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Dehua Liu - One of the best experts on this subject based on the ideXlab platform.
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production of pulp ethanol and lignin from sugarcane bagasse by alkali Peracetic Acid delignification
Biomass & Bioenergy, 2011Co-Authors: Xuebing Zhao, Dehua LiuAbstract:A two-stage process for delignification of sugarcane bagasse with alkali and Peracetic Acid (PAA) to produce of pulp, ethanol and lignin products was reported. By this process, sugarcane bagasse can be converted to high-quality pulp, ethanol and lignin products under mild conditions. The obtained pulp had higher brightness and superior strength properties than corresponding kraft pulp. The pulp was also very easy to digest by cellulase, and well suitable for simultaneous saccharification fermentation (SSF) to produce ethanol. The obtained lignins were characterized by several chemical and instrumental analyses. It was found that PAA lignin had higher oxygen content and lower molecular weight. This process is environment-friendly because no sulfur and chlorine were introduced and less wastewater was let. It also can be easily fulfilled by improving a conventional pulping mill based on the existing equipments.
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Peracetic Acid pretreatment of sugarcane bagasse for enzymatic hydrolysis a continued work
Journal of Chemical Technology & Biotechnology, 2008Co-Authors: Xuebing Zhao, Lei Wang, Dehua LiuAbstract:Previous work has shown that the enzymatic hydrolysis of sugarcane bagasse could be greatly enhanced by Peracetic Acid (PAA) pretreatment. There are several factors affecting the enzymatic digestibility of the biomass, including lignin and hemicelluloses content, cellulose crystallinity, acetyl group content, accessible surface area and so on. The objective of this work is to analyze the mechanism of the enhancement of enzymatic digestibility caused by PAA pretreatment. Delignification resulted in an increase of the surface area and reduction of the irreversible absorption of cellulase, which helped to increase the enzymatic digestibility. The Fourier transform infrared (FTIR) spectrum showed that the absorption peaks of aromatic skeletal vibrations were weakened or disappeared after PAA pretreatment. However, the infrared crystallization index (N.O'KI) was increased. X-ray diffraction (XRD) analysis indicated that the crystallinity of PAA-treated samples was increased owing to the partial removal of amorphous lignin and hemicelluloses and probable physical change of cellulose. The effect of acetyl group content on enzymatic digestibility is negligible compared with the degree of delignification and crystallinity. The results indicate that enhancement of enzymatic digestibility of sugarcane bagasse by PAA pretreatment is achieved mainly by delignification and an increase in the surface area and exposure of cellulose fibers.
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preparation of Peracetic Acid from hydrogen peroxide part ii kinetics for spontaneous decomposition of Peracetic Acid in the liquid phase
Journal of Molecular Catalysis A-chemical, 2008Co-Authors: Xuebing Zhao, Keke Cheng, Junbin Hao, Dehua LiuAbstract:A homogeneous kinetic model was developed for describing the synthesis, hydrolysis and spontaneous decomposition of Peracetic Acid (PAA) in the liquid phase under an Acid condition. It was found that the chelant (diethylenetriaminepenta acetic Acid, DTPA) was not so effective for reduction of PAA decomposition in a strong Acid solution as it in a neutral or alkaline aqueous solution. The expressions for calculating the rate constants of PAA synthesis and hydrolysis obtained in our previous work were still appropriate at a high temperature. The spontaneous decomposition of PAA under an Acid condition was an observed second-order reaction with respect to PAA concentration. The observed rate constant was a relatively complicated function of temperature and H + concentration. Addition of sulfuric Acid could significantly decrease the PAA decomposition. The reaction mechanism was investigated. It was proved that the rate-determining step for the spontaneous decomposition of PAA was the reaction between PAA molecule and a proton-activated carbonyl intermediary. The application of the kinetic model was further discussed. © 2008 Elsevier B.V. All rights reserved.
