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Guo Q, Yu D, Yang J, Zhao T, Yu D, Li L, Wang D. A novel sequential extraction method for the measurement of Cr(VI) and Cr(III) species distribution in soil: New insights into the chromium speciation. JOURNAL OF HAZARDOUS MATERIALS 2024; 480:135864. [PMID: 39298968 DOI: 10.1016/j.jhazmat.2024.135864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2024] [Revised: 08/20/2024] [Accepted: 09/15/2024] [Indexed: 09/22/2024]
Abstract
The distribution characteristics of Cr(VI) species in contaminated soil is crucial for soil remediation; however, there is currently a lack of methods for analysing anionic Cr(VI) species in soil. This study has developed a novel sequential extraction method for speciation of Cr(VI) and Cr(III). Besides extraction experiments, simulated chromium species were prepared to verify the presence of proposed chromium species. The results show that Cr(VI) species in soil can be categorized into water-soluble Cr(VI), electrostatically adsorbed Cr(VI), Cr(VI) specifically adsorbed by minerals containing exchangeable Ca2+, Cr(VI) specifically adsorbed by hydrous metal oxides, calcium chromate Cr(VI) and stable complexed adsorption Cr(VI). These Cr(VI) species can be selectively extracted by specific solutions through ion exchange or weak acid dissolution. The most stable Cr(VI) species is Cr(VI) complexed by hydrous iron oxides through bidentate ligand binding; only by dissolution of hydrous iron oxides can this Cr(VI) species be leached. The distribution of Cr(VI) species is closely linked to particular soil compositions including exchangeable Ca2+ and hydrous iron oxides which determinate the Cr(VI) adsorption in soil. Cr(III) species comprise Fe-Cr coprecipitate hydroxides Cr(III), Fe-Mn oxide-bound Cr(III), organic matter-bound Cr(III) and residual Cr(III). Their distribution depends on the types of reductants present in the soil.
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Affiliation(s)
- Qian Guo
- College of Resources and Environment, Southwest University, Chongqing 400715, PR China
| | - Dongmei Yu
- College of Resources and Environment, Southwest University, Chongqing 400715, PR China
| | - Jing Yang
- Jiangbei District Ecological Environment Monitoring Station, Chongqing Bureau of Ecology and Environment, Chongqing 400025, PR China
| | - Ting Zhao
- College of Resources and Environment, Southwest University, Chongqing 400715, PR China
| | - Dan Yu
- College of Resources and Environment, Southwest University, Chongqing 400715, PR China
| | - Lei Li
- College of Resources and Environment, Southwest University, Chongqing 400715, PR China; Key Laboratory of the Evaluation and Monitoring of Southwest Land Resources (Ministry of Education), Sichuan Normal University, Chengdu 610068, PR China.
| | - Duanjie Wang
- College of Resources and Environment, Southwest University, Chongqing 400715, PR China
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2
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Zhao S, Chen K, Xiong B, Guo C, Dang Z. Prediction of adsorption of metal cations by clay minerals using machine learning. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 924:171733. [PMID: 38492590 DOI: 10.1016/j.scitotenv.2024.171733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 02/24/2024] [Accepted: 03/13/2024] [Indexed: 03/18/2024]
Abstract
Adsorption of heavy metals by clay minerals occurs widely at the solid-liquid interface in natural environments, and in this paper, the phenomenon of adsorption of Cd2+, Cu2+, Pb2+, Zn2+, Ni2+ and Co2+ by montmorillonite, kaolinite and illite was simulated using machine learning. We firstly used six machine learning models including Random Forest(R), Extremely Forest(E), Gradient Boosting Decision Tree(G), Extreme Gradient Boosting(X), Light Gradient Boosting(LGB) and Category Boosting(CAT) to feature engineer the metal cations and the parameters of the minerals, and based on the feature engineering results, we determined the first order hydrolysis constant(log K), solubility product constant(SPC), and higher hydrolysis constant (HHC) as the descriptors of the metal cations, and site density(SD) and cation exchange capacity(CEC) as the descriptors of the clay minerals. After comparing the predictive effects of different data cleaning methods (pH50 method, Box method and pH50-Box method) and six model combinations, it was finally concluded that the best simulation results could be achieved by using the pH 50-Box method for data cleaning and Extreme Gradient Boosting for modelling (RMSE = 4.158 %, R2 = 0.977). Finally, model interpretation was carried out using Shapley explanation plot (SHAP) and partial dependence plot(PDP) to analyse the potential connection between each input variable and the output results. This study combines machine learning with geochemical analysis of the mechanism of heavy metal adsorption by clay minerals, which provides a different research perspective from the traditional surface complexation model.
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Affiliation(s)
- Shoushi Zhao
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou 510006, PR China
| | - Kai Chen
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou 510006, PR China
| | - Beiyi Xiong
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou 510006, PR China
| | - Chuling Guo
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou 510006, PR China.
| | - Zhi Dang
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou 510006, PR China
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3
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Wang W, Yang L, Gao D, Yu M, Jiang S, Li J, Zhang J, Feng X, Tan W, Liu F, Yin M, Yin H. Characteristics of iron (hydr)oxides and Cr(VI) retention mechanisms in soils from tropical and subtropical areas of China. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133107. [PMID: 38043424 DOI: 10.1016/j.jhazmat.2023.133107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 10/24/2023] [Accepted: 11/26/2023] [Indexed: 12/05/2023]
Abstract
Though both iron (hydr)oxides and soil organic matter (SOM) significantly influence heavy metal behaviors in soils, studies on the characteristics of natural minerals and the synergic effects of the two on Cr(VI) transformation are limited. This study investigated Cr(VI) retention mechanisms in four soils from tropical and subtropical regions of China based on a comprehensive characterization of Fe (hydr)oxides. These soils exhibited varying quantities of hematite, ferrihydrite and goethite, with distinct Al substitution levels and varied exposed crystallographic facets. Adsorption experiments revealed a positive correlation between Fe (hydr)oxide content and Cr(VI) fixation amount on colloid, which was influenced by the mineral types, Al substitution levels and facet exposures. Further, Cr(VI) was sequestered on soil by adsorption and reduction. In soils enriched with crystalline Fe (hydr)oxides, Cr(VI) reduction was primarily governed by SOM, while in soils enriched with poorly crystalline Fe (hydr)oxides, mineral-associated Fe(II) also contributed to Cr(VI) reduction. Aging experiments demonstrated that SOM and mineral-associated Fe(II) expedited Cr (VI) passivation and diminished the Cr leaching. These results improve our understanding of natural Fe (hydr)oxide structures and their impact on Cr(VI) behavior in soils, and shed light on complex soil-contaminant interactions and remediation of Cr(VI) polluted soils.
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Affiliation(s)
- Wentao Wang
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture and Rural affairs, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China; State Environmental Protection Key Laboratory of Soil Health and Green Remediation, Ministry of Ecology and Environment, Wuhan 430070, China
| | - Liu Yang
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture and Rural affairs, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Dong Gao
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture and Rural affairs, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Minghao Yu
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture and Rural affairs, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Shuqi Jiang
- Faculty of Resources and Environmental Science, Hubei University, Wuhan 430070, China
| | - Jiangshan Li
- State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Jing Zhang
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100039, China
| | - Xionghan Feng
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture and Rural affairs, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China; State Environmental Protection Key Laboratory of Soil Health and Green Remediation, Ministry of Ecology and Environment, Wuhan 430070, China
| | - Wenfeng Tan
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture and Rural affairs, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China; State Environmental Protection Key Laboratory of Soil Health and Green Remediation, Ministry of Ecology and Environment, Wuhan 430070, China
| | - Fan Liu
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture and Rural affairs, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China; State Environmental Protection Key Laboratory of Soil Health and Green Remediation, Ministry of Ecology and Environment, Wuhan 430070, China
| | - Ming Yin
- Shiyan Ecological Environment Monitoring Center of Hubei Provincial Department of Ecology and Environment, Shiyan 442000, China.
| | - Hui Yin
- Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture and Rural affairs, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China; State Environmental Protection Key Laboratory of Soil Health and Green Remediation, Ministry of Ecology and Environment, Wuhan 430070, China.
