Common Salt Solution Research Articles

Effects of Hydrostatic Pressure and Cation Type on the Chloride Ion Transport Rate in Marine Concrete: An Experimental Study.

The effect of hydrostatic pressure and cation type on chloride ion transport in marine underwater concrete cannot be ignored. The study of the chloride ion transport behavior of concrete under the effect of hydrostatic pressure and cation type coupling can provide a basis for durability design and the protection of marine concrete. In this work, the chloride ion transport behavior of marine concrete in four common chloride salt solutions under different hydrostatic pressures is studied by a hydrostatic pressure test device developed by the authors. The results show that hydrostatic pressure and its action time significantly influence the chloride ion transport behavior in marine concrete; the higher the hydrostatic pressure of concrete, the faster the chloride ion transport rate. The longer the time, the more chloride ions accumulated in the same position, and the farther the chloride ion transport distance. Cation type has a certain influence on the transport process of chloride ions. Under the same test conditions, the chloride ion transport rate in a divalent cation solution is about 5% higher than that in a monovalent cation solution. The results also show that the chloride ion binding capacity under hydrostatic pressure is only 10~20% of that under natural diffusion. Using the test results, a predictive model of a chloride ion apparent transport coefficient based on the hydrostatic pressure and hydrostatic pressure action time corrected by a cation type influence coefficient is established.

Thermodynamic properties of common salts in aqueous solutions

A relationship between the activity of hydrogen ions and charge activity in an aqueous solution has been developed in a previous study. That study also revealed that the potential energy of an aqueous solution can be obtained by multiplying the charge activity with electrostatic potential of the solution. In this study, negative potential energy equalling Gibbs energy of four common salt (NaCl, KCl, NaNO3 and KNO3) solutions were quantified using the charge activity. Then the entropies of those salt solutions were computed using the Gibbs energy, enthalpy, and the charge activity. Charge activities were computed using the pH of those solutions at room temperature. It was found that potential energy, Gibbs energy, enthalpy and entropy of a solution is related to the charge activity of a solution, not the ionic charge number as previously thought. When the concentrations of NaCl, KCl, NaNO3 and KNO3 increased in single solutions the entropies of those solutions tend to decrease allowing them to achieve orderly states leading the salt particles to crystalise. The findings of this study will lead to better understanding and utilization of thermodynamic properties during crystallization which is vital important in brine recovery.

Effect of molecular dynamics water models on flux, diffusivity, and ion dynamics for polyamide membrane simulations

While molecular dynamics (MD) models for reverse osmosis (RO) and nanofiltration (NF) membranes are useful for studying water filtration processes, the specific water model and force-field parameters have a profound impact on key measures such as flux and diffusivity. Moreover, ensemble related parameters such as temperature and how it is controlled via a thermostat also affect simulation results. To quantify these effects, we investigate the performance of three commonly used water models, SPC/E, TIP3P, and TIP4P, in simulating an NF membrane system at varying temperatures and thermostat settings. All three water models successfully capture the Arrhenius relationship between water diffusivity and temperature as well as the linear relationship between water flux through the membrane and water diffusivity in the membrane. However, SPC/E underpredicts, TIP3P overpredicts, and TIP4P most accurately reproduces the water dynamics, especially water self-diffusivity, compared to experiments. We also investigate the effect of the water model on common salt solutions at various concentrations. TIP4P generally outperforms the other two water models when describing ion diffusivities and water solvation shells around ions. These findings indicate that TIP4P is an appropriate water model to use in polyamide membrane MD simulations.

Designing water vapor fuelled brine-silk cocoon protein bio-battery for a self-lighting kettle and water-vapor panels

Water vapor increases the electrical conductivity of silk cocoons, human hair, jute, and corn silk. This phenomenon is unclear. In the present study, XPS analysis of cocoons showed that water vapor reduces the surface presence of low-energy carbon species (C–C, C–H). In contrast, electron-dense, high-energy carbon species (C–N, C=C, C=O) remained unchanged, possibly enhancing surface charge hopping. While water vapor improves the conduction, the deficiency of charge carrier diminishes the effect. We increase the charge carrier by soaking the cocoon in an aqueous solution of common salt (NaCl) to amplify the current. Salt treatment followed by 2-min exposure to water vapor results in a sharp upward spike in the current (3.6 ± 1.07 mA, n = 12; mean ± SE) from the baseline (0.06 ± 0.02 mA, n = 12). After 1 h, it maintains an average value of 0.39 ± 0.12 mA; n = 12, indicating an upward shift in the baseline. Every time the cocoon charges with water vapor, the next charging cycle initiates after the cocoon dries up. Inspired by the cocoon ecology, we demonstrate an alternating 'water vapor–dry air' cycle for rapid charging and discharging of the cocoon battery. Finally, we designed a prototype of a self-lighting kettle and water–vapor panels for futuristic homes using a 'brine-silk cocoon protein bio-battery,' where moist waste heat generates electricity.

