A strategy of eliminating phosphate inhibiting the degradation of metronidazole by hydroxylamine assisted heterogeneous Fenton-like system

The heterogeneous Fenton-like process using hydroxylamine (HA) possessed the merit of rapid oxidation performance is very fascinating for water treatment. However, the existence of phosphate limits the oxidation rate of organic pollutants. This study uncovered the role of phosphate in HA-assisted Fenton-like process and provided a feasible strategy to dispel the negative influence of phosphate upon introduction of aluminum and ferric ions. Besides, optimized reaction conditions as nMET of 0.04 g/L, H2O2 of 1.3 mM and HA of 0.4 mM were acquired by response surface methodology (RSM) with MNZ degradation efficiency of 95.21% and leaching Fe ions of 2.26 mg/L. Hydroxyl radical (HO center dot) and superoxide radical (O-2(-center dot)) were responsible for MNZ removal. Subsequently, the toxicities assessment of formed MNZ byproducts was clarified based on the analysis of MNZ decomposition pathways.

Automated summary

The heterogeneous Fenton-like process using hydroxylamine (HA) is attractive for water treatment due to its rapid oxidation performance. However, the presence of phosphate limits the oxidation rate of organic pollutants. This study elucidated the role of phosphate in the HA-assisted Fenton-like process and provided a feasible strategy to mitigate its negative influence.