Preparation and characterization of PVDF-montmorillonite mixed matrix hollow fiber membrane for gas-liquid contacting process

Abstract

Porous PVDF-hydrophobic montmorillonite (MMT) mixed matrix membranes (MMMs) were fabricated via wet spinning method and used in membrane gas absorption process. The effects of hydrophobic MMT nano-clay loadings (1, 3 and 5 wt% of polymer) on the structure and performance were investigated. The fabricated membranes showed both finger-like and sponge-like structure with an increase in the length of finger-like pores in their cross-section, which resulted in higher permeability and lower mass transfer resistance compared to plain PVDF membrane. Also, significant improvements for surface hydrophobicity, critical entry pressure of water and porosity with the addition of filler were observed. The CO2 absorption test was conducted through the gas–liquid membrane contactor and demonstrated a significant improvement in the CO2 flux with MMT loading and the membrane with 5 wt% MMT presented highest performance. For example, at the liquid water velocity of 0.5 m s-1, CO2 flux of the MMM with 5 wt% MMT of 9.73 × 10-4 mol m-2 s-1 was approximately 56% higher than the PVDF membrane without nano-filler. In conclusion, MMMs with improved absorption properties can be a promising candidate for CO2 absorption and separation processes through membrane contactors.