Batch and Fixed-Bed Study for Basic Blue 9 Separations using Synthetic Activated Carbon

Abstract

A local olive stone is a low cost and promising industrial waste with cellulose-lignin polymeric structure. The stones were dried, crushed, impregnated with phosphoric acid, and carbonized at 673 K for 3 h and used for the removal of basic blue dye (BB9) under different conditions. Equilibrium isotherms and different adsorption models, Langmuir and Freundlich, have been investigated. Different kinetic models have been studied in terms of pseudo first order and pseudo second order rate constants. In addition, the thermodynamic parameters have been calculated. The obtained results showed that the activated carbon has high adsorption capacity of BB9 and the adsorption process was found to increase on increasing temperature and pH. The Langmuir isotherm was better fitted for the experimental data. Moreover, the process involves pseudo second order kinetics and values of the change in entropy and heat of adsorption for BB9 adsorption on activated carbon were positive suggesting the adsorption process to be endothermic. The high negative value of change in Gibbs free energy indicates the feasible and spontaneous adsorption of BB9 dyes. The highest uptake capacity was obtained when a 4 cm bed depth was used at an inlet concentration of 80 mg L −1 and a flow rate of 4 cm 3 min −1 .