Scalable Aqueous Synthesis of a Biological Robust Metal-Organic Framework for Ethanol-Water Separation

Ultradry ethanol is widely and crucially used in industry, primarily owing to its excellent solvent properties, reactivity, relatively low toxicity, and volatility. However, trace amounts of water present within it can significantly diminish its efficacy. Herein, we designed a low-cost and green-synthesized metal-organic framework material (ZNU-68) for kinetic ethanol/water separation. Owing to its larger kinetic diameter compared to water, ethanol diffuses more slowly within the pores, consequently leading to differences in both the adsorption capacity and adsorption rate. Ten cycles of dynamic vapor adsorption tests for water confirm that ZNU-68 possesses excellent stability and regenerability. Under a feed composition of ethanol/water = 95/5, a high productivity of anhydrous ethanol (18.36 mol/kg) is achieved. Density functional theory calculations and water-loaded single-crystal structures indicate that ZNU-68 has two distinct adsorption sites for water molecules.