Noble metals supported on carbon black composites as catalysts for the wet-air oxidation of phenol

摘要

Pt, Pd and Ru catalysts supported on carbon black composites (CBC) were characterized in the wet air oxidation of phenol solution using a fixed-bed reactor working in a trickle-flow regime under relatively mild conditions: temperature, 393-433 K; pressure, 50-80 bar; liquid hourly space velocity (LHSV), 0.5-6 h~(-1). The activity of the catalysts decreases in the following order: Pt/CBC > Pd/CBC approx= Ru/CBC CBC. The physicochemical properties of the CBC are affected by its reaction with oxygen during the oxidation process. Combustion of the CBC material in the aqueous phase proceeds at a lower temperature than that in the gas phase; its surface properties change according the same rules as during low temperature oxidation by gaseous air.