Solar-Light-Responsive Nanomaterials for the Photoelectrocatalytic Degradation of Stubborn Pollutants

Abstract

Due to the ever increasing demand for cleaner water, a remarkable focus has been on the use of nanomaterials in wastewater treatment application. Photoelectrocatalytic (PEC) degradation, an advanced oxidation process which combines light and electrical energy, has been identified as a suitable technique capable of achieving total mineralisation of recalcitrant organic pollutants in wastewater. PEC degradation is non-selective, environmentally friendly and possesses great efficiency. The efficiency of PEC degradation has been enhanced by fabricating the photoanodes on a nanoscale with distinct morphologies. These nanostructured photoanodes have been extensively used for the removal of pharmaceuticals, dyes and phenolic water from wastewater. In many cases, total degradation of the pollutants is achieved within 2 h with significant TOC removal. This review presents an overview of the remarkable success that has been recorded with the use of nanostructured photoanodes in PEC degradation in the presence of visible light. The techniques that are commonly employed to improve the solar light responsiveness of these photoanodes are well discussed. Additionally, the use of nanostructured photoanodes consisting of heterojunction in PEC degradation is also presented. It is our aim that this review will help researchers to make informed decisions regarding the use of nanomaterials in PEC water treatment.