改性碳分子筛是一种优秀的多孔吸附剂，多用于空分制氮等领域。但吸附剂的发展制约着变压吸附工艺的应用范围，优异的吸附剂需要更好的分离性能。以工业碳分子筛（CMS）为基础，以硝酸镁为改性剂，采用等体积浸渍法制备了一系列改性碳分子筛。通过体积法测量了在变压吸附法（PSA）工艺条件下（303 K，0~0.7 MPa，200 s）甲烷和氮气在硝酸镁改性碳分子筛上的吸附特性。分别将吸附等温线实验数据及动力学曲线数据拟合到Sips模型和LDF模型，得到一系列改性碳分子筛的分离性能及吸附特性参数。结果表明，硝酸镁改性处理降低了CMS的比表面积、微孔体积、平均孔径，同时使得孔径分布更集中。通过调节碳分子筛孔径分布，改性后的碳分子筛展现出更好的氮气选择性，性能优异的样品CMS-0.5在303 K、0.4 MPa下，分离比达到12.20。

Modified carbon molecular sieve is an excellent porous adsorbent，which is mostly used in fields such as air separation and nitrogen production.However，the development of adsorbents restricts the application range of pressure swing adsorption process，and excellent adsorbents require superior separation performance.A series of modified CMS were prepared by equal volume impregnation method with magnesium nitrate as modifier based on industrial CMS.The adsorption characteristics of methane and nitrogen on these adsorbents were measured by the volumetric method under PSA process conditions（303 K，0~0.7 MPa，200 s）.The adsorption isotherm experimental data and kinetic curve data were fitted by using the Sips model and the LDF model，respectively，and the separation performance and adsorption characteristic parameters were obtained.The results showed that the modified carbon molecular sieves treatment reduced the specific surface area，micropore volume and average pore size of CMS，while making the pore size distribution more concentrated.The modified CMS with narrow pore size distribution exhibited better nitrogen selectivity owing to regulating the pore size distribution of CMS，and the excellent CMS-0.5 sample had a separation ratio of 12.20 at 303 K and 0.4 MPa.