{"id":{"repo_id":"aachen","oai_identifier":"oai:publications.rwth-aachen.de:52093"},"canonical_url":"https://search.dev.ndltd.org/etd/aachen/oai:publications.rwth-aachen.de:52093","repository":{"repo_id":"aachen","name":"RWTH Aachen University","base_url":"https://publications.rwth-aachen.de/oai2d"},"display":{"title":"Novel methods and materials in development of liquid carrier membranes : from the molecule to the process","abstract":"This thesis attempts a complete coverage of theoretical and experimental approaches necessary for the development of the separation process of gases or vapours by the means of supported liquid carrier membranes based on ionic liquids (ILs). Firstly, state-of-the-art simulation software Femlab has been used for the mass transport modelling, where a simple mass transport model for facilitated transport through a liquid carrier membrane has been set up and implemented. For maximum separation performance of the membrane separtion unit it was found that the Gibbs free enthalpy for an exemplary carrier-permeant should be in the range from -12 kJ/mol to -18 kJ/mol. Secondly, quantum mechanical methods have been used and evaluated with the respect to the applicability for solving practical problems. It was found that quantum mechanical methods, which are computationally cheap enough in order not to be prohibitive for the treatment of realistic problems, can currently not accurately predict the exact thermodynamical behavior of carrier-permeant reactions. In spite of the limited applicability and deficiencies these methods, a few criteria could have been stated, by which a potential carrier among proposed chemical structures may be identified. The reaction typically should not show distinctive transition state barriers: 1. activation energy should preferably be less than 5 kJ/mol. 2. DFT methods propose favourable values of the reaction enthalpies for the potential carrier between -100 kJ/mol and -200 kJ/mol. It is in this range, where potential carriers should be searched for. In the last part membrane experiments have been focused. Surface tension and wetting influence the transmembrane pressures that can be applied to supported liquid membrane (maximum 12 bar). The pressures that can be applied to ceramic support that potentially enable scale-up of the membrane separation unit are, however in the range of 3 to 4 bar. The solubility of different gases (oxygen and nitrogen) and vapours (propylene and propane) has been investigated. It has been found that the solubility ratio of these vapours and gases behave no different than in other, more commonly used solvents. The solubility of propylene and oxygen is twice as high as that of propane and nitrogen, independent of the ionic liquid used. The solubility of gases and vapours in the membrane phase has shown a higher impact on the performance of the solution-diffusion liquid membranes than their diffusivity. Since the diffusion coefficients for propane and propylene as well as for oxygen and nitrogen are very similar, it was not surprising to find the experimental perm-selectivities and selectivities for these two separation problems around value of 2, which approximately correspond to the the ratio of the respective Henry’s coefficients. The selectivity in membrane permeation experiments decreases with temperature, because the gas/vapour solubility decreases with increasing temperature. The absolute fluxes are with maximum values of about 40 dm3/m2 h bar rather small. This is due to the considerable membrane thickness, which could not be reduced. All attempts following the carrier approach in this thesis failed to give any satisfying results. The main reason is that classical carriers for propylene/propane separation (silver and cooper salts) have extremely low solubility in ionic liquids. A carrier for oxygen could be well dissolved in ionic liquid, however, it deactivated in the liquids phase, probably due to the carrier dimerisation or to strong coordination of the carrier’s active site.","abstract_html":"This thesis attempts a complete coverage of theoretical and experimental approaches necessary for the development of the separation process of gases or vapours by the means of supported liquid carrier membranes based on ionic liquids (ILs). Firstly, state-of-the-art simulation software Femlab has been used for the mass transport modelling, where a simple mass transport model for facilitated transport through a liquid carrier membrane has been set up and implemented. For maximum separation performance of the membrane separtion unit it was found that the Gibbs free enthalpy for an exemplary carrier-permeant should be in the range from -12 kJ/mol to -18 kJ/mol. Secondly, quantum mechanical methods have been used and evaluated with the respect to the applicability for solving practical problems. It was found that quantum mechanical methods, which are computationally cheap enough in order not to be prohibitive for the treatment of realistic problems, can currently not accurately predict the exact thermodynamical behavior of carrier-permeant reactions. In spite of the limited applicability and deficiencies these methods, a few criteria could have been stated, by which a potential carrier among proposed chemical structures may be identified. The reaction typically should not show distinctive transition state barriers: 1. activation energy should preferably be less than 5 kJ/mol. 2. DFT methods propose favourable values of the reaction enthalpies for the potential carrier between -100 kJ/mol and -200 kJ/mol. It is in this range, where potential carriers should be searched for. In the last part membrane experiments have been focused. Surface tension and wetting influence the transmembrane pressures that can be applied to supported liquid membrane (maximum 12 bar). The pressures that can be applied to ceramic support that potentially enable scale-up of the membrane separation unit are, however in the range of 3 to 4 bar. The solubility of different gases (oxygen and nitrogen) and vapours (propylene and propane) has been investigated. It has been found that the solubility ratio of these vapours and gases behave no different than in other, more commonly used solvents. The solubility of propylene and oxygen is twice as high as that of propane and nitrogen, independent of the ionic liquid used. The solubility of gases and vapours in the membrane phase has shown a higher impact on the performance of the solution-diffusion liquid membranes than their diffusivity. Since the diffusion coefficients for propane and propylene as well as for oxygen and nitrogen are very similar, it was not surprising to find the experimental perm-selectivities and selectivities for these two separation problems around value of 2, which approximately correspond to the the ratio of the respective Henry’s coefficients. The selectivity in membrane permeation experiments decreases with temperature, because the gas/vapour solubility decreases with increasing temperature. The absolute fluxes are with maximum values of about 40 dm3/m2 h bar rather small. This is due to the considerable membrane thickness, which could not be reduced. All attempts following the carrier approach in this thesis failed to give any satisfying results. The main reason is that classical carriers for propylene/propane separation (silver and cooper salts) have extremely low solubility in ionic liquids. A carrier for oxygen could be well dissolved in ionic liquid, however, it deactivated in the liquids phase, probably due to the carrier dimerisation or to strong coordination of the carrier’s active site.","abstract_has_math":false,"creators":["Medved, Mitja"],"institution":"Publikationsserver der RWTH Aachen University","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Melin, Thomas"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2006,"date_issued":"2006","date_published":"2006","updated_at":"2026-07-30T19:40:50Z","subjects":["info:eu-repo/classification/ddc/660","Technische Chemie","Membran","Mathematisches Modell","Stoffübertragung","Quantenmechanik","Thermochemie","Stofftransportmodellierung","Finite-Elemente-Methode","Membranexperimente"],"languages":["eng"],"rights":["info:eu-repo/semantics/openAccess"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-114335%22"],"render_values":[{"text":"https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-114335%22","href":"https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-114335%22","code":true}]}]},"links":{"outbound_url":"https://publications.rwth-aachen.de/record/52093","outbound_label":"Repository record","outbound_source":"dc:identifier"},"source_record":{"url":"https://publications.rwth-aachen.de/oai2d?verb=GetRecord&metadataPrefix=oai_dc&identifier=oai%3Apublications.rwth-aachen.de%3A52093","prefix":"oai_dc"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Melin, Thomas"]},{"key":"dc:creator","label":"Author","values":["Medved, Mitja"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:coverage","label":"Dc Coverage","values":["DE"]},{"key":"dc:date","label":"Dc Date","values":["2006"]},{"key":"dc:publisher","label":"Institution","values":["Publikationsserver der RWTH Aachen University"]},{"key":"dc:relation","label":"Dc Relation","values":["info:eu-repo/semantics/altIdentifier/urn/urn:nbn:de:hbz:82-opus-16165"]},{"key":"dc:type","label":"Dc