Insaf Daldoul | Université Laval (original) (raw)

Papers by Insaf Daldoul

Research paper thumbnail of Caractérisation et étude de la performance du chrysotile dans la capture du dioxyde de carbone dans les procédés gaz-solide

Ratification of the Kyoto Protocol by Canada in December 2002 and the environmental standards bei... more Ratification of the Kyoto Protocol by Canada in December 2002 and the environmental standards being implemented worldwide already anticipate on finding solutions to reduce significantly the emissions of greenhouse gases, especially CO2. One way to reduce such emissions is to sequester CO2 by mineral carbonation using magnesium silicates. These minerals are abundant in Asbestos mines in Southern Quebec. This study therefore reviews current and developing processes for CO2 capture and an in-depth study of low-pressure gas-solid carbonation of chrysotile in dry and moist environments. The evolving structure of chrysotile and its reactivity as a function of temperature, moisture and CO2 composition, thermal preconditioning, and alkali metal doping have been monitored through TG-DTAMS, X-ray photoelectron spectroscopy and X-ray powder diffraction. The most important result of this study was that chrysotile doped with 10w/w% Cs, in a moist environment, promotes CO2 fixation by up to a fac...

Research paper thumbnail of Numerical study of the diffusion of binary hydrocarbon blends in ZSM-12 zeolites

Microporous and Mesoporous Materials

Research paper thumbnail of Fixation of CO 2 by chrysotile in low-pressure dry and moist carbonation: Ex-situ and in-situ characterizations

Geochimica Et Cosmochimica Acta, 2010

A detailed study of low-pressure gas-solid carbonation of chrysotile in dry and humid environment... more A detailed study of low-pressure gas-solid carbonation of chrysotile in dry and humid environments has been carried out. The evolving structure of chrysotile and its reactivity as a function of temperature (300-1200°C), humidity (0-10 mol %) and CO 2 partial pressure (20-67 mol %), thermal preconditioning, and alkali metal doping (Li, Na, K, Cs) have been monitored through in-situ X-ray photoelectron spectroscopy, isothermal thermogravimetry/mass spectrometry, ex-situ X-ray powder diffraction, and water and nitrogen adsorption/desorption. Based on chrysotile crystalline structure and its nanofibrilar orderliness, a multistep carbonation mechanism was elaborated to explain the role of water during chrysotile partial amorphisation, formation of periclase, brucite, and hydromagnesite crystalline phases, and surface passivation thereof, during humid carbonation. The weak carbonation reactivity was rationalized in terms of incongruent CO 2 van der Waals molecular diameters with the octahedral-tetrahedral lattice constants of chrysotile. This lack of reactivity appeared to be relatively indifferent to the facilitated water crisscrossing during chrysotile core dehydroxylation/pseudo-amorphisation and surface hydroxylation induced product stabilization during humid carbonation. Thermodynamic stability domains of the species observed at low pressure have been thoroughly discussed on the basis of X-ray powder diffraction patterns and X-ray photoelectron spectroscopy evidence. The highest carbon dioxide uptake occurred at 375°C in moist atmospheres. On the basis of chrysotile fresh N 2 BET area, nearly 15 atoms out of 100 of the surface chrysotile brucitic Mg moiety have been carbonated at this temperature which was tantamount to the carbonation of about 2.5 at. % of the total brucitic Mg moiety in chrysotile. The carbonation of brucite (Mg(OH) 2 ) impurities coexisting in chrysotile was minor and estimated to contribute by less than 17.6 at. % of the total converted magnesium. The presence of cesium traces (3 Cs atoms per 100 Mg atoms) was found to boost chrysotile carbonation capacity by a factor 2.7.

