滨海平原水库底质对铬的吸附作用

Adsorption of Chromium at the Bottom Sediment of Coastal Plain Reservoir

以天津滨海地区北大港水库底质为研究对象,采用室内土柱试验,研究库底不同位置底质对铬的吸附动态变化特征,同时探讨了底质对铬的吸附机理。研究结果表明:水库不同位置的底质对铬的吸附能力不同,入库口处底质对水库中铬的吸附作用很容易达到饱和,达到饱和后,底质中残留的铬会释放到水体中;而水库出水口与库中心位置对铬吸附能力很强,很难达到饱和,从而有效地降低水体中铬的含量。底质对铬的累积吸附量与孔隙体积数的变化曲线符合直线型方程;底质对重金属铬的吸附作用与底质固体颗粒粒径大小、阳离子交换量和含盐量等因素有关。

The sediments in different locations of the bottom of the Beidagang reservoir in the coastal area of Tianjin City were collected and performed laboratory soil-column experiments to investigate the dynamic characteristics of chromium adsorption occurring at these sediments,which can help understand the adsorption mechanisms of chromium at the sediments.The results showed that the abilities to absorb chromium of the sediments vary with different positions of the reservoir bottom.The adsorption capacity of chromium was easy to reach the saturation status for the sediments at the entrance of the reservoir,and the residual chromium in the sediments can be released to the water after the adsorption saturation.The chromium adsorption capacity was strong and not easy to reach the saturation status for the sediments at the outlet and center of the reservoir,which therefore can decrease the content of chromium in the water.The accumulative quantity of chromium adsorption at the bottom sediments were in a linear relationship with the pore volumes.Furthermore,the adsorption capacity of chromium at the bottom sediments was related to the particle size,cation exchange capacity,and salinity of the sediments.