Optimization of fluoride adsorption onto a sonochemically synthesized nano-MgO/γ-Al2O3 composite adsorbent through applying the L16 Taguchi orthogonal design

Here in this work an effort has been made to in situ dope -Al2O3 as substrate with MgO nanoparticles through applying wet impregnation followed by sonochemical synthesis methods. The as-synthesized alumina supported nano-magnesia particles (4-30nm) were evaluated as a new defluoridating agent upon operating conditions such as pH, initial concentration, contact time, temperature and sorbent dose. The L-16 Taguchi statistical approach was implemented to optimize these operating conditions. The adsorbents were also characterized using the Fourier transform infrared spectroscopy, high resolution scanning electron microscope, X-ray diffraction and X-ray analysis methods. Under optimum conditions of pH 6.00 +/- 0.30, initial concentration of 0.05kg/m(3), dose of 0.70kg/m(3), contact time of 8400s and temperature of 298K, the fluoride removal efficiency was up to 97%. Results of the ANOVA revealed that the most influential factor on the removal efficiency of nanoadsorbent would be the initial concentration of F- ions followed by solution pH with 31 and 22% contribution, respectively. Moreover, contribution of experimental errors (noise factor) which is actually insignificant (0.06%) and F-ratios confirms the accuracy of the obtained results.