1,815 research outputs found
Benchtop NMR relaxometry for the follow-up of Cr(III) and Mn(II) removal by ion exchange resin.
No full textpeer reviewedWater pollution by heavy metals has become a major public health and environmental concern [1]. The removal of these metals from water is often performed by ion exchange. However, Current techniques to study ion exchange efficiency are indirect and destructive. In this research, the paramagnetic properties of Cr(III) and Mn(II) are used to monitor their removal by an ion exchange resin. Indeed, the presence of paramagnetic ions affect the Nuclear Magnetic Resonance (NMR) relaxation times T1 and T2 of water protons which can be easily measured by benchtop NMR relaxometry [2-3].
In order to study ion exchange kinetics, a NMR tube was filled with a small amount of Dowex Marathon MSC resin and 350 µL of aqueous solutions containing the paramagnetic ion of interest before being shaken by a vortex mixer. The transverse relaxation time was measured at different time intervals which allowed the monitoring of the amount of loaded metal. The same experiment was repeated with different metal concentrations to provide the adsorption isotherms.
The equilibrium isotherm behavior of Cr(III) or Mn(II) are satisfactorily described by the Langmuir model with the maximum adsorption capacity of 21.8 mg g-1 and 58.1 mg g-1 for Cr(III) and Mn(II) respectively. Experimental kinetic data fit well with the pseudo-first and pseudo-second order model.
In the future, it will be interesting to carry out a so-called NMR column experiment in order to follow the loading of adsorbent in real-time through the measurement of the NMR signal of the resin.
References
[1] Tchounwou, P. B., Yedjou, C. G., Patlolla, A. K., & Sutton, D. J., Molecular, Clinical and Environmental Toxicology. Experientia Supplementum,101, 133-164 (2012).
[2] Gossuin, Y., Hantson, A.-L., & Vuong, Q. L, Journal of Water Process Engineering, 33, 101024 (2020).
[3] Gossuin, Y., & Vuong, Q. L., Separation and Purification Technology, 202, 138-143 (2018).4933 - PDR-Gossuin - Study of heavy metal removal by NMR - Fédération Wallonie Bruxelle
Study of heavy metal removal by benchtop NMR.
No full textWater pollution by heavy metals is a major environmental concern [1]. In this context,
adsorption of metal present in wastewater by ion exchange resins or adsorbents is one of the
most used methods. However, current techniques to study the adsorption efficiency are indirect
and destructive.
In this research, the paramagnetic properties of some heavy metal present in wastewater (Cu
(II), Ni (II), Mn (II), Cr (III)) are used. Indeed, it is well known that paramagnetic ions affect
the Nuclear Magnetic Resonance (NMR) relaxation times of water protons, which can be
measured by benchtop NMR relaxometry [2-3]. Therefore, the purpose of this study is to prove
the abilities of direct and non-destructive NMR relaxometry to monitor the removal of
paramagnetic heavy metals.
In order to study the adsorption kinetics, a sample containing a small amount of resin
(Amberlite IR120) was put in contact with aqueous solutions containing the paramagnetic ion
of interest before being shaken by a vortex mixer. The transverse relaxation time (T2) was
measured at different time intervals which allowed the monitoring of the amount of adsorbed
metal. Repeating the same experiment with different metal concentrations provided the
adsorption isotherms.
The equilibrium adsorption behavior of all metal ions can be satisfactorily described by the
Langmuir model, with maximum adsorption capacity of 81.5 mg g-1
and 7.9 mg g-1
for Cu (II)
and Cr (III) respectively whereas the sorption equilibrium constant are 1 mM-1
(Cu (II)) and
0.6 mM-1
(Cr (III)). Experimental kinetic data fitted well with the pseudo-second-order kinetic
model.
The next step will be to reproduce these experiments for other resins, adsorbents and
paramagnetic ions at different magnetic fields. With our methodology, the adsorption could be
followed with very low-cost portable NMR device. In the future, it will also be interesting to
carry out a so-called NMR column experiment in order to investigate the adsorption within the
resin in real-time.
References:
[1] Tchounwou, P. B., Yedjou, C. G., Patlolla, A. K., & Sutton, D. J., Molecular, Clinical and Environmental
Toxicology. Experientia Supplementum,101, 133-164 (2012).
