Electrochemical Detection of Arsenic Using Eco-Friendly Zeolite-Graphite Composite Electrode

Abstract

This paper presents an innovative and stable electrochemical sensor using zeolite and graphite for the reliable and accurate detection of arsenic(V). The zeolite materials were hydrothermally synthesized using coal fly ash and fumed silica by-products under specific environments (1.5 M NaOH, L/(Si/Al) ratio of 40, 120°C, and 24 hours), addressing environmental concerns related to wastes managment. The performance of the zeolite-graphite modified electrode (ZGME) was evaluated using voltammetric and impedance techniques at potentials between 1.2 V and -1.2 V (vs. SCE) and a frequency range of 100 kHz to 10 mHz, respectively. The results showed that the incorporation of zeolite for the first time offered notable advantages, such as affordability, simplicity, and improved oxidation-reduction current and peak resolution for arsenic. The ZGME effectively detected As(V) under neutral conditions using a phosphate buffer solution, with a concentration range of 1 x 10-3 to 1 x 10-6 mol.L-1. The sensor achieved a detection limit of 3 μmol.L-1, a quantification limit of 5 μmol.L-1, a sensitivity of 0.28 μA/μM.cm2, and exhibited good reproducibility, opening up new potential for portable zeolite-based electrochemical sensors. Moreover, this research pioneers the use of zeolite as a graphite modifier.