Faradaic processes on activated carbon particles: Example of sulfite anodic oxidation

Abstract

Activated carbon has often been reported as a suitable material for numerous applications e.g. energy storage, batteries and pollution control, due its high adsorption capacity allowed by its high surface area. Besides, activated carbon can also be used for the chemical transformation of matter through faradaic processes. This paper deals with the performance of activated carbon (AC) particles as an electrode material for the anodic oxidation of sulfite and bisulfite species into sulfate. The oxidation was carried out at the surface of a packed-bed of AC particles (volume 170 cm3); the main operating conditions, namely potential and solution pH were varied. The sulfate production was shown to be controlled by the electrode kinetics and the internal transfer in the carbon pores. Interactions between the capacitive phenomena, occurring in the electrical pretreatment, and the faradaic processes were discussed.Le charbon actif est souvent decrit c o m e un materiau bien adapte a de nombreuses applications, tels que le stockage d'energie, les batteries ou les procedes de depollution, qui font appel a sa grande capacite d'adsorption due a sa tres grande surface specifique. Hormis ces applications, ce materiau peut egalement &tre utilise pour la transformation chimique de la matiere par des processus faradiques. Nous avons etudie les performances d'une electrode constituee de particles de charbon actif dans le cas de I'oxydation anodique de sulfite et de bisulfite en sulfate. L'oxydation a ete menee sur la surface d'un lit fixe (volume de 170 cm3) de ces particules en faisant varier le potentiel applique et le pH de la solution.La conversion en sulfate est contrdee par la cinetique de transfert electronique et la difision interne dans les pores. Les interactions entre les phenomenes capacitifs se produisant pendant l'operation de pre-traitement de I'electrode et les processus faradiques font l'objet d'une discussion.

Electrochemical Oxidation of Wine Polyphenols in the Presence of Sulfur Dioxide

“…This is a surprising result, as the oxidation of one molecule of SO 2 at glassy carbon surface was considered to involve two electrons. 21,46 In order to check that there were no chemical reactions occurring between SO 2 and the components of the model wine solution, giving rise to extra loss of sulfur dioxide, electrolysis was also conducted in ultrapure water. The same reaction rate for SO 2 loss was observed.…”

“…Given that a current of 400 μA/L provides for 4.15 × 10 –9 moles of electrons passed per liter, by Faraday’s law of electrolysis (eq ), this result implies that n was equal to 1. This is a surprising result, as the oxidation of one molecule of SO 2 at glassy carbon surface was considered to involve two electrons. , …”

Amperometric Sulfite Sensor Using Electrodecorated Pt Particles onto an Aminated Glassy Carbon Electrode Prepared by Stepwise Electrolysis

“…[18][19][20][21][22] Electrochemical sulfite detection may be based on direct sulfite reduction on glassy carbon 23 or after electrode modification. 24 Otherwise, direct sulfite oxidation may be obtained at platinum, 25 gold, 26 glassy carbon, 27 and platinum-modified glassy carbon. 28 However, there still are challenges such as problems correlated with fouling of the electrode and high positive potential for oxidation of the sulfite.…”

“…28 However, there still are challenges such as problems correlated with fouling of the electrode and high positive potential for oxidation of the sulfite. [25][26][27] As a consenquence, a number of substances may interfere with the detection and measurement of the analyte.…”

Excellent Sulfur Dioxide Electrooxidation Performance and Good Stability on a Fe-N-Doped Carbon-Cladding Catalyst in H2SO4

“…[1][2][3][4][5] The reaction always takes place on anodic electrodes with direct oxidation of SO 2 under certain applied potential. [6][7][8] SO 2 anodic oxidation mostly perform on precious metal catalysts such as the gold, platinum, palladium, iridium and their alloys, [9][10][11][12][13][14] whose catalysis behaviors are extensively investigated and reported. [15][16][17][18] Platinum is the most commonly used catalyst for its excellent SO 2 catalytic activity and good stability in acid.…”