Antimicrobial polymer-based zeolite imidazolate framework composite membranes for uranium extraction from wastewater and seawater.

Extraction uranium (VI) (U(VI)) from wastewater and seawater is highly important for environmental protection and life safety, but it remains a great challenge. In this work, the growth of the zeolitic imidazolate framework-8 (ZIF-8) nanoparticles on the tannic acid (TA)-3-aminopropyltriethoxysilane (APTES) modified PVDF (TAP) membrane was designed to obtain an excellent U(VI) adsorbent. The zeolite imidazolate framework composite membrane (TAPP-ZIF-60) was prepared through polyethyleneimine (PEI) bridging strategy and temperature regulation strategy in solvothermal method. The coordination bond between PEI and ZIF-8 and the covalent bond between PEI and TAP are essential in forming stable composite membrane. TAPP-ZIF with different properties was synthesized through a temperature regulation process and the TAPP-ZIF prepared at 60 °C has the uniform morphology and good performance. The adsorption capacity of TAPP-ZIF-60 is 153.68 mg/g (C0 = 95.01 mg/L and pH = 8.0) and water permeability is 5459 L m-2 h-1 bar-1. After ten adsorption-desorption cycles, it is proved that TAPP-ZIF-60 has good repeatability and stability. In addition, the TAPP-ZIF-60 composites membrane has a good inhibitory effect on Staphylococcus aureus and Escherichia coli. X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) analysis reveal that the coordination between TAPP-ZIF-60 and uranyl ions is the primary factor contributing to the high adsorption capacity.

Ti3C2Tx/Cd0.8Zn0.2S composites constructed of Schottky heterojunction for efficient photocatalytic reduction of U(VI).

Photocatalysis has emerged as a extremely promising green technology for the treatment of uranium-containing wastewater. This study focuses on the fabrication of Ti3C2Tx/Cd0.8Zn0.2S composites with Schottky junctions through the in-situ growth of Cd0.8Zn0.2S on Ti3C2Tx nanosheets, enabling efficient photoreduction of U(VI) without the requirement of sacrificial agents. The results demonstrate that the Ti3C2Tx/Cd0.8Zn0.2S composites achieve remarkable 99.48 % U(VI) reduction efficiency within 60 min in a 100 ppm uranium solution. Furthermore, the removal rate remains above 90 % after five cycles. The formation of Schottky heterojunctions by Ti3C2Tx and Cd0.8Zn0.2S leads to the generation of an internal electric field that significantly promotes the rapid separation and transfer of photogenerated carriers, thereby enhancing the photocatalytic reduction efficiency of Ti3C2Tx/Cd0.8Zn0.2S-3:100 (TC/CZS-3:100). A considerable amount of electrons accumulate on Ti3C2Tx via the Schottky barrier, effectively facilitating the reduction of U(VI) to U(IV). As a co-catalyst, Ti3C2Tx enhances the photocatalytic performance and stability of Cd0.8Zn0.2S. Moreover, the practical application in the waste liquid of rare earth tailings reveals that the removal rate can be as high as 91.24 %. This research is of significant value in the development of effective photocatalysts for the elimination of uranium from wastewater.

The Electron-Density Distribution of UCl4 and Its Topology from X-ray Diffraction.

The chemistry of $5f$ electrons in actinide complexes and materials is still poorly understood and represents a serious challenge and opportunity for experiment and theory. The study of the electron density distribution of the ground state of such systems through X-ray diffraction represents a unique opportunity to quantitatively investigate different chemical bonding interactions at once, but was considered ``almost impossible'' on heavy-atom systems, until very recently. Here, we present a combined experimental and theoretical investigation of the electron density distribution in UCl$_4$ crystals and comparison with the previously reported spin density distribution from polarized neutron diffraction. All approaches provide a consistent picture in terms of electron and spin density distribution, and chemical bond characterization. More importantly, the synergy between experiments and quantum-mechanical calculations allows to highlight the remarkable sensitivity of X-ray diffraction to $5f$ electrons in materials.

