Single Salt Research Articles

The promoted photocatalytic performance of in-situ surface alkalinization of g-C3N4 for methylene blue and Cr(VI) in dye wastewater

In this paper, a series of surface-alkalinized graphitic phase carbon nitride (g-C3N4) were synthesized via a one-step strategy employing dicyandiamide as the precursor. The effects of single salts (KCl, NH4Cl) and complex salts (KCl with NH4Cl) on the morphological structure, compositional composition, optical properties, and photocatalytic performance of alkalized CN samples were investigated. The IR and XPS analyses revealed that new structural units, C≡N and (N)2C-OH, were formed in the CN structure, indicating that the surface alkalinization of g-C3N4 had been successful. After in-situ surface alkalinization, the energy band structure of CN was optimized, the light absorption range was widened, and the photocatalytic activity was enhanced. Among them, the compound salt alkalinized sample (CNK2.0) at twice the amount of KCl as dicyandiamide showed the most excellent photocatalytic degradation performance. Its degradation efficiency of methylene blue within 60 min could reach 83.39 %, which was 2.05 times higher than that of pure g-C3N4. With a 47.1 % reduction of Cr(VI) at 60 min, the CNK1.5 sample demonstrated the prime photocatalytic activity, which was 34.2 % higher than that of pure g-C3N4. The surface hydroxylation and the optimization of the energy band structure are the main reasons for the enhanced photocatalytic activity of carbon nitride after complex salt alkalinization.

Comparative Transcriptome Analysis Reveals the Molecular Mechanism of Salt Combined with Flooding Tolerance in Hybrid Willow (Salix matsudana × alba)

Plants in coastal areas often face the combined stress of salt and flooding, which can cause severe damage. The impact of multiple stresses on plant growth and survival is greater than that of individual stresses. However, the molecular responses of hybrid willow (Salix matsudana × alba) to the combination of salt and flooding have not been well understood. In this study, we conducted a comparative transcriptome analysis to investigate the molecular mechanism underlying the tolerance of hybrid willow to salt-flooding. Seedings were, respectively, treated with 200 mM NaCl and flooded with water or 200 mM NaCl solution for 3 d, 10 d, and 17 d. We identified 1842, 3350, and 2259 differentially expressed genes (DEGs) regulated by hybrid willow under single salt stress, single flooding stress, and combined salt and flooding stress, respectively. Many DEGs detected in single salt- and flooding-treated plants were expressed differentially after the combined salt and flooding. Most of the shared transcripts exhibited similar fold changes in common molecular responses such as detoxification of reactive oxygen species (ROS) and signaling pathways related to calcium, phytohormones, and protein kinases, which were also observed in plants exposed to each stress individually. Additionally, a large number of specific DEGs were identified under salt-flooding stress, primarily associated with cell wall remodeling, osmotic adjustments, stress signaling, primary metabolism, and ROS scavenging. KEGG (Kyoto Encyclopedia of Genes and Genomes) annotation indicated that hybrid willow leaves responded to salt-flooding stress mainly through phytohormone signaling and MAPK signaling pathways. Overall, this study provides new insights into the molecular mechanisms underlying the response of Salix species to multiple stresses and identifies potential candidate genes for enhancing the performance of hybrid willows.

Short-wave infrared position-sensitive detector enabled by lateral diffusion of thermalized carriers in lead salts

Position-sensitive detector (PSD) plays a vital role in various applications, such as motion tracking, pilotless automobile, laser radars, and precision machining. However, limited by the detection designs of the lateral photovoltaic effect and segmented sensors, the state-of-the-art PSD suffers from complicated architecture, slow response, and narrow waveband. Herein, we propose a conceptually distinct PSD operated in short-wave infrared (SWIR, 0.8–2.3 μm), an important optical communication waveband and atmosphere window, in single crystalline lead salts thin film. The SWIR PSD present self-driven (0 V bias), fast response (590 ns), and high position resolution (45.8 nm/Hz) with a position sensitivity of 257.8 mV/mm. By combining with the numerical simulation, the underlying physics of lateral thermalized carrier diffusion driven by temperature gradient is proposed to explain the ultrafast and high-resolved SWIR PSD. Finally, we demonstrate its applications in infrared target real-time tracking, indicating its great potential in infrared guidance, trajectory tracking, and microrobots.