[2] Gossuin, Y., Hantson, A.-L., & Vuong, Q. L, Journal of Water Process Engineering, 33, 101024 (2020).
[3] Gossuin, Y., & Vuong, Q. L., Separation and Purification Technology, 202, 138-143 (2018).Study of heavy metal removal by NMR - Fédération Wallonie Bruxelle
Study of Cr(III) and Mn(II) loaded resin by benchtop nuclear magnetic resonance.
No full textpeer reviewedHeavy metals have become a major public health and environmental concern [1]. The removal of
these metals from water is often performed by ion exchange. In this context, ICP-AES spectroscopy
is currently used to study ion exchange efficiency. However, this technique is indirect and
destructive. Some heavy metal ions like Cr(III) and Mn(II) have paramagnetic properties that can
affect the Nuclear Magnetic Resonance (NMR) relaxation times T1 and T2 of water protons which
can be easily measured by benchtop NMR relaxometry [2-3]. Therefore, T1 and T2 can be used to
follow the evolution of the concentration of paramagnetic ions in solution and thereby monitor the
removal of heavy metals by a strong cation exchange resin.
Batch experiments were carried out to study the ion exchange kinetics: a sample containing a small
amount of Dowex Marathon MSC resin was put in contact with aqueous solutions containing the
paramagnetic ion of interest before being shaken by a vortex mixer (Figure 1). The transverse
relaxation time (T2) was measured at different time intervals which allowed the monitoring of the
amount of adsorbed metal. Repeating the same experiment with different metal concentrations
provided the adsorption isotherms.
The experimental kinetic data were in good agreement with the pseudo-first order kinetic model.
The equilibrium isotherms of Cr(III) and Mn(II) were described by the Langmuir and Freundlich
models.
The next step will be to reproduce these experiments with other adsorbents like activated carbon at
different magnetic fields. In the future, it will also be interesting to carry out a so-called NMR
column experiment in order to follow the loading of resin in real-time through the measurement of
the NMR signal.References : [1] Tchounwou, P. B., Yedjou, C. G., Patlolla, A. K., & Sutton, D. J., Molecular, Clinical and Environmental
Toxicology. Experientia Supplementum,101, 133-164 (2012).
[2] Gossuin, Y., Hantson, A.-L., & Vuong, Q. L, Journal of Water Process Engineering, 33, 101024 (2020).
[3] Gossuin, Y., & Vuong, Q. L., Separation and Purification Technology, 202, 138-143 (2018).4933 - PDR-Gossuin - Study of heavy metal removal by NMR - Fédération Wallonie Bruxelle
Low resolution nuclear magnetic resonance for the study of nickel (II) and manganese (II) removal by ion exchange resin.
No full textHeavy metals discharged by industrial wastewater to the environment has become a major public
health and environmental concern [1]. In this context, adsorption of metal present in wastewater
by ion exchange resins or adsorbents is one of the most used methods. However, current
techniques to study the adsorption efficiency are indirect and destructive.
In this research, the paramagnetic properties of Ni (II), Mn (II) present in wastewater are used.
Indeed, it is well known that paramagnetic ions affect the Nuclear Magnetic Resonance (NMR)
relaxation times of water protons, which can be measured by benchtop NMR relaxometry [2-3].
Therefore, the purpose of this study is to prove the abilities of direct and non-destructive NMR
relaxometry to monitor the removal of paramagnetic heavy metals.
In order to study the adsorption kinetics, a sample containing a small amount of resin (Amberlite
IR120) was put in contact with aqueous solutions containing the paramagnetic ion of interest
before being shaken by a vortex mixer. The transverse relaxation time (T2) was measured at
different time intervals which allowed the monitoring of the amount of adsorbed metal. Repeating
the same experiment with different metal concentrations provided the adsorption isotherms.
The equilibrium adsorption behavior of all metal ions can be satisfactorily described by the
Langmuir model, with maximum adsorption capacity of 84.1 mg g-1 and 50.3 mg g-1
for Ni (II) and
Mn (II) respectively whereas the sorption equilibrium constant are 1.55 L mg-1
(Ni (II)) and 40.2 L
mg-1
(Mn (II)). Experimental kinetic data fitted well with the pseudo-second-order kinetic model.
