The objective of this work is to study the influences of silica supports and PEG additive on the sorption performance of molecular basket sorbent（MBS） for COcapture consisting of polyethylenimine and one of the foll...The objective of this work is to study the influences of silica supports and PEG additive on the sorption performance of molecular basket sorbent（MBS） for COcapture consisting of polyethylenimine and one of the following supports: SBA-15（2-D structure）, TUD-1（3-D sponge-like structure） and fumed silica HS-5（3-D disordered structure）. Effects of the supports regarding pore structures and pore properties, the PEI loading amount as well as the sorption temperature were examined. Furthermore, polyethylene glycol（PEG） was introduced as an additive into the sorbents and its effect was investigated at different PEI loadings and sorption temperatures. The results suggest that the pore properties of MBS（after PEI loading） play a more important role in the COsorption capacity, rather than those of the supports alone.MBS with 3D pore structure exhibits higher COsorption capacity and amine efficiency than those with 2D-structured support. Among the sorbents studied, fumed silica（HS-5） based MBS showed the highest COsorption capacity in the temperature range of 30-95 °C, probably due to its unique interstitial pores formed by the aggregation of polymer-loaded SiOparticles. It was found that the temperature dependence is directly related to the PEI surface coverage layers. The more PEI surface coverage layers, the higher diffusion barrier for COand the stronger temperature dependence of COcapacity. 3D MBS exceeds 2D MBS at the same PEI coverage layers due to lower diffusion barrier. Adding PEG can significantly enhance the COsorption capacity and improve amine efficiency of all MBS, most likely by alleviating the diffusion barrier within PEI bulk layers through the inter-molecular interaction between PEI and PEG.展开更多
A series of Al2O3 and CeO2 modified MgO sorbents was prepared and studied for CO2 sorption at moderate temperatures. The CO2 sorption capacity of MgO was enhanced with the addition of either Al2O3 or CeO2. Over Al2O3-...A series of Al2O3 and CeO2 modified MgO sorbents was prepared and studied for CO2 sorption at moderate temperatures. The CO2 sorption capacity of MgO was enhanced with the addition of either Al2O3 or CeO2. Over Al2O3-MgO sorbents, the best capacity of 24.6 mg- CO2/g-sorbent was attained at 100 ℃, which was 61% higher than that of MgO （15.3 mg-CO2/g-sorbent）. The highest capacity of 35.3 mg-CO2/g-sorbent was obtained over the CeO2-MgO sorbents at the optimal temperature of 200 ℃. Combining with the characterization results, we conclude that the promotion effect on CO2 sorption with the addition of Al2O3 and CeO2 can be attributed to the increased surface area with reduced MgO crystallite size. Moreover, the addition of CeO2 increased the basicity of MgO phase, resulting in more increase in the CO2 capacity than Al2O3 promoter. Both the Al2O3-MgO and CeO2- MgO sorbents exhibited better cyclic stability than MgO over the course of fifteen CO2 sorption-desorption cycles. Compared to Al2O3, CeO2 is more effective for promoting the CO2 capacity of MgO. To enhance the CO2 capacity of MgO sorbent, increasing the basicity is more effective than the increase in the surface area.展开更多
基金the support of this work at Penn State by the U.S.Department of Energy,National Energy Technology Laboratorythe financial support by the China Scholarship Council,the Natural Science Foundation of China(No.51176034)the Open Fund of Key Laboratory of Coal-Based CO2 Capture and Geological Storage of Jiangsu Province(2016A05)
文摘The objective of this work is to study the influences of silica supports and PEG additive on the sorption performance of molecular basket sorbent（MBS） for COcapture consisting of polyethylenimine and one of the following supports: SBA-15（2-D structure）, TUD-1（3-D sponge-like structure） and fumed silica HS-5（3-D disordered structure）. Effects of the supports regarding pore structures and pore properties, the PEI loading amount as well as the sorption temperature were examined. Furthermore, polyethylene glycol（PEG） was introduced as an additive into the sorbents and its effect was investigated at different PEI loadings and sorption temperatures. The results suggest that the pore properties of MBS（after PEI loading） play a more important role in the COsorption capacity, rather than those of the supports alone.MBS with 3D pore structure exhibits higher COsorption capacity and amine efficiency than those with 2D-structured support. Among the sorbents studied, fumed silica（HS-5） based MBS showed the highest COsorption capacity in the temperature range of 30-95 °C, probably due to its unique interstitial pores formed by the aggregation of polymer-loaded SiOparticles. It was found that the temperature dependence is directly related to the PEI surface coverage layers. The more PEI surface coverage layers, the higher diffusion barrier for COand the stronger temperature dependence of COcapacity. 3D MBS exceeds 2D MBS at the same PEI coverage layers due to lower diffusion barrier. Adding PEG can significantly enhance the COsorption capacity and improve amine efficiency of all MBS, most likely by alleviating the diffusion barrier within PEI bulk layers through the inter-molecular interaction between PEI and PEG.
基金Acknowledgements The authors gratefully acknowledge the financial support from Pennsylvania State University through the Penn State Institutes of Energy and the Environment, and from the National Natural Science Foundation of China （Grant No. 21005083） and the Innovative Fund of Shanghai Institute of Ceramics, Chinese Academy of Sciences （Grant No. Y37ZC4140G）. Dr. Huimei Yu would like to thank the Chinese Academy of Sciences for the visiting scholarship and Dr. Song for the visiting scholar invitation to the EMS Energy Institute at Penn State.
文摘A series of Al2O3 and CeO2 modified MgO sorbents was prepared and studied for CO2 sorption at moderate temperatures. The CO2 sorption capacity of MgO was enhanced with the addition of either Al2O3 or CeO2. Over Al2O3-MgO sorbents, the best capacity of 24.6 mg- CO2/g-sorbent was attained at 100 ℃, which was 61% higher than that of MgO （15.3 mg-CO2/g-sorbent）. The highest capacity of 35.3 mg-CO2/g-sorbent was obtained over the CeO2-MgO sorbents at the optimal temperature of 200 ℃. Combining with the characterization results, we conclude that the promotion effect on CO2 sorption with the addition of Al2O3 and CeO2 can be attributed to the increased surface area with reduced MgO crystallite size. Moreover, the addition of CeO2 increased the basicity of MgO phase, resulting in more increase in the CO2 capacity than Al2O3 promoter. Both the Al2O3-MgO and CeO2- MgO sorbents exhibited better cyclic stability than MgO over the course of fifteen CO2 sorption-desorption cycles. Compared to Al2O3, CeO2 is more effective for promoting the CO2 capacity of MgO. To enhance the CO2 capacity of MgO sorbent, increasing the basicity is more effective than the increase in the surface area.
