Synthesis of two novel H₄TCPBDA-based metal–organic frameworks and their application in lead ion adsorption

Two novel porous metal–organic frameworks (MOFs) Cu(TCPBDA) and Cd(TCPBDA) based on a new ligand, namely N,N,N′,N′-tetrakis(4-carboxyphenyl)biphenyl-4,4′-diamine (H₄TCPBDA), were synthesized by solvent thermal method and characterized with scanning electron microscopy, powder X-ray diffraction, BET analysis and spectrofluorometry. The static adsorption of the two MOFs for lead ions (Pb²⁺) was investigated. Cu(TCPBDA) showed a higher adsorption capacity for Pb²⁺ compared with Cd(TCPBDA), and its maximum adsorption capacity was 300 mg/g. The adsorption performance of Cu(TCPBDA) was then further studied. It was found that the adsorption of Cu(TCPBDA) for Pb²⁺ fitted the Freundlich model and pseudo-second-order equation very well. The adsorption ability of Cu(TCPBDA) was applied to fast and efficient adsorption for Pb²⁺ in toner. The results indicates that Cu(TCPBDA) is a promising material in adsorption and removal of heavy metal ions.