UV-metal ion synergistic activation of ferrate(VI) for the degradation of dimethoate

The improvement in the degradation efficiency of dimethoate was achieved through the activation of UV light and metal ions . The study found that Fe(VI) was effectively activated by Cu(II), Fe(III), and Fe(II), resulting in an improved removal rate of dimethoate in water, with the activation efficiency of Cu(II) > Fe(III) > Fe(II). Under UV irradiation , the synergistic activation effects of UV-Cu(II) and UV-Fe(III) were most pronounced and positively correlated with light intensity. The mineralization rate of dimethoate by UV-Fe(III)-Fe(VI) reached up to 37 %, significantly outperforming the Cu(II)-Fe(VI) system. The main active species in the Cu(II)-Fe(VI) and Fe(III)-Fe(VI) systems were Cu(III) and Fe(IV)/Fe(V), while those in the UV-Fe(III)-Fe(VI) were ·OH and ·O 2 - radicals, respectively. In the UV-metal ions activated Fe (VI) system, the main degradation mechanisms of dimethoate were hydrolysis, cleavage, oxidation , and recombination. The impacts of water quality parameters on degradation efficiency were also investigated, finding that Cl - had almost no effect , while SO 4 2- had a slight repression effect, and HCO 3 - , CO 3 2- and NO 2 - exhibited strong inhibitory effects. Finally, the promising application of the UV-metal ion-Fe(VI) system in actual water environments was proposed, achieving effective removal with minimal environmental risks.