Electrochemical determination of chemical oxygen demand using Ti/TiO2 electrode.

Ge, Yongxian; Zhai, Yufang; Niu, Dun; Wang, Yuhong; Fernandez, Carlos; Ramakrishnappa, Thippeswamy; Hu, Xiaomin; Wang, Linshan

Abstract

To overcome the shortcomings of the conventional potassium dichromate method (PDM) for monitoring chemical oxygen demand (COD) of waters, many efforts have been made on developing quick and environment-friendly techniques. Among all alternatives, electrochemical (EC) techniques are very competitive due to their relatively simple devices and quickness. A number of electrodes have been fabricated to investigate electrochemical determination of COD. However, little work has been reported on Ti/TiO2 based electrode for this purpose. In the present work, Ti/Ti/TiO2 electrode was simply prepared by anodic oxidation of pure titanium. Aqueous solutions of potassium hydrogen phthalate and phenol were electrolyzed by chronocoulometry in a three-electrode system with Ti/Ti/TiO2 as working electrode (anode). Organic compounds were electrochemically oxidized on Ti/Ti/TiO2 electrode by hydroxyl radicals and the released electrons were recorded and transferred to currents. The electric currents were proportional to the COD values of the water samples being investigated. Based on data of COD values and corresponding currents, a linear regression equation was obtained for a certain kind of waste water. With the regression equation, current of an unknown water sample was transferred to its COD value. Conditions for the presented EC method were set up as cell voltage 2.0V v.s. SCE and pH 7.0. The linear range of COD was of about 25~530 mg/L. COD values of real waste water samples were measured by Ti/Ti/TiO2 electrode and the relative errors were all in the range of ±8% compared with data determined by conventional PDM. The electrochemicalmethodology was successfully applied to evaluate COD in waste water.

Citation

GE, Y., ZHAI, Y., NIU, D., WANG, Y., FERNANDEZ, C., RAMAKRISHNAPPA, T., HU, X. and WANG, L. 2016. Electrochemical determination of chemical oxygen demand using Ti/TiO2 electrode. International journal of electrochemical science [online], 11(12), pages 9812-9821. Available from: https://doi.org/10.20964/2016.12.05

• Journal Article Type: Article
• Acceptance Date: Sep 26, 2016
• Online Publication Date: Nov 10, 2016
• Publication Date: Dec 31, 2016
• Deposit Date: Feb 6, 2017
• Publicly Available Date: Feb 6, 2017
• Journal: International Journal of Electrochemical Science
• Print ISSN: 1452-3981
• Electronic ISSN: 1452-3981
• Publisher: Electrochemical Science Group
• Peer Reviewed: Peer Reviewed
• Volume: 11
• Issue: 12
• Pages: 9812-9821
• DOI: https://doi.org/10.20964/2016.12.05
• Keywords: Ti/TiO2 electrode; Anodic oxidation; Chemical oxygen demand; Chronocoulometry
• Public URL: http://hdl.handle.net/10059/2156