An anionic metal-organic framework as a platform for charge-and size-dependent selective removal of cationic dyes

A novel anionic framework [Me2ND2](0.5)[In0.5L0.5]center dot xDMF}(n) (1) with two one-dimensional (1D) channels along the b axis of about 7.37 x 11.95 angstrom and 6.58 x 7.24 angstrom was solvothermally synthesized and characterized. The adsorption studies on organic dyes having different charges and sizes indicate that compound 1 exhibits selective adsorption and separation behavior for cationic dyes through an ion-exchange process due to the presence of an intrinsic anionic framework. Additionally, compound 1 can selectively separate methylene blue (MB+) from the cationic dyes mixture consisting of methylene blue (MB+) and rhodamine B (RhB+). Moreover, when implemented as chromatographic column stationary phases, compound 1 displays efficient and selective separation of MB+ from both anionic-cationic dyes mixture and only cationic dyes mixture.