Carbon Fiber-Based Flow-Through Electrode System (FES) for Water Disinfection via Direct Oxidation Mechanism with a Sequential Reduction–Oxidation Process

Flow-through configuration for electrochemical disinfection is considered as a promising approach to minimize the formation of toxic byproducts and energy consumption via the enhanced convective mass transport as compared with conventional flow-by one. Under this hydrodynamic condition, it is essent...

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Bibliographic Details
Published in:Environmental science & technology 2019-03, Vol.53 (6), p.3238-3249
Main Authors: Liu, Hai, Ni, Xin-Ye, Huo, Zheng-Yang, Peng, Lu, Li, Guo-Qiang, Wang, Chun, Wu, Yin-Hu, Hu, Hong-Ying
Format: Article
Language:English
Subjects:
Anode effect
Anodizing
Byproducts
Carbon fibers
Cathodes
Deactivation
Disinfection
E coli
Electrochemistry
Electrodes
Energy conservation
Energy consumption
Energy efficiency
Escherichia coli
Flow
Inactivation
Mass transport
Oxidation
Oxidation process
Portable equipment
Pretreatment
Reduction
Water treatment
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Summary:Flow-through configuration for electrochemical disinfection is considered as a promising approach to minimize the formation of toxic byproducts and energy consumption via the enhanced convective mass transport as compared with conventional flow-by one. Under this hydrodynamic condition, it is essential to ascertain the effect of sequential electro-redox processes with the cathode/anode then anode/cathode arrangements on disinfection performance. Here, carbon fiber felt (CFF) was utilized to construct two flow-through electrode systems (FESs) with sequential reduction–oxidation (cathode-anode) or oxidation–reduction (anode–cathode) processes to systematically compare their disinfection performance toward a model Escherichia coli (E. coli) pathogen. In-situ sampling and live/dead backlight staining experiments revealed that E. coli inactivation mainly occurred on anode via an adsorption-inactivation-desorption process. In reduction–oxidation system, after the cathode-pretreatment, bulk solution pH increased significantly, leading to the negative charge of E. coli cells. Hence, E. coli cells were adsorbed and inactivated easily on the subsequent anode, finally resulting in its much better disinfection performance and energy efficiency than the oxidation–reduction system. Application of 3.0 V resulted in ∼6.5 log E. coli removal at 1500 L m–2 h–1 (50 mL min–1), suggesting that portable devices can be designed from CFF-based FES with potential application for point-of-use water disinfection.
ISSN:0013-936X
1520-5851
DOI:10.1021/acs.est.8b07297