Computational screening of hydrophobic zeolites for the removal of emerging organic contaminants from water

Abstract

The pollution of water resources by pharmaceuticals and agents of personal care products (PPCPs) poses an increasingly pressing issue that has received considerable attention from scientists and government agencies alike. Hydrophobic zeolites can serve as selective adsorbents to remove these contaminants from aqueous solution. So far, the adsorption of PPCPs in zeolites has often been investigated in case studies focusing on a small number of contaminants and one or a few zeolites. We present a computational screening approach to investigate the interaction of 53 PPCPs with 14 all-silica zeolites, aiming at a more comprehensive understanding of factors that are beneficial for a strong host-guest interaction and thus an efficient adsorption. The systems are modelled on the classical force field level of theory, allowing for the efficient computational treatment of a large number of PPCP-zeolite combinations and evaluated in terms of the interaction energy between PPCP and zeolite framework. For selected PPCP-zeolite combinations additional Free Energy Perturbation simulations are employed to compute Free Energies of Transfer between the aqueous phase and the adsorbed state. These results can serve as a starting point for experimental studies of relevant PPCP-zeolite combination or more in-depth theoretical investigations. Furthermore, the calculations can provide guidelines for the design of zeolite composite materials or even new zeolite frameworks with enhanced adsorption properties.

Adsorption of the anticancer drug 5-fluorouracil in faujasite-type zeolites studied with density functional theory calculations

“…It is clear that the use of idealised models of perfect zeolite crystals constitutes a certain limitation, as not all features that may play a role in real materials (defects, intrinsic mesoporosity, …) are incorporated in the modelling. So far, atomistic modelling methods have been employed to study the adsorption of pharmaceuticals in zeolites, both in the context of "screening" studies addressing a range of compounds in different zeolites with computationally efficient force field (FF) methods 54,55 and in studies of individual compounds using computationally more expensive density functional theory (DFT) calculations. 33,[56][57][58][59] The specific topic of 5-FU adsorption in zeolites has so far received limited attention from the computational perspective, the previously mentioned study of 5-FU diffusion by Spanakis et al being an exception.…”

Adsorption of 5-fluorouracil, an anticancer drug, in faujasite-type zeolites: Understanding storage and release with density functional theory calculations

“…It is clear that the use of idealised models of perfect zeolite crystals constitutes a certain limitation, as not all features that may play a role in real materials (defects, intrinsic mesoporosity, …) are incorporated in the modelling. So far, atomistic modelling methods have been employed to study the adsorption of pharmaceuticals in zeolites, both in the context of "screening" studies addressing a range of compounds in different zeolites with computationally efficient force field (FF) methods 58,59 and in studies of individual compounds using computationally more expensive density functional theory (DFT) calculations. 37,[60][61][62][63] The specific topic of 5-FU adsorption in zeolites has so far received limited attention from the computational perspective, the previously mentioned study of 5-FU diffusion by Spanakis et al being an exception.…”