Chloride Transport Research Articles

Constructing in-situ polymerized electrolyte for room-temperature solid-state chloride ion battery with enhanced electrochemical performance

Considering large volume variation and dissolution issues of some promising electrode materials for chloride ion batteries (CIB), the construction of solid polymer electrolytes (SPE) for efficient chloride ion transport is intriguing. However, this is hindered by low ionic conductivity of chloride SPEs and poor cycling performance of CIBs. Herein, an in-situ polymerized and cross-linked poly(ethylene glycol) diacrylate-based chloride SPE with a low plasticizer content of succinonitrile is designed, yielding a room-temperature ionic conductivity of 7.6 × 10−5 S cm−1, which is higher than that of previously reported SPEs for CIBs. Moreover, the use of the as-prepared SPE achieves an integrated organic cathode with significantly enhanced rate performance and capacity retention of 96.1 % after 100 cycles at room temperature, which is much higher than 49.9 % (80 cycles) of the cathode in the CIB with a sandwiched structure. These improved properties are also superior to that of other reported cathodes coupled with different chloride SPEs. The chloride ion transfer mechanism of the cathode is revealed by X-ray photoelectron spectroscopy and energy dispersive spectroscopy.

Structure and corrosion properties of multilayer metal/nitride/oxide ceramic coatings formed on austenitic-martensitic steel by magnetron deposition

The design of protective coatings preventing the degradation and failure of austenitic steels in humid climate is a relevant issue. In this work, a conventional magnetron sputtering method was utilized in order to fabricate a four-layer Ni/Al-Si-N/Ni/Al-Si-O coating onto austenitic-martensitic steel. At the first stage of deposition, a three-layer coating was formed in an Ar+N2 atmosphere using a mosaic target (Ni or Al-Si), while the second stage included the deposition of the outer ceramic Al-Si-O layer in an Ar+O2 gas mixture. The studies of the structure, hardness, adhesion strength and electrochemical behavior (in 3.5 wt.% NaCl) of the «coating/steel» system were performed by means of X-ray Diffraction, electron microscopy, mechanical (indentation and scratch) tests and electrochemical impedance spectroscopy. The ceramic Al-Si-O layer exhibits an amorphous structure. The adjacent nickel layers have submicrocrystalline columnar grains. The ceramic Al-Si-N layer possesses a nanocrystalline columnar structure based on AlN + Si3N4 phases. Hardness behavior of the multilayer coating varies nonmonotonically due to a contribution of the soft amorphous phase in the upper surface layer and high-strength nanocrystalline phases in the underlying sublayers. It has been revealed that as-deposited multilayer coating decreases a corrosion rate of the substrate. The layered structure of the coating hinders the transport and diffusion of chloride ions to the substrate and decreases the corrosion rate of the substrate. However, a transport of chloride ions into the inner layers of the coating may occur through the microstructural defects preserved in the amorphous Al-Si-O layer. The scheme describing an initiation of corrosion damage and formation of corrosion products under critical corrosion conditions was proposed.

Similarity analysis of chloride transport behavior in fly ash concrete under different environments aiding by machine learning method

To forecast chloride transport in site by applying accelerated test results, it is necessary to investigate the similarity of chloride diffusivity under different environments. However, limited by test period and cost expenses, a large amount of tests in field and simulated environment are hard to conduct, and a limit test data will make prediction on chloride diffusivity of concrete less precise. To solve this problem, machine learning methods are explored to predict chloride transport. Based on the existing chloride concentration test data of fly ash concrete in natural and accelerated simulated environment, this paper establishes a chloride concentration predictive model based on the one-dimensional convolutional neural network (1D-CNN) method at first, and verifies the stability and accuracy of the established model. Second, similarity models for concentration ratio and diffusion time ratio based on multivariate nonlinear model and based on theoretical Fick’s second law are constructed, and the model accuracy is also tested. Finally, the chloride concentration data predicted by the 1D-CNN model is applied to the constructed similarity models respectively, and the application results are compared and analyzed to determine the optimal similarity model. Results indicate that the concentration predicted by the 1D-CNN method has a strong robustness and a small prediction error. Besides, based on multivariate nonlinear model, the error of concentration predicted by the similarity models for concentration ratio and diffusion time ratio is less than 16 % and 30 %, respectively. Similarly, according to the theoretical model based on Fick’s second law, the error of concentration predicted by the similarity models for concentration ratio based on the time dependent chloride diffusion coefficient and time dependent peak chloride concentration is less than 21 % and 36 %, respectively. The similarity model for concentration ratio based on multivariate nonlinear model has the best prediction effect.

