Valoração de lodo de indústria de celulose para desenvolvimento de hidrogel com potencial para a adsorção de bromazepam em meio aquoso

Abstract

Water contamination by pharmaceutical residues, particularly benzodiazepines such as bromazepam (BZP), represents a critical environmental challenge due to their pseudo-persistence and potential neurotoxic risks to non-target organisms. Addressing the limitations of conventional wastewater treatment plants, this study is structured across two primary pillars. Initially, a systematic review identified a significant knowledge gap regarding the application of waste-derived bioadsorbents specifically targeted for pharmaceutical sequestration. Subsequently, we present the unprecedented development of a hybrid hydrogel synthesized through the upcycling of pulp and paper industry sludge into -crosslinked sodium alginate beads. BZP sequestration was evaluated in scenarios 1 a 10 mg L-1. The material exhibited a rough filamentous surface and an interconnected 3D porous network with a mesoporous texture (SSA de 9,35 m² g-1) and an amphoteric character (pHPZC= 8,04). Kinetic assays revealed a rapid initial uptake reaching a maximum experimental capacity of 0.26 mg g-1, with the Elovich model providing the superior statistical fit (R² = 0,994; AIC = -56.9). This confirms that adsorption occurs on energetically heterogeneous sites governed by coverage-dependent rate decay. Equilibrium behavior followed the Freundlich regime at 25 °C and transitioned to a linear (Henry-type) partition-controlled mechanism at higher temperatures. Furthermore, efficient regeneration using 0.1 M HCl allowed for sustained performance across multiple cycles. These findings validate the potential of industrial waste-derived hydrogels as a sustainable, zero-waste strategy for emerging contaminant remediation, directly supporting circular economy objectives."