Inappropriate disposal of pollutants, such as heavy metal ions, dyes, pharmaceutical wastes, pesticides, and organic compounds into aquatic environments, is a significant environmental concern involving the world [1]. Dyes are mutagenic, carcinogenic molecules that are used as basic chemicals in various industries including leather, paper, textile, plastics, rubber, pharmaceutical, and cosmetics [1]. Discharge of dye wastewater into water bodies can increase the level of water pollution and block the sunlight and thereby can severely damage the ecological balance [2]. Cationic and anionic dyes are toxic due to the aromatic rings in their structure. The degradation of these dyes can induce diseases such as dizziness, jaundice, cyanosis, burns, allergy, vomiting, diarrhea, etc. [2]. Thus, it is essential to eliminate these pollutants. With the advancement of technology, novel methods have been introduced for water treatment; these methods are classified into three groups chemical, physical, and biological. Chemical approaches include oxidation, ion exchange, and precipitation; physical approaches include filtration, adsorption, air flotation, flocculation, and sedimentation; and biological approaches include biological aerobic and anaerobic methods [2]. In general, adsorption is the most appropriate and most effective method for water treatment due to its cost-effectiveness and high efficiency [2, 3]. Various compounds have been used as adsorbents, such as carbon nanotubes [4], activated carbon [5], zeolite [6], metal oxides [7], chitosan [8], core-shell nanoparticles, magnetic nanocomposites [10], silica [11], and double-layered [12]. Activated carbon is a widely used adsorbent because it is environmentally friendly and has a porous structure and high chemical stability. However, dispersion during the adsorption process is one of the main problems of activated carbon. Chitosan is a natural polymeric adsorbent and a suitable option for the adsorption of dyes due to the presence of hydroxyl and amine groups in its long polymeric chains [13]. Production of the activated carbon/chitosan composite can resolve the problem of dispersion of activated carbon in water and hence improve the adsorption process. Then, by synthesizing activated carbon/chitosan magnetic biocomposites, conditions for easy separation after adsorption can be improved. Accordingly, ferrites are extensively used as the magnetic component of the composite. For example, Malakootian et al. (2018) used the ferrite cobalt/activated carbon@chitosan for the elimination of ciprofloxacin. In this study, we synthesized the new nanoadsorbent of ferrite nickel-cobalt/activated carbon@chitosan through the coprecipitation method and analyzed the properties of this nanoparticle through FT-IR, BET, FESEM, XRD, and VSM. The methylene blue adsorption test was also performed to evaluate the effect of time through UV-Vis.