Application of Surfactant for Enhancing the Adsorption of Azo Dye Onto Buckthorn Tree Wood Surface

Abstract

Cetyl trimethyl ammonium bromide (CTAB), was used as surfactant to enhance the removal of Congo- red (C-R) dye from its solution by employing a wood of buckthorn tree as a low cost and eco-friendly adsorbent. Different factors affecting the sorption process like, time of adsorption, wood dose, initial (C-R) concentration and hydrogen ion concentration have been studied for both adsorbent wood (W) and modified wood (MW). The suitability of the two isotherm models Langmuir and frundlich to the equilibrium results was mentioned for the adsorption of (C-R) on both wood and modified wood. From the value of correlation - factor, frundlich model give a better fit than Langmuir isotherm model. Thermodynamic function such as the changes in enthalpy ∆H°, entropy ∆So and Gibes free energy ∆Go for the adsorption process was guessed. These values illustrate that physi-sorption take place .The negative values of ∆Ho shows that the adsorption process accompany with heat releasing with decreasing the randomness of the (solid-solution) interface. Furthermore the negative values of ∆G° indicated that adsorption of (C-R) dye onto the wood and modified wood occurs spontaneously.