Fabrication of a novel separation-free heterostructured photocatalyst with enhanced visible light activity in photocatalytic degradation of antibiotics

Abstract

A novel separation-free poly(N,N′-dimethylacrylamide)–titanium dioxide/copper sulfide (PDMAA–TiO₂/CuS) hydrogel photocatalyst with the synergistic effect of adsorption and photocatalysis has been successfully developed by a facile two-step method involving a homogeneous polymerization process and a chemical precipitation approach. The catalyst not only shows strong capability to adsorb organic pollutants, but also provides multidimensional quality and electron transfer channels owing to the formation of a heterojunction between TiO₂ and CuS nanoparticles as confirmed by TEM and PL spectra. Furthermore, the effects and mechanisms of adsorption and photodegradation of sulfaclozine as the target contaminant are investigated. The adsorption process of sulfaclozine on the composite hydrogel followed a pseudo-second-order rate equation and fitted in Langmuir monolayer adsorption. The photodegradation and mineralization of sulfaclozine reached 97.86% and 67.53%, respectively, when sulfaclozine degradation by the PDMAA–TiO₂/CuS hydrogel achieved balance within 22 h. The intermediates of sulfaclozine degradation are identified through HPLC-MS, and the sulfaclozine degradation pathway is proposed. Therefore, this work might provide new insights to develop environmentally friendly separation-free high efficiency catalysts for the degradation of organic contaminants.