Formation of Cd precipitates on γ-Al2O3: Implications for Cd sequestration in the environment
Apart from surface complexation, precipitation of minerals also plays an important role in reducing the mobility and transport of heavy metals in the environment. In this study, Cd(II) sorption species on surfaces of γ-Al2O3 at pH 7.5 were characterized using multiple techniques. Results show that i...
| Main Authors: | , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2019-05-01
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| Series: | Environment International |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0160412019300807 |
| _version_ | 1819142248079556608 |
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| author | Qian Sun Cun Liu Peixin Cui Tingting Fan Mengqiang Zhu Marcelo Eduardo Alves Matthew G. Siebecker Donald L. Sparks Tongliang Wu Wei Li Dongmei Zhou Yujun Wang |
| author_facet | Qian Sun Cun Liu Peixin Cui Tingting Fan Mengqiang Zhu Marcelo Eduardo Alves Matthew G. Siebecker Donald L. Sparks Tongliang Wu Wei Li Dongmei Zhou Yujun Wang |
| author_sort | Qian Sun |
| collection | DOAJ |
| description | Apart from surface complexation, precipitation of minerals also plays an important role in reducing the mobility and transport of heavy metals in the environment. In this study, Cd(II) sorption species on surfaces of γ-Al2O3 at pH 7.5 were characterized using multiple techniques. Results show that in addition to adsorption complexes, Cd hydroxide phases (Cd(OH)2 precipitates and Cdx(OH)y polynuclear complexes) were formed at the initial stages of Cd(II) sorption and gradually transformed to CdCO3 with time. In addition, Cd(II) formed CdAl layered double hydroxide (LDH) on γ-Al2O3 under various conditions, independent of temperature and Cd loadings. The formation of Cd hydroxide phases and CdAl LDH could be ascribed to surface-induced precipitation because the bulk solution was undersaturated with respect to hydroxides. CdAl LDH formation on the Al-bearing mineral here is rather surprising because typically this occurs with elements of ionic radii similar to that of Al3+; this formation is unknown for metals such as Cd(II) with a much larger ionic radius. The thermodynamic feasibility of CdAl LDH formation was further confirmed by laboratory synthesis of CdAl LDH and density function theory (DFT) calculations. These results suggest that Cd precipitation on Al-bearing minerals can be an important mechanism for Cd immobilization in the natural environment. Additionally, the finding of CdAl LDH formation on Al-bearing minerals and the thermodynamic stability of CdAl LDH provides new insights into the remediation of Cd-polluted soils and aquatic systems. Keywords: Cadmium, γ-Al2O3, Precipitation, Cd-Al layered double hydroxide, Cd hydroxide phases, CdCO3 |
| first_indexed | 2024-12-22T12:07:19Z |
| format | Article |
| id | doaj.art-4573acfe237449a79a8ce823d8981004 |
| institution | Directory Open Access Journal |
| issn | 0160-4120 |
| language | English |
| last_indexed | 2024-12-22T12:07:19Z |
| publishDate | 2019-05-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Environment International |
| spelling | doaj.art-4573acfe237449a79a8ce823d89810042022-12-21T18:26:23ZengElsevierEnvironment International0160-41202019-05-01126234241Formation of Cd precipitates on γ-Al2O3: Implications for Cd sequestration in the environmentQian Sun0Cun Liu1Peixin Cui2Tingting Fan3Mengqiang Zhu4Marcelo Eduardo Alves5Matthew G. Siebecker6Donald L. Sparks7Tongliang Wu8Wei Li9Dongmei Zhou10Yujun Wang11Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, The Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, ChinaKey Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, The Chinese Academy of Sciences, Nanjing 210008, ChinaKey Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, The Chinese Academy of Sciences, Nanjing 210008, ChinaNanjing Institute of Environmental Sciences, Ministry of Environmental Protection of the People's Republic of China, Nanjing 210008, ChinaDepartment of Ecosystem Science and Management, University of Wyoming, Laramie, Wyoming 82071, United StatesDepartament of Exact Sciences ‘Luiz de Queiroz’ Agricultural College – ESALQ/USP, Piracicaba, SP 13418-900, BrazilDelaware Environmental Institute, Interdisciplinary Science and Engineering Laboratory, University of Delaware, Newark, DE, United States; Department of Plant and Soil Science, Texas Tech University, Lubbock, TX 79409, United StatesDelaware Environmental Institute, Interdisciplinary Science and Engineering Laboratory, University of Delaware, Newark, DE, United StatesKey Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, The Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, ChinaKey Laboratory of Surficial Geochemistry, Ministry of Education, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210008, ChinaKey Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, The Chinese Academy of Sciences, Nanjing 210008, ChinaKey Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, The Chinese Academy of Sciences, Nanjing 210008, China; Corresponding author.Apart from surface complexation, precipitation of minerals also plays an important role in reducing the mobility and transport of heavy metals in the environment. In this study, Cd(II) sorption species on surfaces of γ-Al2O3 at pH 7.5 were characterized using multiple techniques. Results show that in addition to adsorption complexes, Cd hydroxide phases (Cd(OH)2 precipitates and Cdx(OH)y polynuclear complexes) were formed at the initial stages of Cd(II) sorption and gradually transformed to CdCO3 with time. In addition, Cd(II) formed CdAl layered double hydroxide (LDH) on γ-Al2O3 under various conditions, independent of temperature and Cd loadings. The formation of Cd hydroxide phases and CdAl LDH could be ascribed to surface-induced precipitation because the bulk solution was undersaturated with respect to hydroxides. CdAl LDH formation on the Al-bearing mineral here is rather surprising because typically this occurs with elements of ionic radii similar to that of Al3+; this formation is unknown for metals such as Cd(II) with a much larger ionic radius. The thermodynamic feasibility of CdAl LDH formation was further confirmed by laboratory synthesis of CdAl LDH and density function theory (DFT) calculations. These results suggest that Cd precipitation on Al-bearing minerals can be an important mechanism for Cd immobilization in the natural environment. Additionally, the finding of CdAl LDH formation on Al-bearing minerals and the thermodynamic stability of CdAl LDH provides new insights into the remediation of Cd-polluted soils and aquatic systems. Keywords: Cadmium, γ-Al2O3, Precipitation, Cd-Al layered double hydroxide, Cd hydroxide phases, CdCO3http://www.sciencedirect.com/science/article/pii/S0160412019300807 |
| spellingShingle | Qian Sun Cun Liu Peixin Cui Tingting Fan Mengqiang Zhu Marcelo Eduardo Alves Matthew G. Siebecker Donald L. Sparks Tongliang Wu Wei Li Dongmei Zhou Yujun Wang Formation of Cd precipitates on γ-Al2O3: Implications for Cd sequestration in the environment Environment International |
| title | Formation of Cd precipitates on γ-Al2O3: Implications for Cd sequestration in the environment |
| title_full | Formation of Cd precipitates on γ-Al2O3: Implications for Cd sequestration in the environment |
| title_fullStr | Formation of Cd precipitates on γ-Al2O3: Implications for Cd sequestration in the environment |
| title_full_unstemmed | Formation of Cd precipitates on γ-Al2O3: Implications for Cd sequestration in the environment |
| title_short | Formation of Cd precipitates on γ-Al2O3: Implications for Cd sequestration in the environment |
| title_sort | formation of cd precipitates on γ al2o3 implications for cd sequestration in the environment |
| url | http://www.sciencedirect.com/science/article/pii/S0160412019300807 |
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