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Chloride ions are responsible for triggering severe corrosion in the marine environment. Hence, there is a need to deploy corrosion resistant materials such as hexagonal boron nitride (h-BN) sheet to protect mechanical components operating under such harsh conditions. In this work, a first-principles approach was employed to investigate the effect of fluorine modification on the thermodynamic and kinetic behaviors of oxygen on different kinds of vacancy-defective hexagonal boron nitride (h -BN) in a Cl-containing marine environment. Geometrical and electronic structures were systematically analyzed along with adsorption and diffusion behaviors. The existence of a low energy barrier implies that there is a relatively attenuated ability to inhibit O diffusion for double vacancy V BN - h -BN sheet compared to single vacancy V B - h -BN and V N - h -BN sheets. Interestingly, the fluorine functionalization for three defective h -BN sheet is found to cause an increased energy barrier of O diffusion. The F @ Cl @ V N - h -BN sheet possesses the highest diffusion energy barrier, indicating a superior anti-oxidation property in the marine environment. This study provides some fundamental guidelines for realizing high-performance h -BN sheets for protecting equipment and components used in marine applications. [ABSTRACT FROM AUTHOR]

[Display omitted] Theoretical assessment of Cl-excessive, mixed-halide grain boundaries in hybrid perovskite thin films demonstrates that ordered 3D/2D interfaces along perovskite (100) crystallographic planes are the most energetically favored among other possible cases. [ABSTRACT FROM AUTHOR]

For corrosive chloride solution, an excellent corrosion-resistant coating is required. In this view, introducing graphene oxide-modified Al 2 O 3 , TiO 2 , and MnO 2 in a nickel matrix is a novel strategy for achieving this goal. Electrodeposition is used for manufacturing these nanocomposite coatings. The microstructure, electrochemical corrosion resistance, composition, and contact angle are then thoroughly investigated. Electrochemical results revealed that Ni-GO-TiO 2 nanocomposite coating has a low corrosion current density of 10.86 μA/cm2 and a high charge transfer resistance of 2328 Ω cm2. Furthermore, the Ni-GO-TiO 2 nanocomposite coating outlasts pure nickel films. The mechanism of GO-TiO 2 -promoted nickel corrosion resistance turns out to be that GO-TiO 2 may impede the growth of nickel crystals and make them finer. Furthermore, this coating improves smoothness and reduces pores and cracks, resulting in less damage by chloride ions. Based on these findings, incorporating GO-TiO 2 into nickel coatings may provide insights into preventing corrosion of steel pipelines exposed to chloride ions. [Display omitted] • Nickel coating was reinforced with graphene oxide doped Al 2 O 3 , TiO 2 , and MnO 2. • Composition, crystal size, morphology, and hydrophobicity were compared. • Electrochemical and immersion tests were performed on all coatings. • Ni-GO-TiO 2 exhibited superior barrier performance due to improved properties. [ABSTRACT FROM AUTHOR]

Chloride is the most important anion in ore-forming hydrothermal fluids, and chlorine isotopes are therefore potentially sensitive tracers of the origin and evolution of ore-forming fluids. However, they remain a relatively under-utilized tool in ore deposit geochemistry due to the lack of knowledge of chlorine isotope fractionation during ore-forming processes. Using first-principles density functional theory, this study estimates chlorine isotope fractionation factors for various ore-forming processes. All metal-Cl complexes in hydrothermal fluids are enriched in 37Cl compared to chloride ions, but the change in δ37Cl of the fluid trapped in ore minerals is small after the destabilization of metal-chloride complexes during ore mineral deposition. In the precipitation of evaporite minerals from brine, the sequence of enrichment of the heavy Cl isotope (37Cl) is halite > carnallite > aqueous chloride > kainite > sylvite > bischofite. The results of this study agree with the experimental observations that progressive precipitation of halite from brine lowers the δ37Cl value of the residual fluid until the formation of K-Mg chlorides. In low-temperature deposits, δ37Cl values for fluid inclusions and minerals reflect those of the hydrothermal fluid provenance and the mixing of this fluids with saltwater or basinal brines. In high-temperature magmatic-hydrothermal ore deposits that undergo liquid–vapour phase separation, chlorine isotopes fractionate among phases of silicate melt, vapour and chloride-rich liquid. The considerable range in δ37Cl in fluid inclusions may also reflect fluid mixing and hydrothermal alteration. At ambient temperature, the δ37Cl values may reflect evaporative processes and, in the case of chemical weathering of metallic mineral deposits, may record the supergene enrichment of the metals. This study highlights the use of chlorine isotopes as a new tool for interpreting ore-forming processes. [ABSTRACT FROM AUTHOR]

The efficient treatment of refractory organics in reverse osmosis concentrate (ROC) is a critical issue for achieving emission reduction or even zero emission in the petrochemical industry. A simple and efficient electrocatalytic process was proposed for treating actual petrochemical ROC using a highly active self-assembling Ti/SnO 2 -Sb anode. The Ti/SnO 2 -Sb anode was prepared by using citric acid (CA) and ethylene glycol (EG) as precursors, with a mole ratio of Sn:Sb of 5:1 and a metal salts to CA to EG mole ratio of 1:3:16. The resulting electrode surface had a complete mesh pit structure after calcination at 550 ºC. Several key factors were found to affect the degradation of dissolved organic carbon (DOC), including current density, chloride ion concentration, Fe (II) concentration, and acidity. The presence of chloride ions on the anode surface significantly improved the conversion efficiency of hydroxyl radicals, which played a crucial role in the oxidation of the organics. Additionally, near the cathode, oxidative radicals such as H 2 O 2 and O 2 -∙ were generated, while hydroxyl radicals were produced with the addition of Fe (II) and H+. Under a current density of 20 mA·cm−2, the Ti/SnO 2 -Sb anode achieved a COD removal rate of 94.5% and a DOC removal rate of 43.4%. [Display omitted] [ABSTRACT FROM AUTHOR]

Collagen IV is an essential structural protein in all metazoans. It provides a scaffold for the assembly of basement membranes, a specialized form of extracellular matrix, which anchors and signals cells and provides microscale tensile strength. Defective scaffolds cause basement membrane destabilization and tissue dysfunction. Scaffolds are composed of α-chains that coassemble into triplehelical protomers of distinct chain compositions, which in turn oligomerize into supramolecular scaffolds. Chloride ions mediate the oligomerization via NC1 trimeric domains, forming an NC1 hexamer at the protomer-protomer interface. The chloride concentration-" chloride pressure"-on the outside of cells is a primordial innovation that drives the assembly and dynamic stabilization of collagen IV scaffolds. However, a Cl-independent mechanism is operative in Ctenophora, Ecdysozoa, and Rotifera, which suggests evolutionary adaptations to environmental or tissue conditions. An understanding of these exceptions, such as the example of Drosophila, could shed light onthe fundamentals of how NC1 trimers direct the oligomerization of protomers into scaffolds. Here, we investigated the NC1 assembly of Drosophila. We solved the crystal structure of the NC1 hexamer, determined the chain composition of protomers, and found that Drosophila adapted an evolutionarily unique mechanism of scaffold assembly that requires divalent cations. By studying the Drosophila case we highlighted the mechanistic role of chloride pressure for maintaining functionality of the NC1 domain in humans. Moreover, we discovered that the NC1 trimers encode information for homing protomers to distant tissue locations, providing clues for the development of protein replacement therapy for collagen IV genetic diseases. [ABSTRACT FROM AUTHOR]

• UVA 365 /ClO 2 /NaClO process showed excellent degradation efficiency of CBZ. • The UVA 365 /ClO 2 /NaClO process can effectively control the consumption of oxidants. • The main active species were HO • and Cl • at high ratios of ClO 2. • The UVA 365 /ClO 2 /NaClO process can reduce the formation of chlorate and chlorite. A mixed oxidant of chlorine dioxide (ClO 2) and NaClO was often used in water treatment. A novel UVA-LED (365 nm)-activated mixed ClO 2 /NaClO process was proposed for the degradation of micropollutants in this study. Carbamazepine (CBZ) was selected as the target pollutant. Compared with the UVA 365 /ClO 2 process, the UVA 365 /ClO 2 /NaClO process can improve the degradation of CBZ, with the rate constant increasing from 2.11×10−4 sec−1 to 2.74×10−4 sec−1. In addition, the consumption of oxidants in the UVA 365 /ClO 2 /NaClO process (73.67%) can also be lower than that of UVA 365 /NaClO (86.42%). When the NaClO ratio increased, both the degradation efficiency of CBZ and the consumption of oxidants can increase in the UVA 365 /ClO 2 /NaClO process. The solution pH can affect the contribution of NaClO in the total oxidant ratio. When the pH range of 6.0-8.0, the combination process can generate more active species to promote the degradation of CBZ. The change of active species with oxidant molar ratio was investigated in the UVA 365 /ClO 2 /NaClO process. When ClO 2 acted as the main oxidant, HO• and Cl• were the main active species, while when NaClO was the main oxidant, ClO• played a role in the system. Both chloride ion (Cl–), bicarbonate ion (HCO 3 –), and nitrate ion (NO 3 –) can promote the reaction system. As the concentration of NaClO in the reaction solution increased, the generation of chlorates will decrease. The UVA 365 /ClO 2 /NaClO process can effectively control the formation of volatile disinfection by-products (DBPs), and with the increase of ClO 2 dosage, the formation of DBPs can also decrease. [Display omitted] [ABSTRACT FROM AUTHOR]

