A new CQDs/f-MWCNTs/GO nanocomposite electrode for arsenic (10−12 M) quantification in bore-well water and industrial effluents

Abstract

Arsenic (As), a notorious environmental hazard, poses a threat to the lives of several hundred million people. As ion is highly oncogenic even at a trace level. Therefore, its detection is very important for environmental remediation. Herein, the detection of As ion by a simple electrochemical method using glassy carbon electrode (GCE) modified with carbon quantum dots (CQDs), functionalized multiwalled carbon nanotubes (f-MWCNTs) and graphene oxide (GO) in 0.1 M phosphate buffer was investigated. The synthesized nanocomposite (CQDs/f-MWCNTs/GO) was characterized by Fourier transform infrared spectroscopy, high-resolution transmission electron microscopy, Raman spectroscopy, ultraviolet-visible spectroscopy, and X-ray powder diffraction analyses. Electrochemical current response for As ion was examined using cyclic voltammetry and differential pulse voltammetry. An anodic peak of As ion was not affected by common interference ions such as Cr³⁺, Zn²⁺, Fe²⁺, Cu²⁺, Pb²⁺, Hg²⁺, Ca²⁺, Sn²⁺, Mn²⁺, Na⁺, and K⁺. Linear range (0.1–11 nM) and limit of detection (500 pM) were obtained from the direct oxidation of As³⁺ to As⁵⁺. The fabricated As ion sensor exhibited good selectivity, reliability, sensitivity, reproducibility, and long-time stability. It was observed from this study that the CQDs/f-MWCNTs/GO/GCE is a suitable tool for As ion sensing in real samples such as bore-well water and industrial effluents. This platform strategically integrates an electrocatalytic ternary nanocomposite with high performance, which can be extensively employed for fabricating diverse sensors for various environmental applications.