Adsorption Isotherms of Oleic Acid on Carbon Nanotube

Abstract

The purpose of this research is to study the adsorption behaviour of oleic acid on the multi-wall carbon nanotube as a function of temperature and initial concentration of adsorbate through adsorption isotherms and evaluating the thermodynamic parameters (DG, DS and DH). The amount of oleic acid adsorbed on carbon nanotube surface increased with the concentration at constant temperature and decreased with the increase of temperature at constant concentration. The amount of oleic acid adsorbed nanotube surface was related to the concentration of adsorbate and temperature of the solution. The decrease in the values of DG with the increase of temperature demonstrated that the adsorption was supported by the high temperature and the positive value of DS showed that the oleic acid in a more randomic condition in the adsorbed state than in solution. The experimental results obtained at 295, 300 and 305 K showed that experimental data were well represented by the Langmuir, Freundlich and Temkin isotherms models.