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Shi M, Min X, Zhang W, Li K, Wu J, Ai Z, Ke Y, Wang Q, Yan X. (Na, Pb)-Jarosite nucleation and growth on anglesite: Implications for inhibition of Pb releasing. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 901:165972. [PMID: 37532039 DOI: 10.1016/j.scitotenv.2023.165972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 07/21/2023] [Accepted: 07/30/2023] [Indexed: 08/04/2023]
Abstract
The mobility and bioavailability of Pb can be significantly reduced by Pb-bearing minerals encapsulation in jarosite-group minerals, especially in sulfate-rich environments. However, the kinetic pathways and mechanisms of jarosite-group minerals formations on Pb-bearing mineral surfaces are not well understood. Here, time-resolved heterogeneous (Na, Pb)-jarosite nucleation and growth on anglesite were explored to gain insights into the encapsulation mechanisms. The initial dissolution of anglesite were clearly distinguished, and for the first time, the facet-specific heterogeneous nucleation of (Na, Pb)-jarosite on anglesite was demonstrated. Density functional theory calculations revealed higher adsorption energies and electronic interactions of FeSO4+ complex on anglesite (020), (140), (110) facets, attributed to the preferential nucleation of (Na, Pb)-jarosite on these facets, which resulted in effective passivation of the facets resistant to dissolution. An interpretation was proposed where (Na, Pb)-jarosite grew via a particle-attachment pathway involving the formation of amorphous intermediate, and subsequently, it transformed to the crystalline phase by solid-state conversion. These observations might improve the mechanistic understanding of interface interactions between slightly soluble Pb-bearing minerals and iron minerals, with implications for Pb immobilization in sulfate-rich environments.
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Affiliation(s)
- Meiqing Shi
- School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, China
| | - Xiaobo Min
- School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha, Hunan 410083, China
| | - Wenchao Zhang
- School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha, Hunan 410083, China
| | - Kaizhong Li
- School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha, Hunan 410083, China
| | - Jiahui Wu
- School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha, Hunan 410083, China
| | - Zhongbin Ai
- Science Environmental Protection Co. Ltd., Changsha 410000, China
| | - Yong Ke
- School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha, Hunan 410083, China
| | - Qingwei Wang
- School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha, Hunan 410083, China.
| | - Xu Yan
- School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha, Hunan 410083, China.
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Cao X, Zhang Q, Yang W, Fang L, Liu S, Ma R, Guo K, Ma N. Lead-chlorine synergistic immobilization mechanism in municipal solid waste incineration fly ash (MSWIFA)-based magnesium potassium phosphate cement. JOURNAL OF HAZARDOUS MATERIALS 2023; 442:130038. [PMID: 36166907 DOI: 10.1016/j.jhazmat.2022.130038] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 09/05/2022] [Accepted: 09/18/2022] [Indexed: 06/16/2023]
Abstract
The high chlorine (Cl) and lead (Pb) content characteristics of municipal solid waste incineration fly ash (MSWIFA) pose environmental risks and hinder resource utilization. Herein, an MSWIFA-based magnesium potassium phosphate cement (MKPC) preparation strategy was developed, which allowed the MSWIFA recycling and the Pb-Cl synergistic immobilization without the washing pretreatment. The compressive strength of the resulting 10 wt% MSWIFA-based MKPC was 28.44 MPa, with over 99.2% reduction in leaching toxicity of Pb and Cl. The high-angle annular dark field scanning transmission electron microscope (HAADF-STEM) and X-ray absorption spectroscopy (XAS) analyzes showed that Pb, phosphate and Cl- formed Pb5(PO4)3Cl in MKPC. In-situ X-ray diffraction (XRD) tests showed that Pb3(PO4)2 was gradually transformed to Pb5(PO4)3Cl through a dissolution-precipitation process. The formation energy, Bader charge, charge density difference and density of states (DOS) of Pb5(PO4)3Cl were analyzed by first-principles calculations, confirming that Pb5(PO4)3Cl was more thermodynamically stable than Pb3(PO4)2 and PbCl2 and that electronic interactions between Pb-p, O-p, P-p and Cl-p orbits were the origin of Pb-Cl synergistic immobilization. This work provides a new strategy for the resource utilization of MSWIFA without washing pretreatment, and provides an in-depth understanding of the Pb-Cl synergistic immobilization mechanism.
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Affiliation(s)
- Xing Cao
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Qiushi Zhang
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Weichen Yang
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Lin Fang
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Shiwei Liu
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Rui Ma
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China.
