Hydroxylamine-facilitated degradation of rhodamine B (RhB) and p-nitrophenol (PNP) as catalyzed by Fe@Fe2O3 core-shell nanowires

Fe@Fe2O3 core-shell nanowire is a promising heterogeneous Fenton iron catalyst to degrade organic pollutants. So far, the roles of hydroxylamine (HA) in Fe@Fe2O3/HA system for pollutant degradation still remain unknown. In this study, the HA-facilitated degradation of rhodamine B (RhB) and p-nitrophenol (PNP) by Fe@Fe2O3 was reported and the underlying mechanisms were explored. Results show that addition of HA significantly enhanced degradation of organic pollutants and a higher HA dosage caused a faster degradation rate. The degradation process was completely inhibited by scavengers, indicating the hydroxyl radical (HO center dot) from bulk solution dominated the reactions. HA in the Fe@Fe2O3/H2O2/HA system was highly efficient to promote the generation of HO center dot by accelerating both the Fe3+/Fe2+ cycle and the H2O2 decomposition. Meanwhile, HA itself was rapidly decomposed along with the pollutants degradation. About 50.5% of RhB and 46.4% of PNP were mineralized in the presence of HA. The effective pH value for degradation was expanded from 4.0 to 5.0. The EE/O calculations demonstrate that a higher energy input for PNP was required than that for RhB. This study will shed lights on the reactivity of the Fe@Fe2O3/HA system and provide an alternative pathway for removal of organic contaminants. (C) 2019 Elsevier B.V. All rights reserved.