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Academic literature on the topic 'Sulphate cellulose'

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Published: 30 May 2022
Last updated: 31 May 2022

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Journal articles on the topic "Sulphate cellulose"

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Kovensky, J., B. Sassetti, A. Fernández Cirelli, and L. Kordich. "Low Anticoagulant Activity of High Sulphated Heparan Sulphates." Thrombosis and Haemostasis 63, no. 03 (1990): 488–92. http://dx.doi.org/10.1055/s-0038-1645071.

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SummaryTwo high sulphated heparin-like polysaccharides (LI, MW 16,000 and L2, MW 11,700) were isolated from rat liver tissues, after DEAE-cellulose chromatography. Heparan sulphates from heart and lung tissues were isolated for comparison and fractionated according to their molecular weight. The anticoagulant activities in vitro were studied using clotting antifactor Xa, antifactor IIa, and APTT assay methods, falling in a narrow range (5-44 IU/mg) although the wide variability m molecular weight and sulphate content. The heparan sulphate nature of fractions L1 and L2 (sulphate/disaccharide ratio 2.05 and 2.48, respectively) has been verified by: a) low iduronic/glucuronic acid ratio; b) nitrous acid degradation followed by gel chromatography; c) heparinase treatment followed by gel chromatography; d) electrophoretic behaviour. Native proteoglycans have been isolated and the glycosidic chains compared with L1 and L2. Their anticoagulant activities in vitro and the fact that antiXa clotting activity was not neutralized by protamine sulphate are in accordance with the results of structural studies.
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Bateman, T. J., K. S. Dodgson, and G. F. White. "Primary alkylsulphatase activities of the detergent-degrading bacterium Pseudomonas C12B. Purification and properties of the P1 enzyme." Biochemical Journal 236, no. 2 (June 1, 1986): 401–8. http://dx.doi.org/10.1042/bj2360401.

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The P1 primary alkylsulphatase of Pseudomonas C12B was purified 1500-fold to homogeneity by a combination of streptomycin sulphate precipitation of nucleic acids, (NH4)2SO4 fractionation and chromatography on columns of DEAE-cellulose, Sephacryl S-300 and butyl-agarose. The protein was tetrameric with an Mr of 181000-193000, and exhibited maximum activity at pH 6.1. Primary alkyl sulphates of carbon-chain length C1-C5 or above C14 were not substrates, but the intermediate homologues were shown to be substrates, either by direct assay (C6-C9 and C12) or by gel zymography (C10, C11, C13 and C14). Increasing the chain length from C6 to C12 led to diminishing Km. Values of delta G0′ for binding substrates to enzyme were dependent linearly on chain length, indicating high dependence on hydrophobic interactions. Vmax./Km values increased with increasing chain length. Inhibition by alk-2-yl sulphates and alkane-sulphonates was competitive and showed a similar dependence on hydrophobic binding. The P1 enzyme was active towards several aryl sulphates, including o-, m- and p-chlorophenyl sulphates, 2,4-dichlorophenyl sulphate, o-, m- and p-methoxyphenyl sulphates, m- and p-hydroxyphenyl sulphates and p-nitrophenyl sulphate, but excluding bis-(p-nitrophenyl) sulphate and the O-sulphate esters of tyrosine, nitrocatechol and phenol. The arylsulphatase activity was weak compared with alkylsulphatase activity, and it was distinguishable from the de-repressible arylsulphatase activity of Pseudomonas C12B reported previously. Comparison of the P1 enzyme with the inducible P2 alkylsulphatase of this organism, and with the Crag herbicide sulphatase of Pseudomonas putida, showed that, although there are certain similarities between any two of the three enzymes, very few properties are common to all three.
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Matts, P. J., G. F. White, and W. J. Payne. "Purification and characterization of the short-chain alkylsulphatase of coryneform B1a." Biochemical Journal 304, no. 3 (December 15, 1994): 937–43. http://dx.doi.org/10.1042/bj3040937.

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Using a combination of streptomycin sulphate precipitation, and DEAE-cellulose and butyl-agarose chromatography, an alkylsulphatase active towards short-chain alkyl sulphates has been purified approx. 70-fold from extracts of coryneform B1a grown on butyl-1-sulphate. The enzyme protein is dimeric with a subunit molecular mass of 77.6 kDa, has an isoelectric point of pI 7.2, and converts butyl-1-sulphate stoichiometrically into butan-1-ol and inorganic sulphate. Stoichiometric incorporation of 18O from H2(18)O into sulphate during the reaction showed that enzymic hydrolysis occurred at the O-S bond of the C-O-S ester linkage. The enzyme was active on C3-C7 linear primary alkyl sulphates but not on higher (C8,9) or lower (C1,2) homologues, although the latter pair were competitive inhibitors. The specificity constant (kcat./Km) was highest for pentyl sulphate (Km 1.89 +/- 0.38 mM; kcat. 6.86 +/- 0.52 s-1) and decreased for higher and lower homologues. No activity was detected towards C3-C9 racemic alkyl-2-sulphates, D- or L-enantiomers of butyl-2-sulphate, the symmetrical secondary alkyl sulphates pentyl-3-sulphate, heptyl-4-sulphate, nonyl-5-sulphate, C1-C8 alkane sulphonates, choline sulphate, or butyric acid-4-sulphate; none of these compounds (except the symmetrical esters and butyric acid-4-sulphate, which were not tested) was demonstrably inhibitory. The enzyme was compared with other alkylsulphatases in terms of substrate specificity and mode of action.
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Horwood, Jennifer. "Cellulose sulphate microbicide trial halted." Lancet Infectious Diseases 7, no. 3 (March 2007): 183. http://dx.doi.org/10.1016/s1473-3099(07)70039-7.

