An overview of TiO₂-based photocatalytic membrane reactors for water and wastewater treatments

Photocatalytic membrane reactors (PMRs), which coupled photocatalysts (PCs) with the membrane separation process has gained huge interest for the purification of water and wastewater treatments. Titanium dioxide (TiO₂) is the most commonly used material used for the preparation of photocatalytic membrane reactors owing to its exceptional properties such as low cost, less toxicity, and high chemical stability as well as high surface to volume ratio and quantum confinement effect. Because of the large surface area of TiO₂ nano powder, it proved ample active sites for the reactions and enhance the catalytic activity. This review provides details on recent developments on TiO₂-based photocatalytic membrane reactors (T-PMRs) used for water purification and wastewater treatments and in pharmaceuticals based on the types of membranes, fabrication methods, characterization, operational parameters influencing photocatalytic process, and applications of membranes in disinfection and in the removal of pollutants. Moreover, a short description of heterogeneous/homogeneous photocatalysis and configurations and designs of PMRs is also given. By applying the optimum operating parameters and new engineering approach on PMRs, the efficiency of T-PMRs for water purification and wastewater treatments can be enhanced. The future research and perspectives for water purification and waste water treatments using T-PMRs were also suggested.