Radiological risk and impact on soil microbial diversity of radionuclides in agricultural topsoils downstream of a decommissioned hydrometallurgical uranium plant.

Containing only low levels of U-bearing minerals, U ores often have to undergo hydrometallurgical processing for the separation of other minerals. Hydrometallurgical operations, even after being shut down, could pose radiological risk to the ecosystem and human health due to the radionuclide contamination of surrounding environmental media. This study investigated the contamination of radionuclides in the agricultural topsoils downstream of a decommissioned hydrometallurgical U plant in southern China, and assessed the corresponding radiological risk and evaluated its impact on soil microbial communities. The values of geoaccumulation index and potential ecological risk index indicate that all soil samples were significantly contaminated with U and 226Ra, with their concentrations being 4.4-28.7 times and 4.4-114.8 times higher than the corresponding regional background values, respectively. The mean outdoor annual effective dose (OAED) in the sampling plot next to the drainage ditch downstream of the decommissioned plant was up to 3.9 and 8.2 times higher than the Chinese annual effective dose limit and global average, respectively, which is indicative of unacceptable radiological risk for the local farm workers. Soil microbial composition was obviously impacted by the soil physicochemical properties and radionuclides. Specifically, Cladophialophora, which belongs to the fungal genus, exhibited significantly positive correlations with the contents of total Cd, total U, organic U, residual U, and total K, while Methanosarcina, which belongs to the archaeal genus, exhibited significantly positive correlations with the contents of 226Ra and residual U. Soil pH and total N content were significantly correlated with the abundance of several bacterial genera and the dominant archaeal genus (i.e., Candidatus Nitrocosmicus). These findings demonstrate the existence of potentially significant radiological risk associated with the radionuclides released from historical hydrometallurgical processing of U ores to the surrounding environment, and the need for proper site management and remediation.

Constructing Ce-OH groups on CeO2 for enhancing removal and recovery of uranium from wastewater and seawater.

Efficient recovery of uranium from wastewater and seawater provides an important guarantee for the sustainable growth of nuclear energy. Herein, we skillfully use the alkali etching method to construct CeO2 hollow spheres rich in Ce-OH groups for the removal and recovery of uranium from water matrixes. It is found that the CeO2 exhibits fast adsorption kinetics (equilibrium time within 10 min) and moderate adsorption capacity (143.1 mg/g), and the removal efficiency of low concentration uranium (0.1 g/L and 1 g/L) reaches 100% within 1 min of adsorption. Moreover, the adsorption of uranium by CeO2 is almost unaffected by common anions and cations in the environment, even if the concentration of anions is 1000 times that of uranium. More importantly, the CeO2 can enrich uranium concentration in seawater by 167.9 times and the recovery rate reaches 83.9%. Mechanistic studies reveal that the adsorption of uranium by CeO2 is mainly attributed to the rich Ce-OH groups on the surface of CeO2, resulting in the rapid adsorption of U(VI) and mainly forms a single-bridge model. The findings of this study provide a green and efficient path for the removal and recovery of uranium from wastewater and seawater.

New insights into uranium biomineralization mediated by Pseudomonas sp. WG2-6 in the presence of organic phosphorus: Promoting effect of extracellular polymeric substance and formation of U-P nanominerals.

Microbial biomineralization significantly affects the uranium (U) behavior in the environment. However, the mechanism of microbial biomineralization of U is still not fully understood. In this study, a dominant bacterium (Pseudomonas sp. WG2-6) was isolated from U tail mining area. Abiotic precipitation tests demonstrated that U biomineralization was entirely attributed to the mediation of Pseudomonas sp. WG2-6 when the concentration ratio of exogenous ß-glycerophosphate (SGP) to U was 10:1. Pseudomonas sp. WG2-6 exhibited strong immobilization ability towards U (97.59 %) according to batch experiments, and acylamide, carbonyls, and phosphate groups were the main functional groups that interacted with U. Besides, U mainly existed in the form of amorphous U-P complexes after biomineralization by Pseudomonas WG2-6, which could be converted into crystalline nano-minerals H2(UO2)2(PO4)2·8H2O in the presence of SGP. In particular, the formation and structural composition changes of extracellular polymeric substance (EPS) as well as the decrease in U4f binding energy were observed during the U biomineralization process of Pseudomonas sp. WG2-6 in the presence of SGP, indicating that EPS provided the nucleation site for the formation of stable biomineralized products. This work provides new insight into the mechanism of U microbial biomineralization and a theoretical basis for the remediation of U contaminated environments through microbial biomineralization.

