Remoção de sulfametoxazol por adsorção em biocarvão ativado das folhas da mandioca (Manihot esculenta Crantz) em meio aquoso

Abstract

Drugs stand out among research as emerging contaminants because they have a great impact on the environment and human health. Sulfamethoxazole is an antibiotic that has physicochemical characteristics of fat solubility and low biodegradability, which makes it more likely to accumulate in the environment. The presence of this and other organic compounds can lead to the poor quality of water reaching human consumption, as water and sewage treatment plants cannot eliminate all the waste generated. Thus, this dissertation aimed to evaluate the removal of Sulfamethoxazole from the aqueous medium by means of the cassava (Manihot esculenta Crantz) leaves biochar, obtained from agroindustrial residues from local producers in the far west of Paraná, where production stands out in relation to other regions of Brazil. The physicochemical characterization of the biochar was performed by infrared analysis, zero charge potential, surface groupings determined by Boehm method and scanning electron microscopy. A factorial experimental design was performed using central composite design (DCC) and surface response methodology (MSR) in order to reduce the total number of experiments to obtain the best adsorption condition. The factors and their respective levels studied were pH (5, 6 and 7), adsorbent mass (50, 100 and 150 mg) and drug concentration (78.13; 156.25 and 234.38 mg.L-1). . They were then allowed to stir at 150 rpm for 12h at 25 ° C. After filtration and reading on the spectrophotometer, the final concentration and the adsorbed amount of the drug were calculated. After determining the optimum adsorption conditions, the adsorption kinetics experiment was performed. It was observed that pH did not significantly influence drug adsorption and that the best adsorption conditions were obtained with adsorbent mass and drug concentration of 50 mg and 78.13 mg.L-1, respectively. The best-fit kinetic model was pseudo-second order, with equilibrium being reached within 500 minutes.