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 0.156 to 0.563 min, and the concentration of total organic halogen decreased from 59.2 to 8.6 μM. Through probe experiments, direct electron transfer and HO were ruled out as major contributors; transient absorption spectroscopy (TAS) and computational kinetic models revealed that trace Br triggers a shift in the dominant reactive species from Cl to Br, which plays a key role in pollutant removal. Both TAS and electron paramagnetic resonance identified signals unique to the phenoxyl and carbon-centered radicals in the Br-dominated system, indicating distinct reaction mechanisms compared to those involving Cl. Kinetic isotope experiments and density functional theory calculations confirmed that the interaction between Br and phenolic pollutants follows a hydrogen atom abstraction pathway, whereas Cl predominantly engages pollutants through radical adduct formation. These insights significantly enhance our understanding of bromine radical-involved oxidation processes and have crucial implications for optimizing electrochemical treatment systems for saline wastewater.
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http://dx.doi.org/10.1021/acs.est.4c02061 | DOI Listing |
Mar Pollut Bull
December 2024
Danish Offshore Technology Centre (DTU), - Elektrovej 375, 2800 Kgs. Lyngby, Denmark.
The offshore oilfields in the North Sea area are increasingly employed for projects beyond oil production, like carbon capture and storage (CCS). Still, the fossil fuel production from mature fields is significant. It has raised environmental concerns associated with discharging produced waters (PW) and drilling mud into the sea.
View Article and Find Full Text PDFWater Res
December 2024
School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510006, China. Electronic address:
Marine anammox bacteria-based Fe(II)-driven autotrophic denitratation and anammox (MFeADA) was investigated for nitrogen removal from saline wastewater for the first time. The study demonstrated that varying influent doses of Fe(II), which participate in the Fe cycle, significantly influenced nitrogen removal performance by altering the fate of nitrite. When 50 mg/L Fe(II) was added, the nitrogen removal was mainly performed by the anammox and Fe(II)-driven autotrophic denitratation (FeAD).
View Article and Find Full Text PDFJ Hazard Mater
December 2024
Key Laboratory of Materials Physics, Anhui Key Laboratory of Nanomaterials and Nanotechnology, Institute of Solid State Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, PR China; Science Island Branch of Graduate School, University of Science and Technology of China, Hefei 230026, PR China. Electronic address:
Recently, hybrid capacitive deionization (HCDI) has garnered significant attention for its potential in the selective extraction of cesium (Cs) from radioactive wastewater and salt lakes, which is crucial for resolving the supply-demand imbalance of cesium resources and eliminating radioactive contamination. However, developing HCDI electrodes capable of effectively separating and extracting Cs remains a significant challenge. In this work, we proposed an innovative strategy involving the doping of inactive metal ions to develop zinc-doped manganese hexacyanoferrate (ZMFC) as an HCDI cathode.
View Article and Find Full Text PDFWater Res
November 2024
Cavanilles Institute for Biodiversity and Evolutionary Biology, Universitat de València, E-46980 Paterna, València, Spain. Electronic address:
Shallow saline lakes in the La Mancha Húmeda Biosphere Reserve in Central Spain show diverse degrees of cultural and natural eutrophication, prompting urgent conservation measures. This study focuses on 17 representative lakes from the site to assess seasonal nutrient dynamics and their connection to plankton metabolism (photosynthesis and respiration) during two successive hydrological periods. Effect of environmental factors was evaluated on a combination of several response variables, demonstrating that source of the nutrient inputs (ranging from natural to anthropic) had the highest influence on the nutrients stoichiometry and metabolic rates.
View Article and Find Full Text PDFEnviron Technol
November 2024
School of Civil & Environmental Engineering and Geography Science, Ningbo University, Ningbo, People's Republic of China.
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