Search

The characterization of wastes constituted by LED lamps at the end of their lives is currently a concern of researchers and environmental managers not only because of the large volume will be generated by such wastes, but also to identify appropriate strategies for their reuse as well as their recyclability. This research describes the different steps involved in the characterization of LED lamps at the end of their lives such as, testing the functionality of the whole lamps, as well as modules and the LED components of the non-functional lamps. The results revealed that about 30.8 % of the wasted LED lamps are still working and could be reused in the social and solidarity economy or remarketed if economically viable. On the other hand, functionality test of the non-functional lamps showed that 56.5 % of the LED modules and 75% of the LED chips are still functional. Our investigations revealed that, repairing the non-functional lamps or reusing their functional components is challenging and therefore, their recycling is highly recommended.

International audience; We report herein the synthesis of zwitterionic sulfobetaine (SB) and dimethylamine oxide (AO) detergents whose alkyl chain is made of either a perfluorohexyl (F6H3) or a perfluoropentyl (F5H5) group linked to a hydrogenated spacer arm. In aqueous solution, the critical micellar concentrations (CMCs) measured by surface tensiometry (SFT) and isothermal titration calorimetry (ITC) were found in the millimolar range (1.3-2.4 mM). The morphologies of the aggregates were evaluated by dynamic light scattering (DLS), analytical ultracentrifugation (AUC), small-angle X-ray scattering (SAXS), and transmission electron microscopy (TEM), demonstrating that the two perfluoropentyl derivatives formed small micelles less than 10 nm in diameter, whereas the perfluorohexyl derivatives formed larger and more heterogeneous micelles. The two SB detergents were able to solubilize synthetic lipid vesicles in a few hours; by contrast, the perfluoropentyl AO induced much faster solubilization, whereas the perfluorohexyl AO did not show any solubilization. All detergents were tested for their abilities to stabilize three membrane proteins, namely, bacteriorhodopsin (bR), the Bacillus subtilis ABC transporter BmrA, and the Streptococcus pneumoniae enzyme SpNOX. The SB detergents outperformed the AO derivatives as well as their hydrogenated analogs in stabilizing these proteins. Among the four new compounds, F5H5SB combines many desirable properties for membrane-protein study, as it is a powerful yet gentle detergent.

International audience; Two new surfactants, F5OM and F5DM, were designed as partially fluorinated analogues of n-dodecyl-β-D-maltoside (DDM). The micellization properties and the morphologies of the aggregates formed by the two surfactants in water and phosphate buffer were evaluated by NMR spectroscopy, surface tension measurement, isothermal titration calorimetry, dynamic light scattering, small-angle X-ray scattering, and analytical ultracentrifugation. As expected, the critical micellar concentration (cmc) was found to decrease with chain length of the fluorinated tail from 2.1-2.5 mM for F5OM to 0.3-0.5 mM for F5DM, and micellization was mainly entropy-driven at 25 °C. Close to their respective cmc, the micelle sizes were similar for both surfactants, that is, 7 and 13 nm for F5OM and F5DM, respectively, and both increased with concentration forming 4 nm diameter rods with maximum dimensions of 50 and 70 nm, respectively, at a surfactant concentration of ∼30 mM. The surfactants were found to readily solubilize lipid vesicles and extract membrane proteins directly from Escherichia coli membranes. They were found more efficient than the commercial fluorinated detergent F6H2OM over a broad range of concentrations (1-10 mM) and even better than DDM at low concentrations (1-5 mM). When transferred into the two new surfactants, the thermal stability of the proteins bacteriorhodopsin (bR) and FhuA was higher than in the presence of their solubilization detergents and similar to that in DDM; furthermore, bR was stable over several months. The membrane enzymes SpNOX and BmrA were not as active as in DDM micelles but similarly active as in F6OM. Together, these findings indicate both extracting and stabilizing properties of the new maltose-based fluorinated surfactants, making them promising tools in MP applications.

International audience; Two extractants, N,N′-((octylazanediyl)bis(ethane-2,1-diyl))dioctanamide (LI) and N,N′-((octylazanediyl)bis(ethane-2,1-diyl))di-2-methylheptanamide (LII), have been synthesised in two steps starting from diethylenetriamine and involving a peptide coupling step. The efficiency and selectivity of the extractants in dodecane/octanol (95/5 v/v) toward the extraction of uranium from sulfate media have been investigated showing that the uranium extraction from sulfuric acid is more efficient at a low H2SO4 concentrations. Slope analysis method revealed 2:1 extractant/metal ratio, which is in accordance with NMR titration as well as DFT calculations. The extractants are found to be selective toward uranium over competitive cations present in a simulated leach solution. Finally, a stripping step has been performed and given rise to a successful quantitative recovery of uranium

A cleaner and eco-friendly method was developed for the preparation of tetrakis(aminomethyl)calix-[4]-resorcinarene via a synthetic pathway of five steps starting from methylresorcinol. This alternative methodology is firstly based on avoiding the use of CH2BrCl, which is a non-eco-friendly substance with high ozone depletion potential, and on replacing it by CH2Cl2 as a readily available reagent with much less dangerous effects. Secondly, this method engages acetone or CH2Cl2 as the solvent of the bromination step in the place of the very toxic CCl4, leading to tetrakis(bromomethyl)calix-[4]-resorcinarene. The brominated intermediate has been reacted with sodium azide in acetone instead of the high-boiling solvent DMSO to produce tetrakis(azidomethyl) calix-[4]-resorcinarene without the need of tedious purification. Lastly, this work reports an efficient hydrogenation method of the versatile azido adduct employing Pt/C (5%) as the catalyst for the preparation of the amino cavitand as an alternative route with high atom economy that can replace the classical methods used currently.

