Photocatalytic degradation of Chicago Sky Blue 6B and Benzopurpurin 4B using titanium dioxide thin film

Article type: Research Article

Authors: Mohammed, Abdul K. | McKenzie, Katrina T.

Affiliations: Department of Chemistry, Winston-Salem State University, 601 S. Martin Luther King, Jr., Drive, Winston-Salem, North Carolina 27110, USA | Department of Chemistry, North Carolina Agricultural and Technical State University, 1601 E. Market Street,Greensboro, North Carolina 27411, USA

Note: [] Corresponding author. E-mail: [email protected]

Abstract: Aqueous solutions of azo dyes undergo degradation to form harmless intermediates and colorless products following irradiation by visible light in the presence of titanium dioxide thin films. The dyes that were studied in this work are: Chicago Sky Blue 6B and Benzopurpurin 4B. Results obtained indicated that complete mineralization of the dyes took place under the experimental conditions. There was an increase in conductivity after the complete mineralization experiments possibly indicating the formation of ions such as NO_3^- and SO^{2-}_4. Chemical oxygen demand (COD) measurements show a decrease in organic matter for both dyes following complete degradation. The effect of how changing experimental conditions such as pH, temperature and starting concentrations of dyes affected the rate of dye degradation was measured. There was an increase in the rate of disappearance of the dye color at lower pH. High concentrations of dye solutions required long degradation time.

Keywords: titanium dioxide, photocatalysis, photocatalytic degradation, azo dyes

Journal: Journal of Environmental Sciences, vol. 17, no. 5, pp. 869-872, 2005