The Experts below are selected from a list of 1053 Experts worldwide ranked by ideXlab platform
Qicheng Feng - One of the best experts on this subject based on the ideXlab platform.
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adsorption characteristics of cu2 species on Cerussite surfaces and implications for sulfidization flotation
Separation and Purification Technology, 2021Co-Authors: Qian Zhang, Qicheng Feng, Shuming Wen, Yongchao MiaoAbstract:Abstract Metal ions are unavoidable in pulp solution, and they frequently influence the flotation recovery of minerals, such as by activation or depression. In this work, we systematically investigated the adsorption characteristics of Cu2+ species on Cerussite surfaces and the concomitant effect on sulfidization flotation by micro-flotation experiments and surface analysis. The flotation results indicated that the flotation recovery of Cerussite was almost unchanged at low Cu2+ concentration in the presence of Na2S, but it decreased at high Cu2+ concentration. X-ray photoelectron spectroscopy indicated that CuCO3 species formed on Cerussite surface in the presence of Cu2+, and Pb–S species and Cu–S species formed after Cu2+–Na2S treatment. Time-of-flight-secondary-ion mass spectrometry indicated that the distribution of lead species narrowed and that of copper species broadened with increasing Cu2+ concentration, which demonstrated that Cu2+ covered the mineral surfaces and inherent Pb2+ was shield. Ultraviolet–visible spectroscopy indicated that the stability of Cerussite surface increased with increasing amount of added Na2S. Compared with only Na2S treatment, consumption of xanthate was almost unchanged at low Cu2+ concentration, whereas consumption of xanthate considerably increased at high Cu2+ concentration, which may be because xanthate was consumed by the residual copper ions in the pulp solution. Zeta potential measurements indicated that Cu2+ can chemisorb on Cerussite surfaces and increasing the Cu2+ concentration facilitates adsorption of copper species, but it inhibits adsorption of Na2S and BX. Therefore, sulfidization flotation of Cerussite is not substantially affected by low concentrations of Cu2+, but is greatly affected by high concentrations of Cu2+.
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combined dft and xps investigation of enhanced adsorption of sulfide species onto Cerussite by surface modification with chloride
Applied Surface Science, 2017Co-Authors: Qicheng Feng, Shuming Wen, Jiushuai Deng, Wenjuan ZhaoAbstract:Abstract This study systematically investigates the enhanced adsorption of sulfide species onto Cerussite by surface modification with chloride through density functional theory calculations and X-ray photoelectron spectroscopy (XPS) measurements. Calculation results demonstrate obvious differences in the surface structures and electronic properties of Cerussite after HS− adsorption in the absence and presence of chloride species. Surface modification with chloride promotes the stable adsorption of HS− onto the Cerussite surface, and the hybridization of Pb 6p orbital at the surface layer and S 3p orbital from HS− is enhanced. Moreover, the reactivity of Cerussite surfaces is enhanced by the occurrence of new DOS peaks of Pb 6p and S 3p near the Fermi level and by the transfer of additional electrons between the bonding atoms in the presence of chloride. Meanwhile, Mulliken population and XPS analysis results indicate that a slight oxidation is involved in the interaction between sulfide species and Cerussite surfaces because of the presence of disulfide and polysulfide in the sulfidization products. In addition, a higher proportion of disulfide and polysulfide relative to the overall S is exhibited in the presence of chloride, facilitating the sulfidization flotation of Cerussite.
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dft study on the interaction between hydrogen sulfide ions and Cerussite 110 surface
Applied Surface Science, 2017Co-Authors: Qicheng Feng, Shuming Wen, Jiushuai Deng, Wenjuan ZhaoAbstract:Abstract The interaction between hydrogen sulfide ions (HS−) and the Cerussite surface was simulated using density functional theory (DFT) calculations. The calculated results show that Pb atoms are the dominating active sites for the subsequent reaction on the Cerussite (110) surface. The S atom in HS− ions can readily interact with the Pb atoms at the Cerussite surface layers with the interaction energy of −5.19 eV, resulting in the formation of lead sulfide species. An obvious difference occurs when HS− ions interact with the various Pb atoms on the Cerussite surface. The density of state analysis reveals that the Pb 6p orbital at the mineral surface layers and S 3p orbital from HS− ions are overlapped between −1.5 and 0.5 eV near the Fermi level, indicating a stable chemical adsorption. The Mulliken population result suggests that the electron transfer exists between the bonding atoms and the oxidation of the HS− ions is involved in the adsorption process. This study provides an insight into the sulfidization mechanism at an atomic level, and further confirms the experimental phenomenon proposed in our previous work.
