Low Chloride Research Articles

Displacement of extracellular chloride by immobile anionic constituents of the brain's extracellular matrix

AbstractGABA is the primary inhibitory neurotransmitter. Membrane currents evoked by GABAA receptor activation have uniquely small driving forces: their reversal potential (EGABA) is very close to the resting membrane potential. As a consequence, GABAA currents can flow in either direction, depending on both the membrane potential and the local intra and extracellular concentrations of the primary permeant ion, chloride (Cl). Local cytoplasmic Cl concentrations vary widely because of displacement of mobile Cl ions by relatively immobile anions. Here, we use new reporters of extracellular chloride (Cl−o) to demonstrate that Cl is displaced in the extracellular space by high and spatially heterogenous concentrations of immobile anions including sulfated glycosaminoglycans (sGAGs). Cl−o varies widely, and the mean Cl−o is only half the canonical concentration (i.e. the Cl concentration in the cerebrospinal fluid). These unexpectedly low and heterogenous Cl−o domains provide a mechanism to link the varied but highly stable distribution of sGAGs and other immobile anions in the brain's extracellular space to neuronal signal processing via the effects on the amplitude and direction of GABAA transmembrane Cl currents. imageKey points Extracellular chloride concentrations in the brain were measured using a new chloride‐sensitive organic fluorophore and two‐photon fluorescence lifetime imaging. In vivo, the extracellular chloride concentration was spatially heterogenous and only half of the cerebrospinal fluid chloride concentration Stable displacement of extracellular chloride by immobile extracellular anions was responsible for the low extracellular chloride concentration The changes in extracellular chloride were of sufficient magnitude to alter the conductance and reversal potential of GABAA chloride currents The stability of the extracellular matrix, the impact of the component immobile anions, including sulfated glycosaminoglycans on extracellular chloride concentrations, and the consequent effect on GABAA signalling suggests a previously unappreciated mechanism for modulating GABAA signalling.

Influencing Factors on the Wet Impregnation of Additive‐Manufactured Catalyst Support Structures

AbstractThe wet impregnation of additive manufactured aluminum oxide cylinders with platinum is investigated. The influence of five parameters on the penetration depth and the platinum loading is evaluated. A smaller penetration depth is obtained by increasing pH, sodium chloride concentration in the impregnation solution, decreasing impregnation solution volume, heating rate during subsequent calcination, and no vacuum during prewetting before the impregnation. A pH range of 2 to 4, a low chloride concentration, a small liquid volume, and no vacuum drawing lead to high platinum uptake. This investigation is crucial in understanding and optimizing the wet impregnation process, providing practical guidance for future research with more complex structures.

Activation of Wnt/β-catenin signaling to increase B lymphoma Moloney murine leukemia virus insertion region 1 by lithium chloride attenuates the toxicity of cisplatin in the HEI-OC1 auditory cells

Cisplatin is widely used in anti-tumor therapy, but the ototoxicity caused by high-dose cisplatin often limits its efficacy, and the specific mechanism of cisplatin-induced cochlear damage is still not perfect. The Wnt/β-catenin signaling pathway is closely related to aging, embryonic development, and apoptosis. Meanwhile, B lymphoma Moloney murine leukemia virus insertion region 1 (BMI1) plays a certain role in the evolution and development of the inner ear and the occurrence and development of inner ear-related diseases. Our study intends to explore the role and specific mechanism of the Wnt/β-catenin signaling pathway and BMI1 in improving cisplatin ototoxicity. The appropriate experimental concentrations for each drug were selected by CCK-8 cell proliferation assay and Western Blot to detect apoptosis. The lentivirus transfection of HEI-OC1 cochlear hair cells was used to overexpress BMI1. Western Blot, qPCR, and immunofluorescence detected the activation of each component of BMI1 and Wnt/β-catenin signaling pathway in each experimental model. Wnt/β-catenin signaling pathway and BMI1 are jointly involved in cisplatin-induced cell injury. Low lithium chloride (LiCl) concentrations activated the Wnt/β-catenin pathway, increased BMI1 expression, and reduced cisplatin-induced hair cell injury. In contrast, overexpression of BMI1 inhibited the Wnt/β-catenin pathway and reduced hair cell injury. Meanwhile, the increased cisplatin-induced damage to hair cells by inhibiting BMI1 could not be rescued by LiCl. In conclusion, LiCl can ameliorate cisplatin ototoxicity by elevating BMI1 expression through activation of the Wnt/β-catenin pathway. Overexpression of BMI1 inhibits the Wnt/β-catenin pathway and reduces cisplatin-induced hair cell damage.

