Ultrasensitive detection and efficient removal of mercury ions based on covalent organic framework spheres with...

In present work, a new spherical covalent organic framework (TFPB-APTU COF) with good photoelectric property and double active sites (secondary amine (-NH-) group and sulfur (S) atom) was prepared for ultrasensitive detection and efficient removal of mercury ions (Hg²⁺). The -NH- group and S atom can capture free Hg²⁺ by coordination and chelation interaction, and the related steric hindrance effect reduces the photocurrent signal of the TFPB-APTU COF, resulting in the highly sensitive photoelectrochemical analysis of Hg²⁺ with a wide linear response range (0.01-100000 nM) and low detection limit (0.006 nM). On the other hand, the developed TFPB-APTU COF has large removal capacity (2692 mg g^-1), good regeneration capability, and high removal speed for Hg²⁺ removal based on the double active sites (-NH- group and S atom), large specific surface area and porous spherical structure. The developed TFPB-APTU COF spheres show great potential in monitoring and treatment of environmental pollution of Hg²⁺.