RESEARCH ON CHEMICAL INTERMEDIATES
·
2016
·Vol. 42
·期 10
·7345-7358
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IF 1.833
Wang Ruikun,Zhao Zhenghui,Liu Jianzhong,Lv Yukun,Ye Xuemin
Municipal wastewater sludge (hereafter, sludge) is economically recycled by mixing with coal to prepare slurry fuels, called coal sludge slurry (CSS). However, raw sludge needs to be pretreated before being prepared as CSS because of its high viscosity. Alkali and ultrasonication pretreatment can effectively disrupt the sludge flocs and improve slurrying performance. The alkali pretreatment method takes a long time but has a low cost, whereas the ultrasonication pretreatment method needs a high energy input but takes a short time. This study combined these two methods with complementary advantages to reduce the sludge pretreatment time and ultrasonication energy demand to improve the slurrying performance for sludge. Results showed that, compared with only alkali and only ultrasonication, the combined alkali and ultrasonication pretreatment method had stronger effects on reducing slurry viscosity. The characteristic viscosity η
c of CSS prepared by raw sludge was 1663.60 mPa s. It was reduced to 1033.44 and 1472.10 mPa s, respectively, after the sludge was only pretreated by NaOH and Ca(OH) 2 at a dosage of 10 % dry sludge (DS) for 2 h, while it was reduced to 1205.43 mPa s after the sludge was only pretreated by ultrasonication of 30 kJ/g DS. After combined pretreatment, η
c of CSS was reduced to 774.98 mPa s (NaOH of 10 % DS for 2 h + ultrasonication of 30 kJ/g DS) and 1083.24 mPa s (Ca(OH) 2 of 10 % DS for 2 h + ultrasonication of 30 kJ/g DS), respectively. Apparently, the combined method can effectively decrease the alkali dosage or the ultrasonication energy input.
研究领域:
环境科学
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能源工程
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DOI
高影响因子
CELLULOSE
·
2021
·Vol. 28
·期 16
·10127-10141
·
IF 5.044
Qi Benkun,Wang Zhenwu,Luo Jianquan,Wan Yinhua
As a cheap, biodegradable, and nontoxic chemical, choline chloride (ChCl) is widely used in animal feed. In this study, acid and alkali catalyzed ChCl pretreatments of corn stover (CS) were investigated. Compared with single aqueous ChCl pretreatment, H 2 SO 4 acidified aqueous ChCl pretreatment was more effective in removing lignin (69.5%) and xylan (84.9%). NaOH alkalified aqueous ChCl pretreatment demonstrated better performance of delignification (76.8%) but weaker capability of removing xylan (46.2%) than acidified aqueous ChCl pretreatment. Following enzymatic digestibility of pretreated CS, glucose yield from acidified ChCl pretreatment was 72.1%, significantly lower than that of alkalified ChCl pretreatment (89.4%). However, the highest glucose yield of 98.6% resulted from solitary alkali pretreatment. Correlation studies between change in physico-chemical properties of pretreated solids and corresponding enzymatic digestibility indicated high delignification and bigger cellulose crystallite size were mainly responsible for high enzymatic hydrolysis efficiency. Additionally, the properties of extracted lignin from single and combined pretreatments with ChCl and alkali or acid were analyzed. Acidified ChCl pretreatment increased, whereas alkaline ChCl pretreatment decreased molecular weight and phenolic hydroxyl groups of separated lignin in comparison to individual acid and alkali pretreatment. These findings would provide useful information in understanding biomass pretreatments with aqueous ChCl.
研究领域:
生物化学
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生物质能
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环境科学
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DOI
高影响因子
Bioresource Technology Reports
·
2019
·
IF 0
Yingxue Gong,Zhibin Fu,Menglian Liu,Yu Dai,Jianghai Lin,Zehuan Liu
The alkalis sodium ethoxide and calcium hydroxide were combined to pretreat the abundant agricultural waste sugarcane leaf (SCL). The pretreatment conditions were optimized using single factors and orthogonal array, and the results of material's chemical compositions and enzymatic hydrolysis were investigated. The optimized conditions were pretreating SCL with C 2 H 5 ONa:Ca(OH) 2 volume ratio of 4:1 at 121 °C for 30 min. Under these conditions, the lignin removal rate of SCL was 86.26%, while the total reducing sugars and total enzymatic efficiency of enzymatic hydrolysis could reach 14.82 g/L and 80.02% respectively. These pretreating and hydrolysis results were similar compared with those of SCL pretreated with strong base C 2 H 5 ONa alone. But the strong base dosage was saved 20% and the pretreatment time was shortened to 30 min. Therefore the combined alkali pretreatment could significantly save energy and reduce environmental pollution, which made it a promising method in large-scale production.