International audience; The selective extraction of uranium by N-octylcalix[4]azacrown (NOCAC) and N-ethylhexylcalix[4]azacrown (NEHCAC) was investigated. The ligands were synthesised in three steps through the functionalisation of t-butyl calix[4]arene at the distal-1,3-positions of the lower rim with ethyl acetate groups followed by cyclisation with (imino)bis(ethane-2,1-diyl)diamide. A detailed investigation on the effect of various parameters, such as the aqueous phase acidity (sulfuric acid), the ionic strength, and ligand concentration, on the extraction of uranium(VI) has been conducted. The effect of the H2SO4 concentration has been studied from 0.02 to 3 M. Preliminary studies carried out on NOCAC in dodecane/octanol diluents showed that the uranium extraction from sulfuric acid is more efficient at a low H2SO4 concentrations. The stoichiometry of complexation was estimated from the slope method, NMR titration, and electrospray ionisation-mass spectrometry analysis. Both ligands were found to be highly selective for uranium(VI) over other competitive cations present in a simulated leach solution containing seven competitive cations. The successful recovery of the uranium from the organic phase has been performed thanks to stripping steps involving ammonium oxalate, ammonium carbonate, and sodium carbonate as stripping agents.

Two calix(4)resorcinarene based cavitands, one that contains four triazole units, calix(4)resorcinarene-tetra(hexyltriazole) CR4-Tz LI , and another that contains four triazole diglycolamide units, calix(4)resorcinarene-tetra(didecyldiglycolamidetriazole) CR4-Tz-DDDGA LII , were synthesized and fully characterized by IR, NMR, and MS. The efficiency of the two cavitands were compared toward the extraction of 7 lanthanides (Ce(III), Nd(III), Sm(III), Gd(III), Dy(III), Er(III), Yb(III)) in chloroform from 5 M HNO 3 . The extraction study showed that LI , which contains only the triazole units, is unable to extract any of the targeted metals. The effects of the organization and diluents on the distribution coefficients and the selectivity of LII were also studied toward the same lanthanide series at the same acidity. The obtained results showed that the cavitand is selective toward heavy lanthanides irrespective of the diluents. The extraction and stripping experiments of the 7 Ln(III) and the separation of Nd and Dy from a Fe-B-Nd-Dy leaching solution were performed.

Solvent extraction of lanthanides Ln(iii) (La, Eu and Yb) with resorcin[4]arene cavitand-triazole-DODGA (CR4-TZ-DODGA) and t-butylcalix[4]arene-triazole-DODGA (C4-TZ-DODGA) has been studied in a room temperature ionic liquid (RTIL), N-octyl-N-ethylpiperidinium bis(trifluoromethylsulfonyl)imide ([EOPip]NTf2). The two macrocyclic platforms were functionalized with four diglycolamide (DGA) moieties thanks to a click reaction and fully characterized by NMR and MS analysis. The effects of acidity as well as the concentration of the ligands were investigated on the extraction and separation properties. The parameters of the extraction processes were determined by the slope method and thermodynamic studies. For both ligands, the extraction efficiency changes along the lanthanoid series with selectivity toward Yb(iii) in regard to La(iii) and Eu(iii). The selective extraction and recovery of lanthanides from a simulated leaching solution of a Nd/Fe/B/Dy magnet has also been investigated.

International audience; A C-methylcalix(4)methylresorcinarene–DODGA ligand, derived from calix[4]methylresorcinarene functionalized with four diglycolamide (DGA) binding units, was synthesized and characterized by NMR and MS. The ligand was investigated with respect to the extraction of rare earth elements (REEs) from nitric acid solution. High sensitivity was observed, particularly toward heavy rare earth elements. The acidity effects, as well as the concentration of the extractant, were evaluated with regard to the extraction and separation efficiencies. The results showed that the distribution coefficient values increase with an increase in nitric acid concentration in the range from 0.1 to 5 mol L−1. A slope analysis method and spectrophotometric titrations showed clear complexation of the REEs with the ligand. An extraction mechanism is proposed from the estimation of the thermodynamic parameters (ΔH, ΔS, and ΔG). The extraction and stripping of REEs from a simulated leaching solution of a Nd/Fe/B/Dy magnet have been studied.

International audience; Click chemistry, which relies on the efficiency of the copper (I)-catalyzed azide-alkyne cycloaddition, was used to link four diglycolamide (DGA) moieties to a resorcinarene platform leading to a specific tetra-DGA-resorcinarene ligand (c-methylcalix(4)methylresorcinarene-4-triazole-dioctyldiglycolamide denoted CR4-Tz-DODGA). The extraction ability of this ligand was studied in a mixture of toluene/iso-octanol (90/10, v/v) toward rare earth elements (REE) at different nitric acid concentrations, ranging from 1 to 5 M. The results show the efficient extractability of and selectivity towards heavy REEs. The stoichiometry of the extraction was established by the slope analysis method and an extraction mechanism was proposed based on estimates of the thermodynamic parameters. From the extraction behavior of the tetra-DGA-resorcinarene ligand, we present the possibility for the extraction and separation of dysprosium from used permanent magnets.