Low Chloride Concentrations Research Articles

Physicochemical characteristics and heavy metals of groundwater during the wet and dry seasons at the Lafarge cement factory environment, Sagamu, Ogun State, Nigeria

AbstractThis study examined the physical, chemical, and heavy metals in groundwater from boreholes and hand‐dug wells at the Lafarge cement factory environment at Sagamu, Ogun State, Nigeria. Water samples were obtained from 20 sampling locations during the wet and dry seasons of 2019. The 17 parameters determined include the pH, temperature, electrical conductivity, total dissolved solids (TDS), total hardness, alkalinity, salinity, chloride, sulfate, phosphate, nitrate, calcium, magnesium, copper, lead, iron, and cadmium. The samples were analyzed using titrimetric and spectrophotometric methods. Correlation analysis was applied as part of the analytical tool in this study. The result indicated low physiochemical concentration of pH, total hardness, sulfate, nitrate, chloride, magnesium, calcium (>1% to 15%), and electrical conductivity (>1000 μS/cm) and fell within the Standard Organization of Nigeria (SON) and World Health Organization (WHO) desirable and maximum permissible limits for potable water during the wet and dry seasons. However, phosphate was above the standard limit for portable water of 6.5 mg/L in all sampling locations, whereas the total alkalinity was above the WHO standard limit (200 mg/L) in 12 locations in the wet seasons and a location in the dry season. Salinity was also above standards in one and four locations in the wet and dry seasons, respectively. Lead and cadmium were not detected in most locations, whereas iron, lead, cadmium, and copper were above standard limits in some locations. A significant relationship exists between the heavy metals and some of the physiochemical parameters at p ≥ .05 and p ≥ .01. The polluted water in most locations is capable of resulting in an adverse health hazard. Thus, this study explains the effect of physicochemical and heavy metals on water management at Sagamu and is important for water resource planning.

Association between urinary chloride excretion and progression of coronary artery calcification in patients with nondialysis chronic kidney disease: results from the KNOW-CKD study.

Urine chloride has recently been suggested as a biomarker of renal tubule function in patients with nondialysis chronic kidney disease (CKD), as low urinary chloride concentration is associated with an increased risk of CKD progression. We investigate the association between urinary chloride excretion and the progression of coronary artery calcification (CAC). A total of 1,065 patients with nondialysis CKD were divided into tertiles by spot urine chloride-to-creatinine ratios. The 1st, 2nd, and 3rd tertiles were defined as low, moderate, and high urinary chloride excretion, respectively. The study outcome was CAC progression, which was defined as an increase in coronary artery calcium score of more than 200 Agatston units during the 4-year follow-up period. Compared to moderate urinary chloride excretion, high urinary chloride excretion was associated with decreased risk of CAC progression (adjusted odds ratio, 0.379; 95% confidence interval, 0.190-0.757), whereas low urinary chloride excretion was not associated with risk of CAC progression. Restricted cubic spine depicted an inverted J-shaped curve, with a significant reduction in the risk of CAC progression in subjects with high spot urine chloride-to-creatinine ratios. High urinary chloride excretion is associated with decreased risk of CAC progression in patients with nondialysis CKD.

Functional interactions between potassium-chloride cotransporter (KCC) and inward rectifier potassium (Kir) channels in the insect central nervous system

The K+/Cl− cotransporter (KCC) is the primary mechanism by which mature neurons maintain low intracellular chloride (Cl−) concentration and has been shown to be functionally coupled to the GABA-gated chloride channels (GGCC) in Drosophila central neurons. Further, pharmacological inhibition of KCC has been shown to lead to acute toxicity of mosquitoes that highlights the toxicological relevance of insect KCC. Yet, gaps in knowledge remain regarding physiological drivers of KCC function and interactions of ion flux mechanisms upstream of GGCC in insects. Considering this, we employed electrophysiological and fluorescent microscopy techniques to further characterize KCC in the insect nervous system. Fluorescent microscopy indicated insect KCC2 is expressed in rdl neurons, which is the neuron type responsible for GABA-mediated neurotransmission, and are coexpressed with inward rectifier potassium (Kir) 2 channels. Coexpression of Kir2 and KCC2 suggested the possibility of functional coupling between these two K+ flux pathways. Indeed, extracellular recordings of Drosophila CNS showed pre-block of Kir channels prior to block of KCC led to a significant (P < 0.001) increase in CNS firing rates over baseline that when taken together, supports functional coupling of Kir to KCC function. Additionally, we documented a synergistic increase to toxicity of VU0463271, an established KCC inhibitor, above the expected additive toxicity after co-treatment with the Kir inhibitor, VU041. These data expand current knowledge regarding the physiological roles of KCC and Kir channels in the insect nervous system by defining additional pathways that facilitate inhibitory neurotransmission through GGCC.

