An anionic cadmium-organic framework with an uncommon 3,3,4,8-c network for efficient organic dye separation

• Published in: Polyhedron 2020-09, Vol.188, p.114685, Article 114685
• Main Authors: Liu, Xiuping, Hao, Chunlian, Cui, Liang, Wang, Yijun
• Format: Article
• Language: English
• Subjects: 3,3,4,8-c Network; Adsorption; Metal-organic frameworks; Organic dyes; Separation; Uncoordinated carboxylate groups
• ISSN: 0277-5387
• DOI: 10.1016/j.poly.2020.114685

A novel anionic cadmium–organic framework has been solvothermally synthesized and characterized. LYU-2 contains microporous channels with a complicated 3D tetranodal 3,3,4,8-c network and uncoordinated carboxylate groups, exhibiting excellent selective adsorption and separation of small cationic dyes in aqueous solution. Furthermore, the adsorbed MB+ can be gradually released. [Display omitted] •A novel anionic metal–organic framework (LYU-2) was synthesized.•LYU-2 contains microporous channels with a complicated 3D tetranodal 3,3,4,8-c network and uncoordinated –COO− groups.•LYU-2 shows excellent selective adsorption and separation of small cationic dyes in aqueous solution.•The adsorbed MB+ can be gradually released in a NaCl-containing aqueous solution. A novel anionic metal–organic framework (MOF), {[Cd5(L)4·Na2·(H2O)]·2(CH3)2NH2·3DMF} (LYU-2, Linyi University) (H5L = 2,5-bis(3′,5′-dicarboylphenyl)-benzoic acid), has been solvothermally synthesized and characterized. LYU-2 contains microporous channels with a complicated 3D tetranodal 3,3,4,8-c network, uncoordinated carboxylate groups and coordinated H2O molecules, exhibiting excellent selective adsorption and separation of small cationic dyes through an ion-exchange process in aqueous solution. According to UV/Vis spectroscopy analysis of LYU-2, methylene blue (MB+) and crystal violet (CV+) can be rapidly adsorbed, whereas larger rhodamine B (RB+), anionic methyl orange (MO−), and neutral sudan II (SD0) can hardly be adsorbed. The results imply that the adsorption of dye molecules in LYU-2 displays not only a charge effect, but also a size- and shape-exclusive effect. Furthermore, the adsorbed MB+ can be gradually released in a NaCl-containing aqueous solution.