Features of a burning electric arc superimposed on gas discharge with liquid electrolyte cathode

The conditions for burning an electric arc in a discharge plasma with a solution cathode have been studied. Both discharges were connected to the same metal anode. The electric arc burned in the current range of 5–10 A. The discharge current with a solution cathode varied within 8-15 A. In the experiments, aqueous solutions of common salt were used. The specific electrical conductivity of the solutions was 10–15 mS/cm. Spectral investigations of arc plasma radiation and discharge with a solution cathode have been carried out. Calculations of the parameters of the electron gas in the plasma column have been performed.

Retention of β -Carotene from Leafy Vegetables

During the present investigations, effect of table salt on retention of β-carotene from leafy vegetables from Marathwada was studied. Getting vegetables throughout the year is obscure in rain feed area like Marathwada. Retention of nutrition from vegetables is important for health in absence of in adequate preservation techniques. Five different green leafy vegetables which are consumed by the peoples on large scale have been tried during the present piece of work. These vegetables are Spinach (Spinacia oleracea L.), Coriander (Coriandrum sativum L.), fenugreek (Trigonella foenum-graecum L.), Shepu (Anathum graveolens L.) and Cabbage (Brassica oleracea var. capitata L.) which are commonly consumed in Marathwada region. These vegetables were soaked with solution of common Table salt i.e. Sodium Chloride (NaCl2) at different concentrations. After analysis it was noted that in Spinach, Coriander, Trigonella and Anthem. The results obtained during the work clearly indicate that, the common salt can act as excellent preservative for retention of β-carotene from leafy vegetables.

The influence of inorganic electrolyte on the properties of carbon quantum dots in electrochemical exfoliation

Abstract Carbon quantum dots (CQDs) with highly graphitic structure are of great importance for electronic performance in applications of optoelectronics or photocatalysis. A facile method to obtain CQDs is the electrochemical exfoliation of graphitic materials. In our previous work, CQDs have been exfoliated from graphite rods in electrolyte of distilled water, organic and inorganic solutions, and the results show that inorganic electrolyte is the best choice in economy and efficiency. According to previous conclusions, the type of electrolyte has a prominent influence on the property and morphology of CQDs in process of exfoliation. However, to the best our knowledge, the type of inorganic electrolyte on behaviors of CQDs has not been researched and reported. Herein, a series of common inorganic salt solution are used as electrolyte and are compared to each other for the best choice of electrochemical exfoliation. Nitrate solution for electrochemical exfoliation of CQDs is better than any others, not only due to its similar photoluminescence, but also possessing common average size of 3.5 nm, which lead to regular and easily distinguishing morphology in TEM image. The lattice spacing of 0.21 nm observed from HRTEM is indicative of graphitic nanostructure. The blue photoluminescence of as-exfoliated CQDs is relative weak with quantum yield of 5.6%. Thus, we are inclined to believe that its photoluminescence mechanism is attribute to quantum confinement effects of carbon core rather than surface functional groups. It can also be supported by XPS and FT-IR results that only some simple groups (-OH and C=O) were form on surface of CQDs during exfoliation. Therefore, the electrolyte of nitrate shows the best suitability for the electrochemical exfoliation of CQDs. Besides, it can provide a way to tune the size of CQDs by electing different electrolyte.