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Dachavaram, Soma Shekar, Narsimha R. Penthala, Julie L. Calahan, Eric J. Munson, and Peter A. Crooks. "Highly sulphated cellulose: a versatile, reusable and selective desilylating agent for deprotection of alcoholic TBDMS ethers." Organic & Biomolecular Chemistry 16, no. 33 (2018): 6057–62. http://dx.doi.org/10.1039/c8ob01438h.

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A mild, effcient protocol was developed for the deprotection of alcoholic TBDMS ethers using highly sulphated HS-cellulose sulphate catalyst, which selectively cleaves alcoholic TBDMS ethers in bis-TBDMS ethers containing both alcoholic and phenolic TBDMS ether moieties.
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Gil-Castell, Oscar, Pablo Reyes-Contreras, Pabla Andrea Barra, Regis Teixeira Mendonça, Isabel Carrillo-Varela, José David Badia, Angels Serra, and Amparo Ribes-Greus. "The Role of Eucalyptus Species on the Structural and Thermal Performance of Cellulose Nanocrystals (CNCs) Isolated by Acid Hydrolysis." Polymers 14, no. 3 (January 21, 2022): 423. http://dx.doi.org/10.3390/polym14030423.

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Cellulose nanocrystals (CNCs) are attractive materials due to their renewable nature, high surface-to-volume ratio, crystallinity, biodegradability, anisotropic performance, or available hydroxyl groups. However, their source and obtaining pathway determine their subsequent performance. This work evaluates cellulose nanocrystals (CNCs) obtained from four different eucalyptus species by acid hydrolysis, i.e., E. benthamii, E. globulus, E. smithii, and the hybrid En × Eg. During preparation, CNCs incorporated sulphate groups to their structures, which highlighted dissimilar reactivities, as given by the calculated sulphate index (0.21, 0.97, 0.73 and 0.85, respectively). Although the impact of the incorporation of sulphate groups on the crystalline structure was committed, changes in the hydrophilicity and water retention ability or thermal stability were observed. These effects were also corroborated by the apparent activation energy during thermal decomposition obtained through kinetic analysis. Low-sulphated CNCs (E. benthamii) involved hints of a more crystalline structure along with less water retention ability, higher thermal stability, and greater average apparent activation energy (233 kJ·mol−1) during decomposition. Conversely, the high-sulphated species (E. globulus) involved higher reactivity during preparation that endorsed a little greater water retention ability and lower thermal stability, with subsequently less average apparent activation energy (185 kJ·mol−1). The E. smithii (212 kJ·mol−1) and En × Eg (196 kJ·mol−1) showed an intermediate behavior according to their sulphate index.
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Fedoskin, I. A., E. D. Sofronova, and V. A. Lipin. "BLEACHING OF SULPHATE CELLULOSE FROM HARDWOOD." Вестник Санкт-Петербургского государственного университета технологии и дизайна. Серия 4: Промышленные технологии, no. 3 (2020): 90–94. http://dx.doi.org/10.46418/2619-0729_2020_3_8.

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Lidholt, K., L. Kjellén, and U. Lindahl. "Biosynthesis of heparin. Relationship between the polymerization and sulphation processes." Biochemical Journal 261, no. 3 (August 1, 1989): 999–1007. http://dx.doi.org/10.1042/bj2610999.

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Incubation of a mouse mastocytoma microsomal fraction with UDP-[3H]GlcA and UDP-GlcNAc yielded proteoglycans containing non-sulphated polysaccharide chains. Similar incubations performed in the presence of sulphate donor 3′-phosphoadenosine 5′-phosphosulphate (PAPS) produced both sulphated and non-sulphated proteoglycans, which were separated by chromatography on DEAE-cellulose Analysis by gel chromatography of single polysaccharide chains, released from the proteoglycans by alkali treatment, showed that the non-sulphated chains produced during incubation for 5 min or 25 min, either in the absence or in the presence of PAPS, were of fairly small molecular size, with an average peak Mr of approx. 10 x 10(3)-15 x 10(3). In contrast, the sulphated chains exceeded Mr 100 x 10(3) Pulse-chase experiments suggested that sulphated chains were capable of further elongation. These results indicate that sulphation promotes, by so far unknown mechanisms, further chain elongation. Sulphated proteoglycan (retarded on DEAE-cellulose chromatography) isolated after similar incubation of the microsomal fraction for 1 min only was found to contain a mixture of sulphated and virtually non-sulphated polysaccharide chains. However, when [35S]PAPS was included in the incubations, some 35S was found to be associated, essentially as N-sulphate groups, also with the latter type of chains, preferentially the high-Mr fraction. These results are interpreted in terms of a biosynthetic model by which the heparin proteoglycan is generated through transient interactions of macromolecular intermediates with distinctly separate complexes of membranebound enzymes.
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Antušková, V., and I. Kučerová. "The impact of inorganic compounds used for protection of wood on cellulose." Koroze a ochrana materialu 58, no. 2 (June 1, 2014): 36–42. http://dx.doi.org/10.2478/kom-2014-0008.