High correlated color temperature artificial lighting impairs retinal pigment epithelium integrity and chloride ion transport: A potential mechanism for choroidal thinning

Among the environmental factors contributing to myopia, the role of correlated color temperature (CCT) of ambient light emerges as a key element warranting in-depth investigation. The choroid, a highly vascularized and dynamic structure, often undergoes thinning during the progression of myopia, though the precise mechanism remains elusive. The retinal pigment epithelium (RPE), the outermost layer of the retina, plays a pivotal role in regulating the transport of ion and fluid between the subretinal space and the choroid. A hypothesis suggests that variations in choroidal thickness (ChT) may be modulated by transepithelial fluid movement across the RPE. Our experimental results demonstrate that high CCT illumination significantly compromised the integrity of tight junctions in the RPE and disrupted chloride ion transport. This functional impairment of the RPE may lead to a reduction in fluid transfer across the RPE, consequently resulting in choroidal thinning and potentially accelerating axial elongation. Our findings provide support for the crucial role of the RPE in regulating ChT. Furthermore, we emphasize the potential hazards posed by high CCT artificial illumination on the RPE, the choroid, and refractive development, underscoring the importance of developing eye-friendly artificial light sources to aid in the prevention and control of myopia.

High-Frequency Data Provides Insight into Chloride Transport Pathways and Exceedances of Chronic Chloride Guidelines for the Protection of Aquatic Life in Streams Impacted by Deicers

High-Frequency Data Provides Insight into Chloride Transport Pathways and Exceedances of Chronic Chloride Guidelines for the Protection of Aquatic Life in Streams Impacted by Deicers

Enhanced subsurface chloride transport resistance of cement pastes via optimizing CO2 curing time

The chloride erosion of CO2 cured cementitious materials could be a concern for concrete structure application. This study aims to clarify the chloride transport and binding behavior by elucidating the alteration of free and bound chloride content from the outer towards the core (5 layers with 2 mm intervals). The carbonation depth and chloride binding ratio at the carbonation zone were also determined. The results showed that dense carbonated surface significantly reduced the penetration of chloride, especially in the carbonation zone, resulting in a decrease in total chloride content (48 %–83 %) and a slight increase in the chloride binding ratio (up to 22 %). It is found that the benefits of minimizing surface porosity to impede chloride penetration significantly outweigh the drawbacks associated with the consumption of AFm phase and C-S-H gel. However, as prolonged the CO2 curing time to 7 days, the surface areas with the highest carbonation degree exhibited more chloride content than the inward partially carbonated zone. This is because excessive carbonation at early age could increase the surface pore structures, resulting in the promotion of chloride transport. It was found that the content of chloride and CaCO3 are strongly correlated with CO2 curing time, and CO2 at first 24 h curing can achieve greater benefits in reducing chloride penetration. Moreover, amorphous calcium carbonate gradually transformed into crystalline calcium carbonate during the process of chloride attack, conducive to the further improvement of the compactness of the sample.

Chaos in the Colon: Unlocking the Puzzle of DRA (SLC26A3) Downregulation with IL-1α and p38 MAPK Amidst Brachyspira Turmoil

