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Search Results: 1 - 10 of 439 matches for " pretreatment "
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Effective of Microwave-KOH Pretreatment on Enzymatic Hydrolysis of Bamboo  [PDF]
Zhiqiang Li, Zehui Jiang, Benhua Fei, Yan Yu, Zhiyong Cai
Journal of Sustainable Bioenergy Systems (JSBS) , 2012, DOI: 10.4236/jsbs.2012.24015
Abstract: Bamboo, with its advantages of fast growth, short renovation, easy propagation and rich in cellulose and hemicellulose, is a potential feedstock for bioethanol or other biofuels production. The objective of this study was to examine the feasibility of microwave assistant KOH pretreatments to enhance enzymatic hydrolysis of bamboo. Pretreatment was carried out by immersing the bamboo in KOH (12% and 8% w/w bamboo) solutions and exposing the slurry to microwave radiation power of 400 W for 30min. Chemical composition of the pretreated substrates and spent liquor was analyzed. Pretreated substrates were enzymatic hydrolyzed, and glucose and xylose in the hydrolysate were analyzed. The results showed that the pretreated substrate with microwave assisted KOH had significantly higher sugar yield than the untreated samples. The fermentation inhibitors formic acid, furfural, HMF and levulinic acid were much lower than acid pretreatment reported.
Pretreatment of Wastewater Streams from Petroleum/Petrochemical Industries Using Coagulation  [PDF]
Hossam Altaher, Emad ElQada, Waid Omar
Advances in Chemical Engineering and Science (ACES) , 2011, DOI: 10.4236/aces.2011.14035
Abstract: Coagulation-flocculation processes using different types of conventional coagulants, namely, ferric chloride (FeCl3), aluminum sulfate (AL2(SO4)3·18H2O), lime and ferrous sulfate (FeSO4) were investigated using the Jar-test technique. A further aim is to determine the optimum conditions for the treatment of industrial wastewater effluents i.e. coagulant dosage, mixing rate, temperature and pH control. Under optimal condition of process parameters, coagulation/flocculation process was able to lower the turbidity well below the permissible level (1.8 NTU). The results indicate that ferric chloride had superior efficiency compared with other coagulants with efficient dose of 800 mg/l. The optimal initial pH of the effluents that enhanced the turbidity removal was 8.6. The temperature showed no significant effect on the turbidity removal.
Propyl-Sulfonic Acid Functionalized Nanoparticles as Catalyst for Pretreatment of Corn Stover  [PDF]
Leidy Pe?a, Feng Xu, Keith L. Hohn, Jun Li, Donghai Wang
Journal of Biomaterials and Nanobiotechnology (JBNB) , 2014, DOI: 10.4236/jbnb.2014.51002
Abstract:

Propyl-sulfonic (PS) acid-functionalized nanoparticles were synthesized, characterized and evaluated as catalysts for pretreatment of corn stover. Silica coated nanoparticles were functionalized with 0.5% mercaptopropyltrimethoxysilane (MPTMS) at neutral pH in a mixture of water and ethanol. Sulfur contents of the acid functionalized nanoparticles, measured in a CHNS analyzer, varied from 6%-10%, and the acid load ranged from 0.040 to 0.066 mmol H+/g. A Box-Behnken design was employed to calculate the minimum number experiments required to obtain an estimate of the surface response for temperature, catalyst load, and %S content of the catalyst. Pretreatment of corn stover was carried out at three temperature levels 160, 180, and 200°C for 1 h. Three levels of catalyst load were used 0.1, 0.2, and 0.3 g of catalyst per gram of biomass. Hydro-thermolysis controls were carried at each temperature level. The catalyst load did not have an effect on the glucose yield at 160°C, and the average glucose yield obtained at this temperature was 59.0%. The glucose yield was linearly correlated to the catalyst load during pretreatment at 180°C, and a maximum glucose yield of 90% was reached when using 0.2 g of PS nanoparticles that had a total sulfur content of 6.1%. Complete hydrolysis of glucose was reached at 200°C but the average xylose yield was 4.6%, and about 20.2% of the combined glucose and xylose were lost as hydroxymethylfurfural and furfural. Results showed that acid-functionalized nanoparticles can be potential catalysts

Energy Efficient Manufacturing of Nanocellulose by Chemo- and Bio-Mechanical Processes: A Review  [PDF]
Ashok K. Bharimalla, Suresh P. Deshmukh, Prashant G. Patil, Nadanathangam Vigneshwaran
World Journal of Nano Science and Engineering (WJNSE) , 2015, DOI: 10.4236/wjnse.2015.54021
Abstract: Nanocellulose is a new-age material derived from cellulosic biomass and has large specific surface area, high modulus and highly hydrophilic in nature. It comprises of two structural forms viz., nanofibrillated cellulose (NFC) and nanocrystalline cellulose (NCC). This review provides a critical overview of the recent methods of bio- and chemo-mechanical processes for production of nanocellulose, their energy requirements and their functional properties. More than a dozen of pilot plants/commercial plants are under operation mostly in the developed countries, trying to exploit the potential of nanocellulose as reinforcing agent in paper, films, concrete, rubber, polymer films and so on. The utilization of nanocellulose is restricted mainly due to initial investment involved, high production cost and lack of toxicological information. This review focuses on the current trend and exploration of energy efficient and environment-friendly mechanical methods using pretreatments (both chemical and biological), their feasibility in scaling up and the future scope for expansion of nanocellulose application in diverse fields without impacting the environment. In addition, a nanocellulose quality index is derived to act as a guide for application based screening of nanocellulose production protocols.
