Bioinspired chitosan/PVA beads cross-linked with LTH-doped bacterial cellulose hydrochar for high-efficiency removal of antibiotics.

This study presents the development of eco-friendly, bioinspired Chitosan (CS)/Polyvinyl alcohol (PVA) composite beads cross-linked with layered triple hydroxide (LTH) doped bacterial cellulose microfilament (BCM) Hydrochar as a highly efficient adsorbent for removing Vancomycin (VAN) and Azithromycin (AZM) from aqueous solutions. The composite beads were synthesized using a bioinspired approach that integrates 1D BCM Hydrochar and 2D LTH plates into a 3D hybrid structure, offering high porosity, diverse functional groups, and pH sensitivity. The adsorbents were characterized using FTIR, EDX, SEM, XRD, and zeta potential analysis. Optimal adsorption conditions, including 60 min of contact time, 0.133 g·L-1 dosage, and pH levels of 8 for VAN and 8.5 for AZM, achieved maximum adsorption capacities of 1845 mg·g-1 for AZM and 2182 mg·g-1 for VAN at a 500 mg·L-1 concentration. The adsorption mechanisms involved physisorption and chemisorption, influenced by surface heterogeneity and interactions. VAN exhibited stronger adsorption, while AZM displayed more uniform adsorption due to weaker interactions. The adsorbent retained high adsorption capacity across multiple regeneration cycles and demonstrated resilience in the presence of coexisting compounds, making it suitable for long-term wastewater treatment. This work highlights the promise of carbohydrate-derived, sustainable LTH@BCM char-CS/PVA composite beads as high-capacity adsorbents, offering an effective, eco-friendly solution for mitigating pharmaceutical pollutants in water.