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研究了黄河水中表层沉积物与镉液 -固界面相互作用的离子交换率E(% ) -pH曲线 ,以及河水中甘氨酸的存在对该曲线的影响 .实验结果表明 :1)镉是以Cd(OH) +形式在沉积物表面进行阳离子交换反应 .pH值是控制Cd 向固相迁移的主要因素 ,离子交换率E(% )随pH升高而增大 ,且在天然河水 pH为 8.0～ 8.5下接近最大值 ;2 )镉离子浓度由8.9× 10 - 7mol·L- 1 增大到 3× 8.9× 10 - 6mol·L- 1 时 ,离子交换率降低 ;3)河水中有2 .7× 10 - 6 mol·L- 1 甘氨酸存在时 ,会提高离子交换率 ;4 )转化沙和未转化沙分别对镉的吸附作用不同 ,后者大于前者 ,与理论推断相一致 .
The ion exchange rate E (%) -pH curve of the interaction between surface sediment and cadmium liquid-solid interface in the Yellow River and the effect of glycine in the water on the curve were studied.The experimental results showed that: 1) OH) + forms on the surface of the sediments. The pH value is the main factor controlling the migration of Cd to the solid phase. The ion exchange rate E (%) increases with the increase of pH, 2) the ion exchange rate decreased when the Cd2 + concentration was increased from 8.9 × 10-7 mol·L-1 to 3 × 8.9 × 10-6 mol·L-1; 3) In the presence of 10-6 mol·L -1 glycine, the ion exchange rate will increase; 4) The adsorption of cadmium by the conversion sand and unconverted sand is different, the latter is greater than the former, which is consistent with the theoretical inference.