Triphenylamine-linked triazine (D-A) units based hypercrosslinked porous polymer: Rapid adsorption and enhanced photodegradation of organic dyes from water

Abstract

Pigments and dyes are prevalent water contaminants, necessitating effective treatment methods. Hypercrosslinked porous polymers (HPPs), known for their high surface area and abundant micropores, effectively adsorb dye molecules and facilitate their degradation under light, making them a highly attractive solution. Herein, we synthesized donor-acceptor (DA) based TPA-TAZ HPP through Friedel−Crafts polymerization of triphenylamine as a donor and 2,4,6-trichloro-1,3,5-triazine (TCT) as an acceptor for adsorption and photo-degradation of Rhodamine B (RhB) and methylene blue (MB). The resulting TPA-TAZ HPP exhibits an impressive surface area of 1823 m² g^–1, significant thermal stabilities (T_d5: 663 °C, T_d10: 674 °C, char yield: 75 wt%), and a small band gap of up to 2.04 eV. The porous framework, abundant adsorption sites, and electronegative characteristics of TPA-TAZ HPP enable it to achieve outstanding adsorption performance. It demonstrated removal efficiencies of nearly 99 % for both RhB and MB within 5 minutes, with remarkable adsorption capacities of up to 951 mg g^–1 for RhB and 858 mg g^–1 for MB at ambient temperature. Additionally, TPA-TAZ HPP exhibited exceptional photocatalytic degradation efficiencies, achieving up to 88 % for RhB and 96 % for MB, with reaction rate constants of 5.78 × 10 ^–2 min^–1 and 9.62 × 10^–2 min^–1, respectively. The superior performance of TPA-TAZ HPP can be attributed to its high surface area, small band gap, and donor-acceptor framework, which collectively facilitate efficient charge transfer, thereby enhancing both adsorption and photocatalytic degradation. Our findings suggest that this research could guide the effective design of donor–acceptor-based HPPs as promising photocatalysts for a wide range of photocatalytic applications.