Type","values":["info:eu-repo/semantics/doctoralThesis","info:eu-repo/semantics/publishedVersion"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["info:eu-repo/classification/ddc/660","Technische Chemie","Membran","Mathematisches Modell","Stoffübertragung","Quantenmechanik","Thermochemie","Stofftransportmodellierung","Finite-Elemente-Methode","Membranexperimente"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["info:eu-repo/semantics/openAccess"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://publications.rwth-aachen.de/record/52093","https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-114335%22"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["This thesis attempts a complete coverage of theoretical and experimental approaches necessary for the development of the separation process of gases or vapours by the means of supported liquid carrier membranes based on ionic liquids (ILs). Firstly, state-of-the-art simulation software Femlab has been used for the mass transport modelling, where a simple mass transport model for facilitated transport through a liquid carrier membrane has been set up and implemented. For maximum separation performance of the membrane separtion unit it was found that the Gibbs free enthalpy for an exemplary carrier-permeant should be in the range from -12 kJ/mol to -18 kJ/mol. Secondly, quantum mechanical methods have been used and evaluated with the respect to the applicability for solving practical problems. It was found that quantum mechanical methods, which are computationally cheap enough in order not to be prohibitive for the treatment of realistic problems, can currently not accurately predict the exact thermodynamical behavior of carrier-permeant reactions. In spite of the limited applicability and deficiencies these methods, a few criteria could have been stated, by which a potential carrier among proposed chemical structures may be identified. The reaction typically should not show distinctive transition state barriers: 1. activation energy should preferably be less than 5 kJ/mol. 2. DFT methods propose favourable values of the reaction enthalpies for the potential carrier between -100 kJ/mol and -200 kJ/mol. It is in this range, where potential carriers should be searched for. In the last part membrane experiments have been focused. Surface tension and wetting influence the transmembrane pressures that can be applied to supported liquid membrane (maximum 12 bar). The pressures that can be applied to ceramic support that potentially enable scale-up of the membrane separation unit are, however in the range of 3 to 4 bar. The solubility of different gases (oxygen and nitrogen) and vapours (propylene and propane) has been investigated. It has been found that the solubility ratio of these vapours and gases behave no different than in other, more commonly used solvents. The solubility of propylene and oxygen is twice as high as that of propane and nitrogen, independent of the ionic liquid used. The solubility of gases and vapours in the membrane phase has shown a higher impact on the performance of the solution-diffusion liquid membranes than their diffusivity. Since the diffusion coefficients for propane and propylene as well as for oxygen and nitrogen are very similar, it was not surprising to find the experimental perm-selectivities and selectivities for these two separation problems around value of 2, which approximately correspond to the the ratio of the respective Henry’s coefficients. The selectivity in membrane permeation experiments decreases with temperature, because the gas/vapour solubility decreases with increasing temperature. The absolute fluxes are with maximum values of about 40 dm3/m2 h bar rather small. This is due to the considerable membrane thickness, which could not be reduced. All attempts following the carrier approach in this thesis failed to give any satisfying results. The main reason is that classical carriers for propylene/propane separation (silver and cooper salts) have extremely low solubility in ionic liquids. A carrier for oxygen could be well dissolved in ionic liquid, however, it deactivated in the liquids phase, probably due to the carrier dimerisation or to strong coordination of the carrier’s active site."]