Synthesis of maghemite nanoparticles and its application for removal of Titan yellow from aqueous solutions using full factorial design

Abstract

In this paper, batch adsorption experiments were carried out to investigate the maximum adsorption conditions of the anionic dye Titan yellow on maghemite nanoparticles (γ-Fe2O3). The γ-Fe2O3 nanoparticles were synthesized by co-precipitation method, and the γ-Fe2O3 nanoparticles structure was performed by transmission electronic microscopy, scanning electron microscope, XRD, and Brunauer–Emmett–Teller. The prepared magnetic adsorbent was well dispersed in water and easily separated magnetically from the medium after loaded with adsorbate. The main goal of this study was to analyze the role of experimental factors on the removal of Titan yellow from aqueous solution using full factorial design. The main and interactive effects of four most important variables like pH of the solution, dosage of adsorbent, initial concentration of dye, and contact time were investigated through the model equations designed by a two-level full factorial design. The results were statistically analyzed using the analysis of variance to define important experimental factors and their levels. A regression model that considers the significant main and interaction effects was suggested and fitted the experimental data very well. The optimized conditions for dye removal were at initial pH 6.0, 0.35g L−1 of adsorbent, 30.0 mg L−1 dye, and 25.0 min adsorption time. The adsorption capacity was evaluated using both the Langmuir and Freundlich adsorption isotherm models. The maximum predicted adsorption capacities for Titan yellow was obtained as 839.421 mg g−1. Furthermore, the kinetic of Titan yellow adsorption on γ-Fe2O3 nanoparticles was analyzed using pseudo-first- and second-order kinetic models and the results showed that the removal was mainly a pseudo-second-order process.