A dielectric barrier Discharge (DBD) plasma catalytic system for synergistic degradation of benzohydroxamic acid (BHA) was established. A series of Er3+-BiOI samples doped with rare earth elements (Er3+) were prepared by the hydrothermal synthesis method. The characterization showed that Er3+-BiOI had a microglobular structure assembled by nanosheets, and the specific surface area of Er3+-BiOI was larger than that of pure BiOI. The degradation performance showed that in the DBD/Er3+-BiOI system, the highest BHA degradation efficiency reached 96.3 % with 4 % Er3+. Compared with the DBD-BiOI system and the single DBD system, the degradation efficiency of BHA increased by 9.1 % and 17.5 %, respectively. Meanwhile, the kinetic constants and cofactors were also the highest, at 3.36 and 2.88 times the DBD-BiOI system, respectively. The radical capture experiments showed center dot OH, center dot O-2(-), and cavities play a key role in the degradation of BHA, while O-3, H2O2, e(-), and H+ promote the degradation of BHA. The intermediates in the degradation of BHA were determined by LC-MS, and the possible degradation pathways of BHA were predicted. Finally, the degradation mechanism of BHA in the DBD/4% Er3+-BiOI system was proposed.
