01

Raman spectroscopy was used to analyze cellulose nanocrystal (CNC)–polypropylene (PP) composites and to investigate the spatial distribution of CNCs in extruded composite filaments. Three composites were made from two forms of nanocellulose (CNCs from wood pulp and the nanoscale fraction of microcrystalline cellulose) and two of the three composites investigated used...

A novel approach for the reuse of the textile bleaching wastewater

International Nuclear Information System (INIS)

Shaikh, I.A.

2015-01-01

In this paper, the efficiency of used hydrogen peroxide (H/sub 2/O/sub 2/) bleach bath was assessed for the elimination of hydrolyzed unfixed reactive dyes from cellulosic fabrics. The aim of this study was to reuse textile wastewater and develop a new textile dyeing and wash-off method with small quantities of water and chemicals, without compromising quality of dyeing. For this purpose, spent bleach bath having H/sub 2/O/sub 2/ was collected from a textile industry and used in wash-off step of fabric after dyeing with reactive dyes to determine colour fastness properties and shade strength of selected reactive dyes. Five dyeings were carried out, using C. I. Reactive Yellow 138, C. I. Reactive Orange 122, C. I. Reactive Red 195, C. I. Reactive Blue 221, and C. I. Reactive Black 5 and dyed samples were passed through both conventional wash-off and new wash-off method containing spent bleach bath. Washing fastness, rubbing fastness, change of colour, and magnitude of total colour difference ( E*) values of both washed-off fabrics were compared. The colourfastness properties and final shade of fabrics washed-off with spent bleach were found to be comparable to those washed-off conventionally. This study concludes that spent bleach bath containing H/sub 2/O/sub 2/ is a potential nominee for the removal of hydrolyzed reactive dyes from cotton fabrics. (author)

Resistant-hemicelluloses toward successive chemical treatment during cellulose fibre extraction

Science.gov (United States)

Naqiya, F. M. Z.; Ahmad, I.; Airianah, O. B.

2018-04-01

Lignocellulosic materials have high demand bio-polymers industries as it is rich in cellulose but other residues that still remain in the extracted cellulose might influence the ability of cellulose-rich material to interact with other polymers. In this study, cellulose fibre was extracted from oil palm frond (OPF) using alkali and bleaching treatment. The morphological changes of each sample after every treatment was observed using Scanning Electron Microscope (SEM) and was further chemically extracted and quantitatively evaluated via spectrophotometric method. The non-cellulosic component was found predominantly contained hemicelluloses and these remaining hemicelluloses were hydrolysed and the monosaccharides of hemicelluloses were visualised by Thin Layer Chromatography (TLC). Xylose, arabinose, mannose and glucose were detected and therefore, it is suggested that the plausible type of resistant-hemicelluloses in OPF extracted fibre are arabinoxylan, glucomannan and/or glucan.

Zinc oxide nanorod clusters deposited seaweed cellulose sheet for antimicrobial activity.

Science.gov (United States)

Bhutiya, Priyank L; Mahajan, Mayur S; Abdul Rasheed, M; Pandey, Manoj; Zaheer Hasan, S; Misra, Nirendra

2018-06-01

Seaweed cellulose was isolated from green seaweed Ulva fasciata using a common bleaching agent. Sheet containing porous mesh was prepared from the extracted seaweed crystalline cellulose along with zinc oxide (ZnO) nanorod clusters grown over the sheet by single step hydrothermal method. Seaweed cellulose and zinc oxide nanorod clusters deposited seaweed cellulose sheet was characterized by FT-IR, XRD, TGA, and SEM-EDX. Morphology showed that the diameter of zinc oxide nanorods were around 70nm. Zinc oxide nanorod clusters deposited on seaweed cellulose sheet gave remarkable antibacterial activity towards gram-positive (Staphylococcus aureus, Bacillus ceresus, Streptococcus thermophilis) and gram-negative (Escherichia coli, Pseudomonas aeruginous) microbes. Such deposited sheet has potential applications in pharmaceutical, biomedical, food packaging, water treatment and biotechnological industries. Copyright © 2018 Elsevier B.V. All rights reserved.

Sugar, acid and furfural quantification in a sulphite pulp mill: Feedstock, product and hydrolysate analysis by HPLC/RID.

Science.gov (United States)

Llano, Tamara; Quijorna, Natalia; Andrés, Ana; Coz, Alberto

2017-09-01

Waste from pulp and paper mills consist of sugar-rich fractions comprising hemicellulose derivatives and cellulose by-products. A complete characterisation of the waste streams is necessary to study the possibilities of an existing mill. In this work, four chromatographic methods have been developed to obtain the most suitable chromatographic method conditions for measuring woody feedstocks, lignocellulosic hydrolysates and cellulose pulp in sulphite pulping processes. The analysis of major and minor monosaccharides, aliphatic carboxylic acids and furfurals has been optimised. An important drawback of the spent liquors generated after sulphite pulping is their acidic nature, high viscosity and adhesive properties that interfere in the column lifetime. This work recommends both a CHO-782Pb column for the sugar analysis and an SH-1011 resin-based cross-linked gel column to separate low-molecular-weight chain acids, alcohols and furfurals. Such columns resulted in a good separation with long lifetime, wide pH operating range and low fouling issues.

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

Science.gov (United States)

Apiwatanapiwat, Waraporn; Murata, Yoshinori; Kosugi, Akihiko; Yamada, Ryosuke; Kondo, Akihiko; Arai, Takamitsu; Rugthaworn, Prapassorn; Mori, Yutaka

2011-04-01

In order to develop a method for producing fuel ethanol from cassava pulp using cell surface engineering (arming) technology, an arming yeast co-displaying α-amylase (α-AM), glucoamylase, endoglucanase, cellobiohydrase, and β-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 β-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.

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.)

Structure and properties of new natural cellulose fabrics from Cordia dichotoma

CSIR Research Space (South Africa)

Jayaramudu, J

2011-10-01

Full Text Available Natural cellulose fabrics were newly identified from the branches of the Cordia dichotoma. The structure of the fabrics was analysed by FTIR and X-ray diffraction. The net-like morphologies of the untreated, bleached and 5% NaOH (alkali) treated...

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.

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

International Nuclear Information System (INIS)

Jan, Niemi

2010-01-01

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

Structural insights into the β-xylosidase from Trichoderma reesei

International Nuclear Information System (INIS)

Rojas, Adriana L.; Fischer, Hannes; Polikarpov, Igor; Craievich, Aldo Felix

2005-01-01

Xylan is a major structural polysaccharide in plant cells, and is the second most abundant polysaccharide in nature, accounting for approximately one-third of all renewable organic carbon on earth. Xylan together with cellulose (1,4-β-glucan) and lignin (a complex polyphenolic compound) make up the major polymeric constituents of plant cell walls, recently, there was a significant industrial interest in Xylan and its hydrolytic enzymatic complex, as a supplement in animal feed, for the manufacture of bread, food and drinks, textiles, bleaching of cellulose pulp, ethanol and xylitol production. (author)

Structural insights into the {beta}-xylosidase from Trichoderma reesei

Energy Technology Data Exchange (ETDEWEB)

Rojas, Adriana L.; Fischer, Hannes; Polikarpov, Igor [Sao Paulo Univ. (USP), Sao Carlos, SP (Brazil). Inst. de Fisica; Eneiskaya, Elena V.; Kulminskaya, Anna A.; Shabalin, Konstantin A.; Neustroev, Kirill N.; Golubev, Alexander M. [Petersburg Nuclear Physics Inst., Moskow (Russian Federation); Craievich, Aldo Felix [Sao Paulo Univ. (USP), SP (Brazil). Inst. de Fisica

2005-07-01

Xylan is a major structural polysaccharide in plant cells, and is the second most abundant polysaccharide in nature, accounting for approximately one-third of all renewable organic carbon on earth. Xylan together with cellulose (1,4-{beta}-glucan) and lignin (a complex polyphenolic compound) make up the major polymeric constituents of plant cell walls, recently, there was a significant industrial interest in Xylan and its hydrolytic enzymatic complex, as a supplement in animal feed, for the manufacture of bread, food and drinks, textiles, bleaching of cellulose pulp, ethanol and xylitol production. (author)

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

OpenAIRE

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

2012-01-01

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

Preparation nanowhiskers pulp from residue of palm fiber Attalea funifera Martius

International Nuclear Information System (INIS)

Silva, J.B.A. da; Miranda, C.S.; Jose, N.M.; Vargas, F.P.; Druzian, J.I.

2010-01-01

The residue from piassava fiber is higher in cellulose and lignin. This study aimed to extract the pulp and the development of methodology for preparation nanowhiskers from residue fiber. The first step extraction of cellulose, the second step to obtain the nanoparticles by acid hydrolysis (H 2 SO 4 ). The samples were characterized by: SEM, chemical composition, TGA, FTIR and XRD. The XRD result shows that cellulose is of type I and TGA shows two events at 54 deg C and 370 deg C attributed to mass loss of water and cellulose, respectively. After hydrolysis, X-ray diffraction showed an intense reflection 2θ= 22.3 deg and an increase in the degree of crystallinity to 70% which is an indication of the formation of nanowhiskers. (author)

Extraction and Characterization of Nano cellulose from Coconut Fiber

International Nuclear Information System (INIS)

Nor Liyana Ahmad; Ishak Ahmad

2013-01-01

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

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

Science.gov (United States)

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

2015-01-01

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

THE FUNGAL ABILITY FOR BIOBLEACHING/BIOPULPING/BIOREMEDIATION OF LIGNIN-LIKE COMPOUNDS OF AGRO-INDUSTRIAL RAW MATERIAL

Directory of Open Access Journals (Sweden)

Ana Maria Queijeiro López

Full Text Available Lignin is present in plant cell secondary wall, associated to carbohydrates preventing their efficient hydrolysis, and cellulose pulp manufacture basically consists in breaking down the middle lamella of plant cells, individualizing fibers such as cellulose from the other biopolymers. Different levels of lignocellulose are found in plant residues and they can be decomposed by extracellular fungal lignin modifying enzymes, used as a tool to reduce waste materials in contaminated soils and effluents. In the paper mill industries, for instance, they are a suitable or complementary alternative to the traditional methods of pulping/bleaching, contributing to improve paper strength as well as to reduce the pitch content, the quantity of chemicals and the consume of electrical energy. The aim of this review was to describe the fungal degradation of lignocellulosic like-material, the non-specific enzymatic aspects of the attack of wood and agricultural wastes, the fungal ability for biosorption and bioconversion, and its applications in the pulp/paper industry and bioremediation.

Effect of cellulose nanocrystals (CNC) addition and citric acid as co-plasticizer on physical properties of sago starch biocomposite

Science.gov (United States)

Nasution, Halimatuddahliana; Afandy, Yayang; Al-fath, M. Thoriq

2018-04-01

Cellulose has potential applications in new high-performance materials with low environmental impact. Rattan biomass is a fiber waste from processing industry of rattan which contains 37,6% cellulose. The high cellulose contents of rattan biomass make it a source of cellulose nanocrystals as a filler in biocomposite. Isolation of alpha cellulose from biomass rattan was prepared by using three stages: delignification, alkalization, and bleaching. It was delignificated with 3,5% HNO3 and NaNO2, precipitated with 17,5% NaOH, bleaching process with 10% H2O2. Nanocrystals obtained through the hydrolysis of alpha cellulose using 45% H2SO4 and followed by mechanical processes of ultrasonication, centrifugation, and filtration with a dialysis membrane. Sago starch biocomposites were prepared using a solution casting method, which includes 1-4 wt % cellulose nanocrystals rattan biomass as fillers, 10-40 wt% citric acid as co-plasticizer and 30 wt% glycerol as plasticizer. The results of TEM and FTIR characteristic of cellulose nanocrystals show spherical like shape FTIR and chemical composition analysis demonstrated that lignin and hemicellulose structures were successfully removed. Biocomposite characteristic consists of density and water absorption. The results showed the highest density values were 0,266 gram/cm3 obtained at an additional of 3% cellulose nanocrystals rattan biomass and 30% citric acid. The lowest water absorption was 7,893% obtained at an additional of 4% cellulose nanocrystals rattan biomass and 10% citric acid.

Humic acid adsorption onto cationic cellulose nanofibers for bioinspired removal of copper( ii ) and a positively charged dye

KAUST Repository

Sehaqui, H.; Perez de Larraya, Uxua; Tingaut, P.; Zimmermann, T.

2015-01-01

© The Royal Society of Chemistry. Waste pulp residues are herein exploited for the synthesis of a sorbent for humic acid (HA), which is a major water pollutant. Cellulose pulp was etherified with a quaternary ammonium salt in water thereby

Avoiding total reduced sulfur (TRS) emissions from sodium sulfite pulping recovery processes

International Nuclear Information System (INIS)

Norman, J.C.; Sell, N.J.; Ciriacks, J.C.

