The mechanisms and process of acephate degradation by hydroxyl radical and hydrated electron

The degradation process of acephate in aqueous solution with OH and eaq− produced by 60Co-γ irradiation and electron pulse radiolysis was studied in the present paper. In the aqueous solution, acephate reacted with eaq− and transformed to transient species which can absorb weakly in the wavelength range of 300-400 nm and decay very fast. According to the decay of hydrated electron, the reaction rate constant of eaq− and acephate is (3.51 ± 0.076) × 109 dm3·mol−1·s−1. The transient species produced in the reaction of OH and acephate do not distinctly absorb the light in the wavelength range of 300-700 nm, so the decay and kinetics of the transient species cannot determinedirectly. The competing reaction of KSCN oracephate with OH were studied to obtain the reaction rate constant of OH and acephate, which is (9.1 ± 0.11) × 108 dm3·mol−1·s−1. Although acetylamide and inorganic ions were determined in the products of the reaction of acephate with OH or eaq−, the concentration of inorganic ions in the products of the reaction of acephate with OH is higher than that in the product of the reaction of acephate with eaq−. Moreover, there were sulfide in the products of the reaction of acephatewith eaq−. The degradation pathways of acephate by OH and eaq− were also proposed based on the products from GC-MS.