Decomposition of organic pollutant in waste water using magnetic catalyst nanocomposite

Abstract

In this study, magnetic recyclable catalyst Fe3O4/CuO/ZnO/nanographene platelets (Fe3O4/CuO/ZnO/NGP) and Fe3O4/CuO/TiO2/nanographene platelets (Fe3O4/CuO/TiO2/NGP) composites were synthesized by simple hydrothermal method. Methylene blue was used as a model of textile dye to evaluate their catalytic activities. A range of analytical techniques including X-ray diffraction, energy-dispersive X-ray spectroscopy and vibrating sample magnetometer were employed to reveal the crystal structure, composition and property of the nanocomposites. The catalytic performance was evaluated by degradation of methylene blue in aqueous solution under UV light and ultrasonic irradiation simultaneously. X-ray diffraction results revealed that cubic spinel Fe3O4, monoclinic CuO, hexagonal wurtzite ZnO and graphene platelets exist in Fe3O4/CuO/ZnO/NGP, while in Fe3O4/CuO/TiO2/NGP nanocomposites instead of hexagonal wurtzite ZnO, anatase TiO2 is observed. These results confirmed that the nanocomposites were the desired materials. In addition, all samples exhibited ferromagnetic behavior at room temperature and could be rapidly separated from aqueous solution for repeated use under external magnetic field. From the degradation of methylene blue, it is found that the as-prepared nanocomposites exhibited excellent catalytic activity compared with nanocomposite synthesized without nanographene platelets. The nanocomposites still retain the 100% of the initial activity after it has been used four times repeatedly.