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4
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Barreto MSC, Elzinga EJ, Kubicki JD, Sparks DL. A multi-scale assessment of the impact of salinity on the desorption of chromate from hematite: Sea level rise implications. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133041. [PMID: 38043423 DOI: 10.1016/j.jhazmat.2023.133041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 11/08/2023] [Accepted: 11/17/2023] [Indexed: 12/05/2023]
Abstract
The solubility and transport of Cr(VI) is primarily controlled by adsorption-desorption reactions at the surfaces of soil minerals such as iron oxides. Environmental properties such as pH, ionic strength, and ion competition are expected to affect the mobility and fate of Cr(VI). Sea level rise (SLR), and consequent seawater intrusion, is creating a new biogeochemical soil environment at coastal margins, potentially impacting Cr(VI) retention at contaminated sites. We employed in-situ ATR-FTIR spectroscopy and DFT calculations to investigate at the molecular level the adsorption of Cr(VI) on the hematite surface and its desorption by sulfate, as a function of pH and ionic strength. We further used a batch experiment to assess Cr(VI) desorption at varying artificial seawater (ASW) concentrations. IR results demonstrate the complexity of Cr(VI) adsorption, showing a combination of monodentate inner-sphere complexation at high pH and dichromate outer-sphere (∼75%) at low pH. The Cr(VI)-complexes exhibited desorption induced by increasing pH values (58% of desorption) and sulfate competition (∼40% desorption). ASW desorbed ∼20% more Cr(VI), even at just 1% concentration. Our findings provide insight into Cr(VI)-adsorption complexation that controls the retention and remobilization of Cr(VI) on Fe-oxide minerals. The results point to an elevated risk of Cr(VI) mobilization in contaminated soils affected by SLR.
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Affiliation(s)
| | - Evert J Elzinga
- Department of Earth & Environmental Sciences, Rutgers University, Newark, NJ, USA
| | - James D Kubicki
- Department of Earth, Environmental & Resource Sciences, The University of Texas at El Paso, El Paso, TX, USA
| | - Donald L Sparks
- Department of Plant & Soil Sciences, University of Delaware, Newark, DE, USA
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5
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Han SC, Chang E, Zechel S, Bok F, Zavarin M. Application of community data to surface complexation modeling framework development: Iron oxide protolysis. J Colloid Interface Sci 2023; 648:1015-1024. [PMID: 37343488 DOI: 10.1016/j.jcis.2023.06.054] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 05/16/2023] [Accepted: 06/09/2023] [Indexed: 06/23/2023]
Abstract
This study presents a comprehensive community data-driven surface complexation modeling framework for simulating potentiometric titration of mineral surfaces. Compiled community data for ferrihydrite, goethite, hematite, and magnetite are fit to produce representative protolysis constants that can reproduce potentiometric titration data collected from multiple literature sources. Using this framework, the impact of surface complexation model type and surface site density (SSD) on the fit quality and protolysis constants can be readily evaluated. For example, the non-electrostatic model yielded a poor data fit compared to diffuse double layer model and constant capacitance models due to the absence of known surface charge effects. Regardless of the choice of iron oxide mineral, pKa1 decreased with increasing SSD while the opposite tendency was observed for pKa2. This newly developed framework demonstrates a method to reconcile community data-wide potentiometric titration data using Findable, Accessible, Interoperable, Reusable data principles to produce mineral protolysis constants that improve robustness of surface complexation models for applications in metal sorption and reactive transport modeling. The framework is readily expandable (as community data increase) and extensible (as the number of minerals increase). The framework provides a path forward for developing self-consistent, comprehensive, and updateable surface complexation databases for surface complexation and reactive transport modeling.
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Affiliation(s)
- Sol-Chan Han
- Seaborg Institute, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550, United States
| | - Elliot Chang
- Seaborg Institute, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550, United States
| | - Susanne Zechel
- Institute of Resource Ecology, Actinide Thermodynamics Department (FWOA), Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Frank Bok
- Institute of Resource Ecology, Actinide Thermodynamics Department (FWOA), Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Mavrik Zavarin
- Seaborg Institute, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550, United States.
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6
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Yang J, Guo Q, Li L, Wang R, Chen Y, Wang X. Insights into the evolution of Cr(VI) species in long-term hexavalent chromium contaminated soil. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 858:160149. [PMID: 36372161 DOI: 10.1016/j.scitotenv.2022.160149] [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: 08/29/2022] [Revised: 10/21/2022] [Accepted: 11/08/2022] [Indexed: 06/16/2023]
Abstract
Compare to the content of Cr(VI), the distribution of specific Cr(VI) species in soil is rarely paid attention to, which may lead to an inaccurate environmental risk assessment of Cr(VI) contaminated soil or inability to meet stringent requirement for soil remediation. Herein, to reveal the primary mechanisms and factors controlling the evolution of Cr(VI) species in soil, the distribution of Cr(VI) and Cr(III) species in soils with different particle sizes and textures was systematically investigated by using a modified sequential extraction procedure and spectroscopy characterizations (e.g., SEM-EDS mapping). The results show that a significant proportion of Cr(VI) can be captured by minerals containing exchangeable calcium ions and metal oxide hydrates in the soil, forming a relatively stable adsorbed Cr(VI). Also, a small fraction of Cr(VI) can precipitate as calcium chromate with free calcium ion which is the most stable Cr(VI) species in the soil. The majority of Cr(VI) discharged into soil tends to be reduced by ferrous ions or minerals containing ferrous ions with a product of Fe(III)-Cr(III) coprecipitate. Therefore, the speciation of Cr in the soil is closely correlated to Fe and Ca. After the equilibrium of adsorption, precipitation, and reduction reactions of Cr(VI), the rest of Cr(VI) retains as the form of its original water-soluble state in soil. The evolution of Cr(VI) species and the content of specific Cr species in soil are mainly determined by the contents of iron, exchangeable calcium ions and metal oxide hydrates, which effect the Cr(VI) reduction, precipitation and adsorption, respectively.
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Affiliation(s)
- Jing Yang
- College of Resources and Environment, Southwest University, Chongqing 400715, PR China
| | - Qian Guo
- College of Resources and Environment, Southwest University, Chongqing 400715, PR China
| | - Lei Li
- College of Resources and Environment, Southwest University, Chongqing 400715, PR China.
| | - Ruixue Wang
- College of Resources and Environment, Southwest University, Chongqing 400715, PR China
| | - Yucheng Chen
- College of Resources and Environment, Southwest University, Chongqing 400715, PR China; Chongqing Engineering Research Center of Rural Cleaning, Chongqing 400716, PR China
| | - Xingrun Wang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China
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7
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Xu Y, Fan Z, Huang Q, Lou Z, Xu X, Xu Y, Shen Y. Cr Migration Potential and Species Properties in the Soil Profile from a Chromate Production Site in the Groundwater Depression Cone Area. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2022; 109:600-608. [PMID: 35113218 DOI: 10.1007/s00128-022-03469-8] [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: 11/06/2021] [Accepted: 01/21/2022] [Indexed: 06/14/2023]
Abstract
The relationship between the migration process and speciation distribution of Cr is important for the risk assessment in the underground environment. In this work, soil columns were collected from the chromate production site, with a 40-year operation, in the groundwater depression cone area of North China plain. The relationship between chromium pollution features and the geochemical properties of soil was established, and the migration risk of Cr(VI) was assessed based on the Nemerow composite index and Hydrus-1D model. The maximum total Cr concentration in the chromium slag dumping site reached 907 mg/kg, and that in the chromate production workshop was more than 200 mg/kg across the depth. The migration of Cr might be accelerated in the soil with abundant Mn (236-1461 mg/kg) but scarce organic matters (< 0.45%). The Hydrus simulation indicated that Cr(VI) would reach a cumulative flux of 300-729 mg/cm2 after 50 years.
