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The consumption of the Pt electrocatalyst, which occurs when aqueous solution with neutral pH is electrolyzed with a Pt electrode to produce hydrogen or oxygen, was measured from the change in resonance frequency using the QCM method. First, it was found that the Pt consumption from the electrode during water electrolysis while applying a steady positive potential was very small, but it was almost proportional to the time the current was applied. Second, when electrolysis was performed by polarity reversal electrolysis of the anode and cathode periodically during electrolysis, the amount of Pt consumed increased in proportion to the number of polarity reversal was exchanged. The Pt consumption obtained by the QCM method was in close agreement with the value obtained by EDX method, proving the validity of the measurement method. The QCM measurement method was also proven to be a reliable method of measurement. • Constant-current water electrolysis, Pt anode consumed slightly with time. • Polarity reversals water electrolysis, Pt consumed increases with number of times. • Chloride ion concentration affects Pt electrode consumption in a nonlinear manner. [ABSTRACT FROM AUTHOR]

Based on the passivation of iron in alkaline solutions, aqueous alkaline treatment has been taken as an effective desalination technique to increase the stability of archaeological iron. However, chlorides may destroy the passivation of iron artifacts, causing damage to the treated artifacts during desalination. In this study, electrochemical and microstructure analyses were carried out in alkaline solutions with known chloride content, using archaeological iron and pre-corroded iron coupons with varying chloride levels within the rust layer. The study revealed that alkalinity ensures passivation even in the presence of chloride within the rust layer. However, the passivation weakens as the concentration of ‘free’ chloride ions in the alkaline solution increases due to their migration from the rust layer, leading to active corrosion. A chloride threshold value (CTV) of 355 ppm in 0.1 mol/L NaOH solution was established as a chloride level for the replacement of the alkaline solution. The determination of CTV based on electrochemical measurements is intended to guide the timely replacement of the desalination solutions, thereby preventing chloride-induced iron corrosion during desalination treatments. [ABSTRACT FROM AUTHOR]

• A novel detection method for PS is developed based on the redox between PS and Cl−. • The method can avoid the interference of H 2 O 2 and most oxidizing species. • The method can determine the PS concentration in wastewater or content in products. • The detection range of the method is 1 to 100 g/L with error range of 0.53−12.06%. Persulfate (PS) is a widely used oxidant for the chemical oxidation of organic pollutants. The accurate measurement of PS concentration is crucial for the practical application process. The iodometry is the most recommended method for PS determination, and its principle is based on the redox reaction between S 2 O 8 2− and iodide ions. However, hydrogen peroxide (H 2 O 2), an important intermediate product in the process of PS use, often leads to abnormally high determination concentrations of PS. Given this, a novel method was developed for the determination of PS based on the principle of the oxidation of chloride ion (Cl−). The concentration of PS is calculated according to the consumption of Cl− concentration, which is not disturbed by H 2 O 2. The optimized test conditions were explored as: C(H+) = 2 mol/L, T = 80℃, C(Cl−):C(PS) = 4:1 and t = 30 min. Under the optimized conditions, the limit of detection and the limit of quantification of PS concentration determined by this method were 0.26 and 0.85 g/L, respectively. And the linear range of the PS determination was 1–100 g/L with an error of 0.53%-12.06%. The spike recovery rate for determining PS concentration in the actual wastewater ranged from 94.07%-109.52%. Interfering factors such as H 2 O 2 , Fe3+, MnO 2 and natural organic matter had almost no effect on the results. This method could not only accurately determine the concentration of PS in industrial wastewater, but also determine the purity of PS industrial products. [ABSTRACT FROM AUTHOR]

Seawater with different salt concentration and different infiltration frequency were simulated to carry out seawatererosion test on standard formed concrete specimens and determine chloride ion content. The determination of internal freechloride ion content, fitting of surface chloride ion content curve, and study on the surface chloride ion concentration time rulewere conducted under different salinity. The content of free chloride ions at different depths under different infiltrationfrequency was determined, and the relationship between surface chloride ion concentration and different infiltration frequencywas analyzed and studied. The results show that the content of free chloride in concrete increases with the increase of salinityand erosion time. The temporal evolution of chloride ion concentration on concrete surface meets the power index model, andthe power index parameter varies with the change of infiltration frequency. Within a certain age, the law of the influence ofsalinity on the chloride ion concentration on the concrete surface meets the logarithmic function model. When the infiltrationfrequency is low, the chloride ion penetration of concrete increases with the increase of the frequency. When the infiltrationfrequency is increased to 12 times/d the infiltration rate of chloride ions slows down and the content of free chloride ions inconcrete decreases. [ABSTRACT FROM AUTHOR]

