Valorization of hawthorn seed waste through solid phase extraction of antibiotics from water samples
Résumé
Removing pollutants from contaminated water is crucial for maintaining a disease-free and healthy society. The potential of a novel, cost-effective hydrochar was explored for extracting antibiotics from aqueous environments. The study employed both experimental and theoretical approaches. Agricultural waste, specifically hawthorn seeds hydrochar was prepared via hydrothermal carbonization and was characterized using IR and SEM-EDX analyses. Solid-phase extraction (SPE) of metronidazole and levofloxacin was investigated, followed by their determination using high-performance liquid chromatography (HPLC). An experimental design optimized the SPE process, focusing on sample volume, elution volume, and type of elution solvent to enhance antibiotic extraction efficiency. The optimal conditions of SPE extraction included 50 mL of sample solution, and 5 mL of methanol as the elution solvent type. The best separation was achieved with isocratic elution utilizing a mobile phase consisting of acetonitrile-water (pH = 4) with 0.4% triethylamine 25:75 (V/V). The identification of antibiotics was carried out using diode array detection, with calculations performed for the linear range, the limit of detection (LOD), and the limit of quantification (LOQ). The LOD and LOQ ranged from 0.13 to 0.2 μg.L -1 and from 0.62 to 0.87 μg.L -1 , respectively. Using actual water samples, researchers evaluated the effectiveness of the optimized solid-phase extraction (SPE) method. The recoveries were exceeded 96%, with a relative standard deviation (RSD) below 9.5%, demonstrating the minimal interference from the sample matrix and confirming the robustness of the method. Additionally, a computational study for the investigation of the sorption mechanism, interaction energies, and distances between the adsorbent and adsorbate was done.
Keywords
Solid phase extraction (SPE) • Mixed matrix design experimental • Hawthorn seeds hydrochar • Antibiotics • HPLC-UV • Surface water • DFT calculation * Latifa Latrous