| | - Kai Guo
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Ning Ma
- China Electronic System Engineering Co.,Ltd, Beijing 100040, China
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3
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Gao Y, Trueman BF, Gagnon GA. Early phase effects of silicate and orthophosphate on lead (Pb) corrosion scale development and Pb release. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 321:115947. [PMID: 35977436 DOI: 10.1016/j.jenvman.2022.115947] [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: 04/30/2022] [Revised: 07/30/2022] [Accepted: 08/02/2022] [Indexed: 06/15/2023]
Abstract
Orthophosphate is widely used to control lead (Pb) release in drinking water distribution systems, but phosphorus addition is not sustainable. Alternative corrosion control treatments are needed, and sodium silicate is one possibility. Here, pre-corroded Pb coupons-with and without free chlorine-were used to examine early-phase corrosion scale development after silicate addition, with orthophosphate as a reference corrosion inhibitor. Scale development was evaluated in terms of total Pb release, phase transformation, electrochemical impedance, morphological changes, Pb dissolution kinetics, and short-term Pb-Cu galvanic corrosion. Elevated Pb release occurred for approximately one month after silicate addition, and total Pb release peaked at 1968.1 μg/L and 1176.9 μg/L from systems with and without free chlorine, respectively. In contrast, orthophosphate-treated coupons exhibited fewer, less pronounced spikes in Pb release. By day 354, the median total Pb release from orthophosphate-treated coupons with and without free chlorine had decreased to 3.7 and 5.0 μg/L, respectively, while the median total Pb release from corresponding silicate-treated coupons was much higher, at 44.9 μg/L and 34.3 μg/L. Calcium lead apatite (Ca0.56Pb3.77(PO4)3OH0.67) was identified in orthophosphate-treated scales, with hydroxylpyromorphite (Pb5(PO4)3OH) present in the absence of free chlorine. Plattnerite occurred on coupons in all chlorinated systems. Pb silicate compounds were not detected, but Ca2SiO4 and Na2Ca2(SiO3)3 were identified by X-ray powder diffraction. The charge transfer: film resistance ratio characterizing the orthophosphate-treated coupons decreased slowly while that of the silicate-treated coupons increased after silicate was added. These variations suggest orthophosphate provided better corrosion control than silicate did. Silicate treatment generally caused degradation of the top Pb scale layer, resulting in elevated Pb release, while orthophosphate encouraged the growth of more structured, generally thicker, corrosion scales that were effective in limiting Pb release.
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Affiliation(s)
- Yaohuan Gao
- School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, 28 Xianning West Road, Xi'an, Shaanxi, 710049, PR China; Department of Civil and Resource Engineering, Dalhousie University, 1360 Barrington Street, Halifax, Nova Scotia, B3H 4R2, Canada.
| | - Benjamin F Trueman
- Department of Civil and Resource Engineering, Dalhousie University, 1360 Barrington Street, Halifax, Nova Scotia, B3H 4R2, Canada
| | - Graham A Gagnon
- Department of Civil and Resource Engineering, Dalhousie University, 1360 Barrington Street, Halifax, Nova Scotia, B3H 4R2, Canada
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Zhao J, Mowla M, Pan Z, Bao D, Giammar DE, Hu Y, Louie SM. Lead phosphate deposition in porous media and implications for lead remediation. WATER RESEARCH 2022; 214:118200. [PMID: 35228037 DOI: 10.1016/j.watres.2022.118200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 02/13/2022] [Accepted: 02/14/2022] [Indexed: 06/14/2023]
Abstract
Phosphate addition is commonly applied as an effective method to remediate lead contaminated sites via formation of low solubility lead phosphate solids. However, subsequent transport of the lead phosphate particles may impact the effectiveness of this remediation strategy. Hence, this study investigates the mechanisms involved in the aggregation of lead phosphate particles and their deposition in sand columns as a function of typical water chemistry parameters. Clean bed filtration theory was evaluated to predict the particle deposition behavior, using Derjaguin-Landau-Verwey-Overbeek (DLVO) theory to estimate particle-substrate interactions. The observed particle deposition was not predictable from the primary energy barrier in clean bed filtration models, even in simple monovalent background electrolyte (NaNO3), because weak deposition in a secondary energy minimum prevailed even at low ionic strength, and ripening occurred at ionic strengths of 12.5 mM or higher. For aged (aggregated) suspensions, straining also occurred at 12.5 mM or higher. Aggregation and deposition were further enhanced at low total P/Pb ratios (i.e., P/Pb = 1) and in the presence of divalent cations, such as Ca2+ (≥ 0.2 mM), which resulted in less negative particle surface potentials and weaker electrostatic repulsion forces. However, the presence of 5 mg C/L of humic acid induced strong steric or electrosteric repulsion, which hindered particle aggregation and deposition even in the presence of Ca2+. This study demonstrates the importance of myriad mechanisms in lead phosphate deposition and provides useful information for controlling water chemistry in phosphate applications for lead remediation.
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Affiliation(s)
- Juntao Zhao
- Department of Civil & Environmental Engineering, University of Houston, Houston, TX 77004, United States
| | - Marfua Mowla
- Department of Civil & Environmental Engineering, University of Houston, Houston, TX 77004, United States
| | - Zezhen Pan
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200438, China
| | - Daniel Bao
- Department of Civil & Environmental Engineering, University of Houston, Houston, TX 77004, United States
| | - Daniel E Giammar
- Department of Energy, Environmental and Chemical Engineering, Washington University, St. Louis, MO 63130, United States
| | - Yandi Hu
- Department of Civil & Environmental Engineering, University of Houston, Houston, TX 77004, United States; College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China; State Environmental Protection Key Laboratory of All Material Fluxes in River Ecosystems, Beijing 100871, China.
| | - Stacey M Louie
- Department of Civil & Environmental Engineering, University of Houston, Houston, TX 77004, United States.
