Synthesis of metal doped nano-ferrites Co0.5Zn0.25M0.25Fe2O4 by co-precipitation method and application as adsorbent and photocatalyst for removal of direct orange-108 acid dye: equilibrium, kinetic and thermodynamic studies

In this study, metal-doped quaternary nano ferrites (Co_0.5Zn_0.25M_0.25Fe₂O₄, M = Ba, Cu, Mn, Ni and Sr) were synthesized and evaluated for their efficiency in removing Direct Orange-108 Acid Dye from aqueous solutions. The adsorption performance of these materials was systematically investigated under various conditions. Optimal pH levels for dye removal were found to be pH 2 (41.45 mg/g), pH 2 (36.37 mg/g mg/g), pH 4 (31.13 mg/g), pH 4 (44.75 mg/g), and pH and 3 (39.62 mg/g) at optimal dosage of 0.05 g/50 mL and at an initial concentration of at 75 ppm and 50 ppm for Co_0.5Zn_0.25Ba_0.25Fe₂O₄, Co_0.5Zn_0.25Cu_0.25Fe₂O₄, Co_0.5Zn_0.25Mn_0.25Fe₂O₄, Co_0.5Zn_0.25Ni_0.25Fe₂O₄ and Co_0.5Zn_0.25Sr_0.25Fe₂O₄ respectively. Additionally, the study revealed that an optimum temperature of 40 °C enhanced the adsorption efficiency, resulting in adsorption capacities of 41.92 mg/g, 40.56 mg/g, 33.22 mg/g, 48.00 mg/g, and 43.71 mg/g for Co_0.5Zn_0.25Ba_0.25Fe₂O₄, Co_0.5Zn_0.25Cu_0.25Fe₂O₄, Co_0.5Zn_0.25Mn_0.25Fe₂O₄, Co_0.5Zn_0.25Ni_0.25Fe₂O₄ and Co_0.5Zn_0.25Sr_0.25Fe₂O₄ respectively. The shaking time with optimal results were obtained at 45 and 60 min. Similarly, as a photocatalyst have optimal pH at 2, 3 and 4, optimum dose 0.05 g/50 mL, initial concentration of dye was 50 and 75 ppm with contact time of 45 and 60 minutes at 40 °C as optimum temperature. The pseudo second order adsorption kinetic model and Langmuir adsorption equilibrium isotherm displayed strong fitting for experimental data. While degradation kinetic follow BMG and second kinetic model. NH₄OH solution showed maximum desorption The thermodynamic study demonstrated the exothermic character. The adsorption study of real textile effluents was also conducted that yielded valuable information. Highlights: Novel metal doped quaternary nano ferrites Co_0.5Zn_0.25M_0.25Fe₂O₄ (M = Ba, Cu, Mn, Ni and Sr) were synthesized, characterized, and used for dye adsorption. Langmuir adsorption isotherm and pseudo second order kinetic model fitted best and proved most appropriate for this study. The size, changeable properties and shape are the most notable characteristics of nano ferrites, therefore the use of ferrites in many applications is enhancing day by day. [ABSTRACT FROM AUTHOR]