The use of biomass for adsorption of rare earth elements (REEs) has been the subject of many recent investigations. However, REE adsorption by bioengineered systems has been scarcely documented, and ...rarely tested with complex natural feedstocks. Herein, we engineered E. coli cells for enhanced cell surface-mediated extraction of REEs by functionalizing the OmpA protein with 16 copies of a lanthanide binding tag (LBT). Through biosorption experiments conducted with leachates from metal-mine tailings and rare earth deposits, we show that functionalization of the cell surface with LBT yielded several notable advantages over the nonengineered control. First, the efficiency of REE adsorption from all leachates was enhanced as indicated by a 2–10-fold increase in distribution coefficients for individual REEs. Second, the relative affinity of the cell surface for REEs was increased over all non-REEs except Cu. Third, LBT-display systematically enhanced the affinity of the cell surface for REEs as a function of decreasing atomic radius, providing a means to separate high value heavy REEs from more common light REEs. Together, our results demonstrate that REE biosorption of high efficiency and selectivity from low-grade feedstocks can be achieved by engineering the native bacterial surface.
The current uncertainty in the global supply of rare earth elements (REEs) necessitates the development of novel extraction technologies that utilize a variety of REE source materials. Herein, we ...examined the techno-economic performance of integrating a biosorption approach into a large-scale process for producing salable total rare earth oxides (TREOs) from various feedstocks. An airlift bioreactor is proposed to carry out a biosorption process mediated by bioengineered rare earth-adsorbing bacteria. Techno-economic assessments were compared for three distinctive categories of REE feedstocks requiring different pre-processing steps. Key parameters identified that affect profitability include REE concentration, composition of the feedstock, and costs of feedstock pretreatment and waste management. Among the 11 specific feedstocks investigated, coal ash from the Appalachian Basin was projected to be the most profitable, largely due to its high-value REE content. Its cost breakdown includes pre-processing (leaching primarily, 77.1%), biosorption (19.4%), and oxalic acid precipitation and TREO roasting (3.5%). Surprisingly, biosorption from the high-grade Bull Hill REE ore is less profitable due to high material cost and low production revenue. Overall, our results confirmed that the application of biosorption to low-grade feedstocks for REE recovery is economically viable.
Magnesium isotopic compositions are reported for twenty‐four international geological reference materials including igneous, metamorphic and sedimentary rocks, as well as phlogopite and serpentine ...minerals. The long‐term reproducibility of Mg isotopic determination, based on 4‐year analyses of olivine and seawater samples, was ≤ 0.07‰ (2s) for δ26Mg and ≤ 0.05‰ (2s) for δ25Mg. Accuracy was tested by analysis of synthetic reference materials down to the quoted long‐term reproducibility. This comprehensive dataset, plus seawater data produced in the same laboratory, serves as a reference for quality assurance and inter‐laboratory comparison of high‐precision Mg isotopic data.
Les compositions isotopiques du magnésium sont fournies pour vingt‐quatre matériaux géologiques de référence internationaux, comprenant des roches ignées, métamorphiques et sédimentaires, ainsi qu'une phlogopite et des serpentines. La reproductibilité à long terme de la détermination isotopique du Mg, basée des analyses sur quatre ans d’échantillons d'olivine et d'eau de mer, était ≤ 0.07% (2s) pour δ26Mg et ≤ 0.05% (2s) pour δ25Mg. La précision a été testée par l'analyse de matériaux de référence synthétiques jusqu’à la reproductibilité à long terme indiquée. Cette base de données complète, ainsi que des données d'eau de mer produites dans le même laboratoire, servent de référence pour l'assurance qualité et la comparaison inter‐laboratoires de haute précision des données isotopiques du Mg.
We surveyed 106 patients with schizophrenia who were being treated with either oral clozapine or oral aripiprazole. For each patient, the plasma level of the medication was measured using i) a venous ...blood sample and a conventional lab-based assay and ii) a novel point of care assay that used a capillary blood sample taken with a fingerprick. Immediately after providing the two samples, participants completed a brief questionnaire. We also surveyed 10 members of staff who were directly involved in the care of these patients.
