Studies On Preparation Of Ion Surface-imprinted Material Based On8-Hydroxyquinoline Functional Graft Particles And Its Ion Recognition-combination Ability

In the paper, Hydroxyethyl methacrylate （HEMA） was grafted on micron-sizedsilica gel particles via surface-initiated graft-polymerization with amino-persulfate redoxsystem, obtaining the grafted particles PHEMA/SiO₂with a high degree. Subsequently,the nucleophilic substitution reaction of the grafted PHEMA with5-chloromethyl-8-hydroxyquinoline （CHQ） as reagent was carried out, and the8-hydroxyquinoline-functionalization transform of the grafted particles PHEMA/SiO₂was realized, preparing the functional grafted particles HQ-PHEMA/SiO₂.On that basis,Heavy metal ions and Rare earth ions surface-imprinted material IIP-HQP/SiO₂wasprepared by using the novel surface imprinting technique found up by our researchgroup. Then, both static and dynamic methods were adopted to study the recognitionproperty for Heavy metal ions and Rare earth ions. ion imprinted polymers as a solidadsorben which can carry on the selective adsorption for Heavy metal ions and Rareearth ions of water medium, would have great significance and good applicationprospect in the environmental protection，separation and hydrometallurgy fields。Micron-sized silica gel particles were surface-modified with coupling agentγ-aminopropyltrimethoxysilane（AMPS）, obtaining the modified particlesAMPS-SiO₂.A redox initiating system was constituted by the amino groups on the surface ofAMPS-SiO₂particles and persulfate in the solution, and the surface-initiatedgraft-polymerization of2-hydroethyl methacrylate was performed, resulting in thegrafted particles PHEMA/SiO₂. The two kinds of grafting particles were characterized with FTIR, TGA and SEM methods. The effects of the main factors on the graftpolymerization of HEMA were examined. The experimental results show that in thesurface grafting polymerization process, the grafting degree of PHEMA can get up to40g/100g by controlling temperature, time the consistence of HEMA and the usedamount of initiator, The best reaction conditions are as follows: T=30℃, Time=12h, theused amount of initiator=1.0%, Monomer concentration=6.0%.In the presence of acid-acceptor Na₂CO₃,the nucleophilic substitution reaction ofthe grafted PHEMA with5-chloromethyl-8-hydroxyquinoline （CHQ） as reagent wascarried out, and the8-hydroxyquinoline-functionalization transform of the graftedparticles PHEMA/SiO₂was realized, preparing the functional grafted particlesHQ-PHEMA/SiO₂,Its chemical structure was characterized by infrared spectrum. Theeffects of main factors on the substitution reaction were examined, and the reactionmechanism was explored. The experimental results show that the substitution reactionbetween the hydroxyl groups of the grafted PHEMA and CHQ has a reaction mechanismof SN1, and using the solvent DMSO with strong polarity is advantageous to the reaction,and90℃is a appropriate temperature.In this research work, the behaviours of the graft particles HQ-PHEMA/SiO₂towards Cu²⁺and Ni2+were examined preliminary, The experimental results show thatThe functional particles HQ-PHEMA/SiO₂possess very strong chelating adsorptionability for heavy metal ions. the adsorption capacity can get up to60mg/g （0.95mmol/g）and46mg/g （0.80mmol/g）at30℃temperature.The ion imprinting towards the functional grafted macromolecules HQ-PHEMAwas conducted with Cd²⁺ion or Pr³⁺ion as the template ion and dichloroether ascrosslinker by using the novel surface imprinting technique found up by our researchgroup, and Cd²⁺ion or Pr³⁺ion surface-imprinted material IIP-HQP/SiO₂was prepared.With the other metal ions,two Heavy metal ions or two Rare earth ions, as a contrast compound, both static and dynamic methods were adopted to study the recognition andcombination property for Cd²⁺ion or Pr³⁺ion and the separation ability towards metalions in the hybrid aqueous solution. The experiment results showed that IIP-HQP/SiO₂have obvious recognition selectivity and fine binding affinity for Cd²⁺ion or Pr³⁺ion,and the selectivity coefficient is equal to25.52or22.91with respect to Cu²⁺ion or Pb2+ion, The optimal preparation conditions of imprinted polymers is determined: T=45℃and the ratio of amount of crossing agent and amount of HEMA is1:3. The selectivitycoefficient is equal to5.22or5.12with respect to La³⁺ion or Ce³⁺ion, and the bestimprinting reaction condition is determined: T=45℃and the ratio of amount of crossingagent and amount of HEMA is1:3.5. Besides, with a diluted aqueous solution ofHCl（0.1mol/L） as the eluent, IIP-HQP/SiO₂has excellent elution property.