Adsorption and photo-Fenton catalytic degradation of Orange II dye over cobalt ferrite nanoparticles and almond shell biochar

Abstract The purpose of this work is to synthesize and characterize new materials based on magnetic nanoparticles and almond shell biochar, and to evaluate their ability to remove Orange II dye from water sources. For this purpose, different systems were prepared: magnetic cobalt ferrite nanoparticles (MNP), MNP synthesized on almond shell biochar (BMNP) and a mechanical mixture of MNP and biochar (MM). These systems were characterized by X-ray diffraction, scanning electron microscopy, magnetic measurements and Fourier transform infrared spectroscopy, revealing different structural properties for the three samples. The adsorption kinetic was studied and the equilibrium time tested in this study was 50 minutes. The photo-Fenton catalytic degradation of Orange II was studied. For MNP system, tests were performed under different conditions: varying concentration of catalyst and peroxide, and pH. The concentration of peroxide of 600 ppm, the catalyst concentration of 75 mg/l and pH 3 were the conditions that allowed obtaining higher degradation percentages (> 90%). Under these optimal operation conditions, the dye removal capacity was evaluated for the three systems. BMNP system showed a higher degradation capacity (> 97%) in less time and more than 95% of the sorption capacity remained after 5 successive sorption-washing cycles, suggesting an excellent reusability. These cobalt ferrite nanoparticles synthesized on biochar are presented as an efficient and reusable catalyst to remove dyes like Orange II from wastewater from the textile and food industries using solar energy.