Adsorption of nitrate from interflow by the Mg/Fe calcined layered double hydroxides

Liquan Chu; Chaojie Zhang; Jing Yu; Xu Sun; Xuefei Zhou; Yalie Zhang

doi:10.2166/wst.2022.224

Water Science and Technology (Aug 2022)

Adsorption of nitrate from interflow by the Mg/Fe calcined layered double hydroxides

Liquan Chu,
Chaojie Zhang,
Jing Yu,
Xu Sun,
Xuefei Zhou,
Yalie Zhang

Affiliations

Liquan Chu: State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China
Chaojie Zhang: State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China
Jing Yu: State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China
Xu Sun: State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China
Xuefei Zhou: State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China
Yalie Zhang: State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China

DOI: https://doi.org/10.2166/wst.2022.224
Journal volume & issue: Vol. 86, no. 3
pp. 511 – 529

Abstract

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Nitrate loss in interflow caused serious nitrate pollution of neighboring water bodies in the purple soil region of China's Sichuan Province. In this study, Mg/Fe(Al)-calcined layered double hydroxides (Mg/Fe(Al)-CLDHs) with varied Mg/Fe(Al) ratios were synthesized for nitrate removal from interflow, and 3:1 Mg/Fe CLDH exhibited the best adsorption performance. The effects of initial pH, adsorbent dosage and co-existing anions on the adsorption performance were investigated by batch experiments. The best-fitting kinetic and isothermal models for nitrate adsorption were the pseudo-second-order model and Freundlich model, respectively, indicating that the adsorption process was a physical-chemical multilayer process. The maximum adsorption capacity of nitrate was 73.36 mg/g, which was higher than that of many other commonly used adsorbents. The adsorbents were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscope (TEM) and Brunauer–Emmett–Teller (BET) techniques, and the XRD and FT-IR results revealed that the adsorption mechanism involved original layered structure reconstruction and ion-exchange interaction. Under the coexistence of SO42− and Cl−, 75.63% nitrate in interflow could be removed after 6 h of adsorption. Overall, the synthesized Mg/Fe CLDH is an effective and low-cost nitrate adsorbent for in-situ nitrate removal. HIGHLIGHTS Mg/Fe calcined layered double hydroxides were synthesized for nitrate adsorptive removal.; The best-fitting kinetic model and isothermal model for nitrate adsorption were the pseudo-second-order model and Freundlich model, respectively.; The adsorption mechanism involved original layered structure reconstruction and ion-exchange interaction.; 75.63% nitrate was removed from interflow water after 6 h of adsorption.;

Published in Water Science and Technology

ISSN: 0273-1223 (Print); 1996-9732 (Online)
Publisher: IWA Publishing
Country of publisher: United Kingdom
LCC subjects: Technology: Environmental technology. Sanitary engineering
Website: https://iwaponline.com/wst

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