Abstract

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).

Department

Chemistry Department

Degree Name

MS in Chemistry

Date of Award

2-1-2013

Online Submission Date

January 2013

First Advisor

Ramadan, Adham Zaki

Committee Member 1

Ragai, Jehane

Committee Member 2

Abel Ghani, Samir

Document Type

Thesis

Extent

142 p.

Library of Congress Subject Heading 1

Saline water conversion.

Library of Congress Subject Heading 2

notubes.

Rights

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.

IRB

Not necessary for this item

Comments

I would like to deeply thank my advisor and mentor Dr. Adham Ramadan and my co-advisor Dr. Amal Esawi for giving me the time, effort, and guidance to carry out this project. Their encouragement, patience, and constructive feedbacks were such a positive energy that kept me going until seeing this through. Their moral support on all matters, academic and persol significantly affected my life as a whole, not only my research skills. No words will ever fulfill my gratitude, and I am really honored to have them as my advisors. Thank you. I would also like to express my deep appreciation for the Youssef Jameel Science and Technology Research Center (YJSTRC) for their fincial support, through a full fellowship, over my years of study for the Masters degree in Chemistry. I cannot fail to mention Dr. Sherif Sedky, the former director of YJSTRC, who always believed in me, and Dr. Ehab Abdel Rahman, the current director of YJSTRC, who always encouraged me. This has been a wonderful research experience in a well renowned facility. I also want to thank Eng. Rami Wasfi, Dr. Omar Zaki, and Eng. Ehab Salama, for training me on how to use some of the equipment in the research center, for, without them, I wouldn’t have been able to carry on the work done. I also wish to thank the faculty and staff members of the Chemistry Department who have always had their doors wide open for all students who needed help in any matter. I would specially like to thank Dr. hed Yaqoub for her time in aiding me with many of the calculations carried out. The Chemistry Department has been my second home for more than eleven years. It is the place which expanded my horizon to new possibilities, and offered me new chances of education and achievements. It is the place where I have a real sense of belonging. I would also like to thank Dr. Mohammed Morsi, Mechanical Engineering Department, for helping me carry out the permeation measurements. His time and effort are greatly appreciated. On more persol bases, I would love to thank my parents for being my lighthouse when life darkened the most. Their unconditiol love and devotion humble me. No daughter can ever have better parents, for they are, and forever will be my comfort zone. I would also love to thank my best friends Haidy Youssef, Noha Khattab, Samaa waar, Di Nemr, and Ayaat Mahmoud for being there for me all the time and never letting me down. Last, I wish to express my gratefulness, love, and admiration to my Tahrir buddies: Hany el Kady, Ayaat Mahmoud, Di Nemr, Mahmoud Bizzari, Samaa waar, Essam Omar, da shaat, deem Gawad, Ramy el Gohari, Haidy Youssef, Hani Tawfeek, and Amr Zeid. These people are treasure. They had my back, cherished my life over theirs, and helped me survive the past two years both psychologically and physically. I owe them more than I can possibly pay back, and I am really blessed to have them in my life. Thank you all for an overwhelming wonderful and challenging experience.

Share

COinS