Addition Of NaCl Research Articles

Produção e qualidade da couve folha hidropônica sob estresse salino e concentrações de KNO3

ABSTRACT Potassium is a nutrient with the potential to increase plant tolerance to salt stress. The aim of this study was to evaluate the production and quality of kale subjected to salt stress and potassium concentrations in a protected environment. The experimental design was in split plots, with plots composed of five nutrient solutions (control treatment, S1 - standard nutrient solution prepared in low-salinity water, 0.5 dS m-1 (500 mg L-1 of KNO3), and four nutrient solutions prepared in brackish waters (3.5 dS m-1) containing four concentrations of KNO3 (S2 - 500 mg L-1, S3 - 625 mg L-1, S4 - 750 mg L-1, S5 - 1,000 mg L-1), and subplots represented by two leaf kale cultivars (Manteiga and Manteiga da Geórgia). Leaf production variables and post-harvest physical and chemical qualities were evaluated. The saline nutrient solution with the addition of NaCl (S2) reduced production but did not reduce the post-harvest quality of kale. The extra addition of KNO3 at 25% (S3) was efficient in reducing the deleterious effects of salt stress on the variables leaf length, leaf area, leaf production, and number of bunches. The cv. Manteiga da Geórgia was more tolerant to salt stress than the cv. Manteiga.

Effect of Salinity on the Growth and Biochemical Profile of Hedypnois cretica and Plantago coronopus Plants in Relation to the Cropping System and Growth Environment

The aim of the present work is to study the impact of salinity (i.e., 2 dS/m without addition of NaCl (control); 5 dS/m (EC-5); and 10 dS/m (EC-10) with the addition of 30 and 80 mM NaCl, respectively) on yield, organoleptic quality and the content of antioxidant compounds in Plantago coronopus and Hedypnois cretica plants in relation to different cropping systems and environmental conditions during growth (i.e., pots or floating hydroponics systems in the greenhouse and pots in the field (GPs, GH and FPs, respectively)). Almost all the growth parameters of the H. cretica plants in the greenhouse were impaired by both moderate (EC-5) and high (EC-10) salinity levels, especially in the floating hydroponics system, where, compared to EC-2, a reduction was observed of 33% in EC-5 and 76% in EC-10 in leaf area and of 24% and 75%, respectively, in fresh weight. On the contrary, the growth of the P. coronopus plants was negatively affected by salinity only in the GP system. However, salinity had no effect on most growth characteristics of both species grown in the field, suggesting a strong environmental effect on the impact of salinity in the tested species. On the other hand, the content of pigments, proline and total phenolics in the P. coronopus leaves, as well as their antioxidant capacity, were not affected by salinity in most cases, whereas in H. cretica the salinity effect was significant even at moderate levels (EC-5) in relation to the cropping system and growth environment. Moreover, both salinity levels reduced the nitrate content of P. coronopus plants in all cases (up to 61% in GP plants at EC-10) and of H. cretica GH plants (up to 67% in EC-10). Finally, regardless of the salinity level, the field-grown plants of both species showed a considerably higher content of total phenolics (by 59% in H. cretica and 58% in P. coronopus) and antioxidant activity (by 63% in H. cretica and 53% in P. coronopus, FRAP values), compared to the greenhouse ones. In conclusion, our results indicate that the tested combinations of cropping systems and growth environments could be used as an eco-friendly and sustainable agronomic tool to mitigate the negative effects of salinity and to regulate the organoleptic and biochemical properties of the tested species, allowing small-scale farmers in the affected areas to cope with the ongoing climate change and the environmental pressures they currently face through the exploitation of alternative/underexploited species of high added value.

Emulsification in nearly Newtonian and non-Newtonian media of wormlike micelles

Emulsification experiments with four silicone oils, having viscosities ranging from 0.01 to 30 Pa.s, were conducted in two types of media: nearly Newtonian polyvinyl alcohol (PVA) solutions and non-Newtonian mixtures induced by worm-like micelles in solutions of sodium laureth sulfate and cocoamidopropyl betaine (BS) with NaCl. The increased viscosity of BS solutions upon the addition of NaCl did not significantly affect the drop size in the formed emulsions. In contrast, the increased viscosity of solutions with higher PVA concentrations significantly reduced the drop sizes for all silicone oils. A theoretical expression predicting the maximum drop size in both types of media (nearly Newtonian and non-Newtonian) was derived and validated against experimental data. The expression accounts for shear-thinning behavior in both the aqueous and oil phases. Interfacial stress dominates the breakage of less viscous oils, while viscous stress inside the breaking drop plays a leading role for more viscous oils. The formation of emulsions with similar sizes in non-Newtonian solutions of BS with different NaCl concentrations was explained by their strongly shear-thinning behavior, which leads to nearly similar viscosity at high shear rates, despite their zero-shear viscosities differing by more than two orders of magnitude.

