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Advances in Chemical Engineering and Science 2013年第3期3卷 171-177页

作者： Alejandro Valenzuela Jesús L. Valenzuela José R. Parga Department of Chemical Engineering and Metallurgy University of Sonora Hermosillo México

The majority of the refractory gold and silver occurs in occlusion in sulphides, then precious metal dissolution is possible by first oxidizing auriferous sulfide concentrate using sodium hypochlorite-sodium-hydroxide solution followed of pressure cyanidation of the oxidized concentrate, for the extraction of precious metals. This process was conducted and evaluated under cyanide and oxygen pressure. This versatile approach offers many advantages, including low temperatures, low pressure and less costly materials of construction than conventional pressure oxidation. In this study, the effect of oxygen pressure, concentration of sodium hypochlorite, temperature, and initial pH, in precious metals recovery and As removal were evaluated using a 24 factorial design. Characterization of the ores showed that pyrite and arsenopyrite were the main minerals present on the concentrate. The best results for gold extraction were obtained with oxygen pressure of 80 psi, 10% (w/w) sodium hypochlorite, temperature of 80℃, at pH = 13, and a constant stirring speed of 600 rpm. These conditions allowed an approximated 60% of gold and 90% of silver extractions in 1 hr.

关键词： Refractory Gold Concentrate Hypochlorite Oxidation pretreatment Pressure Cyanidation

Studies on the effects of pretreatment on production hydrogen from municipal sludge anaerobic fermentation

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Natural Science 2009年第1期1卷 10-16页

作者： Feng Wu Shao-Qi Zhou Yang-Lan Lai Wen-Jiao Zhong 1. College of Environmental Science and Engineering South China University of Technology Guangzhou 510006 China 2. Guangdong Provincial People’s Armed School Guangzhou 510006 China. College of Environmental Science and Engineering South China University of Technology Guangzhou 510006 China Guangdong Provincial People’s Armed School Guangzhou 510006 China.

Municipal sludge was rich in organic matter, period of natural degradation was long and low efficiency, leachate would pollute underground water. In this paper, a comparative study of the ways of pretreatment with acid alkali treatment, heat digestion and ultrasonic treatment were done. The results showed that The dehydro-genase activity were increased, the SCOD (soluable chemical oxygen demand, SCOD) in-creased more than 2.47~2.83, 1.70~1.76, 2.6~ 2.77 times respectively. The hydrogen yield in-creased more than 11.5~12.2, 24.1~24.7, 34.2~ 34.9 mL.g-1 (VS) respectively. The period of pro- hydrogen was shorten to 7.5, 8.0, 6.5 d respec-tively. The degradation rate was up to 72.04%, 81.4%, 80% respectively, the methane concen-tration in the gas was close to “zero” and ul-trasonic treatment was better than others. Gompertz model curve fitting on hydrogen production was carried out. All the values of correlation factor R2 were more than 0.97.

关键词： Municipal Sludge pretreatment Anaerobic Digestion Biological Pro-Hydrogen

Comparison of two pretreatment methods for mercury stable isotope analysis in Antarctic moss

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Advances in Polar Science 2017年第1期28卷 75-80页

作者： LIU Hongwei YU Ben SHI Jianbo ZHANG Qinghua JIANG Guibin State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of Sciences College of Resources and Environment University of Chinese Academy of Sciences

Mercury （Hg） stable isotope analysis can provide new insight for understanding the biogeochemistry and sources of Hg in the polar regions. To completely extract the low contents of Hg in polar samples and to avoid isotopic fractionation during the sample preparation stage, an effective and reliable pretreatment method is needed. In this work, two different pretreatment methods were compared for measuring Hg stable isotopes in Antarctic moss samples. One method was acid digestion （HNO3 ： H2O2=5 ： 3, v/v） and the second was a combustion-trapping treatment with a trapping solution （HNO3：HCl=2：1, v/v）. There were no significant differences in the analytical results obtained with the two methods. The overall mean values and uncertainties of total Hg （THg） and the isotopic compositions of Hg in the referenced materials were all in good agreement with the certified and reported values, indicating that both methods were accurate and applicable. Acid digestion is highly efficient, while the combustion-trapping method can be used to treat samples with low Hg content. The proposed methods were successfully used to determine the Hg isotopic compositions in moss samples collected from the Antarctic.

