Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE This study prepared a 3D porous SF/Fe2O3 aerogel from silk waste via freeze-casting for tetracycline (TCH) adsorption. It achieved 87.47% removal at pH 5, following pseudo-first-order kinetics and the Freundlich model, with adsorption driven by hydrogen bonding, π–π interactions, and electrostatic forces. This offers a sustainable approach for both silk waste valorization and antibiotic removal from water.

ABSTRACT
The efficient removal of antibiotics from aquatic environments is crucial to safeguard both ecosystems and human health. Herein, silk fibroin/Fe2O3 (SF/Fe2O3) aerogel was fabricated from silk wastes and nano-sized Fe2O3 powders through freeze-casting and vacuum freeze-drying strategy. The resulting SF/Fe2O3 aerogel showed three-dimensional honeycomb-like porous structures. Benefiting from its porous structures and abundant active sites, SF/Fe2O3 aerogel exhibited outstanding adsorption performance toward tetracycline hydrochloride (TCH), enabling high-value recycling of silk wastes. Systematic studies on the effects of Fe2O3 weight percentages, initial TCH concentrations, adsorbent dosages, and pH values revealed that the aerogel achieved a high removal efficiency of 87.47% at pH 5. The adsorption kinetic and isothermal analyses demonstrated that the adsorption process of SF/Fe2O3 aerogel followed a pseudo-first-order adsorption kinetic model with R
2 = 0.9726 and a Freundlich model with R
2 = 0.9682, suggesting spontaneous heterogeneous multilayer physisorption. The adsorption mechanism was dominated by electrostatic interactions, hydrogen bonding, π–π interactions, cation bridging, and hydrophobic forces between SF/Fe2O3 aerogel and TCH. This study provides a green and sustainable route for the utilization of silk wastes and offers a promising strategy for antibiotic removal in aquatic environments.