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Lei S, Hong C, Dong Z, Zhang J, Zhang X, Zhu L, Qiu Y. Pb(II)-mediated precipitate transformation promotes Cr(VI) immobilization by biogenic hydroxyapatite. JOURNAL OF HAZARDOUS MATERIALS 2022; 424:127584. [PMID: 34736214 DOI: 10.1016/j.jhazmat.2021.127584] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 10/17/2021] [Accepted: 10/20/2021] [Indexed: 06/13/2023]
Abstract
In this work, the mechanism of Pb(II)-mediated precipitation transformation to improve the removal of Cr(VI)-oxyanion on biogenic hydroxyapatite (BHAp) were investigated. The Pb(II)-preloading formed pyromorphite [Pb5(PO4)3Cl] precipitate on the BHAp surface (Pb@BHAp), thus causing an increase of 2.2 times in the uptake of Cr(VI) by Pb@BHAp at pH of 2.4. It was primarily due to the dissolution of Pb5(PO4)3Cl accompanied with the release of Pb(II), resulting in the rapid formation of crocoite (PbCrO4). Although the Ksp of Pb5(PO4)3Cl was approximately 23 orders of magnitude lower than that of PbCrO4, Pb(II)-mediated precipitation transformation could still occur. XRD and SEM-EDX analyses demonstrated that the process was a time-dependent that included rapid crystal precipitation in the initial 10 min and subsequent precipitate accumulation for several hours. The Pb(II) released from the dissolution of Pb5(PO4)3Cl was immediately immobilized by Cr(VI); therefore, it did not cause any retention risk of Pb(II) in the solution. Furthermore, a small quantity of Cr(VI) could be reduced to Cr(III) by BHAp, and Cr(III) could enter into the BHAp lattice for the exchange of Ca(II). This study provides a new insight into the resource utilization of Pb-bearing BHAp and a potential method for the successive removal of Pb(II) and Cr(VI).
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Affiliation(s)
- Sicong Lei
- Department of Environmental Science, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Fujian Provincial Key Laboratory of Green Building Technology, Fujian Academy of Building Research Co. Ltd., Fuzhou 350108, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Chengyi Hong
- Department of Environmental Science, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Zhiqiang Dong
- Department of Environmental Science, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Municipal Environmental Protection Engineering Co. Ltd. of CERC Shanghai Group, Shanghai 201906, China
| | - Jichen Zhang
- Department of Environmental Science, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Xiaoxian Zhang
- Department of Environmental Science, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Ling Zhu
- Department of Environmental Science, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Yuping Qiu
- Department of Environmental Science, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
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Yan Y, Wan B, Mansor M, Wang X, Zhang Q, Kappler A, Feng X. Co-sorption of metal ions and inorganic anions/organic ligands on environmental minerals: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 803:149918. [PMID: 34482133 DOI: 10.1016/j.scitotenv.2021.149918] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 07/31/2021] [Accepted: 08/22/2021] [Indexed: 05/21/2023]
Abstract
Co-sorption of metal ions and anions/ligands at the mineral-water interface plays a critical role in regulating the mobility, transport, fate, and bioavailability of these components in natural environments. This review focuses on co-sorption of metal ions and naturally occurring anions/ligands on environmentally relevant minerals. The underlying mechanisms for their interfacial reactions are summarized and the environmental impacts are discussed. Co-sorption mechanisms of these components depend on a variety of factors, such as the identity and properties of minerals, pH, species and concentration of metal ions and anions/ligands, addition sequence of co-sorbed ions, and reaction time. The simultaneous presence of metal ions and anions/ligands alters the initial sorption behaviors with promotive or competitive effects. Promotive effects are mainly attributed to surface electrostatic interactions, ternary surface complexation, and surface precipitation, especially for the co-sorption systems of metal ions and inorganic anions on minerals. Competitive effects involve potential complexation of metal-anions/ligands in solution or their competition for surface adsorption sites. Organic ligands usually increase metal ion sorption on minerals at low pH via forming ternary surface complexes or surface precipitates, but inhibit metal ion sorption via the formation of aqueous complexes at high pH. The different mechanisms may act simultaneously during metal ion and anion/ligand co-sorption on minerals. Finally, the potential application for remediation of metal-contaminated sites is discussed based on the different co-sorption behaviors. Future challenges and topics are raised for metal-anion/ligand co-sorption research.
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Affiliation(s)
- Yupeng Yan
- Key Laboratory of Poyang Lake Watershed Agricultural Resources and Ecology of Jiangxi Province, College of Land Resources and Environment, Jiangxi Agricultural University, Nanchang 330045, People's Republic of China; Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
| | - Biao Wan
- Geomicrobiology, Center for Applied Geosciences, University of Tuebingen, 72076 Tuebingen, Germany.
| | - Muammar Mansor
- Geomicrobiology, Center for Applied Geosciences, University of Tuebingen, 72076 Tuebingen, Germany
| | - Xiaoming Wang
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
| | - Qin Zhang
- Key Laboratory of Poyang Lake Watershed Agricultural Resources and Ecology of Jiangxi Province, College of Land Resources and Environment, Jiangxi Agricultural University, Nanchang 330045, People's Republic of China
| | - Andreas Kappler
- Geomicrobiology, Center for Applied Geosciences, University of Tuebingen, 72076 Tuebingen, Germany; Cluster of Excellence: EXC 2124: Controlling Microbes to Fight Infections, Tübingen, Germany
| | - Xionghan Feng
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.
