GO accelerate iron oxides formation and tetrabromobisphenol A removal enhancement in the GO loaded NZVI system.

Tetrabromobisphenol A (TBBPA) is an emerging persistent organic pollutant, which is very difficult to remove by common methods. In this study, the GO-load nanoscale zero-valent iron (NZVI/GO) was fabricated and optimized to improve the reaction rate and removal efficiency for TBBPA reliably and efficiently. The results showed that GO-load significantly reduced the self-aggregation of NZVI and the aggregate size decreased by 50.00% (1400-700 nm). Meanwhile, GO significantly improved the reaction rate kobs (1.11 ± 0.11 h-1) of TBBPA in the NZVI/GO system compared to the NZVI (0.40 ± 0.08 h-1) system, and this increment was more pronounced (177.5%) when the mass ratio of NZVI-to-GO reached 1.0 than other mass ratios. Furthermore, X-Ray Diffraction and X-ray photoelectron spectroscopy analysis suggested that the Fe2+ transformation was changed and enriched by the GO. Only magnetite (Fe3O4) was detected on the surface of NZVI, whereas the maghemite (γ-Fe2O3), hematite (α-Fe2O3), and Fe3O4 were detected on the interface of NZVI/GO, which further performed the complexation adsorption through the -OH of TBBPA. This specific complexation adsorption is another potential accelerated removal mechanism for TBBPA and intermediates within the NZVI/GO system. This research has put forward a new perspective for widening the application of TBBPA removal using the synergistic effect between GO and NZVI.