Chemical Crosslinking of 6FDA-ODA and 6FDA-ODA:DABA for Improved CO2/CH4 Separation
Chemical grafting or crosslinking of polyimide chains are known to be feasible approaches to increase polymer gas-pair selectivity and specific gas permeance. Different co-polyimides; 6FDA-ODA and 6FDA-ODA:DABA were synthesized using a two-step condensation method. Six different cross-linkers were u...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2018-08-01
|
| Series: | Membranes |
| Subjects: | |
| Online Access: | http://www.mdpi.com/2077-0375/8/3/67 |
| _version_ | 1827848186136363008 |
|---|---|
| author | Mohd Zamidi Ahmad Henri Pelletier Violeta Martin-Gil Roberto Castro-Muñoz Vlastimil Fila |
| author_facet | Mohd Zamidi Ahmad Henri Pelletier Violeta Martin-Gil Roberto Castro-Muñoz Vlastimil Fila |
| author_sort | Mohd Zamidi Ahmad |
| collection | DOAJ |
| description | Chemical grafting or crosslinking of polyimide chains are known to be feasible approaches to increase polymer gas-pair selectivity and specific gas permeance. Different co-polyimides; 6FDA-ODA and 6FDA-ODA:DABA were synthesized using a two-step condensation method. Six different cross-linkers were used: (i) m-xylylene diamine; (ii) n-ethylamine; and (iii) n-butylamine, by reacting with 6FDA-ODA’s imide groups in a solid state crosslinking; while (iv) ethylene glycol monosalicylate (EGmSal); (v) ethylene glycol anhydrous (EGAn); and (vi) thermally labile iron (III) acetylacetonate (FeAc), by reacting with DABA carboxyl groups in 6FDA-ODA:DABA. The gas separation performances were evaluated by feeding an equimolar CO2 and CH4 binary mixture, at a constant feed pressure of 5 bar, at 25 °C. Fractional free volume (FFV) was calculated using Bondi’s contribution method by considering the membrane solid density property, measured by pycnometer. Other characterization techniques: thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) were performed accordingly. Depending on the type of amine, the CO2/CH4 selectivity of 6FDA-ODA increased between 25 to 100% at the expense of CO2 permeance. We observed the similar trend for 6FDA-ODA:DABA EGmSal-crosslinked with 143% selectivity enhancement. FeAc-crosslinked membranes showed an increment in both selectivity and CO2 permeability by 126% and 29% respectively. Interestingly, FeAc acted as both cross-linker which reduces chain mobility; consequently improving the selectivity and as micro-pore former; thus increases the gas permeability. The separation stability was further evaluated using 25–75% CO2 in the feed with CH4 as the remaining, between 2 and 8 bar at 25 °C. We also observed no CO2-induced plasticization to the measured pressure with high CO2 content (max. 75%). |
| first_indexed | 2024-03-12T09:43:22Z |
| format | Article |
| id | doaj.art-98c5bbd012604be7a50091076713a7a2 |
| institution | Directory Open Access Journal |
| issn | 2077-0375 |
| language | English |
| last_indexed | 2024-03-12T09:43:22Z |
| publishDate | 2018-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Membranes |
| spelling | doaj.art-98c5bbd012604be7a50091076713a7a22023-09-02T13:07:05ZengMDPI AGMembranes2077-03752018-08-01836710.3390/membranes8030067membranes8030067Chemical Crosslinking of 6FDA-ODA and 6FDA-ODA:DABA for Improved CO2/CH4 SeparationMohd Zamidi Ahmad0Henri Pelletier1Violeta Martin-Gil2Roberto Castro-Muñoz3Vlastimil Fila4Department of Inorganic Technology, University of Chemistry and Technology Prague, Technická 5, 166 28 Prague 6, Czech RepublicÉcole Nationale Supérieure des Industries Chimique, 1 Rue Grandville—BP 20451, 54001 Nancy, FranceDepartment of Inorganic Technology, University of Chemistry and Technology Prague, Technická 5, 166 28 Prague 6, Czech