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Li J, Tian X, Bai R, Xiao X, Yang F, Zhao F. Transforming cerussite to pyromorphite by immobilising Pb(II) using hydroxyapatite and Pseudomonas rhodesiae. CHEMOSPHERE 2022; 287:132235. [PMID: 34826926 DOI: 10.1016/j.chemosphere.2021.132235] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 09/07/2021] [Accepted: 09/09/2021] [Indexed: 06/13/2023]
Abstract
Lead (Pb) pollution has become one of the most serious environmental problems in recent decades. However, there are few remediation technologies for insoluble cerussite (PbCO3), which are common in the environment and have high bioavailability. In this study, the immobilisation of Pb(II) released from PbCO3 by Pseudomonas rhodesiae HP-7 isolated from Pb-contaminated soil was studied. The results showed that hydroxyapatite and PbCO3 were dissolved by the organic acids secreted by the HP-7 strain, and then the dissolved Pb2+ and H2PO4- reacted to form low bioavailable Pb5(PO4)3Cl precipitate. XRD and mass conservation calculations showed that 85.7% of PbCO3 was transformed to Pb5(PO4)3Cl when P:Pb was 9:5. Our research showed that the HP-7 strain and hydroxyapatite could reduce the bioavailability of Pb(II) in PbCO3, which could be used for the remediation of Pb-polluted environments.
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Affiliation(s)
- Junpeng Li
- CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaochun Tian
- CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China
| | - Rui Bai
- CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaofeng Xiao
- CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Fan Yang
- CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Feng Zhao
- CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China.
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Pb Mineral Precipitation in Solutions of Sulfate, Carbonate and Phosphate: Measured and Modeled Pb Solubility and Pb2+ Activity. MINERALS 2021. [DOI: 10.3390/min11060620] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Lead (Pb) solubility is commonly limited by dissolution–precipitation reactions of secondary mineral phases in contaminated soils and water. In the research described here, Pb solubility and free Pb2+ ion activities were measured following the precipitation of Pb minerals from aqueous solutions containing sulfate or carbonate in a 1:5 mole ratio in the absence and presence of phosphate over the pH range 4.0–9.0. Using X-ray diffraction and Fourier-transform infrared spectroscopic analysis, we identified anglesite formed in sulfate-containing solutions at low pH. At higher pH, Pb carbonate and carbonate-sulfate minerals, hydrocerussite and leadhillite, were formed in preference to anglesite. Precipitates formed in the Pb-carbonate systems over the pH range of 6 to 9 were composed of cerussite and hydrocerussite, with the latter favored only at the highest pH investigated. The addition of phosphate into the Pb-sulfate and Pb-carbonate systems resulted in the precipitation of Pb3(PO4)2 and structurally related pyromorphite minerals and prevented Pb sulfate and carbonate mineral formation. Phosphate increased the efficiency of Pb removal from solution and decreased free Pb2+ ion activity, causing over 99.9% of Pb to be precipitated. Free Pb2+ ion activities measured using the ion-selective electrode revealed lower values than predicted from thermodynamic constants, indicating that the precipitated minerals may have lower KSP values than generally reported in thermodynamic databases. Conversely, dissolved Pb was frequently greater than predicted based on a speciation model using accepted thermodynamic constants for Pb ion-pair formation in solution. The tendency of the thermodynamic models to underestimate Pb solubility while overestimating free Pb2+ activity in these systems, at least in the higher pH range, indicates that soluble Pb ion-pair formation constants and KSP values need correction in the models.
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Landrot G, Khaokaew S. Determining the fate of lead (Pb) and phosphorus (P) in alkaline Pb-polluted soils amended with P and acidified using multiple synchrotron-based techniques. JOURNAL OF HAZARDOUS MATERIALS 2020; 399:123037. [PMID: 32526425 DOI: 10.1016/j.jhazmat.2020.123037] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 05/11/2020] [Accepted: 05/23/2020] [Indexed: 06/11/2023]
Abstract
The effect of acidification on lead (Pb) and phosphorus (P) speciation in alkaline Pb-polluted soils that are amended with P to stabilize Pb is still unclear. It was studied in three alkaline Pb-polluted soils containing specific amounts of Soil Organic Matter (SOM), using multiple synchrotron-based techniques, i.e. bulk X-ray Absorption Fine Structure (XAFS) spectroscopy at Pb LIII- and P K-edges, micro-X-ray Fluorescence (μ-XRF), and micro-X-ray Diffraction (μ-XRD). These techniques provided unambiguous evidences that the formation of pyromorphite, i.e. the desired Pb stabilized chemical form, was severely limited in the acidified soil samples amended with fish bones or phosphoric acid (H3PO4). Most Pb present in the H3PO4-amended soil samples did not convert to pyromorphite due to Pb and P leaching and PbSO4(s) formation. In contrast, most Pb present in the fish bone-amended soil samples was unaffected by acidification and did not convert to pyromorphite as it was inaccessible to soil solution or retained by SOM, similarly to P. Additionally, Pb-SOM association increased with increasing SOM content. Results had important implications on the applicability of the P-based method to stabilize Pb within the first centimeters below surface of Pb-polluted alkaline soils, which potentially represent the most hazardous part of these soils.
