Using mobility data in the design of optimal lockdown strategies for the COVID-19 pandemic.

A mathematical model for the COVID-19 pandemic spread, which integrates age-structured Susceptible-Exposed-Infected-Recovered-Deceased dynamics with real mobile phone data accounting for the population mobility, is presented. The dynamical model adjustment is performed via Approximate Bayesian Computation. Optimal lockdown and exit strategies are determined based on nonlinear model predictive control, constrained to public-health and socio-economic factors. Through an extensive computational validation of the methodology, it is shown that it is possible to compute robust exit strategies with realistic reduced mobility values to inform public policy making, and we exemplify the applicability of the methodology using datasets from England and France.

Nanopharmaceuticals (Au-NPs) after use: Experiences with a complex higher tier test design simulating environmental fate and effect.

The current environmental hazard assessment is based on the testing of the pristine substance. However, it cannot be excluded that (nano)pharmaceuticals are excreted into sewage during the use phase followed by entry into wastewater treatment plants (WWTPs). Sorption to sewage sludge or release via effluent can result in modified ecotoxicological effects which possibly can only be detected with a modified test approach. The objective of our study was to investigate a realistic exposure scenario for metallic nanoparticles (NPs) in pharmaceutical products, excreted into effluent, and released into the environment after treatment in WWTPs. The test approach was illustrated by using gold (Au) NPs. Effluent from model WWTPs were investigated in aquatic tests (Daphnia magna, fish cell lines). Sewage sludge was used as a sole food source (Eisenia fetida) or mixed with soil and used as test medium (soil microorganisms, Folsomia candida, Enchytraeus crypticus). To cover the aspect of regulation, the test systems described in OECD-test guidelines (OECD TG 201, 211, 220, 232, 249, 317) were applied. Modifications and additional test approaches were included to meet the needs arising out of the testing of nanomaterials and of the exposure scenarios. The results were assessed regarding the suitability of the test design and the toxicity of Au-NPs. Except for activated sludge as a sole food source for E.fetida, the selected test approach is suitable for the testing of nanomaterials. Additional information can be gained when compared to the common testing of the pristine nanomaterials in the standardized test systems. Effects of Au-NPs were observed in concentrations exceeding the modeled environmental.

Unravelling the antitumoral potential of novel bis(thiosemicarbazonato) Zn(II) complexes: structural and cellular studies.

The development of pharmacologically active compounds based on bis(thiosemicarbazones) (BTSC) and on their coordination to metal centers constitutes a promising field of research. We have recently explored this class of ligands and their Cu(II) complexes for the design of cancer theranostics agents with enhanced uptake by tumoral cells. In the present work, we expand our focus to aliphatic and aromatic BTSC Zn(II) complexes bearing piperidine/morpholine pendant arms. The new complexes ZnL1-ZnL4 were characterized by a variety of analytical techniques, which included single-crystal X-ray crystallography for ZnL2 and ZnL3. Taking advantage of the fluorescent properties of the aromatic complexes, we investigated their cellular uptake kinetics and subcellular localization. Furthermore, we tried to elucidate the mechanism of action of the cytotoxic effect observed in human cancer cell line models. The results show that the aliphatic complexes (ZnL1 and ZnL2) have a symmetrical structure, while the aromatic counterparts (ZnL3 and ZnL4) have an asymmetrical nature. The cytotoxic activity was higher for the aromatic BTSC complexes, as well as the cellular uptake, evaluated by measurement of intracellular Zn accumulation. Among the most active complexes, ZnL3 presented the fastest uptake kinetics and lysosomal localization assessed by live-cell microscopy. Detailed studies of its impact on cellular production of reactive oxygen species and impairment of lysosomal membrane integrity reinforced the influence of the pendant piperidine in the biological performance of aromatic BTSC Zn(II) complexes.

Widening the spectrum of deletions and molecular mechanisms underlying alpha-thalassemia.

Inherited deletions of α-globin genes and/or their upstream regulatory elements (MCSs) give rise to α-thalassemia, an autosomal recessive microcytic hypochromic anemia. In this study, multiplex ligation-dependent probe amplification performed with commercial and synthetic engineered probes, Gap-PCR, and DNA sequencing were used to characterize lesions in the sub-telomeric region of the short arm of chromosome 16, possibly explaining the α-thalassemia/HbH disease phenotype in ten patients. We have found six different deletions, in heterozygosity, ranging from approximately 3.3 to 323 kb, two of them not previously described. The deletions fall into two categories: one includes deletions which totally remove the α-globin gene cluster, whereas the other includes deletions removing only the distal regulatory elements and keeping the α-globin genes structurally intact. An indel was observed in one patient involving the loss of the MCS-R2 and the insertion of 39 bp originated from a complex rearrangement spanning the deletion breakpoints. Finally, in another case, no α-globin gene cluster deletion was found and the patient revealed to be a very unusual case of acquired α-thalassemia-myelodysplastic syndrome. This study further illustrates the diversity of genomic lesions and underlying molecular mechanisms leading to α-thalassemia.

