[Combination process of microwave desorption-catalytic combustion for toluene treatment].

ABSTRACT

Using activated carbon as adsorbent, toluene waste gas was treated by adsorption process. After the adsorption process was completed, the adsorbent was desorbed by microwave irradiation; then Cu-Mn oxide composite catalysts were prepared by impregnation and the desorbed toluene gas was treated by catalytic combustion so as to completely purify the pollutant. The concentration of toluene was measured by gas chromatography (GC). The results indicated that it is feasible to add air to provide oxygen to the desorbed gas after the completion of the desorption process, in order to achieve the catalytic combustion; the ratio of desorbed gas and air was 1 1 (volume ratio), and the corresponding catalytic space velocity was 2.67 s(-1). Desorption temperature could affect the concentration of toluene in the desorption gas thereby affecting the catalytic combustion efficiency; the results indicated that 400 degrees C was an appropriate temperature for desorbing the activated carbon. When the catalytic combustion was kept at 300 degrees C, the final toluene treatment efficiency was higher than 90%, which was higher than 95% during the most time of the treatment process.