The Cystoseria myricaas algae collected from Persian Gulf was dried and applied as a substrate for nanocellulose extraction. The Fe3O4, Fe3O4@SiO2, Fe3O4@SiO2-NH2-GO, and Fe3O4@SiO2-NH2-GO-NC are synthesized. The synthesized compounds are characterized by x-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) method and vibrating sample magnetometer (VSM). Additional characterization, including scanning electron microscopy (SEM) and energy dispersed X-ray spectroscopy (EDX) was performed for the ultimate product. Both isotherm and kinetic modeling are investigated for all synthesized compounds as adsorbents. The ΔG0 is measured in five different temperatures and four different pH. The Hg (II) removal is predicted by the RSM model.