Highly Efficient Removal of Tetracycline from Water Using Ce-UiO-66/Oxidized Nanodiamond Hybrids

Tetracycline (TC) is one of the most widely used antibiotics in both human and veterinary medicine. However, its presence in ecosystems creates serious environmental concerns. This study investigates the adsorption of TC using a green-synthesized adsorbent that is composed of a Cerium-based metal-organic framework (Ce-UiO-66 MOF) integrated with an oxidized nanodiamond (OND). The adsorbents were synthesized using a green- and water-based method. Among all composites, Ce-UiO-66/OND-2 (containing 2% OND) achieved an experimental adsorption capacity of 342 mg/g─an approximately 63% enhancement compared to that of the pristine Ce-UiO-66 (210 mg/g). This is attributed to synergistic interactions between the MOF and OND. Reusability tests showed that Ce-UiO-66/OND-2 maintained ≈68% of its initial adsorption capacity after four adsorption-desorption cycles, which shows noticeable reusability and long-term stability. Overall, these findings highlight the potential of OND-integrated Ce-MOFs as sustainable and high-capacity adsorbents for antibiotic-contaminated water treatment.