Iron(II) cross-linked chitin-based gel beads: Preparation, magnetic property and adsorption of methyl orange

Chitin/alginate magnetic nano-gel beads (MCAs) were successfully prepared from 8 wt.% NaOH/4 wt.% urea aqueous solution by ionic cross-linking. Their structure and properties were investigated using scanning electron microscopy, X-ray diffraction, and vibrating sample magnetometry. The results showed that the magnetic iron oxide nanoparticles synthesized in situ with a mean diameter of 30 nm were uniformly dispersed and immobilized in the chitin/alginate matrix. The structure and nature of iron oxide were conserved perfectly, and the MCAs had extremely small hysteresis loop and low coercivity. Moreover, MCAs could efficiently adsorb the methyl orange from wastewater. The iron oxide nanoparticles in the MCAs played an important role in both the creation of the magnetic-induced transference and the improvement of the adsorption capacity. This work provides a novel, low-cost, simple, and “green” process for synthesizing the chitin-based magnetic nanocomposite gel beads, which had potential application on the removal of hazardous materials.