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The Effect of Chloride Ions on the Activity of Cerussite Surfaces
Minerals, 2016Co-Authors: Qicheng Feng, Shuming Wen, Jiushuai Deng, Qin Bo Cao, Wenjuan ZhaoAbstract:Chloride ions were found to potentially increase activity of Cerussite surfaces. Dissolution experiments, zeta potential measurements, X-ray photoelectron spectroscopy (XPS) studies, and density functional theory (DFT) computation were conducted in this study. Dissolution experiments showed that the lead ion concentrations in the NaCl solution system were lower than those in the deionized water system and that the lead ion concentrations in NaCl + Na2S aqueous systems decreased by approximately one order of magnitude compared with that in the Na2S system alone. Results of zeta potential measurements revealed that the pretreatment with chloride ions of Cerussite caused a more positive zeta potential than that without chloride ions. XPS analysis results indicated that the number of lead ions on the mineral surface increased after Cerussite was treated with chloride ions. Results of DFT computation implied that the number of lead atoms on the mineral surface increased and that the activity improved after PbCl+ was adsorbed onto the Cerussite surface. The contribution of chloride ions to the activity on the mineral surface is attributed to the increase in the number of active sites and enhancement in the activity of these sites, resulting in improved sulfidization and flotation performance.
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a novel method for improving Cerussite sulfidization
International Journal of Minerals Metallurgy and Materials, 2016Co-Authors: Qicheng Feng, Shuming Wen, Wenjuan Zhao, Qin Bo CaoAbstract:Evaluation of flotation behavior, solution measurements, and surface analyses were performed to investigate the effects of chloride ion addition on the sulfidization of Cerussite in this study. Micro-flotation tests indicate that the addition of chloride ions prior to sulfidization can significantly increase the flotation recovery of Cerussite, which is attributed to the formation of more lead sulfide species on the mineral surface. Solution measurement results suggest that the addition of chloride ions prior to sulfidization induces the transformation of more sulfide ions from pulp solution onto the mineral surface by the formation of more lead sulfide species. X-ray diffraction and energy-dispersive spectroscopy indicate that more lead sulfide species form on the mineral surface when chloride ions are added prior to sulfidization. These results demonstrate that the addition of chloride ions prior to sulfidization can significantly improve the sulfidization of Cerussite, thereby enhancing the flotation performance.
Wenjuan Zhao - One of the best experts on this subject based on the ideXlab platform.
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combined dft and xps investigation of enhanced adsorption of sulfide species onto Cerussite by surface modification with chloride
Applied Surface Science, 2017Co-Authors: Qicheng Feng, Shuming Wen, Jiushuai Deng, Wenjuan ZhaoAbstract:Abstract This study systematically investigates the enhanced adsorption of sulfide species onto Cerussite by surface modification with chloride through density functional theory calculations and X-ray photoelectron spectroscopy (XPS) measurements. Calculation results demonstrate obvious differences in the surface structures and electronic properties of Cerussite after HS− adsorption in the absence and presence of chloride species. Surface modification with chloride promotes the stable adsorption of HS− onto the Cerussite surface, and the hybridization of Pb 6p orbital at the surface layer and S 3p orbital from HS− is enhanced. Moreover, the reactivity of Cerussite surfaces is enhanced by the occurrence of new DOS peaks of Pb 6p and S 3p near the Fermi level and by the transfer of additional electrons between the bonding atoms in the presence of chloride. Meanwhile, Mulliken population and XPS analysis results indicate that a slight oxidation is involved in the interaction between sulfide species and Cerussite surfaces because of the presence of disulfide and polysulfide in the sulfidization products. In addition, a higher proportion of disulfide and polysulfide relative to the overall S is exhibited in the presence of chloride, facilitating the sulfidization flotation of Cerussite.