Uranium Repartitioning during Microbial Driven Reductive Transformation of U(VI)-Sorbed Schwertmannite and Jarosite.

This study exposes U(VI)-sorbed schwertmannite and jarosite to biotic reductive incubations under field-relevant conditions and examines the changes in aqueous and solid-phase speciation of U, Fe, and S as well as associated microbial communities over 180 days. The chemical, X-ray absorption spectroscopy, X-ray diffraction, and microscopic data demonstrated that the U(VI)-sorbed schwertmannite underwent a rapid reductive dissolution and solid-phase transformation to goethite, during which the surface-sorbed U(VI) was partly reduced and mostly repartitioned to monomeric U(VI)/U(IV) complexes by carboxyl and phosphoryl ligands on biomass or organic substances. Furthermore, the microbial data suggest that these processes were likely driven by the consecutive developments of fermentative and sulfate- and iron- reducing microbial communities. In contrast, the U(VI)-sorbed jarosite only stimulated the growth of some fermentative communities and underwent very limited reductive dissolution and thus, remaining in its initial state with no detectable mineralogical transformation and solid-phase U reduction/repartitioning. Accordingly, these two biotic incubations did not induce increased risk of U reliberation to the aqueous phase. These findings have important implications for understanding the interactions of schwertmannite/jarosite with microbial communities and colinked behavior and fate of U following the establishment of reducing conditions in various acidic and U-rich settings.

Microbial production of methyl-uranium via the Wood-Ljungdahl pathway.

The misuse of uranium is a major threat to human health and the environment. In microbial ecosystems, microbes deploy various strategies to cope with uranium-induced stress. However, the exact ecological strategies and mechanisms underlying uranium tolerance in microbes remain unclear. Therefore, this study aimed to investigate the survival strategies and tolerance mechanisms of microbial communities in uranium-contaminated soil and groundwater. Microbial co-occurrence networks and molecular biology techniques were used to analyze the properties of microbes in groundwater and soil samples from various depths of uranium-contaminated areas in Northwest China. Uranium pollution altered microbial ecological strategies. Uranium stress facilitated the formation of microbial community structures, leading to symbiosis. Furthermore, microbes primarily resisted uranium hazards by producing polysaccharides and phosphate groups that chelate uranium, releasing phosphate substances that precipitate uranium, and reducing U(VI) through sulfate- and iron-reducing processes. The relative abundance of metal-methylation genes in soil microorganisms positively correlated with uranium concentration, indicating that soil microorganisms can produce methyl uranium via the Wood-Ljungdahl pathway. Furthermore, soil and groundwater microorganisms demonstrated different responses to uranium stress. This study provides new insights into microbial responses to uranium stress and novel approaches for the bioremediation of uranium-contaminated sites.

Precise Electrocatalysis on Fe-Porphyrin Conjugated Networks Achieves Energy-Efficient Extraction of Uranium.

