壳聚糖/聚乙二醇/丙烯酸吸附剂对Cu^2＋、Co^2＋和Ni^2＋的吸附选择性和重复利用性

Adsorption selectivity and reusability of chitosan/poly (ethylene glycol)/acrylic acid adsorbent for Cu^(2+),Co^(2+) and Ni^(2+)

采用扫描电镜(SEM)和红外光谱(FT-IR)对辉光放电电解等离子体(GDEP)技术引发制备的壳聚糖/聚乙二醇/丙烯酸(CS/PEG/AA)聚合物吸附剂的形貌和结构进行了表征.研究了该吸附剂对Cu^(2+)、Co^(2+)和Ni^(2+)的吸附选择性、重复利用性和解吸动力学行为,同时结合X射线光电子能谱(XPS)探讨了可能的吸附机理.结果表明,CS、PEG和AA发生接枝共聚形成聚合物,其表面呈现疏松、多孔的三维网络结构;吸附最佳pH为4.8;在含有Cu^(2+)、Co^(2+)和Ni^(2+)的混合溶液中,CS/PEG/AA对Cu^(2+)有较好的吸附选择性;在EDTA-4Na洗脱液中CS/PEG/AA具有优异的再生和重复利用性,解吸动力学符合解吸准二级模型;Cu^(2+)在CS/PEG/AA上的吸附是由离子交换、配位螯合等共同作用的复杂的物理化学过程.

The chitosan/poly（ ethylene glycol）/acrylic acid（ CS/PEG/AA） adsorbent was prepared using glow-discharge electrolysis plasma technique,and then characterized by SEM and FT-IR.The adsorption selectivity and reusability of adsorbent for Cu^2＋,Co^2＋and Ni^2＋were investigated in detail. In addition,the adsorption mechanism was also studied by using FT-IR and XPS. The results show that PEG and AA have been successfully grafted on CS.The adsorbent exhibits porous surface with three-dimensional network structure. The optimal pH for the removal of heavy metal ions is 4.8. The CS/PEG/AA has good adsorption selectivity for Cu^2＋with the coexistence of Co^2＋and Ni^2＋. The desorption behavior of CS/PEG/AA for Cu^2＋,Co^2＋and Ni^2＋in EDTA-4Na solution follows pseudo-second-order model. The adsorption of Cu^2＋by CS/PEG/AA is a complex physical-chemical process due to coordination between N atoms and Cu^2＋,ion-exchange between Na＋and Cu^2＋.