Abstract: Yttrium ion (Y³⁺)doped titanium dioxide (TiO₂) pillared bentonite was prepared by the acid sol method, and it was used to photocatalytic degradation of methyl orange (MO). The intermediate products and catalysts were analyzed by ultravioletVisible spectrophotometry (UV-Vis), liquid chromatographymass spectrometry (LC-MS), and ultravioletVisible diffuse reflectance spectroscopy (UVVis DRS) during the degradation process, the changes of chemical oxygen demand (COD), total organic carbon (TOC), conductivity, and pH value during degradation were studied. The results show that after 6 h of reaction, the solution is basically colorless, and degradation rate is 99.6%. During the reaction, toluenesulfonic acid, aniline, hydroquinone and other intermediate products are generated, which continue to degrade and mineralize as the reaction proceed. To the end of the reaction, the pH value of the solution decreases from 5.0 to 4.6, the conductivity increases from 82.60 μS/cm to 14150 μS/cm, the COD value of the supernatant decreases from 80.20 mg/L to 12.20 mg/L, [JP+1]the COD value of the suspension decreases from 201.20 mg/L to 102.90 mg/L, the TOC value of the solution decreases from 30.20 mg/L to 13.10 mg/L, and the TOC value of the catalyst decreases from 76.80 mg/L to 43.10 mg/L. The reaction process is carried out according to the synergistic mechanism of adsorption photocatalysis.

Key words: pillared bentonite, photocatalysis, methyl orange, adsorption, synergistic mechanism