Ozonation of 1,3,6-naphthalenetrisulphonic acid catalysed by activated carbon in aqueous phase

This paper presents experimental results of the ozonation of a model aromatic sulphonic compound, 1,3,6-naphthalenetrisulphonic acid (NTS), in the presence of different activated carbons with different physical and chemical surface properties. Carbons used were commercial activated carbons (Ceca AC40, Norit, Merck, Witco, Ceca GAC, Filtrasorb 400, Sorbo) with or without demineralisation pre-treatment. Carbon samples were texturally and chemically characterised using N2 adsorption isotherms, mercury porosimetry, pHPZC, selective neutralisation and elemental analysis. Results show that NTS was degraded by ozone at a faster rate in the presence of activated carbon, especially in the case of Sorbo, Ceca GAC and Norit carbons, which display catalytic activity, probably by enhancing ozone decomposition in aqueous phase in highly oxidative species. These catalytic properties seem to be favoured by both the basicity of the carbon surface and the higher macropore volume. Dissolved total organic carbon from the NTS degradation compounds was removed in the presence of activated carbon through both the catalytic activity of activated carbon to mineralise organic matter and the adsorption of these organic compounds on activated carbon.