The Effects of SiO2 and Zeolite 4A/SiO2 on the Transport Behavior of CO2 and CH4 through Polydimethylsiloxane Nanocomposite Membranes

The Effects of SiO₂ and Zeolite 4A/SiO₂ on the Transport Behavior of CO₂ and CH₄ through Polydimethylsiloxane Nanocomposite Membranes

Abstract

Emmanuel O. Ogbole, Jianzhong Lou, Shamsuddin Ilias

Polymeric membrane-based gas separation provides energy-efficient unit operation in the process  industry. Polydimethylsiloxane (PDMS) is one of the common polymers used for developing mixed matrix membranes (MMMs) for gas separation as it offers one of the highest permeability coefficients for a wide range of gas species, modest selectivity, good material compatibility with inorganic materials, etc.  Single-filler and double-fillers mixed matrix membranes were prepared with polydimethylsiloxane (PDMS) and different weight percent of SiO₂ and zeolite 4A/SiO₂. The effects of the single filler (SiO₂) and double-fillers (zeolite 4A/SiO₂) on the transport behaviors of CO₂ and CH₄ through the nanocomposite membranes were investigated. Permeability of CO₂ and CH₄ through the neat PDMS membrane and the PDMS mixed matrix membranes (MMMs) were experimentally measured. CO₂ and CH₄ permeability were theoretically predicted using Maxwell model. Scanning electron microscopy (SEM) images and visual observation showed that SiO₂ enhanced the uniform dispersion of zeolite 4A in the double-filler-PDMS membrane. The incorporation of SiO₂ nanoparticles and zeolite 4A/SiO₂ disrupted the PDMS polymer chains packing arrangement; thereby, altering the performance of MMMs and the transport behavior of the gases in the single filler (SiO₂-PDMS) MMMs and double filler (zeolite 4A/SiO₂-PDMS). The experimental permeability measurements of CO₂ and CH₄ through the (SiO₂-PDMS) MMMs showed a measure of deviation from the theoretical model. The 2.5wt% zeolite 4A/2.5wt%SiO₂-PDMS MMM exhibited significant average CO₂/CH₄ selectivity improvement over the neat membrane and other MMMs from 3.09 to 4.89.