Catalytic wet-air oxidation

The Catalytic Wet Air Oxidation (CWAO) process is capable of converting all organic contaminants ultimately to carbon dioxide and water, and can also remove oxidizable inorganic components such as cyanides and ammonia. The process uses air as the oxidant, which is mixed with the effluent and passed over a catalyst at elevated temperatures and pressures. If complete COD removal is not required, the air rate, temperature and pressure can be reduced, therefore reducing the operating cost. CWAO is particularly cost-effective for effluents that are highly concentrated... 

Beziat, J., Besson, M., and Gallezot, R, Catalytic wet air oxidation of wastewater, 3rd World Congress on Oxidation Catalysis, 1997, pp. 615-621. 

Pintar, A., Besson, M., Gallezot, P., Gibert, J.J. and Martin, D. (2004) Toxicity to Daphnia magna and Vibrio fischeri of Kraft bleach plant effluents treated by catalytic wet-air oxidation, Water Research... 

Polcaro, A.M., Mascia, M., Palmas, S. and Vacca, A. (2004) Electrochemical degradation of diuron and dichloroaniline at BDD electrode. Electrochim. Acta, 49,649-656 Polcaro, A.M., Vacca, A., Mascia, M. and Palmas, S. (2005) Oxidation at boron doped diamond electrodes An effective method to mineralise triazines. Electrochim. Acta 50,1841-1847 Posada, D., Betancourt, P., Liendo, F. and Brito, J.L. (2006) Catalytic wet air oxidation of aqueous solutions of substituted phenols. Catal. Lett. 106, 81-88 Rajeshwar, K. and Ibanez, J. (1997) Fundamentals and Applications in Pollution Abatement, Academic, New York, NY... 

Suarez-Ojeda, M.E., Stuber, F., Fortuny, A., Fabregat, A., Carrera, J. and Font, J. (2005) Catalytic wet air oxidation of substituted phenols using activated carbon as catalyst. Appl. Catal. B Environ. 58,105-114... 

Specific Applications The tables show several specific reactions for which monoliths have been tested. Two topics that recently have received considerable attention are Fischer-Tropsch synthesis and catalytic wet air oxidation. Details follow. 

Nippon Shokubai developed a process for catalytic wet air oxidation and implemented it in at least 10 industrial plants in Japan and elsewhere 152,214). As reported by Liick 152), the Nippon Shokubai process involves a Pt-Pd/Ti02-Zr02 honeycomb catalyst that is not sensitive to deposition of solids on the catalytic surface. Typical operating conditions of the process are a temperature of 493 K, a pressure of 4 MPa, and a space velocity of 2 h (153). It has not been disclosed beyond any doubt whether monoliths are indeed applied in these processes. 

F. Luck, M. Djafer, and M.M. Bourbigot, Catalytic wet air oxidation of biosolids in a monolithic reactor. Proceedings of the European Symposium on Catalysis in Multiphase Reactors, Lyon, France, 7-9 December 1994. 

Catalytic wet air oxidation (WAO) is an attractive process for the purification of industrial waste waters containing a small amount of organic pollutants. It involves the total oxidation of dissolved organics to carbon dioxide and water (or at least a transformation into biodegradable molecules). 

Precious metals (Pt, Pd, Ru) deposited on supports have been reported to be active for catalytic wet air oxidation (CWAO). Gallezot et al [9] have shown that platinum catalysts supported on carbon could decompose formic, oxalic and maleic acids very easily, at... 

Heterogeneous catalysts systems are known to be promising for wastewaters treatments. The development of active and stable heterogeneous catalysts has received thus a great attention. In this light, the efficiency of several noble metals including (Pt, Pd, Ru, Rh..) for the catalytic wet air oxidation (CWAO) of various organics pollutants has been demonstrated [1]. For oxidation of acetic acid, ruthenium was one of the most active metals as underlined by... 

Environmental applications of metal-doped carbon gels can be divided between reactions carried out in the gas and aqueous phases. The former group includes volatile organic compound (VOC) oxidation (e.g., toluene and xylene oxidation) and NO reduction. The latter group includes the catalytic wet air oxidation (CWAO) of aniline solutions and advanced oxidation processes (AOPs) (e.g., catalytic ozonation and photooxidation of pollutants). 

Gallezot P., Chaumet S., Perrard A. and Isnard P. 1997. Catalytic wet air oxidation of acetic acid on carbon-supported rutheniiun catalysts, J. Catal., 168, 104—109. 

Beziat J.-C., Besson M., Gallezot P. and Durecu S. 1999. Catalytic wet air oxidation of carboxyhc acids on TiOj supported rutheniimi catalysts, J. Catal., 182, 129-135. 

Pintar A., Besson M. and Gallezot P. 2001. Catalytic wet air oxidation of Kraft bleaching plant effluents in the presence of titania and zirconia supported ruthenium, Appl. Catal. B, 30, 123-139. 

Eftaxias A., Font J., Fortuny A., Giralt J., Fabregat A. and Stiiber F. 2001. Kinetic modeling of catalytic wet air oxidation of phenol by simulated annehng, Appl. Catal. B, 33, 175-190. 

Vospernik, M., Pintar, A., Levee, X, 2006. Application of a catalytic membrane reactor to catalytic wet air oxidation of formic add. Chemical Engineering and Processing Process Intensification 45,404 14. 

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