Study of catalytic wet air oxidation to be used in the pretreatment of phenol wastewater

Compared with wet air oxidation,catalytic wet air oxidation has better effect on treating wastewater under mild conditions. Two kinds of catalyst are prepared:CuO/ η Al 2O 3 and AC catalysts. Firstly,the effect of these catalysts on catalytic wet air oxidation to be used in phenol wastewater treatment under different conditions is evaluated. The results show that raising pH value in the solution has disadvantageous effect on the removal of COD Cr from phenol wastewater. As to CuO/ η Al 2O 3 and AC catalysts, the COD Cr removal rate is higher under mild conditions:after 1 h reaction time, at 140 ℃,the COD Cr removal rate reaches 93.2% and 88.4% respectively;and at 160 ℃,the COD Cr removal rate reaches 93.4% and 90.1% respectively. But at 140 ℃,after the phenol wastewater is treated by wet air oxidation for 1 h, the BOD 5/COD Cr reaches only 0.08. The effect of different biodegradability is resulted from using different catalysts. BOD 5/COD Cr reaches 0.30 by using catalyst CuO/ η Al 2O 3,while BOD 5/COD Cr reaches 0.18 by using catalyst activated carbon as catalyst. Therefore using CuO/ η Al 2O 3 as catalyst to treat phenol wastewater can get the pretreatment effect under lower temperature.