חיפוש מתקדם
Badreddine, R., Unité de Science du Sol, INRA, Route de Saint Cyr, 78026 Versailles, France
Humez, A.-N., Unité de Science du Sol, INRA, Route de Saint Cyr, 78026 Versailles, France
Mingelgrin, U., Inst. of Soil, Water/Environ. Sci., Agricultural Research Organization, Volcani Center, P.O. Box 6, Bet-Dagan, 50250, Israel
Benchara, A., Ctr. Rech. Environ., Ener./Dechet, Limay, France
Meducin, F., Lab. Phys./Mecan. Milieux Heterogen., CNRS, Ecl. Sup. de Phys./de Chim. Indust., 10 rue Vauquelin, 75231 París Cedex 5, France
Prost, R., Unité de Science du Sol, INRA, Route de Saint Cyr, 78026 Versailles, France
Toxic elements found in wastes may have a negative impact on the environment, especially through the contamination of groundwater and plants. To reduce their mobility and availability, French regulations mandate the solidification and stabilization of toxic wastes. Many methods to stabilize and solidify wastes exist, among them the Ecofix process which employs low cost materials and consists of mixing wastes with lime, aluminum hydroxide, and silica. To evaluate the long-term behavior of solidified/ stabilized (S/S) samples, their alteration under saturated conditions was studied in a water extractor, a Soxhlet-like device, used to follow the weathering of rocks. Kinetic measurements have shown that the release of Fe, Pb, Cd, Cr, and Cu was very slow, indicating a strong retention of these elements by the S/S materials prepared by the Ecofix process. To elucidate the mechanisms of retention of the trace metals, the mineral phases that existed in the S/S samples throughout and at the end of the extraction runs were studied by X-ray diffraction and by infrared and nuclear magnetic resonance spectroscopies. Scanning electron microscopic (SEM) examinations and electron microprobe analyses of the S/S samples were also performed at different stages of weathering. These observations revealed that assorted calcium silicate hydrates (C-S-H) were the predominant phases in the S/S preparations and that gradual alterations occurred in the structure of the investigated materials. The overall Ca/Si ratio of the C-S-H phases decreased as the enhanced alteration progressed. Although trace metals in oxide, hydroxide, and carbonate forms were found in the S/S materials, the bulk of the trace metals was incorporated in the matrix of the C-S-H phases.
פותח על ידי קלירמאש פתרונות בע"מ -
הספר "אוצר וולקני"
אודות
תנאי שימוש
Retention of Trace Metals by Solidified/Stabilized Wastes: Assessment of Long-Term Metal Release
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Badreddine, R., Unité de Science du Sol, INRA, Route de Saint Cyr, 78026 Versailles, France
Humez, A.-N., Unité de Science du Sol, INRA, Route de Saint Cyr, 78026 Versailles, France
Mingelgrin, U., Inst. of Soil, Water/Environ. Sci., Agricultural Research Organization, Volcani Center, P.O. Box 6, Bet-Dagan, 50250, Israel
Benchara, A., Ctr. Rech. Environ., Ener./Dechet, Limay, France
Meducin, F., Lab. Phys./Mecan. Milieux Heterogen., CNRS, Ecl. Sup. de Phys./de Chim. Indust., 10 rue Vauquelin, 75231 París Cedex 5, France
Prost, R., Unité de Science du Sol, INRA, Route de Saint Cyr, 78026 Versailles, France
Retention of Trace Metals by Solidified/Stabilized Wastes: Assessment of Long-Term Metal Release
Toxic elements found in wastes may have a negative impact on the environment, especially through the contamination of groundwater and plants. To reduce their mobility and availability, French regulations mandate the solidification and stabilization of toxic wastes. Many methods to stabilize and solidify wastes exist, among them the Ecofix process which employs low cost materials and consists of mixing wastes with lime, aluminum hydroxide, and silica. To evaluate the long-term behavior of solidified/ stabilized (S/S) samples, their alteration under saturated conditions was studied in a water extractor, a Soxhlet-like device, used to follow the weathering of rocks. Kinetic measurements have shown that the release of Fe, Pb, Cd, Cr, and Cu was very slow, indicating a strong retention of these elements by the S/S materials prepared by the Ecofix process. To elucidate the mechanisms of retention of the trace metals, the mineral phases that existed in the S/S samples throughout and at the end of the extraction runs were studied by X-ray diffraction and by infrared and nuclear magnetic resonance spectroscopies. Scanning electron microscopic (SEM) examinations and electron microprobe analyses of the S/S samples were also performed at different stages of weathering. These observations revealed that assorted calcium silicate hydrates (C-S-H) were the predominant phases in the S/S preparations and that gradual alterations occurred in the structure of the investigated materials. The overall Ca/Si ratio of the C-S-H phases decreased as the enhanced alteration progressed. Although trace metals in oxide, hydroxide, and carbonate forms were found in the S/S materials, the bulk of the trace metals was incorporated in the matrix of the C-S-H phases.
Scientific Publication
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