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effect of several factors on Peracetic Acid pretreatment of sugarcane bagasse for enzymatic hydrolysis
Journal of Chemical Technology & Biotechnology, 2007Co-Authors: Xuebing Zhao, Lei Wang, Dehua LiuAbstract:BACKGROUND: Lignocellulose should undergo pretreatment to enhance its enzymatic digestibility before being saccharified. Peracetic Acid (PAA) is a strong oxidant that can remove lignin under mild conditions. The sulfuric Acid in the PAA solution also can cause degradation of hemicelluloses. The objective of the present work is to investigate the effect of several factors on Peracetic Acid pretreatment of sugarcane bagasse. RESULTS: It was found that PAA charge, liquid/solid (l/s) ratio, temperature, time, interactions between PAA charge and l/s ratio, temperature and time, all had a very significant effect on the enzymatic conversion ratio of cellulose. The relative optimum condition was obtained as follows: PAA charge 50%, l/s ratio 6:1, temperature 80 °C and time 2 h. More than 80% of the cellulose in bagasse treated under the above conditions was converted to glucose by cellulase of 20 FPU g−1 cellulose. Compared with H2SO4 and NaOH pretreatments under the same mild conditions, PAA pretreatment was the most effective for enhancement of enzymatic digestibility. CONCLUSION: PAA pretreatment could greatly enhance the enzymatic digestibility of sugarcane bagasse by removing hemicelluloses and lignin, but removal of lignin was more helpful. This study can serve as a step to further optimization of PAA pretreatment and understanding the mechanism of enhancement of enzymatic digestibility. Copyright © 2007 Society of Chemical Industry
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preparation of Peracetic Acid from hydrogen peroxide part i kinetics for Peracetic Acid synthesis and hydrolysis
Journal of Molecular Catalysis A-chemical, 2007Co-Authors: Xuebing Zhao, Ting Zhang, Yujie Zhou, Dehua LiuAbstract:Abstract A homogeneous kinetic model for preparation of Peracetic Acid (PAA) from acetic Acid (AA) and hydrogen peroxide (HP) under the catalysis ofsulfuric Acid (SA) in the liquid phase was investigated. The kinetic equations of PAA synthesis and hydrolysis were given and the kinetic constantswere estimated according to the experimental data by a simplex optimization method. It was found that the synthesis and hydrolysis of PAA wereboth first-order reactions with respect to reactant concentrations and H + concentration. Linear relationships were discovered between the observedrate constants and H + concentrations at a certain temperature, with the slopes being corresponding intrinsic rate constants. The intrinsic activationenergies of PAA synthesis and hydrolysis were 57.8 and 60.4kJmol −1 , respectively. The mechanisms of PAA synthesis and hydrolysis werediscussed. It has been proved that the rate-determining step in the synthesis of PAA is the reaction between H 2 O 2 with active carbonyl intermediary,and in the hydrolysis of PAA the reaction between water and corresponding active carbonyl intermediary.© 2007 Elsevier B.V. All rights reserved.
Xuebing Zhao - One of the best experts on this subject based on the ideXlab platform.
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production of pulp ethanol and lignin from sugarcane bagasse by alkali Peracetic Acid delignification
Biomass & Bioenergy, 2011Co-Authors: Xuebing Zhao, Dehua LiuAbstract:A two-stage process for delignification of sugarcane bagasse with alkali and Peracetic Acid (PAA) to produce of pulp, ethanol and lignin products was reported. By this process, sugarcane bagasse can be converted to high-quality pulp, ethanol and lignin products under mild conditions. The obtained pulp had higher brightness and superior strength properties than corresponding kraft pulp. The pulp was also very easy to digest by cellulase, and well suitable for simultaneous saccharification fermentation (SSF) to produce ethanol. The obtained lignins were characterized by several chemical and instrumental analyses. It was found that PAA lignin had higher oxygen content and lower molecular weight. This process is environment-friendly because no sulfur and chlorine were introduced and less wastewater was let. It also can be easily fulfilled by improving a conventional pulping mill based on the existing equipments.
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enhancement of the enzymatic digestibility of sugarcane bagasse by alkali Peracetic Acid pretreatment
Enzyme and Microbial Technology, 2009Co-Authors: Xuebing Zhao, Feng Peng, Keke ChengAbstract:Abstract The enzymatic digestibility of sugarcane bagasse was greatly increased by alkali (NaOH)–Peracetic Acid (PAA) pretreatment under mild conditions. The effects of several factors affecting the pretreatment were investigated. It was found that when bagasse was pre-pretreated by 10% (based on initial dry materials) NaOH with 3:1 liquid-to-solid ratio at 90 °C for 1.5 h and further delignified by 10% Peracetic Acid (based on initial dry materials) at 75 °C for 2.5 h, the yield of reducing sugars reached 92.04% by enzymatic hydrolysis for 120 h with cellulase loading of 15 FPU/g solid. Compared with Acid and alkali pretreatment, alkali–PAA pretreatment could be conducted under milder conditions and was more effective for delignification with less carbohydrates being degraded in the pretreatment process. Alkaline stage played an important role for partial delignification, swelling fibers and subsequently reducing PAA loading. No loss of cellulase activity (FPA) was observed in the liquid phase for alkali–PAA pretreated bagasse after enzymatic hydrolysis for 120 h.
