Effective removal of cobalt from aqueous solution by Mn-MOF-74 synthesized using room-temperature, water-based synthesis method

A novel adsorbent, Mn-MOF-74, was synthesized using a room-temperature, water-based method by assembling Mn 2+ metal nodes with 2,5-dihydroxyterephthalic acid ligands, and was further applied for Co 2+ removal. Mn-MOF-74 exhibited minimal pH dependence within a pH range of 3–8.5, achieving Co 2+ removal efficiencies between 92.5 and 96.3%, with a distribution coefficient of up to 2.9 × 10 4  mL·g −1 . A function relationship between the Co 2+ removal efficiency and the adsorbent dosage or initial concentration was proposed. The dominant removal mechanism was identified as ion exchange between Mn 2+ and Co 2+ , with chemisorption being the primary rate-limiting step.