NOx REMOVAL BY VACUUM ULTRA-VIOLET LIGHT IRRADIATION IN FLOW REACTORS

In this work, the photolysis of NO by irradiation with a 172 nm Xe2 excimer lamp was investigated in a perfectly mixed flow-through reactor (Continuous Stirred Tank Reactor, CSTR). The influence on the reaction rate of parameters such as the inlet flow, the substrate concentration, the photon flux entering into the reactor and the presence of oxygen was investigated. The experimental kinetic data were interpreted applying a general first-order kinetic model valid for CSTR, properly modified to take into account the changes in the experimental parameters. The pseudo first-order kinetic constant for the direct photolysis of NO under conditions of maximum irradiation was evaluated and the related reaction rate at different concentration computed. VUV photolysis of NO is a first-order process with respect to NO. The NO direct photolysis rate is linearly depended from the photon flux entering into the photo-reactor. In the presence of oxygen two different reaction pathways are operative suggesting the presence of indirect mechanisms of transformation in which O3 plays a key role. In the presence of O2 an almost complete abatement of NOX was observed.