Low-Cost Magnetic Fe₃O₄/Chitosan Nanocomposites for Adsorptive Removal of Carcinogenic Diazo Dye

Abstract—: The eco-friendly adsorptive removal of Congo red (CR) from aqueous medium using Fe₃O₄/chitosan nanocomposites was investigated. The nanocomposites were synthesized by using a cost effective reductive precipitation method. The structural characterization of nanocomposties was determined by field emission scanning electron microscopy, thermal gravimetric analysis, fourier transform infrared spectroscopy, and magnetic property measurement system. Successful coating of chitosan on the iron oxide nanoparticles was confirmed by field emission scanning electron microscopy. The synthesized nanocomposites showed a maximum adsorption capacity of 47 mg/g for CR from an aqueous solution. Based on non-linear regression, the Langmuir isotherm fitted the experimental data better than the Freundlich and Tempkin models. The separation factor (R_L) calculated from the Langmuir adsorption isotherm indicated that CR adsorption on the nanocomposites was favorable. The obtained Fe₃O₄/chitosan nanocomposite is a cost-effective adsorbent and can be easily retrieved from an aqueous solution by a magnet after decontamination of CR.