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Electrochemical Production of Hydrogen Coupled with the Oxidation of Arsenite

Kim, Jungwon and Kwon, Daejung and Kim, Kitae and Hoffmann, Michael R. (2014) Electrochemical Production of Hydrogen Coupled with the Oxidation of Arsenite. Environmental Science and Technology, 48 (3). pp. 2059-2066. ISSN 0013-936X. http://resolver.caltech.edu/CaltechAUTHORS:20140122-132149391

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Abstract

The production of hydrogen accompanied by the simultaneous oxidation of arsenite (As(III)) was achieved using an electrochemical system that employed a BiO_x–TiO_2 semiconductor anode and a stainless steel (SS) cathode in the presence of sodium chloride (NaCl) electrolyte. The production of H_2 was enhanced by the addition of As(III) during the course of water electrolysis. The synergistic effect of As(III) on H_2 production can be explained in terms of (1) the scavenging of reactive chlorine species (RCS), which inhibit the production of H_2 by competing with water molecules (or protons) for the electrons on the cathode, by As(III) and (2) the generation of protons, which are more favorably reduced on the cathode than water molecules, through the oxidation of As(III). The addition of 1.0 mM As(III) to the electrolyte at a constant cell voltage (E_(cell)) of 3.0 V enhanced the production of H2 by 12% even though the cell current (I_(cell)) was reduced by 5%. The net effect results in an increase in the energy efficiency (EE) for H_2 production (ΔEE) by 17.5%. Furthermore, the value ΔEE, which depended on As(III) concentration, also depended on the applied E_(cell). For example, the ΔEE increased with increasing As(III) concentration in the micromolar range but decreased as a function of E_(cell). This is attributed to the fact that the reactions between RCS and As(III) are influenced by both RCS concentration depending on E_(cell) and As(III) concentration in the solution. On the other hand, the ΔEE decreased with increasing As(III) concentration in the millimolar range due to the adsorption of As(V) generated from the oxidation of As(III) on the semiconductor anode. In comparison to the electrochemical oxidation of certain organic compounds (e.g., phenol, 4-chlorophenol, 2-chlorophenol, salicylic acid, catechol, maleic acid, oxalate, and urea), the ΔEE obtained during As(III) oxidation (17.5%) was higher than that observed during the oxidation of the above organic compounds (ΔEE = 3.0–15.3%) with the exception of phenol at 22.1%. The synergistic effect of As(III) on H_2 production shows that an energetic byproduct can be produced during the remediation of a significant inorganic pollutant.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://pubs.acs.org/doi/abs/10.1021/es4046814PublisherArticle
http://dx.doi.org/10.1021/es4046814DOIArticle
ORCID:
AuthorORCID
Hoffmann, Michael R.0000-0002-0432-6564
Additional Information:© 2014 American Chemical Society. Received: October 21, 2013. Revised: December 26, 2013. Accepted: January 3, 2014. Publication Date (Web): January 3, 2014. This research was supported by Hallym University Research Fund [HRF-201303-004(II)] and Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (NRF-2011-357-D00046 and NRF-2013R1A1A1007312). The authors declare no competing financial interest.
Funders:
Funding AgencyGrant Number
Hallym University Research FundHRF-201303-004(II)
National Research Foundation of Korea (NRF) Basic Science Research ProgramUNSPECIFIED
National Research Foundation of Korea (NRF)NRF-2011-357-D00046
National Research Foundation of Korea (NRF)NRF-2013R1A1A1007312
Ministry of Education, Science and Technology (MEST) of KoreaUNSPECIFIED
Record Number:CaltechAUTHORS:20140122-132149391
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20140122-132149391
Official Citation:Electrochemical Production of Hydrogen Coupled with the Oxidation of Arsenite Jungwon Kim, Daejung Kwon, Kitae Kim, and Michael R. Hoffmann Environmental Science & Technology 2014 48 (3), 2059-2066
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:43473
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:22 Jan 2014 21:51
Last Modified:09 Nov 2017 00:44

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