Locally Synthesized Zwitterionic Surfactants as EOR Chemicals in Sandstone and Carbonate.

Zwitterionic surfactants are found to be highly effective in reducing the IFT and changing the wettability. This work studied the solubility and wettability alteration performance of locally synthesized zwitterionic surfactants in Berea sandstone and Indiana limestone. Contact angle measurements were conducted to study the wettability under different conditions. SEM images and TGA results were combined to reflect on the wettability alteration mechanism. The zeta potential test was adopted to study the surface charge of the Indian limestone powder. Results showed that five of the six surfactants dissolved in deionized water to form 1.0 wt % solution, indicating efficient solubility for EOR purposes. Although its wettability alteration performance on oil-aged Berea sandstone is weak to moderate, the performance of ZW6 on Indiana limestone is excellent. ZW6 can change the strongly oil-wet (162°) rock back to water-wet (62.9°) conditions. Increasing its concentration from 0.01 to 0.5 wt % continuously enhanced the performance. The addition of NaCl to 150000 ppm did not affect the wettability alteration. However, the addition of CaCl2 largely suppressed the wettability alteration, while Na2SO4 and MgCl2 both enhanced the performance. With the same headgroup, a more hydrophobic tail group impairs the wettability alteration. The quite different wettability alteration performance of MgCl2 and CaCl2 cases (which had approximately the same amount of calcite dissolution), and the comparable wettability alteration performance of Na2SO4 and MgCl2 (which had very different calcite dissolution amounts) indicate that calcite dissolution is unrelated to wettability alteration.

Synchronously improving intracellular electron transfer in electron-donating bacteria and electron-accepting methanogens for facilitating direct interspecies electron transfer during anaerobic digestion of kitchen wastes

Two major issues generally limit the effectiveness of direct interspecies electron transfer (DIET) during anaerobic digestion: 1) lack of essential electrical connection component, electrically conductive pili (e-pili) or multi-heme c-type cytochrome (MHC); 2) the thermodynamic limitations of combining electrons with protons for reducing carbon dioxide to methane. To address both issues, a strategy for facilitating DIET via combining ethanol-type fermentation pretreatment (EFP) with NaCl addition during anaerobic digestion of kitchen wastes was proposed. Combining EFP with NaCl addition dramatically increased methane yield rates (531.3 ± 11.4 vs 410.5 ± 8.7 mL/gVSadded/d) and efficiencies of conversion of organic substrates to methane (571.2 ± 13.8 vs 488.7 ± 11.7 mL/gVSremoval). The increased performances by combining EFP with NaCl addition were higher than that by independent EFP or NaCl addition. Paludibacter sp., Petrimonas sp. and Syntrophomonas wolfei were the predominant and metabolically active electron-donating bacteria, and their expression of genes for e-pili/MHCs by combining EFP with NaCl addition was higher than that by independent EFP or NaCl addition. Methanothrix soehngenii and Methanoculleus bourgensis were the predominant and metabolically active electron-accepting methanogens, and their expression of genes for carbon dioxide reduction pathway for methanogenesis by combining EFP with NaCl addition was higher than that by independent EFP or NaCl addition. In addition, EFP specifically increased the transcript abundance of genes for NAD+/NADH transformation closely associated with the formation of e-pili/MHCs, while NaCl addition specifically increased the transcript abundance of genes for coenzyme F420/F420H2 transformation known to participate in reduction of carbon dioxide to methane.

