Synthesis and Characterization of SAPO-34/ Fluorinated Polyimide Composite Membrane for Biogas Purification

¹ Centre for Sustainable Energy, Environment and Social Innovation (SEESI), Universiti Teknologi PETRONAS, 32610 Bandar Seri Iskandar, Perak, Malaysia.
² Chemical Engineering Department, Universiti Teknologi PETRONAS, 32610 Bandar Seri Iskandar, Perak, Malaysia.

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

The growing demand for renewable energy has increased the need for efficient biogas upgrading to produce high purity biomethane. While polymeric membranes offer an energy efficient separation method, their performance is limited by the permeability and selectivity trade-off. Incorporating inorganic fillers into polymers to form composite membranes is a promising strategy to overcome this limitation. In the present work, a series of SAPO-34/fluorinated polyimide composite membranes were synthesized for CO₂ removal from CH₄ in biogas by incorporating inorganic filler loadings of 1 4 wt.% into the polymer matrix. The morphology of the membranes were characterized using Field Emission Scanning Electron Microscopy (FESEM) and their CO₂/CH₄ separation performance was evaluated. FESEM images show that SAPO-34 particles were uniformly dispersed within the polymer matrix, with no particle agglomeration or significant interfacial voids between the filler and polymer phases. All composite membranes exhibited higher selectivity compared to the virgin polymer membrane, with the membrane containing 3 wt.% SAPO-34 achieving the highest selectivity of 84.99. Furthermore, the membranes loaded with 3 wt.% and 4 wt.% SAPO-34 were able to surpass 2008 Robeson upper bound. Overall, the incorporation of an optimal SAPO-34 loading enhances CO₂/CH₄ separation performance, demonstrating strong potential for efficient biogas upgrading applications.