Photocatalytic decolourization of indigo carmine on 1,10-phenanthrolinium intercalated bentonite under UV-B and solar irradiation

Abstract In the present work, organophilic clay was prepared and characterized by XRD, FT-IR, TGA, 13 C MAS NMR and UV–vis DRS. The obtained material was investigated as photocatalyst on photo-decolourization of indigo carmine under UV-B and solar irradiation. The decolourization capacity of the obtained material against indigo carmine was very low. Besides, the kinetic photo-decolourization data under UV-B and solar irradiation fitted well the pseudo-first order and Langmuir–Hinshelwood kinetic models. The photo-decolourization rate was found better under solar than UV-B irradiation. A total colour removal was obtained at natural pH after 160 min of solar irradiation of a 10 mg L −1 indigo carmine solution. The prepared material was used four times with practically the same decolourization efficiency.