Towards alternative/complementary wastewater treatment: a review of the recent advancements in photoelectrocatalytic oxidation of sulfonamide antibiotics.

The occurrence of pharmaceutical compounds in the environment has continued to attract the attention of researchers and this has become the focus of many scientific research work as well as review articles. Sulfonamides have been detected in underground water, seawater, sediment, soil, drinking water, river water, animal manure, treated water effluent and reclaimed water because it is not completely oxidised by most methods used in wastewater treatment plants. Photoelectrocatalytic (PEC) oxidation has distinguished itself as an efficient technology for the abatement of organic pollutants. This review provides insight into recent advancements made in the PEC oxidation of sulfonamides. We carefully captured the progress made in the choice of photocatalysts, light sources, and electrode substrates used. In addition, we also reviewed the recent progress made in the area of heterojunction engineering as this offers a promising and highly efficient approach towards the abatement of sulfonamides. Furthermore, the performances of the commonly known hydroxyl radical PEC and the sulphate radical PEC processes were compared and discussed. An extensive discussion on different types of photoanodes (pristine and modified) and dual photoelectrode systems used for the PEC oxidation of sulfonamides is presented with concluding remarks as well as future perspectives. Overall, this review will furnish the scientific community with insight into highly efficient, cheap, energy-saving, and sustainable technologies to remediate water polluted with emerging pharmaceutical contaminants.