Cu0.5Ni0.5MnxFe2-xO4 magnetically separable nano ferrites: A highly efficient photocatalyst for degradation of dye under solar light irradiation

One of the most important challenges in environmental remediation, especially for the treatment of wastewater contaminated with dyes, is the development of highly effective and readily recoverable photocatalysts. In order to overcome this, novel magnetically separable Cu 0.5 Ni 0.5 Mn x Fe 2-x O 4 (where x = 0.0–1.0) nano ferrites were successfully synthesized using a sol-gel auto-combustion technique and annealed at 800°C. X-ray diffraction (XRD) analysis confirmed the formation of a single-phase spinel structure, while Raman spectroscopy revealed slight structural distortions induced by Mn doping. FESEM and TEM characterizations exhibited an aggregated morphology of partially developed nanoparticles, with elemental composition and oxidation states validated by EDX and XPS, respectively. Crucially for practical catalyst recovery, VSM analysis demonstrated robust magnetic properties; although the saturation magnetization (Ms) decreased from 64.176 emu/g to 30.995 emu/g with increasing Mn substitution, the ferrites retained sufficient magnetization for rapid and facile separation from the reaction medium using an external magnet. The optical band gap, estimated via UV-DRS, indicated favourable solar light absorption. The photocatalytic efficacy of these nano ferrites was evaluated through the degradation of Reactive Orange (RO) dye under natural solar irradiation. Remarkably, the x = 1.0 composition exhibited the highest photocatalytic degradation efficiency, benefiting from optimized band structure and enhanced charge carrier separation. Furthermore, the catalyst demonstrated excellent stability and reusability over multiple cycles. These findings establish the Cu 0.5 Ni 0.5 Mn x Fe 2-x O 4 system as a highly promising, magnetically recoverable platform for practical and sustainable wastewater treatment. • Cu 0.5 Ni 0.5 Mn x Fe 2-x O 4 nano ferrites were synthesized using Sol gel Auto combustion method. • Cu 0.5 Ni 0.5 Mn x Fe 2-x O 4 nano ferrites were used for degradation of Reactive Orange Dye. • Cu 0.5 Ni 0.5 MnFeO 4 (CNMF5) nano ferrite achieved 99.4% degradation of RO dye within 90 min under natural sunlight.