Iron Oxide-Chitosan-Based Nanocomposite for Efficient Fluoride Removal From Drinking Water

The current study focuses on synthesizing and characterizing iron oxide-based nanoparticles (D-Fe₃O₄-NPs) using leave extract of Duranta erecta and iron oxide-chitosan-based nanocomposites (D-Fe₃O₄-NC). After successfully fabricating D-Fe₃O₄-NC, it is used for the adsorptive removal of fluoride ions (F⁻) from water. The characterization study indicated that rough, porous, crystalline, and nanostructure, along with various functional groups of the chitosan, which entrapped the D-Fe₃O₄-NPs in D-Fe₃O₄-NC and proved its possibility to be effective adsorbents for the quantitative elimination of F⁻ ions. The batch experimental adsorption study indicated that the quantitative removal of F⁻ was achieved at pH (7), initial concentration of metal ions (10 mg L⁻¹), the content of D-Fe₃O₄-NC (50 mg), contact time (30 min), and temperature (30 °C). The D-Fe₃O₄-NC provided 8.82 mM g⁻¹ quantitative F⁻ adsorption capacity. The D-Fe₃O₄-NC demonstrated a remarkable following the pseudo-second-order kinetics for successfully removing F⁻ through a monolayer adsorption process following the Langmuir isotherms model. The findings of the thermodynamic study revealed that the D-Fe₃O₄-NC followed the exothermic and spontaneous adsorption process for the adsorption of F⁻. Furthermore, D-Fe₃O₄-NC can easily be used several times after washing with diluted HNO₃ for the adsorptive removal of F⁻. Moreover, the F⁻ is quantitatively adsorbed (> 90%) from the collected drinking water samples.