Catalytic wet oxidation of 2,4-dichlorophenol solutions: activity of the manganese-cerium composite catalyst and biodegradability of the effluent stream.
Aqueous solutions containing 100 to 1000 mg/L of 2,4-dichlorophenol (2,4-DCP) were oxidized in an upflowing fixed-bed reactor in this study of manganese-cerium composite catalysts, which were prepared by the coprecipitation of both manganese nitrate and ceric nitrate at various molar concentrations. Results showed that 2,4-DCP conversion by wet oxidation in the presence of the manganese-cerium composite catalysts was a function of the molar ratio of the manganese-cerium catalyst. The kinetic behavior of 2,4-DCP oxidation with catalysis could be explained by using a zero-order rate expression. Total organic carbon (TOC) removal by wet oxidation in the absence of any catalyst was nil, while approximately 68% TOC reduction was achieved during wet oxidation over a manganese-cerium (7:3 mol/mol) catalyst at 160 degrees C and an oxygen partial pressure of 1.0 MPa. Moreover, the 5-day biochemical oxygen demand/chemical oxygen demand ratios of all the effluent streams were determined to be greater than 0.45 as the wet catalytic processes were carried out at a liquid hourly space velocity less than 24 h (-1), indicating that they could be made more amenable to further biological treatment.
Lee
Bing-Nan
BN
Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan.
Lou
Jie-Chung
JC
Yen
Po-Chung
PC
D000465:Algorithms; D001673:Biodegradation, Environmental / Q000187:drug effects; D002244:Carbon / Q000378:metabolism; D002384:Catalysis / Q000187:drug effects; D002563:Cerium / Q000494:pharmacology; D002713:Chlorine / Q000494:pharmacology; D002733:Chlorophenols / Q000378:metabolism*; D004867:Equipment Design; D008345:Manganese / Q000494:pharmacology; D008954:Models, Biological; D010084:Oxidation-Reduction; D010100:Oxygen / Q000494:pharmacology*; D014865:Waste Disposal, Fluid / Q000379:methods*; D018508:Water Purification / Q000379:methods
D002733:Chlorophenols; D002563:Cerium; D008345:Manganese; D002713:Chlorine; D002244:Carbon; C004762:2,4-dichlorophenol; D010100:Oxygen