A zero-thickness interface element incorporating hydro-chemo-mechanical coupling and rate-dependency

The interfaces play a key role in many engineering problems involving geologic materials. In particular, slope stability analyses of ancient landslides (that were subjected to large displacements along a slip surface) need the formulation of ad hoc interface elements. The mechanical response of slip surfaces in clays is affected by hydro-chemo-mechanical interactions and by rate effects and this paper presents the formulation of an innovative zero-thickness interface element for dealing with these kinds of effects. The proposed interface element is an extension of the modified zero-thickness element proposed by Goodman et al. (J Soil Mech Found Div ASCE 94:637–659, 1968). In addition to solid displacement, we consider the flow of water and the diffusion of a single salt in the fluid phase. Terzaghi’s effective stress principle is used leading to the usual hydro-mechanical coupling within the interface element. The fluxes of water and salt are considered in the longitudinal and in transversal directions of the interface element. For the constitutive relation, we propose an innovative nonlinear elastic energy that improves the numerical convergence in the occurrence of interface opening. The Mohr–Coulomb yield surface is used for the plastic regime in which we considered the effects of strain rate and salt concentration on the shearing behaviour of the interface element. The proposed element has been implemented in a user-defined subroutine of ABAQUS. The typical effects of salt concentration and displacement rate and the typical model responses for the longitudinal and transversal fluxes of salt and pore fluid are discussed in detail. Finally, the proposed interface element is validated through the comparison with experimental results.

Salt mixtures in stone weathering

Salt related weathering of stones has been attributed to pressures exerted by repeated cycles of crystallization within pores. Relative Humidity (RH) is a key driver for dissolution and crystallization processes. Despite the prevalence of salt mixtures in natural environments, most experimental work has focused on single salts. Thus, the identification of salt mixture composition and their behavior is necessary to understand weathering. Thermodynamic calculations are used to analyze several thousand realistic salt mixtures found in weathered stone. We identify two common mixture types and their behavior. From at least 85 salt species theoretically present, 14 common salts are identified that occur most frequently and their critical RH points are discussed. These findings have wide-reaching implications for understanding salt weathering processes and informing the design of experimental stone weathering research.

Hot corrosion mechanism and thermal cycling performance of air-plasma-sprayed LaYbZr2O7 thermal barrier coatings in the vanadate-containing molten salts

LaYbZr2O7 has been regarded as a promising thermal barrier coatings (TBC) material due to its excellent mechanical and thermal properties. In this study, the LaYbZr2O7 coating was prepared by atmospheric plasma spraying (APS), and its hot corrosion mechanism and thermal cycling performance in vanadate-containing molten salts (V2O5 and Na2SO4 + V2O5) were investigated. Results indicated the hot corrosion reaction of LaYbZr2O7 coatings in molten V2O5 was temperature dependent, attributed to the thermal decomposition of ZrV2O7 above 800 °C. A continuous dense corrosion layer could form on the top surface of LaYbZr2O7 coatings after hot corrosion in molten V2O5 salt, effectively preventing the further penetration of molten salt. However, the dense corrosion layer could not form when exposed to Na2SO4 + V2O5 molten salts at 1000 °C, since the formation of NaVO3 could improve the mobility of molten salts and slow the precipitation reaction rate of corrosion products. Furthermore, thermal cycling tests indicated that the Na2SO4 + V2O5 mixture could be more detrimental to LaYbZr2O7 coatings than single V2O5 salt, and the dense corrosion layer could act as a sacrifice layer to protect the inner coating from corrosion degradation. The hot corrosion mechanism of LaYbZr2O7 was discussed in detail based on the Lewis acid-base and dissolution-precipitation rule.

Dynamics of SLC25A51 reveal preference for oxidized NAD+ and substrate led transport.