Mechanism governing textural changes of low-moisture tofu induced by NaCl addition in soymilk

This study aimed to investigate the impact of NaCl (0 – 1 g/100 mL) on the textural properties of calcium-coagulated low-moisture tofu (LM-tofu) and explore the underlying mechanism governing the NaCl-induced changes of relevant properties. Increasing the NaCl level in soymilk led to higher yield (134.2 – 192.2 g/100 g soybean) of LM-tofu with higher water content (69.2 – 76.7%), reduced protein (11.3 – 16.3%) and lipid (6.87 – 9.22%) levels, and enhanced water binding capacity (WBC, 4.26 – 6.78 g H2O/g protein) and water holding capacity (WHC, 3.63 – 5.49 g H2O/g protein) of soy proteins. Although NaCl had a minor effect on the interactions between proteins and mobilized water or tightly bound water, it significantly improved the proteins' ability to bind loosely bound water due to electrostatic interactions between the charged groups of proteins and hydrated Cl- and Na+ ions. Moreover, the amounts of loosely bound water were highly correlated with both WBC and WHC of proteins (correlation coefficient: 0.999 and 0.995, respectively). The enhanced water binding capacity of proteins for loosely bound water due to an increased salt level resulted in LM-tofu with a less dense protein network structure, weaker strength and reduced deformation ability. This study provides insights for the development of high-calcium, soy protein-based foods to meet the growing demands for healthy and convenient plant-based snacks or meals.

Excellent properties of NaF and NaBr induced DNA/gold nanoparticle conjugation system: Better stability, shorter modified time, and higher loading capacity

The functionalization of gold nanoparticle (AuNP) is the key procedure for the biochemical and biomedical application. The conventional salt-aging method requires the stepwise additions of NaCl and excessive thiolated DNA, mainly due to the poor tolerance of the DNA/AuNP mixture toward NaCl. Herein, we found that NaF is capable of improving the stability for the modification of AuNP with different bases of DNA sequences (poly A/T/C/G), and allows for adding up with a high concentration of 200 mM at one time, which greatly reduces the total modification time to 0.5–1 h. Intriguingly, the introduction of NaBr effectively increases the DNA loading capacity. Besides the advantages of NaF and NaBr, the modification performance is improved via the introduction of the oligo A/T spacer for the G-rich DNA sequences. Furthermore, this method shows the superiority to another two methods (pH 3-based and salt-aging) in terms of the loading capacity or sequence components.

Assessment of salt-free electrodialysis metathesis: A novel process for brine management in brackish water desalination using monovalent selective ion exchange membranes

Since reverse osmosis (RO) is often limited to a water recovery of 70–85 %, implementing a secondary process like electrodialysis metathesis (EDM) to treat concentrate can increase system water recovery. This study explores salt-free electrodialysis metathesis (SF-EDM) as an alternative to conventional EDM to investigate its performance in the zero discharge desalination (ZDD) process. SF-EDM utilizes monovalent-selective ion exchange membranes, eliminating the need for sodium chloride (NaCl) as a substitution solution. This approach generates one diluate stream and two highly soluble concentrate streams enriched in calcium and sulfate, respectively. In this article, a series of lab-scale tests based on synthetic and real RO concentrate were performed to investigate how SF-EDM performs operating at high water recovery with a feedwater with high scaling potential. We critically analyze the performance in terms of salinity reduction, selectivity, and energy consumption. Results of the study show that without the addition of NaCl, the process was able to selectively separate sulfate and calcium into two concentrate streams achieve a salinity reduction of 93 % and a total system water recovery (RO and SF-EDM) of 90 %. A technoeconomic analysis found SF-EDM to be 80 % of the cost of conventional EDM making it a competitive technology for brackish water RO concentrate management.

Enhancing Electrospinnability of Chitosan Membranes in Low-Humidity Environments by Sodium Chloride Addition.

The electrospinning of pure chitosan nanofibers is highly sensitive to environmental humidity, which limits their production consistency and applicability. This study investigates the addition of sodium chloride (NaCl) to chitosan solutions to enhance spinnability and mitigate the effigurefects of low humidity. NaCl was incorporated into the electrospun chitosan solution, leading to increased conductivity and decreased viscosity. These modifications improved the electrospinning process. Comparative analyses between chitosan membranes (CM) and sodium-chloride-added chitosan membranes (SCM) revealed no significant differences in chemical structure, mechanical strength, or in vitro cell proliferation. This indicates that the addition of 1% (w/v) NaCl does not adversely affect the fundamental properties of the chitosan membranes. The findings demonstrate that NaCl addition is a viable strategy for producing electrospun chitosan nanofibers in low-humidity environments, maintaining their physicochemical properties while enhancing spinnability.

The Impact of Adding a Cationic Metal Salt and Curcumin to Monoammonium Glycyrrhizic Acid on Its Solubilizing Capacity and Gelation.