• Salt stress reduced growth and physiological attributes of celosia argentea. • Application of Moringa zinc oxide nanoparticles (MZnO-NPs) improved growth attributes and floral characteristics. • Salt stress mitigation was credited to reduced uptake of chloride ions and increase in quantum yield of photosystem II. Soil salinization is a significant environmental risk that affects the production of commercial crops. Celosia argentea is an important medicinal and decorative plant. Keeping in mind the economic importance and salt sensitivity of C. argentea , this study was designed to improve the salinity tolerance of C. argentea. Salt stress reduced growth of C. argentea plants grown in salt stress conditions. The quantum yield of Photosystem II (Phi2) decreased by 15%, 20%, and 30% at 100, 200, and 400 mmol L−1 of Cl− salt, respectively as compared to non-saline conditions. In the present study, we used foliar applications of different concentrations (500, 250, and 100 mg L−1) of green synthesized, Moringa Zinc Oxide nanoparticles (MZnO-NPs) to induce tolerance against Cl-salt in C. argentea. Increasing concentration of Cl-salt considerably reduced growth attributes (shoot and root length, fresh weight and dry weight, leaf area) and floral characteristics (density, length, and diameter) C. argentea, while the little effect on the tissue water content of the plant. Cl-salt declined the soluble component of sugars (60%) and proline (10%), but no effect was found in soluble proteins. Accumulation of toxic ion (Cl) and nutrient (K and NO 3) deficiency was more in the shoot than root tissue of plants exposed to Cl−salt. Cl-salt reduces the carotenoid content and Quantum yield of Photosystem II while enhancing photosynthetic pigments (Chl and b) and PhiNPQ. The foliar applications of MZnO-NPs substantially enhanced the biomass, root length, and flower height of C. argentea under Cl-salt but no positive effect was found in improving water content. All NPs increased the soluble sugar and protein of salinity-treated plant but soluble proline was unaffected. The exogenous treatment of MZnO-NP reduces the Cl uptake while enhancing the nutrient (K, Mg, and NO 3) content in the plant. Moreover, NPs increased photosynthetic pigments, carotenoid content, and Quantum yield of Photosystem II while reducing PhiNPQ. It concluded that MZnO-NPs have the potential to improve the growth and floral property of C. argentea when cultivated with saline resources. [ABSTRACT FROM AUTHOR]

Copper and cobalt from industrial operations build up in the environment, posing a substantial health risk. This study examined how ethylenediaminetetraacetic acid (EDTA), citrate, and chloride ions affected the fluidized bed homogeneous granulation process' (FBHGP) ability to recover both individual and combination of copper and cobalt ions from simulated waste streams. A 99% copper removal and 95% granulation efficiency were attained in copper-based solutions. The soluble copper still present in the solution caused a 4% variation in the removal and granulation efficiencies. There were 99% removal and 99% granulation efficiencies in cobalt-based solutions. When EDTA was present in a copper-based solution, 95% removal and 86% granulation were reached, and for cobalt-based solutions, 95% and 91% were the removal and granulation efficiency, respectively. The presence of citrate in the copper-based solution obtained the removal of 83% and granulation efficiency of 54% at 0.1 MR of citrate to copper. No copper phosphate precipitate was formed when the MR was greater than 0.1. There were 96% removal and 92% granulation efficiency when citrate was present in cobalt-based solutions. The presence of chloride ions in copper solution achieved a 99% removal and 91% granulation efficiency, while in cobalt solutions, 99% removal and 98% granulation efficiency were attained. Solutions with combined copper and cobalt with chloride ions achieved 99% removal and 95% granulation efficiency for copper and 99% removal and 95% granulation efficiency for cobalt. The granule sizes decreased as the MR of the complexing agents to metal, and the concentration of chloride ions increased. The peaks on the XRD pattern exactly matched the peaks of cobalt phosphate hydrate (Co 3 (PO 4) 2 ·8 H 2 O). FBHGP has effectively recovered copper and cobalt from the waste streams of simulated metals. [ABSTRACT FROM AUTHOR]

[Display omitted] The mechanism of the carbon dioxide and alkene oxide reaction catalyzed by the pentagonal-bipyramidal CrIII complex, dichloro[2,6-diacetylpyridine bis(benzoylhydrazone)(1−)] chromium, includes the steps of sequential binding of the epoxide molecule, chloride ion and CO 2 with the catalytic particle and subsequent cyclization, accompanied by dissociation of Cl−. The solvent effect is important for the formation of the cyclic carbonate product. [ABSTRACT FROM AUTHOR]

Massive discharge of ammonia nitrogen wastewater not only causes eutrophication of the water body but also has a toxic effect on humans and living things. How to deal with ammonia nitrogen wastewater is a crucial topic for researchers. Here, a novel catalyst of Pt@Ti–Si where platinum was supported on a composite oxide of titanium oxide (TiO 2) and silicon oxide (SiO 2) via a one-pot method was successfully synthesized for catalytic wet air oxidation (CWAO) of ammonia with a high concentration (more than 2000 ppm). Due to the improved specific surface area of SiO 2 and the excellent acid-base resistance of TiO 2 , the prepared composite oxide-supported platinum catalyst has excellent catalytic performance and good stability for CWAO with a high concentration of ammonia. At 200 °C and the O 2 pressure of 2 MPa for 2 h, the 1%Pt@Ti10–Si1 catalyst has a 96.32% conversion of 2470 ppm ammonia and 97.15% selectivity to N 2 and has good catalytic performance even after five cycles. Under the same reaction conditions, when the chloride concentration in the system is 3000–10000 ppm, the CWAO reaction can be inhibited at an early stage and promote conversion and selectivity at a later stage. The results show that the catalyst has good tolerance to chloride ions, and the treated ammonia nitrogen wastewater can be used for subsequent biochemical processes. Therefore, the developed novel catalyst in this study is effective for the CWAO of highly concentrated ammonia and has potential industrial application value. [Display omitted] [ABSTRACT FROM AUTHOR]

Membrane fouling reduces the performance of membrane processes. In this work, a coupling between anodic oxidation and electrodialysis was designed and studied to prevent and control fouling of the AMX anion exchange membrane during the electrodialysis process. Analysis of the AMX membrane surface by SEM, EDS and ATR-FTIR revealed that the presence of sodium dodecyl benzene sulphonate in the solution led to membrane fouling. The fouling resulted in an increase in the membrane electrical resistance and a decrease in the chloride ion transfer flux through the membrane. It was shown that the combination of anodic oxidation with electrodialysis not only greatly reduces the fouling of the AMX membrane but also removes a persistent organic pollutant present in the effluent to be treated. Furthermore, the study of the effect of certain operating parameters on the membrane fouling and the mineralization of the solution has shown that the increase in the current density of the anodic oxidation leads to a decrease in the membrane electrical resistance and an improvement in the efficiency of mineralization. On the other hand, the application of a current density of 40 mA cm−2, natural pH and Na 2 SO 4 as electrolyte supporting during 120 min of eletrodialysis led to an increase in the electrical resistance of the membrane of only 1.23 times and a strong mineralization of the solution (96 %). [Display omitted] • Ions exchange membranes fouling leads to increased membrane electrical resistance. • Organic membrane fouling affects the transfer of mineral ions. • AO-ED coupling mitiges organic fouling of anions exchange membranes. • AO-ED coupling decreases the COD of the solution in contact with the membrane. • Mineralization efficiency depends on the pH, the current density and the nature of the supporting electrolyte. [ABSTRACT FROM AUTHOR]

• CWAO achieved high TOC removal in high-salinity high-organic wastewater. • A salt-tolerant catalyst LaFe0.85Ru0.15O3-δ was developed in CWAO process. • TOC removal of LaFe0.85Ru0.15O3-δ is 45.51% better than the commercial catalyst. • LaFe0.85Ru0.15O3-δ has novel Cl− resistance no matter the concentration of Cl−. • Fe site can adsorb Cl− to protect Ru site and oxygen species to exert catalytic activity. Catalytic wet air oxidation (CWAO) coupled desalination technology provides a possibility for the effective and economic degradation of high salinity and high organic wastewater. Chloride widely occurs in natural and wastewaters, and its high content jeopardizes the efficacy of Advanced oxidation process (AOPs). Thus, a novel chlorine ion resistant catalyst B-site Ru doped LaFe 1- x Ru x O 3-δ in CWAO treatment of chlorine ion wastewater was examined. Especially, LaFe 0.85 Ru 0.15 O 3-δ was 45.5% better than that of the 6%RuO 2 @TiO 2 (commercial carrier) on total organic carbon (TOC) removal. Also, doped catalysts LaFe 1- x Ru x O 3-δ showed better activity than supported catalysts RuO 2 @LaFeO 3 and RuO 2 @TiO 2 with the same Ru content. Moreover, LaFe 0.85 Ru 0.15 O 3-δ has novel chlorine ion resistance no matter the concentration of Cl− and no Ru dissolves after the reaction. X-ray diffraction (XRD) refinement, X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM), and X-ray absorption fine structure (XAFS) measurements verified the structure of LaFe 0.85 Ru 0.15 O 3-δ. Kinetic data and density functional theory (DFT) proved that Fe is the site of acetic acid oxidation and adsorption of chloride ions. The existence of Fe in LaFe 0.85 Ru 0.15 O 3-δ could adsorb chlorine ion (catalytic activity inhibitor), which can protect the Ru site and other active oxygen species to exert catalytic activity. This work is essential for the development of chloride-resistant catalyst in CWAO. [Display omitted] [ABSTRACT FROM AUTHOR]

