Flexible biological arsenite oxidation utilizing NOx and O2 as alternative electron acceptors

Wang, Jie; Wan, Junfeng; Wu, Zihao; Li, Hongli; Li, Haisong; Dagot, Christophe; Wang, Yan

doi:10.1016/j.chemosphere.2017.03.044

Cited by 7 publications

(1 citation statement)

References 35 publications

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“…The pH-dependent iAs(III) oxidation was consistent with prior findings that microbially mediated iAs(III) oxidations had maximum oxidation rate or reached maximum extent at the near neutral range of pH (7 ± 0.2), the oxidation rate or oxidation amount decreased with the decreasing pH. 62,63 Oxidation of Fe(II) by oxygen in air was also highly pH dependent. 15 Unlike the highly sulfidic water to which the addition of strong acids caused instantaneous precipitation of poorly crystalline orpiment, and thereby lowering the total As, 64,65 no loss was observed in all of our groundwater samples preserved with strong acids due to the low sulfide concentration (Tables S2−S4).…”

Section: Precipitation Of Fe-oxides and Recrystallizationsupporting

confidence: 88%

Large Quantity EDTA Addition and Cold Storage in Dark Recommended for Preserving Inorganic Arsenic Speciation in Reducing Groundwater

Duan,

Liu,

Yang

et al. 2024

ACS EST Water

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Analysis of inorganic arsenic (iAs) species, arsenite (iAs(III)) and arsenate (iAs(V)), is recommended by authorities to select treatment technologies for noncompliant domestic well water. However, the effectiveness of various preservation methods for iAs species, including those recommended by regulatory authorities, varies with the added preservatives on-site, groundwater chemistry, and storage conditions. Here, 14 preservation methods, which include three strong acids, a range of concentrations of ethylene diamine tetraacetic acid disodium salt (EDTA) and acetic acid (HAc), three storage temperatures, and two kinds of sample bottles, were tested with 62 groundwaters spanning a wide range of chemical compositions from multiple aquifers in northwestern and southern China. Addition of EDTA to a final concentration of 20 mmol/L and storage in opaque bottles and in the dark at 4 °C preserved iAs species up to 60 days. Preservation was achieved through forming Fe-EDTA and Mn-EDTA complexes accompanied by lowering of the pH from 7.0 ± 0.5 to 5.2 ± 0.4 and eliminating photooxidation. Users are recommended to start with the best performing protocol involving adding EDTA to 20 mmol/L on-site, adjusting the EDTA dose considering the initial Fe and Mn concentrations, and final pH. Regulatory authorities are urged to examine iAs preservation protocols in their standard methods for speciation analysis.

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