Concentrations Of Chloride Salts Research Articles

Effects of temperature, chloride and perchlorate salt concentration on the metabolic activity of Deinococcus radiodurans

The extremophile bacterium Deinococcus radiodurans is characterized by its ability to survive and sustain its activity at high levels of radiation and is considered an organism that might survive in extraterrestrial environments. In the present work, we studied the combined effects of temperature and chlorine-containing salts, with focus on perchlorate salts which have been detected at high concentrations in Martian regolith, on D. radiodurans activity (CO2 production rates) and viability after incubation in liquid cultures for up to 30 days. Reduced CO2 production capacity and viability was observed at high perchlorate concentrations (up to 10% w/v) during incubation at 0 or 25 °C. Both the metabolic activity and viability were reduced as the perchlorate and chloride salt concentration increased and temperature decreased, and an interactive effect of temperature and salt concentration on the metabolic activity was found. These results indicate the ability of D. radiodurans to remain metabolically active and survive in low temperature environments rich in perchlorate.

Theoretical study of adsorption of sodium, lithium, magnesium and calcium chloride and sulfate salts by pure and Sc-doped B12N12 nanocages and pure boron nitride nanosheet

High concentrations of water-soluble chloride and sulfate salts may cause adverse effects to humans and plants. Boron nitride (BN) nanostructures seem able to remove these water-soluble salts. In addition, Li+, Mg2+, Ca2+, and Na2+ interactions with BN nanostructures have received much attention in fabricating high-performance metal-ion batteries. Accordingly, this study investigated the adsorption of chloride and sulfate salts of Li, Mg, Ca, and Na on pristine and scandium (Sc)-doped B12N12 nanocages and pure BN nanosheet through DFT calculations. Optimizing the structures at the B3LYP/6-31 g (d, p) and M062X/6-311 g (d, p) computational levels indicated very exothermic chemisorption of chloride and sulfate salts on the pure and Sc-doped B12N12 nanocages. The B12N12-LiCl and Sc@B11N12-LiCl complexes showed the highest negative adsorption energies of −26.33 and −57.30 kcal/mol among the chloride salts. The B12N12-MgSO4 and Sc@B12N12-MgSO4 complexes showed the highest adsorption energies of −69.27 and −102.70 kcal/mol among the sulfate salts. Studying the effect of the adsorption process on the electronic properties of the B12N12 nanocage showed a reduction in the energy gap upon the adsorption of all salts on the pure B12N12 nanocage with the lowest energy gap of 3.98 eV for B12N12-MgSO4. The adsorption energies of the individual salts and their complexes on the B12N12 nanosheet at the B3LYP/6-311 g (d, p) level imply the occurrence of physisorption. A significant reduction was observed in the energy gap by adsorbing the salts on the BN nanosheet. Adsorbing CaSO4 and MgSO4 on the BN nanosheet caused the largest variation of 1.71 and 1.56 eV in the energy gap, respectively. The promising results of our study highlight the potential application of BN nanostructures in the removal of various soluble salts and the fabrication of metal-ion batteries.

Bond performance of NSM FRP–concrete interfaces with epoxy under chloride‐salt conditioned environments

AbstractConcrete in coastal areas is susceptible to structural damage caused by corrosion and expansion of reinforcement. Near‐surface mounted (NSM) fiber‐reinforced polymer (FRP) bars have become effective for strengthening damaged reinforced concrete structures. The bonding performance of NSM FRP bars in concrete is a key factor limiting their application and promotion in civil engineering. In this study, the influences of the conditioned environment, such as the chloride salt concentration, immersion time, and bond length of the FRP bar, on the bonding performance were investigated experimentally. First, material properties in a conditioned environment were studied. Subsequently, the failure mode, bond stress–slip curve, and bond strength of the NSM FRP bar in concrete were investigated. Finally, the microstructure and chemical composition of the materials were revealed using scanning electron microscopy and energy‐dispersive spectroscopy (EDS) images of the materials under environmental conditions. The transfer mechanism of NSM FRP bars in concrete with epoxy was revealed. The results showed that the failure modes of the pullout specimens can be divided into epoxy splitting failure and basalt fiber‐reinforced polymer (BFRP) pulling failure. The chloride‐salt concentration was a critical factor affecting the bond properties, and the longer the bond length, the lower the bond strength. The microstructure clearly shows that the degradation of the bonding behavior at the interface of the NSM FRP bar in concrete in a conditioned environment is attributable primarily to the resin damage of the epoxy, resulting in pit corrosion. There was no significant damage to the fibers in the FRP bar, and the degradation was primarily due to resin matrix damage and interfacial debonding. The EDS results showed that the degradation of the epoxy resin and BFRP bars was caused by CO bond and SiO bond fractures, respectively.

