Template-free hydrothermal synthesis of hexa ferrite nanoparticles and its adsorption capability for different organic dyes: Comparative adsorption studies, isotherms and kinetic studies

Abstract

The comparison of adsorption of hazardous dyes such as Evans blue, Congo red and Rhodamine B is studied using novel calcium hexaferrite (CaAl5Fe7O19) nanoparticles, which are synthesized through the solution combustion method. During the synthesis process, the calcium hexaferrite nanoparticles are doped with 15.5% of aluminum nitrate. The synthesized doped-ferrite nanoparticles are characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The comparative adsorption studies of three different hazardous environmental chemical pollutants such as Evans blue, Congo red and Rhodamine B dye were investigated by batch adsorption experiments with varying influencing parameters such as dosage effect, dye concentration, pH and contact time. It is found that the maximum adsorption for Evans blue (90.85%) at the wavelength of 608 nm, Congo red (58.17%) at 418 nm, and Rhodamine B (65.6%) is at 627 nm. Freundlich and Langmuir’s adsorption are compared and the results obtained matches well with the Freundlich isotherm model. Such novel materials have the potential for applications in environmental remediation. Keywords: Metal oxide nanoparticles, Hexa ferrite, Morphology, Chemical pollutant removal, Organic dyes, Adsorption mechanism, Isotherms