Structure-Property Relationships in Zeolite Adsorption of G-Series Nerve Agents

This work presents a comprehensive computational study of the adsorption behavior of G‑series organophosphorus compounds (Tabun, Sarin, Soman, Cyclosarin) in representative zeolite frameworks (MFI, MEL, BEA, AFI, FAUs) under both gas and aqueous phases. Adsorption energies, isosteric heats, deformation energies, and differential adsorption parameters were evaluated to elucidate the interplay of molecular polarity, steric constraints, and framework topology. The results reveal that medium‑pore silicalites (MFI, MEL) exhibit classical Type I isotherms and strong selectivity for compact polar guests, while large‑pore BEA and FAU frameworks accommodate bulky agents with extended Type I(b)/Sips profiles and superior capacities. AFI channels enforce strict shape selectivity but are capacity‑limited. Comparison with reported experimental data for non‑toxic simulants (DMMP, TMP) confirms that computed energetics fall within realistic ranges, validating the predictive reliability of the simulations. Complementing the adsorption energetics, combined molecular dynamics analyses (MSD) and radial distribution functions (RDF) reveal how intracrystalline transport and local ordering modulate practical uptake: a short range framework anchoring peak (∼0.95 Å) governs residence time at adsorption sites, while a mid-range clustering peak (∼1.6 Å) reflects intermolecular assemblies whose transport consequence is topology dependent (mobile clusters in open FAU/BEA vs. immobilizing aggregates in 1D/non intersecting channels such as MEL/AFI). Overall, this study highlights the dual role of polarity and steric fit in governing adsorption selectivity and emphasizes the importance of tuning framework topology and Si/Al ratio to balance guest uptake and water competition, providing a rational basis for the design of porous adsorbents for hazardous organophosphorus compounds.