Design of two isoreticular Cd-biphenyltetracarboxylate frameworks for dye adsorption, separation and photocatalytic degradation.

Two novel isoreticular cadmium metal-organic frameworks (MOFs) with the framework formula of [Cd2 (BPTC)(solvent)3 ] (H4 BPTC = 3,3',5,5'-biphenyltetracarboxylic acid) have been constructed under diverse reaction conditions and characterized by single crystal X-ray diffraction, PXRD, IR and TGA. The neutral 3D frameworks of 1 and 2 with one-dimensional (1D) rhombic channels exhibit both distinct uptake and good selectivity for cationic methylene blue (MB) dye molecules. The adsorption capacity and adsorption kinetic constant of 2 are greater than those of 1, showing the importance of porosity and pore size during the adsorption. Moreover, both MOFs show effective degradation of rhodamine B (RhB) and methyl orange (MO) dyes under UV light irradiation.