The world is currently facing the challenges of global warming and climate change. Numerous efforts have been taken to mitigate CO2 emission, among which is the use of solid sorbents for CO2 capture. In this work, Li4...The world is currently facing the challenges of global warming and climate change. Numerous efforts have been taken to mitigate CO2 emission, among which is the use of solid sorbents for CO2 capture. In this work, Li4SiO4 was synthesised via a sol-gel method using lithium nitrate （LiNO3） and tetraethylorthosilicate （SiC8H20O4） as precursors. A parametric study of Li：Si molar ratio （1-5）, calcination temperature （600-800℃） and calcination time （1-8 h） were conducted during sorbent synthesis. Calcination temperature （700-800℃） and carbonation temperature （500-700℃） during CO2 sorption activity were also varied to confirm the optimum operating temperature. Sorbent with the highest CO2 sorption capacity was finally introduced to several cyclic tests to study the durability of the sorbent through 10 cycles of CO2 sorption-desorption test. The results showed that the calcination temperature of 800℃ and carbonation temperature of 700℃ were the best operating temperatures, with CO2 sorption capacity of 7.95 mmol CO2·（g sorbent）^-1 （93% of the theoretical yield）. Throughout the ten cyclic processes, CO2 sorption capacity of the sorbent had dropped approximately 16.2% from the first to the tenth cycle, which was a reasonable decline. Thus, it was concluded that Li4SiO4 is a potential CO2 solid sorbent for high temperature CO2 capture activity.展开更多
Li4SiO4 ceramic pebble is considered as a candidate tritium breeding material of Chinese Helium Cooled Solid Breeder Test Blanket Module （CH HCSB TBM） for the International Thermonuclear Experimental Reactor （ITER...Li4SiO4 ceramic pebble is considered as a candidate tritium breeding material of Chinese Helium Cooled Solid Breeder Test Blanket Module （CH HCSB TBM） for the International Thermonuclear Experimental Reactor （ITER）. In this paper, LiaSiO4 ceramic pebbles deposited with catalytic metals, including Pt, Pd, Ru and Ir, were prepared by wet impregnation method. The metal particles on Li4SiO4 pebble exhibit a good promotion of hydrogen isotope exchange reactions in H2-D20 gas system, with conversion equilibrium temperature reduction of 200-300 ~C. The out-of-pile tritium release experiments were performed using 1.0 wt% Pt/Li4SiO4 and Li4SiO4 pebbles irradiated in a thermal neutron reactor. The thermal desorption spectroscopy shows that Pt was effective to increase the tritium release rate at lower temperatures, and the ratio of tritium molecule （HT） to tritiated water （HTO） of 1.0 wt% Pt/LiaSiO4 was much more than that of Li4SiO4, which released mainly as HTO. Thus, catalytic metals deposited on LiaSiO4 pebble may help to accelerate the recovery of bred tritium particularly in low temperature region, and increase the tritium molecule form released from the tritium breedin~ materials.展开更多
It is urgent to develop excellent solid CO<sub>2</sub> sorbents with higher sorption capacity, simpler synthetic process, better thermal stability and lower costs of synthesis in CO<sub>2</sub>...It is urgent to develop excellent solid CO<sub>2</sub> sorbents with higher sorption capacity, simpler synthetic process, better thermal stability and lower costs of synthesis in CO<sub>2</sub> capture and storage technologies. In this work, a number of Li<sub>4</sub>SiO<sub>4</sub>-based sorbents synthesized by lithium carbonate with three different kinds of fly ashes in various molar ratios were developed. The results indicate that the Li<sub>2</sub>CO<sub>3</sub>:SiO<sub>2</sub> mole ratio used in the sorbents synthesis significantly affects the CO<sub>2</sub> absorption properties. The sorption capacity increased with the excess of Li<sub>2</sub>CO<sub>3</sub> first and then decreased when the excessive quantity was beyond a certain amount. The experiments found that FA-Li<sub>4</sub>SiO<sub>4</sub>_0.6, CFA-Li<sub>4</sub>SiO<sub>4</sub>_0.4, HCl/CFA-Li<sub>4</sub>SiO<sub>4</sub>_0.3 presented the best sorption ability among these fly ash derived