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
Investigation of phase inversion behavior of cellulose- ionic liquid solutions in relationship with membrane formation
Download
index.pdf
Date
2017
Author
Durmaz, Elif Nur
Metadata
Show full item record
Item Usage Stats
336
views
171
downloads
Cite This
Cellulose membranes were produced from ionic liquid solutions by phase inversion technique and thermodynamic and kinetic aspects of the process were investigated to relate these to membrane morphology and performance. In thermodynamics part, polymer-solvent, polymer-nonsolvent and polymer-solvent-nonsolvent interactions were examined experimentally, together with Hansen solubility parameter estimations. Kinetics part consisted of measuring phase inversion rate. Obtained membranes were characterized by their morphology, crystallinity and separation performances. Performances and SEM images of cellulose, cellulose acetate and poly(ether sulfone), PES, membranes show that when amount of ionic liquid (1-ethyl-3- methylimidazolium acetate, EMIMAc) increased in the polymer solution and when the coagulation media is water rather than ethanol, membranes have denser selective layer. Bromothymol Blue retentions of non-dried cellulose membranes drop from 40% to 20% as dimethyl sulfoxide (DMSO) is added to the polymer solution in 1:1 ratio with ionic liquid and when it is added in 1:2 ratio retention reduced to approximately 10%. Rejections are not more than 7% for membranes obtained from coagulation in ethanol. Additionally when membranes were dried, Bromothymol Blue retentions increased to ca. 80% for all cellulose membranes while pure ethanol permeance drops to approximately 1 L/m2.h.bar from around 70 L/m2.h.bar. XRD measurements of cellulose membranes indicate the highest crystallinity in membranes prepared from EMIMAc only and coagulated in water. Solubility parameters estimate that solvent quality of EMIMAc is higher for cellulose than EMIMAc-DMSO mixtures, while it is opposite for cellulose acetate and PES. The nonsolvent quality of water is found to be lower for cellulose solutions indicated by cloud point measurements and swelling tests. Cloud point and swelling test measurements and solubility parameter estimations agree that water is a stronger nonsolvent for cellulose acetate and PES. Phase inversion rates from microscope observations are always lower when the nonsolvent is ethanol. However not seeing higher front rates in lower viscosity DMSO containing solutions, imply that phase inversion front rates do not only depend on viscosities for these solutions. Light transmission measurements, on the other hand, show more reliable results on membrane porosity rather than precipitation rate of polymer solution.
Subject Keywords
Cellulose.
,
Ionic solutions.
,
Membranes (Technology).
,
Phase rule and equilibrium.
URI
http://etd.lib.metu.edu.tr/upload/12620879/index.pdf
https://hdl.handle.net/11511/26359
Collections
Graduate School of Natural and Applied Sciences, Thesis
Suggestions
OpenMETU
Core
Investigation of sludge viscosity and its effects on the performance of a vacuum rotation membrane bioreactor
KOMESLİ, Okan Tarık; Gökçay, Celal Ferdi (Informa UK Limited, 2014-03-04)
Sludge characteristics of a full-scale vacuum rotation membrane (VRM) bioreactor having plate-type membranes with 0.038 m nominal pore size and 540 m(2) surface area were investigated. The VRM plant is composed of an aeration tank and a filtration chamber. The sludge floc size distribution, as determined microscopically, was mainly between 0 and 100 m in the filter chamber with very little difference in size distribution between summer (20-25 degrees C) and winter (10-15 degrees C) seasons. Small floc size ...
Development of alumina supported ternary mixed matrix membranes for separation of H-2/light-alkane mixtures
Topuz, Berna; Yılmaz, Levent; Kalıpçılar, Halil (2012-10-01)
Ternary component mixed matrix membrane was prepared from PES, SAPO-34 and 2-hydroxy 5-methyl aniline on a macroporous alumina disk by the solvent evaporation method in order to investigate the effect of existence of an inorganic support. The membrane and its pure PES/Alumina counterpart were characterized by single gas permeability measurements of H-2, CH4, C2H6 and C3H8. The corresponding H-2/CH4 selectivities of membranes were 71.3 and 41. The membranes were also used to separate equimolar mixtures of H-...
Effect of crosslinking on organic solvent nanofiltration performance of cellulose membranes
Konca, Kübra; Çulfaz Emecen, Pınar Zeynep; Department of Chemical Engineering (2018)
Nanofiltration is a membrane process capable of separation of small molecules and multivalent ions due to their size and/or charge. NF is mainly used in aqueous applications. However, there are many processes that can take advantages of NF in molecules separation dissolved in organic solvents. Main challenge in Organic Solvent Nanofiltration is the limited number of membranes which can withstand a wide range solvents and have stable, predictable separation performance. Cellulose is an alternative polymer th...
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 ...
Development of polybenzimidazole/graphene oxide composite membranes for high temperature PEM fuel cells
Uregen, Nurhan; Pehlivanoglu, Kubra; Ozdemir, Yagmur; DEVRİM, YILSER (2017-01-26)
In this study, phosphoric acid doped Polybenzimidazole/Graphene Oxide (PBI/GO) nano composite membranes were prepared by dispersion of various amounts of GO in PBI polymer matrix followed by phosphoric acid doping for high temperature proton exchange membrane fuel cell (HT-PEMFC) application. The structure of the PBI/GO composite membranes was investigated by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and by thermogravimetric analysis (TGA). The introduction of GO into the FBI polymer matri...
Citation Formats
IEEE
ACM
APA
CHICAGO
MLA
BibTeX
E. N. Durmaz, “Investigation of phase inversion behavior of cellulose- ionic liquid solutions in relationship with membrane formation,” M.S. - Master of Science, Middle East Technical University, 2017.