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dft study on the interaction between hydrogen sulfide ions and Cerussite 110 surface
Applied Surface Science, 2017Co-Authors: Qicheng Feng, Shuming Wen, Jiushuai Deng, Wenjuan ZhaoAbstract:Abstract The interaction between hydrogen sulfide ions (HS−) and the Cerussite surface was simulated using density functional theory (DFT) calculations. The calculated results show that Pb atoms are the dominating active sites for the subsequent reaction on the Cerussite (110) surface. The S atom in HS− ions can readily interact with the Pb atoms at the Cerussite surface layers with the interaction energy of −5.19 eV, resulting in the formation of lead sulfide species. An obvious difference occurs when HS− ions interact with the various Pb atoms on the Cerussite surface. The density of state analysis reveals that the Pb 6p orbital at the mineral surface layers and S 3p orbital from HS− ions are overlapped between −1.5 and 0.5 eV near the Fermi level, indicating a stable chemical adsorption. The Mulliken population result suggests that the electron transfer exists between the bonding atoms and the oxidation of the HS− ions is involved in the adsorption process. This study provides an insight into the sulfidization mechanism at an atomic level, and further confirms the experimental phenomenon proposed in our previous work.
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The Effect of Chloride Ions on the Activity of Cerussite Surfaces
Minerals, 2016Co-Authors: Qicheng Feng, Shuming Wen, Jiushuai Deng, Qin Bo Cao, Wenjuan ZhaoAbstract:Chloride ions were found to potentially increase activity of Cerussite surfaces. Dissolution experiments, zeta potential measurements, X-ray photoelectron spectroscopy (XPS) studies, and density functional theory (DFT) computation were conducted in this study. Dissolution experiments showed that the lead ion concentrations in the NaCl solution system were lower than those in the deionized water system and that the lead ion concentrations in NaCl + Na2S aqueous systems decreased by approximately one order of magnitude compared with that in the Na2S system alone. Results of zeta potential measurements revealed that the pretreatment with chloride ions of Cerussite caused a more positive zeta potential than that without chloride ions. XPS analysis results indicated that the number of lead ions on the mineral surface increased after Cerussite was treated with chloride ions. Results of DFT computation implied that the number of lead atoms on the mineral surface increased and that the activity improved after PbCl+ was adsorbed onto the Cerussite surface. The contribution of chloride ions to the activity on the mineral surface is attributed to the increase in the number of active sites and enhancement in the activity of these sites, resulting in improved sulfidization and flotation performance.
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a novel method for improving Cerussite sulfidization
International Journal of Minerals Metallurgy and Materials, 2016Co-Authors: Qicheng Feng, Shuming Wen, Wenjuan Zhao, Qin Bo CaoAbstract:Evaluation of flotation behavior, solution measurements, and surface analyses were performed to investigate the effects of chloride ion addition on the sulfidization of Cerussite in this study. Micro-flotation tests indicate that the addition of chloride ions prior to sulfidization can significantly increase the flotation recovery of Cerussite, which is attributed to the formation of more lead sulfide species on the mineral surface. Solution measurement results suggest that the addition of chloride ions prior to sulfidization induces the transformation of more sulfide ions from pulp solution onto the mineral surface by the formation of more lead sulfide species. X-ray diffraction and energy-dispersive spectroscopy indicate that more lead sulfide species form on the mineral surface when chloride ions are added prior to sulfidization. These results demonstrate that the addition of chloride ions prior to sulfidization can significantly improve the sulfidization of Cerussite, thereby enhancing the flotation performance.
