Preparation of Functional Grafted Particles PVI-SiO2 and Preliminary Study of Their Adsorption Characters

Vinylimidazole(VI) was graftpolymerized on micronsized silica gel particles in a manner of “graft from” in a solution polymerization system by right of the mediation of the coupling agent 3methacryloxypropyl trimethoxysilane (MPS), resulting in the functional grafted particles PVI-SiO2. The grafted particles PVI-SiO2 were characterized by infrared spectrum (FT-IR), scanning electron microscope (SEM) and thermogravimetric analysis (TGA). The Zeta potential of the grafted particles was determined. The effects of the main factors on the graft polymerization were examined emphatically, and their adsorption character for chromate ion and heavy metal ions were preliminarily explored. The experimental results show that as the general rule of the graft polymerization on solid particles, for this graft system, the formed grafted polymer layer during the graft polymerization is a hindrance to the subsequent graft polymerization, and the reaction temperature and the used amount of initiator affect the graft polymerization intensively. Under the suitable conditions, the grafting degree of PVI on the surfaces of the grafted particles(100 g) can get up to 21.63 g. In a wider pH range, the Zeta potential of the grafted particles PVI-SiO2 is a greater positive value. By right of the strong electrostatic interaction, the grafted particles PVI-SiO2 have strong adsorption ability towards chromate anions, and the adsorption capacity can reach 120 mg/g. By virtue of the coordination, the grafted particles PVI-SiO2 can produce strong adsorption ability for heavy metal ions.