Salt Type Research Articles

Structure Prediction and Mechanical Properties of Tantalum Carbide (TaC) on ab initio Level

AbstractTantalum carbide (TaC) is an extremely hard, brittle, refractory ceramic material with excellent physical properties, which makes it a desirable material in e. g. aerospace industries. In order to explore the range of feasible modifications of TaC, we have executed a crystal structure prediction study of the TaC chemical system using a multi‐methodological approach, via enthalpy landscape explorations of pristine TaC at different pressures, supplemented by data mining searches in the ICSD database. Local structure relaxations have been accomplished by using Density Functional Theory (DFT). The global minimum is found to correspond to the equilibrium rock salt (NaCl) type modification. Additionally, eight new phases of tantalum carbide are predicted to be feasible: the WC‐type, the NiAs‐type, the 5‐5‐type, the ZnS‐type, the RingTaC‐type, the CsCl‐type, the OrthoTaC‐type, and the TetraTaC‐type. Furthermore, the elastic and mechanical properties of the predicted TaC modifications were explored on the DFT level of computation. The promising values of some of the mechanical properties of the proposed tantalum carbide modifications suggest that various scientific, industrial, and technological applications of TaC should be possible.

Influence of high-molecular-weight glutenin subunits and salt types on dough rheology and gluten aggregation: A combined experimental and computational approach

This study investigates the impact of various salts (NaCl, KCl, CaCl₂, MgCl₂) on gluten aggregation, with an emphasis on the role of high-molecular-weight glutenin subunits (HMW-GS) in modulating these impacts. The results demonstrated that NaCl significantly improved dough springiness and adhesiveness, while divalent salts like CaCl₂ and MgCl₂ had a greater effect on increasing dough hardness, with KCl showing the least impact among all salts. Differential responses were observed in HMW-GS deletion lines, where Bx7 was more responsive to NaCl and CaCl₂, whereas By8 showed stronger interactions with KCl and CaCl₂. The observed reductions in zeta potential and decrements in ionic bond content during salt-induced gluten aggregation supported the 'electrostatic shielding' mechanism, with hydrophobic interactions and hydrogen bonding emerging as key contributors to aggregate stability. Molecular dynamics simulations further corroborated these findings, revealing stronger Coulomb-SR interactions and enhanced binding affinities for divalent ions, in agreement with experimental data. These insights provide a theoretical foundation for optimizing low-sodium formulations in wheat-based products.

Development of a Negatively Charged Polyether Sulfone Membrane Enriched with MIL-101(Cr)-Modified Magnetic Activated Pyrolytic Coke for Enhanced Dye Removal, Permeability, and Antifouling Properties

Developing high-performance nanofiltration membranes for effectively treating wastewater contaminated with organic pollutants has become increasingly important. Given the hazardous nature of these contaminants, proper treatment of wastewater is crucial before it is released into natural water bodies. This study synthesized a novel composite membrane by incorporating Fe3O4@APC@MIL-101(Cr) nanocomposites into a polyether sulfone (PES) matrix using a phase inversion technique. The inclusion of 0.5wt.% Fe3O4@APC@MIL-101(Cr) significantly enhanced the membrane's hydrophilicity, porosity, and surface characteristics. The optimized membrane achieved an impressive pure water flux (PWF) of 90.24L/m²h, reflecting a 400% improvement over pristine PES membranes. Moreover, it exhibited excellent rejection rates of 97.21% for crystal violet (CV) and 99.43% for methylene blue (MB), alongside a rejection efficiency of 57.73% for the anionic dye methyl orange (MO). The antifouling performance was notably improved, as evidenced by an increase in the flux recovery ratio (FRR) from 46% for bare PES membranes to 81.11% for hybrid membranes. Additionally, the effects of various salt types on the membrane's separation performance were investigated. The Fe3O4@APC@MIL-101(Cr) modified PES membranes demonstrate significant potential as effective candidates for treating wastewater contaminated with dye pollutants.

Preferential Binding of Cations Modulates Electrostatically Driven Protein Aggregation and Disaggregation.

