Abstract:
In this study, novel green nano-zerovalent iron (G-NZVI) is synthesized for the first time using onion peel
extract for the prevention of rapid surface oxidation and the enhancement of particle dispersibility with
a high reductive capacity. The results from various surface analyses revealed that the spherical shape of
G-NZVI was fully covered by the onion peel extract composed of polyphenolic compounds with C]C–
C]C unsaturated carbon, C]C, C–O, and O–H bonds, resulting in high mobility during column
chromatography. Furthermore, the obtained G-NZVI showed the complete removal of 50 mg L 1 of
bromate (BrO3
) in 2 min under both aerobic (k ¼ 4.42 min 1
) and anaerobic conditions (k ¼
4.50 min 1
), showing that G-NZVI had outstanding oxidation resistance compared to that of bare NZVI.
Moreover, the observed performance of G-NZVI showed that it was much more reactive than other
well-known reductants (e.g., Fe and Co metal organic frameworks), regardless of whether aerobic or
anaerobic conditions were used. The effects of G-NZVI loading, the BrO3
concentration, and pH on the
BrO3
removal kinetics using G-NZVI were also investigated in this study. The results provide the novel
insight that organic onion peel waste can be reused to synthesize highly reactive anti-oxidative
nanoparticles for the treatment of inorganic chemical species and heavy metals in water and wastewater.