The capacity to capture CO_2 was determined in several stoichiometric compositions in the Li_2O–Bi_2O_3 system. The compounds(Li_7BiO_6, Li_5BiO_5, Li_3BiO_4 and LiBiO_2 phases) were synthesized via solid-state react...The capacity to capture CO_2 was determined in several stoichiometric compositions in the Li_2O–Bi_2O_3 system. The compounds(Li_7BiO_6, Li_5BiO_5, Li_3BiO_4 and LiBiO_2 phases) were synthesized via solid-state reaction and characterized by X-ray diffraction, scanning electron microscopy and N2 adsorption techniques.The samples were heat-treated at temperatures from 40 to 750 °C under the CO_2 atmosphere to evaluate the carbonate formation, which is indicative of the capacity of CO_2 capture. Moreover, Li_7BiO_6 shows an excellent CO_2 capture capacity of 7.1 mmol/g, which is considerably higher than those of other previously reported ceramics. Li_7BiO_6 is able to react with CO_2 from 240 °C to approximately 660 °C showing a high kinetic reaction even at CO_2 partial pressure values as low as 0.05.展开更多
This investigation demonstrates the feasibility to fabricate high quality ceramic–carbonate membranes based on mixed-conducting ceramics.Specifically,it is reported the simultaneous CO2/O2 permeation and stability pr...This investigation demonstrates the feasibility to fabricate high quality ceramic–carbonate membranes based on mixed-conducting ceramics.Specifically,it is reported the simultaneous CO2/O2 permeation and stability properties of membranes constituted by a combination of ceramic and carbonate phases,wherein the microstructure of the ceramic part is composed,in turn,of a mixture of fluorite and perovskite phases.These ceramics showed ionic and electronic conduction,and at the operation temperature,the carbonate phase of the membranes is in liquid state,which allows the transport of CO32-and O2–species via different mechanisms.To fabricate the membranes,the ceramic powders were uniaxially pressed in a disk shape.Then,an incipient sintering treatment was carried out in such a way that a highly porous ceramic was obtained.Afterwards,the piece is densified by the infiltration of molten carbonate.Characterization of the membranes was accomplished by SEM,XRD,and gas permeation techniques among others.Thermal and chemical stability under an atmosphere rich in CO2 was evaluated.CO2/O2 permeation and long-term stability measurements were conducted between 850 and 940℃.The best permeation–separation performance of membranes of about 1 mm thickness,showed a maximum permeance flux of about 4.46×10^–7 mol·m^–2·s^–1·Pa^–1 for CO2 and 2.18×10^–7 mol·m^–2·s^–1·Pa^–1 for O2 at 940℃.Membranes exhibited separation factor values of 150–991 and 49–511 for CO2/N2 and O2/N2 respectively in the studied temperature range.Despite long-term stability test showed certain microstructural changes in the membranes,no significant detriment on the permeation properties was observed along 100 h of continuous operation.展开更多
文摘The capacity to capture CO_2 was determined in several stoichiometric compositions in the Li_2O–Bi_2O_3 system. The compounds(Li_7BiO_6, Li_5BiO_5, Li_3BiO_4 and LiBiO_2 phases) were synthesized via solid-state reaction and characterized by X-ray diffraction, scanning electron microscopy and N2 adsorption techniques.The samples were heat-treated at temperatures from 40 to 750 °C under the CO_2 atmosphere to evaluate the carbonate formation, which is indicative of the capacity of CO_2 capture. Moreover, Li_7BiO_6 shows an excellent CO_2 capture capacity of 7.1 mmol/g, which is considerably higher than those of other previously reported ceramics. Li_7BiO_6 is able to react with CO_2 from 240 °C to approximately 660 °C showing a high kinetic reaction even at CO_2 partial pressure values as low as 0.05.
基金supported by Proyectos de Investigación Científica y Desarrollo Tecnológico SIP-IPN No.20190014。
文摘This investigation demonstrates the feasibility to fabricate high quality ceramic–carbonate membranes based on mixed-conducting ceramics.Specifically,it is reported the simultaneous CO2/O2 permeation and stability properties of membranes constituted by a combination of ceramic and carbonate phases,wherein the microstructure of the ceramic part is composed,in turn,of a mixture of fluorite and perovskite phases.These ceramics showed ionic and electronic conduction,and at the operation temperature,the carbonate phase of the membranes is in liquid state,which allows the transport of CO32-and O2–species via different mechanisms.To fabricate the membranes,the ceramic powders were uniaxially pressed in a disk shape.Then,an incipient sintering treatment was carried out in such a way that a highly porous ceramic was obtained.Afterwards,the piece is densified by the infiltration of molten carbonate.Characterization of the membranes was accomplished by SEM,XRD,and gas permeation techniques among others.Thermal and chemical stability under an atmosphere rich in CO2 was evaluated.CO2/O2 permeation and long-term stability measurements were conducted between 850 and 940℃.The best permeation–separation performance of membranes of about 1 mm thickness,showed a maximum permeance flux of about 4.46×10^–7 mol·m^–2·s^–1·Pa^–1 for CO2 and 2.18×10^–7 mol·m^–2·s^–1·Pa^–1 for O2 at 940℃.Membranes exhibited separation factor values of 150–991 and 49–511 for CO2/N2 and O2/N2 respectively in the studied temperature range.Despite long-term stability test showed certain microstructural changes in the membranes,no significant detriment on the permeation properties was observed along 100 h of continuous operation.