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Affiliation(s)
- Gautier Landrot
- Synchrotron SOLEIL, L'Orme des Merisiers, 91190, Saint Aubin, France.
| | - Saengdao Khaokaew
- Department of Soil Science, Faculty of Agriculture, Kasetsart University, 50 Ngam Wong Wan Rd, Lat Yao Chatuchak, Bangkok 10900, Thailand.
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10
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Wang L, Putnis CV. Dissolution and Precipitation Dynamics at Environmental Mineral Interfaces Imaged by In Situ Atomic Force Microscopy. Acc Chem Res 2020; 53:1196-1205. [PMID: 32441501 DOI: 10.1021/acs.accounts.0c00128] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Chemical reactions at the mineral-solution interface control important interfacial processes, such as geochemical element cycling, nutrient recovery from eutrophicated waters, sequestration of toxic contaminants, and geological carbon storage by mineral carbonation. By time-resolved in situ imaging of nanoscale mineral interfacial reactions, it is possible to clarify the mechanisms governing mineral-fluid reactions.In this Account, we present a concise summary of this topic that addresses a current challenge at the frontier of understanding mineral interfaces and their importance to a wide range of mineral re-equilibration processes in the presence of a fluid aqueous phase. We have used real-time nanoscale imaging of liquid-cell atomic force microscopy (AFM) to observe the in situ coupling of the dissolution-precipitation process, whereby the dissolution of a parent mineral phase is coupled at mineral interfaces with the precipitation of another product phase, chemically different from the parent. These nanoscale observations allow for the identification of dissolution and growth rates through systematically investigating various minerals, including calcite (CaCO3), siderite (FeCO3), cerussite (PbCO3), magnesite (MgCO3), dolomite (CaMg(CO3)2), brushite (CaHPO4·2H2O), brucite (Mg(OH)2), portlandite (Ca(OH)2), and goethite (α-FeOOH), in various reacting aqueous fluids containing solution species, such as arsenic, phosphate, organo- or pyrophosphate, CO2, selenium, lead, cadmium, iron, chromium, and antimony. We detected the in situ replacement of these parent mineral phases by product phases, identified through a variety of analytical methods such as Raman spectroscopy, high-resolution transmission electron microscopy, and various X-ray techniques, as well as modeling by geochemical simulation using PHREEQC. As a consequence of the coupled processes, sequestration of toxic elements and hazardous species and inorganic and organic carbon, and limiting or promoting recovery of nutrients can be achieved at nano- and macroscopic scales.We also used in situ AFM to quantitatively measure the retreat rates of molecular steps and directly observe the morphology changes of dissolution etch pits on calcium phosphates in organic acid solutions present in most rhizosphere environments. By molecular modeling using density functional theory (DFT), we explain the origin of dissolution etch pit evolution through specific stereochemistry and molecular recognition and provide an energetic basis by calculating the binding energies of chemical functionalities on organic acids to direction-specific steps on mineral surfaces. In addition, we further quantified precipitation kinetics of calcium phosphates (Ca-P's) on typical mineral surfaces at the nanoscale in environmentally relevant solutions with various organic molecules, by measurements obtained from sequential images obtained by liquid-cell AFM. In situ dynamic force spectroscopy (DFS) was used to determine binding energies of single-molecules with different chemical functionalities found in natural organic matter at mineral-fluid interfaces. Quantifying molecular organo-mineral bonding or binding energies mechanistically explains phosphate precipitation and transformation. From DFS measurements, molecular-scale interactions of mineral-natural organic matter (DNA, proteins, and polysaccharides) associations were determined. With this powerful tool, single-molecule determinations of polysaccharide-amorphous iron oxide or hematite interactions provided the mechanistic origin of the phase- or facet-dependent adsorption. These systematic investigations and findings significantly contribute to a more quantitative prediction of the fate of nutrients and contaminants, chemical element cycling, and potential geological carbon capture and nuclear waste storage in aqueous environments.
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Affiliation(s)
- Lijun Wang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Christine V. Putnis
- Institut für Mineralogie, University of Münster, 48149 Münster, Germany
- School of Molecular and Life Science, Curtin University, Perth, WA 6845, Australia
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11
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Improved understanding of the sulfidization mechanism in cerussite flotation: An XPS, ToF-SIMS and FESEM investigation. Colloids Surf A Physicochem Eng Asp 2020. [DOI: 10.1016/j.colsurfa.2020.124508] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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12
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Xu JC, Huang LM, Chen C, Wang J, Long XX. Effective lead immobilization by phosphate rock solubilization mediated by phosphate rock amendment and phosphate solubilizing bacteria. CHEMOSPHERE 2019; 237:124540. [PMID: 31549654 DOI: 10.1016/j.chemosphere.2019.124540] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 08/06/2019] [Accepted: 08/07/2019] [Indexed: 06/10/2023]
Abstract
Lead can be immobilized in contaminated soils by phosphate rock (PR) amendment, but its efficiency is generally limited by low solubility of PR. Our study aimed to elucidate whether phosphate solubilizing bacteria (PSB) can promote Pb immobilization through PR solubilization. Results showed that P. ananatis HCR2 and B. thuringiensis GL-1 could effectively solubilize PR by producing citric, glucose, and α-Ketoglutaric acids. In broth assay, phosphate solubilized from PR by PSB rapidly reacted with Pb2+ and formed insoluble lead compounds, as confirmed by scanning electron microscope, energy dispersive X-ray, and X-ray photoelectron spectroscopy. Pot experiment using lettuce (Lactuca sativa L.) and diffusive gradients in thin films (DGT) verified the effectiveness of soil remediation using PR amendment and PSB inoculation, as plant shoot biomass and net photosynthetic rate as well as soil bioavailable phosphate concentration have significantly increased, while the phytoavailability of Pb, Cd, and Zn greatly reduced. This study suggested that PR amendment combined with PSB inoculation could be applied for remediation of agricultural fields contaminated with multiple heavy metals.