Enchytraeus crypticus fitness: effect of density on a two-generation study.

Organisms' density can influence physiological processes related with fitness. In the present study we assessed the influence of organisms' density on the life-history parameters in two consecutive generations in Enchytraeus crypticus (Oligochaeta), a standard model in soil ecotoxicology. The densities tested were 1 (N1) and 20 (N20) organisms per replicate and 10 vs. 20 g of soil (for the 2nd generation test only). Results showed that reproductive output was affected by density, with organisms in N1 producing three times more juveniles per adult than when at N20. Organisms' length was affected by both density and space, i.e., organisms were smaller when less space available. Further, the density of parental generation (F0) had no influence on the endpoints reproduction and length assessed in F1, hence there was no transference of effects. These findings have potential implications in the standard Enchytraeid Reproduction Test, i.e. early mortality of the adults during toxicant exposure can affect the number and size of the offspring and the final results will also reflect the density related changes in reproduction.

Effect of Cu and Ni on cellular energy allocation in Enchytraeus albidus.

Effects of nickel and copper on Enchytraeus albidus (Oligochaeta) were investigated using the cellular energy allocation approach. This methodology is used to evaluate the energetic status of an organism and is indicative of its overall condition. Enchytraeids were exposed to the reproduction Effect Concentrations (EC50 and EC90), and the parameters measured were the total energy reserves available (protein, carbohydrate and lipid budgets) and the energy consumption [based on electron transport system activity] which were further integrated to obtain the cellular energy allocation over different periods of exposure (0-2, 2-4 and 4-8 days). Carbohydrates (in comparison to lipids and proteins) were the only energy source mobilized in the case of nickel within 8 days of exposure. For copper exposure, protein budgets were also strongly reduced. Energy consumption increased in a time and dose-dependent way for copper and in the longer exposure period (4-8 days) at the EC90 for Ni exposure, indicating that this is a good biomarker for effects of short-time metal exposure, while cellular energy allocation was only significantly reduced for the EC90 of copper (4-8 days) and EC50 of nickel (2-4 days). The effects of nickel at concentrations causing 50 and 90 % decrease in reproduction were likely not due to the changes in cellular energy allocation within 8 days of exposure.

The hepcidin gene promoter nc.-1010C > T; -582A > G haplotype modulates serum ferritin in individuals carrying the common H63D mutation in HFE gene.

Hereditary hemochromatosis is an autosomal recessive disorder characterized by severe iron overload. It is usually associated with homozygosity for the HFE gene mutation c.845G > A; p.C282Y. However, in some cases, another HFE mutation (c.187C > G; p.H63D) seems to be associated with the disease. Its penetrance is very low, suggesting the possibility of other iron genetic modulators being involved. In this work, we have screened for HAMP promoter polymorphisms in 409 individuals presenting normal or increased serum ferritin levels together with normal or H63D-mutated HFE genotypes. Our results show that the hepcidin gene promoter TG haplotype, originated by linkage of the nc.-1010C > T and nc.-582A > G polymorphisms, is more frequent in the HFE_H63D individuals presenting serum ferritin levels higher than 300 µg/L than in those presenting the HFE_H63D mutation but with normal serum ferritin levels or in the normal control group.Moreover, it was observed that the TG haplotype was associated to increased serum ferritin levels in the overall pool of HFE_H63D individuals. Thus, our data suggest that screening for these polymorphisms could be of interest in order to explain the phenotype. However, this genetic condition seems to have no clinical significance.

Pseudo-Bartter syndrome as the initial presentation of cystic fibrosis in children: an important diagnosis not to be missed.