Research paper thumbnail of Fixation of CO2 by chrysotile in low-pressure dry and moist carbonation: Ex-situ and in-situ characterizations

Geochimica Et Cosmochimica Acta, 2010

A detailed study of low-pressure gas-solid carbonation of chrysotile in dry and humid environment... more A detailed study of low-pressure gas-solid carbonation of chrysotile in dry and humid environments has been carried out. The evolving structure of chrysotile and its reactivity as a function of temperature (300-1200 °C), humidity (0-10 mol %) and CO 2 partial pressure (20-67 mol %), thermal preconditioning, and alkali metal doping (Li, Na, K, Cs) have been monitored through in-situ X-ray photoelectron spectroscopy, isothermal thermogravimetry/mass spectrometry, ex-situ X-ray powder diffraction, and water and nitrogen adsorption/desorption. Based on chrysotile crystalline structure and its nanofibrilar orderliness, a multistep carbonation mechanism was elaborated to explain the role of water during chrysotile partial amorphisation, formation of periclase, brucite, and hydromagnesite crystalline phases, and surface passivation thereof, during humid carbonation. The weak carbonation reactivity was rationalized in terms of incongruent CO 2 van der Waals molecular diameters with the octahedral-tetrahedral lattice constants of chrysotile. This lack of reactivity appeared to be relatively indifferent to the facilitated water crisscrossing during chrysotile core dehydroxylation/pseudo-amorphisation and surface hydroxylation induced product stabilization during humid carbonation. Thermodynamic stability domains of the species observed at low pressure have been thoroughly discussed on the basis of X-ray powder diffraction patterns and X-ray photoelectron spectroscopy evidence. The highest carbon dioxide uptake occurred at 375 °C in moist atmospheres. On the basis of chrysotile fresh N 2 BET area, nearly 15 atoms out of 100 of the surface chrysotile brucitic Mg moiety have been carbonated at this temperature which was tantamount to the carbonation of about 2.5 at. % of the total brucitic Mg moiety in chrysotile. The carbonation of brucite (Mg(OH) 2) impurities coexisting in chrysotile was minor and estimated to contribute by less than 17.6 at. % of the total converted magnesium. The presence of cesium traces (3 Cs atoms per 100 Mg atoms) was found to boost chrysotile carbonation capacity by a factor 2.7.

Research paper thumbnail of Caractérisation et étude de la performance du chrysotile dans la capture du dioxyde de carbone dans les procédés gaz-solide

Ratification of the Kyoto Protocol by Canada in December 2002 and the environmental standards bei... more Ratification of the Kyoto Protocol by Canada in December 2002 and the environmental standards being implemented worldwide already anticipate on finding solutions to reduce significantly the emissions of greenhouse gases, especially CO2. One way to reduce such emissions is to sequester CO2 by mineral carbonation using magnesium silicates. These minerals are abundant in Asbestos mines in Southern Quebec. This study therefore reviews current and developing processes for CO2 capture and an in-depth study of low-pressure gas-solid carbonation of chrysotile in dry and moist environments. The evolving structure of chrysotile and its reactivity as a function of temperature, moisture and CO2 composition, thermal preconditioning, and alkali metal doping have been monitored through TG-DTAMS, X-ray photoelectron spectroscopy and X-ray powder diffraction. The most important result of this study was that chrysotile doped with 10w/w% Cs, in a moist environment, promotes CO2 fixation by up to a fac...

Research paper thumbnail of Numerical study of the diffusion of binary hydrocarbon blends in ZSM-12 zeolites

Microporous and Mesoporous Materials

Research paper thumbnail of Fixation of CO 2 by chrysotile in low-pressure dry and moist carbonation: Ex-situ and in-situ characterizations