研究领域:
生物能源
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农业废弃物利用
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生物质转化
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DOI
BIORESOURCE TECHNOLOGY
·
2018
·
IF 5.807
Zhinan Wang,Xianfeng Hou,Jin Sun,Meng Li,Zhiyong Chen,Zhenzhong Gao
Two ultrasound-assisted pretreatment technologies, ultrasound-assisted alkaline and ultrasound-assisted aqueous ionic liquid tetrabutylammonium hydroxide ([TBA][OH]), are compared systematically in regard to enzymatic saccharification. Pretreated Eucalyptus samples were characterized by powder X-ray diffraction, 13 C cross polarization/magic-angle spinning solid state NMR spectroscopy, Fourier transform infrared spectroscopy, Scanning electron microscope (SEM) and chemistry composition analysis. These results not only explain the enzymatic saccharification difference between samples from the microstructure level, but also provide helpful information for relevant pretreatment research. Ultrasound-assisted [TBA][OH] pretreatment acquired a significant enhancement in the initial enzymatic rate of cellulose (79.39 mg/g/h), and a reducing sugar yield of 426.6 mg/g at 48 h. The pretreatment combining inexpensive aqueous ionic liquid and ultrasound may provide a promising strategy in the field of bio-refinery because of its unique advantages.
研究领域:
生物化学
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可再生资源技术
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DOI
PubMed
高影响因子
GREEN CHEMISTRY
·
2021
·Vol. 23
·期 8
·3081-3089
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IF 10.182
Alei Zhang,Chengyong Wang,Jie Chen,Guoguang Wei,Ning Zhou,Ganlu Li,Kequan Chen,Pingkai Ouyang
In this study, an alkali freeze–thaw pretreatment protocol was investigated to efficiently enhance enzymatic hydrolysis of chitin into N-acetyl glucosamine (GlcNAc) at high concentrations. The optimal conditions for alkali freeze–thaw treatment of chitin were determined to be an alkali concentration of 8% (w/v), a temperature of −25 °C, twice freeze–thaw cycles in 12 h, and a substrate concentration of 4% (w/v). This treatment caused chitin powder to acquire a visible fibrillar structure, with scanning electron microscopy and Brunauer–Emmett–Teller analysis showing that the surface of chitin changes from a dense structure to a nanofibrillar structure (diameter 30–50 nm) with increased surface areas after the treatment. Moreover, Fourier-transform infrared spectroscopy, thermogravimetric analysis, elemental analysis, X-ray diffraction, and intrinsic viscosity analysis revealed that the crystallinity, molecular weight, and thermal stability of the chitin decreased upon pretreatment without alteration of the chemical structure or deacetylation. Interestingly, facile recovery of the alkali solution can be realized after the precipitation of chitin via boiling and centrifugation, and the recovered alkali aqueous solution can be reused without decreasing the subsequent treatment effect. Additionally, the GlcNAc concentrations from the fed-batch enzymatic hydrolysis of chitin treated with KOH and NaOH can reach up to 75 g L−1 and 68 g L−1 over 18 h, respectively. Thus, this work demonstrates a clean, sustainable, and efficient procedure to convert chitin into GlcNAc.
研究领域:
生物化学
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材料科学
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环境科学
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DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2019
·
IF 4.784
Chao Xu,Jun Zhang,Yu Zhang,Ying Guo,Huijuan Xu,Cuiyi Liang,Zhongming Wang,Jingliang Xu
Sugarcane bagasse (SCB) was pretreated by sodium hydroxide (SH), alkaline ethanol (AE) and alkaline hydrogen peroxide (AHP), and the solid residue with similar lignin content after different pretreatment was selected. Enzymatic saccharification with different substrates was performed at 2%, 10%, and 20% ( w / v ) solid loading. After that, the lignin from different substrate was extracted and its structure was characterized. Furthermore, the adsorption capability of isolated lignin to cellulase and its effect on enzymatic hydrolysis were studied. The results showed that, as the substrate content increased from 2% (w/v) to 20% (w/v), the glucose yield after digestion of SH, AE, and AHP pretreated SCB reduced by 41.8%, 35.4%, and 28.7%, respectively. The inhibitory effect of different prepared lignin on the digestibility of Avicel was as follows, SH pretreated lignin (SHL) > cellulase enzymatic hydrolysis lignin (CEL) > AE pretreated lignin (AEL) > AHP pretreated lignin (AHPL), which exhibited positive correlation with its non-productive adsorption capability to cellulase. Lignin samples with low negative zeta potential , high hydrophobicity and high ration of syringyl (S) to guaiacyl (G) were unfavorable for the enzymatic saccharification of cellulose .
