Modification of Magnetic Activated Carbon Nanoparticles with Phosphotungstate for Photocatalytic Application under Sunlight, and Visible, Irradiation

Recently, considerable attention has been focused on heteropoly acids including their anions (polyoxometalates or POMs) due to many advantages such as simple preparation, high reactivity, non-corrosive, non-pollutant and excellent stability. POMs have been used as photocatalysts for the destruction of dyes. Discharge of wastewater of synthetic dyes to environment affects both living organisms of aquatic ecosystems and human health due to toxicity and carcinogenicity. Consequently, treatment of dye-contaminated wastewaters with decontamination processes is necessary before their discharge. In this study, magnetic activated carbon nanoparticles (MAC) were coated with an organic hybrid of phosphotungstic acid that makes MAC suitable for adsorption and photocatalytic degradation of dyes. The prepared composite was characterized by Fourier transform infrared spectroscopy, powder X-ray diffraction, thermal analyses, scanning electron microscopy and vibrating sample magnetometer. Dye adsorption and photocatalytic properties of composite was examined by studying the decolorization of model dyes methylene blue (MB), methyl orange (MO) and their mixture solutions. The results show that the composite can selectively adsorb MB molecules from binary mixtures of MB/MO. While the visible light is not able to degrade alone MO solution in the presence of composite, it degrades the MO mixed with MB solution. The composite is, unlike MAC, a good photocatalyst in the degradation of dyes under sunlight and visible irradiation and can be separated by magnet, recovered and reused. Removal is via combination of adsorption and then photocatalytic degradation through direct oxidation by composite.