Extractant Immobilization in Alginate Capsules (Matrix- and Mononuclear-Type): Application to Pb(II) Sorption from HCl Solutions - IMT Mines Alès Accéder directement au contenu
Article Dans Une Revue Materials Année : 2017

Extractant Immobilization in Alginate Capsules (Matrix- and Mononuclear-Type): Application to Pb(II) Sorption from HCl Solutions

Résumé

The decontamination of dilute industrial effluents is a critical challenge for decreasing the environmental impact of mining and metallurgical activities. As an alternative to conventional processes, new extractant impregnated resins (EIRs) have been synthesized by the immobilization of Cyanex 301 and Cyanex 302 in alginate capsules using two different procedures (matrix-type immobilization vs. mononuclear encapsulation). These materials have been tested for Pb(II) sorption from acidic solutions. The Langmuir equation fitted well the sorption isotherms and the maximum sorption capacities vary between 24 and 80 mgg(-1) at pH 1, depending on the type and loading of the extractant in the EIR. Uptake kinetics were controlled by the resistance to intraparticle diffusion; though both the Crank equation (intraparticle diffusion) and pseudo-second order rate equation equally fitted uptake profiles. The amount of extractant immobilized in mononuclear capsules is lower than in matrix-type beads; this leads to lower sorption capacities but slightly better mass transfer properties. The balance between the advantages and drawbacks of the different systems makes more promising matrix-type capsules. The desorption of Pb(II) is possible using 1 M HNO3 solutions: metal ions were completely desorbed. However, the probable oxidation of the extractants (conversion to oxidized forms more sensitive to pH) reduces the sorption efficiency when they are re-used.
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Dates et versions

hal-02892700 , version 1 (09-07-2020)

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Janette Alba, Ricardo Navarro, Imelda Saucedo, Thierry Vincent, Eric Guibal. Extractant Immobilization in Alginate Capsules (Matrix- and Mononuclear-Type): Application to Pb(II) Sorption from HCl Solutions. Materials, 2017, 10 (6), pp.634. ⟨10.3390/ma10060634⟩. ⟨hal-02892700⟩
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