A dinuclear complex, [PtRhCl 2 (piam) 2 (en)(PPh 3)]PF 6 (2(PPh 3)·PF 6 , where en = ethylenediamine, piam = pivalamidate), arranged in a Pt–Rh–P alignment with metal–metal bonds, has been synthesized and characterized. The affinity of 2(PPh 3)·PF 6 for Cl− ions at the axial Pt site is found to be lower compared to that with NH 3 as a co-ligand. This difference is attributed to the hindrance caused by the en ligand, indirectly supporting the effective formation of multinuclear complexes with the second metal via hydrogen bonds with NH 3. [Display omitted] • Platinum and rhodium dinuclear complex containing ethylenediamine as co-ligand and PPh 3 is prepared. • Two crystal structures contacting axial platinum sites with PF 6 − or Cl− were obtained. • The binding capability for Cl− ion is smaller than that with NH 3 as a co-ligand. In this study, the binding capability for Cl− ion was investigated with amidate-bridged platinum–rhodium dinuclear complex axially coordinated PPh 3 to the rhodium atoms containing ethylenediamine (=en) as co-ligand. Mixing [PtRhCl 3 (piam) 2 (en)]·3H 2 O (2Cl) with PPh 3 and NaPF 6 provided [PtRhCl 2 (piam) 2 (en)(PPh 3)]PF 6 (2(PPh 3)·PF 6) which can bind Cl− ion at the axial position of platinum atom to be [PtRhCl 2 (piam) 2 (en)(PPh 3)]Cl (2(PPh 3)·Cl), where both crystal structures were determined by single-crystal X-ray analyses. UV–vis titration demonstrated that the formation constant of 2(PPh 3)·PF 6 with Cl− is 1.6 × 103 M−1, significantly smaller than that with NH 3 as a co-ligand, which suggests that multinucleation is necessary for effective hydrogen bonds as well as the affinity of metals. [ABSTRACT FROM AUTHOR]

[Display omitted] • The existing form of chloride ion in ZB-233 particles was determined. • Synergistic coupling technology to remove chloride ion. • The chlorine removal efficiency can reach more than 94.03 %. • The purified ZB-233 meets the electronic flame retardant standard. High-quality, low-chloride zinc borate is a low-smoke, non-toxic and environmentally friendly flame retardant with improved electrical properties for printed circuit board (PCB), so it can be used as a new type of flame retardant to replace brominated flame retardants. However, the chlorine content of zinc borate itself is high, and long-term use of zinc borate circuit boards will cause leakage and may cause a fire. To solve this problem, commercially available zinc borate (analytically pure) with a high chlorine content was used for the study. The presence of chloride ions in zinc borate was determined by X-ray photoelectron spectroscopy (XPS) and point of zero charge (PZC) and found to be mainly in the form of soluble salts and electrostatic adsorption. Based on the existing form of chloride ions, the synergistic technology of electrodialysis and washing with Na 2 CO 3 solutions was used to remove most of the chloride ions from zinc borate, and the removal effect was up to 94.03%. The optimal process was optimized by the reaction surface curve method, the separation kinetics and electrical properties were investigated, and the membrane lifetime was evaluated. Zinc borate can be used as a flame retardant in printed circuit boards after contrast treatment. This study provides an important reference and guide for the removal of impurity ions from other inorganic flame retardants. In addition, it provides technical support for the production of high-quality zinc borate flame retardants. [ABSTRACT FROM AUTHOR]

In this paper, the effects of chloride ions, oxygen, and carbon dioxide on the corrosion resistance of passive films formed on 316 L stainless steel were investigated in the aggressive oilfield environment using electrochemical testing and microscopic characterization techniques. The results showed that Cl− accelerated the anodic dissolution of the metal and compromised the structure and densification of the passive film, thus reducing its corrosion resistance. An increase in the partial pressure of carbon dioxide initially promotes pitting, but subsequently inhibited further corrosion development. The presence of oxygen enhanced the cathodic reaction and passive film formation, effectively preventing the invasion of aggressive chloride ions, thus inhibiting further corrosion. These findings provide a significant scientific basis for material selection and protection of oil extraction equipment in oilfield environments. [ABSTRACT FROM AUTHOR]

This study investigates the impact of continuous loading treatment during the curing period on the durability of recycled coarse aggregate concrete with a high replacement ratio. Evaluations were conducted on key parameters including compressive strength, and several durability indicators such as chloride ion permeability, freeze-thaw resistance, and carbonation resistance. Microscale examinations, involving air void structure, microhardness, hydration products, and microstructures, were also performed. The results demonstrate that continuous loading treatment significantly enhanced compressive strength by 4.13%–26.34%, reduced the chloride ion migration coefficient by 14.89%–38.30%, and improved freeze-thaw cycles by 20%. These performance improvements are primarily attributed to the optimized pore structure and strengthened interfacial transition zone. Additionally, this method presents a promising an eco-friendly approach for producing high-durability prefabricated concrete components. [ABSTRACT FROM AUTHOR]

The application of electrochemical methods for incorporating uranium into the magnetite lattice has demonstrated efficacy and durability in remediating radioactive contamination. However, the impact of different ions, particularly electrolyte ions, on this process remains unclear. Herein, we successfully achieved simultaneous magnetite crystallization and uranium incorporation within an electrochemical system using an iron anode. Chloride ions have been identified as having a pivotal role in the generation of ferrous ions via pitting corrosion, thereby establishing an advantageous reducing environment that promotes the transformation of γ-FeOOH to magnetite. Unlike the surface adsorption process of γ-FeOOH, magnetite predominantly eradicates uranium through an incorporation mechanism. Consequently, the existence of chloride ions markedly boosts the effectiveness of uranium elimination and the stability of the resultant substance. Specifically, under conditions of a pH of 5 and a chloride ions concentration of 18 mM, uranium removal reaches nearly 100%. Additionally, findings from uranium leaching experiments indicate that γ-FeOOH removed 25.4% stable, 63.57% metastable, and 11.03% unstable uranium, while magnetite removed 60.35% stable, 24.81% metastable, and 14.84% unstable uranium. This research offers insight into the potential role of electrolyte ions in facilitating in-situ electric-induced uranium incorporation. [Display omitted] • Cl− destroy the oxide film of iron electrode by pitting corrosion and promote Fe2+ production. • Cl− promote the conversion of intermediate product γ-FeOOH to magnetite. • Cl− enhanced the efficiency of uranium removal and the stability of the resulting product. • The enhanced uranium removal mechanism by Cl− was proposed. [ABSTRACT FROM AUTHOR]

• Negatively charged MIP effectively inhibited Cl− interference in photocatalytic process. • MIP effectively suppressed the production of chlorinated byproducts. • This is mainly benefited from synergy of electrostatic repulsion and steric hindrance. • MIP suppressed RCS production and its involvement in photocatalytic reaction. • MIP exhibited good adaptability to various water quality conditions. The ubiquitous chloride ions (Cl−) in water seriously interfere with pollutant oxidation and inevitably generate undesirable chlorinated byproducts. In this study, we report for the first time that a negatively charged molecularly imprinted photocatalyst (MIP) can effectively inhibit Cl− interference and suppress the production of chlorination byproducts (the yield of chloroacetic acid was only 16 % of the bare photocatalyst system) while ensuring efficient degradation of target pollutants, thereby greatly improving the safety of the pollutant degradation process. Taking antibiotics as target pollutant, we investigated the mechanism of action of MIP by comparing the antibiotic degradation pathways, fate of photogenerated active species and production of reactive chlorine species (RCS) in the MIP and bare photocatalyst system. The mechanism by which MIP inhibits Cl− interference was mainly based on a synergy between electrostatic repulsion and steric hindrance induced by the specific capture of antibiotics in imprinted cavity, which effectively suppressed the production of RCS and hindered the participation of RCS in antibiotics degradation. In addition, MIP showed good compatibility with common cations, anions and organic matter, and performed well within a broad pH range in various water environments. Thus, the negatively charged MIP provides a feasible approach for the safe and efficient removal of pollutants in Cl− containing water. [Display omitted] [ABSTRACT FROM AUTHOR]

• Stronger interactions compared to other DES components are observed in the case of chloride anion and the CO 2 molecule according to DFT. • At the same time, stronger N H Cl and O H Cl H-bonds were observed Cl− and as a result, the Cl- was found to be unable to interact with the CO 2 molecule. • The surface layer is shown to be fairly extensive and to contain DES and CO 2 molecules. Quantum chemical DFT calculations [B3LYP+GD3/6-311++g(2d,2p)] of the structure and interactions in various complexes of CO 2 molecule with a choline cation, a chloride anion, urea molecules, a choline chloride ion pair and a 1:2 choline chloride – urea complex were carried out. The contributions of Coulomb and van der Waals interactions were calculated. The QTAIM method was used to evaluate the strength of various bonds. A molecular dynamics simulation of CO 2 molecules in reline in the NPT ensemble (1 atm, 298 K) was also carried out. The radial distribution functions of the particle centers of mass, local mole fraction functions, spatial distribution functions, and density profiles were calculated. Stronger interactions, compared to the other DES components, were observed in case of the chloride anion and the CO 2 molecule according to the DFT calculations. However, in the system, stronger interactions were observed between the chloride anion and the system components, namely N H Cl and O H Cl hydrogen bonds. This made the chloride anion inaccessible and unable to interact with the CO 2 molecule, according to the MD simulation results. Additionally, the presence of a fairly extensive surface layer containing DES and CO 2 molecules was shown. [ABSTRACT FROM AUTHOR]

The hanger steel wires of suspension bridge are suffering serious electrochemical corrosion in harsh marine rainfall environment. This article investigates the application of the electrochemical anti-corrosion method to unsheathed hanger steel wires utilizing rainwater conductivity. The influence of aggressive chloride ions and applied current density on corrosion behavior and protection efficiency was experimentally studied. Results indicate that in simulated marine rainfall environment, the corrosion rate of hanger steel wires increases with chloride ion concentration. Furthermore, chloride ions enhance the electrochemical anti-corrosion efficiency by raising rainwater electrolyte conductivity. Protection efficiency increases with applied current density, and the increase rate gradually decreases in the range of 0–100 mA/m2. Protection efficiency can exceed 37% compared to unprotected steel wire with acceptable applied current density. The corrosion resistance of hanger steel wire significantly enhanced due to the denser, flatter, and more intact corrosion products layer formed on the steel wire surface, and the area near the cathodic access point is best protected. The suitable applied current density decreases with increasing chloride concentration; in marine rainfall environment with 1% NaCl solution, the suitable applied current density is approximately 100 mA/m2, while in environment with 3.5% NaCl solution, this range is around 50–100 mA/m2. • Investigated the electrochemical anti-corrosion of the unsheathed steel wire in a simulated marine rainfall environment. • Optimized the applied current density range of hanger steel wire in marine rainfall environment. • Protection efficiency can exceed 37% compared to unprotected steel wire with acceptable applied current density. [ABSTRACT FROM AUTHOR]

