High Concentration Of Chloride Ions Research Articles

Analysis of Poultice-Based Desalination of a Nineteenth Century Brick and Stone Cathedral after the Event; A Longitudinal Study of Surface Chloride Readings

St George’s Cathedral in Perth was consecrated in 1888 and constructed using hand-made bricks and limestone. After 120 years of exposure to salt-laden winds, rising salty water and leaky roofs significant deterioration due to salt efflorescence and water penetration necessitated an $18 million AUD restoration program in 2002. Before accepting the heritage architect’s proposal to replace all the worst damaged brick and stone elements, surface chloride activity mapping of the affected areas was conducted. The survey found that the worst decay was associated with high chloride ion concentrations, with a maximum value of 10,000 ppm on a brick buttress and 7,600 ppm on a stone colonnade on the west front. After four months of treatment, the Westox Cocoon papier-mâché pulp poultice had lowered the surface chloride readings to 10 ± 5 ppm on the bricks and stone. Ten years after the work, a series of tests were conducted on salt-damaged reference stone and bricks to find formulae for converting surface chloride readings into weight percent extractable chloride concentrations. This data was then retrospectively applied to the treated cathedral fabric to estimate how much chloride had been removed. Without the poultice treatment, large sections of the original fabric would have been lost.

Removal of chloride ions from a copper leaching solution, using electrodialysis, to improve the uranium extraction through ion-exchange

This study shows the technical feasibility to recover uranium from copper Pregnant Leaching Solutions (PLS) using ion-exchange, after a removal of chloride ions using the electrodialysis (ED) technique. The original copper PLS solutions came from the National Copper Corporation (CODELCO), from their hydrometallurgical operations, which contained high concentrations of chloride ions. These solutions contained average concentrations of 22 g/L chloride ions, pH 1.5 – 1.8 and 20 mg/L uranium. The high chloride contents made the uranium recovery technically unfeasible, because of the high volumes of chemical reagents needed to operate. To eliminate the chloride ions selectively, a modified electrodialysis (ED) process was developed. The ED process was made of a three–compartment cell. This system removed selectively the chloride ions, and replaced them with sulphuric ions, without modifying the composition of the copper PLS solution, to allow a continuous operation of the copper production plant. The ED process decreased the chloride content from 22 g/L to 6 g/L. Finally, static and dynamic load tests were performed for both the original PLS and the treated PLS, using 3 different anion-exchange resins: Dowex-1, Lewatit A365 and Lewatit MP62-WS. The loading capacity of the ion-exchange resins was increased 4 times approximately.

Electrochemical Corrosion Behaviour of Carbon Steel in Concrete with Metakaolin Admixture Exposed to Soil with High Concentration of Chloride Ions

Electrochemical Corrosion Behaviour of Carbon Steel in Concrete with Metakaolin Admixture Exposed to Soil with High Concentration of Chloride Ions

Influence of NaCl concentration on microbiologically influenced corrosion of carbon steel by halophilic archaeon Natronorubrum tibetense

The influence of NaCl concentration on microbiologically influenced corrosion (MIC) of Q235 carbon steel by the halophilic archaeon Natronorubrum tibetense was investigated by immersion tests and electrochemical measurements. An increase in NaCl concentration from 0 g/mL to 0.1 g/mL promoted the anodic dissolution of carbon steel and accelerated its corrosion, but MIC did not occur. A further increase in NaCl concentration to 0.2 g/mL led to MIC in inoculated medium, and the occurrence of the MIC resulted in further aggravation of carbon steel corrosion. Once the NaCl concentration reached 0.3 g/mL, the high concentration of chloride ions greatly interfered with the adsorption of dissolved oxygen and the attachment of N. tibetense cells to the surface of carbon steel, thus reducing the corrosion rate of carbon steel and inhibiting the MIC.

