Core–Shell Magnetic Amino-Functionalized Microporous Organic Network Nanospheres for the Removal of Tetrabromobisphenol A from Aqueous Solution

Abstract

Development of functional porous materials for efficient elimination of environmental pollutants is of great importance in green chemistry and environmental protection. Here we report the design, synthesis, and application of a core–shell magnetic amino-functionalized microporous organic network nanosphere (Fe3O4@MON-NH2) for efficient magnetic adsorption of a typical brominated flame-retardant tetrabromobisphenol A (TBBPA) from aqueous solution. By integration of the hydrophobic networks and hydrogen binding sites within MON-NH2, the synthesized core–shell Fe3O4@MON-NH2 nanospheres gave good adsorption for TBBPA. The adsorption equilibrium of TBBPA (50 mg L–1) on Fe3O4@MON-NH2 was achieved within 1 min, showing ultrafast adsorption kinetics of Fe3O4@MON-NH2 for TBBPA. The adsorption of TBBPA on Fe3O4@MON-NH2 followed the pseudo-second-order kinetics and Langmuir adsorption models, giving a maximum adsorption capacity of 135.9 mg g–1 at 25 °C. The adsorption of TBBPA on Fe3O4@MON-NH2 was a spontaneous and endothermic process controlled by positive entropy. Encouraged by the large adsorption capacity, rapid adsorption kinetics, and the small effect of pH (5–10), dissolved organic matter, and ionic strength on the adsorption, the application of Fe3O4@MON-NH2 for TBBPA removal in real water samples was achieved. The used Fe3O4@MON-NH2 can be easily regenerated and reused at least four times without significant reduction of the adsorption capacity. These results revealed the potential of Fe3O4@MON-NH2 for adsorption and removal of environmental pollutants from aqueous solution.