Molecular dynamics investigation of the self-diffusion of binary mixture diffusion in the metal-organic framework Zn(tbip) accounting for framework flexibility

The self-diffusion of three equimolar mixtures in the metal-organic framework Zn(tbip) has been investigated by molecular dynamics simulations. The simulations take due account of lattice flexibility. The diffusional characteristics are discussed in relation to molecule properties and lattice geometry. The results show that Zn(tbip) may be a useful material for separating methane/ethane and CO2CO2/ethane mixtures at low concentrations, and CO2CO2/methanol mixtures at high concentrations.

Graphical abstractMD Simulations of diffusion of binary mixtures in Zn(tbip) show that the lattice flexibility must be taken into account if ethane or methanol is involved. It turns out that Zn(tbip) may be a useful material for separating methane/ethane and CO2/ethane mixtures at low concentrations, and CO2/methanol mixtures at high concentrations.Figure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights► MD Simulations of diffusion in a flexible lattice of Zn(tbip) are performed. ► The flexibility leads to an increasing size of the bottleneck for higher loadings. ► The loading dependence and mixture effects for hydrocarbons are examined. ► The influence of the flexibility on diffusion is crucial in some cases.