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Carbon nanotubes-cellulose acetate nanocomposites: membranes for water desalination
Cellulose acetate (CA) (Mw = 52,000 Da) membranes were prepared by phase inversion (PI) using acetone as a solvent. Investigation of different preparation conditions were carried out. The effect of membrane casting thickness, CA content, coagulation bath temperature (PI temperature), solvent evapora...
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2013
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| _version_ | 1867613416453046272 |
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| access_status_str | Open Access |
| author | El Badawi, Nouran Ashraf |
| author_browse | El Badawi, Nouran Ashraf |
| author_facet | El Badawi, Nouran Ashraf |
| author_sort | El Badawi, Nouran Ashraf |
| collection | Thesis |
| dc_rights_str_mv | The author retains all rights with regard to copyright. The author certifies that written permission from the owner(s) of third-party copyrighted matter included in the thesis, dissertation, paper, or record of study has been obtained. The author further certifies that IRB approval has been obtained for this thesis, or that IRB approval is not necessary for this thesis. Insofar as this thesis, dissertation, paper, or record of study is an educational record as defined in the Family Educational Rights and Privacy Act (FERPA) (20 USC 1232g), the author has granted consent to disclosure of it to anyone who requests a copy. |
| description | Cellulose acetate (CA) (Mw = 52,000 Da) membranes were prepared by phase inversion (PI) using acetone as a solvent. Investigation of different preparation conditions were carried out. The effect of membrane casting thickness, CA content, coagulation bath temperature (PI temperature), solvent evaporation, addition of a non-solvent (deionized water), and addition of multi-walled carbon nanotubes (MWCNTs) on membrane morphology and performance (permeation rates and salt rejection rates) were investigated. Membranes morphologies were studied using scanning electron microscopy (SEM). Membranes permeations rates and salt rejection rates were investigated using 1000 ppm NaCl solution. Optimum conditions for developing a CA based nanocomposites were attained, entailing 15 wt% CA content, 20 wt% H2O non-solvent additive, low functionalized CNTs contents (0.0005, 0.005, and 0.01 wt%), PI at room temperature, and sonication time for CNTs proper dispersion less than 1 minute. MWCNTs/CA nanocomposites membranes were prepared. MWCNTs were first functionalized by oxidation purification in a strong acidic medium to enhance their dispersion within the polymer matrix, and the success of the functionalization of MWCNTs was characterized using Fourier transform infrared (FTIR) spectroscopy. The nanocomposites morphologies were characterized by several methods by SEM and nitrogen adsorption. SEM images showed large networks of MWCNTs, randomly oriented and properly dispersed, with a significant decrease in the number of macrovoids development with CNT content increase at the same final thickness of the nanocomposites. This was verified by analysis of pore sizes (differential volumes and surface areas), which were found to decrease with the increase in CNT content. Nanocomposites permeations rates and salt rejection rates were investigated using 1000 ppm NaCl solution, and it was found that permeation improved significantly with the addition of CNTs, with the improvement being highest for lowest CNT content. Salt rejection was found to decrease with the presence of CNTs. However the decrease was minimal for low CNT contents. In this respect, it was possible to prepare CA-CNT nanocomposite membranes with improved permeation of 19.57 L/m2h, together with a minimal decrease of salt retention performance of 69.4% at 24 bars operating pressure. The membranes performance could be explained by membrane morphology (surface areas and porosity). |
| format | Thesis |
| id | oai:fount.aucegypt.edu:etds-2196 |
| institution | American University in Cairo (Egypt) |
| last_indexed | 2026-06-10T12:35:47.730Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from AUC Knowledge Fountain — bepress |
| publishDate | 2013 |
| publishDateRange | 2013 |
| publishDateSort | 2013 |
| publisher | AUC Knowledge Fountain |
| publisherStr | AUC Knowledge Fountain |
| record_format | dspace |
| source_str | AUC Knowledge Fountain — bepress |