1990-01-01

This paper reports that one of the current trends in paper-making with cellulose pulping is the use of high-yield processes. With yields greater than 65%, these processes include mechanical pulps (groundwood and thermomechanical pulps or TMP), and semichemical types (chemi-TMP or CTMP). Groundwood and TMP make up about 10% of North American pulp production. Semichemical pulp makes up about 7% and is mostly used for corrugating medium. High-yield pulping for linerboard, particularly using the alkaline sulfite process, is also likely to be used in the future. High-yield pulping is based primarily on the sulfite process using mostly sodium-based chemicals. A disadvantage of this process is the unavailability of a recovery system for the inorganic pulping chemicals. Generally, mills have not accepted any particular recovery system for this process. For this and other reasons, sulfite processes constitute only 3-4% of the total North American pulp production. If high-yield processes continue to increase in popularity, a sodium sulfite chemical recovery system will be needed. A number of chemical recovery systems have been developed in the past 30 years for sodium-based sulfite pulping processes, with most of the mills successfully using this process located in Scandinavia

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

Science.gov (United States)

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

2015-01-01

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

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)

Properties of nanocellulose isolated from corncob residue using sulfuric acid, formic acid, oxidative and mechanical methods.

Science.gov (United States)

Liu, Chao; Li, Bin; Du, Haishun; Lv, Dong; Zhang, Yuedong; Yu, Guang; Mu, Xindong; Peng, Hui

2016-10-20

In this work, nanocellulose was extracted from bleached corncob residue (CCR), an underutilized lignocellulose waste from furfural industry, using four different methods (i.e. sulfuric acid hydrolysis, formic acid (FA) hydrolysis, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation, and pulp refining, respectively). The self-assembled structure, morphology, dimension, crystallinity, chemical structure and thermal stability of prepared nanocellulose were investigated. FA hydrolysis produced longer cellulose nanocrystals (CNCs) than the one obtained by sulfuric acid hydrolysis, and resulted in high crystallinity and thermal stability due to its preferential degradation of amorphous cellulose and lignin. The cellulose nanofibrils (CNFs) with fine and individualized structure could be isolated by TEMPO-mediated oxidation. In comparison with other nanocellulose products, the intensive pulp refining led to the CNFs with the longest length and the thickest diameter. This comparative study can help to provide an insight into the utilization of CCR as a potential source for nanocellulose production. Copyright © 2016 Elsevier Ltd. All rights reserved.

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...

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

African Journals Online (AJOL)

Log in or Register to get access to full text downloads. ... obtained from Sappi Saiccor (formerly South African Industrial Cellulose Corporation) dissolving pulp mill ... were identified in the electro-oxidised reaction mixtures using gas chromatography-mass spectrometry ... EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT

Extraction and characterization of cellulose microfibrils from agricultural residue –Cocos nucifera L

International Nuclear Information System (INIS)

Uma Maheswari, C.; Obi Reddy, K.; Muzenda, E.; Guduri, B.R.; Varada Rajulu, A.

2012-01-01

The aim of this study was to extract cellulose microfibrils from the agricultural residue of coconut palm leaf sheath using chlorination and alkaline extraction process. Chemical characterization of the cellulose microfibrils confirmed that the α-cellulose mass fraction increased from 0.373 kg kg −1 to 0.896 kg kg −1 after application of several treatments including dewaxing, chlorite delignification and alkaline extraction of hemicelluloses. Similarly, the crystallinity index obtained from X-ray diffraction for leaf sheath and extracted cellulose microfibrils was found to be 42.3 and 47.7 respectively. The morphology of the cellulose microfibrils was investigated by scanning electron microscopy. The cellulose microfibrils had diameters in the range of 10–15 μm. Fourier transform infrared and Nuclear magnetic resonance spectroscopy showed that the chemical treatments removed most of the hemicellulose and lignin from the leaf sheath fibers. The thermal stability of the fibers was analyzed using thermogravimetric analysis, which demonstrated that this thermal stability was enhanced noticeably for cellulose microfibrils. This work provides a new approach for more effective utilization of coconut palm leaf sheaths to examine their potential use as pulp and paper and reinforcement fibers in biocomposite applications. -- Highlights: ► Utilization of Coconut palm leaf sheath as an alternate material for cellulose extraction. ► Using an abundant natural waste for paper pulp, biofilms and composite applications. ► Cellulose microfibrils have higher cellulose content than the leaf sheath. ► FTIR and NMR were used to study fiber structural changes during several treatments. ► Thermal stability of microfibrils is higher than their respective leaf sheath.

A comparative study on cellulose nanocrystals extracted from bleached cotton and flax and used for casting films with glycerol and sorbitol plasticisers.

Science.gov (United States)

Csiszár, Emilia; Nagy, Sebestyén

2017-10-15

Cellulose nanocrystals (CNCs) were released from bleached cotton and flax by a sulphuric acid hydrolysis with about 40 and 34% yield, respectively. The rod-like cotton-CNC particles were slightly longer and wider and had a less pronounced aggregation ability in aqueous suspension than the flax-CNC ones. Films were cast from the CNC suspensions with sorbitol and glycerol plasticisers. The concept behind this research was to explore how the plasticisers - with similar structure but different molecular weight - and their concentrations affect the perceptible and measured properties of CNC films. Results revealed that the type of plasticiser determined the morphology and the optical and tensile properties of films. The best quality CNC film with an averaged thickness of 50μm was obtained with 20% sorbitol from cotton-CNC. It was proved that behaviour of sorbitol and glycerol plasticisers in CNC films was very similar to that reported previously for starch films. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

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

2016-07-01

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

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

DEFF Research Database (Denmark)

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

2009-01-01

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

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.

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

International Nuclear Information System (INIS)

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

2013-01-01

Citrus peel is one of the under-utilized waste materials that have potential in producing a valuable fibre, which are cellulose and cellulose nanocrystal. Cellulose was first isolated from pomelo (C. Grandis Osbeck) albedo by combination of alkali treatment and bleaching process, followed by acid hydrolysis (65% H 2 SO 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

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

International Nuclear Information System (INIS)

Teodoro, Kelcilene B.R.; Teixeira, Eliangela de Morais; Correa, Ana Carolina; Campos, Adriana de; Marconcini, Jose Manoel; Mattoso, Luiz Henrique Capparelli

2011-01-01

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)

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

Science.gov (United States)

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

2008-04-01

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

Fracture resistance of teeth submitted to several internal bleaching protocols.

Science.gov (United States)

Leonardo, Renato de Toledo; Kuga, Milton Carlos; Guiotti, Flávia Angélica; Andolfatto, Carolina; Faria-Júnior, Norberto Batista de; Campos, Edson Alves de; Keine, Kátia Cristina; Dantas, Andrea Abi Rached

2014-03-01

The aim of this study was to evaluate the fracture resistance of teeth submitted to several internal bleaching protocols using 35% hydrogen peroxide (35HP), 37% carbamide peroxide (37CP), 15% hydrogen peroxide with titanium dioxide nanoparticles (15HPTiO2) photoactivated by LED-laser or sodium perborate (SP). After endodontic treatment, fifty bovine extracted teeth were divided into five groups (n = 10): G1-unbleached; G2-35HP; G3-37CP; G4-15HPTiO2 photoactivated by LED-laser and G5-SP. In the G2 and G4, the bleaching protocol was applied in 4 sessions, with 7 days intervals between each session. In the G3 and G5, the materials were kept in the pulp teeth for 21 days, but replaced every 7 days. After 21 days, the teeth were subjected to compressive load at a cross head speed of 0.5 mm/min, applied at 135° to the long axis of the root using an eletromechanical testing machine, until teeth fracture. The data were submitted to ANOVA and Tukey tests (α = 5%). The 35HP, 37CP, 15HPTiO2 and SP showed similar fracture resistance teeth reduction (p > 0.05). All bleaching treatments reduced the fracture resistance compared to unbleached teeth (p endodontically-treated teeth, but there were no differences between each other. There are several internal bleaching protocols using hydrogen peroxide in different concentrations and activation methods. This study evaluated its effects on fracture resistance in endodontically-treated teeth.

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.

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.).

ESR study of the radiolysis of cellobiose, cellulose-containing materials, and their mixtures with methyl methacrylate

International Nuclear Information System (INIS)

Kozlova, E.Y.; Shostenko, A.G.; Ermolaev, S.V.

1995-01-01

The ESR spectra of γ-irradiated cellobiose, paper waste, and cellulose extracted from paper waste and waste pulp sludge were analyzed. The kinetics of formation and decay of cellobiose radicals were investigated, and the radiation-chemical yields of the radicals formed in cellulose-containing materials were calculated. The ESR spectra of cellobiose irradiated in the presence of methyl methacrylate (MMA) were obtained. A probable mechanism of MMA grafting onto cellulose-containing matrices is considered

Transparent and Printable Regenerated Kenaf Cellulose/PVA Film

Directory of Open Access Journals (Sweden)

Hatika Kaco

2014-02-01

Full Text Available Cellulose was extracted from kenaf core powder by a series of bleaching processes and subsequently dissolved using an alkaline LiOH/urea solvent at low temperatures. The produced cellulose solution was mixed with polyvinyl alcohol (PVA with different ratios of cellulose/PVA and coagulated to produce regenerated transparent films. The films were then air dried to produce transparent film. The effects of PVA content on tensile index, transparency, pore size, and printability of the films were studied. A slight reduction of 7% on the tensile index of the film was observed when the content of PVA increased to 10%. Nevertheless, the addition of 10% of PVA increased the porosity of the regenerated cellulose/PVA film, while the transparency of the film increased by 10%. The films were color-printed using a laser printer and can be recycled, in which the printed ink can be removed easily from the films with higher amount of PVA content. In addition, the films can be reprinted repeatedly several times.

Method for Forming Pulp Fibre Yarns Developed by a Design-driven Process

Directory of Open Access Journals (Sweden)

Tiia-Maria Tenhunen

2016-01-01

Full Text Available A simple and inexpensive method for producing water-stable pulp fibre yarns using a deep eutectic mixture composed of choline chloride and urea (ChCl/urea was developed in this work. Deep eutectic solvents (DESs are eutectic mixtures consisting of two or more components that together have a lower melting point than the individual components. DESs have been previously studied with respect to cellulose dissolution, functionalisation, and pre-treatment. This new method uses a mixture of choline chloride and urea, which is used as a swelling and dispersing agent for the pulp fibres in the yarn-forming process. Although the pulp seemed to form a gel when dispersed in ChCl/urea, the ultrastructure of the pulp was not affected. To enable water stability, pulp fibres were crosslinked by esterification using polyacrylic acid. ChCl/urea could be easily recycled and reused by distillation. The novel process described in this study enables utilisation of pulp fibres in textile production without modification or dissolution and shortening of the textile value chain. An interdisciplinary approach was used, where potential applications were explored simultaneously with material development from process development to the early phase prototyping.

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.

Preparation and characterization of nanocomposites of the carboxymethyl cellulose reinforced with cellulose nanocrystals

International Nuclear Information System (INIS)

Flauzino Neto, Wilson P.; Silverio, Hudson A.; Vieira, Julia G.; Silva, Heden C.; Rosa, Joyce R.; Pasquini, Daniel; Assuncao, Rosana M.N.

2011-01-01

Nanocrystals of cellulose (NCC) isolated from Eucalyptus urograndis Kraft pulp were used to prepare nanocomposites employing carboxymethyl cellulose (CMC) as matrix. The nanocrystals were isolated by hydrolysis with H 2 SO 4 64% solution, for 20 minutes at 45 deg C. The nanocrystals were characterized by X-ray diffraction to evaluate the crystallinity of them. The amount of NCC used in the preparation of nanocomposites varied from 0 to 15%. The nanocomposites were characterized by thermal and mechanical analysis. A large reinforcing effect of NCC on the CMC matrix was observed. With the incorporation of the NCC, the tensile strength of nanocomposites was significantly improved by 107%, the elongation at break decreased by 48% and heat resistance to decomposition increased subtle. The improvement in thermo-mechanical properties are attributed to strong interactions between nanoparticles and CMC matrix. (author)

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

Construction materials as a waste management solution for cellulose sludge

International Nuclear Information System (INIS)

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

2011-01-01

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.

EFFECTIVITY OF TWO BLEACHING AGENT OF 10% CARBAMIDE PEROXIDE WITH AND WITHOUT POTASSIUM NITRATE-FLUORIDE (CLINICAL STUDY

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Ayus Lusiyanti

2015-06-01

Full Text Available Tooth bleaching has become a popular treatment for esthetic improvement in dentistry. There are several 10% carbamide peroxide bleaching agents that are available in Indonesia which contained potassium nitrate-fluoride or without potassium nitrate-fluoride. However, there was no clinical report about these products in Indonesia. This study was conducted to compare the effectiveness of two bleaching and sensitivity of tooth and gingiva. Sixty-four participants were divided into 2 groups. The first group was treated with bleaching agent that contained potassium nitrate-fluoride (Opalescence PF, Ultradent. Bleaching treatment was done for 6-8 hours per night over a 2 week-period. Evaluations were performed at the baseline and at 3, 7, 14 day afterwards. Color change was measured using a value-ordered Vita classic shade guide; tooth and gingival sensitivity were examine using Electric Pulp Tester, Gingival Index and patient log. The results showed that there were no statistical differences in degree of color change between the two products. The mean color change after 2 weeks was 7-8 tabs lighter than baseline. Also there was no statistical difference in tooth and gingival sensitivity between the products. It can be concluded that 10% carbamide peroxide containing potassium nitrate-fluoride has the same effectiveness compared to other agent without potassium nitrate-fluoride for tooth color change and tooth and gingival sensitivity.

