Adsorption of Rhodamine B Dye from Aqueous Solution with Modified Active Carbon Made from Pine Cone

Abstract

In this study, active carbon obtained by pyrolysis of pine cone was used as an adsorbent in the removal of Rhodamine B dye from aqueous solutions. The produced active carbon was modified with 4 different chemical catalysts (ZnCl2, H3PO4, H2SO4 ve KOH) and the effect of the activation process on the adsorption efficiency was investigated. Adsorption experiments were studied in a batch system and the effects of parameters such as initial dye concentration, contact time, pH and temperature on the adsorption process were investigated. Maximum dye removal was observed at pH=3.0. Rhodamine B adsorption decreased with increasing initial dye concentration. With increasing contact time, the removal efficiency of Rhodamine B increased and equilibrium was reached in about 30 minutes. The highest dye removal efficiency (49.71%) was obtained as a result of activation of activated carbon with KOH. Experimental results were examined in terms of their suitability to the Langmuir and Freundlich isotherm models. According to the correlation coefficients, the Langmuir isotherm model was found to be more suitable for the experimental data obtained in this study. The adsorption mechanism has been explained with the thermodynamic parameters calculated. Accordingly, the obtained positive Delta G values showed that the adsorption process was not spontaneous, and the positive Delta H and Delta S values showed that the adsorption process was endothermic and random.