Remoção de Prednisona por adsorção em carvão ativado obtido a partir do bagaço de Oliveira

Abstract

Contamination by drugs in water resources has drawn the attention of researchers since traditional treatments don’t provide the total removal of these substances from liquid effluents. The literature reports the presence of the drug prednisone in several effluent treatment plants, with the need to remove it. In the adsorption process, several types of adsorbent materials are used, such as activated carbons, which have a high surface area and high thermal stability, which can be obtained through the pyrolysis of plant residues. Thus, this work aimed to evaluate the potential use of activated carbon obtained from olive pomace to remove prednisone. Preliminary tests and an experimental design were carried out to study the effect of adsorbent dosage conditions, pH and initial prednisone concentration on removal and adsorption capacity. Afterwards, the adsorption kinetics were determined using initial prednisone concentration of 60 ppm and 10 ppm and equilibrium isotherm using a range of 25- 800 ppm. The adsorbent dosage chosen was 1.25 g.L-1 and natural pH around 5. The adsorption kinetics of prednisone presented equilibrium times of 120 min and 105 min, adsorption capacities of 7.923 mg.g-1 and 34.367 mg.g-1. The models that best fit the data were Elovich and Pseudo-first order with high determination coefficients (98.73 and 97.3%) and low relative errors (5.98 and 11.25%). for concentrations of 10 and 60 ppm, respectively. The adsorption isotherm showed a adsorption capacity of 166.71 mg.g-1 and the model that best represented the process was the Langmuir model, with a coefficient of determination of 93.96% and a maximum adsorption capacity of 176.06 mg.g-1. The results obtained showed a good performance of activated carbon from olive pomace for adsorption of the drug prednisone, which proved to be effective and viable for carrying out the process, making it possible to proceed with future work.