A preferentially oriented mordenite membrane was successfully prepared on a seeded porous α-alumina support. Characterization results of XRD (X-ray diffractometer) and FE-SEM (field emission scanning electron microsc...A preferentially oriented mordenite membrane was successfully prepared on a seeded porous α-alumina support. Characterization results of XRD (X-ray diffractometer) and FE-SEM (field emission scanning electron microscope) revealed that evolutionary selection might predominantly contribute to the formation of the sharply oriented mordenite membrane. The nec- essary conditions under which evolutionary selection occurs are: (a) the number density of nuclei on the support surface should be high enough at the early stage; (b) the crystals should grow fastest along one direction; and (c) the zeolite layer should proceed via the successive growth of the crystals nucleated on the support surface instead of the accumulation of the crystals formed in the bulk solution.展开更多
ZSM-35 zeolite membranes were prepared on porous stainless steel tubes with silica sol and tetraethoxysi-lane as silica source,and with 1-butylamine and ethylenedi-amine as templates,respectively.The characterization ...ZSM-35 zeolite membranes were prepared on porous stainless steel tubes with silica sol and tetraethoxysi-lane as silica source,and with 1-butylamine and ethylenedi-amine as templates,respectively.The characterization of X-ray diffraction(XRD)and scanning electron microscopy(SEM)showed that the membranes prepared with ethylene-diamine as the template displayed growth orientation with their crystal planes(h00)parallel to the support surface.The single-component permeability tests of H2,N2 and C3H8 showed that the membranes synthesized with ethylene-diamine as the template,compared with those with 1-butylamine as the template,showed relatively higher permeation rates and ideal separation factors,and above their corresponding ideal Knudsen diffusion factors,which might be attributed to the different growth orientation of zeolite membranes synthesized with different templates.展开更多
The growth and orientation of zeolite crystals on a glass substrate was investigated by changing the roughness and setting of the substrate surface.The orientation control of crystals on the glass substrate was achiev...The growth and orientation of zeolite crystals on a glass substrate was investigated by changing the roughness and setting of the substrate surface.The orientation control of crystals on the glass substrate was achieved.It was found that the setting and treatment of the glass substrate had a substantial effect on crystal orientation.When the substrate surface was upward, the preferential growth of crystal was along the a-axis.However, the preferential growth of crystal was along b-axis when the substrate surface was downward.According to experimental results, a film formation mechanism was proposed to account for the growth and orientation of crystals on the glass substrate.展开更多
Continuous and perfect single-layer B-Al-ZSM-5 zeolite membranes with c-axis orientation, self-transformation from B-containing porous gla ss disks w ith rough and uneven surfaces full of pits, have been in-situ prepa...Continuous and perfect single-layer B-Al-ZSM-5 zeolite membranes with c-axis orientation, self-transformation from B-containing porous gla ss disks w ith rough and uneven surfaces full of pits, have been in-situ prepared on the su bstrates surfaces in a mixed vapor of ethylenediamine, tri-n-propylamine a nd H 2O . The thickness of the membranes is ca. 60 μm. Under the conditions of 20 ℃ and 0.1 MPa pressure difference, the permeabilities of H 2, O 2 and N 2 thro ugh the calcined B-Al-ZSM-5 zeolite membranes are 2 298×10 -8 , 1 176 ×10 -8 and 1 368×10 -9 mol/(m 2·s·Pa), respectively. The calculated values of ideal se lectivities of H 2 an d O 2 over N 2 are 16 8 and 8 60, respectively. The data indicate that the c alcin ed zeolite membranes are non-pinhole, non-crack, continuous and perfect.展开更多
文摘A preferentially oriented mordenite membrane was successfully prepared on a seeded porous α-alumina support. Characterization results of XRD (X-ray diffractometer) and FE-SEM (field emission scanning electron microscope) revealed that evolutionary selection might predominantly contribute to the formation of the sharply oriented mordenite membrane. The nec- essary conditions under which evolutionary selection occurs are: (a) the number density of nuclei on the support surface should be high enough at the early stage; (b) the crystals should grow fastest along one direction; and (c) the zeolite layer should proceed via the successive growth of the crystals nucleated on the support surface instead of the accumulation of the crystals formed in the bulk solution.
基金supported by the National Natural Science Foundation of China(Grant No.20176004).
文摘ZSM-35 zeolite membranes were prepared on porous stainless steel tubes with silica sol and tetraethoxysi-lane as silica source,and with 1-butylamine and ethylenedi-amine as templates,respectively.The characterization of X-ray diffraction(XRD)and scanning electron microscopy(SEM)showed that the membranes prepared with ethylene-diamine as the template displayed growth orientation with their crystal planes(h00)parallel to the support surface.The single-component permeability tests of H2,N2 and C3H8 showed that the membranes synthesized with ethylene-diamine as the template,compared with those with 1-butylamine as the template,showed relatively higher permeation rates and ideal separation factors,and above their corresponding ideal Knudsen diffusion factors,which might be attributed to the different growth orientation of zeolite membranes synthesized with different templates.
文摘The growth and orientation of zeolite crystals on a glass substrate was investigated by changing the roughness and setting of the substrate surface.The orientation control of crystals on the glass substrate was achieved.It was found that the setting and treatment of the glass substrate had a substantial effect on crystal orientation.When the substrate surface was upward, the preferential growth of crystal was along the a-axis.However, the preferential growth of crystal was along b-axis when the substrate surface was downward.According to experimental results, a film formation mechanism was proposed to account for the growth and orientation of crystals on the glass substrate.
文摘Continuous and perfect single-layer B-Al-ZSM-5 zeolite membranes with c-axis orientation, self-transformation from B-containing porous gla ss disks w ith rough and uneven surfaces full of pits, have been in-situ prepared on the su bstrates surfaces in a mixed vapor of ethylenediamine, tri-n-propylamine a nd H 2O . The thickness of the membranes is ca. 60 μm. Under the conditions of 20 ℃ and 0.1 MPa pressure difference, the permeabilities of H 2, O 2 and N 2 thro ugh the calcined B-Al-ZSM-5 zeolite membranes are 2 298×10 -8 , 1 176 ×10 -8 and 1 368×10 -9 mol/(m 2·s·Pa), respectively. The calculated values of ideal se lectivities of H 2 an d O 2 over N 2 are 16 8 and 8 60, respectively. The data indicate that the c alcin ed zeolite membranes are non-pinhole, non-crack, continuous and perfect.