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Abstract Inorganic compounds were often used to protect wood from wood-decaying fungi and insects (e.g. compounds of arsenic, copper, chromium, zinc or boron) or as a retarder of combustion (e.g. ammonium salts, boron compounds). However, their use may accelerate degradation processes, which may show up as worsening of mechanical properties. The study deals with the impact of selected inorganic compounds (sodium chloride, copper sulphate pentahydrate, boric acid and ammonium sulphate) on cellulose. The samples of cellulose impregnated with the said compounds were subject to artificial aging. The cellulose was monitored for weight changes, changes in colour, values of aqueous extract pH, an average polymerization grade, mechanical properties, elementary composition and the content of bound inorganic compounds. The study was meant to identify stability of the used inorganic compounds in the conditions of artificial aging. The results imply that copper sulphate pentahydrate and ammonium sulphate accelerated degradation of cellulose the most. The effect of boric acid lead to larger deterioration of specimens namely in the conditions of dry aging. Sodium chloride had a negligible impact on the course of degradation. Used compounds continue to be at least partly retained in the cellulose specimens even after rinsing.
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Karim, Latiffah, and Shikh Mohd Shahrul Nizan Shikh Zahari. "Stability of cellulases in ionic liquids." Malaysian Journal of Fundamental and Applied Sciences 15, no. 3 (June 25, 2019): 432–35. http://dx.doi.org/10.11113/mjfas.v15n3.1297.

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Lignocellulosic biomass has been used as an alternative source to food crops that serve as feedstock for bioenergy production. The conversion of biomass to bioenergy required pretreatment process. Ionic liquids (ILs) have been recognized as promising solvents that are capable of solubilizing and separating components of lignocellulosic biomass. This research focuses on understanding how ILs affects the activity of cellulases in the enzymatic saccharification process. Sigmacell cellulose was used in the enzymatic saccharification process inste. Two different ILs were added in the enzymatic saccharification mixtures and the activity of a mixture of commercially available cellulases was measured using high-performance liquid chromatography (HPLC) to measure glucose release. Sulphate based ILs were more harmful for cellulase action than [EMIM][OAc]. [HBIM][HSO4] inactivated commercial cellulases (Celluclast®) and cellobiase (Novozyme188) in the enzymatic saccharification process. In this research, it was observed that the main factor that affects the activity of cellulase is pH.
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Dissertations / Theses on the topic "Sulphate cellulose"

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Риляков, Ілля Леонідович. "Підвищення ефективності технології виробництва сигаретного паперу." Master's thesis, КПІ ім. Ігоря Сікорського, 2020. https://ela.kpi.ua/handle/123456789/38492.

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Актуальність теми. Розширення сировинної бази целюлозно-паперової галузі України за рахунок використання целюлози з відходів сільського господарства. Виробництво сигаретного паперу та забезпечення стабільності його якості шляхом використання новітніх досягнень в паперовому виробництві та сучасних технологій одержання целюлози. Мета і задачі дослідження. Метою дисертаційної роботи є вивчення особливостей сигаретного паперу та вдосконалення технології його виробництва для підвищення якості продукції. Для досягнення вказаної мети було поставлено наступні задачі: - ознайомлення з властивостями сигаретного паперу; - одержати солом'яну целюлозу окисно-органосольвентним способом делігніфікації та дослідити її паперотворні властивості; - вдосконалити технологічний процес виробництва сигаретного паперу; - вибрати і розрахувати основне технологічне обладнання. - провести аналіз потенціалу даної роботи до використання у стартапі. Об’єкт дослідження: процеси одержання соломяної целюлози та виготовлення сигаретного паперу. Предмет дослідження: технологічні параметри процесу делігніфікації січки пшеничної соломи, параметри процесів формування, пресування, проклеювання і сушіння паперового полотна. Методи дослідження: для визначення впливу технологічних параметрів одержання целюлози використовували хімічні, фізико-хімічні та фізико-механічні методи аналізу. Обгрунтування іноваційних рішень в технологічному потоці базувалося на теоретичних методах аналізу. Практичне значення одержаних результатів: запропонований технологічний потік з виробництва виробництва сигаретного паперу з використанням соломяної целюлози дозволить покращити якість готової продукції та зменшити її собівартість. Апробація результатів дисертації: Основні положення дисертаційної роботи доповідалися та обговорювалися на міжнародній закордонній конференції IV international scien-tific and practical conference The world of scitnce and innovation, London, United Kingdom, 11-13 november, 2020 р.
Theme actuality. Expansion of the raw material base of the pulp and paper industry of Ukraine due to the use of pulp from agricultural waste. Production of cigarette paper and ensuring the stability of its quality through the use of the latest advances in paper production and modern technologies for pulp production. The purpose and objectives of the study. The purpose of the dissertation is to study the features of cigarette paper and improve the technology of its production to improve product quality. To achieve the goal, you need to solve the following tasks: - acquaintance with the properties of cigarette paper; - to obtain straw cellulose by oxidative-organosolvent method of delignification and to investigate its paper-forming properties; - to improve the technological process of cigarette paper production; - select and calculate the main technological equipment. - to analyze the potential of this work for use in startups. Object of study: the process of making document paper. Subject of study: processes of production of straw cellulose and production of cigarette paper. Methods of study: technological parameters of the process of delignification of wheat straw chips, parameters of the processes of forming, pressing, gluing and drying of paper web. The practical value of the obtained results: the proposed technological stream for the production of cigarette paper with the use of straw pulp will improve the quality of finished products and reduce its cost. Approval of the thesis results: The main provisions of the dissertation were reported and discussed at the international international conference IV international scien-tific and practical conference. The world of science and innovation, London, United Kingdom, 11-13 November, 2020.
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Silva, Marileide Gomes da. "Produtividade, idade e qualidade de madeira de Eucalyptus destinada à produção de polpa celulósica branqueada." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-17032011-162129/.