Factors affecting free chloride contents of hardened cement paste with a low water-to-binder ratio determined by rapid water extraction

This paper assesses the free chloride content in hardened cement paste with a low water to binder (w/b) ratio by a proposed water extraction method. Key parameters including extraction time, particle size of the sample, types and concentrations of chloride salts are thoroughly investigated to understand their effects on the extraction results. The findings reveal that the increase of extraction time from 1 to 20 min and the decrease of particle size from 0.315-1 mm to 0.045–0.08 mm exhibits limited influence on the hydration degree of cement paste with low w/b ratio during the extraction process. With the increase of extraction time, the extracted chloride content gradually increases. Beyond the 10-min mark, the extracted chloride content stabilizes gradually, indicating a stable status in the extraction process. The content of Friedel's salt remains relatively unchanged throughout the 10min water extraction, while physically bound chloride gradually releases into the extraction water. Almost all physically bound chloride in NaCl and CaCl2 mixed specimens is desorbed within the 10min of extraction time when the particle size is set at 0.045–0.08 mm. However, the physically bound chloride in MgCl2 blended specimens keeps relatively stable when the particle size varies, which is due to the improved chloride binding capacity by M-S-H. The rapid water extraction method is proved suitable for free chloride testing of hardened cement paste with low w/b ratio by controlling suitable parameters. Consequently, the particle size of 0.08–0.16 mm and extraction time of 10 min are recommended for conservative evaluation of free chloride content in hardened cement paste with low w/b ratio.

Influence of chloride salt erosion on the adhesion of asphalt-aggregate interfaces considering mineral anisotropy: insights from molecular dynamics.

Asphalt, a polymer mixture composed of various hydrocarbons, is extensively utilized due to its excellent performance. To evaluate the sensitivity of asphalt concrete to chloride salt damage at the nanoscale, considering the anisotropy of aggregate mineral crystal orientation, molecular dynamic simulations were employed to model the interface interactions between asphalt and aggregate mineral components (silica and calcite) under chloride salt exposure. The wetting processes of water droplets and chloride salt droplets on different crystal surfaces of silica and calcite were analyzed. Furthermore, the adhesive energy, decohesion energy, degradation ratio, and energy ratio of the interaction model between asphalt and aggregate mineral interfaces were analyzed to reveal the variations in the interfaces between the two components. The results demonstrated that the anisotropy of the minerals significantly affects the adhesion energy of asphalt and aggregate. Moreover, the surface hydrophilicity of calcite was larger than that of silica. The interfacial adhesion energy of asphalt-calcite was larger than that of asphalt-silica under dry condition and chloride salt attack, and the interfacial adhesion energy of both asphalt and mineral decreased with the increase of chloride salt concentration. The degradation ratio and energy ratio values of asphalt and calcite were larger than those of asphalt and silica, and the anisotropy of the mineral surface affected the degradation ratio and energy ratio values. This study provides a new method and theoretical basis for further research on the damage mechanism and strengthening measures of asphalt-aggregate under chloride salt attack. To investigate the interaction between asphalt and mineral aggregates under chloride salt erosion, models of asphalt, aggregate, and asphalt/aggregate composite systems were constructed using the Amorphous Cell module in Materials Studio 2020 software. Molecular dynamic simulations of the asphalt/aggregate composite system were then conducted using the Forcite module, employing the COMPASS II force field to describe atomic and molecular interactions. Initially, considering the crystal orientation and surface configuration of the aggregate minerals, the impact of mineral anisotropy on the asphalt-aggregate interface model was analyzed. Subsequently, by simulating the contact states of nano water droplets and chloride salt droplets with different mineral surfaces, the wetting characteristics of nano water droplets on silica and calcite surfaces were determined. Lastly, considering the corrosion effect of chloride solution at different concentrations, the adhesion energy, debonding energy, degradation ratio, and energy ratio of the asphalt-aggregate interface interaction model were analyzed.

