Influence of the structural and surface characteristics of activated carbon on the catalytic decomposition of hydrogen peroxide

Abstract

[EN] Different activated carbon-supported Fe catalysts have been prepared and tested in 
\nCWPO of phenol. Three well characterized activated carbons and two iron precursors 
\n(iron nitrate and iron pentacarbonyl) have been used. The behavior of these catalysts 
\nin CWPO has been related with their porous structure, surface composition, in terms of 
\noxygen groups and Fe distribution onto the catalyst particles. The catalysts with a more 
\nuniform distribution of Fe showed a higher oxidation activity than the ones with an 
\ninternal (egg-yolk type) or external (egg-shell type) distribution. These last provoke a 
\nfaster decomposition of H2O2 mainly to O2, non-reactive at the mild reaction 
\ntemperature used (50º C). No significant differences were observed from the iron 
\nprecursors. Complete conversion of phenol and almost 80 % mineralization were 
\nobtained in less than 2 hours with the best catalyst. The residual by-products consisted 
\nin short-chain organic acids without significance in terms of toxicity. Fe leaching was 
\nobserved in all the cases which can be mainly attributed to the presence of oxalic acid 
\nas oxidation by-product, refractory to the CWPO process investigated. The intensity of 
\nFe leaching was related with the concentration of oxalic acid