第30卷第5期 2015年5月
Article ID: 1000-324X(2015)05-0555-06
无机材料学报 Journal of Inorganic Materials
Vol. 30 No. 5 May,2015
DOI: 10.15541/jim20140566
PreparationofPerfectiveTAPO-5MembranethroughTertiary
GrowthwithAmorphousSeed
LIU Xu-Guang', MA Xin', LIU Yong', ZHANG Bao-Quan'2
(1. College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042, China; 2. State ee China)
Abstract: TAPO-5 membranes were synthesized through a tertiary growth method. Its perfection significantly depends on the adopted seed and itself poly-crystalline structure. Amorphous seed synthesized at a low crystallization tempera-ture (393 K), obviously favors producing the perfective TAPO-5 membrane. TAPO-5 crystal seed, however, induces the growth of its membrane with a larger extent of cracks (i.e., grain boundary defect), destructing itself perfection Those diverse results are associated with the disparate seeds layers deposited by a spreading-wetting method, and consistently demonstrated by SEM, XRD, and single gas (He) permeation test. A typical feature of the amorphous TAPO-5 seed layer is its dispersive distribution pattern in the macro holes of support. A continuous layer, however, is observed for the TAPO-5 crystal seed layer. The amorphous seed is explained as a prior seed for the perfective TAPO-5 membrane.
Key words: tertiary growth; amorphous seed; TAPO-5 membrane; spreading-wetting method
Aluminophosphate molecular sieves (AlPO-n), where n denotes a particular structure type, have been recognized as a novel ordered microporous materialsl'). Their AIPO4 frameworks are rich of structural chemistry and special physiochemical properties of isomorphous substitution by
heteroatoms[2]
metal-aluminophosphateMAPO-n
like
(M = Ti, Fe, etc)[3]. This enables them with excellent
catalytic and separation
porated
AFI
(TAPO-5, oxidation centers
particular ir separatie
brane cracks[6] tants/feeds
taining
ahiol
adopting it as the
pert
aluminophosphat exhibits
ror
pican
.Tiincor-
lolecularsieve
ofselective
edo
active
aal5
isof
ossible applicati will lead to
OUePOSoNARe
Lalit
TAPO-5membra
catalytic mem
oinholeand
of reac ctivities. Ob-e is critical to
catalytic/separationmembrane
Available methods for preparing zeolite membranes in-clude in-situ growth'7], seeded growthl], and dry gel syn-thesis[9], Among those methods, the seeded growth is widely used to prepare zeolite membranes, e.g-, AFi[0), CHA(l), and LTA(12), because of its preferable reproduci-bilityl13], The quality of the membranes prepared by the
seeded growth method is considerably affected by the seeding methods, including dip-coatingl4], rubbingl15] vacuum seedingl16, and filtration seedingl17]. Among these methods, the dip-coating method is easy to perform and generally adopted. The adopted seeds is paid few atten-tions. It depends on the crystalline nature of the seeds.
crystals are popularly employed in the
Nano-sized
seeded growth. Amorphous seeds with a semi-crystal nature exhibits diverse induction behavior during the seed growth. This work will demonstrate that the amor-phous seed is superior to the crystal seed in inducing the growth of the perfective TAPO-5 membrane. The as-synthesized TAPO- 5 membrane is activated by a mild method of catalytic hydrocrackingf18]. Its template is hy-drocracked to small molecules, its perfect structure being maintained.
Experiments 1.1Materials
Phosphoric acid (H,PO4, 85wt%),pseudoboehmite(AlO3, 67wt%, Aluminum Corporation of China, Ltd, Shandong Branch), and TiOSO were used as sources for phosphorus, aluminum, and titanium, respectively. Triethyl-amine (abbreviated as TEA) was chosen as the template
Received date: 2014-11-06; Modified date: 2014-12-03; Published online: 2015-01-10
Foundation item: National Natural Science Foundation of China (21136008); National Ocean Public Project of China (201405008) Biography: LIU Xu-Guang(1983), male, associate professor. E-mail: liuxuguang@qust.edu.cn