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Peracetic Acid pretreatment of sugarcane bagasse for enzymatic hydrolysis a continued work
Journal of Chemical Technology & Biotechnology, 2008Co-Authors: Xuebing Zhao, Lei Wang, Dehua LiuAbstract:Previous work has shown that the enzymatic hydrolysis of sugarcane bagasse could be greatly enhanced by Peracetic Acid (PAA) pretreatment. There are several factors affecting the enzymatic digestibility of the biomass, including lignin and hemicelluloses content, cellulose crystallinity, acetyl group content, accessible surface area and so on. The objective of this work is to analyze the mechanism of the enhancement of enzymatic digestibility caused by PAA pretreatment. Delignification resulted in an increase of the surface area and reduction of the irreversible absorption of cellulase, which helped to increase the enzymatic digestibility. The Fourier transform infrared (FTIR) spectrum showed that the absorption peaks of aromatic skeletal vibrations were weakened or disappeared after PAA pretreatment. However, the infrared crystallization index (N.O'KI) was increased. X-ray diffraction (XRD) analysis indicated that the crystallinity of PAA-treated samples was increased owing to the partial removal of amorphous lignin and hemicelluloses and probable physical change of cellulose. The effect of acetyl group content on enzymatic digestibility is negligible compared with the degree of delignification and crystallinity. The results indicate that enhancement of enzymatic digestibility of sugarcane bagasse by PAA pretreatment is achieved mainly by delignification and an increase in the surface area and exposure of cellulose fibers.
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preparation of Peracetic Acid from hydrogen peroxide part ii kinetics for spontaneous decomposition of Peracetic Acid in the liquid phase
Journal of Molecular Catalysis A-chemical, 2008Co-Authors: Xuebing Zhao, Keke Cheng, Junbin Hao, Dehua LiuAbstract:A homogeneous kinetic model was developed for describing the synthesis, hydrolysis and spontaneous decomposition of Peracetic Acid (PAA) in the liquid phase under an Acid condition. It was found that the chelant (diethylenetriaminepenta acetic Acid, DTPA) was not so effective for reduction of PAA decomposition in a strong Acid solution as it in a neutral or alkaline aqueous solution. The expressions for calculating the rate constants of PAA synthesis and hydrolysis obtained in our previous work were still appropriate at a high temperature. The spontaneous decomposition of PAA under an Acid condition was an observed second-order reaction with respect to PAA concentration. The observed rate constant was a relatively complicated function of temperature and H + concentration. Addition of sulfuric Acid could significantly decrease the PAA decomposition. The reaction mechanism was investigated. It was proved that the rate-determining step for the spontaneous decomposition of PAA was the reaction between PAA molecule and a proton-activated carbonyl intermediary. The application of the kinetic model was further discussed. © 2008 Elsevier B.V. All rights reserved.
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effect of several factors on Peracetic Acid pretreatment of sugarcane bagasse for enzymatic hydrolysis
Journal of Chemical Technology & Biotechnology, 2007Co-Authors: Xuebing Zhao, Lei Wang, Dehua LiuAbstract:BACKGROUND: Lignocellulose should undergo pretreatment to enhance its enzymatic digestibility before being saccharified. Peracetic Acid (PAA) is a strong oxidant that can remove lignin under mild conditions. The sulfuric Acid in the PAA solution also can cause degradation of hemicelluloses. The objective of the present work is to investigate the effect of several factors on Peracetic Acid pretreatment of sugarcane bagasse. RESULTS: It was found that PAA charge, liquid/solid (l/s) ratio, temperature, time, interactions between PAA charge and l/s ratio, temperature and time, all had a very significant effect on the enzymatic conversion ratio of cellulose. The relative optimum condition was obtained as follows: PAA charge 50%, l/s ratio 6:1, temperature 80 °C and time 2 h. More than 80% of the cellulose in bagasse treated under the above conditions was converted to glucose by cellulase of 20 FPU g−1 cellulose. Compared with H2SO4 and NaOH pretreatments under the same mild conditions, PAA pretreatment was the most effective for enhancement of enzymatic digestibility. CONCLUSION: PAA pretreatment could greatly enhance the enzymatic digestibility of sugarcane bagasse by removing hemicelluloses and lignin, but removal of lignin was more helpful. This study can serve as a step to further optimization of PAA pretreatment and understanding the mechanism of enhancement of enzymatic digestibility. Copyright © 2007 Society of Chemical Industry
Lijuan Wang - One of the best experts on this subject based on the ideXlab platform.
