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Recherche transversale
(titres de publication, de périodique et noms de colloque inclus)
2021-08-25 - Colloque/Présentation - poster - Anglais - page(s)

Bernardi Marie , Gossuin Yves , "Study of heavy metal removal by benchtop NMR." in ISMAR-APNMR, Virtual event, 2021

  • Codes CREF : Physique du spin (genre RMN) (DI1234)
  • Unités de recherche UMONS : Physique biomédicale (M104)
  • Instituts UMONS : Institut de Recherche en Science et Ingénierie des Matériaux (Matériaux), Institut des Sciences et Technologies de la Santé (Santé)
Texte intégral :

Abstract(s) :

(Anglais) Water 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).

Identifiants :
  • FNRS : T.0113.20