High concentrations of sodium and chloride ions have opposing effects on the growth of the xerophyte Pugionium cornutum under saline conditions

AbstractBackground: The research on plant salt tolerance has mainly focused on Na+, but Cl− has been relatively neglected. Previous studies have found that the xerophyte Pugionium cornutum, an important forage grass in the arid and semi‐arid regions of northwestern China, could synergistically accumulate high quintiles of Na+ and Cl− in its shoots under NaCl treatments. However, the separate effects of these ions on the adaptation of P. cornutum to saline conditions have not been investigated.Aims: In this study, the response of P. cornutum to Na+ and Cl− was analyzed.Methods: Four‐week‐old seedlings were treated with additional 50 mM NaCl, Na+‐specific solution containing 50 mM Na+ with a mix of , H2 , and as counter anions, and Cl−‐specific solution containing 50 mM Cl− with a mix of K+, Ca2+, and Mg2+ as counter cations.Results: Compared with the normal growth condition irrigated with Hoagland solution, the Na+‐specific solution severely impaired the growth and photosynthesis of P. cornutum due to the high accumulation of Na+ in shoots and the deterioration of tissue K+ homeostasis; while the Cl−‐specific solution significantly increased shoot fresh and dry biomass. The Cl−‐specific solution could also increase the turgor pressure in leaves for enhancing osmotic adjustment, which should be mainly attributed to the large accumulation of Cl−, since the concentrations of other ions, including K+, Mg2+, Ca2+, H2 , and , in tissues under Cl−‐specific treatment were maintained at the same levels as those observed under the normal condition.Conclusions: P. cornutum displays an excellent tolerance to moderate Cl− but not to Na+, and the large accumulation of Cl− should play a positive role in stimulating the growth of P. cornutum under salt stress.

Groundwater flow and chloride transport modeling of the alluvial aquifer of lower Soummam Valley, Béjaia, North-East of Algeria

Resulting from lithological conditions and anthropogenic activities as fertilizers use and wastewater discharge, high concentrations of chloride ions were revealed in both surface water and groundwater in Lower Soummam valley, situated in the North-Eastern of Algeria. Using geological, hydrogeological and geochemical data, a conceptual model was designed in order to improve understanding of chloride mass movements within the aquifer. A groundwater flow using PMWIN, coupled with a solute transport numerical model using MT3D code was run. Following a steady state stress period, four transient stress periods were added in order to simulate groundwater level evolution from 2011 to 2030. Groundwater withdrawals, providing from the National Plan of Water, were increased and vertical recharge rate was progressively reduced. Respecting an optimal management of water resources suitable for arid and semi-arid watersheds, successive tests have been conducted in order to mitigate the influence of high pumping rates and low recharge conditions. Recognized as a major term in water budget, water inflows from lateral boundaries representing 54.4%. At the river–aquifer interface, water was exchanged in both upward and downward representing 18% of the total amount of inflow. In coherence with experimental data, simulations indicate an impact of exchange fluxes across the river-aquifer interface. The Cl model simulations show a substantial decrease of Cl loads. According to good hydraulic properties, 90% of simulated wells show a gradual decline in their calculated concentrations, almost located on El Kseur-Oued Ghir pathway. Simulation results could be integrated in the future water resource management plan of Soummam Valley. Such a predictive model, it will be used to lay down water quality restoration strategy.

Transient Dynamics of Archaea and Bacteria in Sediments and Brine Across a Salinity Gradient in a Solar Saltern of Goa, India.

