Degradation of TBBPA and BPA from aqueous solution using organo-montmorillonite supported nanoscale zero-valent iron

Abstract

Organo-montmorillonite supported zero-valent iron nanoparticles (Fe0/OMt) with well-dispersion and higher specific surface area were synthesized for the degradation of tetrabromobisphenol A (TBBPA) and bisphenol A (BPA) in aqueous solution. X-ray powder diffraction (XRD), Brunauer-Emmett-Teller (BET), transmission electron microscopy (TEM), Energy-Dispersive X-ray elemental mapping, and X-ray photoelectron microscopy (XPS) were used to characterize the composition and microstructures of Fe0/OMt. Interestingly, nanoscale zero-valent iron (Fe0) core with a uniform iron oxide shell are formed and well dispersed on the organo-montmorillonite supports. After systematical optimization of treatment conditions, Fe0/OMt (0.1g/L) with sparging O3 (concentration of 4mg/L) demonstrated excellent degradation efficiency for TBBPA and BPA (98.6% and 94.7%, respectively) with the initial concentration of 10mg/L. Notably, in the aforementioned oxic conditions, bromide ions, ferrous ion, and hydroxyl radicals were detected during the progressive degradation of the TBBPA and BPA, suggesting that TBBPA was debrominated as the primary step then completely mineralized by oxidative process. Finally, combined with the analysis of degradation products identified by LC–MS, pathways of TBBPA and BPA over Fe0/OMt were proposed. These results revealed that a Fe0/OMt based on advanced oxidation technology is of great potential for remediating TBBPA and BPA in aqueous environment.