Photocatalytic activity of kaolinite

The photocatalytic activity of commercial kaolinite (KGa-1b) was evaluated for the degradation of methylene blue (MB) in aqueous suspension and of toluene in the gas phase. An enhanced photolysis of MB in the presence of kaolinite was detected, albeit at a slower rate than in the presence of the same mass of commercial TiO2 P25. Toluene removal under realistic ambient concentrations was catalyzed by both KGa-1b and P25; however, on a TiO2 content normalized basis, the clay mineral showed a higher photocatalytic rate. In the latter case, toluene degradation was found to be coupled to the presence of kaolinite surfaces, and not proportional to TiO2 content.

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► KGa-1b is a natural photocatalytic material
► Kaolinite promotes enhanced photolysis of methylene blue in water
► Kaolinite promotes enhanced photodegradation of toluene in air. Although the overall removal is lower than with P25, it is higher with KGa-1b than P25 on a TiO2 content normalized basis.