Fabrication of dual-function Nanofilm incorporating hydrophobic conjugated main chains and hydrophilic side chains for water purification with adsorption/catalysis capabilities

Abstract

The removal of low-concentration pollutants from wastewater often depends on conventional porous adsorbents. However, disposing of these adsorbents as hazardous waste may result in secondary contamination. In this study, a new method to construct adsorption/catalytic bifunctional materials from donor-acceptor (D-A) type polyelectrolyte material using self-assembly and freeze-drying techniques was proposed. The material comprises a conjugated main chain, formed by the alternating copolymerization of electron-donating fluorene and electron-withdrawing benzothiadiazole, and a flexible carbon side chain terminated with an ammonium ion. Results found that the material could be constructed into a large-scale nanofilm using solvent-induced self-assembly followed by freeze-drying. The Nanofilm exhibited a rapid adsorption capacity of 374.53 mg g⁻¹ for bisphenol A (BPA) within 3 min. Density functional theory (DFT) calculations and experimental results indicate that the rapid adsorption is facilitated by electrostatic and hydrogen-bonding interactions between the catalyst and BPA, along with π-π interactions. The alternating D-A structure of Nanofilm efficiently improves the separation of photogenerated carriers and photodegrades 50 ppm BPA in 40 min with high efficiency. This adsorption/catalysis dual-function Nanofilm presents a novel and effective solution for the continuous and efficient purification of BPA.