关键词： mercury stable isotope pretreatment acid digestion combustion-trapping treatment

Application of Box-Behnken Design for Optimization of Different pretreatment Conditions for Cellulase Production

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Journal of Northeast Agricultural University(English Edition) 2017年第3期24卷 51-59页

作者： Sidra Iqbal Muhammad Irfan Fouzia Tabassum Hafiz Abdullah Shakir Javed Iqbal Qazi Microbial Biotechnology Laboratory Department of ZoologyUniversity of the PunjabNew Campus Lahore 54590Pakistan Department of Biotechnology University of SargodhaSargodha 54590Pakistan

Effects of dilute acid and acid steam pretreatments were inspected for cellulose production of Eucalyptus leaves through Box-Behenken design, a three variable factors for response surface methodology by Bacillus subtilus K-18. Maximum cellulose production performed in 250 mL erlenmeyer flask with submerged fermentation attained at 50＂C, pH 5, 140 r· min-1 for 24 h. Results showed the efficient cellulose production from acid steam pretreatrnent （being autoclaved at 15 Psi for 15 rain） than acid pretreatment. The optimum condition for maximum carboxymethyl cellulas （CMCase） was 1.811 IU·mL-1·min-1 （0.8% acid cone., 10 g biomass loading, 6 h reaction time） and filter paper activity （FPase） was 2.255 IU·mL·-1·min-1 （1% acid conc., 10 g biomass loading, 8 h reaction time）. Whereas, the acid steam maximum CMCase activity recorded was 2.585 IU·mL-1·min-1 （0.8% acid cone., 15 g substrate loading and 8 h reaction time） and the highest FPase activity was 2.055 IU·mL-1·min-1 （0.8% cone., 10 g biomass, 6 h reaction time then autoclaved）. Results revealed that acid pretreated Eucalyptus leaves were better lignocellulosic biomass for cellulose production by submerged fermentation.

关键词： cellulase pretreatment Eucalyptus Bacillus sp. Response Surface Methodology (RSM)

The Influence of Abrasive pretreatment on Hot Air Drying of Grape

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Food and Nutrition Sciences 2015年第3期6卷 355-364页

作者： Giuseppina Adiletta Wijitha Senadeera Loredana Liguori Alessio Crescitelli Donatella Albanese Paola Russo Department of Industrial Engineering University of Salerno Fisciano Italy School of Chemistry Physics and Mechanical Engineering Faculty of Science and Engineering Queensland University of Technology Brisbane Australia Institute for Microelectronics and Microsystems Napoli Italy Department of Chemical Engineering Materials Environment University of Rome “La Sapienza” Roma Italy

The drying of grapes is a more complex process compared to the dehydration of other agricultural materials due to the necessity of a pretreatment operation prior to drying. Grape drying to produce raisins is a very slow process, due to the peculiar structure of grape peel, that is covered by a waxy layer. Its removal has been so far carried out by using several chemical pre-treatments. However, they cause heterogeneity in the waxes removal and create microscopic cracks. In this paper an abrasive pretreatment for enhancing the drying rate and preserving the grape samples is proposed. Two cultivars of grape were investigated: Regina white grape and Red Globe red grape. The drying kinetics of untreated and treated samples were studied using a convective oven at 50°C. Fruit quality parameters such as sugar and organic acid contents, shrinkage, texture, peel damage (i.e. by SEM analysis) and rehydration capacity were studied to evaluate the effectiveness of abrasive pretreatment on raisins. Abrasive pretreatment contributed to reduce drying time and rehydration time. The treated and untreated dried grapes were significantly different (p < 0.05) in sugar and in tartaric acid content. On the contrary, no significant differences (p < 0.05) in malic and citric acids and in texture properties between untreated and treated samples were observed.

关键词： Grape Drying Raisin Abrasive pretreatment Sugar Content Shrinkage Texture Rehydration

Effects of Chemical pretreatment on Enzymatic Saccharification and Fermentation of Forages

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Animal Husbandry and Feed Science 2009年第3期1卷 19-23页

作者：高凤芹孙启忠中国农业科学院草原研究所内蒙古呼和浩特010010 农业部草原资源与生态重点开放实验室内蒙古呼和浩特010010

[ Objective] To study the effect of pretreatment with chemical substances on enzymatic saccharification of affalfa （ Medic, ago sativa L. ）, sorghum hybrid sudan grass [ Sorghum bicolor （ L. ） Moench x Sorghum sudanese （Piper） Stapf], erect milkvetch （Astraga/us adsurgens Pall. ） and pearl millet （ Pennisetum americanum （ L. ） Leeke）. [ Method ] The forages were pretreated with sulfuric acid at different concentration, and then the content of cellulose, hemicellulose, and lignin were detected and compared with that before pretreatment. The concentration of glucose and ethanol after different fermentation time was also determined. [ Result] After pretreatment, the content of cellulose increased, while that of hemicel- lulose and lignin decreased. After treatment with 1.0% （W/V） sulfuric acid, the four kinds of forages all had the highest concentration of ethanol in the citric acid-sodium citrate buffer system （pH 4.8）. Dudng fermentation process, the concentration of glucose and ethanol first increased and then declined, peaking respectively at 24 h and 48 h post fermentation. [Condusion] pretreatment promotes the enzymatic saccharification and fermen- tation of alfalfa, sorehum hvbrid sudan orass. Dead millet, and erect milkvetch, and their enerov performance decreases in order.

