Agitated tank biosorption of ibuprofen using corn cob

Abstract

The presence of emerging contaminants, especially drugs for human and veterinary use in natural waters, due to their high degree of persistence and the fact that the treatments used in wastewater treatment plants (WWTP) are not efficient at removing them, has been the subject of study by the scientific community. In this work, the removal of ibuprofen from synthetic waters was studied working in an stirred tank using corn cob residues as a biosorbent. Aiming to achieve the highest drug removal rates, several parameters where studied such as: the concentration of biosorbent, the particle size of the biosorbent, the minimum contact time between both adsorbate and biosorbent to reach the equilibrium, the optimum pH and the temperature. The best conditions to remove ibuprofen (20 mg/L) from synthetic water were the use of 15 g/L of corn cobs with a particle size of 0.4191 mm stirring for one hour at pH 6.0. No matter the temperature, a removal rate of 50% was obtained after 10 minutes of contact, reaching an 89% at the equilibrium. A kinetic study showed that the pseudo-second-order kinetic model was the one that best reproduced the experimental data with a determination coefficient (R2) of 0.982, and for the equilibrium behavior, the Freundlich model was the best fit for the adsorption equilibrium data with a R2 of 0.972.