Novel K-doped Mn-Ce-O wet oxidation catalysts with enhanced stability

The catalytic wet oxidation of aqueous phenol over Mn-Ce-O mixed oxide cata lysts was shown to be accompanied by undesirable formation of heavy polymer s on the catalyst surface, leading to severe loss in catalytic activity and in mineralization selectivity. New potassium-doped Mn-Ce-O mixed oxide cat alysts were developed and benchmarked for the destruction of concentrated p henolic (10(3) ppm) synthetic wastewater at very mild conditions (110 degre esC and 0.5 h/Pa O-2 pressure). Remarkable improvements in mineralization s electivity were attained. Complete removal of total organic pollution was a chieved within 10-20 min and mineralization selectivity exceeding 95% was a ttained over fresh K-Mn-Ce-O catalyst. The leach-proof ability of the catal yst was confirmed from analysis of the treated waters. Detailed characteriz ation of fresh and spent K-doped catalysts revealed drastic reduction in ca rbonaceous deposits on the catalyst surface, even after successive runs of non-regenerated catalyst samples. The catalyst surface was found to be acti ve after the catalyst was reused thrice, though this time the TPO-detected surface carbonaceous species were far less than those in the nonpromoted Mn -Ce-O catalyst. (C) 2001 Academic Press.