Catalytic wet air oxidation of chlorophenols over supported ruthenium catalysts.
A series of noble metal (Pt, Pd, Ru) loaded zirconia catalysts were evaluated in the catalytic wet air oxidation (CWAO) of mono-chlorophenols (2-CP, 3-CP, 4-CP) under relatively mild reaction conditions. Among the investigated noble metals, Ru appeared to be the best to promote the CWAO of CPs as far as incipient-wetness impregnation was used to prepare all the catalysts. The position of the chlorine substitution on the aromatic ring was also shown to have a significant effect on the CP reactivity in the CWAO over 3wt.% Ru/ZrO(2). 2-CP was relatively easier to degradate compared to 3-CP and 4-CP. One reason could be the higher adsorption of 2-CP on the catalyst surface. Further investigations suggested that 3wt.% Ru/ZrO(2) is a very efficient catalyst in the CWAO of 2-CP as far as high 2-CP conversion and TOC abatement could still be reached at even lower temperature (393K) and lower total pressure (3MPa). Additionally, the conversion of 2-CP was demonstrated to increase with the initial pH of the 2-CP solution. The dechlorination reaction is promoted at higher pH. In all cases, the adsorption of the reactants and the reaction intermediates was shown to play a major role. All parameters that would control the molecule speciation in solution or the catalyst surface properties would have a key effect.
Li
Ning
N
Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), UMR 5256, CNRS / Université Claude Bernard Lyon 1, 2 Avenue Albert Einstein, 69626 Villeurbanne Cedex, France.
Descorme
Claude
C
Besson
Michèle
M
D000327:Adsorption; D000388:Air; D002384:Catalysis; D002733:Chlorophenols / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D010084:Oxidation-Reduction; D010165:Palladium / Q000737:chemistry; D010984:Platinum / Q000737:chemistry; D012428:Ruthenium / Q000737:chemistry*; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods; D015040:Zirconium / Q000737:chemistry*
D002733:Chlorophenols; D014874:Water Pollutants, Chemical; D010984:Platinum; D010165:Palladium; D012428:Ruthenium; D015040:Zirconium; C028541:zirconium oxide