Green Nanotechnology for Water Purification: Copper-oxide Nanoparticles Bio-assisted with Neem Leaves

Abstract

The presence of heavy metals in wastewater is a major environmental concern due to their toxicity, persistence and bio-accumulative nature. Industrial and agricultural effluents often discharge significant levels of these contaminants, prosing risk to ecosystems and public health. In this study copper oxide nanoparticles synthesized using neem extract (CuONpNm) were explored as a green and cost -effective adsorbent for the purification of contaminated water. Batch adsorption experiment were conducted to assess the influence of pH, initial metal ion concentration and contact time on the removal efficiency of Zn2+, Cu2+, Ni2+ and Cd2+ ion. The structural and morphological features of the nanoparticles were characterized using Scanning Electron Microscopy (SEM). Transmission Electron Microscopy (TEM), and X-ray Diffraction (XRD). Assumption Isotherm were analyzed with the Langmuir and Freundlich model while kinetics data were fitted to pseudo -first order and pseudo-second order equations. The neem-based CuO nanoparticles achieved maximum adsorption efficiencies of 93.715% for Zn2+,90.93% for Cu2+,89.92% for Ni2+ and 83.91% for Cd2+ at pH of 6. CuONpNm showed strong binding power, reaching up to 200mg/l adsorption. The process followed the Freundlich isotherm (R2> 0.994). and pseudo-second-order kinetics (R2> 0.961), providing its efficiency in metal ion removal. These finding highlighted the potential of neem-assisted copper oxide nanoparticles as an efficient, antimicrobial, eco-friendly material for water purification and heavy metal remediation.