SLC25A51 is a member of the mitochondrial carrier family (MCF) but lacks key residues that contribute to the mechanism of other nucleotide MCF transporters. Thus, how SLC25A51 transports NAD+ across the inner mitochondrial membrane remains unclear. To elucidate its mechanism, we use Molecular Dynamics simulations to reconstitute SLC25A51 homology models into lipid bilayers and to generate hypotheses to test. We observe spontaneous binding of cardiolipin phospholipids to three distinct sites on the exterior of SLC25A51's central pore and find that mutation of these sites impairs cardiolipin binding and transporter activity. We also observe that stable formation of the required matrix gate is controlled by a single salt bridge. We identify binding sites in SLC25A51 for NAD+ and show that its selectivity for NAD+ is guided by an electrostatic interaction between the charged nicotinamide ring in the ligand and a negatively charged patch in the pore. In turn, interaction of NAD+ with interior residue E132 guides the ligand to dynamically engage and weaken the salt bridge gate, representing a ligand-induced initiation of transport.

Evaluating the role of salts on wettability alteration in dolomite rocks: Possibility of water based oil mobilization application

While many low salinity studies have been conducted on chalks, calcite minerals and sandstone rocks, few research articles have explored the same for applications in dolomite rocks. To explore the effect of mineralogy, a comparative study on the wettability alteration in the presence of low salinity brines for 2 carbonate rocks of varying composition was studied. The contact-angle experiments were performed for two carbonate samples. One carbonate sample was composed of ∼100 % dolomite mineral whereas the other carbonate rock sample was composed of both dolomite and calcite mineral (5 % calcite and 95 % dolomite). The ionic solutions were composed of NaCl, MgCl2, CaCl2 and CaSO4 single salt solutions of concentration (500 ppm to 5000 ppm). The contact angle reduction was observed in the following order CaSO4 > MgCl2 > CaCl2 > NaCl for the carbonate sample containing calcite and dolomite minerals and the maximum reduction in contact angle for the carbonate sample containing dolomite and calcite minerals was observed for CaSO4 brines was 26.13 % for 1000 ppm concentration. The contact angle reduction observed for the carbonate sample containing dolomite mineral was found to be in the following order MgCl2 > CaCl2 > CaSO4 > NaCl and the maximum reduction in contact angle was observed for MgCl2 brines was 24.58 % for 3000 ppm concentration. The wettability alteration observed in the carbonate sample containing dolomite mineral was less as compared to the carbonate sample containing calcite and dolomite mineral. In the presence of MgCl2 brines, the pH of the brines dominates the mineral dissolution, thereby improving or reducing the extent of wettability alteration. However, the complete wettability reversal has not been observed in this study. An increase in temperature (from 70 to 90 °C) was found to be favourable for wettability alteration while the presence of calcites, along with dolomites has the potential to further improve oil recovery.

Study on the Permeability of GCL Materials in Coupled Environment

As a new-type anti-seepage material, Geosynthetic Clay Liner (hereinafter referred to as GCL) has been applied in various anti-seepage projects and achieved good benefits. Based on different salt solution types, concentrations, dry-wet, and freeze-thaw cycles, this paper designs a permeability test of GCL after aging, and the result shows that: (1) under the influencing factors of single salt solution, there is a threshold concentration of 0.15 mol/L, which means that the increase rate of GCL permeability coefficient suffers a significant decrease above this concentration. (2) With fewer numbers (<4 ) of dry-wet cycles the GCL permeability coefficient shows faster growth and then returns gradually to stability. (3) Compared with dry-wet and freeze-thaw environments, cation concentration and valence have a more prominent inhibition effect on the anti-seepage property of GCL. The research results can provide data reference and reasonable advice for the deterioration of various indicators of GCL material and its service life in corresponding projects in saline soil areas.