Reaction of Zn(II) and Cu(II) bromide and chloride with 2-(aminomethyl)aniline produced a family of 4-, 5- and 6-coordinate complexes. All zinc compounds exhibit monodentate coordination through the aminomethyl group, while the copper complexes exhibit chelation of the 2-(aminomethyl)aniline. [Display omitted] The syntheses and structures of 2-(aminomethyl)aniline (2-AMAn) complexes of CuX 2 and ZnX 2 (X = Cl, Br) are reported: [(2-AMAn)ZnCl 2 ] (1), [(2-AMAn)ZnBr 2 ] (2), [(2-AMAn) 2 ZnCl 2 ] (3), [(2-AMAn) 2 ZnBr 2 ] (4), [(2-AMAn) 2 CuCl]Cl (5) and [(2-AMAn) 2 Cu(H 2 O) 2 ]Br 2 (6). Compounds 1 and 2 are isomorphous and crystallize in the monoclinic space group Ia with two coordinated halide ions and one chelating 2-AMAn ligand. Compounds 3 and 4 are also isomorphous and crystallize in the monoclinic space group P 2 1 / n with two monodentate 2-AMAn ligands and two coordinated halide ions. All four Zn(II) complexes are slightly distorted tetrahedral in geometry. The Cu(II) complexes are structurally distinct from the Zn(II) complexes. 5 crystallizes in the monoclinic space group P 2 1 / n and is strongly distorted square pyramidal in geometry with two chelating 2-AMAn ligands, one coordinated chloride ion and one dissociated chloride ion. The bromide compound, 6 , crystallizes in the monoclinic space group P 2 1 / c , also with two chelating 2-AMAn ligands, but with two coordinated water molecules and both bromide ions dissociated in the lattice. [ABSTRACT FROM AUTHOR]

[Display omitted] • PDS activated by Fe inductive electrode was introduced to the electrochemical system. • Harmless removal of NH 4 + and recovery of phosphorus as FePO 4 were largely enhanced. • The pathway of NH 4 + oxidation by Cl radicals and PO 4 3− precipitation were proposed. • Efficiency analysis for actual wastewater treatment was presented. Herein, peroxydisulfate (PDS) was introduced to the electrochemical (EC) system, which consisted of a Ti/RuO 2 anode, a Ti cathode, and an Fe inductive electrode (EC/PDS system). A significant enhancement for removal of ammonia nitrogen (NH 4 +) and orthophosphate (PO 4 3−) was observed in this system, while simultaneously recovery of phosphorus (P). Specifically, the removal efficiency of NH 4 + was increased from 53 % to 100 % and the removal efficiency of PO 4 3− was increased from 66 % to 100 % with 5 mM PDS addition (initial NH 4 +-N concentration, 100 mg/L; initial PO 4 3−-P concentration, 10 mg/L; initial Cl− concentration, 100 mM; cell voltage, 2.5 V; reaction time, 60 min; initial pH, 3.0). Under these conditions, NH 4 + was harmlessly removed in the form of nitrogen (N 2) by chloride radicals (Cl) generated via the reaction of sulfate radical (SO 4 −) with chloride ions (Cl−). PO 4 3− was combined with Fe3+ generated by the Fe inductive electrode to form FePO 4 precipitates, achieving P recovery. This system demonstrated superior stability in cycling experiments. The performance for treatment of actual wastewater via this system showed completely harmless removal of NH 4 + and simultaneously recovery of PO 4 3− as FePO 4. This study can provide reference for the treatment of wastewater containing NH 4 + and PO 4 3−. [ABSTRACT FROM AUTHOR]

• The small sample data temperature compensation of chloride ion probe was proposed. • An improved adaptive BP neural network algorithm was designed. • The Black Widow Optimization Algorithm was combined with BP neural network. • The improved model achieves good recognition accuracy (1.21% relative error). Fiber optic sensors have great applied in the field of sensing, however they are subject to temperature. In this study, we proposed an improved small sample data Back Propagating (BP) neural network for temperature compensation of a chloride ion probe based on an optical fiber Fabry-Perot interferometer (FPI). The temperature compensation results show that the Black Widow Optimization (BWO) algorithm was combined with BP neural network to further improve the performance of the model with a great detection accuracy that the relative error is 1.21%, associated with a Mean Square Error (MSE) of 2.6e−5.This is an excellent temperature compensation method with low computational cost and small samples. [ABSTRACT FROM AUTHOR]

• Created an environment-specific model using historical environmental data and considering GBA-based exposure conditions. • The surrogate model surpasses alternative models with over 99% accuracy across all target variables and scenarios. • Physical and environmental factors' evolving impact on durability and mechanical measurements is disclosed over time. • Impact of global warming on coastal structures underscores non-linear and discrete effects of diverse factors. Long-term exposure to coastal and marine environments accelerates the aging of reinforced concrete (RC) structures, impacting their structural safety and society impact. Traditional assessments of long-term performance deterioration in RC structures involve complex, nonlinear, and time-intensive studies of physical mechanisms. While existing machine learning (ML) methods can assess the lifetime of these structures, they often prioritize data regression over mechanistic interpretation. To enhance the efficiency and interpretability of predicting the life-cycle performance of RC structures, this study introduces a generic framework based on interpretable ensemble learning (EL) methods. The framework predicts life-cycle performance efficiently and accurately, with optimal hyperparameters automatically tuned through Bayesian optimization. Interpretability algorithms clarify the influence of environmental, durability, and mechanical parameters on structural durability and mechanical predictions. Validation employs real-world cases of RC hollow beams in the coastal area of the Guangdong-Hong Kong-Macao Greater Bay Area (GBA). The comprehensive model for RC structures integrates actual data on temperature, humidity, and surface chloride content in the GBA, considering diffusion, convection, and binding effects of chloride ions, corrosion non-uniformity, and crack impact on durability estimation. Comparative analysis with existing ML methods underscores the effectiveness of the framework. The findings highlight the dynamic evolution of feature importance rankings throughout the service life, shedding light on the continuous changes in the significance of different factors when predicting mechanical resistance. [ABSTRACT FROM AUTHOR]

• DFT calculations were used to guide the deprotonated BTA (BTA−) intercalated LDH interlayer. • LDH within PVDF/LDH@BTA− captured up to 0.26 mmol/cm2 of chloride ions through anion exchange. • Adsorption mechanism of Cl− into LDH interlayer was investigated by MD simulation and experimental demonstration. • PVDF/LDH@BTA− composite nanofibers significantly enhanced anticorrosion performance for epoxy. To enhance corrosion resistance and extend the service life of coatings, layered double hydroxides (LDH) have been embedded into coatings to create a hybrid of organic–inorganic micro/nano-containers, improving the coatings' physical barrier properties. Herein, an elaborately designed strategy is proposed to in-situ grow LDH on nanofibers, thereby obtaining polyvinylidene difluoride/hydrotalcite@deprotonated benzotriazole (PVDF/LDH@BTA−) composite nanofibers, followed by incorporation into an epoxy resin to formulate the composite coating. The even distribution of LDH within the coating, aided by nanofibers, significantly bolstered the coating's barrier effect. Upon exposure to corrosive environments, the hydrotalcite structure within PVDF/LDH@BTA− adsorbs chloride ions through anion exchange, capturing up to 0.26 mmol/cm2 of chloride ions. Concurrently, corrosion inhibitors were released, forming a protective layer on the copper surface to substantially mitigate the corrosion process. This innovative approach markedly enhances the composite coating's long-term corrosion resistance. [ABSTRACT FROM AUTHOR]

In marine environments, traditional ordinary Portland cement (OPC) and reinforced concrete structures are prone to corrosion, reducing their durability and service life dramatically. Geopolymers, with exceptional corrosion resistance, have great value and application potential in marine engineering. This paper presents a comprehensive overview of the research advances on geopolymer cements and concretes in marine environments in terms of mechanical properties, durability, and structural properties. The research so far has demonstrated that geopolymers exhibit superior mechanical properties and durability due to their denser interface and lower porosity compared to OPC. However, geopolymers have significant brittleness defects, and their performance in marine environments, especially in splash and tidal zones with alternating wet and dry conditions, is severely affected. This is due to the influence of chloride ions, divalent cations, pH, and sulfate in seawater, which promote or inhibit the formation and transformation of reaction products and microstructures, thereby affecting their mechanical properties and stability. Nevertheless, the use of composite technologies such as modified precursors, fibers, and nanomaterials has a positive effect on enhancing their structural properties and durability. This provides guidance and solutions for the application of high-durability, low-carbon emission, and more sustainable building materials in maritime engineering. [ABSTRACT FROM AUTHOR]

