Type
Text
Type
Dissertation
Advisor
Chu, Benjamin | Lauher, Joseph | Khalifah, Peter | Hsiao, Benjamin S. | Mahajan, Devinder.
Date
2015-08-01
Keywords
filtration, membrane, polymer | Chemistry
Department
Department of Chemistry.
Language
en_US
Source
This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.
Identifier
http://hdl.handle.net/11401/77164
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
A thin-film nanofibrous composite (TFNC) membrane system for nanofiltration (NF) with substrates entirely fabricated by fibers was prepared. Water-channel structure was formed at the interface between the polymer barrier layer and the ultrafine cellulose nanofibers (CNs) in the supporting layer, demonstrating the advantages of using a CN substrate over other conventional ones. Both manual coating and slot-die coating were applied for membrane preparations. The resulting membrane performance showed that the slot-die coating method could produce better performance membranes than the manual coating method. With the optimized formulations and coating conditions, TFNC NF membranes coated by the slot-die method had a higher flux, of ~100% more than a reference commercial NF membrane, (NF 270, Filmtec), but with the same salt rejection ratio. This is because of the slot-die coating method could effectively control the barrier layer coating thickness, thus better control the pore size distribution. Two interfacial polymerization pathways (termed IP and IP-R), regarding the arrangement of the aqueous and organic phases, were investigated on CN and on electrospun scaffolds. It was found that the interfacial polymerization with the aqueous phase above the organic phase (IP-R) yielded better filtration performance, i.e. | IP-R based membranes exhibited a higher MgCl2 rejection than IP based membranes, probably because of smaller average pore size in the former. Finally, preparation of TFNC membranes for reverse osmosis (RO) was formulated by using different inert additives during interfacial polymerization, such as triethylamine (TEA), 1-octyl-3-methylimidazolium chloride (OMIC), camphor-10-sulfonic acid (CSA), isopropyl alcohol (IA) and o-aminobenzoic acid (o-ABA) and sodium lauryl sulfate (SLS). Among all the additives, 1-octyl-3-methylimidazolium chloride (OMIC) (an ionic liquid that is soluble in the aqueous phase), was found to be able to achieve the best RO membrane performance. The resulting TFNC RO membranes based on the CN scaffold showed higher A values (water transport coefficient) and lower B values (salt transport coefficient) than those without it. | 164 pages
Recommended Citation
Wang, Xiao, "Thin-film Nanofibrous Composite Membranes by Interfacial Polymerization for Water Purification" (2015). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 3000.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/3000