(600c) Stability and Separation Performance of Highly c-Oriented AFI-Type Aluminophosphate Membranes

Continuous,
highly c-oriented aluminophosphate films
(structure code AFI) were grown on porous α-Al₂O₃
supports in order to investigate their potential for molecular separation
applications.  Variations in metal
substitution (AlPO₄-5, CoAPO-5, CoSAPO-5), growth method (forced air
convection oven, microwave), and calcination technique (conventional, rapid
thermal processing) were chosen to examine the conditions by which membrane
quality was optimized.  Following
hydrothermal growth in a forced air convection oven, AlPO₄-5 and
CoAPO-5 membranes underwent densification to an AlPO-tridymite
phase following heat treatment, resulting in reduced membrane functionality
which may be partially avoided through the use of rapid thermal processing. On
the other hand, membranes prepared by an optimized method were found to be
thermally stable with high membrane quality as inspected through pervaporation
measurements consisting of a liquid hydrocarbon feed of n-heptane
and 1,3,5-triisopropylbenzene.  We will discuss the new aspects that
allowed fabrication of oriented, continuous, high-quality aluminophosphate
membranes and we will provide useful insight into their potential for
applications such as molecular separations, catalysis, or host-guest
assemblies.