Photocatalytic Degradation of Acridine Orange over NaBiO3 Driven by Visible Light Irradiation

The photocatalytic degradation of acridine orange (AO) dye by NaBiO3 photocatalyst under visible light irradiation was investigated systematically. The NaBiO3 photocatalyst exhibited a higher photocatalytic activity compared to the P25 photocatalyst. After 160 min of photocatalytic reaction, the degradation rate of AO could reach to 99% in appropriate conditions. Factors, such as catalyst dosage, solution pH, initial AO concentration and the presence of anions, were found to influence the degradation rate. To scrutinize the mechanistic details of the dye photodegradation, the intermediates of the processes were separated, identified and characterized by the HPLC-ESI-MS technique. The analytical results indicated that the N-de-methylation degradation of AO dye took place in a stepwise manner to yield mono-, di-, tri- and tetra-N-de-methylated AO species generated during the processes. The probable photodegradation pathways were proposed and discussed.