Coadsorbent boosts Caragana-derived carbon for breakthrough antibiotic capture in a robust nanosheet-on-carbon architecture

Antibiotic pollutants, even at trace levels, pose a significant threat to ecosystems and human health by fostering drug resistance and the emergence of lethal superbugs. Herein, a flower-like nanosheet-on-carbon heterogeneous architecture (N750-LDH) was developed by integrating layered double hydroxide (LDH) as a coadsorbent onto Caragana carbon. Structural characterization and site energy distribution analysis reveal that this design not only increases the number of surface adsorption sites but also enhances adsorption driving forces such as electrostatic interactions, hydrogen bonding, and ion-exchange through the synergy of active carbon and LDH. This significantly boosts mass-transfer efficiency, thereby increasing the adsorption capacity for doxycycline hyclate (DCH) by 28 fold—from 30 mg/g for the original carbon to 840 mg/g for N750-LDH. Furthermore, N750-LDH achieves a remarkably high removal efficiency (99.99 %) for DCH (concentration: 50 mg/L) using just 0.4 g/L of the composite, outperforming commercial activated carbons. Even under real-world water conditions with co-existing ions, N750-LDH retains its high adsorption capacity for DCH. Additionally, it is recyclable, retaining over 90 % of its initial adsorption efficiency after five cycles. The exceptional performance of N750-LDH, coupled with the abundant availability of raw materials, low cost, and environmental benefits, highlights its considerable potential for decontaminating antibiotic pollutants from water.