Combination of sequencing batch reactor and vertical flow treatment wetlands: A full-scale experience for rum distillery wastewater treatment in a tropical climate

Distillery wastewater is a difficult type of wastewater to treat because of its low pH (pH = 3.3), high chloride and sulfate content, high organic matter concentrations (3.2 gTSS/L, 6.8 gBOD5/L and 14.6 gCOD/L). Moreover, the rum production is intermittent over the season (5 months per year). The acidity of this type of wastewater, combined with the relatively underbalanced nitrogen concentrations, requires the addition of specific chemicals such as soda solution and urea, when a biological treatment technology is envisioned. In this full scale experiment, located in a tropical zone (Martinique island), the objective was to demonstrate the ability of treatment chain composed of a sequencing batch reactor (SBR) followed by vertical flow treatment wetlands (VFTWs). The objective was to use VFTWs for treatment polishing as well as sludge/water separation and sludge treatment over years. The VFTWs are planted with Heliconia psittacorum and Cyperus papyrus. The monitoring occurred during three rum production seasons. The treatment chain allows an overall average removal of TSS of 92% and 96% for organic matter (COD and BOD5). The average annual load applied to the filter in operation was 32 kgTSS/m²/y, which is equivalent to 78 kgTSS/m²/y over the distillation period. The applied load was too high for the plants tested and lead to plant death and surface clogging of the filters. Nevertheless, this experiment allowed specifying the way to operate the whole treatment plant as well as acceptable daily loads that should be applied on the VFTWs. Even if the operation of the filters and the selection of plants in a tropical climate still need to be optimized, this combination of intensive and extensive processes is an effective and sustainable nature-based solution for rum distillery wastewater treatment.

Corrosion of Synthetic Intermetallic Compounds and AA7075-T6 in Dilute Harrison’s Solution and Inhibition by Cerium(III) Salts

This study addresses the behavior of an aluminum alloy and its components in conditions simulating the presence of atmospheric salts. The corrosion of synthetic intermetallic compounds (IMCs) Al2Cu, Al2CuMg, Al7Cu2Fe, MgZn2, and bulk aluminum alloy 7075-T6 was studied in dilute Harrison’s solution (DHS, 0.35 wt% (NH4)2SO4 + 0.05 wt% NaCl). For IMCs, electrochemical measurements were performed using a microcell, and a standard electrochemical cell was used to study the bulk alloy. Separately measured cathodic and anodic potentiodynamic polarization curves were recorded, and prolonged immersion was characterized using electrochemical impedance spectroscopy. Samples were characterized using scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. Bulk AA7075-T6 was less susceptible to corrosion in DHS than in chloride solution stemming from the beneficial presence of sulfate ions and lower chloride concentration. The susceptibility of IMCs to corrosion in DHS increased in the order Al2Cu < Al7Cu2Fe < Al2CuMg < MgZn2 due to the increased dissolution of Mg in the presence of ammonium ions. The relative nobility of IMCs was determined based on the galvanic current density. Further, the possibility of using cerium chloride, nitrate and acetate salts as corrosion inhibitors in DHS was evaluated. Ce salts acted as inhibitors for the alloy during 14 d testing, forming a Ce hydroxide layer. The degree of protection depended on the type of anion, with acetate Ce salt giving the most efficient protection. For the IMC, however, inhibition by Ce salts did not occur during short measurements in the microcell, indicating the importance of galvanic interaction with the alloy matrix in the inhibition mechanism, which was confirmed by long-term measurements of the alloy.