Li<sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;">SiO</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;"> samples, and the corresponding weight gain was 28.2 wt%, 25.1 wt% and 32.5 wt%, respectively. The three sorbents with the optimal molar ratio were characterized using various morphological </span><span style="font-family:Verdana;">characterization techniques and evaluated by thermogravimetric analysis </span><span style="font-family:Verdana;">for their capacity to chemisorb CO<sub>2</sub> at 450<sup></sup></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;"><span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span></span><span style="font-family:Verdana;"></span><span style="font-family:Verdana;">C</span><span style="font-family:Verdana;"> - 650<sup></sup></span><span style="font-family:Verdana;"><span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span></span><span style="font-family:Verdana;"></span><span style="font-family:Verdana;">C</span><span style="font-family:Verdana;">, diluted CO<sub>2</sub> (10%, 20%) and in presence of water vapor (12%). The adsorption curve of FA- Li<sub>4</sub>SiO<sub>4</sub>_0.6 at different temperatures was simulated with the Jander-Zhang model to explore the influence of carbon dioxide diffusion on adsorption reaction. Further experiments showed that the adsorbent had a good sorption capacity in a lower partial pressure of CO<sub>2</sub> and the presence of steam enhanced the mobility of Li<sup>+</sup>. What’s more, FA-Li<sub>4</sub>SiO<sub>4</sub>_0.6, CFA-Li<sub>4</sub>SiO<sub>4</sub>_0.4 and HCl/CFA-Li<sub>4</sub>SiO<sub>4</sub>_0.3 particles showed satisfactory sorption capacity in fixed-bed reactor and excellent cyclic sorption stability during 10 sorption/ desorption cycles.</span></span></span></span>展开更多
Li2Fe0.9Mn0.1SiO4/C composites were synthesized by using X-ray diffractometry （XRD）, scanning electron microscopy （SEM） glucose as carbon source. The samples were characterized by and electrochemical measurements....Li2Fe0.9Mn0.1SiO4/C composites were synthesized by using X-ray diffractometry （XRD）, scanning electron microscopy （SEM） glucose as carbon source. The samples were characterized by and electrochemical measurements. All Li2Fe0.9Mn0.1SiO4/C composites are of the similar crystal structure. With increasing the carbon content in the range of 5%-20% （mass fraction）, the diffraction peaks in XRD patterns broaden and the particle sizes and the tap density of samples decrease. The Li2Fe0.9Mn0.1SiO4/C composites with carbon content of 14.12% show excellent electrochemical performances with an initial discharge capacity of 154.7 mA.h/g at C/16 rate, and the capacity retention remains 92.2% after 30 cycles.展开更多
基金fully sponsored by the Ministry of Education of Malaysia and Universiti Sains Malaysia through LRGS-USM Nano MITe Grant (203/PJKIMIA/6720009)
文摘The world is currently facing the challenges of global warming and climate change. Numerous efforts have been taken to mitigate CO2 emission, among which is the use of solid sorbents for CO2 capture. In this work, Li4SiO4 was synthesised via a sol-gel method using lithium nitrate （LiNO3） and tetraethylorthosilicate （SiC8H20O4） as precursors. A parametric study of Li：Si molar ratio （1-5）, calcination temperature （600-800℃） and calcination time （1-8 h） were conducted during sorbent synthesis. Calcination temperature （700-800℃） and carbonation temperature （500-700℃） during CO2 sorption activity were also varied to confirm the optimum operating temperature. Sorbent with the highest CO2 sorption capacity was finally introduced to several cyclic tests to study the durability of the sorbent through 10 cycles of CO2 sorption-desorption test. The results showed that the calcination temperature of 800℃ and carbonation temperature of 700℃ were the best operating temperatures, with CO2 sorption capacity of 7.95 mmol CO2·（g sorbent）^-1 （93% of the theoretical yield）. Throughout the ten cyclic processes, CO2 sorption capacity of the sorbent had dropped approximately 16.2% from the first to the tenth cycle, which was a reasonable decline. Thus, it was concluded that Li4SiO4 is a potential CO2 solid sorbent for high temperature CO2 capture activity.