The next step will be to reproduce these experiments for other adsorbents and paramagnetic ions
at different magnetic fields. With this methodology, the adsorption could be followed with low-cost
portable NMR device. In the future, it will also be interesting to carry out a so-called NMR column
experiment in order to investigate the adsorption within the resin in real-time.
References
[1] Tchounwou, P. B., Yedjou, C. G., Patlolla, A. K., & Sutton, D. J., Molecular, Clinical and Environmental
Toxicology. Experientia Supplementum,101, 133-164 (2012).
[2] Gossuin, Y., Hantson, A.-L., & Vuong, Q. L, Journal of Water Process Engineering, 33, 101024 (2020).
[3] Gossuin, Y., & Vuong, Q. L., Separation and Purification Technology, 202, 138-143 (2018).Study of heavy metal removal by NMR - Fédération Wallonie Bruxelle
Study of heavy metal loaded resins by benchtop NMR.
No full textHeavy metals discharged by industrial wastewater to the environment has become a major public health and environmental concern [1]. For example, heavy metals ions such as Ni (II) and Cu (II) are known to be toxic and must be removed from wastewater. However, Ni (II) and Cu (II) ions also have paramagnetic properties which previously allowed the use of Magnetic Resonance Imaging (MRI) and Nuclear Magnetic Resonance (NMR) relaxometry to follow their migration and their adsorption on different media [2-3]. The purpose of this study is to monitor the removal of Ni (II) and Cu (II) from water by amberlite IR120 with T1 and T2 relaxometry. In order to obtain the adsorption isotherms, different samples containing the same amount of Amberlite IR120 resin was put in contact with aqueous solutions containing Ni (II) or Cu (II) ions at different concentrations, before being shaken by a vortex mixer. Once the equilibrium reached, the longitudinal and transversal relaxation time (T1, T2) of the solution was measured which allowed the determination of the amount of adsorbed metal. Study of the loaded resin was afterwards carried out using a larger amount of resin which was dried and rehydrated before being analyzed. The equilibrium adsorption behavior of Ni (II) or Cu (II) can be satisfactorily described by the Langmuir model, with maximum adsorption capacity of 81.5 mg g-1 and 78.3 mg g-1 for Cu (II) and Ni (II) respectively whereas the sorption equilibrium constants are 0.98 mM-1 (Cu (II)) and 1.8 L mM-1 (Ni (II)). The longitudinal and transverse relaxation of the wet resin are shown to be biexponential. The relaxation rate of the fast relaxing water fraction of the wet resin can be correlated with metal contents obtained by Atomic Emission Spectroscopy (ICP-AES). The next step will be to reproduce these experiments for other adsorbents and paramagnetic ions at different magnetic fields. With this methodology, the adsorption could be followed with low-cost portable NMR device. In the future, it will also be interesting to carry out a so-called NMR column experiment in order to investigate the adsorption within the resin in real-time.
References: [1] Tchounwou, P. B., Yedjou, C. G., Patlolla, A. K., & Sutton, D. J., Molecular, Clinical and Environmental Toxicology. Experientia Supplementum, 2021, 101, 133-164. [2] Gossuin, Y., Hantson, A.-L., & Vuong, Q. L, Journal of Water Process Engineering, 2020, 33, 101024. [3] Gossuin, Y., & Vuong, Q. L., Separation and Purification Technology, 2018, 202, 138-143.Study of heavy metal removal by NMR - Fédération Wallonie Bruxelle
Yves-Heng Lim
No full textYves-Heng Lim est enseignant-chercheur au Département d’Etudes de Sécurité et de Criminologie de l’Université Macquarie, Sydney. Il est l’auteur de China’s Naval Power: An Offensive Realist Approach (Ashgate, 2014). Yves-Heng Lim is a lecturer at the Department of Security Studies and Criminology, Macquarie University. He is the author of China’s Naval Power: An Offensive Realist Approach (Ashgate, 2014)
The question of empire today
No full textY.C. Zarka, tomando como referencia la política exterior de Estados Unidos, presenta una reflexión en perspectiva histórica, política y filosófica sobre la idea contemporánea de imperio. Los modelos del imperio romano y del imperio colonial han sido abandonados. El imperialismo contemporáneo impone su hegemonía por las vías económica y cultural. Partiendo de la dialéctica imperio-imperialismo, desde los conceptos de soberanía y democracia, el autor muestra las contradicciones internas y externas de lo que denomina repúblicas imperiales. Desde la primera perspectiva, la hegemonía imperial puede ser interpretada al mismo tiempo como la expresión y la crisis de la soberanía. Desde la segunda, la contradicción