Neomycin antibiotic removal by antimicrobial nanobiosorbent based on sodium alginate-grafted-poly(3-aminophenol)/silver-decorated metal-organic frameworks

Abstract

Antibiotics, widely used in human and animal medicine, pose a significant threat to water quality due to their persistent presence even after use. Their insolubility in water and resistance to conventional removal methods exacerbate their environmental impact. This study aimed to develop an antimicrobial composite, alginate-grafted-poly(3-aminophenol)/silver-decorated metal-organic framework (SA-g-P3AP@MOF(Fe)/Ag) via an in-situ copolymerization technique. This composite proved effective in removing neomycin from contaminated water. Characterization via FTIR, XRD, BET, and TGA analyses confirmed the composite's structure and properties. Under optimized conditions (pH = 7, 30-minute contact time, 5 mg adsorbent amount, 25 °C temperature, and 700 mg/L pollutant concentration), the composite removed 87 % of neomycin from water samples. The interaction between neomycin and the composite aligned with the Freundlich isotherm, exhibiting a maximum adsorption capacity (Q_max) of 625 mg/g, and adhered to the pseudo-second-order kinetic. Thermodynamic analysis indicated the exothermic and spontaneous nature of neomycin adsorption onto the synthesized composite. The proposed adsorption mechanism centered on intermolecular interactions between amine, alcohol, and imine functional groups of the SA-g-P3AP@MOF(Fe)/Ag and neomycin antibiotic. The incorporation of MOF(Fe)/Ag with its highly porous structure significantly bolstered neomycin adsorption, enhancing the antibacterial effectiveness of SA-g-P3AP@MOF(Fe)/Ag.