Evaluation of the efficiency of the biochar prepared from the pine bark in removing diclofenac from aqueous solutions

In recent years, there has been a great deal of concern related to drug pollutants in water resources. The aim of this study was to evaluate the efficacy of the biochar obtained from the pine bark in removing of diclofenac from aqueous solutions.

In this batch study, the effect of various variables such as pH (2-12), adsorbent dose (0.1- 2 gr), initial concentration of diclofenac (50- 500 mg/L), contact time (10-120 min) and temperature (10- 50°C), as well :as char:acterization of the biochar were investigated with BET, FTIR and FESEM techniques. The isotherm, kinetics and thermodynamics of the adsorption process were evaluated.

The highest removal of diclofenac (80.4%) was at pH 6.2. In this study, the adsorption efficiency of diclofenac increased with increasing the adsorbent dose and decreased with increasing the initial concentration of diclofenac. The adsorption isotherm of diclofenac fitted to Langmuir model with maximum adsorption capacity was 54.64 mg/g. The kinetics of the adsorption process followed by the pseudo-second-order kinetic model and thermodynamic parameters showed the diclofenac adsorption onto the biochar was exothermic and spontaneous.

Based on the results, the adsorption efficiency of diclofenac by the biochar of the pine bark is suitable and it can be efficient for removal of diclofenac from hospital and other pharmaceutical compounds producers’ wastewaters.