se encuentra en la justificación de una política internacional intervencionista en nombre de las ideas de libertad, república y democracia.Y.C. Zarka, has taking the foreign policy of the United States as a reference, presenting a reflection on the contemporary idea of empire in historical, political and philosophical perspective. The models of the Roman Empire and the colonial empire have been left behind. The contemporary imperialism enforces its hegemony by economy and culture. Due the empire-imperialism dialectic, the author shows the internal and external contradictions of what he names "imperial republics". For instance: the imperial hegemony can be interpreted as expression and crisis of the idea sovereignty; the interventionist international policy is justified on behalf of freedom, republic and democracy ideas.Publicad
Presentazione dell’edizione italiana di storia della Sicilia da Odisseo ai giorni nostri di Jean-Yves Frétigné
No full textPublished for the first time in 2009, for the Fayard types, and re-edited in 2018 in a "pocket" format, this History of Sicily by Jean-Yves Frétigné, with the subtitle from Odysseus to the present day, presented to the French public as an easy consultation, a "Compagnon de voyage" destined to have an excellent editorial success with over 8,000 copies sold.The Italian translation presented here does not have the presumption of concurring with the monumental works of the history of Sicily which constitute an essential reference by the same Author, as the rich bibliography in the appendix to the volume clearly testifies. Rather, it intends to offer, in just over 400 pages, the “external” look on Sicily of a French historian, as Finley, Mack Smith, Duggan or Norwich have done in the past
Benchtop NMR relaxometry to monitor Ni (II) removal by resin and activated charcoal
No full textpeer reviewedWater pollution by heavy metals is a major environmental concern. In this context, removal of heavy metal from wastewater by ion exchange resins or adsorbents is often necessary. However, current techniques to study adsorption efficiency are indirect and sometimes destructive. Some heavy metal ions like Ni(II) have paramagnetic properties that can affect the NMR relaxation times T1 and T2 of water protons, which can be measured by benchtop NMR relaxometry. Therefore, T1 and T2 can be used to monitor the removal of paramagnetic heavy metals by a sorbent. In this work, the removal of Ni(II) by Dowex Marathon MSC resin and commercial activated charcoal was studied.
Batch experiments were carried out to study the ion exchange/adsorption isotherms: a sample containing 10 mg of resin or 50 mg of activated charcoal was put in contact with aqueous solutions containing different concentrations of Ni(II), before being shaken by a vortex mixer. Once the equilibrium reached, T1 of the solution was measured which allowed the determination of the amount of adsorbed metal. The study of the loaded sorbent was also carried out.
The equilibrium isotherms of Ni(II) were satisfactorily described by the Langmuir model for both studied sorbent. The longitudinal and transverse relaxation of the wet resin is shown to be biexponential. The relaxation rates of the fast relaxing water fraction of the Ni(II) loaded wet resin can be correlated with the metal content obtained independently by AES after acidic digestion of the samples. Loaded activated charcoal, due to its important microporosity but also because of a partial desorption of Ni(II) ions, exhibits a more complex relaxation behavior.
Based on these results, a column experiment will be set up inside the NMR coil in order to follow the loading of the sorbent in real-time through the evolution of the NMR signal.4933 - PDR-Gossuin - Study of heavy metal removal by NMR - Fédération Wallonie Bruxelle
Comparison of the thickness of the calvarium between young grey (Halichoerus grypus) and harp (Pagophilus groenlandicus) seals = Comparaison de l'épaisseur de la calotte crânienne entre les jeunes phoques gris (Halichoerus grypus) et les jeunes phoques du Groenland (Pagophilus groenlandicus)
No full textCharles Caraguel, Pierre-Yves Daoust and Fiep de Bie.; 1 online resource (ii, 6 pages); 1919-5044; Distributed by the Government of Canada Depository Services Program (Weekly checklist 2013-35).; Includes bibliographical references.; Mode of access: Internet.; Issued by: Fisheries and Oceans, Quebec Region.; Co-author Pierre-Yves Daoust is a member of faculty at University of Prince Edward Island.; Research document (Canadian Science Advisory Secretariat : Online) ; 2012/172
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