Nomex (TM) rejects-based activated carbon fibre composites, recently developed at our laboratory, were tested as catalytic supports for the low-temperature selective catalytic reduction (SCR) of nitric oxide with ammonia. Impregnation of the support was performed by equilibrium adsorption of a diluted aqueous solution of manganese acetate. Prior to impregnation, different pre-conditioning procedures of the carbonaceous support were investigated. These comprised steam activation and oxidation with air and different liquids. The modified supports were characterised by different techniques and the impregnated catalysts were tested for SCR of NO at 150 degreesC. The best catalytic results were achieved after support activation at 20 wt.% (S-BET approximate to 1000 m(2) g(-1)) and oxidation with nitric acid at 90 degreesC for 1-2 h.