Efficient Degradation of Acesulfame by Ozone/Peroxymonosulfate Advanced Oxidation Process

Abstract

Artificial sweeteners (ASWs), a class of emerging contaminants with good water solubility, have attracted much attention recently because of their wide use and negative impact on the aquatic environment and drinking water. Efficient technologies for removing ASWs are in urgent need. This study investigated degradation of typical ASW acesulfame by ozone-activated peroxymonosulfate process (O3/PMS) in prepared and real waters. O3/PMS can degrade >90% acesulfame in prepared water within 15 min at a low dosage of O3 (60 ± 5 µg∙min−1) and PMS (0.4 mM). Ozone, hydroxyl radical (HO•), and sulfate radical (SO4•−) were identified as contributors for ACE degradation and their contribution proportion was 27.1%, 25.4%, and 47.5% respectively. O3/PMS showed the best degradation performance at neutral pH and were sensitive to constituents such as chloride and natural organic matters. The qualitative analysis of degradation products confirmed the involvement of hydroxyl radical and sulfate radical and figured out that the active sites of ACE were the C=C bond, ether bond, and C-N bond. The electrical energy per order ACE degradation were calculated to be 4.6 kWh/m3. Our findings indicate that O3 is an efficient PMS activator and O3/PMS is promising due to its characteristic of tunable O3−HO• SO4•− ternary oxidant involving.