Chloride Concentration Research Articles

Probabilistic prediction model for critical chloride concentration of reinforcement corrosion based on improved Gaussian process regression

Probabilistic prediction model for critical chloride concentration of reinforcement corrosion based on improved Gaussian process regression

Analysis of deliquescent chloride salt by laser-induced breakdown spectroscopy with controlled uniform precipitation

BackgroundThe electrolytic efficiency in magnesium (Mg) production by molten salt electrolysis is mainly affected by the chloride content, which is determined by the metal content in the cooled molten salt. Laser-induced breakdown spectroscopy (LIBS) is a potential element detection method in cooled molten salt element detection. However, the cooled molten chloride salt is easily deliquescent, which greatly affects the LIBS detection results. ResultsTo solve the problem, a liquid-phase precipitation method based on the addition of a dispersant named as controlled uniform precipitation (CUP) method was proposed to pretreat the samples. Compared with the conventional powder compacting method and precipitation method, the CUP obtained the highest spectral stability and detection accuracy. The average relative standard deviation (ARSD) of Mg, Ca, and Na decreased from the 51.80%, 77.04%, and 44.01% to 6.77%, 6.27%, and 29.97%, the determination coefficient of the calibration curve (R2) increased from 0.044, 0.084, and -0.109 to 0.974, 0.954, and 0.802, and the average relative error (ARE) decreased from 58.49%, 52.46%, and 99.78% to 8.58%, 11.28%, and 29.38%, respectively, compared with the powder compacting method. Further investigation showed that the CUP method suppressed the sample deliquescence and the coffee ring effect, leading to the performance improvement of LIBS quantitative detection. SignificanceThe CUP provided an effective method of detecting metal elements for deliquescent samples and showed applied potential for other precipitable elements detection.

Synergistic management of nitrogen contamination in overflow wastewater and algal proliferation in lake receiving wastewater based on electrochemical oxidation process

Urban lake eutrophication, largely driven by overflow wastewater, plays a pivotal role in precipitating algal proliferation due to heightened nitrogen levels in aquatic ecosystem. In addressing this question, this study investigated the chloride-mediated electrochemical oxidation system as a promising solution for controlling nitrogen contamination in overflow wastewater and inhibiting algal proliferation in wastewater-receiving urban lakes, and also evaluated the influence of essential operational parameters on the performance of system. The results indicated that, under the environmental conditions set by this experiment, the removal efficiency ranges of ammonia nitrogen and total nitrogen were 14.91 % - 100 % and 13.98 % - 99.62 %, respectively; meanwhile, the maximum algae inhibition rate could reach 100 % at a capacity ratio of 0.01. Response Surface Method analysis highlighted current density as the preeminent factor in nitrogen removal and algae inhibition, surpassing the influence of initial chloride ion and nitrogen concentrations within the system. Notably, an excessive current density could inadvertently lead to the nitrate nitrogen accumulation (up to 29 %), thereby diminishing the total nitrogen removal efficiency, particularly in low nitrogen-concentrated overflow wastewater scenarios. With respect to algae inhibition, a direct correlation was identified between higher residual total chlorine concentrations in the receiving lake and increased algae inhibition rates (R = 0.90, P < 0.05), and the residual total chlorine was found to exert pronounced inhibition on cyanobacteria compared to other algal forms. However, caution was advised regarding potential algal growth stimulation if the initial received total chlorine concentration in the urban lake receiving wastewater below 0.5 mg/L. These findings not only affirm the feasibility of this synergistic approach but also elucidate critical aspects for process optimization and control.

Anions exacerbate microbial corrosion of X80 pipeline steel induced by sulfate-reducing bacteria in the sea mud environment

Sulfate-reducing bacteria (SRB) present in sea mud pose a challenge to the safe operation of subsea pipelines. Chlorides and sulfates in sea mud promote the microbial corrosion of subsea pipelines by SRB. This study investigates the effects of sulfate and chloride on the microbial corrosion of X80 pipeline steel in the sea mud environment. The results indicate that sulfate serves as an electron acceptor, promoting the growth of SRB, while chloride regulates the osmotic pressure of SRB cells, affecting their bioactivity. SRB exhibit more aggressive corrosion behavior in sea mud with high concentrations of both chloride and sulfate.