Monoammonium glycyrrhizic acid (MAG), a glycyrrhizic acid monoammonium salt, is a naturally derived low-molecular-weight gelling agent with surface-active properties. It has the capacity to individually facilitate the preparation of gel-solubilized drugs. As MAG is an anionic surfactant with carboxyl groups, the addition of counterions may affect micelle formation and gelation. In this study, the solubilization and gelling properties of MAG were investigated following the addition of metal salts (NaCl and KCl). The addition of metal salts resulted in a decrease in the critical micelle concentration and an increase in gel hardness. Supersaturation of curcumin (CUR) was maintained by the addition of metal salts because of increased micelle number and viscosity. When the gel hardness was compared between formulations with and without CUR, a significant reduction in hardness was observed with the solubilization of CUR. The addition of KCl prevented the decrease in the hardness of gels containing CUR compared to the addition of NaCl. Put together, the addition of metal salts had a noteworthy impact on micelle and gel formation of MAG. In particular, the addition of KCl was more effective in the preparation of gel-solubilized CUR.

Natural deep eutectic solvent-based dispersive liquid-liquid microextraction of pesticides in drinking waters combined with GC-MS/MS detection

The current research aims to develop a new analytical method applying a dispersive liquid-liquid microextraction (DLLME) assisted by vortex and using an environmentally friendly extractant for the preconcentration of organochlorine and organophosphorus pesticides followed by gas chromatography-tandem mass spectrometry (GC-MS/MS) analysis. The extractant (i.e., natural deep eutectic solvent (NADES)) is safe, cheap, biodegradable and can be prepared by simply mixing DL-menthol and decanoic acid (molar ratio 2:1). The main experimental factors affecting the extraction of all analytes evaluated (19 organochlorine and organophosphorus pesticides) have been optimised using a multivariate analysis consisting in two steps: a Plackett-Burman design followed by a central composite design (CCD). Seven experimental factors have been evaluated: (i) sample volume; (ii) NADES volume; (iii) sample pH; (iv) extraction time; (v) centrifugation time; (vi) centrifugation speed; and (vii) ionic strength (NaCl %, w v−1). For the significant variables, the optimum values were 10 mL sample and 45 μL NADES. No pH adjustment as well as addition of NaCl were needed. The other variables were set at 3 min extraction time, 5 min centrifugation time and 900×g centrifugation speed, respectively. Under the optimised extraction conditions, the limit of quantification (LOQ) values ranged between 0.2 and 78 ng L−1 for all analysed pesticides. Furthermore, the proposed analytical method has been successfully applied to drinking water (bottled spring water). The recovery study (n = 3) has been evaluated at 0.1, 1.0 and 5.0 μg L−1 spiking levels, obtaining relative recovery values within the range of 70 % and 117 % and RSD values between 1 % and 20 % for all the analytes studied, except for p,p-DDT (56–77 % in high conductivity water samples).

Effect of particle size, water saturation, inorganic salt and methane on the phase equilibrium of CO2 hydrates in sediments

Understanding the thermal stability of gas hydrate in complex marine geological environment is of importance to hydrate-based carbon sequestration. In this work, the factors affecting the equilibrium of CO2 hydrate in ocean sediments, including quartz sands, inorganic salts and gas impurities were quantitatively measured in a temperature range from 273 to 283 K and a phase equilibrium model of hydrate was established. To reveal the distribution in pore structure, the micro-morphologies of hydrate-bearing sediments were measured by cryo-SEM. Results showed that reduction of initial water saturation, addition of NaCl and CH4 were found to have inhibitory effect on CO2 hydrate equilibrium. Initial water saturation reduced the equilibrium temperature by the capillary pressure, but only 0.3–0.7 K temperature depression was observed as the water saturation reduced to 5 %. About 5.7 K in the average temperature depression was found by the addition of 10 wt% NaCl and 24 mol% CH4. NaCl and CH4 influenced the hydrate equilibrium by changing the water activity and chemical potential of hydrate water lattice. SEM images showed that the hydrate formed in pores of quartz sand had porous surface and coated the sand particles like a layer of cells which are 5–20 μm in diameter, suggesting the hydrate layer exists between the liquid and gas phase. Based on the van der Waals-Platteeuw model, a hydrate equilibrium model was developed. The model provided a good prediction of the hydrate equilibrium in the presence of quartz sand, NaCl and CH4 with an averaged deviation of ±4.2 %, which had the potential to be applicated in more complexed ocean sedimentary environment.

