水溶性有机质对镉在土壤中吸附行为的影响

Cadmium Adsorption in Soil Influenced by Dissolved Organic Matters Derived from Pig Manure and Rice Straw

水溶性有机质(DOM)是环境中最为活跃的化学组成之一,无疑会对土壤中重金属的迁移转化具有很大的影响。通过等温吸附试验和动力学试验,研究了由猪粪和稻草提取的DOM对重庆市菜地典型土壤中Cd吸附行为的影响。结果表明:Cd在土壤中的吸附行为由于土壤类型和添加的DOM种类的不同而有所差异,在紫色土中,稻草DOM对Cd的吸附表现出明显的抑制作用,而猪粪DOM在低浓度时对Cd的吸附有抑制作用,但在较高浓度时,猪粪DOM反而表现出对Cd的促进吸附;在黄壤中,稻草DOM也有使Cd的吸附减少的趋势,而猪粪DOM对Cd的吸附有强烈的促进作用。

DOM is one of the most active chemical components in environment. It has great influence on transport and transformation of heavy metals in soil. An investigation on the effects of different DOMs, which were extracted from pig manure （DOMpm） and rice straw （DOMrs）, respectively, on adsorption of Cd in the typical vegetable garden soils in Chongqing were carried out using isothermal adsorption and kinetic experiment. The results of experiment showed that the adsorption behavior of Cd was different in different soil and application DOM. In purple soil, DOMrs reduced the Cd adsorption obviously while DOMpm reduced the Cd adsorption in lower concentration but enhanced in higher one. In yellow soil, DOMrs also reduced the Cd adsorption. However, DOMpm can obviously enhance Cd adsorption by soil.