“Copper-loaded microplastics unleash endoplasmic reticulum stress-driven liver apoptosis in fish Channa punctatus”

The extensive use of plastics has led to significant microplastic pollution, posing threats to environmental and human health. Concerns are growing about the toxicity of microplastics (MPs) and their ability to adsorb contaminants like Copper (Cu2+). Therefore, this study investigated the effects of environmentally realistic concentrations of Polyvinyl Chloride (PVC)-MPs and Copper, both individually and together, with a particular focus on triggering Endoplasmic reticulum (ER) stress-driven apoptosis in the liver of Channa punctatus. Well-habituated fish were organized into four groups: Group I (Control), Group II (0.5 mg/L PVC-MPs), Group III (0.85 mg/L Copper), and Group IV (0.5 mg/L PVC-MPs + 0.85 mg/L Copper). The treatment period was 15, 30, 45 and 60 days. Various liver parameters were assessed according to standard protocols to understand the repercussions of intoxication. A significant (p < 0.05) increment in Reactive Oxygen Species (ROS) pointed to a substantial rise in oxidative stress. Enzymatic antioxidants like superoxide dismutase (SOD) and catalase (CAT) showed significantly (p < 0.05) elevated extents while reduced glutathione (GSH) levels significantly (p < 0.05) dropped in a duration-dependent pattern. Additionally, lipid peroxidation (LPO) activities surged significantly (p < 0.05), and notable hepato-structural disruptions were observed. The evidence of liver damage was further verified by a significant (p < 0.05) rise in concentrations of hepatic biomarkers viz. Serum Glutamic Oxaloacetic Transaminase (SGOT), Serum Glutamic Pyruvic Transaminase (SGPT), and Alkaline phosphatase (ALP). Moreover, ER-stress was validated through the increased intracellular calcium levels along with the heightened expression of grp78, chop, atf4, perk, eIF2α, and gadd34 in exposed groups. This intricate cascade subsequently elicited the activation of bax, caspase-3, caspase-9, and apaf-1, while modulation of bcl-2, thereby driving hepatocyte-apoptosis via ER-stress response in C. punctatus, a widely consumed food-fish. Our findings underscore the toxic threats of Copper-laden PVC-MPs to aquatic life and potentially the broader ecosystem.

High cadmium exposure impairs adult hippocampal neurogenesis via disruption of store-operated calcium entry

Cadmium (Cd) is a neurotoxicant that gradually accumulates in the human body with age. High Cd burden is correlated with adult hippocampal neurogenesis (AHN) and memory deficits in mammals. However, little knowledge is known about the mechanism by which Cd exposure impairs neurogenesis and cognition. Here, we investigated the roles of store-operated calcium entry (SOCE)-mediated calcium dyshomeostasis in Cd-induced AHN and memory deficits as well as therapeutic potential for the prevention of Cd-induced neurotoxicity. To achieve this goal, 8 weeks-old C57BL/6 J mice were subjected to different concentrations of cadmium chloride (0, 5, 10, 20 ppm) in drinking water for 8 weeks, we then examined the AHN, calcium homeostasis, SOCE channel and memory in Cd-exposed mice by using immunohistochemistry, calcium imaging, Y-maze and fear conditioning test. Our results indicated that chronic Cd exposure markedly increased Cd levels in serum and cerebrospinal fluid by almost 10-fold, and inhibited the proliferation and differentiation of hippocampal adult neural stem cells in a dose-dependent manner. Additionally, Cd exposure impaired the maturation of hippocampal neural stem cells without inducing gliosis. Transcriptome analysis revealed that Cd exposure inhibited the proliferation of neuroblastoma via alteration of calcium signaling pathway, and attenuated SOCE channels played a pivotal role in mediating Cd-induced cytoplasmic calcium overload and depletion of endoplasmic reticulum calcium stores. Activation of SOCE by hyperforin, a natural derivative from medicinal plant, restored intracellular calcium homeostasis and improved AHN and memory in Cd-exposed mice. Together, this study provided novel insights into the mechanism that Cd exposure impaired AHN and memory by prompting neuronal SOCE-mediated calcium dyshomeostasis, and offered a new therapeutic approach for prevention of Cd-induced neurotoxicity.