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The chloride content is a critical factor influencing the corrosion of steel fibers in concrete. This study focused on the corrosion behaviors of steel fibers exposed to simulated concrete pore solutions with different chloride contents. The corrosion rates of the steel fibers were calculated based on the changes in the diameter and ultimate tensile load. The electrochemical parameters for the corrosion of the steel fibers were continuously monitored for 62 days. In addition, the surface micromorphologies of the corroded steel fibers were observed using scanning electron microscopy (SEM). The results showed that based on the change in the diameter, the corrosion rate of the steel fibers increased almost linearly when the NaCl content in the simulated solution increased from 2% to 5%. However, based on the variation of the ultimate tensile load, the corrosion ratio of the steel fibers increased linearly with the increase in the exposure time when the NaCl content was less than 3%, while it increased exponentially when the NaCl content exceeded 3%. According to the open circuit potential, Tafel polarization curves, and electrochemical impedance spectroscopy (EIS), the corrosion tendency and corrosion rates of the steel fibers exposed to the simulated solutions increased significantly when the NaCl content increased from 2% to 5%. Additionally, the corrosion damage on the surfaces of the steel fibers increased notably, and after 180 days of exposure to the simulated solution with 5% NaCl, the steel fiber was almost broken. These findings will help to understand the durability of SFRC in a chloride environment. [ABSTRACT FROM AUTHOR]

Osmotic stress and chloride regulate the autophosphorylation and activity of the WNK1 and WNK3 kinase domains. The kinase domain of unphosphorylated WNK1 (uWNK1) is an asymmetric dimer possessing water molecules conserved in multiple uWNK1 crystal structures. Conserved waters are present in two networks, referred to here as conserved water networks 1 and 2 (CWN1 and CWN2). Here, we show that PEG400 applied to crystals of dimeric uWNK1 induces de-dimerization. Both the WNK1 the water networks and the chloride-binding site are disrupted by PEG400. CWN1 is surrounded by a cluster of pan-WNK-conserved charged residues. Here, we mutagenized these charges in WNK3, a highly active WNK isoform kinase domain, and WNK1, the isoform best studied crystallographically. Mutation of E314 in the Activation Loop of WNK3 (WNK3/E314Q and WNK3/E314A, and the homologous WNK1/E388A) enhanced the rate of autophosphorylation, and reduced chloride sensitivity. Other WNK3 mutants reduced the rate of autophosphorylation activity coupled with greater chloride sensitivity than wild-type. The water and chloride regulation thus appear linked. The lower activity of some mutants may reflect effects on catalysis. Crystallography showed that activating mutants introduced conformational changes in similar parts of the structure to those induced by PEG400. WNK activating mutations and crystallography support a role for CWN1 in WNK inhibition consistent with water functioning as an allosteric ligand.

A method is proposed for determining the coefficient of ozone mass transfer between the gas phase and an aqueous solution of HCl + NaCl. The method is based on minimizing the functional of discrepancy between the dependences of the specific reaction rate of O3 with Cl–(aq) on the concentration of hydrogen ions determined from experiment and obtained from reference data. The method also allows estimation of the true Henry constant in acidic solutions of chlorides. [ABSTRACT FROM AUTHOR]

