Vapor separation by mixed matrix polymeric membranes

Şahin, Fatma
ZIF-8, ZIF-L, ZIF-7 and ZIF-67 were synthesized from fresh and recycled synthesis solutions. The crystal morphology, N2 adsorption capacity and thermal behavior of ZIFs from recycled solutions were similar to those obtained from the fresh solution. The recycling procedures improved the efficiency of crystallization such that 0.36 g ZIF-7/g organic linker was obtained after two recycling steps, although only 0.16 g ZIF-7/ g organic linker can be obtained after single step synthesis using fresh solution. From an environmental perspective, the developed procedures allowed to consume a great extent of organic linker used for synthesis, therefore the amount of waste organic linker was reduced. A PDMS-based membrane is potentially appropriate for separation of organic solvents from N2. Six different membrane - pure PDMS membrane, ZIF-8/PDMS MMMs, ZIF-L/PDMS MMMs, ZIF-67/PDMS MMMs, ZIF-7/PDMS MMMs and ZIF-71/PDMS MMMs were prepared. Incorporation of ZIF-L enhanced the VOCs permeability and VOC/N2 selectivity by 60 % and 33 % with respect to pure PDMS membrane. Single VOCs/N2 mixtures and multicomponent VOCs/N2 mixtures were tested at different temperatures. It was found that VOCs and N2 showed inverse response with temperature change. Effect of VOCs concentration in the feed stream was determined via decreasing VOCs concentration by 1 % in the feed stream. It was observed that VOCs permeability and α VOCs/N2 decreased % 27 and 40 %, respectively.


Synthesis of ZIF-7, ZIF-8, ZIF-67, and ZIF-L from recycled mother liquors
Sahin, Fatma; Topuz, Benia; Kalıpçılar, Halil (2018-05-01)
ZIF-8, ZIF-L, ZIF-7 and ZIF-67 were synthesized from fresh and recycled synthesis solutions. ZIF-8, ZIF-L and ZIF-67 includes Zn2+, while ZIF-67 includes Co2+. ZIF-67 was synthesized in dimethyl formamide, while the others in water. The organic linker was 2-methyl imidazole for ZIF-8, ZIF-L and ZIF-67, and benzimidazole for ZIF-67. The recycling was proceeded two steps for each type of ZIF. For the synthesis in the recycled solutions, the pH and the metal ion content of the mother liquor should be adjusted ...
Development and characterization of composite proton exchange membranes for fuel cell applications
Akay, Ramiz Gültekin; Baç, Nurcan; Department of Chemical Engineering (2008)
Intensive research on development of alternative low cost, high temperature membranes for proton exchange membrane (PEM) fuel cells is going on because of the well-known limitations of industry standard perfluoro-sulfonic acid (PFSA) membranes. To overcome these limitations such as the decrease in performance at high temperatures (>80 0C) and high cost, non-fluorinated aromatic hydrocarbon based polymers are attractive. The objective of this study is to develop alternative membranes that possess comparable ...
Polymer-immobilized palladium supported on TiO2 (Pd-PVB-TiO2) as highly active and reusable catalyst for hydrogen generation from the hydrolysis of unstirred ammonia-borane solution
Rakap, Murat; Kalu, Egwu Eric; Özkar, Saim (Elsevier BV, 2011-01-01)
Herein we report the preparation, characterization and the catalytic use of the polymer-immobilized palladium catalyst supported on TiO2 (Pd-PVB-TiO2) in the hydrolysis of unstirred ammonia-borane solution. The polymer-immobilized palladium catalyst is stable enough to be isolated as solid materials and characterized by XRD, SM, and EDX. The immobilized palladium catalyst supported on TiO2 is found highly active, isolable, and reusable in the hydrolysis of unstirred ammonia-borane even at low concentrations...
Adsorption of volatile organic compounds on soil and prediction of desorption breakthroughs
Yeo, SD; Tuncer, E; Akgerman, A (Informa UK Limited, 1997-01-01)
Vapor extraction of volatile organic compounds from soil was investigated by performing adsorption and desorption experiments of trichloroethylene, trichloroethane, and chlorobenzene on soil particles. The adsorption breakthrough curves were obtained using a dynamic response technique based on frontal analysis chromatography. The shape of the breakthrough curves indicated that the adsorption process was close to an ideal adsorption system of no mass transfer resistance, no axial dispersion, and infinitesima...
Polycarbonate based zeolite 4a filled mixed matrix membranes: preparation, characterization and gas separation performances
Şen, Değer; Yılmaz, Levent; Department of Chemical Engineering (2008)
Developing new membrane morphologies and modifying the existing membrane materials are required to obtain membranes with improved gas separation performances. The incorporation of zeolites and low molecular-weight additives (LMWA) into polymers are investigated as alternatives to modify the permselective properties of polymer membranes. In this study, these two alternatives were applied together to improve the separation performance of a polymeric membrane. The polycarbonate (PC) chain characteristics was a...
Citation Formats
F. Şahin, “Vapor separation by mixed matrix polymeric membranes,” Ph.D. - Doctoral Program, Middle East Technical University, 2018.