To deal with the brittleness and crystal grain interfacial defects of zeolite membranes, and to confine the pore size distribution of inorganic membranes in a limited range, a process method for composite membranes of...To deal with the brittleness and crystal grain interfacial defects of zeolite membranes, and to confine the pore size distribution of inorganic membranes in a limited range, a process method for composite membranes of A-type zeolite/SiO 2 was discribed. A silica sol was mixed with nanocrystals of zeolite 4A in a suitable proportion, then the supported membranes was prepared by dip-coating method. The composite membranes prepared in first step was treated hydrothermally again, so nanocrystal zeolite 4A formed and located in the mesopores of the membranes, and the microstructure and pore size distribution of the membrane were modified greatly. The thermal stability, mineral phase, microstructure, and pore size distribution were examined via DTA-TG, X-ray diffractometer, scanning electron microscope (SEM), and BET equipment. The structure of the composite membranes remains high stability below 800 ℃. Its average pore size in a very limited range is smaller than that in the untreated membranes in hydrothermal condition, and the peak bands of the membrane pores are 4×10 -10 m, 1.8×10 -9 m, respectively.展开更多
High-quality standard oil synthetic zeolite-13(SSZ-13) membranes with thickness only ~ 1.0 μm were prepared on tubular supports by the new seeded-gel approach. Seeded-gel approach is simpler than the normal secondary...High-quality standard oil synthetic zeolite-13(SSZ-13) membranes with thickness only ~ 1.0 μm were prepared on tubular supports by the new seeded-gel approach. Seeded-gel approach is simpler than the normal secondary-growth one since adding seeds in the gel is simpler than seeding on the support surface. The synthesis time was greatly reduced from 3.0 to 1.0 d after synthesis modification of gel aging and seed sizes. Low temperature ozone calcination was used for the removal of the organic structural directing agent. The best SSZ-13 membrane displayed CO_(2)permeances of 1.3 × 10^(-6) and 1.5 × 10^(-6) mol·m^(-2)·s^(-1)·Pa^(-1) and CO_(2)/CH_(4) and CO_(2)/N_(2) selectivities of 125 and 27 for equimolar CO_(2)/CH_(4) and CO_(2)/N2mixtures at 0.2 MPa pressure drop and 298 K, respectively. Separation performance of the membrane in the two binary mixtures is higher than that of most zeolite membranes. Three SSZ-13 membranes were reproducibly prepared on tubular supports by seeded-gel approach and the standard deviation ratios of CO_(2) permeance and CO_(2)/CH_(4) selectivity are 12.5% and 7%, respectively. It suggests that this new synthesis approach is creditable. The effects of temperature and pressure on separation performance of the thin SSZ-13 membranes were studied in the two binary mixtures. The tubular SSZ-13 membranes displayed great potentials for CO_(2) capture from natural gas, biogas and flue gas.展开更多
Layered assembled membranes of 2D leaf-like zeolitic imidazolate frameworks(ZIF-L)nanosheets have received great attention in the field of water treatment due to the porous structure and excellent antibacterial abilit...Layered assembled membranes of 2D leaf-like zeolitic imidazolate frameworks(ZIF-L)nanosheets have received great attention in the field of water treatment due to the porous structure and excellent antibacterial ability,but the dense accumulation on the membrane surface and the low permeate flux greatly hinder their application.Herein,we synthesized m HNTs(modified halloysite nanotubes)/ZIF-L nanocomposites on modified m HNTs by in situ growth method.Interestingly,due to the different size of m HNTs and ZIF-L,m HNTs were packed in ZIF-L nanosheets.The hollow m HNTs provided additional transport channels for water molecules,and the accumulation of the ZIF-L nanosheets was decreased after assembling m HNTs/ZIF-L nanocomposites into membrane by filtration.The prepared m HNTs/ZIF-L membrane presented high permeate flux(59.6 L·m^(-2)·h^(-1)),which is 2-4 times of the ZIF-L membranes(14.8 L·m^(-2)·h^(-1)).Moreover,m HNTs/ZIF-L membranes are intrinsically antimicrobial,which exhibit extremely high bacterial resistance.We provide a controllable strategy to improve 2D ZIF-L assembles,and develops novel membranes using 2D package structure as building units.展开更多
For the first time the preparation of the N-doped TiO2-coated NaY zeolite membrane（N-doped TiO2/NaY zeolite membrane） as an electrode material for photoelectrocatalysis has been achieved and reported.The XRD, SEM, U...For the first time the preparation of the N-doped TiO2-coated NaY zeolite membrane（N-doped TiO2/NaY zeolite membrane） as an electrode material for photoelectrocatalysis has been achieved and reported.The XRD, SEM, UV–vis and XPS techniques were used to characterize the structure of the N-doped TiO2/NaY zeolite membrane. The results verified that the surface of the N-doped TiO2/NaY zeolite membrane was coated by TiO2 nanoparticles of ca. 20 nm size and exhibited a distinct red-shift in the UV–vis spectra compared to N-doped TiO2. The photoelectrocatalysis performance of the N-doped TiO2/NaY zeolite membrane electrode was evaluated by phenol degradation. The results revealed it is a promising novel electrode material for application of photoelectrocatalysis in the removal of organic contaminants in waste water.展开更多
文摘To deal with the brittleness and crystal grain interfacial defects of zeolite membranes, and to confine the pore size distribution of inorganic membranes in a limited range, a process method for composite membranes of A-type zeolite/SiO 2 was discribed. A silica sol was mixed with nanocrystals of zeolite 4A in a suitable proportion, then the supported membranes was prepared by dip-coating method. The composite membranes prepared in first step was treated hydrothermally again, so nanocrystal zeolite 4A formed and located in the mesopores of the membranes, and the microstructure and pore size distribution of the membrane were modified greatly. The thermal stability, mineral phase, microstructure, and pore size distribution were examined via DTA-TG, X-ray diffractometer, scanning electron microscope (SEM), and BET equipment. The structure of the composite membranes remains high stability below 800 ℃. Its average pore size in a very limited range is smaller than that in the untreated membranes in hydrothermal condition, and the peak bands of the membrane pores are 4×10 -10 m, 1.8×10 -9 m, respectively.