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effect of ph on surface characteristics and flotation of sulfidized Cerussite
Physicochemical Problems of Mineral Processing, 2016Co-Authors: Qicheng Feng, Shuming Wen, Wenjuan Zhao, Jian Liu, Dan LiuAbstract:The effect of pH on surface characteristic and flotation of sulfidized Cerussite was studied by micro-flotation tests, dissolution experiments, scanning electron microscopy (SEM) energy dispersive spectrometer (EDS), and X-ray photoelectron spectroscopy (XPS). The micro-flotation tests demonstrated that higher recovery of Cerussite was achieved in acidic solutions than that in alkaline solutions. Despite the addition of high collector concentrations, Cerussite flotation did not improved in alkaline solutions. The dissolution performance of sulfide-treated Cerussite at different pH values indicated that the lead sulfide layer on the surface of sulfide-treated Cerussite could exist in acidic solutions and it was more stable at acidic pH than in alkaline solutions. This finding was proved by the SEM-EDS and XPS analyses.
Shuming Wen - One of the best experts on this subject based on the ideXlab platform.
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adsorption characteristics of cu2 species on Cerussite surfaces and implications for sulfidization flotation
Separation and Purification Technology, 2021Co-Authors: Qian Zhang, Qicheng Feng, Shuming Wen, Yongchao MiaoAbstract:Abstract Metal ions are unavoidable in pulp solution, and they frequently influence the flotation recovery of minerals, such as by activation or depression. In this work, we systematically investigated the adsorption characteristics of Cu2+ species on Cerussite surfaces and the concomitant effect on sulfidization flotation by micro-flotation experiments and surface analysis. The flotation results indicated that the flotation recovery of Cerussite was almost unchanged at low Cu2+ concentration in the presence of Na2S, but it decreased at high Cu2+ concentration. X-ray photoelectron spectroscopy indicated that CuCO3 species formed on Cerussite surface in the presence of Cu2+, and Pb–S species and Cu–S species formed after Cu2+–Na2S treatment. Time-of-flight-secondary-ion mass spectrometry indicated that the distribution of lead species narrowed and that of copper species broadened with increasing Cu2+ concentration, which demonstrated that Cu2+ covered the mineral surfaces and inherent Pb2+ was shield. Ultraviolet–visible spectroscopy indicated that the stability of Cerussite surface increased with increasing amount of added Na2S. Compared with only Na2S treatment, consumption of xanthate was almost unchanged at low Cu2+ concentration, whereas consumption of xanthate considerably increased at high Cu2+ concentration, which may be because xanthate was consumed by the residual copper ions in the pulp solution. Zeta potential measurements indicated that Cu2+ can chemisorb on Cerussite surfaces and increasing the Cu2+ concentration facilitates adsorption of copper species, but it inhibits adsorption of Na2S and BX. Therefore, sulfidization flotation of Cerussite is not substantially affected by low concentrations of Cu2+, but is greatly affected by high concentrations of Cu2+.
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combined dft and xps investigation of enhanced adsorption of sulfide species onto Cerussite by surface modification with chloride
Applied Surface Science, 2017Co-Authors: Qicheng Feng, Shuming Wen, Jiushuai Deng, Wenjuan ZhaoAbstract:Abstract This study systematically investigates the enhanced adsorption of sulfide species onto Cerussite by surface modification with chloride through density functional theory calculations and X-ray photoelectron spectroscopy (XPS) measurements. Calculation results demonstrate obvious differences in the surface structures and electronic properties of Cerussite after HS− adsorption in the absence and presence of chloride species. Surface modification with chloride promotes the stable adsorption of HS− onto the Cerussite surface, and the hybridization of Pb 6p orbital at the surface layer and S 3p orbital from HS− is enhanced. Moreover, the reactivity of Cerussite surfaces is enhanced by the occurrence of new DOS peaks of Pb 6p and S 3p near the Fermi level and by the transfer of additional electrons between the bonding atoms in the presence of chloride. Meanwhile, Mulliken population and XPS analysis results indicate that a slight oxidation is involved in the interaction between sulfide species and Cerussite surfaces because of the presence of disulfide and polysulfide in the sulfidization products. In addition, a higher proportion of disulfide and polysulfide relative to the overall S is exhibited in the presence of chloride, facilitating the sulfidization flotation of Cerussite.
