Statistical optimization studies on adsorption of ibuprofen onto Albizialebbeck seed pods activated carbon prepared using microwave irradiation

Abstract

Micro-pharmaceutical pollutant – ibuprofen was removed from aqueous solutions by Albizialebbeck seed pods activated carbon prepared using microwave irradiation (MSAC). The main and interactive effects of four process variables namely, adsorbent dose (0.2 – 0.4 g/L), initial ibuprofen concentration (50–100 µg/L), pH (6 – 10) and temperature (30 – 40οC) were studied via response surface methodology (RSM) based on central composite rotatable design. The optimum values of the key variables were estimated using Derringer’s desirability function. The optimal values were calculated to be at MSAC dose 0.33 g/L, initialibuprofen concentration 76.44 µg/L, pH 7.82, and temperature 37.48οC with maximum desirability of 100%. The equilibrium data obeyed Smith isotherm and indicated that the MSAC was heterogeneous and ibuprofen was adsorbed in multilayers. The kinetic investigation showed that the ibuprofen was chemisorbed on MSAC surface following Avrami fractional order kinetics. The thermodynamic factors showed that ibuprofen adsorption process was spontaneous and exothermic.