Research on the Strength Damage and Permeability Characteristics of Cemented Paste Backfill under Chlorine Salt Erosion and Dry–Wet Cycles

Cement paste backfill (CPB) suffers serious damage and deterioration under the dual erosion conditions of the dry–wet cycle caused by the high chloride salt concentration in mine water and the fluctuation of mine water level. In order to discuss the mechanical properties and permeability characteristics of CPB under erosion, this study designs an immersion experiment for CPB under chloride salt and dry–wet cycle conditions. Through a uniaxial compressive strength (UCS) test, the change law for the mechanical parameters of the CPB was investigated, the strength constitutive equation of the CPB was constructed and the deterioration process of the CPB was analyzed. The penetration test was used to investigate the diffusion characteristics of the packing under chloride salt and dry–wet cycle conditions. The results showed that the strength and Young’s modulus of the CPB initially increased and then rapidly decreased, with maximum decrease rates of 32.2% and 38.2%, respectively. The CPB structure exhibits an initial undamaged stage, an initial damaged stage, a damaged development stage, a damaged destruction stage and a residual damaged stage. The chloride ion penetration depth gradually increased with the number of dry–wet cycles, with a maximum diffusion depth of 20.5 mm. The maximum apparent diffusion coefficient of chloride ion was 18.99 × 10−10 m2/s, and the maximum concentration was 0.303 mol/L. Under the double erosion conditions of chloride salt and dry–wet cycle, the CPB structure was severely damaged.

Evaluation of the Effects of Some Metal Chlorides on the Initial Reaction Rate of Crude Peroxidase from Watermelon Peels

Aims: This study evaluates the effect of some chloride on the initial reaction rates of crude peroxidase from watermelon peels. Study Design: In vitro enzyme assay. Place and Duration of Study: Department of Biochemistry, Faculty of Life Sciences, Ambrose Alli University, Ekpoma, Edo State, Nigeria between April 2021 and June 2021. Methodology: The kinetics of crude peroxidase catalyzed oxidation of 3,5,3′,5′-tetramethylbenzidine (TMB) in the presence of varying concentrations of different chloride salts and hydrogen peroxidase was determined spectrophotometrically at 655nm. The assay mixture contained 2.3 mL of sodium phosphate buffer of pH 7.0, 0.1 mL of a crude enzyme from the watermelon peels, 0.2 mL of varying concentration of the respective chloride salts, 0.2 mL of 0.02 mM TMB, and 0.2 mL of 2 mM hydrogen peroxidase added last to start the reaction. Results: Results showed that chloride salts of Pb2+ Hg2+ Fe2+ and Na+ had peroxidase activating effects at low salt concentration (1 mM). The activating effect increased proportionately up to their respective optimum salt concentration. Further increment of salt concentration above their respective optimum value lead to a decrease in initial reaction rate of the crude enzyme. Within a chloride concentration range of 0.025 mM to 3 mM, the highest activating effect recorded was in the order Pb2+ > Fe2+ > Na+ > Hg2+.. Results show that Pb2+ had the highest enzyme activating effect at the lowest concentration (0.5 mM) of the salt when compared with other salts within the same concentration range. Conclusion: These findings are of great significance in research to understanding the mechanism of action of peroxidase from the peels of watermelon, especially as the search for cheap and alternative sources of peroxidases continues.