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dft study on the interaction between hydrogen sulfide ions and Cerussite 110 surface
Applied Surface Science, 2017Co-Authors: Qicheng Feng, Shuming Wen, Jiushuai Deng, Wenjuan ZhaoAbstract:Abstract The interaction between hydrogen sulfide ions (HS−) and the Cerussite surface was simulated using density functional theory (DFT) calculations. The calculated results show that Pb atoms are the dominating active sites for the subsequent reaction on the Cerussite (110) surface. The S atom in HS− ions can readily interact with the Pb atoms at the Cerussite surface layers with the interaction energy of −5.19 eV, resulting in the formation of lead sulfide species. An obvious difference occurs when HS− ions interact with the various Pb atoms on the Cerussite surface. The density of state analysis reveals that the Pb 6p orbital at the mineral surface layers and S 3p orbital from HS− ions are overlapped between −1.5 and 0.5 eV near the Fermi level, indicating a stable chemical adsorption. The Mulliken population result suggests that the electron transfer exists between the bonding atoms and the oxidation of the HS− ions is involved in the adsorption process. This study provides an insight into the sulfidization mechanism at an atomic level, and further confirms the experimental phenomenon proposed in our previous work.
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The Effect of Chloride Ions on the Activity of Cerussite Surfaces
Minerals, 2016Co-Authors: Qicheng Feng, Shuming Wen, Jiushuai Deng, Qin Bo Cao, Wenjuan ZhaoAbstract:Chloride ions were found to potentially increase activity of Cerussite surfaces. Dissolution experiments, zeta potential measurements, X-ray photoelectron spectroscopy (XPS) studies, and density functional theory (DFT) computation were conducted in this study. Dissolution experiments showed that the lead ion concentrations in the NaCl solution system were lower than those in the deionized water system and that the lead ion concentrations in NaCl + Na2S aqueous systems decreased by approximately one order of magnitude compared with that in the Na2S system alone. Results of zeta potential measurements revealed that the pretreatment with chloride ions of Cerussite caused a more positive zeta potential than that without chloride ions. XPS analysis results indicated that the number of lead ions on the mineral surface increased after Cerussite was treated with chloride ions. Results of DFT computation implied that the number of lead atoms on the mineral surface increased and that the activity improved after PbCl+ was adsorbed onto the Cerussite surface. The contribution of chloride ions to the activity on the mineral surface is attributed to the increase in the number of active sites and enhancement in the activity of these sites, resulting in improved sulfidization and flotation performance.
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a novel method for improving Cerussite sulfidization
International Journal of Minerals Metallurgy and Materials, 2016Co-Authors: Qicheng Feng, Shuming Wen, Wenjuan Zhao, Qin Bo CaoAbstract:Evaluation of flotation behavior, solution measurements, and surface analyses were performed to investigate the effects of chloride ion addition on the sulfidization of Cerussite in this study. Micro-flotation tests indicate that the addition of chloride ions prior to sulfidization can significantly increase the flotation recovery of Cerussite, which is attributed to the formation of more lead sulfide species on the mineral surface. Solution measurement results suggest that the addition of chloride ions prior to sulfidization induces the transformation of more sulfide ions from pulp solution onto the mineral surface by the formation of more lead sulfide species. X-ray diffraction and energy-dispersive spectroscopy indicate that more lead sulfide species form on the mineral surface when chloride ions are added prior to sulfidization. These results demonstrate that the addition of chloride ions prior to sulfidization can significantly improve the sulfidization of Cerussite, thereby enhancing the flotation performance.
Victor Gonzalez - One of the best experts on this subject based on the ideXlab platform.
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Synchrotron-based high angle resolution and high lateral resolution X-ray diffraction reveals lead white pigment qualities in Old Masters paintings
Analytical Chemistry, 2017Co-Authors: Victor Gonzalez, Thomas Calligaro, Gilles Wallez, Marine Cotte, Myriam Eveno, Elisabeth Ravaud, Wout De Nolf, Michel MenuAbstract:Micro-samples collected on 28 major paintings by Old European Masters dating from the Middle Ages to the late 19th c. were analyzed using Synchrotron-based X-ray diffraction. Two complementary analytical configurations were used at beamlines ID22 (high-angle resolution) and ID21 (high lateral resolution), in order to highlight markers of the different grades of the lead white pigments (mixture of Cerussite PbCO3 and hydroCerussite Pb3(CO3)2(OH)2). Rietveld analysis and crystalline phases mapping at the micro-scale revealed the composition and microstructure of the pigments, shedding light on the preparation recipes and pigment choices of the artists through History.
