Collaborative Research: Coupled effects of particle shape/flexibility and pore morphology on membrane rejection: theory and experiment

建议编号：1604715(牵头)/1605088 PI：Baltus，R.E./Cherlam，S.合作研究：颗粒形状/柔韧性和孔形态对膜截留的耦合影响：理论和实验这项研究的动机在于，到2025年，预计将有近20亿人生活在缺水地区。这些驱动因素表明，需要先进的水和废水处理技术来缓解日益增长的用水需求。低压液-固膜分离技术，如微滤和超滤，直接去除难以消毒的寄生虫，如贾第虫和隐孢子虫，以及大多数细菌、浑浊和其他胶体物质。然而，微滤器和超滤器在去除病毒和一些细菌方面并不有效。这项研究的总体目标是考察非理想的孔几何形状和颗粒形状以及弹性对多孔膜对微生物截留的影响。这个合作研究项目将进行数学建模和实验工作，以定量检查更接近真实世界分离的复杂系统。该项目产生的结果将对微滤和超滤系统的优化设计以及与水和废水处理以及食品、生物技术和制药业务相关的实际应用具有重要意义。更广泛的教育影响包括开展面向德克萨斯州大学站和纽约州波茨坦邻近社区的小学、初中和高中的科学推广活动，以吸引代表不足的少数群体进入STEM领域。目前可用的膜系统设计策略是基于简单的孔几何形状和微生物形状。因此，它们不能完全解释在实践中观察到的不完全的微生物去除。这一合作项目将产生基础知识，以表征拖尾病毒、丝状病毒、可变形细菌和刚性合成纳米棒在具有曲折相互连接的孔网络的多孔膜上的受阻对流。该项目将实验和理论工作紧密结合在一起。该项目将侧重于使用具有毛细管孔的低压膜以及具有复杂孔形态的膜系统来分离尾部和柔性的病毒和细菌颗粒。这项研究的技术影响的一个例子是，它正在解决消除拖尾病毒的困难，拖尾病毒是环境中最丰富的生物体之一，已被证明可以穿透所谓的无菌过滤器。这项研究将检查柔性颗粒是否能够绕过毛孔弯曲，以及缺乏坚硬细胞壁的细菌是否可以挤过毛孔。为了从理论上检验颗粒的形状和弹性，我们将建立单个圆柱孔中颗粒传输的详细模型。具体地说，病毒和细菌的非球形和灵活性的物理学将被纳入其中。验证这些模型预测的实验将使用径迹蚀刻薄膜进行。为了检查膜形态的影响，包括孔的相互连通性，将进行2D渗透测量，并使用为描述这些系统而开发的模型来解释。这个项目将产生对复杂的孔几何形状和微生物特征的作用的定量理解，这些因素支配着微生物从多孔膜中的排斥。纳入这些考虑因素将改进现有的过滤模型，以便更准确地描述现实世界膜分离中的排斥。

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.