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Ahmad A, van Genuchten CM. Deep-dive into iron-based co-precipitation of arsenic: A review of mechanisms derived from synchrotron techniques and implications for groundwater treatment. WATER RESEARCH 2024; 249:120970. [PMID: 38064786 DOI: 10.1016/j.watres.2023.120970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 09/25/2023] [Accepted: 12/02/2023] [Indexed: 01/03/2024]
Abstract
The co-precipitation of Fe(III) (oxyhydr)oxides with arsenic (As) is one of the most widespread approaches to treat As-contaminated groundwater in both low- and high-income settings. Fe-based co-precipitation of As occurs in a variety of conventional and decentralized treatment schemes, including aeration and sand filtration, ferric chloride addition and technologies based on controlled corrosion of Fe(0) (i.e., electrocoagulation). Despite its ease of deployment, Fe-based co-precipitation of As entails a complex series of chemical reactions that often occur simultaneously, including electron-transfer reactions, mineral nucleation, crystal growth, and As sorption. In recent years, the growing use of sophisticated synchrotron-based characterization techniques in water treatment research has generated new detailed and mechanistic insights into the reactions that govern As removal efficiency. The purpose of this critical review is to synthesize the current understanding of the molecular-scale reaction pathways of As co-precipitation with Fe(III), where the source of Fe(III) can be ferric chloride solutions or oxidized Fe(II) sourced from natural Fe(II) in groundwater, ferrous salts or controlled Fe(0) corrosion. We draw primarily on the mechanistic knowledge gained from spectroscopic and nano-scale investigations. We begin by describing the least complex reactions relevant in these conditions (Fe(II) oxidation, Fe(III) polymerization, As sorption in single-solute systems) and build to multi-solute systems containing common groundwater ions that can alter the pathways of As uptake during Fe(III) co-precipitation (Ca, Mg bivalent cations; P, Si oxyanions). We conclude the review by providing a perspective on critical knowledge gaps remaining in this field and new research directions that can further improve the understanding of As removal via Fe(III) co-precipitation.
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Affiliation(s)
- A Ahmad
- Department of Sustainable Development, Environmental Science and Engineering, KTH Royal Institute of Technology, Stockholm, Sweden; SIBELCO, Ankerpoort NV, Op de Bos 300, 6223 EP, Maastricht, the Netherlands
| | - C M van Genuchten
- Department of Geochemistry, Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, Copenhagen, Denmark.
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Barron A, Sun J, Passaretti S, Sbarbati C, Barbieri M, Colombani N, Jamieson J, Bostick BC, Zheng Y, Mastrocicco M, Petitta M, Prommer H. In situ arsenic immobilisation for coastal aquifers using stimulated iron cycling: Lab-based viability assessment. APPLIED GEOCHEMISTRY : JOURNAL OF THE INTERNATIONAL ASSOCIATION OF GEOCHEMISTRY AND COSMOCHEMISTRY 2022; 136:105155. [PMID: 34955596 PMCID: PMC8699153 DOI: 10.1016/j.apgeochem.2021.105155] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Arsenic (As) is one of the most harmful and widespread groundwater contaminants globally. Besides the occurrence of geogenic As pollution, there is also a large number of sites that have been polluted by anthropogenic activities, with many of those requiring active remediation to reduce their environmental impact. Cost-effective remedial strategies are however still sorely needed. At the laboratory-scale in situ formation of magnetite through the joint addition of nitrate and Fe(II) has shown to be a promising new technique. However, its applicability under a wider range of environmental conditions still needs to be assessed. Here we use sediment and groundwater from a severely polluted coastal aquifer and explore the efficiency of nitrate-Fe(II) treatments in mitigating dissolved As concentrations. In selected experiments >99% of dissolved As was removed, compared to unamended controls, and maintained upon addition of lactate, a labile organic carbon source. Pre- and post experimental characterisation of iron (Fe) mineral phases suggested a >90% loss of amorphous Fe oxides in favour of increased crystalline, recalcitrant oxide and sulfide phases. Magnetite formation did not occur via the nitrate-dependent oxidation of the amended Fe(II) as originally expected. Instead, magnetite is thought to have formed by the Fe(II)-catalysed transformation of pre-existing amorphous and crystalline Fe oxides. The extent of amorphous and crystalline Fe oxide transformation was then limited by the exhaustion of dissolved Fe(II). Elevated phosphate concentrations lowered the treatment efficacy indicating joint removal of phosphate is necessary for maximum impact. The remedial efficiency was not impacted by varying salinities, thus rendering the tested approach a viable remediation method for coastal aquifers.