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Affiliation(s)
- Yukang Xu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Zikai Fan
- College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai, 200090, China
| | - Qiujie Huang
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Ziyang Lou
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.
| | - Xiaoyun Xu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yang Xu
- Shanghai Engineering Research Center of Solid Waste Treatment and Resource Recovery, Shanghai, 200240, China
| | - Yilong Shen
- Shanghai Engineering Research Center of Solid Waste Treatment and Resource Recovery, Shanghai, 200240, China
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8
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Kumar M, Bolan N, Jasemizad T, Padhye LP, Sridharan S, Singh L, Bolan S, O'Connor J, Zhao H, Shaheen SM, Song H, Siddique KHM, Wang H, Kirkham MB, Rinklebe J. Mobilization of contaminants: Potential for soil remediation and unintended consequences. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 839:156373. [PMID: 35649457 DOI: 10.1016/j.scitotenv.2022.156373] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 05/26/2022] [Accepted: 05/27/2022] [Indexed: 06/15/2023]
Abstract
Land treatment has become an essential waste management practice. Therefore, soil becomes a major source of contaminants including organic chemicals and potentially toxic elements (PTEs) which enter the food chain, primarily through leaching to potable water sources, plant uptake, and animal transfer. A range of soil amendments are used to manage the mobility of contaminants and subsequently their bioavailability. Various soil amendments, like desorbing agents, surfactants, and chelating agents, have been applied to increase contaminant mobility and bioavailability. These mobilizing agents are applied to increase the contaminant removal though phytoremediation, bioremediation, and soil washing. However, possible leaching of the mobilized pollutants during soil washing is a major limitation, particularly when there is no active plant uptake. This leads to groundwater contamination and toxicity to plants and soil biota. In this context, the present review provides an overview on various soil amendments used to enhance the bioavailability and mobility of organic and inorganic contaminants, thereby facilitating increased risk when soil is remediated in polluted areas. The unintended consequences of the mobilization methods, when used to remediate polluted sites, are discussed in relation to the leaching of mobilized contaminants when active plant growth is absent. The toxicity of targeted and non-targeted contaminants to microbial communities and higher plants is also discussed. Finally, this review work summarizes the existing research gaps in various contaminant mobilization approaches, and prospects for future research.
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Affiliation(s)
- Manish Kumar
- CSIR-National Environmental Engineering Research Institute, Nagpur 440020, Maharashtra, India
| | - Nanthi Bolan
- UWA School of Agriculture and Environment, The University of Western Australia, Perth, WA 6001, Australia; The UWA Institute of Agriculture, The University of Western Australia, Perth, WA 6001, Australia.
| | - Tahereh Jasemizad
- Department of Civil and Environmental Engineering, Faculty of Engineering, The University of Auckland, Auckland 1010, New Zealand
| | - Lokesh P Padhye
- Department of Civil and Environmental Engineering, Faculty of Engineering, The University of Auckland, Auckland 1010, New Zealand
| | - Srinidhi Sridharan
- CSIR-National Environmental Engineering Research Institute, Nagpur 440020, Maharashtra, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, Uttar Pradesh, India
| | - Lal Singh
- CSIR-National Environmental Engineering Research Institute, Nagpur 440020, Maharashtra, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, Uttar Pradesh, India
| | - Shiv Bolan
- Department of Civil and Environmental Engineering, Faculty of Engineering, The University of Auckland, Auckland 1010, New Zealand
| | - James O'Connor
- UWA School of Agriculture and Environment, The University of Western Australia, Perth, WA 6001, Australia; The UWA Institute of Agriculture, The University of Western Australia, Perth, WA 6001, Australia
| | - Haochen Zhao
- UWA School of Agriculture and Environment, The University of Western Australia, Perth, WA 6001, Australia
| | - Sabry M Shaheen
- University of Wuppertal, School of Architecture and Civil Engineering, Institute of Foundation Engineering, Water and Waste Management, Laboratory of Soil and Groundwater Management, Pauluskirchstraße 7, 42285 Wuppertal, Germany; King Abdulaziz University, Faculty of Meteorology, Environment, and Arid Land Agriculture, Department of Arid Land Agriculture, 21589 Jeddah, Saudi Arabia
| | - Hocheol Song
- Department of Environment, Energy and Geoinformatics, Sejong University, 98 Gunja-Dong, Guangjin-Gu, Seoul, Republic of Korea
| | - Kadambot H M Siddique
- The UWA Institute of Agriculture, The University of Western Australia, Perth, WA 6001, Australia
| | - Hailong Wang
- Biochar Engineering Technology Research Center of Guangdong Province, School of Environmental and Chemical Engineering, Foshan University, Foshan, Guangdong 528000, China; Key Laboratory of Soil Contamination Bioremediation of Zhejiang Province, Zhejiang A&F University, Hangzhou 311300, China
| | - M B Kirkham
- Department of Agronomy, Kansas State University, Manhattan, KS 66506, United States
| | - Jörg Rinklebe
- University of Wuppertal, School of Architecture and Civil Engineering, Institute of Foundation Engineering, Water and Waste Management, Laboratory of Soil and Groundwater Management, Pauluskirchstraße 7, 42285 Wuppertal, Germany; Department of Environment, Energy and Geoinformatics, Sejong University, 98 Gunja-Dong, Guangjin-Gu, Seoul, Republic of Korea; International Research Centre of Nanotechnology for Himalayan Sustainability (IRCNHS), Shoolini University, Solan 173212, Himachal Pradesh, India.
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9
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Chromium removal from tannery wastewaters with a strong cation exchange resin and species analysis of chromium by MINEQL+ . Sci Rep 2022; 12:9618. [PMID: 35688864 PMCID: PMC9187660 DOI: 10.1038/s41598-022-14423-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Accepted: 06/07/2022] [Indexed: 12/03/2022] Open
Abstract
Chromium (III) salts are highly applied for tanning purpose in tannery industries. The purpose of this study was removal and recovery of chromium(III) from tannery wastewater with a strong cation exchange resin. For this purpose, Amberlite 252 ZU was chosen as a strong cation exchange resin. In the first part of this study, The MINEQL+ computer program was applied depending on the optimum concentration and pH for determining Cr species in aqueous solutions. The second part of the work consists of measuring the exchange equilibrium of H+ ions and Cr(III) ions. Therefore, solutions containing fixed amounts of chromium were brought into contact with different amounts of resins. The evaluation of the obtained equilibrium parameters was done by surface complexing theory. Retention and regeneration steps were successfully performed in the column without any significant change up to 10 cycles. Efficiency was between 90 and 98% in removal studies, and between 81 and 92% in recovery studies. The results showed that a strong cation exchange resin Amberlite 252 ZU can be successfully used for chromium removal and recovery.