Chemical vectoring in continental geothermal systems: Composition of altered rocks and illite as guides to magmatic degassing

The Taupō Volcanic Zone, New Zealand, is one of the most voluminous volcanic regions on Earth. Over the last 1.8 Myr, bimodal volcanism in this rifted-arc setting has been dominated by voluminous rhyolite ignimbrite eruptions (>6000 km3 cumulative) and minor arc-type andesite and dacite, underpinned by basaltic intrusions. The combination of the magmatism and extensionally thinned arc crust with high heat flow has resulted in more than 23 active geothermal fields in the region. The fluids sampled in the geothermal systems are dominated by dilute meteoric fluids that are low in components such as acids, alkalis, and some trace metals commonly ascribed to magmatic sources but can contain large amounts of deep sourced magmatic volatiles such as CO2.This study was designed to assess the long-term (>20,000yr) fluid and metal input into two Taupō geothermal systems, and the amount and proportion of magmatic-derived components in these fluids. We collected major and trace element compositions of hydrothermal altered whole rocks and clay minerals from two active geothermal systems and compared them with hydrothermally altered rocks of the fossil (0.6 Ma) Ngatamariki magmatic-hydrothermal system, which has a demonstrated large magmatic contribution. The Ohaaki and Rotokawa geothermal systems have both been drilled to a depth of 3000 m, with sampled reservoir fluids containing low concentrations of chloride (∼1000 mg/kg) but high levels of gas (CO2, N2) that have previously been interpreted to reflect subduction components derived from arc-type magmas. Whole-rock samples lack enrichment in chloride-transported metals such as Cu, Pb or Zn but have minor anomalies of bisulfide-complexed Au, Sb, and As in the uppermost 1500 m of the geothermal reservoirs. Hydrothermal water-rock interactions in the deep reservoirs of both geothermal systems at temperatures between 220 and 300 °C produced assemblages of illite + albite + adularia + calcite + pyrite that are in equilibrium with the observed neutral to slightly acidic pH (6 ± 1) of the present-day fluids. In the lower temperature end of this range, Mg and Fe increasingly enter the illite crystal lattice via Tschermak-type (phengite) substitution, whereas a few high-temperature (>300 °C) samples contain scarce muscovite compositions. The illites commonly have low contents of most trace metals, although minor amounts of Cs, Li, Cu, Sb and Sn occur in near-surface samples. Based on these data, over the >20,000-year lifetime of the Ohaaki and Rotokawa geothermal systems, fluids were dominated by chloride-poor meteoric water and contained little magmatic contributions other than conducted heat, some gases (CO2 - N2 ± H2S), and a small fraction of the total H2O of geothermal waters. Therefore, the inferred magma bodies of intermediate to silicic composition that lie at shallow depth beneath these geothermal systems currently are not, and likely have not been for >20,000 years, degassing significant water and chloride despite the high water and chloride contents of the magmas. By inference, the intermediate to silicic magmas at depth have not transferred large amounts of volatiles to the geothermal systems over this period, and rather are storing them in the magmatic bodies to be released in volcanic eruptions that are commonly explosive and pyroclastic in nature and highly hazardous.

Add a dash of salt? Effects of road de-icing salt (NaCl) on benthic respiration and nutrient fluxes in freshwater sediments

Winter road salt applications are increasing chloride concentrations in many freshwater ecosystems. This trend is alarming, giv¬en chloride’s potential to impair aquatic ecosystems. Short- and long-term exposure to salt could affect ecosystem metabolism and nutrient cycles. Here, we examine connections between chloride concentrations, water quality conditions, benthic respi¬ration, and sediment-water nutrient flux throughout a large (722 km2) lake and its catchment. Aquatic locations experiencing high concentrations of chloride are indicators of anthropogenic activities and are often associated with additional pollutants. We used sediment core flow-through incubations under ambient and enriched chloride concentrations to determine the effects of road salt on benthic respiration and nutrient fluxes in stream, stormwater pond, and lake sites. Salt (as sodium chloride) ad¬ditions caused a significant overall increase in benthic respiration. Acute exposure to road salt caused the strongest increase in benthic respiration when water was warm and at sites that had low (&lt; 50 mg Cl-/L) or high (&gt; 400 mg Cl-/L) ambient chloride concentrations or when water was cold and sites had intermediate (100-400 mg Cl-/L) ambient chloride concentrations. Nitrate flux responded less uniformly to salt additions. Depending on waterbody type and season, ambient nitrate flux into the sediment was similar, increased, or decreased post-chloride addition. Dissolved phosphorus flux was not significantly impacted by salt additions. Across lake and stream sites, our results supported the hypothesis that chloride causes increased respiration while nutrient cycles were weakly and inconsistently altered under experimental pulse road salt additions.