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Affiliation(s)
- Alyssa Barron
- School of Earth Sciences, University of Western Australia, Crawley, WA, Australia
- CSIRO Land and Water, Wembley Australia
| | - Jing Sun
- School of Earth Sciences, University of Western Australia, Crawley, WA, Australia
- CSIRO Land and Water, Wembley Australia
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China
| | | | - Chiara Sbarbati
- Dept. of Earth Sciences, “Sapienza” University of Roma, Roma, Italy
| | | | | | - James Jamieson
- School of Earth Sciences, University of Western Australia, Crawley, WA, Australia
- CSIRO Land and Water, Wembley Australia
| | | | - Yan Zheng
- School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen (China)
| | | | - Marco Petitta
- Dept. of Earth Sciences, “Sapienza” University of Roma, Roma, Italy
| | - Henning Prommer
- School of Earth Sciences, University of Western Australia, Crawley, WA, Australia
- CSIRO Land and Water, Wembley Australia
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3
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Polyphosphates as an effective vehicle for delivery of bioavailable nanoparticulate iron(III). Food Chem 2021; 373:131477. [PMID: 34731816 DOI: 10.1016/j.foodchem.2021.131477] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Revised: 09/22/2021] [Accepted: 10/23/2021] [Indexed: 12/16/2022]
Abstract
Polyphosphates are widely used food additives with the potential to increase iron bioavailability but chemical nature of their soluble complexes with iron remains largely unknown. Here, pyrophosphate, tripolyphosphate, hexametaphosphate and ∼25-chain-length polyphosphate solubilized 896, 896, 1120 and 1344 mg Fe(III) per g, respectively, at neutral pH by mediating the formation of highly-negatively-charged ferric hydroxide-polyphosphate nanoparticles (PolyP-FeONPs). PolyP-FeONPs displayed fading yellow color with increasing initial dissolved P/Fe ratio ((P/Fe)init) and decreasing polyphosphate length due to rising proportion of Fe(III)-phosphate bonds, and specifically, pyrophosphate resulted colorless PolyP-FeONPs at (P/Fe)init ≥ 4. PolyP-FeONPs had weak pro-oxidant activity in glyceryl trilinoleate emulsion and good colloidal stability under spray/freeze-drying and gastrointestinal conditions. Serum iron kinetics in rats revealed sustained iron release and ∼170% iron bioavailability of oral PolyP-FeONPs relative to FeSO4. Calcein-fluorescence-quenching assay in polarized Caco-2 cells unveiled divalent-metal-transporter-1-independent and macropinocytosis-dependent iron uptake from PolyP-FeONPs. This study helps develop food-compatible, highly-bioavailable and sustained-release iron preparations.
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Malakar A, Kanel SR, Ray C, Snow DD, Nadagouda MN. Nanomaterials in the environment, human exposure pathway, and health effects: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 759:143470. [PMID: 33248790 DOI: 10.1016/j.scitotenv.2020.143470] [Citation(s) in RCA: 79] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 10/24/2020] [Accepted: 10/24/2020] [Indexed: 05/04/2023]
Abstract
Nanomaterials (NMs), both natural and synthetic, are produced, transformed, and exported into our environment daily. Natural NMs annual flux to the environment is around 97% of the total and is significantly higher than synthetic NMs. However, synthetic NMs are considered to have a detrimental effect on the environment. The extensive usage of synthetic NMs in different fields, including chemical, engineering, electronics, and medicine, makes them susceptible to be discharged into the atmosphere, various water sources, soil, and landfill waste. As ever-larger quantities of NMs end up in our environment and start interacting with the biota, it is crucial to understand their behavior under various environmental conditions, their exposure pathway, and their health effects on human beings. This review paper comprises a large portion of the latest research on NMs and the environment. The article describes the natural and synthetic NMs, covering both incidental and engineered NMs and their behavior in the natural environment. The review includes a brief discussion on sampling strategies and various analytical tools to study NMs in complex environmental matrices. The interaction of NMs in natural environments and their pathway to human exposure has been summarized. The potential of NMs to impact human health has been elaborated. The nanotoxicological effect of NMs based on their inherent properties concerning to human health is also reviewed. The knowledge gaps and future research needs on NMs are reported. The findings in this paper will be a resource for researchers working on NMs all over the world to understand better the challenges associated with NMs in the natural environment and their human health effects.
