Efficient gas and alcohols uptake and separation driven by hydrophobic/hydrophilic channels in a porous MOF: experimental and theoretical investigation
Utilizing the self-assembly strategy between the paddle-wheel Cu2(COO)4 cluster and a terephthalic acid ligand modified by a triazolyl group, H2tztp = 2-(1H-1,2,4-triazol-1-yl) terephthalic acid, a porous MOFs, [Cu0.5(tztp)0.5]·0.5DMA (1), has been successfully designed and built. 1 is a three-dimensional self-interpenerated framework with (3,6)-connected rtl topology, and contains hydrophilic and hydrophobic channels decorated by rich uncoordinated triazolyl N atoms and benzene rings from tztp ligands, respectively. The unique porous environment leads to not only high gas adsorption amounts for CO2, C2H6, C2H4 and C2H2 but also good separation ability for C2 hydrocarbons over CH4, CO2 over CH4, and C2H2 over CO2 in the MOF. The specific adsorption sites for CO2 and C2 hydrocarbons were explored by molecular simulation. The breakthrough experiments demonstrated the excellent dynamics separation for CO2 and CH4, C2 hydrocarbons and CH4 as well as C2H2 over CO2. The MOF also reveals excellent adsorption and separation ability for CH3OH over other bulkier alcohol molecules.