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synchrotron based high angle resolution and high lateral resolution x ray diffraction revealing lead white pigment qualities in old masters paintings
Analytical Chemistry, 2017Co-Authors: Thomas Calligaro, Victor Gonzalez, Gilles Wallez, Marine Cotte, Myriam Eveno, Wout De Nolf, Elisabeth RavaudAbstract:Microsamples collected on 27 major paintings by Old European Masters dating from the 14th to the late 19th centuries were analyzed using synchrotron-based X-ray diffraction. Two complementary analytical configurations were used at beamlines ID22 (high angle resolution) and ID21 (high lateral resolution), in order to highlight markers of the different grades of the lead white pigments (mixture of Cerussite PbCO3 and hydroCerussite Pb3(CO3)2(OH)2). Rietveld analysis and crystalline phases mapping at the microscale revealed the composition and microstructure of the pigments, shedding light on the preparation recipes and pigment choices of the artists through History.
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Revealing the Origin and History of Lead-White Pigments by Their Photoluminescence Properties
2017Co-Authors: Victor Gonzalez, Thomas Calligaro, Gilles Wallez, Didier Gourier, Kathleen Toussaint, Michel MenuAbstract:The lead white pigment, composed of two main mineral phases Cerussite PbCO3 and hydroCerussite 2PbCO3·Pb(OH)2, has been used in paintings since the Antiquity. The study of historical sources revealed that a large variety of lead white qualities were proposed, depending on the degree of sophistication of the pigment synthesis. Investigation of photoluminescence of the two constitutive mineral phases gave insight into the origin of the visible emission of these materials and emphasized the influence of structural defects on their photoluminescence properties. These effects were observed by combining emission and excitation spectra in two-dimensional representations. For each excitation wavelength, between 250 and 400 nm (4.9–3.1 eV), luminescence spectra were collected between 400 and 800 nm (3.1–1.5 eV). Two types of emission-excitation bands were identified: an emission excited in the optical bandgap of the compounds (about 5 eV), which depends on the constitutive phase (2.8 eV in Cerussite and 2.1 eV in hydroCerussite), and broad emission bands in the same energy range excited below the optical gap, which are sensitive to the synthesis method and the nature of postsynthesis treatments. It is proposed that this sensitivity of photoluminescence properties of lead-white pigments could be used as fingerprints of their origin and history
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Synchrotron-Based High Angle Resolution and High Lateral Resolution X‑ray Diffraction: Revealing Lead White Pigment Qualities in Old Masters Paintings
2017Co-Authors: Victor Gonzalez, Thomas Calligaro, Gilles Wallez, Marine Cotte, Myriam Eveno, Elisabeth Ravaud, Wout De Nolf, Michel MenuAbstract:Microsamples collected on 27 major paintings by Old European Masters dating from the 14th to the late 19th centuries were analyzed using synchrotron-based X-ray diffraction. Two complementary analytical configurations were used at beamlines ID22 (high angle resolution) and ID21 (high lateral resolution), in order to highlight markers of the different grades of the lead white pigments (mixture of Cerussite PbCO3 and hydroCerussite Pb3(CO3)2(OH)2). Rietveld analysis and crystalline phases mapping at the microscale revealed the composition and microstructure of the pigments, shedding light on the preparation recipes and pigment choices of the artists through History
Gilles Wallez - One of the best experts on this subject based on the ideXlab platform.
