Thiol grafted imine-based covalent organic frameworks for water remediation through selective removal of Hg(ii)Electronic supplementary information (ESI) available: Experimental procedures and characterization data for all compounds. Synthesis, NMR and FTIR spectra, UV-vis, TGA, PXRD profiles, SEM and TEM images, EDS, Hg(ii) measurements and XPS spectra. See DOI: 10.1039/c7ta05588a

An imine-linked covalent organic framework ( [HC&z.tbd;C] 0.5 -TPB-DMTP-COF ), endowed with reactive ethynyl groups on the walls of one-dimensional pores, has been used as a platform for pore-wall surface engineering with triazole and thiol groups to yield TPB-DMTP-COF-SH , which is suitable to interact very efficiently with mercury ions. The evaluation of the carefully designed TPB-DMTP-COF-SH is addressed as an effective and selective system for mercury sorption. The obtained results reveal an extraordinary capacity and a great efficiency of the polymeric material with a very high distribution coefficient value K d = 3.23 × 10 9 . Thus, the level of mercury of a highly concentrated aqueous solution, 10 mg L −1 of Hg( ii ), is dramatically decreased, below the limits of what is considered to be drinking water, upon treatment with TPB-DMTP-COF-SH for a few minutes. The TPB-DMTP-COF-SH retention value of Hg( ii ) from water is 99.98% within 2 minutes and its record uptake capacity is 4395 mg g −1 which represents the highest value reported so far. Besides TPB-DMTP-COF-SH captures other extremely toxic heavy metal ions such as Sn( ii ) and Pb( ii ) being quite selective versus Cd( ii ) or As( iii ). These results suggest that TPB-DMTP-COF-SH constitutes a realistic alternative for the remediation of contaminated spaces from an environmental perspective. An outstanding and selective material for Hg( ii ) polluted water remediation based on an imine-linked COF endowed with triazole and thiol groups.