Humic acid promotes arsenopyrite bio-oxidation and arsenic immobilization

Zhang, Duo-rui; Chen, Hongrui; Xia, Jin-lan; Nie, Zuoren; Fan, Xiaolu; Liu, Hongchang; Zheng, Lei; Zhang, Lijuan; Yang, Heng

doi:10.1016/j.jhazmat.2019.121359

Cited by 49 publications

(12 citation statements)

References 43 publications

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“…The promotion of bacterial growth at the bottom of the columns with the addition of As(III) was probably due to the formation of Fe/As/S-containing precipitates, FeAsO 4 ⋅2H 2 O, and jarosites ( Figures 4–7 ), which can adsorb to or coprecipitate with As species. These processes could significantly mitigate the harmfulness of As(III) and reduce the Fe 3+ concentration and thus mitigate the inhibited feedback of Fe(III) to the ferrous-oxidizing enzyme activity ( Hare et al, 2020 ; Zhang et al, 2020 ). Moreover, the cells detected at the bottom showed somewhat As adsorption according to the results of FT-IR ( Supplementary Figure 8 ), which could also reduce As harmfulness and thus favor cell growth ( Zhang et al, 2021 ).…”

Section: Discussionmentioning

confidence: 99%

Correlation Between Fe/S/As Speciation Transformation and Depth Distribution of Acidithiobacillus ferrooxidans and Acidiphilium acidophilum in Simulated Acidic Water Column

et al. 2022

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It is well known that speciation transformations of As(III) vs. As(V) in acid mine drainage (AMD) are mainly driven by microbially mediated redox reactions of Fe and S. However, these processes are rarely investigated. In this study, columns containing mine water were inoculated with two typical acidophilic Fe/S-oxidizing/reducing bacteria [the chemoautotrophic Acidithiobacillus (At.) ferrooxidans and the heterotrophic Acidiphilium (Aph.) acidophilum], and three typical energy substrates (Fe2+, S0, and glucose) and two concentrations of As(III) (2.0 and 4.5 mM) were added. The correlation between Fe/S/As speciation transformation and bacterial depth distribution at three different depths, i.e., 15, 55, and 105 cm from the top of the columns, was comparatively investigated. The results show that the cell growth at the top and in the middle of the columns was much more significantly inhibited by the additions of As(III) than at the bottom, where the cell growth was promoted even on days 24–44. At. ferrooxidans dominated over Aph. acidophilum in most samples collected from the three depths, but the elevated proportions of Aph. acidophilum were observed in the top and bottom column samples when 4.5 mM As(III) was added. Fe2+ bio-oxidation and Fe3+ reduction coupled to As(III) oxidation occurred for all three column depths. At the column top surfaces, jarosites were formed, and the addition of As(III) could lead to the formation of the amorphous FeAsO4⋅2H2O. Furthermore, the higher As(III) concentration could inhibit Fe2+ bio-oxidation and the formation of FeAsO4⋅2H2O and jarosites. S oxidation coupled to Fe3+ reduction occurred at the bottom of the columns, with the formations of FeAsO4⋅2H2O precipitate and S intermediates. The formed FeAsO4⋅2H2O and jarosites at the top and bottom of the columns could adsorb to and coprecipitate with As(III) and As(V), resulting in the transfer of As from solution to solid phases, thus further affecting As speciation transformation. The distribution difference of Fe/S energy substrates could apparently affect Fe/S/As speciation transformation and bacterial depth distribution between the top and bottom of the water columns. These findings are valuable for elucidating As fate and toxicity mediated by microbially driven Fe/S redox in AMD environments.

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Section: Discussionmentioning

confidence: 99%

Correlation Between Fe/S/As Speciation Transformation and Depth Distribution of Acidithiobacillus ferrooxidans and Acidiphilium acidophilum in Simulated Acidic Water Column

et al. 2022

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“…According to the different doses of peat added, we observed that the adsorption processes on colloidal fractions of the soils played a key role in the As solubility. Although the cation exchange capacity (CEC) and the organic carbon (OC) content of the analyzed soil samples was low, peat additions increased the soil OC content, as well as the total humic extract and humic and fulvic acids, which provides an important content of reactive colloidal fractions that allow the complexation of the different chemical forms of As (mainly arsenates) [58]. The additions of 2% and 5% of peat enhance arsenic retention above 98% in most cases (except in AZN), thus reducing its solubility.…”

Section: Discussionmentioning

confidence: 99%

Arsenic Fixation in Polluted Soils by Peat Applications

et al. 2020

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Soil arsenic (As) pollution is still a major concern due to its high toxicity and carcinogenicity, thus, the study of decontamination techniques, as the organic amendment applications, keeps upgrading. This research evaluates the potential remediation of peat in different As-polluted soils, by assessing the decrease of As solubility and its toxicity through bioassays. Obtained reduction in As solubility by peat addition was strongly related to the increase of humic substances, providing colloids that allow the complexation of As compounds. Calcareous soils have been the least effective at buffering As pollution, with higher As concentrations and worse biological response (lower soil respiration and inhibition of lettuce germination). Non-calcareous soils showed lower As concentrations due to the higher iron content, which promotes As fixation. Although in both cases, peat addition improves the biological response, it also showed negative effects, hypothetically due to peat containing toxic polyphenolic compounds, which in the presence of carbonates appears to be concealed. Both peat dose tested (2% and 5%) decreased drastically As mobility; however, for calcareous soils, as there is no phytotoxic effect, the 5% dose is the most recommended; while for non-calcareous soils the efficient peat dose for As decontamination could be lower.

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“…thermosulfidooxidans YN-22 (accession number of 16S rRNA gene in GenBank: DQ650351) was obtained from the Key Laboratory of Biometallurgy of Ministry of Education of China (Changsha, China). The strain was originally isolated from an acidic Feand S-rich hot spring and shows high Fe(II) oxidation activity [18,38]. The morphology of the bacterial cells characterized by SEM is shown in Fig.…”

Section: Bacterial Strain Of Sb Thermosulfidooxidans and Cultivation ...mentioning

confidence: 99%

“…The above results also further confirmed that schwertmannite and Fe(OH)3 play a crucial role in improving the As(V) removal ability of the bio-synthesized Fe(III)/Al (hydr)oxides composite@cells-based adsorbent. Although jarosites also have a chemical structure that allows a substitution of a variety of metals, the As adsorption capability is significantly reduced due to a lack of binding sites [18].…”

Section: Arsenic Speciation In Precipitatesmentioning

confidence: 99%

“…One of the primary sources of As pollution in acidic conditions is the oxidative dissolution of arsenopyrite (FeAsS), which can be greatly promoted by AIOP. The released As can be immobilized via the formation of As-bearing Fe(III) precipitates (e.g., amorphous ferric arsenate (FeAsO4) and wellcrystallized scorodite (FeAsO4•2H2O)) or via adsorption onto the secondary products such as schwertmannite ([Fe8O8(OH)8-2x(SO4)x, where 1 ≤ x ≤ 1.75) and jarosites (Fe(III) (hydr)oxides) commonly formed during arsenopyrite bio-oxidation [18]. The bio-oxidation of Fe(II) by acidophilic prokaryotes is a necessary precondition for the formation of secondary Fe(III) (hydr)oxides.…”

Section: Introductionmentioning

confidence: 99%

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