Experimental and molecular dynamics simulation of the synergistic mechanism of short-chain fluorocarbon surfactant and electrolyte on inhibiting coal dust pollution

This paper investigated the synergistic mechanism of short-chain fluorocarbon surfactant and electrolyte on inhibiting coal dust pollution via the experimental and molecular dynamics simulations Findings illustrated that the synergistic application of short-chain fluorocarbon and electrolyte achieves better dust suppression performance when compares with the individual application of FS-50 and FS-3100, the maximum suppression rates for FS-50 and FS-3100 after the addition of electrolytes are 94.48 % and 93.94 %, respectively. The addition of electrolyte reduces the diffusion coefficient of suppressants, and its effect on FS-3100 is much higher than on FS-50. The maximum particle size achieved by FS-50 reaches 304–344 μm, while only 238–269 μm and 269–306 μm are acquired by FS-3100. The smaller negative potential and the larger difference in EPE indicate that the addition of NaCl promotes the adsorption of H2O molecules by surfactants. Compared to FS-3100, FS-50 has a lower negative potential and a larger EPE difference, suggesting that FS-50 exhibits stronger reactivity and better ability of absorb ion hydrates and H2O molecules, and hence has superior agglomeration effect. The addition of NaCl also promotes the generation of more sodium hydrate ions and hydrated chloride ions, which enhances the ability of FS-3100 to absorb H2O. Compares with FS-50, due to special curved spatial configuration and the synergistic effect with electrolytes, FS-3100 could restrict the desorption of large numbers of H2O molecules more effectively, and therefore exhibiting better wettability.

Effects of additives (NaCl, citric acid, and ethanol) on the cooking quality and sensory quality of vermicelli produced from freeze–thaw‐dehydrated whole potato powder

SummaryTo conform to the trend of whole‐food diets in recent years, whole potato powder has been used for the processing of extruded vermicelli. The effects of different additives, such as NaCl, citric acid and ethanol, on the cooking quality and sensory quality of whole potato vermicelli obtained via twin‐screw extrusion were investigated. The colour, gelatinisation properties, water absorption, cooking loss, texture profile analysis, scanning electron microscopy analysis and correlation analysis of the whole potato vermicelli were determined and discussed. The brightness of the whole potato vermicelli increased from 52.0 to 55.4 at 1% NaCl addition and increased from 52.0 to 54.9 at 0.8% citric acid addition, and the water absorption of the whole potato vermicelli increased from 83.1% to 159.1% at 0.4% citric acid addition and increased from 83.1% to 258.9% at 8% ethanol addition. The cooking loss of the whole potato vermicelli decreased from 5.3% to 5.1% at 8% ethanol addition, indicating that ethanol could improve the cooking quality of whole potato vermicelli. The texture properties of the whole potato vermicelli decreased with the addition of ethanol, and the ΔH of the whole potato vermicelli decreased from 3.7 to 1.8 J g−1 at 0.8% citric acid addition and decreased from 3.7 to 1.5 J g−1 at 8% ethanol addition, respectively. Moreover, the addition of ethanol was negatively correlated with the max force, break distance, stretching work, hardness, adhesiveness and chewiness of the whole potato vermicelli. The addition of NaCl was positively correlated with the peak gelatinisation temperature. All three additives affected the microstructure of the whole potato vermicelli, including roughening the cross section and increasing the number of pores. In this study, NaCl improved the gelatinisation properties of whole potato vermicelli, citric acid and ethanol improved the water absorption of the whole potato vermicelli, and citric acid improved the anti‐browning effects of the whole potato vermicelli.

Hydrodynamic Properties and LCST Behavior of Six-Armed Star-Shaped Polymers with Arms of a Diblock Copolymer of Poly-2-Ethyl-2-Oxazine and Poly-2-Isopropyl-2-Oxazine

Star-shaped six-arm polymers with arms of the block copolymers of poly-2-ethyl-2-oxazine and poly-2-isopropyl-2-oxazine were synthesized. The branching center was hexaase[26]cyclophane. The prepared samples differed in the order of block attachment to the core. Molar masses of the two samples were 14200 and 21500 g⋅mol−1. The fractions of poly-2-ethyl-2-oxazine monomers in the arms were 61 and 65%, respectively. It was shown that the arms were strongly folded. Water-salt solutions of the star-shaped block copolymers exhibited thermoresponsiveness. The difference in the phase separation temperatures for the studied samples was caused by the differences in their molar masses and the different contents of poly-2-ethyl- and poly-2-isopropyl-2-oxazine blocks. The concentration dependences of the phase separation temperatures for the synthesized star-shaped copolymers coincided with those for the arms, despite the fact that the molecular masses of the stars and their arms differed by factor of near 6. The addition of NaCl to the aqueous of solutions of the star copolymers did not lead to significant changes in their characteristics. No influence of the order of the block attachment to the core on the molecule conformation and on the thermoresponsive behavior was found.

