Electrochemical oxidation of sulfamethazine on a glassy carbon electrode modified with graphene and gold nanoparticles

Author(s)

Cesarino, Ivana ^[1] ; Simoes, Rafael Plana ^[1] ; Lavarda, Francisco Carlos ^[2] ; Batagin-Neto, Augusto ^[3]

Affiliation

^[1] UNESP Univ Estadual Paulista, Coll Agr Sci, Dept Bioproc & Biotechnol, Campus Botucatu, BR-18603970 Botucatu, SP - Brazil

^[2] UNESP Univ Estadual Paulista, Fac Sci, Dept Phys, Campus Bauru, BR-17033360 Bauru, SP - Brazil

^[3] UNESP Univ Estadual Paulista, Campus Expt Itapeva, BR-18409010 Itapeva, SP - Brazil

• Document type: Journal article
• Source: Electrochimica Acta; v. 192, p. 8-14, FEB 20 2016.
• Web of Science Citations: 14

Abstract

This work presents a comprehensive investigation of the oxidation mechanism of sulfamethazine (SMZ) combining electrochemical experiments and molecular modelling techniques. Cyclic voltammetry and differential pulse voltammetry experiments were performed in phosphate buffer solution (PBS) using a glassy carbon (GC) electrode modified with reduced graphene oxide and gold nanoparticles (rGO-AuNPs). Molecular modelling studies were performed via Density Functional Theory (DFT) employing Becke's LYP (B3LYP) exchange-correlation functional and the 6-31G(p,d) basis set. The evaluation of molecular reactivity was accomplished by Condensed-to-Atoms Fukui Indexes (CAFIs). In the theoretical studies, three species were analysed: natural SMZ (SMZ((0))) and its protolytic structures, SMZ((+H)) and SMZ((-H)). The CV results show a well-defined irreversible SMZ oxidation peak at +0.89 V. The molecular modelling studies indicate that SMZ((0)) is the species that effectively participates in the oxidation process. Based on the reactivity indexes obtained, two distinct oxidation mechanisms associated with EC processes occurring in the systems were proposed. (C) 2016 Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 15/02136-2 - Development of advanced materials based on graphene and metal nanoparticles for analysis of antibiotic in wastewater
• Grantee: Ivana Cesarino
• Support Opportunities: Regular Research Grants