Chitin-supported electrospun polylactic acid-polystyrene hybrid membrane impregnated with a ternary layered double...

A novel bio-based composite adsorbent was prepared by electrospinning polylactic acid/polystyrene (PLA/PS) nanofibers, doped with nickel-strontium-lanthanum layered double hydroxide (NiSrLa LDH), onto chitin nanofibers. The fabricated adsorbent (PLA/PS-LDH@ChNF) was employed for the efficient removal of amoxicillin (AMX) from hospital wastewater, with quantification performed via HPLC-UV. The structural properties of the adsorbent were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), nitrogen adsorption-desorption isotherms, and thermal analysis. The effects of significant parameters influencing the adsorption process, including adsorbent dosage, solution pH, ionic strength, contact time, and initial concentration were systematically investigated. Under optimized conditions, the adsorbent exhibited a high removal efficiency (98 %) and a maximum adsorption capacity of 322.58 mg/g. The adsorption process followed pseudo-second-order kinetics and was best described by the Freundlich isotherm model, suggesting multilayer adsorption on a heterogeneous surface. Thermodynamic analysis based on ΔG°, ΔH°, and ΔS° values confirmed that the adsorption of AMX was spontaneous and endothermic. The synthesis yield, cost-effectiveness, and regeneration of the adsorbent were also investigated. Finally, the environmental sustainability of the process was assessed using Analytical GREEnness metric (AGREE), Green Analytical Procedure Index (GAPI), and Biosorption Assessment Green Index (BAGI). This study represents the first report on the synthesis and application of PLA/PS-LDH@ChNF for AMX removal from hospital effluents, achieving removal efficiencies of 92.9-97.2 % in real wastewater samples, with relative standard deviations (RSDs) ranging from 2.5 to 6.8 %.