Nanocrystalline ZnMn2O4 Photocatalyst from Spent Zinc-Carbon Batteries for Water Treatment

초록

The alarming increase in pharmaceutical contaminants and toxic dyes in aquatic environments necessitates the development of innovative and sustainable remediation strategies. This study presents a circular economy-driven method to synthesize nanocrystalline ZnMn2O4 photocatalysts from spent zinc-carbon batteries for the degradation of ciprofloxacin, a widely used broad-spectrum antibiotic. The ZnO (from the anode) and MnO2 (from the cathode) are recovered and used as precursors in the solid-state synthesis of ZnMn2O4 via thermal treatment. Characterizations by X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy confirm the formation of a crystalline spinel structure with uniform elemental distribution. The synthesized ZnMn2O4 exhibits strong visible-light absorption with a narrow bandgap of 1.94 eV and high photocatalytic efficiency in degrading ciprofloxacin, with a 71% degradation. The material displays excellent stability, reusability, and degradation kinetics, making it suitable for real-world applications. This work not only provides a sustainable method for valorizing battery waste but also offers a low-cost, environmentally friendly photocatalyst for wastewater processing, following green chemistry guidelines and the circular economy.

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