Reaction pathways and mechanisms of the electrochemical degradation of phenol on different electrodes

TY - JOUR

T1 - Reaction pathways and mechanisms of the electrochemical degradation of phenol on different electrodes

AU - Li, Xiao Yan

AU - Cui, Yu Hong

AU - Feng, Yu Jie

AU - Xie, Zhao Ming

AU - Gu, Ji Dong

N1 - Funding Information: This research was supported by a grant from the Research Grants Council of the Hong Kong SAR, China (HKU7008/01E), and a grant from the National Nature Science Foundation of China (50278022). The technical assistance of Mr. K.C.H. Wong is highly appreciated.

PY - 2005/5

Y1 - 2005/5

N2 - Laboratory experiments were carried out on the kinetics and pathways of the electrochemical (EC) degradation of phenol at three different types of anodes, Ti/SnO2-Sb, Ti/RuO2, and Pt. Although phenol was oxidised by all of the anodes at a current density of 20 mA/cm2 or a cell voltage of 4.6 V, there was a considerable difference between the three anode types in the effectiveness and performance of EC organic degradation. Phenol was readily mineralized at the Ti/SnO2-Sb anode, but its degradation was much slower at the Ti/RuO2 and Pt anodes. The analytical results of high-performance liquid chromatography (HPLC) and gas chromatography coupled with mass spectrometry (GC/MS) indicated that the intermediate products of EC phenol degradation, including benzoquinone and organic acids, were subsequently oxidised rapidly by the Ti/SnO2-Sb anode, but accumulated in the cells of Ti/RuO2 and Pt. There was also a formation of dark-coloured polymeric compounds and precipitates in the solutions electrolyzed by the Ti/RuO2 and Pt anodes, which was not observed for the Ti/SnO 2-Sb cells. It is argued that anodic property not only affects the reaction kinetics of various steps of EC organic oxidation, but also alters the pathway of phenol electrolysis. Favourable surface treatment, such as the SnO2-Sb coating, provides the anode with an apparent catalytic function for rapid organic oxidation that is probably brought about by hydroxyl radicals generated from anodic water electrolysis.

AB - Laboratory experiments were carried out on the kinetics and pathways of the electrochemical (EC) degradation of phenol at three different types of anodes, Ti/SnO2-Sb, Ti/RuO2, and Pt. Although phenol was oxidised by all of the anodes at a current density of 20 mA/cm2 or a cell voltage of 4.6 V, there was a considerable difference between the three anode types in the effectiveness and performance of EC organic degradation. Phenol was readily mineralized at the Ti/SnO2-Sb anode, but its degradation was much slower at the Ti/RuO2 and Pt anodes. The analytical results of high-performance liquid chromatography (HPLC) and gas chromatography coupled with mass spectrometry (GC/MS) indicated that the intermediate products of EC phenol degradation, including benzoquinone and organic acids, were subsequently oxidised rapidly by the Ti/SnO2-Sb anode, but accumulated in the cells of Ti/RuO2 and Pt. There was also a formation of dark-coloured polymeric compounds and precipitates in the solutions electrolyzed by the Ti/RuO2 and Pt anodes, which was not observed for the Ti/SnO 2-Sb cells. It is argued that anodic property not only affects the reaction kinetics of various steps of EC organic oxidation, but also alters the pathway of phenol electrolysis. Favourable surface treatment, such as the SnO2-Sb coating, provides the anode with an apparent catalytic function for rapid organic oxidation that is probably brought about by hydroxyl radicals generated from anodic water electrolysis.

KW - Anode

KW - Electro-oxidation

KW - Electrochemistry

KW - Free radicals

KW - Phenol

KW - Wastewater treatment

UR - http://www.scopus.com/inward/record.url?scp=20344396124&partnerID=8YFLogxK

U2 - 10.1016/j.watres.2005.02.021

DO - 10.1016/j.watres.2005.02.021

M3 - 文章

C2 - 15882890

AN - SCOPUS:20344396124

SN - 0043-1354

VL - 39

SP - 1972

EP - 1981

JO - Water Research

JF - Water Research

IS - 10

ER -