The microbial fluctuations along an increasing salinity gradient during two different salt production phases – initial salt harvesting (ISH) phase and peak salt harvesting (PSH) phase of Siridao solar salterns in Goa, India were examined through high-throughput sequencing of 16S rRNA genes on Illumina MiSeq platform. Elemental analysis of the brine samples showed high concentration of sodium (Na+) and chloride (Cl–) ions thereby indicating its thalassohaline nature. Comparison of relative abundance of sequences revealed that Archaea transited from sediment to brine while Bacteria transited from brine to sediment with increasing salinity. Frequency of Archaea was found to be significantly enriched even in low and moderate salinity sediments with their relative sequence abundance reaching as high as 85%. Euryarchaeota was found to be the dominant archaeal phylum containing 19 and 17 genera in sediments and brine, respectively. Phylotypes belonging to Halorubrum, Haloarcula, Halorhabdus, and Haloplanus were common in both sediments and brine. Occurence of Halobacterium and Natronomonas were exclusive to sediments while Halonotius was exclusive to brine. Among sediments, relative sequence frequency of Halorubrum, and Halorhabdus decreased while Haloarcula, Haloplanus, and Natronomonas increased with increasing salinity. Similarly, the relative abundance of Haloarcula and Halorubrum increased with increasing salinity in brine. Sediments and brine samples harbored about 20 and 17 bacterial phyla, respectively. Bacteroidetes, Proteobacteria, and Chloroflexi were the common bacterial phyla in both sediments and brine while Firmicutes were dominant albeit in sediments alone. Further, Gammaproteobacteria, Alphaproteobacteria, and Deltaproteobacteria were observed to be the abundant class within the Proteobacteria. Among the bacterial genera, phylotypes belonging to Rubricoccus and Halomonas were widely detected in both brine and sediment while Thioalkalispira, Desulfovermiculus, and Marinobacter were selectively present in sediments. This study suggests that Bacteria are more susceptible to salinity fluctuations than Archaea, with many bacterial genera being compartment and phase-specific. Our study further indicated that Archaea rather than Bacteria could withstand the wide salinity fluctuation and attain a stable community structure within a short time-frame.

A High‐sensitivity and Enzyme‐free Clenbuterol Sensor using SWCNT Arrays Prepared with a One‐pot Method Comprising Gold Nanoparticles and Cl−

AbstractWe describe a novel enzyme‐free sensor for clenbuterol (CLE) prepared by a simple electrochemical method. A new method to detect clenbuterol hydrochloride was developed by single‐walled carbon nanotubes (SWCNTs) arrays and gold nanoparticles (AuNPs)‐Cl− complex. SWCNT arrays modified glass carbon electrode (GCE) was first prepared by one‐pot method with cyclic voltammetry.Then AuNPs were deposited on the SWCNT arrays and complexed with a high concentration of chloride ions (0.1 mol/L). The as‐fabricated SWCNT arrays/AuNPs senor have showed an excellent sensitivity in CLE detection with lower detection limit (0.5 ng/L) and wider linear range (1–800 ng/L). Its high performance can be attributed to the high catalytic activity of SWCNT arrays and the special absorption of CLE on AuNPs. The surface morphology of the electrode was analyzed by atomic force microscopy, X‐ray photoelectron spectroscopy and SEM. This work offers a new method for the synthesis of SWCNT arrays and a novel avenue for CLE detection. The modified electrode was stable with 98.5 % of its initial current response after remained one month, it was used to detect CLE in human urine, animal tissues and food with satisfactory results.

Modeling the corrosion of steel casing and the damage of well cement in a borehole system

This paper presents the effect of chloride-induced corrosion in an underground borehole system, specifically considering the steel casing and further damage to the surrounding cement. In the past four decades, oil well cement has been successfully used for underground construction. However, high concentrations of chloride ions gradually degrade the functionality and durability of well cement. Gasses and liquids can leak from deterioration caused by chloride ions, and thus motivate this study. The chemo-mechanical coupling diffusion model and a classical fracture mechanics model are applied. The model is validated with OPC concrete corrosion data from literature, and then applied to well cement using experimentally obtained material property data. The time when crack initiation, peak pressure, and complete fracture is reached in the model of the cement sheath provides a quantification of the expected service life of the borehole system.

