- UV-LEDs assisted peroxymonosulfate/Fe2+ for oxidative removal of carmoisine: The effect of chloride ion
The performance of UVA-LEDs assisted peroxymonosulfate (PMS)/Fe2+ system was evaluated on carmoisine (E122) decolorization. Complete color removal was obtained under the conditions of pH=3.0, PMS=1.5mM, Fe2+=1mM and 25 min reaction time. UVA-LEDs were preferable compared to conventional UVA lamp in terms of decolorization. The functions of Co2+, Cu2+, Mn2+ and Fe2+ were compared and their results showed that Co2+ and Fe2+ had the highest efficiencies. Moreover, the presence of chloride ion showed a double role in different concentrations in which promotional effect was observed in 100mM Cl-<, while inhibitory effect occurred in 1-10mM Cl-. However, the high concentration of chloride had no influence on mineralization of E122. The scavenging results demonstrated that the UV irradiation increased the contribution of HO°. In addition, in the presence of chloride ion, HOCl along with sulfate and hydroxyl radicals were the major oxidative agents.