Ammonia nitrogen adsorption by different aquifer media: An experimental trial for nitrogen removal from groundwater

Abstract

Groundwater resources in North China are scarce, and nitrogen pollution, especially ammonia nitrogen pollution, in groundwater is a severe environmental challenge for this area. In this context, the effects of differentaquifer media on ammonia nitrogen adsorption in Hutuo river plain, north China were investigated in the study. In particular, the aim of this study was to investigate the influence of Eh, clay particle and organic material content on ammonia nitrogen adsorption. The study found that Eh affected the migration and transformation of NH₄⁺-N in aquifer media. When the clay particle content was less than or equal to 14%, the NH₄⁺-N adsorption reached the equilibrium state in 210 min. The adsorption was the maximum when the clay content was 14% in the study. The NH₄⁺-N adsorption of by three sand types increased with the increase of clay content. Meanwhile, the concentration of NO₂⁻-N and NO₃⁻-N increased, though the change was not significant. The increase in the organic matter content enhanced the oxidation of the medium, and pH value continued to decline, leading to H⁺ and NH₄⁺ forming a competitive relationship in the solution. However, the NH₄⁺-N adsorption capacity gradually increased as the organic matter consisting of more cation adsorption sites.

Keywords:

• Ammonia nitrogen
• Eh
• clay particle
• organic material
• adsorption

Acknowledgment

The authors are grateful to the anonymous reviewers and the editors who helped us in improving the quality of the paper.

Additional information

Funding

This research is supported by the Open fund of the Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region of the Ministry of Education (300102299505 and 300102290501) and Natural Science Foundation of Education Department in Heibei Province (D2019403194).