RESUMO
Framed in the problem of emerging pollutants, in this work we introduce a novel procedure for the total removal of amoxicillin from water samples using magnetic nanoparticles functionalized with nanometric silver (Fe3O4@AgNPs). Experimental conditions such as pH, contact time, temperature, as well as adsorbate and adsorbent doses have been studied to achieve the total adsorption for different concentrations of amoxicillin in water. Particularly, for concentrations 10 and 100 mg L-1, a maximum removal efficiency of 100% was reached at room temperature and pH = 7 after 15 min of contact time between adsorbent and water samples under gentle shaking. The doses of adsorbent employed to remove 10 and 100 mg L-1 of amoxicillin were 100 and 500 µL, respectively. Characterization of the adsorbent surfaces was performed by Scanning and Transmission Electron Microscopy, Energy Dispersive X-ray Spectroscopy, BET analysis and Fourier-transform infrared spectroscopy. Recycling studies were carried out employing 500 µL of NaOH solution 1 M during 15 min in order to explore desorption and reuse of the adsorbent, showing that Fe3O4@AgNPs remains unaltered and can be used for two more additionally adsorption cycles, exhibiting 93% adsorption efficiency after the third regeneration. The characterization of equilibrium isotherms and thermodynamics reveal a Langmuir-type endothermic chemisorption.
