CAREER: Locally Enhanced Electric Field Treatment (LEEFT) for Chemical-Free Water Disinfection

全世界有8亿多人没有足够的安全饮用水供应。在许多由饮用水处理厂提供服务的地区，氯被用来杀死有害微生物。然而，氯化会产生已知的人类致癌物。一项能够向没有足够饮用水供应的地区提供服务点处理的创新技术是局部增强电场处理（LEEFT）。低电压下操作的LEEFT处理时间很短，只需几秒钟，就能达到高消毒效果。left还具有相对便宜、不含化学物质、坚固耐用和易于操作的优点。在这个项目中，PI将研究如何在左左处理过程中杀死饮用水中的有害微生物。这项工作的目标是发展在饮用水处理中广泛采用的left，以保护公众健康。该项目的教育计划侧重于在高中、本科和研究生阶段培养未来的环境工程领导者。这一努力将得到公众宣传的补充，以提高对水安全的认识，并使公众更好地准备应对因意外自然灾害而导致的供水中断。LEEFT是一种物理处理过程，旨在利用强电场破坏细胞膜，从而使饮用水中的病原体失活。安装在LEEFT器件中的电极通常采用一维纳米结构进行修饰，因此电场不是均匀的，而是在纳米结构尖端附近局部增强。该项目将系统地研究细菌在LEEFT过程中的行为，有四个具体目标：1)获得适合机制研究的LEEFT平台；2)了解LEEFT过程中细菌失活的机制；3)揭示LEEFT设备中细胞运输的过程；4)开发用于性能预测的LEEFT机制模型。核心假设是，在LEEFT过程中，细菌通过流体动力、电泳和介电泳力的组合被输送到具有强电场的区域，然后主要由于不可逆的电穿孔而灭活。本项目中的一些平台将构建在使用微机电系统（MEMS）技术制造的芯片实验室设备上。left实验将在各种条件下进行，例如电极材料、电脉冲频率、混合条件和模型细菌。该模型将基于COMSOL Multiphysics的实验结果建立，COMSOL Multiphysics是一种使用先进数值方法分析、解决和模拟物理问题的软件。综合教育活动包括一个名为WE-HUG（高中、本科生和研究生的水安全教育和培训）的项目，在这个项目中，一个由高中教师和学生组成的垂直团队被招募来开发和交付反映项目科学和工程方面的教育模块。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Over 800 million people worldwide do not have adequate supply of safe drinking water. In many areas serviced by drinking water treatment plants, chlorine is used to kill harmful microbes. However, chlorination can produce chemicals that are known human carcinogens. An innovative technology that can provide point-of-service treatment to areas without adequate drinking water supply is locally enhanced electric field treatment (LEEFT). High disinfection has been achieved by LEEFT operated at low voltages with a short treatment time of a few seconds. LEEFT has the added benefits of being relatively inexpensive, chemical-free, robust, and easy to operate. In this project, the PI will study how harmful microbes in drinking water are killed during LEEFT treatment. This work has the goal of developing LEEFT for wide-scale adoption for drinking water treatment to protect public health. The educational plan of this project focuses on training future environmental engineering leaders at the high school, undergraduate, and graduate level. This effort will be complimented by public outreach to increase awareness of water safety and better prepare the public to respond to disruptions in water supply due to unexpected natural disasters.LEEFT is a physical treatment process that aims to utilize a strong electric field to disrupt cell membranes and thus inactivate pathogens in drinking water. The electrodes installed in a LEEFT device are typically modified with one-dimensional nanostructures so that the electric field is not uniform but enhanced locally near the tips of the nanostructures. This project will systematically investigate the behavior of bacteria during LEEFT with four specific objectives: i) obtaining LEEFT platforms that are suitable for mechanistic study, ii) understanding the mechanisms for bacteria inactivation during LEEFT, iii) revealing the processes for cell transportation in LEEFT devices, and iv) developing a mechanistic model of LEEFT for performance prediction. The core hypothesis is that during LEEFT, bacteria are transported to the regions with strong electric field by a combination of hydrodynamic-, electrophoretic-, and dielectrophoretic-forces, and then inactivated primarily due to irreversible electroporation. Some platforms in this project will be constructed on lab-on-a-chip devices fabricated using micro-electro-mechanical-systems (MEMS) technologies. LEEFT experiments will be performed under various conditions, e.g., electrode materials, frequency of the electric pulses, mixing conditions, and model bacteria. The model will be built based on experimental results using COMSOL Multiphysics, a software using advanced numerical methods to analyze, solve, and simulate physics-based problems. The integrated educational activities involve a program entitled WE-HUG (Water-safety Education and training for High school, Undergraduate, & Graduate students), where a vertical team of high school teachers and students are recruited to develop and deliver education modules that reflect the scientific and engineering aspects of the project.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.