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The viewpoints on whether high concentrations of chloride ion (Cl−) promote or inhibit the oxidation activity of activated persulfates are still inconclusive. Furthermore, the degradation of organic pollutants by the persulfates in the presence of high Cl− concentrations without any activation medium has not yet been studied. In this work, the efficiency and mechanism of degradation of organic pollutants such as carbamazepine (CBZ), sulfadiazine (SDZ), and phenol (PN) by Cl−-activated PMS (denoted as Cl−/PMS) were investigated. Results showed that Cl− could effectively activate PMS for the complete removal of CBZ, SDZ, and PN with reaction kinetic constants of 0.4516 min−1, 0.01753 min−1, and 0.06805 min−1, respectively. Parameters such as PMS dose, Cl− concentration, solution pH, and initial concentrations of organic pollutants that affect the degradation efficiencies of the Cl−/PMS process were optimized. Unlike conventional activated persulfates, it was confirmed that the free chlorine was the main active species in the Cl−/PMS process. Finally, the degradation by-products of CBZ and SDZ as well as their toxicity were detected, and a possible degradation pathway for CBZ and SDZ was proposed. Though higher toxic chlorinated by-products were generated, the Cl−/PMS process was still an efficient oxidation method for the removal of organic pollutants in aqueous solutions which contain high concentrations of Cl−. [ABSTRACT FROM AUTHOR]

It is important to study the steel corrosion inhibition behavior in complex chloride salt environments. This paper uses the fact that calcined layered double hydroxides (CLDHs) have a certain memory effect, which means that it can reabsorb water and anions and partially restore the lamellar structure under certain conditions. This work investigated the influence of cation types on the steel corrosion inhibition behavior of CLDH in saturated calcium hydroxide solution using equilibrium isotherms of Cl− uptake, the electrochemical method, X-ray diffraction (XRD), Fourier-transform infrared (FTIR), and scanning electron microscopy (SEM) techniques. The results show that the corrosion inhibition of the CLDH is affected by the cation types in the following order: Ca2+>Mg2+>K+≈Na+·Na+ and K+ increase the pH of the solution and decrease the corrosion inhibition of CLDH. The addition of Mg2+ can promote the reconstruction of Mg-Al-Zn-Cl hydrotalcite. The addition of Ca2+ can promote the formation of new Ca-Al layered double hydroxide (Ca-Al-LDH) and improve the corrosion inhibition. [ABSTRACT FROM AUTHOR]

Copyright of Metal Working (1674-165X) is the property of Metal Working Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to study the corrosion effect of vitamin corrosion inhibitor in reinforced concrete systems, the effects of thiamine (VitB1), nicotinic acid (VitB3), pyridoxine (VitB6) and ascorbic acid (VitC) on steel reinforcement in simulated pore solutions of concrete containing chlorine was investigated using dynamic potential polarization and electrochemical impedance spectroscopy tests. The mechanism of vitamin corrosion inhibition on steel reinforcement was also discussed based on density general function theory with quantum chemical calculations. The results show that VitB6 has the best corrosion inhibition effect in simulated pore solution of concrete containing 0.05 mol/L NaCl because of the strongest bonding stability between its highest occupied molecular orbital and the 3d orbital of iron. All four vitamins have a specific concentration value to achieve the best corrosion inhibition effect IE. At this time, VitB1 and VitB3 are anodic corrosion inhibitors and VitB6 and VitC are mixed corrosion inhibitors. With the increase of vitamin concentration, the IE tends to fluctuate inversely, which is due to the inhibition of cathodic reaction caused by the adsorption of polar groups on steel surface, further aggravating the imbalance between cathode and anode. [ABSTRACT FROM AUTHOR]

Concrete can be damaged under long‐term chloride ion action. This article uses mineral admixtures to repair the damaged concrete, and then conducts durability performance tests. Multi‐dimensional chloride ion diffusion tests were conducted under different salt solution immersion environments. The resistance of concrete to chloride ion corrosion was evaluated through RCM chloride ion penetration test, and the internal chloride ion concentration of concrete with different diffusion dimensions was detected through chemical titration analysis. Taking the SW test group as an example, after soaking for 3 months, the three‐dimensional diffusion chloride ion concentration of the SW test group is 2.55 times that of the one‐dimensional diffusion. Under the same three‐dimensional diffusion conditions, at a depth of 10 mm of concrete erosion, the chloride ion concentration of the SW test group after soaking for 3 months is 1.76 times that of the chloride ion concentration after soaking for 1 month. Experiments have shown that multi‐dimensional diffusion can significantly increase the concentration of chloride ions inside concrete, and this effect becomes more pronounced with the increase of erosion time and dimension. [ABSTRACT FROM AUTHOR]

