Fabrication of CA/PEG/MWCNTs composite membranes for enhanced CO2/CH4 separation

Gas separation process through membrane technology has greatly improved greenhouse effect. Membrane technology is considered important for gas separation. The aim of this work was to study the effect of membrane thickness with respect to gas permeance and tensile strength. Single layer flat sheet membrane with thickness of 45 mu m and dual layer composite membranes with variable thickness were fabricated by coating cellulose acetate/poly-ethylene glycol/multi-walled carbon nanotubes selective layer on the polyvinyl alcohol (PVA) porous support. Fourier transform infrared (FT-IR) spectroscopy was utilised to study the existence of different organic groups in the membranes. The crystal structures of MWCNTs in the membranes were characterised by X-ray diffraction (XRD). Tensile testing machine was used to analyse the maximum strength of the prepared membranes. Scanning electron microscopy (SEM) was used to study the surface structure and morphology of the composite membranes. The reduction in the thickness of the selective layer up to 8 mu m resulted in a maximum CO2 permeance of 0.92 GPU. It was concluded that by reducing the membrane thickness the gas permeance increases.