Investigation of Scaling and Materials' Performance in Simulated Geothermal Brine.

Geothermal energy generation faces challenges in efficiency, partly due to restrictions on reinjection temperatures caused by scaling issues. Therefore, developing strategies to prevent scaling is critical. This study aims to simulate the scaling tendencies and corrosion effects of geothermal fluids on various construction materials used in scaling reactor/retention tank systems. A range of materials, including carbon steel, austenitic stainless steel, duplex stainless steel, two proprietary two-part epoxy coatings, and thermally sprayed aluminium (TSA), were tested in a simulated geothermal brine. Experiments were conducted in a laboratory vessel designed to replicate the wall shear stress conditions expected in a scaling reactor. The tests revealed varying scaling tendencies among the materials, with minimal corrosion observed. The dominant scale formed was calcium carbonate, consistent with geochemical modelling. The findings suggest that despite the high operating temperatures, the risk of corrosion remains low due to the brine's low chloride content, while the wettability of materials after immersion may serve as a useful indicator for selecting those that promote scaling.

Structural and Solution Speciation Studies on fac-Tricarbonylrhenium(I) Complexes of 2,2'-Bipyridine Analogues.

In this study, we report the synthesis and characterization of 12 novel rhenium(I) complexes with the general formula fac-[Re(CO)3(NN)X]n+ where (NN) is a 2,2'-bipyridine analogue ligand, X = Cl-, Br-, or H2O, and n = 0 or 1, focusing on their speciation in an aqueous solution. The prepared organorhenium complexes are stable in a wide pH range in an aqueous solution, and no release of the bidentate ligands or the carbonyl ligands was observed. The stability of the complexes in various biologically relevant matrices (cell culture medium and real blood serum) was also demonstrated. However, the simultaneous substitution of the halido ligand by water and slow hydrolysis of the ester bonds in the ligands were observed, affecting both the solubility and the lipophilicity of the compounds. The aqua complexes became more lipophilic in the presence of chloride ions, while the hydrophilicity increased significantly with time due to the hydrolysis of the ester bonds, which probably contributed to their weak pharmacological activity. The results also showed kinetically hindered aqueous solvation of the halido complexes and low chloride ion affinity of the aqua complexes. The deprotonation of the coordinated aqua ligand in the complexes occurs in the pH = 7-10 range, leading to significant formation (18-30%) of hydroxido species at pH = 7.4. The halido complexes showed somewhat higher cytotoxicity (IC50 = 60-99 μM) on human colon adenocarcinoma cancer cells (Colo205 and Colo320) than the corresponding aqua complexes (IC50 > 100 μM). In all cases, no antibacterial effect was observed (MIC > 100 μM), but some of the complexes showed moderate antiviral activity (IC50 ∼ 50 μM) on Herpes simplex virus 2.

Metabolic Alkalemia in Hypercalciuria Stone Formers: Does It Matter?

