Integration of Experiments and Simulations for Molecular-Level Understanding of Membrane Fouling Mechanisms

文章摘要PI：Biaoxia MiProposal Nation：CBET-1034158机构：乔治华盛顿大学题目：分子水平理解膜污染机制的实验和模拟的集成本项目将结合分子模拟和多尺度实验表征，以实现对反渗透和纳滤(RO/NF)膜污染的分子水平的理解。反渗透/纳滤膜越来越多地被用于水的分离和淡化。然而，长期存在的胶体/有机污染问题严重制约了反渗透/纳滤膜的性能。开发有效的污染缓解策略和高度耐污染的膜依赖于对膜-污染相互作用的基本了解。然而，目前的实验研究试图了解膜性能对污染的影响，往往得出不一致的结论。此外，目前开发防污材料的努力大多是基于实验试错法，这是繁琐、昂贵和耗时的。因此，我们迫切需要一种更有效的方法来设计新的防污材料。为此，他们将：(1)开发一种新的适合于模拟污染物与膜表面之间的长期结合事件的新型混合分子模拟方法；(2)进行多尺度的实验表征，包括利用原子力显微镜测量纳米尺度的相互作用力，微观直接观察膜表面的污染物沉积，以及长期膜污染行为的宏观表征；(3)将实验测量和分子模拟相结合，实现了对膜污染的分子水平的理解，从而极大地促进了新型抗污染膜的设计。本研究的创新之处在于，它首次尝试将实验和分子模拟相结合，系统地揭示分子水平的膜-污染相互作用，这是仅靠实验或模拟方法无法完全理解的。这个项目将提供许多超越DLVO理论的膜-污染相互作用，如疏水/亲水相互作用，形态/化学异质性依赖的相互作用，官能团控制的特定相互作用，以及柔性链诱导的相互作用。这项研究的一个主要成果将是专门为膜污染研究设计的混合模拟工具箱。这个项目将通过两名在实验膜表征和分子模拟方面拥有共同专业知识的教员之间的跨学科合作来进行。因此，该项目将揭示反渗透/纳滤膜过程中污染现象的潜在机理，并有助于抗污染膜材料的系统设计。从分子水平了解膜污染行为将有助于开发下一代高抗污染的水分离膜。该研究还对膜法净水的能源效率和环境友好性方面产生了重大影响，产生了巨大的经济效益和社会效益。实验-模拟相结合的方法将成为各种膜过程基础研究的范例，包括压力驱动过程(如超滤和微滤)和渗透驱动过程(如正向渗透和压力减慢渗透)，以及其他更广泛的领域(如废水回用、食品加工、生物能源生产)。两名博士研究生将接受培训，几名本科生将积极参与拟议的项目。拟议研究的材料和结果将纳入本科生和研究生课程。拟议的研究活动还将影响现有大学联盟内邻近机构(包括两所历史上的黑人大学)代表性不足的学生。国际和平协会和联合国际和平协会之间的密切合作将激发批判性思维和创造性想法。研究成果将通过期刊出版物、会议报告、研究网站和研讨会以及在校园工程开放日期间向公众传播。PI在当地一所女子高中启动了一项教育推广计划，并将提供关于可持续水净化和回收的环境技术的讲座。

AbstractPI: Biaoxia MiProposal Number: CBET-1034158Institution: George Washington UniversityTitle: Integration of Experiments and Simulations for Molecular-Level Understanding of Membrane Fouling MechanismsThis project will integrate molecular simulation and multiscale experimental characterization to achieve a molecular-level understanding of the fouling of reverse osmosis and nanofiltration (RO/NF) membranes. RO/NF membranes are increasingly being used for water separation and desalination. However, the performance of RO/NF membranes is severely hampered by the long-standing problem of colloidal/organic fouling. Development of efficient fouling-mitigation strategies and highly foulingresistant membranes relies on the fundamental understanding of membrane-foulant interactions. However, current experimental studies attempting to understand the effects of membrane properties on fouling often draw inconsistent conclusions. In addition, current efforts to develop antifouling materials are mostly based on experimental trial-and-error, which is tedious, expensive, and time-consuming. Therefore, we urgently need a more efficient approach to designing new antifouling materials. Towards this goal, they will: (1) develop a novel hybrid molecular simulation approach that is specifically fit for simulating the long-time binding events between foulants and membrane surfaces; (2) conduct multiscale experimental characterization, including nanoscale interaction force measurement by atomic force microscopy, microscopic direct-observation of foulant-deposition on membrane surfaces, and macroscopic characterization of long-term membrane fouling behavior; and (3) integrate experimental measurements and molecular simulations to achieve a molecular-level understanding of membrane fouling, thus greatly facilitating the design of novel antifouling membranes.The novelty of the proposed study is that it represents the first-ever attempt to integrate experimental and molecular simulation efforts to systematically unveil the molecular-level membrane-foulant interactions, which cannot be fully understood by either experimental or simulation approaches alone. This project will offer keen insight into many membrane-foulant interactions beyond the DLVO theory, such as hydrophobic/hydrophilic interactions, morphological/chemical heterogeneity dependent interactions, functional-group-controlled specific interactions, and flexible-chain induced interactions. A major outcome of this research will be a hybrid simulation toolbox that is specifically designed for membrane fouling studies. This project will be conducted through an interdisciplinary collaboration between two faculty members with a joint expertise in experimental membrane characterization and molecular simulations. Thus, it is highly promising that the proposed project will unveil the underlying mechanisms of fouling phenomena in RO/NF membrane processes and facilitate systematic design of antifouling membrane materials.Molecular-level understanding of the membrane fouling behavior will help develop the next-generation highly fouling-resistant membranes for water separation. The research also has significant impacts on energy efficiency and environmental friendliness aspects of membrane-based water purification, leading to huge economic and societal benefits. The combined experimental-simulation approach will exemplify a paradigm of fundamental study on various membrane processes, including pressure-driven processes (such as ultrafiltration and microfiltration) and osmotically driven processes (such as forward osmosis and pressure-retarded osmosis), as well as in other broader areas (e.g., wastewater reuse, food processing, bioenergy production). Two PhD graduate students will be trained and several undergraduate students will be actively involved in the proposed project. Materials and outcomes of the proposed research will be integrated into both undergraduate and graduate courses. The proposed research activities will also impact underrepresented students at neighboring institutions (including two historically black universities) within an existing university consortium. The close collaborations between the PI and co-PI will stimulate critical thinking and creative ideas. Research findings will be disseminated through journal publications, conference presentations, research websites, and seminars, as well as to the general public during the on-campus Engineering Open House. The PI has initiated an educational outreach program at a local girls-only high school and will offer lectures on the environmental technologies for sustainable water purification and reclamation.