Self-assembly of mesoporous Bi-S-TiO₂ composites for degradation of industrial dinitrotoluene solution under UV light

Mesoporous Bi-S-TiO₂ composites were synthesized by the method combining evaporation-induced self-assembly (EISA) method with impregnation process. Characterization shows mesoporous Bi-S-TiO₂ was a highly crystalline anatase, with relatively high thermal stability, large surface area (75-120 m²/g), and large mesopore (10-20 nm). The results also revealed that Bi and S species existed in Bi⁴⁺, S^2-, S and S⁶⁺ forms in the mesoporous TiO₂, which allow the mesoporous Bi-S-TiO₂ illustrating strong absorption in the ultraviolet region, and the absorption edge shifts to the visible-light region. Photodegradation tests shown that, about 92.3% industrial aqueous dinitrotoluene (DNT) solution could be degraded by 1.5%Bi-S-TiO₂ under UV irradiation for 5 h. Concentration of Bi ions and calcination temperature were found to play important roles in its mesoporous properties and photocatalytic activity.