Removal of tartrazine by activated carbon biosorbents of Lantana camara: Kinetics, equilibrium modeling and spectroscopic analysis

Preparation of the activated carbon biosorbents from Lantana camara weed by sulphuric acid activation was carried out. Laboratory prepared activated carbon was used as adsorbents for the removal of an acidic dye tartrazine from aqueous solutions. Liquid-phase adsorption experiments were conducted and the maximum adsorption capacity of activated carbon was determined. The effects of various process parameters, i.e., temperature, pH, initial tartrazine concentration, contact time on the adsorption capacity of activated carbon were investigated. The kinetic models for tartrazine adsorption onto activated carbon were studied. Freundlich isotherm (K-F, 98.401 Lg(-1)) showed better fit than Langmuir isotherm (Q(0), 90.900mg g(-1)) for the activated carbon. The rates of adsorption were found to confirm the pseudo-second-order kinetics with good correlation. The separation factor (R-L) revealed the favorable nature of the isotherm of the tartrazine-activated carbon system. The values of activation parameters such as free energy (Delta G degrees, -10.346 to -10.983 kJ mol(-1)), enthalpy (Delta H degrees, 22.976 kJ mol(-1)) and entropy (Delta S degrees, 154. 555 J mol(-1) k(-1)) were determined, respectively, indicating that the adsorption was spontaneous, endothermic and favorable process in nature. a 2014 Elsevier Ltd. All rights reserved.