Introducing Selectivity on Carbonaceous Material: Removing Noble Salts, Au3+, and Ag+ from Aqueous Media by Nanodiamonds Functionalized with Squaramides

Abstract

Nanodiamonds coated with dopamine−squaramide compounds have been prepared by a calcination/esterification synthetic process, which improves the efficiency of this carbonaceous material with respect to non-functionalized nanodiamonds. The modified nanodiamonds show excellent selective coordination of Ag + and Au 3+ cations in a Cd 2+ , Co 2+ , Cr 3+ , Cu 2+ , Pb 2+ , and Zn 2+ mixture in water. The coordination capacity of the carbonyl squaramide groups with the silver and gold cation is based on purely electrostatic cation−dipole interactions. Overall, it is demonstrated that the conjunction between the nanodiamonds and the organic receptor improves the selectivity of the material toward noble cations.