Addition Of NaCl Research Articles

Biodegradable Solid Polymer Electrolytes from the Discarded Cataractous Eye Protein Isolate.

The protein extracted from the discarded eye lenses postcataract surgery, referred to as the cataractous eye protein isolate (CEPI), is employed as a polymer matrix for the construction of solid polymer electrolyte species (SPEs). SPEs are expected to be inexpensive, conductive, and mechanically stable in order to be economically and commercially viable. Environmentally, these materials should be biodegradable and nontoxic. Taking these factors into account, we investigated the possibility of using a discarded protein as a polymer matrix for SPEs. Natural compounds sorbitol and sinapic acid (SA) are used as the plasticizer and cross-linker, respectively, to tune the mechanical as well as electrochemical properties. The specific material formed is demonstrated to have high ionic conductivity ranging from ∼2 × 10-2 to ∼8 × 10-2 S cm-1. Without the addition of any salt, the ionic conductivity of sorbitol-plasticized non-cross-linked CEPI is ∼7.5 × 10-2 S cm-1. Upon the addition of NaCl, the conductivity is enhanced to ∼8 × 10-1 S cm-1. This study shows the possibility of utilizing a discarded protein CEPI as an alternative polymer matrix with further potential for the construction of tunable, flexible, recyclable, biocompatible, and biodegradable SPEs for flexible green electronics and biological devices.

The effects of NaCl addition on the particle-bubble interactions of galena in the presence of xanthate

This work investigated the effects of NaCl addition on galena flotation in the presence of xanthate. The micro-flotation experiments were performed using NaCl solutions which also included xanthate, at pH 9 (±0.1). Our results indicated that galena recovery improved for higher NaCl as well as higher xanthate concentrations.A pH-dependent chemisorption model for the galena surface, with the addition of xanthate adsorption was calibrated using measured zeta potential values. We propose that xanthate adsorption on galena can take place via two separate mechanisms. The first mechanism involves direct xanthate chemisorption to specific surface sites. The second mechanism involves lead/xanthate complexes formed in the bulk solution. These lead/xanthate complexes attach on the galena surface as hydrophobic lead xanthate salts.The galena-air bubble interactions are repulsive in 1 mM NaCl, with or without xanthate, consistent with the lower galena recovery measured experimentally. An increase to 100 mM NaCl, irrespective of the xanthate addition, resulted in attractive galena-air bubble total interaction energies. The agreement with the experimental results shows the effectiveness of the charge regulated model for estimating the galena and air bubble behaviours during flotation in NaCl solutions.

Comparison of separation of Mn(II), Co(II), and Ni(II) by oxidative precipitation between chloride and sulfate solutions

In hydrometallurgy, precipitation would be easier and simpler than solvent extraction as a separation operation. In this work, the separation performance of Co(II), Mn(II) and Ni(II) by oxidative precipitation was investigated. For this purpose, NaClO was employed as an oxidizing agent and the separation behavior of the three ions was compared between chloride and sulfate solutions by varying some factors such as the dosage of NaClO, solution pH and reaction temperature. By controlling the molar ratio of NaClO to Mn(II), manganese ions(II) were easily separated as MnO2 by oxidative precipitation from both chloride and sulfate solutions. At the same experimental conditions, precipitation percentage of Co(II) from chloride solution was higher than that from sulfate solution, which can be ascribed to the stronger tendency of Co(II) to form complexes with chloride ion than with sulfate ions. Addition of NaCl to sulfate solution and oxidative precipitation at high temperature enhanced the precipitation percentage of Co2O3 and thus separation degree between Co(II) and Ni(II) was improved. Under the optimum conditions, MnO2 and Co2O3 powders with 99.9% purity were completely recovered by oxidative precipitation from chloride solution. By contrast, the purities of the MnO2 and Co2O3 thus recovered from sulfate solution were only 76 and 91%, respectively. Our results indicated that chloride solution would be more effective than sulfate solution in separating Mn(II) and Co(II) by oxidative precipitation with NaClO. Therefore, the use of chloride-based leaching solutions such as HCl and FeCl3 might be better for the leaching medium of spent lithium-ion batteries.

Fabrication and characterization of complex coacervates utilizing gelatin and carboxymethyl starch.

Modified polysaccharides have greatly expanded applications in comparison with native polysaccharides due to their improved compatibility and interactions with proteins and active compounds in food-related areas. Nonetheless, there is a noticeable dearth of research concerning the utilization of carboxymethyl starch (CMS) as a microcapsule wall material in food processing, despite its common use in pharmaceutical delivery. The development of an economical and safe embedding carrier using CMS and gelatin (GE) holds immense importance within the food-processing industry. In this work, the potential of innovative coacervates formed by the combination of GE and CMS as a reliable, stable, and biodegradable embedding carrier is evaluated by turbidity measurements, thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and rheological measurements. The results indicate that GE-CMS coacervates primarily resulted from electrostatic interactions and hydrogen bonding. The optimal coacervation was observed at pH 4.6 and with a GE/CMS blend ratio of 3:1 (w/w). However, the addition of NaCl reduced coacervation and made it less sensitive to temperature changes (35-55 °C). In comparison with individual GE or CMS, the coacervates exhibited higher thermal stability, as shown by TGA. X-ray diffraction analysis shows that the GE-CMS coacervates maintained an amorphous structure. Rheological testing reveals that the GE-CMS coacervates exhibited shear-thinning behavior and gel-like properties. Overall, attaining electroneutrality in the mixture boosts the formation of a denser structure and enhances rheological properties, leading to promising applications in food, biomaterials, cosmetics, and pharmaceutical products. © 2023 Society of Chemical Industry.

