被引排行
Study on Preparation of Nano-Crystalline Cellulose from Hydrolysis by Cellulase
JIANG Ling-ling,CHEN Xiao-quan,LI Zong-ren (State Key Laboratory of Pulp and Paper Engineering,South China University of Technology,Guangzhou 510640,China)The method of preparing nano-crystalline cellulose(NCC) using cellulase made from cotton fibers,with prior treatment by ultrasonic cell pulverizer is studied.The optimum technological conditions are determined as follows: the pH value 4.8,the reaction temperature 45℃,the ratio of cellulase to substrate 8(mL∶g),the reaction time 2 d.The production has a good monodispersity at above conditions.
Research Advance on Preparation of Gallic Acid from Chinese Nutgall
ZHAO La(Guizhou Science-Technology Engineering Vocational College,Guiyang 550003,China)Tannin,a kind of ester made of gallic acid and polyols,easily hydrolyzes at the catalysis of acid,alkali or enzymes.Furthurmore,derivatives of gallic acid can be prepared.There are chemical methods and biological methods of preparing gallic acid from Chinese nutgall.Compared with chemical methods,the outstanding characteristics of the biological methods are the fully hydrolysis of Chinese nutgall and the utilization of by product(glucose) as energy source and carbon source,which not only improve the utilization efficiency of resource,but also are benefit for environment protection.
Study on the Extraction of Polysaccharides from Ginseng with Ultrasonic Wave
ZHONG Zhen-sheng,SUN Li-jie,FENG Yan,MU Xiao-mei(School of Chemical Science,South China University of Technology,Guangzhou 510640,China)Using distilled water as extraction agent,ginseng polysaccharides were extracted by method of ultrasonic wave from ginseng powder.The content of ginseng polysaccharides was determined by the method of phenol-vitriol.Compared with the routine method,the content of ginseng polysaccharides was enhanced by ultrasonic process at fixed 200 W,30 min,m(ginseng powder)∶m(distilled water) =1∶50,grainsize 80 mesh,and the enhancement rate was 2.3%.
Toxicity Study of Ammonium on Methanogenic Bacteria in Anaerobic Granular Sludge
YU Fang-fang,WU Jian-dong(College of Environmental Science and Engineering,South China University of Technology,Guangzhou 510006,China)The toxicity of ammonium on methanogenic bacteria in anaerobic granular sludge was investigated using intermittent experiments under the condition of medium temperature of(35±1)℃,with glucose as organic carbon source.The experiment results showed that,when COD was 6000 mg·L-1,the methanogenic bacteria were inhibited at the ammonium concentration of 1500 mg·L-1 with the corresponding IC50 of 4000 mg·L-1 and the periodical maximal methanogenic velocity of 92 mL·h-1,and the average ammonium removal rate was 13.17%.When the high concentration of ammonium was removed,the methanogenic activity recovered in varying degrees,and the smaller the inhibition,the faster the recovery of methanogenic activity of sludge.Furthermore,the results also indicated that,when alkalinity and sludge concentration being enhanced,the toxicity of ammonium on methanogenic bacteria in anaerobic granular sludge decreased.
Effect of Chemical Pretreatment on Enzymatic Saccharification of Maize Straw
SONG An-dong 1,2 ,REN Tian-bao 2,3 , XIE Hui 1 ,PEI Guang-qing 1 ,ZHANG Bai-liang 3 (1.Life Science College,Henan Agricultural University,Zhengzhou 450002,China;2. Key Laboratory of Rural Renewable Energy,Ministry of Agriculture,Zhengzhou 450002,China;3.Mechanical &Electrical Engineering College,Henan Agricultural University,Zhengzhou 450002,China)The effect of pretreatment on enzymatic saccharification of maize straw by several chemical substances were studied.The result showed the optimum conditions as follows:the maize straw powder of 40 mesh was pretreated in 0.5% HCl at 121℃ for 60 min,and then was saccarified for 48 h at 50℃ in the buffer solution of acetic acid-sodium acetate of pH 4.8, with the ratio of liquid to solid 10,appending cellulase 2.5 g·(100 g) -1 and xylanase 2 mL·(100 g) -1 .As a result,the gross saccharification rate reached 48.5% and the transformation rate of cellulose and hemicellulose reached 80.8%.
