Electrochemical study of chemically modified and screen-printed graphite electrodes with
The preparation and electrochemical characterization of graphite electrodes modified with hexadecylpyridinium-bis(chlorilato)-antimonyl(V), [SbVO(CHL)2]Hex, (CMEs) as well as their behavior as electrocatalysts toward the oxidation of sulfide are described. The self-exchange rate constant ko of immobilized [SbVO(CHL)2]Hex and the effect of the surface coverage were evaluated. [SbVO(CHL)2]Hex is a new compound. Synthesis protocol and some identification studies are given. The fabrication of screen-printed electrodes (SPEs) with a mixture of 5% (w/ w) [SbVO(CHL)2]Hex/graphite powder in 1.5% (w/v) ethyl cellulose in 2-butoxyethyl acetate is also described. SPEs, poised at +0.08 mV versus Ag/AgCl, at pH 6.5 were utilized for the determination of sulfide in simulated wastewater samples. Interference of various compounds was also tested. The proposed method correlates well with a colorimetric method. Calibration graphs were linear over the range 0.01-0.7 mM sodium sulfide and the CV was 2.8% (n = 8) for 0.1 mM sodium sulfide. Recovery ranged from 94 to 102%. Both [SbVO(CHL)2]Hex CMEs and SPE showed very good storage stability. [SbVO(CHL)2]Hex CMEs showed poor working stability in contrast to printed electrodes, which operated with no remarkable loss of their initial activity for more than 100 runs.
Prodromidis
MI
Department of Chemistry, University of Ioannina, Greece.
Veltsistas
PG
Karayannis
MI