Protein aggregation resulting in either ordered amyloids or amorphous aggregates is not only restricted to deadly human diseases but also associated with biotechnological challenges encountered in the therapeutic and food industries. Elucidating the key structural determinants of protein aggregation is important to devise targeted inhibitory strategies, but it still remains a formidable task owing to the underlying hierarchy, stochasticity, and complexity associated with the self-assembly processes. Additionally, alterations in solution pH, salt types, and ionic strength modulate various noncovalent interactions, thus affecting the protein aggregation propensity and the aggregation kinetics. However, the molecular origin and a detailed understanding of the effects of weakly and strongly hydrated salts on protein aggregation and their plausible roles in the dissolution of aggregates remain elusive. In this study, using fluorescence and circular dichroism spectroscopy in combination with electron microscopy and light scattering techniques, we show that the ionic size, valency, and extent of hydration of cations play a crucial role in regulating the protein aggregation and disaggregation processes, which may elicit unique methods for governing the balance between protein self-assembly and disassembly.

A review of recent developments in the design of electrolytes and solid electrolyte interphase for lithium metal batteries

AbstractLithium metal batteries offer a promising solution for high density energy storage due to their high theoretical capacity and negative electrochemical potential. However, implementing of these batteries faces challenges related to electrolyte instability and the formation of a solid electrolyte interphase (SEI) on the lithium (Li) metal anode. The decomposition of liquid electrolytes leading to the creation of the SEI emphasizes the significance of the type of Li salt, solvent, and additives designed and used, as well as their interactions during the formation of the SEI. For practical applications, ensuring both the reversibility of the Li metal anode and electrolyte stability at high voltages is crucial. In this review, we explore recent advancements in addressing these challenges through new designs of electrolytes and SEI engineering practices. Specifically, we investigate the effects of electrolyte systems, including carbonate‐based and ether‐based solutions, along with modifications to these electrolyte systems aimed at achieving a more stable interface with the Li metal anode. Additionally, we discuss various artificial SEI structures based on organic and inorganic components. By critically examining recent research in these areas, this review provides valuable insights into current state‐of‐the‐art strategies for enhancing the performance and safety of Li metal batteries.image

Evaluation of Polymer Inclusion Membrane Containing Copoly Eugenol Divinyl Benzene 10% as a Carrier for Phenol Transport

Phenol is a toxic and organic compound that often contaminates water, posing significant environmental hazards. To resolve this issue, we conducted research on phenol transport using the Polymer Inclusion Membrane (PIM) method, employing Copoly Eugenol Divinyl Benzene (Co-EDVB) 10% as a carrier compound. The primary objective of this research was to assess the stability and capability of the PIM membrane. Our findings revealed that membrane stability was achieved with a plasticizer concentration of 3.32%. The addition of NaNO3 salt to the source phase yielded the most promising outcomes compared to other types of salt, facilitating the transport of 85.84% of phenol. When NaNO3 0.01 M was introduced in both the source and receiving phases, the transport efficiency increased to 89.93% and 86.76%, respectively. In order to evaluate the durability of the PIM membrane during repeated use, transportation experiments were conducted five times. Without washing, the membrane successfully transported phenol in amounts of 72.19%, 69.23%, 62.71%, 55.91%, and 48.16% during each successive run. Conversely, with regular washing, the membrane maintained its transport efficiency, achieving 70.85%, 64.10%, 56.72%, 49.26%, and 27.19% for each cycle. Notably, the membrane's lifetime reached only 29 days without the addition of 0.1 M NaNO3 salt. However, with the inclusion of NaNO3 0.1 M salt, its longer extended to 58 days.

Application of salt-assisted liquid extraction in bioanalytical methods

This review provides a comprehensive analysis of bioanalytical methods employed for the quantification of drug molecules in various biological matrices, including human plasma, urine, breast milk, and mouse plasma. The study not only examines traditional sample preparation techniques such as protein precipitation (PP), liquid-liquid extraction (LLE), and solid-phase extraction (SPE), but also delves into the relatively new and innovative salting-assisted liquid-liquid extraction (SALLE). It offers a thorough comparison of analytical methods utilizing SALLE, focusing on key parameters such as analysis time, calibration range, and the type and quantity of salts and organic solvents used. This review aims to serve as an essential resource for researchers and practitioners in selecting the most suitable bioanalytical methods for pharmacokinetic studies and drug monitoring, ultimately enhancing data quality and analytical efficiency in both clinical and research settings.