Effects of Dye Addition on the Rheological Properties of Aqueous Polymer Solutions.

In many commercial applications, polymer-dye interactions are frequently encountered from food to wastewater treatment, and while shear rheology has been well characterized, the extensional properties are not well known. The extensional viscosity ηE and relaxation time λE are the extensional rheological parameters that provide valuable insights into how aqueous polymers respond during deformation, and this study investigated the effect of dyes on the extensional rheology of three different aqueous polymer solutions (e.g., anionic, cationic, and neutral) paired with two different dye salts (e.g., anionic and cationic) using drop pinch-off experiments. We have found that the influence of dyes on the pinch-off dynamics is complex but generally leads to a decrease in, for example, the apparent extensional relaxation time. We have utilized the dripping-onto-substrate method to probe the uniaxial deformation of widely used polymers such as xanthan gum (XG), poly(diallyldimethylammonium chloride) (PDADMAC), and poly(ethylene oxide) (PEO) as the anionic, cationic, and neutral polymers, respectively, paired with either fluorescein (Fl) or methylene blue (MB) as the anionic and cationic dyes, respectively. Polymer-dye pairs with opposite charges (e.g., XG-MB and PDADMAC-Fl) displayed a pronounced decrease in pinch-off times, but even PEO, which is a neutral polymer, resulted in decreased pinch-off times, which was restored by the addition of NaCl. The pinch-off times for the Boger fluid (mixture of poly(ethylene glycol) and PEO), however, were surprisingly uninfluenced by dyes. These results showed that not only did the small addition of dyes strongly decrease the polymer relaxation times, but the relative importance of the dye salts on the polymer pinch-off dynamics was also different from that of pure salts such as NaCl.

THE EFFECT OF NACL ADDITION TO TiO2/NiSe/NC PHOTOCATALYTIC FOR HYDROGEN GAS PRODUCTION

The widespread utilization of fossil fuel has resulted in fuel scarcity due to population growth and increased industrialization, driving the evolution of new renewable energy sources (NRE). Alternatively, hydrogen production through solar water splitting and TiO2 as a potential photocatalyst can be developed due to its good stability, environmental friendliness, and economic viability. However, TiO2 has the disadvantage of a wide bandgap that requires high energy and fast recombination. Therefore, in this research, TiO2/NiSe (TN) was synthesized with N doped carbon dopant modified with NaCl as a photocatalyst material through a solvothermal method. The characterized material using XRD, SEM, UV-DRS, BET, and FTIR. Photocatalytic activity tests were conducted to determine hydrogen production using an MQ8 sensor integrated with an Arduino microcontroller system. The synthesized materials are TN, TNC-0, and TNC-10. The addition of NaCl in carbon doped nitrogen materials of photocatalyst TNC-10 shows a reduction of the bandgap that is the lowest bandgap value obtained was 3.09eV. The photocatalytic activity test results showed a hydrogen production of 120 ppm for TNC-10, which is six-times higher compared to bare TiO2 as a photocatalyst. The increase in hydrogen gas production is due to the addition of NaCl to NC, which can enhance the photocatalytic activity and hydrogen adsorption on the catalyst surface during hydrogen production.

The effect of sodium chloride on the charge state of soot particles in a laminar diffusion flame

