The Use of Biochar in Reducing Contamination of Soils in Agreste Pernambucano Region by Sulfamethoxazole and Sulfadiazine

Around 30 to 90% of administered antibiotics are not fully metabolized and, therefore, pose risks to the quality of groundwater. In this way, the objective was to understand the sorption behavior of SDZ and SMX, in sandy soil from the Agreste of Pernambuco, to reduce the contamination of groundwater. For this, batch tests were carried out on soils collected in Agreste Pernambuco in two extracts, one at 0 - 20 cm and the other at 20 - 40 cm deep, with and without the addition of biochar. The results showed that the addition of biochar to the soil led to an increase in sorption of both SDZ and SMX, reaching approximately 73 and 123 mg kg-1, in the case of soil from the 0 - 20 cm layer, respectively. In the case of the 20 - 40 cm layer, SDZ sorption exceeded 102 mg kg-1, while for SMX it exceeded 95 mg kg-1. Furthermore, the reaction equilibrium times for SDZ and SMX were the same in the case of soils from the same layer, with or without the addition of biochar, however in the case of SMX these times were shorter (12h). It was also noted that at low pH values (pH < 4) the sorption of the two antibiotics is greater, showing a dependence of sorption on the pH of the solution. As a result, it became clear that these antibiotics have high mobility, indicating an imminent risk of contamination of soil and surface and groundwater.