Anchored Chitosan-Functionalized Magnetite Nanoparticles for Crystal Violet Decolorization from Aqueous Samples

In this research, 3-(triethoxysilyl)propyl isocyanate (TESPIC) functionalized chitosan was successfully synthesized to fabricate silica-coated magnetite nanoparticles (Fe₃O₄@SiO₂-CS MNP_s).

The synthesized MNPs were characterized using XRD, FT-IR, SEM, and TEM instruments and were utilized for the decolorization of Crystal Violet cationic dye (CV). The affecting variables controlling CV removal efficiency were investigated using the Taguchi fractional factorial design method (L₁₆ array).

Under the optimized removal conditions (adsorbent amount = 0.12 g (4.8 g L-¹), pH = 4, ionic strength = 0.05 mol L-¹ NaCl, and 30 min stirring), 98.2% of the CV dye was eliminated. The kinetic and equilibrium adsorption isotherms were explained by the pseudo-second-order kinetic (R² = 0.999) and Freundlich isotherm models, respectively. MATLAB's fmincon function as an efficient solution was applied in order to compare the Redlich-Peterson three-parametric isotherm model with two-parametric models. Moreover, the Fe₃O₄@SiO₂-CS-TESPIC MNPs showed recyclability and reusability for subsequent runs.

The findings confirmed that these functional MNPs can be considered as proper adsorbents for the removal of CV dye from the aqueous solutions.