Pseudo-Bartter syndrome (PBS) is characterised by hyponatraemic, hypochloraemic metabolic alkalosis that mimics Bartter syndrome, without renal tubular disease. We present a case of an infant with a positive cystic fibrosis (CF) newborn screening, hospitalised during the summer with dehydration, oliguria and apathy. Blood analysis revealed hypochloraemic metabolic alkalosis, hypokalaemia and hyponatraemia. Urine analysis showed leucocyturia with reduced sodium and chloride excretion fraction, and urinary culture was positive for Citrobacter koseri After antibiotherapy and intravenous rehydration with additional supplementation of sodium and chloride, the patient recovered completely. PBS is one of CF complications that is especially prevalent in infants and young children with increased sweating and/or other causes of additional loss of sodium and chloride. Clinical awareness of this syndrome and its strong clinical suspicion are extremely important for an early diagnosis and treatment of CF, particularly in countries where the universal screening of CF is not routinely performed.

Iron Oxide (Magnetite)-Based Nanobiomaterial with Medical Applications-Environmental Hazard Assessment Using Terrestrial Model Species.

Nanobiomaterials (NBMs) have tremendous potential applications including in cancer diagnosis and treatment. However, the health and environmental effects of NBMs must be thoroughly assessed to ensure safety. Fe3O4 (magnetite) nanoparticles coated with polyethylene glycol (PEG) and poly (lactic-co-glycolic acid) (PLGA) were one of the focus NBMs within the EU project BIORIMA. Fe3O4 PEG-PLGA has been proposed to be used as a contrast agent in magnetic resonance imaging for the identification of solid tumors and has revealed low cytotoxicity in several cell lines. However, the effects of Fe3O4 PEG-PLGA have not been assessed in terrestrial environments, the eventual final sink of most materials. In the present study, the effects of Fe3O4 PEG-PLGA and its precursor, (un-coated) Fe3O4 NMs, were assessed in soil model invertebrates Enchytraeus crypticus (Oligochaeta) and Folsomia candida (Collembola). The endpoints were survival, reproduction, and size, based on the standard OECD test (28 days) and its extension (56 days). The results showed no toxicity for any of the endpoints evaluated, indicating that the NBM Fe3O4 PEG-PLGA poses no unacceptable risk to the terrestrial environment.

Safe and sustainable by design Ag nanomaterials: A case study to evaluate the bio-reactivity in the environment using a soil model invertebrate.

Safe-and-sustainable-by-design (SSbD) nanomaterials (NMs) or NM-containing products are a priority. Silver (Ag) NMs have a vast array of applications, including biomedical and other products, even as nanopesticides. Thus, their release to the environment is expected to increase. The aim of the present study was to assess the ecotoxicity of the SSbD Ag NM to the soil model species Enchytraeus crypticus (Oligochaeta). The Ag NM tested consists in a SSbD Ag with biomedical applications, a hydroxyethyl cellulose (HEC) coated Ag NMs (AgHEC) and its toxicity was compared to the naked Ag NMs (Ag-Sigma), an Ag-based biomedical product (PLLA-Ag: Poly l-Lactide microfibers doped with Ag), and AgNO3. Effects were assessed both in soil and aqueous media, following the standard OECD guideline in soil (28 days) and the OECD extension (56 days), and short-term pulse (5 days) in aqueous media: reconstituted water (ISO water) and soil:water (S:W) extracts, followed by a 21-days recovery period in soil. Ag materials were thoroughly characterized as synthesized and during the test in media and animals. Results in S:W showed AgHEC was more toxic than Ag-Sigma (ca. 150 times) and PLLA-Ag (ca. 2.5 times), associated with a higher Ag uptake. Higher toxicity was related to a smaller hydrodynamic size and higher suspension stability, which in turn resulted in a higher bioavailability of Ag NMs and released ions, particularly in S:W. Toxicity was correlated with the main physicochemical features, providing useful prediction of AgNMs bioactivity. The ability to test E. crypticus in a range of media with different and/or increasing complexity (water, S:W extracts, soil) provided an excellent source to interpret results and is here recommended.

Machine Learning Allowed Interpreting Toxicity of a Fe-Doped CuO NM Library Large Data Set─An Environmental In Vivo Case Study.