| spelling | oai:fount.aucegypt.edu:etds-2196 Carbon nanotubes-cellulose acetate nanocomposites: membranes for water desalination El Badawi, Nouran Ashraf Cellulose acetate (CA) (Mw = 52,000 Da) membranes were prepared by phase inversion (PI) using acetone as a solvent. Investigation of different preparation conditions were carried out. The effect of membrane casting thickness, CA content, coagulation bath temperature (PI temperature), solvent evaporation, addition of a non-solvent (deionized water), and addition of multi-walled carbon nanotubes (MWCNTs) on membrane morphology and performance (permeation rates and salt rejection rates) were investigated. Membranes morphologies were studied using scanning electron microscopy (SEM). Membranes permeations rates and salt rejection rates were investigated using 1000 ppm NaCl solution. Optimum conditions for developing a CA based nanocomposites were attained, entailing 15 wt% CA content, 20 wt% H2O non-solvent additive, low functionalized CNTs contents (0.0005, 0.005, and 0.01 wt%), PI at room temperature, and sonication time for CNTs proper dispersion less than 1 minute. MWCNTs/CA nanocomposites membranes were prepared. MWCNTs were first functionalized by oxidation purification in a strong acidic medium to enhance their dispersion within the polymer matrix, and the success of the functionalization of MWCNTs was characterized using Fourier transform infrared (FTIR) spectroscopy. The nanocomposites morphologies were characterized by several methods by SEM and nitrogen adsorption. SEM images showed large networks of MWCNTs, randomly oriented and properly dispersed, with a significant decrease in the number of macrovoids development with CNT content increase at the same final thickness of the nanocomposites. This was verified by analysis of pore sizes (differential volumes and surface areas), which were found to decrease with the increase in CNT content. Nanocomposites permeations rates and salt rejection rates were investigated using 1000 ppm NaCl solution, and it was found that permeation improved significantly with the addition of CNTs, with the improvement being highest for lowest CNT content. Salt rejection was found to decrease with the presence of CNTs. However the decrease was minimal for low CNT contents. In this respect, it was possible to prepare CA-CNT nanocomposite membranes with improved permeation of 19.57 L/m2h, together with a minimal decrease of salt retention performance of 69.4% at 24 bars operating pressure. The membranes performance could be explained by membrane morphology (surface areas and porosity). 2013-02-01T08:00:00Z thesis application/pdf https://fount.aucegypt.edu/etds/1197 https://fount.aucegypt.edu/context/etds/article/2196/viewcontent/Thesis_20updated.pdf The author retains all rights with regard to copyright. The author certifies that written permission from the owner(s) of third-party copyrighted matter included in the thesis, dissertation, paper, or record of study has been obtained. The author further certifies that IRB approval has been obtained for this thesis, or that IRB approval is not necessary for this thesis. Insofar as this thesis, dissertation, paper, or record of study is an educational record as defined in the Family Educational Rights and Privacy Act (FERPA) (20 USC 1232g), the author has granted consent to disclosure of it to anyone who requests a copy. Theses and Dissertations AUC Knowledge Fountain nostructured materials Carbon |
| spellingShingle | nostructured materials Carbon El Badawi, Nouran Ashraf Carbon nanotubes-cellulose acetate nanocomposites: membranes for water desalination |
| title | Carbon nanotubes-cellulose acetate nanocomposites: membranes for water desalination |
| title_full | Carbon nanotubes-cellulose acetate nanocomposites: membranes for water desalination |
| title_fullStr | Carbon nanotubes-cellulose acetate nanocomposites: membranes for water desalination |
| title_full_unstemmed | Carbon nanotubes-cellulose acetate nanocomposites: membranes for water desalination |
| title_short | Carbon nanotubes-cellulose acetate nanocomposites: membranes for water desalination |
| title_sort | carbon nanotubes cellulose acetate nanocomposites membranes for water desalination |
| topic | nostructured materials Carbon |
| url | https://fount.aucegypt.edu/etds/1197 https://fount.aucegypt.edu/context/etds/article/2196/viewcontent/Thesis_20updated.pdf |
| work_keys_str_mv | AT elbadawinouranashraf carbonnanotubescelluloseacetatenanocompositesmembranesforwaterdesalination |