Removal of Trace Amounts of Heavy Metals Using Silica Aerogel Nanocomposite with Ionic Liquid and Graphene Oxide: Optimization by Response Surface Methodology

Heavy metals are of the most dangerous and hazardous environmental contaminants for humans. In the present study, adsorption method, which is known as one of the most effective and economical methods to reduce pollution related to heavy metals, was used to simultaneously remove chromium (VI) and mercury from contaminated water. The adsorbent was synthesized by modifying magnetized graphene oxide with magnetic iron nano-oxide by tetrahydro- silane and 3-chloropropyl trimethoxy-silane. It was found that the highest amount of adsorption occurs at pH 6.5. In addition, by increasing the concentration of contaminants by up to 150 mg / l and also reducing the adsorbent dose to 0.5 g / l, the adsorbent capacity increased. Physical, chemical and morphological properties of the adsorbent were determined using EDS and FE-SEM analyses. Freundlich, Langmuir and Temkin, and Baghdadi (UT) isotherms were studied and the results showed that the adsorption process in both heavy metals follow the Langmuir model. The Langmuir isotherm was then plotted at different pH, with the highest adsorption capacity for mercury at pH 6.5 and 109 mg / g adsorbent and for chromium (VI) at 99 pH and 99 mg.