The investigation of adsorption of reactive blue dye onto organo-clay

THE INVESTIGATION OF ADSORPTION OF REACTIVE BLUE DYE ONTOORGANO-CLAYÇiğdem ÖmeroğluDepartment of Chemistry, Master Thesis, 2007Thesis Supervisor: Prof. Dr. Yunus ErdoğanSUMMARYIn this study, the utilization of modified bentonite with a cationic surfactant(dodecyltrimethylammonium (DTMA) bromide) as an adsorbent was investigated to remove asynthetic textile dye (Reactive Blue 19 (RB19)) by adsorption from aqueous solutions. Thevarious experimental parameters such as pH, contact time and temperature were examined forthe adsorption of RB19 onto DTMA-bentonite. The modification of bentonite with a surfactantwas examined using the elemental analysis and FTIR spectroscopic technique. Effective pH forthe was around 1.5. The first-order and pseudo-second-order adsorption kinetic models; theLangmuir and Freundlich adsorption isotherm models were applied to the experimental data inorder to describe the kinetics and isotherm data of the adsorption. The pseudo-second-order rateequation was able to provide the best description of adsorption kinetics for the adsorption ofRB19 onto DTMA-bentonite. The validity of kinetic models can be quantitatively checked byusing a normalized standard deviation ∆q (%) and the results show that the values of ∆q (%) forthe best-fitted model, which is the pseudo-second-order model, are less than 1.952%. TheLangmuir isotherm model was found to be the best to represent the equilibrium withexperimental data. The maximum adsorption capacity (qmax) has been obtained to be 3.30x10−4mol g−1 or 206.58 mg g−1. The thermodynamic study indicated that the adsorption of RB19 ontoDTMA-bentonite was favored with the negative Gibbs free energy values.Adsorption, Bentonite, Isotherms, Kinetics, Organoclay, Reactive dye, Validity,Keywords:Thermodynamics