Adsorption of reactive dye on palm-oil industry waste: Equilibrium, kinetic and thermodynamic studies

摘要

The adsorption of C. I. Reactive Red 120 (RR120) on activated oil palm ash (AOPA) was studied in a batch system. The adsorption studies were carried out at different initial dye concentrations (50-600 mg L~(-1)), solution pH (2-12) and temperature (30,40 and 50°C). The experimental data were analyzed by the Langmuir and Freund-lich isotherms. The Freundlich model agreed very well with the experimental data. The maximum monolayer adsorption capacities obtained from the Langmuir model was 200.12, 334.78 and 376.41 mg g~(-1) at 30, 40 and 50°C, respectively. The pseudo-first-order and pseudo-second-order were used to describe the kinetics data. The adsorption kinetics of RR120 onto AOPA was described by the pseudo-second-order kinetic equation. The activation energy, change of Gibbs free energy, enthalpy and entropy of adsorption were also evaluated for the adsorption of RR120 onto AOPA.