Influence of surfactant on the fast photodegradation of rhodamine B induced by TiO2 dispersions in aqueous solution

The photodegradation of dyes under visible light irradiation represents an important step in the study of advanced oxidation processes (AOP). The sensitization of dyes and surface modification of titanium dioxide with adsorption of dyes promote the electron transfer from excited dyes to the conduction band of semiconductor, optimizing and accelerating the dye degradation. In this direction, we report the use of an anionic surfactant (sodium dodecyl sulphate) which promotes the dimerization of rhodamine B and subsequent adsorption on the TiO2 surface. As a result, it is verified that extremely reduced concentration of titanium dioxide (2 × 10−5 g/mL) is sufficient to provide the photodegradation of dye in scale of minutes.

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► Fast photocatalysis in the visible region is induced by surface modification of TiO2.
► The action of SDS induces dimerization of rhodamine B.
► The sensitization of rhodamine B maximizes the electron transfer to the conduction band of TiO2.
► Presence of SDS and TiO2 induces photodegradation of rhodamine B in a few minutes.