Conjugated microporous polymers containing benzothiazole groups for the efficient removal of RhB from water

Abstract

Conjugated microporous polymers (CMPs) are widely used as adsorbents due to their unique advantages, including microporous structure, large π-conjugated system, and structural stability. In this study, three types of CMP adsorbents (B-BTD-CMPs) containing different amounts of benzothiadiazole groups were obtained through Suzuki-Miyaura cross-coupling polycondensation reactions to investigate their performances in organic dye removal. The high charge density of nitrogen atoms in benzothiadiazole groups facilitates binding of small molecule dyes through a variety of non-covalent interactions. The results showed B-BTD-1,2,4,5, which containing the most benzothiadiazole groups, had the highest adsorption capacity of for rhodamine B (RhB) up to 531.20 mg g− 1. Furthermore, the adsorption performances of these CMPs on RhB under acidic, neutral, and basic conditions were almost identical, suggesting excellent acid and alkaline resistance. The adsorption capacity of CMPs decreased by less than 10% after five cycles, indicating excellent cyclic stability. It can be deduced that B-BTD-CMPs with stable structures and properties are excellent candidate adsorbents for dye wastewater treatment. This study also demonstrates that introducing N-containing functional groups into porous polymers is beneficial for the adsorption of small-molecule dyes, providing new design ideas for absorbents for dye wastewater treatment.