Diffusion and Adsorption in Porous Solids

Impact of Geometrical Disorder on Phase Equilibria of Fluids and Solids Confined in Mesoporous Materials

“…As some examples, they can be used as storage and release materials for pharmaceutical , or biomaterial immobilization . Nanoporous films grown on the external surfaces of nanoparticles can be used as protective or stabilizing shells. , The large specific surface area inherent to these materials determines their good adsorption potential for the purposeful removal of unwanted molecules from liquids or gases and also proves to be extremely useful in heterogeneous catalysis and sensing. ,− Another large application area is mass separation by either molecular sieving or by exploiting differences in the adsorption and transport properties for molecules to be separated. , Notably, in all aforementioned examples the pore structure defines the function either by introducing steric interactions or by supplying a large specific surface.…”

Surface Processes during Sorption of Aromatic Molecules on Medium Pore Zeolites

“…Separation and catalytic production of aromatic molecules is one of the large groups of applications of zeolites amounting to volumes of 400.000 t per year p -xylene production via separation of xylene isomers by sorption (e.g., UOP−PAREX process) or via direct selective catalytic processes such as the shape selective alkylation of toluene. As catalysis and sorption uses primarily the chemical functionality of sites inside the micropores, the transport of the sorbing/reacting molecules (whose size is similar to that of the pores and cages) into the micropores is a critical issue, , which has been intensely studied using experimental 14-19 and theoretical methods. − Due to the complexity of the problem, either the mass transfer process of the molecules from the gas phase to sites inside the pores under nonequilibrium conditions (transport diffusivity) or the mobility of the molecules inside the pores at equilibrium (self-diffusivity) , is described. These processes differ markedly in nature, but using continuum models, the quantitative rate constants obtained from each type of measurement can be converted …”

The Random Walk of Understanding Diffusion

“…Comprehensive representations are given in the respective monographs, [24][25][26] reviews, 27,28 and handbooks. 29,30 Progress in our understanding of diffusion is intimately associated with the history of the introduction and development of the various measuring techniques and the exploration of the areas of their safe application. Depending on his own experience, his background in science and technology, and the circumstances of his career, any researcher in the field will certainly reflect this development in a very personal way.…”