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Impact of Lamp Choice and Hydrogen Peroxide Dose on Photodegradation of Nitrobenzene

Impact of Lamp Choice and Hydrogen Peroxide Dose on Photodegradation of Nitrobenzene

Jeff Bandy, Hilla Shemer, K.G. Linden
Published In: 
Journal of Environmental Engineering Science,  
January 2009

Nitrobenzene (NB) was spiked into buffered lab water at 5 mM, and direct UV and H2O2-assisted photodegradation were evaluated using both medium-pressure (MP) and low-pressure (LP) ultraviolet (UV) lamps over a range of UV fluences and H2O2 concentrations. MPUV light was found to directly photodegrade nitrobenzene more rapidly than LPUV light, and in both cases loss of NB without UV irradiation (‘‘dark loss’’) contributed to the degradation rates. Addition of H2O2 improved degradation kinetics, and both LP and MP lamps performed equally as well over industrially relevant hydrogen peroxide doses (1–25 ppm H2O2), resulting in a one-log reduction of NB after 300 mJ/cm2 and 25 ppm H2O2. Competition kinetics studies using para-chlorobenzoic acid (pCBA) and molinate as probe compounds were performed to quantify the rate of reaction between target analytes [including NB and three nitrophenol isomers (NPs)] and hydroxyl radicals. Bimolecular rate constants could be used to accurately predict the NB degradation observed in this study. This work helps to clarify the quantum yield for the UV photodegradation of nitrobenzene and reports on the feasibility of utilizing a UV-based oxidation process to destroy a US EPA Contaminant Candidate List chemical of concern.

Bandy, J.C., Shemer H., Linden, K.G. “Impact of Lamp Choice and H2O2 Dose on Photodegradation of Nitrobenzene.” Journal of Environmental Engineering Science 26 (5): 973-980, 2009.