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10
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Huang Q, Hu X, Yuan X, Xiao T, Zhang M, Zhang D, Ren S, Luo W. Immobilization of W(VI) and/or Cr(VI) in soil treated with montmorillonite modified by a gemini surfactant and tetrachloroferrate (FeCl 4-). JOURNAL OF HAZARDOUS MATERIALS 2022; 425:127768. [PMID: 34810006 DOI: 10.1016/j.jhazmat.2021.127768] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Revised: 10/25/2021] [Accepted: 11/09/2021] [Indexed: 06/13/2023]
Abstract
The coexistence of highly toxic chromium (Cr) and the emerging contaminant tungsten (W) in the soil adjacent to W mining areas is identified. Immobilization of W and/or Cr is vital for the safe utilization of contaminated soil. In this study, the cationic gemini surfactant (butane-1,4-bis(dodecyl dimethyl ammonium bromide)) and tetrachloroferrate (FeCl4-)-modified montmorillonite (FeOMt) was applied to investigate the retention performance of W and/or Cr in the soil. Regardless of the initially spiked amount of WO42- and/or CrO42-, the W and/or Cr leached in soil solution was rapidly immobilized within 5 min. The immobilization rates of W and/or Cr in the single and binary soil systems were stably maintained against the variations in pH and coexisting anion. FeOMt showed more favorable performance in the retention of W and/or Cr with respect to the precursors (i.e., the original Mt and surfactant-modified Mt) and efficiently inhibited the phytotoxicity and bioaccumulation of W and/or Cr in mung beans. Due to the ion exchange, complexation, reduction, and flocculation, the addition of FeOMt transformed W and/or Cr from exchangeable/carbonate species to reducible/oxidizable fractions, reducing the environmental risk. FeCl4- complex, as a byproduct of the steel pickling process in industry, plays the pivotal role in the efficient retention of W and Cr. Based on the facile synthesis procedure and the efficient performance, the use of FeOMt for the amendment of W- and/or Cr-contaminated soil is feasible and promising.
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Affiliation(s)
- Qidong Huang
- Jiangxi Key Laboratory of Mining & Metallurgy Environmental Pollution Control, Jiangxi University of Science and Technology, Ganzhou 341000, PR China; School of Resources and Environmental Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, PR China
| | - Xiaojie Hu
- Jiangxi Key Laboratory of Mining & Metallurgy Environmental Pollution Control, Jiangxi University of Science and Technology, Ganzhou 341000, PR China; School of Resources and Environmental Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, PR China
| | - Xiujuan Yuan
- Jiangxi Key Laboratory of Mining & Metallurgy Environmental Pollution Control, Jiangxi University of Science and Technology, Ganzhou 341000, PR China; School of Resources and Environmental Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, PR China
| | - Ting Xiao
- Jiangxi Key Laboratory of Mining & Metallurgy Environmental Pollution Control, Jiangxi University of Science and Technology, Ganzhou 341000, PR China; School of Resources and Environmental Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, PR China
| | - Meng Zhang
- Jiangxi Academy of Environmental Sciences, Nanchang 330039, PR China
| | - Dachao Zhang
- Jiangxi Key Laboratory of Mining & Metallurgy Environmental Pollution Control, Jiangxi University of Science and Technology, Ganzhou 341000, PR China; School of Resources and Environmental Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, PR China; Ganzhou Technology Innovation Center for Mine Ecology Remediation, Ganzhou 341000, PR China
| | - Sili Ren
- Jiangxi Key Laboratory of Mining & Metallurgy Environmental Pollution Control, Jiangxi University of Science and Technology, Ganzhou 341000, PR China; School of Resources and Environmental Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, PR China
| | - Wuhui Luo
- Jiangxi Key Laboratory of Mining & Metallurgy Environmental Pollution Control, Jiangxi University of Science and Technology, Ganzhou 341000, PR China; School of Resources and Environmental Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, PR China; Jiangxi Academy of Environmental Sciences, Nanchang 330039, PR China.
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11
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Xu Z, Yu Y, Xu X, Tsang DCW, Yao C, Fan J, Zhao L, Qiu H, Cao X. Direct and Indirect Electron Transfer Routes of Chromium(VI) Reduction with Different Crystalline Ferric Oxyhydroxides in the Presence of Pyrogenic Carbon. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:1724-1735. [PMID: 34978795 DOI: 10.1021/acs.est.1c06642] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Electron transfer mediated by iron minerals is considered as a critical redox step for the dynamics of pollutants in soil. Herein, we explored the reduction process of Cr(VI) with different crystalline ferric oxyhydroxides in the presence of pyrogenic carbon (biochar). Both low- and high-crystallinity ferric oxyhydroxides induced Cr(VI) immobilization mainly via the sorption process, with a limited reduction process. However, the Cr(VI) reduction immobilization was inspired by the copresence of biochar. Low-crystallinity ferric oxyhydroxide had an intense chemical combination with biochar and strong sorption for Cr(VI) via inner-sphere complexation, leading to the indirect electron transfer route for Cr(VI) reduction, that is, the electron first transferred from biochar to iron mineral through C-O-Fe binding and then to Cr(VI) with Fe(III)/Fe(II) transformation on ferric oxyhydroxides. With increasing crystallinity of ferric oxyhydroxides, the direct electron transfer between biochar and Cr(VI) became the main electron transfer avenue for Cr(VI) reduction. The indirect electron transfer was suppressed in the high-crystallinity ferric oxyhydroxides due to less sorption of Cr(VI), limited combination with biochar, and higher iron stability. This study demonstrates that electron transfer mechanisms involving iron minerals change with the mineral crystallization process, which would affect the geochemical process of contaminants with pyrogenic carbon.
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Affiliation(s)
- Zibo Xu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon 852, Hong Kong, 999077, China
| | - Yulu Yu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xiaoyun Xu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Daniel C W Tsang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon 852, Hong Kong, 999077, China
| | - Chengbo Yao
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027, United States
| | - Jin Fan
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Ling Zhao
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hao Qiu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xinde Cao
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
- Shanghai Engineering Research Center for Solid Waste Treatment and Resource Recovery, Shanghai 200240, China
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12
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Zhu C, Wang Q, Huang X, Li T, Yang G. Microscopic understanding about adsorption and transport of different Cr(VI) species at mineral interfaces. JOURNAL OF HAZARDOUS MATERIALS 2021; 414:125485. [PMID: 33677319 DOI: 10.1016/j.jhazmat.2021.125485] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 02/10/2021] [Accepted: 02/19/2021] [Indexed: 06/12/2023]
Abstract
Cr(VI) ranks as one of the most toxic heavy metals and herein, microscopic mechanisms for adsorption and transport of different Cr(VI) oxyanions (Cr2O72- and CrO42-) at kaolinite interfaces are addressed by dispersion-corrected periodic density functional theory calculations. Cr(VI) oxyanions adsorb favorably at both tetrahedral and octahedral surfaces, and K+ ions serve as bridge for Cr(VI) oxyanions and tetrahedral surfaces while Cr(VI) oxyanions serve as bridge for K+ ions and octahedral surfaces. Adsorption structures are altered significantly by pH variation, and stability trends at different pH ranges are deciphered by the dominant interaction force with clay surfaces: Electrostatic interaction with K+ ions at tetrahedral surfaces whereas combined action of electrostatic and H-bonding interactions with Cr(VI) oxyanions at octahedral surfaces. Electron transfers are strongly pH-dependent, and clay surfaces serve as electron reservoirs. CrO42- rather than Cr2O72- is dominant at clay interfaces, and HCrO4- can co-exist under acidic conditions. Cr2O72- transformation to CrO42- is kinetically blocked at pH ≈ PZC while preferred at pH < PZC. Cr(VI) removal and reclamation should proceed at pH > 7.0 and pH < PZC, respectively. Results greatly promote the understanding about Cr(VI) bioavailability and fate in surficial environments and are also useful for Cr(VI) removal and reclamation.
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Affiliation(s)
- Chang Zhu
- College of Resources and Environments & Chongqing Key Laboratory of Soil Multi-scale Interfacial Process, Southwest University, Chongqing 400715, China
| | - Qian Wang
- College of Resources and Environments & Chongqing Key Laboratory of Soil Multi-scale Interfacial Process, Southwest University, Chongqing 400715, China
| | - Xiaoxiao Huang
- College of Resources and Environments & Chongqing Key Laboratory of Soil Multi-scale Interfacial Process, Southwest University, Chongqing 400715, China
| | - Tingting Li
- College of Resources and Environments & Chongqing Key Laboratory of Soil Multi-scale Interfacial Process, Southwest University, Chongqing 400715, China
| | - Gang Yang
- College of Resources and Environments & Chongqing Key Laboratory of Soil Multi-scale Interfacial Process, Southwest University, Chongqing 400715, China.
