Zinc removal from hyperaccumulator Sedum alfredii Hance biomass  

作　　者：杨建广 彭长宏 唐朝波 唐谟堂 周科朝 

机构地区：[1]School of Metallurgical Science and Engineering,Central South University [2]State Key Laboratory of Powder Metallurgy,Central South University

出　　处：《中国有色金属学会会刊：英文版》2009年第5期1353-1359,共7页Transactions of Nonferrous Metals Society of China

基　　金：Project(KY20080577000002)supported by the Hi-tech Research and Development Program of China;Project(20080431028)supported by China Postdoctoral Science Foundation;Project(50804056)supported by the National Natural Science Foundation of China

摘　　要：Leaching of heavy metals from Sedum alfredii Hance biomass was studied with ammonia-ammonium chloride solution as leaching agent.The research was carried out in two phases:1)a leaching study to determine the zinc extraction efficiency of this leaching agent,and 2)a thermodynamic analysis to identify the likely reactions and stable Zn(Ⅱ)species formed in the leaching systems.Taguchi orthogonal experiment,with four variable parameters,leaching temperature,molar ratio of NH4Cl to NH3,leaching time and solid-to-liquid(L/S)ratio,and each at three levels,was used to optimize the experiment parameters by the analysis of variances.The results indicate that leaching temperature has the most dominant effect on metal extraction performance,followed by molar ratio of NH4Cl to NH3,solid-to-liquid ratio and leaching time.The optimum condition was obtained as follows:temperature of 60℃,molecular ratio of NH4Cl to NH3 of 0.6,leaching time of 2 h and solid-to-liquid ratio of 5-1.The total zinc leaching efficiency under optimum conditions reaches 97.95%.The thermodynamic study indicates that the dominant species produced by the leaching process should be the soluble Zn(NH3)4 2+.Leaching of heavy metals from Sedum alfredii Hance biomass was studied with ammonia-ammonium chloride solution as leaching agent. The research was carried out in two phases： 1） a leaching study to ＂determine the zinc extraction efficiency of this leaching agent, and 2） a thermodynamic analysis to identify the likely reactions and stable Zn（Ⅱ） species formed in the leaching systems. Taguchi orthogonal experiment, with four variable parameters, leaching temperature, molar ratio of NH4Cl to NH3, leaching time and solid-to-liquid（L/S） ratio, and each at three levels, was used to optimize the experiment parameters by the analysis of variances. The results indicate that leaching temperature has the most dominant effect on metal extraction performance, followed by molar ratio of NH4Cl to NH3, solid-to-liquid ratio and leaching time. The optimum condition was obtained as follows： temperature of 60℃, molecular ratio of NH4Cl to NH3 of 0.6, leaching time of 2 h and solid-to-liquid ratio of 5：1. The total zinc leaching efficiency under optimum conditions reaches 97.95%. The thermodynamic study indicates that the dominant species produced by the leaching process should be the soluble Zn（NH3）4^2＋.

关 键 词：东南景天 超积累植物 去除量 锌 热力学分析 浸出温度 浸出时间 最佳条件 

分 类 号：X703[环境科学与工程—环境工程]