Extraction of cellulose microcrystalline from galam wood for biopolymer

Science.gov (United States)

Ismail, Ika; Sa'adiyah, Devy; Rahajeng, Putri; Suprayitno, Abdi; Andiana, Rocky

2018-04-01

Consumption of plastic raw materials tends to increase, but until now the meet of the consumption of plastic raw are still low, even some are still imported. Nowadays, Indonesia's plastic needs are supported by petrochemicals where raw materials are still dependent abroad and petropolymer raw materials are derived from petroleum which will soon be depleted due to rising petroleum needs. Therefore, various studies have been conducted to develop natural fiber-based polymers that are biodegradable and abundant in nature. It is because the natural polymer production process is very efficient and very environmentally friendly. There have been many studies of biopolymers especially natural fiber-based polymers from plants, due to plants containing cellulose, hemicellulose and lignin. However, cellulose is the only one who has crystalline structures. Cellulose has a high crystality compared to amorphous lignin and hemicellulose. In this study, extracted cellulose as biopolymer and amplifier on composite. The cellulose is extracted from galam wood from East Kalimantan. Cellulose extraction will be obtained in nano / micro form through chemical and mechanical treatment processes. The chemical treatment of cellulose extraction is alkalinization process using NaOH solution, bleaching using NaClO2 and acid hydrolysis using sulfuric acid. After chemical treatment, ultrasonic mechanical treatment is made to make cellulose fibers into micro or nano size. Besides, cellulose results will be characterized. Characterization was performed to analyze molecules of cellulose compounds extracted from plants using Fourier Transformation Infra Red (FTIR) testing. XRD testing to analyze cellulose crystallinity. Scanning Electron Microscope (SEM) test to analyze morphology and fiber size.

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.

Potassium methyl siliconate-treated pulp fibers and their effects on wood plastic composites: Water sorption and dimensional stability

Science.gov (United States)

Cheng Piao; Zhiyong Cai; Nicole M. Stark; Charles J. Monlezun

2013-01-01

Potassium methyl siliconate (PMS) was investigated as a new nano modifier of wood fiber and wood flour to improve the compatibility between the fiber/flour and the plastic matrix in fiber reinforced plastic composites. Before injection molding, bleached and brown pulp fibers and mixed species wood flour were pretreated in PMS solutions. The morphology of the treated...

Physical properties of sago starch biocomposite filled with Nanocrystalline Cellulose (NCC) from rattan biomass: the effect of filler loading and co-plasticizer addition

Science.gov (United States)

Nasution, H.; Harahap, H.; Fath, M. T. Al; Afandy, Y.

2018-02-01

Rattan biomass is an abundant bioresources from processing industry of rattan which contains 37.6% cellulose. The high cellulose contents of rattan biomass make it a source of nanocrystalline cellulose as a filler in biocomposites. Isolation of alpha cellulose from rattan biomass was being prepared by using three stages: delignification, alkalization, and bleaching. It was delignificated with 3.5% HNO3 and NaNO2, precipitated with 17.5% NaOH, bleaching process with 10% H2O2. Nanocrystal obtained through the hydrolysis of alpha cellulose using 45% H2SO4 and followed by mechanical steps of ultrasonication, centrifugation, and filtration with a dialysis membrane. Biocomposite was being prepared by using a solution casting method, which includes 1-4 wt% nanocrystalline cellulose from rattan biomass as fillers, 10-40 wt% acetic acid as co-plasticizer and 30 wt% glycerol as plasticizer. The biocomposite characteristic consists of density, water absorption, and water vapors transmission rate. The results showed the highest density values was 0.266 gram/cm3 obtained at an additional of 3 wt% nanocrystalline cellulose from rattan biomass and 30 wt% acetic acid. The lowest water absorption was 9.37% at an additional of 3 wt% nanocrystalline cellulose from rattan biomass and 10 wt% acetic acid. It was observed by the addition of nanocrystalline cellulose might also decrease the rate of water vapor transmission that compared to the non-filler biocomposite.

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

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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.

Supra-molecular structure and chemical reactivity of cellulose I studied using CP/MAS (sup)13 C-NMR

CSIR Research Space (South Africa)

Chunilall, Viren

2013-08-01

Full Text Available There are a few traditional methods of analysing the chemical properties of cellulose I. Some of these methods include the Permanganate number determination, which is used to obtain the lignin content of the pulp [12]. The acid insoluble lignin content... – Fundamental Aspects 88 [10] Fengel D, Wegener G. Wood Chemistry, Ultrastructure, Reactions, Walter de Gruyter; 1984. [11] Uhlmann T. Ullmann's encyclopedia of industrial chemistry. Paper and Pulp. 1991; 18 (A). [12] Permanganate number of pulp, Tappi T...

Pulping and papermaking properties of the leaf fiber and fibrous residue from Agave tequilana

Energy Technology Data Exchange (ETDEWEB)

Kurita, T.; Mitsuhashi, S.; Kanetsuna, H.; Iguchi, M.; Shirota, T.; Trujillo, J.J.; Herrera, T.

1981-01-01

The leaves and fibrous residue of A. tequilana had fibriles with parallel orientation and helical arrangement to the fiber axis and contained fibers in average length and width of 1.7 mm and 10.3 mu m and 0.8 mm and 25.5 mu m, respectively. The cell wall in leaves was thicker and narrower than those in fibrous residue, and leaves contained cellulose and lignin lower than fibrous residue did. Alkali sulfite cooking of leaves gave pulp, the yield of which was lower than that from fibrous residue. The H/sub 2/On retention and bulk density of leaf pulps increased rapidly on beating suggesting that an internal fibrillation in pulp occurs easily during beating. The breaking length and burst and tear factors of paper from leaf pulp were higher than those from fibrous residue.

Biodegradable Composite Films based on κ-carrageenan Reinforced by Cellulose Nanocrystal from Kenaf Fibers

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Siti Zarina

2014-11-01

Full Text Available Through alkali treatment, bleaching, and sulfuric acid hydrolysis, cellulose nanocrystals (CNCs were prepared from kenaf fibers and were used as reinforcement materials in biocomposites based on κ-carrageenan. Biocomposites in the form of films were prepared by solution casting of a mixture of κ-carrageenan, glycerol, and various amounts of CNCs (0 to 8 wt%. Fourier transform infrared spectroscopy (FTIR revealed that alkali treatment followed by bleaching totally removed lignin and hemicellulose from the kenaf. Morphological analysis of the fibers, cellulose, and κ-carrageenan of biocomposite films were carried out using field emission scanning electron microscopy (FESEM and transmission electron microscopy (TEM. The effects of filler content on the mechanical and thermal stability of the k-carrageenan biocomposite films were analyzed through tensile strength measurements and thermogravimetric analysis (TGA. At an optimum CNC content of 4%, the κ-carrageenan biocomposite films showed good dispersion, superior mechanical properties, and improved thermal stability.

Utilization of agricultural cellulose wastes

Energy Technology Data Exchange (ETDEWEB)

Valkanas, G N; Economidis, D G; Koukios, E G; Valkanas, C G

1977-05-05

Wastes, example, straw, are prehydrolyzed to convert pentosanes, starches, and hemicelluloses to monosaccharides; the remaining pulp is 50% cellulose. Thus, dry wheat straw 0.8 kg was treated with 10 L of 0.3% aqueous HCl at 5-5.5 atm and 145/sup 0/ and a space velocity of 0.55 L/min, washed with dry steam, followed by water at 120 to 130/sup 0/, and more dry steam, and compressed at 25 kg/cm/sup 2/ to yield a product containing 45 to 50 wt % water. The sugar solution obtained (1394 L) contained 1.34 wt % reducing sugars, a straw hydrolysis of 23 wt %, and comprised xylose 74.3, mannose 5.2, arabinose 11.8, glucose 5.9, galactose 2.9%, and furfural 0.16 g/L. The cellulose residue had a dry weight of 0.545 kg. a yield of 68.2 wt % and contained cellulose 53.1, hemicelluloses 12.6%, lignin 22.1, ash and extractables 12.2%. The degree of polymerization was 805 glucose units.

Microhardness of demineralized enamel following home bleaching and laser-assisted in office bleaching

Science.gov (United States)

Ghanbarzadeh, Majid; Akbari, Majid; Hamzei, Haniye

2015-01-01

Background There is little data regarding the effect of tooth whitening on microhardness of white spot lesions. This study was conducted to investigate the effect of home-bleaching and laser-assisted in-office bleaching on microhardness of demineralized enamel. Material and Methods Forty bovine incisors were selected and immersed in a demineralizing solution for 12 weeks to induce white spot lesions. Enamel blocks were prepared and randomly assigned to two groups of 20 each. The first group underwent home bleaching with 15% carbamide peroxide which was applied for 8 hours a day over a period of 15 days. In the second group, in-office bleaching was performed by 40% hydrogen peroxide and powered by irradiation from an 810 nm gallium-aluminum-arsenide (GaAlAs) diode laser (CW, 2W). This process was performed for 3 sessions every seven days, in 15 days. The specimens were stored in Fusayama Meyer artificial saliva during the experiment. Surface microhardness was assessed before and after the bleaching therapies in both groups. Results Microhardness decreased significantly following both home bleaching and laser-assisted in-office bleaching (pTooth whitening through home bleaching or laser-assisted in-office bleaching can result in a significant reduction in microhardness of white spot lesions. Therefore, it is suggested to take protective measures on bleached demineralized enamel. Key words:White spot lesion, bleaching, laser, microhardness, demineralized enamel, home bleaching, in-office bleaching. PMID:26330939

Comparison of Cellulose Supramolecular Structures Between Nanocrystals of Different Origins

Science.gov (United States)

Umesh P. Agarwal; Richard S. Reiner; Christopher G. Hunt; Jeffery Catchmark; E. Johan Foster; Akira Isogai

2015-01-01

In this study, morphologies and supramolecular structures of CNCs from wood-pulp, cotton, bacteria, tunicate, and cladophora were investigated. TEM was used to study the morphological aspects of the nanocrystals whereas Raman spectroscopy provided information on the cellulose molecular structure and its organization within a CNC. Dimensional differences between the...

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

Science.gov (United States)

Ghasemi, Somayeh; Behrooz, Rabi; Ghasemi, Ismail

2016-06-01

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

Contents of constituents and antioxidant activity of seed and pulp extracts of Annona coriacea and Annona sylvatica

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RSR. Benites

Full Text Available AbstractThe antioxidant potential of fruit pulp and seeds of extracts of the Annona coriacea, and A. sylvatica(Annonaceae were investigated, as well contents total phenolics, flavonoids, condensed tannins and ascorbic acid. Was used to determine the antioxidant activity the 1,1-diphenyl-1-picrylhydrazyl free radical (DPPH, β-carotene bleaching and ABTS radical cation method. The total phenol, total flavonoid, condensed tannin, and ascorbic acid contents were measured spectrophotometrically. In this study, the pulp and seeds of the fruits were extracted using methanol/water (8:2 for maceration. The seed extracts of A. coriacea demonstrated a moderate antioxidant effect with free radical scavenging activity of 31.53%, by the DPPH test, 51.59% by the β-carotene bleaching test and 159.50 µM trolx/g of extract in the ABTS assay. We found that the hydromethanolic seed extract of A. coriacea had high total phenol (147.08 ± 4.20 mg of GAE/g of extract and flavonoid (131.18 ± 2.31 mg of QE/g of extract content. This indicated that the antioxidant activity of the extracts was related to the contents of these constituents.

A comparative evaluation of explosion hazards in chemical and mechanical pulp bleaching systems

Science.gov (United States)

Peter W. Hart; Alan W. Rudie

2010-01-01

Over the past several years, at least three pulp mills in North America have experienced catastrophic events that resulted in the explosion of pumps, mixers, and tanks. All these mills were using 50% concentration hydrogen peroxide at the site of the explosions. In at least two instances, alkali catalyzed decomposition of peroxide is implicated in the explosion....

THE PAPER CHARACTERISTICS FROM COMBINATION OF RICE HUSKS AND EMPTY FRUIT BUNCHES

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Yuli Ristianingsih

2017-10-01

Full Text Available Abstract- Rice husk and empty fruit bunches are agricultural and plantation wastes which have fiber cellulose and hemicellulose, it can be converted to pulp and paper. This research aims to study the effect of NaOH concentration (2, 4, 6 and 8% w/v and raw material composition to pulp yield and to study characteristics of the paper combination of rice husk and empty fruit bunches using soda process based on SEM and XRD analysis. This research using soda process because it is suitable for non-wood raw materials, low cost operations and not use sulfur compounds. Dry raw materials are mixed with NaOH and digesting using autoclave (100°C, 1 atm for 60 minutes. NaOH concentration optimum used in the pulping process a combination rice husk and empty fruit bunches (1:3, 1:2, 1:1, 2:1 and 3:1 and then cooled for 30 minutes. Pulp is bleached with NaClO 5.25% (v / v, then formed and dried as paper. The lowest pulp yield obtained in a ratio of 2: 1 is 27.6%. Based on the observation of SEM known the fiber of rice husk and empty fruit bunches is 5.88 to 9.8 μm and 8.82 to 14.71 μm, while based on XRD observations, chemical treatment can improve the characteristic of peak intensity on paper combination. The highest advances of peak intensity in the 1:3 ratio is 71.28% (cellulose I dan 83.33% (cellulose II.