Flotation kinetics of molybdenite in common sulfate salt solutions

This study investigates the kinetics of molybdenite (MoS2) flotation in sulfate media (Na+, K+, Ca2+ and Mg2+) with a concentration of 10−4–10−2 M. Results indicate that both monovalent and divalent cations inhibit MoS2 flotation. Three flotation models were used to fit the flotation kinetic data. The Gamma model gives the best goodness of fit in terms of RAdj2 (adjusted coefficient of determination) and RMSE (root mean square error), however, fails in predicting MoS2 flotation recovery in MgSO4 solution due to the contradictory to the actual flotation trend. In contrast, the rectangular model fits MoS2 flotation in all the sulfate solutions. The flotation rate constant k values decrease with increasing sulfate concentration, indicating that the increased sulfate concentration reduces MoS2 flotation rate. The lowest k was found in the MgSO4 media, suggesting that MgSO4 is most detrimental to MoS2 flotation recovery. In addition, the R∞ was decreased with increasing sulfate concentration in an order of Mg2+ > Ca2+ > K+ > Na+, with the minimum R∞ being obtained in 10−2 M MgSO4, probably due to the formation and adsorption of hydrophilic Mg(OH)2 onto MoS2 surface.

Natural Fermentation of Orange Sweet Potatoes to Produce Brined Pickle under Different Salt Content

Background and Objective: The lactic acid fermentation without starter addition (natural fermentation) may provide a standardpreservation technique to produce sweet potatoes pickle that can be adopted at the household level. The objective of this study was toinvestigate the potential use of natural fermentation with variants of salt concentration to produce acceptably pickled of orange-fleshedsweet potatoes. Materials and Methods: The cubes were pickled by lactic fermentation by brine the cut and blanched cubes in fiveconcentration level of common salt (NaCl, 1-6%) solutions and incubated for 12 days. Every 2 days, the sample was withdrawn for thevarious analysis, i.e., total acidity pH, total soluble solid, reducing sugar and total lactic acid bacteria. Meanwhile, the sensory was measuredonly for day 12 fermentations. Results: All physicochemical and sensory of pickled were affected by salt concentration during fermentation. Higher salt concentration increased total soluble solid and reducing sugar of the pickle but decreased total acidity and consequently influenced the aroma, color, texture and overall appearance of the pickle. About 5% of salt concentration wasfound to be organoleptically most acceptable (moderately like). Conclusion: The sweet potatoes pickle prepared using 5% of saltconcentration could be a good prospect for commercialization in small-scale industries and could be used to fulfill the growing demands of foods with low sodium content.

Environment-friendly solutions for the disposal of waste generated during drinking water disinfection with electrolytic sodium hypochlorite

The present article is concerned with the problems of recycling and reuse of waste generated in the electrolytic production of sodium hypochlorite at water treatment plants. New engineering solutions aimed at ensuring environmental safety and lack of waste during large-scale production of sodium hypochlorite from aqueous solutions of common table salt are recommended herein.

Role of seed priming in improving seed germination and seedling growth of maize (Zea mays L.) under rain fed condition

Seed priming enhances early seed emergence and proper crop stand establishment which enables the crop to capture more soil moisture, nutrients, and solar radiation. An on-farm experiment was conducted in Okhaldhunga, Nepal to study the effect of six different priming treatments (50 millimoles common salt solution, 200 millimoles urea solution, 1 percent MOP solution, 2.5 times diluted urine, water, and control) on germination and growth of two maize varieties, Manakamana-3 and Nutan-IL60. The experiment was set up in factorial randomized complete block design with three replications. Various germination traits: germination percent, seedling vigour, germination index, mean germination time, and seedling growth traits: shoot length, root length, and dry root weight, were studied. Nitrogen-based (Urea and Urine) priming resulted the most desirable change for the studied traits. Nitrogen-based priming also had significant positive effect on stress tolerance related traits like root length and dry root weight.

Disposal of waste generated during drinking water disinfection with electrolytic sodium hypochlorite

The present article is concerned with the problems of recycling and reuse of waste generated in the electrolytic production of sodium hypochlorite at water treatment plants. New engineering solutions aimed at ensuring environmental safety and lack of waste during large-scale production of sodium hypochlorite from aqueous solutions of common table salt are recommended herein.

