Kinetics of diclofenac adsorption from aqueous solution on commercial activated carbon

Abstract

This paper studies the possibility of using activated carbon as an adsorbent for diclofenac (DFC) from aqueous medium. Batch sorption experiments were performed, and the influence of different parameters was studied: adsorbent dose, contact time and temperature. The experimentally obtained results were fitted according to two linear theoretical models of isotherms: Freundlich and Langmuir and according to two different kinetic models: pseudo-first and pseudo-second order. The optimal adsorption parameters were found to be: dose of adsorbent 0,5 g; contact time 60 minutes and temperature 20ºC, and the removal efficiency of diclofenac at these parameters was 92.8%.The results showed that the adsorption process follows a pseudo-second order kinetics and better matches the Freundlich isotherm model. The values of thermodynamic parameters indicate that adsorption process is spontaneous and exothermic. Based on the obtained data, it can be concluded that commercial activated carbon is an effective adsorbent for diclofenac from aqueous solution.

Keywords

• adsorption
• activated carbon
• potassium diclofenac
• isotherms
• kinetics