Sequestration of Amoxicillin from Wastewater using PEGylated Al2O3–Fe2O3 Biomass-Based Nanosorbent: Comparative and Antimicrobial Studies

Abstract

The persistence of antibiotics in the water bodies is a critical issue for both the environment and human health. This study employed the wet-impregnation synthesis of Al 2 O 3 -Fe 2 O 3 -CaO (AlFe) and PEGylated Al 2 O 3 -Fe 2 O 3 -CaO (PEG@AlFe) nanosorbents to sequester amoxicillin (AMX) from wastewater. The biosorbents are characterized using FTIR, XRD, SEM, EDX, and pHpcz analysis. Batch adsorption was carried out, and an antimicrobial study was conducted on Staphylococcus aureus ( S. aureus ) and Escherichia coli (E. Coli) . FTIR recorded the presence of Al-O, Fe-O, and Ca-O stretches at 400 – 800 cm -1 . The SEM and XRD show crystalline, plate-like crystallites (AlFe) and elongated, rod-like particles (PEG@AlFe). pHpzc values of 11.68 (AlFe) and 12.47 (PEG@AlFe) are noted. The adsorption studies recorded an optimal performance with 98% AMX uptake at pH 6, 60 min, and 328 K by AlFe. While PEG@AlFe recorded 72% uptake at pH 8, 120 min. Both recorded negative ΔG°, while AlFe recorded positive ΔH° and ΔS°, and PEG@AlFe recorded negative ΔH° and ΔS°. PEG@AlFe fits the pseudo-first-order model (R 2 = 0.976) and AlFe conformed to pseudo-second-order models (R 2 = 0.995). AlFe is best described by the Langmuir isotherm at q m = 3340.12 mg g -1, while PEG@AlFe best fits the Freundlich isotherm (q m = 666.496 mg g -1 ). ZI values of 18±0.9 and 14±0.5 mm on S. aureus and E. coli, respectively, at 25 μg/mL for AlFe, while PEG@AlFe recorded 12 ± 0.5 and 13 ± 0.9 mm at 25 μg/mL. Both nanosorbents show promising potential to serve as sustainable materials and biofilters for wastewater treatment.