Photocatalytic removal of olive mill waste water by TiO2 loaded on sepiolite and under natural solar irradiation



The photocatalytic removal of color, lignin, and phenol from olive mill waste water (OMW) has been investigated by using TiO2/Sepiolite nanoparticle. TiO2 particles were immobilized by using a titanium solution and sepiolite by the wet impregnation method. Nanocrystalline TiO2 anatase phase on sepiolite was obtained using an adequate thermal treatment of 500°C for 2 h considering thermal instability of the sepiolite. TiO2/Sepiolite material was characterized by scanning electron microscopy with energy dispersive X-ray microanalyses and Brunauer-Emmett-Teller surface area measurements. Then, the photocatalytic experiments have been done under solar irradiation and the different variables (TiO2/Sep. dose, solution pH, oxidant concentration and reaction times) and the degradation rations were found to be strongly influenced by all investigated parameters. The photocatalytic degradation of color, lignin, and phenol was favorable at pH 9–11.0. Optimum values of catalyst dose and oxidant concentration were found to be 0.8 g L−1 and 16 mL L−1, respectively. In addition, the pseudo-first order model was applied and r2 values were noted from 0.92 to 0.99. It can be said that this study proves the effectiveness of photocatalytic removal for highly concentrated organic pollutants in OMW. © 2010 American Institute of Chemical Engineers Environ Prog, 2011