Electrochemical Detection of Cu Based on ZnO/PVA Nanocomposites and Doped by Cellulose Nanocrystals

Abstract River water must meet environmental and health standards for social uses such as drinking, bathing, agriculture, and sanitation. However, many rivers are contaminated with hazardous substances like copper (Cu), which can be harmful in excess. This study aims to detect Cu in water samples using a Glassy Carbon Electrode (GCE) modified with Zinc Oxide (ZnO), Polyvinyl Alcohol (PVA), and doped with Cellulose Nanocrystals (CNC). ZnO was selected for its chemical stability, wide energy band gap, and exciton binding energy. PVA, a conductive polymer with hydroxyl groups, was used to enhance the surface area, while CNC increased heavy metal adsorption. The ZnO/PVA/CNC nanocomposite was synthesized via the hydrothermal method and characterized using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). Electrochemical properties were tested with Cyclic Voltammetry (CV) and Square Wave Voltammetry (SWV) using a Corrtest potentiostat. The nanocomposite was applied as a thin film to modify the working electrode in GCE measurements. CV results showed a limit of detection (LOD) of 4.12 ppm and a coefficient of determination (R2) of 0.98758, while SWV measurements produced an LOD of 2.52 ppm and an R2 of 0.81282. These findings demonstrate the potential of ZnO/PVA/CNC-modified electrodes for detecting Cu in water samples.