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Este trabalho teve como objetivo verificar a influência da produtividade e da idade sobre a qualidade da madeira proveniente de clone híbrido de Eucalyptus grandis x Eucalyptus urophylla para produção de polpa celulósica braqueada. Utilizou-se madeira de um único clone proveniente de áreas com elevada produtividade, média de 33 m3 ha-1 ano-1, onde os solos eram argilosos e de áreas com baixa produtividade, média de 17 m3 ha-1 ano-1, sendo estes solos arenosos. Nos dois tipos de solos foram avaliadas árvores com idades de 4, 5, 6 e 7 anos, proveniente de povoamentos florestais do estado do Pará - Brasil. Para cada amostra foram utilizadas 10 árvores com diâmetros médio do povoamento. Os materiais foram avaliados com relação a densidade básica, composição química e desempenho frente ao processo kraft de polpação. Os cozimentos foram realizados a 166°C com 60 min de aquecimento, 85 min de cozimento e carga de álcali variável de acordo com a necessidade de cada material para obtenção de kappa 18±0,5. Os resultados obtidos mostraram que a densidade básica da madeira aumentou em função da idade, variando de 0,510 a 604 g cm-3 com 4 e 7 anos, respectivamente;essa maior densidade em idades mais elevadas é explicada pela maior proporção de madeira adulta, em relação a madeira juvenil. A quantidade de extrativos totais também aumentou em função da idade variando de 4,9 a 5,7% com 4 e 7 anos, respectivamente. A quantidade de lignina não apresentou diferença significativa e variou entre 29,26 e 29,72%. As amostras provenientes de solos argilosos apresentaram maior rendimento depurado (50 a 52%), e requereram menor carga de álcali (21 a 24,5% de álcali ativo) para o mesmo nível de deslignificação (kappa 18±0,5); para as amostras de solos arenosos a carga de álcali foi de 21,5 a 25% e rendimento de 48 a 51%. As polpas celulósicas oriundas de materias de solos argilosos apresentaram menor quantidade de ácidos hexenurônicos e maior viscosidade, além de apresentarem melhores propriedades físico-mecânicas, como volume específico, resistência ao ar, índices de tração, rasgo e estouro. As madeiras provenientes de área com elevada produtividade apresentaram melhor qualidade para produção de polpa celulósica em relação a área de baixa produtividade.
This study aimed to determine the influence of productivity and age on wood quality from hybrid clones of Eucalyptus grandis x Eucalyptus urophylla for bleached pulp production. The material considered were collected in areas with high productivity, an average of 33 m3 ha-1 year-1, clay soils and low-productive areas, an average of 17 m3 ha-1 year-1, sandy soils. In both types of soils, we evaluated trees aged 4, 5, 6 and 7 years, from forest stands from the state of Pará Brazil. For each sample were used 10 average trees (diameter). Materials were evaluated for chemical composition, basic density and performance in relation to the kraft pulping process. The cooking was performed at 166°C with 60 min heating, 85 min cooking and alkali charge varying according to the needs of each material to obtain kappa number of 18±0.5. Results showed that the basic density of wood increases with age, ranging from 0.510 to 604 g cm-3 with 4 and 7 years, respectively. This increased density in older ages is possibly explained by the higher proportion of mature wood, in relation to juvenile wood. The total amount of extractives also increased with age varying from 4.9 to 5.7% with 4 and 7 years, respectively. The amount of lignin was not significantly different ranging from 29.26 to 29.72%. Samples from clay soils had a higher yield of pulp (50 to 52%), and required lower alkali charge (21 to 24.5% active alkali) to the same level of delignification (kappa number 18±0.5); for samples from sandy soil alkali charge was 21.5 to 25% and yield of 48 to 51%. Pulp from material derived from clay soils had less hexenuronic acid and higher viscosity, which is justified by the lower alkali applied. In addition, also presented better physical and mechanical propert ies such as specific volume, air resistance, tensile, tear and burst index. Wood from an area of high productivity showed better quality for pulp production over an area of low productivity, for consuming a smaller amount of chemical charge to the same kappa number, higher pulp yield, pulp with higher viscosity and better physical and mechanical properties.
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Mayende, Lungisa. "Isolation of a Clostridium Beijerinckii sLM01 cellulosome and the effect of sulphide on anaerobic digestion." Thesis, Rhodes University, 2007. http://hdl.handle.net/10962/d1004032.

