Highly effective adsorption removal of perfluorooctanoic acid (PFOA) from aqueous solution using calcined layer-like Mg-Al hydrotalcites nanosheets.

Abstract

To study the influence factors of calcined layer-like Mg-Al hydrotalcites nanosheets adsorbing perfluorooctanoic acid (PFOA) in aqueous solution, Mg-Al hydrotalcite (HMA) nanosheets were prepared by one-step hydrothermal synthesis. The effect of calcination temperature on adsorption properties and structure of HMA (CHMA-x, x means different calcination temperature) was investigated. The prepared samples were systematically characterized by the Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG), X-ray diffraction (XRD), scanning electronic microscopy (SEM), and nitrogen adsorption-desorption isotherms. The adsorption isotherms and kinetics showed the adsorption equilibrium reached within 2h, and the factors, such as adsorption dosage, pH, and cycles were investigated. It was found that CHMA with 600°C displayed a uniformly morphology, higher surface area about 106.3m2/g, and excellent adsorption properties (1969mg/g). The equilibrium adsorption data perfectly fitted to the pseudo-second-order kinetic model (R2 = 0.999) and the Freundlich model (R2 = 0.994). The main mechanism of CHMA adsorbing PFOA might be the "memory effect." This study provided a new insight to prepare highly effective adsorbents in water treatment.