Diclofenac sorption from synthetic water: Kinetic and thermodynamic analysis
Stefano Salvestrini, Angelo Fenti, Simeone Chianese, Pasquale Iovino, Dino Musmarra
Abstract
This work investigated diclofenac sorption on 0.5 g L−1 activated carbon in a range of temperature (288−318 K) and of initial sorbate concentration (24−218 mg L−1). Thermodynamic modelling was carried out with the Langmuir isotherm. For kinetic modelling we compared the so-called Diffusion-Controlled Langmuir Kinetics (DCLK) and the pseudo-second order (PSO) model. The maximum sorption capacity of the sorbent, equal to 180 mg g−1, was independent of temperature. Experimental data fitted well with both kinetic models, yet the DCLK model was found to be more informative about the mechanism of the process. Kinetic parameters (α, β) increased with the temperature, with α value rising from 5 × 10−5 to 20 × 10−5 L mg−1 min−0.5, and β value rising from 3 × 10−6 to 20 × 10−6 L mg−1 min−1 in the temperature range investigated.