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an environmentally safe and nondestructive process for bleaching birch veneer with Peracetic Acid
Journal of Cleaner Production, 2015Co-Authors: Tieqiang Liang, Lijuan WangAbstract:Abstract The industrial production of dyed wood veneers is increasing significantly. The bleaching process prior to dyeing is a key step. An effective and nondestructive process was developed in this work for bleaching the birch veneer by Peracetic Acid. The effects of bleaching parameters, such as whiteness increase, weight lose rate, dimensional stability and surface wettability were investigated, as well as a comparison of different bleaching processes with hydrogen peroxide and sodium hypochlorite as bleaching agents. Fourier transform infrared spectrum and Scanning electron microscope were used to characterize the bleached veneers. The obtained bleaching conditions are as follows: Peracetic Acid 10 g/L, sodium pyrophosphate 0.4 g/L, pH 6.5, material to liquor ratio 1:20, at 65 °C for 1 h. The whiteness increase from Peracetic Acid bleaching is a little lower than that of hydrogen peroxide bleaching, but far higher than that of sodium hypochlorite bleaching. The weight lose rate of veneers bleached with Peracetic Acid is only 1.74%, far lower than those with hydrogen peroxide and sodium hypochlorite. And the dimensional change sequence is Peracetic Acid Peracetic Acid bleaching is advantageous for wood and is a promise method for commercial production. The present work can help to make technical innovations in wood bleaching process .
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an environmentally safe and nondestructive process for bleaching birch veneer with Peracetic Acid
Journal of Cleaner Production, 2015Co-Authors: Tieqiang Liang, Lijuan WangAbstract:Abstract The industrial production of dyed wood veneers is increasing significantly. The bleaching process prior to dyeing is a key step. An effective and nondestructive process was developed in this work for bleaching the birch veneer by Peracetic Acid. The effects of bleaching parameters, such as whiteness increase, weight lose rate, dimensional stability and surface wettability were investigated, as well as a comparison of different bleaching processes with hydrogen peroxide and sodium hypochlorite as bleaching agents. Fourier transform infrared spectrum and Scanning electron microscope were used to characterize the bleached veneers. The obtained bleaching conditions are as follows: Peracetic Acid 10 g/L, sodium pyrophosphate 0.4 g/L, pH 6.5, material to liquor ratio 1:20, at 65 °C for 1 h. The whiteness increase from Peracetic Acid bleaching is a little lower than that of hydrogen peroxide bleaching, but far higher than that of sodium hypochlorite bleaching. The weight lose rate of veneers bleached with Peracetic Acid is only 1.74%, far lower than those with hydrogen peroxide and sodium hypochlorite. And the dimensional change sequence is Peracetic Acid
Keke Cheng - One of the best experts on this subject based on the ideXlab platform.
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enhancement of the enzymatic digestibility of sugarcane bagasse by alkali Peracetic Acid pretreatment
Enzyme and Microbial Technology, 2009Co-Authors: Xuebing Zhao, Feng Peng, Keke ChengAbstract:Abstract The enzymatic digestibility of sugarcane bagasse was greatly increased by alkali (NaOH)–Peracetic Acid (PAA) pretreatment under mild conditions. The effects of several factors affecting the pretreatment were investigated. It was found that when bagasse was pre-pretreated by 10% (based on initial dry materials) NaOH with 3:1 liquid-to-solid ratio at 90 °C for 1.5 h and further delignified by 10% Peracetic Acid (based on initial dry materials) at 75 °C for 2.5 h, the yield of reducing sugars reached 92.04% by enzymatic hydrolysis for 120 h with cellulase loading of 15 FPU/g solid. Compared with Acid and alkali pretreatment, alkali–PAA pretreatment could be conducted under milder conditions and was more effective for delignification with less carbohydrates being degraded in the pretreatment process. Alkaline stage played an important role for partial delignification, swelling fibers and subsequently reducing PAA loading. No loss of cellulase activity (FPA) was observed in the liquid phase for alkali–PAA pretreated bagasse after enzymatic hydrolysis for 120 h.
