改性水凝胶的制备及其对Pb^2＋、Cd^2＋吸附性能研究

Preparation of a Novel Modified Hydrogel and Study of Its Adsorption Performance

采用60Co-γ射线低温辐射技术,以丙烯酸羟乙酯(HEA)和N-乙烯基甲酰胺(NVF)为共聚单体,合成了一种新型共聚物水凝胶:聚(丙烯酸羟乙酯/N-乙烯基甲酰胺)[p(HEA/NVF)],并采用三乙烯四胺(TETA)对其进行胺化改性,制得一改性水凝胶:聚(丙烯酸羟乙酯/N-乙烯基甲酰胺)-三乙烯四胺[p(H/V)-T].对制备的p(HEA/NVF)凝胶进行了SEM分析和FTIR分析,并对改性后的p(H/V)-T进行XPS分析及FTIR分析.研究了改性前后水凝胶对重金属Pb2+、Cd2+的吸附性能,改性后水凝胶对Pb2+、Cd2+的吸附动力学,以及重金属离子初始浓度、pH值等对改性凝胶吸附性能的影响,并对吸附重金属前后的水凝胶进行电子能谱分析.SEM分析表明,p(HEA/NVF)水凝胶是一种具有多孔结构的高分子材料;吸附实验结果表明,相比较p(HEA/NVF),p(H/V)-T对Pb2+的吸附量增加了700%,对Cd2+的吸附量增加了600%;p(H/V)-T对Pb2+、Cd2+的吸附量随着pH的升高而增加,吸附过程满足准二级动力学方程,并均能较好地符合Freundlich和Langmuir等温吸附模型(R2>0.95);红外分析证实,HEA和NVF已成功聚合为一新型共聚物水凝胶,且多胺基团已被成功地接于共聚物水凝胶表面;XPS分析得出,改性后水凝胶p(H/V)-T对重金属Pb2+、Cd2+的吸附机制为两者之间的螯合作用.

A novel copolymer hydrogel poly（Hydroxyethyl methacrylate /N-Vinylformamide） [p（HEA /NVF） ]was prepared by 60Co-γ induced copolymerization,using low-temperature radiation technique.Triethylenetetramine（TETA） was applied to modify the prepared hydrogel into an ammoniated hydrogel poly（Hydroxyethyl methacrylate/N-Vinylformamide）-TETA [p（H/V）-T].The two hydrogels prepared were characterized by using FTIR spectrometry and the p（HEA/NVF） was scanned by SEM.Moreover,the p（H/V）-T hydrogels were analyzed by XPS before and after adsorption.The adsorption capacities of Pb2 ＋,Cd2 ＋ on p（HEA/NVF） and p（H/V）-T were investigated.And the effects of pH,time and initial metal ion concentration on the adsorption of Pb2 ＋,Cd2 ＋ by p（H/V）-T were examined in batch experiments.SEM photos showed that p（HEA/NVF） hydrogel is a macroporous polymer material.Compared to the p（HEA/NVF） hydrogel,the adsorption capacities of Pb2 ＋,Cd2 ＋ on p（H/V）-T increased by 700% and 600%,respectively.The adsorption behaviors for Pb2 ＋and Cd2 ＋ confirmed that the adsorption on p（H/V）-T followed the pseudo-second-order rate equation and was fitted to both Langmuir and Freundlich adsorption model（R2 0.95）.Besides,the adsorption capacities of p（H/V）-T increased with increasing pH values.The FTIR spectra verified that p（HEA/NVF） was indeed a copolymer of HEA and NVF monomers,and the multi-amine groups have been successfully grafted to the surface of the copolymer hydrogel.The XPS analysis concluded that the mechanism of Pb2 ＋ and Cd2 ＋ by p（HEA/MALA） could be the chelation between-NH2 and metal ions.