Effects of the α/γ-Phase Ratio on the Corrosion Behavior of Cast Duplex Stainless Steel

The effects of the α/γ-phase ratio on pitting corrosion initiation and growth in cast duplex stainless steel were studied, including the preferential dissolution of the two phases inside the pits, using pitting potential measurement and potentiostatic polarization measurement with a high concentration of chloride ions and a low pH. The initiation of pitting was not dependent on the α-phase ratio. The γ phase preferentially dissolves when a high potential in the active dissolution region is applied, and the α phase preferentially dissolves when a low potential is applied. In addition, with an increase in α-phase ratio, the potential range where the α phase preferentially dissolves enlarged toward the higher potential side. The growth rate of stable pitting increased with the α-phase ratio. Dissolution of the α phase increased with an increase in the α-phase ratio. This phenomenon is presumably caused by the decreased amount of Cr in the α phase, resulting from the increased α-phase ratio, as well as by Cr depletion around Cr nitrides.

Individual and additive stress impacts of Na+ and Cl‾ on proline metabolism and nitrosative responses in rice

It is well-established that plants accumulate high concentrations of sodium (Na+) and chloride (Cl‾) ions when subjected to salinity stress. However, little is known about individual or relative toxic impacts of these ions and whether they exert additive impacts under NaCl. Most of the investigations have historically been directed to decode Na+-toxicity, and as a result deeper understandings about Cl‾-toxicity are lacking. In this study, the extent to which sodium and chloride ions contribute in inducing nitrosative responses and proline metabolism is shown in two rice cultivars, one tolerant (Panvel-3) and one sensitive (Sahyadri-3). Equimolar (100 mM) concentrations of Na+, Cl‾ and NaCl (EC ≈ 10 dSm−1) reduced biomass production in both the cultivars in following manner NaCl > Na+>Cl‾. Na+ and NaCl treatments displaced K+, however, the tolerant cultivar maintained low Na+/K+ levels. Hyper-accumulation of Na+ may apparently be attributed for the reduced plant growth and biomass accumulation, and higher lipid-peroxidation. Nitric oxide and nitrate reductase were more responsive to NaCl followed by Na+ and Cl‾, respectively. The expression patterns of key-genes involved in proline biosynthesis and degradation confirmed the involvement of proline in better performance of salt tolerant cultivar under stresses, with higher responsiveness to NaCl and then Na+ and Cl‾ treatments. Principal component analysis revealed correlations in proline metabolism and nitrosative responses under ionic stresses and confirmed the closeness of NaCl and Na+ stresses. Overall, amongst the individual ions, Na+ induced higher toxicity than Cl‾ and both these ions exerted additive stress impacts under NaCl treatment.

Experimental and theoretical characterization of commercial nanofiltration membranes for the treatment of ion exchange spent regenerant

This work presents a joint experimental and simulation campaign aimed at characterizing two nanofiltration membranes (TS80 and NF270) in the presence of a multi-ionic water solution simulating the spent regenerant of cationic ion exchange resins employed for water softening. We identified the membrane parameters, which allowed for predicting the performances through the Donnan Steric Pore Model with Dielectric Exclusion. A good agreement between model and experimental trends of rejection as a function of the applied pressure was observed (error < 15%). The analysis of trans-membrane fluxes and exclusion coefficients showed that dielectric exclusion was the crucial mechanism for the ionic partition. In fact, the lower pore dielectric constant found for TS80 justified the higher rejections to divalent cations with respect to NF270. Moreover, negative charge densities were found for both membranes, because of the high concentration of chloride ions in the feed, which likely adsorbed onto the membrane. However, it was observed that the experimental rejections did not change significantly with the feed pH. This result, in line with the minor role of the Donnan exclusion resulting from the model, suggested that the membrane performances were not much affected by the charge density at high feed ionic strengths (~1 M).