Quaternary Ammonium Salt-Based Intrinsic Antibacterial Polyurethanes: Optimizing the Antibacterial Activity via Cationic Main- or Side-Chain Design in Hard Segments.

Thermoplastic polyurethanes (TPUs) are one of the most appealing materials with extensive applications in biomedical fields due to their versatile mechanical properties and excellent biocompatibility. In response to the escalating challenges of bacterial infections, it is desirable to obtain TPUs with intrinsic antibacterial activity, particularly for application in biomedical devices and public places. Herein, a cationic main-/side-chain structure regulation strategy in the TPU hard segment was adopted to introduce and optimize the antibacterial activity. This was achieved by synthesizing two types of quaternary ammonium salts (QAS)-containing chain extenders, i.e., N-methyl-N-alkyl-N,N-bis(2-hydroxyethyl) ammonium bromide (Mn, where n represents the N-alkyl chain length) and N,N-dimethyl-N-alkyl-N-2,3-propylene glycol (Dn), from N-methyldiethanolamine (MDEA) and 3-dimethylamino-1,2-propanediol (DMAD), respectively. Given the structural differences between Mn and Dn, main-chain-type PU-Mn and side-chain-type PU-Dn were subsequently obtained with QAS groups in the hard segment. The N-alkyl chain length, QAS content, and main-/side-chain types were systematically investigated to optimize bactericidal properties. The results revealed that a long N-alkyl chain (from C6 to C14) increased the antibacterial activity of the chain extenders and corresponding TPU films. Besides, side-chain-type PU-Dn films showed higher contact-active antibacterial activity than that exerted by the main-chain-type PU-Mn films. Remarkably, almost 100% of Staphylococcus aureus(S. aureus) could be killed by the PU-D14 film with a low QAS content (1.6 wt %). All the TPUs showed good thermal stability with a degradation temperature of 5% mass loss (Td,5%) above 300 °C. Moreover, the TPU films displayed excellent mechanical properties with the tensile strength at break varying from 20.7 to 47.5 MPa and ultimate elongation above 1000%. All of the intrinsic antibacterial films showed negligible hemolytic activities.

Food Supplements Containing Iron-Comparison of Actual Content with Declared Content and Health Consequences.

The use of food supplements (FSs) is becoming an increasingly common trend observed in society. This is related to frequently observed nutritional deficiencies and the inability to provide sufficient amounts of nutrients, including vitamins and minerals, through the diet. The ease of registering FSs sometimes results in low-quality preparations on the market. Therefore, our research aimed to assess the content of one of the most popular trace element components, iron (Fe), in FSs available in Poland. This study covered 109 preparations purchased from stationary pharmacies and online pharmacies. The following criteria were used to characterize FSs in the data analysis: the Fe content declared by the manufacturer, pharmaceutical form, type of Fe salt, manufacturer's country of origin, contents of other trace elements or minerals, presence of additional ingredients, age of the target group, and addition of vitamins B2, B6, B12, and C. The Fe content was quantified using atomic absorption spectrometry after mineralization using microwaves. It was demonstrated that 69.73% of the preparations contained more Fe than the value declared by the manufacturer (and corrected for permissible deviations), 11.00% contained less Fe than declared, and only 19.27% were within the norm. In summary, the FS market requires the improvement of manufacturing processes and increased control, which should translate into patient safety.

