Effects of sodium modification, different reductants and SO(2) on NO reduction by Rh/Al(2)O(3) catalysts at excess O(2) conditions.

Although many catalysts of NO reduction have been developed, the presence of excess O(2) and SO(2) significantly inhibits their performance when they are used to treat the incineration flue gas. To solve such problem, this study prepared new Rh/Al(2)O(3) catalysts and investigated the effects of Na modification, SO(2) and different reductants. Experimental results indicated that the average removal efficiency of NO at such high O(2) concentrations exceeded 80% when the Rh/Al(2)O(3) catalysts were used. CO was a better reductant than C(3)H(6) and the best concentration ratio of reductant/NO was equal to 1. Adding Na to modify Rh/Al(2)O(3) catalysts significantly enhanced the removal efficiency of NO from 80 to 99% at 250-300 degrees C, especially at relative high SO(2) concentrations. Unfortunately, Rh-Na/Al(2)O(3) catalysts do not have long-time activities for NO reduction, possibly because of the formation of NaNO(3). Both Rh/Al(2)O(3) and Rh-Na/Al(2)O(3) catalysts have good performance for NO reduction, they can feasibly be used to reduce NO in the flue gas from waste incineration.