THE PAPER CHARACTERISTICS FROM COMBINATION OF RICE HUSKS AND EMPTY FRUIT BUNCHES

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Yuli Ristianinsih

2017-10-01

Full Text Available Rice husk and empty fruit bunches are agricultural and plantation wastes which have fiber cellulose and hemicellulose, it can be converted to pulp and paper. This research aims to study the effect of NaOH concentration (2, 4, 6 and 8% w/v and raw material composition to pulp yield and to study characteristics of the paper combination of rice husk and empty fruit bunches using soda process based on SEM and XRD analysis. This research using soda process because it is suitable for non-wood raw materials, low cost operations and not use sulfur compounds. Dry raw materials are mixed with NaOH and digesting using autoclave (100°C, 1 atm for 60 minutes. NaOH concentration optimum used in the pulping process a combination rice husk and empty fruit bunches (1:3, 1:2, 1:1, 2:1 and 3:1 and then cooled for 30 minutes. Pulp is bleached with NaClO 5.25% (v / v, then formed and dried as paper. The lowest pulp yield obtained in a ratio of 2: 1 is 27.6%. Based on the observation of SEM known the fiber of rice husk and empty fruit bunches is 5.88 to 9.8 μm and 8.82 to 14.71 μm, while based on XRD observations, chemical treatment can improve the characteristic of peak intensity on paper combination. The highest advances of peak intensity in the 1:3 ratio is 71.28% (cellulose I dan 83.33% (cellulose II.

An investigation on the characteristics of cellulose nanocrystals from Pennisetum sinese

International Nuclear Information System (INIS)

Lu, Qi-lin; Tang, Li-rong; Wang, Siqun; Huang, Biao; Chen, Yan-dan; Chen, Xue-rong

2014-01-01

The aim of this study was to explore the utilization of Pennisetum sinese as cellulose source for the preparation of cellulose nanocrystals (CNC). The cellulose was extracted from P. sinese by chemical treatment and bleaching, and obtained cellulose nanocrystals by acid hydrolysis. Transmission electron microscopy (TEM) showed that CNC were rod-like with the diameter of 20–30 nm and the length of 200–300 nm. Fourier transform infrared (FTIR) showed that chemical treatment removed most of the lignin and hemicellulose from P. sinese, and CNC had similar structure to that of native cellulose. The crystallinity indexes calculated from X-ray diffraction (XRD) for P. sinese and CNC were 40.6% and 77.3%, respectively. The zeta-potential analysis showed that CNC had higher stability than P. sinese had. The thermal stability was investigated by thermogravimetric analysis (TGA), and the result showed that P. sinese had higher thermal stability than that of prepared CNC. - Highlights: • Pennisetum sinese Roxb is good raw material for preparing cellulose nanocrystals (CNC). • Crystallinity of prepared CNC is higher than that of P. sinese Roxb. • Thermal stability of prepared CNC is lower than that of P. sinese Roxb

Efficacy of cold light bleaching using different bleaching times and their effects on human enamel.

Science.gov (United States)

Wang, Wei; Zhu, Yuhe; Li, Jiajia; Liao, Susan; Ai, Hongjun

2013-01-01

This study investigated the efficacy of cold light bleaching using different bleaching times and the effects thereof on tooth enamel. Before and after bleaching, stained tooth specimens were subjected to visual and instrumental colorimetric assessments using Vita Shade Guide and spectrophotometric shade matching. Enamel surface alterations were examined using scanning electron microscopy (SEM) to analyze surface morphology, surface microhardness (SMH) measurement to determine changes in mechanical properties, and X-ray diffraction (XRD) to characterize post-bleaching enamel composition. Cold light bleaching successfully improved tooth color, with optimal efficacy when bleaching time was beyond 10 min. Significant differences in surface morphology were observed among the different bleaching times, but no significant differences were observed for enamel composition and surface microhardness among the different bleaching times. Results of this study revealed an association between the bleaching time of cold light bleaching and its whitening efficacy. Together with the results on enamel surface changes, this study provided positive evidence to support cold light bleaching as an in-office bleaching treatment.

Clean production of corn stover pulp using KOH+NH4OH solution and its kinetic during delignification

OpenAIRE

Sun Yong; Yang Gang; Zhang Jin-Ping; Yao Ming-Shun

2012-01-01

The self-made KOH together with NH4OH pulping of corn stover was investigated. The combined alkaline system could effectively remove lignin during pulping. There are three stages of lignin removal during delginification. Approximately 90% of lignin could be removed after temperature reached 150ºC for over 30 minutes. The p-hydroxyl phenol groups in lignin could be completely removed during the delignification reaction. The tendency of the increase of the crystalline degree of cellulose ...

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. Copyright © 2010 Elsevier Ltd. All rights reserved.

A colourimetric evaluation of the effect of bacterial contamination on teeth stained with blood in vitro: Evaluation of the efficacy of two different bleaching regimes.

Science.gov (United States)

Wang, S; Cathro, P; Heithersay, G; Briggs, N; Ratnayake, J; Zilm, P

2018-02-27

Tooth discolouration could occur due to bacterial contamination in traumatized teeth. Hydrogen peroxide is the commonly used bleaching agent. However, due to concerns over safety, alternative bleaching regimes such as sodium perborate (S) and thiourea-hydrogen peroxide (T) have been investigated. Apices resected and pulp extirpated 99 premolars were divided into two groups. Group 1 and 2 was injected with blood and blood/bacteria, stored anaerobically for 35 days. The two groups were treated by bleaching with water, S or T. Teeth were rebleached after 7 days. Colourimetric evaluation was assessed using digital imaging, CasMatch standardization and CIE L*a*b colour system preoperatively, 35 days of staining and 7 and 14 of bleaching. A linear mixed model with fixed effects of time, group and bleach was used to examine colour difference. Blood-stained teeth were significantly redder and darker on day 35 compared with blood/bacteria-stained teeth. After bleaching, blood-stained teeth retained significant redness compared with blood/bacteria-stained teeth using either S or T. T produced a significantly whiter shade in both the groups after 14 days. Blood-stained teeth were significantly darker and red compared with blood/bacteria-stained teeth. T bleaching regime was more effective than S. © 2018 Australian Dental Association.

AVALIAÇÃO DAS PROPRIEDADES FÍSICO-MECÂNICAS DE POLPAS PRODUZIDAS POR NOVAS SEQUÊNCIAS DE BRANQUEAMENTO

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Cristiane Pedrazzi

2010-01-01

Full Text Available The efficiency of oxygen delignification is very low for pulps of low number kappa and with high concentrations of hexenuronic acids, therefore the oxygen does not react with these acids, so being minimum the elimination of these during the oxygen delignification (pre-O2 in simple or double stage. In this study, the physicalmechanical properties of pulp of kappa number 17 and 14, produced with modified cooks and with the application of AD(EOD techniques for pulp of kappa 17 and DHT(EPODP for pulp of kappa 14 for the bleaching up to 90% ISO, had been investigated. The main objective of this study was to evaluate the physicalmechanical properties in pulps submitted to the bleaching sequences without oxygen in the beginning of the sequence. As references, cooks had been carried until numbers kappa 17 and 14, oxygen delignification and conventional bleaching for sequences A/D(EOD for pulp of kappa 17 and DHT(EPODP for pulp of kappa 14. The alternative bleaching, without pre-O2, resulted in bleached pulps with bigger integrity that of the reference, what it was confirmed by the values significantly higher of bulk, tear index, opacity and air resistance of the pulp weakly refined (for tissue papers. However, the high integrity of the fibers from pulps bleached with alternative processes lowered their conformabilities and collapsibility, with consequent reduction of tensile index of the pulp weakly refined. Therefore, with more intensive beating (for printing and writing papers, the tensile index was recovered. The high integrity of the bleaching pulps without pre-O2 makes beating difficulty. To reach the draining degree of 35°SR with the pulps proceeding from alternative processes of bleaching, it was necessary to apply 30% more energy than the reference.

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

International Nuclear Information System (INIS)

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

1980-01-01

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

Influence of homogenization treatment on physicochemical properties and enzymatic hydrolysis rate of pure cellulose fibers.

Science.gov (United States)

Jacquet, N; Vanderghem, C; Danthine, S; Blecker, C; Paquot, M

2013-02-01

The aim of this study is to compare the effect of different homogenization treatments on the physicochemical properties and the hydrolysis rate of a pure bleached cellulose. Results obtained show that homogenization treatments improve the enzymatic hydrolysis rate of the cellulose fibers by 25 to 100 %, depending of the homogenization treatment applied. Characterization of the samples showed also that homogenization had an impact on some physicochemical properties of the cellulose. For moderate treatment intensities (pressure below 500 b and degree of homogenization below 25), an increase of water retention values (WRV) that correlated to the increase of the hydrolysis rate was highlighted. Result also showed that the overall crystallinity of the cellulose properties appeared not to be impacted by the homogenization treatment. For higher treatment intensities, homogenized cellulose samples developed a stable tridimentional network that contributes to decrease cellulase mobility and slowdown the hydrolysis process.

The effect of oxyalkylation and application of polymer dispersions on the thermoformability and extensibility of paper.

Science.gov (United States)

Kouko, Jarmo; Setälä, Harri; Tanaka, Atsushi; Khakalo, Alexey; Ropponen, Jarmo; Retulainen, Elias

2018-04-15

Wood fiber-based packaging materials, as renewable materials, have growing market potential due to their sustainability. A new breakthrough in cellulose-based packaging requires some improvement in the mechanical properties of paper. Bleached softwood kraft pulp was mechanically treated, in two stages, using high- and low-consistency refining, sequentially. Chemical treatment of pulp using the oxyalkylation method was applied to modify a portion of fiber material, especially the fiber surface, and its compatibility with polymer dispersions including one carbohydrate polymer. The results showed that the compatibility of the cellulosic fibers with some polymers could be improved with oxyalkylation. By adjusting mechanical and chemical treatments, and the thermoforming conditions, the formability of paper was improved, but simultaneously the strength and stiffness decreased. The results suggest that the formability of the paper is not a direct function of the extensibility of the applied polymer, but also depends on the fiber network structure and surface energy. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Preliminary studies of the development of a direct compression cellulose excipient from bagasse.

Science.gov (United States)

Padmadisastra, Y; Gonda, I

1989-06-01

Bagasse is an unused by-product in cane sugar manufacture. Bagasse from sugar cane manually harvested in Indonesia was transformed to pulp by mechanical means and repeated autoclaving in 1.4% NaOH. It was then subjected to cycles of bleaching with hypochlorite and acid hydrolysis with 2.5 M HCl to produce 'microcrystalline' cellulose (MCC). Extraction of waxes by petroleum ether was necessary in order to improve the disintegration properties of tablets made from this material, DICEB III. When the bagasse-derived cellulose was reconstituted by recombining different proportions of selected sieve cuts to have a similar sieve size distribution as the commercially available MCC, Avicel PH102, it was found that the latter and DICEB III also had similar crystallinity as measured by X-ray powder diffraction (degree of crystallinity 2.8 +/- 0.2). The crystallinity and flow index were also relatively insensitive to most of the changes in the manufacturing procedure, indicating that the production process was quite robust. Directly compressed tablets were made containing 50 mg of caffeine and 500 mg of either Avicel PH102 or DICEB III to approximately the same hardness (11.6 +/- 1.1 and 13.7 +/- 0.5 kPa, respectively). They displayed similar satisfactory disintegration and dissolution behavior. However, DICEB III required greater compaction pressures than Avicel PH102, perhaps because the former was not spray dried to give spherical agglomerates of particles of uniform size as the commercial product. Rather, DICEB III consisted mainly of single irregular particles. Further work is required to improve the new excipient and to explore if the bagasse from mechanically harvested sugar cane (often contaminated by soil) could also be used for production of MCC.

Non-bleached colonies of massive Porites may attract fishes for selective grazing during mass bleaching events

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Eri Ikeuchi

2017-06-01

Full Text Available In this study we investigated the variation in grazing scar densities between bleached and non-bleached colonies of massive Porites species in Sekisei Lagoon (Okinawa, southwestern Japan during a mass bleaching event in 2016. The grazing scar densities and bleaching susceptibility varied among neighboring colonies of massive Porites spp. However, non-bleached colonies had significantly more surface scars than bleached colonies. One explanation for these variations is that corallivorous fishes may selectively graze on non-bleached, thermally tolerant colonies. This is the first report of a relationship between grazing scars and the bleaching status of massive Porites spp. colonies during a mass bleaching event.

