A novel two-stage fluidized-bed/fixed-bed catalytic system was developed for the treatment of benzaldehyde residue. The effects of reaction temperature, oxygen concentration, space velocity on the purification of benzaldehyde production residue were investigated. The effluent chemical oxygen demand (COD) was less than 70 mgO2/L and the COD removal efficiency was higher than 99.83% under our experimental condition (fluidized-bed and fixed-bed temperature of 300-400°C, the flow rate of residue of 10 mL/h and O2 excessive rate of 20). The volatile organic compounds (VOCs) of the outlet were not detected after the treatment. The high-efficiency performance of the process can last for at least 600 h in the stability experiment. It was also verified by gas chromatography-mass spectrometry (GC-MS) analysis that most organic pollutants in the residue were significantly removed after treatment. These results suggest that the two-stage fluidized-bed/fixed-bed catalytic system could be a promising technology for the dispose of chlorine-containing polymer organics in the chemical industry.
Keywords: Benzaldehyde residue; chemical oxygen demand (COD); fluidized-bed; removal efficiency.