Exploring heterogeneous catalytic ozonation: Catalyst types, reaction mechanisms, applications, challenges, and future outlook

Ozone (O 3 ) is a potent oxidizing agent that breaks down refractory organic contaminants (ROCs) into smaller, less hazardous molecules. In heterogeneous catalytic ozonation (HCO), O 3 is injected into the wastewater stream as a gas or as O 3 -enriched air. A solid catalyst improves ozonation efficiency by boosting O 3 breakdown and the production of reactive oxygen species (ROS) capable of oxidizing ROCs. Metal oxides (Me Os) are the often used catalysts. However, the kind of HCO catalyst used and how it reacts with O 3 determine how much ROS is produced. The production of ROS is encouraged by various HCO catalysts via various mechanisms, which may affect the HCO process's efficiency and selectivity. The kinds, mechanisms, and characteristics of the various HCO catalysts used are thoroughly examined in this study to provide a deeper understanding of the HCO process. In addition, parameters that need to be adjusted to improve degradation efficiency-such as pH and temperature are covered. The study ultimately expands on already published research to identify a variety of HCO applications while considering the viability of HCO in the form of pilot-scale and full-scale implementations, as well as real-world performance. HCO catalysts' challenges and promises for future water treatment are assessed. The goal of the current review is to provide academics and specialists with an overview of the application of HCO for ROC degradation. • O 3 is an oxidizing agent that breaks down refractory organic contaminants9ROCs). • Me Os are effective HCO catalysts • The •OH produced degrades the ROCs in wastewater via oxidation processes. • Operational parameters optimization for effectiveness ROC treatment. • MOFs and MOF-derived composites as HCO catalysts have catalytic ability.