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13
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Zhu C, Huang X, Li T, Wang Q, Yang G. Mechanisms for Cr(VI) reduction by alcohols over clay edges: Reactive differences between ethanol and ethanediol, and selective conversions to Cr(IV), Cr(III) and Cr(II) species. J Colloid Interface Sci 2021; 603:37-47. [PMID: 34186408 DOI: 10.1016/j.jcis.2021.06.123] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 06/19/2021] [Accepted: 06/21/2021] [Indexed: 11/30/2022]
Abstract
Catalytic reduction by alcohols over clay minerals works efficiently under a wide range of pH and represents an emerging approach to control Cr(VI) contamination. Herein, mechanisms for Cr(VI) adsorption and reduction at clay edges are addressed by dispersion-corrected periodic DFT calculations, considering different active sites, and types (monohydric and polyhydric) and coverage of alcohols. Cr(VI) adsorbs favorably at clay edges, forming direct bonds and strong H-bonds. Mechanisms for Cr(VI) reduction by alcohols are largely determined by π-conjugation development, and efficient conversion conduces to Cr(VI) removal. Cr(II), Cr(III) and Cr(IV) are useful for different purposes, and high selectivity towards these products is realized through rational catalysts design: 1) Cr(IV) dominates at Al3+ site with all ethanol coverage, Al3+ site with high-coverage ethanediol, and Mg2+ site with low-coverage ethanol; 2) Cr(III) dominates at Al3+ and Mg2+ sites with low-coverage ethanediol; 3) Cr(II) dominates at Mg2+ site with high-coverage ethanol or ethanediol. Results agree finely with experimental observations available, and significant new insights have been provided for Cr management and recycling. Detailed electronic structure and vibrational analyses, which can also guide future experimental studies, manifest that Cr(VI) reduction progresses are effectively monitored by ESR and FT-IR techniques.
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Affiliation(s)
- Chang Zhu
- College of Resources and Environments & Chongqing Key Laboratory of Soil Multi-scale Interfacial Process, Southwest University, Chongqing 400715, China
| | - Xiaoxiao Huang
- College of Resources and Environments & Chongqing Key Laboratory of Soil Multi-scale Interfacial Process, Southwest University, Chongqing 400715, China
| | - Tingting Li
- College of Resources and Environments & Chongqing Key Laboratory of Soil Multi-scale Interfacial Process, Southwest University, Chongqing 400715, China
| | - Qian Wang
- College of Resources and Environments & Chongqing Key Laboratory of Soil Multi-scale Interfacial Process, Southwest University, Chongqing 400715, China
| | - Gang Yang
- College of Resources and Environments & Chongqing Key Laboratory of Soil Multi-scale Interfacial Process, Southwest University, Chongqing 400715, China.
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14
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Wang H, Zhang J, Zhu J, Chang J, Wang N, Chen H. Synergistic/antagonistic effects and mechanisms of Cr(VI) adsorption and reduction by Fe(III)-HA coprecipitates. JOURNAL OF HAZARDOUS MATERIALS 2021; 409:124529. [PMID: 33218908 DOI: 10.1016/j.jhazmat.2020.124529] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 10/29/2020] [Accepted: 11/06/2020] [Indexed: 06/11/2023]
Abstract
Widespread Fe(III)-humic acid (HA) coprecipitates (FHCs) have substantial impacts on the adsorption and reduction of Cr(VI) in soils and sediments, but whether this process is equal to the sum of their individual components remains unknown. In this study, ferrihydrite (Fh)- and HA-like FHCs (C/Fe<3 and C/Fe>3, respectively) were synthesized by controlling the initial C/Fe ratios (0.5-18) to explore the potential synergistic/antagonistic effects during the adsorption and reduction of Cr(VI). According to the results, antagonistic effects on Cr(VI) adsorption (5%-80%) were observed on Fh- and HA-like FHCs, where the antagonistic intensity increased with increasing HA proportions, respectively caused by the more serious occupation of adsorption sites and the stronger electrostatic repulsion to Cr(VI). Notably, significant synergistic reduction effects (5%-650%) occurred on Fh-like FHCs were found to be achieved by the activation of low-molecular HA (0.1-0.3 kDa) with primary/secondary hydroxylic groups, which might be induced by the inductive effect of Fh on complexed HA molecules according to density-functional theory (DFT) calculation. While slight antagonistic reduction effects (2%-45%) by HA-like FHCs were attributed to the decreasing accessibility of Cr(VI) to reductive phenolic groups, which might be blocked within FHC particles or complexed with Fe(III) ions through cation bridges.
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Affiliation(s)
- Hui Wang
- Beijing Key Laboratory of Water Resources & Environmental Engineering, China University of Geosciences, Beijing 100083, PR China
| | - Jia Zhang
- Beijing Key Laboratory of Water Resources & Environmental Engineering, China University of Geosciences, Beijing 100083, PR China.
| | - Jinqi Zhu
- Beijing Key Laboratory of Water Resources & Environmental Engineering, China University of Geosciences, Beijing 100083, PR China
| | - Jingjie Chang
- Beijing Key Laboratory of Water Resources & Environmental Engineering, China University of Geosciences, Beijing 100083, PR China
| | - Ning Wang
- Chinese Academy for Environmental Planning, Beijing 100020, PR China
| | - Honghan Chen
- Beijing Key Laboratory of Water Resources & Environmental Engineering, China University of Geosciences, Beijing 100083, PR China
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15
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Sun G, Fu F, Yu G, Yu P, Tang B. Migration behavior of Cr(VI) during the transformation of ferrihydrite-Cr(VI) co-precipitates: The interaction between surfactants and co-precipitates. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 767:145429. [PMID: 33550060 DOI: 10.1016/j.scitotenv.2021.145429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 01/04/2021] [Accepted: 01/22/2021] [Indexed: 06/12/2023]
Abstract
Redistribution of Cr(VI) in ferrihydrite-Cr(VI) co-precipitates (Fh-Cr) was affected by co-precipitates transformation and coexisting substances. These effects were crucial for predicting the migration path of Cr(VI) in ferrihydrite-Cr(VI) co-precipitates. This work investigated the effects of the extensively used surfactants of anionic surfactant sodium dodecylbenzene sulfonate (SDBS) and cationic surfactant cetyltrimethylammonium bromide (CTAB) on the Fh-Cr transformation and redistribution of Cr(VI) for 10 days at different pH values (5.0, 7.5 and 9.0) and concentration of surfactants (0.5, 2.0 and 5.0 mM). The results showed that SDBS hindered the transformation of Fh-Cr to hematite and tended to transform into goethite. SDBS inhibited hematite formation by inhibiting the aggregation of Fh-Cr particles, and it enhanced the dissolution of Fh-Cr to facilitate the formation of goethite. Affected by the inhibition of Fh-Cr transformation, the process of Cr(VI) redistribution was delayed. CTAB did not affect the transformation of Fh-Cr, but allowed more Cr(VI) to enter the interior of iron minerals. When the surfactants were adsorbed on the Fh-Cr, SDBS decreased the adsorption of Cr(VI) by Fh-Cr, while CTAB increased the Cr(VI) adsorption. The findings of this study contribute to understand the effects of surfactants on the transformation of Fh-Cr and the behaviors of Cr(VI) during this process.
