Research in fluid-solid interaction processes has expanded tremendously over the past few decades, with key fronts ranging from fundamental understanding of reaction kinetics to detailed predictions involving the release, migration, and retention of environmentally important components. This special issue of AJS showcases the diversity and progress of this research in a series of invited papers that also illustrate core problems and solutions. A central theme is the challenge involved in the integration of reaction processes over length and time scales that span many orders of magnitude. At one end of this spectrum, both theoretical and modeling approaches have evolved to describe the very brief interactions at the molecular scale, allowing key insights into details of reaction mechanism. At the other, modeling approaches have focused on the longer reaction times and lengths that characterize macroscopic to mesoscale systems. Experimental and analytical observations are also now able to map the dynamics and reactivity of reacting surfaces at the pore scale and above, providing these modeling approaches with essential feedbacks towards validation of predictions and identification of aspects where improvement is needed. The strong coupling between the two “worlds” of experimental and simulation approaches is perhaps the most important result of the last years of research in our field, and a primary motivation for this special issue was to highlight this productive interaction. A second motivation was to mark the 60th birthday of Professor Andreas Lüttge. Starting his scientific work at Tübingen University, followed by appointments at Yale University, Rice University, and now at the University of Bremen, he has continued to pursue the productive synergy of these two activities via pioneering work combining kinetic Monte Carlo simulations with complementary observations of reacting mineral surfaces. This special issue is published in two parts. This first part begins with theoretical work by Bender and Becker, involving the kinetics of interactions between redoxsensitive plutonyl species, iron, and hydroxyl radical. This work nicely illustrates a divide-and-conquer approach, elucidating the stepwise reaction sequence involved in the formation and configuration of various complexes. In so doing, it also provides a potential framework for approaching related problems in the context of interactions at mineral surfaces. The second contribution, by Churakov and Prasianakis, combines thermodynamic calculations and kinetic simulations. Here the authors use the scale of the pore itself as a central connector to elegantly link the atomistic description of mineral surface reactivity with structural and compositional heterogeneities of real materials. The third contribution, by Kim, Marcano, Ellis, and Becker, presents experimental data on the photocatalytic role of TiO2 nanoparticles in uranyl reduction, using a diverse array of organic ligands as electron donors. This study demonstrates the importance of understanding the environmental specificity of reactions at surfaces, documenting the sensitivity of reduction efficiency to both ligand availability and UV wavelength. The last paper in this special issue’s first part, by Gebauer, Raiteri, Gale, and Cölfen, provides insight into current discussions concerning the birth of crystal nuclei during homogeneous precipitation in solution. They provide a nice summary of the ongoing debate, and stimulate further examination of true nature of these processes, arguing that the “critical” aspect of these clusters lies not in their size, but in their dynamics. This last point also bears on a larger, fundamental problem: how to resolve our new and increasing knowledge of the kinetics of these microscopic interactions with the conventional thermodynamic framework that has long guided our interpretations [American Journal of Science, Vol. 318, November, 2018, P. iii–iv, DOI 10.2475/09.2018.01]

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前言

在过去的几十年里，流固相互作用过程的研究得到了极大的扩展，关键前沿从对反应动力学的基本理解到涉及环境重要成分的释放、迁移和保留的详细预测。本期 AJS 特刊在一系列特邀论文中展示了这项研究的多样性和进展，同时阐述了核心问题和解决方案。一个中心主题是在跨越多个数量级的长度和时间尺度上整合反应过程所涉及的挑战。在这一范围的一端，理论和建模方法都已经发展到在分子尺度上描述非常简短的相互作用，从而可以深入了解反应机制的细节。另一方面，建模方法侧重于表征宏观到中尺度系统的较长反应时间和长度。实验和分析观察现在也能够在孔隙尺度及以上绘制反应表面的动力学和反应性，为这些建模方法提供必要的反馈，以验证预测和识别需要改进的方面。实验和模拟方法的两个“世界”之间的强耦合可能是我们领域最近几年研究的最重要结果，而本期特刊的主要动机是强调这种富有成效的互动。第二个动机是纪念 Andreas Lüttge 教授 60 岁生日。在图宾根大学开始他的科学工作，随后在耶鲁大学、莱斯大学和现在的不来梅大学任职，他通过将动力学蒙特卡罗模拟与反应矿物表面的互补观察相结合的开创性工作，继续追求这两项活动的富有成效的协同作用。本期特刊分两期出版。第一部分从 Bender 和 Becker 的理论工作开始，涉及氧化还原敏感的钚基物种、铁和羟基自由基之间相互作用的动力学。这项工作很好地说明了分而治之的方法，阐明了各种配合物的形成和配置所涉及的逐步反应序列。这样做，它还提供了一个潜在的框架，用于在矿物表面相互作用的背景下处理相关问题。第二个贡献，由 Churakov 和 Prasianakis 编写，结合了热力学计算和动力学模拟。在这里，作者使用孔隙本身的尺度作为中心连接器，将矿物表面反应性的原子描述与真实材料的结构和成分异质性巧妙地联系起来。Kim、Marcano、Ellis 和 Becker 的第三项贡献提供了关于 TiO2 纳米粒子在铀酰还原中的光催化作用的实验数据，使用各种有机配体作为电子供体。这项研究证明了了解表面反应的环境特异性的重要性，记录了还原效率对配体可用性和紫外线波长的敏感性。本期特刊第一部分的最后一篇论文，作者是 Gebauer、Raiteri、Gale 和 Cölfen，深入了解当前关于溶液中均相沉淀过程中晶核诞生的讨论。它们对正在进行的辩论进行了很好的总结，并激发了对这些过程的真实性质的进一步检查，认为这些集群的“关键”方面不在于它们的大小，而在于它们的动态。最后一点也涉及一个更大的基本问题：如何解决我们对这些微观相互作用动力学的新知识和日益增长的知识，以及长期以来一直指导我们解释的传统热力学框架[美国科学杂志，卷。318，2018 年 11 月，第 iii-iv 页，DOI 10.2475/09.2018.01] 并激发对这些过程的真实性质的进一步研究，认为这些集群的“关键”方面不在于它们的大小，而在于它们的动态。最后一点也涉及一个更大的基本问题：如何解决我们对这些微观相互作用动力学的新知识和日益增长的知识，以及长期以来一直指导我们解释的传统热力学框架[美国科学杂志，卷。318，2018 年 11 月，第 iii-iv 页，DOI 10.2475/09.2018.01] 并激发对这些过程的真实性质的进一步研究，认为这些集群的“关键”方面不在于它们的大小，而在于它们的动态。最后一点也涉及一个更大的基本问题：如何解决我们对这些微观相互作用动力学的新知识和日益增长的知识，以及长期以来一直指导我们解释的传统热力学框架[美国科学杂志，卷。318，2018 年 11 月，第 iii-iv 页，DOI 10.2475/09.2018.01] 如何解决我们对这些微观相互作用动力学的新知识和日益增长的知识，以及长期以来一直指导我们解释的传统热力学框架[美国科学杂志，卷。318，2018 年 11 月，第 iii-iv 页，DOI 10.2475/09.2018.01] 如何解决我们对这些微观相互作用动力学的新知识和日益增长的知识，以及长期以来一直指导我们解释的传统热力学框架[美国科学杂志，卷。318，2018 年 11 月，第 iii-iv 页，DOI 10.2475/09.2018.01]