Introduction: The literature lacks whether metabolic alkalemia occurs in outpatients with hypercalciuric nephrolithiasis. Thus, we aim to investigate it because these patients are often treated with thiazides to reduce urinary calcium excretion. However, thiazides induce chloride losses due to the inhibition of Na-Cl cotransporter expressed in the renal distal tubule cells. Besides thiazide prescription, many of these patients are also supplemented with potassium citrate, which is an addition of alkali source in their bodies. Methods: We collected clinical, demographic characteristics, and laboratory data from electronic medical charts of outpatients with calcium kidney stones followed in our institution from January 2013 to July 2021. We diagnosed those cases as metabolic alkalemia, in which the venous blood gas tests showed pH ≥7.46 and bicarbonate concentration >26 mEq/L. Then, we applied statistical analysis to compare distinct categories between patients with and without metabolic alkalemia. Results: We diagnosed metabolic alkalemia in 4.3% of hypercalciuric nephrolithiasis outpatients, and we verified that thiazides had been used in all of them except in one case. Furthermore, we observed that the amount of thiazide taken daily was higher in patients with metabolic alkalemia than in those without this imbalance. Additionally, hypokalemia was present in 37% of patients who developed metabolic alkalemia. We also found lower chloride, magnesium and ionic calcium serum concentrations in patients with metabolic alkalemia than in those without an acid-base disequilibrium. Conclusion: Despite the low prevalence of metabolic alkalemia in hypercalciuric kidney stone formers, it is important to monitor these patients due to the high incidence of hypokalemia and the potential presence of other electrolyte disorders.

Passivation and depassivation of reinforcement steel in alkali-activated materials—A review

This paper reviews the formation and breakdown of passive film on the surface of reinforcement steel in alkali-activated materials (AAMs) considering the characteristics of reaction product and pore solution chemistry. The literature review shows that the pore solution of AAMs has higher concentrations of OH−, Na+, silica and aluminium compared to Portland cement (PC). This relatively high alkalinity contributes to the generation of a passive film, which has positive effects on the corrosion resistance of reinforcement steel embedded in AAMs. The silica-aluminium zeolite layer present on the surface of passive film adsorbs chloride ions and effectively inhibits chloride-induced depassivation. Generally, lower ratios of [Cl−]/[SO42−] and [Cl−]/[S2O32−] potentially inhibit the depassivation of reinforcement steel. The high pH value and the elevated concentrations of HS− of AAMs contribute to the increase of critical chloride content (Ccrit). However, the higher content of reduced sulfide mainly dissolved from slag results in the consumption of dissolved oxygen, which is necessary for the formation of passive film. Generally, the presence of reduced sulfide forms Fe-S complexes on the surface of reinforcement steel in AAMs. Even so, higher corrosion resistance for AAMs is mostly expected with longer depassivation time due to finer microstructure and lower chloride penetration rates compared to PC-based materials. The decrease in pH value in the pore solution of the AAMs is the main factor affecting carbonation-induced depassivation of reinforcement steel, while high concentrations of bicarbonate and carbonate ions inhibit depassivation.

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.

Hyperchloremic metabolic acidosis potentially benefiting sodium bicarbonate therapy: A multi-center cohort study

BackgroundThe use of sodium bicarbonate for metabolic acidosis has been a topic of debate, primarily due to the lack of clinical efficacy evidence. This study aims to identify which types of patients with various acid-base balance parameters can benefit from sodium bicarbonate therapy. MethodsPatients diagnosed with metabolic acidosis were screened from a large multi-center critical care database to form a retrospective cohort. Mortality curves, logistic regression analysis, simulation methods, and propensity scores were used to compare data between sodium bicarbonate (SOB group) and non-treated (Non-SOB group) patients. ResultsThere was an interaction between baseline chloride, anion gap levels and sodium bicarbonate therapy on patients' in-hospital death. As chloride levels increased, the in-hospital mortality curves of the SOB group and Non-SOB group gradually converged, with the difference narrowing from approximately 20 % to 10 %, and then gradually widened with the increase of the anion gap. Furthermore, when patients had high chloride levels (≥112 mmol/L), those in the SOB group exhibited a higher incidence of hypernatremia, hypokalemia, and hypocalcemia at 24 h, and a lower incidence of hyperchloremia. Patients in SOB group also had a lower simulated mortality. Among patients treated with sodium bicarbonate, those with low chloride had more difficulty in normalizing pH compared to those with high chloride. ConclusionsThis study identified an interaction between baseline chloride and sodium bicarbonate therapy on patient survival. Hyperchloremic metabolic acidosis may potentially benefit from sodium bicarbonate therapy. Further prospective randomized controlled studies are warranted.