Electrochemical extraction has the potential to enhance uranium (U) extraction capacity and rates, but thus far, high selectivity and energy efficiency have not been achieved through the design of electrode materials. Herein, a precise electrocatalysis strategy is developed using a Ferrum (Fe) porphyrin-phenanthroline conjugated network (Fe@PDACN) for energy-efficient uranium extraction. The phenanthroline provides specific binding sites for selective enrichment of U(VI) at active sites (Kd = 2.79 × 105 mL g-1 in multi-ion solution). The Fe(II) sites have strong trap-redox activity for U(VI) and act as dynamic electron donors to rapidly mediate electrocatalytic U(VI) extraction through the redox reaction of Fe(0/II)/Fe(III). Moreover, the Fe-porphyrin blocks support sustained electron donation for U(VI) electrocatalysis by pre-storing electrons. These features enable selective uranium capture and a high electroextraction capacity of 24 646.3 mg g-1 from simulated nuclear wastewater in 280 h at a low voltage of -1.5 V. An ultra-high Faraday efficiency of 90.1% is achieved, and the energy cost is 3.22 × 10-2 $ kg-1 U, significantly lower than the previously reported materials. This work provides a highly efficient strategy for uranium extraction from water.

Anti-Biofouling Polyzwitterion-Poly(amidoxime) Composite Hydrogel for Highly Enhanced Uranium Extraction from Seawater.

Amidoxime-functionalized hydrogels are one of most promising adsorbents for high-efficiency uranium (U) extraction from seawater, but bioadhesion on their surface seriously decreases their adsorption efficiency and largely shortens their service life. Herein, a semi-interpenetrating zwitterion-poly(amidoxime) (ZW-PAO) hydrogel was explored through introducing a PAO polymer into a poly [3-(dimethyl 4-vinylbenzyl amino) propyl sulfonate] (PDVBAP) polyzwitterionic (PZW) network via ultraviolet (UV) polymerization. Owing to the anti-polyelectrolyte effect of the PZW network, this ZW-PAO hydrogel can provide excellent super-hydrophilicity in seawater for high-efficiency U-adsorption from seawater. Furthermore, the ZW-PAO hydrogel had outstanding anti-biofouling performance for both highly enhanced U-adsorption and a relatively long working life in natural seawater. As a result, during only 25 days in seawater (without filtering bacteria), the U-uptake amount of this ZW-PAO hydrogel can reach 9.38 mg/g and its average rate can reach 0.375 mg/(g∙day), which is excellent among reported adsorbents. This work has explored a promising hydrogel for high-efficiency U-recovery from natural seawater and will inspire new strategy for U-adsorbing materials.

Identification and Quantification of Multiphase U(VI) Speciation on Gibbsite with pH Using TRLFS and PARAFAC of Excitation Emission Matrices.

The significant abundance of uranium in radioactive waste inventories worldwide necessitates a thorough understanding of its behavior. In this work, the speciation of uranyl(VI), (UO22+) in a gibbsite system under ambient conditions has been determined as a function of pH by deconvolution and analysis of luminescence spectroscopic data. Uniquely, a combined experimental and statistical approach utilizing time-resolved luminescence spectroscopy and parallel factor analysis (PARAFAC) of excitation emission matrices has been successfully utilized to identify four separate luminescent U(VI) species in the uranyl-gibbsite system for the first time. The speciation of all luminescent U(VI) species in an environmentally relevant system over a pH range of 6-11 is discerned through the analysis of emission fingerprints at low temperature (20 K). Comparison of the deconvoluted luminescence spectra with mineral standards and geochemical models of the system allows the assignment of the luminescent chemical species as metaschoepite, Na-compreignacite, surface adsorbed ≡AlO2-UO2(OH) and ≡AlO2-UO2(CO3)24- complexes, with assignments supported by fitting of extended X-ray absorption fine structure data. The combined spectroscopic techniques in this study show that assignment and quantification of uranyl(VI) species in a sorption system over a large pH range can be accurately achieved using PARAFAC to deconvolute a three way emission spectroscopic data set.

Removal of metals and assimilable organic carbon by activated carbon and reverse osmosis point-of-use water filtration systems.