The wide variation of nanomaterial (NM) characters (size, shape, and properties) and the related impacts on living organisms make it virtually impossible to assess their safety; the need for modeling has been urged for long. We here investigate the custom-designed 1-10% Fe-doped CuO NM library. Effects were assessed using the soil ecotoxicology model Enchytraeus crypticus (Oligochaeta) in the standard 21 days plus its extension (49 days). Results showed that 10%Fe-CuO was the most toxic (21 days reproduction EC50 = 650 mg NM/kg soil) and Fe3O4 NM was the least toxic (no effects up to 3200 mg NM/kg soil). All other NMs caused similar effects to E. crypticus (21 days reproduction EC50 ranging from 875 to 1923 mg NM/kg soil, with overlapping confidence intervals). Aiming to identify the key NM characteristics responsible for the toxicity, machine learning (ML) modeling was used to analyze the large data set [9 NMs, 68 descriptors, 6 concentrations, 2 exposure times (21 and 49 days), 2 endpoints (survival and reproduction)]. ML allowed us to separate experimental related parameters (e.g., zeta potential) from particle-specific descriptors (e.g., force vectors) for the best identification of important descriptors. We observed that concentration-dependent descriptors (environmental parameters, e.g., zeta potential) were the most important under standard test duration (21 day) but not for longer exposure (closer representation of real-world conditions). In the longer exposure (49 days), the particle-specific descriptors were more important than the concentration-dependent parameters. The longer-term exposure showed that the steepness of the concentration-response decreased with an increased Fe content in the NMs. Longer-term exposure should be a requirement in the hazard assessment of NMs in addition to the standard in OECD guidelines for chemicals. The progress toward ML analysis is desirable given its need for such large data sets and significant power to link NM descriptors to effects in animals. This is beyond the current univariate and concentration-response modeling analysis.

Advanced materials - Food grade melatonin-loaded Lipid Surfactant Submicron Particles (LSSP)-environmental impacts.

Lipid-based nanoparticles (LNPs) are advanced materials (AdMa), particularly relevant for drug delivery of poorly water-soluble compounds, while also providing protection, stabilization, and controlled release of the drugs/active substances. The toxicological data available often focus on the specific applications of the LNPs-drug tested, with indication of low toxicity. However, the ecotoxicological effects of LNPs are currently unknown. In the present study, we investigated the ecotoxicity of a formulation of Lipid Surfactant Submicron Particles (LSSPs) loaded with melatonin at 1 mg/mL. The LSSPs formulation has been developed to be fully compliant with regulatory for its potential use in the market and all components are food additives. The same formulation without the thickening agent xanthan gum (stabilizer in water phase) designated as LSSP-xg, was also tested. Two soil model invertebrate species were tested in LUFA 2.2 soil: Enchytraeus crypticus (Oligochaeta) and Folsomia candida (Collembola). Effects were assessed based on the OECD standard guideline (28 days) and its extension, the longer-term exposure (56 days). Assessed endpoints were survival, reproduction, and size. LSSPs and LSSP-xg were toxic to E. crypticus and F. candida reducing their survival and reproduction in a dose-dependent way: e.g., 28-day exposure: E. crypticus: LC/EC50 = 30/15 mg LSSPs/kg soil and F. candida LC/EC50 = 55/44 mg LSSPs/kg soil, with similar values for LSSP-xg. Size was also reduced for F. candida but was the least sensitive endpoint. There were no indications that toxicity increased with longer term exposure. The results provide relevant information on ecotoxicity of a AdMa and highlights the need for awareness of the potential risks, even on products and additives usually used in food or cosmetic industry. Further information on single components and on their specific assembly is necessary for the interpretation of results, as it is not fully clear what causes the toxicity in this specific AdMa. This represents a typical challenge for AdMa hazard assessment scenario.

A 3D printed hydrogel to promote human keratinocytes' spheroid-based growth.

Tissue engineering uses cells and biomaterials to develop bioartificial tissue substitutes for different purposes. For example, although several skin models have been developed for pharmaceutical and cosmetic research and skin wound healing, there are few studies on 3D cultures of keratinocytes in 3D printed scaffolds. So, this work aimed to develop a 3D-printed hydrogel scaffold to promote human keratinocyte growth. Mesh 3D scaffolds were printed using an extrusion-based method with a 20% gelatin/5% alginate hydrogel, where HaCaT cells were cultured for 7 days. Scaffolds kept their structure for over 1 week, and their stiffness only decreased after 7 days, showing good mechanical and structural characteristics and biodegradability (27% weight lost). Viable keratinocytes (MTT assay) are aggregated into spheroids, a 3D model capable of mimicking in vivo cell properties and phenotypes. Spheroids were formed on 47% of scaffolds pores and grew over time, showing promising cell proliferation. F-actin staining showed cells' irregular and interconnected shapes and organization over time. This method offers an easy and inexpensive solution for keratinocyte spheroid formation, which may be helpful in tissue engineering as a cell delivery system, for pharmacological or basic research, or wound healing medical applications.

Congenital adrenal hyperplasia with a CYP21A2 deletion overlapping the tenascin-X gene: an atypical presentation.

