Synergistic solution of CO2 capture by novel lanthanide-based MOF-76 yttrium nanocrystals in mixed-matrix membranes

A porous and thermally stable metal organic framework (MOF) of yttrium and 1,3,5-benzenetricarboxylate was synthesized, which belongs to the family of lanthanide-based MOF-76. Mixed-matrix membranes were developed by incorporating MOF-76 yttrium nanocrystals into Matrimid® 5218. The structure, composition, and morphology of synthesized lanthanide-based MOF-76 yttrium nanocrystals and mixed-matrix membranes were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. The characterizations and gas permeation results of the prepared mixed-matrix membranes confirmed better adhesion and distribution of filler particles in the polymer. The results demonstrated that the addition of MOF-76 yttrium nanocrystals to the polymer matrix improved both the gas selectivity and permeability of mixed-matrix membranes compared to pure Matrimid membranes. Permeability of CO2 increased from 7.24 to 27.29 Barrer by increasing the particle content from 0 to 30% in pure gas experiments. Whereas with 30 wt% concentration of MOF-76(Y) at 50:50 feed compositions, the selectivity increased for CO2/CH4 and CO2/N2 was 67% and 68%, respectively. The rise in temperature from 298 to 338 K decreased the ideal selectivity up to 25% for both gas pairs due to polymer chain relaxations at elevated temperatures. The commercial importance of membranes was evaluated at different feed compositions and operating temperatures.