Kinetics and isotherm studies on the adsorption of an antiparkinsonism drug Entacapone from aqueous solutions using unsaturated polyester resin (UPR)

Abstract

Growing concern about environmental issues has prompted the pharmaceutical industry to investigate appropriate and environmentally friendly treatment technologies. Removal of pharmaceuticals by adsorption is one of the most promising techniques, due to its convenience. In the present communication adsorption of Entacapone from wastewater using low-cost non-carbon adsorbent unsaturated polyester resin (UPR) has been reported. Results showed that adsorption of Entacapone onto UPR have some advantages such as high adsorption capacity and short adsorption time. Different thermodynamic parameters like Gibb’s free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) of the undergoing process have also evaluated through these adsorption models. The estimated values for ΔG° were −11.953 × 10³ kJ mol⁻¹ over UPR at 303 K (30°C) indicate toward a spontaneous process. The rate equations showed that the adsorption kinetic data generally fitted the rate equations from which the rate constants and diffusion rate constants were evaluated. However, the Lagergren pseudo first-order rate equation gave the best fit, and thus the process followed first-order rate kinetics.

Keywords:

• Adsorption
• Kinetics
• Isotherms
• Entacapone
• UPR