Adsorption Studies on Magnetic Nanoparticles Functionalized with Silver to Remove Nitrates from Waters
This paper presents a novel procedure for the treatment of contaminated water with high concentrations of nitrates, which are considered as one of the main causes of the eutrophication phenomena. For this purpose, magnetic nanoparticles functionalized with silver (Fe<sub>3</sub>O<sub&...
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MDPI AG
2021-06-01
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author | Yesica Vicente-Martínez Manuel Caravaca Antonio Soto-Meca Miguel Ángel Martín-Pereira María del Carmen García-Onsurbe |
author_facet | Yesica Vicente-Martínez Manuel Caravaca Antonio Soto-Meca Miguel Ángel Martín-Pereira María del Carmen García-Onsurbe |
author_sort | Yesica Vicente-Martínez |
collection | DOAJ |
description | This paper presents a novel procedure for the treatment of contaminated water with high concentrations of nitrates, which are considered as one of the main causes of the eutrophication phenomena. For this purpose, magnetic nanoparticles functionalized with silver (Fe<sub>3</sub>O<sub>4</sub>@AgNPs) were synthesized and used as an adsorbent of nitrates. Experimental conditions, including the pH, adsorbent and adsorbate dose, temperature and contact time, were analyzed to obtain the highest adsorption efficiency for different concentration of nitrates in water. A maximum removal efficiency of 100% was reached for 2, 5, 10 and 50 mg/L of nitrate at pH = 5, room temperature, and 50, 100, 250 and 500 µL of Fe<sub>3</sub>O<sub>4</sub>@AgNPs, respectively. The characterization of the adsorbent, before and after adsorption, was performed by energy dispersive X-ray spectroscopy, scanning electron microscopy, Brunauer-Emmett-Teller analysis and Fourier-transform infrared spectroscopy. Nitrates can be desorbed, and the adsorbent can be reused using 500 µL of NaOH solution 0.01 M, remaining unchanged for the first three cycles, and exhibiting 90% adsorption efficiency after three regenerations. A deep study on equilibrium isotherms reveals a pH-dependent behavior, characterized by Langmuir and Freundlich models at pH = 5 and pH = 1, respectively. Thermodynamic studies were consistent with physicochemical adsorption for all experiments but showed a change from endothermic to exothermic behavior as the temperature increased. Interference studies of other ions commonly present in water were carried out, enabling this procedure as very selective for nitrate ions. In addition, the method was applied to real samples of seawater, showing its ability to eliminate the total nitrate content in eutrophized waters. |
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language | English |
last_indexed | 2024-03-10T10:02:32Z |
publishDate | 2021-06-01 |
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spelling | doaj.art-45208580eb8840e998d20357e494db6a2023-11-22T01:46:02ZengMDPI AGWater2073-44412021-06-011313175710.3390/w13131757Adsorption Studies on Magnetic Nanoparticles Functionalized with Silver to Remove Nitrates from WatersYesica Vicente-Martínez0Manuel Caravaca1Antonio Soto-Meca2Miguel Ángel Martín-Pereira3María del Carmen García-Onsurbe4Department of Science, University Centre of Defence at the Spanish Air Force Academy, Ministry of Defence-Technical University of Cartagena, C/Coronel López Peña s/n, Santiago de la Ribera, 30720 Murcia, SpainDepartment of Science, University Centre of Defence at the Spanish Air Force Academy, Ministry of Defence-Technical University of Cartagena, C/Coronel López Peña s/n, Santiago de la Ribera, 30720 Murcia, SpainDepartment of Science, University Centre of Defence at the Spanish Air Force Academy, Ministry of Defence-Technical University of Cartagena, C/Coronel López Peña s/n, Santiago de la Ribera, 30720 Murcia, SpainDepartment of Science, University Centre of Defence at the Spanish Air Force Academy, Ministry of Defence-Technical University of Cartagena, C/Coronel López Peña s/n, Santiago de la Ribera, 30720 Murcia, SpainCampus Alfonso XIII, Technical University of Cartagena, 30203 Cartagena, SpainThis paper presents a novel procedure for the treatment of contaminated water with high concentrations of nitrates, which are considered as one of the main causes of the eutrophication phenomena. For this purpose, magnetic nanoparticles functionalized with silver (Fe<sub>3</sub>O<sub>4</sub>@AgNPs) were synthesized and used as an adsorbent of nitrates. Experimental conditions, including the pH, adsorbent and adsorbate dose, temperature and contact time, were analyzed to obtain the highest adsorption efficiency for different concentration of nitrates in water. A maximum removal efficiency of 100% was reached for 2, 5, 10 and 50 mg/L of nitrate at pH = 5, room temperature, and 50, 100, 250 and 500 µL of Fe<sub>3</sub>O<sub>4</sub>@AgNPs, respectively. The characterization of the adsorbent, before and after adsorption, was performed by energy dispersive X-ray spectroscopy, scanning electron microscopy, Brunauer-Emmett-Teller analysis and Fourier-transform infrared spectroscopy. Nitrates can be desorbed, and the adsorbent can be reused using 500 µL of NaOH solution 0.01 M, remaining unchanged for the first three cycles, and exhibiting 90% adsorption efficiency after three regenerations. A deep study on equilibrium isotherms reveals a pH-dependent behavior, characterized by Langmuir and Freundlich models at pH = 5 and pH = 1, respectively. Thermodynamic studies were consistent with physicochemical adsorption for all experiments but showed a change from endothermic to exothermic behavior as the temperature increased. Interference studies of other ions commonly present in water were carried out, enabling this procedure as very selective for nitrate ions. In addition, the method was applied to real samples of seawater, showing its ability to eliminate the total nitrate content in eutrophized waters.https://www.mdpi.com/2073-4441/13/13/1757adsorptionmagnetic nanoparticlesnitratepollutant removalwater remediation |
spellingShingle | Yesica Vicente-Martínez Manuel Caravaca Antonio Soto-Meca Miguel Ángel Martín-Pereira María del Carmen García-Onsurbe Adsorption Studies on Magnetic Nanoparticles Functionalized with Silver to Remove Nitrates from Waters Water adsorption magnetic nanoparticles nitrate pollutant removal water remediation |
title | Adsorption Studies on Magnetic Nanoparticles Functionalized with Silver to Remove Nitrates from Waters |
title_full | Adsorption Studies on Magnetic Nanoparticles Functionalized with Silver to Remove Nitrates from Waters |
title_fullStr | Adsorption Studies on Magnetic Nanoparticles Functionalized with Silver to Remove Nitrates from Waters |
title_full_unstemmed | Adsorption Studies on Magnetic Nanoparticles Functionalized with Silver to Remove Nitrates from Waters |
title_short | Adsorption Studies on Magnetic Nanoparticles Functionalized with Silver to Remove Nitrates from Waters |
title_sort | adsorption studies on magnetic nanoparticles functionalized with silver to remove nitrates from waters |
topic | adsorption magnetic nanoparticles nitrate pollutant removal water remediation |
url | https://www.mdpi.com/2073-4441/13/13/1757 |
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