In this study, a new nanoporous carbon was prepared by anodic oxidation treatment to remove noxic ammonia gas. The acid- and base values of the nanoporous carbon were determined by Boehm’s titration method. And, the surface properties of the carbons were investigated by XPS analysis. Also, N2/77K adsorption isotherm characteristics, including the specific surface areas and nano/micropore volumes were studied by BET and t-plot methods, respectively. The ammonia removal efficiency was confirmed by gas-detecting tube technique. As a result, it was revealed in the case of acidic treatment on nanoporous carbons that the ammonia removal was greatly effective due to the increase of OH groups in carbon surfaces without significant changes of nanostructural properties. It was then found that the acidic anodization of nanoporous carbons was a suitable method for the effective removal of ammonia gas, which could be attributed to the increase of acceptor-donor interactions between acidic oxygen functional groups of carbon adsorbent and basic adsorbate in an adsorbent-adsorbate system.