Calibrating a model to 30 years of data to capture the accumulation of chloride from winter deicers in a shallow aquifer

AbstractWinter deicers are a major source of chloride contamination to shallow aquifers in northern latitudes. In the greater Chicago area of northeast Illinois, chloride has been accumulating for decades and in many places now exceeds the United States Environmental Protection Agency secondary standard of 250 mg/L. MODFLOW‐NWT and MT3D‐USGS were used to simulate the accumulation of chloride with 30 years of data in the shallow aquifer of Will County in northeast Illinois. This aquifer is composed of unconsolidated sediments, largely from glacial deposits, overlying a fractured dolomite bedrock. To calibrate to observed heads and chloride, the model needed refined geologic features, higher chloride concentrations on cells representing commercial or industrial lands, lower chloride concentrations on cells representing roads, and point source areas to speed chloride's emergence in the aquifer. These point sources are locally significant and could represent different anthropogenic or geologic features, such as municipal stormwater infrastructure. Future simulations indicate that chloride is not at steady state in the shallow aquifer and wells are at risk of exceeding the secondary standard if winter deicing applications are not reduced. It may take decades for the full impacts of reduced deicing rates to be observed in wells, owing to the long residence time of water in the aquifer. This transient model calibration was possible because of the 30‐year dataset collected by communities and government agencies.

Effect of monovalent electrolyte solutions on the human tear ferning pattern.

To investigate the effect of the addition of a low concentration of sodium chloride (NaCl) and potassium chloride (KCl) solutions on the tear ferning (TF) patterns of tears collected from humans. A tear sample (20 μL) was collected from the right eye of 23 males and 7 females (25.4 ± 6.6 years). The tears were collected in one sitting for healthy subjects (N = 13). For dry eye participants (N = 17), the tear samples were collected in two separate settings with five minutes gap in between. A sample (1 μL) from each tear was dried on a glass slide, and the obtained ferns were observed using a microscope and graded using the five-point TF grading scale. Mixtures of tear samples (0.5 μL) and different volumes (0.5-2.5 μL) of each electrolyte (10-30 mg in 100 mL of water) solution were prepared, and their TF patterns were recorded and compared with those of the corresponding pure tears. Significant improvements (Wilcoxon test, P < 0.001) have been seen in the TF grades of the tear samples after the addition of NaCl and KCl solutions. A significant difference (Wilcoxon test, P = 0.016) was found between the TF grades when NaCl and KCl solutions were added to the tear samples. The TF grades of pure tears collected from dry-eye subjects ranged from 2.1 to 3.5, based on the five points grading scale, and decreased to be in the range of 0.4 to 1.6 after the addition of electrolyte solutions. While the TF grades of pure tears collected from normal-eye ranged from 1.2 to 1.9 and improved after the addition of electrolyte solution to be in the range of 0.4 to 1.5. The TF test was used in vitro to assess the impact of the addition of a low concentration of sodium and potassium chloride solutions on tears collected from humans. The TF grades of human tears significantly improved after the addition of either sodium or potassium chloride solution. The mechanism for the improvement in TF grades due to the addition of electrolyte solutions must be investigated.

Effect of Cisplatin and Its Cationic Analogues in the Phase Behavior and Permeability of Model Lipid Bilayers

Increasing evidence suggests a critical role of lipids in both the mechanisms of toxicity and resistance of cells to platinum(II) complexes. In particular, cisplatin and other analogues were reported to interact with lipids and transiently promote lipid phase changes both in the bulk membranes and in specific membrane domains. However, these processes are complex and not fully understood. In this work, cisplatin and its cationic species formed at pH 7.4 in low chloride concentrations were tested for their ability to induce phase changes in model membranes with different lipid compositions. Fluorescent probes that partition to different lipid phases were used to report on the fluidity of the membrane, and a leakage assay was performed to evaluate the effect of cisplatin in the permeability of these vesicles. The results showed that platinum(II) complex effects on membrane fluidity depend on membrane lipid composition and properties, promoting a stronger decrease in the fluidity of membranes containing gel phase. Moreover, at high concentration, these complexes were prone to alter the permeability of lipid membranes without inducing their collapse or aggregation.

Effect of renal function on the prognostic importance of chloride in patients with heart failure.