Geochimica Et Cosmochimica Acta, 2010

A detailed study of low-pressure gas-solid carbonation of chrysotile in dry and humid environment... more A detailed study of low-pressure gas-solid carbonation of chrysotile in dry and humid environments has been carried out. The evolving structure of chrysotile and its reactivity as a function of temperature (300-1200°C), humidity (0-10 mol %) and CO 2 partial pressure (20-67 mol %), thermal preconditioning, and alkali metal doping (Li, Na, K, Cs) have been monitored through in-situ X-ray photoelectron spectroscopy, isothermal thermogravimetry/mass spectrometry, ex-situ X-ray powder diffraction, and water and nitrogen adsorption/desorption. Based on chrysotile crystalline structure and its nanofibrilar orderliness, a multistep carbonation mechanism was elaborated to explain the role of water during chrysotile partial amorphisation, formation of periclase, brucite, and hydromagnesite crystalline phases, and surface passivation thereof, during humid carbonation. The weak carbonation reactivity was rationalized in terms of incongruent CO 2 van der Waals molecular diameters with the octahedral-tetrahedral lattice constants of chrysotile. This lack of reactivity appeared to be relatively indifferent to the facilitated water crisscrossing during chrysotile core dehydroxylation/pseudo-amorphisation and surface hydroxylation induced product stabilization during humid carbonation. Thermodynamic stability domains of the species observed at low pressure have been thoroughly discussed on the basis of X-ray powder diffraction patterns and X-ray photoelectron spectroscopy evidence. The highest carbon dioxide uptake occurred at 375°C in moist atmospheres. On the basis of chrysotile fresh N 2 BET area, nearly 15 atoms out of 100 of the surface chrysotile brucitic Mg moiety have been carbonated at this temperature which was tantamount to the carbonation of about 2.5 at. % of the total brucitic Mg moiety in chrysotile. The carbonation of brucite (Mg(OH) 2 ) impurities coexisting in chrysotile was minor and estimated to contribute by less than 17.6 at. % of the total converted magnesium. The presence of cesium traces (3 Cs atoms per 100 Mg atoms) was found to boost chrysotile carbonation capacity by a factor 2.7.

Research paper thumbnail of Fixation of CO2 by chrysotile in low-pressure dry and moist carbonation: Ex-situ and in-situ characterizations

Geochimica Et Cosmochimica Acta, 2010

A detailed study of low-pressure gas-solid carbonation of chrysotile in dry and humid environment... more A detailed study of low-pressure gas-solid carbonation of chrysotile in dry and humid environments has been carried out. The evolving structure of chrysotile and its reactivity as a function of temperature (300-1200 °C), humidity (0-10 mol %) and CO 2 partial pressure (20-67 mol %), thermal preconditioning, and alkali metal doping (Li, Na, K, Cs) have been monitored through in-situ X-ray photoelectron spectroscopy, isothermal thermogravimetry/mass spectrometry, ex-situ X-ray powder diffraction, and water and nitrogen adsorption/desorption. Based on chrysotile crystalline structure and its nanofibrilar orderliness, a multistep carbonation mechanism was elaborated to explain the role of water during chrysotile partial amorphisation, formation of periclase, brucite, and hydromagnesite crystalline phases, and surface passivation thereof, during humid carbonation. The weak carbonation reactivity was rationalized in terms of incongruent CO 2 van der Waals molecular diameters with the octahedral-tetrahedral lattice constants of chrysotile. This lack of reactivity appeared to be relatively indifferent to the facilitated water crisscrossing during chrysotile core dehydroxylation/pseudo-amorphisation and surface hydroxylation induced product stabilization during humid carbonation. Thermodynamic stability domains of the species observed at low pressure have been thoroughly discussed on the basis of X-ray powder diffraction patterns and X-ray photoelectron spectroscopy evidence. The highest carbon dioxide uptake occurred at 375 °C in moist atmospheres. On the basis of chrysotile fresh N 2 BET area, nearly 15 atoms out of 100 of the surface chrysotile brucitic Mg moiety have been carbonated at this temperature which was tantamount to the carbonation of about 2.5 at. % of the total brucitic Mg moiety in chrysotile. The carbonation of brucite (Mg(OH) 2) impurities coexisting in chrysotile was minor and estimated to contribute by less than 17.6 at. % of the total converted magnesium. The presence of cesium traces (3 Cs atoms per 100 Mg atoms) was found to boost chrysotile carbonation capacity by a factor 2.7.