Thiazolyl-linked conjugated microporous polymers for enhancement adsorption and photocatalytic degradation of organic dyes from water

Abstract

Organic dyes and pigments are common examples of pollutants that have been drained to water resources. Subsequently, chemists searched for novel and efficient adsorbents for treatment of sewage water from coloring compounds. Conjugated microporous polymers (CMPs), which displayed high Brunauer Emmett and Teller (BET) surface area and porous morphology, beside other unique merits, solve this challenging situation by consuming dye molecules into their large and permanent pores, and degrading them in the presence of light. In this paper, we adopt a designed synthesis of new thiazolyl-linked CMPs containing bicarbazole, bifluorenylidene, and biphenylethene building blocks, namely: BC-TT, BF-TT, and BIPE-TT CMPs, respectively. All the common characterizations including chemical, physical, and photophysical were conducted for the as-synthesized CMPs. In addition to their significant surface areas that reach 522 m2/g and maximum pore volumes (up to 0.50 cm3/g), they possessed good thermal stabilities with the highest values (degradation temperature = 460 °C; char yield = 67 wt%). Furthermore, the produced polymers have been proven to have adsorption capability as well as photocatalytic degradation for both Rhodamine B (RhB) and methylene blue (MB) dyes. BC-TT CMP exhibited the highest adsorption efficiency among others toward the RhB dye with a capacity of 228.83 mg/g, as well as the maximum performance for MB dye uptake (up to 232.02 mg/g). After measuring the photocatalytic degradation of dyes using these CMPs, BC-TT-CMP also showed the top value of catalytic efficiency at all, either for RhB (rate constant: 2.5 × 10−2 min−1) or MB dye (rate constant: 3.5 × 10−2 min−1).