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Cellulose is the most abundant and the most resistant and stable natural organic compound on earth. Enzyme hydrolysis is difficult because of its insolubility and heterogeneity. Some (anaerobic) microorganisms have overcome this by having a multienzyme system called the cellulosome. The aims of the study were to isolate a mesophilic Clostridium sp. from a biosulphidogenic bioreactor, to purify the cellulosome from this culture, to determine the cellulase and endoglucanase activities using Avicel and carboxymethylcellulose (CMC) as substrates and the dinitrosalicyclic (DNS) method. The organism was identified using 16S rDNA sequence analysis. The sequence obtained indicated that a strain of Clostridium beijerinckii was isolated. The cellulosome was purified from the putative C. beijerinckii sLM01 host culture using affinity chromatography purification and affinity digestion purification procedures. The cellulosomal and non-cellulosomal fractions of C. beijerinckii sLM01 were separated successfully, but the majority of the endoglucanase activity was lost during the Sepharose 4B chromatography step. These cellulosomal and non-cellulosomal fractions were characterised with regards to their pH and temperature optima and effector sensitivity. Increased additions of sulphide activated the cellulase activity of the cellulosomal and non-cellulosomal fractions up to 700 %, while increased additions of sulphate either increased the activity slightly or inhibited it dramatically, depending on the cellulosomal and non-cellulosomal fractions. Increased additions of cellobiose, glucose and acetate inhibited the cellulase and endoglucanase activities. pH optima of 5.0 and 7.5 were observed for cellulases and 5.0 for endoglucanases of the cellulosomal fraction. The noncellulosomal fraction exhibited a pH optimum of 7.5 for both cellulase and endoglucanase activities. Both fractions and enzymes exhibited a temperature optimum of 30 °C. The fundamental knowledge gained from the characterisation was applied to anaerobic digestion, where the effect of sulphide on the rate-limiting step was determined. Sulphide activated cellulase and endoglucanase activities and increased the % chemical oxygen demand (COD) removal rate. Levels of volatile fatty acids (VFAs) were higher in the bioreactor containing sulphide, substrate and C. beijerinckii. Sulphide therefore accelerated the rate-limiting step of anaerobic digestion.
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Walter, Karin. "Influence of acid hydrogen peroxide treatment on refining energy and TMP properties." Licentiate thesis, Mid Sweden University, Department of Natural Sciences, Engineering and Mathematics, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-9207.

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The potential of using acid hydrogen peroxide under Fenton conditions to lower the electrical energy consumed during the production of Black spruce (Picea mariana) thermomechanical pulp (TMP) was investigated. The chemical system, which consisted of ferrous sulphate, hydrogen peroxide and optionally an enhancer (3,4-dimethoxybenzyl alcohol, ethylenediaminetetraacetic acid or oxalic acid/sodium oxalate), was evaluated as an inter-stage treatment where the primary refiner was used as a mixer. The produced TMPs were thoroughly characterised in order to explain the effect of the chemical system on fibre development and to be able to propose a mechanism for the impact on refining energy reduction. The possibility to improve the optical properties by washing, chelating and sodium dithionite or hydrogen peroxide bleaching the treated pulps was evaluated.

 

The results obtained in a pilot plant trial show that it is possible to significantly reduce the comparative specific energy consumption by approximately 20% and 35% at a freeness value of 100 ml CSF or a tensile index of 45 Nm/g by using 1% and 2% hydrogen peroxide respectively. The energy reduction is obtained without any substantial change in the fractional composition of the pulp, though tear strength is slightly reduced, as are brightness and pulp yield. No major differences between the reference pulp and the chemically treated pulps were found with respect to fibre length, width or cross-sectional dimensions. However, the acid hydrogen peroxide-treated pulps tend to have more collapsed fibres, higher flexibility, a larger specific surface area and a lower coarseness value. The yield loss accompanying the treatment is mainly a consequence of degraded hemicelluloses. It was also found that the total charge of the chemically treated pulps is higher compared to the reference pulps, something that may have influenced the softening behaviour of the fibre wall.

 

A washing or chelating procedure can reduce the metal ion content of the chemically treated TMPs considerably. The amount of iron can be further reduced to a level similar to that of untreated pulps by performing a reducing agent-assisted chelating stage (QY) with dithionite. The discoloration cannot, however, be completely eliminated. The brightness decrease of the treated pulps is thus not only caused by higher iron content in the pulp, but is also dependent on the type of iron compound and/or other coloured compounds connected with the acid hydrogen peroxide treatment. Oxidative bleaching with hydrogen peroxide (P) is more effective than reductive bleaching with sodium dithionite in regaining the brightness lost during the energy reductive treatment. Using a QY P sequence, a hydrogen peroxide charge of 3.8% was needed to reach an ISO brightness of 75% for the chemically treated pulps. The corresponding hydrogen peroxide charge for the untreated TMP reference was 2.5%.

 

The radicals generated in the Fenton reaction will probably attack and weaken/soften the available outer fibre wall layers. This could facilitate fibre development and consequently lower the electrical energy demand for a certain degree of refinement.

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Kilian, André. "Control of an acid sulphite batch pulp digester based on a fundamental process model." Pretoria : [s.n.], 1999. http://upetd.up.ac.za/thesis/available/etd-12202006-100726/.

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Hinojosa, Eduardo Alberto Lazo. "Remoção de matéria orgânica e cor de efluente kraft por adsorção usando carvão ativado e argila." Universidade Tecnológica Federal do Paraná, 2014. http://repositorio.utfpr.edu.br/jspui/handle/1/1302.

