CAREER: Harnessing Mineralogy and Polymer Science to Elucidate Mechanisms and Mitigation Strategies for Mineral Scaling in Membrane Desalination

在气候迅速变化和水资源日益短缺的情况下，反渗透(RO)等基于膜的技术正越来越多地被用于在美国和世界范围内提供清洁水。目前，反渗透技术是从各种受损水源中提取和回收清洁水的最佳商业技术，这些水源包括海水、内陆微咸水和城市/工业废水。然而，反渗透膜表面无机结垢的形成和沉淀严重限制了反渗透膜的水回收，并对反渗透海水淡化和水回用厂生产的水的整体工艺效率和成本产生了不利影响。与有机/生物膜污染相比，反渗透膜表面无机结垢的形成和沉淀机理尚不清楚，因为它们涉及复杂的化学反应和聚合物-矿物-水界面的成核现象。这个职业项目的首要目标是促进对反渗透膜表面矿物结垢的基本了解。该项目的成功完成将通过发展新的基础知识来促进更有效和更具成本效益的解决方案的开发和实施，以控制和减轻反渗透海水淡化和水再利用系统中的矿物结垢，从而造福社会。通过学生教育和培训，包括指导科罗拉多州立大学的一名研究生和一名本科生，将进一步造福社会。膜结垢仍然是一个重要且尚未解决的挑战，它限制了商业反渗透(RO)海水淡化和水再利用工厂的水回收和整体系统效率。在对反渗透膜结垢的基本认识上，仍然存在着重要的知识空白。首先，控制反渗透膜中矿物结垢程度的关键物理/化学过程和因素还不是很清楚。其次，利用表面改性来减轻反渗透膜中的矿物结垢只取得了有限的成功。第三，缺乏基本的知识和原则来指导阻垢剂的设计，以减轻反渗透膜中无定形二氧化硅垢的形成和沉淀。这份职业建议书将解决这些关键的知识差距。这项研究的指导假设是，聚合物作为反渗透膜表面改性剂或阻垢剂，可以通过改变膜-水界面上结垢事件的热力学和动力学以及随后新生的矿垢附着到膜表面来控制矿物结垢的程度。这项研究的两个关键目标是：(1)表征和揭示结垢成核热力学、动力学和矿物膜亲和力对反渗透膜结垢的影响；(2)建立结构-性能-性能关系，指导和指导抗结垢反渗透膜和聚合物阻垢剂的设计，以减少和防止反渗透膜结垢。该项目的成功完成有可能通过产生新的基础知识来促进制定更有效的战略来控制和减轻反渗透海水淡化和水再利用厂的膜垢，从而产生变革性的影响。为了实现这一职业项目的教育和培训目标，首席调查员(PI)将与科罗拉多州立大学(CSU)美国原住民STEM研究所合作，为美国原住民高中生开发和实施讲座和动手实验，以了解与水可持续发展相关的关键科学和工程挑战，包括海水和微咸水的淡化。此外，PI计划与CSU工程学院的ENpower Bridge项目合作，鼓励和招收代表不足的群体的学生继续环境工程本科/研究生教育。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Membrane-based technologies such as reverse osmosis (RO) are increasingly being utilized to provide clean water in the United States and worldwide under a rapidly changing climate and growing water scarcity. Currently, RO is the best available commercial technology for extracting and recovering clean water from a wide range of impaired water sources including seawater, inland brackish water, and municipal/industrial wastewater. However, the formation and precipitation of inorganic scales at the surface of RO membranes severely limit their water recovery and adversely impact the overall process efficiency and cost of water produced by RO desalination and water reuse plants. Compared to organic/biological membrane fouling, the mechanisms of formation and precipitation of inorganic scales at RO membrane surfaces are poorly understood as they involve complex chemical reactions and nucleation phenomena at polymer-mineral-water interfaces. The overarching goal of this CAREER project is to advance the fundamental understanding of mineral scaling at the surface of RO membranes. The successful completion of this project will benefit society through the development of new fundamental knowledge to advance the development and implementation of more efficient and cost-effective solutions to control and mitigate mineral scaling in RO desalination and water reuse systems. Further benefits to society will be achieved through student education and training including the mentoring of a graduate student and an undergraduate student at Colorado State University.Membrane scaling remains an important and unresolved challenge that limits the water recovery and overall system efficiency of commercial reverse osmosis (RO) desalination and water reuse plants. There are still critical knowledge gaps in the fundamental understanding of RO membrane scaling. First, the key physical/chemical processes and factors that control the extent of mineral scaling in RO membranes are not well understood. Second, the utilization of surface modification to mitigate mineral scaling in RO membranes has met with only limited success. Third, there is a lack of fundamental knowledge and principles to guide the design of antiscalants to mitigate the formation and precipitation of amorphous silica scales in RO membranes. This CAREER proposal will address these critical knowledge gaps. The guiding hypothesis of the proposed research is that polymers used as RO membrane surface modifiers or antiscalants can control the extent of mineral scaling by altering the thermodynamics and kinetics of scale nucleation events at membrane-water interfaces and the subsequent attachments of nascent mineral scales to membrane surfaces. Two key goals of the research are to: (1) Characterize and unravel the roles of scale nucleation thermodynamics, kinetics, and mineral-membrane affinity on the extent of RO membrane scaling and (2) Develop structure-property-performance relationships to guide and inform the design of scaling-resistant RO membranes and polymeric antiscalants to minimize and prevent RO membrane scaling. The successful completion of this project has the potential for transformative impact through the generation of new fundamental knowledge to advance the development of more effective strategies to control and mitigate membrane scaling in RO desalination and water reuse plants. To implement the educational and training goals of this CAREER project, the Principal Investigator (PI) will work with the Native American STEM Institute of Colorado State University (CSU) to develop and implement lectures and hands-on experiments for Native American high school students to learn about the critical science and engineering of challenges around water sustainability including the desalination of seawater and brackish water. In addition, the PI plans to partner with the ENpower Bridge program of CSU’s Engineering College to encourage and recruit students from underrepresented groups to pursue undergraduate/graduate education in Environmental Engineering.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.