Enhancing long-term As immobilization by NO₃-MgFe LDH coupling with Acidovorax sp. BoFeN1

Abstract

Arsenic (As) contamination of groundwater is a serious global issue requiring effective and sustainable remediation strategies. For long-term As immobilization, this study explores the potential of in-situ magnetite precipitation, induced by anaerobic nitrate-reducing Fe(II) -oxidizing (NRFO) bacteria. A nitrate-intercalated layered double hydroxide (NO₃-MgFe LDH) was introduced to provide nitrate as an electron acceptor for Fe(II) bio-oxidation and serve as an iron-based precursor in magnetite formation. The experimental results showed that NO₃-MgFe LDH was transformed into green rust (GR) in the presence of Fe(II) and HCO₃⁻. Meanwhile, 0.5 g/L of NO₃-MgFe LDH released cumulatively about 1.21 mM of nitrate within 12 h, promoting the transformation of GR into magnetite induced by Acidovorax sp. BoFeN1. As a result, the aqueous As concentration decreased from 2 mg/L to <0.008 mg/L, with approximately 70% of As confined in recalcitrant Fe oxides, suggesting high potential for long-term As immobilization. Environmental factors influenced the transformation process: a lower Fe(II) concentration (0.5 mM) delayed GR formation, while varying HCO₃⁻ concentrations (2.5–10 mM) had minimal effect. Subsequently, an elevated As level (5 mg/L) inhibited the bio-formation of magnetite, leading to lepidocrocite as the dominant mineral phase. Given the stability of magnetite, this study provides a cost-effective and environmentally friendly strategy for the durable in-situ remediation of As-contaminated groundwater.

h

References

[1] ZhangD, GuoH-m, XiuW, et al.. In-situ mobilization and transformation of iron oxides-adsorbed arsenate in natural groundwater [J]. Journal of Hazardous Materials, 2017, 321: 228-237

[2] GuoH-m, LiuC, LuH, et al.. Pathways of coupled arsenic and iron cycling in high arsenic groundwater of the Hetao basin, Inner Mongolia, China: An iron isotope approach [J]. Geochimica et Cosmochimica Acta, 2013, 112: 130-145

[3] NaujokasM F, AndersonB, AhsanH, et al.. The broad scope of health effects from chronic arsenic exposure: Update on a worldwide public health problem [J]. Environmental Health Perspectives, 2013, 121(3): 295-302

[4] ParkJ, AnJ, ChungH, et al.. Reduction of bioaccessibility of As in soil through in situ formation of amorphous Fe oxides and its long-term stability [J]. Science of the Total Environment, 2020, 745: 140989

[5] GanesanS, DangritS, JanjaroenD. Long-term arsenate removal by an iron-amended biosand filter: Modes of operation according to groundwater composition [J]. Journal of Environmental Chemical Engineering, 2023, 11(3): 109814

[6] XieX-j, PengK, WangY-x, et al.. In situ arsenic immobilization by chemical oxidation: Field trial and reactive transport modelling [J]. Journal of Hydrology, 2020, 583: 124645

[7] XieX-j, PiK-f, LiuY-q, et al.. In-situ arsenic remediation by aquifer iron coating: Field trial in the Datong basin, China [J]. Journal of Hazardous Materials, 2016, 302: 19-26

[8] PedersenH D, PostmaD, JakobsenR. Release of arsenic associated with the reduction and transformation of iron oxides [J]. Geochimica et Cosmochimica Acta, 2006, 70(16): 4116-4129

[9] Van GenuchtenC M, BehrendsT, DideriksenK. Emerging investigator series: Interdependency of green rust transformation and the partitioning and binding mode of arsenic [J]. Environmental Science Processes & Impacts, 2019, 21(9): 1459-1476

[10] SunJ, ChillrudS N, MaillouxB J, et al.. Enhanced and stabilized arsenic retention in microcosms through the microbial oxidation of ferrous iron by nitrate [J]. Chemosphere, 2016, 144: 1106-1115

