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

• Published in: Industrial & engineering chemistry research 1999-05, Vol.38 (5), p.1754-1758
• Main Authors: Nogueira, Raquel F. P, Alberici, Rosana M, Mendes, Maria Anita, Jardim, Wilson F, Eberlin, Marcos N
• Format: Article
• Language: English
• Subjects: Applied sciences; Chemistry; Exact sciences and technology; General and physical chemistry; General purification processes; Photochemistry; Physical chemistry of induced reactions (with radiations, particles and ultrasonics); Pollution; Wastewaters; Water treatment and pollution
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/ie980497+

Membrane introduction mass spectrometry (MIMS) has been applied to monitor and compare in real time the extent by which three photocatalytic remediation processesFenton's reagent/UV, ferrioxalate/H2O2/UV, and TiO2/UVdestroy two common water pollutantsphenol 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.