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Affiliation(s)
- Jia-Cheng Xu
- Key Laboratory of Soil Environment and Waste Reuse in Agriculture of Guangdong Higher Education Institutes, College of Natural Resources and Environment, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Li-Min Huang
- Key Laboratory of Soil Environment and Waste Reuse in Agriculture of Guangdong Higher Education Institutes, College of Natural Resources and Environment, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Chengyu Chen
- Key Laboratory of Soil Environment and Waste Reuse in Agriculture of Guangdong Higher Education Institutes, College of Natural Resources and Environment, South China Agricultural University, Guangzhou, Guangdong 510642, China.
| | - Jing Wang
- Key Laboratory of Soil Environment and Waste Reuse in Agriculture of Guangdong Higher Education Institutes, College of Natural Resources and Environment, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Xin-Xian Long
- Key Laboratory of Soil Environment and Waste Reuse in Agriculture of Guangdong Higher Education Institutes, College of Natural Resources and Environment, South China Agricultural University, Guangzhou, Guangdong 510642, China.
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13
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Di Lorenzo F, Ruiz-Agudo C, Churakov SV. The key effects of polymorphism during PbII uptake by calcite and aragonite. CrystEngComm 2019. [DOI: 10.1039/c9ce01040h] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The efficiency of Pb uptake by CaCO3 is different for calcite and aragonite due to surface passivation.
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Affiliation(s)
- Fulvio Di Lorenzo
- Institute of Geological Sciences
- University of Bern
- Bern 3012
- Switzerland
| | | | - Sergey V. Churakov
- Institute of Geological Sciences
- University of Bern
- Bern 3012
- Switzerland
- Laboratory for Waste Management
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14
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Zhao J, Giammar DE, Pasteris JD, Dai C, Bae Y, Hu Y. Formation and Aggregation of Lead Phosphate Particles: Implications for Lead Immobilization in Water Supply Systems. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:12612-12623. [PMID: 30252454 DOI: 10.1021/acs.est.8b02788] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Phosphate is commonly added to drinking water to inhibit lead release from lead service lines and lead-containing materials in premise plumbing. Phosphate addition promotes the formation of lead phosphate particles, and their aggregation behaviors may affect their transport in pipes. Here, lead phosphate formation and aggregation were studied under varied aqueous conditions typical of water supply systems. Under high aqueous PO4/Pb molar ratios (>1), phosphate adsorption made the particles more negatively charged. Therefore, enhanced stability of lead phosphate particles was observed, suggesting that although addition of excess phosphate can lower the dissolved lead concentrations in tap water, it may increase concentrations of particulate lead. Adsorption of divalent cations (Ca2+ and Mg2+) onto lead phosphate particles neutralized their negative surface charges and promoted their aggregation at pH 7, indicating that phosphate addition for lead immobilization may be more efficient in harder waters. The presence of natural organic matter (NOM, ≥ 0.05 mg C/L humic acid and ≥ 0.5 mg C/L fulvic acid) retarded particle aggregation at pH 7. Consequently, removal of organic carbon during water treatment to lower the formation of disinfection-byproducts (DBPs) may have the additional benefit of minimizing the mobility of lead-containing particles. This study provided insight into fundamental mechanisms controlling lead phosphate aggregation. Such understanding is helpful to understand the observed trends of total lead in water after phosphate addition in both field and pilot-scale lead pipe studies. Also, it can help optimize lead immobilization by better controlling the water chemistry during phosphate addition.
