Photocatalytic geopolymer membranes from Indonesian fly ash: TiO2 integration, stability, and methylene blue degradation

Abstract

This study reports TiO₂-modified geopolymer membranes synthesized from Indonesian Class C and F fly ash for methylene blue (MB) degradation. TiO₂ (0–5 wt%) improved compressive and flexural strength, with Class C showing faster setting and higher strength at 3 wt% TiO₂. MB removal reached up to 99.3 %, although permeability declined with increased TiO₂. UV-assisted regeneration restored membrane performance over three filtration cycles, demonstrating self-cleaning capability. These findings highlight the potential of fly ash-based photocatalytic geopolymer membranes for wastewater treatment applications.