土壤有机质对镉在土壤中吸附-解吸行为的影响  

EFFECTS OF ORGANIC MATTER ON CADMIUM ADSORPTION-DESORPTION IN THREE SOILS

作　　者：焦文涛[1] 蒋新[1] 余贵芬[1] 王代长[1] 卞永荣[1] 邓建才[1] 

机构地区：[1]中国科学院南京土壤研究所,南京210008

出　　处：《环境化学》2005年第5期545-549,共5页Environmental Chemistry

基　　金：国家自然科学基金(40201025;40325001);江苏省自然科学基金重点项目(BK2005220);中国科学院知识创新前沿项目(No.ISSASIP0202);国际科学基金项目(IFSC/3403-1)资助

摘　　要：研究了Cd2+在红壤、黄泥土、乌栅土及去除有机质后的三种土壤中的吸附-解吸行为.结果表明,有机质的去除显著降低了三种土壤体系Cd2+吸附-解吸平衡液的pH值,ΔpH范围为0·51到3·05.三种土壤中Cd2+的吸附量大小为:乌栅土>黄泥土>>红壤,与土壤有机质含量的顺序一致;去除有机质后土壤对Cd2+的吸附量均明显下降,尤其是有机质含量高的黄泥土和乌栅土;三种土壤有机质对Cd2+吸附的贡献率平均值分别为红壤43·75%、黄泥土544·77%、乌栅土993·76%.Cd2+在所有土壤中的吸附均可用Freun-dlich方程来描述,相关系数均大于0·991,吸附亲和力的变化与吸附量大小的变化一致,n值在0·350到0·975之间变化.三种土壤中Cd2+解吸量依次减少,红壤中Cd2+解吸率均在50%以上,而黄泥土和乌栅土中解吸率最高为42%和19%;去除有机质后解吸率均在50%以上,且解吸量相差不大.The adsorption-desorption behaviors of Cd^2＋ in red soil, Huangni soil and Wushan soil were studied in present study. The results showed that the pH values of adsorption-desorption equilibrium system in three soils decreased significantly as soil organic matter （SOM） was removed. The decrease of pH values ranged from 0. 5 to 3.05. With the content of SOM increasing, amount of Cd^2＋ adsorbed increased. The amount of Cd^2＋ adsorbed reduced drastically after SOM was removed, especially for Huangni soil and Wushan soils with high contents of SOM. The contribution rate of SOM to the adsorption of Cd^2＋ were 43.75%, 544. 77%, 993.76% in Red soil, Huangni soil and Wushan soil, respectively. All processes of Cd^2＋ adsorption in soils could be described by Freundlich isotherms with the correlation coefficient higher than 0. 991. The variation of Cd affi nity for three soils explained well the variationof amount of Cd^2＋ adsorbed and n values ranged from 0. 350 to 0. 975. The desorption amount of Cd^2＋ in red soil, Huangni soil and Wushan soil decreased in turn. The desorption rate of Cd^2＋ in Red soil was 〉 50% , whereas the maximum desorption rate of Cd^2＋ were 42% and 19% in Huangni soil and Wushan soil, respectively. The desorption rate was 〉 50% after SOM was removed and the desorption amount of Cd^2＋ didn＇t vary significantly.

关 键 词：镉 土壤有机质 吸附-解吸 土壤有机质含量 解吸行为 Cd^2+吸附 FREUNDLICH方程 黄泥土 吸附量 解吸率 Ph范围 

分 类 号：X53[环境科学与工程—环境工程]