Show/Hide Menu
Hide/Show Apps
Logout
Türkçe
Türkçe
Search
Search
Login
Login
OpenMETU
OpenMETU
About
About
Open Science Policy
Open Science Policy
Open Access Guideline
Open Access Guideline
Postgraduate Thesis Guideline
Postgraduate Thesis Guideline
Communities & Collections
Communities & Collections
Help
Help
Frequently Asked Questions
Frequently Asked Questions
Guides
Guides
Thesis submission
Thesis submission
MS without thesis term project submission
MS without thesis term project submission
Publication submission with DOI
Publication submission with DOI
Publication submission
Publication submission
Supporting Information
Supporting Information
General Information
General Information
Copyright, Embargo and License
Copyright, Embargo and License
Contact us
Contact us
Polycarbonate based zeolite 4a filled mixed matrix membranes: preparation, characterization and gas separation performances
Download
index.pdf
Date
2008
Author
Şen, Değer
Metadata
Show full item record
Item Usage Stats
320
views
142
downloads
Cite This
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 altered by incorporating p-nitroaniline (pNA) as a LMWA and the PC membrane morphology was modified by introducing zeolite 4A particles as fillers. For this purpose, pure PC and PC/pNA dense homogenous membranes, and PC/zeolite 4A and PC/pNA/zeolite 4A mixed matrix membranes (MMM) were prepared by solvent-evaporation method using dichloromethane as the solvent. The pNA and zeolite 4A concentrations in the casting solutions were changed between 1-5% (w/w) and 5-30% (w/w), respectively. Membranes were characterized by SEM, DSC, and single gas permeability measurements of N2, H2, O2, CH4 and CO2. They were also tested for their binary gas separation performances with CO2/CH4, CO2/N2 and H2/CH4 mixtures at different feed gas compositions. DSC analysis of the membranes showed that, incorporation of zeolite 4A particles into PC/pNA increased the glass transition temperatures, Tg, but incorporation of them to pure PC had no effect on the Tg, suggesting that pNA was a necessary agent for interaction between zeolite 4A and PC matrix. The ideal selectivities increased in the order of pure PC, PC/zeolite 4A MMMs and PC/pNA/zeolite 4A MMMs despite a loss in the permeabilities with respect to pure PC. A significant improvement was achieved in selectivities when the PC/pNA/zeolite 4A MMMs were prepared with pNA concentrations of 1 % and 2 % (w/w) and with a zeolite loading of 20 % (w/w). The H2/CH4 and CO2/CH4 selectivities of PC/pNA (1%)/zeolite 4A (20%) membrane were 121.3 and 51.8, respectively, which were three times higher than those of pure PC membrane. Binary gas separation performance of the membranes showed that separation selectivities of pure PC and PC/pNA homogenous membranes were nearly the same as the ideal selectivities regardless of the feed gas composition. On the other hand, for PC/zeolite 4A and PC/pNA/zeolite 4A MMMs, the separation selectivities were always lower than the respective ideal selectivities for all binary gas mixtures, and demonstrated a strong feed composition dependency indicating the importance of gas-membrane matrix interactions in MMMs. For CO2/CH4 binary gas mixture, when the CO2 concentration in the feed increased to 50 %, the selectivities decreased from 31.9 to 23.2 and 48.5 to 22.2 for PC/zeolite 4A (20%) and PC/pNA (2%)/zeolite 4A (20%) MMMs, respectively. In conclusion, high performance PC based MMMs were prepared by blending PC with small amounts of pNA and introducing zeolite 4A particles. The prepared membranes showed promising results to separate industrially important gas mixtures depending on the feed gas compositions.
Subject Keywords
Membranes (Technology)
,
Gas separation.
URI
http://etd.lib.metu.edu.tr/upload/12609348/index.pdf
https://hdl.handle.net/11511/17593
Collections
Graduate School of Natural and Applied Sciences, Thesis
Suggestions
OpenMETU
Core
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 ...
Fabrication of polyethersulfone hollow fibers for ultrafiltration
Kaltalı, Gülçin; Çulfaz Emecen, Pınar Zeynep; Kalıpçılar, Halil; Department of Chemical Engineering (2014)
Hollow fiber membranes take an important part in membrane separation processes. They are used in many areas like gas separation, pervaporation, ultrafiltration and microfiltration processes due to their advantages like high membrane area per volume and easy backwashability. Poly(ethersulfone) (PES) is one of the most commonly used polymers in preparing hollow fiber ultrafiltration membranes. Due to its hydrophobic character, use of hydrophilic additives is usually necessary to make membranes resistant to fo...
Polyimide and PEBAX flat and hollow fiber membranes for gas separation
Özdemir, Nur Konçüy; Kalıpçılar, Halil; Department of Chemical Engineering (2017)
This thesis analyzes the effect of polyimide (PI) hollow fiber membrane spinning conditions including dope solution flow rate, bore liquid flow rate, addition of more volatile solvent to dope solution, air gap height and heating zone temperature on the ideal gas separation performance and membrane morphology. The effect of PEBAX1657 coating of PI hollow fiber membrane was also investigated. The effect of incorporation of ZIF-8 crystals to PEBAX1657 flat sheet membrane, the effect of coagulant type for the p...
Fabrication of helical polymeric hollow fiber membranes and characterization of their fouling behaviours
Yücel, Hazal; Çulfaz Emecen, Pınar Zeynep; Department of Chemical Engineering (2018)
Membranes are used in many separation processes such as gas separation, microfiltration, ultrafiltration and hemodialysis. Hollow fiber membranes are advantageous since they have a high surface area per volume and are easily backwashed which is an advantage for fouling removal. The most important factors that affect the performance of filtration membranes are concentration polarization and fouling. They increase operational cost and reduce membrane lifetime and permeate flux. One approach that can reduce co...
Electro-chemo-mechanical induced fracture modeling in proton exchange membrane water electrolysis for sustainable hydrogen production
Aldakheel, Fadi; Kandekar, Chaitanya; Bensmann, Boris; Dal, Hüsnü; Hanke-Rauschenbach, Richard (2022-10-01)
This work provides a framework for predicting fracture of catalyst coated membrane (CCM) due to coupled electro-chemo-mechanical degradation processes in proton exchange membrane water electrolysis (PEMWE) cells. Electrolysis in the catalyst layer (CL) bulk, diffusion of Hydrogen proton through the membrane (MEM), and mechanical compression at the interface with the porous transport layer (PTL) generate micro-cracks that influence the catalyst degradation. Based on our experimental observations, we propose ...
Citation Formats
IEEE
ACM
APA
CHICAGO
MLA
BibTeX
D. Şen, “Polycarbonate based zeolite 4a filled mixed matrix membranes: preparation, characterization and gas separation performances,” Ph.D. - Doctoral Program, Middle East Technical University, 2008.