Hypochloremia has recently gained interest as a potential marker of outcomes in patients with heart failure (HF). The exact pathophysiologic mechanism linking hypochloremia to HF is unclear but is thought to be mediated by chloride-sensitive proteins and channels located in kidneys. This analysis aimed to understand whether renal dysfunction (RD) affects the association of hypochloremia with mortality in patients with HF. Using data from a nationwide registry, 438 cases with complete data on serum chloride concentration and 1-year survival were included in the analysis. Patients with an estimated glomerular filtration rate of <60 mL/min/m2 at baseline were accepted as having RD. Hypochloremia was defined as a chloride concentration <96 mEq/L at baseline. For HF patients without RD at baseline, patients with hypochloremia had a significantly higher 1-year all-cause mortality than those without hypochloremia (41.6% vs 13.0%, log-rank p < 0.001) and the association remained significant after multivariate adjustment (odds ratio (OR): 2.55, 95% confidence interval (CI): 1.25-5.21). The evidence supporting the association was very strong in this subgroup (Bayesian Factor (BF)10: 48.25, log OR: 1.56, 95% CI: 0.69-2.43). For patients with RD at baseline, there was no statistically significant difference for 1-year mortality for patients with or without hypochloremia (36.3% vs 29.7, log-rank p = 0.35) and there was no evidence to support an association between hypochloremia and mortality (BF10: 1.18, log OR :0.66, 95% CI: -0.02 to 1.35). In patients with HF, the association between low chloride concentration and mortality is limited to those without RD at baseline.

Removal of cadmium from phosphoric acid in the presence of chloride ions using commercially available anion exchange resins

The production of cadmium-free phosphoric acid is crucial for the manufacturing of environmentally friendly fertilizers. One of the most promising methods for purification of phosphoric acid is ion exchange/adsorption. The article presents studies on the adsorption of cadmium from a 40 % phosphoric acid solution in the presence of chloride ions with the use of commercially available anion exchange resins. Five borderline cases were examined in a batch system, as well as kinetic studies were performed. The effect of chloride (0.2–2.2 wt%) and cadmium (5–2500 mg/kg) concentration on adsorption with the use of two best resins was studied in depth. The Amberlite PWA5 resin was selected for column tests and for experiments with wet process phosphoric acid simulated solution (WPPA-SS) to prove the concept of practical application of the resin. The obtained results indicate that PWA5 has a number of advantages over the resins tested so far, e.g., the resin is characterized by high cadmium adsorption efficiency (89 % in batch experiments with WPPA-SS and 95.5 % in column tests), the resin effectively adsorbs cadmium in the presence of low chloride concentrations (0.2–0.5 wt%), and the column with this resin can work properly even at high flow rates (40 BV/h).

Encapsulation of Brunfelsia pauciflora microprogated shoots as a suitable conservation protocol

The percent work aimed to establish an efficient in vitro propagation and conservation protocol for Brunfelsia pauciflora plant using encapsulation techniques that allow the genetic stability of conserved material. The effect of plant growth regulators types (BAP, Kin, 2ip, and NAA) and concentrations at 0.0, 1.0, and 2.0 mg/l were stud-ied during the establishment phase in comparison with a hormonal-free medium. In vitro proliferated shootlets were encapsulated using various levels of sodium alginate at 1, 2, and 3% (W/V) and calcium chloride at 2.5,5 and 10 %. The regrowth ability of encapsulated explants was evaluated after conservation for 3, 5, and 7 weeks and compared with non-encapsulated buds. The findings of the current study proved that during the establish-ment phase, applying BAP at 2.0 mg/l gave the best results during the three successive subcultures. The best treatment 2ip (2.0mg/l) + BAP (2.0mg/l) + NAA (2.0mg/l) that was considered ideal propagation protocol for shooting and rooting of Brunfelsia. Successful plant recovery from encapsulated explants using low concentra-tions of sodium alginate (1%) and calcium chloride at 2.5% proved that the explants could to survive at the high-est percent (100%) during conservation periods 3, 5, and 7weeks. Increasing calcium chloride to 5% with the same concentration of sodium alginate (1%) caused a gradually reduced percent of survival to 53.33% with an increasing conservations period (from 3 to 7weeks). It is the first paper on the application of the syndetic seed technique on Brunfelsia for the shortest period of conservation and successive renovation of shootlets whose genetic stabilization was evaluated by analysis of RAPD that proved that the genetic similarity ranged from 56.1 to 80%. These results were confirmed by anatomical sections made in Brunfelsia leaf blade.

