Modeling Adsorption in Complex Porous Structures: Equilibrium, Hysteresis and Dynamics

Peter A.蒙森，马萨诸塞州-阿默斯特大学“模拟复杂多孔结构中的吸附：平衡，滞后和动力学“这项研究将使用分子模拟来了解具有复杂孔结构的多孔材料中的流体行为。主要目标是更精确地理解分子相互作用和多孔材料结构在几个长度尺度上的组合效应如何产生特定种类的吸附行为。这种理解对于分离和催化等重要应用以及多孔材料表征至关重要。动态和平衡建模技术的结合是该项目的一个中心特征。两个互补的研究领域被规划。在第一个领域，PI关注的是复杂孔隙结构中吸附/脱附的粗粒度晶格模型。这项工作的目标是开发一个框架，用于理解吸附测量和多孔材料的微观结构之间的关系-特别是在毛细凝聚和滞后制度的状态。最近的工作表明，粗粒度的晶格模型提供了重要的见解滞后和PI寻求建立在这几个方面。在拟议的工作中，PI将扩大可以通过这种方法处理的材料的范围，包括各种中孔二氧化硅材料的应用，并将该方法应用于分析压汞法中的侵入/挤出滞后。第二个研究领域是有关吸附和解吸的动力学。PI的目标是使用模拟动态摄取实验来研究滞后区域中状态的稳定性。PI已经使用这种方法来建立Monte Carlo模拟中遇到的滞后回线的意义，并研究孔阻塞在滞后中的作用。所提出的工作涉及粗粒度晶格模型的动态模拟以及汞孔隙率法的应用。PI还计划将这些技术扩展到纳米技术应用背景下的受限几何形状中的润湿动力学研究。更广泛的影响：该研究虽然是基础，但与应用密切相关，特别是在多孔材料表征方面。传统上，工程师和其他使用多孔材料的人不得不使用相当不精确的量如孔体积、表面积和孔径分布来观察多孔材料的微观结构。预计该项目可以为多孔材料表征的新方法提供基础。从传统的催化和分离领域到新兴的纳米技术领域，多孔材料的应用具有巨大的潜在影响。研究计划通过研究生，博士后学者和本科生的参与具有很强的教育成分。学生们定期参加并在主要会议上介绍他们的工作。研究小组会议的部分目的是培养学生交流他们的研究成果的能力，我们的研究生参加本科课程教学作为他们的学位课程的教育要求。该项目的特点是与工业界（Quantachrome公司）合作，以及与德国柏林技术大学研究人员的国际合作。

Peter A. Monson, University of Massachusetts - Amherst"Modeling Adsorption in Complex Porous Structures: Equilibrium, Hysteresis and Dynamics"This research will use molecular modeling to understand the behavior of fluids confined in porous materials with complex pore structures. The primary goal is to develop a more refined understanding of how the combined effects of molecular interactions and the structure of the porous material over several length scales yield particular kinds of adsorption behavior. This understanding is central to important applications such as separations and catalysis, as well as in porous materials characterization. A combination of dynamical as well as equilibrium modeling techniques is a central feature of this project. Two complementary areas of research are planned.In the first area the PI is concerned with coarse-grained lattice models of adsorption/desorption in complex pore structures. The goal of this work is to develop a framework for understanding the relationship between adsorption measurements and the porous material microstructure - particularly for states in the capillary condensation and hysteresis regime. The recent work has shown that coarse-grained lattice models provide important insights into hysteresis and the PI seeks to build on this in several ways. In the proposed work the PI will extend the range of materials that can be treated by this approach, including applications to a variety of mesoporous silica materials, and apply the approach to analysis of intrusion/extrusion hysteresis in mercury porosimetry.The second research area is concerned with the dynamics of adsorption and desorption. The PI's goal here is to use simulations that mimic dynamic uptake experiments to investigate the stability of states in the hysteresis region. The PI has used this approach to establish the significance of the hysteresis loops encountered in Monte Carlo simulations and to investigate the role of pore blocking in hysteresis. The proposed work deals with dynamical simulations of coarse-grained lattice models as well as application to mercury porosimetry. The PI also plans to extend these techniques to the study of wetting dynamics in confined geometries in the context of nanotechnology applications.Broader Impact: The research while fundamental is closely linked with application, especially in the context of porous materials characterization. Traditionally engineers and others using porous materials have had to view the porous material microstructure using rather imprecise quantities like the pore volume, surface area and pore size distribution. It is anticipated that the project could provide a foundation for a new approaches to the characterization of porous materials. There is substantial potential impact in applications of porous materials ranging from traditional areas such as catalysis and separations to emerging areas in nanotechnology.The research program has a strong educational component through the involvement of graduate students, postdoctoral scholars and undergraduates. The students regularly attend and present their work at major conferences. Research group meetings are designed in part to develop the ability of students to communicate their research achievements, and our graduate students participate in teaching undergraduate courses as an educational requirement of their degree program. The project features collaboration with industry (Quantachrome Corporation) as well as an international collaboration with researchers at the Technical University of Berlin, Germany.