Adsorption of naphthenic acids on peanut shell activated carbon: Batch and fixed-bed column study of the process

Abstract

This study reports the adsorption of the naphthenic acids (NA) presents in an aviation kerosene (AVK) model mix using adsorbents prepared from peanut shell (PS). Both carbonization and the CO2 activation of the PS favored the adsorptive process. In the factorial design, the activated carbon prepared presented the highest adsorptive capacity for the lowest levels of the variables studied (<0.09 mm and without agitation). The adsorption equilibrium after 360 min, and the process is not only controlled by the intraparticle diffusion step. The adsorption isotherm was best fitted to Langmuir model with a maximum adsorbed amount of 884 mg g−1, whose heat of adsorption indicated that the process was of the physisorption. In the continuous adsorption study, it was verified that the increase of the flow and the concentration of NA decreased the rupture time. The breakthrough time and adsorptive capacity were reduced at each adsorption/desorption cycle. Given the shortage of works on this topic in literature, this study contributes with new findings that describe naphthenic acid adsorption in AVK.