Thermodynamic Model of the Fluid System H2O–CO2–NaCl–CaCl2 at P-T Parameters of the Middle and Lower Crust

Based on the earlier obtained equations of state for the ternary systems H2O–CO2–CaCl2 and H2O–CO2–NaCl, an equation of state for the four-component fluid system H2O–CO2–NaCl–CaCl2 is derived in terms of the Gibbs excess free energy. A corresponding numerical thermodynamic model is built. The main part of the numerical parameters of the model coincides with the corresponding parameters of the ternary systems. The NaCl–CaCl2 interaction parameter was obtained from the experimental liquidus of the salt mixture. Similar to the thermodynamic models for H2O–CO2–CaCl2 and H2O–CO2–NaCl, the range of applicability of the model is pressure 1–20 kbar and temperature from 500 to 1400°C. The model makes it possible to predict the physicochemical properties of the fluid involved in most processes of deep petrogenesis: the phase state of the system (homogeneous or multiphase fluid, presence or absence of solid salts), chemical activities of the components, densities of the fluid phases, and concentrations of the components in the coexisting phases. The model was used for a detailed study of the phase state and activity of water on the H2O–CO2–salt sections when changing the ratio {{{{x}_{{{text{NaCl}}}}}} mathord{left/ {vphantom {{{{x}_{{{text{NaCl}}}}}} {({{x}_{{{text{NaCl}}}}} + {{x}_{{{text{CaC}}{{{text{l}}}_{{text{2}}}}}}})}}} right. kern-0em} {({{x}_{{{text{NaCl}}}}} + {{x}_{{{text{CaC}}{{{text{l}}}_{{text{2}}}}}}})}} from 1 to 0. Changes in the composition and density of coexisting fluid phases at a constant activity of water and changes in the total composition of the system are studied. A set of phase diagrams on sections H2O–NaCl–CaCl2 for different mole fractions of CO2 is obtained. Pressure dependencies of the maximal activity of water in the field of coexisting unmixable fluid phases are obtained for several salt compositions of the system. Due to removal of restrictions resulting from a smaller number of components in ternary systems, the thermodynamic behavior of systems with a mixed composition of the salt significantly differs from the behavior of those with a single salt component.

Investigation on the bond characteristics and microwave dielectric properties of rock salt-structured Li2Mg0.5nTiO3+0.5n (n = 1–8) ceramics based on the complex chemical bond theory

Cubic rock salt structured ceramics are of great interest due to their outstanding microwave dielectric properties. Complex chemical bond theory and polarization theory combined with XRD refinement as well as XPS were employed to reveal the mechanisms of the compositional effect on the microwave dielectric properties of Li2Mg0.5nTiO3+0.5n ceramics with a rock salt structure. It was demonstrated that when n = 1, the microwave dielectric properties exhibit a biphasic structure. However, as n increased to 2 and higher levels, the specimens were consisted of a single cubic rock salt phase. εr of single-phased samples decreased with an increase in the n value, which was due to the decreases in both the bond ionicity and polarizability of unit cell. Meanwhile, as lattice energy increased, the formation of oxygen vacancies was effectively suppressed, and anharmonic lattice vibrations were weakened, leading to an increase in Q×f. Moreover, τf showed a negative shift due to an increase in the aL,ave of the chemical bond and an decrease in the bond energy. The optimal microwave dielectric properties of εr= 17.3, Q×f= 81,000 GHz, and τf = −7.7 ppm/℃ were achieved in the component with n = 1 when sintered at 1350 °C for 4 h.

Eco‐Friendly Tetrahydropyran Enables Weakly Solvating “4S” Electrolytes for Lithium‐Metal Batteries

AbstractThe growth of lithium dendrites hinders the commercial applications of lithium‐metal batteries. Electrolytes play a crucial role in influencing electrode/electrolyte interfacial chemistry. Traditional electrolytes adopt strongly solvating solvents to dissolve Li salts, creating an organic‐rich solid electrolyte interface (SEI). The Li+ conductivity and mechanical strength of the organic‐rich SEI are poor, so the derived SEI cannot effectively suppress the growth of Li dendrites. The weakly solvating electrolyte (WSE) system can realize an inorganic‐rich SEI, demonstrating improved compatibility with the Li metal. However, the design rules for the WSE are not clear. Here, four kinds of “4S” (single salt and single solvent) WSE are designed to investigate interface chemistry. The SEI thickness, pore volume, and porosity are revealed via a reactive force field. The results show the heterocyclic and symmetric tetrahydropyran has the most suitable solvating power and the best interfacial stability in the lithium‐metal battery system. This research provides a weakly solvating electrolyte design route for bridging the molecular thermodynamic and interfacial chemistry gap.