Incidence of Acute Kidney Injury and Mortality in Critically Ill Patients: Urinary Chloride as a Prognostic Marker

Abstract Background Acute kidney injury (AKI) is characterized by a rapid decrease in renal function. It is frequent in hospitalized patients and its incidence is higher in critically ill patients. It is associated with high rates of morbidity and mortality. AKI affects over 13 million people per year globally, and results in 1.7 million deaths. It is diagnosed in up to 20% of hospitalized patients and in 30– 60% of critically ill patients. It is the most frequent cause of organ dysfunction in intensive care units and the occurrence of even mild AKI is associated with a 50% higher risk of death. Objective To investigate the association between urinary chloride concentrations, AKI and mortality. Patients and Methods This prospective observational study has been carried out in Ain Shams University ICUs and included 90 critically ill patients with acute kidney injury during a study period of 6 months. Results Our results support a statistically high significant increase in serum chloride levels among non survival cases on the first day of ICU admission, till the 9th day. The present study revealed that urinary chloride level was significantly higher among survivors’ group on all days of ICU admission. There was a significant decrease in overall survival among AKI patients as they had longer ICU stay and 48.8% mortality rate (all non-AKI patients were discharged alive by 4th day). Conclusion We found that a lower urinary chloride concentration at the time of ICU admission was associated with higher mortality and higher incidence of AKI in critically ill patients. Urinary chloride measurement may constitute an early and useful prognostic marker for assessment of patients in ICU.

Unraveling Lattice Dislocation‐Driven Energy Band Convergence Mechanism to Enhance Electrocatalytic Hydrogen Production in Alkaline Seawater

AbstractHydrogen evolution reaction (HER) from seawater electrolysis still faces challenges of low reactivity and chloride ions poison at the active sites, leading to reduced efficiency and stability of electrocatalysts. This study presents edge dislocation strategy aimed at inducing lattice strain in ferric oxide through Mo doping, consequently regulating the catalyst's band structure. Through in situ characterizations and DFT analysis, it is confirmed that lattice strain effectively modulates the band structure, intensifies the hybridization between Mo(d)‐Fe(d)‐O(p) orbitals, thereby accelerating the charge transfer rate of HER. Furthermore, band structure modulated by lattice strain enhances water adsorption capacity, reduces the adsorption energy of Cl−, and optimizes the hydrogen adsorption‐free energy (ΔGH*) for HER. Benefiting from above, the optimized 2%‐Mo‐Fe2O3 catalyst demonstrates HER activity and stability in alkaline seawater electrolysis comparable to that of commercial Pt/C. Additionally, the assembled electrolytic cell utilizing an anion exchange membrane (AEM) maintains long‐term stability for >100 h at 500 mA cm−2, showcasing a sustained catalytic effect.

Unraveling the impact of pH, sodium concentration, and medium osmolality on Vibrio natriegens in batch processes

BackgroundVibrio natriegens, a halophilic marine γ-proteobacterium, holds immense biotechnological potential due to its remarkably short generation time of under ten minutes. However, the highest growth rates have been primarily observed on complex media, which often suffer from batch-to-batch variability affecting process stability and performance. Consistent bioprocesses necessitate the use of chemically defined media, which are usually optimized for fermenters with pH and dissolved oxygen tension (DOT) regulation, both of which are not applied during early-stage cultivations in shake flasks or microtiter plates. Existing studies on V. natriegens’ growth on mineral media report partially conflicting results, and a comprehensive study examining the combined effects of pH buffering, sodium concentration, and medium osmolality is lacking.ResultsThis study evaluates the influence of sodium concentration, pH buffering, and medium osmolality on the growth of V. natriegens under unregulated small-scale conditions. The maximum growth rate, time of glucose depletion, as well as the onset of stationary phase were observed through online-monitoring the oxygen transfer rate. The results revealed optimal growth conditions at an initial pH of 8.0 with a minimum of 300 mM MOPS buffer for media containing 20 g/L glucose or 180 mM MOPS for media with 10 g/L glucose. Optimal sodium chloride supplementation was found to be between 7.5 and 15 g/L, lower than previously reported ranges. This is advantageous for reducing industrial corrosion issues. Additionally, an osmolality range of 1 to 1.6 Osmol/kg was determined to be optimal for growth. Under these optimized conditions, V. natriegens achieved a growth rate of 1.97 ± 0.13 1/h over a period of 1 h at 37 °C, the highest reported rate for this organism on a mineral medium.ConclusionThis study provides guidelines for cultivating V. natriegens in early-stage laboratory settings without pH and DOT regulation. The findings suggest a lower optimal sodium chloride range than previously reported and establish an osmolality window for optimal growth, thereby advancing the understanding of V. natriegens’ physiology. In addition, this study offers a foundation for future research into the effects of different ions and carbon sources on V. natriegens.

