Synthesis of Thin, Oriented Zeolite A Membranes on a Macroporous Support

Abstract

Continuous, thin, oriented zeolite A membranes are produced by a two‐step synthesis on macroporous α‐Al2O3 supports. In the first step, zeolite A nano‐cubes with ∼350‐nm edges are prepared as a native impurity phase in zeolite Y synthesis dispersions, the support surface is pre‐modified with a cationic polymer having a selective affinity for zeolite A. The thus‐treated support is contacted with a colloidally stable dispersion of zeolite A and Y mixture in water, which results in selective, dense‐packed deposition of the zeolite A cubes with one face aligned to the average support surface. In a second step of hydrothermal epitaxial growth, the seed layer grows epitaxially into a continuous, meso‐defect free, ∼1 µm thick zeolite A layer, already after 1 h of treatment. This microstructure of the membrane compares very favorably to what is commonly obtained. The pH value of the zeolite mixture suspension is found to have a major influence on seed layer morphology, and thereby, on the quality and orientation of zeolite A membrane after short synthesis times. The final zeolite A membrane thickness and morphology is controlled by varying secondary growth synthesis time. The approach presented is thought to be of generic use for the preparation of oriented zeolite membranes.

Kinetic and isotherm insights of Diclofenac removal by sludge derived hydrochar

“…FTIR (Shimadzu’s 8400S model) was used to detect the molecular functionalities prevailing in the hydrochar at 400–4000 cm −1 wavenumber range 29 . Horiba Scientific Nanopartica SZ-100 particle size analyzer was used to analyze the zeta potential of hydrochars 30 . FEI—Quanta 250 Scanning Electron Microscope (SEM) was used to examine the structural morphologies of hydrochars at a voltage of 8 kV with × 10,000 magnification.…”

Synthesis of Ultrathin Zeolite Y Membranes and their Application for Separation of Carbon Dioxide and Nitrogen Gases

“…Transport measurements were carried out for CO 2 and N 2 and their mixtures, and the separation properties were correlated with the membrane characteristics. Though there have been reports for synthesis of ultrathin zeolite A and MFI membranes and a permporometry study, , the present report is the first to synthesize ultrathin zeolite Y membranes and study their CO 2 /N 2 gas separation characteristics.…”

Preparation and Characterization of Optimized Hydrochar from Paper Board Mill Sludge

“…The functional groups were determined using FTIR (Model 8400 S of Shimadzu, Japan) over the wavenumber range of 400-4000 cm −1 11 . The particle size and zeta potential were measured using the particle size analyzer, Horiba Scientific Nanopartica SZ-100, Japan 12 .…”