Purification effect of pyrolyzed filler on the flammability of polylactide matrix

Abstract Research efforts are underway around the world to develop efficient recycling of the continuous phase of polymer composites toward reuse. It has already been demonstrated that pyrolyzed filler (PF) can be successfully used as a flame retardant for synthetic polyesters, including recycled ones. Therefore, the purpose of this work was to test the effect of PF on the flammability and thermal properties of the biopolyester phase. For this purpose, the pyrolysis technique was used, which yields a valuable solid phase in addition to the gas and liquid phases. To effectively give it a second life, a proprietary method of modifying the filler recovered by pyrolysis was developed to effectively separate and remove an organic part in the form of a layer of amorphous carbon (a-C), which acts as a universal sorbent. For this purpose, the a-C phase was extracted using binary solvent and replaced it using three types of salts: ammonium salt of benzyl phosphite, 1-butyl-3-methylimidazolium chloride (BMIC), and methyldodecylbenzyl trimethyl ammonium chloride (BMAC). Using a high-temperature processing technique, polylactide composites containing 5% (by weight) additive were obtained. The results of thermal (TGA, DSC) and flammability (PCFC, UL94, LOI) analysis studies show that the use of BMIC and BMAC salts for the intended purpose is particularly promising. The thermal stability of PLA composites containing SF-BMIC and SF-BMAC increased by 30 K and the flammability decreased by 23%. These promising results have opened up new avenues of research toward the synthesis of bio-flame retardants dedicated specifically to polylactide. Graphical abstract

A Randomized Crossover Trial of Acceptability of Quadruple-Fortified Salt in Women and their Households in Southern India

BackgroundDouble-fortified salt (DFS; iron, iodine) improved iron status in randomized trials and was incorporated into India’s social safety net programs, suggesting opportunities to address other micronutrient deficiencies. ObjectivesTo evaluate acceptability of quadruple-fortified salt (QFS; iron, iodine, folic acid, vitamin B12) in women and their households, using a randomized crossover trial design and triangle tests. MethodsWomen 18-49y (n=77) and their households were randomized to receive QFS or DFS in a randomized crossover design over a 3-week period (week 1: QFS/DFS, 2: iodized salt, 3: DFS/QFS). Each week, participants completed a 9-point hedonic questionnaire (1=dislike extremely to 9=like extremely) to evaluate five sensory domains (color, odor, taste, texture, overall acceptability) of the intervention, and remaining salt was weighed using a digital scale. Triangle tests were conducted among women to evaluate sensory discrimination of salt consumed in rice dishes prepared using standardized recipes. Mixed models were used to examine hedonic ratings and salt use; salt type, sequence, and period were included as fixed effects, and household was included as a random effect. Binomial tests were used to evaluate sensory discrimination of salt type in triangle tests. ResultsMean hedonic ratings for most of the five sensory domains were ≥7 (like moderately) and did not differ by salt type (overall acceptability mean [SD]: QFS: 7.8 [0.7] vs. DFS: 7.7 [1.2]; p=0.68). Household salt use (weighed) did not differ by salt type. During the 3-week intervention period, weighed salt use and hedonic ratings significantly increased, indicating a period effect independent of salt type or sequence. In triangle tests, rice samples prepared with QFS, DFS, or iodized salt were not distinguishable. ConclusionAcceptability of QFS was high, based on individual hedonic ratings and weighed household salt use. Rice dishes prepared with DFS, QFS, and iodized salt were not distinguishable. Findings informed the design of a randomized trial of QFS in this population. Registration numbersNCT03853304 and REF/2019/03/024479.

Phase behavior of aqueous two-phase systems formed with cholinium-based magnetic ionic liquids: Experimental insights and theoretical correlations

In this work, three cholinium-based MILs were synthesized, characterized and successfully applied to construct the magnetically responsive aqueous two-phase system (ATPs). This ATPs combined the advantages of ILs and magnetic responsiveness, and showed great potential in the field of extraction and separation. Phase behavior for the magnetic ionic liquid aqueous two-phase systems (MIL-ATPSs) containing [N 1 1n 2OH] [TEMPO-OSO3] + salts + water was investigated experimentally at different temperatures. Merchuk equation was adopted to fit the experimental binodal data with satisfactory correlation performances. The effects of the structure of MILs, temperature and types of salts on the phase behavior were evaluated. Investigation on the phase separation mechanism showed that the phase formation was affected by the structure and viscosity of MILs. The salting-out effect is recognized as the major force for phase separation, which is closely related to the Gibbs free energy of hydration (ΔhydG) and entropy of hydration (ΔhydS) of salts. In addition, a larger biphasic area was obtained by increasing the temperature, indicating the phase separation process was endothermic and entropically driven. The binodal curve at different temperature confirms that this MIL-ATPs has low critical solution temperature (LCST) phase transition behavior. All these experimentally measured data and the theoretical correlations can provide meaningful and valuable information that may promote further research and application.

