GOALI: In situ generation of two phase flows to eliminate membrane concentration polarization and fouling

PI姓名：Darrell Velegol提案编号：1705278膜技术，特别是反渗透（RO），现在处于海水、微咸水和废水等低质量水源水净化的最前沿。 本项目的目的是通过在膜表面产生氧气来阻止膜上生物膜的生长，从而最大限度地减少膜污染。 生物结垢对脱盐膜性能的负面影响最大。 这项基础研究有可能通过显着减少膜的能源使用和增加其使用寿命来改变膜的性能。 这些基本原理将有助于开发出可扩展的、商业上可行的解决方案，并改善市政和工业水处理，以满足日益增长的国家饮用水需求。许多研究都集中在通过预处理提高反渗透效率、最大限度地减少浓差极化（CP）和减轻结垢。 目前的方法还没有克服这个问题，在一个可行的方式，特别是浓差极化，但是，没有研究已经报告的应用程序中产生的微气泡原位干扰CP边界层。 假设是在膜表面催化产生微气泡将产生局部微观混合，这将显著减少浓差极化和颗粒-细菌-有机物污染。 为了测试总体假设并满足目标，必须回答三个重要的基本问题，并形成本研究的知识价值：1）给定特定催化剂类型、催化剂负载分数、过氧化氢（H2 O2）剂量分布和局部压力（即，必须超过亨利定律溶解度）？2)对于一个给定的微气泡的生产率和尺寸分布，什么是增加的水流出物由于不同的机制，微混合的浓差极化，和剥离膜污染的物种？和3）对于给定的微泡生产速率，在避免膜损伤的生产水平下，使用所产生的氧化剂（活性氧物质）对生物膜形成微生物的消毒能力是多少？ 该方法是将催化剂掺入膜组件（膜表面或间隔物）中，然后在膜的操作期间，注入H2 O2或其他反应物的脉冲，其将在膜表面产生微泡。 这项工作的主要优点是随着时间的推移通过膜的水通量增加。 这项提案的更广泛影响集中在博士教育上。学生（包括与我们的NSF GOALI合作伙伴陶氏化学公司的实习）和本科生，以及技术商业化（与陶氏化学公司合作）。 产生微泡和产生局部微观混合可以在商业规模上实现。 博士本科教育以及实习和创业培训将成为学生体验的一部分。

PI Name: Darrell VelegolProposal Number: 1705278Membrane technologies, especially reverse osmosis (RO), are now at the forefront of water purification from lower-quality water sources such as seawater, brackish water, and wastewater. The objective of this project is to minimize membrane fouling by producing oxygen at the membrane surface to impede the growth of biofilms on the membrane. Biofouling has the largest negative impact on desalination membrane performance. This fundamental research has the potential to transform membrane performance by significantly decreasing the energy use of membranes and increasing their usable lifetime. The fundamental principles learned are anticipated to lead to solutions that are scalable and commercially viable and can improve municipal and industrial water treatment to help meet the growing national demand for potable water.Numerous efforts have focused on improving RO efficiency by pretreatment, minimizing concentration polarization (CP), and mitigating fouling. Current methods have not overcome the problem in a feasible manner, especially for concentration polarization; however, no study has been reported on the application of microbubbles generated in situ to disturb the CP boundary layer. The hypothesis is that catalytically generating microbubbles at a membrane surface will produce localized micromixing, which will significantly reduce both concentration polarization and particle-bacteria-organic fouling. To test the overall hypothesis and meet the objective, three important fundamental questions must be answered, and form the intellectual merit of this research: 1) What is the rate of microbubble formation, and the microbubble size distribution, given a particular catalyst type, catalyst loading fraction, hydrogen peroxide (H2O2) dosing profile, and local pressure (i.e., must exceed Henry's law solubility)? 2) For a given microbubble production rate and size distribution, what is the increase in water effluent due to the different mechanisms of micromixing for concentration polarization, and liftoff for membrane fouling species? and 3) For a given microbubble production rate, what is the disinfection capacity for biofilm-forming microorganisms using the produced oxidant (reactive oxygen species), at production levels that avoid membrane damage? The approach is to incorporate catalysts in the membrane module (either membrane surface or spacers), and then during the operation of the membrane, to inject pulses of H2O2 or other reactants that will produce microbubbles at the membrane surface. A primary figure of merit for this work is an increased water flux through the membrane over time. The broader impacts of this proposal focus on educating Ph.D. students (including internships with Dow Chemical, our NSF GOALI partner) and undergrads, as well as technological commercialization (with partner Dow Chemical). Producing microbubbles and generating localized micromixing could be achieved at commercial scale. Ph.D. and undergrad education as well as internships and entrepreneurship training will form part of the student experience.