“…6 Several techniques have been developed to effectively remove methylene blue, including ozonation, 7 extraction, 8 ion flotation, 9 ultrafiltration, 10 Fenton process, 11 sonolysis, 12 chemical coagulation, 13 adsorption, 14 flocculation, 15 oxidation, 16 and photocatalysis. 17,18 In photocatalytic technology, nano-scaled semiconductor materials have been widely used in recent years because of their low cost, easy synthesis, non-toxicity, and environmental friendliness. 19 Moreover, in the photocatalysis process, numerous essential aspects must be considered, including the band gap energy, effective surface area, light energy absorption characteristics, and optical properties of the photocatalytic materials 20 as well as the operation intensity, temperature, and pH of the photocatalytic degradation.…”