Photocatalytic degradation of methyl orange by Bi20TiO32–montmorillonite composite

摘要

To solve the problem of methyl orange (MO) dye wastewater pollution, TiO2-montmorillonite composite (TiO2-MMT) and Bi20TiO32-montmorillonite composite ( Bi20TiO32-MMT) were synthesised by the sol-gel method, and they were used for photocatalytic degradation of MO solution. The results showed that TiO2 in TiO2-MMT existed as the anatase type, and Bi20TiO32 in Bi20TiO32-MMT existed as the tetragonal crystal type. When the dosage of the composite was 0.50 g/l, the initial concentration of the MO solution was 20 mg/l, and the pH was 3, the decolourisation rate of MO solution using TiO2-MMT treating was 87.11%, and it reached 98.50% after Bi20TiO32-MMT treating. When Bi20TiO32 Bi20TiO32 -MMT was reused four times, the decolourisation rate of the MO solution was only reduced by 3.5%. The photocatalytic degradation between MO solution and Bi20TiO32-MMT complied with the pseudo-first-order kinetic equation. Holes and superoxide radicals interacted directly with MO during photocatalytic degradation, which reduced the probability of hole-electron recombination, and improved the photocatalytic degradation property of Bi20TiO32-MMT. Bi20TiO32-MMT has excellent stability property, which makes it a good composite in the treatment of dye wastewater.