Optimizing the removal of nitrate from aqueous solutions via reduced graphite oxide–supported nZVI: synthesis, characterization, kinetics, and reduction mechanism
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Graphene has been considered an ideal absorbent and excellent carrier for nanoparticles. Reduced graphite oxide (rGO)–supported nanoscale zero-valent iron (nZVI@rGO) is an effective material for removing nitrate from water. nZVI@rGO nanocomposites were prepared by a liquid-phase reduction method and then applied for nitrate-nitrogen (NO3−-N) removal in aqueous solution under anaerobic conditions. The experimental results showed that the stability and activity of the nZVI@rGO nanocomposites were enhanced compared with those of nZVI. The influence of the reaction conditions, including the initial concentration of NO3−-N, coexisting anions, initial pH of the solution, and water temperature, on NO3−-N removal was also investigated by batch experiments. In a neutral or slightly alkaline environment, 90% of NO3−-N at a concentration less than 50 mg/L could be removed within 1 h, and nitrogen production was approximately 15%. The process of NO3−-N removal by nZVI@rGO fits well with different reaction kinetics. In addition, magnetite was the main oxidation product. RGO-supported nZVI might become a promising filler in the permeable reactive barrier process for groundwater remediation.
KeywordsNitrate Reduced graphite oxide Denitrification nZVI@rGO Groundwater remediation
This work was supported by the National Natural Science Foundation of China (41772264, 51408074), the Applied Basic Research Programs of Science and Technology Foundation of Sichuan Province (18YYJC1745), and the Research Fund of State Key Laboratory of Geohazard Prevention and Geoenvironment Protection (SKLGP2019Z009). Prof. Chu is supported by the Shenzhen Basic Research Funding Scheme 2018 (JCYJ20170818105109311).
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Conflict of interest
The authors declare that they have no conflict of interest.
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