EXAFS study on arsenite(V) adsorption onto goethite and hematite

YANG Wang; LIN Jinru; YAO Hui; Yuanming Pan; Emilio Heredia; Roman Chernikov; ZHANG Danni; WANG Shaofeng; JIA Yongfeng

doi:10.11889/j.0253-3219.2021.hjs.44.120101

He jishu (Dec 2021)

EXAFS study on arsenite(V) adsorption onto goethite and hematite

YANG Wang,
LIN Jinru,
YAO Hui,
Yuanming Pan,
Emilio Heredia,
Roman Chernikov,
ZHANG Danni,
WANG Shaofeng,
JIA Yongfeng

Affiliations

YANG Wang: College of Applied Chemistry, Shenyang University of Chemical Technology, Shenyang 110142, China
LIN Jinru: Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
YAO Hui: College of Applied Chemistry, Shenyang University of Chemical Technology, Shenyang 110142, China
Yuanming Pan: Department of Geological Sciences, University of Saskatchewan, Saskatoon SK S7N 5E2, Canada
Emilio Heredia: Canadian Light Source, University of Saskatchewan, Saskatoon SK S7N 0X4, Canada
Roman Chernikov: Canadian Light Source, University of Saskatchewan, Saskatoon SK S7N 0X4, Canada
ZHANG Danni: Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
WANG Shaofeng: Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
JIA Yongfeng: Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China

DOI: https://doi.org/10.11889/j.0253-3219.2021.hjs.44.120101
Journal volume & issue: Vol. 44, no. 12
pp. 120101 – 120101

Abstract

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BackgroundArsenic (As) is one of the most toxic pollutants in the environment. Its adsorption on the surface of iron oxyhydr (oxides) is an important factor affecting its migration and transformation behavior. Goethite and hematite are ubiquitous in soil, groundwater and aquatic sediments. They all have the characteristics of small particle size, large specific surface area, and many active groups, thus can be used as adsorbents for As.PurposeThis study aims to investigate the behaviors of As(V) adsorbed on these two minerals, and determine its complex structures by extended X-ray absorption fine structure spectroscopy (EXAFS).MethodsFirst of all, adsorbents made from goethite and hematite were prepared for experimental measurement of As adsorption at different pH values and Fe/As molar ratios. Then the content of As in the solid phase after adsorption was measured by X-ray fluorescence spectrometer while the surface morphology of the adsorbent was characterized by scanning electron microscope (SEM). Finally, extended X-ray absorption fine structure spectroscopy (EXAFS), obtained at BioXAS beamline of Canadian synchrotron radiation source, was used to detect the coordination numbers of As and Fe adsorbed on the two adsorbents.ResultsThe results show that the adsorption capacity of these two adsorbents for As(V) under acidic pH is greater than that of the adsorbent under alkaline conditions. The adsorption capacity of the two adsorbents decreases with the increase of the Fe/As molar ratio. As(V) adsorption capacity of goethite is larger than that of hematite under the same adsorption pH and Fe/As molar ratio. The EXAFS data shows that the coordination numbers of As-Fe in both goethite and hematite are close to 1, and the distance of As-Fe in different samples is in the range of 3.29~3.31 Å.ConclusionsArsenic mainly forms monodentate-mononuclear complexes after adsorption on the surface of goethite and hematite, which is independent of the experimental pH values and the Fe/As molar ratios.

Published in He jishu

ISSN: 0253-3219 (Print)
Publisher: Science Press
Country of publisher: China
LCC subjects: Technology: Electrical engineering. Electronics. Nuclear engineering: Nuclear engineering. Atomic power
Website: https://www.hjs.sinap.ac.cn/

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