TiO2 assisted photocatalysts for degradation of emerging organic pollutants in water and wastewater

Abstract

The occurrence of emerging organic pollutants (EOPs) in the aquatic environment originating from point and diffuse sources, has been the subject of global apprehension in the recent years. These groups of compounds include pharmaceuticals, industrial products/by-products, personal care products and pesticides, which demonstrated pseudo-persistence conduct, resistance to degradation and frequent entrance into the environment through wastewater. The effective removal of EOPs from industrial wastewater and sewage represents one strategic procedure that could diminish their intrinsic environmental impacts. For this purpose, the advanced oxidation treatment using heterogeneous photocatalysts under light irradiation is consistently argued to show potential as economically viable and commercially feasible technology. Remarkably, for the efficient degradation of EOPs, nanostructured titanium dioxide (TiO2) containing materials have been favoured because of their anticipated combination of unique electronic structure, impressive light absorption properties, prolonged excited-state lifetimes and enhanced charge transport features. This review first highlights the research efforts associated with the manifestation and toxicity of EOPs in the environment. Subsequently, the treatment technologies that have been utilized in the literature for the removal of EOPs from aqueous media are summarized. Background information on the fundamental principles of light-driven catalytic activity at the surface of semiconductors is also presented. Next, a systematic survey of the latest progress in the development of TiO2 photocatalystsfor the degradation of EOPs is elaborated. The contribution of TiO2 photocatalysis in hybrid advanced oxidation procedures is also discussed. Notwithstanding the scientific efforts toward the minimization of wastewater generation, specific waste conditioning, and important information regarding cost, and benefits, as well as the scale-up of the treatment procedure are required to complement the advanced oxidative processes (AOPs)