On the effect of simulated contamination of chlorides and sulfates on steel rebar corrosion: Electrochemical behavior and surface analysis

To understand the effect of sulfate ions on the chloride-induced corrosion of reinforced concrete, this study focuses on the electrochemical behavior and surface analysis of standarded carbon steel that was exposed to simulated pore solutions, with different combinations of high and low chloride and sulfate concentrations. Linear scanning voltammetry and electrochemical impedance spectroscopy were used to monitor the corrosion reaction. Steel surface was characterized by X-ray photoelectron spectroscopy and field emission scanning electron microscopy. Results indicate that the presence of sulfate affects the electrochemical behavior of steel corrosion at a low and high chloride concentration, where the capability of the corrosion protective layer was influenced by the increase of the sulfate and chloride content. Calcium carbonate deposits were observed at the surface of corroded samples, where higher precipitation of calcium carbonate crystals on carbon steel surface is associated with higher rates of localized corrosion.

(Digital Presentation) Fundamentals of Deep Eutectic Solvents As Electrolytes for Lithium-Ion Batteries

Deep eutectic solvents (DESs) have emerged as an alternative to both common organic solvents and ionic liquids (ILs). DESs share physicochemical properties with ILs such as low vapor pressure, high thermal stability, high viscosity while offering advantages such as low toxicity, lower cost, and ease of preparation. Moreover, DESs are attractive candidates for electrochemical applications due to their large voltage windows and solubility properties. DESs as a solvent class share a general composition of a hydrogen bond donor (HBD), typically a polyol, amide, or acid, and a hydrogen box acceptor (HBA), usually a quaternary ammonium or phosphonium salt. At a specific molar composition of a HBD and HBD, the DES forms a eutectic mixture resulting in a large melting point depression due to extensive hydrogen bonding between the components.Despite being widely studied, the microscopic structures of DESs have remained largely uncharacterized. Herein, we present a multitechnique NMR study of two DESs: glyceline (glycerol + choline chloride) and ethaline (ethylene glycol + choline chloride). Fast-field cycling 1H relaxometry, pulsed field gradient diffusion, nuclear Overhauser effect spectroscopy (NOESY), 13C NMR relaxation, and pressure-dependent NMR experiments are deployed to sample a range of frequencies and modes of motion of the polyol and choline components of the DES. Generally, translational and rotational diffusion of polyols are more rapid than those of choline while short-range rotational motions observed from 13C relaxation indicate slow local motion of glycerol at low choline chloride (ChCl) content. We show how the additional hydroxyl group present in glycerol contributes to not only higher viscosities, but a larger perturbation of the hydrogen bonding network by the addition of ChCl.Additionally, we have investigated the solubility properties of several lithium salts (LiTFSI, LiFSI, LiPF6, LiBF4, and LiOAc) in these DESs and utilized the same suite of NMR techniques to understand how they act as solvents. We observe that due to anion effects, the heterogeneities present in DES result in differential solvation for some species where there is a distinction of lithium salts co-existing in these holes as well as the bulk. The large changes in the structural organization of DESs that result from the presence of lithium salts will serve as a guide to the design of a new class of electrolytes for lithium-ion batteries.

Electrochemical Assessment of Galvanized Steel Corrosion in Alkaline Sulfate Solution