This study investigates the effect of sodium chloride on the charge state of soot nanoparticles formed in a laminar diffusion flame by measuring the soot particle size distribution, average charge per particle, and charge fraction at various heights within the flame. The well-studied Santoro burner with methane as the fuel (at 0.35 L/min) and co-flow air (at 70 L/min) was used, which produced a stable laminar diffusion flame with flame height of 61 mm. Samples of soot nanoparticles were extracted via a 0.3 mm orifice in a 3-mm stainless steel tubular probe at various heights above the burner and were immediately diluted by a factor of a few thousand for aerosol measurement. The effect of sodium chloride on a methane flame was investigated by comparing the experimentally measured data for methane-only and methane-NaCl flames. The addition of NaCl particles to the laminar diffusion flame did not have a significant effect on the particles in the nucleation region of the flame. The majority of the incipient soot particles in both flames are uncharged, and their sizes are nearly the same, with diameters of approximately 5 nm or less. However, the size of soot particles differs by approximately 10 % to 25 % between methane-only and methane-NaCl flames in the coagulation-dominated region of the flame. The net charge on soot particles within the coagulation region of the methane-only flames is negative, while it is positive with NaCl addition. The fraction of charged particles and ion concentration decreases with NaCl addition within the coagulation region. The study indicates that the smaller particle size observed in methane-NaCl flames may be attributed to reduced coagulation via altered particle charge states. These factors could be the major contributor to the variations in soot formation between methane-only and methane-NaCl flames. Novelty and Significance StatementThis research addresses a notable knowledge gap concerning the influence of NaCl, a prevalent component of hydraulic fracturing fluids, on soot particle behaviour in flames. By explaining the impact of NaCl on soot formation and charge states, the findings contribute to a deeper understanding of combustion processes in environments influenced by hydraulic fracturing operations, thereby informing strategies for reducing emissions and improving environmental sustainability in energy production. Overall, this article represents a significant advancement in the field of combustion science, with implications for environmental stewardship in energy production.This study provides valuable insights into how the introduction of NaCl alters the electrostatic properties of soot particles. This investigation expands upon existing knowledge by shedding light on the intricate mechanisms underlying soot formation and evolution in the presence of NaCl, elucidating its potential implications for combustion processes involving fossil fuels and industrial flaring.

Rheological and tribological properties of xanthan gum-fucoidan mixture: Effect of NaCl, KCl, and CaCl2

This study endeavored to investigate the effects of salts (NaCl, KCl, and CaCl2) on the rheological and tribological properties of xanthan gum (XG)-fucoidan mixtures. With increasing salt concentrations, the intrinsic viscosity (56.1–30.9 dL/g) of mixtures decreased, with pronouncedly lower values (30.9–35.8 dL/g) observed with CaCl2 addition compared to monovalent salts addition (36.4–46.6 dL/g). This indicates a contraction of hydrodynamic size of the polymers due to the charge screening effect of cations and the formation of a more compact conformation in the presence of CaCl2 than with either NaCl or KCl addition. FTIR analysis revealed changes in the interaction between the two polymers in the presence of each salt. All samples exhibited shear-thinning behavior, and their thixotropic behavior increased as the salt concentration increased. The apparent viscosity and viscoelastic moduli decreased in the presence of monovalent salts but were increased in the presence of CaCl2. This was attributed to the crosslinking effect of Ca2+; Na+ and K+ did not induce crosslinking. In addition, the friction coefficient (μ) of mixtures containing salts reached the maximum at a lower entrainment speed (0.08–0.17 mm·s−1) than that without salt (1.54 mm·s−1), and the mixtures containing salts exhibited lower maximum μ values (0.28–0.62) compared to that without salt (0.83), indicating an improvement in the lubricant properties of XG-fucoidan mixtures. Our findings may help broaden the application of fucoidan in the food industry.

Nanogel particles formed from ethanol-treated whey proteins: Effect of heating, pH and NaCl on their stability.

Whey protein particles have gained significant attention for their ability to enhance the functional properties of foods as they can be used for emulsions and foams stabilization or fat substitution. This study explores the ability of whey protein nanogel particles formed in the presence of ethanol (30–70 % w/w) by controlling pH and ionic strength, to retain their morphological properties after ethanol removal. The stability of the produced nanogel particles after the removal of ethanol was investigated under various conditions, including heat treatment (90 °C, 20 min), pH modification (4−7), and the addition of NaCl (50–300 mM). Morphological analysis was conducted using confocal laser scanning microscopy, laser diffraction analysis, and scanning electron microscopy. The results showed that the exclusion of ethanol resulted in the formation of spherical-like nanogel particles with different sizes ranging from 100 to 200 nm in diameter. The pH of the solution affected the stability of the ethanol-free particles, leading to aggregation when the net charge of the protein approached zero. However, no aggregation phenomena were observed away from the isoelectric point. High concentrations of NaCl led to extensive aggregation, but no substantial changes were found upon heating. The production of nanogel particles is a promising advance with potential for a wide range of food applications.