Tailored rapid recognizer and adsorbent of ultra-trace Hg²⁺ with novel benzothiazol-group decorated covalent organic polymers

Porous materials for fast detection and adsorption of Hg2+, due to their good sensitivity and high adsorption capacity, were currently developed as one of the best ways to solve Hg2+ pollution. Inspired by the structure of small-molecule B-1 demonstrating specific recognition towards Hg2+, the covalent organic polymers (COPs) material TB-COP was constructed for a better demonstration of Hg2+ detection and adsorption. The results indicated that TB-COP could accomplish rapid detection of Hg2+ in about 90 s, with a good linearity (R-2 = 0.9993) and high sensitivity (LOD = 36 nM). Because the electron transfer between N and S atoms in the benzothiazole moiety, the recognition of TB-COP towards Hg2+ was achieved, which was further proved by DFT calculation. Though the COPs possess its excellent fluorescence properties, the saturated adsorption capacity for Hg2+ by TB-COP reached 150.38 mg.g(-1) at pH = 7. More importantly, TB-COP could be approximately recycled 5 times in the Hg2+ adsorption-desorption cycle at room temperature, providing a new strategy to solve Hg2+ pollution.