Solid catalysts for wet oxidation of nitrogen-containing organic compounds

Several solid catalysts (Co3O4/gamma-Al2O3, Fe2O3/gamma-Al2O3, Mn2O3/gamma-Al2O3, Zn-Fe-Mn-Al-O, Pt/gamma-Al2O3, Ru/CeO2, Ru/C) have been prepared and used to remove N-containing organic contaminants while processing toxic and hazardous industrial waste waters using wet oxidation by air (WAO). The autoclave tests of catalysts were done to reveal the main advantages of catalysts in water presence at high pressures and temperatures. Catalyst activity was determined with regard to oxygen interaction with model mixtures (water-organic contaminant: acetonitrile, carbamide, dimethyl formamide, or multicomponent mixture of aliphatic alcohols). Activity tests were done in a static reactor under ideal mixing regime. Reagents and products were monitored using gas chromatograph Cvet-560, Millichrom-1 HPLC, and routine chemical analysis. Optimum process conditions for the best catalyst (Ru/graphite-like carbon) are as follows: partial oxygen pressure - 1.0 MPa, temperature - 473-513 K. At 0.5-5.0 MPa total pressure and 433-523 K catalysts show high water-resistance and high activity level (residual content of toxic compounds is less than 1%, and no NOx and NH3 are detected). There are no legal restrictions on catalysts operation, since they are harmless to environment. (C) 1998 Elsevier Science B.V. All rights reserved.