Adsorption of carbon dots onto Al₂O₃ in aqueous: Experimental and theoretical studies

Increasing interests in carbon dots (CDs) research resulted in the increased production of CDs and the risk to be released into the environment, including surface water and groundwater. To assess the environmental behavior of CDs, the stability of CDs in aqueous solutions were first examined by different environmental conditions, followed by the systematic investigation of the adsorption behaviors of CDs onto Al₂O₃ surface. Electrostatic interactions were considered as the dominant forces in CDs adsorption onto Al₂O₃ process, which were further confirmed by controlling experiments as compared with other minerals or oxides, such as montmorillonite, kaolinite and SiO₂. Theoretical calculations and characterization of Al₂O₃/CDs revealed chemisorptions exist in the adsorption process. Our investigation results provided fundamental understanding towards the interaction of CDs with Al₂O₃ surface, and potential fate of CDs under natural conditions in aquatic environment, as well as in soils and sediments.