Corrosion of steel prestressing strand in bonded post-tensioned bridge tendons have been associated with elevated concentrations of sulfate ions in deficient grout that can develop due to grout segregation [1]. Previous research indicated that the early presence of elevated sulfate ion concentration in the deficient grout in contact with the embedded steel can impair steel passivity. Metastable pitting was observed for steel in saturated calcium hydroxide solutions with sulfate ion concentrations greater than 1,300 ppm and pitting was observed in solutions above 20,000 ppm [2-4]. In addition to steel strand corrosion, galvanized steel ducts in direct contact with the deficient grout with elevated sulfate ion concentrations were also observed to have severe localized corrosion [1]. Galvanized steel in alkaline solutions, such as in cement pore water, have been characterized to have greater resistance to chloride-induced corrosion with chloride threshold concentrations as much as 2.5 times greater than carbon steel [5]. Information relating to sulfate concentrations is less available. Electrochemical testing including the electrochemical noise (EN) technique was conducted to identify the role of early sulfate ion presence on corrosion of galvanized steel.EN provides a test method to assess the corrosion modality without the influence of an external excitation that can affect the electrode surface and electrolyte chemistry (such as metal oxidation and oxygen reduction) [6-7]. The testing aims to identify the corrosion mitigation characteristics of the galvanized steel such as zinc activity and protective barrier surface oxide layers in presence of sulfate ions as well as combined cases with chloride ion contamination below reported threshold concentrations for galvanized steel. In the testing here, steel specimen were exposed to alkaline solutions simulating pore solutions with pH 12.6 with varying sodium sulfate levels and sodium chloride. Supplemental electrochemical experiments included the steady-state condition (open circuit potential, linear polarization test, and electrochemical impedance spectroscopy). References K. Lau, and I. Lasa. "Corrosion of prestress and post-tension reinforced-concrete bridges." Corrosion of steel in concrete structures. Woodhead Publishing, 2016. 37-57. DOI: https://doi.org/10.1016/B978-1-78242-381-2.00003-1.S. Permeh, K. K . Krishna Vigneshwaran, K.Lau., and I.Lasa. “Corrosion of Post-Tensioned Tendons with Deficient Grout. Part 3: Segregated Grout with Elevated Sulfate and Vestigial Chloride Content.” Corrosion 75 (2019) pp.848-864.S. Permeh, K. Lau, M. Duncan, and R. Simmons. “Initiation of localized steel corrosion in alkaline sulfate solution.” Materials and Structures, 54 (2021), pp.1-17.S. Permeh, K. Lau, M. Duncan, and R. Simmons. “Identification of steel corrosion in alkaline sulfate solution by electrochemical noise.” Materials and Corrosion, 72(2021), pp.1456-1467.S. Yeomans. Galvanized steel reinforcement in concrete. Elsevier, 2004.S. Permeh, and K. Lau. "Electrochemical Behavior of Steel in Alkaline Sulfate Solutions with Low Level Chloride Concentrations." ECS Meeting s. No. 10. IOP Publishing, 2021.K. Lau, S. Permeh. “Assessment of durability and zinc activity of zinc-rich primer coatings by electrochemical noise technique.” Progress in Organic Coatings, 167(2022): 106840.

Hydrogen Crossover Flux through Two-Dimensional Nanomaterials

Energy Storage and conversion devices require an ion-exchange membrane to accomplish high transmission of charge-balancing ions and separation of anode and cathode electrolytes/gases from mixing. These critical functions of membranes play a pivotal role in ensuring device optimum performance and higher efficiency. Most conventional membranes suffer huge ionic and molecular species cross-permeation resulting in low energy efficiency and material degradation. In this work, hydrogen permeability and proton transmission through membrane electrode assemblies (MEAs) that contain a monolayer of hexagonal boron nitride, single-layer and bi-layer graphene were investigated in a gas-phase small-scale cell and a liquid cell. We found that the hydrogen crossover flux through MEAs with 2D materials was inhibited by at least a factor of 5 as compared to the one without. Single-layer graphene and boron nitride enabled high proton transmission, but bi-layer graphene inhibited proton conduction. Defect visualization of 2D materials by chemical treatment with a low ferric chloride concentration followed by imaging using a digital microscope revealed few atomic-scale defects in graphene. These findings suggest that a monolayer of 2D material may provide good selectivity for energy conversion and storage devices by blocking species crossover while allowing high proton transmission.

Relation of Low Chloride Concentration to Diuretic Efficiency and Transplant-Free Survival in Children Hospitalized With Heart Failure

Serum chloride plays an important role in fluid homeostasis and is associated with impaired diuretic responsiveness and mortality in adults with heart failure (HF). We sought to characterize the relationship of serum chloride and diuretic efficiency (DE) and to determine its prognostic importance in children hospitalized with acute decompensated HF (ADHF). We studied DE, defined as net fluid output/kg+constant per mg of loop diuretic/kg, in 200 children hospitalized with ADHF. Median serum chloride at admission was 102 mmol/L (interquartile range 99 to 105 mmol/L), and hypochloremia (chloride ≤96 mmol/L) was present in 16% of the population at admission. Serum chloride correlated with serum sodium (r=0.66; p < 0.001) and bicarbonate (r=-0.39; p < 0.001). In the adjusted analysis, lower chloride was associated with reduced DE (p < 0.001). Serum sodium was associated with DE on the unadjusted analysis; however, the association was eliminated when added to the model with chloride (p=0.442). Lower chloride was also associated with features of inadequate decongestion during hospitalization: a positive fluid balance (p=0.003), greater cumulative loop diuretic dose per weight (p=0.001), addition of a thiazide diuretic during hospitalization (p < 0.001), less weight loss (p=0.025), and longer length of stay (p=0.003). Chloride concentration was independently associated with death or transplant 1 year after admission (hazard ratio 0.94; p < 0.001). As a dichotomous variable, hypochloremia was independently associated with reduced DE (p < 0.001) and decreased 1-year transplant-free survival (hazard ratio 2.3, p < 0.001). Lower serum chloride at hospital admission is strongly and independently associated with impaired DE and reduced transplant-free survival in children hospitalized with ADHF.

