Improvement of activated carbon characteristics by sonication and its application for pharmaceutical contaminant adsorption

Abstract

Sonicated activated carbon (SAC) was developed and used to remove ibuprofen and ketoprofen from aqueous media by adsorption. A standard activated carbon sample (AC) was used as comparison. Both adsorbents were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), N₂ adsorption isotherms (Brunauer, Emmett, and Teller (BET)), helium gas pycnometry, and scanning electron microscopy (SEM). In the adsorption study, kinetics, equilibrium, and thermodynamics were evaluated. SAC presented better characteristics than AC. Pseudo-second-order model was adequate to predict the kinetic curves. The isotherm data obeyed the Sips model. Thermodynamic results revealed a spontaneous and endothermic process, where physisorption was involved. The maximum adsorption capacities of SAC were 134.5 and 89.2 mg g⁻¹ for ibuprofen and ketoprofen, respectively. For AC, the maximum adsorption capacities were 115.1 and 79.1 mg g⁻¹ for ibuprofen and ketoprofen, respectively. The sonication technique presented great potential to improve the AC characteristics, generating a promising material (SAC) for ibuprofen and ketoprofen adsorption.