Efficient mesoporous cross-linkable hybrid poly Schiff-base based on polyimide as a promising molecular sieve for sustainable CO₂ capturing and separation

ABSTRACT

A cross-linked hybrid poly Schiff-base (PSB) was synthesized and characterized through spectroscopic, morphological, and structural approaches. The BET surface area (S_BET) of the PSB is 20.33 m²/g, the pore volume (V_p) is 0.024 cm³/g, and the pore diameter (D_p) is 4.13 nm. The current study elucidates PSB’s strong chemical and thermal stability, as well as the remarkable capacity to adsorb CO₂ with perfect selectivity. This property is accomplished by the synergistic interaction of the polymer’s physicochemical and structural features when exposed to CO₂, N₂ and CH₄ molecules. This mesoporous polymer exhibits a CO₂/N₂ = 60 and CO₂/CH₄ = 10.5 selectivity, and can adsorb 3.22 mmol/g CO₂ (at 298 K/1 bar). Furthermore, the isotherms of CO₂ gas adsorption and desorption in the porous polymer are reversible. The use of PSB having effective imide, imine, and meta-hydroxyl functional groups in the adsorption and selectivity of CO₂ gas produced excellent results, which make it a suitable candidate for CO₂ storage and separation applications.

KEYWORDS:

• Porous organic polymer (POP)
• Schiff-base
• gas separation
• polyimide
• CO₂ capture

Acknowledgments

The authors thank the Research Council of the University of Kharazmi and the University of Mazandaran for their partial support of this work.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Additional information

Funding

The work was supported by the University of Mazandaran.