Study on Antibacterial Mechanism of Flavonoids from Purslane
CHEN Guo-ni;SUN Fei-long;YAN Ya-ru;LIU Meng-meng;The antibacterial efficiency of flavonoids from purslane against Escherichia coli,Staphylococcus aureus and Saccharomycetes were measured by filter-paper method.The changes of reducing sugar content,soluble protein content,conductivity in the bacteria solution were detected.The antibacterial mechanism of flavonoids from purslane was analyzed.Results showed that the antibacterial purpose of flavonoids from purslane was achieved by disrupting cell membrane and leaking cellular content.
Application of MIEX-DOC~ Ion Exchange Resin in Arsenic Removal from Drinking Water
WANG Ming-tao,LI Teng,ZHU Chi,ZHAO Liang-yuan,JIANG Jin-hui,YANG Shao(Hubei Key Laboratory of City Water Environment,College of Life Science, Huazhong Normal University,Wuhan 430079,China)The performance of MIEX-DOC ion exchange resin in the arsenic removal from drinking water was investigated,including the removal capacity for arsenic,the removal capability for As(Ⅲ) and As(Ⅴ),and the effects of different ions and pH values on removal capabilities for As(Ⅲ) and As(Ⅴ).The result showed that MIEX-DOC resin′s removal capacity for arsenic was about 0.0051 mg·mL-1,and its capabilities of removing As(Ⅲ) and As(Ⅴ) showed no significance(P>0.05).Different ions showed significantly negative or positive effect on the arsenic removal of MIEX-DOC resin.pH Value also could greatly affect the arsenic removal,especially for As(Ⅲ),however,the arsenic removal was kept above 50% at the initial concentration of 0.1 mg·L-1.The field experiment showed that,by application of MIEX-DOC resin under the concentration condition of around 10 mg·L-1,the arsenic concentration decreased to below 0.05 mg·L-1,which reached the 《Drinking Water Health Standards》(GB 5749-2006) on the rural small-scale centralized water supply and decentralized water supply.The localized equipment using MIEX-DOC resin was the same as the imported equipment in effeciency of arsenic removal,but cheaper in the cost.The running cost was 0.56 Yuan per ton water for the localized equipment.In consequence,MIEX-DOC resin has a significant potential in arsenic removal and can be applied to the China′s countryside areas suffered from the high-arsenic drinking water.
Laboratory Studies of Chemical Mechanisms on the CO2 Oil-displacing
LI Meng-tao , ZHANG Hao, LIU Xian-gui ,SHANG Gen-hua ( Institute of Porous Flow & Fluid Mechanics of Chinese Academy of Sciences ,Langfang 065007 ,China; Engineering Service Center of Drilling Department of Huabei Oil Field ,Renqiu 061000,China)There are a series of experiment researches about CO2 oil displacing in the microcosmic and long cores test, component change of carbon in oil from tubule experiment. Based on these tests, some important chemical mechanisms on the craft mode of CO2 flooding and the water alternate gas injection are recognized. These mechanisms, including the effect of water on CO2 miscible flooding and miscible after extraction light C composition, offer good reference to studies of CO, flooding in oil reservoir and laboratory.
Research and Development Situation and Prospect of Water Retention Agents
XIE Xiu-ying,WAN Fang,ZHANG Yan,ZHU Shuang,XIONG Yan,CHEN Gui(School of Chemical and Environmental Engineering,Yangtze University,Jingzhou 434023,China)A systematically classification of known water retention agents was carried out by source of raw material classification method in this paper,and the advantages and disadvantages of all kinds of water retention agent were compared,the mechanism of water absorption was elaborated.Combined with the application of water retention agent,performance evaluation indexes,common synthetic methods and the concrete application of water retention agent were summarized.Finally,the developments of water retention agent were prospected on comprehensive of its current status of research and application.