APPLIED CHEMISTRY Photocatalytic Degradation of Phenol and Trichloroethylene: On-Line and Real-Time Monitoring via Membrane Introduction Mass Spectrometry

Membrane introduction mass spectrometry (MIMS) has been applied to monitor and compare in real time the extent by which three photocatalytic remediation processessFenton’s reagent/ UV, ferrioxalate/H2O2/UV, and TiO2/UVsdestroy two common water pollutantssphenol and trichloroethylene (TCE). Continuous MIMS and selected ion monitoring (MIMS-SIM) of both phenol and TCE degradation and CO2 production show first-order kinetics for the three processes. Phenol half-life times indicate that Fenton’s reagent/UV and ferrioxalate/H2O2/UV destroys phenol 10 times faster than TiO2/UV, that is, Fenton’s reagent/UV ≈ ferrioxalate/H2O2/UV . TiO2/UV. For TCE, half-life times for the three remediation processes are ordered as follows: ferrioxalate/H2O2/UV . Fenton’s reagent/UV > TiO2/UV. For phenol, the extent of mineralization measured via total organic carbon analysis was lower than the extent of degradation measured by MIMS-SIM; hence, for the three processes, the intermediate products of phenol photocatalytic degradation are slowly destroyed. For Fenton’s reagent/UV and ferrioxalate/H2O2/UV, GC/MS analysis detected pyrocatechol as the main intermediate of phenol degradation and p-benzoquinone for TiO2/UV.