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Affiliation(s)
- Guangzhao Sun
- School of Environmental Science and Engineering, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong University of Technology, Guangzhou 510006, China
| | - Fenglian Fu
- School of Environmental Science and Engineering, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong University of Technology, Guangzhou 510006, China.
| | - Guangda Yu
- School of Environmental Science and Engineering, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong University of Technology, Guangzhou 510006, China
| | - Peijing Yu
- School of Environmental Science and Engineering, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong University of Technology, Guangzhou 510006, China
| | - Bing Tang
- School of Environmental Science and Engineering, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong University of Technology, Guangzhou 510006, China
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16
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Yu P, Fu F, Sun G, Tang B. Effects of oxalate and citrate on the behavior and redistribution of Cr(VI) during ferrihydrite-Cr(VI) co-precipitates transformation. CHEMOSPHERE 2021; 266:128977. [PMID: 33246706 DOI: 10.1016/j.chemosphere.2020.128977] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 11/08/2020] [Accepted: 11/13/2020] [Indexed: 06/11/2023]
Abstract
Understanding the influence of organic matters on the fate of Cr(VI) during ferrihydrite-Cr(VI) (Fh-Cr) co-precipitates transformation helps to study the retention of Cr(VI) by iron oxides in the environment. In this paper, Fh-Cr was prepared by co-precipitation and the redistribution of Cr(VI) in the oxalate or citrate system during the transformation of Fh-Cr was studied. X-ray diffraction, Fourier transform infrared spectroscopy, Transmission electron microscopy, and X-ray photoelectron spectroscopy were used to characterize Fh-Cr for aging 7 days at 70 °C. Results showed that both oxalate and citrate could hinder the release of Cr(VI) from Fh-Cr and abate the harm of Cr(VI). Oxalate improved the transformation from Fh-Cr to hematite and promoted Cr(VI) to be enfolded into the secondary minerals to further immobilize Cr at initial pH of 5.0 and 7.0, while citrate evidently reduced the release of Cr(VI) through stabilizing Fh-Cr at initial pH of 9.0. Besides, reduction of Cr(VI) by oxalate and citrate was through forming the surface complexes that promoted electron transfer from oxalate or citrate to Cr(VI), which can effectively abate the harm of Cr(VI). The findings of this study can promote understanding of the influences of organic matters on Cr(VI) immobilization during transformation of iron oxides in nature.
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Affiliation(s)
- Peijing Yu
- School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, China
| | - Fenglian Fu
- School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, China.
| | - Guangzhao Sun
- School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, China
| | - Bing Tang
- School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, China
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17
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Hua H, Zhao Z, Xu R, Chang E, Fang D, Dong Y, Hong Z, Shi R, Jiang J. Effect of ferrolysis and organic matter accumulation on chromate adsorption characteristics of an Oxisol-derived paddy soil. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 744:140868. [PMID: 32717467 DOI: 10.1016/j.scitotenv.2020.140868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 06/14/2020] [Accepted: 07/08/2020] [Indexed: 06/11/2023]
Abstract
How paddy cultivation influences the adsorption isotherms, envelopes, and the kinetics of hexavalent chromate (Cr(VI)) on Fe (hydro)oxide-rich paddy soil, as well as the mechanisms involved, remain largely unaddressed. To this end, the Cr(VI) adsorption characteristics on a paddy soil, in comparison with its parent upland Oxisol, were studied. The results showed that Cr(VI) adsorption capacities (Qmad) were higher in the surface Oxisol than in the same layer of paddy soil. The Qmad increased by 18.0% and 41.3% after removal of soil organic matter (SOM) from the surface Oxisol and paddy soil layers, respectively, indicating that Cr(VI) adsorption was considerably inhibited by SOM. The adsorption and desorption isotherms demonstrated that non-electrostatic adsorption was mainly responsible for Cr(VI) adsorption, accounting for 59.37%-83.42% of Cr(VI) adsorption capacities. The negative shift of the zeta potential-pH curves with Cr(VI) loading further corroborated the finding that non-electrostatic adsorption is largely responsible for Cr(VI) retention. Cr(VI) adsorption at equilibrium, obtained by the stirred flow chamber technique, and the free Fe (hydro)oxides (Fed) contents were in the same order, suggesting that Fed are the main adsorbents for Cr(VI). Therefore, paddy cultivation has had a profound impact on the electrochemical properties of the Oxisol and on subsequent Cr(VI) adsorption characteristics.
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Affiliation(s)
- Hui Hua
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, P. O. Box, 821, Nanjing, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhenjie Zhao
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, P. O. Box, 821, Nanjing, China
| | - Renkou Xu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, P. O. Box, 821, Nanjing, China
| | - E Chang
- Institute of Information Science and Technology, Southeast University, Nanjing 210096, China
| | - Di Fang
- College of Resources and Environmental Sciences, Nanjing Agriculture University, Nanjing, 210095, China
| | - Ying Dong
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, P. O. Box, 821, Nanjing, China
| | - Zhineng Hong
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, P. O. Box, 821, Nanjing, China
| | - Renyong Shi
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, P. O. Box, 821, Nanjing, China
| | - Jun Jiang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, P. O. Box, 821, Nanjing, China.
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18
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Wang X, Li L, Yan X, Meng X, Chen Y. Processes of chromium (VI) migration and transformation in chromate production site: A case study from the middle of China. CHEMOSPHERE 2020; 257:127282. [PMID: 32531491 DOI: 10.1016/j.chemosphere.2020.127282] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 04/25/2020] [Accepted: 05/30/2020] [Indexed: 06/11/2023]
Abstract
The migration and redox transformation processes of toxic Cr(VI) in the upper and deep soil of chromate-polluted site are of great importance for the environmental risk control and soil remediation. In this study, soils from surface to deep (around 30-60 m) and the groundwater in a typical abandoned chromate production plant site which has experienced decades of contamination were both sampled and analyzed. The results show that the soil in the leaching workshop of Cr(VI), dichromate transformation workshop and chromium slag dumping ground exhibits severe contamination of chromium and the pollution has extended to the groundwater, causing serious pollution in groundwater too. The vertical migration and transformation of Cr(VI) in the soil layer are mainly affected by the soil permeability, organic matter content and the amount of water passing through the soil layer. During the downward migration, Cr(VI) tends to be retained by the clay layer and further accumulates around the depth of 5-10 m where the concentrations of both hexavalent and total Cr reach maximum values, and then continues to diffuse from the accumulation layer towards the deeper soil. Accompanying with the reduction of Cr(VI) by organic matter in the soil, the Cr(III) exists at various depths. When the depth is below the groundwater level of saturated aquifer, the distribution of chromium in the soil and groundwater reaches leaching and redox equilibrium due to the long-term interaction between the soil and groundwater.
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Affiliation(s)
- Xingrun Wang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, PR China
| | - Lei Li
- College of Resources and Environment, Southwest University, Chongqing, 400715, PR China; Chongqing Engineering Research Center of Rural Cleaning, Chongqing, 400716, PR China.
| | - Xianghua Yan
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, PR China
| | - Xiaoguang Meng
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, PR China; Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ, 07030, United States
| | - Yucheng Chen
- College of Resources and Environment, Southwest University, Chongqing, 400715, PR China; Chongqing Engineering Research Center of Rural Cleaning, Chongqing, 400716, PR China
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19
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Yu G, Fu F, Ye C, Tang B. Behaviors and fate of adsorbed Cr(VI) during Fe(II)-induced transformation of ferrihydrite-humic acid co-precipitates. JOURNAL OF HAZARDOUS MATERIALS 2020; 392:122272. [PMID: 32086091 DOI: 10.1016/j.jhazmat.2020.122272] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 02/05/2020] [Accepted: 02/10/2020] [Indexed: 06/10/2023]
Abstract
The mobility of Cr(VI) in the environment is affected by the transformation of ferrihydrite (Fh) and ferrihydrite-humic acid co-precipitates (Fh-HA). However, the impacts of Fe(II)-induced transformation of Fh and Fh-HA on the mobility, speciation and partitioning of associated Cr(VI) remain unclear. In this study, the behaviors of adsorbed Cr(VI) during Fh and Fh-HA aging at 70 °C for 9 days (pH0 = 3.0 and 7.0) in the absence and presence of Fe(II) were studied. Results revealed that the main speciation of Cr(VI) after transformation was non-desorbable Cr and its formation involved the following pathways. Firstly, Fe(II) (0.2 and 2.0 mM) induced the transformation of Fh-HA to hematite and goethite, promoting the structural incorporation of adsorbed Cr into hematite and goethite via complexation. Secondly, under neutral condition (pH0 = 7.0), the low concentration of Fe(II) (0.2 mM) could not reduce completely Cr(VI) to Cr(III) and thus residual Cr(VI) was incorporated into the Cr(III)-Fe(III) co-precipitates. Thirdly, coprecipitated humic acid not only reduced Cr(VI) to Cr(III) via polysaccharide, but also formed complexes with incorporated Cr through carboxylic groups to sequester Cr. Our results demonstrate that Fe(II)-induced transformation of Fh-HA exerts major influences on associated Cr(VI) speciation and partitioning.
