镉在腐植酸上的吸附与解吸特征研究  

Characteristics of Adsorption and Desorption of Cadmium on Humic Acids

作　　者：李光林[1] 魏世强[2] 青长乐[2] 牟树森[2] 

机构地区：[1]西南农业大学基础科技学院,重庆400716 [2]西南农业大学资源环境学院,重庆400716

出　　处：《农业环境科学学报》2003年第1期34-37,共4页Journal of Agro-Environment Science

基　　金：~~

摘　　要：采用镉离子选择电极研究了镉在腐植酸两组分(富里酸FA、胡敏酸HA)上的吸附-解吸量和动力学特性以及介质pH的影响。结果表明,腐植酸对镉的吸附容量以FA>HA,吸附强度以HA>FA,而解吸量以FA-Cd>HA-Cd。腐植酸与镉的吸附动力学用Evolich方程描述最佳。FA对镉的吸附速度和解吸速度高于HA。当4.0<pH<6.5,用Langmuir等温吸附式描述最佳,当3.0<pH<4.0时,用Freundilich等温吸附式描述最佳。当pH在6.5以下,介质pH升高利于镉的吸附,且难以解吸。Amount and kinetics characteristic s of cadmium adsorption and desorpti on on two humic acids(FA and HA)and the effect of pH were studied by the technique of cadmium ion choosing electrode.The results showed that the adsorption c apactity of cadmium on FA is larger than on HA and adsorption strength of HA is larger than of FA,and desorption amount is FA -Cd larger than HA -Cd,adsorption and desorption kinetics of cadmium on humic acids fitted with Evolich Equations the best.The s peed of cadmium adsorption on and desorption from FA is highter than that of HA.Under the c omdition of 4.0<pH <6.5,Langmuir is otherm ad-sorption fitted best,while under th e condition of 3.0<pH <4.0,Freundlich isotherm adsorptoin fitted best,and under the condition of pH <6.5,humic acids are able to adsorb more cadmium with higher speed as medium pH increases and the adsorbed cadmium is more difficult to desorb.

关 键 词：解吸特征 腐植酸 镉 吸附特征 生物有效性 

分 类 号：X13[环境科学与工程—环境科学]