Extracting zinc from ironworking dust having a high zinc content by vacuum silicothermic reduction

Zinc dust having a high ZnO content can be obtained after the preliminary treatment of zinc-bearing dust generated by the iron and steel industry by using a rotary kiln. However, this material has a high concentration of chloride salts that can affect the hydro-metallurgical extraction of metallic zinc. The present study used a vacuum distillation-vacuum thermal reduction process to recover zinc metal from this dust. This process first separated chloride and PbO by vacuum distillation and then extracted metallic zinc via the vacuum silicothermic reduction of ZnO. The results show that high-purity ZnO was prepared by vacuum distillation using the original zinc dust as a raw material. Both alkali metal chlorides and PbO in the dust could be removed with greater than 99 % efficiency by vacuum distillation at 1000 °C. Following this step, the slag contained more than 80 wt% Zn but less than 0.01 wt% chlorine and PbO. The vacuum thermal reduction process used the slag obtained from distillation as the raw material together with ferrosilicon alloy as a reducing agent. ZnO was reduced above 1000 °C and the recovery of this oxide exceeded 99 % using a reduction temperature of 1200 °C, reduction time of 2 h, and ferrosilicon mass ratio of 0.27. The main phase in the slag after reduction was SiO2 and the ZnO concentration was below 1 wt%, indicating a purity greater than 99 %. This method can realize the separation, recovery, and reuse of zinc-bearing dust to maximize the value-added utilization of this resource.

Analysis of nanoscale evolution features of microstructure of asphalt based on atomic force microscopy

To reveal the microstructural evolution of asphalt at the nanoscale, this study utilizes an atomic force microscope (AFM) to observe the surface morphology of asphalt and employs roughness theory for its quantitative assessment. The effects of asphalt type, aging state, immersion time, chloride salt concentration, and modifiers on beelike structures and roughness were comprehensively considered. The results demonstrated that the area and number of beelike structures, as well as the roughness, varied with different asphalt types. After aging, the surface morphology of the asphalt became rougher, leading to an increase in surface roughness, while both the number and area of the beelike structures in the asphalt showed a decreasing trend. With increasing immersion time, water penetrated into the asphalt and interacted with its components, disrupting the colloidal structure under dry conditions and causing microstructural damage and peeling. Consequently, distinct nanoscale protrusions and white spots appeared on the asphalt surface. Moreover, the total area of beelike structures decreased, and the roughness parameters increased with an increase in chloride salt concentration. Compared to matrix asphalt, the beelike structures in crumb rubber (CR) modified asphalt disperse into finer, speckled black-and-white patterns. The styrene–butadiene–styrene (SBS) modifier forms a stable three-dimensional spatial network structure within the asphalt, diminishing the difference between beelike and non-beelike structures. In the original state, the average roughness (Ra) and root mean square roughness (Rq) of PJ90/CR are 63.0% and 74.0% lower than those of PJ90, respectively. Meanwhile, the Ra and Rq of PJ90/SBS are 42.7% and 46.9% lower than those of PJ90, respectively.

Effect of chlorine substitution on the thermal stability of ferro-pargasite and thermochemical properties of ferro-chloro-hornblende

Abstract Substitution of chlorine for hydroxyls in calcium amphiboles has been widely documented but the effect of this substitution on thermal stability is not known. Experimental reversal data are presented here comparing the upper-thermal stability of amphiboles formed in the ferro-pargasite and ferro-chloro-pargasite bulk compositions. Experiments were made over the range of 550 – 900°C and 0.5 – 3 kbar at oxygen fugacities of log(fO2) of -0.3 to +0.5 relative to Co-CoO. Electron microprobe analysis of amphiboles made from the ferro-pargasite bulk composition were found to be ferro-pargasite, while those made from the ferro-chloro-pargasite bulk composition were low in A-site Na and Cl and were better classified as Cl-bearing ferro-ferri-hornblende. Although the differences between desired and observed amphibole compositions complicate the comparison of their thermal stabilities, it can be deduced that the Cl-bearing amphibole has a steeper dP/dT slope and, above 1 kbar, a lower thermal stability than ferro-pargasite. Thermodynamic analysis of the Cl-bearing amphibole was also done to extract thermochemical data for the Cl end-member amphibole ferro-chloro-hornblende (Ca2(Fe4Al)(AlSi7)O22Cl2 = Fe-Cl-Horn) that are consistent with the thermodynamic database of Holland and Powell (2011). Using an ideal-activity expression and estimated values for the heat capacity (CP = 1.106 + 8.9156 X 10-5(T, K) – 11,218.3/T2 – 5.9548/T0.5; kJ/K·mol) and volume (283.0 ± 1.5 cm3/mole) for Fe-Cl-Horn, the derived values for ΔHf° and S° are -10,842.6 ± 10.3 kJ/mol and 618.8 ± 11.1 J/K·mol, respectively. The implication of this work is that (a) chlorine appears to lower the thermal stability of a given calcium amphibole in contrast to the marked increase in thermal stabilities caused by fluorine, and (b) thermochemical data such as those derived in this study allow absolute concentrations of chloride salts to be calculated in metasomatic paleobrines, as illustrated for the Bamble sector of southern Norway reported in the literature.