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Affiliation(s)
- Guangda Yu
- School of Environmental Science and Engineering, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong University of Technology, Guangzhou, 510006, China
| | - Fenglian Fu
- School of Environmental Science and Engineering, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong University of Technology, Guangzhou, 510006, China.
| | - Chujia Ye
- School of Environmental Science and Engineering, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong University of Technology, Guangzhou, 510006, China
| | - Bing Tang
- School of Environmental Science and Engineering, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Guangdong University of Technology, Guangzhou, 510006, China
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20
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Dzieniszewska A, Kyziol-Komosinska J, Pająk M. Adsorption and bonding strength of chromium species by ferrihydrite from acidic aqueous solutions. PeerJ 2020; 8:e9324. [PMID: 32566408 PMCID: PMC7293855 DOI: 10.7717/peerj.9324] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Accepted: 05/18/2020] [Indexed: 11/22/2022] Open
Abstract
The adsorption behavior of Cr(III) and Cr(VI) ions onto laboratory-synthesized 2-line ferrihydrite was investigated under a batch method as a function of initial chromium concentration (0.1-1000 mg L-1) and pH (3.0 and 5.0). Moreover, the effect of the type of anion (chloride and sulfate) on Cr(III) adsorption was studied. The affinity of Cr(III) ions for the ferrihydrite surface depended on both the type of anion and pH of the solution and the maximum adsorption capacities decreased as follows: q (SO4 2-, pH 5.0) > q (SO4 2-, pH 3.0) > q (Cl-, pH 5.0) > q (Cl-, pH 3.0), and were found to be 86.06 mg g-1, 83.59 mg g-1, 61.51 mg g-1 and 40.67 mg g-1, respectively. Cr(VI) ions were bound to ferrihydrite in higher amounts then Cr(III) ions and the maximum adsorption capacity increased as the pH of the solution decreased and was 53.14 mg g-1 at pH 5.0 and 83.73 mg g-1 at pH 3.0. The adsorption process of Cr species was pH dependent, and the ions were bound to the surface of ferrihydrite by surface complexation. The Sips isotherm was the best-fit model to the results obtained from among the four isotherm models used, i.e., Freundlich, Langmuir, Dubinin-Radushkevich and Sips, indicating different adsorption centers participate in Cr uptake. In order to assess the bonding strength of the adsorbed chromium ions the modified BCR procedure, dedicated to the samples with a high iron content, was used. The results of the sequential extraction showed that Cr(III) ions were bound mainly in the immobile residual fraction and Cr(VI) ions were bound in the reducible fraction. The presence of Fe (oxyhydr)oxides in soil and sediments increases their adsorption capacity for Cr, in particular for hexavalent Cr in an acid environment due to their properties (high pHPZC).
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Affiliation(s)
| | | | - Magdalena Pająk
- Institute of Environmental Engineering, Polish Academy of Sciences, Zabrze, Poland
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21
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Shi Z, Peng S, Lin X, Liang Y, Lee SZ, Allen HE. Predicting Cr(vi) adsorption on soils: the role of the competition of soil organic matter. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2020; 22:95-104. [PMID: 31897461 DOI: 10.1039/c9em00477g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Cr(vi) has posed a serious risk for the environment and human beings because of its pollution and toxicity. It is essential to understand the equilibrium behavior of Cr(vi) in soils. In this study, the adsorption of Cr(vi) on fourteen soils was studied with batch experiments and quantitative modeling. The batch experiments included the adsorption edge and adsorption isotherm experiments, investigating the adsorption of Cr(vi) with varying soil properties, solution pH, and initial Cr(vi) concentrations. The experimental data were then modeled using the surface complexation models in Visual MINTEQ of CD-MUSIC by considering the adsorption of Cr(vi) and ions onto Fe (hydr)oxides and Al (hydr)oxides, and the Stockholm Humic Model and the fixed charge site model by accounting for the adsorption of the cations to soil organic matter and clay, respectively. Particularly, the modeling method of this study introduced an important parameter RO- to account for the amount of soil organic matter irreversibly adsorbed on soil minerals. Overall, the model predicted reasonably well for the equilibrium partition of Cr(vi) under various conditions with a root-mean-square-error of 0.35 for the adsorption edge data and 0.19 for the adsorption isotherm data. According to the model calculations, ferrihydrite dominated the binding of Cr(vi) at pH of 3.0-7.0. The content of ferrihydrite and reactive soil organic matter was found to be the main factor influencing RO-. The modeling results help to understand and predict Cr(vi) adsorption on different soils and are beneficial to environmental risk assessment and pollution remediation.
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Affiliation(s)
- Zhenqing Shi
- School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, PR China.
| | - Shimeng Peng
- School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, PR China.
| | - Xiaofeng Lin
- School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, PR China.
| | - Yuzhen Liang
- School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong 510006, PR China.
| | - Suen-Zone Lee
- Chia Nan University of Pharmacy and Science, Tainan City 71710, Taiwan
| | - Herbert E Allen
- Department of Civil and Environmental Engineering, University of Delaware, Newark, DE 19716, USA
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22
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Islam MA, Angove MJ, Morton DW. Recent innovative research on chromium (VI) adsorption mechanism. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.enmm.2019.100267] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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23
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Veselská V, Šillerová H, Göttlicher J, Michálková Z, Siddique JA, Číhalová S, Chrastný V, Steininger R, Mangold S, Komárek M. The role of soil components in synthetic mixtures during the adsorption and speciation changes of Cr(VI): Conjunction of the modeling approach with spectroscopic and isotopic investigations. ENVIRONMENT INTERNATIONAL 2019; 127:848-857. [PMID: 31075676 DOI: 10.1016/j.envint.2019.03.066] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 02/26/2019] [Accepted: 03/27/2019] [Indexed: 06/09/2023]
Abstract
This study investigates redox transitions associated with the adsorption of Cr(VI) on commonly occurring soil components (silicates, oxides and humic acids) and their synthetic mixtures by coupling the mechanistic surface complexation modeling with spectroscopic and isotopic analyses. The mixtures of soil components were prepared to reflect the composition of the real anthroposol sample, determined by X-ray Powder Diffraction (XRD), total organic carbon (TOC) measurement and extraction methods. The effect of different initial Cr(VI) concentrations (2×10-2, 5×10-4, 10-4, 10-5, and 10-6M), background electrolyte (10-3, 10-2, and 10-1M KNO3), pH values (3-9), and sorbate/sorbent ratios (2g/L - 20g/L) were investigated. Maghemite and ferrihydrite were confirmed to be the main phases controlling Cr(VI) adsorption with increasing Cr(VI) concentration. Humic acids were primarily responsible for Cr(VI) reduction, especially at low pH values. The reduction of Cr(VI) was also proved in case of illite and kaolinite by XAS and isotopic analyses. Illite revealed higher reduction capacity in comparison with kaolinite based on XAS measurements. Chromium isotopic fractionation, resulting from Cr(VI) reduction, was the highest in the case of humic acids, followed by kaolinite and illite. However, a dissolution of intrinsic Cr originally present within kaolinite and illite might affect the final Cr isotopic composition of the supernatants due to its different Cr isotopic signature. In general, the combination of three different approaches was confirmed to offer more comprehensive information about Cr(VI) adsorption and/or reduction in soils. Detailed studies using soil mixtures can help to predict how the soil components affect Cr(VI) behavior in natural soils and possibly could improve the environmental remediation processes.
