Oxidative degradation of emerging micropollutant acesulfame in aqueous matrices by UVA-induced H2O2/Fe2+ and S2O82−/Fe2+ processes

- UVA light effectively induced the H2O2/Fe2+ and S2O82−/Fe2+ processes.
- ACE was 100% degraded at pH 3 by the UVA/H2O2/Fe2+ and UVA/S2O82−/Fe2+ systems.
- Mineralization of ACE was generally lower than degradation in all studied processes.
- Hydroxyl radical was proposed to be predominant in the UVA/S2O82−/Fe2+ system.
- Natural water matrices strongly affected the target compound degradation efficacy.

In the present study, UVA/H2O2/Fe2+ and UVA/S2O82−/Fe2+ processes were applied to degrade the artificial sweetener, acesulfame (ACE) in ultrapure water (UW), groundwater (GW), and secondary effluent (WW). The degradation time and mineralization of 75 μM of ACE determined the efficacy of the procedures. The results indicated that the UVA-induced H2O2/Fe2+ and S2O82−/Fe2+ systems are a promising alternative for the removal of ACE from different aqueous matrices as both studied processes completely degraded the target compound at an ACE/oxidant/Fe2+ molar ratio of 1/10/1 and pH 3. In the case of UVA-induced systems application without pH adjustment, the ACE decomposition was achieved only in ultrapure water. The maximum mineralization of ACE in ultrapure water by the UVA/H2O2/Fe2+ system (molar ratio of 1/10/1) at pH 3 resulted in residual TOC of 18.3%. The oxidative effectiveness of the UVA/S2O82−/Fe2+ system was proved to be mainly formed by the hydroxyl radicals. The obtained results indicate that UVA light can be successfully used for the oxidation of the studied artificial sweetener in various aqueous matrices with carefully adjusted process conditions.