OBJECTIVES: Congenital Adrenal Hyperplasia (CAH) is a group of genetic diseases characterized by impaired cortisol biosynthesis. 95% of CAH cases result from mutation in the CYP21A2 gene encoding 21-hydroxilase. TNX-B gene partially overlaps CYP21A2 and encodes a matrix protein called Tenascin-X (TNX). Complete tenascin deficiency causes Enlers-Danlos syndrome (EDS). A mono allelic variant called CAH-X CH-1 was recently described, resulting from a CYP21A2 complete deletion that extends into the TNXB. This haploinsufficiency of TNX may be associated with a mild hypermobility form of EDS, as well as other connective tissue comorbidities such as hernia, cardiac defects and chronic arthralgia. CASE PRESENTATION: We report four patients heterozygous for a CAH-X CH-1 allele that do not present clinical manifestations of the EDS. CONCLUSIONS: All CAH patients, carriers of these TNXA/TNXB chimeras, should be evaluated for clinical manifestations related to connective tissue hypermobility, cardiac abnormalities and other EDS features, allowing for better clinical surveillance management.

Environmental hazards of nanopesticides to non-target soil species - commercial nanoformulation versus its active substance (Karate Zeon® and lambda-cyhalothrin).

Nanopesticides (Npes) carry the potential of increased efficacy while reducing application rates, hence increasing agricultural productivity in a more sustainable way. However, given its novelty, the environmental risk assessment of these advanced materials is mostly absent. In the present study we investigated the ecotoxicity of a commercial insecticide, with reported nanofeatures, Karate Zeon®, and compared it to its active substance lambda-cyhalothrin. It is hypothesised that the use of the nanopesticide Karate Zeon® poses lower risk to enchytraeids than its active substance. The standard non-target soil invertebrate Enchytraeus crypticus was used, and exposure was done in LUFA 2.2 soil in 4 tests (endpoints: days): avoidance test [avoidance behaviour: 2 days], OECD standard reproduction test [survival, reproduction plus adults' size: 28 days] and its extension [total number organisms: 56 days], and Full Life Cycle (FLC) test [hatching and juveniles' size: 13 days; survival, reproduction and adults' size: 46 days]. Results showed that enchytraeids did not avoid Karate Zeon® nor its active substance lambda-cyhalothrin, which could be due to neurotoxicity. There was no indication of increased toxicity with prolonged exposure (46, 56d) compared to the standard (28d) for neither of the materials, being overall equally toxic in terms of hatching, survival, and reproduction. The FLCt results indicated that the juvenile stage was the most sensitive, resulting in higher toxicity for the adult animals when exposed from the cocoon stage. Although toxicity was similar between Karate Zeon and lambda-cyhalothrin, different patterns of uptake and elimination cannot be excluded. The benefits of using Karate Zeon will rely on reduced application rates.

Nanoemulsion carriers for drug delivery: Assessment of environmental hazards.

Nanoemulsions (NEs) have been extensively studied as carriers for drug delivery, since these provide a good alternative to the existing non-nano systems, while promoting their target delivery and controlled release. NEs are considered safe drug carriers from a pre-clinical perspective, but there is currently no information on their ecotoxicological effects. In the present study we investigated the toxicity of a NE material (lecithin, sunflower oil, borate buffer) designed to be used as a liposomal excipient for eye drops, further referred to as (Lipid Particle:LP) LP_Eye and its dispersant (borate buffer) (LP_Eye disp.). Effects were assessed using two model species in soil ecotoxicology in LUFA 2.2 soil: Enchytraeus crypticus (Oligochaeta) and Folsomia candida (Collembola), based on the OECD standard guideline (28 days) and its extension, a longer-term exposure (56 days). The endpoints evaluated included survival, reproduction, and size. LP_Eye and LP_Eye disp. were toxic to E. crypticus and F. candida, affecting all measured endpoints. The toxicity of LP_Eye in E. crypticus seemed to be induced by the dispersant, whereas for F. candida, more sensitive, this was less explanatory. There were no indications that toxicity increased with longer exposure. Current results provide ecotoxicological data for a group of NMs that was absent, revealing toxicity to relevant environmental species. Indications were that the dispersant contributed to most of the observed effects, thus there is room to improve the formulation and achieve lower environmental impact.

TiO2 nanoparticles' library toxicity (UV and non-UV exposure) - High-throughput in vivo transcriptomics reveals mechanisms.

