Coal Fly Ash Derived Silica Nanomaterial for MMMs-Application in CO₂/CH₄ Separation

In order to obtained high selective membrane for industrial applications (such as natural gas purification), mixed matrix membranes (MMMs) were developed based on polysulfone as matrix and MCM-41-type silica material (obtained from coal fly ash) as filler. As a consequence, various quantities of filler were used to determine the membranes efficiency on CO₂/CH₄ separation. The coal fly ash derived silica nanomaterial and the membranes were characterized in terms of thermal stability, homogeneity, and pore size distribution. There were observed similar properties of the obtained nanomaterial with a typical MCM-41 (obtained from commercial silicates), such as high surface area and pore size distribution. The permeability tests highlighted that the synthesized membranes can be applicable for CO₂ removal from CH₄, due to unnoticeable differences between real and ideal selectivity. Additionally, the membranes showed high resistance to CO₂ plasticization, due to permeability decrease even at high feed pressure, up to 16 bar.