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Affiliation(s)
- Juntao Zhao
- Department of Civil & Environmental Engineering , University of Houston , Houston , Texas 77004 , United States
| | - Daniel E Giammar
- Department of Energy, Environmental, and Chemical Engineering , Washington University in St. Louis , St. Louis , Missouri 63130 , United States
| | - Jill D Pasteris
- Department of Earth and Planetary Sciences , Washington University in St. Louis , St. Louis , Missouri 63130 , United States
| | - Chong Dai
- Department of Civil & Environmental Engineering , University of Houston , Houston , Texas 77004 , United States
| | - Yeunook Bae
- Department of Energy, Environmental, and Chemical Engineering , Washington University in St. Louis , St. Louis , Missouri 63130 , United States
| | - Yandi Hu
- Department of Civil & Environmental Engineering , University of Houston , Houston , Texas 77004 , United States
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15
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Metal Sequestration through Coupled Dissolution–Precipitation at the Brucite–Water Interface. MINERALS 2018. [DOI: 10.3390/min8080346] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The increasing release of potentially toxic metals from industrial processes can lead to highly elevated concentrations of these metals in soil, and ground- and surface-waters. Today, metal pollution is one of the most serious environmental problems and thus, the development of effective remediation strategies is of paramount importance. In this context, it is critical to understand how dissolved metals interact with mineral surfaces in soil–water environments. Here, we assessed the processes that govern the interactions between six common metals (Zn, Cd, Co, Ni, Cu, and Pb) with natural brucite (Mg(OH)2) surfaces. Using atomic force microscopy and a flow-through cell, we followed the coupled process of brucite dissolution and subsequent nucleation and growth of various metal bearing precipitates at a nanometer scale. Scanning electron microscopy and Raman spectroscopy allowed for the identification of the precipitates as metal hydroxide phases. Our observations and thermodynamic calculations indicate that this coupled dissolution–precipitation process is governed by a fluid boundary layer at the brucite–water interface. Importantly, this layer differs in composition and pH from the bulk solution. These results contribute to an improved mechanistic understanding of sorption reactions at mineral surfaces that control the mobility and fate of toxic metals in the environment.
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16
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Zhai H, Wang L, Qin L, Zhang W, Putnis CV, Putnis A. Direct Observation of Simultaneous Immobilization of Cadmium and Arsenate at the Brushite-Fluid Interface. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:3493-3502. [PMID: 29488373 DOI: 10.1021/acs.est.7b06479] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Cadmium (Cd2+) and Arsenate (As5+) are the main toxic elements in soil environments and are easily taken up by plants. Unraveling the kinetics of the adsorption and subsequent precipitation/immobilization on mineral surfaces is of considerable importance for predicting the fate of these dissolved species in soils. Here we used in situ atomic force microscopy (AFM) to image the dissolution on the (010) face of brushite (dicalcium phosphate dihydrate, CaHPO4·2H2O) in CdCl2- or Na2HAsO4-bearing solutions over a broad pH and concentration range. During the initial dissolution processes, we observed that Cd or As adsorbed on step edges to modify the morphology of etch pits from the normal triangular shape to a four-sided trapezium. Following extended reaction times, the respective precipitates were formed on brushite through a coupled dissolution-precipitation mechanism. In the presence of both CdCl2 and Na2HAsO4 in reaction solutions at pH 8.0, high-resolution transmission electron microscopy (HRTEM) showed a coexistence of both amorphous and crystalline phases, i.e., a mixed precipitate of amorphous and crystalline Cd(5- x)Ca x(AsO4)(3- y)(PO4) yOH phases was detected. These direct dynamic observations of the transformation of adsorbed species to surface precipitates may improve the mechanistic understanding of the calcium phosphate mineral interface-induced simultaneous immobilization of both Cd and As and subsequent sequestration in diverse soils.
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Affiliation(s)
- Hang Zhai
- College of Resources and Environment , Huazhong Agricultural University , Wuhan 430070 , P. R. China
| | - Lijun Wang
- College of Resources and Environment , Huazhong Agricultural University , Wuhan 430070 , P. R. China
| | - Lihong Qin
- College of Resources and Environment , Huazhong Agricultural University , Wuhan 430070 , P. R. China
| | - Wenjun Zhang
- College of Resources and Environment , Huazhong Agricultural University , Wuhan 430070 , P. R. China
| | - Christine V Putnis
- Institut für Mineralogie , University of Münster , 48149 Münster , Germany
| | - Andrew Putnis
- Institut für Mineralogie , University of Münster , 48149 Münster , Germany
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17
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Wang M, Zhang Z, Ren J, Zhang C, Li C, Guo G, Li F. Microscopic evidence for humic acid induced changes in lead immobilization by phosphate in a counterdiffusion system. JOURNAL OF HAZARDOUS MATERIALS 2017; 330:46-51. [PMID: 28208092 DOI: 10.1016/j.jhazmat.2017.02.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 01/21/2017] [Accepted: 02/06/2017] [Indexed: 06/06/2023]
Abstract
Abatement of lead (Pb) contamination in soil via chemical immobilization can reduce potential risks but is influenced by soil organic matter. The aim of this study was to observe and understand the influence of organic matter on Pb immobilization by phosphate. For this purpose, humic acid (HA) was introduced into a counterdiffusion system to mimic ionic reactions of the mineralization processes between the pollutant (Pb) and amendment agent (phosphate) in soil system, and were characterized jointly by in situ optical microscopy and ex situ XRD, SEM, TEM, and LSCM. The results indicate that lead immobilization in the counterdiffusion system involves a time-dependent crystallization process and that supersaturation occurs at nearly central region of the reaction zone. Entrapped HA had influence on crystal growth and size, causing more fragmented crystal morphology with increasing HA content, which can be explained by HA wrapping of the nucleation products and subsequent inhibition of reactions and crystal growth, as indicated by TEM and LSCM images. Mineral conversion from secondary lead orthophosphates to pyromorphite implies the promotion of more stable minerals. This approach provides evidence for a more intuitive understanding of the effects of HA on the immobilization of lead by phosphates.
