铬在土壤及其组分中的吸附行为

运用火焰原子吸收法跟踪,对三价铬离子在暗棕壤及其组分中的吸附行为进行研究,表明8 h暗棕壤对铬的吸附可达平衡。选择Freundlich方程对吸附实验的数据进行拟合,可见暗棕壤、胡敏酸、矿物质三者之间对铬的吸附量的关系为胡敏酸>暗棕壤>矿物质,在实验条件下胡敏酸对铬的吸附属于线性分配吸附,其余属于非线性分配吸附。研究了pH值对暗棕壤吸附铬的影响。pH值小于7.0时,暗棕壤对铬的吸附量随着pH值的增大而增加;pH值大于7.0时,三价铬离子完全以氢氧化物的形式沉淀于吸附质上,故此条件下暗棕壤对铬的吸附量不受pH值的影响。

Adsorption Behavior of Soil and its Composing Component to Chromium

This paper studied the adsorption behavior of trivalent chromium to dark brown forest soil and its composing component by means of flame atomic absorption spectrophotometer.The result showed that the absorption of chromium by dark brown forest soil could reach the balance for as long as eight hours.The adsorption experiment data is fit with Freundlich equation,the order of adsorption to chromium is humic acid>dark brown forest soil>minerals.Under experimental conditions,it's linear distribution adsorption for humic acid to chromium,the others are nonlinear partition adsorption.Mearnwhile,the effect of pH value to the adsorption of chromium by dark brown forest soil is also investigated.When pH value is below 7.0,the adsorption is increased with increasing pH value,however,when pH value is above 7.0,the trivalent chromium is precipitaed into the adsorptive materials in the form of hydroxide.So the adsorption isn't affected by pH value under such circumstances.