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Affiliation(s)
- Arindam Malakar
- Nebraska Water Center, part of the Robert B. Daugherty Water for Food Global Institute 2021 Transformation Drive, University of Nebraska, Lincoln, NE 68588-0844, USA
| | - Sushil R Kanel
- Nebraska Water Center, part of the Robert B. Daugherty Water for Food Global Institute 2021 Transformation Drive, University of Nebraska, Lincoln, NE 68588-0844, USA; Department of Chemistry, Wright State University, Dayton, OH 45435, USA.
| | - Chittaranjan Ray
- Nebraska Water Center, part of the Robert B. Daugherty Water for Food Global Institute 2021 Transformation Drive, University of Nebraska, Lincoln, NE 68588-0844, USA
| | - Daniel D Snow
- School of Natural Resources and Nebraska Water Center, part of the Robert B. Daugherty Water for Food Global Institute, 202 Water Sciences Laboratory, University of Nebraska, Lincoln, NE 68583-0844, USA
| | - Mallikarjuna N Nadagouda
- Department of Mechanical and Materials Engineering, Wright State University, 3640 Colonel Glenn Hwy., Dayton, OH 45435, USA
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van Genuchten CM, Ahmad A. Groundwater As Removal by As(III), Fe(II), and Mn(II) Co-Oxidation: Contrasting As Removal Pathways with O 2, NaOCl, and KMnO 4. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:15454-15464. [PMID: 33174730 DOI: 10.1021/acs.est.0c05424] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Effective arsenic (As) removal from groundwater is a pressing need in view of increasingly stringent As drinking water limits in some US states and European countries. In this study, we compared the addition of weak (O2), intermediate (NaOCl), and strong (KMnO4) groundwater oxidants on the fate of As during As(III), Fe(II), and Mn(II) co-oxidation. Experiments were performed with 50 μg/L As(III), 5 mg/L Fe(II), and 0.5 mg/L Mn(II) in solutions containing relevant groundwater ions, with the reaction products characterized by As K-edge X-ray absorption spectroscopy (XAS). Adding O2 by aeration was the least effective method, unable to decrease As to below 10 μg/L, which was attributed to inefficient As(III) oxidation. Dosing NaOCl (55 μM) consistently removed As to <10 μg/L (and often <5 μg/L). The As K-edge XAS data of the NaOCl samples indicated complete As(III) oxidation and As(V) sorption to coprecipitated hydrous ferric oxide (HFO) in the binuclear, bridging (2C) complex. The most effective As removal was observed with KMnO4 (40 μM), which completely oxidized As(III) and yielded residual As concentrations that were less than (by as much as 50%) or equal to the NaOCl experiments. Furthermore, the average As-metal bond length of the KMnO4 solids (RAs-Fe/Mn = 3.24 ± 0.02 Å) was systematically shorter than the NaOCl solids (RAs-Fe/Mn = 3.29 ± 0.02 Å), consistent with As(V) sorption to both MnO2 and HFO. These findings can be used to optimize groundwater As treatment to meet relevant drinking water guidelines, while considering the As uptake mode and characteristics of the particle suspension (i.e., colloidal stability and filterability).
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Affiliation(s)
- Case M van Genuchten
- Department of Geochemistry, Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, 1350 Copenhagen, Denmark
| | - Arslan Ahmad
- SIBELCO Ankerpoort NV, Op de Bos 300, 6223 EP Maastricht, The Netherlands
- KWR Water Cycle Research Institute, Groningenhaven 7, 3433 PE Nieuwegein, The Netherlands
- Department of Environmental Technology, Wageningen University and Research (WUR), Droevendaalsesteeg 4, 6708 PB Wageningen, The Netherlands
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Park J, Chung H, Kim SH, An J, Nam K. Effect of neutralizing agents on the type of As co-precipitates formed by in situ Fe oxides synthesis and its impact on the bioaccessibility of As in soil. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 743:140686. [PMID: 32673914 DOI: 10.1016/j.scitotenv.2020.140686] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 06/30/2020] [Accepted: 06/30/2020] [Indexed: 06/11/2023]
Abstract
The bioaccessibility of heavy metals in soil is closely related to their potential risk. Therefore, developing techniques for reducing it needs considerable attention. In this study, we aimed to co-precipitate soil As(V) through an in situ formation of Fe oxides, thereby reducing its bioaccessibility. Soil As(V) was co-precipitated by introducing 2% Fe-nitrate (w/w) and 30% water (v/w) into soil at pH ~7. Two different neutralizing agents (NaOH and CaO) were used to induce the precipitation of Fe oxides, and their effects on the speciation of As were investigated. In all the stabilized soils, the exchangeable As fraction decreased, and the fraction of As bound to amorphous Fe oxides increased by a factor of more than 1.4. In contrast, a marked decrease in bioaccessibility of As was achieved using NaOH (40% to 7%). X-ray absorption spectroscopy analysis demonstrated that highly bioaccessible forms of calcium iron arsenate (yukonite and arseniosiderite) could be generated in CaO-stabilized soil. Our study found that neutralizing agents may play an important role in stabilizing As(V) and lowering its bioaccessibility through determining the type of formed Fe oxides in soil.