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Affiliation(s)
- Mei Wang
- College of Water Sciences, Beijing Normal University, Beijing 100875, China; Department of Soil Pollution Control, State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
| | - Zhuo Zhang
- College of Water Sciences, Beijing Normal University, Beijing 100875, China; Department of Soil Pollution Control, State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
| | - Jie Ren
- College of Water Sciences, Beijing Normal University, Beijing 100875, China; Department of Soil Pollution Control, State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
| | - Chao Zhang
- Department of Soil Pollution Control, State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
| | - Chunping Li
- State Key Laboratory of Solid Waste Reuse for Building Materials, Beijing Building Materirals Academy of Science Research, Beijing 100041, China
| | - Guanlin Guo
- Department of Soil Pollution Control, State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
| | - Fasheng Li
- College of Water Sciences, Beijing Normal University, Beijing 100875, China; Department of Soil Pollution Control, State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
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18
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Wang Y, Dong X, Cui J, Wei Z, Wang X. Effect of hydroxyapatite particle size on the formation of chloropyromorphite in anglesite–hydroxyapatite suspensions. RSC Adv 2017. [DOI: 10.1039/c6ra28770k] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
As the HAP particle size was decreased, the surfaces of the undissolved HAPs were coated by newly formed chloropyromorphite at a higher pH value, and particularly at a high P : Pb ratio, indicating that HAP particle size was a rate-limiting factor.
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Affiliation(s)
- Yu Wang
- Anhui Key Laboratory of Functional Coordination Compounds
- School of Resources and Environments
- Anqing Normal University
- Anqing
- P. R. China
| | - Xiaoqing Dong
- Anhui Key Laboratory of Functional Coordination Compounds
- School of Resources and Environments
- Anqing Normal University
- Anqing
- P. R. China
| | - Jing Cui
- Department of Environmental Science
- Nanjing Normal University
- Nanjing
- P. R. China
| | - Zhenggui Wei
- Department of Environmental Science
- Nanjing Normal University
- Nanjing
- P. R. China
| | - Xiaohong Wang
- Anhui Key Laboratory of Functional Coordination Compounds
- School of Resources and Environments
- Anqing Normal University
- Anqing
- P. R. China
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19
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Sanderson P, Naidu R, Bolan N. The effect of environmental conditions and soil physicochemistry on phosphate stabilisation of Pb in shooting range soils. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2016; 170:123-30. [PMID: 26812009 DOI: 10.1016/j.jenvman.2016.01.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 01/14/2016] [Accepted: 01/15/2016] [Indexed: 05/27/2023]
Abstract
The stabilisation of Pb in the soil by phosphate is influenced by environmental conditions and physicochemical properties of the soils to which it is applied. Stabilisation of Pb by phosphate was examined in four soils under different environmental conditions. The effect of soil moisture and temperature on stabilisation of Pb by phosphate was examined by measurement of water extractable and bioaccessible Pb, sequential fractionation and X-ray absorption spectroscopy. The addition of humic acid, ammonium nitrate and chloride was also examined for inhibition or improvement of Pb stability with phosphate treatment. The effect of moisture level varied between soils. In soil MB and DA a soil moisture level of 50% water holding capacity was sufficient to maximise stabilisation of Pb, but in soil TV and PE reduction in bioaccessible Pb was inhibited at this moisture level. Providing moisture at twice the soil water holding capacity did not enhance the effect of phosphate on Pb stabilisation. The difference of Pb stability as a result of incubating phosphate treated soils at 18 °C and 37 °C was relatively small. However wet-dry cycles decreased the effectiveness of phosphate treatment. The reduction in bioaccessible Pb obtained was between 20 and 40% with the most optimal treatment conditions. The reduction in water extractable Pb by phosphate was substantial regardless of incubation conditions and the effect of different temperature and soil moisture regimes was not significant. Selective sequential extraction showed phosphate treatment converted Pb in fraction 1 (exchangeable, acid and water soluble) to fraction 2 (reducible). There were small difference in fraction 4 (residual) Pb and fraction 1 as a result of treatment conditions. X-ray absorption spectroscopy of stabilised PE soil revealed small differences in Pb speciation under varying soil moisture and temperature treatments. The addition of humic acid and chloride produced the greatest effect on Pb speciation in phosphate treated soils.
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Affiliation(s)
- Peter Sanderson
- Global Centre for Environmental Remediation, University of Newcastle and CRC for Contamination Assessment and Remediation of the Environment (CRC CARE), Australia; Previous Address: Centre for Environmental Risk Assessment and Remediation, University of South Australia, University Parade, Mawson Lakes, SA 5095, Australia
| | - Ravi Naidu
- Global Centre for Environmental Remediation, University of Newcastle and CRC for Contamination Assessment and Remediation of the Environment (CRC CARE), Australia; Previous Address: Centre for Environmental Risk Assessment and Remediation, University of South Australia, University Parade, Mawson Lakes, SA 5095, Australia
| | - Nanthi Bolan
- Global Centre for Environmental Remediation, University of Newcastle and CRC for Contamination Assessment and Remediation of the Environment (CRC CARE), Australia; Previous Address: Centre for Environmental Risk Assessment and Remediation, University of South Australia, University Parade, Mawson Lakes, SA 5095, Australia
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