Volume therapy: which preparation for which situation?

The most commonly used fluids for volume therapy are crystalloids and colloids. Crystalloids comprise 0.9% sodium chloride and balanced crystalloids (BC). Colloids can be divided into artificial colloids and human albumin (anatural colloid). Large studies show advantages for BC over 0.9% NaCl with respect to renal endpoints, probably due to the unphysiologically high chloride content of 0.9% NaCl. However, other studies, such as the BaSICS and PLUS trials, showed no significant differences in mortality in aheterogeneous population. Despite this, meta-analyses suggest advantages for BC. Therefore, BC should be preferred, especially in patients at increased risk of acute kidney injury, with acidemia and/or hyperchloremia. Except for specific indications (e.g., in patients with cirrhosis, sepsis resuscitation after initial volume therapy with BC), albumin should not be used. There is clear evidence of harm from hydroxyethyl starch in intensive care patients.

Anesthetic sampling and the tissue regeneration potential of oysters: A study with Crassostrea hongkongensis

The use of an appropriate amount of anesthetic can prevent the sacrifice of oysters during experimental sampling or seedling rearing. In this study, we assessed the effects of air exposure and three concentrations of magnesium chloride (10, 40, and 70 g L–1) on the anesthetic efficiency for Crassostrea hongkongensis. We examined the recuperative capacity of the oysters post-tissue sampling. The results indicated that 36 h of air exposure could significantly enhance the anesthetic efficiency of C. hongkongensis while ensuring the oysters’ survival. A 40 g L–1 solution of magnesium chloride had the optimal anesthetic effect on C. hongkongensis across all oyster sizes. In addition, smaller oysters (119.10 g) had a higher relaxation rate than larger oysters (191.00 g). The oysters anesthetized with 40 g L–1 magnesium chloride also demonstrated the best recovery. No deaths were observed among the non-anesthetized oysters, anesthetized-recovered oysters, or non-recovered oysters during a seven-day post-farming period. In terms of live sampling, the control group (100 %), gonad group (100 %), mantle group (98.67 %), gill group (89.33 %), and adductor muscle group (97.33 %) all showed high survival rates after anesthesia. Observation of tissue growth post-sampling revealed the presence of focal green areas in tissues between days 7 and 14. By day 30, the adductor muscle and mantle tissues had fully healed, and the regrown tissue in the gills had approached its original length. A 40 g L–1 magnesium chloride solution had no significant effects on gametes in terms of fertilization rate, growth rate, and attachment rate. The present findings indicated that C. hongkongensis could be effectively anesthetized using a 40 g L–1 magnesium chloride solution following 36 h of aerial exposure. Post-anesthesia tissue and gamete sampling did not result in significant mortality, and the tissues had fully recovered within 30 days post-sampling. The anesthesia did not have any adverse effects on the progeny.

Theoretical Study of the Halogen Concentration Effect on the 1,3-Butadiene Polymerization Catalyzed by the Neodymium-Based Ziegler–Natta System

In this work, an attempt is made to theoretically substantiate the experimentally known facts of the influence of halogen concentration on the catalytic properties of the neodymium-based Ziegler–Natta system. Based on the structural and thermochemical data obtained using modern methods of quantum chemistry, the process of the 1,3-butadiene cis-1,4-polymerization under the model active centers of the neodymium Ziegler–Natta catalysts with different contents of chloride ions was studied. Results are presented that explain the increase in the cis-stereospecificity and activity of the polymerization system with an increase in the content of the chloride ions in the neodymium catalytic system. Reasons were established for the decrease in the concentration of active centers relative to the introduced Nd(III) with an excess of chloride ions and the occurrence of the anti-syn isomerization as a source of the formation of the trans-1,4-structures in the cis-1,4-polybutadiene.