The hazards of nanomaterials/nanoparticles (NMs/NPs) are mostly assessed using individual NMs, and a more systematic approach, using many NMs, is needed to evaluate its risks in the environment. Libraries of NMs, with a range of identified different but related characters/descriptors allow the comparison of effects across many NMs. The effects of a custom designed Fe-doped TiO2 NMs library containing 11 NMs was assessed on the soil model Enchytraeus crypticus (Oligochaeta), both with and without UV (standard fluorescent) radiation. Effects were analyzed at organism (phenotypic, survival and reproduction) and gene expression level (transcriptomics, high-throughput 4x44K microarray) to understand the underlying mechanisms. A total of 48 microarrays (20 test conditions) were done plus controls (UV and non-UV). Unique mechanisms induced by TiO2 NPs exposure included the impairment in RNA processing for TiO2_10nm, or deregulated apoptosis for 2%FeTiO2_10nm. Strikingly apparent was the size dependent effects such as induction of reproductive effects via smaller TiO2 NPs (≤12 nm) - embryo interaction, while larger particles (27 nm) caused reproductive effects through different mechanisms. Also, phagocytosis was affected by 12 and 27 nm NPs, but not by ≤11 nm. The organism level study shows the integrated response, i.e. the result after a cascade of events. While uni-cell models offer key mechanistic information, we here deliver a combined biological system level (phenotype and genotype), seldom available, especially for environmental models.

Environmental hazards of WELGRO® Cu+Zn: A nano-enabled fertilizer.

Nanoagrochemicals have the potential to revolutionize agriculture towards a precision farming system, able to reduce application rates and consequently their environmental footprint, while keeping efficacy. Several nanoagrochemicals (including nanopesticides (Npes) and nanofertilizers (Nfer)) are already commercialized but the environmental risk assessment of these advanced materials is often lacking. In the present study, we studied the commercial fertilizer WELGRO® Cu + Zn and assessed its ecotoxicity to the soil invertebrate species Enchytraeus crypticus (Oligochaeta), further comparing it to its individual active substances CuO and ZnO. To get a comprehensive picture of possible effects, we used four types of highly relevant tests in LUFA 2.2 soil: 1) avoidance behaviour (2 days), 2) reproduction (OECD standard, 28 d), 3) its extension (56 d), and 4) the full life cycle (FLC) (46 d) - this high level of hazard screening allows for increased interpretation. The results confirmed the nano-features of WELGRO® and a higher toxicity than the mixture of the individual components CuO + ZnO. E. crypticus avoided the soil spiked with WELGRO® and CuO + ZnO, this being the most sensitive endpoint - avoidance behaviour. Both WELGRO® and the active substances were little to non-toxic based on the OECD standard test. However, the toxicity dramatically increased in the tests focussing on longer-term sustainability measures, i.e., 56 days, ca. 170 for WELGRO®. This seems related to the nano-features of WELGRO®, e.g., slow release of ions from the nanoparticles throughout time. The FLCt results showed WELGRO® affected hatching and juveniles' survival, being these the most sensitive life stages. Hence, under actual real world field usage scenarios, i.e., based on the recommended application rates, nanoenabled WELGRO® can affect oligochaete populations like enchytraeids, both via the immediate avoidance behaviour and also via prolonged exposure periods.

Tentative Approaches for Extraction of Lanthanides from Wastewater with Low Metal Concentration.

Lanthanides are critical elements, and their recovery from wastewater increases the availability of these elements and reduces their impacts on the environment. In this study, tentative approaches to extract lanthanides from low-concentration aqueous solutions were investigated. PVDF membranes soaked with different active compounds or synthesized chitosan-based membranes containing these active compounds were used. The membranes were immersed in 10-4 M of aqueous solutions of selected lanthanides, and their extraction efficiency was assessed using ICP-MS. The PVDF membranes showed quite poor results, with only the membrane with oxamate ionic liquid giving some positive results (0.75 mg of Yb, 3 mg of lanthanides per gram of membrane). However, the chitosan-based membranes led to very interesting results, with the maximum concentration factor for the final solution relative to the initial solution being 13 times higher for Yb, which was obtained with the chitosan-sucrose-citric acid membrane. Several of the chitosan membranes, namely the one with 1-Butyl-3-methylimidazolium-di-(2-ethylhexyl)-oxamate, could extract around 10 mg of lanthanides per gram of membrane, with the better one being the membrane with sucrose/citric acid that achieved more than 18 mg/g of membrane. The use of chitosan for this purpose is a novelty. Since these membranes are easily prepared and have a very low cost, practical applications can be envisaged after further studies to better understand the underlying mechanism.