Nowadays, the phenomenon of global warming and the amplification of greenhouse gasses due to industrial development and fossil fuel consumption are observed. The carbon dioxide has a significant role in the environmental pollution leading researchers to CO 2 separation and storage via various methodes. Being adaptable to different industries, not needing energy recovery and not wasting the flow, membrane technology, in particular the polymeric ones have drawn attention. However, application of mixed matrix membranes with diverse filler particles were suggested to address the trade-off showed by Robeson. One of the fillers with limited studies is novel covalent organic framework (COF), which carries unique physical properties, e.g., thermal stability, high porousity, large surface area and suitable performance in CO 2 capture. Accordingly, COF was used to fabricate the mixed matrix membranes (MMMs) with copolymer of PEBAX in this study. In this regard, a triazine ring COF based on imine bonds with futuristic structure was synthesized for the first time. The structure, size of crystalline particles with pore size of 27 and their thermal stability were examined with FT-IR, PXRD, FE-SEM, TEM, DLS, EDAX, N 2 adsorption-desorptio and TGA analysis. The obtained results were promising. In addition, ATR, XRD, TGA, tensile stress-strain and single gas permeation analysis were carried out to examine the prepared MMMs. The best performance in terms of gas separation was observed for the MMM with filler loadings of 0.5 wt% and 1% for PEBAX2533 and PEBAX1657,respectively. The separation properties of membranes including permeability and selectivity increased with addition of TCOF to the polymeric matrix until it reached the optimum mass ratio of filler (0.5% and 1%) under pressure of 2 bar and at temperature of 25 The permeation results of T-COF/PEBAX2533 (0.5 %) and T-COF/PEBAX1657 (1%) for CH 4 , N 2 , O 2 and CO 2 were 21.14, 7.97 ,18.93 and 231.84 barrer and 3.99, 1.84, 4.35 and 109,85 barrer, respectively. And the selectivity results of CO 2 /N 2 , CO 2 /CH 4, O 2 /N 2 for COF/PEBAX2533 were 29.11, 10.97 and 2.38 and 59.70, 28.65 and 2.35 for PEBAX1657, accordingly. Subsecuently, membrane performance enhanced in the order of 17% , 16%, 20% and 29% for gas permeation of PEBAX2533 and 15%, 27%, 55% and 47% for that of Pebax1657. As for selectivity, the improvements were 11% (CO 2 /N 2 ), 10% (CO 2 /CH 4 ) and 3% (O 2 /N 2 ) for PEBAX2533 and 15% (CO 2 /N 2 ), 33% (CO 2 /CH 4 ) and 23% (O 2 /N 2 ) for PEBAX1657, respectively.
