Arsenite and arsenate binding to ferrihydrite organo-mineral coprecipitate: Implications for arsenic mobility and fate in natural environments

Chemosphere
Qin XueHuihui Du

Abstract

Arsenic mobility in soils, sediments and groundwater systems is strongly controlled by adsorption occurring at iron oxide/water interfaces, and the extent of this adsorption may be influenced by the presence of natural organic matter (NOM). This study aims to investigate the adsorption of As(III) and As(V) onto coprecipitates made with ferrihydrite (Fh) and humic acid (HA) with two organic carbon (OC) loadings of 5 and 15 wt% OC. We show that the coprecipitation of HA with Fh can significantly reduce the retention of both As(III) and As(V) over a wide pH range (4-11), and with increased OC loading, there is reduced arsenic adsorption. On pure Fh, As(III) is adsorbed to a greater extent than As(V) at pH > 6.5 (the crossover pH), whereas the crossover pH shifts to more acidic pH in the presence of HA, implying that the binding of As(III) is more favorable than As(V) in the presence of NOM. Both As(III) and As(V) are complexed with the ferric hydroxyl functional groups, and no ternary Fh-HA-As complexes are detected. We observe that ∼40% of the adsorbed As(III) is oxidized to As(V) on pure Fh, compared to only ∼29% of As(III) oxidation on the Fh-HA coprecipitate, indicating that NOM hinders As(III) oxidation on iron (hydr)oxide. T...Continue Reading

Citations

Feb 6, 2020·International Journal of Environmental Research and Public Health·Yi-Min WangAnd Xu-Yin Yuan
Sep 18, 2020·Science and Technology of Advanced Materials·Mbolantenaina Rakotomalala RobinsonMartine Mallet
Jul 30, 2020·Environmental Science and Pollution Research International·Yulong WangYongfeng Jia
Nov 21, 2020·Journal of Nanoscience and Nanotechnology·Changsheng YueYanshan Cui
Oct 14, 2020·Journal of Hazardous Materials·Anthony BeauvoisMélanie Davranche
Jul 13, 2021·Journal of Hazardous Materials·Taiane G F SouzaVirginia S T Ciminelli
Oct 29, 2021·Journal of Toxicology and Environmental Health. Part B, Critical Reviews·Tyler D SowersKaren D Bradham
Nov 12, 2021·Environmental Science and Pollution Research International·Zhuanjun ZhaoShuqi Guan

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