关键词： pretreatment Forage Cellulose ethanol Enzymatic saccharification and fermentation

Influence of acupuncture and moxibustion pretreatment at“Neiguan”( PC 6) on Connexin 43 in myocardial cell in rabbits of myocardial ischemia reperfusion

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China Medical Abstracts(Internal Medicine) 2014年第1期31卷 5-6页

作者：周丹 8th Hosp Changsha

Objective To observe change of expression level of Connexin 43(Cx 43)in myocardial mitochondria of ischemia reperfusion injury after pretreatment of acupuncture and moxibustion at"Neiguan"(PC 6)in rabbits,and compare the different effect between electroacupuncture and *** Thirty-two New Zealand big-eared white rabbits were randomly divided into a model group,an electroacupuncture group,a moxibustion group and a sham-operation group,8 cases in each *** model

关键词： moxibustion Neiguan PC 6 acupuncture Connexin pretreatment mitochondria eared Zealand statistically

The Impact on Extraction Effect of Polysaccharide from Ganoderma lucidum by Different pretreatment

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Medicinal Plant 2018年第3期9卷 14-16,20页

作者： Jinyi LIANG Jinghao ZHOU Jianping ZHOU Yifeng TAN Keyong XU Kaiping Healthwise Health Food Co.Ltd.

[Objectives] The research aimed to study the impact on extraction effect of polysaccharide from Ganoderma lucidum( lingzhi) by different pretreatment methods. [Methods] The impacts on extraction of G. lucidum polysaccharide by soaking,microwave and air flow fine pulverization were contrasted,and the extraction effect of G. lucidum polysaccharide by combining the optimal pretreatment manner with hot water extraction,alcohol extraction,alkali extraction,ultrasonic binding enzyme extraction,and microwave extraction was compared. Finally,the property of G. lucidum polysaccharide obtained after air flow fine pulverization pretreatment was detected and analyzed by high performance liquid chromatography. [Results] The optimal pretreatment method was air flow fine pulverization. Compared with traditional method-direct extraction( coarse grinding combining hot water extraction),crude yield changed little,while polysaccharide content and yield were improved by 114% and 104%. The best combination manner was air flow fine pulverization pretreatment combining with alkali extraction. Compared with traditional method,crude yield,polysaccharide content and yield were improved by 76%,78% and 215% respectively. The property of G. lucidum polysaccharide obtained after air flow fine pulverization pretreatment was detected and analyzed by high performance liquid chromatography. It was found that the treatment method had little impact on the property of G. lucidum polysaccharide. [Conclusions]Air flow fine pulverization pretreatment could greatly improve extraction effect of G. lucidum polysaccharide,which mainly improved the content and yield of G. lucidum polysaccharide,and extraction was more complete,with less impact on the property of the extracted polysaccharide. It was speculated that air flow fine pulverization pretreatment mainly destroyed mechanical support wall membrane structure of G. lucidum fine powder,making that intracellular functional substances completely dissolved out

关键词： pretreatment Air flow fine pulverization Ganoderma lucidum polysaccharide Extraction effect Polysaccharide property

Effective of Microwave-KOH pretreatment on Enzymatic Hydrolysis of Bamboo

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Journal of Sustainable Bioenergy Systems 2012年第4期2卷 104-107页

作者： Zhiqiang Li Zehui Jiang Benhua Fei Yan Yu Zhiyong Cai Forest Products Laboratory USDA Forest Service Madison USA International Centre for Bamboo and Rattan Beijing China

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.

关键词： Bamboo Microwave-KOH pretreatment Chemical pretreatment Enzymatic Hydrolysis BioethanolProduction

Effects of pretreatment with recombinant human B-type natriuretic peptide on infarct size in patients with acute ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention

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China Medical Abstracts(Internal Medicine) 2016年第1期33卷 26-27页

作者：李世强 Cardiol Dept 2nd HospHebei Med Univ

Objective To investigate whether the administration of recombinant human B-type natriuretic peptide(rh BNP)before primary percutaneous coronary intervention(PCI)could further limit the infract size,improve left ventri... 详细信息

关键词： natriuretic elevation pretreatment infarct administration dilation alleviate remodeling perfusion corrected