Catalytic Oxidation Behavior Of NO Over Heat-treated ACFs

Nitrogen oxides(mainly NO and NO2)are the major components of air pollution and do extremely harm to environment and human health.Activated carbon fibers(ACFs)are well known for their large surface area and abundant micropores and show remarkable catalytic oxidation activity of NO and adsorption capability of NO..This paper focused on the catalytic oxidation behavior of NO(500 ppm)over three kinds of ACFs from different precursors(pitch-based,PAN-based and cellulose-based)at ambient condition.The characterization and catalytic oxidation test results indicated that the determining factor during the adsorption process of NO was the micropores of 0.5?1.0 nm.These ACFs were modified at different temperature(700-1500?)and their catalytic oxidation activity of NO were tested.Results shown that the modified ACFs at low temperature(700?900?)provided more quantity of micropores and better pore size distribution thus performing higher catalytic oxidation activity of NO.The further increase of heat-treatment temperature leaded to a destruction of pore structure of ACFs which will reduce the catalytic oxidation capacity of NO.Besides,cyclic test of cellulose-based ACFs(ST-1000-900?)shown that the adsorption quantity of NOx over ACFs decreased from 3.5 mmol/g to 1.9 mmol/g after the first round cycle.This can be attributed to the generation of oxygen-containing functional groups and the incomplete desorption of NO2.ACFs kept the same equilibrium conversion of NO and adsorption quantity of NOx in the follow cycle test.