Preparation Of Carbon Supported Metallic Catalysts For And Microwave Assisted Catalytic Wet Oxidation Of P-nitrophenol In Aqueous Solution Under Low Pressure

Wet air oxidation (WAO) is a promising method for the treatment of heavilycontaminated wastewater. However, severe operation conditions (high pressure and hightemperature) in WAO limit its wide application.In these studies, a novel reactor, microwave reactor under low pressure, was applied todegrade p-nitrophenol (PNP) in aqueous solution in the presence of activated carbon andcarbon supported metals used as catalyst.Carbon-supported metal catalysts (Pt/GAC, Cu/GAC, Mn/GAC, Fe/GAC) were preparedby using microwave energy. Metallic particles characterized by scanning electron microscopyand X-ray diffraction were small, and dispersed uniformly on the surface of GAC carrier. Asreductant, GAC reacted with metallic oxide in the process of catalyst preparation bymicrowave method with no need to use hydrogen reduction.Microwave reactor under low pressure was applied to degrade p-nitrophenol (PNP) inaqueous solution in the presence of Cu loaded on activated carbon (Cu/GAC) used as catalyst.The results showed that PNP could be effectively decomposed in this reactor. 83.2% of CODin the solution was removed after 30 min treatment under the conditions of 660 W ofmicrowave power, 1.2 MPa of oxygen pressure, 6 g of Cu/GAC. The removal efficiency wasrelated with catalyst dosage, microwave power, oxygen pressure and pH in the solution.BOD₅/COD_Cr in the solution treated increased from 0.107 to 0.376, which indicated that thebiodegradability increased greatly. The decomposition of PNP could be confirmed by thespectra of UV-Vis absorption. And the Cu/GAC was still stable after being used six times.In the presence of activated carbon and carbon supported metals (Pt/GAC, Cu/GAC,Mn/GAC, Fe/GAC) used as catalyst, PNP could be effectively decomposed in this reactor and85.8%, 83.2%, 80.9% and 70.1% of COD in the solution was removed, respectively, after 30min treatment under the conditions of 660 W of microwave power, 1.2 MPa of oxygenpressure, 6 g of catalysts. BOD₅/COD_Cr in the solution treated increased from 0.107 to 0.385,0.376 and 0.312, which indicated that the biodegradability increased greatly. Oxidation andagglomeration occurred on the surface of iron, copper and manganese particles. While noblemetal, platinum, has a good stability in experiments...