Corrosion behavior of ASTM A416 tendon steel in wet conditions under various chloride concentrations

This study examines the corrosion behavior of steel tendons for prestressed concrete (PSC) structures under varying chloride concentrations and [Cl-]/[OH-] ratios. Tendons were exposed to controlled wet conditions, with chloride concentrations ranging from 0.0 to 0.25 mol/L, and [Cl-]/[OH-] ratios from 0.3 to 0.9. Results showed significant corrosion even at low chloride levels, with corrosion current density escalating from "high-risk" to "severe" as chloride concentration increased. The study also found that complete grouting is critical, as tendons exposed to humid environments without proper protection corrode significantly, irrespective of the chloride content. The findings suggest that traditional "critical chloride content" concepts may not apply to PSC tendons, highlighting the need for meticulous grout quality control to prevent corrosion. This research provides essential insights into the factors influencing tendon corrosion, offering guidance for improving PSC durability.

Drying-Wetting Correlation Analysis of Chloride Transport Behavior and Mechanism in Calcium Sulphoaluminate Cement Concrete.

In response to rising CO2 emissions in the cement industry and the growing demand for durable offshore engineering materials, calcium sulphoaluminate (CSA) cement concrete, known for its lower carbon footprint and enhanced corrosion resistance compared to Ordinary Portland Cement (OPC), is increasingly important. However, the chloride transport behavior of CSA concrete in both laboratory and marine environments remains underexplored and controversial. Accordingly, the chloride ion transport behaviors and mechanisms of CSA concrete in laboratory-accelerated drying-wetting cyclic environments using NaCl solution and seawater, as well as in marine tidal environments, were characterized using the rapid chloride test (RCT), X-ray diffraction (XRD), mercury infiltration porosimetry (MIP), and thermogravimetric analysis (TGA). The results reveal that CSA concrete accumulates more chloride ions in NaCl solution than in seawater, with concentrations 2-3.5 times higher at the same water-cement ratio. Microscopic analysis indicates that calcium and sulfate ions present in seawater facilitate the regeneration of ettringite, thereby increasing the density of the surface pore structure. The hydration and repair mechanisms of CSA concrete under laboratory conditions closely resemble those in marine tidal conditions when exposed to seawater. Additionally, this study found that lower chloride ion concentrations and pH levels inhibit the formation of Friedel's salt. Therefore, laboratory experiments with seawater can effectively simulate CSA concrete's chloride transport properties in marine tidal environments, whereas NaCl solution does not accurately reflect actual marine conditions.

Urinary chloride excretion in critical illness and acute kidney injury: a paediatric hypothesis-generating cohort study post cardiopulmonary bypass surgery.

