Photocatalytic degradation of reactive dye RED-3BA in aqueous TiO2 suspension under UV-visible light

The photo‐catalytic degradation efficiency of several commercial titania powders (Degussa P‐25 and Ishihara Sangyo ST‐01) and of TiO 2 supported on diatomite were investigated in the degradation of a reactive dye (RED‐3BA) under UV‐Visible light. The observed rate constant for Degussa P‐25 was found to be higher than that achieved by using Ishihara Sangyo ST‐01 (k obs = 3.3 × 10 −2 min −1 for Degussa P‐25 and 4 × 10 −4 min −1 for Ishihara Sangyo ST‐01). This could be related to the amount of basic hydroxyl groups on the surface of TiO 2 particles as shown in the IR spectra. TiO 2 Degussa P‐25 supported on diatomite was prepared by dip‐coating method. The photo‐catalytic activity of supported TiO 2 was twice smaller than TiO 2 Degussa P‐25 (k p-25 = 3.3 × 10 −2 min −1 ;k p25/diatomite = 1.6 × 10 −2 min −1 ). The higher surface areas of ST‐01 and the TiO 2 /diatomite could not lead to a higher degradation rate and to a higher degree of mineralization but TiO 2 /diatomite could be separated more promptly and more easily from the solution. The effect of pH was investigated in the range 4–9. Acidic (pH = 4) medium was found to favor the adsorption and degradation rate with P‐25 particles.

Abstract licence: CC BY

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