pH对铜在黄土中吸持及其形态的影响

用黄土为吸持剂,以石英砂作对照,研究了pH对铜的吸持及形态的影响,并用MINTEQA2模型对铜离子的沉淀形态进行了理论计算.结果表明:无论吸持剂是石英砂还是黄土,随着pH的升高,吸持曲线都分为3区:低pH微吸持区、中pH吸持增长区和高pH强吸持区.含沙量一定,随着铜液初始浓度的增加,吸持量、可交换态含量和碳酸盐结合态含量均增加;铜液初始浓度一定,随着含沙量的增加,吸持量、可交换态含量和碳酸盐结合态含量均减少.MINTEQA2模型计算结果表明,对于不同的吸持剂,铜离子发生沉淀的比例及沉淀的物质组成是不同的;以黄土为吸持剂时,中pH范围内随着含沙量的增加铜离子沉淀的比例减少.

Effect of pH on Copper Sorption by the Loess and Its Species

To study the effect of pH on copper sorption and species, loess was taken as sorbent in this research, and control experiments were conducted with quartz. All the curves of sorption amount\|pH showed three regions, namely, sorption amount increased slowly at low pH, then increased quickly with the rise of pH, and reached the maximum amount at high pH. Copper of sorbed, exchangeable and bound to carbonate decreased with the increase in sediment concentration at constant Cu concentration, and increased with the increase in Cu concentration at constant sediment concentration. The MINTEQA2 model results showed that the proportions of precipitates and their compositions were different for loess and quartz, and the proportions of precipitates decreased with the concentrations of loess.