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991.
In this study, the surface chemical functional groups of Bacillus cereus biomass were identified by Fourier transform infrared (FTIR) analytical technique. It had been shown that the B. cereus cells mainly contained carboxyl, hydroxyl, phosphate, amino and amide functional groups. The potentiometric titration was conducted to explain the surface acid-base properties of aqueous B. cereus biomass. The computer program FITEQL 4.0 was used to perform the model calculations. The optimization results indicated that three sitesthree pKas model, which assumed the cell surface to have three distinct types of surface organic functional groups based on the IR analysis results, simulated the experimental results very well. Moreover, batch adsorption experiments were performed to investigate biosorption behavior of Cu(Ⅱ) and Pb(Ⅱ) ions onto the biomass. Obviously, the adsorption equilibrium data for the two ions were reasonably described by typical Langmuir isotherm. 相似文献
992.
The electrochemical reduction characteristics of carbon tetrachloride (CT) were investigated using cyclic voltammetry in this study. In addition, the difference in reduction mechanisms of CT between Master Builders' iron and the catalyzed Fe-Cu process was discussed. The results showed that CT was reduced directly on the surface of copper rather than by atomic hydrogen produced at the cathode in the catalyzed Fe-Cu process. The reduction was realized largely by atomic hydrogen in Master Builders' iron. The entire CT in 350 ml aqueous solution with 320 mgL was reduced to trichloromethane and dichloromethane in 2.25 h when 100 g of scrap iron with FeCu ratio of 10:1 (ww) were used. Moreover, the reduction rate slowed with time. CT could be reduced at acidic, neutral and alkaline pH from solution by Fe-Cu bimetallic media, but the mechanisms were di?erent. The degradation rate was not significantly in?uenced by pH in the catalyzed Fe-Cu process; in Master Builders' iron it clearly increased with decreasing pH. The kinetics of the reductions followed pseudo-first order in both cases. Furthermore, the reductions under acidic conditions proceeded faster than that under the neutral and alkaline conditions. The catalyzed Fe-Cu process was superior to Master Builders' iron in treating CT-containing water and this advantage was particularly noticeable under alkaline conditions. The reduction was investigated in the cathode (Cu) and anode (Fe) compartments respectively, the results showed that the direct reduction pathway played an important role in the reduction by the catalyzed Fe-Cu process. The catalyzed Fe-Cu process is of practical value. 相似文献
993.
LIU Ting-feng SUN Cheng TA N HONG Jun YANG Shao-gui CHEN Chuan-xiang 《环境科学学报(英文版)》2007,19(10):1235-1238
The influence of coexisting copper (Cu) ion on the degradation of pesticides pyrethroid cypermethrin and cyhalothrin in soil and photodegradation in water system were studied.Serial concentrations of the pesticides with the addition of copper ion were spiked in the soil and incubated for a regular period of time,the analysis of the extracts from the soil was carried out using gas chromatography (GC).The photodegradation of pyrethroids in water system was conducted under UV irradiation.The effect of Cu~(2 ) on the pesticides degradation was measured with half life (t_(0.5)) of degradation.It was found that a negative correlation between the degradation of the pyrethroid pesticides in soil and Cu addition was observed.But Cu~(2 ) could accelerate photodegradation of the pyrethroids in water.The t_(0.5) for cyhalothrin extended from 6.7 to 6.8 d while for cypermethrin extended from 8.1 to 10.9 d with the presence of copper ion in soil.As for photodegradation,t_(0.5) for cyhalothrin reduced from 173.3 to 115.5 rain and for cypermethrin from 115.5 to 99.0 min.The results suggested that copper influenced the degradation of the pesticides in soil by affecting the activity of microorganisms.However, it had catalyst tendency for photodegradation in water system.The difference for the degradation efficiency of pyrethroid isomers in soil was also observed.Copper could obviously accelerate the degradation of some special isomers. 相似文献
994.
为了使大家更好地感受祖国举办的奥运会,华锡集团铜坑矿通过多种方法和手段,构筑起一道安全屏障,以实际行动喜迎奥运会的到来。 相似文献
995.
英驰 《再生资源与循环经济》2008,1(9):26-26
“一根扁担,两只箩筐。串乡走户,收旧拾荒。”这是当年汨罗“破烂王”谋生的真实写照。但如今。湖南省汨罗市的“拾荒佬”竟在废旧物资回收领域做得风生水起。日前,在湖南省的全省新型城市化工作会议上,汨罗市代市长周金龙不无自豪地说,以再生资源项目为主体、依托循环经济建起来的汨罗工业园2008年有望产值突破100亿元,成为真金实银的“百亿园区”。 相似文献
996.
997.
重金属Cu^2+对锦鲫和日本沼虾的急性毒性研究 总被引:2,自引:0,他引:2
研究了重金属Cu2 对锦鲫和日本沼虾的急性毒性,采用直线内插法求得Cu2 对锦鲫和日本沼虾24h、48h及96h的半数致死浓度LC50分别为20.168mg/L、15.500mg/L、10.250mg/L和0.845mg/L,mg/L、0.362mg/L.根据化学物质的毒性分级标准,Cu2 对锦鲫的毒性属于高毒,对日本沼虾属于剧毒.以浓度对数和死亡率进行回归分析,得出锦鲫24h、48h及96h的回归方程分别为:y=7.92ln(x)-4.94,r=0.853;y=16.26ln(x)-5.51,r=0.960;y=18.17ln(x) 10.01,r=0.965.日本沼虾24h、48h及96h的回归方程分别为:y=49.78ln(x) 55.13,r=0.971;y=80.4ln(x) 117.56,r=0.895;y=55.02ln(x) 115.17,r=0.735. 相似文献
998.
实验室常见废液处理方法介绍 总被引:1,自引:0,他引:1
讨论实验室废液的来源和对环境的危害性,并着重对实验室废液的分类、处理方法及注意事项进行探讨。 相似文献
999.
1000.
采用生物吸附法,研究了经过预处理的无花果曲霉对Cu^2 吸附行为与影响吸附的主要因素,具体包括菌丝球与Cu^2 接触反应时间、Cu^2 浓度、原初pH值3个方面。结果表明:该菌丝球在吸附进行5min时,吸附量已达量2.855mg/g,在吸附进行4h以后趋于平衡。最佳pH范围为4.0-5.0,Cu62 浓度在20-100mg/L范围内吸附量为2.763-4.713mg/g,而吸附率却为32.31%-9.54%。其吸附行为在一定的温度和一定浓度范围内较好地符合Langmuir吸附等温模型。 相似文献