CAREER: SusChem: Multiscale Modeling for Fluid Separation Across Two-Dimensional Molecular Sieves and Student-Centered Course Reform

科罗拉多大学博尔德分校的Joel Eaves由化学学部的化学理论、模型和计算方法项目资助，为下一代水净化策略开发基本原理、方法和模型。水安全是一个新出现的问题，需要开发获取饮用水的新技术。新颖的、原子薄的二维晶体在海水淡化应用中显示出巨大的前景，计算机模拟可能是在这一努力中进行计算发现的有效工具。但是由于目前在知识和方法上的差距，模拟在其适用性和范围上基本上是有限的，并且无法可靠地描述微观运动和相互作用如何与反渗透的优点相关联。Eaves和他的研究小组通过开发概念、理论和计算工具来解决这些差距，这些工具在模拟和理解多孔二维晶体的流体分离方面显着扩展了计算可预测性和实用性。此外，作为该职业奖的一部分，Eaves正在分别在研究生和本科阶段开发以学生为中心的基于问题的学习（PBL）教学法。PBL是一种通过让学生参与现实世界的问题来促进主动学习的教学法。Eaves计划开发几个PBL模块，使用一些计算工具作为虚拟实验室，以鼓励学生主导的提问和好奇心，这是科学研究的特征。PBL模块和开发的评价工具都将在网上传播。多孔二维晶体是薄半透膜的极限，但同样的长度尺度差异使它们对反渗透应用具有吸引力，也使它们难以用理论和模拟来描述。利用一系列测试系统和模型，Eaves和同事研究了流体在低流量状态下的分离和通过原子薄二维晶体的过程，其中近平衡理论适用，而在高流量状态下，系统本质上是不平衡的，当前的模拟方法是有限的。他们正在测试一种假设，即膜的疏水性可以通过电掺杂在石墨烯中改变，对水的吞吐量具有可测量和可控的影响。在接近平衡的情况下，重点是将水通量和离子排斥与平衡时的自发波动联系起来的随机理论，并研究水通过和离子排斥的反应坐标和过渡态。在平衡之外，Eaves正在开发新的介观模拟方法，以弥合原子模拟与更大尺度流体动力学和集体变量之间的差距。此外，他计划研究除功能化多孔石墨烯外用于海水淡化的二维晶体。

Joel Eaves of the University of Colorado at Boulder is funded by the Chemical Theory, Models and Computational Methods program in the Chemistry Division to develop fundamental principles, methods, and models for next-generation water purification strategies. Water security is an emerging problem that necessitates the development of new technologies for obtaining potable water. Novel, atomically thin two-dimensional crystals show great promise in water desalination applications, and computer simulations might be effective tools for computational discovery in this endeavor. But with current gaps in both knowledge and methodology, simulations are fundamentally limited in their applicability and scope, and are unable to reliably describe how microscopic motions and interactions connect to figures of merit for reverse osmosis. Eaves and his research group address these gaps by developing concepts, theories, and computational tools that significantly extend computational predictability and utility in modeling and understanding fluid separation across porous two-dimensional crystals. In addition, as part of this CAREER award, Eaves is developing student-centered problem-based learning (PBL) pedagogies at the graduate and undergraduate levels, respectively. PBL is a pedagogy that facilitates active learning by engaging students with real world problems. Eaves plans to develop several PBL modules using some of the computational tools proposed as a virtual laboratory to encourage the kind of student-directed questioning and curiosity that characterizes scientific research. Both the PBL modules and evaluative tools developed will be disseminated over the web.Porous two-dimensional crystals are the ultimate limit in thin semipermeable membranes, but the same length scale disparity that makes them attractive for reverse osmosis applications also makes them challenging to describe using theory and simulation. Using a series of test systems and models, the Eaves and coworkers study fluid separation and passage through atomically thin two-dimensional crystals in regimes of low flow, where near-equilibrium theories apply, and in regimes of high flow, where the system is intrinsically out of equilibrium and current simulation methods are limited. They are testing the hypothesis that the hydrophobicity of the membrane, which can be altered in graphene by electrical, doping, has a measurable and controllable effect on water throughput. In the near equilibrium case, the focus is on a stochastic theory to relate water throughput and ion rejection to spontaneous fluctuations at equilibrium and investigate the reaction coordinates and transition states for water passage and ion rejection. Away from equilibrium, Eaves is developing novel mesoscopic simulation methods that bridge the gap between atomistic simulations and larger scale hydrodynamic and collective variables. In addition, he plans to investigate two-dimensional crystals for water desalination applications other than functionalized, porous graphene.