Nanocontainers encapsulating corrosion inhibitors are commonly incorporated into organic coatings to enable self-healing effects, thereby ensuring long-term anticorrosion performance. In this study, a novel dual corrosion inhibitor-loaded self-healing nanocontainer with core-shell structure was proposed for fabricating composite waterborne epoxy coatings with both active and passive corrosion prevention properties. The nanocontainer, named BTA-ZIF-8@LDH-Mo, was synthesized through the in-situ growth of molybdate-intercalated ZnAl layered double hydroxide (LDH-Mo) on the surface of 1H-benzotriazole-inbuilt zeolitic imidazolate framework (BTA-ZIF-8). Potentiodynamic polarization results showed that the I corr of bare Q235 carbon steel immersed in a 3.5 wt% NaCl solution decreased from 4.658 × 10−6 A/cm2 to 1.274 × 10−6 A/cm2 after introducing BTA-ZIF-8@LDH-Mo nanocontainers, resulting in a superior corrosion inhibition efficiency of 72.65 %. Electrochemical impedance spectroscopy further demonstrated that the |Z| f=0.01Hz of epoxy coating doped with BTA-ZIF-8@LDH-Mo reached 4.24 × 109 Ω·cm2 after 42 d of immersion in 3.5 wt% NaCl solution, approximately 30 times higher than that of pure EP coating. Moreover, investigations on artificially scratched coatings indicated that the incorporation of BTA-ZIF-8@LDH-Mo nanocontainers effectively mitigated the corrosion process by forming an inhibiting layer on the metal substrate that impeded the corrosion process. The dual corrosion inhibitor strategy relies on the synergistic action of BTA pre-loaded in ZIF-8 nanoparticles and molybdate (MoO 4 2-) intercalated in LDH interlayers for active corrosion protection. Additionally, the nanocontainers enhance passive protection by elongating the diffusion paths of corrosive media and trapping chloride ions. This nanocontainer design offers a facile strategy for fabricating a smart coating with the excellent anticorrosion properties. • BTA-ZIF-8@LDH-Mo core-shell structured nanocontainers were prepared. • Resulted nanocontainers exhibited effective dual inhibitor release. • The nanocontainers provide both active and passive corrosion protection for waterborne epoxy coating. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesis of octahedral manganese(II) complexes with different anions such as chloride, perchlorate, and tosylate. • Pyrazolo[1,5-a][1,10]phenanthroline-3-carbonitrile is used as bidentate ligand. • Manganese(II) complexes exhibit a white-green emission in the microsecond range with maxima at 530–565 nm in the solid state. • Comparison of the luminescence of pyrazolo[1,5-a][1,10]phenanthroline-3-carbonitrile-based manganese(II) complexes with unsubstituted 1,10-phenanthroline. Five manganese(II) complexes with a bidentate pyrazolo[1,5-a][1,10]phenanthroline-3-carbonitrile ligand (L) have been prepared and their structures have been determined. The anion effect on the structural diversity of the complexes has been studied using manganese(II) salts with different anions such as Cl¯, ClO 4 ¯, and Ts¯. A reaction between manganese(II) chloride and L in organic solvents leads to complexes [MnL 2 Cl 2 ]·xCH 2 Cl 2 (1) and [Mn 2 L 2 (H 2 O)Cl 4 ]·L (2), the use of manganese(II) tosylate in the rection yields in [MnL(H 2 O) 3 Ts]Ts·L·H 2 O (3) and [MnL(H 2 O) 3 Ts]Ts (4), and finally, in the case of manganese(II) perchlorate [MnL 2 (H 2 O) 2 ](ClO 4) 2 ·L (5) is formed. According to the single-crystal X-ray analysis the coordination environment of the Mn(II) ions in the complexes is a distorted octahedron with MnN 4 Cl 2 (1), MnN 2 O 4 (3) and MnN 4 O 2 (5) chromophores; the complex 2 is binuclear, in which two manganese atoms have different coordination geometries – distorted octahedron (MnN 2 Cl 3 O) and square pyramid (MnN 2 Cl 3). Chloride ions are coordinated anions; perchlorate ions are in the outer coordination sphere. Tosylate ions can play both coordinating and non-coordinating roles in complexes. X-ray analysis shows that in 2 and 5 one molecule of L has no bonds with manganese atoms, and reveals only intermolecular interactions through π-π stacking. This leads to the formation of cocrystals [Mn 2 L 2 (H 2 O)Cl 4 ]·L or [MnL 2 (H 2 O) 2 ](ClO 4) 2 ·L, that affects the photophysical properties of these compounds. In order to compare the effect of L coordination on the photoluminescence properties of manganese(II) complexes, the complexes [Mn(phen) 3 ](ClO 4) 2 ·xSolv with unsubstituted 1,10-phenanthroline have been synthesized. In contrast to [MnL 2 (H 2 O) 2 ](ClO 4) 2 ·L, the 1,10-phenanthroline-based compound [Mn(phen) 3 ](ClO 4) 2 ·H 2 O has no emission. Complexes 1, 3, 4 and 5 exhibit a white-green emission in the microsecond range with maxima at 530–565 nm in the solid state, and the photoluminescence properties of 5 are studied in solution. [ABSTRACT FROM AUTHOR]

The airway epithelium is located at the interactional boundary between the external and internal environments of the organism and is often exposed to harmful environmental stimuli. Inflammatory response that occurs after airway epithelial stress is the basis of many lung and systemic diseases. Chloride intracellular channel 4 (CLIC4) is abundantly expressed in epithelial cells. The purpose of this study was to investigate whether CLIC4 is involved in the regulation of lipopolysaccharide (LPS)-induced inflammatory response in airway epithelial cells and to clarify its potential mechanism. Our results showed that LPS induced inflammatory response and decreased CLIC4 levels in vivo and in vitro. CLIC4 silencing aggravated the inflammatory response in epithelial cells, while overexpression of CLIC4 combined with LPS exposure significantly decreased the inflammatory response compared with cells exposed to LPS without CLIC4 overexpression. By labeling intracellular chloride ions with chloride fluorescent probe MQAE, we showed that CLIC4 mediated intracellular chloride ion-regulated LPS-induced cellular inflammatory response. [Display omitted] • LPS induces inflammatory response and decreases CLIC4 levels in vivo and in vitro. • CLIC4 inhibits LPS-induced inflammatory response in HBECs. • CLIC4 mediates intracellular chloride ion-regulated LPS-induced cellular inflammatory response. [ABSTRACT FROM AUTHOR]

Selective oxidation of water without production of chlorine during the electrolysis of seawater is a critical impediment towards obtaining green hydrogen. Indeed, understanding the complex competitive mechanisms of oxygen and chlorine formation at the anode is an analytic challenge. An argument for direct seawater electrolysis is presented with a dissection of the complications that arise at the anode in the presence of seawater ionic constituents such as the chloride ion. Electrolyser system durability and the impact on the current and voltage efficiencies are discussed. Critical challenges at the anode under the acidic conditions of proton exchange membrane water electrolysis interrelate the thermodynamic and kinetic constraints of the oxygen evolution reaction (OER) and the chlorine evolution reaction (CER) to elucidate the heterogenous mechanisms of the OER and the CER and the crucial stability predicament under selective OER electrocatalysis. The selectivity circumstances resolved by Density Functional Theory computations shed insight onto the reaction conditions that select for the preferred OER adsorbate chemisorption on the surface and substantiates the observed overpotentials required for the OER and CER; experimental rotating ring disk electrode analysis further indicate competitive adsorption of OER and CER reactants under an assumed Langmuir isotherm model. Identifying the rate determining step and breaking the scaling relationship of the AEM OER pathway may both improve the stability of the catalyst and achieve lower OER overpotentials. Critical insight is given into designing the heterogeneous electrocatalyst structure with selective facets, additional point defects, and augmented active site density through single atom catalysts. An argument for the utilization of ruthenium for its high natural ubiquity and modulable valence states that can facilitate atomic configurations with optimal active site d-band center energies to promote selective adsorbate binding is presented. Studies of in-situ filtration of the chloride ion under acidic conditions highlight the utility of manganese oxide and silica; the augmentation of the conductivity through manipulation of polaronic interactions; and the design of heterogeneous electrocatalysts with self-healing characteristics demonstrated in select molecular catalysts that may decrease the overpotential of the OER and achieve selectivity. It is with the hope that these design strategies provide insights into future research efforts to uncover an electrocatalytic surface selective for OER evolution under the perilous acidic conditions and reveal an effective solution as serendipitous as the abundancy of a natural resource such as seawater. [ABSTRACT FROM AUTHOR]

In order to study the corrosion behavior of concrete box girder in deicing salt environment, a series scaled model of concrete box girders were made to study the deterioration mode of concrete box girder under load, chloride corrosion, freeze-thaw cycle and their combined action. Combined with silane impregnation, the durability protection technology of concrete box girder bridges in cold regions was proposed. The experimental results show that under freezing-thawing action, the top plate of the box girder has the most serious deterioration, and the performance of the web is better. The surface erosion of the top plate is 65.38 % and 80.77 % different from that of the bottom plate and web plate, respectively. The freezing-thawing erosion of the concrete box girder has a significant spatial multi-dimension. The chloride ion erosion law of the top plate and bottom plate of concrete box girder is similar to the distribution law of shear lag effect under load. The inhibition effect of compressive stress on chloride ion is 9.67 %, and the overall inhibition effect is not large. The maximum difference of chloride ion concentration at each measuring point on the bottom plate is 30.14 %. Silane can be used as a protective coating for concrete bridges in cold areas, and the coating thickness of 2 mm can meet the requirements of anti-freezing. With the increase of freeze-thaw time, the silane protection ability began to decline. The maximum silane protection effect of 0–1 cm from the surface at 90d and 180d decreased by 40.8 % and 71.7 %, respectively. After the silane coating was applied, the chloride ion erosion rate of the bottom plate still showed a faster trend. When the freeze-thaw cycle exceeded 30 times, the silane protection ability decreased almost at a linear rate with the freeze-thaw time. Regardless of whether the silane coating protection technology is adopted, the chloride ion concentration of the bottom plate of concrete box girders is at least 10 % more than that of the top plate for freeze-thawing 90d and 180d, and the maximum can reach 32.1 %. The deterioration behavior of concrete box girders in cold regions has significant spatial multi-dimension. The existing single-parameter durability design methods, which mainly focus on solid section, are no longer suitable for box girder structures. • The corrosion mode of concrete box girder has significant spatial multidimensional characteristics • The single parameter durability design method is not fully applicable to box girders. • A silane coatingcoating of 2 mm can meet the frost resistance requirements of concrete bridges in cold regions • Silane coatings had good frost resistance in the early. stages of service. [ABSTRACT FROM AUTHOR]

