Toluene was decomposed in a surface-discharge plasma reactor and the combined effect of zeolite in the plasma reactor was studied. The decomposition of toluene and the product compositions depended on the reactor configuration and the capacity of zeolite to adsorb toluene. Toluene adsorbed on the zeolite (micro-pores) was not properly decomposed in the head of the plasma (P1), while it was readily decomposed not only in the tail of the plasma (P2) but also in the second reactor (P3) out of the plasma region because the oxidation of adsorbed toluene was enhanced by ozone as well as by atomic oxygen species derived from the plasma region. The synergistic effect of zeolite was attributed to its capacity to adsorb toluene and the cyclic plasma operation, which reduced the input energy. (c) 2005 Elsevier B.V. All rights reserved.