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Affiliation(s)
- Veronika Veselská
- Department of Environmental Geosciences, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, CZ-16500 Prague, Czech Republic.
| | - Hana Šillerová
- Department of Environmental Geosciences, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, CZ-16500 Prague, Czech Republic
| | - Jörg Göttlicher
- Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, DE-76344 Eggenstein-Leopoldshafen, Germany
| | - Zuzana Michálková
- Department of Environmental Geosciences, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, CZ-16500 Prague, Czech Republic
| | - Jamal A Siddique
- Department of Environmental Geosciences, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, CZ-16500 Prague, Czech Republic
| | - Sylva Číhalová
- Department of Environmental Geosciences, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, CZ-16500 Prague, Czech Republic
| | - Vladislav Chrastný
- Department of Environmental Geosciences, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, CZ-16500 Prague, Czech Republic
| | - Ralph Steininger
- Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, DE-76344 Eggenstein-Leopoldshafen, Germany
| | - Stefan Mangold
- Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, DE-76344 Eggenstein-Leopoldshafen, Germany
| | - Michael Komárek
- Department of Environmental Geosciences, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, CZ-16500 Prague, Czech Republic
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24
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Opportunities and constraints of using the innovative adsorbents for the removal of cobalt(II) from wastewater: A review. ACTA ACUST UNITED AC 2018. [DOI: 10.1016/j.enmm.2018.10.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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25
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Zhu L, Fu F, Tang B. Coexistence or aggression? Insight into the influence of phosphate on Cr(VI) adsorption onto aluminum-substituted ferrihydrite. CHEMOSPHERE 2018; 212:408-417. [PMID: 30149314 DOI: 10.1016/j.chemosphere.2018.08.085] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Revised: 08/15/2018] [Accepted: 08/17/2018] [Indexed: 06/08/2023]
Abstract
This work aims to explore how phosphate affected hexavalent chromium (Cr(VI)) removal and the interaction between the aluminum-substituted ferrihydrite (shortened as Fh-Al) and Cr(VI) in the presence of phosphate. The adsorption behaviors of Cr(VI) on Fh-Al were tested in a synthetic solution containing Cr(VI) and phosphate. Series of characterization techniques, such as X-ray diffraction analysis, transmission electron microscopy equipped with the energy dispersive X-ray spectroscopy, attenuated total reflection Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy, have been used to analyze the Fh-Al before and after the adsorption of Cr(VI) in the presence of phosphate. Desirable adsorption performances of Cr(VI) occurred at pH value 3.0. Cr(VI) showed low affinity to Fh-Al due to the negative influence of phosphate. Addition of phosphate forced Cr(VI) out of Fh-Al surfaces like an "invader". The adsorption process was better described by the Langmuir isotherm model, and the adsorption capacity of Cr(VI) in the presence of 9.3 mg/L phosphate was 42.09 mg/g. The mechanism for Cr(VI) removal by Fh-Al under the influence of phosphate was developed as follows: (1) electrostatic interaction, (2) the formation of FeOCr complexes, and (3) the formation of ternary complexes between Fh-Al and Cr(VI) using phosphate as medium.
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Affiliation(s)
- Lijun Zhu
- School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, China
| | - Fenglian Fu
- School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, China.
| | - Bing Tang
- School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, China
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26
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Mamun AA, Morita M, Matsuoka M, Tokoro C. Sorption mechanisms of chromate with coprecipitated ferrihydrite in aqueous solution. JOURNAL OF HAZARDOUS MATERIALS 2017; 334:142-149. [PMID: 28407541 DOI: 10.1016/j.jhazmat.2017.03.058] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2016] [Revised: 03/12/2017] [Accepted: 03/25/2017] [Indexed: 06/07/2023]
Abstract
Hexavalent chromium (Cr(VI)) attracted researchers' interest for its toxicity, natural availability and removal difficulty. Nevertheless, its sorption mechanism is not clearly understood yet. In this work, we elucidated the sorption mechanism of the co-precipitation of chromates with ferrihydrite through quantitative analysis. The influence of Cr/Fe molar ratio on sorption was investigated by zeta potential measurements, X-ray diffraction (XRD) and X-ray adsorption fine-structure analysis (XAFS). Coprecipitation at pH 5 showed almost twice the sorption density of adsorption at pH 5. In co-precipitation, a shift of the XRD peak due to inner-sphere sorption of chromate was observed at Cr/Fe molar ratio 0.5. For adsorption, the same peak shift was confirmed at Cr/Fe molar ratio of 1. Zeta potential at pH 5 suggested that the sorption mechanism changed at Cr/Fe molar ratio 0.25 for coprecipitation and at Cr/Fe molar ratio of 1 for adsorption. Fitting of Cr and Fe K-edge extended X-ray adsorption fine-structure suggested that ferrihydrite immobilized Cr(VI) via outer sphere surface complexation for lower Cr/Fe ratios and via inner-sphere surface complexation for higher molar ratios. At higher molar ratios, bidentate binuclear CrFe bonds were well established, thus resulting in the expansion of the ferrihydrite structure.
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Affiliation(s)
- Abdullah Al Mamun
- Graduate School of Creative Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.
| | - Masao Morita
- Graduate School of Creative Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.
| | - Mitsuaki Matsuoka
- Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.
| | - Chiharu Tokoro
- Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.
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27
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Hudcová B, Veselská V, Filip J, Číhalová S, Komárek M. Sorption mechanisms of arsenate on Mg-Fe layered double hydroxides: A combination of adsorption modeling and solid state analysis. CHEMOSPHERE 2017; 168:539-548. [PMID: 27839879 DOI: 10.1016/j.chemosphere.2016.11.031] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 10/27/2016] [Accepted: 11/05/2016] [Indexed: 06/06/2023]
Abstract
Layered double hydroxides have been proposed as effective sorbents for As(V), but studies investigating adsorption mechanisms usually lack a comprehensive mechanistic/modeling approach. In this work, we propose coupling surface complexation modeling with various spectroscopic techniques. To this end, a series of batch experiments at different pH values were performed. Kinetic data were well fitted by a pseudo-second order kinetic model, and the equilibrium data were fitted by the Freundlich model. Moreover, the pH-dependent As(V) sorption data were satisfactorily fitted by a diffuse layer model, which described the formation of >SOAsO3H- monodentate and >(SO)2AsO2- bidentate inner-sphere complexes (">S" represents a crystallographically-bound group on the surface). Additionally, XPS analyses confirmed the adsorption mechanisms. The sorption mechanisms were affected by anion exchange, which was responsible for the formation of outer sphere complexes, as identified by XRD and FTIR analyses. Furthermore, a homogenous distribution of As(V) was determined by HR-TEM with elemental mapping. Using low-temperature Mössbauer spectroscopy on isotope 57Fe, a slight shift of the hyperfine parameters towards higher values following As(V) sorption was measured, indicating a higher degree of structural disorder. In general, mechanistic adsorption modeling coupled with solid state analyses presents a powerful approach for investigating the adsorption mechanism of As(V) on Mg-Fe LDH or other sorbents.
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Affiliation(s)
- Barbora Hudcová
- Department of Environmental Geosciences, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, Prague 6 - Suchdol, 165 21, Czech Republic
| | - Veronika Veselská
- Department of Environmental Geosciences, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, Prague 6 - Suchdol, 165 21, Czech Republic
| | - Jan Filip
- Regional Centre of Advanced Technologies and Materials, Departments of Physical Chemistry and Experimental Physics, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71, Olomouc, Czech Republic
| | - Sylva Číhalová
- Department of Environmental Geosciences, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, Prague 6 - Suchdol, 165 21, Czech Republic
| | - Michael Komárek
- Department of Environmental Geosciences, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, Prague 6 - Suchdol, 165 21, Czech Republic.
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