Synthesis of highly c-oriented ZIF-69 membranes by secondary growth and their gas permeation properties
KAUST DepartmentAdvanced Membranes and Porous Materials Research Center
Biological and Environmental Sciences and Engineering (BESE) Division
Physical Sciences and Engineering (PSE) Division
Chemical and Biological Engineering Program
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AbstractA seeded growth procedure was successfully developed to synthesize highly c-oriented and well-intergrown zeolitic imidazolate framework-69 (ZIF-69) membranes on porous α-alumina substrates. The synthesis conditions were optimized both for seed preparation and for secondary growth. For seeding, a facile method was developed to prepare smaller and flat ZIF-69 microcrystals in order to make thin and c-oriented seed layers. While for secondary growth, a synthesis condition that favored the growth along the c-direction was chosen in order to form highly c-oriented ZIF-69 membranes after growth. As a result, the majority of ZIF-69 grains inside the membrane have their straight channels along the crystallographic c-axis aligned perpendicularly to the substrate surface. Such alignment was confirmed by both XRD and pole figure analysis. The mixture-gas separation studies that were carried out at room temperature and 1atm gave separation factors of 6.3, 5.0, 4.6 for CO2/N2, CO2/CO and CO2/CH4 respectively, and a permeance of ∼1.0×10-7molm-2s-1Pa-1 for CO2 in almost all mixtures. Both the separation factor and permeance were better than the performance of the ZIF-69 membranes prepared by the in situ solvothermal method due to improvement in the membrane microstructure by the seeded growth method. © 2011 Elsevier B.V.
SponsorsWe acknowledge the financial support from KAUST distribution fund 31500/4000000066.
JournalJournal of Membrane Science