Selective binding of Pb2+ with manganese-terephthalic acid MOF/SWCNTs: Theoretical modeling, experimental study and electroanalytical application

A nanocomposite of flake-shaped manganese-terephthalic acid MOF/single-walled carbon nanotubes (Mn(TPA)-SWCNTs) was synthesized using manganese chloride, terephthalic acid and SWCNTs as raw materials. Theoretical modeling study shows that the Mn(TPA) component has stronger adsorption ability to lead ion (Pb2+) than the other common heavy metal ions, which is in good agreement with the result of electrochemical assay. Then, the Mn(TPA)-SWCNTs were used as a sensing matrix for the voltammetric determination of Pb2+. The results displayed that the sensor shows high analytical performance for Pb2+ due to the synergy of Mn(TPA) with highly selective binding to Pb2+ and SWCNTs with high electronic conductivity. Under the optimal conditions, the Mn(TPA)-SWCNTs-based electrochemical sensor presented a wide linear response over the concentration range from 0.10 to 14.0 μM. The limit of detection was achieved to be 38 nM. Satisfactory results were also achieved when the Mn(TPA)-SWCNTs-based sensor was utilized for the determination of Pb2+ in the practical samples of industrial wastewater and human serum, suggesting great promising of the sensor for practical application.