Oxidation of industrial dyeing wastewater by supercritical water oxidation in transpiring-wall reactor.
Industrial dyeing wastewater was oxidized in supercritical water in a transpiring-wall reactor, using hydrogen peroxide as an oxidant. Experiments were performed at 595 to 704 K and 18 to 30 MPa, with an oxidant dosage ratio ranging from 0.6 to 2.0. A chemical oxygen demand (COD) removal of more than 98.4% was achieved at 704 K and 28 MPa, with a retention time less than 35 seconds, which increased with the temperature, pressure, and oxidant. A modified first-order rate expression was regressed from experimental data, taking into account the influence of induction time. The resulting pre-exponential factor, A, and activation energy, Ea, were 1.07 seconds(-1) and 12.12 kJ x mol(-1), respectively, while the reaction order for feed wastewater (based on COD) and oxidant were assumed to be 1 and 0, respectively. Gas chromatography/mass spectrometry analysis for effluents indicated that carbon dioxide, carbon monoxide, and nitrogen were the main reaction products, and phenol; benzenecarboxylic acid; 1, 2-benzenedicarboxylic acid; and isoquinoline were detected as intermediates.
Gong
Wei-Jin
WJ
School of Environmental Science & Engineering, Donghua University, Shanghai, China. hggwj@yahoo.com.cn
Li
Fang
F
Xi
Dan-Li
DL
D006861:Hydrogen Peroxide / Q000737:chemistry*; D007220:Industrial Waste; D007700:Kinetics; D016877:Oxidants / Q000737:chemistry*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D011312:Pressure; D013696:Temperature; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry; D014877:Water Pollution, Chemical / Q000517:prevention & control; D018508:Water Purification / Q000295:instrumentation* / Q000379:methods*
D007220:Industrial Waste; D016877:Oxidants; D014874:Water Pollutants, Chemical; D014867:Water; D006861:Hydrogen Peroxide; D010100:Oxygen