[11] GorskiC A, SchererM M. Influence of magnetite stoichiometry on Fe^II uptake and nitrobenzene reduction [J]. Environmental Science & Technology, 2009, 43(10): 3675-3680

[12] XiuW, GuoH-m, LiuQ, et al.. Arsenic removal and transformation by pseudomonas sp. strain GE-1-induced ferrihydrite: Co-precipitation versus adsorption [J]. Water, Air, & Soil Pollution, 2015, 226(6): 167

[13] XiuW, GuoH-m, ShenJ-x, et al.. Stimulation of Fe(II) oxidation, biogenic lepidocrocite formation, and arsenic immobilization by pseudogulbenkiania sp. strain 2002 [J]. Environmental Science & Technology, 2016, 50(12): 6449-6458

[14] HohmannC, MorinG, Ona-NguemaG, et al.. Molecular-level modes of As binding to Fe(III) (oxyhydr) oxides precipitated by the anaerobic nitrate-reducing Fe(II)-oxidizing Acidovorax sp. strain BoFeN1 [J]. Geochimica et Cosmochimica Acta, 2011, 75(17): 4699-4712

[15] WangZ, GuoH-m, XiuW, et al.. High arsenic groundwater in the Guide basin, northwestern China: Distribution and genesis mechanisms [J]. Science of the Total Environment, 2018, 640: 194-206

[16] LiuC W, WuM-z. Geochemical, mineralogical and statistical characteristics of arsenic in groundwater of the Lanyang Plain, Taiwan [J]. Journal of Hydrology, 2019, 577: 123975

[17] PengC, SundmanA, BryceC, et al.. Oxidation of Fe(II) - organic matter complexes in the presence of the mixotrophic nitrate-reducing Fe(II) -oxidizing bacterium Acidovorax sp. BoFeN1 [J]. Environmental Science & Technology, 2018, 52(10): 5753-5763

[18] XiuW, YuX-n, GuoH-m, et al.. Facilitated arsenic immobilization by biogenic ferrihydrite-goethite biphasic Fe(III) minerals (Fh-Gt bio-bi-minerals) [J]. Chemosphere, 2019, 225: 755-764

[19] LiuQ-w, FangY, GeH-y, et al.. Promoting the transformation of green rust for As immobilization with Acidovorax sp. strain BoFeN1 [J]. Chemosphere, 2024, 362: 142764

[20] MiotJ, LiJ-h, BenzeraraK, et al.. Formation of single domain magnetite by green rust oxidation promoted by microbial anaerobic nitrate-dependent iron oxidation [J]. Geochimica et Cosmochimica Acta, 2014, 139: 327-343

[21] MandalS, MayadeviS, KulkarniB D. Adsorption of aqueous selenite [Se(IV)] species on synthetic layered double hydroxide materials [J]. Industrial & Engineering Chemistry Research, 2009, 48(17): 7893-7898

[22] LinY-j, FangQ-l, ChenB-l. Perchlorate uptake and molecular mechanisms by magnesium/aluminum carbonate layered double hydroxides and the calcined layered double hydroxides [J]. Chemical Engineering Journal, 2014, 237: 38-46

[23] ZhangZ-d, QinJ-y, ZhangW-c, et al.. Synthesis of a novel dual layered double hydroxide hybrid nanomaterial and its application in epoxy nanocomposites [J]. Chemical Engineering Journal, 2020, 381: 122777

[24] OlfsH W, Torres-DoranteL O, EckeltR, et al.. Comparison of different synthesis routes for Mg–Al layered double hydroxides (LDH): Characterization of the structural phases and anion exchange properties [J]. Applied Clay Science, 2009, 43(3–4): 459-464

[25] SilvaV, KamogawaM Y, MarangoniR, MangrichA S, WypychF. Layered double hydroxides as matrizes for nitrate slow release fertilizers [J]. Revista Brasileira de Ciencia Solo, 2014, 38: 272-277