Experimental Study on Chloride Ion Removal in High-Salt Wastewater System

Chlorine is usually present in the environment in an ionic state, is highly mobile and difficult to degrade. High-chlorine wastewater can corrode buildings and affect the growth of animals and plants. Therefore, how to solve the environmental problem of high concentration of chloride ions well and effectively has drawn the intensive attention of the society. In this paper, chloride ion is removed from wastewater with the method of coprous chloride precipitation, and investigation is made on the effects of pH, temperature, amount of precipitant, titration time and reaction time on the removal efficiency of chloride ions. The results show that: when nCuSO4:nNa2SO3:nNaCl: n(ascorbic acid) =1.3:1.1:1: 0.01, and reaction pH is 3, temperature is 80 °C, titration time of sodium sulfite is 20min, reaction time after titration is 30min, the chloride ion has the optimal removal efficiency. SEM method is used for the characterization of the precipitates formed by the reaction. The results show that the experimentally produced complex cuprous chloride is irregular polyhedron with uneven particle size.

ОЦЕНКА ЗАГРЯЗНЕНИЯ ХЛОРИД-ИОНАМИ МАЛЫХ РЕК НИЖНЕВАРТОВСКОГО РАЙОНА

Важное значение в оценке экологической ситуации в Ханты-Мансийском автономном округе представляют концентрации химических веществ в поверхностных водах и донных отложениях, которые характеризуют техногенные потоки загрязняющих веществ в районах нефтепромыслов. Хлоридное загрязнение малых рек приводит к их накоплению в донных отложениях. Высокие концентрации хлорид-ионов в поверхностных водах и донных отложениях негативно воздействуют на речную экосистему.

Lead Chlorides in Paint on a Della Robbia Terracotta Sculpture.

Materials in the paint layers of an early 16th-century painted and glazed terracotta sculpture by Giovanni della Robbia, Pietà, were identified. The presence of the rare lead chloride salts cotunnite (PbCl2) and challacolloite (KPb2Cl5) was confirmed using Raman spectroscopy and electron backscatter diffraction. The well-formed habit of large crystals of challacolloite indicates slow growth from solution. The stability and potential pathways for the in situ formation of lead chloride compounds are discussed. The presence of lead chloride phases in the Pietà indicates the conditions of high chloride ion concentrations (i.e., activities) and/or low pH led to the alteration of the pigment lead white (hydrocerussite, 2PbCO3·Pb(OH)2). This work highlights the role of ion transport in the alteration of materials in cultural heritage objects, emphasizes the importance of considering the role of treatments and environmental factors in changes in materials, and reinforces our awareness of the ongoing chemistry occurring in works of art.

Atmospheric corrosion of carbon steels in tropical and subtropical climates in Southern China

AbstractQ235 and Q345 carbon steels were exposed for up to 24 months at three test sites of tropical and subtropical climate. The atmospheric corrosion kinetics of Q235 and Q345 was studied by weight‐loss measurement. The results show that the ranking of the atmospheric corrosivity from weak to strong of the three test sites is Xishuangbanna, Guangzhou, and Wanning. The kinetics of the atmospheric corrosion process presents two stages with an accelerated second stage in marine environments of high chloride ion content and high relative humidity, whereas no second stage appears in the kinetics curves in rural and industrial urban environments. The corrosion acceleration stage in the marine environment of the Wanning site is attributed mainly to the high chloride ion concentration and loose rust layer structure.

Prediction of chemical oxygen demand (COD) with total organic carbon (TOC) to eliminate the interferences of high concentration of chloride ion in oilfield wastewaters

