Low-temperature combustion of 2,4,6-trichlorophenol in catalytic wet oxidation with nanocasted Mn-Ce-oxide catalyst

The essentially complete mineralization (>95% total organic carbon elimination) of 2,4,6-trichlorophenol by a CWO is reported at a very mild operating conditions (120 degrees C, PO2 = 10 bar), with the use of a nanocasted Mn-Ce-oxide catalyst. This unique catalyst was prepared by fabrication of a thin nanometric layer of Mn-Ce oxides inside the tubular mesopores of SBA-15 silica using internal gelation of corresponding metal chlorides. Crystallization of this oxide layer at 700 degrees C, followed by removal of silica matrix, yielded a nanostructured mixed-oxide catalyst with surface area up to 3 16 m(2)/g. It demonstrated superior textural, structural, and surface oxygen properties compared with a reference co-precipitated bulk Mn-Ce-oxide catalyst. This is a result of reduction and equalization of the crystal size of both oxide-phases Mn2O3 and CeO2 at the level of 2-3 nm, providing the full availability of their surface for reacting molecules. The performance measured with the novel catalyst indicates a major improvement in the efficient application of CWO processes for complete purification of complex waste streams. (C) 2007 Elsevier Inc. All rights reserved.