Sustainable Silver Oxide Nanoparticle-Based Electrode for Ultra-Sensitive and Selective Detection of Silver Ions in Aquatic Environment

    In this study, a green synthesis approach was employed to prepare nanoparticles using mint leaves as the source material. These nanoparticles were then used to create an ion-selective electrode through a novel method designed to detect and measure silver ions. The process involved preparing a special paste by mixing graphite powder with silver oxide nanoparticles, which had been synthesized from mint leaf extract using an eco-friendly aqueous method. The physical properties of the nanoparticles were analyzed using XRD, SEM, UV-VIS, and FTIR techniques. X-ray diffraction (XRD) revealed an average crystal size of 15.43nm. Scanning electron microscopy (SEM) showed that the particles were spherical or nearly spherical in shape. UV-VIS spectrometry displayed an absorption peak at 422nm, confirming the successful synthesis of silver oxide nanoparticles. Functional groups were identified using FTIR spectroscopy. The resulting electrode demonstrated high selectivity and excellent sensitivity, showing a linear response over the concentration range of 10⁻¹ to 10⁻⁷ M, with a correlation coefficient of 0.9865. It maintained stability for up to 95 days and was performed optimally at temperatures between 15–30°C and pH values of 6–8. The electrode exhibited a slope of 30mV/ decade at 25°C and had a detection limit of 10⁻⁷ M, with a recovery rate of 100.6%. This method was successfully applied to determine silver ion concentrations in well water and industrial wastewater samples.