Polar-modified post-cross-linked polystyrene and its adsorption towards salicylic acid from aqueous solution

A novel polar-modified post-cross-linked polystyrene PGDpc_D was prepared by the Friedel-Crafts alkylation reaction of the pendent vinyl groups and amination reaction with diethylenetriamine (DETA). The Brunauer-Emmett-Teller (BET) surface area and pore volume of the starting copolymer PGD increased significantly after the post-cross-linking, and the surface polarity of the post-cross-linked polystyrene PGDpc improved greatly after the amination reaction. Batch adsorption runs of salicylic acid on PGDpc_D were studied using its precursors (PGD and PGDpc) and the non-polar post-cross-linked polystyrene PDVBpc as the references. Experimental results indicated that PGDpc_D possessed a much enhanced adsorption towards salicylic acid in comparison with PGD, PGDpc and PDVBpc, and the equilibrium data could be characterized by both of the Langmuir and Freundlich models. The adsorption was a fast process and the kinetic data obeyed the micropore diffusion model. Column adsorption-desorption experiments suggested that PGDpc_D was a potential candidate for treatment of salicylic acid from aqueous solution.