Activated carbon (AC) systems and reverse osmosis (RO) systems are commonly used point-of-use (POU) water filtration systems for removing trace-level contaminants in tap water to protect human health. However, limited research has been done to evaluate their effectiveness in removing heavy metals like manganese (Mn) and uranium (U), or to assess the potential for undesired microbial growth within POU systems, which can reduce their treatment efficiency. This study aimed to systematically evaluate the removal of metals and assimilable organic carbon (AOC) in POU systems. AC systems were operated to 200% of their designed treatment capacities and RO systems were run for three weeks. The results showed that AC systems were generally ineffective at removing metals from drinking water, while RO systems effectively removed them. Both Mn and U were poorly removed by AC systems. Calcium (Ca) and magnesium (Mg) were poorly removed by AC systems, with efficiencies of less than 1%. Iron (Fe) removal by AC systems varied between 61% and 84%. Copper (Fe), likely due to its low influent concentration (<30 µg L-1), was effectively removed by AC systems with efficiencies over 95%. In contrast, RO systems consistently removed all metals effectively. Mn and U removal in RO systems exceeded 95%, while Ca, Mn, Fe, and Cu were all removed with efficiencies greater than 98%. AOC was effectively removed from all AC and RO systems, but with high variability in removal efficiency, which is likely attributed to the heterogeneity of biofilm and microbial growth within the POU systems. The new knowledge generated from this study can improve our understanding of chemical contaminant removal in POU systems and inform the development of better strategies for designing and operating POU systems to remove chemical contaminants in drinking water and mitigate their associated health risks.

A novel hydrogel composite of chitosan-phytic acid complex with PAAm: Characterization and adsorptive properties for UO22+and methylene blue.

The composite of a polyelectrolyte combination of chitosan and phytic acid (CsPa) and its entrapped form in polyacrylamide (PAAmCsPa) were synthesized. The composites were characterized by a number of methods including ATR-FTIR, SEM-EDX, XRD and XPS. The adsorptive properties of CsPa and PAAmCsPa were analyzed and modelled for UO22+ and methylene blue (MB+). The results showed that the composites exhibited physico-chemical properties that were both inherited from the components as well as unique to them. The isotherms of UO22+ and MB+ were L-type Giles isotherms. The adsorption kinetics followed the pseudo-second-order model, in contrast to the Langmuir model, which predicts first-order kinetics for both species. According to the Weber-Morris model, the nature of the adsorption process was ion exchange and/or complex formation for both composites and ions. The thermodynamics showed that the adsorption process was endothermic (ΔH > 0), with increasing entropy (ΔS > 0) and spontaneous (ΔG < 0). The reusability tests of the composites for UO22+ adsorption showed that the composites were substantially reusable for 6 cycles. The composites were selective for UO22+ over MB+ ions, and UO22+ adsorption increased significantly when MB+ adsorbed composites were used. Reproducible measurements demonstrating the storability of the composites were obtained over a period of approximately one year.

Urinary Metal Levels and Coronary Artery Calcification: Longitudinal Evidence in the Multi-Ethnic Study of Atherosclerosis.

BACKGROUND: Exposure to metals, a newly recognized risk factor for cardiovascular disease (CVD), could be related to atherosclerosis progression. OBJECTIVES: The authors hypothesized that higher urinary levels of nonessential (cadmium, tungsten, uranium) and essential (cobalt, copper, zinc) metals previously associated with CVD would be associated with baseline and rate of change of coronary artery calcium (CAC) progression, a subclinical marker of CVD in MESA (Multi-Ethnic Study of Atherosclerosis). METHODS: We analyzed data from 6,418 MESA participants with spot urinary metal levels at baseline (2000-2002) and 1 to 4 repeated, continuous measures of CAC over a 10-year period. We used linear mixed-effect models to assess the association of baseline urinary metal levels with baseline CAC and cumulative change in CAC over a 10-year period. Urinary metals (µg/g creatinine) and CAC were log transformed. Models were adjusted for baseline sociodemographic factors, estimated glomerular filtration rate, lifestyle factors, and clinical factors. RESULTS: At baseline, the median CAC was 6.3 (Q1-Q3: 0.7-58.2). Comparing the highest to lowest quartile of urinary cadmium, CAC levels were 51% (95% CI: 32%, 74%) higher at baseline and 75% (95% CI: 47%, 107%) higher over the 10-year period. For urinary tungsten, uranium, and cobalt, the corresponding CAC levels over the 10-year period were 45% (95% CI: 23%, 71%), 39% (95% CI: 17%, 64%), and 47% (95% CI: 25%, 74%) higher, respectively, with no difference for models with and without adjustment for clinical factors. For copper and zinc, the corresponding estimates dropped from 55% to 33% and from 85% to 57%, respectively, after adjustment for clinical factors. The associations of metals with CAC were comparable in magnitude to those for classical CVD risk factors. CONCLUSIONS: Exposure to metals was generally associated with extent of coronary calcification at baseline and follow-up. These findings support that metals are associated with the progression of atherosclerosis, potentially providing a novel strategy for the prevention and treatment of atherosclerosis progression.

