Electrochemical reduction of nalidixic acid at glassy carbon electrode modified with multi-walled carbon nanotubes

Yolanda Patiño; Sanaz Pilehvar; Eva Díaz; Salvador Ordóñez; Karolien De Wael

doi:10.1016/j.jhazmat.2016.10.023

Electrochemical reduction of nalidixic acid at glassy carbon electrode modified with multi-walled carbon nanotubes

J Hazard Mater. 2017 Feb 5;323(Pt B):621-631. doi: 10.1016/j.jhazmat.2016.10.023. Epub 2016 Oct 13.

Authors

Yolanda Patiño¹, Sanaz Pilehvar², Eva Díaz¹, Salvador Ordóñez³, Karolien De Wael²

Affiliations

¹ Department of Chemical and Environmental Engineering, University of Oviedo, Faculty of Chemistry, Julián Clavería s/n, 33006 Oviedo, Spain.
² AXES Research Group, Department of Chemistry, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
³ Department of Chemical and Environmental Engineering, University of Oviedo, Faculty of Chemistry, Julián Clavería s/n, 33006 Oviedo, Spain. Electronic address: sordonez@uniovi.es.

PMID: 27776850
DOI: 10.1016/j.jhazmat.2016.10.023

Abstract

The aqueous phase electrochemical degradation of nalidixic acid (NAL) is studied in this work, using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) as instrumental techniques. The promotional effect of multi-walled carbon nanotubes (MWCNT) on the performance of glassy carbon electrodes is demonstrated, being observed that these materials catalyze the NAL reduction. The effect of surface functional groups on MWCNT -MWCNT-COOH and MWCNT-NH₂-was also studied. The modification of glassy carbon electrode (GCE) with MWCNT leads to an improved performance for NAL reduction following the order of MWCNT>MWCNT-NH₂>MWCNT-COOH. The best behavior at MWCNT-GCE is mainly due to both the increased electrode active area and the enhanced MWCNT adsorption properties. The NAL degradation was carried out under optimal conditions (pH=5.0, deposition time=20s and volume of MWCNT=10μL) using MWCNT-GCE obtaining an irreversible reduction of NAL to less toxic products. Paramaters as the number of DPV cycles and the volume/area (V/A) ratio were optimized for maximize pollutant degradation. It was observed that after 15 DPV scans and V/A=8, a complete reduction was obtained, obtaining two sub-products identified by liquid chromatography-mass spectrometry (LC-MS).

Keywords: Cyclic voltammetry; Degradation; Differential pulse voltammetry; Micropollutants; Quinolones.