This study examines the impact of Brachyspira hyodysenteriae and Brachyspira hampsonii infection on chloride (36Cl−) transport within the porcine colon. Utilizing 3H-mannitol and 36Cl−, we evaluated the bidirectional flux across colonic tissues from both healthy and infected pigs. We observed no change in 3H-mannitol flux, indicating unaffected paracellular movement. However, we observed a significant decrease in mucosal-serosal 36Cl− flux (Jm-s) in the apical segment of the spiral colon of infected pigs, suggesting a compromised chloride absorption due to the downregulation of DRA (SLC26A3), confirmed by reduced mRNA and protein levels. To dissect the molecular dynamics in vitro, we exposed polarized Caco-2 cells to B. hampsonii lysate. This model recapitulated the in vivo responses, including the downregulation of DRA and the concomitant IL-1α upregulation. This in vitro model demonstrated that B. hampsonii lysate upregulates IL-1α expression through p38 MAPK phosphorylation. More importantly, in vitro studies with B. hampsonii lysate, recombinant IL-1α, SB 203580 (p38 MAPK inhibitor), and blocking IL-1α signalling with IL-1 receptor antagonist (IL-1RA) revealed that IL-1α has a dose-dependent negative effect on DRA expression and a positive effect on IL-1α expression. Furthermore, inhibiting IL-1α expression with SB 203580 and blocking IL-1α signalling with IL-1RA not only prevented this downregulation of DRA but also promoted its upregulation, highlighting the regulatory role of IL-1α in chloride absorption. In summary, this study presents an in-depth understanding by which Brachyspira infections can impede chloride absorption in the colon and offers potential intervention targets for conditions involving impaired DRA-mediated Cl− transport. This research was supported by Alberta Livestock Meat Association (ALMA 2013R054R) and Natural Sciences and Engineering Research Council of Canada Discovery Grant 02743-2021 (to M. E. Loewen). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Inhibition of neutrophil elastase by the bacterial serine protease inhibitor ecotin in cystic fibrosis airway samples

Abstract Cystic fibrosis (CF), a prevalent fatal genetic condition in North America, disrupts respiratory function by impeding chloride ion transport across mucosal surfaces. This leads to the thickening of mucus, resulting in constant lung inflammation and elevated levels of neutrophils. Neutrophil elastase (NE), a potent serine protease crucial for host defense, is released by these neutrophils. However, in excess, NE can cause detrimental host tissue damage. Abundant in CF airways, NE is a key predictor of lung disease progression. While past studies have explored targeting NE in CF, no optimal inhibitors have reached clinics. Our study tested ecotin, a bacterial periplasmic serine protease inhibitor, for its potential to impede NE activity in CF airway samples and curb NE release from human neutrophils. Results show that ecotin significantly reduces NE activity in sputum samples obtained from several CF patients. Additionally, we found that ecotin inhibits NE release from neutrophils exposed to CF lung stimuli like Staphylococcus aureus bacteria. These results establish ecotin as a promising NE inhibitor in CF with clinical potential.

Research on the mechanism of chlorine corrosion resistance of graphite tailings modified recycled coarse aggregate concrete: Corrosion product transformation and multi-scale mathematical characterization model

This research investigated the impact of substituting sand with graphite tailings (GT) on the chloride ion erosion resistance of recycled aggregate concrete (RAC). The role of GT is to significantly inhibit the penetration of chloride ions into the interior and slow down the corrosion process. However, the durability of graphite tailings recycled aggregate concrete (GTRAC) still depends on the replacement rate of recycled aggregate. At the same time, a multi-scale dynamic model of physical adsorption-chemical binding-free transport and erosion of chloride ions in GTRAC were established based on unsteady viscous fluid force and molecular dynamics.

Durability life evaluation of marine infrastructures built by using carbonated recycled coarse aggregate concrete due to the chloride corrosive environment

Due to the harsh marine environment of chloride ion invasion and corrosion, the issues of long-term chloride transport and durability life evaluation for marine infrastructures constructed/maintained by recycled aggregate concrete (RAC) after enhancement remain poorly understood. For our studies, an accelerated carbonation modification method for recycled coarse aggregate (RCA) was adopted to prepare carbonated recycled coarse aggregate (CRCA) samples, and the macroproperties, i.e., apparent density and water absorption, of CRCA were enhanced by approximately 1.40-3.97% and 16.3-21.8%, respectively, compared with those of RCA. An in-door experiment for chloride transport into concrete specimens subjected to a simulated marine environment of alternating drying-wetting cycles was conducted. The chloride profiles and transport characteristics of carbonated recycled coarse aggregate concrete (CRCAC), recycled coarse aggregate concrete (RCAC), and natural coarse aggregate concrete (NCAC) were analysed and compared. The results indicated that the chloride penetration depths and concentrations of CRCAC were approximately 52.6-96.2% of those of RCAC, which highlighted the better chloride resistance of CRCAC. A chloride transport model for marine concrete structures with various coarse aggregate types in a corrosive marine environment was established. Taking a certain harbour wharf as an example, the durability life of this case considering the application of the CRCAC was evaluated based on the chloride transport model, and the durability life of the CRCAC structure was improved by approximately 28.10% compared with that of the RCAC. The CRCAC developed in this paper has improved mechanical performance and durability than those of RCAC, and it has the potential to replace the NCAC and further support the construction and maintenance of marine infrastructures.

