Hydroxylamine-facilitated removal of organic pollutants by the Fenton process

The traditional Fenton process cannot efficiently remove organic pollutants because of the low recycling efficiency of Fe2+. Hydroxylamine (HA) is a typical reducing agent that can accelerate the Fe2+ cycle. Thus, the HA-facilitated Fe2+/H2O2 removal of tartrazine was investigated. Only 31.4% tartrazine could be removed within 10 min with the Fe2+/H2O2 system, while 76.9% tartrazine could be removed with the Fe2+-HA/H2O2 system. The value of k for removing tartrazine with the Fe2+-HA/H2O2 system was 4.3-fold higher than that for removing tartrazine with the Fe2+/H2O2 system; the effect of various factors, such HA dosage (0–8 mM), initial pH (3–6), Fe2+ dosage (0–0.4 mM) and H2O2 dosage (1–16 mM), on the tartrazine removal with the Fe2+-HA/H2O2 system were also examined. The optimal HA, Fe2+, and H2O2 dosages were 4, 0.2 and 8 mM, respectively. The Fe2+-HA/H2O2 process could also broaden the working pH range from 3–4 to 3–6 for wastewater treatment. In addition, the tartrazine removal performance of the Fe2+-HA/H2O2 process was better in the presence of inorganic ions and natural organic matter. Moreover, the Fe2+-HA/H2O2 process could remove a wide range of organic pollutants efficiently and significantly improved of the performance of the Fe2+/H2O2 process. Therefore, this study could improve our understanding of the effect of HA on promoting pollutant elimination with the Fe2+/H2O2 process.