Network Structure Engineering of Organosilica Membranes for Enhanced CO₂ Capture Performance

The membrane separation process for targeted CO₂ capture application has attracted much attention due to the significant advantages of saving energy and reducing consumption. High-performance separation membranes are a key factor in the membrane separation system. In the present study, we conducted a detailed examination of the effect of calcination temperatures on the network structures of organosilica membranes. Bis(triethoxysilyl)acetylene (BTESA) was selected as a precursor for membrane fabrication via the sol-gel strategy. Calcination temperatures affected the silanol density and the membrane pore size, which was evidenced by the characterization of FT-IR, TG, N₂ sorption, and molecular size dependent gas permeance. BTESA membrane fabricated at 500 °C showed a loose structure attributed to the decomposed acetylene bridges and featured an ultrahigh CO₂ permeance around 15,531 GPU, but low CO₂/N₂ selectivity of 3.8. BTESA membrane calcined at 100 °C exhibited satisfactory CO₂ permeance of 3434 GPU and the CO₂/N₂ selectivity of 22, displaying great potential for practical CO₂ capture application.