Functionalization of silica membranes for CO2 separation

•Novel functionalized silica membranes were prepared and used for CO2 separation.•The successful incorporation of functional groups in silica network was evidenced.•The majority of the pores were micropores according to permporometry experiment.•The interactions between applied functional groups and CO2 were also studied.•CF3 and vinyl functionalized silica membranes showed the best performance.