This article uses ultra‐high performance concrete (UHPC) to repair damaged concrete and analyzes the durability performance of the repaired concrete. Among them, three erosion solutions with a mass concentration of 2.8% NaCl + 0.29% Na2SO4, 5% NaCl, and 5% NaCl + 10% Na2SO4 were designed to soak the concrete specimens for 1 to 3 months. Taking the SWC test group as an example, when the concrete test block undergoes 30 dry wet cycles and the erosion depth is 20 mm, the difference in chloride ion concentration under different diffusion dimensions is not significant. After 90 dry wet cycles, at a depth of 20 mm, the chloride ion concentration inside the concrete in the three‐dimensional diffusion state reached 3 times that of one‐dimensional diffusion, and the chloride ion concentration in the two‐dimensional diffusion state also reached 2 times that of one‐dimensional diffusion. At a depth of 30 mm, a small amount of chloride ion content was also found in the two‐dimensional diffusion and three‐dimensional diffusion. [ABSTRACT FROM AUTHOR]

River sand was consumed in large quantities, and alternatives to river sand were urgently needed. There are a large number of natural resources of aeolian sand in western China. Aeolian sand was prepared into aeolian sand concrete (ASC). It can greatly reduce the consumption of river sand and inhibit the process of desertification to protect the environment. ASC is a new type of concrete material prepared by using aeolian sand as fine aggregate. To clarify the chloride ion transport behaviour in the ASC under long-term natural immersion, the aeolian sand was 100% substituted for the river sand to prepare the full ASC with three water–binder ratios. The ASC was naturally immersed in 3 and 6% NaCl solutions for a long time, and nuclear magnetic resonance and microscopic scanning electron microscopy techniques were used. The change rule of chloride ion content at different depths of the ASC was studied, and its microstructure characteristics under different erosion times were analysed. The results showed that the free chloride ion concentration at different depths of the ASC increased with increasing water–binder ratio, immersion time, and chloride concentration. After soaking in the salt solution, the hydration products in the ASC reacted with chloride ions to form Friedel salt, which filled the internal pores and microcracks of the ASC, improved its interface transition zone structure, and increased the compactness of the test piece. The porosity of the three groups of ASC with different water–binder ratios decreased by 0.95, 1.03, and 1.15% after soaking in 6% salt solution for 12 m. To study the diffusion law of chloride ions in ASC, combined with influencing factors such as temperature, humidity, D value, deterioration effect and chloride ion combination, Fick’s second law was modified, and a chloride ion diffusion model of ASC with high accuracy was established, with a fitting correlation number above 0.93, which provided a reference for the research and application of ASC in saline areas.

In order to study the corrosion performance of iron-based amorphous alloys in chlorine-containing solution at different temperatures, Fe69.9Cr22.6Mo5.7Cu0.6Zr0.1Nb0.8W0.3 amorphous ribbons were prepared using arc melting combined with vacuum melt spinning. The effect of temperature on corrosion resistance of alloy in chlorine-containing solution was studied by potentiodynamic polarization curves, impedance spectroscopy and immersion tests. Results showed that, compared to 316 stainless steel, the alloy possessed a typical amorphous structure, and its corrosion resistance was significantly enhanced. In a 3.5% (mass fraction) NaCl solution at 25 ℃, the corrosion resistance of its free surface was comparable to that of the roll surface, with the self-corrosion current density being approximately 18.9% and 15.7% of that of 316 stainless steel, respectively. The alloy exhibited stable passivation characteristics in the NaCl solution, but with a wider passivation range ΔE. At 45 ℃ in the NaCl solution, the difference in corrosion resistance between the free surface and the roll surface significantly increased, the self-corrosion current density notably increased, and ΔE showed little change. In a 37% hydrochloric acid solution at 80 ℃, its corrosion rate increased by two orders of magnitude compared to the condition at room temperature, yet it remained significantly lower than that of 316 stainless steel by two orders of magnitude. The increase in temperature led to a rise in the number of active sites on the surface of the amorphous alloy, enhanced the penetration ability of chloride ions, and accelerated the corrosion reaction rate.

