Background & objectives: Discharge of dye containing effluent into water resources can pose hazardous effects to the environment and human health because of their carcinogenic, mutagenic, and toxic nature. The present research was performed to study the efficiency of cobalt ferrite magnetic nanoparticles and its modified type in removing Direct Red 23 from aqueous solutions.

Methods: In this applicable study magnetic nanoparticle of cobalt ferrite and modified cobalt ferrite were synthesized. Direct Red 23 dye was selected as a model to evaluate decolorization potential of the adsorbent. The effects of parameters such as initial dye concentrations (50-200 mg/L), adsorbent dose (0.1-0.4 g/L), pH (2-10) and the effect of inorganic salts (NaCl, Na₂SO₄, NaHCO₃ and Na₂CO₃) on the adsorption process were also studied. Longmuir, Freundlich, and Tempkin isotherm models were applied for data evaluation.

Results: Maximum efficiencies of cobalt ferrite magnetic nanoparticles and modified cobalt ferrite magnetic nanoparticles for dye removal were 14.45 and 81%, respectively. The maximum adsorption capacity of modified cobalt ferrite magnetic nanoparticles for Direct Red 23 was 188.6792 mg/g of adsorbent. Adsorption of dye on modified adsorbent followed Langmuir isotherm.

Conclusion: Based on the obtained results, it is concluded that modified cobalt ferrite magnetic nanoparticles can be used as an effective adsorbent for removal of Direct Red 23 form colored effluents.