Anticancer effects of washed-dehydrated solar salt doenjang and its metabolites

AbstractIn this study, the anticancer effect of doenjang according to the type of salt was investigated. Three samples were prepared: doenjang made with purified salt, doenjang made with generally manufactured solar salt, and doenjang made with washed and dehydrated solar salt (WDSD). In mice in which colon cancer was induced with azoxymethane/dextran sodium sulfate, doenjang made with solar salt, especially doenjang made with washed and dehydrated solar salt, was found to have a much higher colon cancer inhibition effect. WDSD significantly promoted the mRNA expression of apoptosis-related factors such as Bcl-2–associated X protein (Bax) and caspase 9 and the cell cycle arrest-related factors p53 and p21, and conversely significantly reduced the mRNA expression of apoptosis inhibitors such as B-cell lymphoma-2 (Bcl-2) (p < 0.05). Additionally, metabolites were investigated to determine which substances in WDSD exhibit this anticancer effect. As a result, the contents of isoflavone and soyasaponin B in the form of aglycons such as genistein, daidzein, and glycitein, which are known to have anticancer and anti-inflammatory properties, were found to be significantly high. Therefore, the results confirmed that doenjang prepared with washed and dehydrated solar salt has superior anticancer potential against colon cancer, and that various active ingredients contribute to the improvement of this functionality.

3D Printing of Tough Hydrogel Scaffolds with Functional Surface Structures for Tissue Regeneration.

Hydrogel scaffolds have numerous potential applications in the tissue engineering field. However, tough hydrogel scaffolds implanted in vivo are seldom reported because it is difficult to balance biocompatibility and high mechanical properties. Inspired by Chinese ramen, we propose a universal fabricating method (printing-P, training-T, cross-linking-C, PTC & PCT) for tough hydrogel scaffolds to fill this gap. First, 3D printing fabricates a hydrogel scaffold with desired structures (P). Then, the scaffold could have extraordinarily high mechanical properties and functional surface structure by cycle mechanical training with salting-out assistance (T). Finally, the training results are fixed by photo-cross-linking processing (C). The tough gelatin hydrogel scaffolds exhibit excellent tensile strength of 6.66MPa (622-fold untreated) and have excellent biocompatibility. Furthermore, this scaffold possesses functional surface structures from nanometer to micron to millimeter, which can efficiently induce directional cell growth. Interestingly, this strategy can produce bionic human tissue with mechanical properties of 10kPa-10MPa by changing the type of salt, and many hydrogels, such as gelatin and silk, could be improved with PTC or PCT strategies. Animal experiments show that this scaffold can effectively promote the new generation of muscle fibers, blood vessels, and nerves within 4weeks, prompting the rapid regeneration of large-volume muscle loss injuries.

Isotropic compression behavior of salinized unsaturated agricultural soil: An experimental and constitutive investigation

Salinity-induced soil degradation is a significant challenge in coastal reclamation areas, impacting agricultural productivity and infrastructure development. Variations in soil compression and deformation caused by changes in salinity warrant further investigation, particularly for agricultural applications. This study explores the relationship between soil pore water salinity and compressibility by conducting isotropic compression tests on salinized unsaturated agricultural soils treated with distilled water, 0.5 mol/L and 1 mol/L sodium chloride (NaCl) and calcium chloride (CaCl2) solutions. The results demonstrate that the type and concentration of salts significantly affect the compression behavior of these soils. The constitutive parameters were calibrated based on the experimental data. To account for osmotic suction, Barcelona Basic Model (BBM) was adjusted. The findings indicate that as pore water salinity increases, soil compressibility decreases, reflected by a compression index (Cc), and higher pre-consolidation stress (py). This modification aimed to quantify the impact of pore water salinity on soil compression. To validate the constitutive model, a numerical analysis of an isotropic compression test was carried out. This study contributes to our understanding of the isotropic compression behavior of coastal saline soil, proposes a constitutive framework for predicting soil responses under different salt conditions, and provides theoretical support for engineering construction in coastal reclamation areas.

