Boosted electrostatic interaction by surface sulfonation over Calixarene-TPE copolymer for prompt adsorption of cationic contaminates

Removal of cationic pollutants, including dyes, herbicides, and antibiotics from water is significant owing to their persistence, bioaccumulation, carcinogenicity, mutagenicity, and reproductive risks. In this paper, a calixarene-tetraphenyl ethylene containing copolymer adsorbent, named CP-TPE, was synthesized using the Suzuki-Miyaura coupling reaction between the resorcinol calixarene and tetraphenyl ethylene boric acid esters. Subsequently, the phenolic groups on the CP-TPE were further reacted with chlorosulfonic acid, resulting in a sulfonated product named CP-TPE-SO3H. The introduction of the sulfonate groups not only significantly improved the hydrophilicity of CP-TPE-SO3H but also enhanced the electrostatic interaction between CP-TPE-SO3H and cationic molecules, achieving an outstanding maximum adsorption capacity for paraquat (representative herbicide, 300.06 mg g−1) and tetracycline hydrochloride (representative antibiotic, 888.74 mg g−1), which surpassed the majority of reported polymeric adsorbents. Moreover, the k2 of CP-TPE-SO3H on TC (0.0407 g mg−1 min−1) reached the maximum value reported so far. This study demonstrated the significance and superiority of sulfonation modification in synthesizing POPs-based adsorbents, which can be potentially employed in real wastewater treatment.