Effect of Anions and Cations on Tartrazine Removal by the Zero-Valent Iron/Peroxymonosulfate Process: Efficiency and Major Radicals

Zero-valent iron/peroxymonosulfate (Fe-0/PMS) has been considered as a promising approach for wastewater treatment. Anions and cations are widely present in wastewater and have significant effects on the performance of the Fe-0/PMS system for wastewater treatment. Thus, in the present study, tartrazine was selected as the target model; SO42-, NO3-, HCO3-, and Cl- were selected as representative anions and Ca2+, Cu2+, Mg2+, and Mn2+ were chosen as representative cations. The effect of these anions and cations on tartrazine removal and major radicals in the Fe-0/PMS were systematically investigated. The presence of a certain concentration of SO42- and Cl- had positive, NO3- had negative, and HCO3- had negligible effects on tartrazine removal in the Fe-0/PMS system. SO42- and HCO3- had a small effect on the contribution proportion of reduction, SO4 center dot- and (OH)-O-center dot; a certain concentration of Cl- could enhance the contribution proportion of (OH)-O-center dot; and NO3- would decrease the contribution proportion of SO4 center dot- and (OH)-O-center dot. A certain concentration of each of Ca2+, Cu2+, Mg2+, and Mn2+ could enhance the tartrazine removal in the Fe-0/PMS system. Ca2+, Cu2+, and Mg2+ had no effect of the contribution of reduction, SO4 center dot- and (OH)-O-center dot, while a certain concentration of Mn2+ could enhance the contribution proportion of SO4 center dot-. These results can provide some references for the Fe-0/PMS system to treat actual wastewater containing anions and cations.

Automated summary

Zero-valent iron/peroxymonosulfate (Fe-0/PMS) has been studied for its potential in wastewater treatment. Anions and cations have significant effects on the performance of Fe-0/PMS system. This study investigated the influence of various anions and cations on tartrazine removal in the Fe-0/PMS system, and found that certain anions and cations can enhance the removal efficiency.