New magnetic hybrid materials were developed by the encapsulation of iron oxide nanoparticles into a chitosan matrix. A green synthesis method to obtain metallic nanoparticles was conducted using eucalyptus extract as reducing agent. Well-formed iron oxide nanoparticles were successfully synthesized. Under precise conditions, the encapsulation of the synthesized iron oxide nanoparticles in chitosan beads leads to the formation of magnetic hybrid organic/inorganic materials. The XRD pattern of these materials shows peaks that match with structure similar to maghemite for those materials showing magnetic properties. The new hybrid materials were proved as sorbent in a complete arsenic removal study (pH dependence, kinetic and equilibrium experiments) showing good features and sorption capacity. The large scale sorption capacity of the new material was also successfully proved in a continuous flow study using a column filled with beads of the hybrid magnetic material. (C) 2016 Elsevier B.V. All rights reserved.