Agricultural Contribution of Chloride to a Saturated Riparian Buffer System: A Case Study in Central Illinois

ABSTRACT Increases in chloride concentrations in surface water and groundwater from anthropogenic sources is a growing concern throughout the world. In the midwestern United States, the agriculture contribution of chloride may elevate concentrations in surface and groundwater systems. A saturated riparian buffer (SRB), installed to reduce nutrient input into an adjacent stream, and the groundwater water upgradient were investigated to identify sources of chloride and to quantify the agricultural contribution. During a 7-year period, over 2,200 water samples collected from 35 wells, a diversion box, and a stream were analyzed for major anions. Additionally, the waters from four quarterly (seasonal) samplings (n = 155) during the seventh year were analyzed for cations. A cumulative probability curve identified three populations of chloride: (1) upgradient shallow groundwater; (2) diversion box (waters drained from an agricultural field), downgradient shallow groundwater (representing the SRB), diamicton groundwater (waters collected deeper from within the unweathered parent material); and (3) stream water. A background chloride concentration was established at 3.9 mg/L. Elevated concentrations above the background level coupled with principal component analysis suggest agricultural contribution from the diverted tile-drainage waters was a source of chloride. In winter and spring, chloride concentrations were highest in the diversion box, while up-gradient wells were the lowest. Waters downgradient of the diversion tiles had chloride concentrations lower than the tile but higher than the upgradient waters due to mixing of the diverted tile water and the upgradient groundwater. For the specific site, agriculture contributes chloride, but at concentrations below the chronic threshold of 230 mg/L.

Diffusion coefficients of Al&lt;sub&gt;2&lt;/sub&gt;Cl&lt;sub&gt;7&lt;/sub&gt;&lt;sup&gt;–&lt;/sup&gt; in low temperature chloroaluminate melt based on triethylamine hydrochloride

With the growing demand for renewable energy sources, much of the research in the battery industry is focused on creating safe and high-capacity energy storage systems that can handle high current loads using inexpensive and readily available materials. The aluminum-ion batteries (AIB) are considered as one of the most promising systems. Such materials as aluminum metal, carbon materials and chloroaluminate ionic liquids are used as anode, cathode and electrolyte, respectively. A low-temperature chloroaluminate melt based on triethylamine hydrochloride (Et3NHCl) is promising and inexpensive electrolytes for AIBs. This melt has the ability to reversibly precipitate/dissolve aluminum metal due to the presence of the Al2Cl7– ion in it. However, the diffusion of Al2Cl7– ions in the Et3NHCl–AlCl3 system has not been studied previously. In the presented work, the concentration dependence of the diffusion coefficients of the Al2Cl7– anion was studied using chronopotentiometry in the concentration range N = 1.3–1.95 (where N is the molar ratio of aluminum chloride to organic salt). It was shown that diffusion coefficients increase with aluminum chloride content growth in the studied melt: from 1.71·10–7 (N = 1.3) to 4.50·10–7 cm2·s–1 (N = 1.95). This behavior can be caused by the viscosity decrease of the melts with Al2Cl7– concentration growth. Based on the obtained results it can be concluded that Et3NHCl–AlCl3 with N = 1.95 is the most suitable electrolyte for AIB. Moreover, it was established that the electrochemical reduction of the Al2Cl7– on the surface of the aluminum electrode is complicated by the nucleation process, which has the lowest overvoltage at N = 1.95.

Investigation of submarine groundwater discharge into the Baltic Sea through varved glacial clays

Submarine groundwater discharge (SGD) is an important process responsible for transporting terrestrial dissolved chemical substances into the coastal ocean, thereby impacting the marine ecosystem. Despites its significance, there are few studies addressing SGD in the northern Baltic Sea. Here we investigate the potential occurrence of SGD in an area characterized by seafloor terraces formed in varved glacial clay located around Fifång Island, Southern Stockholm Archipelago. We analyzed 222Rn activity and porewater geochemistry in both marine and terrestrial sediment cores retrieved from Fifång Island and its surrounding offshore areas. Results from 222Rn mass-balance calculations, water isotopes, salinity, chloride concentration, and dating (including 14C and helium-tritium dating) indicate that modern groundwater flows through varved glacial clay layers and fractured rocks on Fifång Island and discharges into Fifång Bay. Additionally, the offshore cores reveal a saline groundwater source that, dating of the dissolved inorganic carbon, appears systematically younger than the hosting clay varves dated using the Swedish clay varve chronology. Acoustic blanking in our acquired sub-bottom profiles may be related to this fluid migration. The occurrence of this saline groundwater seems to be independent from the distance to the submarine terraces. Collectively, our study confirms the occurrence of submarine groundwater in the varved glacial clay close to Fifång Island and further offshore. Our findings help establish the significance of submarine groundwater discharge in influencing the past and present coastal environment in the Baltic Sea region.