Better together: synergy in nanocellulose blends

Science.gov (United States)

Mautner, Andreas; Mayer, Florian; Hervy, Martin; Lee, Koon-Yang; Bismarck, Alexander

2017-12-01

Cellulose nanopapers have gained significant attention in recent years as large-scale reinforcement for high-loading cellulose nanocomposites, substrates for printed electronics and filter nanopapers for water treatment. The mechanical properties of nanopapers are of fundamental importance for all these applications. Cellulose nanopapers can simply be prepared by filtering a suspension of nanocellulose, followed by heat consolidation. It was already demonstrated that the mechanical properties of cellulose nanopapers can be tailored by the fineness of the fibrils used or by modifying nanocellulose fibrils for instance by polymer adsorption, but nanocellulose blends remain underexplored. In this work, we show that the mechanical and physical properties of cellulose nanopapers can be tuned by creating nanopapers from blends of various grades of nanocellulose, i.e. (mechanically refined) bacterial cellulose or cellulose nanofibrils extracted from never-dried bleached softwood pulp by chemical and mechanical pre-treatments. We found that nanopapers made from blends of two or three nanocellulose grades show synergistic effects resulting in improved stiffness, strength, ductility, toughness and physical properties. This article is part of a discussion meeting issue `New horizons for cellulose nanotechnology'.

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...

Investigation on anatomical, chemical and pulping characteristics of Silybum marianum stem

Directory of Open Access Journals (Sweden)

Rahim Yadollahi

2013-11-01

Full Text Available To study the possibility of using plant Silybum marianum in paper industry, its stem yield potential, chemical properties, fiber indices and pulping was evaluated. Mean value of fiber length and diameter of Silybum marianumstem harvested in early June, were calculated 178 and 3.5 cm, respectively. Dry weight of whole stem determined 4710 kg per hectar. Mean value of fiber length, diameter, cavity diameter and wall thickness were obtained 1194, 16.06, 9.06, and 3.66 μm, respectively. Raunkel, flexibility, and slenderness ratios of its fibers were determined 80.83, 56.39, and 74.37, respectively. Results of chemical analysis showed that the stem comprises %70.35 holocellulose, %39.25 cellulose, %13.13 lignin, %3.09 acetone-soluble, %18 hot water-soluble extractives, and %11/85 ash. Soda pulp was obtained at 165 °C pulping time, 25% alkaline and 10:1 ratio of liquor to chips. Results of pulping showed that with increasing of pulping time from 30 to 210 minutes, the kappa number and yield decreased from 77.32 to 32.13 and 43.6 to 36.5, respectively; whereas accepted pulp yield (passed from 20 mesh increased from 17.4 to 35.5% paper made of pulp with kappa number 32 had 36.82 Nm/g tensile index, 3.76 km breaking length and 1.75 Kpa.m2/g burst strength. In general, achieved results have shown that the present studied species could be regarded more for papermaking because of the suitable fiber biometrical and chemical properties as compared to other non-woody plants.

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

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

Peroxy bleaches

Energy Technology Data Exchange (ETDEWEB)

Carson, P.A. [Unilever Research, Port Sunlight Laboratory (United States) and Chemistry Department, University of Manchester, Institute of Science and Technology (United States)]. E-mail: pcarson2005@aol.com; Fairclough, C.S. [Unilever Research, Port Sunlight Laboratory (United States); Mauduit, C. [Chemistry Department, University of Manchester, Institute of Science and Technology (United States); Colsell, M. [Chemistry Department, University of Manchester, Institute of Science and Technology (United States)

2006-08-25

Fabric laundering is now a sophisticated chemical process involving a variety of operations including bleaching. The chemistry of peroxy bleaches is described including the use of novel organic compounds to provide effective bleaching at the lower temperatures of modern wash cycles. The instability of peroxy compounds is illustrated using cameo case histories to relate theory and practice. Techniques available for determining their thermochemistry are summarised. A model is provided for hazard and risk assessment of development projects in general (particularly those involving new molecules, processes or formulations) from ideas phase through exploratory laboratory investigations to pilot plant scale-up and eventual manufacture and commercial exploitation. This paper is a prelude to Part 2, which describes the determination of thermodynamic and kinetic properties of peroxy bleaches and discusses the implication of the results in terms of precautions for their safe storage and incorporation into detergent formulations during processing.

Peroxy bleaches

International Nuclear Information System (INIS)

Carson, P.A.; Fairclough, C.S.; Mauduit, C.; Colsell, M.

2006-01-01

Fabric laundering is now a sophisticated chemical process involving a variety of operations including bleaching. The chemistry of peroxy bleaches is described including the use of novel organic compounds to provide effective bleaching at the lower temperatures of modern wash cycles. The instability of peroxy compounds is illustrated using cameo case histories to relate theory and practice. Techniques available for determining their thermochemistry are summarised. A model is provided for hazard and risk assessment of development projects in general (particularly those involving new molecules, processes or formulations) from ideas phase through exploratory laboratory investigations to pilot plant scale-up and eventual manufacture and commercial exploitation. This paper is a prelude to Part 2, which describes the determination of thermodynamic and kinetic properties of peroxy bleaches and discusses the implication of the results in terms of precautions for their safe storage and incorporation into detergent formulations during processing

Electrically aligned cellulose film for electro-active paper and its piezoelectricity

International Nuclear Information System (INIS)

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

2009-01-01

Electrically aligned regenerated cellulose films were fabricated and the effect of applied electric field was investigated for the piezoelectricity of electro-active paper (EAPap). The EAPap was fabricated by coating gold electrodes on both sides of regenerated cellulose film. The cellulose film was prepared by dissolving cotton pulp in LiCl/N,N-dimethylacetamide solution followed by a cellulose chain regeneration process. During the regeneration process an external electric field was applied in the direction of mechanical stretching. Alignment of cellulose fiber chains was investigated as a function of applied electric field. The material characteristics of the cellulose films were analyzed by using an x-ray diffractometer, a field emission scanning electron microscope and a high voltage electron microscope. The application of external electric fields was found to induce formation of nanofibers in the cellulose, resulting in an increase in the crystallinity index (CI) values. It was also found that samples with higher CI values showed higher in-plane piezoelectric constant, d 31 , values. The piezoelectricity of the current EAPap films was measured to be equivalent or better than that of ordinary PVDF films. Therefore, an external electric field applied to a cellulose film along with a mechanical stretching during the regeneration process can enhance the piezoelectricity. (technical note)

Comparative studies on anthraquinone retention following the soda/anthraquinone process using 14C-labelled anthraquinone, and mode of action of anthraquinone on lignins and lignin model components

International Nuclear Information System (INIS)

Pfuetze, E.

1982-01-01

This dissertation contributes to the clarification of the following questions: how much of the additive is retained in cellulose following soda/anthraquinone-wood pulping; how much anthraquinone can be detected after extraction studies and after a conventional CEHD-bleaching treatment; can differences be detected between soda lignins and soda/anthraquinone lignins with respect to analytical data, spectroscopie characteristics and macromolecular properties; and how do dimeric lignin models with #betta#-arylether structure behave in decomposition studies using the soda/anthraquinone process. (orig./MG) [de

Crown discoloration promoted by materials used in regenerative endodontic procedures and effect of dental bleaching: spectrophotometric analysis.

Science.gov (United States)

Santos, Luciane Geanini Pena Dos; Felippe, Wilson Tadeu; Souza, Beatriz Dulcineia Mendes de; Konrath, Andrea Cristina; Cordeiro, Mabel Mariela Rodríguez; Felippe, Mara Cristina Santos

2017-01-01

To assess tooth crown's color after intracanal treatment with triple antibiotic paste (TAP) or calcium hydroxide (CH); cervical sealing with glass ionomer cement (GIC) or mineral trioxide aggregate (MTA); and bleaching with carbamide peroxide. After pulp removal and color spectrophotometer measurement, 50 bovine incisors were divided into 4 experimental groups and one control (untreated). Experiments were performed in phases (Ph). Ph1: TAP (ciprofloxacin, metronidazole, minocycline), TAPM (ciprofloxacin, metronidazole, amoxicillin), DAP (ciprofloxacin, metronidazole), or CH treatment groups. After 1 and 3 days (d); 1, 2, 3 weeks (w); and 1, 2, 3 and 4 months (m), color was measured and medications were removed. Ph2: GIC or MTA cervical sealing, each using half of the specimens from each group. Color was assessed after 1d, 3d; 1w, 2w, 3w; 1m and 2m. Ph3: Two bleaching sessions, each followed by color measurement. Data were analyzed with ANOVA and post-hoc Holm-Sidak method. Ph1: Specimens of TAP group presented higher color alteration (ΔE) mean than those of TAPM group. No significant difference was found among TAP or TAPM and CH, DAP or Control groups. Ph2: cervical sealing materials showed no influence on color alteration. Ph3: Different ΔE means (from different groups), prior to bleaching, became equivalent after one bleaching session. TAP induces higher color alteration than TAPM; color alteration increases over time; cervical sealing material has no influence on color alteration; and, dental bleaching was able to recover, at least partially, the tooth crown's color.

Conversion of industrial (ligno)cellulose feeds to isosorbide with heteropoly acids and Ru on carbon

Energy Technology Data Exchange (ETDEWEB)

Op de Beeck, B.; Van Lishout, J.; Jacobs, P.A.; Sels, B.F. [Centre for Surface Chemistry and Catalysis, Katholieke Universiteit Leuven, Kasteelpark Arenberg 23, 3001 Heverlee (Belgium); Geboers, J. [Max-Planck-Institut fuer Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Muelheim an der Ruhr (Germany); Van de Vyver, S. [Massachusetts Institute of Technology MIT, Massachusetts Avenue 77, Cambridge, MA 02139-4307 (United States); Snelders, J.; Courtin, C.M. [Centre for Food and Microbial Technology, Katholieke Universiteit Leuven, Kasteelpark Arenberg 22, 3001 Heverlee (Belgium); Huijgen, W.J.J. [Biomass and Energy Efficiency BEE, Energy research Centre of the Netherlands ECN, Westerduinweg 3, 1755 LE Petten (Netherlands)

2013-01-11

The catalytic valorization of cellulose is currently subject of intense research. Isosorbide is among the most interesting products that can be formed from cellulose as it is a potential platform molecule and can be used for the synthesis of a wide range of pharmaceuticals, chemicals, and polymers. A promising direct route from cellulose to isosorbide is presented in this work. The strategy relies on a one-pot bifunctional catalytic concept, combining heteropoly acids, viz. H4SiW12O40, and redox catalysts, viz. commercial Ru on carbon, under H2 pressure. Starting from pure microcrystalline cellulose, a rapid conversion was observed, resulting in over 50% isosorbide yield. The robustness of the developed system is evidenced by the conversion of a range of impure cellulose pulps obtained by organosolv fractionation, with isosorbide yields up to 63%. Results were compared with other (ligno)cellulose feedstocks, highlighting the importance of fractionation and purification to increase reactivity and convertibility of the cellulose feedstock.

Final Technical Report Steam Cycle Washer for Unbleached Pulp

Energy Technology Data Exchange (ETDEWEB)

Starkey, Yvonne; Salminen, Reijo; Karlsnes, Andy

2008-09-22

through the pulping phases. Most water used in the pulping process ends up as warm waste water in the mill’s effluent discharge, which subsequently pollutes receiving waterways and carries an enormous amount of energy with it. Wash water reduction in brown stock washing with the Steam Cycle Washers (SCW) will save energy, up to 1+ million BTUs per ton of pulp in the evaporators alone. Reduction of liquid volume through bleaching stages will save process heat energy in the amount of 2+ million BTUs per ton of pulp, and as much as 80 – 100 kWhrs of electrical power per ton of pulp due to reduced pumping costs. Currently, the technical barriers to water reduction in chemical pulping are basically as follows: • conventional pulp washers wash the pulp at 10 - 14% consistency, • conventional pulp washers use 12 – 16 tons of wash water per ton of pulp, and • they leave 30 – 70 lbs of soda (Na2SO4) per ton of pulp as soda loss into the washed pulp. The amount of wash water in excess of the amount of process liquid in the pulp is called Dilution Factor (DF), even though it is not a factor in the mathematical sense but an addition. Modern pulp washing lines can wash efficiently with a DF of 3 but most pulp mills in the United States are washing with a DF of 5-7. Therefore, at 10% washing consistency 14-16 tons of wash water is required and 14% consistency requires 11-13 tons of wash water.

FT-Raman spectra of cellulose and lignocellulose materials : “self-absorption” phenomenon and its implications for quantitative work

Science.gov (United States)

Umesh Agarwal; Nancy Kawai

2003-01-01

The phenomenon of “self-absorption” was found to exist in the FT-Raman spectra of cellulose and thermomechanical pulp (TMP), but not in the spectrum of milled wood lignin. For cellulose and TMP, the effect was responsible for reducing the intensity of the Raman bands in the C-H stretch region. Several factors including sampling position, sample thickness, and moisture...

Preparation and Characterization of Cellulose and Nanocellulose from Agro-industrial Waste - Cassava Peel

Science.gov (United States)

Widiarto, S.; Yuwono, S. D.; Rochliadi, A.; Arcana, I. M.

