Enhanced degradation of amiloride over Bi2FeNbO7/bisulfite process: Key factors and mechanism

Construction of Bi 2 FeNbO 7 /bisulfite system for abatement of pharmaceutical residue was achieved. An attempt to synthesize Bi 2 FeNbO 7 through hydrothermal technique was confirmed by X-ray diffraction. The magnetic field experiment revealed that Bi 2 FeNbO 7 possessed a saturation magnetization of 6.99 emu/g, indicating magnetic attributes of Bi 2 FeNbO 7 . Scanning electron microscopy images showed that Bi 2 FeNbO 7 exhibited regular octahedra in the size of 200–300 nm. In a self-made device, the activation of sodium bisulfite using Bi 2 FeNbO 7 for the disposal of amiloride has been carefully explored. The effects of solution pH, sodium bisulfite concentration, Bi 2 FeNbO 7 dosage, amiloride concentration, coexisting ions, and water matrix on the performance of Bi 2 FeNbO 7 /bisulfite system was investigated. The catalytic performance of Bi 2 FeNbO 7 /bisulfite to degrade amiloride was considerably higher than that of traditional iron oxides . The maximum removal efficiency of amiloride was 97.9% in Bi 2 FeNbO 7 /bisulfite process. The involvement of Fe might be crucial for activating bisulfite to create active species. The dominating radical in Bi 2 FeNbO 7 /bisulfite process was identified as SO 3 •‒ . With the help of UHPLC/MS/MS, three new degradation products of amiloride were found. Dehalogenation and deamination of amiloride might account for the formation of these transformation products . This work provides a highly efficient Bi 2 FeNbO 7 /bisulfite process for the disposal of pharmaceutical pollutants in water treatment .