Synergistic degradation of Orange G in water via water surface plasma assisted with β-Bi2O3/CaFe2O4

A coupling method of water surface plasma (WSP) with β -Bi 2 O 3 /CaFe 2 O 4 composite was applied to promote the elimination of aqueous Orange G (OG). The morphology, structures, crystal form and chemical bonding state of the prepared β -Bi 2 O 3 /CaFe 2 O 4 composite were characterized via SEM, TEM, EDS-mapping, XRD, FT-IR and XPS. The results showed that the addition of composites significantly enhanced the degradation and kinetic constant of OG. The degradation efficiency of the combined system containing 8.0 wt% β -Bi 2 O 3 /CaFe 2 O 4 composite was 28.9% higher compared to the sole WSP for OG degradation. The synergistic factor (2.387) demonstrated that the combined system was able to establish a synergistic effect. The effect including peak voltage, air flow rate, initial conductivity and initial concentration of solution on OG removal was inspected. The active species trapping experiments demonstrated ·OH, h + , ·O − 2 and high-energy electrons devoted to OG removal in the combined system. O 3 and H 2 O 2 were also involved in the OG removal in the combined system. Three-dimensional fluorescence spectroscopy and liquid chromatography-mass spectrometry were tested to investigate the mechanism of OG degradation. Finally, the combined system in the present study was compared with other competitive technologies for the degradation of OG in the literature.