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Affiliation(s)
- Jinhee Park
- Department of Civil & Environmental Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Hyeonyong Chung
- Department of Civil & Environmental Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Sang Hyun Kim
- Department of Civil & Environmental Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Jinsung An
- Department of Biological & Environmental Engineering, Semyung University, 65 Semyung-ro, Jecheon-si, Chungcheongbuk-do 27136, Republic of Korea.
| | - Kyoungphile Nam
- Department of Civil & Environmental Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
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Herath I, Zhao FJ, Bundschuh J, Wang P, Wang J, Ok YS, Palansooriya KN, Vithanage M. Microbe mediated immobilization of arsenic in the rice rhizosphere after incorporation of silica impregnated biochar composites. JOURNAL OF HAZARDOUS MATERIALS 2020; 398:123096. [PMID: 32768840 DOI: 10.1016/j.jhazmat.2020.123096] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 05/14/2020] [Accepted: 05/27/2020] [Indexed: 06/11/2023]
Abstract
This study mechanistically addressed for the first time, the contradiction between the application of many biochars to paddy soil and increased arsenic (As) release as employed by most of previous studies. Three types of biochar containing natural and chemical forms of Si: (i) unmodified rice husk biochar (RHBC), (ii) RHBC modified with Si fertilizer (Si-RHBC), and (iii) RHBC modified with nanoparticles of montmorillonite clay (NM-RHBC) were applied in As-contaminated paddy soil to examine their potential to control the mobility of As in the soil-microbe-rice system. Both Si-RHBC and NM-RHBC decreased As concentration in porewater by 40-65 %, while RHBC decreased by 30-44 % compared to biochar unamended soil from tillering to maturing stage. At tillering stage, RHBC, Si-RHBC and NM-RHBC amendments significantly decreased As(III) concentration in the rice rhizosphere by 57, 76 and 73 %, respectively compared to the control soil. The immobilization of As is due to: (i) lowering of microbe mediated As release from iron minerals, (ii) oxidation of As(III) to As(V) by aioA gene, and (iii) adsorption on a Si-ferrihydrite complex. The decrease of more toxic As(III) and its oxidation to less mobile As(V) by Si-rich biochar amendments is a promising As detoxification phenomenon in the rice rhizosphere.
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Affiliation(s)
- Indika Herath
- School of Civil Engineering and Surveying, Faculty of Health, Engineering and Sciences, University of Southern Queensland, West Street, Toowoomba, Queensland 4350, Australia
| | - Fang-Jie Zhao
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Jochen Bundschuh
- School of Civil Engineering and Surveying, Faculty of Health, Engineering and Sciences, University of Southern Queensland, West Street, Toowoomba, Queensland 4350, Australia; UNESCO Chair on Groundwater Arsenic within the 2030 Agenda for Sustainable Development, University of Southern Queensland, West Street, Toowoomba 4350, Queensland, Australia.
| | - Peng Wang
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Jing Wang
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Yong Sik Ok
- Korea Biochar Research Center, O-Jeong Eco-Resilience Institute (OJERI) & Division of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, South Korea
| | - Kumuduni Niroshika Palansooriya
- Korea Biochar Research Center, O-Jeong Eco-Resilience Institute (OJERI) & Division of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, South Korea
| | - Meththika Vithanage
- Office of the Dean, Faculty of Applied Sciences, Jayewardenepura, Nugegoda, Sri Lanka
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Jun YS, Zhu M, Peak D. Frontiers and advances in environmental soil chemistry: a special issue in honor of Prof. Donald L. Sparks. GEOCHEMICAL TRANSACTIONS 2020; 21:6. [PMID: 32303855 PMCID: PMC7164233 DOI: 10.1186/s12932-020-00070-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Affiliation(s)
- Young-Shin Jun
- Department of Energy, Environmental & Chemical Engineering, Washington University, St. Louis, MO 63130 USA
| | - Mengqiang Zhu
- Department of Ecosystem Science and Management, University of Wyoming, Laramie, WY 82071 USA
| | - Derek Peak
- Department of Soil Science, University of Saskatchewan, Saskatoon, SK S7N 5A8 Canada
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