A covalent organic framework bearing thioether pendant arms for selective detection and recovery of Au from ultra-low concentration aqueous solution.

A fluorescent covalent organic framework (COF), featuring precise distribution of thioether pendant arms inside the cavity, was designed. The thioether-functionalized COF exhibits selective sensing and capture of Au ions at ultra-trace levels in water with high sensitivity, selectivity and adsorption capacity, which makes it an excellent candidate for selective detection and recovery of Au.