Photoactive and non-hazardous kaolin/ZnO composites prepared by calcination of sodium zinc carbonate

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 KICAF. Precursor sodium zinc carbonate Na2Zn3(CO3)(4).center dot 3H2O is formed and after its thermal decomposition the nanostructured ZnO is formed. Using this procedure the kaolin/ZnO composites containing similar to 6 and similar to 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 degrees 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 degrees C exhibits the highest photocatalytic activity. Leaching tests proved that the composites can be considered non-azardous.