Adsorption behavior of a tri-functionalized imprinted resin with high selectivity for 5-sulfosalicylic acid: Batch experiments and DFT calculation

The presence of aromatic compounds with multiple functional groups such as 5-sulfosalicylic acid (SSA) in water bodies is a threat to aquatic organisms and human health. Phenol (PH) with the -OH group, benzoic acid with -COOH and benzenesulfonic acid (BSA) with -SO3H can be considered as SSA structural unit. In this study, three functional monomers, namely, N-methylallylamine, diallylamine, and triallylamine, with strong affinity for PH, BA, and BSA, respectively, were selected from 16 monomers by using density functional theory (DFT). Molecularly imprinted resin (MIP-4) with tri-functional groups and excellent selectivity for SSA was synthesized using a macroporous polystyrene resin (NDA-1800) as the carrier. In binary systems, MIP-4 exhibited excellent imprinting effect and adsorption selectivity for SSA. X-ray spectroscopy data and DFT calculations illustrated that the adsorption of SSA on MIP-4 was mainly dependent on the strong electrostatic interaction between the protonated amine group on the resin and -SO3- of SSA, as well as, the hydrogen bond between the neutral amine group and -OH and -COOH of SSA; the order of the three functional groups in identification was -OH > -COOH > -SO3H. In addition, the adsorption performance of MIP-4 was retained after five adsorption–desorption cycles.