Sahar Yazarloo - Department of chemistry, Faculty of Sciences, Sari Branch, Payam Nour University, Sari, Iran.
Taymaz Tabari - Department of Chemistry, Faculty of Sciences, Gorgan Branch, Islamic Azad University, Gorgan, Iran
Elham Tazikeh Lameski - Department of Chemistry, Faculty of Sciences, Gorgan Branch, Islamic Azad University, Gorgan, Iran
Rammin Zafar - Department of Chemistry, Faculty of Sciences, Gorgan Branch, Islamic Azad University, Gorgan, Iran

In this paper, we used multi-wall carbon nano-tube (MWNT) as an efficient adsorbent for removing of Congo red (CR) organic dye. The MWNT showed the excellent adsorption properties towards CR. The adsorption studies were carried out at different pH values, various adsorbent dosages and contact time in a batch experiments. The kinetic studies indicate that the removal process obeys the pseudo-second-order kinetic equation. Also, the isotherm evaluations reveal that the adsorption of CR by the MWNT follows the Langmuir model. Moreover, this paper discusses various thermodynamic parameters such as Gibbs free energy change (ΔG0), heat of adsorption (ΔH0) and entropy change (ΔS0).

Dye Removal; Chemical Absorption; Pseudo Second Order; Carbon Nano-tube