Adsorption of Basic Blue 41 Using Juniperus Excelsa: Isotherm, Kinetics and Thermodynamics Studies

Abstract

In this study Juniperus excelsa shavings powder (JESP) was utilized as an adsorbent for the removal of Basic Blue 41 (BB 41) which is one of the common basic dyes, from aqueous solution. The adsorption experiments were carried out in a batch system and effects of initial concentration of dye, interaction time and temperature were investigated. Langmuir, Freundlich and Temkin adsorption isotherms were used to model equilibrium data. According to the results, Freundlich isotherm model becomes more convenient option compared with Langmuir and Temkin models. Freundlich model coefficients are raise as the temperature rises, showing that the adsorption process becomes favorable higher temperature. The kinetic parameters were determined by pseudo first order (PFO), pseudo second order (PSO) and intra-particle diffusion (IPD) models. Results indicated that experimental and calculated qe values are matched to each other. Thus the process fits PSO kinetic model with higher R2 values than other two models. Kinetic constants become closer to both temperatures and initial concentrations and qe values are increases with increasing concentration of BB 41. Initial dye concentration elevates from 25 to 100 mg L-1, dye adsorption capacity onto JESP from 3.06 to 16.53 mg g-1, respectively. Thermodynamic parameters for instance free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) were assessed. Enthalpy and entropy of this separation process are determined from 3081.91 J mol-1 and 12.33 kJ mol-1, respectively. The negative values of ΔG° showed that this separation process was endothermic and natural. The research results demonstrate that JESP may be a substitute than pricey adsorbents for dye removal. © 2019 Yildiz Technical University. All rights reserved.