Comparison of hydroxyl-radical-based advanced oxidation processes with sulfate radical-based advanced oxidation processes

The sulfate-radical-based advanced oxidation process (SR-AOP) is gaining more research attention in this decade. Many studies are evaluating the ability of SR-AOP to replace hydroxyl-radical-based advanced oxidation process (HR-AOP). Implementing SR-AOP as a water treatment technique could overcome the major limitations associated with HR-AOP, such as acidic pH requirement, and the interferences by environmental components. Nonetheless, the mineralization efficiency in SR-AOP is a concern. Thus, despite many studies published on pollutant degradation using SR-AOP, those are insufficient to state the practical viability. This article shed light on the different ways of activating persulfate /peroxymonosulfate/H2O2 to yield reactive radicals, comparing SR-AOP and HR-AOP, followed by a discussion on the combined treatment processes. Particular emphasis is given to the limitations associated with SR-AOP, that are taken into account to achieve efficient mineralization of pollutants.