Pervaporation of ethanol/water mixtures by zeolite A membranes synthesized in batch and flow systems

Download
2011
Arıcan Yüksel, Berna
Zeolite A membranes have great potential in pervaporation separation of ethanol/water mixtures with high flux and selectivity. Zeolite membranes usually synthesized from hydrogels in batch systems. In recent years, zeolite membranes are prepared in semicontinuous, continuous and recirculating flow systems to allow the synthesis of zeolite membranes with enlarged surface areas and to overcome the limitations of batch system at industrial level production. The purpose of this study is to develop a synthesis method for the preparation of good quality zeolite A membranes in a recirculated flow system from hydrogels and to test the separation performance of the synthesized membranes by pervaporation of ethanol/water mixture. In this context, three different experimental synthesis parameters were investigated with zeolite A membranes synthesized in batch system. These parameters were the composition of the starting synthesis hydrogel, silica source and the seeding technique. Syntheses were carried out using hydrogels at atmospheric pressure and at 95 °C. The membranes were characterized by X-ray diffraction, scanning electron microscopy and pervaporation of 90 wt% ethanol-10 wt% water mixtures. v Pure zeolite A membranes were synthesized both in batch and flow systems. The membranes synthesized in batch system have fluxes around 0.2-0.3 kg/m2h and selectivities in the range of 10-100. Membranes with higher selectivities were obtained in batch system by using waterglass as silica source, seeding by dip-coating wiping method, and with a batch composition of 3.4Na2O:Al2O3:2SiO2:155H2O. The membranes prepared in flow system have higher pervaporation performances than the ones prepared in batch system in considering both flux and the selectivity. Fluxes were around 0.3-3.7 kg/m2h and selectivities were in the range of 102-104 for the membranes prepared in flow system which are comparable with the data reported in literature for batch and flow systems. A high quality zeolite A membrane was also synthesized from 3.4Na2O:Al2O3:2SiO2:200H2O hydrogel at 95 °C for 17 hours in flow system. Pervaporation flux of this membrane was 1.2 kg/m2h with a selectivity >25,000 at 50°C. Although the synthesis method is resulted with high quality membrane, reproducibility of the synthesis method is poor and it should be improved.

Suggestions

Pervaporation of organic/water mixtures by MFI type zeolite membranes synthesized in a flow system
Dede, Özlem; Kalıpçılar, Halil; Department of Chemical Engineering (2007)
Zeolite membrane synthesis is conventionally carried out in batch systems. Recently, several attempts have been performed to synthesize zeolite membranes in flow systems which can allow preparation of membranes with large specific surface areas. Membranes synthesized in the recirculating flow system had comparable N2/SF6 and n- C4H10/i-C4H10 ideal selectivities with the membranes prepared in the batch system, indicating that good quality membranes can be produced by this method. The objective of this study ...
Thermal characterization of homopolymers, copolymers and metal functional copolymers of vinylpyridines
Elmacı, Ayşegül; Hacaloğlu, Jale; Department of Polymer Science and Technology (2008)
Although, the use of vinyl pyridine polymers, especially as matrices for nanoparticle synthesis, is growing considerably, the knowledge of thermal degradation behavior is still missing in the literature. In this study, thermal degradation characteristics of the homopolymers; poly(4-vinylpyridine), P4VP, and poly(2-vinylpyridine), P2VP, the diblock copolymers; polystyrene-blockpoly( 2-vinylpyridine), (PS-b-P2VP) and polystyrene-block-poly(4-vinylpyridine), (PS-b-P4VP), and the metal functional vinyl polymers...
Dynamic analysis of changes in diffusion and sorption parameters in the reaction of SO2with activated soda ash
Doǧu, Gülsen; Keskin, Alne; Doǧu, Timur (Wiley, 1988-8)
Variations in pore structure cause significant changes in diffusion resistance and adsorption characteristics during the reaction of SO2 with activated soda. Breakthrough and moment analysis of the SO2‐activated soda ash reaction showed that the effective diffusion coefficient of SO2 in the solid product (mostly Na2SO3) was about three times smaller than its value in the original activated soda. About 30% of the diffusion flux of SO2 in the solid product was found to be due to surface diffusion. The adsorpt...
Application of semi conductor films over glass/ceramic surfaces and their low temperature photocatalytic activity
Ersöz, Tuğçe İrfan; Karakaş, Gürkan; Department of Chemical Engineering (2009)
Semiconductor metal oxides can be induced by light with proper wavelength resulting in oxidation and reduction reactions for the transformation of water and oxygen molecules into active radicals. With this method, it is possible to obtain self-cleaning surfaces and products having antimicrobial properties. The aim of this study is to develop semiconductor metal oxide thin films for multifunctional glass products and the characterization of photocatalytic self cleaning and antimicrobial properties. As semico...
Synthesis of low silica/alumina zeolite membranes in a flow system
Akbay, Sezin; Kalıpçılar, Halil; Department of Chemical Engineering (2007)
Zeolite A-type membranes are usually synthesized from hydrogels and rarely synthesized from clear solutions mostly in batch systems. Few studies were carried out using semi-continuous systems for zeolite A membrane synthesis. Zeolite A membranes are mainly used in pervaporation processes for separation of water from water/organic mixtures because of their hydrophilic property. In this study, zeolite A membranes were synthesized on -alumina supports from a clear solution with a molar composition of 49Na2O: ...
Citation Formats
B. Arıcan Yüksel, “Pervaporation of ethanol/water mixtures by zeolite A membranes synthesized in batch and flow systems,” M.S. - Master of Science, Middle East Technical University, 2011.