Imidazole-modified polymers and their adsorption of salicylic acid from aqueous solution

Hyper-cross-linked polymers modified with chemical groups are excellent porous materials for the adsorption of aromatic compounds from aqueous solution. Herein two kinds of imidazole-modified polymers, imidazole-modified hyper-cross-linked polymer with two steps (N-HCLPs) and imidazole-modified hyper-cross-linked polymer with one step (N-LCMPs) were comparatively prepared from macroporous chloromethylated polystyrene (CMPS), and they were employed as the adsorbents for the adsorption of salicylic acid from aqueous solution. The results indicated that N-HCLPs owned higher specific surface area and pore volume than N-LCMPs while N-LCMPs had much higher imidazole moieties than N-HCLPs. The adsorption results showed that these two polymers were efficient for the adsorption of salicylic acid, N-LCMPs (295.2 mg/g) had a higher capacity than N-HCLPs (263.2 mg/g), implying that acid–base interaction and hydrogen bonding was mainly responsible for the adsorption. The adsorption process was very fast and the equilibrium was attained within 120 min, the pseudo-second-order rate model was more suitable to characterize the kinetic data.