Standardization of Protocol for Production of Synthetic Seed of Brahmi (Bacopa monnieri) and Assessment of their Longevity under Differential Storage Condition

Brahmi [Bacopa monnieri (L) Pennel] is an important medicinal small succulent, medicinal herb belongs to the family ‘Scrophulariaceae’ which is commonly known as Jala Brahmi or Nira-Brahmi. National Medicinal Plants Board (NMPB), estimated an annual demand of Bacopa in 2004-2005 was 6621.8 tonnes, with a 7% annual growth rate. Micropropagation techniques and production of synthetic seeds can be a breakthrough to overcome the low availability of Brahmi propagating materials. So, the present study was conducted to standardize the protocol for preparation of synthetic seeds of Brahmi using nodal segment. The experiment was conducted with five treatments by using combinations of different concentrations of sodium alginate and calcium chloride and preparing two types of synthetic seeds (single layer and double layer). Further the longevity of both single layer and double layered synthetic seeds was studied under two different storage temperatures at 25°C (ambient condition) and 4°C (refrigerator) up to 40 days by inoculating them in two different types of media. The result showed no significant effect of concentrations of gelling agent and complexing agent on the germination percentage of synthetic seeds. The number of shoots per synthetic seed varied from 22.00 to 29.35 with 100% germination and maximum shoots/synthetic seed and shoot length was obtained by using T5 (single layered with MS media, 3% sodium alginate and 2.5% calcium chloride). Maximum number of days of storage can be observed in the single layer synthetic seeds when stored at 4°C along with media followed by double layer synthetic seeds when stored at 4°C along with media. However, seeds stored on vermiculite got dried up in the initial days of storage. Germination was found to be higher in seeds stored at 4°C when compared to seeds stored at 25°C. The study as a whole elucidated the opportunity for the use of synthetic seed as an alternative to traditional propagation system for Brahmi.

The combined leaching of copper, gold and uranium in chloride solutions. II. Concentrate leach tests

This study of the simultaneous leaching of copper, gold and uranium from a flotation concentrate is aimed at establishing the conditions that could be applied in a possible heap leach process that would recover all three metals (plus silver, if present) in a single step. The results obtained in this study confirm the results obtained in Part I (Nicol et al., 2024) that enhanced rates for leaching of chalcopyrite from flotation concentrates from two different sources can be obtained in acidic chloride solutions in the presence of chlorate ions. The measurements of the solution potentials during leaching with chlorate are similar to those obtained previously and confirm that chlorine generated by the chlorate-chloride reaction is the active oxidant.Uranium is dissolved even in the absence of chlorate by iron(III) as the oxidant. The latter is re-generated by reaction of iron(II) with chlorate. The dissolution of gold requires higher potentials, and it is only leached when the potential approaches 1.0 V in concentrated chloride solutions. At low chloride concentrations (1 M), gold is not dissolved because of apparent passivation.An electrochemical study of the behaviour of gold in chloride solutions in the presence of sulfide ions has shown that the passivation is probably the result of the formation of a layer of Au2S on the gold surface at low potentials before the addition of chlorate to the leach solutions i.e., before the generation of sufficient chlorine concentrations. At potentials above about 0.95 V Au2S is unstable being oxidised to AuCl2− and elemental sulfur thereby eliminating passivation.