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According to the World Health Organization, fluoride in drinking water, either below or above the established permissible range, can adversely affect oral health, including tooth decay and dental fluorosis. The objective of this study was to evaluate fluoride and chloride ion concentration and their health implications in groundwater within Bwari Area Council, Abuja, Nigeria using ion-selective electrode potentiometric titration for fluoride ion and Argentometric titration for chloride ion determinations. The results showed a high fluoride concentration in well water samples ranging from 0.126 mg/L to 0.216 mg/L, compared to borehole water samples ranging from 0.013 mg/mL to 0.052 mg/L. Among the chloride concentrations, the highest levels were observed in the well water sample A (96.09 mg/L), followed by borehole samples, A (63.08 mg/L) and B (49.35 mg/L). The lowest chloride concentration was recorded in the borehole sample H (11.82 mg/L). Notably, both well and borehole water sources in the studied communities had fluoride concentrations below the established minimum WHO standard (0.5 mg/L). The chloride concentrations in the groundwater samples from the study area fell within WHO standards (< 250 mg/L). The results from this study suggest that the continuous consumption of water from these community sources, without additional sources of fluoride, may increase the risk of tooth decay. Therefore, addressing this issue and ensuring appropriate water treatment measures is vital for maintaining optimal oral health in the region. [ABSTRACT FROM AUTHOR]

Copyright of Journal of South China University of Technology (Natural Science Edition) is the property of South China University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As chloride (Cl−) is a commonly found anion in natural water, it has a significant impact on electrocatalytic oxidation processes; yet, the mechanism of radical transformation on different types of anodes remains unexplored. Therefore, this study aims to investigate the influence of chlorine-containing environments on the electrocatalytic degradation performance of levofloxacin using BDD, Ti4O7, and Ru-Ti electrodes. The comparative analysis of the electrode performance demonstrated that the presence of Cl− improved the removal and mineralization efficiency of levofloxacin on all the electrodes. The enhancement was the most pronounced on the Ti4O7 electrode and the least significant on the Ru-Ti electrode. The evaluation experiments and EPR characterization revealed that the increased generation of hydroxyl radicals and active chlorine played a major role in the degradation process, particularly on the Ti4O7 anode. The electrochemical performance tests indicated that the concentration of Cl− affected the oxygen evolution potentials of the electrode and consequently influenced the formation of hydroxyl radicals. This study elucidates the mechanism of Cl− participation in the electrocatalytic degradation of chlorine-containing organic wastewater. Therefore, the highly chlorine-resistant electrocatalytic anode materials hold great potential for the promotion of the practical application of the electrocatalytic treatment of antibiotic wastewater. [ABSTRACT FROM AUTHOR]

Background: Cerebral ischemia–hypoxia leads to excitotoxicity‐mediated neuronal damage and cognitive dysfunction, especially in the elderly. Excessive intracellular [Cl−]i accumulation weakens γ‐aminobutyric acid (GABA) compensatory effects. Sub‐anesthetic dose of propofol protected the brain against ischemia–hypoxia, which was abolished by blocking Cl− efflux transporter K+/Cl− cotransporter 2 (KCC2). We aimed to determine whether low‐dose anesthetic combined with [Cl−]i regulators could restore the compensatory GABAergic system and improve cognitive function. Methods: Chronic cerebral hypoxia (CCH) model was established by bilateral carotid artery ligation in aged rats. Sub‐dose of anesthetics (propofol and sevoflurane) with or without KCC2 agonist N‐ethylmaleimide (NEM) or Na+/K+/Cl− cotransporter 1 (NKCC1) antagonist bumetanide (BTN) was administered systemically 30 days post‐surgery. Primary rat hippocampal neuronal cultures were subjected to hypoxic injury with or without drug treatment. Memory function, hippocampal neuronal survival, GABAergic system functioning, and brain‐derived neurotrophic factor (BDNF) expressions were evaluated. Results: Sub‐anesthetic dose of combined propofol (1.2 μg mL−1) and sevoflurane [0.7 MAC (minimum alveolar concentration)] did not aggravate the hypoxic brain injury in rats or cell damage in neuronal cultures. Adding either BTN or NEM protected against hypoxic injury, associated with improved cognitive function in vivo, less intracellular accumulation of [Cl−]i, reduced cell death, restored GABAergic compensation, and increased BDNF expression both in vivo and in vitro. Conclusion: Sub‐anesthetic dose of propofol and sevoflurane is a recommended anesthesia regimen in at‐risk patients. Restoration of [Cl−]i homeostasis and GABAergic could further reduce the brain damage caused by ischemia–hypoxia. [ABSTRACT FROM AUTHOR]

