This study aims to investigate the photocatalytic activity of ZnO nanoparticles as photocatalyst material which was doped onto a geopolymer paste. ZnO-doped geopolymer paste were prepared by mixing Class F fly ash and various amount of ZnO nanoparticles with alkali activator, which is combination of sodium hydroxide solution with sodium silicate. Meanwhile, geopolymer paste without ZnO was produced by mixing Class F fly ash and alkali activator. Then, both samples were cured in room temperature and aged for 28 days. The photocatalytic activity for geopolymer paste with and without ZnO nanoparticles were evaluated and compared through photocatalytic testing and discolouration testing. The experimental results revealed that, as increasing the amount of addition ZnO nanoparticles, the degradation of methylene blue also was increased. However, mineralogical determination of ZnO-doped geopolymer paste were characterized using X-ray Diffraction (XRD).