The significance of the chloride ion diffusion rate cannot be overstated when evaluating the durability of concrete structures. Nonetheless, conventional techniques employed for determining the chloride ion diffusion coefficient in concrete, particularly in the case of seawater and sand concrete (SSC), are prone to inaccuracies due to the inherently elevated levels of inherent chloride ions present within SSC. This research introduces a fresh approach for precisely ascertaining the chloride ion diffusion rate within SSC, addressing this issue. Based on the ion concentration gradient conversion mechanism, an exfiltration method was established, and a corresponding apparatus was developed. The study also investigates the effects of W/C, fly ash content, and LC2 content on chloride ion leaching behavior of SSC. Additionally, the determination of the chloride ion diffusion coefficient and the evaluation of SSC's resistance to chloride ingress were carried out by employing Fick's second law in conjunction with analyzing chloride ion profiles following sample submersion. • A novel external perfusion device for accurate assessment of chloride ion leaching in seawater concrete. • Chloride ion leaching increases with soaking time and water-cement ratio significantly impacts leaching, with higher ratios leading to increased leaching. • Supplementary cementitious materials like fly ash and LC2 can both inhibit and promote chloride ion leaching, depending on their content in the mixture. [ABSTRACT FROM AUTHOR]

The corrosion of nuclear containment liners is a serious issue. This study aims to develop a comprehensive understanding of the influence of mill scale on the passivation, depassivation, and corrosion of the specialized steel in simulated concrete pore solutions with varying pH. The formation processes and compositions of passive films and corrosion products were studied utilizing electrochemical measurements and microstructural characterization techniques. The results indicated that the barrier and multichannel effects of the mill scale with local defects negatively affected the passivation and depassivation properties of steel liners, resulting in a passive film of poor quality and premature corrosion initiation. While an increase in pH did not significantly enhance the passivation quality of the as-received steel, it did enhance the critical chloride ion content. In addition, the inhibition mechanism of the mill scale during the continuous corrosion stage of the steel liner was elucidated based on the coupling effects between the mill scale and the rust layer on the steel substrate surface. The results of this study provide a technical reference for the anticorrosion effects of nuclear power plants. [Display omitted] • The intrinsic corrosion-resisting property of the specialty steel for containment liner was explored. • A unified analysis of effects of mill scale on the corrosion of steel liner throughout the whole life period was proposed. • Coupling effects between the mill scale and pH of the solutions were further discussed. • The formation process and compositions of passive films and corrosion products were microscopically explored. [ABSTRACT FROM AUTHOR]

A mesoscopic model is proposed to investigate the combined effects of coarse aggregates (CA) and cracks on mass transport and corrosion of steel bars in concrete under chloride exposure. The accuracy of the model is validated using existing experimental data. Additionally, the corrosion morphology, depth, and quantity throughout the lifespan of the models are calculated and analyzed. The results indicate that both cracks and CA enhance the non-uniformity of corrosion morphology, displaying convexities-concavities and heart-shaped characteristics, although they play a varying role of inhibition or acceleration effects in influencing the corrosion rate, respectively. When it exceeds 0.05 mm, widths of cracks dominate the accelerated corrosion process of initiation and propagation stages, whereas CA controls the final corrosion rate at the overall corrosion stage. Furthermore, a simplified equation is proposed to predict the residual area of steel bars, offering a reference for evaluating the corrosion state of steel bars in cracked concrete. • Establishment of a mesoscopic model considering the coupling effects of volume fraction of aggregate and cracks width. • Predict the mass transportation (chloride ions and oxygen) conditions in concrete and corrosion morphology of steel bars. • Revelation of coupling influence of aggregates' inhibited and cracks' accelerated effect on the corrosion condition of steel bars. • Proposed an equation to predict the residual area of steel bars in concrete with different crack width at any time. [ABSTRACT FROM AUTHOR]

This study investigated the chloride-induced durability deterioration mechanism at the interface of carbon fiber reinforced polymer (CFRP) and steel joints exposure to wet-dry cycling environment, using 27 specimens with varying corrosion levels of steel and aging periods of bonded joints. Characterization including macro and microscale observation, quantification of topographical structure, analysis of surface wettability and adherent residues, were employed to understand the steel surface conditions and their relationship with durability performance under prolonged wet-dry cycles. The results indicated that various steel surface characteristics influenced the interface in both the short and long terms; however, the priority shifted from topography for new steel to cleanliness for corroded steel. As the corrosion level of the steel increased with the aging period, notable declines were observed in the joint's ultimate capacity (∼33.4 %) and its displacement (∼9.94 %) in general responses, along with decreases in maximum slip (∼31.0 %) and shorter plateaus in local responses. This corresponded to an undesirable shift in the triggering failure mode at the ends. Additionally, deterioration mechanism encompassed "foreign attacks" as external factors, marked by corrosion at the bonding edges and inward capillary diffusion of chloride ions, and "domestic unrest" as internal factors, exemplified by the development of those adherent chloride/rust residues, weakening steel-adhesive bonds, and risk of separation. Finally, a time-dependent environmental reduction factor for the capacity model was proposed and verified using collected test data. • Optimizing surface preparation for corroded steels to enhance the bonding behavior of CFRP-steel joints. • Revealing chloride-induced deterioration mechanism, encompassing "foreign attacks" and "domestic unrest". • Developing a time-dependent reduction factor based on the energy release rate. [ABSTRACT FROM AUTHOR]

The incorporation of fly ash (FA) and MgO expansive additive (MEA) is a frequent practice to satisfy the functional prerequisites of temperature control and crack prevention for dam concrete. Nonetheless, the internal environment of concrete dams is comparatively intricate and the expansion of MEA is susceptible to a variety of factors. Consequently, this study systematically delves into the evolution law and influencing mechanism of the durability of FA-blended cement paste modified by MEA, utilizing the rapid chloride ion penetration test, accelerated carbonation test, rapid freeze-thaw cycle test, mercury intrusion porosimetry (MIP), electrochemical impedance spectroscopy (EIS) and thermogravimetry (TG). The findings suggest that by increasing the curing temperature, the joint use of FA and MEA can prevent the decline of durability caused by 10% MEA efficiently and convert the impact of FA on durability into a positive effect. The inward transport path of external chloride ions, CO 2 and water is obviously obstructed by the refinement of pore size and the increase of tortuosity, leading to a reduction of the migration rate. The electrochemical equivalent circuit R s (Q 1 (R ct1 W 1))(Q 2 (R ct2 W 2)) is suitable for analyzing the EIS of FA-blended cement paste modified by MEA, and there was a strong correlation between R s and the resistance to chloride ion penetration. The substantial generation of hydroxides boosts significantly the stockpile of carbonizable substances. Furthermore, compared to Portland cement, it is a cleaner cementitious material, reducing economic costs, carbon emissions, and energy consumption by 8.2%, 29.1%, and 43.9%, respectively. This study can provide effective guidance for the green high-performance design of dam concrete mix proportions. • The increase in curing temperature and the addition of MgO jointly promote the positive effect of FA on durability. • The refinement of pore size and the increase in tortuosity hinder the transport of chloride ions, CO 2 and water. • FA-blended cement paste modified by MEA has higher economic and environmental benefits, fully reflecting sustainability. [ABSTRACT FROM AUTHOR]

This study investigates the synergistic effects of chloride ions, carbonation, and relative humidity on rebar corrosion in mortar, elucidating the complex interactions at the rebar-mortar interface. Findings reveal that chloride ions and carbonation significantly alter the volumetric water content and resistivity of mortar, leading to non-binary corrosion behaviour through area effect, ohmic control, and anode-to-cathode ratio. In chloride-free, non-carbonated mortar, the area effect dominates, whereas the presence of chloride introduces ohmic control and a saturation-dependent anode-to-cathode ratio. In carbonated mortar, a distinctive ohmic control mechanism emerges, governed by local ionic conductivity. This study highlights the critical need to consider these combined effects for accurate prediction and mitigation of rebar corrosion in concrete structures. By advancing the understanding of these mechanisms, the research provides valuable insights for improving the durability of reinforced concrete structures exposed to harsh environmental conditions. • Effects of carbonation and chloride on water retention and resistivity in mortar. • Water affects corrosion by area effect, ohmic control, and varying anode-to-cathode ratio. • Different water saturation-dependent corrosion potential in non-/carbonated mortar. • Ohmic control in chloride-rich carbonated mortar is not governed by bulk resistivity. [ABSTRACT FROM AUTHOR]

Rice husk ash (RHA), an abundant agricultural by-product, has led to significant environmental pollution due to current treatment methods. To achieve resource utilization, the feasibility of RHA recycled concrete subjected to the salt freezing-thawing resistance was assessed, including the macroscopic properties, microstructure and sustainability, and an evolutionary model of salt freeze-thaw damage was established based on the time-dependent hydration reaction of the cement paste. The results indicate that RHA particles effectively retard damage by limiting chloride ion diffusion and preventing salt crystallization, while deteriorating the concrete performance due to reduced hydration products at high RHA replacement ratios. The established salt freeze-thaw damage evolution model has an R2 as high as 0.9817, which indicates that the model fits with high accuracy and can capture the performance variations of different types of RHA recycled concrete under extreme environmental conditions. Additionally, the synergistic preparation of concrete using RHA with a 20 % replacement ratio and recycled coarse aggregate (RCA) with a 50 % replacement ratio reduces the total global warming potential (GWP) by 16.65 %, which means that it has the potential to advance low-carbon sustainable development in the construction industry while meeting the engineering requirements. This research is expected to provide a theoretical reference for applying and promoting biobased low-carbon concrete with RHA in saline-alkali cold areas. • The damage evolution model was established based on the time-dependent hydration reaction. • The salt freeze-thaw damage deterioration mechanism with rice husk ash was proposed. • The sustainability of concrete mixtures was assessed using global warming potential. [ABSTRACT FROM AUTHOR]

