Header menu link for other important links
X
An Unusual Electrochemical Reductive Cleavage of Azo Dye into Highly Redox Active Copolymeric Aniline Derivatives on a MWCNT Modified Electrode Surface at Neutral pH and Its Electroanalytical Features
Published in American Chemical Society (ACS)
2015
Volume: 119
   
Issue: 14
Pages: 7791 - 7801
Abstract
Developments of new decomposition or degradation methods of environmentally hazardous azo dyes from textile industries are very important. Usually, strong acid-based chemical/electrochemical and neutral pH-based bacterial decomposition methods were widely used. Here, we report a mild, simple, and facile electrochemical method for decomposition of azo dye (Sudan yellow; SY) into a highly redox active copolymer of polyanilines via aniline derivatives as intermediates on a MWCNT modified glassy carbon electrode (GCE/MWCNT) surface unusually in a neutral pH using phosphate buffer solution (PBS) (GCE/MWCNT@SY-CoPANIpH7). One of the intermediate products, aniline (Mw = 93 mol g-1, calculated) was identified by an in situ cyclic voltammetry-electrochemical quartz crystal balance experiment. No such SY electrochemical reaction was observed on a naked GCE surface. Physico-chemical characterizations by TEM, Raman, IR, and UV-vis spectroscopic methods supported the formation of polymeric product on MWCNT surface (GCE/MWCNT@SY-CoPANIpH7). Electroanalytical performance of this new electrode was tested using ascorbic acid (AA) and Fe(CN)63-, as models. Interestingly, a dilute solution of Nafion (Nf) casted modified electrode system (GCE/MWCNT@SY-CoPANIpH7/Nf) showed improved electroanalytical performance, unlike the conventional Nafion modified system (GCE/MWCNT/Nf) with vanished peak current response due to the electrostatic repulsive interaction between the anionic AA (pKa = 4.10), Fe(CN)63- ion, and anionic sulfonic acid groups in Nafion. A zwitter ionic complex between a polaronic copolyaniline and sulfonic acid of Nafion is proposed as a possible structure for the newly developed hybrid system. Using the GCE/MWCNT@SY-CoPANIpH7/Nf, a selective flow injection analysis of AA has been demonstrated as an analytical application with good recovery values. © 2015 American Chemical Society.
About the journal
JournalData powered by TypesetThe Journal of Physical Chemistry C
PublisherData powered by TypesetAmerican Chemical Society (ACS)
ISSN1932-7447
Open Access0
Authors (3)