An electrochemical sensor constructed by intercalated composites was developed for determination of heavy metal ions. The intercalated composites were composed of hydrosulphonyl functional covalent organic frameworks (COF-SH) and graphene (G). The presence of numerous adsorption sites, such as 18 sulfur atoms and 30 nitrogen atoms per big circle of COFs on COF-SH, was beneficial for the accumulation of heavy metals, while the graphene enhanced the electrical conductivity. The obtained sensor under the optimal conditions successfully detected the presence of heavy metal ions in coastal water samples at concentrations ranging from 1 to 1000 μg L-1. The detection limits of Cd (II), Pb (II), Cu (II), and Hg (II) were 0.3, 0.2, 0.2, and 1.1 μg L-1, respectively. Furthermore, the sensor still exhibited good stability after multiple uses less than 5%. When it is used in the analysis of actual samples, the recovery of standard addition is higher than 95%. In sum, the combination of hydrosulphonyl functional COFs with graphene looks very promising for the assembly of sensors with high sensitivity toward the determination of heavy metal ions for coastal environmental monitoring.
Keywords: Covalent organic frameworks; Electrochemical sensors; Graphene; Heavy metal; Nanocomposite; Sea water analysis.
© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.