Acetamiprid removal in wastewater by the low-temperature plasma using dielectric barrier discharge

• The effect of different parameters on acetamiprid degradation was studied.
• The degradation pathway of acetamiprid was deduced.
• The degradation products and intermediates were analyzed by HPLC–MS.
• The degradation mechanism of acetamiprid was investigated.

Degradation of acetamiprid in wastewater was studied in a dielectric barrier discharge (DBD) reactor. This reactor produces ultraviolet light and reactive species like ozone (O3) can be used for the treatment of wastewater. We examined the factors that could affect the degradation process, including the discharge power, and the initial concentrations of acetamiprid, and O3 which is generated by the DBD reactor. We also investigated the effect of adding Na2B4O7 as a radical scavenger to probe the role of hydroxyl radical in the reaction. The results indicated that acetamiprid could be removed from aqueous solution effectively and hydroxyl radicals played an important role during the degradation by the low temperature plasma. The degradation process of acetamiprid fits the first-order kinetics. The degradation efficiency was 83.48 percent at 200 min when the discharge power was 170 W and the initial acetamiprid concentration was 50 mg/L. The removal efficiency of acetamiprid decreased with the increasing concentration of Na2B4O7 because B4O72− is an excellent radical scavenger that inhibited the generation of OH during the DBD process. The removal efficiency of acetamiprid improved in the presence of O3. The main reason was that O3 can oxidize certain organic compounds directly or indirectly by generating hydroxyl radicals. The degradation products of acetamiprid were characterized qualitatively and quantitatively using high performance liquid chromatography, mass spectrometry and UV–vis spectroscopy.