蒙脱石-钢渣复合吸附颗粒对水中Cd^(2+)的吸附及其它离子的影响研究

Research on Cd^(2+) Adsorption and Effects of Heavy Ions of Montmorillonite-Slag Composite Particle

以蒙脱石和钢渣为原料,采用工业淀粉作为添加剂制备蒙脱石-钢渣复合吸附颗粒,探究其对水中Cd^(2+)的吸附性能及其机理.研究结果表明,蒙脱石占复合吸附颗粒质量比为50%时,对Cd^(2+)的吸附性能最好.质量比为1∶1的蒙脱石-钢渣复合吸附颗粒在用量为15g·L^(-1)和pH值为5.5～6.5时,吸附效果最佳.在温度为25℃,pH为5.6时,1.5g质量比为1∶1的蒙脱石-钢渣复合颗粒对浓度为100mg·L^(-1)的Cd^(2+)溶液(100mL)吸附60min后,废水中Cd^(2+)的吸附率达到97.47%.通过二级动力学方程拟合复合吸附颗粒对Cd^(2+)的吸附反应,相关系数为0.998 0.吸附颗粒对水中Cd^(2+)的吸附等温式符合Langmuir方程,相关系数为0.974 5,Cd^(2+)的饱和吸附量达到9.76mg·g^(-1).Cu^(2+)和Pb^(2+)对废水中Cd^(2+)的吸附具有竞争影响,可以降低其吸附量,且Pb^(2+)的影响较大.

Taking montmorillonite and slag as raw materials,the composite adsorbent was prepared using industry starch as an additive to study the adsorptive property of Cd^2＋.The results show that the adsorption performance reaches the optimal when montmorillonite in the proportion of composite adsorbent was 50%.The best condition of 1∶1 montmorillonite-slag composite particle is that the absorbent dosage with 15 g·L^-1,pH value from 5.5 to 6.5.The Cd^2＋ removal rate reached 97.47%in solution with 100 mg/L Cd^2＋ concentration（1.5 g composite particle）with 60 min in the condition of 25 ℃ and5.6 pH value.The adsorption process of composite particle for Cd^2＋ could be well simulated by pseudosecond-order kinetics equation（R^2=0.996 0）.The adsorption reaction is in line with the Langmuir model with coefficient of 0.974 5,and the maximum adsorption capacity is 9.76 mg·g^-1.Further analysis showed that Cu^2＋ and Pb^2＋ have the competitive effect on Cd^2＋ adsorption,which resulted in the decrease of adsorption quantity.And the competitive influence of Pb^2＋ is stronger than Cu^2＋.