Adsorption properties of activated carbon fiber for highly effective removal of methyl orange dye

A commercial activated carbon fiber (ACF) was applied as efficient adsorbents for adsorption of methyl orange (MO) dye in aqueous solution. The surface morphology and surface area were characterized by scanning electron microscopy (SEM) and N-2 adsorption, respectively. The results showed that ACF had good adsorption capacity on MO dye due to the large surface area and excellent pore size structure. In addition, the adsorption property of MO dye in aqueous solution onto ACF was investigated as a function of the initial dye concentration, pH value and temperature of solution. It's observed that the adsorption capacity of ACF for MO dye increased with the increases in the initial dye concentration and the temperature of solution, but the pH value had no significant effect on ACF adsorption performance. Langmuir, Freundlich and Temkin isotherm models were employed to fit the equilibrium isotherm data, and the Langmuir model fitted the experimental data best implying the homogeneity of the adsorbent surface sites. Besides, thermodynamics parameters, Gibbs free energy Delta G(0), entropy Delta S-0 and enthalpy Delta H-0, were calculated, and the values indicated that the phisisorption process of MO dye onto ACF was spontaneous, endothermic and attractive.