Magnetic Chitosan Functionalized With a Zirconium‐Based Metal–Organic Framework for Enhanced Adsorptive Removal of Cr ( VI ) and Methyl Orange

ABSTRACT Toxic metal ions and dye pollutants cause serious threats to the ecological system, which requires urgent solutions for environmental remediation. In this study, a novel modified magnetic chitosan composite adsorbent was synthesized by integrating chitosan with the UiO‐66NH2 MOF and Fe 3 O 4 for the removal of Cr (VI) and MO from aqueous media. Several techniques were employed to characterize the surface area, functional groups, thermal stability, crystallinity, and surface chemical state of the adsorbent material. The impact of pH, adsorbate concentration, contact time, and temperature on adsorption performance were investigated. The results showed that the adsorbent material achieved equilibrium within 30 min for both the pollutants with an equilibrium adsorption capacity of 149.25 mg/g for MO and 169.49 mg/g for Cr (VI) at pH 3 and 5 respectively. The equilibrium data closely matched with the Langmuir model, signifying the chemical interactive behavior with the pollutants and the adsorbent surface. Kinetic analysis demonstrated that the experimental data showed good agreement with the pseudo‐second order model. Thermodynamic analysis revealed the adsorption phenomenon was spontaneous and endothermic in nature, while an exothermic nature was observed for MO. Furthermore, the composite retained a removal efficiency of more than 70% for both pollutants even after four consecutive cycles.