研究领域:
生物化学
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可再生资源工程
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DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
·
2020
·Vol. 44
·期 6
·4616-4628
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IF 3.741
Yunlong Zhou,Xiaoyuan Ye,Dongyao Lin
Summary In this study, alkali pretreated corn stover was added as a sacrificial agent to the suspension of Pt/TiO 2 to significantly enhanced photocatalytic hydrogen evolution. The changes in structural characteristics of corn stover before and after alkali treatment and photocatalytic reactions were studied. According to the results, the removal of lignin and hemicellulose, as well as the changes in surface morphology, structural components, and functional groups of alkali pretreated corn stover may affect the photocatalytic hydrogen production process. Next, the effects of NaOH concentration, pretreatment time and temperature on hydrogen production were also investigated. Among them, within the scope of the experimental conditions, the optimal hydrogen production is 25.84 μmol h −1 . Moreover, the enhancement of photocatalytic hydrogen production is also achieved by using the waste liquid of alkali pretreated. The output of this study may provide a reference for the reuse of alkali-treated biomass residues and waste liquor in some industries, and make more comprehensive, efficient and green use of native lignocellulosic biomass.
研究领域:
环境科学
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能源科学
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材料科学
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DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2024
·
IF 7.4
Shi-Yu Feng,Sheng Li,Wan-Zhao Huang,Qi Niu,Deng-Yu Chen,Zhi-Mo Fang,Li-Juan Gao,Kai Li,Qiang Lu
With the increasing demand for cellulose acetate (CA) in industrial and daily applications, the disposal of its waste has emerged as an environmental concern. In this study, a novel and sustainable method for value-added utilization of waste CA was proposed, which involved NaOH pretreatment and subsequent catalytic pyrolysis using phosphoric acid-activated carbon (PAC) to prepare levoglucosone (LGO). The effects of pretreatment temperatures and NaOH concentrations on the physicochemical characteristics of CA were thoroughly investigated. Furthermore, the pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) experiments were conducted to methodically assess the impacts of both pretreatment and pyrolysis conditions on the production of LGO. The results indicated that NaOH pretreatment could effectively hydrolyze the ester bonds in CA, leading to the removal of acetyl groups and a decrease in thermal stability. At a pretreatment temperature of 40 °C, a NaOH concentration of 0.5 mol/L, a catalyst/sample ratio of 1/3, and a pyrolysis temperature of 400 °C, the LGO yield could reach 11.52 wt%, much higher than that obtained from catalytic pyrolysis of CA (2.70 wt%). This study provides an efficient method for treating waste CA and demonstrates its potential for conversion into high-value chemicals, laying a solid foundation for the green recycling of waste plastics.
研究领域:
环境科学
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化学工程
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DOI
高影响因子
BIORESOURCE TECHNOLOGY
·
2012
·
IF 4.98
Fengcheng Li,Shuangfeng Ren,Wei Zhang,Zhengdan Xu,Guosheng Xie,Yan Chen,Yuanyuan Tu,Qing Li,Shiguang Zhou,Yu Li,Fen Tu,Lin Liu,Yanting Wang,Jianxiong Jiang,Jingping Qin,Shizhong Li,Qiwei Li,Hai-Chun Jing,Fasong Zhou,Neal Gutterson,Liangcai Peng
Xylans are the major hemicelluloses in grasses, but their effects on biomass saccharification remain unclear. In this study, we examined the 79 representative Miscanthus accessions that displayed a diverse cell wall composition and varied biomass digestibility . Correlation analysis showed that hemicelluloses level has a strong positive effect on lignocellulose enzymatic digestion after NaOH or H 2 SO 4 pretreatment. Characterization of the monosaccharide compositions in the KOH-extractable and non-KOH-extractable hemicelluloses indicated that arabinose substitution degree of xylan is the key factor that positively affects biomass saccharification. The xylose/arabinose ratio after individual enzyme digestion revealed that the arabinose in xylan is partially associated with cellulose in the amorphous regions, which negatively affects cellulose crystallinity for high biomass digestibility. The results provide insights into the mechanism of lignocellulose enzymatic digestion upon pretreatment, and also suggest a goal for the genetic modification of hemicelluloses towards the bioenergy crop breeding of Miscanthus and grasses.
