Preparation of Carbon Molecular Sieves in Reducing Atmosphere for Selective O<sub>2</sub>/N<sub>2</sub> Separation

Carbon Molecular Sieve (CMS) is an ultramicroporous carbonaceous adsorbent, which is widely used in the field of gas separation, especially for air nitrogen separation, as distinguished from activated carbon due to the uniformity of micropore distribution. The separation of nitrogen from air by pressure swing adsorption (PSA method) using carbon molecular sieve in a medium and small scale nitrogen production process is superior to the conventional air cold separation method. Carbon molecular sieves can be prepared from nuts, wood, polyethylene, polyimide, etc., but we used apricot seed husks as carbon substrates. We analyzed the effect of various factors on the properties of carbon molecular sieves prepared from a matrix of apricot seed husks with extremely low ash content of the matrix and high micropore volume to adsorb oxygen, and on this basis, we established a rational preparation process to prepare CMS for nitrogen gas separation. The properties of the carbon molecular sieves prepared under the optimum preparation conditions were 7.2mg/g oxygen equilibrium adsorption, 6.3mg/g adsorption for 1min and 32 selectivity, which were very good for nitrogen separation. The prepared carbon molecular sieve is highly selective and can be used as a very efficient adsorbent for nitrogen separation in air as well as a support for a highly efficient molecular sieve catalyst.