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Title:Development and characterization of dendrimeric NF/RO polyamide membranes
Author(s):Martinez Saenz de Jubera, Ana
Director of Research:Mariñas, Benito J.
Doctoral Committee Chair(s):Mariñas, Benito J.
Doctoral Committee Member(s):Moore, Jeffrey S.; Cahill, David G.; Nguyen, Thanh H.
Department / Program:Civil & Environmental Eng
Discipline:Environ Engr in Civil Engr
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Membrane filtration
Reverse Osmosis
Polyamide active layer
Rutherford backscattering spectrometry
Solute rejection
Abstract:Membrane technology has emerged as an alternative to more conventional water treatment processes. A major factor behind this emergence is that nanofiltration (NF) and reverse osmosis (RO) membranes are able to remove a broad spectrum of water contaminants including microorganisms, colloids, organic molecules, and inorganic ions in a single treatment step. Most commercial NF and RO membranes have a thin-film active layer, of approximately 50 to 200 nm that acts as the barrier for contaminant rejection. The active layer of most commercially available NF/RO membranes is a polyamide (PA) thin film made by interfacial polymerization. Although other polymers have been used as NF/RO membrane active layers such as sulfonated polyethersulfone (SPES) and various polyvinyl alcohol (PVA) derivatives, polyamide remains the most common material. Despite the fact that NF and RO membranes have been proven to be efficient techniques to produce clean water from a majority of water sources, RO energy requirements limit clean water productivity; and low pressure NF membranes cannot remove a number of contaminants which pose a risk to human health such as neutral arsenic (III), and certain pharmaceuticals and pesticides. The work here presented aims i) to incorporate polyamide dendrimers to the membrane fabrication process, with the goal of optimizing the performance of commercial NF membranes, ii) to design a new generation of polyamide active layers with a broader range of structural properties compared to those of commercial membranes, iii) and to investigate the effect that active layer physicochemical properties have on membrane performance, to tailor new types of membranes. A methodology was developed to covalently attach amine terminated dendrimers to carboxylic groups on the membrane surface with 2 coupling reagents. This approach was used to modify commercial NF membranes to achieve enhancements in solute rejection performance while maintaining the water permeability of the membranes. An approach was also developed to synthesize novel aramide dendrimer active layers by interfacial polymerization of amine-terminated dendrimers with trimesoyl chloride. A variety of membranes with performance within the range of commercial NF and RO membranes and even superior to state-of-the-art RO performance was obtained by changing parameters in the interfacial polymerization process. Characterization results revealed that the structure, thickness, and pore distribution of the dendrimeric membranes were different from the commercial membranes; those differences were correlated to changes observed in performance.
Issue Date:2014-05-30
Rights Information:Copyright 2014 Ana Martinez Saenz de Jubera
Date Available in IDEALS:2014-05-30
Date Deposited:2014-05

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