2017-02-01

Cassava peel is an agro-industrial waste which is available in huge quantities in Lampung Province of Indonesia. This work was conducted to evaluate the potential of cassava peel as a source of cellulose and nanocellulose. Cellulose was extracted from cassava peel by using different chemical treatment, and the nanocellulose was prepared by hydrolysis with the use of sulfuric acid. The best methods of cellulose extraction from cassava peels are using alkali treatment followed by a bleaching process. The cellulose yield from this methods was 17.8% of dry base cassava peel, while the yield from nitric and sulfuric methods were about 10.78% and 10.32% of dry base cassava peel respectively. The hydrolysis was performed at the temperature of 50 °C for 2 hours. The intermediate reaction product obtained after each stage of the treatments was characterized. Fourier transform infrared spectroscopy showed the removal of non-cellulosic constituent. X-ray Diffraction (XRD) analysis revealed that the crystallinity of cellulose increased after hydrolysis. Morphological investigation was performed using Scanning Electron Microscopy (SEM). The size of particle was confirmed by Particle Size Analyzer (PSA) and Transmission Electron Microscopy (TEM).

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)

[Vital pulp therapy of damaged dental pulp].

Science.gov (United States)

Xuedong, Zhou; Dingming, Huang; Jianguo, Liu; Zhengwei, Huang; Xin, Wei; Deqin, Yang; Jin, Zhao; Liming, Chen; Lin, Zhu; Yanhong, Li; Jiyao, Li

2017-08-01

The development of an expert consensus on vital pulp therapy can provide practical guidance for the improvement of pulp damage care in China. Dental pulp disease is a major type of illness that adversely affects human oral health. Pulp capping and pulpotomy are currently the main methods for vital pulp therapy. Along with the development of minimal invasion cosmetic dentistry, using different treatment technologies and materials reasonably, preserving healthy tooth tissue, and extending tooth save time have become urgent problems that call for immediate solution in dental clinics. This paper summarizes the experiences and knowledge of endodontic experts. We develop a clinical path of vital pulp therapy for clinical work by utilizing the nature, approach, and degree of pulp damage as references, defense and self-repairing ability of pulp as guidance, and modern technologies of diagnosis and treatment as means.

rendimento e qualidade de fibras secundárias

Directory of Open Access Journals (Sweden)

Gustavo Ventorim

2005-01-01

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

Bleaching of Wool with Sodium Borohydride

OpenAIRE

Duygu Yilmazer, MSc.; Mehmet Kanik, Ph.D.

2009-01-01

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

Air-Cured Fiber-Cement Composite Mixtures with Different Types of Cellulose Fibers

Directory of Open Access Journals (Sweden)

Ali Murat Soydan

2018-01-01

Full Text Available This present study was carried out to check the feasibility of different cellulose fibers obtained from cropped virgin cellulose, blenched eucalyptus, and araucaria pulps through different new environmentally friendly curing processes for fiber-cement production. The aim is to introduce the different sources of cellulose fibers with lower cost to produce the “fiber-cement without autoclave” (FCWA. The slurries used in the experiments contain approximately 8% wt. of cellulose. The influence of the waste marble powder addition to the cement mixture was also studied. The physical and mechanical properties of the products which were prepared with this method under different curing conditions were investigated. The mechanical properties of eucalyptus cellulose appear to offer the best combination, especially after longer air-cure cycles. The results showed that the production of FCWA is very economical by using waste marble powders. And moreover, two new types of cellulose fibers (eucalyptus and araucaria celluloses; EuC and ArC, resp., which provide a better density and packing in the fiber-cement leading to better modulus of rupture (MOR and modulus of elasticity (MOE values as virgin cellulose (ViC, are very usable for production of the fiber-cement in industrial scale.

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

Directory of Open Access Journals (Sweden)

Ida Vaskova,

2012-01-01

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

Opalescence of bleached teeth.

Science.gov (United States)

Schmeling, Max; Maia, Hamilton Pires; Baratieri, Luiz Narciso

2012-07-01

To evaluate the influence of tooth bleaching on the opalescence properties of enamel. Color of 38 specimens was determined by colorimetric analysis before and after bleaching in the reflectance and transmittance modes. The results were described as CIELab color coordinates. The Opalescent Parameter (OP) was calculated as the difference in yellow-blue color coordinate (CIE Δb*) and red-green color coordinate (CIE Δa*) between the reflected and transmitted colors. Mean OP value of the specimens was 18.9 (±1.6) before bleaching and 16.1 (±1.0) after bleaching. Bleaching decreases the OP of the specimens (p>0.001). OP decrease was correlated with differences in b* color coordinate in the transmittance mode. Copyright © 2012 Elsevier Ltd. All rights reserved.

Titanium dioxide–cellulose hybrid nanocomposite and its glucose biosensor application

International Nuclear Information System (INIS)

Maniruzzaman, Mohammad; Jang, Sang-Dong; Kim, Jaehwan

2012-01-01

Highlights: ► An organic–inorganic hybrid nanocomposite was fabricated by blending TiO 2 nanoparticles and cellulose solution. ► The hybrid nanocomposite has advantages of biodegradability and bio-compatibility of cellulose and physical properties of TiO 2 . ► Enzyme glucose oxidase (GOx) was immobilized into the hybrid nanocomposite and covalent bonding between TiO 2 and GOx was confirmed by X-ray photoelectron analysis. ► Linear response of the glucose biosensor was obtained in the range of 1–10 mM. - Abstract: This paper investigates the fabrication of titanium dioxide (TiO 2 )–cellulose hybrid nanocomposite and its possibility for a conductometric glucose biosensor. TiO 2 nanoparticles were blended with cellulose solution prepared by dissolving cotton pulp with lithium chloride/N,N-dimethylacetamide solvent to fabricate TiO 2 –cellulose hybrid nanocomposite. The enzyme, glucose oxidase (GOx) was immobilized into this hybrid nanocomposite by physical adsorption method. The successful immobilization of glucose oxidase into TiO 2 –cellulose hybrid nanocomposite via covalent bonding between TiO 2 and GOx was confirmed by X-ray photoelectron analysis. The linear response of the glucose biosensor is obtained in the range of 1–10 mM. This study demonstrates that TiO 2 –cellulose hybrid nanocomposite can be a potential candidate for an inexpensive, flexible and disposable glucose biosensor.

Autohydrolysis processing as an alternative to enhance cellulose solubility and preparation of its regenerated bio-based materials

Energy Technology Data Exchange (ETDEWEB)

Gan, Sinyee, E-mail: gansinyee@hotmail.com; Zakaria, Sarani, E-mail: szakaria@ukm.edu.my; Chen, Ruey Shan; Chia, Chin Hua; Padzil, Farah Nadia Mohammad; Moosavi, Seyedehmaryam

2017-05-01

Kenaf core pulp has been successfully autohydrolysed using an autoclave heated in oil bath at various reaction temperature at 100, 120 and 140 °C. Membranes, hydrogels and aerogels were then prepared from autohydrolysed kenaf in urea/alkaline medium by casting on the glass plate, by using epichlorohydrin (ECH) as cross-linker via stirring and freeze-drying method, respectively. The autohydrolysis process reduced the molecular weight of cellulose and enhanced cellulose solubility and viscosity. Structure and properties of the regenerated products were measured with Field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), Ultraviolet–visible (UV–Vis) spectrophotometer and swelling testing. As the autohydrolysis temperature increased, the porosity of cellulose membranes (as seen from the morphology) increased. The autohydrolysis process improved the swelling porperties and transparency of regenerated cellulose hydrogels. This finding is expected to be useful in reducing molecular weight of cellulose in order to produce regenerated bio-based cellulose materials. - Highlights: • Autohydrolysis temperature is negatively correlated to cellulose molecular weight. • Cellulose solubility and viscosity are improved after cellulose pretreatment. • Autohydrolysis improved the properties of regenerated cellulose materials.

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

Red algae and their use in papermaking.

Science.gov (United States)

Seo, Yung-Bum; Lee, Youn-Woo; Lee, Chun-Han; You, Hack-Chul

2010-04-01

Gelidialian red algae, that contain rhizoidal filaments, except the family Gelidiellaceae were processed to make bleached pulps, which can be used as raw materials for papermaking. Red algae consist of rhizoidal filaments, cortical cells usually reddish in color, and medullary cells filled with mucilaginous carbohydrates. Red algae pulp consists of mostly rhizoidal filaments. Red algae pulp of high brightness can be produced by extracting mucilaginous carbohydrates after heating the algae in an aqueous medium and subsequently treating the extracted with bleaching chemicals. In this study, we prepared paper samples from bleached pulps obtained from two red algae species (Gelidium amansii and Gelidium corneum) and compared their properties to those of bleached wood chemical pulps. Copyright 2009 Elsevier Ltd. All rights reserved.

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

Enzymatic hydrolysis of cellulose dissolved in N-methyl morpholine oxide/water solutions.

Science.gov (United States)

Ramakrishnan, S; Collier, J; Oyetunji, R; Stutts, B; Burnett, R

2010-07-01

In situ hydrolysis of cellulose (dissolving pulp) in N-methyl morpholine oxide (NMMO) solutions by commercially available Accellerase1000 is carried out. The yield of reducing sugars is followed as a function of time at three different temperatures and four different enzyme loadings to study the effect of system parameters on enzymatic hydrolysis. Initial results show that rates of hydrolysis of cellulose and yields of reducing sugars in the presence of NMMO-water is superior initially (ratio of initial reaction rates approximately 4) and comparable to that of regenerated cellulose (for times greater than 5h) when suspended in aqueous solutions. The usage of Accellerase1000 results predominantly in the formation of glucose with minimal amounts of cellobiose. This study proves the ability of cellulases to remain active in NMMO to carry out an in situ saccharification of cellulose thus eliminating the need to recover regenerated cellulose. Thus this work will form the basis for developing a continuous process for conversion of biomass to hydrogen, ethanol and other hydrocarbons. Copyright 2009 Elsevier Ltd. All rights reserved.

Chemically-modified cellulose paper as a microstructured catalytic reactor.

Science.gov (United States)

Koga, Hirotaka; Kitaoka, Takuya; Isogai, Akira

2015-01-15

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.

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.

Body image disturbance and skin bleaching.

Science.gov (United States)

Charles, Christopher A D; McLean, Shua-Kym

2017-11-01

This study looks at body image disturbance among Jamaicans who bleach their skin. The hypothesis states that there is a positive relationship between skin bleaching and body image disturbance. The study used a convenience sample of 160 participants with a skin bleaching group (n = 80) and a non-bleaching comparison group (n = 80). The instrument included demographic questions, the body image disturbance questionnaire (BIDQ), and questions about skin bleaching. The results of a t-test revealed that the skin bleaching group (M = 1.5255, SD = 0.42169) was not significantly different from the non-bleaching group (M = 1.4938, SD = 0.74217) in terms of body image disturbance, t(158) = 0.333, p = .740. The participants who bleached did not suffer from body image disturbance. Self-reports revealed that they bleached to acquire beauty, attract a partner, elude the police, and market skin bleaching products. The practice was fashionable and popular and it made some participants feel good, while others were fans of a popular musical artiste who bleached his skin. The majority of participants bleached because of the perceived personal, social, and entrepreneurial benefits of the practice and not because they suffered emotional distress, anxiety, and functional impairment because of their skin colour. However, there was some level of BID among the minority of participants who argued that they bleached because they wanted to be pretty so they were emotionally distressed about there body image and experienced functional impairment. © 2017 The British Psychological Society.

Biotechnology of microbial xylanases: enzymology, molecular biology, and application.

Science.gov (United States)

Subramaniyan, S; Prema, P

2002-01-01

Xylanases are hydrolases depolymerizing the plant cell wall component xylan, the second most abundant polysaccharide. The molecular structure and hydrolytic pattern of xylanases have been reported extensively and the mechanism of hydrolysis has also been proposed. There are several models for the gene regulation of which this article could add to the wealth of knowledge. Future work on the application of these enzymes in the paper and pulp, food industry, in environmental science, that is, bio-fueling, effluent treatment, and agro-waste treatment, etc. require a complete understanding of the functional and genetic significance of the xylanases. However, the thrust area has been identified as the paper and pulp industry. The major problem in the field of paper bleaching is the removal of lignin and its derivatives, which are linked to cellulose and xylan. Xylanases are more suitable in the paper and pulp industry than lignin-degrading systems.

Bleaching and enamel surface interactions resulting from the use of highly-concentrated bleaching gels.

Science.gov (United States)

Grazioli, Guillermo; Valente, Lisia Lorea; Isolan, Cristina Pereira; Pinheiro, Helena Alves; Duarte, Camila Gonçalves; Münchow, Eliseu Aldrighi

2018-03-01

Tooth bleaching is considered a non-invasive treatment, although the use of highly-concentrated products may provoke increased surface roughness and enamel demineralization, as well as postoperative sensitivity. Thus, the aim of this study was to investigate whether hydrogen peroxide (H 2 O 2 ) concentration would affect tooth bleaching effectiveness and the enamel surface properties. Enamel/dentin bovine specimens (6 × 4 mm) were immersed in coffee solution for 7 days and evaluated with a spectrophotometer (Easyshade; baseline), using the CIEL * a * b * color parameters. Hardness was measured using a hardness tester. The specimens were randomly assigned into four groups: one negative control, in which the specimens were not bleached, but they were irradiated with a laser-light source (Whitening Lase II, DMC Equipments); and three groups using distinct H 2 O 2 concentration, namely LP15% (15% Lase Peroxide Lite), LP25% (25% Lase Peroxide Sensy), and LP35% (35% Lase Peroxide Sensy), all products from DMC. The bleached specimens were also irradiated with the laser-light source. After bleaching, all specimens were evaluated using scanning electron microscopy (SEM). pH kinetics and rate was monitored during bleaching. The data were analyzed using ANOVA and Tukey's test (p bleaching gels produced similar color change (p > 0.05). Concerning hardness, only the LP25% and LP35% significantly reduced hardness after bleaching; also, there was a progressive tendency for a greater percentage reduction in hardness with increased H 2 O 2 concentration of the gel (R 2  = 0.9973, p bleaching effectiveness, and may increase the possibility for alteration of enamel hardness, surface morphology, and acidity of the medium. When using H 2 O 2 -based bleaching agents, dental practitioners should choose for less concentrated gels, e.g., around the 15% level. Copyright © 2017 Elsevier Ltd. All rights reserved.

