Efficient ethidium bromide removal using sodium alginate/graphene oxide composite beads: Insights into adsorption mechanisms and performance

Et+ entering this space in a horizontal or at least 45-degree oblique morphology. The accumulation of Et+ could consist of approximately 1 to 6 basic inclined Et+ layers. The electrostatic interaction, π-π stacking, and the hydrophobic property of molecules play significant roles in the adsorption mechanisms. [Display omitted] •Maximum EtBr adsorption capacity was as high as 2.97mmol g-1 (1171.05 mg g−1).•Electrostatic interactions between OH− and Et+ attributed to adsorption mechanism.•π-π stacking and hydrophobicity played significant roles in the adsorption mechanism.•Interlayer spacing expansion (4.3–5.6 Å) confirms Et+ cation intercalation.•SA/GO beads show rapid kinetics, high efficiency, improved mechanical stability. This study explores the efficacy of sodium alginate/graphene oxide (SA/GO) composite beads for ethidium bromide (EtBr) removal from aqueous solutions. GO was synthesized and crosslinked with SA to design composite beads, which were evaluated under various physicochemical conditions. Characterization techniques, including FESEM, TGA, XRD, and FTIR, were employed to analyze the beads before and after EtBr adsorption. Results demonstrated rapid EtBr adsorption onto SA/GO, following the Freundlich isotherm model with a maximum adsorption capacity of 2.97 mmol g−1 (1171.05 mg g−1). The influence of solution pH and the negligible role of Br− ions suggested that electrostatic interaction was the primary mechanism for EtBr adsorption on SA/GO. XRD and FTIR analyses revealed that EtBr adsorption also occurred in the interlayer space of SA/GO beads, with the ethidium cations (Et+) entering this space in a horizontal or oblique (≥45°) orientation. The accumulation of Et+ within the interlayer space was estimated to form 1–6 basic inclined layers. SA/GO beads demonstrated promising characteristics for EtBr pollutant treatment, including low environmental impact, cost-effectiveness, rapid adsorption kinetics, and high removal efficiency. This study provides valuable insights into the adsorption mechanisms and performance of SA/GO beads, highlighting their potential for future field applications in the environmental remediation of EtBr contamination.