Modeling and optimization of Nitrate and total Iron removal from wastewater by TiO2/SiO2 nanocomposites

In this study, the use of TiO2/SiO2 nanocomposites investigated to remove nitrate and total iron from wastewater. The nanoparticles and nanocomposites were characterized by the Brunauer, Emmett, and Teller (BET), Field Emission Scanning electron microscopy (FESEM), Fourier transform infrared (FTIR), X-ray diffraction (XRD) and X-ray fluorescence (XRF). According to the BET results, the nanocomposite with 80%TiO2 : 20%SiO2 considered an adsorbent for the treatment of water. In this work, the application of the Response Surface Methodology (RSM) was presented to optimize various parameters, including the D/C (mg adsorbent /(mg/L) initial) and the initial pH for removal of nitrate and total iron from wastewater with the nanocomposite. The maximum removal of nitrate and total iron obtained with 92.84% and 94.32%, respectively. In addition, the optimum conditions for the maximum removal of nitrate and total iron together were estimated at pH= 6.81 and D/C= 40.84. Langmuir and Freundlich isotherm models evaluated, and Freundlich isotherm described the equilibrium adsorption data well.