Electrochemical sensor for thiourea focused on metallurgical applications of copper

Abstract

A simple and reliable device is presented for the direct monitoring of thiourea in copper electrorefinery baths as a tool for reconditioning of industrial baths, and so reducing its environmental impact. For this purpose, a screen-printed graphite electrode is modified with silver nanoparticles (AgNPs) contained in a polyelectrolyte-surfactant matrix. The AgNPs are able to adsorb the thiourea, improving the sensitivity of the electrode toward this analyte, even in the presence of usual additives (Avitone® and glue). The system allows the determination of thiourea in a range of 1-10 mg/L. A coupled electrochemical and IR analysis is proposed to evaluate the involved mechanism.