CS/PVA微球的制备及其对重金属离子吸附研究

Preparation of CS/PVA Microspheres and Their Adsorption Properties for Heavy Metal Ions

利用聚乙烯醇和戊二醛通过化学交联对壳聚糖进行改性,制备了壳聚糖/聚乙烯醇(CS/PVA)微球,采用傅里叶变换红外光谱、X射线衍射和扫描电镜对CS/PVA微球进行了表征,考察了pH值、吸附时间和重金属离子(Cu^(2+)、Fe^(3+)、Pb^(2+)、Cd^(2+))溶液初始浓度对CS/PVA微粒吸附性能的影响,并进行了吸附动力学研究。结果表明:CS/PVA微球吸附溶液中重金属离子的最佳pH值为7;准二级动力学模型较好地拟合了4种重金属离子的吸附试验数据,表明其吸附过程以化学反应为主,其中金属螯合作用占主导作用;利用Langmuir等温线模型拟合得到的CS/PVA微球对溶液中Cu^(2+)和Cd^(2+)的最大吸附容量分别为52.33 mg/g和57.81 mg/g,CS/PVA微球对溶液中Fe^(3+)、Pb^(2+)的吸附更符合Freundlich等温吸附模型,其对Pb^(2+)的吸附率最大。

Chitosan/polyvinyl alcohol(CS/PVA)microspheres are prepared by cross-linking and modifying chitosan with polyvinyl alcohol and glutaraldehyde,and characterized by FTIR,XRD and SEM.The effects of experimental parameters including pH value,contact time,initial concentration of metal ions solution,i.e.Cu^(2+),Fe^(3+),Pb^(2+)and Cd^(2+),on the adsorption performance of CS/PVA microspheres are investigated.The results show that the optimum pH value for adsorption is 7;the pseudo-second-order kinetic model fits the experimental data well for four metal ions,indicating that the adsorption process is dominated by che-mical reaction,in which metal chelation is dominant.The adsorption of Cu^(2+)and Cd2+in solution is more in line with the Langmuir isotherm model,and the maximum adsorption capacity of them is 52.33 mg/g and 57.81 mg/g respectively.In addition,the adsorption of Fe^(3+)and Pb^(2+)in solution by CS/PVA microspheres is more in line with the Freundlich isothermal adsorption model,and the adsorption rate of Pb^(2+)is the highest.