Molecular Dynamics Simulation of Membrane Distillation for Different Salt Solutions in Nanopores.

Nanoporous membranes offer significant advantages in direct contact membrane distillation applications due to their high flux and strong resistance to wetting. This study employs molecular dynamics simulations to explore the performance of membrane distillation in a single nanopore, mainly focusing on wetting behavior, liquid entry pressure, and membrane flux variations across different concentrations and types of salt solutions. The findings indicate that increasing the NaCl concentration enhances the wetting of membrane pores, thereby decreasing the entry pressure of the solution. However, at the same salt concentration, the differences in wetting and liquid entry pressure among various salts, including CaCl2, KCl, NaCl, and LiCl, are minimal. The presence of hydrated ions significantly reduces membrane flux. As the concentration of NaCl solutions increases, the number of hydrated ions rises, thereby lowering the membrane flux of the salt solution. Furthermore, the type of salt has a pronounced effect on the structure of hydrated ions. Solutions with Ca2+ and Li+ exhibit the smallest first-layer radius of hydrated ions. Under the same salt concentration, KCl solutions demonstrate the highest membrane distillation flux, while CaCl2 solutions show the lowest flux.

The Impact of Binary Salt Blends’ Composition on Their Thermophysical Properties for Innovative Heat Storage Materials

Heat storage is an emerging field of research, and, therefore, new materials with enhanced properties are being developed. Examples of phase change materials that provide high heat storage are inorganic salts and salt mixtures. They are commonly used for industrial applications due to their high operational temperature and latent heat. These parameters can be modified by combining different types of salts. This paper presents the experimental study of the impact of the composition of binary salts on their thermophysical properties. Unlike the literature data, this article provides a detailed analysis of the phase change process in both directions: solid–liquid and liquid–solid. The results indicate that the highest latent heat was observed for a 70% NaNO3 content in the NaNO3–KNO3 mixture. Therefore, when this salt is used for heat storage, the most favorable choice is a 70:30 ratio, which provides the highest heat storage density and the lowest phase transition temperature. In the case of the NaNO3–NaNO2 mixture, the highest value of latent heat occurs for a ratio of 80:20, resulting in phase transition temperatures of 267.0 °C for the solid–liquid transition, and 253.5 °C for the liquid–solid transition. For heat storage applications, it is recommended to use pure NaNO2 salt instead of the NaNO3–NaNO2 mixture.

The impact of inorganic salts on the ultrasonic degradation of contaminants: A review

This comprehensive review explores the interplay between inorganic salts and ultrasound-assisted degradation of various contaminants. The addition of salt to aqueous matrices has been attributed to increasing contaminant degradation via the salting-out effect. However, research investigating the impact of salt on degradation has yielded inconsistent results. This review incorporated degradation information from 44 studies organizing data according to compound class and ionic strength to analyze the impact of inorganic salts on cavitation bubble dynamics, contaminant behavior, radical species generation, and contaminant degradation. Frequency and salt type were assessed for potential roles in contaminant degradation. The analysis showed that high intensity ultrasound was most beneficial to degradation in salt solutions. Unexpectedly, hydrophilic compounds showed marked enhancement with increasing ionic strength while many hydrophobic compounds did not benefit as greatly. Based on the collected data and analysis, enhanced degradation in the presence of salt appears to be primarily radical-mediated rather than due to the salting-out effect. Finally, the analysis provides guidance for designing sonolytic reactors for contaminant degradation.

