Mass-transfer of binary mixtures in DDR single crystals

For the first time, micro imaging by interference microscopy (IFM) is applied for studying uptake and release of guest molecules in nanoporous host material for investigating the adsorption of gas mixtures and for correlating the thus observed behavior with corresponding single-component sorption experiments. Combining the advantages of high spatial and temporal resolution in the order of 0.45 μm and 15 s, respectively, this promising approach results in time-dependent two-dimensional profiles of the intra-crystalline sorbate concentration of the single crystal under study [1, 2, 3]. However, with the lack of differentiation of different species present inside the microporous framework only certain types of experiments seems feasible, notably when the mixture consists of species with large differences in the rate of mass transport under the confinement of the channels, cages and windows of e.g. zeolite ZSM-58, which is well known from previous IFM studies [4].