Preparation And Adsorption Properties Of Silica Gel Composite Microspheres Encapsulated By Functionalized Polystyrene

In this thesis, the preparation of four new kinds of composite microshere was reported.The structures and patterns were characterized by FTIR, SEM, EDX, TG, GPC.The adsorption of the composites for Cu(II), Ag(I), Au(III), Mn(II), Fe(III), Co(II), Ni(II), Zn(II), Cd(II), Hg(II), Pt(IV), Pb(II) were studied.1. By Grafting polymerization of styrene on silica gel surface, then via nitration, deoxidization, the composite microsphere of polystyrene containing amino encapsulation silica gel (SG-PS-NH2) was synthesized, the static adsorption capability for Cu(II), Ag(I), Au(III), Mn(II), Fe(III), Co(II), Ni(II), Zn(II), Cr(VI), Cd(II), Hg(II), Pd(II), Pt(IV), Pb(II) were investigated. The influence of pH of the solution, the thermodynamics and kinetics of adsorption for Cu(II), Ag(I), Au(III) were also inspected. The results indicated that the isothermal adsorption could be described by Langmuir equation, the adsorption rate is mainly controlled by liquid film diffusion, and the adsorption selectivity and dynamics properties for Au(III), Ag(I) are better.2. With SG-PS-NH2 as matrix, via diazotization, coupling with salicylic acid, the composite microsphere of silica gel encapsulated by polystyrene coupling with salicylic acid (SG-PS- azo-SA) was synthesized, the static adsorption capability for Cu(II), Ag(I), Au(III), Mn(II), Fe(III), Co(II), Ni(II), Zn(II), Cd(II), Hg(II), Pb(II) were determined. The influence of pH of the solution, the thermodynamics and kinetics of adsorption for Cu(II), Ag(I), Au(III) were also inspected. The results indicated that the isothermal adsorption obeys the Langmuir curve, the adsorption rate is mainly controlled by liquid film diffusion, and the adsorption selectivity and dynamics properties of Au(III) are excellent.3. With SG-PS-NH2 as matrix, via diazotization, coupling with sulphur salicylic acid, a novel composite microsphere of silica gel encapsulated by polystyrene coupling with sulphur salicylic acid (SG-PS-azo-SSA) was synthesized, the static adsorption capability for Mn(II), Co(II), Ni(II), Zn(II), Cd(II), Hg(II), Cd(II), Pd(II), Fe(II), Hg(II), Cu(II), Ag(I) and Au(III) were investigated. The experimental results showed this composite had high adsorption selective and excellent kinetic properties for Cu(II), Ag(I) and Au(III). And the adsorption capacities for the three ions all increased with the decreasing of acidity. The results also showed that the Langmuir model is better than the Freundlich model to describe the isothermal process of this composite for Cu(II), Au(III), except Ag(I). Three adsorption- desorption cycles demonstrated that this composite are suitable for reuse without considerable change in adsorption capacity.4. With SG-PS-NH2 as matrix, via diazotization, coupling with imidazole, the composite microsphere of silica gel encapsulated by polystyrene coupling with imidazole (SG-PS-azo-IM) was synthesized, the static adsorption capability for Cr(II), Mn(II), Fe(III), Ni(II), Cu(II), Zn(II), Hg(II), Pd(II), Pb(II), Pt(IV), Ag(I), Au(III) were studied. The influence of pH of the solution, the thermodynamics, kinetics and selectivity of adsorption, and the preconcentration to Au(III) were also inspected. The results showed that with the decreasing of acidity of solution, the adsorption capacities for Au(III) increases, the isothermal adsorption could be described by Langmuir equation, the adsorption rate is mainly controlled by liquid film diffusion, and the adsorption selectivity and dynamics properties of Au(III) are outstanding. An enrichment factor of 5.28 is obtained with a sample consumption of 25.0mL and the original concentration of 0.10-0.20μg/mL.