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CAPES
Atualmente há preocupação da sociedade em relação aos impactos gerados pelas indústrias ao meio ambiente. Para produção de celulose e de papel é usada grande quantidade de água, madeira e produtos químicos, sendo gerado efluente nos diferentes processos produtivos da indústria. A matéria orgânica e a cor do efluente do processo Kraft se devem à presença de moléculas derivadas da lignina que são difíceis de serem removidas ou biodegradadas. Com vistas à remedição deste efluente, o presente trabalho busca avaliar a remoção de cor e matéria orgânica residual de efluente de celulose Kraft pré-tratado biologicamente, usando carvão ativado de casca de coco e argila montmorilonita pelo método de adsorção através de delineamentos experimentais. Para remoção de cor e matéria orgânica foram avaliados os fatores: a) pH do efluente; b) massa do material adsorvente no processo de adsorção e c) temperatura. A capacidade de adsorção de matéria orgânica e cor no carvão ativado e argila montmorilonita foram determinados pelo modelo matemático de Langmuir e Freundlich, por meio de ensaios de construção de isotermas de adsorção em efluente Kraft. O efluente foi caracterizado quanto a DQO, DBO5,20, COT e cor verdadeira antes e depois do tratamento terciário. Para o tratamento do efluente foram empregadas duas temperaturas: 25 e 40°C, seguiu-se planejamento fatorial completo 32 em triplicata com ponto central tendo como variáveis pH (5,0; 6,0 e 7,0) e massa de material adsorvente (0,5; 1,0 e 1,5 g). O planejamento experimental utilizado permitiu obter os melhores resultados com carvão ativado em 40 °C, pH 7,0 e 1,5 g de adsorvente com remoção de: 98% de COT, 83% de DQO, 97% de DBO5,20 e 95% de cor verdadeira e para argila em temperatura de 40 oC, pH 7, e 1,5 g de adsorvente com remoção de: 55% de COT, 50% de DQO, 90% de DBO5,20, e 56% de cor verdadeira. A principal variável responsável pela remoção de cor e matéria orgânica foi a massa de adsorvente seguida do pH. Também foi avaliada a possibilidade de aproveitamento do resíduo obtido a partir do processo de adsorção na incorporação de cinzas de carvão na produção de argamassas com teores de 0,4%, 1,0% e 1,2%; em cimento portland, areia e água com tempos de cura de 7 e 28 dias fazendo testes de resistência à compressão. Para a reutilização da argila foram utilizados 15% de argila do processo de adsorção, 25% de vidro e 60% de argila vermelha, para a confecção de corpos de prova cerâmico à temperatura de 1100 oC a 1150 oC. De modo geral, o processo de tratamento proposto neste trabalho utilizando carvão ativado, demostrou ser boa alternativa comparado com argila montmorilonita para redução de cor e matéria orgânica residual do efluente de processo Kraft, tendo-se em vista a utilização da cinza do carvão utilizado no processo de adsorção como um agregado para formação de argamassas na construção civil e argila utilizada na adsorção como material cerâmico.
Nowadays, there is a concern of society regarding the impacts caused by the industries on the environment. Large amounts of water, wood and chemichal are used to produce cellulose and paper, and contaminated effluents are generated through the various industrial processes associated. The organic matter and the color of the Kraft effluent are due to the presence of lignin-derived molecules that are difficult to be removed or biodegraded. With intent to remediate this effluent, this study aim to evaluate the removal of color and residual organic matter from biologically pretreated Kraft effluent, using activated carbon from coconut shell and montmorillonite clay by adsorption method through experimental designs. For the color and organic matter removal, the following factors were evaluated: a) pH of the effluent; b) the mass of the adsorbent material in the adsorption process and c) temperature. The adsorption capacity of organic matter and color in the activated carbon and in the montmorillonite clay were determined by the mathematical model of Langmuir and Freundlich, by means of isotherm adsorption construction in Kraft effluent.The effluent was characterized by COD, DBO5,20, COT and true color before and after the tertiary treatment. For it treatment two temperatures were employed: 25 °C and 40 °C, followed by a 32 full factorial design with center point in triplicate, using pH (5.0, 6.0 and 7.0) and masses of adsorbent material (0.5, 1.0 and 1.5 g) as variables. The experimental design used showed that the best results with activated carbon are obtained at 40 ° C, pH 7.0 and 1.5 g of adsorbent with removals of 98% of TOC, 83% of COD, 97% of BOD5,25 and 95% of true color. With clay, the best results occurred at temperature of 40 ° C, pH 7, and 1.5 g of adsorbent to remove 55% of COT, 50% of COD, 90% of BOD5,20 and 56% of true color. The main responsible for the removal of color and organic matter was the mass of adsorbent, followed by the pH. It was also evaluated the possibility of using the residue obtained from the adsorption process in the incorporation of carbon ash to produce mortars with levels of 0.4%, 1.0% and 1.2% in Portland cement, sand and water, with curing times of 7 and 28 days, for which compressive strength tests were performed. To reuse the clay, 15% of the clay from the adsorption process was used, together with 25% of glass and 60% of red clay, in order to construct ceramics bodies specimen generated at temperatures from 1100 °C to 1150 °C. The treatment process proposed in this work using activated carbon demonstrated to be, in general, a good alternative compared to montmorillonite clay for the color reduction and residual organic matter removal from Kraft process effluent, while residues from both process can be used as aggregates for mortars and ceramic body production.
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Gustavsson, Catrin. "On the Interrelation Between Kraft Cooking Conditions and Pulp Composition." Doctoral thesis, Stockholm, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4232.

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Åkerholm, Margaretha. "Ultrastructural Aspects of Pulp Fibers as Studied by Dynamic FT-IR Spectroscopy." Doctoral thesis, KTH, Fibre and Polymer Technology, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3609.

