Photocatalytic reactors: Technological status, opportunities, and challenges for development and industrial upscaling

Abstract The design, construction, and scale-up of photocatalytic reactors for large-scale industrial applications is still an open problem. Considering the technologic point of view, intensive efforts of research and development have been invested to help overcome different problems in bulk reactors such as photon transfer limitation, mass transfer limitation, oxygen deficiency, and lack of reaction pathway control. The approaches developed so far are limited. For this reason, it is necessary to explore alternative methodologies for designing novel photocatalytic reactors. This chapter focuses on the evaluation of the photocatalytic reactor's performance and is conceptually divided into two parts. The first part reviews the historical background of photocatalytic reactors, followed by an explanation of the current reactor's major problems. The second part is dedicated to exploring the opportunities and challenges for development and industrial upscaling. The chapter is intended for engineers, researchers, and advanced students who are involved in the study, design, and application of photocatalytic equipment/process for treatment purposes and could be a bridge to remove the gap between the theory and practical use of photocatalytic degradation technology.