Adsorption of pharmaceuticals and related compounds in cation-exchanged zeolites – A computational perspective

沸石是多孔无机骨架材料，由于晶体结构中存在通道或空腔而具有固有孔隙率。在铝硅酸盐沸石中，负骨架电荷通过带正电的物质（主要是质子或金属阳离子）平衡。阳离子交换已被确立为改变沸石材料的应用相关性质的通用技术。除了已建立的应用程序（例如，沸石还可以用于吸附药物和相关的功能性有机分子，目标应用是废水处理（去除“新兴污染物”）或药物输送。然而，到目前为止，只有少数实验研究研究了这些用途的阳离子交换沸石，并且很大程度上缺乏对阳离子类型对功能有机分子吸附的影响的系统见解。在这个项目中，原子模拟的分散校正密度泛函理论（DFT）的框架将被用来研究药物和相关化合物与沸石吸附剂含有不同的阳离子的相互作用。重点将放在两个大孔沸石的特别相关的应用程序（FAU和莫尔框架类型），考虑系统含有阳离子从不同的群体。该项目的第一部分将包括在优选阳离子位点和吸附能方面对DFT方法进行彻底验证。在第二部分中，阳离子沸石和一组“模型化合物”，相对简单的药物含有代表性的功能基团，之间的相互作用将被系统地研究，考虑不同的阳离子物种以及在Si/Al比和框架类型（FAU/莫尔）的变化。第三部分将进行一系列案例研究：在已发表的实验研究的基础上，将确定在废水处理或药物输送方面特别感兴趣的有机物种。DFT计算将研究它们与阳离子沸石的相互作用，不仅比较不同的阳离子类型，而且考虑与实际应用相关的各种其他方面，例如温度的影响和水的竞争吸附。总而言之，在这个项目中进行的计算将导致更好的原子级理解功能有机分子和阳离子沸石之间的相互作用，为定制沸石吸附剂的开发提供有价值的见解。虽然该项目本身是一个纯粹的计算性质，预计它将刺激更多的应用研究活动，允许鉴定沸石-客体组合，保证更全面的实验研究。

Zeolites are porous inorganic framework materials that possess an intrinsic porosity due to the presence of channels or cavities in the crystal structure. In aluminosilicate zeolites, the negative framework charge is balanced through positively charged species, mostly protons or metal cations. Cation exchange has been established as a versatile technique to modify application-relevant properties of zeolite materials. Beyond established applications (e.g., catalysis, gas separation), zeolites could also find use in the adsorption of pharmaceuticals and related functional organic molecules, targeting applications in wastewater treatment (removal of “emerging contaminants”) or in drug delivery. So far, however, only a few experimental studies have studied cation-exchanged zeolites for these uses, and systematic insights into the impact of the cation type on the adsorption of functional organic molecules are largely lacking. In this project, atomistic simulations in the framework of dispersion-corrected density functional theory (DFT) will be used to study the interaction of pharmaceuticals and related compounds with zeolite adsorbents containing different cations. Focus will be on two large-pore zeolites of particular relevance to applications (FAU and MOR framework types), considering systems containing cations from different groups. The first part of the project will comprise a thorough validation of the DFT methodology, both in terms of preferred cation sites and adsorption energies. In the second part, the interaction between cationic zeolites and a set of “model compounds”, relatively simple pharmaceuticals containing representative functional groups, will be studied systematically, considering different cation species as well as variations in Si/Al ratio and framework type (FAU/MOR). A set of case studies will be performed in the third part: On the basis of published experimental studies, organic species of particular interest in the context of wastewater treatment or drug delivery will be identified. DFT calculations will then be employed to study their interaction with cationic zeolites, not only comparing different cation types, but also considering various additional aspect of relevance for real-world applications, such as the impact of temperature and the competitive adsorption of water. Altogether, the calculations performed in this project will lead to a better atomic-level understanding of the interactions between functional organic molecules and cationic zeolites, delivering valuable insights for the development of tailored zeolite adsorbents. While the project itself is of a purely computational nature, it is anticipated that it will stimulate more applied research activities by allowing the identification of zeolite-guest combinations that warrant a more comprehensive experimental investigation.