High-performance FeOOH quantum dots: A novel one-pot microemulsion method for fast preparation and adsorption kinetics

As an emerging material, FeOOH quantum dots (QDs) are being used for their applications in the photodegradation of organic pollutants. However, as a promising adsorbent for the removal of dyes from aqueous solution, their adsorption performance has not yet been studied, and the fabrication of FeOOH QDs typically involves a time-consuming process. To improve its preparation efficiency, a one-pot microemulsion method for the fast fabrication of FeOOH quantum dots was successfully developed, by which FeOOH QDs of approximately 5 nm were successfully prepared within 30 min. The as-synthesized FeOOH QDs were characterized by XRD, XPS, BET, HR-TEM, and AFM. The adsorption properties of the FeOOH QDs for methyl orange (MO) were investigated, and the adsorption mechanism was studied via adsorption kinetics and adsorption isotherms. The results indicated that the adsorption of MO onto FeOOH QDs was a chemisorption process that follows the Langmuir isotherm. The FeOOH QDs possess a high BET surface area of 97.24 m2/g and can achieve a maximum adsorption capacity (qm) of 167.22 mg/g for MO, as estimated by the Langmuir isotherm. The adsorption performance of FeOOH QDs is better in acidic solution than it is in basic solution, and the FeOOH QDs show good stability and reusability.