Efficient Removal of Nitrate in Neutral Solution Using Zero-Valent Al Activated by Soaking.

Autor: Dai YG; Energy Materials & Physics Group, Department of Physics, Shanghai University, Shanghai 200444, China.; Institute of Low-Dimensional Carbon and Device Physics, Shanghai University, Shanghai 200444, China., Guo XH; Energy Materials & Physics Group, Department of Physics, Shanghai University, Shanghai 200444, China.; Institute of Low-Dimensional Carbon and Device Physics, Shanghai University, Shanghai 200444, China., Ma GW; Energy Materials & Physics Group, Department of Physics, Shanghai University, Shanghai 200444, China.; Institute of Low-Dimensional Carbon and Device Physics, Shanghai University, Shanghai 200444, China., Gai WZ; College of Physics and Electronic Information & Henan Key Laboratory of Electromagnetic Transformation and Detection, Luoyang Normal University, Luoyang 471934, China., Deng ZY; Energy Materials & Physics Group, Department of Physics, Shanghai University, Shanghai 200444, China.; Institute of Low-Dimensional Carbon and Device Physics, Shanghai University, Shanghai 200444, China.
Jazyk: angličtina
Zdroj: ACS omega [ACS Omega] 2023 Jul 10; Vol. 8 (28), pp. 24922-24930. Date of Electronic Publication: 2023 Jul 10 (Print Publication: 2023).
DOI: 10.1021/acsomega.3c01347
Abstrakt: Nitrate is a contaminant widely found in surface water, and a high concentration of nitrate can pose a serious threat to human health. Zero-valent iron is widely used to reduce nitrate in aqueous solution, but an acidic condition is required. Zero-valent aluminum has a much lower redox potential ( E 0 (Al 3+ /Al 0 ) = -1.662 V) than zero-valent iron ( E 0 (Fe 2+ /Fe 0 ) = -0.44 V), making it a better choice for reduction of nitrate. However, a passive oxide film covering on Al surfaces inhibits its electron transfer. In this work, metal Al powder was activated by a soaking procedure in deionized water. It was found that nitrate in neutral solution can be efficiently and completely reduced by soaked Al, even if the concentration of nitrate-N was up to 100 mg L -1 . Using an optimal soaking time, the soaked Al can remove >90% of nitrate in aqueous solution within ∼2 h at 50 °C. Furthermore, the nitrate reduction efficiency increased with increasing reaction temperature and dosage of Al powder. After reaction, only ∼50% of pristine N content was left in the form of ammonia ions (NH 4 + ) in aqueous solution. Mechanism analyses showed that after soaking, Al particle surfaces were covered by a layer of loose and fine Al(OH) 3 grains, which can shorten the induction time for the beginning of the reaction between inner Al and outside ions or molecules. This is the reason why soaked Al has a high efficiency for nitrate removal. The present results indicate that soaking is an effective way to activate Al to remove nitrate in water.
Competing Interests: The authors declare no competing financial interest.
(© 2023 The Authors. Published by American Chemical Society.)
Databáze: MEDLINE
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