2024 AIChE Annual Meeting
(155a) Thermodynamics and Molecular Modeling of Adsorption Induced Deformation
Authors
Neimark, A. - Presenter, Rutgers University
Parashar, S., Rutgers, The State University of New Jersey
Corrente, N., Rutgers University
Guest molecules adsorbed in pores of a solid body exert substantial stress on the host matrix that causes its swelling or contraction depending on the nature of host-guest interactions. Various manifestations of adsorption induced deformation are currently actively explored with respect to the design of novel nanoporous adsorbents and membranes for hydrocarbon separation, actuators, nanobumpers, energy storage devices, as well as the enhancement ofgas recovery from shales and carbon dioxide sequestration in coal mines. Despite of the evident importance of the deformation effects during adsorption-desorption cycles, a rigorous theoretical description of this phenomenon validated against the experiments is lacking. A similar problem arises in case of intrusion-extrusion of nonwetting fluids, the process involving high applied pressures. A general thermodynamic approach is developed to predicting adsorption stress and respective deformation in nanoporous materials of different origin based on molecular models of fluid sorption within elastic nanoscale confinements.The theoretical modeling is complemented by direct molecular simulation of adsorption-induced deformation using the iterative hybrid MD-MC method. A special attention will be paid to the peculiar counterintuitive effects of non-monotonic deformation of a porous body upon fluid saturation with consequent stages of contraction and expansion. Examples of quantitative comparison of the theoretical predictions with experiments include metal-organic frameworks (MOFs), microporous carbons and zeolites, mesoporous crystals, coal, and hierarchical micro-mesoporous monoliths.