Multi-functional photocatalytic fuel cell for simultaneous removal of organic pollutant and chromium (VI) accompanied with electricity production. (December 2019)

• Record Type: Journal Article
• Authors: Liu, Xiao-He; Xing, Zhong-Hang; Chen, Qing-Yun; Wang, Yun-Hai
• Is Part Of: Chemosphere. Volume 237(2019)
• Publication Date: 2019-12
• Subjects: Photocatalytic fuel cell -- Cr(VI) removal -- Organic pollutant removal -- Electricity production -- Stability; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2019.124457
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: It is of significant importance to realize the efficient wastewater treatment and energy recovery. This study presents a multi-functional photocatalytic fuel cell (PFC), which could reductively treat Cr(VI) contaminant and oxidatively degrade organic pollutant simultaneously along with electricity production in an economical strategy. TiO2 nanotube arrays (TNA) and graphite were used as photoanode and cathode in two separated chambers, respectively. The optimized PFC with open circuit voltage of 1.06 V, maximum power density of 1 W m −2 and short circuit current density of 3.7 A m −2 can be obtained by increasing Cr(VI) concentration and decreasing pH values in catholyte. Under optimized PFC conditions, more photogenerated electrons will be transferred to cathode for Cr(VI) reduction, and accelerating electron-hole separation in the photoanode, then facilitating the oxidation of organic pollutants on anode. More than 96.8% removal efficiency for 6.8 mM Cr(VI) with a cathodic efficiency of 95.1% can be achieved within 6 h. Methylene blue (MB), an organic model pollutant, is totally decolorized on photoanode, which is significantly improved compare to photocatalysis (61.5% removal efficiency). The stable cycle operation of this economical PFC has obtained owing to the stable and low cost materials of both photoanode and cathode. This work may provide an efficient and economical method to simultaneously remove two types of pollutants with electricity harvested in one cell. Graphical abstract: Image 1 Highlights: Simultaneous removal of two pollutants in one cell with electricity harvesting. Electricity output is promoted by Cr(VI) replacing O2 as main electron accepter. MB is totally decolorized and 96.8% Cr(VI) removal efficiency can be achieved. An economical and stable PFC for electricity production and wastewater treatment.