High-Capacity Norfloxacin Capture by CMC/MIL-125(Ti)-NH₂: One-Pot Synthesis, Performance, and Synergistic Mechanisms

Norfloxacin (NOR), a recalcitrant antibiotic, poses significant threats to aquatic ecosystems and human health. Employing a facile one-pot hydrothermal approach, this work pioneers a novel three-dimensional carboxymethyl cellulose (CMC)/MIL-125(Ti)-NH₂ composite for ultraefficient NOR removal. The CMC scaffold effectively prevented nanoparticle aggregation and structural collapse of MIL-125(Ti)-NH₂, significantly enhancing the active site accessibility. The optimized composite (CMC/MIL-125(Ti)-NH₂-300) demonstrated exceptional adsorption capacities of 1251.8 mg/g (55 °C), substantially exceeding those of its individual components (CMC: 39.5 mg/g; MIL-125(Ti)-NH₂: 174.9 mg/g). The material achieved >90% NOR removal at concentrations ≤100 mg/L, exhibited rapid adsorption kinetics (best fitted by Elovich model, R² = 0.996), maintained robust performance across pH 3–10, and showed excellent cyclic stability of 92.4% adsorption capacity retention after 5 regeneration cycles. Combined density functional theory (DFT)/Multiwfn analyses deciphered synergistic adsorption mechanisms governed by electrostatic forces, π–π stacking, multihydrogen bonding, and van der Waals forces. This study delivers a high-performance and sustainable adsorbent for the remediation of antibiotic-contaminated wastewater.