Thickness Effect on Permeance of CO₂/CH₄ Gases in CA Coated PVDF Composite Membranes

Abstract

The aim of this work is to study the effect of membrane thickness with respect to gas permeance and tensile strength. The influence of membrane thickness on gas permeation has received little attention to date. Single layer flat sheet membrane with average thickness of 25 μm and dual layer composite membranes with variable thickness of skin layer were fabricated by coating CA/ PEG selective layer on the polyvinylidene fluoride porous support. Permeation experiments were performed with CO₂ and CH₄ which revealed that permeance of CO₂ was pronounced compared to CH₄. Highest permeance of 0.87 gas permeation unit (GPU) was obtained at 4 bar with 19.4 μm skin layer. Fourier transform infra-red spectroscopy was used to study the existence of different functional groups in the membranes. Strength of the membranes was analyzed using tensile testing machine. Scanning electron microscopy was used to study the surface structure and morphology. It was found that by reducing the membrane thickness, the permeance of CO₂ and CH₄ increased without compromising on membrane strength.

GRAPHICAL ABSTRACT

Keywords:

• Composite membranes
• Polyvinylidene fluoride
• Polyethylene glycol
• Gas separation
• Selective layer