Micron-sized silica gel particles were surface-modified with coupling agent -aminopropyltrimethoxysilane (AMPS)

obtaining the modified particles AMPS-SiO2.A redox initiating system was constituted by the amino groups on the surface of AMPS-SiO2 particles and persulfate in the solution

and the surface-initiated graft-polymerization of 2-hydroethyl methacrylate was performed

resulting in the grafted particles PHEMA/SiO2.Subsequently

a polymer reaction of the grafted PHEMA was carried out

and it was the nucleophilic substitution reaction between the hydroxyl group of the grafted PHEMA and the chloromethyl group of 5-chloromethyl-8-hydroxyquinoline (CHQ).As a result

the 8-hydroxyquinoline-functionalization transform of the grafted PHEMA was realized

obtaining the functional composite particles HQ-PHEMA/SiO2.The two kinds of particles were characterized by several methods.In this work

the graft-polymerization mechanism for the amino group-persulfate initiation system was mainly investigated

and the mechanism of the substitution reaction between the hydroxyl group of the grafted PHEMA and the chloromethyl group of CHQ was also explored in depth.Finally

the chelating adsorption property of HQ-PHEMA/SiO2 for heavy metal ions was preliminarily examined.The experimental results show that the amino group-persulfate initiation system has very high initiation activity

and it can effectively initiates the graft-polymerization of HEMA on silica gel particles.At room temperature (30℃)

the grafted particles PHEMA/SiO2 with high grafting degree (40 g/100 g) can obtained.The substitution reaction between the hydroxyl groups of the grafted PHEMA and CHQ has a reaction mechanism of SN1

and using the solvent with strong polarity is advantageous to the reaction.The functional particles HQ-PHEMA/SiO2 possess very strong chelating adsorption ability for heavy metal ions.The functional composite particles are promising and potential in the analysis and separation fields.