A Design Concept Towards Water-Stable Cu-Based MOFs for Efficient Nitrate Adsorption

In water purification technologies, long-term stability of metal-organic frameworks (MOFs) in aqueous environments is essential for practical development. This research introduces a novel synthesis approach using dual ligands to fabricate mixed-coordination Cu-based MOFs: Cu2(Hbtc)2(bpe)2 (TUW-1) and Cu2(Hbtc)2(4,4’-bipy)2(H2O)2] (TUW-2). Both frameworks maintain their structural integrity for at least 365 days under various conditions. Additionally, they exhibit remarkable nitrate adsorption capacity of 119.42 mg g-1 and 105.93 mg g-1 for TUW-1 and TUW-2 respectively and selectivity due to free carboxylic acid groups, even under neutral pH conditions and in the presence of competing ions. The exceptional adsorption performance and stability of these MOFs make them highly promising for a wide range of applications in aqueous media.