Coronal microleakage with five different temporary restorative materials following walking bleach technique: An ex-vivo study

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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

A novel method for preparing microfibrillated cellulose from bamboo fibers

International Nuclear Information System (INIS)

Nguyen, Huu Dat; Nguyen, Ngoc Bich; Dang, Thanh Duy; Thuy Mai, Thi Thanh; Phung Le, My Loan; Tran, Van Man; Dang, Tan Tai

2013-01-01

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 and 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. (paper)

Bleaching of cotton fabric with tetraacetylhydrazine as bleach activator for H2O2.

Science.gov (United States)

Liu, Kai; Zhang, Xuan; Yan, Kelu

2018-05-15

Tetraacetylhydrazine (TH) as bleach activator for H 2 O 2 cotton bleaching was synthesized and characterized by 1 H NMR, 13 C NMR and MS spectra. TH has better solubility than that of TAED. The CIE whiteness index (WI), H 2 O 2 decomposition rate and bursting strength were employed to investigate the performance of H 2 O 2 /TH bleaching system. By addition of TH, WI and H 2 O 2 decomposition rate increased significantly at 70 °C. Bleaching temperature, NaHCO 3 concentration and bleaching time were also discussed in detail and the loss of bursting strength is not clear. By using benzenepentacarboxylic acid (BA) as a fluorescent probe for hydroxyl radical detection, the bleaching process of H 2 O 2 /TH system was investigated. Acetylhydrazine and diacetylhydrazine were also utilized to further confirm the process. In addition, bimolecular decomposition was investigated by using 9,10-dimethylanthracene (DMA) as fluorescent probe of 1 O 2 . Based on these experimental results, the bleaching mechanism of H 2 O 2 /TH system was proposed. Copyright © 2018 Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

Pratchett, Morgan S; McCowan, Dominique; Maynard, Jeffrey A; Heron, Scott F

2013-01-01

Climate-induced coral bleaching poses a major threat to coral reef ecosystems, mostly because of the sensitivities of key habitat-forming corals to increasing temperature. However, susceptibility to bleaching varies greatly among coral genera and there are likely to be major changes in the relative abundance of different corals, even if the wholesale loss of corals does not occur for several decades. Here we document variation in bleaching susceptibility among key genera of reef-building corals in Moorea, French Polynesia, and compare bleaching incidence during mass-bleaching events documented in 1991, 1994, 2002 and 2007. This study compared the proportion of colonies that bleached for four major genera of reef-building corals (Acropora, Montipora, Pocillopora and Porites), during each of four well-documented bleaching events from 1991 to 2007. Acropora and Montipora consistently bleached in far greater proportions (up to 98%) than Pocillopora and Porites. However, there was an apparent and sustained decline in the proportion of colonies that bleached during successive bleaching events, especially for Acropora and Montipora. In 2007, only 77% of Acropora colonies bleached compared with 98% in 1991. Temporal variation in the proportion of coral colonies bleached may be attributable to differences in environmental conditions among years. Alternately, the sustained declines in bleaching incidence among highly susceptible corals may be indicative of acclimation or adaptation. Coral genera that are highly susceptible to coral bleaching, and especially Acropora and Montipora, exhibit temporal declines in their susceptibility to thermal anomalies at Moorea, French Polynesia. One possible explanation for these findings is that gradual removal of highly susceptible genotypes (through selective mortality of individuals, populations, and/or species) is producing a coral assemblage that is more resistant to sustained and ongoing ocean warming.

Changes in Bleaching Susceptibility among Corals Subject to Ocean Warming and Recurrent Bleaching in Moorea, French Polynesia

Science.gov (United States)

Pratchett, Morgan S.; McCowan, Dominique; Maynard, Jeffrey A.; Heron, Scott F.

2013-01-01

Background Climate-induced coral bleaching poses a major threat to coral reef ecosystems, mostly because of the sensitivities of key habitat-forming corals to increasing temperature. However, susceptibility to bleaching varies greatly among coral genera and there are likely to be major changes in the relative abundance of different corals, even if the wholesale loss of corals does not occur for several decades. Here we document variation in bleaching susceptibility among key genera of reef-building corals in Moorea, French Polynesia, and compare bleaching incidence during mass-bleaching events documented in 1991, 1994, 2002 and 2007. Methodology/Principal Findings This study compared the proportion of colonies that bleached for four major genera of reef-building corals (Acropora, Montipora, Pocillopora and Porites), during each of four well-documented bleaching events from 1991 to 2007. Acropora and Montipora consistently bleached in far greater proportions (up to 98%) than Pocillopora and Porites. However, there was an apparent and sustained decline in the proportion of colonies that bleached during successive bleaching events, especially for Acropora and Montipora. In 2007, only 77% of Acropora colonies bleached compared with 98% in 1991. Temporal variation in the proportion of coral colonies bleached may be attributable to differences in environmental conditions among years. Alternately, the sustained declines in bleaching incidence among highly susceptible corals may be indicative of acclimation or adaptation. Conclusions/Significance Coral genera that are highly susceptible to coral bleaching, and especially Acropora and Montipora, exhibit temporal declines in their susceptibility to thermal anomalies at Moorea, French Polynesia. One possible explanation for these findings is that gradual removal of highly susceptible genotypes (through selective mortality of individuals, populations, and/or species) is producing a coral assemblage that is more resistant to

Production of new cellulose nanomaterial from red algae marine biomass Gelidium elegans.

Science.gov (United States)

Chen, You Wei; Lee, Hwei Voon; Juan, Joon Ching; Phang, Siew-Moi

2016-10-20

Nanocellulose was successfully isolated from Gelidium elegans red algae marine biomass. The red algae fiber was treated in three stages namely alkalization, bleaching treatment and acid hydrolysis treatment. Morphological analysis was performed by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). TEM results revealed that the isolated nanocellulose had the average diameter and length of 21.8±11.1nm and of 547.3±23.7nm, respectively. Fourier transform infrared (FTIR) spectroscopy proved that the non-cellulosic polysaccharides components were progressively removed during the chemically treatment, and the final derived materials composed of cellulose parent molecular structure. X-ray diffraction (XRD) study showed that the crystallinity of yielded product had been improved after each successive treatments subjected to the treated fiber. The prepared nano-dimensional cellulose demonstrated a network-like structure with higher crystallinity (73%) than that of untreated fiber (33%), and possessed of good thermal stability which is suitable for nanocomposite material. Copyright © 2016 Elsevier Ltd. All rights reserved.

Synthesis and characterization of cellulose acetate from rice husk: eco-friendly condition.

Science.gov (United States)

Das, Archana M; Ali, Abdul A; Hazarika, Manash P

2014-11-04

Cellulose acetate was synthesized from rice husk by using a simple, efficient, cost-effective and solvent-free method. Cellulose was isolated from rice husk (RH) using standard pretreatment method with dilute alkaline and acid solutions and bleaching with 2% H2O2. Cellulose acetate (CA) was synthesized successfully with the yield of 66% in presence of acetic anhydride and iodine as a catalyst in eco-friendly solvent-free conditions. The reaction parameters were standardized at 80 °C for 300 min and the optimum results were taken for further study. The extent of acetylation was evaluated from % yield and the degree of substitution (DS), which was determined by (1)H NMR and titrimetrically. The synthesized products were characterized with the help modern analytical techniques like FT-IR, (1)H NMR, XRD, etc. and the thermal behavior was evaluated by TGA and DSC thermograms. Copyright © 2014 Elsevier Ltd. All rights reserved.

Titanium dioxide-cellulose hybrid nanocomposite and its glucose biosensor application

Energy Technology Data Exchange (ETDEWEB)

Maniruzzaman, Mohammad; Jang, Sang-Dong [Center for EAPap Actuator, Department of Mechanical Engineering, INHA University, Incheon 402-751 (Korea, Republic of); Kim, Jaehwan, E-mail: jaehwan@inha.ac.kr [Center for EAPap Actuator, Department of Mechanical Engineering, INHA University, Incheon 402-751 (Korea, Republic of)

2012-06-25

Highlights: Black-Right-Pointing-Pointer An organic-inorganic hybrid nanocomposite was fabricated by blending TiO{sub 2} nanoparticles and cellulose solution. Black-Right-Pointing-Pointer The hybrid nanocomposite has advantages of biodegradability and bio-compatibility of cellulose and physical properties of TiO{sub 2}. Black-Right-Pointing-Pointer Enzyme glucose oxidase (GOx) was immobilized into the hybrid nanocomposite and covalent bonding between TiO{sub 2} and GOx was confirmed by X-ray photoelectron analysis. Black-Right-Pointing-Pointer Linear response of the glucose biosensor was obtained in the range of 1-10 mM. - Abstract: This paper investigates the fabrication of titanium dioxide (TiO{sub 2})-cellulose hybrid nanocomposite and its possibility for a conductometric glucose biosensor. TiO{sub 2} nanoparticles were blended with cellulose solution prepared by dissolving cotton pulp with lithium chloride/N,N-dimethylacetamide solvent to fabricate TiO{sub 2}-cellulose hybrid nanocomposite. The enzyme, glucose oxidase (GOx) was immobilized into this hybrid nanocomposite by physical adsorption method. The successful immobilization of glucose oxidase into TiO{sub 2}-cellulose hybrid nanocomposite via covalent bonding between TiO{sub 2} and GOx was confirmed by X-ray photoelectron analysis. The linear response of the glucose biosensor is obtained in the range of 1-10 mM. This study demonstrates that TiO{sub 2}-cellulose hybrid nanocomposite can be a potential candidate for an inexpensive, flexible and disposable glucose biosensor.

Obtaining of Peracetic Cellulose from Oat Straw for Paper Manufacturing

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Tetyana V. Zelenchuk

2017-10-01

Full Text Available Background. Development of technology for obtaining peracetic pulp from oat straw and its use in the production of one of the paper mass types. Objective. Determination of peracetic cooking technological parameters’ optimal values for oat straw peracetic cellulose quality indicators. Methods. The oat straw cooking was carried out with peracetic acid at 95 ± 1 °C from 90 to 180 min for hydromodulus 8:1 and 7:1, using a sodium tungstate catalyst. To determine the oat straw peracetic cellulose mechanical indexes, laboratory samples of paper weighing 70 g/m2 were made. Results. Technological parameters’ optimum values (temperature, cooking duration, hydromodulus, hydrogen peroxide and acetic acid concentration for the oat straw delignification process were established. It is shown that the sodium tungstate catalyst addition to the cooking solution at a rate of up to 1 % of the plant raw material weight helps to reduce the lignin content in cellulose to 15 %. A diagram of the cellulose yield dependence on its residual lignin content for various methods of non-wood plant material species delignification is constructed. The high efficiency of the peracetic method for obtaining cellulose from non-wood plant raw materials, in particular from oat straw, has been confirmed. It is determined that the obtained peracetic cellulose from oat straw has high mechanical indexes. Conclusions. Oat straw peracetic cellulose can be used for the production of paper and cardboard mass types, in particular wrapping paper.

Treatment of pulp and paper industry bleaching effluent by electrocoagulant process

International Nuclear Information System (INIS)

Sridhar, R.; Sivakumar, V.; Prince Immanuel, V.; Prakash Maran, J.

2011-01-01

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

Bleaching Dengan Teknologi Laser

OpenAIRE

Eliwaty

2008-01-01

Penulisan tentang bleaching dengan laser dimaksudkan untuk menambah wawasan serta pengetahuan dari pembaca di bidang kedokteran gigi. Macam-macam laser yang dipergunakan dalam bleaching yaitu argon, CO2 serta dioda laser. Contoh merek produk laser yaitu Blulaze, Dentcure untuk argonlaser, Novapulse untuk C02 serta Opus 5 untuk dioda laser. Laser bleaching hasilnya dapat dicapai dalam satu kunjungan saja, cepat, efisien namun biayanya relatif mahal, dapat menimbulkan burn, sensitivitas se...

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.

Synthesis and characterization of carboxymethyl cellulose from office waste paper: A greener approach towards waste management

International Nuclear Information System (INIS)

Joshi, Gyanesh; Naithani, Sanjay; Varshney, V.K.; Bisht, Surendra S.; Rana, Vikas; Gupta, P.K.