Chloride binding by layered double hydroxides (LDH/AFm phases) and alkali-activated slag pastes: an experimental study by RILEM TC 283-CAM

Chloride binding by the hydrate phases of cementitious materials influences the rate of chloride ingress into these materials and, thus, the time at which chloride reaches the steel reinforcement in concrete structures. Chloride binding isotherms of individual hydrate phases would be required to model chloride ingress but are only scarcely available and partly conflicting. The present study by RILEM TC 283-CAM ‘Chloride transport in alkali-activated materials’ significantly extends the available database and resolves some of the apparent contradictions by determining the chloride binding isotherms of layered double hydroxides (LDH), including AFm phases (monosulfate, strätlingite, hydrotalcite, and meixnerite), and of alkali-activated slags (AAS) produced with four different activators (Na2SiO3, Na2O·1.87SiO2, Na2CO3, and Na2SO4), in NaOH/NaCl solutions at various liquid/solid ratios. Selected solids after chloride binding were analysed by X-ray diffraction, and thermodynamic modelling was applied to simulate the phase changes occurring during chloride binding by the AFm phases. The results of the present study show that the chloride binding isotherms of LDH/AFm phases depend strongly on the liquid/solid ratio during the experiments. This is attributed to kinetic restrictions, which are, however, currently poorly understood. Chloride binding by AAS pastes is only moderately influenced by the employed activator. A steep increase of the chloride binding by AAS occurs at free chloride concentrations above approx. 1.0 M, which is possibly related to chloride binding by the C–(N–)A–S–H gel in the AAS.

Balancing mechanical property and swelling behavior of bacterial cellulose film by in-situ adding chitosan oligosaccharide and covalent crosslinking with γ-PGA

Bacterial cellulose (BC) is an ideal candidate material for drug delivery, but the disbalance between the swelling behavior and mechanical properties limits its application. In this work, covalent crosslinking of γ-polyglutamic acid (γ-PGA) with the chitosan oligosaccharide (COS) embedded in BC was designed to remove the limitation. As a result, the dosage, time, and batch of COS addition significantly affected the mechanical properties and the yield of bacterial cellulose complex film (BCCF). The addition of 2.25 % COS at the incubation time of 0.5, 1.5, and 2 d increased the Young's modulus and the yield by 5.65 and 1.42 times, respectively, but decreased the swelling behavior to 1774 %, 46 % of that of native BC. Covalent γ-PGA transformed the dendritic structure of BCCF into a spider network, decreasing the porosity and increasing the swelling behavior by 3.46 times. The strategy balanced the swelling behavior and mechanical properties through tunning hydrogen bond, electrostatic interaction, and amido bond. The modified BCCF exhibited a desired behavior of benzalkonium chlorides transport, competent for drug delivery. Thereby, the strategy will be a competent candidate to modify BC for such potential applications as wound dressing, artificial skin, scar-inhibiting patch, and so on.

Investigation on chloride releasing from coral aggregates to cement paste in coral aggregate concrete

Coral aggregate concrete (CAC) is one of the most commonly used building materials in construction on marine islands, but the chlorides contained in the coral aggregates (CA) could affect the durability of CAC with steel bars embedded. In this paper, an analytical solution for the diffusion of chlorides from CA into the cement paste in CAC was derivated and the model was established. Studies on chloride releasing behaviours in CAC through an experimental setup of CAC interface specimens with five mixes were conducted. From the analytical model, the chloride diffusion coefficient DCl can be obtained and, different from other reported chloride diffusion coefficient from harden specimen, this coefficient could be the only factor that describes the chloride transport in CAC from the mixing stage. The chloride releasing rate αCl from CA was also calculated and quantified. The results show that the chloride release rate from CA decayed with time and significant chloride release occurred in the first 30 days from the mixture of raw materials, the released amount of chlorides from CA was positively correlated to the average pore size of cement pastes, and the chloride diffusion coefficient of CA in this study was 2–3 magnitudes higher than that of hardened cement paste.