The issue of ocean corrosion in coastal areas, particularly in concrete structures partially buried in the soil has attracted wide attention has garnered attention due to the unique challenges it presents. This study investigates the enhanced chloride ions intrusion in concrete due to bidirectional unsaturated gradients between the parts buried in soil and those exposed to the air. A 90-day chloride salt erosion experiment was conducted on both fully buried and semi-buried concrete across five different soil environments to analyze the transport properties of chloride ions. Drilling powder sampling and the detection of free chloride ion content in the concrete specimens were performed at intervals of 30, 60, and 90 days. The results indicate that the chloride ions in semi-buried concrete exhibit bidirectional unsaturated migration toward the air-exposed end, leading to significantly peak chloride ion concentrations at the air-exposed end compared to those subjected to wet-dry cycles in a pure salt solution. Specifically, after a 90-day cycle, the total chloride contents at the air-exposed end of semi-buried concrete in pure sandy soil, 50 % clay soil, and pure clay soil increased by 68.8 %, 43.1 %, and 16.4 %, respectively. Soils with lower permeability intensified the vertical unsaturation gradient within the concrete, accelerating chloride ion migration towards the exposed end and resulting in higher accumulation at elevated positions. The research work underscores the critical impact of bi-directional unsaturated transport on concrete durability in coastal environments and calls for a deeper understanding of its applications for corrosion prevention.

Abstract This article uses ultra‐high performance concrete (UHPC) to repair damaged concrete and analyzes the durability performance of the repaired concrete. Among them, three erosion solutions with a mass concentration of 2.8% NaCl + 0.29% Na2SO4, 5% NaCl, and 5% NaCl + 10% Na2SO4 were designed to soak the concrete specimens for 1 to 3 months. Taking the SWC test group as an example, when the concrete test block undergoes 30 dry wet cycles and the erosion depth is 20 mm, the difference in chloride ion concentration under different diffusion dimensions is not significant. After 90 dry wet cycles, at a depth of 20 mm, the chloride ion concentration inside the concrete in the three‐dimensional diffusion state reached 3 times that of one‐dimensional diffusion, and the chloride ion concentration in the two‐dimensional diffusion state also reached 2 times that of one‐dimensional diffusion. At a depth of 30 mm, a small amount of chloride ion content was also found in the two‐dimensional diffusion and three‐dimensional diffusion.

This study evaluates the effectiveness of GN (Graphene Nanoplatelets) salt inhibitor-treated concrete in inhibiting chloride ion diffusion and corrosion compared to untreated concrete under various erosion conditions. Through an accelerated indoor chloride erosion test lasting 180 days, we examined the temporal changes in internal chloride ion concentration with and without the GN salt inhibitor. Quantitative assessment of the inhibitor's impact was achieved by introducing reduction factors for surface chloride concentration and diffusion coefficient. Our findings reveal a significant reduction of 31.3 % in chloride ion diffusion coefficient and 22.67 % in surface chloride concentration in concrete treated with GN salt inhibitor. This indicates the inhibitor's potential to extend the service life of gearbox and substation foundations exposed to chloride ion erosion environments.