RepublicDepartment of Inorganic Technology, University of Chemistry and Technology Prague, Technická 5, 166 28 Prague 6, Czech RepublicDepartment of Inorganic Technology, University of Chemistry and Technology Prague, Technická 5, 166 28 Prague 6, Czech RepublicChemical grafting or crosslinking of polyimide chains are known to be feasible approaches to increase polymer gas-pair selectivity and specific gas permeance. Different co-polyimides; 6FDA-ODA and 6FDA-ODA:DABA were synthesized using a two-step condensation method. Six different cross-linkers were used: (i) m-xylylene diamine; (ii) n-ethylamine; and (iii) n-butylamine, by reacting with 6FDA-ODA’s imide groups in a solid state crosslinking; while (iv) ethylene glycol monosalicylate (EGmSal); (v) ethylene glycol anhydrous (EGAn); and (vi) thermally labile iron (III) acetylacetonate (FeAc), by reacting with DABA carboxyl groups in 6FDA-ODA:DABA. The gas separation performances were evaluated by feeding an equimolar CO2 and CH4 binary mixture, at a constant feed pressure of 5 bar, at 25 °C. Fractional free volume (FFV) was calculated using Bondi’s contribution method by considering the membrane solid density property, measured by pycnometer. Other characterization techniques: thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) were performed accordingly. Depending on the type of amine, the CO2/CH4 selectivity of 6FDA-ODA increased between 25 to 100% at the expense of CO2 permeance. We observed the similar trend for 6FDA-ODA:DABA EGmSal-crosslinked with 143% selectivity enhancement. FeAc-crosslinked membranes showed an increment in both selectivity and CO2 permeability by 126% and 29% respectively. Interestingly, FeAc acted as both cross-linker which reduces chain mobility; consequently improving the selectivity and as micro-pore former; thus increases the gas permeability. The separation stability was further evaluated using 25–75% CO2 in the feed with CH4 as the remaining, between 2 and 8 bar at 25 °C. We also observed no CO2-induced plasticization to the measured pressure with high CO2 content (max. 75%).http://www.mdpi.com/2077-0375/8/3/67gas separationpolyimidegraftingchemical crosslinkingplasticization resistance |
| spellingShingle | Mohd Zamidi Ahmad Henri Pelletier Violeta Martin-Gil Roberto Castro-Muñoz Vlastimil Fila Chemical Crosslinking of 6FDA-ODA and 6FDA-ODA:DABA for Improved CO2/CH4 Separation Membranes gas separation polyimide grafting chemical crosslinking plasticization resistance |
| title | Chemical Crosslinking of 6FDA-ODA and 6FDA-ODA:DABA for Improved CO2/CH4 Separation |
| title_full | Chemical Crosslinking of 6FDA-ODA and 6FDA-ODA:DABA for Improved CO2/CH4 Separation |
| title_fullStr | Chemical Crosslinking of 6FDA-ODA and 6FDA-ODA:DABA for Improved CO2/CH4 Separation |
| title_full_unstemmed | Chemical Crosslinking of 6FDA-ODA and 6FDA-ODA:DABA for Improved CO2/CH4 Separation |
| title_short | Chemical Crosslinking of 6FDA-ODA and 6FDA-ODA:DABA for Improved CO2/CH4 Separation |
| title_sort | chemical crosslinking of 6fda oda and 6fda oda daba for improved co2 ch4 separation |
| topic | gas separation polyimide grafting chemical crosslinking plasticization resistance |
| url | http://www.mdpi.com/2077-0375/8/3/67 |
| work_keys_str_mv | AT mohdzamidiahmad chemicalcrosslinkingof6fdaodaand6fdaodadabaforimprovedco2ch4separation AT henripelletier chemicalcrosslinkingof6fdaodaand6fdaodadabaforimprovedco2ch4separation AT violetamartingil chemicalcrosslinkingof6fdaodaand6fdaodadabaforimprovedco2ch4separation AT robertocastromunoz chemicalcrosslinkingof6fdaodaand6fdaodadabaforimprovedco2ch4separation AT vlastimilfila chemicalcrosslinkingof6fdaodaand6fdaodadabaforimprovedco2ch4separation |