Effect of acid treatment on surfaces of activated carbon supported catalysts for NO and SO2 removal

To study the effect of different modification reagents on activated carbon (AC), HNO3, H2SO4, H2O2, H2C2O4, and H3PO4 were chosen to modify AC. Then a series of Mn/AC catalysts were prepared by impregnation method. The denitrification performance and SO2 adsorption activities of these catalysts were tested. The results indicated that the catalyst prepared by HNO3-modified AC has both the highest NO conversion and SO2 adsorption activity. The NO conversion can reach 80% at 180 degrees C and SO2 saturated adsorption time can reach 30 min. To investigate the enhanced modification mechanisms of HNO3, the various modified samples were characterized by SEM-EDS, XPS, FTIR, and NH3-TPD. And the results show HNO3 can effectively increase the amount of chemical adsorbed oxygen on the surface of AC. And on the other hand, the nitrogen-containing functional groups introduced by HNO3 can promote the adsorption of NO, thus improving the denitrification performance. As a result, HNO3 can play a better role in activating AC, and the catalyst modified by HNO3 is more conducive to be used as the carrier of SCR catalysts.