Facet-Dependent Selectivity of Rutile IrO2 for Oxygen and Chlorine Evolution Reactions

Water electrolysis is a promising route for sustainable production of hydrogen as an energy storage medium and valuable precursor for industrial chemical syntheses such as ammonia and methanol. Direct electrolysis of seawater circumvents costly desalination and purification steps to reduce the price of renewable hydrogen to achieve cost parity with carbon-intensive steam reforming. However, the significant concentration of chloride salts in seawater poses a challenge to selectivity of seawater electrolysis. In aqueous chloride electrolytes, the chlorine evolution reaction (CER) is kinetically favored over the oxygen evolution reaction (OER). Rutile-type iridium dioxide (IrO2) is a state-of-the-art electrocatalyst for water electrolysis but is also a benchmark chlorine evolution electrocatalyst in the industrial chlor-alkali process. Understanding OER/CER selectivity is needed to make seawater electrolysis a viable energy conversion technology in the future.In this work, we seek to understand the relationship between crystallographic facet and competitive reaction pathway between OER and CER on epitaxial, rutile IrO2 thin films. We investigate facet-dependent OER and CER activity on a series of single-crystalline IrO2 thin films using a rotating disk electrode geometry. The OER/CER selectivity, reaction rate order, and reaction intermediate electroadsorption affinities are explored to add fundamental insight into the reactivity of rutile IrO2 surface. To gain further insight into OER intermediate adsorption affinities, we paired electrochemical measurements with surface-sensitive ambient pressure x-ray photoelectron spectroscopy (AP-XPS). Moving forward, our facet-dependent study of OER/CER selectivity of rutile IrO2 can be used to design selective seawater electrocatalysts for cost-effective and sustainable hydrogen production.

Optimisation of Fungal Laccase Production from Monodictys castaneae

Laccases are copper-containing oxidase enzymes that have broad substrate specificity and applicability in industrial processes. The purpose of this work was to optimise laccase production by a certain endophytic fungus. Monodictys castaneae (Wallr.) Hughes was cultured and incubated using different nutritional and physiological factors affecting laccase production. It was found that the optimum physiological conditions for laccase production were 4 disc inoculum size, a 9-day fermentation period, pH 5, and 28°C. The enzyme was purified using acetone precipitation, gel filtration, and ion-exchange chromatography. The enzyme was identified as a monomeric protein with a molecular mass of 63 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Different concentrations of CuSO4 were used to stimulate laccase production and activity. A 0.15 g/l concentration of CuSO4 was the optimum dosage for laccase activity enhancement. For enzyme-guaiacol interaction, the optimal pH and temperature were 5.4 and 35 °C, respectively. The laccase activity was highly stimulated using 3 mM and 7 mM concentrations of chloride salts of Cd+2, Ca+2, Cr+2 and Fe+3, but the enzyme activity was slightly inhibited by 10 mM concentrations of these metal ions. According to all previous results, Monodictys castaneae showed promising potential as a producer of laccase.

