Enhanced tetracycline removal from aqueous systems using starch-functionalized iron-graphene oxide nanocomposites:...

The increasing presence of tetracycline antibiotics in aquatic ecosystems poses a critical environmental challenge, necessitating innovative remediation strategies. This study presents the development and characterization of starch-functionalized iron-graphene oxide (SFIGO) and starch-functionalized iron oxide (SFIO) nanocomposites adsorbents for tetracycline removal from water, with emphasis on sustainable synthesis and enhanced performance. Biluochun tea and cassava extract were used as renewable precursors in green synthesis to create a composite material that combines iron oxide's magnetic properties, graphene oxide's high surface area, and starch's biocompatibility. Comprehensive characterization using FTIR, XRD, SEM-EDX, TEM, and XPS revealed SFIGO's unique hierarchical architecture, featuring wrinkled graphene oxide sheets with well-dispersed iron-oxide nanoparticles. Batch adsorption studies demonstrated SFIGO's superior performance, achieving a maximum adsorption capacity of 865.79 mg/g at 298 K, significantly higher than SFIO's 634.83 mg/g. The adsorption process followed pseudo-second-order kinetics and showed endothermic behavior, with negative Gibbs free energy values, confirming process spontaneity. Multiple binding mechanisms, including π-π interactions, electrostatic attractions, and surface complexation, contributed to SFIGO's enhanced performance. The material demonstrated robust performance across various water matrices and maintained high removal efficiency. These findings advance our understanding of composite materials in environmental remediation and provide a sustainable solution for pharmaceutical pollutant removal.