Xenon/krypton(Xe/Kr)separation is an important task in industry,yet it remains challenging to develop adsorbents with high Xe/Kr selectivity and adsorption capacity of Xe,especially at low partial pressures.Herein,we ...Xenon/krypton(Xe/Kr)separation is an important task in industry,yet it remains challenging to develop adsorbents with high Xe/Kr selectivity and adsorption capacity of Xe,especially at low partial pressures.Herein,we report a series of microporous carbon molecular sieves(CMSs)for Xe/Kr separation.Those materials have ideal bimodal pore size distributions that not only provide substantial space for the accommodation of gas molecules,but also allow selective diffusion of gas molecules.Additionally,the carbon frameworks decorated with polar oxygen-containing functional groups afford higher affinity for Xe than Kr,which is proven by density functional theory(DFT)calculations and charge density difference analysis.The optimal CPVDC-700 exhibits a high selectivity of Xe/Kr and,more importantly,a record-high uptake of Xe(2.93 mmol g^(-1))at 0.2 bar and298 K,which is the highest among all the reported carbon adsorbents.Breakthrough experiments confirm the excellent performance of such CMSs for Xe/Kr separation,and the dynamic adsorption uptake of Xe and productivity of high-purity Kr are calculated to be 2.91 mmol g^(-1)and 208 m L g^(-1)(9.29 mmol g^(-1)),respectively,which also set up a new benchmark for Xe/Kr separation of carbon adsorbents.展开更多
Membrane separation is an enviroranental benign technology for 21st century, and is developing quickly to replace the conventional distillation process. Carbon raolecular sieve membrane (CMSM) was synthesized through ...Membrane separation is an enviroranental benign technology for 21st century, and is developing quickly to replace the conventional distillation process. Carbon raolecular sieve membrane (CMSM) was synthesized through the contndled pyrolysis of polyimide films. The CMSM is synanetric in structure and presents strong sieving effect towards gas molecules of slightly different diameters. The microstructure of CMSM was manipulated through the thermal treatment program and further modified through activation vapor/chemical depositions. It is demonstrated that CMSM can be synthesized/modified for specific gas mixtures, such as O2/N2, CO2/CH4, C3H6/C3H8, and ect. The pore size distrilmfion, relationship between the permeance & selectivity on CMSM for the separation d some gas pairs was also investigated.展开更多
Hydrogen is a green clean fuel and chemical feedstock. Its separation and purification from hydrogencontaining mixtures is the key step in the production of hydrogen with high purity(>99.99%). In this work, carbon ...Hydrogen is a green clean fuel and chemical feedstock. Its separation and purification from hydrogencontaining mixtures is the key step in the production of hydrogen with high purity(>99.99%). In this work, carbon molecular sieve(CMS) membranes with ultrahigh permselectivity for hydrogen purification were fabricated by high-temperature(700–900 ℃) pyrolysis of polymeric precursor of phenolphthaleinbased cardo poly(arylene ether ketone)(PEK-C). The evolution of the microstructural texture and ultramicroporous structure and gas separation performance of the CMS membrane were characterized via TG-MS, FT-IR, XRD, TEM, CO2 sorption analysis and gas permeation measurements. CMS membranes prepared at 700 ℃ exhibited amorphous turbostratic carbon structures and high H2 permeability of 5260 Barrer with H2/CH4, H2/N2 and H2/CO selectivities of 311, 142, 75, respectively. When carbonized at900 ℃, the CMS membrane with ultrahigh H2/CH4 selectivity of 1859 was derived owing to the formation of the dense and ordered carbon structure. CMS membranes with ultrahigh permselectivity exhibit an attractive application prospect in hydrogen purification.展开更多
基金supported by the National Natural Science Foundation of China(21878260,21978254,22141001)the Ministry of Education-Singapore(MOE2018-T2-2-148,MOE2019-T2-1-093)+4 种基金the Energy Market Authority of Singapore(EMA-EP009-SEGC-020)the Agency for ScienceTechnology and Research(U2102d2004,U2102d2012)the National Research Foundation(NRF-CRP26-2021RS-0002)the China Scholarship Council(CSC,202106310172)for a fellowship to support his study at National University of Singapore。
文摘Xenon/krypton(Xe/Kr)separation is an important task in industry,yet it remains challenging to develop adsorbents with high Xe/Kr selectivity and adsorption capacity of Xe,especially at low partial pressures.Herein,we report a series of microporous carbon molecular sieves(CMSs)for Xe/Kr separation.Those materials have ideal bimodal pore size distributions that not only provide substantial space for the accommodation of gas molecules,but also allow selective diffusion of gas molecules.Additionally,the carbon frameworks decorated with polar oxygen-containing functional groups afford higher affinity for Xe than Kr,which is proven by density functional theory(DFT)calculations and charge density difference analysis.The optimal CPVDC-700 exhibits a high selectivity of Xe/Kr and,more importantly,a record-high uptake of Xe(2.93 mmol g^(-1))at 0.2 bar and298 K,which is the highest among all the reported carbon adsorbents.Breakthrough experiments confirm the excellent performance of such CMSs for Xe/Kr separation,and the dynamic adsorption uptake of Xe and productivity of high-purity Kr are calculated to be 2.91 mmol g^(-1)and 208 m L g^(-1)(9.29 mmol g^(-1)),respectively,which also set up a new benchmark for Xe/Kr separation of carbon adsorbents.
文摘Membrane separation is an enviroranental benign technology for 21st century, and is developing quickly to replace the conventional distillation process. Carbon raolecular sieve membrane (CMSM) was synthesized through the contndled pyrolysis of polyimide films. The CMSM is synanetric in structure and presents strong sieving effect towards gas molecules of slightly different diameters. The microstructure of CMSM was manipulated through the thermal treatment program and further modified through activation vapor/chemical depositions. It is demonstrated that CMSM can be synthesized/modified for specific gas mixtures, such as O2/N2, CO2/CH4, C3H6/C3H8, and ect. The pore size distrilmfion, relationship between the permeance & selectivity on CMSM for the separation d some gas pairs was also investigated.
基金the National Key R&D Program of China(2017YFB0603403)National Natural Science Foundation of China(21676044,21878033,21978034)+1 种基金High Level Innovation Team of Liaoning Province(XLYC1908033)Fundamental Research Funds for the Central Universities(DUT19ZD211,DUT 2018TB02)for the financial support。
文摘Hydrogen is a green clean fuel and chemical feedstock. Its separation and purification from hydrogencontaining mixtures is the key step in the production of hydrogen with high purity(>99.99%). In this work, carbon molecular sieve(CMS) membranes with ultrahigh permselectivity for hydrogen purification were fabricated by high-temperature(700–900 ℃) pyrolysis of polymeric precursor of phenolphthaleinbased cardo poly(arylene ether ketone)(PEK-C). The evolution of the microstructural texture and ultramicroporous structure and gas separation performance of the CMS membrane were characterized via TG-MS, FT-IR, XRD, TEM, CO2 sorption analysis and gas permeation measurements. CMS membranes prepared at 700 ℃ exhibited amorphous turbostratic carbon structures and high H2 permeability of 5260 Barrer with H2/CH4, H2/N2 and H2/CO selectivities of 311, 142, 75, respectively. When carbonized at900 ℃, the CMS membrane with ultrahigh H2/CH4 selectivity of 1859 was derived owing to the formation of the dense and ordered carbon structure. CMS membranes with ultrahigh permselectivity exhibit an attractive application prospect in hydrogen purification.