Removal of Heavy Metals: Pb(II), Ni(II) And Cd(II) By Fe3O4@SiO2-TMPDT Adsorbent Prepared From Rice Husk Ash

<p>The adsorption of Pb(II), Ni(II), and Cd(II) metal ions onto Fe<sub>3</sub>O<sub>4</sub>@SiO<sub>2</sub>-TMPDT adsorbent was carried out through batch experiments. In this study, Fe<sub>3</sub>O<sub>4</sub>@SiO<sub>2</sub>-TMPDT adsorbent was synthesized through a sol-gel process using sodium silicate extracted from rice husk ash (Na<sub>2</sub>SiO<sub>3</sub>)<sub>RHA</sub> with the addition of magnetite (Fe<sub>3</sub>O<sub>4</sub>) and modifier N<sup>1</sup>-(3-trimethoxysilylpropyl) diethylenetriamine (TMPDT). The synthesized adsorbent was then characterized by FTIR. The Fe<sub>3</sub>O<sub>4</sub>@SiO<sub>2</sub>-TMPDT adsorbent was prepared with suspension Fe<sub>3</sub>O<sub>4</sub>:(Na<sub>2</sub>SiO<sub>3</sub>)<sub>RHA</sub> ratios (v/v) of 1:4, 2:3, and 1:1, and varying the amounts of TMPDT of 1; 2.5 and 5 mL. The optimum pH to perform conditions adsorption for Pb(II) metal ions was determined to be 4, while Ni(II) and Cd(II) were 5. In addition, the adsorption process followed a pseudo-second-order kinetic model, and the adsorption isotherm was consistent with the Langmuir isotherm. The adsorption capacities for Pb(II), Ni(II), and Cd(II) were 11.760 mg/g, 1.864 mg/g, and 1.888 mg/g, respectively.</p>