Compressive Strength and Water Flux Performance of Type C and Type F Fly Ash-Based Geopolymer Membrane

This study explains the influence of fly ash type C and type F on the properties of membrane geopolymer. The geopolymer paste was synthesized through a mix of fly ash (FA) and an alkaline activator (AA) (2:1 mass ratio of FA:AA). The alkali activator was prepared from sodium silicate and 12 M sodium hydroxide solution in a mass ratio of 1.6. Hydrogen peroxide 3 wt.% was applied as the pore-forming agent, and 4 wt.% glass fiber was employed for reinforcement. The properties of the geopolymer were investigated via Fourier-transform infrared, X-ray diffraction, and scanning electron microscopy. The compressive strength confirmed the higher performance of the type C fly ash-based geopolymer membrane (CFAGM) over the type F fly ash-based geopolymer membrane (FFAGM). On the other hand, FFAGM exhibited an enhanced water permeation flux owing to the larger pore diameter. These results affirmed the excellent performance compared to the previous study.