Sorption behavior of 6:2 chlorinated polyfluorinated ether sulfonate (F-53B) on four kinds of nano-materials

Abstract

6:2 chlorinated polyfluorinated ether sulfonate (with the trade name F-53B, a substitute for PFOS) is one type of Per- and polyfluoroalkyl substances (PFASs), which is widely used as a chromium mist inhibitor in China. It has been found in environment commonly. In this study, the sorption behavior of F-53B on four kinds of nano-materials: alumina nanopowder (ANP), alumina nanowires (ANW), hydrophilic bentonite nanoclay (HBNC) and surface modified nanoclay (SMNC) were investigated. The kinetics results indicated that the sorption of F-53B on four nano-materials reached equilibrium within 2 h and the sorption process were fitted better by the pseudo-second-order kinetic model than the pseudo-first-order kinetic model. The thermodynamic study showed that the sorption of F-53B on nano-materials were exothermic and spontaneous. As the increase of temperature, the maximum sorption capacity of ANP, ANW, HBNC, SMNC increased, and reached 868.75, 91.35, 5.15, 2465.09 μg/g at 25 °C, respectively. The surface modified nanoclay (SMNC) was better than the others for removing F-53B from aquatic environment. To investigate the effects of pH and ion strength, the particle size and zeta potential of sorbents at different pH and ion strength were measured by Dynamic Light Scattering (DLS), and concluded that the sorption mechanism of F-53B on two kinds of nanoalumina mainly included electrostatic attraction and agglomeration effects, while hydrophobic interaction played an important role on the sorption of F-53B on nanoclay. This study revealed the sorption behavior and mechanism of F-53B on four kinds of nano-materials, and the results provided theoretical support for removing F-53B from electroplating wastewater with nano-materials.