Magnetic poly-o-vanillin-functionalized core–shell nanomaterials as a smart sorbent for scavenging mercury(ii) from aqueous solution

Abstract

In the present work, a poly-o-vanillin-functionalized magnetic nanoparticle of PoVan/CoFe₂O₄@mSiO₂ with core–shell structure was synthesized through a facile, green and low cost method. The rapid removal of Hg(II) by the prepared nanocomposites was researched by batch adsorption experiments and the adsorption conditions were optimized with response surface methodology (RSM). The optimization of RSM shows that the as-prepared PoVan/CoFe₂O₄@mSiO₂ magnetic nanomaterial has a maximal adsorption capability of 263.6 mg g⁻¹ toward Hg(II) ions. The removal process of Hg(II) ions acts in accordance with Langmuir and pseudo-second-order kinetic models. The Dubinin-Radushkevich calculation indicates that the removal process is spontaneous and exothermic. In addition, the adsorption of Hg(II) ions onto PoVan/CoFe₂O₄@mSiO₂ is mainly completed through forming a stable complex by electrostatic attraction and chelation. The adsorption efficiency of the regenerated adsorbent is still high after five cycles. The used adsorbent of PoVan/CoFe₂O₄@mSiO₂ has good magnetic property and can easily be separated from aqueous solution. The results indicate that the magnetic nanomaterial PoVan/CoFe₂O₄@mSiO₂ could be a promising adsorbent to remediate mercury pollution from wastewater.