Zero-valent iron (ZVI) activation of persulfate (PS) for oxidation of bentazon in water

Generally, lower BTZ concentration, lower pH and higher temperature favored the treatment. Different coexisting ions exhibited different effects. Al3+, Cl− and NO3− improved the treatment; NH4+, Ca2+, and Mg2+ did not significantly influence the BTZ removal; and, Mn2+, Cu2+, CO32−, HCO3−, PO43−, HPO42− and H2PO4− inhibited the BTZ degradation. Most of BTZ were not mineralized, and instead degraded into three major degradation products including 2,1,3-benzothiadiazin-4(3H)-one-2,2-dioxide (P1, C7H6N2O3S), 2-aminobenzoic acid (anthranilic acid) (P3, C7H7NO2), and 2-amino-2-sulfobenzoic acid (P5, C7H7NO5S). This study demonstrates that ZVI/PS is a viable alternative for controlling BTZ-induced water pollution.