Lubiprostone Improves Distal Segment-Specific Colonic Contractions through TRPC4 Activation Stimulated by EP3 Prostanoid Receptor

Background: Prokinetic agents are effective in increasing gastrointestinal (GI) contractility and alleviating constipation, often caused by slow intestinal motility. Lubiprostone (LUB), known for activating CLC-2 chloride channels, increases the chloride ion concentration in the GI tract, supporting water retention and stool movement. Despite its therapeutic efficacy, the exact mechanisms underlying its pharmacological action are poorly understood. Here, we investigated whether LUB activates the canonical transient receptor potential cation channel type 4 (TRPC4) through stimulation with E-type prostaglandin receptor (EP) type 3. Methods: Using isotonic tension recordings on mouse colon strips, we examined LUB-induced contractility in both proximal and distal colon segments. Quantitative real-time polymerase chain reaction (qRT-PCR) was conducted to determine mRNA levels of EP1-4 receptor subtypes in distal colonic muscular strips and isolated myocytes. The effects of a TRPC4 blocker and EP3 antagonist on LUB-stimulated contractions were also evaluated. Results: LUB showed significant contraction in the distal segment compared to the proximal segment. EP3 receptor mRNA levels were highly expressed in the distal colon tissue, which correlated with the observed enhanced contraction. Furthermore, LUB-induced spontaneous contractions in distal colon muscles were reduced by a TRPC4 blocker or EP3 antagonist, indicating that LUB-stimulated EP3 receptor activation may lead to TRPC4 activation and increased intracellular calcium in colonic smooth muscle. Conclusions: These findings suggest that LUB improves mass movement through indirect activation of the TRPC4 channel in the distal colon. The segment-specific action of prokinetic agents like LUB provides compelling evidence for a personalized approach to symptom management, supporting the defecation reflex.

Efficient removal of ammonia from aqueous solution using coal-based carbon membrane via electrochemical oxidation in the present of chloride ion

To tackle the escalating issue of ammonia nitrogen water pollution, developing efficient removal technologies holds paramount significance. In this work, an electrochemical membrane reactor (EMR) was constructed for the decontamination of ammonia nitrogen wastewater using the coal-based carbon membrane (CCM) as the flow-through anode. The removal efficiency and degradation mechanism of ammonia nitrogen by EMR during the treatment were investigated. It was found that, under applied voltage and in the presence of chloride ions, the CCM exhibited excellent chlorine evolution performance, and as a result, the EMR had excellent ammonia nitrogen removal efficiency. The removal of ammonia nitrogen by the flow-through EMR was following the pseudo-first-order kinetics. Analysis revealed that various operating parameters, including applied voltage, chloride ion concentration, flow rate, pH value, and initial ammonia concentration, all significantly influenced the ammonia nitrogen treatment performance of EMR. At optimal operation conditions (feed concentration of 30 mg/L, applied voltage of 2.8 V, NaCl concentration of 0.1 mol/L and flow rate of 2 ml/min), the EMR achieved a removal rate of 100 % for ammonia nitrogen with a low energy consumption (EC) of 0.0380 kW•h/g-NH4-N. The degradation mechanism analysis revealed that the primary means of ammonia removal relied on indirect oxidation mediated by OCl·, which was generated by the oxidation of Cl- on the surface of CCM within the solution under the influence of the electric field. Furthermore, the EMR demonstrated good applicability across various water matrices. In conclusion, the EMR holds considerable potential for the decontamination of ammonia nitrogen-containing wastewater.

Acupuncture improves neuroendocrine defects in a preclinical rat model of reproductive aging