Thermodynamic Model of the Fluid System H&lt;sub&gt;2&lt;/sub&gt;O–CO&lt;sub&gt;2&lt;/sub&gt;–NaCl–CaCl&lt;sub&gt;2&lt;/sub&gt; at &lt;i&gt;P-T&lt;/i&gt; Parameters of the Middle and Lower Crust

Based on the earlier obtained equations of state for the ternary systems H2O–CO2–CaCl2 and H2O–CO2–NaCl, an equation of state for the four-component fluid system H2O–CO2–NaCl–CaCl2 is derived in terms of the Gibbs excess free energy. A corresponding numerical thermodynamic model is build. The main part of the numerical parameters of the model coincides with the corresponding parameters of the ternary systems. The NaCl–CaCl2 interaction parameter was obtained from the experimental liquidus of the salt mixture. Similar to the thermodynamic models for H2O–CO2–CaCl2 and H2O–CO2–NaCl, the range of applicability of the model is pressure 1–20 kbar and temperature from 500°C to 1400°C. The model makes it possible to predict the physicochemical properties of the fluid involved in most processes of deep petrogenesis: the phase state of the system (homogeneous or multiphase fluid, presence or absence of solid salts), chemical activities of the components, densities of the fluid phases, and concentrations of the components in the coexisting phases. The model was used for a detailed study of the phase state and activity of water on the H2O–CO2–salt sections when changing the ratio \( {{{{x}_{{{\text{NaCl}}}}}} \mathord{\left/ {\vphantom {{{{x}_{{{\text{NaCl}}}}}} {\left( {{{x}_{{{\text{NaCl}}}}} + {{x}_{{{\text{CaC}}{{{\text{l}}}_{{\text{2}}}}}}}} \right)}}} \right.} {\left( {{{x}_{{{\text{NaCl}}}}} + {{x}_{{{\text{CaC}}{{{\text{l}}}_{{\text{2}}}}}}}} \right)}} \) from 1 to 0. Changes in the composition and density of coexisting fluid phases at a constant activity of water and changes in the total composition of the system are studied. A set of phase diagrams on sections H2O–NaCl–CaCl2 for different mole fractions of CO2 is obtained. Pressure dependencies of the maximal activity of water in the field of coexisting unmixable fluid phases are obtained for several salt compositions of the system. Due to removal of restrictions resulting from a smaller number of components in ternary systems, the thermodynamic behavior of systems with a mixed composition of the salt is significantly differ from the behavior of those with a single salt component.

Sensing System for Mixed Inorganic Salt Solution Based on Improved Double Label Coupling RFID

As a crucial part in sewage, high-salt wastewater contains abundant corrosive components and heavy metal elements, which makes it difficult for invasive monitoring. Therefore, based on coupling Radio Frequency Identification(RFID) tags, this paper proposes a non-invasive monitoring method for concentration of inorganic salt in sewage. In this method, Cole-Cole model and Slit Cylindrical Capacitance(SCC) model are combined to explore the relationship between capacitance of RFID and concentration of inorganic salt in sewage pipeline. A New Efficient Levenberg-Marquardt(NELM) algorithm is used for regression between relative permittivity and concentration of inorganic salt categorically. Then, measurement data is processed under modified relative permittivity mixing rule of electrolyte and solvent. Finally the concentration of each component in the multi-component inorganic salt wastewater are obtained. Experimental results show that the maximal relative error (MRE) and average relative error(ARE) of single inorganic salt solution are 1.1% and 0.5%, while mixed solution are 2.6% and 1.89%. Such results indicate significant improvement comparing with previous works. Great potential of RFID in working sewage monitoring is sufficiently confirmed.

How to Choose Suitable Reference Electrode and Aqueous Electrolyte to Avoid Error in Electrochemical Measurements?

