EFFECTS OF AMINO-FLUORINATED CARBON MOLECULAR SIEVE ON BREAKTHROUGH CURVE BEHAVIOR IN CO_2/CH_4 SEPARATION

摘要

Introduction In this study, high-performance CO_2/CH_4 separation behavior of carbon molecular sieve (CMS) was prepared by the amino-fluorination of CMS with using NF_3 gas. The amino-fluorinated CMSs were carried out with various concentrations of NF_3. The amino-fluorination of CMS introduced functional groups of nitrogen and fluorine which are beneficial for the CO_2/CH_4 separation behavior without the change of pore structures. In previous studies, the reaction with NF_3 gas can be expected to take place at carboxylic acid sites formed by the oxidation of side groups and the ring system. NF_3 gas decomposes at room temperature with the formation of radicals, such as NH_2, NH and Η [1]. These radicals may react with the carbon surface to form functional groups, such as -NH_2-, -CN, et al [2]. Also, the relationship between the CO_2 adsorption capacities and CO_2/CH_4 gas separation behavior of amino-fluorinated CMSs is discussed. The breakthrough and saturation times for the adsorption of CO_2 on amino-fluorinated CMSs were longer and shorter than raw CMS. So, it is concluded that the proper contents of nitrogen and fluorine groups improved the CO_2/CH_4 separation behavior.