Abstract: The photocatalytic activity of kaolin/ZnO composites prepared by calcination was investigated. The proposed synthesis procedure comprises the reaction of ZnCl2 with Na2CO3 in water dispersion of kaolin KKAF. Precursor sodium zinc carbonate Na2Zn3(CO3)4·3H2O is formed and after its thermal decomposition the nanostructured ZnO is formed. Using this procedure the kaolin/ZnO composites containing ~6 and ~39 mass% of ZnO were prepared. X-ray fluorescence was used for determination of the ZnO yield. Phase composition of composites thermally treated at 100–600°C was studied using X-ray diffraction method. UV-VIS diffuse reflectance spectroscopy was used to determine the band gap energy of prepared composites and their photocatalytic activity was tested by discoloration of Acid Orange 7 in aqueous solution. Composite containing ~39 mass% of ZnO and calcined at 600°C exhibits the highest photocatalytic activity. Leaching tests proved that the composites can be considered non-hazardous.

Janíková B., Tokarsk J., Mamulová Kutláková K., Kormunda M., Neuwirthová L.:“Photoactive and non-hazardous kaolin/ZnO composites prepared by
calcination of sodium zinc carbonate“, Applied Clay Science 143 (2017) 345-353