Highly sensitive detection of lead ions and cadmium ions based on UiO-66-NH2@carbon nanohorns composites enhanced by bismuth film in water environment

Heavy metal ions are common industrial pollutants widely existing in the ecosystem, which can damage the environment and threaten human health. It is necessary to develop an accurate detection technology for the quantification of heavy metal ions in water environment. In this work, the electrochemical sensor based on bismuth/UiO-66-NH 2 @carbon nanohorns (Bi/UiO-66-NH 2 @CNHs) was developed for the simultaneous detection of lead ions (Pb 2+ ) and cadmium ions (Cd 2+ ). The results showed that the synergies of Bi/UiO-66-NH 2 @CNHs provided larger electrochemical active surface area and higher electron transfer ability than those of single materials. Furthermore, the high binding ability of bismuth film with heavy metal ions enhanced the enrichment of Pb 2+ and Cd 2+ during the electrochemical detection, thus further improving the response current. Based on this, the fabricated sensor displayed good linear relationships of 0.20 μM ~ 0.80 μM of Pb 2+ and Cd 2+ , with lower detection limits of 6.65 nM (Pb 2+ ) and 10.56 nM (Cd 2+ ). In the actual samples testing, the recovery rates of Pb 2+ and Cd 2+ were 97.10% ~ 98.76% and 97.51% ~ 103.32%, respectively, and the relative standard deviations of Pb 2+ and Cd 2+ were less than 4.10% and 4.02%, respectively. Moreover, there was no statistical significance difference between the developed sensor and the certified method. This work provides a new idea for the quantification of heavy metal ions in water environment. • The synergies of Bi, UiO-66-NH 2 , and CNHs increase the electron transfer rate • Bismuth further improves the ability to enrich heavy metal ions • The method can detect Pb 2+ and Cd 2+ simultaneously • The method proposed in this work has a low detection limit