},{"key":"dc:source","label":"Dc Source","values":["Aachen : Publikationsserver der RWTH Aachen University XV, 241 S. : Ill., graph. Darst. (2006). = Aachen, Techn. Hochsch., Diss., 2006"]},{"key":"dc:title","label":"Title","values":["Novel methods and materials in development of liquid carrier membranes : from the molecule to the process"]}]}],"canonical_facts":{"dc:contributor":["Melin, Thomas"],"dc:coverage":["DE"],"dc:creator":["Medved, Mitja"],"dc:date":["2006"],"dc:description":["This thesis attempts a complete coverage of theoretical and experimental approaches necessary for the development of the separation process of gases or vapours by the means of supported liquid carrier membranes based on ionic liquids (ILs). Firstly, state-of-the-art simulation software Femlab has been used for the mass transport modelling, where a simple mass transport model for facilitated transport through a liquid carrier membrane has been set up and implemented. For maximum separation performance of the membrane separtion unit it was found that the Gibbs free enthalpy for an exemplary carrier-permeant should be in the range from -12 kJ/mol to -18 kJ/mol. Secondly, quantum mechanical methods have been used and evaluated with the respect to the applicability for solving practical problems. It was found that quantum mechanical methods, which are computationally cheap enough in order not to be prohibitive for the treatment of realistic problems, can currently not accurately predict the exact thermodynamical behavior of carrier-permeant reactions. In spite of the limited applicability and deficiencies these methods, a few criteria could have been stated, by which a potential carrier among proposed chemical structures may be identified. The reaction typically should not show distinctive transition state barriers: 1. activation energy should preferably be less than 5 kJ/mol. 2. DFT methods propose favourable values of the reaction enthalpies for the potential carrier between -100 kJ/mol and -200 kJ/mol. It is in this range, where potential carriers should be searched for. In the last part membrane experiments have been focused. Surface tension and wetting influence the transmembrane pressures that can be applied to supported liquid membrane (maximum 12 bar). The pressures that can be applied to ceramic support that potentially enable scale-up of the membrane separation unit are, however in the range of 3 to 4 bar. The solubility of different gases (oxygen and nitrogen) and vapours (propylene and propane) has been investigated. It has been found that the solubility ratio of these vapours and gases behave no different than in other, more commonly used solvents. The solubility of propylene and oxygen is twice as high as that of propane and nitrogen, independent of the ionic liquid used. The solubility of gases and vapours in the membrane phase has shown a higher impact on the performance of the solution-diffusion liquid membranes than their diffusivity. Since the diffusion coefficients for propane and propylene as well as for oxygen and nitrogen are very similar, it was not surprising to find the experimental perm-selectivities and selectivities for these two separation problems around value of 2, which approximately correspond to the the ratio of the respective Henry’s coefficients. The selectivity in membrane permeation experiments decreases with temperature, because the gas/vapour solubility decreases with increasing temperature. The absolute fluxes are with maximum values of about 40 dm3/m2 h bar rather small. This is due to the considerable membrane thickness, which could not be reduced. All attempts following the carrier approach in this thesis failed to give any satisfying results. The main reason is that classical carriers for propylene/propane separation (silver and cooper salts) have extremely low solubility in ionic liquids. A carrier for oxygen could be well dissolved in ionic liquid, however, it deactivated in the liquids phase, probably due to the carrier dimerisation or to strong coordination of the carrier’s active site."],"dc:identifier":["https://publications.rwth-aachen.de/record/52093","https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-114335%22"],"dc:language":["eng"],"dc:publisher":["Publikationsserver der RWTH Aachen University"],"dc:relation":["info:eu-repo/semantics/altIdentifier/urn/urn:nbn:de:hbz:82-opus-16165"],"dc:rights":["info:eu-repo/semantics/openAccess"],"dc:source":["Aachen : Publikationsserver der RWTH Aachen University XV, 241 S. : Ill., graph. Darst. (2006). = Aachen, Techn. Hochsch., Diss., 2006"],"dc:subject":["info:eu-repo/classification/ddc/660","Technische Chemie","Membran","Mathematisches Modell","Stoffübertragung","Quantenmechanik","Thermochemie","Stofftransportmodellierung","Finite-Elemente-Methode","Membranexperimente"],"dc:title":["Novel methods and materials in development of liquid carrier membranes : from the molecule to the process"],"dc:type":["info:eu-repo/semantics/doctoralThesis","info:eu-repo/semantics/publishedVersion"]},"updated_at":"2026-07-30T19:40:50Z"}