A new type of contactor is proposed for the combustion of Volatile Organic Compounds (VOCs) in diluted streams. This is based on the use of Pt/gamma-Al2O3 catalytic ceramic membranes operating in the Knudsen diffusion regime, which gives a highly efficient contact between the reactant feedstream and the catalytic material on the membrane. Essentially, complete combustion of toluene (used as an example of VOCs) in the range 100 to 5100 ppm was achieved at temperatures between 150 and 206 degrees C, using superficial velocities between 3 and 7.5 m/h.