Abstract In this study, zirconium oxide nanofiber with a mean diameter of 100 nm was added to concrete at various concentrations as a cement replacement. Various tests, including compressive strength, splitting tensile strength, flexural strength, and electrical resistance tests, as well as a rapid chloride penetration test, were performed on specimens containing zirconium oxide nanofibers for the concrete assessment, and the results were compared to those obtained from control specimens that did not contain nanofibers. The results showed that adding zirconium oxide nanofibers at 135 gr/m3 of concrete yielded a 28-day compressive strength equal to 44.62 MPa, which exhibits a 20.40% increase in strength with respect to the specimen that lacked nanofibers. The flexural strength and splitting tensile strength tests at 28 days of age and in the presence of 135 gr/m3 mentioned nanofibers were increased by 22.28 and 33.47%, respectively, in comparison to the control specimens. Moreover, revealed that at 28 days of age, in the specimens containing 270 gr/m3 zirconium oxide nanofibers, the migration coefficient of chloride ion was reduced by 29.86%, and its electrical resistance was increased by 68.33%. These findings highlight the potential of nanofibers as a promising solution for enhancing the strength and performance of concrete structures.

Objectives. To develop a method for the determination of hypochlorite, chloride, chlorite, chlorate, and perchlorate ions in solution; to determine the limits of detection and quantitation for ClO−, Cl−, ClO2−, ClO3−, and ClO4− ions; to evaluate the applicability of the developed method and its suitability for disinfectant analysis.Methods. Ionic chromatography using a conductometric detection system in isocratic elution mode.Results. The method developed for chromatographic determination of chlorine-containing ions can be used to quantify the content of hypochlorite, chloride, chlorite, chlorate, and perchlorate ions. In isocratic elution mode at 7.5 mM NaOH and a flow rate of 0.4 mL/min, the content of chlorine-containing ions can be determined with high sensitivity. The presented method does not require the use of expensive equipment for the ultrasensitive analysis of the studied compounds.Conclusions. A novel method for the simultaneous determination of hypochlorite, chloride, chlorite, chlorate, and perchlorate ions in case of their combined presence is proposed. The technique can be used to carry out routine control of the content of these disinfectant components during use, increasing their effectiveness at the same time as managing associated toxicological risks.

According to the World Health Organization, fluoride in drinking water, either below or above the established permissible range, can adversely affect oral health, including tooth decay and dental fluorosis. The objective of this study was to evaluate fluoride and chloride ion concentration and their health implications in groundwater within Bwari Area Council, Abuja, Nigeria using ion-selective electrode potentiometric titration for fluoride ion and Argentometric titration for chloride ion determinations. The results showed a high fluoride concentration in well water samples ranging from 0.126 mg/L to 0.216 mg/L, compared to borehole water samples ranging from 0.013 mg/mL to 0.052 mg/L. Among the chloride concentrations, the highest levels were observed in the well water sample A (96.09 mg/L), followed by borehole samples, A (63.08 mg/L) and B (49.35 mg/L). The lowest chloride concentration was recorded in the borehole sample H (11.82 mg/L). Notably, both well and borehole water sources in the studied communities had fluoride concentrations below the established minimum WHO standard (0.5 mg/L). The chloride concentrations in the groundwater samples from the study area fell within WHO standards (< 250 mg/L). The results from this study suggest that the continuous consumption of water from these community sources, without additional sources of fluoride, may increase the risk of tooth decay. Therefore, addressing this issue and ensuring appropriate water treatment measures is vital for maintaining optimal oral health in the region.

This paper focuses on the issues of sour water corrosion, CO2 corrosion, wet H2S corrosion, chloride ion corrosion, and stainless steel chloride stress corrosion cracking in gasification-scrubbing system of coal to hydrogen unit. The on-site corrosion monitoring results show that 15CrMo and 14CrlMo are belong to corrosion-resistant materials, while 06Crl3, S30403, S31603, and S22053 are fully corrosion-resistant materials. The laboratory corrosion evaluation results show that 15CrMo belongs to corrosion-resistant materials at less than 200 °C and non corrosion-resistant materials at not less than 200 °C; 06Crl3 is a good corrosion-resistant material at less than 250 °C, and a corrosion-resistant materials at not less than 250 °C; S30403, S31603, and S22053 are fully corrosion-resistant materials; chloride ions have a promoting effect on the corrosion of Q245R and 15CrMo. Based on the above researches, combined with the actual operation of the unit and engineering experience, a recommended plan for equipment and pipeline material selection has been developed, and corrosion control strategies have been proposed. [ABSTRACT FROM AUTHOR]

