Removal of Pb~（2＋）,Cu~（2＋） and Cd~（2＋） from composite pollution aqueous solution by zeolite 4A
4A沸石对复合污染水体中Pb2+、Cu2+和Cd2+的去除

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.