Peracetic acid activation by natural magnetite for bisphenol A degradation: Performance and degradation mechanism

Advanced oxidation processes based on activated peracetic acid (PAA) have been widely used in water treatment. In this study, magnetite was first employed in PAA activation for Bisphenol A (BPA) degradation. The results showed that the magnetic/PAA system degraded 94.6 % BPA in 60 min at neutral pH (pH = 6.7), exhibiting a higher rate constant ( k obs = 0.051 min −1 ) than PAA or magnetite alone. X-ray photoelectron spectroscopy (XPS) results proved that ≡Fe(II) and surface hydroxyl group (O OH ) were the dominant active sites, which promoted the electron transfer between magnetite, PAA, and BPA. According to the scavenging experiments and electron paramagnetic resonance (EPR) spectrum, the main reactive oxygen species responsible for BPA degradation include organic radicals ( CH 3 COOO), Hydroxyl radical ( OH) and singlet oxygen ( 1 O 2 ). The BPA degradation pathway was determined by LC-MS analysis, and the toxicity of the intermediates was evaluated by ECOSAR and wheat seed growth inhibition experiment. In addition, the magnetite/PAA system presented a good adaptability under a wide initial pH range, demonstrating efficient degradation even in the presence of complex matrices such as Cl − , NO 3 − or humic acid in water bodies while HCO 3 − and H 2 PO 4 − inhibited BPA degradation. This study not only reveals the mechanism of magnetite activating PAA but also provides a new idea for applying magnetite in PAA-based AOPs to remove micropollutants in wastewater. • Natural magnetite could effectively activate PAA for Bisphenol A degradation. • Fe(II) and surface hydroxyl group (O OH ) on magnetite surface were responsible for PAA activation. • OH, CH 3 C( O )OO and 1 O 2 were evidenced as the dominant reactive species for BPA degradation. • The toxicity of the intermediates was lower than that of BPA. • The influence of water matrices in the magnetite/PAA system was distinguished.