Oxidation of bisphenol A by UV/S2O8(2-): comparison with UV/H2O2.

The UV/S2O8(2-) process was applied to decompose bisphenol A (BPA), which is a representative endocrine-disrupting chemical (EDC), and was comared with the UV/H2O2 process. The BPA degradation efficiency by UV/S2O8(2-) was increased by increasing S2O8(2-) concentration or decreasing BPA concentration. The presence of humic acid caused an inhibitory effect. The BPA oxidation rate by UV/S2O8(2-) was increased in the following order: neutral pH (pH(i) = 7) < acidic pH (pH(i) = 4) < basic pH (pH(i) = 10). The main oxidizing species in the UV/S2O8(2-) system was sulphate radical (SO4(-*)), whereas the main oxidizing species in the UV/H2O2 system was OH radical (OH*). Compared with UV/H2O2, the UV/S2O8(2-) process showed higher performance for not only BPA degradation but also its mineralization, which means that SO4(-*) is a more effective oxidant for BPA than the OH*. The results shown in this study imply that the SO4(-*) -based UV/S2O8(2-) process can be an excellent alternative process for the widely used UV/H2O2 process, with higher remediation performance.