Renal chloride metabolism is currently poorly understood but may serve as both a diagnostic and a treatment approach for acute kidney injury. We investigated whether plasma chloride, ammonia and glutamine as well as urinary chloride, ammonium and glutamine concentrations may serve as markers for acute kidney injury in paediatric patients. We conducted a prospective observational trial in a tertiary care paediatric intensive care unit. Ninety-one patients after cardiopulmonary bypass surgery were enrolled. Plasma glutamine, creatinine, (serum) albumin, urinary electrolytes and glutamine were collected pre-cardiopulmonary bypass surgery, at paediatric intensive care unit admission, and at 6, 12, 24, 48 and 72 h after paediatric intensive care unit admission. The urinary strong ion difference was calculated. The median urinary chloride excretion decreased from 51 mmol/L pre-cardiopulmonary bypass to 25 mmol/L at paediatric intensive care unit admission, and increased from 24 h onwards. Patients with acute kidney injury had lower urinary chloride excretion than those without. The median urinary strong ion difference was 59 mmol/L pre-cardiopulmonary bypass, rose to 131 mmol/L at 24 h and fell to 20 mmol/L at 72 h. The plasma chloride rose from 105 mmol/L pre-cardiopulmonary bypass to a maximum of 109 mmol/L at 24 h. At 24 h the plasma chloride concentration was associated with the presence of acute kidney injury. There was no association between plasma or urinary amino acids and chloride excretion or kidney injury. In conclusion, renal chloride excretion decreased in all patients, although this decrease was more pronounced in patients with acute kidney injury. Our findings may reflect a response of the kidneys to critical illness, and acute kidney injury may make these changes more pronounced. Targeting chloride metabolism may offer treatment approaches to acute kidney injury.

Electrochemical Behavior of Plasma-Nitrided Austenitic Stainless Steel in Chloride Solutions.

The application possibilities of austenitic stainless steels in high friction, abrasion, and sliding wear conditions are limited by their inadequate hardness and tribological characteristics. In order to improve these properties, the thermochemical treatment of their surface by plasma nitriding is suitable. This article is focused on the corrosion resistance of conventionally plasma-nitrided AISI 304 stainless steel (530 °C, 24 h) in 0.05 M and 0.5 M sodium chloride solutions at room temperature (20 ± 3 °C), tested by potentiodynamic polarization and electrochemical impedance spectroscopy. Optical microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy are used for nitrided layer characterization. The experiment results confirmed the plasma-nitrided layer formation of increased micro-hardness related to the presence of Cr2N chromium nitrides and higher surface roughness compared to the as-received state. Both of the performed independent electrochemical corrosion tests point to a significant reduction in corrosion resistance after the performed plasma nitriding, even in a solution with a very low chloride concentration (0.05 mol/L).

Genotype-phenotype correlations in children with Gitelman syndrome.

This study aimed to analyze genotype-phenotype correlations in children with Gitelman syndrome (GS). This multicenter retrospective study included 50 Korean children diagnosed with SLC12A3 variants in one or both alleles and the typical laboratory findings of GS. Genetic testing was performed using the Sanger sequencing except for one patient. The median age at the diagnosis was 10.5years (interquartile range, 6.8;14.1), and 41 patients were followed up for a median duration of 5.4years (interquartile range, 4.1;9.6). A total of 30 different SLC12A3 variants were identified. Of the patients, 34 (68%) had biallelic variants, and 16 (32%) had monoallelic variants on examination. Among the patients with biallelic variants, those (n=12) with the truncating variants in one or both alleles had lower serum chloride levels (92.2±3.2 vs. 96.5±3.8mMol/L, P=0.002) at onset, as well as lower serum potassium levels (3.0±0.4 vs. 3.4±0.3mMol/L, P=0.016), and lower serum chloride levels (96.1±1.9 vs. 98.3±3.0mMol/L, P=0.049) during follow-up than those without truncating variants (n=22). Patients with monoallelic variants on examination showed similar phenotypes and treatment responsiveness to those with biallelic variants. Patients with GS who had truncating variants in one or both alleles had more severe electrolyte abnormalities than those without truncating variants. Patients with GS who had monoallelic SLC12A3 variants on examination had almost the same phenotypes, response to treatment, and long-term prognosis as those with biallelic variants.

