河湖沉积物中酸挥发性硫化物对重金属吸附及释放的影响

Influence of acid-volatile sulfides on adsorption and release of heavy metals in lake and river sediments

通过吸附、释放实验研究了河流及湖泊沉积物酸挥发性硫化物对上覆水中重金属元素的影响 .采用兼具Langmuir及Freundlish等温线方程两种方程特征的Sips表达式及无机离子分级交换理论 ,较好地对重金属元素在沉积物或颗粒物上的吸附及释放特征进行了描述 .结果表明 ,存在于水溶液中的重金属可以不断地与沉积物结合 ,从而使水溶液中的重金属浓度维持在一很低的水平上 ;并且 ,一旦与沉积物结合 ,重金属就很难再释放出来 .酸挥发性硫化物的存在增加了沉积物的吸附容量 ,但酸挥发性硫化物经过酸化被除去后 ,沉积物中的与之结合重金属元素就会释放出来 。

The influence of acid volatile sulfides in sediments on heavy metals in overlying water was studied through adsorption and release experiments. Sips isotherm equation was used to describe heavy metals adsorbed onto sediments, and grade ion exchange theory was used to describe the release process. The results showed that heavy metals in the overlying water were transferred to sediments incessantly, which made the concentration of heavy metals in the overlying water in a low level. Heavy metals in sediments would hardly be released if they were bound by sediments, but would be released if the acid volatile sulfides in sediments were removed. The acid volatile sulfide plays a major role in controlling metals activity.