A Review on 1st and 2nd Generation Bioethanol Production-Recent Progress  [PDF]
Radhakumari Muktham, Suresh K. Bhargava, Satyavathi Bankupalli, Andrew S. Ball
Journal of Sustainable Bioenergy Systems (JSBS) , 2016, DOI: 10.4236/jsbs.2016.63008
Abstract: Today’s society is based on the use of fossil resources for transportation fuels. The result of unlimited consumption of fossil fuels is a severe depletion of the natural reserves and damage to the environment. Depleting fossil reserves and increasing demand for energy together with environmental concerns have motivated researchers towards the development of alternative fuels which are eco-friendly, renewable and economical. Bioethanol is one such dominant global renewable transport biofuel which can readily substitute fossil fuels. Conventionally, bioethanol has been produced from sucrose and starch rich feedstocks (edible agricultural crops and products) known as 1st generation bioethanol; however this substrate conflicts with food and feed production. As an alternative to 1st generation bioethanol, currently there is much focus on advancing a cellulosic bioethanol concept that utilizes lignocellulosic residues from agricultural crops and residues (such as bagasse, straw, stover, stems, leaves and deoiled seed residues). Efficient conversion of lignocellulosic biomass into bioethanol remains an area of active research in terms of pretreatment of the biomass to fractionate its constituents (cellulose, hemicellulose and lignin), breakdown of cellulose and hemicellulose into hexose and pentose sugars and co-fermentation of the sugars to ethanol. The present review discusses research progress in bioethanol production from sucrose, starch and cellulosic feedstocks. Development of efficient technology to convert lignocellulosic biomass into fermentable sugars and optimization of enzymatic hydrolysis using on-site/ in-house enzyme preparation are the key areas of development in lignocellulosic bioethanol production. Moreover, finding efficient fermenting microorganisms which can utilize pentose and hexose sugars in their metabolism to produce ethanol together with minimum foam and glycerol formation is also an important parameter in fermentation. Research has been focusing on the application of genetically modified strains, thermoanaerobes and mixed cultures of different strains in bioethanol production from sucrose, starch and lignocellulosic feedstocks.
Multi-Scale Structural Studies of Sequential Ionic Liquids and Alkali Pretreated Corn Stover and Sugarcane Bagasse  [PDF]
Ishwinder Kaur, Girish Sahni
Green and Sustainable Chemistry (GSC) , 2018, DOI: 10.4236/gsc.2018.81007
Abstract: The complexity of plant cell walls impedes the conversion of cellulosic biomass to sugars. Pretreatment becomes a necessity to increase the digestibility of biomass. An in-depth understanding of the structure and underlying mechanisms governing deconstruction process is important. In the present study, the comprehensive investigation of morphological and structural changes in corn stover and sugarcane bagasse following ionic liquids dissolution and alkaline extraction was done using Fourier transform infrared spectroscopy, Thermogravimetric analysis, Confocal scanning laser microscopy, Atomic force microscopy and Dynamic light scattering studies. Both the substrates were pretreated with ILs 1-ethyl-3-methylimidazolium acetate and 1-butyl-3-methylimidazolium acetate followed by alkaline extraction. The pronounced changes such as lignin, hemicelluloses removal and decreased cellulose crystallinity after the pretreatments lead to the structural transformation of matrix polymers. The enzymatic hydrolysis showed 90% theoretical sugar yield in case of sugarcane bagasse and 80% in corn stover following synergistically combined pretreatments.