In order to find a general corrosive treatment scheme suitable for underground structures in Foshan area, based on the geotechnical investigation of the Phase I project of Foshan Metro Line 4, this study adopted the method of literature research and comparative analysis of specifications to conduct in-depth analysis of the corrosion resistance requirements in different specifications. Furthermore, the existing problems in the GB/T 50476-2019 Durability Design Standard for Concrete Structures were discussed, and combined with the actual situation of the existing Foshan Metro Line 3 and Guangzhou Metro Line 7 West Extension to Shunde section, a set of groundwater corrosion prevention and control design standards suitable for subway structures in Foshan area were carried out. The application results in the early construction site of Foshan Metro Line 4 show that when executed according to the above design standards, the relevant performance indicators meet the regulatory requirements. [ABSTRACT FROM AUTHOR]

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In this paper, the durability of cement mortar prepared with a recycled-concrete fine powder (RFP) was examined; including the analysis of a variety of aspects, such as the carbonization, sulfate attack and chloride ion erosion resistance. The results indicate that the influence of RFP on these three aspects is different. The carbonization depth after 30 days and the chloride diffusion coefficient of mortar containing 10% RFP decreased by 13.3% and 28.19%. With a further increase in the RFP content, interconnected pores formed between the RFP particles, leading to an acceleration of the penetration rate of CO2 and Cl−. When the RFP content was less than 50%, the corrosion resistance coefficient of the compressive strength of the mortar was 0.84–1.05 after 90 days of sulfate attack. But the expansion and cracking of the mortar was effectively alleviated due to decrease of the gypsum production. Scanning electron microscope (SEM) analysis has confirmed that 10% RFP contributes to the formation of a dense microstructure in the cement mortar. [ABSTRACT FROM AUTHOR]

In the petroleum industry, the casing steel is fixed with a cement sheath to ensure reliable service in demanding conditions characterized by high temperature, high pressure, and exposure to multiple types of media. After the hydration of the cement, a porous material is produced with a highly alkaline solution filling the pores, commonly referred to as the pore solution. The casing will form a protective passive film when in contact with a highly alkaline pore solution. Nevertheless, once the cement sheath cracks, chloride ions in the stratum will pass through the cement sheath to the surface of the casing. When chloride ions accumulate to a certain concentration, the passive film will be destroyed, without exerting a protective influence on the substrate. After chloride ions come into direct contact with the casing, the casing is prone to severe failure due to corrosion perforation. The casing failure can cause a blowout outside the casing and even scrapping of the oil well. Controlling casing corrosion and ensuring casing integrity relies on understanding the critical chloride ion concentration that can cause the degradation of the passive film. Therefore, to assess the electrochemical properties and analyze the damage process of the passive film under varying chloride ion concentrations, several characterization techniques were employed. These included potential–time curves (E-t), polarization curves, electrochemical impedance spectroscopy (EIS), and Mott–Schottky curves. In addition, the composition of the passive film on the surface of the P110 casing steel was qualitatively analyzed using X-ray photoelectron spectroscopy (XPS). To further understand the surface morphology of the P110 casing steel, scanning electron microscopy (SEM) was used. [ABSTRACT FROM AUTHOR]

Limestone calcined clay cement (LC3) is rich in aluminates, which can bind many corrosive ions in seawater. The microstructure, hydration, and chloride binding behavior of LC3 prepared using seawater are investigated in this study. Seawater significantly enhances the compressive strength of LC3 paste up to 28 days and further refines the pore structure of LC3. Correspondingly, the promotion of seawater on the hydration of portland cement (PC) paste begins to decrease after 72 h, although it still promotes the hydration of LC3 paste until 200 h. When LC3 paste is prepared using seawater, about 75% of total chloride ions are chemically bound to form Friedel's salts at 28 days and 80% of them are formed at 3 days. Moreover, the free chloride ions content in LC3 paste prepared using seawater is 45.2 mg/100 g paste at 28 days, which is only 28% of that in PC paste prepared using seawater and only 6% of total chloride ions. It shows that LC3 has strong chloride binding ability and great potential for preparing seawater concrete. [ABSTRACT FROM AUTHOR]