Study On Preparation Of Large Pore Size Polystyrene Adsorbent Resin

Polystyrene sorbent resins are widely used in extraction and separation due to their high specific surface area and rich pore structure.In order to increase the selective adsorption of the adsorbent and to increase the adsorption capacity of the adsorbent,polystyrene adsorbent resins with a certain degree of cross-linking are usually subjected to a secondary cross-linking reaction to improve the adsorption performance of the resin.In this paper,polystyrene-divinylbenzene P(ST-co-DVB)porous adsorbent resins with different cross-linkages and particle sizes were prepared by suspension polymerization using styrene and divinylbenzene as copolymer monomers,toluene as porogen agent and polyvinyl alcohol as stabiliser.P(ST-co-DVB)porous adsorbent resins with different degrees of cross-linking were then prepared by the Davankov post-cross-linking method usingα,α’-Dichloro-p-xylene as the post-cross-linking agent and anhydrous ferric chloride as the catalyst to obtain Hyper-crosslinked polystyrene(HCPS)adsorbent resins with high specific surface area and large pores.The comprehensive properties of the P(ST-co-DVB)porous adsorbent resins and the HCPS adsorbent resins were investigated using BET,FTIR,optical microscopy and TGA.The results showed that the P(ST-co-DVB)porous adsorbent resin was successfully synthesized,and its average pore size decreased with the increase of divinylbenzene content in the copolymer monomer,and the specific surface area increased with the increase of divinylbenzene content,while the specific surface area showed a trend of increasing and then decreasing with the increase of porogen agent content,and the specific surface area could reach up to 515 m~2/g.The stabiliser and stirring speed had a large effect on the particle size of the resin,and the highest yield of large particle size adsorbent resin was obtained at 0.02 g PVA and 50 rpm.HCPS adsorbent resins using different cross-linked P(ST-co-DVB)porous adsorbent resins as starting copolymers are strongly influenced by the degree of cross-linking of the starting copolymer,with the specific surface area and pore volume of the resin increasing after post-cross-linking,up to a maximum of 1174 m~2/g,while the average pore size decreases.The adsorption performance of polystyrene adsorption resin in methylene blue solution was further discussed to investigate the effect of adsorption time and different initial concentrations and p H values on the adsorption performance of the resin,and the adsorption process was fitted.The fitting results showed that the kinetics of the adsorption process of polystyrene adsorption resin on methylene blue was in accordance with the proposed secondary reaction model and the adsorption equilibrium process was in accordance with the Langmuir model for monolayer adsorption.Under the same conditions,the choice of polystyrene adsorption resin with higher specific surface area and larger pore size is favour for adsorption.