Majid Mohammadi - Department of Energy Engineering, Faculty of Science, Qom University of Technology, Qom, Iran.
Mehdi Sedighi - Department of Chemical Engineering, University of Qom, Qom, Iran.
Vahid Alimohammadi - oung Researchers and Elite Club, Arak Branch, Islamic Azad University, Arak, Iran.

In this study, the use of TiO۲/SiO۲ nanocomposites investigated to remove nitrate and total ironfrom 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 ۸۰%TiO۲ : ۲۰%SiO۲ 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 ironfrom wastewater withthe nanocomposite. The maximum removal of nitrate and total ironobtained with ۹۲.۸۴% and ۹۴.۳۲%, respectively. In addition, the optimum conditions for the maximum removal of nitrate and total iron together were estimated at pH= ۶.۸۱ and D/C= ۴۰.۸۴. Langmuir and Freundlich isotherm models evaluated, and Freundlich isotherm described the equilibrium adsorption data well.

Freundlich, Nitrate, Removal, RSM, Total iron, TiO۲/SiO۲ nanocomposites