具有高离子识别能力的镉离子表面印迹材料的制备及其离子识别机理的研究

Studies on Preparation of Cd^(2+) Ion Surface-Imprinted Material with High Ion Recognition Ability and Its Ion Recognition Mechanism

采用氨基-过硫酸盐氧化还原引发体系,先实现了甲基丙烯酸羟乙酯(HEMA)在微米级硅胶微粒表面的引发接枝聚合,制得高接枝度的接枝微粒PHEMA/SiO2.然后使接枝大分子PHEMA的侧羟基与5-氯-8-羟基喹啉(CHQ)发生亲核取代反应,将8-羟基喹啉(HQ)基团键合在接枝大分子侧链,使接枝大分子PHEMA实现8-羟基喹啉功能化转变,制得表面含有高密度HQ基团的功能接枝微粒HQ-PHEMA/SiO2,考察研究了功能微粒HQ-PHEMA/SiO2对Cd2+离子的强螯合吸附作用.在此基础上,采用本课题组建立的新的分子表面印迹技术,以Cd2+离子为模板离子,二氯乙醚为交联剂,对接枝在硅胶表面的功能大分子链HQ-PHEMA进行了离子印迹,制备了Cd2+离子表面印迹材料IIP-HQP/SiO2,深入考察研究了其离子识别与结合特性.实验结果表明,该离子表面印迹材料对Cd2+离子具有特异的识别选择性与优良的结合亲和性,相对于Cu2+和Pb2+两种对比离子,印迹材料IIP-HQP/SiO2对Cd2+离子的识别选择性系数分别高达25.52和22.91,显示出超高的离子识别能力.

Hydroxyethyl methacrylate（HEMA） was graft-polymerized on micron-sized silica gel particles via surfaceinitiated graft-polymerization with amino/persulfate redox initiating system,obtaining the grafted particles PHEMA/SiO2 with a high grafting degree.Subsequently,the nucleophilic substitution reaction between the grafted PHEMA and 5-chloromethyl-8-hydroxyquinoline（CHQ） was carried out,and the 8-hydroxyquinoline-functionalization transformation of the grafted particles PHEMA/SiO2 was realized,preparing the functional grafted particles HQ-PHEMA/SiO2.The strong chelating adsorption property of HQ-PHEMA/SiO2 towards Cd2＋ ion was deeply investigated.On that basis,the ion imprinting towards the functional grafted macromolecules HQ-PHEMA was conducted with Cd2＋ ion as the template ion and dichloroether as crosslinker by using the novel surface imprinting technique found by our research group,and Cd2＋ ion surface-imprinted material IIP-HQP/SiO2 was prepared.The ion recognition and combination characters of IIP-HQP/SiO2 were examined in detailed.The experimental results show that this ion imprinted material has excellent recognition selectivity and combination affinity for the template ion,Cd2＋ ion.Relative to Cu2＋ and Pb2＋ ions as two contrast ions,the selectivity coefficients of IIP-HQP/SiO2 for Cd2＋ ion reach up to 25.52 and 22.91,respectively,displaying ultrahigh ion recognition ability.