4A沸石对复合污染水体中Pb2+、Cu2+和Cd2+的去除

采用静态吸附法以4A沸石为吸附剂研究其对复合污染水体中Pb2+、Cu2+和Cd2+的竞争吸附特性,并探讨了影响吸附的环境因素。实验表明,在室温条件下,溶液pH5～6,4A沸石15 mg对10 mL复合污染溶液(Pb2+、Cu2+和Cd2+浓度分别为100 mg/L)吸附20 min时,对溶液中3种重金属的吸附去除率均可达99.8%以上。反应过程中4A沸石对3种重金属的吸附速率大小为Pb2+>Cu2+>Cd2+。复合污染水体中4A沸石对Pb2+、Cu2+和Cd2+的吸附符合Langmuir和Fre-undlich等温吸附方程,相关系数分别为0.9981、0.9901、0.9916和0.9638、0.9194、0.9689。经计算,4A沸石对Pb2+、Cu2+和Cd2+的饱和吸附量分别为129.9 mg/g、107.5 mg/g和99.0 mg/g。4A沸石吸附重金属离子达到吸附平衡的时间较短,对溶液pH值的适应性较好。吸附后的4A沸石可以再生利用,对铅离子洗脱重复利用性较铜离子和镉离子强。

Removal of Pb~（2＋）,Cu~（2＋） and Cd~（2＋） from composite pollution aqueous solution by zeolite 4A

Taking zeolite 4A as adsorbent,the experiment aims to study competitive adsorption characteristic of zeolite 4A on Pb2+,Cu2+,Cd2+ in compound contaminated water by adopting static adsorption method and discuss the environmental factors influencing adsorption.The result showed that at the usual temperature,after the solution of pH 5~6 with 15 mg of zeolite 4A had adsorbed 10 mL of compound contaminated solution(the concentrations of Pb2+,Cu2+ and Cd2+ were respectively 100 mg/L) for 20 minutes,the removal rate of three heavy metals can reach more than 99.8%.During the reaction process,the adsorption rate of zeolite 4A to the three heavy metals was Pb2+>Cu2+>Cd2+.The adsorption of zeolite 4A to Pb2+,Cu2+ and Cd2+ in compound contaminated water coincided with Langmuir and Freundlich isothermal adsorption equations,and correlation coefficients were 0.9981,0.9901,0.9916 and 0.9638,0.9194,0.9689,respectively.By calculation,the saturated adsorption capacities of zeolite 4A to Pb2+,Cu2+ and Cd2+ are 129.9 mg/g,107.5 mg/g and 99.0 mg/g,respectively.Zeolite 4A takes relatively shorter time to adsorb heavy metals ions to approach adsorption equilibrium,and it has good adaptation to pH of solution.Zeolite 4A can be recycled after adsorption.And it is easier for zeolite 4A to elute lead ions for recycling compared with copper ions and cadmium ions.