Impacts of ammonium ion on triclinic birnessites towards the transformation of As(III)

Lu Jiang; Pingxiao Wu; Yijing Xu; Yihao Li; Meiqing Chen; Zubair Ahmed; Nengwu Zhu

doi:10.1016/j.envpol.2022.118815

Impacts of ammonium ion on triclinic birnessites towards the transformation of As(III)

Environ Pollut. 2022 Apr 1:298:118815. doi: 10.1016/j.envpol.2022.118815. Epub 2022 Jan 7.

Authors

Lu Jiang¹, Pingxiao Wu², Yijing Xu¹, Yihao Li¹, Meiqing Chen¹, Zubair Ahmed¹, Nengwu Zhu³

Affiliations

¹ School of Environment and Energy, South China University of Technology, Guangzhou, 510006, PR China.
² School of Environment and Energy, South China University of Technology, Guangzhou, 510006, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou, 510006, PR China; Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, Guangzhou, 510006, PR China; Guangdong Engineering and Technology Research Center for Environmental Nanomaterials, Guangzhou, 510006, PR China; Guangdong Provincial Engineering and Technology Research Center for Environmental Risk Prevention and Emergency Disposal, Guangzhou, 510006, PR China. Electronic address: pppxwu@scut.edu.cn.
³ School of Environment and Energy, South China University of Technology, Guangzhou, 510006, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou, 510006, PR China.

PMID: 35007679
DOI: 10.1016/j.envpol.2022.118815

Abstract

Triclinic birnessite (TB), a typical layered Mn oxide which is abundant naturally occurring minerals with a vital impact on the transformation of arsenite (As(III)) by adsorption and oxidation. As one of the most common critical metalloids, ammonium ion (NH₄⁺) universally coexists with birnessite in marine, sediments or groundwater where are contaminated with As(III). In this study, we investigated the impacts of NH₄⁺ on TB towards the transformation of As(III). Compared with the original TB (40.1%), the As(III) removal efficiencies of three different concentration (0.5 M, 1 M and 2 M) NH₄⁺ impressed triclinic birnessite (TB-0.5 N, TB-1N and TB-2N) are increased rapidly in the order of: TB-2N (80.4%) > TB-1N (75.8%) > TB-0.5 N (71.5%). In addition, TB-2N exhibited the highest initial oxidation rate of 0.0031 min^-1 which exceeds twice as much as this of TB (0.0014 min^-1). And TB-2N could reach the max oxidation efficiency when the As concentration is 0.08 mM. Due to two different mechanisms of As(III) oxidation on birnessites under acidic and alkaline conditions, TB-2N showed a higher removal efficiency than TB at pH 3.0, 5.0, 7.0 and 9.0. Hence, there are two main reasons for the advanced As(III) oxidation capacity of TB-2N. One is the improvement of the average oxidation state of Mn, the other is the increase of oxygen vacancy with the coexistence of NH₄⁺. Moreover, the larger specific surface area of TB-2N also contribute to enhancing As(III) oxidation capacity. This study holds a fundamental understanding of the behavior of triclinic birnessite which is coexisted with ammonium ion towards the transformation of As(III) in the environment.

Keywords: Ammonium; Arsenite; Birnessite; Transformation.

MeSH terms

Adsorption
Ammonium Compounds*
Manganese Compounds
Oxidation-Reduction
Oxides*

Substances

Ammonium Compounds
Manganese Compounds
Oxides
birnessite