A Comprehensive Review of O ₂ /O ₃ Gas Separation

Ozone (O3) is widely used in water and air treatment, food industry, medical applications, and many others. However, ozone generation remains intrinsically energy-intensive, typically producing less than 15 wt.% O3 from oxygen-rich feed gases in conventional corona discharge systems. A promising strategy to address this challenge involves enriching the product stream with ozone by selectively separating unreacted oxygen (O2), which can be recirculated back to the generator, thus reducing the cost of O2 production. This work presents a comprehensive review of the main technologies available for O2/O3 gas separation, namely adsorption, cryogenic liquefaction, and membrane-based processes. For each approach, relevant scientific literature and patent developments are systematically analyzed, with emphasis on separation performance, material stability, energy requirements, scalability, and safety considerations. This review highlights current progress, key challenges, and future research directions in O2/O3 separation, emphasizing the need for improved material durability, higher selectivity, and process integration strategies.