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

Electrocatalytic nitrate reduction reaction (NORR) to harmless nitrogen (N) presents a viable approach for purifying NO-contaminated wastewater, yet most current electrocatalysts predominantly produce ammonium/ammonia (NH/NH) due to challenges in facilitating N-N coupling. This study focuses on identifying metal catalysts that preferentially generate N and elucidating the mechanistic origins of their high selectivity. Our evaluation of 16 commercially available metals reveals that only Pb, Sn, and In demonstrated substantial N selectivity (79.

Overlooked Roles and Transformation of Carbon-Centered Radicals Produced from Natural Organic Matter in a Thermally Activated Persulfate System.

The presence and induced secondary reactions of natural organic matter (NOM) significantly affect the remediation efficacy of in situ chemical oxidation (ISCO) systems. However, it remains unclear how this process relates to organic radicals generated from reactions between the NOM and oxidants. The study, for the first time, reported the vital roles and transformation pathways of carbon-centered radicals (CCR) derived from NOM in activated persulfate (PS) systems.

An Anti-Scaling Strategy for Electrochemical Wastewater Treatment: Leveraging Tip-Enhanced Electric Fields.

Electrode scaling poses a critical barrier to the adoption of electrochemical processes in wastewater treatment, primarily due to electrode inactivation and increased internal reactor resistance. We introduce an antiscaling strategy using tip-enhanced electric fields to redirect scale-forming compounds (e.g.

Trace Br Inhibits Halogenated Byproduct Formation in Saline Wastewater Electrochemical Treatment.

The electrochemical technology provides a practical and viable solution to the global water scarcity issue, but it has an inherent challenge of generating toxic halogenated byproducts in treatment of saline wastewater. Our study reveals an unexpected discovery: the presence of a trace amount of Br not only enhanced the electrochemical oxidation of organic compounds with electron-rich groups but also significantly reduced the formation of halogenated byproducts. For example, in the presence of 20 μM Br, the oxidation rate of phenol increased from 0.

In Situ Reconstruction of Metal Oxide Cathodes for Ammonium Generation from High-Strength Nitrate Wastewater: Elucidating the Role of the Substrate in the Performance of CoO.

In situ electrochemical reconstruction is important for transition metal oxides explored as electrocatalysts for electrochemical nitrate reduction reactions (ENRRs). Herein, we report substantial performance enhancement of ammonium generation on Co, Fe, Ni, Cu, Ti, and W oxide-based cathodes upon reconstruction. Among them, the performance of a freestanding ER-CoO/CF (CoO grown on Co foil subjected to electrochemical reduction) cathode was superior to its unreconstructed counterpart and other cathodes; e.

Reactive species conversion into O promotes substantial inhibition of chlorinated byproduct formation during electrooxidation of phenols in Cl-laden wastewater.

The generation of chlorinated byproducts during the electrochemical oxidation (EO) of Cl-laden wastewater is a significant concern. We aim to propose a concept of converting reactive species (e.g.

Single-Atom Cu Catalysts for Enhanced Electrocatalytic Nitrate Reduction with Significant Alleviation of Nitrite Production.

Metallic Cu is a well-known electrocatalyst for nitrate reduction reaction (NO RR), but it suffers from relatively low activity, poor stability, and inducing nitrite accumulation during the long-term operation. Herein, it is found that Cu catalysts minimized at the single-atom level can overcome the limitations of bulk materials in NO RR. A metal-nitrogen-carbon (M-N-C) electrocatalyst composed of carbon nanosheets embedding isolated copper atoms coordinated with N, Cu-N-C-800, is synthesized by pyrolysis of a Cu-based metal-organic framework at 800 °C.

Fe/HClO Reaction Produces FeO: An Enhanced Advanced Oxidation Process.

The reaction between Fe and HClO constitutes a promising advanced oxidation process (AOP) for removing pollutants from wastewater, and OH has been considered the dominant reactive oxidant despite limited evidence for this. Herein, we demonstrate that the Fe/HClO reaction enables the production of FeO rather than OH in acid medium, a finding that is strongly supported by multiple lines of evidence. Both X-ray absorption near-edge structure spectroscopic tests and Mössbauer spectroscopic tests confirmed the appearance of FeO as the reactive intermediate in the reaction between Fe and HClO.

Comparative studies on catalytic mechanisms for natural chalcopyrite-induced Fenton oxidation: Effect of chalcopyrite type.

The type of chalcopyrite plays a key role in determining its physicochemical properties. In this study, we present a systematic comparative study on the use of p- and n-type chalcopyrite (Cpy A and Cpy B, respectively) as Fenton catalysts for wastewater treatment. Experimental results showed that 60% of AO7 removal could be achieved in 30 min at a natural pH when HO was activated by Cpy A.

Highly active and durable carbon electrocatalyst for nitrate reduction reaction.

The development of a new class of carbon electrocatalysts for nitrate reduction reaction (NRR) that have high activity and durability is extremely important, as currently reported metallic electrocatalysts show a main drawback of low stability owing to leaching and oxidation. Herein, we demonstrate that a unique N-doped graphitic carbon-encapsulated iron nanoparticles can be utilized as a promising NRR electrocatalyst. The resulting Fe(20%)@N-C achieves a better nitrate removal proportion of 83.