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Dynamic (or 2D) FT-IR spectroscopy in combination withpolarized IR irradiation has been used in this work to studywood polymer orientation and interactions on theultrastructural level in wood fibers in the native state aswell as the effects of different pulping processes. The woodpolymer interactions were studied under both dry and humidconditions.

The matrix of lignin and hemicelluloses located between thewell-ordered cellulose fibrils in the wood cell wall of sprucewas here shown to be more highly ordered than has earlier beenrevealed. It was confirmed that glucomannan is orientedparallel to the cellulose fibrils and is highly coupled to it.The lignin was also shown to have a main orientation in thestructure although this is probably not as strong as that ofglucomannan. The orientation of the lignin may derive from thefact that the polysaccharides act as templates during thelignification of the cell wall. This organization implies thatnot only the cellulose but also the lignin and thehemicelluloses have different mechanical properties in thelongitudinal and cross-fiber directions.

The ability to gain molecular information on the stresstransfer in polymers with dynamic FT-IR spectroscopy made itpossible to verify experimentally earlier molecularcalculations on the stress transfer within the cellulose chain.It was also possible to show, on the molecular level, thedominant importance of the cellulose fibrils for the stresstransfer in the longitudinal direction of pulp fibers,including lignin-rich mechanical pulp fibers. The glucomannanof softwood fibers was also shown to participate in the stresstransfer in the fiber direction indicating a close associationwith the cellulose, whereas the xylan showed no dynamicresponse. Already under dry conditions, the lignin was shown tohave a more viscoelastic response than the polysaccharidesduring the loading of pulp fibers and it was thus able to moveindependently of the cellulose.

The enhanced spectral resolution obtained with dynamic FT-IRspectroscopy made it possible to study the crystalstructure/chain order of cellulose in pulp fibers. Thepossibility of following changes in the relative cellulose Iallomorph composition of pulp fibers was demonstrated for somechemical pulps.

Dynamic FT-IR experiments under humid conditions and ofelevated temperatures made it possible to study the softeningof the biopolymers in their native environment. This was alsodemonstrated for some different pulps, and this may be apromising tool for obtaining viscoelastic information on themolecular level in composite systems such as wood fibers.

Keywords:cellulose, cooperation, crystallinity, dynamictest, glucomannan, hardwood, holocellulose, humidity, infraredspectroscopy, kraft pulp, lignin, mechanical pulp, orientation,polarised light, softwood, strain, sulphite pulp,viscoelasticity, xylan

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Ferreira, Hugo Miguel Lambuça. "Overcome challenges in influenza virus-like particles downstream process." Master's thesis, 2017. http://hdl.handle.net/10362/24817.

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The development of new vaccines for influenza virus introduced a new generation of vaccines using virus-like particles (VLPs). The lack of genetic material, possibility of production on cell lines and presence of antigens with immunogenicity are the main advantages over the traditional vaccines. The development of a cost-effective downstream process while maintaining the high purity, potency and quality of VLPs is a challenge. In this thesis, several purification steps – clarification, concentration, chromatography, polishing and sterile filtration – were studied to develop a new downstream proves for influenza VLPs. In clarification step, a strategy using D0HC followed by Opticap XL SHC filters presented the best result. For concentration step, the cassette with cut-off of 300 kDa presented a higher yield on hemagglutinin recovery and the lowest process time. For chromatography step, the membrane Sartobind Q and the resin HiTrap Q HP were evaluated, concluding that resin HiTrap presented higher dynamic binding capacity and better resolution on elution. For polishing step, size-exclusion chromatography and multimodal chromatography operate in flow-through mode were compared. The last presented higher recovery yield on hemagglutinin and it was select due to the non-limitation for scale-up. Different materials were analysed for the final sterile filtration. A proof of concept run was performed were the optimized conditions and best devices were evaluated. In the end of process, it was obtained influenza VLPs with concentration and quality enough to advance for animal in vivo studies and for clinical phase I. Additionally, a new tool – magnetic sulphated cellulose particles – was evaluated with the goal to obtain purified and concentrated samples to use in characterization techniques. Overall, this thesis contributes to introduce a new tool and a novel cost-effective downstream purification process with high purity, potency and quality for the next generation of influenza vaccines - VLPs.
O desenvolvimento de novas vacinas para o vírus de influenza introduziu uma nova geração de vacinas utilizando partículas semelhantes a vírus (VLPs). A ausência de material genético, possibilidade de produção em linhas celulares e presença de antigénios com imunogenicidade são as principais vantagens em relação às vacinas tradicionais. O desenvolvimento de um processo de purificação de baixo custo mantendo a elevada pureza, potencia e qualidade das VLPs é um desafio. Nesta tese, alguns passos de purificação – clarificação, concentração, cromatografia, polimento e filtração estéril final – foram estudados para desenvolver um novo processo de purificação de VLPs de influenza. Na clarificação, a estratégia usando os filtros D0HC seguido do Opticap XL SHC apresentaram os melhores resultados. Na concentração, a cassete com cut-off de 300 kDa apresentou um maior rendimento na recuperação de hemaglutinina e o mais baixo tempo de operação. Na cromatografia, a membrana Sartobind Q e a resina HiTrap Q HP foram avaliadas, concluindo-se que a resina apresenta maior capacidade de ligação dinâmica e maior resolução na eluição. No polimento, a cromatografia de exclusão molecular e a cromatografia multimodal, operada em flow-through comparadas. Esta última apresentou valores superiores de recuperação de hemaglutinina sendo escolhida por não conter limitações no escalamento. Diferentes materiais foram analisados na filtração estéril final. Na realização da corrida de prova de conceito as condições ótimas e os melhores materiais foram estudadas. No final do processo, obteve-se VLPs de influenza na concentração e qualidade suficiente para avançar para estudos em animais in vivo e para fase clínica I. Adicionalmente, uma nova ferramenta – partículas magnéticas de celulose sulfatada – foram estudadas com objetivo de obter VLPs purificadas e concentradas para utilização em técnicas de caracterização. Em geral, esta tese contribuiu para introduzir uma nova ferramenta e um novo processo de purificação mais económico com elevada pureza, potência e qualidade, para a nova geração de vacinas - VLPs.
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Book chapters on the topic "Sulphate cellulose"

