COF_(BTLP-1)/three-dimensional macroporous carbon electrode for simultaneous electrochemical detection of Cd~(2+), Pb~(2+), Cu~(2+) and Hg~(2+)

摘要

The indissolubility or poor dissolubility of covalent-organic frameworks (COFs) limits their wide applications. Here, the COF_(BTLP-1) which were prepared by the aminaldehyde condensation between 1,4-benzenedithiol-2,5-diamino-hydrochloride and 1,3,5-triformylbenzene was controllably grown on kenaf stem-derived macroporous carbon (3D-KSC). Compared with COF_(BTLP-1) powder, the COF_(BTLP-1) grown on 3D-KSC avoided their random orientation effectively. The results showed that the amount of COF_(BTLP-1) could be effectively controlled by adjusting the concentration of monomers and growing time. Each unit of COF_(BTLP-1) has 12 adsorption sites (6 sulfur atoms and 6 nitrogen atoms) for heavy metal ions (HMIs) and regular holes to facilitate the transfer of HMIs. A large number of adsorption sites of HMIs could identify and captured HMIs selectively, and accordingly Cd~(2+), Pb~(2+), Cu~(2+) and Hg~(2+) could be detected simultaneously by using the COF_(BTLP-1)/3D-KSC electrode. The detection limits for Cd~(2+), Pb~(2+), Cu~(2+) and Hg~(2+) are 12.3 nM, 11.8 nM, 18.6 nM and 21.4 nM, respectively. The sensitivities are up to 1337.4 μA/pM cm~2, 1389.0 μA/μM cm~2 and 886.2 μA/μM cm~2, 770.0 μA/μM cm~2, respectively. The COF_(BTLP-1)/3D-KSC may be also applied in other fields of electroanalytical chemistry.