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Synchrotron-based high angle resolution and high lateral resolution X-ray diffraction reveals lead white pigment qualities in Old Masters paintings
Analytical Chemistry, 2017Co-Authors: Victor Gonzalez, Thomas Calligaro, Gilles Wallez, Marine Cotte, Myriam Eveno, Elisabeth Ravaud, Wout De Nolf, Michel MenuAbstract:Micro-samples collected on 28 major paintings by Old European Masters dating from the Middle Ages to the late 19th c. were analyzed using Synchrotron-based X-ray diffraction. Two complementary analytical configurations were used at beamlines ID22 (high-angle resolution) and ID21 (high lateral resolution), in order to highlight markers of the different grades of the lead white pigments (mixture of Cerussite PbCO3 and hydroCerussite Pb3(CO3)2(OH)2). Rietveld analysis and crystalline phases mapping at the micro-scale revealed the composition and microstructure of the pigments, shedding light on the preparation recipes and pigment choices of the artists through History.
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synchrotron based high angle resolution and high lateral resolution x ray diffraction revealing lead white pigment qualities in old masters paintings
Analytical Chemistry, 2017Co-Authors: Thomas Calligaro, Victor Gonzalez, Gilles Wallez, Marine Cotte, Myriam Eveno, Wout De Nolf, Elisabeth RavaudAbstract:Microsamples collected on 27 major paintings by Old European Masters dating from the 14th to the late 19th centuries were analyzed using synchrotron-based X-ray diffraction. Two complementary analytical configurations were used at beamlines ID22 (high angle resolution) and ID21 (high lateral resolution), in order to highlight markers of the different grades of the lead white pigments (mixture of Cerussite PbCO3 and hydroCerussite Pb3(CO3)2(OH)2). Rietveld analysis and crystalline phases mapping at the microscale revealed the composition and microstructure of the pigments, shedding light on the preparation recipes and pigment choices of the artists through History.
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Revealing the Origin and History of Lead-White Pigments by Their Photoluminescence Properties
2017Co-Authors: Victor Gonzalez, Thomas Calligaro, Gilles Wallez, Didier Gourier, Kathleen Toussaint, Michel MenuAbstract:The lead white pigment, composed of two main mineral phases Cerussite PbCO3 and hydroCerussite 2PbCO3·Pb(OH)2, has been used in paintings since the Antiquity. The study of historical sources revealed that a large variety of lead white qualities were proposed, depending on the degree of sophistication of the pigment synthesis. Investigation of photoluminescence of the two constitutive mineral phases gave insight into the origin of the visible emission of these materials and emphasized the influence of structural defects on their photoluminescence properties. These effects were observed by combining emission and excitation spectra in two-dimensional representations. For each excitation wavelength, between 250 and 400 nm (4.9–3.1 eV), luminescence spectra were collected between 400 and 800 nm (3.1–1.5 eV). Two types of emission-excitation bands were identified: an emission excited in the optical bandgap of the compounds (about 5 eV), which depends on the constitutive phase (2.8 eV in Cerussite and 2.1 eV in hydroCerussite), and broad emission bands in the same energy range excited below the optical gap, which are sensitive to the synthesis method and the nature of postsynthesis treatments. It is proposed that this sensitivity of photoluminescence properties of lead-white pigments could be used as fingerprints of their origin and history
-
Synchrotron-Based High Angle Resolution and High Lateral Resolution X‑ray Diffraction: Revealing Lead White Pigment Qualities in Old Masters Paintings
2017Co-Authors: Victor Gonzalez, Thomas Calligaro, Gilles Wallez, Marine Cotte, Myriam Eveno, Elisabeth Ravaud, Wout De Nolf, Michel MenuAbstract:Microsamples collected on 27 major paintings by Old European Masters dating from the 14th to the late 19th centuries were analyzed using synchrotron-based X-ray diffraction. Two complementary analytical configurations were used at beamlines ID22 (high angle resolution) and ID21 (high lateral resolution), in order to highlight markers of the different grades of the lead white pigments (mixture of Cerussite PbCO3 and hydroCerussite Pb3(CO3)2(OH)2). Rietveld analysis and crystalline phases mapping at the microscale revealed the composition and microstructure of the pigments, shedding light on the preparation recipes and pigment choices of the artists through History