Degradation of acetamiprid in UV/H2O2 and UV/persulfate systems: A comparative study

Acetamiprid (ACE) was degraded by using ultraviolet (UV) irradiation and UV based advanced oxidation processes (AOPs) including UV/hydrogen peroxide (UV/H2O2) and UV/potassium persulfate (UV/PS). Among them, UV/PS process exhibited the best performance for the elimination of ACE and reduction of total organic carbon (TOC). The degradation kinetics was comprehensively compared in terms of dose of oxidants, solution pH, and water matrix species. A linear relationship was tentatively developed between the [Oxidant]/[ACE] ratio and the pseudo-first-order kinetic rate constant (k). The degradation was significantly inhibited at basic conditions no matter for UV/H2O2 process or UV/PS process. The effects induced by the water matrix species including inorganic anions and natural organic matter (NOM) were also non-negligible. For UV/PS process, both SO4 center dot - and HO center dot contributed to the ACE degradation, whereas only HO center dot participated in the degradation in the UV/H2O2 process. The corresponding second-order rate constants of ACE with HO center dot and SO4 center dot - were determined to be 7.59 x 10(8) and 3.68 x 10(8)M(-1) s(-1), respectively. Due to the different active radical species, different degradation products were detected through the HPLC-MS analysis. This work would be meaningful for the remediation of ACE from water by AOPs.