Ozone meets peroxides: A symphony of hybrid techniques in wastewater treatment

Ozone (O3), with its robust oxidation capability and eco-compatibility, boasts an oxidation potential of 2.07 eV, enhancing water purification and playing a key role in industrial treatment. However, challenges such as pollutant selectivity, low TOC removal, and byproduct formation hinder its widespread use. Combining O3 with H2O2 has proven effective in overcoming these limitations. Additionally, O3′s integration with various peroxides like sodium percarbonate (SPC), calcium peroxide (CaO2), peroxydisulfate (PDS), and peroxymonosulfate (PMS) is gaining attention. These technologies are categorized into: (i) Peroxide-accelerated O3 processes, such as O3/H2O2, O3/CaO2, and O3/SPC, which efficiently generate •OH radicals, and (ii) O3-activated peroxide processes like O3/PMS and UV/O3/PDS, producing radicals like SO4•-. This review details these technologies' synergistic mechanisms and advantages. We also examine the impact of different process parameters, such as pH, oxidant concentration, and natural organic matter (NOM), on these processes, addressing their limitations. Future research directions for these integrated systems are also proposed, highlighting their potential in advancing wastewater treatment technology. In summary, the constructed O3-peroxide hybrid technologies offer significant improvements in organic water treatment, as evidenced by our comprehensive analysis. This review lays the groundwork for future applications and ongoing refinement of these combined technologies, ensuring more effective and sustainable water treatment solutions.