Acid gases such as carbon dioxide are removed from air or other gases using a unique carbon-based material. The material is a carbon molecular sieve prepared from oxygen-free precursors carbonized in the absence of oxygen. The pores of the material are then enlarged as by high temperature steaming. Alcohol amines are then used to impart an amine functionality to the materials. A gas to be treated is contacted with this material at room temperature and atmospheric pressure, with the adsorbed gas being released by heating to a moderate temperature.