Bioinspired Hydrophobicity via Temperature-Induced Phase Separation of Beeswax: A Pathway for Developing Cellulose Nanofiber-Based Adsorbents for the Removal of Conventional Tetracycline Tablets

Cellulose nanofiber-based aerogels (CNFAs) hold immense promise across diverse fields, but their innate hydrophilicity and structural fragility in water have constrained their utility in water purification. This study introduces a green approach to induce hydrophobicity into CNFAs via thermally induced phase separation (TIPS) of beeswax, which was adhered to the nanofiber by hydrogen bonding and hydrophobic-hydrophobic interactions. The fabricated aerogel was characterized by using FTIR, SEM, XRD, TGA, contact angle, BET, and compression test. The resulting beeswax cellulose nanofiber-based aerogels (BCNFAs) possess a highly porous structure and extremely low density, enabling the aerogels to self-float and facilitate practical applications and recycling. Due to these remarkable characteristics, BCNFAs had excellent adsorption capacity within 10 min to effectively remove tetracycline (TC) from water with an adsorption capacity of 31.6 mg/g. The demonstrated methodology to induce hydrophobicity in CNFAs via TIPS of beeswax on CNFAs could be an eco-friendly and scalable approach for the fabrication of robust BCNFAs without using any toxic chemicals. So far, this is the first report on to make robust hydrophobic CNFAs by employing TIPS of beeswax while maintaining the porosity of CNFAs, which is highly desirable for effective TC tablet adsorption from water in the present context. The demonstrated work has commercial potential as it focuses on the practical utility of the modified aerogel for adsorbing conventional tetracycline tablets, rather than exclusively targeting the pharmaceutical ingredient alone.