Ultratrace Uranium Removal by Covalent Organic Frameworks on an In-Situ-Decorated Sponge as Integral Materials.

Herein, a sulfonated covalent organic framework (COF-SO3H) is prepared in situ on melamine sponge (MS) to produce MS@COF-SO3H as integral materials by a one-pot synthesis in water at room temperature, for facile deep removal of trace uranium-containing wastewater. The -SO3H on the COFs is able to form complexation with UO22+ through strong coordination interactions, and MS@COF-SO3H is therefore highly selective for UO22+ (Kd = 52603 mL g-1). The adsorption efficiency of MS@COF-SO3H-3 can reach 97.9% and 87.5% when the initial UO22+ concentration is 100 and 5 µg L-1, respectively, and the minimum residual UO22+ concentration is as low as 0.478 µg L-1, far lower than that in previous reports. In addition, MS@COF-SO3H exhibits excellent durability as an adsorbent, and its adsorption efficiency for UO22+ is still as high as 92.4% even after 5 cycles of recycling. The mild preparation conditions and excellent performance of MS@COF-SO3H make it quite promising as a highly efficient adsorbent for uranium removal. This work provides an important clue to prepare adsorbents facilely for nuclear wastewater deep treatment.

In-situ assembly of polyoxometalate-based metal-organic framework for high-efficiency recovery of uranium.

Extracting uranium from water is crucial for environmental protection and the sustainable nuclear power industry. However, high-efficiency extraction and mild desorption condition still poses significant challenges. Herein, a polyoxometalate-based metal-organic framework (POMOF) for high-performance uranium extraction is prepared by in situ confined encapsulating H3[PW12O40] (PW12) into MIL-101(Cr). The highly dispersed PW12 enables adsorption sites to be sufficiently exposed, supports the pore structure of MIL-101(Cr), while being protected by spatial confinement. Furthermore, its abundant oxygen groups form high-affinity coordination with uranium and provide the pH-dependent conformation switch to achieve selective adsorption and instantaneous structural transformation. The assembly of structure and function makes POMOF exhibit substantial synergistic stability and adsorption capacity. Consequently, the constructed MIL-101(Cr)@PW12 exhibits excellent uranium adsorption ability of 461.88 mg/g, as well as superior selectivity towards a wide variety of metal ions. Remarkably, instantaneous desorption can be achieved in 2 s under mild desorption conditions of 0.005 mol/L HCl, and the adsorption capacity remained at 94.30 % after 8 adsorption cycles. POMOF demonstrates the vast potential for uranium capture from water and offers new insight into designing structure and functional synergistic materials for the selective adsorption and instantaneous desorption of uranium.

Effects of Detoxifying Substances on Uranium Removal by Bacteria Isolated from Mine Soils: Performance, Mechanisms, and Bacterial Communities.

