End-of-life waste criteria: synthesis and utilization of Mn–Zn ferrite nanoparticles as a superparamagnetic photocatalyst for synergistic wastewater remediation

Abstract

Dyes are toxic compounds that are widely included in industrial discharge. Their efficient and economical remediation can be explored through Fenton’s oxidation. Mn0.6Zn0.4Fe2O4 nanoparticles are prepared via a simple and efficient co-precipitation technique and its chemical composition is confirmed through X-ray diffraction and its morphology via high-resolution transmission electron microscope. The prepared superparamagnetic photocatalyst based on Mn0.6Zn0.4Fe2O4 is applied for almost complete Synozol Blue dye removal (98% dye removal and 87% COD removal) and the results confirmed that the process is an efficient sustainable technique for the easily magnetically recoverable catalyst. Central composite design analysis was chosen to optimize the parametric conditions of the magnetized Fenton’s variables through 13-level of a quadratic model. The optimized system variables were attained at 39 and 404 mg L−1 for catalyst and H2O2, respectively, at pH 3.0 with model correlation coefficients over than 98%. Recover and reuse are a viable option for ‘close the loop’ waste after final treatment as an ‘end-of-life’ waste potential and high removal efficiency is attained up to the 8th cycle of catalyst reuse. Kinetics of Synozol Blue oxidation fitted through the first-order kinetic model. Finally, the thermodynamic parameters values concluded that the process is non-spontaneous and endothermic in nature.