Removal of Pb(Ⅱ) and Cd(Ⅱ) by MnFe_2O_4@SiO_2@VTMS Nanocomposite Hydrogel from Aqueous Solutions

摘要

Lead and Cadmium, identified as toxic heavy metals, can cause a significant imbalance in the ecosystem due to their tendency to bioaccumulate. These metals can be seriously harmful to human health and the environment. In this work, a magnetic nanocomposite hydrogel was produced via grafting copolymerization of acrylic acid (AA) and acrylamide (AAm) in the presence of MnFe_2O_4@SiO_2@ Vinyltrimethylsilane (VTMS) as a cross-linking agent. To effectively adsorb Pb(Ⅱ) and Cd(Ⅱ) from an aqueous solution, the prepared magnetic nanocomposite hydrogel was applied. XRD, VSM, FT-IR, SEM-EDS, and TEM methods validated the structure of the prepared nanocomposite hydrogel. In addition, thermal characteristics was evaluated by TGA. The features that influence the adsorption of Pb(Ⅱ) and Cd(Ⅱ) ions include pH, contact time, initial concentration of ions and dose of adsorbent experimented. The adsorption isotherm was investigated at various temperatures by employing Langmuir, Freundlich, Redlich-Peterson and Temkin. The adsorption data best fitted The Redlich-Peterson isotherm model. The adsorption kinetics models such as intraparticle, pseudo-first-order, pseudo-second-order and elovich in metal ion solutions of 25, 50, 100, and 150 mg/L were studied. The pseudo-first-order model well explained the adsorption results. The maximal adsorption capacities of magnetic nanocomposite hydrogel forPb(Ⅱ) and Cd(Ⅱ) elimination from a 150 mg/L metal solution were 131 and 126 mg/g, respectively. The adsorption was employed effectively for four cycles of adsorption and desorption. Therefore, the nanocomposite hydrogel examined in this work may be used for various water filtration purposes, notably for eliminating toxic metals.