Objective: To reduce the experimental error, three commonly used reference electrodes (Hg/HgO, Hg/Hg2Cl2 (SCE), and Ag/AgCl) are investigated to select the appropriate electrode in different aqueous electrolytes. Methods: Besides, the correct electrochemical test method is proposed according to the stability of the reference electrode. After measuring the potential difference of reference electrode in various aqueous electrolytes, it is found that Hg/HgO electrode is suitable for alkaline electrolytes, with minimum deviation in 6 M KOH solution, SCE should be used in acidic electrolytes, with minimum deviation in H2SO4 solution less than 1 M, and both SCE and Ag/AgCl electrode can be used in neutral electrolytes. Results: Due to the liquid junction potential, the result of using the double salt bridge is more accurate than that of using the single salt bridge. Conclusion: The stability of various reference electrodes in electrolytes is discrepant. Therefore, calibration is emphasized since the potential of the reference electrode drifts and even becomes invalid after prolonged use.

Polyamide/UiO-66-NH2 nanocomposite membranes by polyphenol interfacial engineering for molybdenum(VI) removal

Introducing porous nanomaterials into polyamide thin layer has been identified to be a desirable approach to improve separation performance of nanofiltration membrane. In this work, a novel sandwich-like thin-film nanocomposite membrane (TFNi) featuring an interlayer was prepared. The interlayer, composed of porous UiO-66-NH2 metal organic framework and adhesive tannic acid (TA), was formed between amphiphilic poly(vinylidene fluoride)-grafting-poly(acrylic acid) substrate and polyamide top layer by self-assembly and interfacial polymerization. TFNis were characterized by FT-IR, SEM, AFM, XRD, water contact angle, zeta potential, molecular weight cut off, flux and ion retention. Results showed that the introduction of interlayer could enhance efficiently membrane flux and ion removal. TFNi-3 membrane constructed by an optimized stepwise deposition, had a high permeate flux (65.4 L m−2 h−1), and good removal efficiencies towards single molybdenum(VI) (Mo(VI)) (98.1 %), single salt (30.8 % for NaCl, 96.5 % for Na2SO4) and mixed solutions (37.0 % for NaCl-Mo(VI), 93.6 % for Na2SO4-Mo(VI), 76.1 % for NaCl-Na2SO4-Mo(VI)). The adsorption experiment and density functional theory (DFT) calculations were also carried out. Amino and zirconium oxygen clusters in UiO-66-NH2 and polyphenol in TA were main adsorption sites. In addition, TFNi-3 had the favorable stability. Perhaps it has a potential application for desalination and Mo(VI) removal from wastewaters.

Effect of Metakaolin on the Diffusion Properties of Chloride Ions in Cement Mortar under the Coupling Effect of Multiple Factors in Marine Environment

To address the problem of chloride ion transport in cement concrete in marine environment, this study investigates the effect of metakaolin dosage on the chloride ion diffusion resistance of mortar and its mechanism by testing the chloride ion binding capacity and microstructure of mortar under the coupling effect of chlorine salt-sulfate-carbonation multiple factors. The results show that the coupling of sulfate or carbonation reduces chloride ion transport to some extent compared with single chlorine salt attack, while the three-factor coupled environment promotes free chloride ion diffusion. This is because the products of calcium alumina, gypsum, and calcium carbonate grow together and compete with each other to form more large capillaries; thus, accelerating the diffusion of chloride ions in cement mortar. Metakaolin, due to its higher pozzolanic activity, increases the monocarbon aluminate content in the erosion products, promotes F-salt generation, and increases the Al/Si ratio, which strengthens the binding ability of C-S-H gel to chloride ions, so the free chloride ion concentration inside the specimens doped with metakaolin is lower. In particular, the three-factor coupled environment has less 0.05–10 μm capillary pore content and higher F-salt stability in the specimens, which has the strongest effect on chloride ion curing, and the free chloride ion concentration integral in M-SCCl is reduced by nearly 30% compared with MF-SCCl and F-SCCl.

