Enhanced Removal of Rhodamine b Dye from Aqueous Media via Adsorption on Facilely Synthesized Zinc Ferrite Nanoparticles

This paper studies the synthesis, characterization, and application of ZnFe₂O₄ nanoparticles for the removal of rhodamine b dye from aqueous media. Utilizing the combustion procedure, ZnFe₂O₄ nanoparticles were synthesized using two different fuels: glutamine (SG) and L-arginine (SA). In addition, the synthesized ZnFe₂O₄ nanoparticles were characterized through various techniques, including Fourier transform infrared (FTIR), X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), energy-dispersive X-ray (EDX), high resolution transmission electron microscope (HR-TEM), and Brunauer-Emmett-Teller (BET) surface area analysis. XRD analysis verified the creation of a ZnFe₂O₄ cubic spinel structure without any contaminants, revealing average crystallite sizes of 43.72 and 29.38 nm for the SG and SA samples, respectively. The FTIR spectra exhibited peaks indicative of metal-oxygen bond stretching, verifying the presence of a spinel formation. Elemental analysis via EDX confirmed the stoichiometric composition typical of zinc ferrite. In addition, FE-SEM imaging displayed that the SG and SA samples are composed of particles with irregular and spherical shapes, measuring average diameters of 135.11 and 59.89 nm, respectively. Furthermore, the BET surface area of the SG and SA samples is 60 and 85 m²/g, respectively. The maximum adsorption capacity of the SA sample (409.84 mg/g) towards rhodamine b dye was higher than that of the SG sample (279.33 mg/g), which was ascribed to its larger surface area and porosity. Kinetic and equilibrium studies revealed that the adsorption process of rhodamine b dye onto the SG and SA samples followed the Langmuir isotherm and pseudo-second-order model. Thermodynamic analysis indicated that the adsorption process was spontaneous, exothermic, and physical. The study concludes that ZnFe₂O₄ nanoparticles synthesized using L-arginine (SA) exhibit enhanced rhodamine b dye removal efficiency due to their smaller size, increased surface area, and higher porosity compared to those synthesized with glutamine (SG). The optimum conditions for the adsorption process of rhodamine b dye were found to be at pH 10, a contact time of 70 min, and a temperature of 298 K. These findings underscore the potential of L-arginine-synthesized ZnFe₂O₄ nanoparticles for effective and sustainable environmental cleanup applications.