Effect of Midsynthesis Addition of Silica to the Synthesis Medium on the Properties of MFI-Type Zeolite Membranes

Soydas, Belma
Kalıpçılar, Halil
Culfaz, Ali
Thin zeolite membranes of MFI type were prepared on alpha-Al2O3 supports by midsynthesis addition of silica in a recirculating flow system at 95 degrees C The synthesis was started with the batch composition of 80SiO(2): 30TPAOH:1500H(2)O which was changed to 80SiO(2)center dot 9TPAOH:1500H(2)O by addition of silica Mkt 24, 48, or 72 h Compared to synthesis at constant composition. it is possible to affect the rates of nucleation and crystal growth to obtain membranes with better quality by changing the overall composition of the medium during the membrane synthesis The membranes produced with and without midsynthesis addition of silica have n-C4H10/i-C4H10 ideal selectivities of 47 and 8 at 100 degrees C, respectively Among these membranes, the ones formed with midsynthesis addition of silica at 24 h yielded the highest n-C4H10/CH4 separation selectivities, which were over 20 at 25 degrees C The time at which the silica is introduced to the synthesis medium is critical for the membrane quality


Effect of Alkyl Derivatization on Several Properties of N-Halamine Antimicrobial Siloxane Coatings
Kocer, Hasan B.; Akdağ, Akın; Ren, Xuehong; Broughton, R. M.; Worley, S. D.; Huang, T. S. (American Chemical Society (ACS), 2008-10-01)
Variation of alkyl substitution at position 5 on the hydantoin ring of a series of N-halamine siloxane derivatives has been employed to better understand the biocidal activities of these compounds for use in preparing antimicrobial coatings. The alkyl derivatization of the hydantoin ring at its 5 position, while an essentially constant chlorine loading is maintained at the I position, has shown that there is little dependence of the antimicrobial efficacy against Escherichia coli O157:H7 on the alkyl chain ...
Effect of Gas Diffusion Layer Characteristics and Addition of Pore-Forming Agents on the Performance of Polymer Electrolyte Membrane Fuel Cells
Senguel, Erce; Erkan, Serdar; Eroğlu, İnci; BAÇ, NURCAN (Informa UK Limited, 2009-01-01)
The performance of five layer membrane electrode assemblies having different characteristics of gas diffusion layers was determined at 70 degrees C cell temperature and ambient pressure. The maximum power density at 0.6 V was 0.36 W/cm(2) for the membrane electrode assembly prepared with the gas diffusion layer having minimum thickness (SGL BC 30 type). On the other hand, the maximum power density at 0.5 V was 0.44 W/cm(2) for the membrane electrode assembly prepared with SGL BC 34 type gas diffusion layer....
Enhancement of biodegradability by continuous ozonation in Acid Red-151 solutions and kinetic modeling
Gokcen, F; Ozbelge, TA (Elsevier BV, 2005-11-15)
In this work, continuous ozonation of aqueous Acid Red-151 was performed in a stirred tank reactor at neutral pH and 25 degrees C. The results show that ozonation is capable of a rapid conversion of the Acid Red-151 dye molecule to more biodegradable intermediates up to the ozonation time of 120 min at which the optimum BOD5/COD ratio is obtained. The peak BOD5/COD ratios were found to be in the range of 0.028-0.35 for the initial dye concentrations being in the range of 1000-100 mg/L, respectively.
Synthesis of ZSM-5 and SAPO-34 membranes in a high temperature-pressure recirculating-flow system
TOPUZ, BERNA; Onder, Aylin; Bowen, Travis C.; Kalıpçılar, Halil (Elsevier BV, 2017-01-01)
MFI and SAPO-34 type zeolite membranes were prepared on tubular alumina supports in a recirculating flow system at elevated temperatures and reported for the first time in the literature. During membrane synthesis, the synthesis mixture flowed between the reservoir and the membrane module, which includes the membrane support. The highest synthesis temperatures were 180 degrees C and 220 degrees C, and the corresponding system pressures were approximately 20 and 30 bar for MFI and SAPO-34, respectively. The ...
Effects of pH, Initiator, Scavenger, and Surfactant on the Ozonation Mechanism of an Azo Dye (Acid Red-151) in a Batch Reactor
Oezbelge, Tuelay A.; Erol, Funda (Informa UK Limited, 2009-01-01)
In this study, an initiator (Fe2+) and a scavenger (CO32(-)) were used at different concentrations in a batch reactor to investigate the reaction mechanism of ozonation of a model azo dye, namely Acid Red-151 (AR-151). Also, the effect of a nonionic surfactant known as a major pollutant in many industrial wastewaters, namely polyethylene glycol (PEG), was observed on the degradation rate of AR-151. The experimental parameters and their ranges were: pH (2.5-10), initiator (0.8-50mg/L of Fe2+), surfactant (10...
Citation Formats
B. Soydas, H. Kalıpçılar, and A. Culfaz, “Effect of Midsynthesis Addition of Silica to the Synthesis Medium on the Properties of MFI-Type Zeolite Membranes,” INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, pp. 5407–5414, 2010, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/39222.