Collaborative Research: Coupled effects of particle shape/flexibility and pore morphology on membrane rejection: theory and experiment
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Proposal Numbers: 1604715 (Lead)/1605088 PIs: Baltus, R.E./Chellam, S.Collaborative Research: Coupled effects of particle shape/flexibility and pore morphology on membrane rejection: theory and experimentThe motivation for this research lies in the fact that by the year 2025, nearly 2 billion people are projected to live in areas of water scarcity. These drivers point to the need for advanced water and wastewater treatment technologies to alleviate ever-increasing water demand. Low-pressure liquid-solid membrane separation technologies such as microfiltration and ultrafiltration directly remove difficult-to disinfect parasites such as Giardia and Cryptosporidium, along with most bacteria, turbidity, and other colloidal materials. However, micro- and ultrafilters are not effective in removing viruses and some bacteria. The overall goal of this research is to examine the impact of non-ideal pore geometry and particle shape and flexibility on microbial rejection by porous membranes. This collaborative research project will perform both mathematical modeling and experimental work to quantitatively examine complex systems that more closely represent real-world separations. Results generated from this project will be important for the optimal design of micro- and ultrafiltration systems and for practical applications related to water and wastewater treatment and food, biotechnological, and pharmaceutical operations. Educational broader impacts include the development of science outreach activities geared towards elementary, middle, and high schools in neighboring communities in College Station, TX and Potsdam, NY to attract underrepresented minorities into STEM fields.Currently available membrane system design strategies are based on simple pore geometries and microbial shapes. Consequently, they cannot fully explain incomplete microbial removal observed in practice. This collaborative project will generate fundamental knowledge to characterize the hindered convection of tailed viruses, filamentous viruses, deformable bacteria, and rigid synthetic nanorods across porous membranes with tortuous interconnected pore networks. The project tightly integrates the experimental and theoretical efforts. The project will focus on separations of tailed and flexible viral and bacterial particles using low-pressure membranes with capillary pores as well as membrane systems with complex pore morphology. One example of the technological impact of this research is that it is addressing the difficulty in removing tailed viruses that are among the most abundant organisms in the environment and have been shown to penetrate so-called sterile filters. The research will examine whether flexible particles will be able to navigate around pore bends and whether bacteria that lack rigid cell walls can squeeze through pores. To theoretically examine particle shape and flexibility, detailed models of particle transport in a single cylindrical pore will be developed. Specifically, the physics of the non-spherical shape and flexibility of the viruses and bacteria will be incorporated. Experiments to validate these model predictions will be performed using track-etched membranes. To examine effects of membrane morphology including pore interconnectivity, 2D permeation measurements will be performed and interpreted using models developed to describe these systems. This project will generate a quantitative understanding of the role of complex pore geometries and microbial characteristics that govern rejection of microorganism from porous membranes. Incorporating such considerations will improve existing filtration models to more accurately describe rejection in real-world membrane separations.