Study of adsorption properties of functionalized nanodiamonds in aqueous solutions of metal salts using optical spectroscopy

This paper presents results of a study of adsorption properties of the original (I6) and carboxyl-modified (I6COOH) detonation nanodiamonds (DNDs) dispersed in aqueous solutions, with respect to dissolved ions: Cu2+, Pb2+, NO3-. Application of complementary spectroscopic methods allows comparative analysis of the adsorption activity of DNDs in aqueous solutions of metal salts. It was shown that both types of functionalized NDs readily adsorb nitrate ions and metal cations, and the adsorption efficiency of I6COOH is approx. three times higher than that of I6. Hypothetic mechanism of nitrate and copper ions adsorption on NDs surface is proposed.

► Modification of ND by COOH increases its adsorption activity to ions Cu, Pb, NO3.
► The ND adsorption in aqua solutions was studied by four methods of optical spectroscopy.
► The mechanisms of adsorption of nitrate ions on the NDs surface are explained.
► The mechanisms of adsorption of copper cations on the NDs surface are explained.