• Zeolite topology controls selectivity between compact and bulky organophosphorus guests. • Si/Al ratio tunes the trade-off between adsorption strength and water tolerance. • Simulated adsorption energies and capacities align closely with experimental ranges. • Modeling provides a predictive roadmap for tailoring zeolites to capture toxic agents. The adsorption of organophosphorus compounds (OPCs) in zeolites was systematically investigated through a multi-framework computational study that integrates molecular descriptors with host structural parameters. Four representative guests-trimethylphosphine oxide (TMPO), dimethylmethoxy phosphine (DMMPO), dimethyl methylphosphonate (DMMP), and trimethyl phosphonate (TMP)-were examined across seven zeolite frameworks (MFI, MEL, BEA, AFI, and FAU with variable Si/Al ratios). Gas- - and liquid-phase simulations revealed pronounced phase-dependent variations in molecular volume and polarity, with TMP exhibiting the largest solvent-accessible surface area. Adsorption energetics-including adsorption energy (Eads), deformation energy (E def ), differential adsorption energy (dE ads /dNi), and isosteric heat (Qst)-were employed to evaluate binding strength, site heterogeneity, and water competition. Framework-specific analyses demonstrated that medium-pore zeolites (MFI, MEL) favor compact polar sorbates but penalize bulky guests, BEA accommodates both compact and bulky molecules with high loadings, AFI’s one-dimensional channels selectively stabilize elongated species, and FAU’s supercages eliminate steric penalties while the Si/Al ratio tunes polarity and hydrophilicity. Integrated performance mapping identified DMMP as the most consistent sorbate across frameworks, DMMPO as the most balanced in aqueous systems, TMP as highly framework-dependent, and TMPO as strongly adsorbed but water-sensitive. Modeled adsorption capacities (≈25–110 mg·g⁻¹) aligned with experimental ranges (30–200 mg·g⁻¹), validating the predictive framework. Molecular dynamics simulations combined with mean square displacement (MSD) and radial distribution function (RDF) analyses elucidate how zeolite topology controls the diffusion of organophosphorus compounds. Across MFI, MEL, BEA, FAU, and AFI frameworks, simulated diffusivities consistently fall within the experimental window of 10⁻⁶-10⁻⁵ cm²/s and reproduce framework‑dependent inversions in mobility order. RDF profiles reveal that polarity‑driven short‑range anchoring and mid‑range clustering dictate whether confinement suppresses or enhances transport, explaining why TMP is fast in MFI but the slowest in MEL, while DMMP shifts from the slowest in MFI to the quickest in BEA and FAU. The close agreement between simulated and experimental diffusion coefficients for DMMP, TMP, and related compounds validates the predictive power of this computational approach. These findings provide a unified mechanistic understanding of organophosphorus mobility in zeolites and offer guidance for the rational design of porous materials for selective adsorption and separation.
Gorgichi et al. (2026) studied this question.