Yılmaz, Levent
An emerging membrane morphology with future potential is mixed matrix membranes composed of two interpenetrating matrices of different materials. In this study, mixed matrix membranes of an amorphous glassy polymer(polyethersulfone) and hydrophilic zeolite (4A) were prepared. An elaborate membrane preparation technique that enables incorporation of high zeolite loading into the membrane was developed. Performance of membranes was tested by using a laboratory-scale gas separation apparatus. The permeation rates of N-2, CH4, Ar, O-2, CO2, and H-2 were evaluated through a dense homogeneous PES membrane and a PES-4A mixed matrix membrane. For the mixed matrix membrane, gas permeabilities were either not changed or significantly improved. The ideal separation factors of economically important gas pairs were substantially increased due to the faster permeation of H-2 and CO2 through the mixed matrix membrane. In order to understand their interaction with each ether and with membrane matrices, permeabilities and selectivities of CO2/CH4, CO2/Ar, and H-2/CH4 binaries as a function of gas composition were measured through a dense homogeneous PES membrane and a PES-4A mixed matrix membrane. Observed selectivity independence with respect to gas composition for a dense homogeneous PES membrane indicates that ternary interactions and factors like plasticization and gas fugacity do not affect the gas permeation mechanism appreciably for this type of membrane. However, selectivities demonstrated a strong concentration dependency through a PES-4A mixed matrix membrane. For CO2/CH4 and CO2/Ar systems, when the CO2 concentration in the feed increased, selectivity decreased linearly. In the case of H-2/CH4 binaries, unlike the cases with CO2 binaries, a higher H-2 concentration in the feed caused higher selectivity values, The trend was also linear with H-2 concentration in the feed. This indicates that. for mixed matrix membranes, the existence of a third component causes the gas molecules to interact with the heterogeneous membrane matrix, affecting selectivities. Selectivity dependency indicates the importance of gas-membrane matrix and gas-gas-membrane matrix interactions.


Effect of Feed Composition on the Gas Separation Performance of Binary and Ternary Mixed Matrix Membranes
Sen, Deger; Yılmaz, Levent; Kalıpçılar, Halil (Informa UK Limited, 2013-03-01)
Binary and ternary component mixed matrix membranes comprised of zeolite 4A and p-nitroaniline (pNA) in the polycarbonate (PC) matrix were prepared and appraised in gas separation. For comparison, homogenous membranes of PC and PC/pNA membranes were also investigated. The membranes were utilized to separate binary mixtures of CO2/CH4, H2/CH4, and CO2/N2. The effect of feed composition on the separation performance of membranes was investigated. Separation factors and ideal selectivities were similar for the...
Effect of fluorine substituted benzothiadiazole on electro-optical properties of donor-acceptor-donor type monomers and their polymers
Çakal, Deniz; Önal, Ahmet Muhtar (Elsevier BV, 2020-11-01)
A series of trimeric monomers bearing thiophene donor units and fluorinated analogues of benzothiadiazole acceptor units was synthesized via donor-acceptor-donor approach and polymerized electrochemically in order to investigate the effect of fluorine atom on electro-optical properties of both monomers and their corresponding polymers. All monomers exhibited solvatochromic and fluorescent properties. The introduction of fluorine atom into the conjugated backbone increased the oxidation potentials. Upon movi...
Effect of Feed Concentration in Equilibrium Parametric Pumps
Ghasem, Nayef; Orbey, H (Informa UK Limited, 1987-12)
The effect of high initial feed concentration in batch equilibrium parametric pumping was experimentally investigated at different bed temperatures and cycle times. The system studied was benzene-n-hexane over a silica gel bed. It was observed that the initial feed concentration which leads to the best separation is dictated by the shape of the equilibrium isotherms of the system. An increase in the temperature difference between hot and cold cycles was shown to improve the separation because it led to a mo...
Effect of operating parameters on the separation of sugars by nanofiltration
Aydogan, N; Gurkan, T; Yılmaz, Levent (Informa UK Limited, 1998-01-01)
Due to the complexity of fermentation mixtures, separation of solutes and secondary substrates has a special importance. Membrane processes such as nanofiltration may offer good alternatives for the separation of fermentation products or recovery of substrates. For an efficient separation, the membrane type and operating parameters such as feed flow rate, operating pressure, and feed should be optimized. In this study the separation and recovery of sugars were targeted. It was found that with an increase of...
Use of Specifically Tailored Chelating Polymers for Boron Removal from Aqueous Solutions by Polymer Enhanced Ultrafiltration
Doganay, Ceren Oktar; Ozbelge, H. Onder; Bicak, Niyazi; AYDOĞAN, NİHAL; Yılmaz, Levent (Informa UK Limited, 2011-01-01)
Two selective functional polychelatogens, namely hydroxyethylaminoglycerol functioned poly(glycidylmethacrylate (PNS) and Poly(4-Vinyl-1,3-dioxalan-2-one-co-vinyl acetate) (COP) were synthesized and utilized in polymer-enhanced ultrafiltration (PEUF) to remove boron from the aqueous solution. The effect of operating parameters on boron retention was investigated. PNS was synthesized in three molecular weights to observe the effect of molecular weight in borate retention. Increase in pH increased boron reten...
Citation Formats
T. BATTAL, N. BAC, and L. Yılmaz, “EFFECT OF FEED COMPOSITION ON THE PERFORMANCE OF POLYMER-ZEOLITE MIXED MATRIX GAS SEPARATION MEMBRANES,” SEPARATION SCIENCE AND TECHNOLOGY, pp. 2365–2384, 1995, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/47868.