A collaborative experimental program in fundamental research and education is proposed to address critically important problems in the area of polymer membranes for water purification. Polymer membrane technology, such as ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) is becoming dominant in water purification technology, due largely to its energy efficiency relative to conventional technologies such as distillation. When commercially available UF, NF and RO membranes are exposed to mixtures of salt, emulsified oil droplets, and other particulate matter, their lifetime of effective use decreases catastrophically due to a largely irreversible reduction in permeate flux as a result of membrane fouling by the organic contaminants. The PI recently initiated preliminary experiments to evaluate the fouling performance (in Freeman group) of commercial PVDF UF membranes coated with amphiphilic graft copolymers prepared in Emrick group. These graft copolymers are composed of polyolefin backbones, which provide mechanical integrity needed in membrane applications, and poly(ethylene glycol) (PEG) grafts, to provide the hydrophilicity needed to enable high water flux. The connectivity between the polyolefin backbone and PEG grafts is made with ether bonds, so as to provide long-term hydrolytic stability of the polymer in these aqueous-based applications. Moreover, the graft copolymer design allows integration of functionality into the polymer for cross-linking chemistry that will be used to give robust coatings on a variety of membranes, and also to cross-link the polymer coating into the underlying membrane support. Early evaluations of these PEGylated graft copolymers as fouling-resistant coatings on commercial membranes are promising and also present challenges to the PI that are deemed exceptionally worthy of PhD research and education. The research is proposed in a collaborative program to most effectively advance the science, as the engineering and synthetic chemistry aspects both play critically important roles and are best conducted in a collaborative fashion.
The broader impact of advances in water purification membrane technology cannot be overstated, as the increase in global population and societal development, combined with the continuously shrinking fresh water supply, place water at the forefront of global concern. Innovative advances in membrane technology can be accelerated through collaborative research, and the PI established ties with membrane manufacturers, as well as industrial-based support mechanisms for academic research, will lead to rapid integration of discoveries towards development and commercialization. The education of the students involved in the research stands to gain tremendously from the collaborative aspect. Regular exchange of students between Amherst and Austin will facilitate this collaboration. Moreover, in accord with the prior activities of the PIs, research on water purification membranes will permeate into their mentoring of undergraduates and high school teachers through the Research Experience for Undergraduates (REU) and Research Experience for Teachers (RET) programs.
