GaOOH-modified metal-organic frameworks UiO-66-NH2: Selective and sensitive sensing four heavy-metal ions in real wastewater by electrochemical method.

Heavy metal pollution in the environment poses a serious threat to the ecosystem and human health, which has attracted widespread attention. In this study, an octahedral structure composite composed of UiO-66-NH2 MOFs and semiconductor GaOOH materials has been prepared and used as electrode materials successfully. These composites can be used for the real-time and online determination of Cd2+, Cu2+, Hg2+, and Pb2+ in real water samples simultaneously or alone via an electrochemical method. Zr-MOF has a large and unique surface area that is beneficial to the adsorption and preconcentration of heavy metal ions. The experiment parameters such as pH, deposition potential, and deposition time were optimized. Under the optimized conditions, the electrochemical performances and practical applications of Zr-MOF composites modified electrode have been investigated, which shows excellent wider linear range and lower detection limit (LOD). The results demonstrated excellent selectivity, reproducibility, stability and applicability for the detection of four metal ions. These superior features stem from the synergistic reaction mechanism of UiO-66-NH2 and GaOOH. In addition, it has been established a new detection strategy for heavy metal ions through the form of metal-organic framework (MOF) composite in this work. It may provide a novel platform for the quantitative determination of heavy metal ions in various environmental samples.