Supported ionic liquid membrane(SILM) is a kind of composite membrane, which is prepared by immobilizing ionic liquids(ILs) into the porous membrane. It combines the excellent solvent properties of ILs and high efficiency of membrane separation, and also has the advantages of simplified separation processes and economical operating cost, which all make SILM become one of the academic focal points of CO₂ capture. It depends on the stability and quality of SILM for applying this kind of membrane separation in desulfuration and decarbonization of natural gases and flue gases. High-quality porous membranes, task-specific ILs and scientific preparation methods are of importance in guaranteeing the performances of SILMs. Preparation methods and typical characterization methods of SILMs are summarized in this work, So are the relative merits of different preparation methods. In addition, the factors affecting the stability and life time of SILM are analyzed and evaluated. On the basis of the comments above, the key scientific problems of SILM-quality control and future research direction for further development are proposed, for the purpose of promoting the basic studies of SILM technologies to guide industrialized applications and development.

Contents
1 Introduction
2 Preparation methods of SILM and their features
2.1 Conventional preparation methods of SILM
2.2 Preparation of SILM by reducing viscosity
2.3 Novel ionic liquid membrane and their preparation
3 Characterization methods of SILM
4 Stability and uniformity of SILM
4.1 Stability
4.2 Uniformity
5 Conclusion and outlook