Effect of calcium and phosphorus on ammonium and nitrate nitrogen adsorption onto iron (hydr)oxides surfaces: CD-MUSIC model and DFT computation

被引：0

作者：

Jia M. ^{[1
]}

Ma J. ^{[2
]}

Zhou Q. ^{[3
]}

Liu L. ^{[4
]}

Jie X. ^{[1
]}

Liu H. ^{[1
]}

Qin S. ^{[1
]}

Li C. ^{[1
]}

Sui F. ^{[1
]}

Fu H. ^{[1
]}

Xie H. ^{[5
]}

Wang L. ^{[1
]}

Zhao P. ^{[1
]}

机构：

[1] College of Resources and Environment, Henan Agricultural University, Henan, Zhengzhou

[2] Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin

[3] College of Horticulture, Henan Agricultural University, Henan, Zhengzhou

[4] Agricultural Ecology and Resource Protection Station, Agriculture and Rural Bureau, Henan, Xinxiang

[5] Hangzhou Yanqu Information Technology Co., Ltd, Zhejiang, Hangzhou

来源：

Chemosphere | 2024年 / 357卷

基金：

中国国家自然科学基金;

关键词：

Ammonium nitrogen; CD-MUSIC model; DFT calculation; Iron (hydr)oxides; Nitrate nitrogen;

D O I：

10.1016/j.chemosphere.2024.142070

中图分类号：

学科分类号：

摘要：

Calcium (Ca2+) and phosphorous (PO43−) significantly influence the form and effectiveness of nitrogen (N), however, the precise mechanisms governing the adsorption of ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3−-N) are still lacking. This study employed batch adsorption experiments, charge distribution and multi-site complexation (CD-MUSIC) models and density functional theory (DFT) calculations to elucidate the mechanism by which Ca2+ and PO43− affect the adsorption of NH4+-N and NO3−-N on the goethite (GT) surface. The results showed that the adsorption of NH4+-N on the GT exhibited an initial increase followed by a decrease as pH increased, peaking at a pH of 8.5. Conversely, the adsorption of NO3−-N decreased with rising pH. According to the CD-MUSIC model, Ca2+ minimally affected the NH4+-N adsorption on the GT but enhanced NO3−-N adsorption via electrostatic interaction, promoting the adsorption of ≡FeOH-NO3− and ≡Fe3O-NO3− species. Similarly, PO43− inhibited the adsorption of ≡FeOH-NO3− and ≡Fe3O-NO3− species. However, PO43− boosted NH4+-N adsorption by facilitating the formation of ≡Fe3O-NH4+ via electrostatic interaction and site competition. DFT calculations indicates that although bidentate phosphate (BP) was beneficial to stabilize NH4+-N than monodentate phosphate (SP), SP-NH4+ was the main adsorption configuration at pH 5.5–9.5 owing the prevalence of SP on the GT surface under site competition of NH4+-N. The results of CD-MUSIC model and DFT calculation were verified mutually, and provide novel insights into the mechanisms underlying N fixation and migration in soil. © 2024 Elsevier Ltd

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