Recent advances in BixOyClz photocatalysts for photodegradation of active pharmaceutical ingredients: A critical review
Brahim Akhsassi, Abdelaziz Imgharn, S. Bikerchalen, L. Mllaoiy, B. Bakiz, Abdallah Albourine, A. Taoufyq, J.R. Gavarri, Laurent Ruhlmann, A. Benlhachemi
Abstract
Advanced oxidation processes are promising methods of degrading active pharmaceutical ingredients (APIs). The photocatalytic oxidation process is particularly useful in breaking down these persistent compounds. It is common for APIs to be resistant to conventional treatment, which contributes to long-lasting pharmaceutical pollution in wastewater and natural waters. This process generates reactive species capable of mineralizing organic pollutants by utilizing the semiconductor materials' merits. Unlike conventional photocatalysts, such as TiO 2 and ZnO, which are especially susceptible to UV light and are prone to stability problems, bismuth oxyhalides (Bi x O y X z , X = Br, Cl, I) materials show much improved photocatalytic performance under solar light. In particular, the bismuth-rich bismuth oxychlorides (Bi x O y Cl z ): Bi 3 O 4 Cl, Bi 24 O 31 Cl 10 , Bi 12 O 17 Cl 2 , and Bi 12 O 15 Cl 6 exhibited enhanced photocatalytic activities for APIs decomposition under visible light illumination. This enhanced activity is largely attributed to their capacity for high charge carrier separation. This comprehensive review outlines current advances in the development of Bi x O y Cl z -based photocatalysts for the degradation of pharmaceutical pollutants. Starting with the fundamentals of photocatalysis, it then discusses in detail the structural and electronic properties that make Bi x O y Cl z semiconductors effective under visible light. Advances in methods for synthesizing bismuth oxychloride-based materials are then explored, with particular attention to how these techniques influence photocatalytic performance. Key strategies used to enhance activity, including heterojunction formation, doping and surface engineering, are also reviewed. Finally, current challenges and future prospects are discussed, with an emphasis on real-world applicability and the potential integration of Bi x O y Cl z photocatalysts into wastewater treatment systems.