Ozone (O3) is often used in water treatment because of its high oxidation activity with the contaminants (Gucheng et al. 2017). In the ozonation process, two different pathways are followed: (i) direct reaction with O3 and (ii) indirect reactions with hydroxyl radicals. According to Mansouri et al. (2019), the AOPs which are effective for the oxidation and mineralization of a broad range of contaminants from wastewater are ozonation, ultraviolet radiation and H2O2 based. AOPs like O3/H2O2 and O3/AC are effective for DEP degradation when compared to the traditional methods (O3 and UV alone) (Medellin-Castillo et al. 2013). On performing the three different ozonation processes (ozone alone, O3/H2O2 and O3/ZnO) for DEP mineralization, O3/H2O2 showed better results (Wen et al. 2011). O3 and UV/O3 effectively reduced DEHP as compared to the conventional UV method, where pH plays an important role in the degradation process (Yang & Lin 2012). Whereas in a study for DMP degradation, UV/O3 process performs better than the free O3 process (Yang et al. 2020a, 2020b). AOPs such as UV/H2O2 were effective in alkaline conditions with natural organic matter (NOM) for DBP degradation (Wang et al. 2016a, 2016b). Table 6 depicts the list of ozone/UV-based AOPs for phthalate degradation showing the radicals generated and the removal efficiency of the process.
Ultraviolet/ozone-based AOPs for phthalate degradation
| Phthalate | Catalyst/process | Removal efficiency (%) | Radicals generated | References |
|---|---|---|---|---|
| DMP | (Cu2O)0.5·CuO·Fe2O3 nanoparticles (CFO NPs) | 100 (20 min) | •OH, •CH3 and  radicals | Liu et al. (2019) |
| Co-Mn-Mesoporous siliceous (MCM-41) catalyst | 99.7 (15 min) | •OH radicals | Tang et al. (2017) | |
| Cerium-loaded SBA-15 (Ce/SBA-15) | 88.7 (60 min) | •OH radicals | Yan et al. (2013) | |
| DEP | Electro-peroxone with carbon – polytetrafluorethylene | 99 (60 min) | •OH radicals | Hou et al. (2016) |
| DBP | Magnetic porous ferro spinel NiFe2O4 | 100 (60 min) |  and O2 radicals | Ren et al. (2012) |
| O3/UV process | 100 (60 min) | H2O and CO2 | Wang et al. (2013a, 2013b) | |
| BBP | O3/UV process with scavenger | 91 (15 min) | Tert butanol as radical scavenger | Lovato et al. (2014) |
| DEHP | V2O5/TiO2 – Ozone | 58.7 (1 min) | •OH radicals | Tak et al. (2022) |
| Phthalate | Catalyst/process | Removal efficiency (%) | Radicals generated | References |
|---|---|---|---|---|
| DMP | (Cu2O)0.5·CuO·Fe2O3 nanoparticles (CFO NPs) | 100 (20 min) | •OH, •CH3 and radicals | Liu et al. (2019) |
| Co-Mn-Mesoporous siliceous (MCM-41) catalyst | 99.7 (15 min) | •OH radicals | Tang et al. (2017) | |
| Cerium-loaded SBA-15 (Ce/SBA-15) | 88.7 (60 min) | •OH radicals | Yan et al. (2013) | |
| DEP | Electro-peroxone with carbon – polytetrafluorethylene | 99 (60 min) | •OH radicals | Hou et al. (2016) |
| DBP | Magnetic porous ferro spinel NiFe2O4 | 100 (60 min) | and O2 radicals | Ren et al. (2012) |
| O3/UV process | 100 (60 min) | H2O and CO2 | Wang et al. (2013a, 2013b) | |
| BBP | O3/UV process with scavenger | 91 (15 min) | Tert butanol as radical scavenger | Lovato et al. (2014) |
| DEHP | V2O5/TiO2 – Ozone | 58.7 (1 min) | •OH radicals | Tak et al. (2022) |