Convection-diffusion-electromigration coupled numerical simulation of water and chloride in cement-based materials

The transport of chloride in cement-based materials is influenced by various factors, and the chloride diffusion coefficient in numerical models should be the steady-state value under specific conditions, which is difficult to obtain through traditional experiments. In this article, based on an improved non-contact resistivity instrument, the steady-state chloride diffusion coefficient and porosity of cement-based materials are characterized. Considering the acceleration effect of moisture convection and electric field on chloride transport, a numerical model for moisture and chloride transport coupling diffusion, convection, and electromigration is established. Based on the measured steady-state chloride diffusion coefficient and porosity values, the influence of interface transition zone (ITZ), electric field type, chloride binding effect, initial conditions, and boundary conditions on moisture and chloride transport is numerically analyzed. It is found that the increase of ITZ thickness, electric field strength, boundary concentration, and initial concentration can accelerate chloride transport. The chloride concentration distribution curve exhibits a “shoulder peak” caused by chloride binding effect, and its peak height and width are positively correlated with the chloride binding coefficient. In conclusion, this study aims to better understand the ion transport behavior inside cement-based materials under coupling of convection, diffusion, and electromigration, and identify the key factors influencing this behavior, which provide a feasible scheme for durable design of concrete construction in environments rich in erosive media.

A Halogen‐Bond‐Driven Artificial Chloride‐Selective Channel Constructed from 5‐Iodoisophthalamide‐based Molecules

AbstractDespite considerable emphasis on advancing artificial ion channels, progress is constrained by the limited availability of small molecules with the necessary attributes of self‐assembly and ion selectivity. In this study, a library of small molecules based on 5‐haloisophthalamide and a non‐halogenated isophthalamide were examined for their ion transport properties across the lipid bilayer membranes, and the finding demonstrates that the di‐hexyl‐substituted 5‐iodoisophthalamide derivative exhibits the highest level of activity. Furthermore, it was established that the highest active compound facilitates the selective chloride transport that occurs via an antiport‐mediated mechanism. The crystal structure of the compound unveils a distinctive self‐assembly of molecules, forming a zig‐zag channel pore that is well‐suited for the permeation of anions. Planar bilayer conductance measurements proved the formation of chloride selective channels. A molecular dynamics simulation study, relying on the self‐assembled component derived from the crystal structure, affirmed the paramount significance of intermolecular hydrogen bonding in the formation of supramolecular barrel‐rosette structures that span the bilayer. Furthermore, it was demonstrated that the transport of chloride across the lipid bilayer membrane is facilitated by the synergistic effects of halogen bonding and hydrogen bonding within the channel.

A Halogen-Bond-Driven Artificial Chloride-Selective Channel Constructed from 5-Iodoisophthalamide-based Molecules.

Despite considerable emphasis on advancing artificial ion channels, progress is constrained by the limited availability of small molecules with the necessary attributes of self-assembly and ion selectivity. In this study, a library of small molecules based on 5-haloisophthalamide and a non-halogenated isophthalamide were examined for their ion transport properties across the lipid bilayer membranes, and the finding demonstrates that the di-hexyl-substituted 5-iodoisophthalamide derivative exhibits the highest level of activity. Furthermore, it was established that the highest active compound facilitates the selective chloride transport that occurs via an antiport-mediated mechanism. The crystal structure of the compound unveils a distinctive self-assembly of molecules, forming a zig-zag channel pore that is well-suited for the permeation of anions. Planar bilayer conductance measurements proved the formation of chloride selective channels. A molecular dynamics simulation study, relying on the self-assembled component derived from the crystal structure, affirmed the paramount significance of intermolecular hydrogen bonding in the formation of supramolecular barrel-rosette structures that span the bilayer. Furthermore, it was demonstrated that the transport of chloride across the lipid bilayer membrane is facilitated by the synergistic effects of halogen bonding and hydrogen bonding within the channel.

