Dual-Functional and Low-Toxicity ZnO Nanoparticles From Pomegranate Peel: Impact of Synthesis Parameters on...

The development of eco-efficient multifunctional nanomaterials is crucial for environmental remediation and energy storage. This study systematically investigated the impact of synthesis temperature (25°C vs. 80°C) and zinc acetate concentration (0.5-2 M) on pomegranate peel extract-mediated ZnO nanoparticles. Physicochemical characterization revealed that ambient synthesis (25°C) at 2 M (sample A2) produced an interconnected hierarchical architecture with a specific surface area (SSA_BET) of 12.1 m²/g, a zeta potential of -28.6 mV, and a narrow bandgap of 2.744 eV. Consequently, A2 exhibited superior bifunctional performance, achieving a photocatalytic rate constant (k_app) of 0.065 min^-1 for the degradation of Methylene Blue (10 ppm) and a specific capacitance of 208 F g^-1 at 1 A g^-1. Crucially, electrochemical impedance spectroscopy confirmed that the interconnected framework of A2 provided a negligible charge-transfer resistance (R_p = 0.0043 Ω), facilitating efficient charge transport compared to the resistive, fragmented morphologies produced at 80°C (R_p = 3069.64 Ω). Furthermore, A2 demonstrated low acute ecotoxicity toward Artemia salina (LC₅₀ = 4842 μg/mL). These findings provide a data-driven framework for the low-energy synthesis of high-performance, sustainable ZnO nanomaterials.