1. Silica-coated nano zero-valent iron as a slow-release electron donor for sustained enhancement of aerobic denitrification in oligotrophic source water: Performance and mechanism.
- Author
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Wu T, Li J, Cao R, Chen X, Wang J, Cheng Y, Wang B, Huang T, and Wen G
- Subjects
- Water Pollutants, Chemical, Aerobiosis, Water Purification methods, Nitrogen, Nitrates, Denitrification, Silicon Dioxide chemistry, Iron chemistry
- Abstract
Limited organic carbon in drinking water constrains the removal of nitrate‑nitrogen (NO
3 - -N) via aerobic denitrification. This paper reports the use of silica-coated nano zero-valent iron (nZVI@SiO2 ) as a stable and sustainable electron donor to enhance aerobic denitrification. The nZVI@SiO2 , synthesized via a one-step method, was resistant to oxidation and exhibited excellent stability. In conjunction with aerobic denitrifying bacteria, nZVI@SiO2 achieved NO3 - -N and total nitrogen TN removal efficiencies of 90.64 % and 80.94 %, respectively. This represents an increase of 24.15 % in the efficiency of TN removal compared with that of the nZVI system. The activity of the nZVI system diminished gradually after just three cycles, whereas nZVI@SiO2 maintained NO3 - -N and TN removal efficiencies of 89.33 % and 78.08 %, respectively, after four cycles, respectively, indicating its sustainable ability to enhance aerobic denitrification. Cyclic voltammetry and electrochemical impedance spectroscopy demonstrated enhanced electron transfer efficiency of nZVI@SiO2 . Furthermore, nZVI@SiO2 significantly promoted the activity of the electron transfer system, ATP levels, nitrate/nitrite reductase activity, contents of complexes I and III, and extracellular polymeric substances. nZVI@SiO2 significantly enhanced electron generation, transfer, and consumption during biological denitrification by functioning as both an electron donor and mediator. The findings implicate nZVI@SiO2 as a means to enhance nitrogen removal by aerobic denitrifying microorganisms in oligotrophic water via sustained donation of electrons., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)- Published
- 2024
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