Adsorption of ketoprofen and paracetamol and treatment of a synthetic mixture by novel porous carbon derived from Butia capitata endocarp

In this work, endocarp of the species Butia capitata was employed as precursor material to prepare a novel activated carbon with intrinsic properties to remove ketoprofen and paracetamol from water efficiently. The activated carbon presented a predominantly microporous structure, with an average pore diameter of 1.23 nm, a total pore volume of 0.449 cm(3) g(-1), and a high specific surface area, 820 m(2) g(-1). The adsorption kinetics showed a rapid initial decay for both pharmaceuticals, with the system entering equilibrium after 120 min for ketoprofen and 180 min for paracetamol. The pseudo-second-order model presented the best fit for ketoprofen and the Elovich model for paracetamol. The adsorption equilibrium data show that temperature can increase or decrease the adsorption capacity, being found a maximum adsorption capacity of 108.79 and 100.60 mg g(-1) for the ketoprofen and paracetamol, respectively. The Freundlich and Langmuir models presented the best statistical adjustments for the adsorption of ketoprofen and paracetamol, respectively. The thermodynamic analysis confirmed an endothermic process for ketoprofen (Delta H-0 = 11.98 kJ mol(-1)) and exothermic for paracetamol (Delta H-0 = -13.37 kJ mol(-1)). The recycle tests revealed that the adsorbent has an average decrease for removal percentage of only 1.88 % for ketoprofen and 1.57 % for paracetamol. Estimations costs indicate that the price of 1 kg of activated carbon costs is 2.39 USD at minimum. Last, the material presented a highly efficient adsorptive activity to treat a synthetic mixture containing several pharmaceutical compounds and salts, reaching 84.82% removal. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

In this study, activated carbon was prepared using endocarp of Butia capitata, showing efficient removal of ketoprofen and paracetamol from water. The activated carbon had a microporous structure with a high specific surface area and pore volume. Kinetics showed rapid adsorption for both pharmaceuticals, with equilibrium reached in 120 minutes for ketoprofen and 180 minutes for paracetamol.