Effects of anodic potential and chloride ion on overall reactivity in electrochemical reactors designed for solar-powered wastewater treatment
SCIE
SCOPUS
- Title
- Effects of anodic potential and chloride ion on overall reactivity in electrochemical reactors designed for solar-powered wastewater treatment
- Authors
- CHO, KANGWOO; Yan Qu; Daejung Kwon; Hao Zhang; Clément A. Cid; Asghar Aryanfar; Michael R. Hoffmann
- Date Issued
- 2014-02-18
- Publisher
- AMER CHEMICAL SOC
- Abstract
- We have investigated electrochemical treatment of real domestic wastewater coupled with simultaneous production of molecular H-2 as useful byproduct. The electrolysis cells employ multilayer semiconductor anodes with electroactive bismuth-doped TiO2 functionalities and stainless steel cathodes. DC-powered laboratory-scale electrolysis experiments were performed under static anodic potentials (+2.2 or +3.0 V NHE) using domestic wastewater samples, with added chloride ion in variable concentrations. Greater than 95% reductions in chemical oxygen demand (COD) and ammonium ion were achieved within 6 h. In addition, we experimentally determined a decreasing overall reactivity of reactive chlorine species toward COD with an increasing chloride ion concentration under chlorine radicals (Cl center dot, Cl-2(-)center dot) generation at +3.0 V NHE. The current efficiency for COD removal was 12% with the lowest specific energy consumption of 96 kWh kgCOD(-1) at the cell voltage of near 4 V in 50 mM chloride. The current efficiency and energy efficiency for H-2 generation were calculated to range from 34 to 84% and 14 to 26%, respectively. The hydrogen comprised 35 to 60% by volume of evolved gases. The efficacy of our electrolysis cell was further demonstrated by a 20 L prototype reactor totally powered by a photovoltaic (PV) panel, which was shown to eliminate COD and total coliform bacteria in less than 4 h of treatment.
- Keywords
- MOLECULAR-HYDROGEN; OXIDE ELECTRODES; ORGANIC POLLUTANTS; ACTIVE CHLORINE; OXIDATION; ELECTROLYSIS; DEGRADATION; OXYGEN; PERCHLORATE; WASTEWATERS
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/40864
- DOI
- 10.1021/es404137u
- ISSN
- 0013-936X
- Article Type
- Article
- Citation
- ENVIRONMENTAL SCIENCE & TECHNOLOGY, vol. 48, no. 4, page. 2377 - 2384, 2014-02-18
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