[26] FangY, XieH-h, YangY, et al.. Bicarbonate-mediated enhanced successive oxidation and adsorption of As (III) in heterogeneous PMS activation process: Mechanism and practicability [J]. Journal of Environmental Chemical Engineering, 2023, 11(2): 109289

[27] MiotJ, BenzeraraK, MorinG, et al.. Transformation of vivianite by anaerobic nitrate-reducing iron-oxidizing bacteria [J]. Geobiology, 2009, 7(3): 373-384

[28] WeberK A, HedrickD B, PeacockA D, et al.. Physiological and taxonomic description of the novel autotrophic, metal oxidizing bacterium, Pseudogulbenkiania sp. strain 2002 [J]. Applied Microbiology and Biotechnology, 2009, 83(3): 555-565

[29] KluegleinN, KapplerA. Abiotic oxidation of Fe(II) by reactive nitrogen species in cultures of the nitrate-reducing Fe(II) oxidizer Acidovorax sp. BoFeN1–questioning the existence of enzymatic Fe(II) oxidation [J]. Geobiology, 2013, 11(2): 180-190

[30] GilcreasF W. Standard methods for the examination of water and waste water [J]. American Journal of Public Health and the Nation’s Health, 1966, 56(3): 387-388

[31] ZubairY O, FuchidaS, OyamaK, et al.. Morphologically controlled synthesis of MgFe-LDH using MgO and succinic acid for enhanced arsenic adsorption: Kinetics, equilibrium, and mechanism studies [J]. Journal of Environmental Sciences, 2025, 148: 637-649

[32] WangQ-w, YanX-l, MaM-j, et al.. Application and mechanism of Fenton-like iron-based functional materials for arsenite removal [J]. Transactions of Nonferrous Metals Society of China, 2022, 32(12): 4139-4155

[33] DaenzerR, FeldmannT, DemopoulosG P. Oxidation of ferrous sulfate hydrolyzed slurry: Kinetic aspects and impact on As(V) removal [J]. Industrial & Engineering Chemistry Research, 2015, 54(6): 1738-1747

[34] Ureña-AmateM D, BoutarbouchN D, Del Mar Socias-VicianaM, et al.. Controlled release of nitrate from hydrotalcite modified formulations [J]. Applied Clay Science, 2011, 52(4): 368-373

[35] BerberM R, HafezI H, MinagawaK, et al.. A sustained controlled release formulation of soil nitrogen based on nitrate-layered double hydroxide nanoparticle material [J]. Journal of Soils and Sediments, 2014, 14(1): 60-66

[36] KotlarA M, Wallace Pereira De CarvalhoH, IversenB V, et al.. Nitrate leaching from layered double hydroxides in tropical and temperate soils [J]. Applied Clay Science, 2020, 184: 105365

[37] BerberM R, HafezI H. Synthesis of a new nitrate-fertilizer form with a controlled release behavior via an incorporation technique into a clay material [J]. Bulletin of Environmental Contamination and Toxicology, 2018, 101(6): 751-757

[38] TranH N, LinC C, WooS H, et al.. Efficient removal of copper and lead by Mg/Al layered double hydroxides intercalated with organic acid anions: Adsorption kinetics, isotherms, and thermodynamics [J]. Applied Clay Science, 2018, 154: 17-27

[39] HudcováB, FeinJ B, TsangD C W, et al.. Mg-Fe LDH-coated biochars for metal(loid) removal: Surface complexation modeling and structural change investigations [J]. Chemical Engineering Journal, 2022, 432: 134360

[40] LiuT-x, ChenD-d, LuoX-b, et al.. Microbially mediated nitrate-reducing Fe(II) oxidation: Quantification of chemodenitrification and biological reactions [J]. Geochimica et Cosmochimica Acta, 2019, 256: 97-115

[41] LiuQ W, FangY, GeH Y, YangY, LiH P. Promoting the transformation of green rust for As immobilization with Acidovorax sp. strain BoFeN1 [J]. Chemosphere, 2024, 362: 142764

RIGHTS & PERMISSIONS

Central South University