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preparation of Peracetic Acid from hydrogen peroxide part ii kinetics for spontaneous decomposition of Peracetic Acid in the liquid phase
Journal of Molecular Catalysis A-chemical, 2008Co-Authors: Xuebing Zhao, Keke Cheng, Junbin Hao, Dehua LiuAbstract:A homogeneous kinetic model was developed for describing the synthesis, hydrolysis and spontaneous decomposition of Peracetic Acid (PAA) in the liquid phase under an Acid condition. It was found that the chelant (diethylenetriaminepenta acetic Acid, DTPA) was not so effective for reduction of PAA decomposition in a strong Acid solution as it in a neutral or alkaline aqueous solution. The expressions for calculating the rate constants of PAA synthesis and hydrolysis obtained in our previous work were still appropriate at a high temperature. The spontaneous decomposition of PAA under an Acid condition was an observed second-order reaction with respect to PAA concentration. The observed rate constant was a relatively complicated function of temperature and H + concentration. Addition of sulfuric Acid could significantly decrease the PAA decomposition. The reaction mechanism was investigated. It was proved that the rate-determining step for the spontaneous decomposition of PAA was the reaction between PAA molecule and a proton-activated carbonyl intermediary. The application of the kinetic model was further discussed. © 2008 Elsevier B.V. All rights reserved.
Carlos Henrique Gomes Martins - One of the best experts on this subject based on the ideXlab platform.
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in vitro studies of the antibacterial activity of copaifera spp oleoresins sodium hypochlorite and Peracetic Acid against clinical and environmental isolates recovered from a hemodialysis unit
Antimicrobial Resistance and Infection Control, 2018Co-Authors: Rosimara G L Vieira, Thais Da Silva Moraes, Larissa De Oliveira Silva, Thamires Chiquini Bianchi, Rodrigo Cassio Sola Veneziani, Sergio R Ambrosio, Jairo Kenupp Bastos, Regina Helena Pires, Carlos Henrique Gomes MartinsAbstract:Patients submitted to hemodialysis therapy are more susceptible to infection, especially to infection by Gram-positive bacteria. Various research works have attempted to discover new antimicrobial agents from plant extracts and other natural products. The present study aimed to assess the antibacterial activities of Copaifera duckei, C. reticulata, and C. oblongifolia oleoresins; sodium hypochlorite; and Peracetic Acid against clinical and environmental isolates recovered from a Hemodialysis Unit. The Minimum Inhibitory Concentration and the Fractionated Inhibitory Concentration Index were determined; the ability of the tested compounds/extracts to inhibit biofilm formation was evaluated by calculating the MICB50 and IC50. C. duckei was the most efficient among the assayed Copaifera species, and its oleoresin was more effective than Peracetic Acid and sodium hypochlorite. Copaifera oleoresins and disinfectants did not act synergistically at any of the tested combinations. Certain of C. duckei oleoresin, Peracetic Acid, and sodium hypochlorite concentrations inhibited biofilm formation and eradicated 50% of the biofilm population. C. duckei oleoresin is a potential candidate for disinfectant formulations. Based on these results and given the high incidence of multi-resistant bacteria in hemodialysis patients, it is imperative that new potential antibacterial agents like C. duckei oleoresin, which is active against Staphylococcus, be included in disinfectant formulations.
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In vitro studies of the antibacterial activity of Copaifera spp. oleoresins, sodium hypochlorite, and Peracetic Acid against clinical and environmental isolates recovered from a hemodialysis unit
BMC, 2018Co-Authors: Rosimara G L Vieira, Thais Da Silva Moraes, Larissa De Oliveira Silva, Thamires Chiquini Bianchi, Rodrigo Cassio Sola Veneziani, Sergio R Ambrosio, Jairo Kenupp Bastos, Regina Helena Pires, Carlos Henrique Gomes MartinsAbstract:Abstract Background Patients submitted to hemodialysis therapy are more susceptible to infection, especially to infection by Gram-positive bacteria. Various research works have attempted to discover new antimicrobial agents from plant extracts and other natural products. Methods The present study aimed to assess the antibacterial activities of Copaifera duckei, C. reticulata, and C. oblongifolia oleoresins; sodium hypochlorite; and Peracetic Acid against clinical and environmental isolates recovered from a Hemodialysis Unit. The Minimum Inhibitory Concentration and the Fractionated Inhibitory Concentration Index were determined; the ability of the tested compounds/extracts to inhibit biofilm formation was evaluated by calculating the MICB50 and IC50. Results C. duckei was the most efficient among the assayed Copaifera species, and its oleoresin was more effective than Peracetic Acid and sodium hypochlorite. Copaifera oleoresins and disinfectants did not act synergistically at any of the tested combinations. Certain of C. duckei oleoresin, Peracetic Acid, and sodium hypochlorite concentrations inhibited biofilm formation and eradicated 50% of the biofilm population. Conclusion C. duckei oleoresin is a potential candidate for disinfectant formulations. Based on these results and given the high incidence of multi-resistant bacteria in hemodialysis patients, it is imperative that new potential antibacterial agents like C. duckei oleoresin, which is active against Staphylococcus, be included in disinfectant formulations