The Investigation of the Impact of Toxicity of Metals on Oxygen-Evolving Complex in Spinacia oleracea.

The current article reported the investigation of metal toxicity on the oxygen-evolving complex (OEC) in Spinacia oleracea related to depletion in chloride ion concentration, an essential part of the photosystem (II). The greenhouse experiment was conducted where S. oleracea was cultivated in three replicates with control plants (plants “a”) treated with tap water. Moreover, 30 ppm of Cu2+ ion solution and Pb2+ ion solution was used to irrigate the rest of the plants, labeled as plants “b” and “c”, respectively, on alternative days. Advanced technologies such as Atomic Absorption Spectrophotometry (AAS), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and UV-visible Spectrophotometry were used to monitor the essential nutrients in leaves to validate the function of the photosystem (I and II). Reduced Cl− ions contents showed that both metals (Cu2+ and Pb2+) altered the essential elements of the oxygen-evolving complex (OEC) of photosystem (II), required to maintain the coordination structure of the Mn4CaO5 cluster. SEM analysis revealed the modified leaf structure of the S. oleracea under Cu2+ and Pb2+ accumulation due to which distorted cellular structure, reduced surface area, and the (shattered) stomatal opening compared to the plants “a” were observed. The EDS analysis of plants “b” and “c” showed high oxygen contents followed by reduced chloride contents over plants “a”, reflecting the infirmity of OEC to push out oxygen, which leads to generating oxidative stress. The lower pigment concentration in leaves of metal-contaminated plants “b” and “c” impacts carbon assimilation, which is linked to the reduced stomatal opening and influences the gaseous exchange rates. Additionally, increased contents of K+ and Ca2+ may be due to self-defense mechanisms under low chloride contents to speed up oxygen evolution to protect plants against oxidative stress. It was concluded that Cu2+ and Pb2+ metal toxicity influences essential Cl− and K+ contents, which modify the photosystem II system; subsequently, a reduced growth rate was observed.

Effects of Low Concentrations of NaCl and EG on Hydrate Formation Kinetics and Morphology in the Presence of SDS

The research on gas hydrates can be divided into two subfields: risk prevention and control of pipeline blockage by hydrates and industrial applications of solidified natural gas (SNG) in gas storage and transportation, seawater desalination, and gas recovery. The two opposing properties of hydrates have stimulated research into promoting and inhibiting methods. A considerable number of studies have reported that the same type of additive can play a promoting or inhibiting effect at different concentrations. This study evaluated the kinetic effects of low concentrations of ethylene glycol (EG) and sodium chloride (NaCl) on methane hydrate production in sodium dodecyl sulfate (SDS) solution. The results showed that both NaCl and EG had kinetic inhibitory effects on the hydrate reaction in SDS solution, and the inhibitory effects gradually increased with the increase of the concentration. Among them, the inhibitory effect of NaCl was stronger than that of EG at the same content. 5 wt % NaCl can reduce the reaction rate of hydrate in SDS solution by 81%, but 0.1 wt % NaCl helped SDS to act on hydrate growth, and the rate of hydrate growth stage was increased by 100%. When 0.1 wt % NaCl or 5 wt % EG existed in the SDS solution, the hydrate mainly grew in the bulk solution and on the inner wall surface of the container, forming a peak-like structure below the interface, and 5 wt % EG also formed a ridge-like structure above the interface. Exploring the macroscopic formation characteristics of hydrate is helpful to industrial process optimization and predicting the additive concentration in the pipeline. This work emphasizes that the selection of substances can be broadened and the rational use of resources can be achieved as much as possible when selecting promoters that are conducive to hydrate formation kinetics or inhibitors that control hydrate growth.