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Electrochemically and Bioelectrochemically Induced Ammonium Recovery
Published on: January 22, 2015
Optimization of the cathode material for nitrate removal by a paired electrolysis process
David Reyter1, Daniel Bélanger, Lionel Roué
1INRS Energie, Matériaux et Télécommunications, 1650 bd. Lionel-Boulet, Varennes (QC), J3X 1S2, Canada.
Journal of Hazardous Materials
|June 28, 2011
Summary
Cupronickel electrodes efficiently convert nitrate to nitrogen in paired electrolysis. Cu(70)Ni(30) and Cu(90)Ni(10) show excellent corrosion resistance and high energy efficiency for nitrate removal.
Area of Science:
- Electrochemistry
- Environmental Engineering
- Materials Science
Background:
- Nitrate contamination in water poses significant environmental and health risks.
- Effective methods for nitrate removal are crucial for water treatment.
- Electrochemical reduction offers a promising pathway for nitrate conversion.
Purpose of the Study:
- To evaluate nickel (Ni), copper (Cu), and cupronickel alloys (Cu(90)Ni(10), Cu(70)Ni(30)) as cathode materials for nitrate electroreduction.
- To assess the corrosion resistance of these materials in challenging water matrices.
- To determine the efficiency and selectivity of nitrate conversion to nitrogen gas (N2).
Main Methods:
- Corrosion measurements were conducted on Ni, Cu, Cu(90)Ni(10), and Cu(70)Ni(30) electrodes.
- Nitrate electroreduction experiments were performed using an undivided flow-through electrolyzer.
- Paired electrolysis experiments were used to confirm nitrate conversion to nitrogen.
Main Results:
- Ni and Cu(70)Ni(30) electrodes exhibited superior corrosion resistance compared to Cu and Cu(90)Ni(10) in the presence of chloride, nitrate, and ammonia.
- Cupronickel electrodes demonstrated high efficiency (100% selectivity) for reducing nitrate to ammonia.
- Cu(70)Ni(30) and Cu(90)Ni(10) cathodes effectively converted nitrate to nitrogen, reducing concentrations from 620ppm to <50ppm with 100% N2 selectivity.
- Energy consumption was significantly lower for cupronickel cathodes (20 kWh/kg NO3-) compared to pure Cu (∼35 kWh/kg NO3-) and Ni (∼220 kWh/kg NO3-).
Conclusions:
- Cupronickel alloys, particularly Cu(70)Ni(30), are highly effective and corrosion-resistant cathode materials for electrochemical nitrate conversion to nitrogen.
- This electrochemical approach offers an energy-efficient solution for removing nitrate contaminants from water.
- The study highlights the potential of tailored alloy design for advanced water treatment applications.
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