Degradation of bisphenol A in Fe-doped layered double hydroxide activated persulfate systems by enhancing with hydroxylamine hydrochloride

In this study, the degradation of bisphenol A (BPA) was enhanced by adding the reducing agent hydroxylamine hydrochloride (HAHC) into the layered double hydroxides (LDH)/peroxymono- sulfate (PMS) system to promote the conversion of ferric iron (Fe(III)) to Fe(II). The results showed that the degradation efficiency exceeded 90% within 120 min after the addition of HAHC. The effects of initial BPA, PMS concentration, and LDH dosage on BPA degradation efficiency were also evaluated in the HAHC/LDH/PMS system. In addition, the catalyst showed high catalytic activity over a wide pH range (2~10) within the experiment. Radical scavenging tests confirmed that the main reactive oxygen species were sulfate radical (SO4•–), hydroxyl radical (•OH) and superoxide radical (O2•–) in the HAHC/LDH/PMS process. The reaction mechanism was also inferred by using various analytical techniques, including X-ray photoelectron spectroscopy, X-ray diffraction, electron paramagnetic resonance, scanning electron microscopy, transmission electron microscopy, liquid chromatography–mass spectrometry. This work provides a new strategy for the degradation of organic pollutants by the addition of HAHC to promote the activation of PMS by catalysts.