Drying kinetics of bananas by natural convection: Influence of temperature, shape, blanching and cultivar
Borges, Soraia Vilela;Mancini, Maurício C.;Corrêa, Jefferson Luiz Gomes;Leite, Julia Benedito;
Ciência e Agrotecnologia , 2011, DOI: 10.1590/S1413-70542011000200019
Abstract: the influence of variables as temperature, solid shape, temperature, branching and cultivar on drying of bananas were studied. bananas from cv. prata and d'água, on disk and cylindrical shape, blanched or not, were dehydrated in a tray dryer in natural convection at 40 and 70oc. drying behavior was analyzed by using a mathematical model. the exponential model showed good agreement to experimental data (r2 0.93 - 0.99 and standard error: 0.01- 0.05). temperature presented positive influence on drying rate in all the tested conditions. with respect to the sample shape, the disk shape carried out to significantly higher drying rates only for d'água cultivar without blanching. blanching was significantly influent, with positive influence, on drying rate of banana cv. prata at 40o c. the influence of the cultivar did not present a defined tendency.
Avalia??o do processo de impregna??o a vácuo em mel?o, utilizando diferentes substancias
Reno, Marciu José;Resende, Jaime Vilela de;Prado, M?nica Elisabeth Torres;
Ciência e Agrotecnologia , 2010, DOI: 10.1590/S1413-70542010000500027
Abstract: cylindrical cuts of melon (cucumis melo var inodorus naudin, yellow type) were submitted to impregnation with calcium chloride solutions (0.5 g.100 ml-1 of solution) added with gelatinized starch (0. 5 and 10 g.100 ml-1 of solution) and glucose (0. 10 and 20 g.100 ml-1 of solution) with controlled vacuum pressure (84.4; 50.5 and 16.6 kpa). measurements of the total soluble solids, incorporation or loss components (turgidity) and texture of melon slices were made before and after vacuum impregnation. quality parameter variations were calculated in relation to the original fruit. alterations in the viscosity of the solutions during the processing had been also quantified. the existence of synergistic processes between the solute flows from the fruit and from the solution was evident and could be analyzed using response surfaces for the different pressures as a function of the glucose and gelatinized starch concentrations in the solutions. the molecular mobility of components of the fruit and the solution related to viscosity was discussed.
Caracteriza??o de subproduto da indústria de alumínio e seu uso na reten??o de cádmio e chumbo em sistemas monoelementares
Costa, Enio Tarso de Souza;Guilherme, Luiz Roberto Guimar?es;Curi, Nilton;Lopes, Guilherme;Visioli, Elton Luiz;Oliveira, Luiz Carlos Alves de;
Química Nova , 2009, DOI: 10.1590/S0100-40422009000400008
Abstract: the present work aimed to characterize an aluminum industry by-product in natura (l.a. nat) and after phosphate and thermal pretreatments; evaluate the adsorption/desorption capacity of cd and pb by this l.a. nat form and after the aforementioned pretreatments, comparing them with an in natura iron mining by-product (l.f. nat). the l.a. nat presented a high ph as well as a high na concentration and also an oxide-rich mineralogy. pretreatment of the by-product had no significant effect upon cd and pd adsorption/desorption. the l.a. nat performed better than the l.f. nat as an cd and pb adsorbent.
Ethanol production from corn stover pretreated by electrolyzed water and a two-step pretreatment method
XiaoJuan Wang,Hao Feng,ZhiYi Li
Chinese Science Bulletin , 2012, DOI: 10.1007/s11434-012-5079-1
Abstract: Pretreatment is one of the most important unit operations for ethanol production from biomass feedstocks. In this study, corn stover was used as a feedstock to examine the effectiveness of two pretreatments: electrolyzed water pretreatment and a two-step pretreatment. Electrolyzed water was employed as a catalyst to conduct one-step pretreatment of corn stover at three temperatures (165, 180 and 195°C) and three treatment times (10, 20 and 30 min). During the two-step pretreatment process, an organic alkaline solution of 1% (w/w) NaOH in 70% (w/w) ethanol was used for lignin removal in the first step, followed by a second step using hot water. No furfural or 5-hydroxymethyl furfural was detected in the hydrolysates from both pretreatment methods when the detection limit of the HPLC was 0.2 g/L. The highest glucan conversion yields were 83% obtained at 195°C for 30 min with acidic electrolyzed water and 83% by the two-step process, where the second step of the pretreatment was at 135°C for 30 min. The hydrolyzates from the two pretreatment methods showed good performance in Saccharomyces cerevisiae fermentation tests. The two new methods may provide promising alternatives for the pretreatment of biomass for ethanol production.
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