基金Financial supports from the National Natural Science Foundation of China (21921006, 21938007 and 21576131)the open project of the State Key Laboratory of Materials-Oriented Chemical Engineering of China (KL21-04)。
文摘High-quality standard oil synthetic zeolite-13(SSZ-13) membranes with thickness only ~ 1.0 μm were prepared on tubular supports by the new seeded-gel approach. Seeded-gel approach is simpler than the normal secondary-growth one since adding seeds in the gel is simpler than seeding on the support surface. The synthesis time was greatly reduced from 3.0 to 1.0 d after synthesis modification of gel aging and seed sizes. Low temperature ozone calcination was used for the removal of the organic structural directing agent. The best SSZ-13 membrane displayed CO_(2)permeances of 1.3 × 10^(-6) and 1.5 × 10^(-6) mol·m^(-2)·s^(-1)·Pa^(-1) and CO_(2)/CH_(4) and CO_(2)/N_(2) selectivities of 125 and 27 for equimolar CO_(2)/CH_(4) and CO_(2)/N2mixtures at 0.2 MPa pressure drop and 298 K, respectively. Separation performance of the membrane in the two binary mixtures is higher than that of most zeolite membranes. Three SSZ-13 membranes were reproducibly prepared on tubular supports by seeded-gel approach and the standard deviation ratios of CO_(2) permeance and CO_(2)/CH_(4) selectivity are 12.5% and 7%, respectively. It suggests that this new synthesis approach is creditable. The effects of temperature and pressure on separation performance of the thin SSZ-13 membranes were studied in the two binary mixtures. The tubular SSZ-13 membranes displayed great potentials for CO_(2) capture from natural gas, biogas and flue gas.
基金supported by the Excellent Youth Foundation of Henan Scientific Committee,China(222300420018)Key Scientific Research Projects in Universities of Henan Province,China(21zx006)。
文摘Layered assembled membranes of 2D leaf-like zeolitic imidazolate frameworks(ZIF-L)nanosheets have received great attention in the field of water treatment due to the porous structure and excellent antibacterial ability,but the dense accumulation on the membrane surface and the low permeate flux greatly hinder their application.Herein,we synthesized m HNTs(modified halloysite nanotubes)/ZIF-L nanocomposites on modified m HNTs by in situ growth method.Interestingly,due to the different size of m HNTs and ZIF-L,m HNTs were packed in ZIF-L nanosheets.The hollow m HNTs provided additional transport channels for water molecules,and the accumulation of the ZIF-L nanosheets was decreased after assembling m HNTs/ZIF-L nanocomposites into membrane by filtration.The prepared m HNTs/ZIF-L membrane presented high permeate flux(59.6 L·m^(-2)·h^(-1)),which is 2-4 times of the ZIF-L membranes(14.8 L·m^(-2)·h^(-1)).Moreover,m HNTs/ZIF-L membranes are intrinsically antimicrobial,which exhibit extremely high bacterial resistance.We provide a controllable strategy to improve 2D ZIF-L assembles,and develops novel membranes using 2D package structure as building units.
基金supported by the Talent Introduction Fund of Yangzhou University(2012),Jiangsu Province Science and Technology Support Project(No.BE2014613)Six Big Peak Talent in Jiangsu Province(No.2014-XCL-013)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘For the first time the preparation of the N-doped TiO2-coated NaY zeolite membrane（N-doped TiO2/NaY zeolite membrane） as an electrode material for photoelectrocatalysis has been achieved and reported.The XRD, SEM, UV–vis and XPS techniques were used to characterize the structure of the N-doped TiO2/NaY zeolite membrane. The results verified that the surface of the N-doped TiO2/NaY zeolite membrane was coated by TiO2 nanoparticles of ca. 20 nm size and exhibited a distinct red-shift in the UV–vis spectra compared to N-doped TiO2. The photoelectrocatalysis performance of the N-doped TiO2/NaY zeolite membrane electrode was evaluated by phenol degradation. The results revealed it is a promising novel electrode material for application of photoelectrocatalysis in the removal of organic contaminants in waste water.
