The photocatalytic degradation of methylene blue (MB) of the geopolymer paste with addition nanoparticles titanium dioxide (TiO2) was investigated under illumination of sunlight radiation. In this work, TiO2-based geopolymer paste was prepare by dry mixing of Class F fly ash (FA) and different amount of nano-TiO2 (0, 2.5, 5.0, 10.0 & 15.0 wt%). Then, the alkali activator, which is combination of sodium hydroxide solution with sodium silicate was added to the dry mix FA-TiO2 with ratio of 2.5. All the sample was cured at room temperature and aged for 28 days. The photocatalytic behaviour of nano-TiO2 was evaluated and compared through photocatalytic testing and surface degradation testing by measuring the photodegradation of MB under sunlight rays. The experimental results revealed that the addition of nano-TiO2 to the geopolymer paste shows excellent result on photocatalytic degradation of MB after exposure to sunlight up to 150 minutes.
