Cu(Ⅱ)对红壤性水稻土吸附Cr(Ⅵ)的影响  

Effect of Cu(Ⅱ) on Adsorption of Cr(Ⅵ) by Paddy Soil Derived from Red Earth

作　　者：肖双成[1] 徐仁扣[1] 

机构地区：[1]中国科学院南京土壤研究所土壤与农业可持续发展国家重点实验室,江苏南京210008

出　　处：《农业环境科学学报》2007年第1期262-264,共3页Journal of Agro-Environment Science

基　　金：国家重点基础规划项目(2002CB410808);国家自然科学基金项目(20577054)

摘　　要：选择一种红壤性水稻土研究了Cu(Ⅱ)对土壤吸附CrO24-的影响。结果表明,Cu(Ⅱ)显著增加了土壤对CrO24-的吸附量,Cu(Ⅱ)对CrO24-吸附的影响程度随着Cu(Ⅱ)加入量的增加和体系pH的升高而增加。Cu(Ⅱ)不仅增加土壤对CrO24-的吸附量,也增加CrO24-的解吸量,但解吸增量比吸附增量低得多,说明Cu(Ⅱ)对CrO42-在土壤中吸附的促进作用机制涉及静电作用、专性吸附和表面共沉淀。铜的促进作用增加了土壤对CrO24-的固定量,降低了CrO24-的活动性和生物有效性。A paddy soil derived from red earth was chosen to study the effect of Cu（ Ⅱ ） on CrO4^2- adsorption by the soil. Results showed that the presence of Cu（ Ⅱ ） led to the increase in CrO4^2- adsorption, and the influencing degree of Cu（ Ⅱ ） increased with the increase in the amount of Cu（Ⅱ ） added and the rise of pH. Cu（ Ⅱ ） increased not only the adsorption of CrO4^2-, but also the desorption of pre-adsorbed CrO4^2-. Howev er, the increment of CrO4^2- desorption was lower than that of CrO4^2- adsorption, suggesting that the enhancement mechanisms of Cu（Ⅱ） on CrO4^2- adsorption on the soil involved the electrostatic attraction, specific adsorption and the formation of surface co-precipitates. The specific adsorption of Cu（ Ⅱ ） on the soil increased the positive surface charge and surface potential and thus resulted in the increase in CrO4^2-CrO4^2- adsorption through electrostatic attraction. The effect of Cu（ Ⅱ ） on surface potential also increased with the rise of pH, which is one of the reasons for the increase of Cu（ Ⅱ ） enhancement with pH rising. The enhancement of Cu（ Ⅱ ） increased the amount of CrO4^2- fixed by soil and reduced its mobility in soil and availability to plants.

关 键 词：水稻土 Cu(Ⅱ) CrO4^2- 吸附 解吸 

分 类 号：X503.231[环境科学与工程—环境工程]