Micro-characterization of the adhesion properties and mechanisms at the asphalt-silica aggregate interface under combined thermal-oxygen aging and chloride salt erosion

In this investigation, various Atomic Force Microscopy (AFM) probes were used to characterize changes in the adhesion properties of aged asphalt under different concentrations of chloride salt. The characterization included analyzing the surface morphology, roughness parameters, height-height correlation function (HHCF), and force-distance curves of the asphalt. Additionally, Molecular Dynamics (MD) simulation was employed to reveal the underlying mechanisms that govern changes in adhesion properties between aged asphalt and aggregate when subjected to chloride salt erosion. Interfacial erosion and internal erosion models were constructed to facilitate a comprehensive analysis from multiple perspectives. The results demonstrate that chloride salts interact with the interface between asphalt and silica aggregates, engaging in competitive adsorption with the asphalt. The strength of this competitive adsorption is influenced by the constituents of the asphalt and the concentration gradient of chloride salts both within and outside the asphalt matrix. Under this concentration gradient, polar components are attracted to the asphalt surface by chloride ions, forming triangular adsorption structures with water molecules and aggregates such as asphaltene. Components with lower polarity exhibit distinct distributions and diffusion states due to variations in molecular weight and spatial configuration. As the concentration of chloride salts increases, the concentration gradient intensifies, resulting in enhanced transformations, migrations, and dissolutions of asphalt components. Consequently, the micro-morphology of the asphalt tends to smoothen, the HHCF undergoes significant modifications, roughness decreases, and the adhesion performance between asphalt and aggregate weakens. Moreover, at higher concentrations, the formation of precipitated chloride salt crystals disrupts the continuity of the asphalt, further compromising interfacial adhesion performance. This study is expected to provide theoretical guidance for the modification of asphalt and the improvement of asphalt pavement lifespan in complex service environments.

Durability and microstructure of cementitious composites under the complex environment: Synergistic effects of nano-SiO2 and polyvinyl alcohol fiber

As the most commonly used construction material for marine buildings, cementitious composites are exposed to a complex environment of coupled action of relative humidity, temperature, and chloride salts erosion, which severely impacts the safety and longevity of marine buildings. The effect of nano-SiO2 dosage on the durability of polyvinyl alcohol fiber-reinforced cementitious composites (PVAF-RCC) for the preparation of marine buildings under the complex environment was investigated in this work. The complex environment with the temperature of 50 °C, relative humidity of 100%, and chloride salt concentration of 5% was simulated by the environment chamber. The cementitious composites exposed to the complex environment for 30 d were tested for anti-permeability, anti-chloride ion penetration, frost resistance, and chloride salt erosion resistance. Furthermore, the pore characteristics of the cementitious composites and the micromorphology of nano-SiO2, matrix, and fibers were characterized and analyzed by the combination of scanning electron microscope and mercury intrusion porosimetry tests. Results revealed that the durability of cementitious composites improved initially and subsequently decreased with rising the dose of nano-SiO2 under the complex environment. PVAF-RCC consisting of 1.5% nano-SiO2 obtained the best durability. As the nano-SiO2 dosage increased, the total porosity and cumulative porosity of PVAF-RCC decreased first and subsequently increased. Nano-SiO2 refined and improved the pore structure of PVAF-RCC and the interface between matrix and PVA fibers through its filling effect and participation in the hydration reaction to generate C-S-H gels with filling effect to convert more harmful and harmful pores into less harmful or harmless pores, thus enhancing the compactness and durability of cementitious composites under the complex environment.

Multi-analytical techniques for characterization of ancient Egyptian pottery objects from Cairo University excavations at Saqqara

Archaeological pottery shows various forms of deterioration and degradation. This research aims to determine the chemical composition and diagnose the damage manifestations of three pottery vessels from the archaeological site of Saqqara. The AutoCAD, digital microscope, X-ray diffraction, polarized microscope, portable X-ray fluorescence, and scanning electron microscopy are utilized to understand the preservation status of pottery vessels. According to the investigation’s findings, the chosen vessels had cracks, accumulated dirt, missing parts, peeling of the slip layer, and black deposits. The X-ray diffraction analysis showed that Albite, Anorthite, Wollastonite, Quartz, Calcite, and Hematite are the primary constituents of the vessels. However, the polarized microscope showed the plagioclase feldspar, indicating that the Nile clay is the source of the raw clay and that the temperature rose above 800 °C. Portable X-ray fluorescence and scanning electron microscopy revealed different concentrations of Si, Fe, and Ca, which are the main pottery components. In addition to the presence of high concentrations of chloride salts. There is no doubt that this will help to preserve the archaeological pottery in future studies.