Identification of an ultra-rare Alu insertion in the CFTR gene: Pitfalls and challenges in genetic test interpretation

Cystic fibrosis (CF) is a life-limiting genetic disorder characterized by defective chloride ion transport due to mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Early detection through newborn screening programs significantly improves outcomes for individuals with CF by enabling timely intervention. Here, we report the identification of an Alu element insertion within the exon 15 of CFTR gene, initially overlooked in standard next-generation sequencing analyses. However, using traditional molecular techniques, based on polymerase chain reaction and Sanger sequencing, allowed the identification of the Alu element and the reporting of a correct diagnosis. Our analysis, based on bioinformatics tools and molecular techniques, revealed that the Alu element insertion severely affects the gene expression, splicing patterns, and structure of CFTR protein. In conclusion, this study emphasizes the importance of how the integration of human expertise and modern technologies represents a pivotal step forward in genomic medicine, ensuring the delivery of precision healthcare to individuals affected by genetic diseases.

Chloride transport in high-cycle fatigue-damaged concrete

This paper explored the penetration of chloride into concrete damaged by high-cycle compressive fatigue loading. Two environmental conditions including immersion and wetting-drying cycles were prepared for experimentally investigating the transport performance of chloride in fatigue-damaged concrete. Additionally, a prediction model was developed with the damage index of residual strain. Test results revealed that both apparent diffusion coefficients and contents of chloride at each depth increased in fatigue-damaged concrete, indicating that the fatigue damage significantly degraded the resistance of concrete to chloride penetration. Furthermore, for fatigue damaged concretes with extremely different fatigue cycles and load levels but the same residual strain, the chloride ion content profiles were highly overlapped, which demonstrated the reasonability of selecting residual strains as fatigue damage indexes. The applicability of the transport model was firstly validated with the measured chloride contents and then the chloride transport behavior in gradient fatigue-damaged concrete was investigated numerically using the validated model. The numerical results indicated that the chloride transport was more sensitive to the residual strain at the exposed edge than to the residual curvature and the effect of the later can be neglected.

Non-destructive characterization of pore structure and chloride diffusion coefficient of cementitious materials with modified non-contact electrical resistivity method

The intricate pore structure of cement-based materials passively influences chloride ion transport and mechanical properties. Existing non-contact electrical resistivity measurement (NC-ERM) methods lack precision for rigorous studies. the NC-ERM was upgraded in this research, which is suitable for assessing the pore structure and transport characteristics of hardened cementitious substrates. The results obtained from this method closely correspond to those obtained from CEMHYD3D, Mercury intrusion porosimetry (MIP), and other methods. Additionally, the impact of mixture proportions on the resistivity, pore structure parameters, and chloride ion diffusion coefficient of cementitious materials is discussed. With an increase in sand ratio and sand-to-stone ratio, the resistivity exhibits an initial rise followed by a decline. Chloride diffusion of 5 wt% NaCl-saturated specimens is 1.2–1.3 times higher than 3.5 wt% NaCl. This study provides a novel non-destructive, convenient and accurate method for characterising the pore structure and testing the transport properties of cementitious materials.

A Review of Chloride Corrosion Resistance of Ultra-High-Performance Concret

Extending the service life of reinforced concrete structures can effectively reduce the economic, environmental, resource and energy costs throughout their life cycle. However, a large number of reinforced concrete structures often suffer from corrosion of reinforcing bars due to chloride ion erosion in various environments, which leads to deterioration of performance, the loss of functionality and even safety accidents. As a barrier between reinforcing steel and the external environment, protective layer concrete can effectively prevent chloride ions from contacting the surface of reinforcing steel, thus delaying the corrosion of reinforcing steel and improving the durability of reinforced concrete structures. Ultra-high-performance concrete has a dense microstructure due to its low water-to-cement ratio and elimination of coarse aggregates, which can greatly impede the transport of chloride ions within it, and thus it is expected to significantly improve the service life of reinforced concrete infrastructure. Based on this, this paper firstly summarizes the basic mechanism of chloride ion transport inside cementitious materials, including the movement mode and physicochemical binding mechanism of chloride ions inside the cementitious, and analyzes the current research status and improvement methods of the chloride ion penetration and chloride ion binding capacity of ultra-high-performance concrete.