The filtration and degradation mechanism of toluene via microwave thermo-catalysis ceramic membrane

A series of ceramic membranes for toluene filtration and degradation were prepared by impregnation. The filtration and degradation of gaseous toluene was investigated during microwave thermo-catalysis in the continuous flow mode. The results showed that the ceramic membranes with components of Cu, Mn, Ce oxides were active in the filtration and degradation of toluene. The active ingredients uniformly existed in spinel form of Cu, Mn and Ce oxides with different valence, and the load distribution was also correlated with its surface morphology and specific surface area. Under the optimal conditions of toluene concentration of 697 +/- 54 mg m(-3), gas flow rate of 200 mL min(-1) and microwave power of 500 W, the membrane with three loading times of active components showed excellent retaining property, catalytic activity and structural stability. After 10 consecutive cycles (2100 min in total), the maximum removal efficiency of toluene was 85%. Based on total volatile organic compounds (TVOC) analysis, removal efficiency of TVOC was maintained at 94%. Toxicity analysis indicated that most of the possible intermediate products generated in the degradation process had relatively less impact on the environment than that of toluene. Results demonstrated a new way to design catalytic ceramic membranes that can retain and degrade VOCs during filtration and microwave thermo-catalysis process.