研究领域:
植物学
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生物能源
·
遗传改良
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2016
·
IF 5.31
Guan-Yu Pan,Yu-Long Ma,Xiao-Xia Ma,Yong-Gang Sun,Jun-Min Lv,Jian-Li Zhang
Ni–W/MCM-41 as a non-noble metal catalyst for catalytic conversion of corn stalk pretreated with alkali into polyol was prepared by an impregnation method. The results showed that pretreatment corn stalk with alkali removed 41.79 wt% of hemicellulose and 60.21 wt% of lignin and thereby increased the content of cellulose from 41.13 wt% to 59.29 wt%. Data obtained from X-ray photoelectron spectra exhibited that there was an intense interaction between nickel and tungsten. Meanwhile, the Ni 17 W 3 alloy was evidenced by X-ray diffraction spectra. These were very beneficial to enhance the catalytic conversion of lignocellulose into polyol. The maximum yield of 71.37 wt% polyol was obtained by catalytic hydrogenation of lignocellulose to ethylene glycol and 1,2-propylene glycol utilizing 5%Ni–15%W/MCM-41 catalyst under H 2 pressure of 6 MPa and 250 °C for 2 h.
研究领域:
生物化学
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催化化学
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产品关联
DOI
高影响因子
FUEL
·
2014
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IF 3.406
Jing Yang,Jianchun Jiang,Ning Zhang,Chuncun Miao,Min Wei,Jian Zhao
This study examined the suitability of Sawtooth Oak ( Quercus acutissima ) shell waste as feedstock for bioethanol production for the first time. The impacts of varying parameters of dilute alkali pretreatment (temperature, time, and alkalinity) on enzymatic saccharification of oak shell were investigated. Results showed that the combination of 2% NaOH/121 °C (15 psi)/60 min achieved the highest delignification (39.34%) as well as the highest sugar release (426.36 mg/g pretreated material). In addition, optimal combination of 20 FPU cellulase, 20 CBU β-glucosidase and 1.5 FXU xylanase released total sugar yield that peaked at 653 mg/g pretreated material (613 mg glucose and 40 mg xylose). The maximum sugar recovered from the holocellulose fraction was 494.5 mg/g oak shell. This represents a conversion efficiency approaching 78.8% based on monomeric sugar recovery.
研究领域:
生物技术
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可再生能源
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产品关联
DOI
高影响因子
Water
·
2025
·Vol. 17
·期 4
·490
·
IF 3
Hao-Yang Ding,Si-Yu Wang,Thangavel Sangeetha,Min-Hua Cui
Triclosan (TCS) is extensively detected in wastewater and waste-activated sludge (WAS). The occurrence and fate of TCS in anaerobic digestion have been well revealed, but the change in TCS during WAS pretreatment needs to be clarified. Thermal hydrolysis pretreatment has been proven to be efficient for both WAS hydrolysis and TCS removal, with a removal efficiency of 54.0% and a retention time of 90 min at 170 °C. Alkaline pretreatment remarkably changed the TCS distribution between the sludge and liquid, and the solid–liquid distribution coefficient decreased by three orders of magnitude as the pH increased to 13. Neither alkaline pretreatment nor thermal–alkaline pretreatment resulted in the obvious removal of TCS. UP demonstrated limited efficiency in the hydrolysis of WAS, as well as the migration and removal of TCS. Thus, this study demonstrated that pretreatment methods and operational parameters significantly influence the migration and removal of TCS. It also provides a valuable reference for future studies on the migration and degradation behavior of TCS during anaerobic digestion and lays a foundation for the development of WAS treatment engineering capable of efficiently removing TCS.
研究领域:
环境科学
·
污水处理
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DOI
高影响因子
危险品化学品经营许可证（带存储）