The Impact of Salinity, Putrescin, and Melatonin Interactions on Green Bean Vegetative Indicators

This study aims to assess the effect of salt stress by using concentrations of sodium chloride (0, 40, 20, 60) mmol. L-1. Putrescine (0.2 and 0.4) mmol. L-1 and Melatonin (0.2, 0.4) mmol. L-1 and their overlap in some physiological and phenotypic traits of a green bean plant. The experiment was carried out using a complete randomized design (CRD) as a two-factor experiment (putrescine and melatonin x sodium chloride salt concentrations). The results were statistically analyzed with 10 replications that included 20 root tips for each treatment, and the averages were compared using the least significant difference at the 0.05 probability. The results showed that the effect of salt stress led to a significant decrease in most of the studied traits, a concentration of 60 mmol. L-1 led to a decrease in the percentage of plant survival by average branch length, number of shoots, dry weight percentage, and chlorophyll content. Also, adding melatonin significantly increased most of the studied traits using concentrations of 0.2 and 0.4 mmol. L-1 compared to adding putrescin (0.2), as the average branch length increased by increase, the number of shoots, the survival rate of plants, the dry weight, and the percentage of chlorophyll. The experiment’s results also showed a significant effect of the interaction between salt stress and melatonin on most of the vegetative growth characteristics of green beans. The effect of putrescine led to a decrease in vegetative indicators due to its high concentration in the medium used in the experiment.

Improving Co(II) separation from Ni(II) by solvent extraction using phosphonium-based ionic liquids

The solvent extraction of Co(II) from its aqueous solutions free of acids or chloride salts at high concentration by the ionic liquids trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylpentyl)phosphinate ([P66614][C272]) and trihexyl(tetradecyl)phosphonium thiocyanate ([P66614][SCN]) was characterised at saturation of the organic phase with Co(II) using toluene as diluent. The ionic liquids’ cation participated in the formation of two ion-pairs in the organic phase, i.e., one with the complex anion containing cobalt, and the other with the cobalt counter anion, thus preserving electroneutrality in both the organic and aqueous phases. This was considered to be an example of bifurcated extraction.UV–visible spectral studies of the intensively blue organic phase after Co(II) extraction demonstrated that the Co(II) coordination sphere geometry in the case of both extractants was tetrahedral. The Co(II) extraction stoichiometry was experimentally determined for the first time by saturating the organic phase with Co(II). The [P66614][C272] to Co(II) stoichiometric mole ratio in the extracted adduct was found to be 2.8:1, suggesting that eight phosphinate anions acted as bridging ligands around three cobalt centres. For the [P66614][SCN], the stoichiometric mole ratio was found to be 2.5:1 with the Co(II)-thiocyanate adduct consisting of two Co(II)-thiocyanate tetrahedra linked by a bridging thiocyanate ion.The Co(II) extraction was enhanced when the aqueous phase contained an anion with high lipophilicity (e.g., nitrate, thiocyanate). [P66614][SCN] did not extract Ni(II) from nitrate or chloride solutions, thus demonstrating its potential for the separation of Co(II) from Ni(II) without requiring the addition of high concentrations of acids or chloride salts to the aqueous phase.

