Efficient Removal of Tetracycline from Aqueous Solutions by a Green Biomass Adsorption Material: Cotton Fabric-Supported Fe@ Tannin-Based Polyphenol Network

To address the challenges in antibiotic wastewater treatment, this study developed a green and efficient adsorbent based on biomass material. A polyphenol network was formed by the grafting polymerization of hydroxymethyl tannin on the surface of cotton fabric. The cotton fabric-supported Fe@tannin-based polyphenol network (CF@Fe–MPNs) was prepared by the complexation of the polyphenol network with iron ions, and the adsorption performance of CF@Fe–MPNs for tetracycline (TC) was investigated. The adsorption of CF@Fe–MPNs for TC primarily occurred through hydrogen bonding, π–π interactions, and electrostatic interactions, with a maximum adsorption capacity of 146.52 mg/g. The adsorption process followed the Langmuir isothermal model and pseudo-second-order kinetics. Thermodynamic analysis revealed that the adsorption was spontaneous and endothermic. Moreover, CF@Fe–MPNs exhibited excellent reusability over multiple adsorption–desorption cycles, demonstrating their potential as an efficient and sustainable adsorbent for antibiotic removal.