基金supported by the Development Fund of China Academy of Engineering Physics (No.2010B0301035)the National Magnetic Confinement Fusion Science Program (No. 2010GB112004)
文摘Li4SiO4 ceramic pebble is considered as a candidate tritium breeding material of Chinese Helium Cooled Solid Breeder Test Blanket Module （CH HCSB TBM） for the International Thermonuclear Experimental Reactor （ITER）. In this paper, LiaSiO4 ceramic pebbles deposited with catalytic metals, including Pt, Pd, Ru and Ir, were prepared by wet impregnation method. The metal particles on Li4SiO4 pebble exhibit a good promotion of hydrogen isotope exchange reactions in H2-D20 gas system, with conversion equilibrium temperature reduction of 200-300 ~C. The out-of-pile tritium release experiments were performed using 1.0 wt% Pt/Li4SiO4 and Li4SiO4 pebbles irradiated in a thermal neutron reactor. The thermal desorption spectroscopy shows that Pt was effective to increase the tritium release rate at lower temperatures, and the ratio of tritium molecule （HT） to tritiated water （HTO） of 1.0 wt% Pt/LiaSiO4 was much more than that of Li4SiO4, which released mainly as HTO. Thus, catalytic metals deposited on LiaSiO4 pebble may help to accelerate the recovery of bred tritium particularly in low temperature region, and increase the tritium molecule form released from the tritium breedin~ materials.
文摘It is urgent to develop excellent solid CO<sub>2</sub> sorbents with higher sorption capacity, simpler synthetic process, better thermal stability and lower costs of synthesis in CO<sub>2</sub> capture and storage technologies. In this work, a number of Li<sub>4</sub>SiO<sub>4</sub>-based sorbents synthesized by lithium carbonate with three different kinds of fly ashes in various molar ratios were developed. The results indicate that the Li<sub>2</sub>CO<sub>3</sub>:SiO<sub>2</sub> mole ratio used in the sorbents synthesis significantly affects the CO<sub>2</sub> absorption properties. The sorption capacity increased with the excess of Li<sub>2</sub>CO<sub>3</sub> first and then decreased when the excessive quantity was beyond a certain amount. The experiments found that FA-Li<sub>4</sub>SiO<sub>4</sub>_0.6, CFA-Li<sub>4</sub>SiO<sub>4</sub>_0.4, HCl/CFA-Li<sub>4</sub>SiO<sub>4</sub>_0.3 presented the best sorption ability among these fly ash derived Li<sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;">SiO</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;"> samples, and the corresponding weight gain was 28.2 wt%, 25.1 wt% and 32.5 wt%, respectively. The three sorbents with the optimal molar ratio were characterized using various morphological </span><span style="font-family:Verdana;">characterization techniques and evaluated by thermogravimetric analysis </span><span style="font-family:Verdana;">for their capacity to chemisorb CO<sub>2</sub> at 450<sup></sup></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;"><span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span></span><span style="font-family:Verdana;"></span><span style="font-family:Verdana;">C</span><span style="font-family:Verdana;"> - 650<sup></sup></span><span style="font-family:Verdana;"><span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°</span></span><span style="font-family:Verdana;"></span><span style="font-family:Verdana;">C</span><span style="font-family:Verdana;">, diluted CO<sub>2</sub> (10%, 20%) and in presence of water vapor (12%). The adsorption curve of FA- Li<sub>4</sub>SiO<sub>4</sub>_0.6 at different temperatures was simulated with the Jander-Zhang model to explore the influence of carbon dioxide diffusion on adsorption reaction. Further experiments showed that the adsorbent had a good sorption capacity in a lower partial pressure of CO<sub>2</sub> and the presence of steam enhanced the mobility of Li<sup>+</sup>. What’s more, FA-Li<sub>4</sub>SiO<sub>4</sub>_0.6, CFA-Li<sub>4</sub>SiO<sub>4</sub>_0.4 and HCl/CFA-Li<sub>4</sub>SiO<sub>4</sub>_0.3 particles showed satisfactory sorption capacity in fixed-bed reactor and excellent cyclic sorption stability during 10 sorption/ desorption cycles.</span></span></span></span>
基金Project(50302016) supported by the National Natural Science Foundation of China
文摘Li2Fe0.9Mn0.1SiO4/C composites were synthesized by using X-ray diffractometry （XRD）, scanning electron microscopy （SEM） glucose as carbon source. The samples were characterized by and electrochemical measurements. All Li2Fe0.9Mn0.1SiO4/C composites are of the similar crystal structure. With increasing the carbon content in the range of 5%-20% （mass fraction）, the diffraction peaks in XRD patterns broaden and the particle sizes and the tap density of samples decrease. The Li2Fe0.9Mn0.1SiO4/C composites with carbon content of 14.12% show excellent electrochemical performances with an initial discharge capacity of 154.7 mA.h/g at C/16 rate, and the capacity retention remains 92.2% after 30 cycles.
