Activated Carbon Supported Mn Catalyst Peparation And Its Application In Catalvtic Ozonation Of Wastewater

Catalytic ozonation technology is used for decomposing organic contaminants by ozone and hydroxyl radical reactions, along with the functions of decolorization, deodorization and disinfection. Under higher standards of wastewater discharge and reduction in ozone generating cost, the catalytic ozonation technology finds its way to be a promising advanced oxidation method for wastewater treatment. In this paper, activated carbon supported Mn(ACSM) catalyst was prepared by impregnation and calcination method for catalytic ozonation of wastewater. The performance of the catalyst was investigated on both laboratory and pilot scale.The research suggests that the ACSM catalyst can obviously improve the removal rate of potassium hydrogen phthalate (KHP) by ozonation obviously. The recipe of catalyst is optimized based on the parameters such as calcination temperature, calcination time, loading capacity, species of carrier and soaking time. The catalyst with best performance is loading 5% of Mn after impregnation in precursor solution for 6 h and then calcination at 400℃ for 3 h, presenting the removal rate of COD two times higher than that of the activated carbon catalyst in 90 min.The laboratory scale experiments show that hydroxyl radical plays a relatively important role in the ozonation of KHP with the help of ACSM catalyst, which is proved by the fact that the removal rate of COD is decreased by hydroxyl radical inhibitor. The radical reaction is affected by pH, and weak alkaline is beneficial to the catalytic ozonation. The removal rate of COD is doubled when phenol aqueous solution is treated by ozonation in the presence of ACSM catalyst compared with the activated carbon. The catalyst also shows strong activity in the ozonation of industrial wastewater.The performance of ACSM catalyst is investigated on pilot scale by the ozonation of effluent from a centralized wastewater treatment plant in an industrial park. The catalyst exhibits pretty good performance with the COD removal of 40- 55 mg/L, the mass ratio of ozone dosage to COD removal at 0.4-0.7, and a distinct drop of color index of wastewater from 32 to 4.In short, a kind of catalyst for ozonation was prepared by supporting Mn on activated carbon, and its high activity was confirmed in laboratory and pilot scale experiments. This work paves a way for ozonation technology integrated with ACSM catalyst application.