Biosorption of dye from textile wastewater effluent onto alkali treated dried sunflower seed hull and design of a batch adsorber

Alkali treated dried sunflower seed hull (DSSH) was used as adsorbent for the decolorization of wastewater effluent from the textile industry. Batch adsorption studies were performed as a function of contact time, initial solution pH, initial dye concentration, adsorbent dosage and temperature. Kinetic analysis revealed that adsorption experimental data was best fitted by pseudo-second order model at all textile dye concentrations tested. Based on the pseudo-second order rate constants obtained using Arrhenius and Eyring equations, the activation parameters for the formation of activated complex between Textile dye molecules and dried sunflower seed hull were determined: namely the activation energy (8.79 kJ/mol), the change of entropy (-39.57 kJ/mol/K), enthalpy (8.79 kJ/mol), and Gibbs free energy (range 6.27-8.11 kJ/mol). The equilibrium adsorption data was found to follow the Langmuir isotherm model and maximum monolayer capacity was found to be 169.5 mg/g at 25 degrees C. The Langmuir isotherm model was applied to the design of a single-stage adsorber. From the thermodynamics analysis the magnitude of enthalpy change (Delta H) was found to be 8.79 kJ/mol; indicating that physical forces were involved in biosorption of dye onto DSSH. (C) 2015 Elsevier Ltd. All rights reserved.