Alternative Electrochemical Determination of Cyanide Using a Carbon Paste Electrode Modified by Natural Clay in Contact with <i>Moringa Oleifera</i>

Abstract

Cyanide is increasingly released into the environment as a result of human activities. Once ingested into the body, it blocks vital functions and can lead to death. The aim of this work is to detect cyanide using cathodic stripping voltammetry employing a carbon paste electrode modified with 5% Agban Bingerville clay. Two electrochemical sensors were developed for the detection of cyanide: one with a bare carbon paste electrode and the other with a clay-modified carbon paste electrode. The modified electrode detects cyanide in a hydrochloric acid (pH 1) supporting electrolyte seven times more effectively than the bare carbon paste electrode. Its detection limit is 1.41 µmol/L or 0.04 mg/L, and its sensitivity is 4458 μA cm−2μM−1. This value is below the cyanide concentration limit set by the World Health Organization (WHO) for drinking water. This sensor can therefore contribute to the routine monitoring of environmental matrices. After detection, Moringa oleifera seed powder helps eliminate the cyanide from the solution. The optimum mass of seed powder, which removes 77% of cyanide, is 0.08 g for a 10 mL cell after stirring for 10 min. The elimination occurs as a result of electrostatic interactions between positively charged Moringa proteins and cyanide.