Synthesis and characterization of FeOOH QDs via a one-pot method for effective removal of copper cations from aqueous solutions

Abstract

FeOOH quantum dots (FeOOH QDs) are an emerging material that finds applications in numerous fields. Despite their potential as an alternative material for heavy metal ion adsorption in aqueous solutions, investigations into the properties of FeOOH QDs in this application are scarce. Furthermore, the conventional fabrication process of FeOOH QDs is time-consuming. To address this issue, a novel one-pot strategy using the microemulsion method was developed to synthesize FeOOH QDs with a size of approximately 5 nm within just 30 min. X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), and atomic force microscopy (AFM) were employed to characterize the resulting FeOOH QDs. The adsorption properties and mechanisms for copper cations removal using FeOOH QDs were investigated systematically. The results indicate that copper cations can be adsorbed onto FeOOH QDs surface homogeneously, forming a monolayer via a chemical bond of Cu-Fe-O via a spontaneous and exothermic process. The optimum adsorption capacity of Cu2+ reached 118.78 mg·g−1 at 303 K and pH value of 6.