Zeolite nanoblock (ZNB), prepared by hydrochloric acid decomposition of Na-A type zeolite, works as a highly efficient hydrogen-permeable membrane. Si and Al K-edge X-ray absorption near edge structure (XANES) spectra were measured for ZNB to clarify the local structures. The Si K-edge XANES spectrum is similar to that of the Na-A type zeolite, but the Al K-edge XANES spectrum is interpreted as...

Zeolite membranes are widely used in separation, catalysis, sensors and other fields because of their good diffusion performance, shape selection catalysis capabilities. However, the slow synthesis rate zeolite restricts industrialization process, random orientation seriously affects performance. Therefore, this paper investigates methods for accelerating zeolites roles different was explored. ...

Benzene alkylation with propylene was studied in the gas phase using a catalytic membrane reactor and a fixed-bed reactor in the temperature range of 200-300 °C and with a weight hourly space velocity (WHSV) of 51 h-1. β-zeolite was prepared by hydrothermal synthesis using silica, aluminum metal and TEAOH as precursors. The membrane's XRD patterns showed good crystallinity for the β-zeolite fil...

Nanopore silicalite type membranes were prepared on the outer surface of a porous-mullite tube by in situ liquid phase hydrothermal synthesis. The hydrothermal crystallization was carried out under an autogenously pressure, at a static condition and temperature of 180 °C with tetrapropylammonium bromide (TPABr) as a template agent. The molar composition of the starting gel of silicalite zeolite...

We report the quantitative, non-destructive determination of the concentration profile of an organic molecule in a nanoporous polycrystalline zeolite molecular sieve membrane, by step scan infra-red photoacoustic experiments and analysis. An important application of stepscan photoacoustic spectroscopy is the transport-model-independent experimental description of membrane transport, by simultan...

A simplified mathematical model is proposed to provide an analytic solution for the transient behavior of a Langmuirian zeolite membrane subjected to a step increase in sorbate pressure at the upstream surface at time zero. The concentration profiles derived from the simplified model agree with those calculated by numerical solution of the governing partial differential equation. The model is u...

A zeolite NaA (A-type zeolite of ca. 0.4 nm pore size; Linde Type A, LTA) membrane for the dehydration of alcohol was characterized by X-ray diffraction analysis (XRD). Also, the relationship between the X-ray absorption and the EtOH/H2O pervaporation (PV) dehydration performance (water selectivity and permeation flux) of the LTA membrane was first investigated. The LTA membranes used here were...

Zeolite membranes are highly attractive in energy efficient, selective separation technologies. Their high selectivity originates from adsorption, diffusion and even molecular sieving. High flux zeolite (> 1 mol s−1m−2) with a sub-micrometer thickness mechanically stabilized by porous, often multilayer, support. Transport mechanisms layer support, however, counteracting regarding selectivity, s...

Molecular sieving MFI-type zeolite membranes were prepared by a secondary growth method without using an organic template. Silicalite membranes with intercrystalline pores minimized or eliminated were obtained by this synthesis method which avoids the template removal step. The silicalite membrane exhibits molecular sieving characteristics with pervaporation separation factor for p-xylene to o-...