Simultaneous oily wastewater adsorption and photodegradation by ZrO2–TiO2 heterojunction photocatalysts

In this work, ZrO2–TiO2 heterojunction photocatalysts were successfully synthesized using sol–gel method. The effect of ZrO2 doped into TiO2 on the retardation of the electron–hole pairs were investigated. The crystalline structure of ZrO2–TiO2 heterojunction photocatalysts was verified through x–ray diffraction (XRD) patterns and the crystallite size were found smaller compared to TiO2 and ZrO2 photocatalysts. Morphological characterization evidenced that the co–doping of ZrO2 into TiO2 has altered the particle size of TiO2 and the shape of the synthesized particle through chemical nucleation and growth process in bulk solution. The small crystallite size of the ZrO2–TiO2 heterojunction recorded the highest surface area with higher incident in the mesopores volume as confirmed by Brunauer–Emmett–Teller (BET) analysis. The adsorption–photodegradation performance of the ZrO2–TiO2 heterojunction photocatalysts on oily wastewater as model pollutant enhanced with the incorporation of small amount of ZrO2 compared to TiO2. The presence of surface adsorbed water peaks and hydroxyl groups as disclosed by Fourier transform infrared (FTIR) supported the finding of the study.