Enhanced Performance of Chitosan via a Novel Quaternary Magnetic Nanocomposite Chitosan/Grafted Halloysitenanotubes@ZnγFeO for Uptake of Cr (III), Fe (III), and Mn (II) from Wastewater.

A novel chitosan/grafted halloysitenanotubes@Znγmagnetite quaternary nanocomposite (Ch/g-HNTs@ZnγM) was fabricated using the chemical co-precipitation method to remove the ions of Cr (III), Fe (III), and Mn (II) from wastewater. The characteristics of the synthesized Ch/g-HNTs@ZnγM quaternary nanocomposite were investigated using FTIR, SEM, XRD, GPC, TGA, TEM, and surface zeta potential. The characterization analysis proved that the mentioned nanocomposite structure contains multiple functional groups with variable efficiencies. Additionally, they proved the existence of magnetic iron in the nanocomposite internal structure with the clarity of presentation of gaps and holes of high electron density on its surface. The results showed that the pH and time to reach an equilibrium system for all the studied metal ions were obtained at 9.0 and 60 min, respectively. The synthesized Ch/g-HNTs@ZnγM nanocomposite exhibited maximum adsorption removal of 95.2%, 99.06%, and 87.1% for Cr (III), Fe (III), and Mn (II) ions, respectively. The pseudo-second-order kinetic model and, for isotherm, the Langmuir model were best fitted with the experimental data. The thermodynamic parameters indicated the exothermic and spontaneous nature of the adsorption reaction as proven by the ΔH° and ΔG° values. Additionally, chemical adsorption by the coordination bond is supposed as the main mechanism of adsorption of the mentioned metal ions on the nanocomposite. Finally, Ch/g-HNTs@ZnγM displays prospected advantages, such as a low-expense adsorbent, high efficiency and availability, and an eco-friendly source, that will reduce the environmental load via an environmentally friendly method.