The utilization of deep eutectic solvents (DESs) as a novel class of solvents in metal production offers a promising alternative to aqueous solutions due to their biocompatibility and non-aqueous nature. This study investigated the leaching of sphalerite concentrate using a ternary stable DES composed of choline chloride (ChCl), p-toluene sulfonic acid (PTSA), and ethylene glycol (EG) (at a molar ratio of 1:1:1). The effects of time, temperature, and milling time on zinc recovery were examined within specific ranges (20–1440 min, 40–100 °C, and 0–24 h, respectively). The study revealed the significant influence of time and temperature on zinc dissolution efficiency within ChCl:PTSA:EG. Higher temperatures and longer leaching times were found to improve efficiency substantially. The research emphasized the crucial role of milling time, demonstrating that longer durations enhanced zinc efficiency by introducing more defects on the sphalerite surface and reducing particle size. Under optimized conditions, including a temperature of 100 °C, 24 h of ball milling, and 1440 min of leaching, a zinc recovery of 99.7% was achieved. Infrared analysis confirmed the chemical stability of the solvents during the leaching process. The sphalerite leaching process involved the formation of zinc chloride ion complexes and evolution H 2 S gas. An unexpected finding is the presence of lead sulfate in the leach residue, which may be attributed to sulfide oxidation to sulfate species. The Avrami kinetic model provided an excellent fit with the sphalerite dissolution data in ChCl:PTSA:EG DES, indicating that the rate-controlling step was primarily influenced by the diffusion process. R2 values for kinetics fitting data were in the range of 0.87–0.97 for temperature of 40–100 °C. The molecular dynamic (MD) simulation findings indicated robust electrostatic interactions between the metal ions Zn2+ and Fe2+ and the Cl− ions of the ChCl molecules. Additionally, the MD calculations showed that the metal ions formed complexes with some O-S-O atoms within the PTSA molecule. [Display omitted] • Ternary DES (ChCl:PTSA:EG) can be used for sphalerite concentrate leaching. • Zinc dissolution improves with higher temperature and time. • Longer milling boosts efficiency by reducing particle size. • Infrared analysis confirms solvent stability during the leaching process. • MD simulation reveals strong metal-ion interactions with Cl− and O-S-O. [ABSTRACT FROM AUTHOR]

• The Cl− is oxidized on the WO 3 @BiVO 4 surface and converted into chlorine radical. • Boosted H 2 O 2 is generated on the oxidized carbon black cathode. • H 2 O 2 is converted into hydroxyl radicals through the electro-Fenton process. • The chlorine radical and hydroxyl radical enable the synergistic sterilization. A photoelectrocatalytic system has been developed utilizing the WO 3 @BiVO 4 photoanode and the oxidized carbon black (CB) cathode, enabling the synergistic advanced oxidation treatment by combining chlorine radicals and hydroxyl radicals. The WO 3 @BiVO 4 heterojunction is prepared through hydrothermal growth of BiVO 4 onto the surface of WO 3 synaptic structure. The as-prepared WO 3 @BiVO 4 |Pt system demonstrates a remarkable degradation efficiency of organic pollutants with 97.1 % in 30 min under visible light irradiation with a 1.2 V bias, which is 1.24 times higher compared to the WO 3 |Pt system. Furthermore, even when utilizing actual seawater as the electrolyte, the treatment efficacy remains high at 92.8 % within 20 min. The oxidized CB cathode is obtained by calcining commercial CB in the air atmosphere. The WO 3 @BiVO 4 |CB system achieves the degradation efficiency of 85.9 % within 10 min in simulated seawater, utilizing the electro-Fenton process at 0.2 V. The WO 3 @BiVO 4 |CB system effectively removes organic pollutants through the synergistic effect of combining the WO 3 @BiVO 4 photoanode with CB-A cathode. Additionally, impressive degradation efficiency of 97.8 % is achieved in 15 min when using simulated seawater as the electrolyte. The •OH, •Cl, and •Cl 2 − play the key role in the WB|CB-A synergistic system. The combined action of anodic active chlorine radicals and cathodic electro-Fenton process in the WO 3 @BiVO 4 |CB system demonstrates effective microorganism sterilization, resulting in a 92.5 % reduction within 15 min [ABSTRACT FROM AUTHOR]

• PVDF-50 membrane shows highest reported nitrate over chloride selectivity. • Performance PVDF-50 membrane in electrodialysis independent of applied current density. • Nitrate-selectrodialysis (NO 3 -SED) system designed to boost nitrate concentration and simultaneously lower chloride levels. The depletion of natural resources and the escalating environmental concerns associated with pollution necessitate innovative approaches for sustainable resource management. In this study, we investigated the selective separation of nitrate from chloride in electrodialysis (ED) using a recently introduced PVDF-based anion-exchange membrane (PVDF-50) and two commercially available membranes (ACS and AMX from Neosepta). Experimental ED data show that the membrane PVDF-50 presents a higher value of nitrate over chloride selectivity compared with the two commercial membranes, the highest reported in literature. However, recognizing that completely preventing the permeation of chloride ions into the concentrate stream was not feasible, we explored the potential of a system in which anion-exchange membranes presenting different monovalent selectivity were alternated. In this approach, referred to as nitrate-selectrodialysis (NO 3 -SED), the different selectivity of PVDF-50 and AMX membranes was leveraged to demonstrate the possibility of increasing nitrate concentration, while simultaneously reducing chloride levels in a stream. This approach proves highly advantageous in applications where mitigating chloride contamination is a significant concern while recovering nitrate. [ABSTRACT FROM AUTHOR]

Urea abatement has been a prominent challenge for UPW production. This research proposed a productive strategy combining pre-chlorination and VUV/UV processes under acidic conditions to settle this problem. This study first revealed the reaction kinetics between urea and free chlorine in a large pH range from 2.5 to 9.6, where the reaction constant rate varied from 0.06 to 0.46 M−1·s−1. Substitution reaction mediated by Cl 2 was the dominant process at low pH (pH<3). The differences of dominant pathways resulted in the differences in reaction products: The detected concentration of dichloramine at pH 2.5 was twice that at pH 4.5 and 6.5. Further, this study found that pre-chlorination/VUV/UV process could achieve the thorough removal of 2-mg/L urea with chlorination of less than 5 min and VUV/UV irradiation of less than 200 mJ/cm2. Chloride ions, low pH, and higher chlorine dosage were found to be the positive factors to improve urea removal efficiency in pre-chlorination/VUV/UV process. The reaction rate constants between chlorourea with·OH and·Cl were calculated to be 3.62 × 107 and 2.26 × 109 L·mol−1·s−1, respectively.·Cl,·OH and photolysis contributed 60.5 %, 22.9 % and 16.6 % in chlorourea degradation, respectively. Pre-chlorination/VUV/UV achieved a DOC removal efficiency of 78.5 %. And nitrogen in urea was converted into inorganic nitrogenous compounds. Finally, compared with direct VUV/UV/chlorine and VUV/UV/persulfate processes, this process saved more than 70 % of energy in VUV/UV unit. [Display omitted] • Proposed one of most efficient ways to remove urea in UPW production. • Revealed the reaction kinetics of urea chlorination in a large pH range. • Investigated promotive factors of pre-chlorination/VUV/UV for urea removal. • Illustrated the key enhancement mechanisms in urea removal. • Gained a high DOC removal rate with no organic nitrogenous byproducts. [ABSTRACT FROM AUTHOR]

The advent of flexible single-walled carbon nanotube thin-film transistors (SWCNT-TFTs) has transformed electronics, providing significant benefits like low operating voltage, reduced power consumption, cost-effectiveness, and improved signal amplification. This study focuses on leveraging these attributes to develop a novel flexible high-sensitivity and energy-efficient chloride ion sensors based on printed flexible SWCNT-TFTs utilizing polymers-sorted semiconducting SWCNTs (sc-SWCNTs) as the active layers and ion liquids-poly(4-vinylphenol as dielectric layers along with the evaporated deposition of aluminum electrodes and printed silver electrodes as the gate and source-drain electrodes, respectively. The sensors exhibit several operational advantages, including low voltage requirements (≤1 V), rapid response speed (5.32 s), significant signal amplification (Up to 702.6 %), low power consumption (0.31 μJ at 1 mmol chloride ion), good repeatability, high sensitivity for both low and high concentrations of chloride ion (up to 100 mmol/L) and excellent mechanical flexibility (No obvious changes after bending for 10,000 times with a 5 mm radius). The detection mechanism of chloride ions was analyzed using X-ray Photoelectron Spectroscopy (XPS). It was found that chloride ions react with silver nanoparticles (AgNPs) to form silver chloride (AgCl) on printed electrodes, impeding carrier transport and reducing the currents in SWCNT TFTs. Importantly, our sensors' compatibility with smart devices allows for real-time monitoring of chloride ion levels in human sweat, offering significant potential for daily health monitoring. High-sensitivity and energy-efficient chloride ion sensors based on flexible carbon nanotube thin-film transistors for real-time monitoring chloride ions in human sweat. [Display omitted] • Innovative design of high-sensitivity and energy-efficient chloride ion sensors. • Exhibiting rapid response speed and excellent mechanical flexibility. • Compatibility with smart devices for health monitoring applications. • Enabling real-time monitoring of chloride ions in human sweat. [ABSTRACT FROM AUTHOR]

Cu corrosion in aerated NaCl solution containing different bentonite content was investigated using electrochemical impedance spectroscopy and surface analysis techniques. In NaCl solution, Cu corrosion proceeds with CuCl ads formation and its transformation to Cu 2 O. The outer deposit layer consists of Cu 2 O and Cu 2 (OH) 3 Cl. The self-catalyzed comproportionation reaction between Cu and CuCl x (x−2)− produces CuCl x (x−1)−, leading to accelerated Cu corrosion. Bentonite slurry (10–30 wt%) shows supernatant and sedimentation layers. In supernatant layer, Cu corrosion happens with the help of anions dissolved from bentonite minerals. In sedimentation layer, Cu corrosion is hindered due to suppressed cathodic reaction and the self-catalyzed comproportionation reaction. • Cu corrosion was studied in bentonite slurries with supernatant and sedimentation. • Cu corrosion is accelerated by a self-catalyzed comproportionation reaction. • Anions released from bentonite lead to accelerated Cu corrosion in supernatant. • Cu corrosion is hindered in sedimentation layer due to suppressed O 2 diffusion. [ABSTRACT FROM AUTHOR]

