A recycling process for lamp phosphor waste has been developed based on the selective dissolution and revalorization of the valuable red lamp phosphor Y2O3:Eu3+ in the functionalized ionic liquid [Hbet][Tf2N].

A new recycling process was developed to recover rare earths from roasted NdFeB magnets using the thermomorphic and acidic properties of the ionic liquid [Hbet][Tf2N] to achieve a combined leaching/extraction system.

Hydrophobic (water-immiscible) ionic liquids (ILs) are frequently used as organic phase in solvent extraction studies. These biphasic IL/water extraction systems often also contain metal salts or mineral acids, which can significantly affect the IL trough (un)wanted anion exchange and changes in the solubility of IL in the aqueous phase. In the case of thermomorphic systems, variations in the cloud point temperature are also observed. All these effects have important repercussions on the choice of IL, suitable for a certain extraction system. In this paper, a complete overview of the implications of metal salts on biphasic IL/water systems is given. Using the Hofmeister series as a starting point, a range of intuitive prediction models are introduced, supported by experimental evidence for several hydrophobic ILs, relevant to solvent extraction. Particular emphasis is placed on the IL betainium bis(trifluoromethylsulfonyl)imide [Hbet][Tf2N]. The aim of this work is to provide a comprehensive interpretation of the observed effects of metal salts, so that it can be used to predict the effect on any given biphasic IL/water system instead of relying on case-by-case reports. These prediction tools for the impact of metal salts can be useful to optimize IL synthesis procedures, extraction systems and thermomorphic properties. Some new insights are also provided for the rational design of ILs with UCST or LCST behavior based on the choice of IL anion.

Magnetic (Fe3O4) and nonmagnetic (SiO2 and TiO2) nanoparticles were decorated on their surface with N-[(3-trimethoxysilyl)propyl]ethylenediamine triacetic acid (TMS-EDTA). The aim was to investigate the influence of the substrate on the behavior of these immobilized metal coordinating groups. The nanoparticles functionalized with TMS-EDTA were used for the adsorption and separation of trivalent rare-earth ions from aqueous solutions. The general adsorption capacity of the nanoparticles was very high (100 to 400 mg/g) due to their large surface area. The heavy rare-earth ions are known to have a higher affinity for the coordinating groups than the light rare-earth ions but an additional difference in selectivity was observed between the different nanoparticles. The separation of pairs of rare-earth ions was found to be dependent on the substrate, namely the density of EDTA groups on the surface. The observation that sterical hindrance (or crowding) of immobilized ligands influences the selectivity could provide a new tool for the fine-tuning of the coordination ability of traditional chelating ligands.

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New sulfonic acid functionalized ionic liquids (SAFILs) with bis(trifluoromethylsulfonyl)imide anions were synthesized. These ionic liquids are strong Brønsted acids and can solubilize metal oxides. Water-immiscible SAFILs were used as organic phases in solvent extraction studies.

Core-shell Fe 3 O 4 @SiO 2 nanoparticles were prepared with a modified Stöber method and functionalized with N- [(3-trimethoxysilyl)propyl]ethylenediamine triacetic acid (TMS-EDTA).The synthesis was optimized to make core-shell nanoparticles with homogeneous and thin SiO 2 shells (4.8 ± 0.5 nm) around highly superparamagnetic Fe 3 O 4 cores (14.5 ± 3.0 nm). The coreshell Fe 3 O 4 @SiO 2 (TMS-EDTA) nanoparticles were then used for the extraction and separation of rare-earth ions. By comparing them with previously published results for Fe 3 O 4 (TMS-EDTA) and SiO 2 (TMS-EDTA) nanoparticles, it was clear that the core-shell nanoparticles combine the advantage of magnetic retrieval observed for Fe 3 O 4 (TMS-EDTA) nanoparticles, with the higher selectivity observed for SiO 2 (TMS-EDTA). The advantages of the SiO 2 shell include a lower specific weight and a larger grafting density compared to Fe 3 O 4 surfaces, but also the improved resistance to acidic environments required for the stripping of rare-earth ions.

Antimony has become an increasingly critical element in recent years, due to a surge in industrial demand and the Chinese domination of primary production. Antimony is produced from stibnite ore (Sb 2 O 3) which is processed into antimony metal and antimony oxide (Sb 2 O 3). The industrial importance of antimony is mainly derived from its use as flame retardant in plastics, coatings, and electronics, but also as decolourizing agent in glass, alloys in lead-acid batteries, and catalysts for the production of PET polymers. In 2014, the European Commission highlighted antimony in its critical raw materials report, as the element with the largest expected supply-demand gap over the period 2015-2020. This has sparked efforts to find secondary sources of antimony either through the recycling of end-of-life products or by recovering antimony from industrial process residues. Valuable residues are obtained by processing of gold, copper, and lead ores with high contents of antimony. Most of these residues are currently discarded or stockpiled, causing environmental concerns. There is a clear need to move to a more circular economy, where waste is considered as a resource and zero-waste valorization schemes become the norm, especially for rare elements such as antimony. This paper gives a critical overview of the existing attempts to recover antimony from secondary sources. The paper also discusses the possibility of waste valorization schemes to guarantee a more sustainable life cycle for antimony.