ABSTRACT Chemical oxygen demand (COD) is one of the most commonly used indexes for monitoring water quality. However, the accuracy of the conventional COD test is significantly affected by the high concentration of chloride ion in water samples. In addition, the conventional COD test results in the production of hazardous wastes including mercury and hexavalent chromium. This study proposed the prediction of COD with total organic carbon (TOC) for monitoring high-chloride wastewater by comparing their relationship using simulated wastewaters and actual oilfield wastewaters from two wastewater treatment stations at Xinjiang oilfield, China. The theoretical analysis and experimental results showed that there are significant linear correlations between the COD and TOC in simulated wastewaters and actual oilfield wastewaters. High correlation coefficients (R) of 0.9777 and 0.9710 between COD and TOC were obtained for oilfield wastewaters from Xinjiang 81# and 91# stations, respectively. By using the established conversion models, the COD values in the two groups of mixed oilfield wastewaters from Xinjiang 81# and 91# stations were successfully predicted, with relative errors <±5%. It was demonstrated that the proposed method could be promisingly used as an alternative for the green determination of COD values in high-chloride oilfield wastewaters while eliminating the hazardous wastes and chloride interferences.

How GABA makes the switch

Neurodevelopment A high concentration of chloride ions in neurons interferes with signaling mediated by the neurotransmitter γ-aminobutyric acid (GABA). The transporter KCC2 extrudes chloride ions, and Watanabe et al. and Pisella et al. examined mice expressing KCC2 with mutations that mimicked constitutive phosphorylation at two regulatory sites (see the Focus by Zamponi). Dephosphorylation of these sites in KCC2 enables GABA to switch from being an excitatory to being an inhibitory neurotransmitter during neurodevelopment, thus allowing the maturation of the neurocircuitry underlying cognition and respiration. Sci. Signal. 12 , eaaw9315, eaay0300, eaay8960 (2019).

Protective Mechanism of Silane on Concrete upon Marine Exposure

Due to the high chloride ion concentration in marine environments, chloride ions can penetrate into concrete, along with the transportation of water molecules, and thus, cause rebar corrosion. This is an important reason for the decrease in the concrete durability. In this paper, by means of the sol–gel synthesis method, a silane emulsion, a silane compound emulsion, and silane compound gel were prepared by using isobutyl triethoxysilane and ethyl orthosilicate (TEOS) as the main raw materials. These silane materials were coated on a concrete surface and then placed in the marine exposure sites of Wheat Island, in Qingdao, for one year. The results show that these silane materials can effectively inhibit the chloride ions transporting in concrete. Upon the increase of the exposure time, the protection ability of the silane emulsion declined gradually, while the silane compound emulsion had stable protective effects. In comparison with the permeability coefficient of chloride ions in the blank test block, the permeability coefficient of chloride ions in the test block coated with the silane emulsion, the composition of silane emulsion, and silane compound gel fell off around 20%, 30%, and 50%, respectively. The test results indicate that the three kinds of protective materials have good inhibition abilities against chloride ion transportation, on which the compound gel had the best effect.

Removal and recovery of chloride ions in concentrated leachate by Bi(III) containing oxides quantum dots/two-dimensional flakes

The high concentration of chloride (Cl−) ions in leachate often has negative effects in their harmless treatments, and the common treatments containing the ion exchange method consume excessive antichlors due to their large particle sizes and unfavorable morphologies. Herein, the antichlors of the Bi(III) containing oxides with quantum dots (QDs) or two-dimensional (2D) structures are first explored for the removal and recovery of Cl− ions in concentrated leachate. By using the QDs/2D flakes constructed antichlors of Bi2O3 and the magnetite Bi-Ti composite, the maximum Cl− removal rates of 61.8% and 66.1% are respectively achieved under the optimum conditions. The higher removal efficiency of the magnetite Bi-Ti composite is contributed by its less stable crystal phases of Bi25FeO40/Bi12TiO20, which can proceed more deeply in the removal of Cl− ions compared with that of Bi2O3. The recovered terminal magnetite Bi-Ti precipitate with Bi2O3/BiOCl heterostructure exhibits excellent photocatalytic activity in the degradation of the dechlorinated leachate, where a total organic carbon removal rate of 87.2% is achieved under UV–vis-near-infrared irradiation. Therefore, the selection of Bi(III) containing oxides opens a promising and high-value method for the removal and recovery of Cl− ions in leachate and other waste waters.