In this study, we investigated the effect of detoxifying substances on U(VI) removal by bacteria isolated from mine soil. The results demonstrated that the highest U(VI) removal efficiency (85.6%) was achieved at pH 6.0 and a temperature of 35 °C, with an initial U(VI) concentration of 10 mg/L. For detoxifying substances, signaling molecules acyl homoserine lactone (AHLs, 0.1 µmol/L), anthraquinone-2, 6-disulfonic acid (AQDS, 1 mmol/L), reduced glutathione (GSH, 0.1 mmol/L), selenium (Se, 1 mg/L), montmorillonite (MT, 1 g/L), and ethylenediaminetetraacetic acid (EDTA, 0.1 mmol/L) substantially enhanced the bacterial U(VI) removal by 34.9%, 37.4%, 54.5%, 35.1%, 32.8%, and 47.8% after 12 h, respectively. This was due to the alleviation of U(VI) toxicity in bacteria through detoxifying substances, as evidenced by lower malondialdehyde (MDA) content and higher superoxide dismutase (SOD) and catalase (CAT) activities for bacteria exposed to U(VI) and detoxifying substances, compared to those exposed to U(VI) alone. FTIR results showed that hydroxyl, carboxyl, phosphorus, and amide groups participated in the U(VI) removal. After exposure to U(VI), the relative abundances of Chryseobacterium and Stenotrophomonas increased by 48.5% and 12.5%, respectively, suggesting their tolerance ability to U(VI). Gene function prediction further demonstrated that the detoxifying substances AHLs alleviate U(VI) toxicity by influencing bacterial metabolism. This study suggests the potential application of detoxifying substances in the U(VI)-containing wastewater treatment through bioremediation.

Multi-method dating reveals 200 ka of Middle Palaeolithic occupation at Maras rock shelter, Rhône Valley, France.

The emergence of the Middle Palaeolithic, and its variability over time and space are key questions in the field of prehistoric archaeology. Many sites have been documented in the south-eastern margins of the Massif central and the middle Rhône valley, a migration path that connects Northern Europe with the Mediterranean. Well-dated, long stratigraphic sequences are essential to understand Neanderthals dynamics and demise, and potential interactions with Homo sapiens in the area, such as the one displayed at the Maras rock shelter ("Abri du Maras"). The site is characterised by exceptional preservation of archaeological remains, including bones dated using radiocarbon (14C) and teeth using electron spin resonance combined with uranium series (ESR/U-series). Optically stimulated luminescence was used to date the sedimentary deposits. By combining the new ages with previous ones using Bayesian modelling, we are able to clarify the occupation time over a period spanning 200,000 years. Between ca. 250 and 40 ka, the site has been used as a long-term residence by Neanderthals, specifically during three interglacial periods: first during marine isotopic stage (MIS) 7, between 247 ± 34 and 223 ± 33 ka, and then recurrently during MIS 5 (between 127 ± 17 and 90 ± 9 ka) and MIS 3 (up to 39,280 cal BP).

High-Performance Polyamidoxime Porous Membrane Prepared by the In Situ Modification/Nonsolvent-Induced Phase Separation Strategy for Uranium Extraction from Seawater.

The abundance of uranium (U(VI)) reserves in seawater makes it crucial to develop economically efficient methods for uranium extraction from seawater. In this work, an enhanced polyamidoxime porous membrane (PAOM) was fabricated by pre-in situ amidoxime modification combined with nonsolvent-induced phase separation (NIPS). The strategy of in situ modification of the polyacrylonitrile (PAN) solution served to enhance the homogeneity of the reaction and avoid the destruction of the membrane matrix and pore structure. Compared with the control sample (AOPM), PAOM possessed better mechanical strength and hydrophilicity. The introduction of polyvinylpyrrolidone (PVP) formed a porous structure in PAOM, improving spatial accessibility and facilitating the diffusion transport and capture of UO22+ inside the membrane. The more uniform and abundant distribution of amidoxime groups in PAOM gave it ultrahigh adsorption capacity and selectivity. The equilibrium adsorption capacity and Kd value of PAOM were 1.72 and 5.51 times higher than those of AOPM. Meanwhile, PAOM also demonstrated good recyclability, with only a 6.15% decrease in adsorption capacity after seven cycles. Additionally, PAOM exhibited excellent dynamic adsorption performance, and after 14 days of continuous filtration and adsorption, PAOM could extract 2.03 mg·g-1 U(VI) from natural seawater.