A Non-Contact Method for Detecting and Distinguishing Chloride and Carbonate Salts Based on Dielectric Properties Using a Microstrip Patch Sensor

A non-contact method for detecting salt concentration in water using a microstrip patch sensor is presented in this work. The microstrip patch sensor, which has a low cost and simple build process, consists of a circular split ring resonator (SRR) with a hole drilled through the substrate in the middle area, and a microstrip patch antenna. The sensor was designed and fabricated using a printed circuit board (PCB) technique based on a negative dry film photoresist and photolithography method. It was built on an Arlon DiClad 880 substrate with a thickness of 1.6 mm and a relative permittivity of 2.2. The resonant frequencies (Fr) and reflection coefficients (S11) in the frequency range from 0.5 GHz to 0.8 GHz were recorded for analysis, both through simulation and experiment. The concentration of chloride and carbonate salts was varied from 0 mg/mL to 20 mg/mL in the tests using the sensor. The statistical analyses of S11 and Fr data obtained from measurements of five different salts at seven different concentrations (using the Shapiro–Wilk test, Bartlett test, and Kruskal–Wallis H test) were conducted using R version 4.2.0 to determine the relationship between the individual salts. The experimental results showed that the frequency response and resonance amplitude are functions of the concentration of each salt. The proposed method has the potential to be used for the non-contact measurement of industrial products, food quality, and health in the future.

Influence of mineral composition on nano-interfacial adhesion of asphalt mixtures exposed to chloride salt erosion

As a common pavement deicing salt, sodium chloride has adverse effects on asphalt pavement. In this study, molecular modeling methods were used to analyze the effects of mineral composition and chloride salt erosion on the interfacial adhesion properties of asphalt-aggregate composites. Four representative asphalts (AAA-1, AAK-1, AAM-1, and AAF-1), three representative minerals (α-quartz, calcium carbonate, and alumina), and sodium chloride solutions were selected to model the asphalt-aggregate composites exposed to chloride salt erosion. The effects of asphalt type, mineral composition, salt concentration, and erosion temperature on the interface adhesion of the asphalt mixture were considered. The chloride salt erosion resistance of the four components and asphalt molecules were further analyzed. The simulation results indicate that the effect of erosion temperature on the interfacial adhesion performance is minor. The interfacial adhesion decreased with the increase in chloride salt concentration. Alkaline minerals are more susceptible to chloride salt erosion, followed by neutral and acidic minerals. The adhesion energies of resin and aromatic decreased most significantly in alkaline minerals, followed by neutral minerals, and the least decreased in acidic minerals exposed to chloride salt erosion. Asphalt molecules with more aromatic rings, shorter alkyl side chains, and stronger polarity have strong resistance to chloride salt erosion and can form strong adsorption with the active sites on the mineral surface. However, asphalt molecules with long-chain alkanes, fewer aromatic rings, or longer alkyl side chains are difficult to resist chloride salt erosion.

Differential effects of chloride salts on seed germination and seedling growth of Cistus monspeliensis: Towards revegetation of the Mediterranean salt-contaminated soils

Soil salinity is seriously threatening the Mediterranean basin, negatively affecting crops, and degrading natural habitats. However, limited information is available about chloride (Cl−) toxicity, the most common anion in seawater, on seed germination and seedling growth. In addition, seed emergence under individual and combined chloride salts has seldom been studied. In this research, the individual and combined effects of four chloride salts (KCl, CaCl2, MgCl2, and NaCl) on seed germination and seedling growth of Cistus monspeliensis, a Mediterranean shrub that regenerates through seeds, were investigated. Four concentrations of chloride salts (0, 40, 80, and 120 mM) were used. Germination rate (1/t50) was utilized in a halotime model to quantify the maximum concentration of Cl− (Cl−max) for germination at 20 °C under light. Germination decreased with increasing salt concentrations. The reduction in germination at 120 mM was higher in seeds treated with KCl and MgCl2, compared to the other salts, in both light and dark periods. In addition, the germination reduction at 120 mM was greater in dark periods than in light periods for seeds treated with CaCl2 and mixed salts. Germination velocity (GV) was maintained in all salts and concentrations except CaCl2, which decreased it. The lowest synchrony (0.13 ± 0.03) and the highest uncertainty (2.6 ± 0.25) were found in seeds stressed with 80 mM CaCl2. The mixed salts and NaCl improved GV and germination synchronization indicating that these salts have priming effects in enhancing germination speed in salty soils. The Cl−max value of ca. 491 mM for germination, obtained by treating seeds with different chloride salts, shows that C. monspeliensis can be a useful species for restoring chloride-dominated salty soils.