Background & objectives: In present study modification of carbon nanotube in order to increase its absorption capacity to remove organic dyes from aqueous solutions in a batch system was investigated.

Methods: Carbon nanotube was modified by linear aliphatic polymers with amino groups. Its chemical properties were evaluated by Raman spectroscopy and Acid blue 1 (AB 1) dye was selected as a model. The effects of parameters on the adsorption process such as initial dye concentration, adsorbent dose, pH and the effect of inorganic salts were also studied. In order to understand the adsorption process, Longmuir and Freundlich isotherm models and pseudo first order and pseudo-second-order kinetic models were applied for data evaluation.

Results: Result showed that the adsorption equilibrium for AB 1 was best described by Langmuir (R²=0.99) and pseudo-second-order kinetic (R²=0.99) models. Results also showed that modified nanotube for dye concentration of 100 mg/l has a maximum adsorption capacity of 700 mg/g. The adsorbent had the maximum efficiency in pH=2. Adsorption percentage was increased with increasing adsorbent dose and decreased with increasing initial concentration of AB1. Adding mineral salts slightly decreased adsorption efficiency.

Conclusion: It is concluded that modified carbon nanotube can be used as an effective adsorbent for removal of dyes form colored effluents.