铁离子改性碳分子筛对氮气/甲烷分离性能的研究

针对碳分子筛对氮气/甲烷分离体系分离比低的问题，采用浸渍法以市售空分碳分子筛（CMS）为基体，制备了分离氮气/甲烷的铁离子改性碳分子筛。通过静态吸附量、分离比、吸附动力学及热力学性质考察了铁离子负载量对碳分子筛吸附分离氮气/甲烷性能的影响。结果表明：铁（Ⅲ）的负载减小了CMS的比表面积、微孔体积和孔径，使CMS超微孔的孔径分布呈现更集中的趋势。这种集中性以动力学性能下降为代价，明显提高了碳分子筛对氮气/甲烷的吸附分离比。在303 K、0.7 MPa条件下，综合性能优异的0.3%铁改性CMS具有6.03的氮气/甲烷吸附分离比。

Study on performance of nitrogen/methane separation on iron ions modified carbon molecular sieve

Aiming at the problem of low separation ratio of carbon molecular sieve to N₂/CH₄ system，the commercial carbon molecular sieve（CMS） for air separation was used as support to prepare the iron ion-modified carbon molecular sieve by an impregnation method.The adsorption and separation performance of nitrogen/methane on different amount of iron modified carbon molecular sieves was systematically investigated by static adsorption capacity，separation ratio，adsorption kinetics and thermodynamic properties.The results showed that the specific surface area，micropore volume and pore size of adsorbent were reduced due to the loading of Fe³⁺ species，making the pore size distribution of ultra-microporous adsorbent be more concentrated.This concentration significantly improved the adsorption and separation ratio of carbon molecular sieves for N₂/CH₄ at the expense of decreased kinetic performance.Under the condition of 303 K and 0.7 MPa，the 0.3%Fe-modified CMS revealed excellent comprehensive performance with a N₂/CH₄ separation ratio of 6.03.