Recovery of High Molecular Weight DNA from Old viscera Samples via Two Established Methods for Human Identification: A Comparative Study

At autopsy, in cases of suspected poisoning or drug intoxication, the viscera are mostly preserved in saturated common salt solution for toxicological analysis. However, frequent situation arises where the preserved viscera sample gets questioned for its source of origin and identification of the individual contributing the said viscera becomes important. In such a scenario, to identify the source of viscera, the DNA Profiling technique can be employed. This study aims at recovery of high molecular weight DNA suitable for DNA profiling from a 5-year-old viscera sample through modified validated methods. Approximately 2 g of viscera samples (kidney) were taken for the study and two different established DNA extraction methods were employed for isolating DNA for downstream procedures viz. quantitation of the extracted DNA, the amplification of the desired loci Polymerase chain reaction (PCR) and its subsequent genotyping. The yield of DNA extracted from both the methods was quantitated using real time PCR system and a complete DNA profile was obtained for the purpose of comparison with the biological relatives of the individual.

Thermodynamic analysis of a mechanical vapor recompression evaporation system coupled with crystalization for salt separation

AbstractCurrently, the mechanical vapor recompression (MVR) system is extensively used for single salt separation, but the relevant research on mixed salt system treatment is still in initial stage. As a very common salt solution system, sodium chloride–potassium chloride–water system can be readily found in many processes. It is no doubt of great significance to separate their crystals from the mixed solution in an efficient and environmentally friendly way. Therefore, with the aid of Aspen Plus software, this study aims to design an MVR evaporation system capable of treating sodium chloride–potassium chloride–water system. Subsequently, the analysis about the start‐up schemes and some influencing factors in the steady‐state operation are carried out, so as to provide some guidance and reference for the future technical route to separate mixed salt system with low energy consumption.

ALTERNATIVE CONCEPTIONS OF COMMON SALT HYDROLYSIS AMONG UPPER-SECONDARY-SCHOOL STUDENTS

Reactions in aqueous solutions are an important part of chemistry education. As experience shows, they are particularly difficult for students to understand. Hydrolysis is one such reaction. It occurs in organic and inorganic compounds with either covalent and ionic structures, but salt hydrolysis is a special example. Salt hydrolysis is complex, and to understand it, students must consider the reaction equilibrium, dissociation process, and acid-base properties of reactants and products. Additionally, in the upper-secondary-school curriculum, hydrolysis is described only qualitatively, which can lead students to misinterpret hydrolysis and solution equilibrium. In this study, 235 upper-secondary-school students answered questions about the acidity of common salt solutions and tried to justify their responses by writing appropriate chemical equations. An analysis of the answers revealed the students’ alternative conceptions and misconceptions. The character of the misconceptions showed that they are school-based and largely caused by excessive simplification of the process as well as the usage of inappropriate analogies. Key words: salt hydrolysis, acids and bases, alternative and misconceptions, chemical education research.

Alternative utilization of algal biomass (Ulva sp.) loaded with Zn(II) ions for improving of soil quality

This study focused on the alternative utilization of marine algal biomass (Ulva sp.), first as biosorbent for the removal of Zn(II) ions from aqueous solution and then as fertilizer for the improvement of soil quality, by its supplementation with Zn(II) as essential microelement. The biosorption experiments performed in batch systems at room temperature (22 ± 0.5 °C) showed that maximum removal efficiency of Zn(II) onto marine algae biomass is obtained in an initial solution with pH of 5.5, 8.0 g L−1 biosorbent dose, and 2 h of contact time. Under these conditions, the biosorption capacity reached 29.63 mg Zn(II) g−1 biomass. The desorption experiments have indicated that Zn(II) can be quantitatively released from loaded biomass using solutions of common inorganic salts and suggests the possibility of using Zn(II)-loaded biomass as fertilizer. This possibility was tested using an aric antrosol sample. After 8 weeks of treatment with Zn(II)-loaded biomass, the Zn(II) content in the soil sample increased over four times. Therefore, the marine algae loaded with Zn(II) can be a viable alternative of fertilizers and can be successfully used to increase soil quality.

Determining the Enthalpy of Vaporization of Salt Solutions Using the Cooling Effect of a Bubble Column Evaporator

The enthalpy of vaporization (ΔHvap) of salt solutions is not easily measured, as a certain quantity of pure water has to be evaporated from a solution, at constant composition, and at a fixed temperature and pressure; then the corresponding heat input has to be measured. However, a simple bubble column evaporator (BCE) was used as a novel method that allowed undergraduate students to determine the ΔHvap value of a salt solution within an hour or so, because it only required temperature measurement (at a steady state) of the column solution and the inlet gas flowing into the column. In this article, by way of illustration, the ΔHvap value of a 0.5 M NaCl solution was determined using the BCE process. In this experiment the evaporative cooling effects of the column were also easily demonstrated, as the inlet air at room temperature cooled the column solution to less than 10 °C. The change that students measured directly demonstrated the endothermic process of water vaporization. The role of several basic physical chemistry concepts, such as vapor pressure, phase transition, and enthalpy, involved in this experiment can be reinforced. An unexpected property of some common salt solutions, of bubble coalescence inhibition, was also observed in this experiment.

