BiOI microspheres were synthesized using solvothermal method for the degradation of residual xanthate and gaseous nitric oxide (NO) under visible light irradiation. The as-prapared BiOI nanomaterials are then characterized using various technologies including XRD, FE-SEM, TEM, UV-vis DRS and XPS. The photodegradation results show that the removal efficiency of isobutyl sodium xanthate can reach 98.08 % at initial xanthate concentration of 120 mg/L; that of NO is as high as 96.36 % at inlet NO concentration of 11 ppm. Moreover, the effects of operational parameters such as catalyst dosage, initial xanthate concentration, and pH value of wastewater on the removal of xanthate were investigated. The results of scavenging tests and full-spectrum scanning indicate that ·O₂^- radicals are the main active species in xanthate degradation, and peroxide xanthate is an intermediates. The reusability of BiOI was explored through cyclic experiments. Furthermore, the reaction path and mechanism of NO removal using BiOI were analyzed, and the main active species is also ·O₂^-. It is concluded that BiOI photocatalysts have high potentials for wastewater treatment and waste gas clean-up in mineral industry.

BiOI microspheres, photocatalytic degradation, xanthate, nitric oxide