2015-01-01

Highlights: • Carboxymethyl cellulose (CMC) was successfully prepared from waste paper. • CMC had maximum degree of substitution (DS) 1.07. • Rheological studies of CMC (DS, 1.07) showed non-Newtonian pseudoplastic behavior. • Characterization of CMC was done by FT-IR and NMR techniques. • Morphology of prepared CMC was studied by SEM. - Abstract: In the present study, functionalization of mixed office waste (MOW) paper has been carried out to synthesize carboxymethyl cellulose, a most widely used product for various applications. MOW was pulped and deinked prior to carboxymethylation. The deinked pulp yield was 80.62 ± 2.0% with 72.30 ± 1.50% deinkability factor. The deinked pulp was converted to CMC by alkalization followed by etherification using NaOH and ClCH 2 COONa respectively, in an alcoholic medium. Maximum degree of substitution (DS) (1.07) of prepared CMC was achieved at 50 °C with 0.094 M and 0.108 M concentrations of NaOH and ClCH 2 COONa respectively for 3 h reaction time. The rheological characteristics of 1–3% aqueous solution of optimized CMC product showed the non-Newtonian pseudoplastic behavior. Fourier transform infra red (FTIR), nuclear magnetic resonance (NMR) and scanning electron microscope (SEM) study were used to characterize the CMC product

Decellularized Swine Dental Pulp as a Bioscaffold for Pulp Regeneration.

Science.gov (United States)

Hu, Lei; Gao, Zhenhua; Xu, Junji; Zhu, Zhao; Fan, Zhipeng; Zhang, Chunmei; Wang, Jinsong; Wang, Songlin

2017-01-01

Endodontic regeneration shows promise in treating dental pulp diseases; however, no suitable scaffolds exist for pulp regeneration. Acellular natural extracellular matrix (ECM) is a favorable scaffold for tissue regeneration since the anatomical structure and ECM of the natural tissues or organs are well-preserved. Xenogeneic ECM is superior to autologous or allogeneic ECM in tissue engineering for its unlimited resources. This study investigated the characteristics of decellularized dental pulp ECM from swine and evaluated whether it could mediate pulp regeneration. Dental pulps were acquired from the mandible anterior teeth of swine 12 months of age and decellularized with 10% sodium dodecyl sulfate (SDS) combined with Triton X-100. Pulp regeneration was conducted by seeding human dental pulp stem cells into decellularized pulp and transplanted subcutaneously into nude mice for 8 weeks. The decellularized pulp demonstrated preserved natural shape and structure without any cellular components. Histological analysis showed excellent ECM preservation and pulp-like tissue, and newly formed mineralized tissues were regenerated after being transplanted in vivo. In conclusion, decellularized swine dental pulp maintains ECM components favoring stem cell proliferation and differentiation, thus representing a suitable scaffold for improving clinical outcomes and functions of teeth with dental pulp diseases.

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

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.

Cellulase-poor xylanases produced by Trichoderma reesei RUT C-30 on hemicellulose substrates

Energy Technology Data Exchange (ETDEWEB)

Gamerith, G.; Groicher, R. (Lenzing AG (Austria). Dept. of Research and Development); Zeilinger, S.; Herzog, P.; Kubicek, C.P. (Technische Univ., Vienna (Austria). Abt. fuer Mikrobielle Biochemie)

1992-12-01

Hemicellulose components from industrial viscose fibre production are characterized by a lower cellulose content than commerical xylan and the pressence of a carboxylic acid fraction originating from the alkaline degradation of carbohydrates during the process. This substrate, after neutralization, can be used by Trichoderma reesei RUT C-30 for the production of cellulase-poor xylanases, useful for the pulp and paper industry. The yields of xylanase ranged up to almost 400 units/ml, with a ratio of carboxymethylcellulase/xylanase of less than 0.015. This crude xylanase enzyme mixture was shown to be superior to that obtained on beech-wood xylan when used for bleaching and, particularly, upgrading of hard-wood chemical pulp by selective removal of the xylan components. Biochemical studies indicate that the low cellulase production by T. reesei grown on these waste hemicelluloses is the result of a combination of at least three factors: (a) The comparatively low content of cellulose in these hemicellulosic wastes, (b) the inhibitory action of the carboxylic acid fraction present in the hemicellulosic wastes on growth and sporulation of T. reesei, and (c) the use of a mycelial inoculum that is unable to initiate the atack on the cellulose components within the carbon source. (orig.).

Decellularized Swine Dental Pulp as a Bioscaffold for Pulp Regeneration

Directory of Open Access Journals (Sweden)

Lei Hu

2017-01-01

Full Text Available Endodontic regeneration shows promise in treating dental pulp diseases; however, no suitable scaffolds exist for pulp regeneration. Acellular natural extracellular matrix (ECM is a favorable scaffold for tissue regeneration since the anatomical structure and ECM of the natural tissues or organs are well-preserved. Xenogeneic ECM is superior to autologous or allogeneic ECM in tissue engineering for its unlimited resources. This study investigated the characteristics of decellularized dental pulp ECM from swine and evaluated whether it could mediate pulp regeneration. Dental pulps were acquired from the mandible anterior teeth of swine 12 months of age and decellularized with 10% sodium dodecyl sulfate (SDS combined with Triton X-100. Pulp regeneration was conducted by seeding human dental pulp stem cells into decellularized pulp and transplanted subcutaneously into nude mice for 8 weeks. The decellularized pulp demonstrated preserved natural shape and structure without any cellular components. Histological analysis showed excellent ECM preservation and pulp-like tissue, and newly formed mineralized tissues were regenerated after being transplanted in vivo. In conclusion, decellularized swine dental pulp maintains ECM components favoring stem cell proliferation and differentiation, thus representing a suitable scaffold for improving clinical outcomes and functions of teeth with dental pulp diseases.

Paper pulp-based adsorbents for the removal of pharmaceuticals from wastewater: A novel approach towards diversification.

Science.gov (United States)

Oliveira, Gonçalo; Calisto, Vânia; Santos, Sérgio M; Otero, Marta; Esteves, Valdemar I

2018-08-01

In this work, two pulps, bleached (BP) and raw pulp (RP), derived from the paper production process, were used as precursors of non-activated and activated carbons (ACs). In the case of non-ACs, the production involved either pyrolysis or pyrolysis followed by acid washing. For ACs production, the pulps were impregnated with K 2 CO 3 or H 3 PO 4 , and then pyrolysed and acid washed. After production, the materials were physically and chemically characterized. Then, batch adsorption tests on the removal of two pharmaceuticals (the anti-epileptic carbamazepine (CBZ) and the antibiotic sulfamethoxazole (SMX)) from ultra-pure water and from Waste Water Treatment Plant (WWTP) effluents were performed. In ultra-pure water, non-ACs were not able to adsorb CBZ or SMX while ACs showed good adsorption capacities. In WWTP effluents, although ACs satisfactorily adsorbed CBZ and SMX, they showed lower adsorption capacities for the latter. Tests with WWTP effluents revealed that the best adsorption capacities were achieved by carbons produced from BP and activated with H 3 PO 4 : 92±19mgg -1 for CBZ and 13.0±0.6mgg -1 for SMX. These results indicate the potential of paper pulps as precursors for ACs that can be applied in wastewater treatment. Copyright © 2018 Elsevier B.V. All rights reserved.

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

Science.gov (United States)

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

2016-11-20

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

Influence of Cellulosic Fibres on the Physical Properties of Fibre Cement Composites

Science.gov (United States)

Hospodarova, V.; Stevulova, N.; Vaclavik, V.; Dvorsky, T.

2017-10-01

Nowadays, there are new approaches directing to processing of non-conventional fibre-cement composites for application in the housing construction. Vegetable cellulosic fibres coming from natural resources used as reinforcement in cost-effective and environmental friendly building products are in the spotlight. The applying of natural fibres in cement based composites is narrowly linked to the ecological building sector, where a choice of materials is based on components including recyclable, renewable raw materials and low-resource manufacture techniques. In this paper, two types of cellulosic fibres coming from wood pulp and recycled waste paper with 0.2%; 0.3% and 0.5% of fibre addition into cement mixtures were used. Differences in the physical characteristics (flowability, density, coefficient of thermal conductivity and water absorbability) of 28 days hardened fibre-cement composites are investigated. Addition of cellulosic fibres to cement mixture caused worsening the workability of fresh mixture as well as absorbability of hardened composites due to hydrophilic nature of biomaterial, whereas density and thermal conductivity of manufactured cement based fibre plaster are enhanced. The physical properties of cement plasters based on cellulosic fibres depend on structural, physical characteristics of cellulosic fibres, their nature and processing.

Characterizations of biodegradable epoxy-coated cellulose nanofibrils (CNF) thin film for flexible microwave applications

Science.gov (United States)

Hongyi Mi; Chien-Hao Liu; Tzu-Husan Chang; Jung-Hun Seo; Huilong Zhang; Sang June Cho; Nader Behdad; Zhenqiang Ma; Chunhua Yao; Zhiyong Cai; Shaoqin Gong

2016-01-01

Wood pulp cellulose nanofibrils (CNF) thin film is a novel recyclable and biodegradable material. We investigated the microwave dielectric properties of the epoxy coated-CNF thin film for potential broad applications in flexible high speed electronics. The characterizations of dielectric properties were carried out in a frequency range of 1–10 GHz. The dielectric...

Humic acid adsorption onto cationic cellulose nanofibers for bioinspired removal of copper( ii ) and a positively charged dye

KAUST Repository

Sehaqui, H.

2015-01-01

© The Royal Society of Chemistry. Waste pulp residues are herein exploited for the synthesis of a sorbent for humic acid (HA), which is a major water pollutant. Cellulose pulp was etherified with a quaternary ammonium salt in water thereby introducing positive charges onto the surface of the pulp fibers, and subsequently mechanically disintegrated into high surface area cellulose nanofibers (CNF). CNF with three different charge contents were produced and their adsorption capacity towards HA was investigated with UV-spectrophotometry, quartz crystal microbalance with dissipation, and ζ-potential measurements. Substantial coverage of the CNF surface with HA in a wide pH range led to a reversal of the positive ζ-potentials of CNF suspensions. The HA adsorption capacity and the kinetics of HA uptake were found to be promoted by both acidic pH conditions and the surface charge content of CNF. It is suggested that HA adsorption onto CNF depends on electrostatic interactions between the two components, as well as on the conformation of HA. At pH ∼ 6, up to 310 mg g^-1 of HA were adsorbed by the functionalized CNF, a substantially higher capacity than that of previously reported HA sorbents in the literature. It is further shown that CNF-HA complexes could be freeze-dried into "soil-mimicking" porous foams having good capacity to capture Cu(ii) ions and positive dyes from contaminated water. Thus, the most abundant natural polymer, i.e., cellulose could effectively bind the most abundant natural organic matter for environmental remediation purpose.

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

Science.gov (United States)

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

2006-11-01

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

Morphological and spectroscopic analysis of cellulose nanocrystals extracted from oil palm empty fruit bunch fiber

Energy Technology Data Exchange (ETDEWEB)

Dasan, Y. K., E-mail: aamir.bhat@petronas.com.my; Bhat, A. H., E-mail: aamir.bhat@petronas.com.my [Department of Fundamental and Applied Sciences, Universiti Teknologi PETRONAS, 31750, Bandar Seri Iskandar, Perak (Malaysia); Faiz, A., E-mail: faizahmad@petronas.com.my [Department of Mechanical Engineering, Universiti Teknologi PETRONAS, 31750, Bandar Seri Iskandar, Perak (Malaysia)

2015-07-22

This work evaluates the use of oil palm empty fruit bunch (OPEFB) fiber as a source of cellulose to obtain nanocrystalline cellulose (CNC) by acid hydrolysis reaction. The raw OPEFB fibers were pretreated with aqueous Sodium hydroxide at 80°C followed by bleaching treatment and further hydrolyzed with Sulphuric acid at 45°C with limited range of hydrolysis time and acid concentration. The resulting CNC’s were characterized for spectroscopic, crystallographic and morphological properties using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffractometer (XRD), Transmission Electron Microscope (TEM) and Atomic Force Microscopy (AFM). Finding of this study shows that the properties of CNC’s are strongly dependent on the hydrolysis time and acid concentration.

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.

Assessment of bleaching of K-feldspar grains

International Nuclear Information System (INIS)

Zhang Jiafu; Li Shenghua; Tso, M-Y.W.

2001-01-01

Based on the difference in the bleaching rate between IRSL and TL signals, a new method of assessing the bleaching of sedimentary feldspar is proposed. All measurements for De and the bleaching factor (normalized ratio of IRSL to TL) are carried out on the same grain. K-feldspar grains from two sediments, a marine and an alluvium, from Hong Kong were tested. Their bleaching factors indicate that bleaching of the marine sediment was not uniform, whereas the latter was relatively homogeneous. Furthermore, the relatively well-bleached grains in each sample were identified

2,4,5-trihydroxy-3-methylacetophenone: A cellulosic chromophore as a case study of aromaticity

Science.gov (United States)

Nele Sophie Zwirchmayr; Thomas Elder; Markus Bacher; Andreas Hofinger-Horvath; Paul Kosma; Thomas. Rosenau

2017-01-01

The title compound (2,4,5-trihydroxy-3-methylacetophenone, 1) was isolated as chromophore from aged cellulosic pulps. The peculiar feature of the compound is its weak aromatic system that can be converted into nonaromatic (quinoid or cyclic aliphatic) tautomers, depending on the conditions and reaction partners. In alkaline media, the participation of quinoid canonic...

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.