Asymmetric polyelectrolyte multilayer nanofiltration membranes: Structural characterisation via transport phenomena

One promising application of polyelectrolyte multilayers (PEMs) is their use as selective layers in nanofiltration (NF). Especially encouraging are the simplicity of fabrication, controlled layer thickness in the nanometer range, and versatility. In addition to commonly used tuning parameters such as pH, ionic strength, and choice of polyelectrolytes, combining two different PEMs in a so-called asymmetric PEM enables further optimisation of the selective membrane layer. Experimental characterisation of these PEMs is complex, and therefore, the knowledge of the exact layer structure is limited. In this work, we combine filtration experiments and theoretical transport models to describe the effective structure of an asymmetric PEM made of a bottom layer of poly(allylamine hydrochloride) (PAH)/poly(sodium 4-styrenesulfonate) (PSS) and a top layer of PAH/poly(acrylic acid) (PAA). Obtained membrane properties suggest the formation of a distinct layer structure with individual layer properties close to the single symmetric PEM after a minimum number of layers. There is, however, a fundamental difference in the retention of salt and polyethylene glycol molecules. While salt retention properties of the asymmetric PEM are stable already after only one bilayer of PAH/PAA, a gradual transition in the retention of polyethylene glycol molecules from the more open PAH/PSS system to the dense PAH/PAA system is observed. This is attributed to the different exclusion mechanisms dominating solute transport (size- vs charge-based). A gradual decrease in molecular weight cut-off (MWCO) with increasing bilayer (BL) number of PAH/PAA is observed, resulting in a minimum MWCO of around 120g mol−1 after 5 BLs. Theoretical transport models assuming an ideal layer structure in series predict this value as well. At the same time, high mono- to divalent salt selectivity is observed after 1 BL of PAH/PAA already. Single salt retention of NaCl is around 20% versus Na2SO4, MgCl2 and MgSO4 being above 95%. Although this trend is qualitatively predicted by the theoretical transport model, again assuming ideal layers in series, deviations indicate variations in charge distribution within these layers.

The sustainable catalytic conversion of CO2 into value-added chemicals by using cobaloxime-based double complex salts as efficient and solvent-free catalysts

Cobalt(III)-based catalysts for CO2 fixation are widely applied for the synthesis of cyclic carbonates from epoxides and CO2 under suitable and solvent-free conditions. Inspired by the enhancing catalyst strategy for highly efficient CO2 conversion into useful products, here we show that the cobaloximes (1–3) and corresponding to different double cobaloxime salts (4–6), and their single salts with simple counterions (7–9) were prepared and evaluated as an efficient catalyst for the coupling of CO2 and epoxides into cyclic carbonates. The structure of synthesized target cobaloximes was characterized using a combination of 1H, 13C, and 11B NMR spectra, FT-IR spectra, UV–Vis spectra, LC-MS/MS spectrometers, melting point, and elemental analysis techniques. Although the prepared cobaloxime-based catalytic systems were studied in a wide range of epoxide substrates, the highest catalytic activity was observed in the conversion of epichlorohydrin under suitable conditions. After seeing highly efficient catalytic conversion and selectivity of the newly synthesized cobaloximes (1–3) and different cobaloxime-based double complex salts (4–9), the effect of epoxide, base, reaction time, temperature, and CO2 pressure was investigated for these catalysts. The best conversion was performed in the presence of a catalyst (6) (the double cobaloxime salt bearing 4-t-butyl) and DMAP as a co-catalyst, with a 98% yield and 99% selectivities.

Utilizing publicly available datasets for identifying offshore salt strata and developing salt caverns for hydrogen storage

Abstract Hydrogen is expected to play a key role in a future climate-neutral economy by decarbonizing ‘hard to abate’ sectors, and importantly act as an energy carrier to balance intermittent renewable energy production, which, if stored, could be used to address grid-scale energy demands. It is evident that for unlocking the vast potential of hydrogen technologies, large-scale hydrogen storage with the capability of fast cyclic operations needs to be secured. Underground salt caverns, where decades of operational experience exist, offer an attractive option for hydrogen storage due to the high hydrogen sealing potential of salt, capability for large injection/withdrawal flow rates and capacity for large volume storage. This study presents a novel methodology for selecting offshore salt cavern sites based on publicly available datasets, which leads to eventually estimating regional hydrogen storage capacities. The Southern North Sea was investigated and a case study detailing a single diapiric salt structure is presented, demonstrating the strength and practicality of the framework as well as highlighting the potential of offshore salt cavern storage of hydrogen in the decarbonization energy journey of the UK.