Kinetics of Acid Blue 1 Adsorption from Aqueous Solution by Carbonaceous Substrate Produced from Biotic Precursor

Abstract

Adsorption of acid blue 1 from aqueous solution onto carbonaceous substrate produced from the wood of Paulownia tomentosa was investigated. The samples characterized by FTIR, SEM, EDS and XRD techniques, indicated that the surface functional groups like carboxyl, lactones or phenols and ethers have disappeared at high activation temperature (800 ℃) and as a result porous structure was developed that has a positive effect on the adsorption capacity. Bangham and parabolic diffusion models were applied to the kinetic adsorption data, which show that the adsorption of acid blue 1 was a diffusion controlled process. The reaction rate increased with the increase in temperatures of both the adsorption and activation. Thermodynamic parameters like ∆E ≠ , ∆H ≠ , ∆S ≠ and ∆G ≠ were calculated from the kinetic data. The negative values of ∆S ≠ reflected the decrease in the disorder of the system at the solid-solution interface during adsorption. Gibbs free energy (∆G ≠ ), representing the driving force for the affinity of dye for the carbon surface, increased with the increase in sample activation and the adsorption temperatures.