Unrevealing Lithium Repositioning in the Hallmarks of Cancer: Effects of Lithium Salts (LiCl and Li2CO3) in an In Vitro Cervical Cancer Model.

Lithium, a natural element, has been employed as a mental stabilizer in psychiatric treatments; however, some reports indicate it has an anticancer effect, prompting the consideration of repurposing lithium for cancer treatment. The potential anticancer use of lithium may depend on its form (salt type) and the type of cancer cells targeted. Little is known about the effects of Li2CO3 or LiCl on cancer cells, so we focused on exploring their effects on proliferation, apoptosis, migration, and cell cycle as part of the hallmarks of cancer. Firstly, we established the IC50 values on HeLa, SiHa, and HaCaT cells with LiCl and Li2CO3 and determined by crystal violet that cell proliferation was time-dependent in the three cell lines (IC50 values for LiCl were 23.43 mM for SiHa, 23.14 mM for HeLa, and 15.10 mM for HaCaT cells, while the IC50 values for Li2CO3 were 20.57 mM for SiHa, 11.52 mM for HeLa, and 10.52 mM for HaCaT cells.) Our findings indicate that Li2CO3 and LiCl induce DNA fragmentation and caspase-independent apoptosis, as shown by TUNEL, Western Blot, and Annexin V/IP assay by flow cytometry. Also, cell cycle analysis showed that LiCl and Li2CO3 arrested the cervical cancer cells at the G1 phase. Moreover, lithium salts displayed an anti-migratory effect on the three cell lines observed by the wound-healing assay. All these findings imply the viable anticancer effect of lithium salts by targeting several of the hallmarks of cancer.

Regeneration of conventional and emerging PFAS-selective anion exchange resins used to treat PFAS-contaminated waters

Anion exchange resins (AERs) have emerged as a promising separation technology to remediate PFAS-contaminated waters due to their improved selectivities and capacities in comparison to legacy activated carbon adsorbents. Presently, site managers choose between AER systems employing resins defined as being ‘regenerable’ with relatively low PFAS selectivity, and PFAS-selective resins that are marketed as ‘single-use’ media intended for disposal upon PFAS breakthrough. However, the potential for these highly-selective adsorbents to be regenerated and/or reused remains poorly characterized. This study presents a comprehensive evaluation of the efficacy of various regenerant solution constituents, mixtures, and operational considerations on the regenerability of both ‘regenerable’ and ‘PFAS-selective’ AERs that were loaded during a pilot treatment study of PFAS-contaminated groundwater. Batch screening of regenerant solution constituents found that both classes of resins may be effectively regenerated using combinations of salt brine and organic cosolvent, with high cosolvent fractions being necessary for PFAS-selective AERs. While neither brine-only nor solvent-only regenerant solutions led to effective PFAS desorption, the efficacy of regeneration with brine/cosolvent mixtures varied with salt type and cosolvent composition. Chloride salts outperformed sulfate and bicarbonate salts, cosolvent efficacy depended on the volume fraction and type used, and highly non-polar solutions led to optimal PFAS desorption. Continuous-flow regeneration experiments showed near-complete PFAS desorption from regenerable AERs using 10 bed volumes (BVs) of 70 % methanolic brine solutions, whereas PFAS-selective resins required more bed volumes (30) of brines with higher methanol content (90 %) or a more hydrophobic cosolvent (n-propanol); increasing regenerant empty-bed contact time had minimal effect on PFAS desorption. > 90 % methanol recovery from the resulting waste regenerant mixtures was accomplished with negligible PFAS contamination using distillation, leaving a minimal volume of a PFAS-concentrated still bottoms waste that may be further treated for PFAS destruction. Life cycle analyses revealed that groundwater treatment using PFAS-selective AERs operated in a regenerable mode have lower environmental impacts and costs than systems using conventional regenerable AERs, and lower treatment costs than systems operated using PFAS-selective resins in a single-use mode. Although counterintuitive, these findings stem from the fact that higher cosolvent requirements for regeneration of PFAS-selective resins lead to greater internal recycling of regenerant solutions and much lower volumes of residual waste still bottoms that require off-site incineration or disposal.