Optimal temperatures for catalytic regeneration of activated carbon

Activated carbons impregnated with a mixture of copper(II), iron(III) and chromium(III) oxide catalysts were prepared in order to facilitate catalytic regeneration of AC saturated with phenols. The temperature ranges of phenol oxidation (T-p), carbon oxidation (T-c) and carbon burn-off were determined from DTA/TGA investigations in oxidizing and inert atmospheres. The impregnated catalyst facilitated phenol oxidation but also lowered the T-c of the AC. Catalytic regeneration can be conducted between T-p (220-240 degrees C) and T-c (320-370 degrees C). Catalytic regeneration of spent impregnated carbon, at 270 degrees C in flowing air, restored almost all of its initial adsorption capacity and specific surface area while in the absence of a catalyst the regeneration achieved was only 25-30%. The results obtained from the polythermic investigations (DTA/TGA) correlate well with those from the regeneration experiments and, therefore, may be used for determination of temperature conditions for catalytic regeneration of saturated carbons. (C) 1997 Elsevier Science Ltd.