Photodegradation of nitrobenzene (NB) using an excimer UV lamp at a wavelength of 172 nm is investigated. Experimental results show that high concentration nitrobenzene can be efficiently degraded with irradiation by excimer UV lamp, and confirm that degradation of nitrobenzene is more efficient by UV/H2O2 combination than UV only. In the case of using UV only, 60 min of treatment was found to be sufficient to degrade the major part of NB solution with a concentration of less than 4 mM. In the case of using the combination of UV/H2O2 with a H2O2 concentration of 7:1 molar ratio to NB, 4.07 mM NB solution drastically decreased to 0.41 mM. after treatment for only 20 min. Degradation intermediate products are identified by analyzing the degradation products with GC/HRMS and possible degradation pathways of nitrobenzene are suggested. (c) 2005 Elsevier B.V. All rights reserved.