AimsClinical data supports electroacupuncture (EA) as an effective treatment for female reproductive disorders especially gonadotropin abnormalities. This study aims to detect the mechanism of EA that improves the neuroendocrine defects particularly the luteinizing hormone (LH) surge failure in early reproductive aging females. Materials and methodsMiddle-aged ovariectomized rats primed with hormone were treated by EA at acupoints CV4 and SP6 and undergone LH assay. Morphological experiments detected the activation of Kiss1 cells in the anteroventral periventricular nucleus (AVPV). Using targeted liquid chromatography with tandem mass spectrometry (LC-MS/MS) and RNA-sequencing, we determined the concentrations of neurotransmitter metabolites and transcriptomics in AVPV. Key findingsEA significantly increased c-Fos and c-Fos-positive Kiss1 cells in the middle-aged AVPV as well as the total and peak LH release. Targeted LC-MS/MS and RNA-sequencing of AVPV identified differential neurotransmitters in the middle-aged females including Acetylcholine chloride, 5-Hydroxyindole-3-aceticacid, Kynurenine, Histamine, L-Histidine and L-Glycine, while EA decreased the concentration of Acetylcholine chloride. Totally 1255 differentially expressed genes modulated by EA were strongly implicated in neurotransmitter transport and KEGG pathways involved neuroactive ligand-receptor interaction, glutamatergic and gamma-aminobutyric acid-mediated synapse. Specifically, the mRNAs associated with the LH surge such as hormone receptor Pgr, adrenoceptor Adra1a, neurotransmitter transporters Slc17a6 and Slc32a1, glutamate decarboxylase Gad2 and Kiss1 were markedly altered by EA. SignificanceThese findings showed that the age-related reduction of LH surge occurred via differential neurotransmitter metabolisms and altered transcriptions in AVPV, which proposed EA-based therapy for improving responsiveness of the hypothalamus to hormone in women with advanced age.

Chemically recyclable polyvinyl chloride-like plastics

Polyvinyl chloride (PVC) is the world’s third-most widely manufactured thermoplastic, but has the lowest recycling rate. The development of PVC-like plastics that can be depolymerized back to monomer contributes to a circular plastic economy, but has not been accessed. Here, we develop a series of chemically recyclable plastics from the reversible copolymerization of cyclic anhydride with chloral. The copolymerization is highly efficient through the anionic or cationic mechanism under mild conditions, yielding polyesters with tunable structure and properties from multiple commercial monomers. Notably, these polyesters manifest mechanical properties comparable to PVC and polystyrene. Meanwhile, such polyesters are flame-retardant like PVC due to high chloride content. Of significance, these polyesters can be depolymerized back to starting monomers at high temperatures owing to the reversibility of the copolymerization, leading to a circular economy. Overall, the readily available monomers, simple synthesis, advantageous performance, and practical recyclability make the polymers promising for applications.

Experimental Investigation of Chloride Ion Monitoring in Concrete Considering the Coupling Effect of Temperature and Humidity

Ag/AgCl electrodes have acquired significant research attention due to their crucial role in the electrochemical monitoring of chloride ion concentration. However, the electrode potential is susceptible to changes in temperature and humidity, and comprehensive investigations regarding the influence of moisture are lacking. Existing studies on Ag/AgCl electrodes have been qualitative, primarily focusing on analyzing the trend of electrode potential to detect variations in Cl- concentration. This study proposes an experimental method that enables precise control of temperature and humidity within concrete. The effects of temperature and humidity coupling on Ag/AgCl electrode potential in a concrete environment and a fundamental model were established correlating Ag/AgCl electrode potential with temperature, humidity, and chloride ion concentration, thereby enhancing the sensing accuracy. The developed model corrected errors from temperature and humidity coupling effects on the Ag/AgCl electrode potential. A quantitative investigation on using Ag/AgCl electrodes for monitoring Cl- concentration was conducted, facilitating their application in engineering and the development of non-destructive monitoring systems for chloride ions in concrete structures.

The hygric properties of cement mortar with salt spray deposition

Many buildings along the coast are exposed to the salt spray climate, but the hygric behavior of porous building materials under the influence of salt crystallization are unclear. In this study, an accelerated salt spray test was conducted on cement mortar. For samples with different salt spray cycles, chloride ion content was measured and saturated moisture content (wsat), open porosity (po) and apparent density (ρb) were obtained by a vacuum saturation test, while capillary absorption coefficient (Acap) and capillary moisture content (wcap) were determined from capillary absorption tests using innovative methods. Additionally, the pore characteristics and micromorphology of the samples were examined and analyzed using a mercury intrusion porosimeter (MIP) and a scanning electron microscope (SEM). The results indicate that a large amount of deposited salt crystals mainly clogs pores with a diameter of 0.02 to 0.12 μm, resulting in a 18.7 % decrease in po as well as a 30 % decrease in Acap and a 17.4 % decrease in wcap subjected to 35 salt spray cycles. This finding supports a deeper understanding of fluid moisture absorption and transfer in building envelope materials in coastal areas.