Abstract 

Water treatment is a worldwide environmental challenge because of the complexity in terms of the quality and nature of pollutants discharged in different wastewaters. Following the circular economy aspects, developing green routes and natural resources to run all industrial processing is highly recommended. Photocatalytic technology has been studied over decades as an alternative route toward wastewater purification. In the belief that natural solar light can be exploited to drive photocatalytic water treatment, a large pool of research studies was reported to understand this technology’s fundamental basis and technological factors in creating opportunities for real-world use. This chapter discusses the photocatalytic oxidative technology for water treatment by emphasizing fundamental research and technical issues. In order to elucidate the potential incorporation of photocatalysis within wastewater treatment stations (WWTPs), the initial section expounds upon the prevailing paradigm of centralized WWTPs and the method by which technologies are meticulously chosen to cater to specific requirements. The principle of photocatalysis and how reactive oxygen species are produced on the surface of the photocatalyst are discussed. The most common approaches to enhance the performance of photocatalytic technology are systematically discussed. The modes of photocatalytic applications such as suspension, supported, magnetic, and floating are explained, stressing the cons and pros of each. A history of photoreactor design and common types are briefly discussed. The final section provides an overview of reported photocatalytic water treatment patents, followed by a SWOT analysis to narrow the gap between research studies and extensive scale applications.