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The photochemical reaction kinetics and mechanism of bisphenol A (BPA) with potassium persulfate (K2S2O8) were investigated by using 266 nm laser flash photolysis and gas chromatography mass spectrum (GC-MS) technique. Sulfate radical (SO4•–), generated upon K2S2O8 photolysis, reacted with BPA with the overall rate constant of (1.61±0.15)×109 L mol-1 s-1, and two main reaction mechanisms were involved. One was addition channel to generate BPA–SO4•– adduct with a specific second-order rate constant of (1.09±0.15)×109 L mol-1s-1. Molecular oxygen was involved in the decay of the BPA–SO4•– adduct with a rate constant of (1.28±0.14)×108 L mol-1 s-1. Another channel was the formation of BPA’s phenoxyl radical, likely derived from a deprotonation of the cation radical (BPA•+) generated from single electron transfer reactions. The specific rate constant of BPA’s phenoxyl radical formation was determined to be (6.16±0.08)×108 L mol-1 s-1. The overall rate constant was in line with the sum of aforementioned two specific rate constants for two main reaction channels. By comparing these rate constants, it was indicated that SO4•– addition channel accounted for ~65% (1.09/1.61) to the overall reaction, and phenoxyl radical formation accounted for only ~35% (0.62/1.61). The transformation products of BPA were identified by using GC-MS including 4-isopropylphenol, 4-isopropenylphenol, and 2, 4-di-tert-butylphenol, and the reaction mechanism was proposed. These results may provide microscopic kinetics and mechanism information on BPA degradation using SO4•–-based advanced oxidation processes (AOPs).

he photochemical reactions between 1-naphthol (1-NP) and superoxide anion radical (O2•−) were investigated in detail by using 365 nm UV irradiation. The results showed that the conversion rate of 1-naphthol decreased with the increase of the initial concentration of 1-naphthol, while the raising pH and riboflavin concentration accelerated the photochemical reaction. The second-order reaction rate constant was estimated to be (3.64 ± 0.17) × 108 L mol−1 s−1. The major photolysis products identified by using gas chromatography-mass spectrum (GC-MS) were 1, 4-naphquinone and 2, 3-epoxyresin-2, 3-dihydro-1, 4-naphquinone, and their reaction pathways were also discussed. An atmospheric model showed that both bulk water reaction and heterogeneous surface reaction deserved attentions in atmospheric aqueous chemistry.