蒙脱土-稻壳炭复合材料对Pb(Ⅱ)吸附特性研究

Study of adsorption characteristics of Pb^(2+) on montmorillonite-rice husk bio-charcoal composites

采用静态吸附实验,研究蒙脱土-稻壳炭复合材料对Pb^(2+)的吸附动力学和热力学特性,并考察吸附剂用量、共存离子及pH等因素对该复合材料吸附Pb^(2+)的影响。结果表明,复合材料对Pb^(2+)的吸附特性符合准二级动力学模型,等温吸附过程能较好地以Freundlich模型进行拟合,且是以物理吸附为主的自发的吸热反应。复合材料对Pb^(2+)的吸附量随吸附时间的延长先快速增加,后缓慢增加最终达到吸附平衡,且随着复合材料投加量的增加,Pb^(2+)的去除率增大。复合材料对水溶液中Pb^(2+)的吸附性能在pH为5时较好,吸附量达52.79 mg·g^(-1);不同浓度Ca^(2+)、Mg^(2+)均会对Pb^(2+)的吸附反应产生抑制作用,且Mg^(2+)的抑制作用更强。

Batch experiments were carried out to study the adsorption properties of PB2＋ on montmorillonite-rice husk carbon composites, and the effect of influencing factors such as the adsorbent dosage, coexisting ions, and pH on Pb2＋ sorption was investigated.The results showed that the adsorption of Pb2. was more consistent with the pseudo-second-order kinetic model.The isothermal adsorption of Pb2＋ on composites could be well fitted with the Freundlich isothermal model, and the adsorption process was a spontaneous endothermic reaction based on physical adsorption.With an increase in adsorption time, the adsorption capacity of Pb2＋ increased rapidly at first and then decreased gradually before, finally reaching the adsorption equilibrium.With an increase in the adsorbent dosage, the Pb2＋ removal rate increased.The highest Pb2＋ adsorption performance on the composites was observed at a pH of 5, and the adsorption capacity reached 52.79 mg· g-1.The presence of different concentrations of Ca2. and Mg2＋ in the solution inhibited Pb2＋ adsorption, and the inhibitory effect of Mg2＋ was stronger.