Synthesis of Chitosan-Natrolite modified magnetite nanocomposite (Chio/Fe3O4@NAT) for photocatalytic degradation of methyl orange using response surface model (RSM)

The present study focuses on the synthesis of Chito/Fe₃O₄@NAT nanocomposite for the photocatalytic degradation of methyl orange (MO) from aqueous solutions. The synthesized nanocomposites were characterized using Ultraviolet-Visible spectrophotometer(UV-Vis), Scanning electron microscope (SEM), X-Ray diffraction spectroscopy (XRD), and Fourier transform infrared spectroscopy (FT-IR) for the optical, morphological, particle size, and surface functional group study. The UV-Vis spectra revealed a peak at 285 nm for (1:1:1) Chito/Fe₃O₄@NAT. The XRD pattern confirmed the crystalline size of 19.59 nm, further confirmed by SEM, having a heterogeneous and porous surface morphology. FT-IR spectra showed the presence of bioactive molecules and a peak at 557 cm^−1, confirming the presence of Fe-O stretching vibration. Furthermore, the photocatalytic degradation efficiency of Chito/Fe₃O₄@NAT of the nanocomposite on MO dye was investigated under dark, ultraviolet lamp (254 nm), and sunlight conditions. The effects of three independent parameters such as irradiation time (30-90) min, catalyst dose (0.01- 0.05) g, and initial dye concentration (10-30) mg/L were examined and optimized by Box-Behnken design (BBD). The optimal conditions of a catalyst dose of 0.0596 g, an initial concentration of dyes of 30 mg/L, and an irradiation time of 90 min. The experimental data of degradation followed a Hinshelwood-pseudo-first-order kinetic model (R² = 0.997) while the equilibrium degradation data showed that the Langmuir isotherm (R² = 0.9962). The synthesized nanocomposite exhibited excellent stability and recyclability, maintaining 60 % dye degradation capacity even after 6 cycles.