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

In this work, ZrO 2 –TiO 2 heterojunction photocatalysts were successfully synthesized using sol–gel method. The effect of ZrO 2 doped into TiO 2 on the retardation of the electron–hole pairs were investigated. The crystalline structure of ZrO 2 –TiO 2 heterojunction photocatalysts was verified through x–ray diffraction (XRD) patterns and the crystallite size were found smaller compared to TiO 2 and ZrO 2 photocatalysts. Morphological characterization evidenced that the co–doping of ZrO 2 into TiO 2 has altered the particle size of TiO 2 and the shape of the synthesized particle through chemical nucleation and growth process in bulk solution. The small crystallite size of the ZrO 2 –TiO 2 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 ZrO 2 –TiO 2 heterojunction photocatalysts on oily wastewater as model pollutant enhanced with the incorporation of small amount of ZrO 2 compared to TiO 2 . The presence of surface adsorbed water peaks and hydroxyl groups as disclosed by Fourier transform infrared (FTIR) supported the finding of the study.