Adsorção de anti-hipertensivos do meio aquoso por biocarvões preparados de resíduos vegetais após estudos de predição e priorização de fármacos

Abstract

Pharmaceutical compounds have been widely detected as emerging contaminants (EC) in aquatic environments, standing out for their persistence, low biodegradability, and potential risks to health and ecosystems, even at low concentrations. Approximately 80% of global wastewater does not receive adequate treatment, contributing to the continuous release of these compounds, since part of the administered doses is excreted unchanged or as active metabolites. Among alternative technologies, biosorption has stood out for its efficiency, low cost, and sustainability. In this context, the present work proposed a systematic step for predicting and prioritizing pharmaceuticals, based on the integration of criteria of environmental occurrence, toxicity, and consumption data, to identify and select compounds of greater environmental relevance in the state of São Paulo. From this process, the antihypertensive drugs methyldopa (MDP) and doxazosin (DOX) were selected. For their removal, carbonaceous biosorbents, CL and BC, were developed from yeast residues and cork powder, respectively, which were modified with magnetic nanoparticles (NP), resulting in the magnetic bionanocomposites CL-NP and BC-NP. The materials obtained were characterized by FTIR, XRD, SEM, and determination of the pH at the point of zero charge (pHPZC). Batch adsorption tests evaluated the effects of solution pH, contact time, biosorbent dosage, and sorption capacity. The results indicated that sorption was favorable across the entire pH range investigated (6-10), and that a dosage of 0.5 g L–1 showed the best performance in the tests. Equilibrium was reached in approximately 30 minutes, with a better fit to the pseudo-second-order kinetic model, suggesting a process predominantly controlled by chemisorption. Sorption capacities ranged from 7.48 to 38.76 mg g–1, and equilibrium data indicated the presence of heterogeneous surfaces. Therefore, the developed biosorbents demonstrated high potential in removing the prioritized pharmaceuticals, highlighting the importance of the prediction and prioritization step, and reinforcing the viability of using agro-industrial waste as an efficient, accessible, and environmentally sound strategy for treating contaminated water.