改性蛋壳材料对重金属离子的去除机理研究

Mechanism study on heavy metal removalwith modified eggshell

以废弃蛋壳为主要原料,通过微波法和铁改性法分别合成吸附材料ME和FE,采用扫描电镜、X射线衍射以及比表面积分析仪进行表征,并考察材料对废水中Cu^2+、Cd^2+、Pb^2+的吸附性能及其影响因子(反应时间、吸附剂投加量、重金属离子初始质量浓度以及溶液pH)。结果表明:ME对Cu^2+、Cd^2+的吸附效果较好,当废水中Cu^2+、Cd^2+的初始质量浓度为50mg·L^-1、ME的投加量为0.6g·L^-1、pH=4时,反应20min后,ME对Cu^2+、Cd^2+的去除率均高达100%,其饱和吸附量分别为179.2、183.6mg·g^-1;FE对Pb^2+的吸附效果较好,当废水中Pb^2+的初始质量浓度为50mg·L^-1、pH=6时,FE对Pb^2+的饱和吸附量可达87.23mg·g^-1,Langmuir吸附等温方程可较好地描述该吸附过程。

Two kinds of adsorption materials called ME and FE were prepared from eggshell by microwave treatment and ferrous sulfate modification,respectively.They were characterized by scanning electron microscopy,X-ray diffractometer and specific surface area analyzer.The effects of reaction time,adsorbent dosage,initial concentration of heavy metals and pH on the adsorption performance of Cu^2+,Cd^2+ and Pb^2+in the wastewater were investigated.The results showed that ME was effective on the adsorption for Cu^2+and Cd^2+.When the initial concentration of Cu^2+ and Cd^2+was 50 mg·L^−1,ME dosage was 0.6 g·L^−1,and pH was 4,the removal efficiencies of Cu^2+and Cd^2+were up to 100%after 20 min,and the adsorption capacities were 179.2 and 183.6 mg·g^−1,respectively.FE was effective for the removal of Pb^2+.When the initial concentration of Pb^2+was 50 mg·L^−1 and pH was 6,the maximum adsorption capacity of FE for Pb^2+reached 87.23 mg·g^−1.The adsorption process can be described by Langmuir isotherm equation satisfactorily.