Highly Water-Stable Zn₅ Cluster-Based Metal-Organic Framework for Efficient Gas Storage and Organic Dye Adsorption

The development of multi-functional materials as physical adsorbents for gas storage and dye adsorption is of utmost importance for ecological environment management. Ionic metal-organic frameworks (MOFs) with exchangeable counterions would easily be modified to enhance their performance. Herein, we report a novel {Zn₅}-based MOF (SDU-CP-2) with the dimethylamine cation [(CH₃)₂NH₂]⁺ in its crystal structure, which can be readily exchanged with Li⁺ ions and cationic dyes. Consequently, it exhibits high CO₂ and C₂H₂ adsorption capacities as well as charge/size-selective adsorption of dye molecules. The adsorption of SDU-CP-2 toward cationic dyes was confirmed to be efficient in terms of recyclability and ion-exchange mechanisms. The column filler experiment and high water stability decisively supported its potential application in waste water treatment.