Preparation of p-phenylenediamine modified polymer brush grafted PS-DVB materials for highly selective adsorption of flavonoids

Abstract

Due to the low adsorption capacity and poor adsorption selectivity of the resins, the separation of flavonoids was still a challenge in the separation field. In this work, a novel polymer microspheres Polystyrene-divinylbenzene-poly(Glycidyl methacylate- p-phenylenediamine(PS-DVB-PGMA-PPD) containing PGMA polymer brushes was synthesized by combining surface-initiated atom-transfer radical polymerization (SI-ATRP) and p-phenylenediamine (PPD) modification.The physical and chemical properties of materials were characterized by different analytical methods. It was found that the adsorption process conformed to the pseudo–second–order kinetic model and Freundlich isotherm model. The thermodynamic parameters of quercetin adsorption process indicated that the adsorption was spontaneous and endothermic. The adsorption experiments showed that the polymer PS-DVB-PGMA-PPD had the best adsorption capacity onto quercetin, and the maximum adsorption capacity was 72.68 mg/g at 318.15 K. Compared with other flavonoids and alkaloids (such as theophylline, berberine and rutin), PS-DVB-PGMA-PPD had higher adsorption capacity and better selectivity for quercetin. Hydrogen bond interaction and π - π interaction may drive the adsorption process of quercetin. In addition, When the ethanol content was 95%, the desorption rate can reach 80.9%. PS-DVB-PGMA-PPD still had good adsorption performances for quercetin after five cycles, which indicated that the material had good renewable performances. In general, the results showed that its adsorption capacity for flavonoids from complex biological systems was excellent.