Advancing Photocatalytic Oxidation Process for Sustainable Treatment of Wastewater from Livestock Production: Current Breakthroughs and Key Challenges

Wastewater from livestock production is characterized by a complex composition, high pollutant load and the presence of emerging contaminants. These properties lead to critical challenges in conventional treatment processes, including excessive energy consumption, low treatment efficiency and incomplete pollutant removal. Photocatalytic oxidation is an advanced oxidation process that uses light energy to generate reactive oxygen species to degrade pollutants. It has gained significant attention due to its advantages of high efficiency, environmental friendliness and the ability to mineralize organic pollutants into water, carbon dioxide and other small molecules without consuming fossil energy. However, despite its potential, photocatalytic oxidation has not been widely applied in wastewater treatment. This is mainly due to the large band gap, low utilization of visible light and fast carrier recombination of photocatalyst. To address these issues, this paper comprehensively reviews the current technical developments of the photocatalytic oxidation process and suggests potentially productive future studies. Despite significant progress, several critical challenges remain to be addressed in photocatalytic material applications, including low visible light utilization, complex synthesis process, expensive material costs, poor practical performance and insufficient mechanism understanding. This review will help design high-efficiency visible-light-driven photocatalysts and promote the application of photocatalysts in the treatment of wastewater from livestock production.