98% of patients found the capillary point-of-care approach acceptable, and 85% preferred it to the conventional venous blood procedure. 78% of patients said it was useful to have access to the result at the point of care (as opposed to at a later date), and 90% felt that POC testing improved clinical care. 83% said that the POC test made them feel more involved in their treatment. 100% of staff said their experience with the POC test was good, that it was easier than venous collection, and that it was very useful to receive the medication level while the patient was still in the clinic.
•POC test for antipsychotic medication levels was highly acceptable.•Most preferring it to conventional venous blood sampling.•Easier to introduce regular monitoring of antipsychotic medication levels.•Could improve the safety and effectiveness of all antipsychotic medications.•The acceptability of POC testing to patients is likely to make monitoring easier.
The warm climate of Bermuda today is modulated by the nearby presence of the Gulf Stream current. However, iceberg scours in the Florida Strait and the presence of ice‐rafted debris in Bermuda Rise ...sediments indicate that, during the last deglaciation, icebergs discharged from the Laurentide Ice Sheet traveled as far south as subtropical latitudes. We present evidence that an event of similar magnitude affected the subtropics during the Last Interglacial, potentially due to melting of the Greenland Ice Sheet. Using the clumped isotope paleothermometer, we found temperatures ~10°C colder and seawater δ18O values ~2‰ lower than modern in Last Interglacial Cittarium pica shells from Grape Bay, Bermuda. In contrast, Last Interglacial shells from Rocky Bay, Bermuda, record temperatures only slightly colder and seawater δ18O values similar to modern, likely representing more typical Last Interglacial conditions in Bermuda outside of a meltwater event. The significantly colder ocean temperatures observed in Grape Bay samples illustrate the extreme sensitivity of Bermudian climate to broad‐scale ocean circulation changes. They indicate routine meltwater transport in the North Atlantic to near‐equatorial latitudes, which would likely have resulted in disruption of the Atlantic Meridional Overturning Circulation. These data demonstrate that future melting of the Greenland Ice Sheet, a potential source of the Last Interglacial meltwater event, could have dramatic climate effects outside of the high latitudes.
Key Points
We used the clumped isotope thermometer to measure temperature and seawater δ18O in Bermuda during the Last Interglacial
At one locality we found cold temperatures and negative seawater δ18O values indicative of meltwater reaching subtropical latitudes
The source of this meltwater may have been the Greenland Ice Sheet, which is sensitive to future global warming
Critical materials (CMs) are a group of elements that have been determined to be important for the modern economy, but which may face current or potential supply limitations. Some examples of metals ...that have received the CM designation include the rare earth elements, indium, gallium, and lithium. The last decade has seen a major push for the development of new and improved technologies for the recovery and purification of CMs from various traditional and non-traditional resources in an effort to diversify supply. Solid-phase extraction (SPE) is one broad category of these experimental extraction technologies. SPE involves the application of a solid material to preferentially retain in the solid phase one or more specific components of an aqueous solution, leaving the other components behind in the aqueous phase. A wide range of different sorbents has been used for SPE, and many offer significant potential advantages, including low cost, low environmental impact, and high customizability. Hierarchically porous silica monoliths are one example of a cutting-edge sorbent that provides a durable, high surface area foundation that can be functionalized with a variety of targeted ligands for the selective extraction of specific CMs. Despite impressive recent advances in SPE, there remain areas for improvement that are common across the discipline. To demonstrate the practical viability of these innovative CM recovery systems, future SPE studies would benefit from devoting additional focus to the scalability of their material, as well as from focusing on real-world feedstocks and conducting techno-economic analyses and environmental impact studies.
Solid-phase extraction offers numerous advantages for critical materials recovery, and research in the field would benefit from increased focus on environmental impact, techno-economic assessments, and process scalability with real-world resources.
Rare earth elements (REEs) are an emerging pollutant whose increasing use in various technological applications causes increasing risk of environmental contamination. Electronic waste (E-waste) could ...be one major source of REE pollution, as E-waste typically contains elevated REE concentrations and is often handled in unsafe and environmentally hazardous ways. Here, a series of leaching assays revealed that <1% of REEs available in a representative E-waste were released except at acidic conditions (pH 2) rarely observed in nature. If REEs are leached from E-waste, the extent of their spread in the environment will depend, in large part, on their mobility through porous media. Measurements of REE transport through saturated sand demonstrated extremely limited mobility except at acidic conditions (pH 2), though significant REE retention by the substrate still occurs at this low pH. Similar experiments in a natural soil found REE mobility to be even lower in that substrate, with complete REE retention even after the passage of up to 215 pore volumes of a 500 ppb REE solution. Aqueous REEs are therefore not expected to be highly mobile in the environment. The presence of natural or anthropogenic nanoparticles may affect REE behavior during leaching and/or transport. Measurements indicated that silica nanoparticles can increase the concentration of fluid-mobile REEs during E-waste leaching, but both plastic and silica nanoparticles have a negligible effect on REE transport. Ultimately, the experiments and analysis presented here suggest that the threat of REE pollution from E-waste is minimal except at specific sites with unusual environmental conditions.
