Abstract: The residual xanthate in flotation wastewater will seriously endanger the natural ecology and environment.In order to degrade xanthate efficiently,TiO2/montmorillonite(MMT) composite materials were prepared by grinding and sintering method based on the principle of solid diffusion.XRD,FTIR,SEM,UVVis spectroscopy and PL spectroscopy were used to characterize the structure,morphology and photochemical properties of the obtained composites.The effects of TiO2 loading amount,catalyst dosage,initial concentration of butyl xanthate and xanthate type on its photocatalytic degradation performance were investigated under UV irradiation.The photocatalytic degradation mechanism of butyl xanthate was proposed through the active group scavenging experiment and realtime absorbance curves of simulated wastewater.The results showed that 80%TiO2/MMT had higher ultraviolet absorption performance and lower recombination rate of photogenerated carriers.Under the conditions of 0.2 g/L catalyst dosage and 20 mg/L initial concentration of butyl xanthate,the photocatalytic degradation rate of butyl xanthate reached as high as 99.52% after 30 minutes of irradiation.The composite materials showed excellent reusability and could degrade multiple xanthates.·O2- and h+ were the main active substances for photocatalytic degradation of butyl xanthate,and peroxy xanthate was produced as intermediate product in the photocatalytic process.

Key words: TiO₂, montmorillonite, solid diffusion, xanthate, photocatalytic degradation