Salt Solutions in Carbon Nanotubes: The Role of Cation−π Interactions

Understanding the structure of aqueous electrolytes at interfaces is essential for predicting and optimizing device performance for a wide variety of emerging energy and environmental technologies. In this work, we investigate the structure of two common salt solutions, NaCl and KCl, at a hydrophobic interface within narrow carbon nanotubes (CNTs). Using a combination of first-principles and classical molecular dynamics simulations in conjunction with molecular orbital analysis, we find that the solvation structure of the cations in the CNTs can deviate substantially from the conventional weakly interacting hydrophobic picture. Instead, interactions between solvated ions and π orbitals of the CNTs are found to play a critically important role. Specifically, the ion solvation structure is ultimately determined by a complex interplay between cation−π interactions and the intrinsic flexibility of the solvation shell. In the case of K+, these effects result in an unusually strong propensity to partially desol...

Self-assembly of aqueous bilirubin ditaurate, a natural conjugated bile pigment, to contraposing enantiomeric dimers and M(-) and P(+) tetramers and their selective hydrophilic disaggregation by monomers and micelles of bile salts.

The solution behavior of bilirubin ditaurate (BDT), the first naturally occurring conjugated bile pigment to be physically and chemically characterized, was assessed in aqueous solution and in monomeric and micellar solutions of common taurine-conjugated bile salts (BS). Analytical ultracentrifugation revealed that BDT self-associates in monomer-dimer equilibria between 1 and 500 μM, forming limiting tetramers at low millimolar concentrations. Self-association was enthalpically driven with ΔG values of ≈5 kcal/mol, suggesting strong hydrophobic interactions. Added NaCl and decreases in temperature shifted the oligomerization to lower BDT concentrations. On the basis of circular dichroism spectra and the limiting size of the self-aggregates, we infer that the tetramers are composed of 2P(+) and 2M(-) enantiomeric BDT pairs in "ridge-tile" conformations interacting in a "double-bookend" structure. With added monomeric BS, blue shifts in the UV-vis spectra and tight isosbestic points revealed that BDT/BS heterodimers form, followed by BDT "decorating" BS micelles mostly via hydrophilic interactions. Conformational enantiomerism, fluorescence intensities, and anisotropy, as well as resistance of the hybrid particles to disaggregation in 6 M urea, suggested that two or three hydrogen-bonding sites bound BDT monomers to the hydroxyl groups of BS, possibly via pyrrole-π-orbital-OH interactions. BDT stabilized these interactions by enveloping the BS in its "ridge-tile" pincers with variable strain that maximized van der Waals interactions. Possibly because the BDT molecule becomes highly strained with BS subtending a 7β-hydroxyl group, BDT became totally resistant to oxidation in air. This work predicts that, because of BS dissolution of the BDT self-aggregates, BS/bilirubin hybrid particles, which are stabilized hydrophilically, are likely to be the dominant mode of transport for all conjugated bilirubins in bile.

Studies on Bubble Column Evaporation in Various Salt Solutions

The physical properties of concentrated salt solutions are an important aspect of many industrial processes. The effects of different salts on the inhibition of bubble coalescence have raised some unexpected observations, because some salts inhibit coalescence while others have no effect over a wide concentration range. Fortunately, many common salts inhibit bubble coalescence and although the mechanism is not fully understood, this effect allows the construction of bubble column evaporators (BCEs) for the efficient transfer of both vapor and heat. In this study the BCE process has been used under steady state conditions to determine the latent heat (enthalpy) of vaporization (ΔH vap) of concentrated solutions of several common salts. In addition, it was found that under non-steady state conditions using high inlet gas temperatures, the rate of vapor transfer, and hence thermal desalination, could be increased using the BCE process. Some new observations on the fundamental mechanism of the bubble coalescence phenomenon are also reported.