Removal of Reactive Orange 107 Dye from Aqueous Solution by Activated Carbon from Pinus elliottii Sawdust: a Response Surface Methodology Study

Adsorption of Reactive Orange 107 dye from aqueous solution was investigated using an activated carbon from Pinus elliottii sawdust chemically prepared with ZnCl2. The optimum conditions for the adsorption of Reactive Orange 107 dye by the activated carbon, obtained by response surface methodology, were pH = 10, ionic strength = 0.4 mol L-1, agitation rate = 200 rpm, and adsorbent dosage = 0.025 g. For the experimental data of the adsorption equilibrium, nonlinear models, i.e., the Langmuir, Freundlich, Dubinin-Radushkevich, and Temkin isotherms, were applied; the best correlation was found for the Langmuir model. The thermodynamic parameters were determined using the adsorption equilibrium constant of the Langmuir isotherm and the van 't Hoff equation. The parameters suggest an endothermic, Delta H degrees(ads) = 16.97 kJ mol(-1), and spontaneous process, Delta G degrees(ads) = -23.96, -25.23, -26.78, and -28.05 kJ mol(-1), at 298, 308, 318, and 328 K, respectively. The results indicate that the activated carbon was efficient for the adsorption of Reactive Orange 107 and has excellent potential for the treatment of colored effluents.