Simultaneous adsorption of hydrophilic and lipophilic dyes on iron-doped hydroxyapatite/carbon dots nanocomposites

Nanocomposites of iron-doped hydroxyapatite and carbon dots were synthesized through green synthesis processes, using Yerba Mate (Ilex paraguariensis) as a precursor. A thorough characterization of the particles was carried out by HRTEM, XRD, FTIR, DLS, XPD, and static contact angle. The characterization indicated that the crystallinity, surface charge, and wettability depend on the synthesis parameters. Carbon dots-doped materials, [email protected] and [email protected], showed amphiphilic properties with the capacity to adsorb Crystal violet (CV) and Oil Blue A (OBA) from aqueous or toluene-based solutions. The mentioned materials showed the highest number of adsorption sites, with values of 2.95 ± 0.05 and 3.18 ± 0.04 mmol CV/gads and 1.65 ± 0.02 0.97 ± 0.06 mmol OBA/gads on monocomponent systems, and through a multi-component analysis, the competition for adsorption sites was elucidated.