Polymer-modified nano-Al2O3 for efficient levofloxacin removal: Mechanisms and environmental implications

• Adsorption of LFX on α-Al 2 O 3 and γ-Al 2 O 3 with surface modification by two polyanions was investigated. • The conditions for LFX removal using 20 mg/mL PAMPs modified α-Al 2 O 3 were pH 7, and contact time 90 min. • The best conditions for LFX removal were pH 8, contact time 120 min using 10 mg/mL PAPS modified γ-Al 2 O 3 . • High maximum adsorption capacites of LFX on polyanions modified-Al 2 O 3 reached 21 and 33 mg/g. Removal of emerging antibiotic is of great importance because antibiotic resistance is serious problem for human health. Novel adsorbents are atttracted intense study but very few study has been investigated the performance of different phase structures of adsorbent with surface modification by polymer. This study investigated the adsorption characteristics of the antibiotic levofloxacin (LFX) on α-Al 2 O 3 and γ-Al 2 O 3 nanoparticles modified with poly (2-acrylamide-2-methylpropane sulfonic acid) (PAMPs) and poly (3-sulfopropyl acrylate potassium) (PAPS). Surface modifications of α-Al 2 O 3 and γ-Al 2 O 3 by the adsorption of two polyanions significantly enhanced LFX removal efficiencies. Zeta potential measurements revealed that the surface charge of α-Al 2 O 3 reversed from positive to highly negative after modification with PAMPs, while γ-Al 2 O 3 underwent a similar charge reversal after modification with PAPS. Fourier-transform infrared spectroscopy confirmed the appearance of key functional groups C=O and N-H in PAMPs, and C=O and C-O in PAPS, indicating successful polymer adsorption on the nano-Al 2 O 3 surface. The optimal conditions for LFX removal using 20 mg/mL PAMPs modified α-Al 2 O 3 and 10 mg/mL PAPS modified γ-Al 2 O 3 were found to be pH 7, adsorption time 90 min and pH 8, adsorption time 120 min, respectively. Adsorption isotherms followed a two-step adsorption process, while adsorption kinetics were best described by the pseudo-second-order model. Both modified adsorbents achieved LFX removal efficiencies exceeding 85 %, with maximum adsorption capacities of over 20 mg/g, values significantly higher than many other adsorbents. Furthermore, the modified adsorbents demonstrated high removal efficiencies of LFX in actual water samples, achieving recoveries of greater than 80 %. These findings highlight the potential of polymer-modified α-Al 2 O 3 and γ-Al 2 O 3 nanoparticles as high-performance materials for antibiotic removal.