The objective of this investigation was to prepare magnetic bionanocomposite adsorbents based on κ-carrageenan using a simple and efficient method. The magnetic κ-carrageenan was prepared through in situ method and was crosslinked by chitosan polysaccharide through electrostatic attractions. The magnetic bionanocomposites were assessed as adsorbents to remove methylene blue (MB) from its aqueous solution. The effects of preparation conditions and operational terms including contact time, dye concentration, ion strength, pH, and temperature on removal of MB were investigated. The experimental adsorption isotherms of bionanocomposites for MB were described well by Langmuir model. According to the Langmuir constant (qm), the maximum adsorption capacities of non-magnetic and magnetic adsorbents for MB were obtained 130.4 and 123.1 mg g−1, respectively. Desorption experiments indicated that regeneration of the adsorbents can be made by using KCl solution in water/ethanol mixture. According to the data of the present work, it can be concluded that the magnetic κ-carrageenan bionanocomposites can be considered as an eco-friendly adsorbent for removal of cationic dye from aqueous solutions.
