Synthesis and Characterization of Ceramic Membranes (W‐Type Zeolite Membranes)

Abstract

In this article, effects of synthesis parameters (synthesis temperature, synthesis time, and number of layers) on W‐type zeolite membranes synthesized over flat SUS supports for O2/SF6 gas separation were experimentally investigated. Experiments were carried out at these levels of synthesis temperature: 165°C, 185°C, and 200°C; synthesis time: 6, 12, and 18 h and number of layers: 1 and 2. Permeation measurements, XRD and SEM analysis were used for characterization of the synthesized membranes. The results showed that increasing synthesis temperature from 165°C up to 185°C increases separation factor of O2/SF6, however, further increasing decreases the separation performance. The same trend was observed for synthesis time for the single layer synthesized zeolite W membrane, although for the double layer synthesized zeolite W membrane, separation factor increased with increasing synthesis time. Repetition of layering has a net positive effect on separation factor of O2/SF6, and negative effect on permeation flux through the membranes. This behavior was attributed to the dual effect of synthesis temperature and synthesis time on selectivity. More zeolite crystals are deposited and larger crystals are formed at higher synthesis temperatures and longer synthesis times. Well W‐type zeolite membrane was synthesized at 185°C for 18 h with two repeating layers with a high separation factor of 20.1.

The Potential Role of Membrane Technology in the Removal of Microplastics from Wastewater

“…A suitable polymer material for nanofiltration membrane production is expected to resist thermal and chemical attack with outstanding mechanical strength and capacity to form flat-sheet or hollow fiber structure. Apart from the polymeric membranes, studies have also revealed the production of ceramic membranes from alumina, zirconia, silica and oxide mixture [81][82][83][84]. They are preferred to the polymeric membranes because of the existence of lower fouling, narrow pore size distribution, chemical stability and higher porosity in ceramic membranes.…”

Preparation of 13X zeolite powder and membrane: investigation of synthesis parameters impacts using experimental design

“…As crystal growth rate increased, larger crystals in size are formed and integrated faster as the membrane selective layer over the seeded support. Faster crystals integration is obtained in the compensate of lower average zeolite crystals density, i. e., more defective regions such as nonselective cracks or voids are appeared in the faster formed zeolitic membrane layer [40,49].…”

“…The zeolite layer, which determines gas penetration behavior of the membrane, was formed properly at 12 h synthesis time and uniformly covered the support surface resulted in the reduced membrane gas penetration. Meanwhile there were still non zeolitic/amorphous regions kept the membrane's selectivity low [49]. At the synthesis time higher than 12 h, gaseous penetrants permeabilities increase due to increased porosity of the formed zeolite layer as the larger crystals are formed and the selective zeolite layer crystallinity and porosity enhance as well.…”

“…At the zeolite top layer, non-zeolite cavities are covered by larger zeolite crystals, and thus the membranes selectivities enhance and penetrants permeabilities also increase due to the more porous selective layer. Since, higher selectivity of the membrane is favored with its higher permeance, the 16 h synthesis time with high ideal H 2 /CO 2 selectivity and also acceptable penetrants permeances (although it is lower than that of the 8 h synthesized zeolite membrane) was selected as the best membrane synthesis time [49]. Figure 11 indicates synthesis temperature's impact on ideal H 2 /CO 2 selectivities of the zeolite membrane's at various synthesis times.…”

Advances in water treatment by microfiltration, ultrafiltration, and nanofiltration

“…Generally, materials used for ceramic membranes are zirconia, silica, alumina, mullite, oxide mixtures, and sintered metals (Harman, Koseoglu, Yigit, Beyhan, & Kitis, 2010;Hofs, Ogier, Vries, Beerendonk, & Cornelissen, 2011;Mohammadi & Maghsoodloorad, 2013;Pendergast & Hoek, 2011). Typical ceramic membranes are fabricated using the sol-gel process and are asymmetric in structure.…”