Microwave‐Assisted Synthesis of Chitosan–Iron Oxide (CS@Fe ₃ O ₄ ) Nanocomposite for Removal of Cationic and Anionic Dyes

ABSTRACT The present study investigates the microwave‐assisted synthesis of a Chitosan‐Iron Oxide (CS@Fe 3 O 4 ) nanocomposite for the removal of Alizarine Red (AR) and Malachite Green (MG) dyes. The synthesized materials were characterized by XRD, FTIR, SEM, TEM, and pHZPC to evaluate their elemental compositions, functional groups, surface structures, and surface charge. The AR and MG dye removal experiments were conducted using a UV–vis spectrophotometer at 432 and 617 nm wavelength, respectively, under various conditions including concentration (20–100 mg L −1 ), contact time (0– 120 min for AR and 0–60 for MG), dose (0.4–2 g L −1 ), pH (2–12). The maximum removals of 91% & 96% obtained at 2 and 10 pH, 5 and 100 mg L −1 concentration, 1 & 2 g L −1 dose of CS@Fe 3 O 4 for AR & MG dyes, respectively. Adsorption kinetics were determined to be pseudo‐second order for both linear and non‐linear regression. The Langmuir adsorption capacity was 82.29 and 46.73 mg g −1 for AR and MG dyes, respectively. The thermodynamic parameters observed a spontaneous and endothermic. The field applicability of the adsorbent was confirmed through ionic strength, regeneration capacity, rapid and low‐cost synthesis, with potential applicability in wastewater treatment.