Metal–organic framework adsorbents for selective divalent cation removal/recovery from water

Elevated levels of divalent metal ions in water pose significant risks to human health and the environment. Among various water treatment technologies, adsorption stands out for its high efficiency, simplicity, and versatility. Metal-organic frameworks (MOFs), a class of highly tunable porous materials, have emerged as promising candidates for the selective removal and recovery of valuable divalent cations from aqueous systems. This review provides a comprehensive overview of recent advances in MOF design and functionalization strategies that enhance selective adsorption performance, particularly in the presence of competing ions. We highlight key adsorption mechanisms, address current challenges, and discuss future directions for the application of MOFs in water purification and resource recovery.