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Dautzenberg, H., B. Lukanoff, and K. Neubauer. "Sodium cellulose sulphate as a component for polyelectrolyte complex formation—preparation, characterisation, testing." In Cellulose and Cellulose Derivatives, 435–44. Elsevier, 1995. http://dx.doi.org/10.1533/9781845698539.5.435.

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"The Diversity of Uses for Cellulose Sulphate Encapsulation." In Bioencapsulation of Living Cells for Diverse Medical Applications, edited by John A. Dangerfield, Brian Salmons, Randolph Corteling, Jean-Pierre Abastado, John Sinden, Walter H. Gunzburg, and Eva M. Brandtner, 70–92. BENTHAM SCIENCE PUBLISHERS, 2013. http://dx.doi.org/10.2174/9781608057207113010006.

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Bamitale Osho, Michael, and Sarafadeen Olateju Kareem. "Prospects of Biocatalyst Purification Enroute Fermentation Processes." In Fermentation - Processes, Benefits and Risks [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.97382.

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Biotransformation of broth through fermentation process suffers a major setback when it comes to disintegration of organic substrates by microbial agents for industrial applications. These biocatalysts are in crude/dilute form hence needs to be purified to remove colloidal particles and enzymatic impurities thus enhancing maximum activity. Several contractual procedures of concentrating dilute enzymes and proteins had been reported. Such inorganic materials include ammonium sulphate precipitation; salting, synthetic polyacrylic acid; carboxy-methyl cellulose, tannic acid, edible gum and some organic solvents as precipitants etc. The emergence of organic absorbents such as sodom apple (Calostropis procera) extract, activated charcoal and imarsil had resulted in making significant impact in industrial circle. Various concentrations of these organic extracts have been used as purifying agents on different types of enzyme vis: lipase, amylase, protease, cellulase etc. Purification fold and stability of the enzyme crude form attained unprecedented results.
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Nousiainen, Pertti, and Marianna Vehviläinen. "CELSOL - MODIFICATION OF PINE SULPHATE PAPER GRADE PULP WITH TRICHODERMA REESEI CELLULASES FOR FIBRE SPINNING." In Recent Advances in Environmentally Compatible Polymers, 371–78. Elsevier, 2001. http://dx.doi.org/10.1533/9781845693749.6.371.

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Conference papers on the topic "Sulphate cellulose"

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Romanova, Lidia, and Ilona V. Iakimova. "New approach to environmental engineering for sulphate cellulose production." In International Heat Transfer Conference 12. Connecticut: Begellhouse, 2002. http://dx.doi.org/10.1615/ihtc12.3560.

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Suckling, Paul, Nicola Calder, Paul Humphreys, Fraser King, and Helen Leung. "The Development and Use of T2GGM: A Gas Modelling Code for the Postclosure Safety Assessment of OPG’s Proposed L&ILW Deep Geologic Repository, Canada." In ASME 2009 12th International Conference on Environmental Remediation and Radioactive Waste Management. ASMEDC, 2009. http://dx.doi.org/10.1115/icem2009-16291.

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As part of the postclosure safety assessment of Ontario Power Generation’s (OPG’s) proposed Deep Geologic Repository (DGR) for Low and Intermediate Level Waste (L&ILW) at the Bruce site, Ontario, a Gas Generation Model (GGM) has been developed and used to model the detailed generation of gas within the DGR due to corrosion and microbial degradation of the organics and metals present. The GGM is based on a kinetic description of the various microbial and corrosion processes that lead to the generation and consumption of various gases. It takes into account the mass-balance equations for each of the species included in the model, including three forms of organic waste (cellulose, ionexchange resins, and plastics and rubbers), four metallic waste forms and container materials (carbon and galvanised steel, passivated carbon steel, stainless steel and nickel-based alloys, and zirconium alloys), six gases (CO2, N2, O2, H2, H2S, and CH4), five terminal electron acceptors (O2, NO3−, Fe(III), SO42−, and CO2), five forms of biomass (aerobes, denitrifiers, iron reducers, sulphate reducers, and methanogens), four types of corrosion product (FeOOH, FeCO3, Fe3O4, and FeS), and water. The code includes the possibility of the limitation of both microbial and corrosion reactions by the availability of water. The GGM has been coupled with TOUGH2 to produce T2GGM; a code that models the generation of gas in the repository and its subsequent transport through the geosphere. T2GGM estimates the peak repository pressure, long time repository saturation and the total flux of gases from the geosphere. The present paper describes the development of T2GGM and the numerical modelling work undertaken to calculate the generation and build-up of gas in the repository, the two-phase exchange of gas and groundwater between the repository and the surrounding rock, and between the rock and the surface environment. The results have been used to inform the safety assessment modelling.
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