Rice Straw Derived Nano‐Silica as a Sustainable Electrode Modifier for Electrochemical Detection of Arsenic in Groundwater

ABSTRACT A novel composite utilizing nano‐silica (NS) derived from rice straw was developed for an NS‐carbon paste electrode. Rice straw was carbonized to produce NS via precipitation, with pH adjustments and chemical reactions facilitating silica formation. Further chemical treatments enhanced silica purity and properties. Characterization via XRD and FTIR has been performed along with SEM, and TEM revealed very high surface area of 189.64 m 2 /g as well as the structure of 3D with interconnected open spaces, ideal for electrode applications. The NS (200 nm) was size‐reduced using cryomill. A composite of carbon black, NS, graphite powder, and polyvinylpyrrolidone (PVP) binder was prepared and drop‐cast onto a glassy carbon electrode (GCE). Cyclic voltammetry (CV) and chrono‐amperometric methods evaluated fabricated electrode's performance in detecting toxic arsenic ions in groundwater. Compared to a bare GCE, the fabricated NS electrode displayed distinct oxidation/reduction peaks and higher response currents. To elucidate the electrochemical response, the impact of scan rate was also examined. Additionally, analytical detection was done utilizing the differential pulse voltammetry (DPV). This created electrode manifested arsenic detection with high sensitivity, suggesting that it might be utilized to monitor hazardous metal ions in ground water samples.