Insights into Electrochemical Nitrate Reduction to Nitrogen on Metal Catalysts for Wastewater Treatment

Environmental Science & Technology, Journal Year: 2025, Volume and Issue: 59(6), P. 3263 - 3275

Published: Jan. 6, 2025

Electrocatalytic nitrate reduction reaction (NO3RR) to harmless nitrogen (N2) presents a viable approach for purifying NO3–-contaminated wastewater, yet most current electrocatalysts predominantly produce ammonium/ammonia (NH4+/NH3) due challenges in facilitating N–N coupling. This study focuses on identifying metal catalysts that preferentially generate N2 and elucidating the mechanistic origins of their high selectivity. Our evaluation 16 commercially available metals reveals only Pb, Sn, In demonstrated substantial selectivity (79.3, 70.0, 57.0%, respectively, under conditions 6 h electrolysis, density 10 mA/cm2, an initial NO3–-N concentration 100 mg/L), while others largely favored NH4+ production. Comprehensive experimental theoretical analyses indicate NH4+-selective (e.g., Co) exhibited water activity enhances •H coverage, thereby promoting hydrogenation NO3– through hydrogen atom transfer mechanism. contrast, N2-selective catalysts, with lower activity, promoted formation N-containing intermediates, which likely undergo dimerization form via proton-coupled electron Enhancing adsorption was beneficial improve by competitively reducing coverage. findings highlight crucial role NO3RR performance offer rational design enhanced

Language: Английский

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Bilayer electrified-membrane with pair-atom tin catalysts for near-complete conversion of low concentration nitrate to dinitrogen

Nature Communications, Journal Year: 2025, Volume and Issue: 16(1)

Published: Jan. 28, 2025

Discharge of wastewater containing nitrate (NO3−) disrupts aquatic ecosystems even at low concentrations. However, selective and rapid reduction NO3− concentration to dinitrogen (N2) is technically challenging. Here, we present an electrified membrane (EM) loaded with Sn pair-atom catalysts for highly efficient N2 in a single-pass electrofiltration. The design facilitates coupling adsorbed N intermediates on adjacent atoms enhance selectivity, which challenging conventional fully-isolated single-atom catalyst design. EM ensures sufficient exposure the intensifies interaction through mass transfer enhancement provide more coupling. We further develop reduced titanium dioxide as anode generate free chlorines fully oxidizing residual ammonia (<1 mg-N L−1) N2. sequential cathode-to-anode electrofiltration realizes near-complete removal 10 L−1 ~100% selectivity water resident time order seconds. Our findings advance practical solution contamination authors report that mg-N/L during electro-filtration.

Language: Английский

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Electrochemical filtration for drinking water purification: A review on membrane materials, mechanisms and roles

Journal of Environmental Sciences, Journal Year: 2023, Volume and Issue: 141, P. 102 - 128

Published: July 4, 2023

Language: Английский

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Boosting Ammonium Oxidation in Wastewater by the BiOCl-Functionalized Anode

Environmental Science & Technology, Journal Year: 2023, Volume and Issue: 57(49), P. 20915 - 20928

Published: Nov. 28, 2023

Mixed metal oxide (MMO) anodes are commonly used for electrochlorination of ammonium (NH4+) in wastewater treatment, but they suffer from low efficiency due to inadequate chlorine generation at Cl– concentrations and sluggish reaction kinetics between free NH4+ under acidic pH conditions. To address this challenge, we develop a straightforward wet chemistry approach synthesize BiOCl-functionalized MMO electrodes using the as an efficient Ohmic contact electron transfer. Our study demonstrates that BiOCl@MMO anode outperforms pristine anode, exhibiting higher (24.6–60.0 mg Cl2 L–1), increased Faradaic (75.5 vs 31.0%), improved rate constant oxidation (2.41 0.76 L–1 min–1) 50 mM concentration. Characterization techniques including paramagnetic resonance situ transient absorption spectra confirm production radicals (Cl• Cl2•–) by BiOCl/MMO anode. Laser flash photolysis reveals significantly apparent second-order constants ((4.3–4.9) × 106 M–1 s–1 2.0–4.0) Cl•, compared undetectable Cl2•–, well slower (102 < 4.0) within same range, emphasizing significance Cl• enhancing oxidation. Mechanistic studies provide compelling evidence capacity BiOCl adsorption, facilitating evolution generation. Importantly, exhibits excellent long-term stability high catalytic activity NH4+-N removal real landfill leachate. These findings offer valuable insights into rational design improve electrocatalytic abatement, which holds great promise treatment applications.

Language: Английский

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Advancements in Single Atom Catalysts for Electrocatalytic Nitrate Reduction Reaction

ChemCatChem, Journal Year: 2024, Volume and Issue: 16(15)

Published: Jan. 23, 2024

Abstract Due to the urgent demand for nitrate wastewater treatment, quest an efficient and environmentally friendly treatment method has emerged as a new research focus. The utilization of single‐atom catalysts (SACs) in electrocatalytic reduction reaction (NO 3 RR) ammonia production is presently recognized effective strategy address pollution issues obtain high value‐added products. In this review, we summarized recent advancements NO RR based on SACs. This review includes comprehensive analysis identification structural determination techniques SACs, well mechanism over Furthermore, investigates impact regulating single atom structures RR, providing valuable insights enhancing efficiency. It explores application in‐situ technology real‐time monitoring control RR. Finally, perspectives challenges regarding SACs are presented. Overall, extensive offers researchers industry professionals field environmental catalysis.

Language: Английский

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