芳香烃/环烷烃吸附分离材料研究进展

Advances in adsorbents for aromatics/cycloalkanes separation

吸附法由于其节能环保的特性有潜力替代萃取精馏成为分离同碳数芳香烃/环烷烃的新方法,目前采用的吸附分离材料已从传统的沸石分子筛发展到包括金属-有机框架材料(MOFs)、共价有机框架(COFs)和多孔分子晶体(PMCs)在内的新型多孔材料,体现出优异的选择性、优先吸附芳香烃或环烷烃的能力。本文综述了近年来MOFs、COFs和PMCs在苯/环己烷和甲苯/甲基环己烷分离中的研究进展,重点介绍了三类材料结构的设计思路、吸附分离性能及其机理,包括热力学平衡、分子排阻等两类不同的机理。在取得较大研究进展的同时,该领域也存在一些较为突出的问题,如对吸附质扩散传质规律和混合物固定床分离性能研究不足、对材料稳定性和杂质敏感性关注较少、多孔材料结构复杂、经济性有待提升等,在未来的研究中需予以重视。

Due to its energy efficiency and environmental friendliness,adsorption has the potential to replace extractive distillation as a new method for the separation of aromatics/cycloalkanes with the same amount of carbon atoms.The materials used for adsorption separation have evolved from the traditional molecular sieves to new porous materials,including metal-organic frameworks(MOFs),covalent organic frameworks(COFs)and porous molecular crystals(PMCs),which show preferential adsorption of aromatics or cycloalkanes and excellent selectivity.This review investigated the recent progress of MOFs,COFs and PMCs for the separation of benzene/cyclohexane and toluene/methylcyclohexane,focusing on the ideas of structural design,the adsorption and separation performance and mechanisms of the three types of materials.These mechanisms included two different types of mechanisms such as thermodynamic equilibrium and molecular exclusion.Though remarkable progress had been made,some prominent issues still existed in this field.The laws of diffusion and mass transfer of adsorbent as well as the separation performance of materials loaded in fixed bed for mixtures were inadequately researched,the stability and impurity sensitivity of materials were not caught enough attention,the structures of porous materials were overly complex,and the costs of materials needed to be reduced.All of them needed to be taken into account in future research.