Mineralization of pentafluorophenol using photo-Fenton processes

The mineralization of pentafluorophenol (C6F5OH) in water using UV-C light and Fe(II) sulfate/Fe(III) oxalate with H2O2 was examined to develop a technique to counteract persistent and bioaccumulative C6F5OH to harmless species. Photo-Fenton process led to efficient degradation of C6F5OH to fluoride ions and CO2. Compared with the Fe(II)sulfate photo-Fenton process, the Fe(III) oxalate process is more efficient. The effects of various experimental parameters such as pH, initial concentrations of H2O2, Fe2+, Fe3+, C6F5OH and airflow rate on photomineralization have been investigated. GC/MS analysis of solutions before complete mineralization (after 30 min of irradiation) reveals the formation of tetrafluorodihydroxybenzene, trifluorotrihydroxybenzene and tetrafluoroquinone as intermediates. The products have been identified by comparing the molecular ion and mass fragmentation peaks of the product with those reported in the GC/MS library. The optimum operating conditions for efficient mineralization are reported.