In this study, a finely ground nickel sulphide concentrate, consisting mainly of pyrrhotite, pentlandite and chalcopyrite, was leached in shake flask and batch reactor experiments. The objective was to determine the optimal method to recover nickel and cobalt, both hosted in pentlandite, and copper hosted in pentlandite and chalcopyrite respectively. The selected leaching methods tested were sulphuric acid leaching, ferric sulphate leaching and bioleaching. In addition, the effect of chloride ions on the leaching efficiency was evaluated with different concentrations. The results of the chemical leaching experiments showed increase in nickel, cobalt and copper recovery with chloride addition as a result of increased leaching rate for pentlandite and chalcopyrite. The highest yields in the 8-hour reactor experiment (70 % Ni, 66 % Co and Cu 87 %) were obtained in ferric sulphate leaching with chloride concentration of 20 g/L at the temperature of 90 °C. The mineralogical analysis showed that pyrrhotite was dissolved almost completely in all the experiments. Pentlandite and chalcopyrite leaching was clearly improved by the addition of Cl− at similar temperatures. • This research focuses on the development of a hydrometallurgical nickel, cobalt and copper production process. • We have experimentally evaluated three different leaching methods to recover valuable metals from sulfidic concentrate. • Based on batch experiments the most promising method was piloted in reactor experiments reaching high metal recoveries. [ABSTRACT FROM AUTHOR]

[Display omitted] • Template free synthesis of CA-AuNS at room temperature was examined. • Effect of shape directing agents and anions on the AuNS morphology was investigated. • Electrocatalytic activity of NB was studied at GC/CA-AuNS electrode. • Selective and sensitive determination of NB was achieved at GC/CA-AuNS electrode. • Practical application was demonstrated by determining NB in lake water sample. In this article, we established to produce anisotropic, colloidally stable gold nanostructures (AuNS) by rapidly mixing aqueous solutions of gold(III) chloride trihydrate (HAuCl 4) and citric acid (CA) as dual reducing and capping agents at room temperature without the aid of a templating agent. Furthermore, the impact of various anions and shape-directing agents on the morphology and reaction kinetics of citric acid-capped gold nanostructures (CA-AuNS) was investigated. Additionally, the electrocatalytic activity of AuNS towards nitrobenzene (NB) was examined using a CA-AuNS modified glassy carbon (GC) electrode. The rate of reaction for the formation of CA-AuNS increased rapidly with higher concentrations of CA, indicating a strong dependence on the reductant's concentration. This process followed first-order kinetics, suggesting that the reaction rate is directly proportional to the citric acid concentration. Consequently, optimizing CA levels can effectively control the synthesis rate and yield of CA-AuNS. The presence of nitrite ions led to rapid aggregation of gold nanostructures (AuNS) and a quick reaction time. Chloride ions increased the size of the AuNS. As bromide ion concentration increased, the reaction time slowed significantly, resulting in spherical gold nanoparticles. Both acetate ions and polyvinylpyrrolidone (PVP) inhibited the growth of AuNS. High-resolution transmission electron microscopy (HR-TEM) images showed the formation of various shapes, including spherical, hexagonal, pentagonal, and boat-like structures. In the presence of cetyltrimethylammonium bromide (CTAB), both complex formation between CTAB and HAuCl 4 and the formation of spherical gold nanoparticles occurred. Upon addition of silver nitrate (AgNO 3) to the colloidal solution, the color shifted to pale violet, and the morphology transitioned from anisotropic to irregular. However, when ascorbic acid (AA) was utilized, it proved ideal for maintaining the morphology of gold nanostructures (AuNS). The analysis of X-ray diffraction spectroscopy (XRD), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and Fourier transform infrared spectroscopy (FT-IR) further confirmed the synthesized CA-AuNS. The FT-IR spectra of CA before and after the formation of AuNS indicated the participation of carboxylic acid (–COOH) and hydroxyl (–OH) groups in the reduction process of Au3+ metal ions. The GC/CA-AuNS electrode exhibits a larger electroactive surface area due to the coating of AuNS onto the electrode surface, enhancing the electrode's electrical conductivity by providing additional active sites for electron transfer. In addition, the electrocatalytic activity of NB was investigated in this study. The GC/CA-AuNS electrode had better electrocatalytic activity than the unmodified GC electrode. As a result, with a LOD of 28.2 nM (S/N = 3), this electrode was chosen for sensitive NB determination. [ABSTRACT FROM AUTHOR]

Shortly after casting, offshore reinforced concrete structures are exposed to sulfate and chloride ions without undergoing any proper curing procedures, which are crucial for enhancing their strength and durability. Furthermore, there persists a lack of comprehensive understanding concerning the coupled impact of the attack of sulfate and chloride ions on cementitious materials with current existing research still yielding conflicting outcomes. This paper investigates the influence of curing on the chemical interactions between low-carbon cementitious materials (substituting 45 % of cement with industrial by-products like slag, fly ash, and metakaolin to reduce CO 2 emissions) and coupled sulfate and chloride ions. To achieve this, powder samples were obtained from prismatic-shaped specimens of ordinary Portland cement (CEM I) paste, binary, ternary, and quaternary blends. Some solid specimens were ground into powder after 24 hours post-casting while others were powdered after a 90-day curing period. Subsequently, the acquired powders underwent exposure to chloride, sulfate, and sulfate-chloride solutions over a duration of 25 days. Results indicate that curing time does not alter the interplay between sulfate and chloride ions in the cementitious matrix. Sulfate presence accelerates chloride ion ingress, while chloride presence mitigates sulfate attack in both uncured and pre-cured samples. However, the curing process accelerates sulfate attack, proven through excessive ettringite and gypsum formation, high consumption of portlandite and AFm, diminution of sulfate ions concentration in the attacking solution after 5 days of exposure, increase of pH of more than 0.5 units, aspect changes observed through visual inspections, and porosity distribution changes showed by an increase of 10 % of the total porosity in the reference mix. Additionally, curing promotes the formation of Friedel's salt, thereby attenuating chloride ions ingress. [Display omitted] • Chemical interactions of sulfate-chloride attack are highlighted. • The presence of sulfate accelerates the chloride ingress in the materials. • Chloride diffusion mitigates the sulfate attack in the materials. • Curing duration does not affect the sulfate-chloride coupling chemical process. • Raman spectroscopy serves as a quick chemical characterization technique on solutions. [ABSTRACT FROM AUTHOR]

This study explores the effects of glazed hollow beads (GHB) dosage and additional water amount on the capillary negative pressure, mechanical properties, initial resistivity, and electric flux in conditions where recycled aggregate concrete (RAC) is subject to cracking. The chloride ion (Cl-) diffusion coefficient for RAC cured internally was evaluated using the resistivity method, which also looked at the relationship between the diffusion coefficient, GHB dosage, and additional water amount. This analysis advances our understanding of the functional mechanisms of pre-soaked GHB in RAC. The research reveals that incorporating pre-soaked GHB enhances RAC in two primary ways. Firstly, pre-soaked GHB acts as an internal curing agent that stimulates the formation of hydration products, thereby filling internal voids and mitigating micro-crack development. Secondly, it functions as an adsorbent. The differential in relative humidity and internal pressure between the unsaturated GHB and the cement stone matrix promotes the sequestration of corrosive agents in cracked RAC. Additionally, an internal curing impact factor has been introduced, forming the basis of a new model to calculate the Cl- diffusion coefficient that accounts for both GHB dosage and additional water intake. The established quantitative relationships between resistivity, electric flux, and Cl- diffusion coefficient in GHB-treated RAC (GHB-RAC) provide a methodological framework for quickly evaluating the durability of GHB-RAC against Cl- intrusion in practical engineering contexts. • Pre-soaked GHB hinder the permeation of chloride ions in RAC through internal curing and adsorption mechanisms. • A quantitative relationship has been established between the internal curing impact factor and the durability of RAC. • A rapid assessment method has been proposed to evaluate the chloride ion permeability of GHB-RAC. [ABSTRACT FROM AUTHOR]

Previous studies mainly focused on the effects of concrete carbonation on chloride ion penetration due to the resulting reinforcement corrosion. However, it is still being determined what influence sea salt, which is common in coastal areas, has on the carbonation of cement based building materials. Thus, cement mortar samples were immersed in simulated seawater and then submitted to an accelerated carbonation test at a CO 2 concentration of 5 % and a relative humidity of 58 %. For the samples that underwent different carbonation cycles, weight changes and carbonation depth were measured, and the associated mechanisms were demonstrated by combined thermogravimetry and differential thermal analysis (TG-DTA), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP). The results showed that salt crystals do not significantly change the pore size distribution and composition of cement mortar, but effectively influence the carbonation rate. The carbonation rate of the cement mortar sample containing sea salt was 36 mm/year0.5, 36.8 % lower than that of the control sample. Carbonate crystals efficiently occupy the pore volume in the size range of 0.02–0.15 μm and significantly reduce the carbonation rate. The results can provide a research basis for estimating the carbonation rate and measuring the CO 2 uptake of cement-based building materials in coastal regions. • Sea salt deposition on cement mortar can significantly decrease carbonation rate. • Carbonation reduces the pore volume in the range from 0.02 μm to 0.15 μm. • Distinct salts exhibiting varying levels of inhibition of CO 2 uptake. • A synergistic effect between salts led to carbonation rate reduction. [ABSTRACT FROM AUTHOR]