Effect of metals doped TiO2 composite on degradation of methylene blue

Abstract Many types of organic compounds are being discharged in ever-increasing quantities into the environment. In the present work, catalysts composed of titanium dioxide and metals with the presence of ultraviolet light or visible light are used for the degradation of organic contaminants. Single and dual metals (Fe+ 3 and Co+ 2) doped TiO2 were prepared using sol-gel method and wet impregnation methods for the degradation of the methylene blue. The composition and morphology of the prepared catalysts were analyzed using EDX and SEM techniques. The results demonstrated that iron and cobalt are dispersed on the surface and between the interfaces of the TiO2. The diameter of pure TiO2 nanoparticles was 54 nm, while that of Fe-and Co doped TiO2 nanoparticles were 45.6 and 38 nm respectively. The results showed that the degradation of methylene blue using different prepared catalysts were: 80% using pure 500ppm TiO2 with UV irradiation; 60% and 70% using sol-gel 1 g Fe doped 1 g TiO2 with UV and visible lights respectively; 90% and 50% using sol-gel 1 g Fe doped 2 g TiO2 with UV and visible lights respectively. For the case of prepared catalyst by wet impregnation metal- TiO2, the degradation of methyl blue were; 50% and 35% using Fe- TiO2 with UV and visible lights respectively; 50% using Co-TiO2 with both UV and normal lights. However, combing Fe-Co-TiO2 gave 30% degradation with both UV and visible lights. These results indicates that the addition of metals to the TiO2 can improve the degradation of organic materials using visible light irradiation which is impossible with pure TiO2.