Construction of heterogeneously connected cobalt-based MOF-COF and its application in highly selective separation of trace lead ions

• Published in: Talanta (Oxford) 2024-10, Vol.278, p.126546, Article 126546
• Main Authors: Li, Wei-Tao, Zhang, Shuo, Guo, Huanhuan, Yu, Ling, Xing, Cuijuan
• Format: Article
• Language: English
• Subjects: Covalent organic framework; Metal organic framework; Pb2+ ions; Separation; Solid phase extraction
• ISSN: 0039-9140; 1873-3573; 1873-3573
• DOI: 10.1016/j.talanta.2024.126546

As a new type of porous crystalline composite material, MOF-COF has shown great advantages in metal separation. Herein, a CoMOF-COF was designed for highly selective separation of trace Pb2+ ions. The designed CoMOF-COF has a high density of nitrogen-oxygen functional groups and can selectively separate metal ions. There is a strong affinity between the designed CoMOF-COF material and metal Pb2+ ions, which can be attributed to the ordered heterogeneous porous structure and large amounts of nitrogen-and oxygen-containing functional groups. The composite showed high adsorption selectivity for Pb2+ ions and had adsorption capacity of 33 mg g−1, with high chemical stability. Based on this solid phase extraction material, a high sensitivity detection method for Pb2+ ions was established, which has the detection limit of 37.3 ng L−1, precision of 1.9 %. Linear detection range is 0.2–10 ng mL−1, and the detection of Pb2+ ions in actual water samples was realized. Through this study, it is proved that the strong affinity between the designed CoMOF-COF materials and metal Pb2+ ions can be attributed to the soft and hard acid-base theory, which reveals the structure-activity relationship between the porous heterostructure of such materials and metal separation, providing a highly selective separation material for the separation of other environmental pollutants. For TOC Only. [Display omitted] •A heterogeneously connected CoMOF-COF was designed for highly selective separation of lead ions.•Compared with individual COF and MOF materials, CoMOF-COF exhibits synergistic enhancement of lead ions enrichment.•The lead ions detection system exhibits high sensitivity and strong anti-interference ability.•SPE method based on CoMOF-COF was applied for the analysis of lead ions in environmental water samples.