Pithecellobium dulce as efficient and sustainable source for biosynthesis of NiO nanoparticles with promising potential for degradation of Malachite green and antibacterial activity

Abstract

This study reports the sustainable biosynthesis of nickel oxide nanoparticles (NiO NPs) using Pithecellobium dulce leaf extract as a natural reducing and stabilizing agent. Characterization via XRD, SEM, and EDX confirmed the formation of pure, hexagonal-crystalline NiO NPs with an average crystallite size of 12.49 nm and a particle size of 27.56 nm. Optical analysis revealed a direct band gap of 2.8 eV, while TGA demonstrated exceptional thermal stability up to 931°C. The synthesized nanoparticles exhibited potent, concentration-dependent antibacterial activity against both Gram-positive and Gram-negative pathogens. Furthermore, the NiO NPs functioned as an efficient photocatalyst, achieving 100% degradation of Malachite Green dye within 60 minutes under visible light at optimized conditions (pH 9, 60 mg dosage). These results highlight the potential of P. dulce mediated NiO NPs as high-performance materials for environmental remediation and biomedical applications.