溶液离子强度对自然水体生物膜吸附Pb^(2+)和Cd^(2+)的影响  

Effect of ionic strength in solution on Pb^(2+) and Cd^(2+) adsorption to surface coatings

作　　者：张波涛[1] 董德明[1] 杨帆[1] 李鱼[1] 吴雨华[1] 

机构地区：[1]吉林大学环境与资源学院,吉林长春130023

出　　处：《吉林大学学报（地球科学版）》2004年第4期566-570,共5页Journal of Jilin University：Earth Science Edition

基　　金：教育部高等学校博士学科点专项科研基金资助(20020183056)

摘　　要：通过改变支持电解质(NaNO3)浓度的方法来探讨自然水体生物膜对Pb2+、Cd2+的吸附机制,研究了离子强度对生物膜吸附Pb2+、Cd2+的影响以及不同离子强度下生物膜吸附Pb2+、Cd2+的热力学特征。结果表明:当NaNO3浓度在0～0.4mol·L-1之间,随着离子强度的增加,生物膜对Pb2+和Cd2+的吸附量和最大吸附量迅速降低;当NaNO3的浓度大于0.4mol·L-1,生物膜对Pb2+和Cd2+的吸附量和最大吸附量变化趋于平缓,说明自然水体生物膜对Pb2+和Cd2+的吸附可能同时包括电性吸附和专性吸附。此外,研究还发现当Cd2+与Pb2+共存时,Pb2+对生物膜吸附Cd2+的能力有较大影响,而Cd2+对生物膜吸附Pb2+的能力的影响并不显著。The effect of ionic strength on Pb^(2+) and Cd^(2+) adsorption to surface coatings was investigated. The results showed that the amount of Pb^(2+) and Cd^(2+) adsorption to surface coatings dropped dramatically with the increase of concentration of NaNO_3 as supporting electrolyte (0～0.4 mol·L^(-1)), but when the concentration of NaNO_3 was above 0.4 mol·L^(-1), the amount of adsorption kept relatively steady. The maximum adsorption amount of Pb^(2+) and Cd^(2+) analyzed by Langmuir isotherm at different ionic strengths also showed the similar results. These proved the possible simultaneous existence of the electrostatic adsorption and specific adsorption. It was found that the amount of Cd^(2+) adsorption to surface coatings was affected by Pb^(2+) significantly, while the influence of Cd^(2+) on Pb^(2+) was almost negligible when Pb^(2+) and Cd^(2+) coexisted.

关 键 词：生物膜 离子强度 铅离子 镉离子 吸附 

分 类 号：X132[环境科学与工程—环境科学]