Study On Preparation And Adsorbing Properties Of Polystyrene Resins With Multi-porous Structures

Polystyrene based resins were prepared by suspension polymerization in the presence of divinylbenzene as cross-linker and heptane as porogens using glutin as dispersion stabilizer. In order to change the structure and the polarity of the polymeric adsorbent resins were adjusted by adding some polar monomer such as methyl methacrylate (MMA) or methacrylate (MA) in the polymerization system of styrene with divinylbenzene.The effects of amounts of divinylbenzene and heptane on structure and polarity of the polymeric adsorbent have been studied. The apparent density and true density of the polymeric adsorbent was an inverse proportion for percent of divinylbenzene in monomers, but the pore volume and the surface area was direct proportion to it. The factors such as the heating-up speed, stir speed and other different preparing conditions were studied. The results indicated that the polarities and amount of the polar monomer have an important influence on their physical structure and surface area. The surface areas of resulting resins general reduced with the increase of the adding amount of polarities. The heating-up speed is 5℃/h from 60℃, and stir speed is 200-300 r/min, the prepared polymeric adsorbent granules are major in the size of 0.4～0.8mm.The optimizing conditions of multi-porous resins were obtained based on the characterization of FTIR, SEM and ST-2000 surface area measurement instrument. Methylene blue was elected as the model molecule to study the static adsorption properties of the resins. The effects of methylene blue concentration, pH and solution temperature on adsorption capacity were explored. The experimental results indicate that pore sizes of synthesized resins have an important influence in adsorption process. The surface area will play an important role when pore sizes have a suitable value. The resins with 2 wt% MMA or 5 wt% MA, the surface areas respectively are 311 m2/g, 288 m2/g, and the pores size are 2.94 nm, 2.38nm have better adsorption for methylene blue, and the experimental data are fitted to the Fredunlich equilibrium.