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•REE leaching from E-waste is unlikely to present a broad environmental hazard.•REE transport in sand and soil is minimal at a range of environmental conditions.•The presence of nanoparticles does not increase REE mobility in porous media.
A detailed study on petrology and mineral chemistry of 32 mantle xenoliths has been conducted to decipher the physical and chemical characteristics of the lithosphere beneath NE Iran. Spinel ...lherzolite, the most abundant xenolith type, is made up of olivine, orthopyroxene, clinopyroxene, and spinel. Clinopyroxenes in the spinel lherzolites display a primitive mantle-like composition, typical of non-cratonic peridotites. Pyroxenite, another major xenolith type, shows equilibrated textures and highly variable compositions including olivine websterite, websterite and clinopyroxenite. These pyroxenites, together with an equigranular dunite, delineate a clear metasomatic trend, characterized by systematic Mg#, Cr#, Al2O3, and TiO2 variations in the constituent minerals, coupled with light rare earth element enrichment and high field strength element depletion in clinopyroxene. The pyroxenites are therefore suggested to have formed by the interaction between garnet-bearing peridotites within the lithospheric mantle and melts from a stagnant slab within the asthenosphere. The lithospheric mantle may have undergone multiple stages of partial melting. The earliest stage, evidenced by the equigranular dunite, resulted in significant NiO depletion in olivine, low Al2O3 and TiO2 coupled with high Mg# and Cr# in clinopyroxene, and high Cr# in spinel. The second stage occurred more widely and gave rise to the large ion lithophile element depletion in clinopyroxenes of all rock types. The extent of melting is lower in the spinel lherzolites than that in the pyroxenites, implying that the partial melting was not caused by decompression and thus most likely related to Tethyan subduction. A third and more recent melting stage, responsible for the spongy texture in some clinopyroxenes, is attributed to the extensional tectonic regime that started in the middle Miocene in the region. Temperature estimates show that both the spinel lherzolites and pyroxenites equilibrated at ~900–1000°C. Based on our new data and published data we propose the lithospheric structure beneath NE Iran. The xenolith-defined geotherm appears to be hotter than that typical in cratonic and oceanic settings, but colder than that suggested by seismic tomographic modeling for the entire Iranian Plateau. This difference is probably due to the widespread occurrence of pyroxenites within the lithospheric mantle, which we argue could have played a significant role in causing not only the seismic and gravitational anomalies but also late Cenozoic volcanism on the Iranian Plateau.
•Primitive mantle-like composition of the upper lithospheric mantle beneath NE Iran;•Subduction-related mantle metasomatism contributing to the genesis of the pyroxenites;•NE Iranian lithospheric mantle reconstructed using data from unique xenolith suite.
Fifteen North Cascade Arc basalts and andesites were analyzed for Mg isotopes to investigate the extent and manner of crustal contributions to this magmatic system. The δ26Mg of these samples vary ...from within the range of ocean island basalts (the lightest being -0.33 ± 0.07‰) to heavier compositions (as heavy as -0.15 ± 0.06‰). The observed range in chemical and isotopic composition is similar to that of other volcanic arcs that have been assessed to date in the circum-pacific subduction zones and in the Caribbean. The heavy Mg isotope compositions are best explained by assimilation and fractional crystallization within the deep continental crust with a possible minor contribution from the addition of subducting slab-derived fluids to the primitive magma. The bulk mixing of sediment into the primitive magma or mantle source and the partial melting of garnet-rich peridotite are unlikely to have produced the observed range of Mg isotope compositions. The results show that Mg isotopes may be a useful tracer of crustal input into a magma, supplementing traditional methods such as radiogenic isotopic and trace element data, particularly in cases in which a high fraction of crustal material has been added.
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