【摘要】 通过间歇震荡平衡法研究了膨润土对4种重金属离子Cd2+、Zn2+、Cu2+、Pb2+的竞争性吸附特性及其机制。研究结果表明:与单一离子体系比较,膨润土在竞争体系中对Cd2+、Zn2+、Cu2+、Pb2+4种重金属离子的吸附量均呈下降趋势。竞争体系下,其它重金属离子的存在显著抑制了膨润土对Cd2+的吸附,降幅为19.20%~37.50%,而对Pb2+的吸附能力几乎没有影响,降幅仅为0.41%~2.83%。膨润土对4种重金属离子的富集系数,其大小顺序依次为Pb2+>Cu2+>Zn2+>Cd2+。该选择性吸附顺序与重金属离子的一级水解常数密切相关。更多还原

【Abstract】 The influence of bentonite on the competitive adsorption characteristic of Cd2+,Zn2+,Cu2+ and Pb2+ were studied under the conditions of pH=6,T=25℃ and low concentration of heavy metals.The results showed that adsorption of lead ions was decreased insignificantly in competitive adsorption condition,whereas a dramatic decrease was observed on the adsorption of cadmium ions by the presence of lead,copper and zinc ions.As compare to single system the enrichment coefficients of Cd2+ ions in competitive system reduced by 19.20%-37.50%,while Pb2+ ions reduced by 0.41%-2.83%.The enrichment coefficients of Cd2+,Zn2+,Cu2+ and Pb2+ ions by bentonite follow the descending order: Pb2+>Cu2+>Zn2+>Cd2+.There was a good correction between this order and first hydrolysis constants of heavy metal ions.更多还原