Schiff Base Polymer-Functionalized Fe₃O₄@SiO₂ Nanoparticles as an Efficient Adsorbent for Heavy Metal Removal

The objective of this work is to develop a magnetic nanoadsorbent with easy separability and high efficiency for the heavy metal removal from aqueous media. For this purpose, Fe₃O₄@SiO₂@PSA–Schiff base is synthesized and applied as an efficient adsorbent for the removal of Cd²⁺ and Zn²⁺ ions. In this respect, Fe₃O₄ nanoparticles are synthesized and coated with a silica shell using Stöber method. To tackle the issue of low selectivity of the core-shell nanoparticle, the nanoparticles is functionalized with a new linker and selective synthesized complexing agent of polysalicylaldehyde (PSA). The structure of the synthesized nanoadsorbent is characterized using FT-IR, XRD, TGA, TEM and FE-SEM analyses. The adsorption performance of this nanoadsorbent is evaluated by investigating the effects of key parameters of extraction. The maximum adsorption capacity of Zn²⁺ and Cd²⁺ are obtained 107.9 and 100.0 mg/g, respectively. Isotherm studies indicated that the adsorption process followed the Langmuir model suggesting the formation of a monolayer adsorption on the adsorbent surface. Kinetic studies revealed that the adsorption process is in agreement with the pseudo-second-order kinetic model. In conclusion, the synthesized magnetic nanoadsorbent is considered a promising candidate for the removal of heavy metal ions in water and wastewater treatment plant.