Persulfate activation by biochar and iron: Effect of chloride on formation of reactive species and transformation of N,N-diethyl-m-toluamide (DEET)

Fenton-like processes using persulfate for oxidative water treatment and contaminant removal can be enhanced by the addition of redox-active biochar, which accelerates the reduction of Fe(III) to Fe(II) and increases the yield of reactive species that react with organic contaminants. However, available data on the formation of non-radical or radical species in the biochar/Fe(III)/persulfate system are inconsistent, which limits the evaluation of treatment efficiency and applicability in different water matrices. Based on competition kinetics calculations, we employed different scavengers and probe compounds to systematically evaluate the effect of chloride in presence of organic matter on the formation of major reactive species in the biochar/Fe(III)/persulfate system for the transformation of the model compound N,N‑diethyl-m-toluamide (DEET) at pH 2.5. We show that the transformation of methyl phenyl sulfoxide (PMSO) to methyl phenyl sulfone (PMSO2) cannot serve as a reliable indicator for Fe(IV), as previously suggested, because sulfate radicals also induce PMSO2 formation. Although the formation of Fe(IV) cannot be completely excluded, sulfate radicals were identified as the major reactive species in the biochar/Fe(III)/persulfate system in pure water. In the presence of dissolved organic matter, low chloride concentrations (0.1 mM) shifted the major reactive species likely to hydroxyl radicals. Higher chloride concentrations (1 mM), as present in a mining-impacted acidic surface water, resulted in the formation of another reactive species, possibly Cl2•−, and efficient DEET degradation. To tailor the application of this oxidation process, the water matrix must be considered as a decisive factor for reactive species formation and contaminant removal.

Acidic process fluid from hydrothermal carbonization improves dechlorination of waste PVC and produces clean solid and liquid fuels

Dechlorination of waste PVC (WPVC) by hydrothermal treatment (HTT) is a potential technology for upcycling WPVC in order to create non-toxic products. Literature suggests that acids can improve the HTT process, however, acid is expensive and also results in wastewater. Instead, the acidic process fluid (PF) of hydrothermal carbonization (HTC) of orange peel was utilized in this study to enhance the dechlorination of WPVC during HTT. Acidic HTT (AHTT) experiments were carried out utilizing a batch reactor at 300–350 °C, and 0.25–4 h. The finding demonstrated that the dechlorination efficiency (DE) is high, which indicates AHTT can considerably eliminate chlorine from WPVC and relocate to the aqueous phase. The maximum DE of 97.57 wt% was obtained at 350 °C and 1 h. The AHTT temperature had a considerable impact on the WPVC conversion since the solid yield decreases from 56.88 % at 300 °C to 49.85 % at 350 °C. Moreover, AHTT char and crude oil contain low chloride and considerably more C and H, leading to a considerably higher heating value (HHV). The HHV increased from 23.48 to 33.07 MJ/kg when the AHTT time was raised from 0.25 to 4 h at 350 °C, indicating that the AHTT time has a beneficial effect on the HHV. The majority fraction of crude oil evaporated in the boiling range of lighter fuels include gasoline, kerosene, and diesel (57.58–83.09 wt%). Furthermore, when the AHTT temperature was raised from 300 to 350 °C at 1 h, the HHV of crude oils increased from 26.11 to 33.84 MJ/kg. Crude oils derived from AHTT primarily consisted of phenolic (50.47–75.39 wt%), ketone (20.1–36.34 wt%), and hydrocarbon (1.08–7.93 wt%) constituents. In summary, the results indicated that AHTT is a method for upcycling WPVC to clean fuel.

Combined effect of supplementary cementitious materials and hot-dipped galvanized steel on performance of reinforced concretes subjected to chloride-induced corrosion

Concrete specimens with three types of cement (sulfate resistant high early strength – reference, pozzolanic, and with ground granulated blast furnace slag) reinforced with two types of steel (galvanized and carbon steel) were subjected to cycles of immersion in 1.0 M NaCl solution and drying at 40ºC. For each different steel-concrete condition, 6 rebars were tested. Experimental results show that galvanized steel presents longer corrosion initiation periods in concretes with supplementary cementitious materials. Particularly for pozzolanic concrete, this increased initiation period was 4.6 times longer on average, which reflects, in a similar way, on service-life simulations. In general, the average chloride thresholds of galvanized steel increased with a decrease in pore solution alkalinity. Compared to carbon steel, higher chloride thresholds were found for galvanized steel embedded in the lower alkalinity concrete matrix (calculated pore pH = 12.6). On the other hand, galvanized steel presented lower chloride thresholds for more alkaline pore pHs (pozzolanic and reference concretes).