Metal organic framework–derived recyclable magnetic coral Co@Co3O4/C for adsorptive removal of antibiotics from wastewater.

The menace posed by antibiotic contamination to humanity has increased due to the absence of efficient antibiotic removal processes in the conventional waste water treatment methods from the hospitals, households, animal husbandry, and pharma industry. Importantly, only a few commercially available adsorbents are magnetic, porous, and have the ability to selectively bind and separate various classes of antibiotics from the slurries. Herein, we report the synthesis of a coral-like Co@Co₃O₄/C nanohybrid for the remediation of three different classes of antibiotics — quinolone, tetracycline, and sulphonamide. The coral like Co@Co₃O₄/C materials are synthesized via a facile room temperature wet chemical method followed by annealing in a controlled atmosphere. The materials demonstrate an attractive porous structure with an excellent surface-to-mass ratio of 554.8 m² g⁻¹ alongside superior magnetic responses. A time-varying adsorption study of aqueous nalidixic acid solution on Co@Co₃O₄/C nanohybrids indicates that these coral-like Co@Co₃O₄/C nanohybrids could achieve a high removal efficiency of 99.98% at pH 6 in 120 min. The adsorption kinetics data of Co@Co₃O₄/C nanohybrids follow a pseudo-second-order reaction kinetics suggesting a chemisorption effect. The adsorbent has also shown its merit in reusability for four adsorption-desorption cycles without showing significant change in the removal efficiency. More in-depth studies validate that the excellent adsorption capability of Co@Co₃O₄/C adsorbent attributing to the electrostatic and π–π interaction between adsorbent and various antibiotics. Concisely, the adsorbent manifests the potential for the removal of a wide range of antibiotics from the water alongside showing their utility in the hassle-free magnetic separation. [ABSTRACT FROM AUTHOR]