UV-C Activation of Peroxides for Bisphenol A Removal from a Real Water Sample

The peroxides peracetic acid (PAA) and percarbonate (PC) are applied for UV-C-based advanced oxidation of the endocrine disrupting micropollutant bisphenol A (BPA; 2 mg L-1 = 8.76 mu m) in pure and tap water. Their performance is compared with the more conventional hydrogen peroxide (HP)- and persulfate (PS)-activated UV-C treatments. Acidic and neutral pH values, 4 and 7, result in faster BPA removals with HP- and PS-activated UV-C treatments, respectively, whereas higher BPA removal rates are obtained at acidic and alkaline pH values, 4 and 10, with the PC/UV-C and PAA/UV-C treatments, respectively. Increasing the peroxide concentrations enhances BPA removals with the exception of PC/UV-C treatment where an asymptotic removal rate is ultimately reached due to the inhibitory effect of increasing alkalinity. The order of total organic carbon (TOC) removal for the BPA-spiked tap water (TW) (TOC approximate to 5 mg L-1 with added BPA) is TOCPAA/UV-C (16%) < TOCPS/UV-C (24%) < TOCHP/UV-C (27%) < TOCPC/UV-C (35%). BPA removal is most negatively affected for the HP/UV-C processes, whereas the PC/UV-C process outperformed the other peroxide/UV-C treatments in terms of TOC removal due to the differences in the reactivity/selectivity of the in situ formed free radical types that may become important when working with real water. The originally low toxicity toward the marine photobacterium Vibrio fischeri and the freshwater crustacean Daphnia magna fluctuated during photochemical treatments.