Pathway control in metallosupramolecular polymerization of a monoalkynylplatinum(ii) terpyridine complex through competitive complex formation.

Understanding the pathway complexity of supramolecular polymerization in biomimetic systems has been a challenging issue due to its importance in the development of rationally controlled materials and insight into self-assembly in nature. We herein report a kinetic trapping strategy as a new methodology on how to control the pathway of metallosupramolecular polymerization by employing secondary metal ions and/or ligands which form competitive complex species. For this, we proposed monoalkynylplatinum(ii) metalloligand (Pt-L1) derived from a bis(amideterpyridine) receptor with one unoccupied terpyridyl terminal as a coordination site for the secondary metal ion (Ag+ or Fe2+). The inherent pathway complexity intrinsic to the Pt-L1-anchored supramolecular polymerization has been modulated through the incorporation of Ag+ or Fe2+. During the supramolecular polymerization of Pt-L1 in the presence of Ag+ and Fe2+, the added secondary ligand bpy (4,4'-dimethyl-2,2'-bipyridine) or DA18C6 (1,14-diaza-18-crown-6) form complexes as kinetic species, thereby inhibiting spontaneous polymerizations. The supramolecular polymer (SP-I), with a spherical structure composed of Pt-L1 in the absence of metal ions as a kinetic product, did not transform into the thermodynamic product, namely supramolecular polymer (SP-III) with a left-handed fiber structure, due to a high energy barrier. However, the supramolecular polymer (SP-II) with a left-handed fiber structure, which was formed by Pt-L1 in the presence of AgNO3, converted to SP-III upon the addition of NaCl. Additionally, SP-II transformed into supramolecular polymer (SP-IV) upon the addition of Fe(BF4)2, through an on-pathway process. Both the morphological and emissive characteristics of the resulting supramolecular polymers can be fine-tuned via the Pt⋯Pt or Ag⋯Ag interactions as well as through the changes of the coordination geometry depending on the existing Ag+ or Fe2+ ions. The present results have important implications in expanding the scope of pathway complexity to produce a variety of products via kinetically controlled processes involving secondary metal ions and ligands.

Exploration and modulation of the photophysical properties of bromelain in a bioamphiphilic micellar system: comparative studies on the basis of room temperature ionic liquids, anionic surfactants, drugs and salts

A new bioamphiphile sodium-2-decanamyde-2-methyl propanoate (SDMP) was synthesized to study the photophysical properties of bromelain (BM) in its micellar medium, and with the addition of RTILs, SDS, NaCl and NOT using spectroscopic methods.

Accumulation of reactive carbonyl species in roots as the primary cause of salt stress‐induced growth retardation of Arabidopsis thaliana

AbstractSalt stress on plants induces an increase in reactive oxygen species (ROS), which then leads to the formation of reactive carbonyl species (RCS) such as acrolein and 4‐hydroxy‐(E)‐2‐nonenal (HNE), potent cytotoxins generated from lipid peroxides. We recently showed that salt‐stress treatment of Arabidopsis thaliana plants increased RCS levels, and exogenously added RCS‐scavenging chemicals alleviated the stress symptoms, indicating that RCS were responsible for the tissue damage in salt‐stressed plants. To obtain deeper insights into the role of RCS in stressed plants, we here analyzed changes in the levels of various RCS in the roots and shoots of A. thaliana. NaCl (90 mM) addition to the culture medium as a salt‐stress treatment caused growth inhibition and leaf chlorosis. Carbonyl analysis using HPLC revealed that the stress treatment induced a 2‐fold increase in the root levels of RCS, including acrolein, HNE and 4‐hydroxy‐(E)‐2‐hexenal (HHE). In the shoots, basal levels and stress‐induced increases of the RCS were lower than in roots. In the transgenic A. thaliana plants that overexpress the RCS‐scavenging enzyme 2‐alkenal reductase (AER) cDNA under the β‐estradiol (β‐ED)‐responsive promoter, salt stress induced less damage than in the wild‐type under β‐ED supplementation. The AER overexpression suppressed the stress‐induced increases in HNE, acrolein, HHE and (E)‐2‐hexenal in roots and in HNE in leaves, but not the ROS increase. These results suggest that the RCS increase in roots was the primary cause of salt‐induced damages. Enhancing RCS‐scavenging abilities, such as by AER overexpression, could be a new strategy to confer salt‐stress tolerance to plants.

A Study of the Effects of Saltwater on the Formation, Curing and Strength of Concrete

Concrete is extensively used in all construction works such as buildings, bridges, roads and dams worldwide. It is made by simply combining cement, aggregate, sand and water in the appropriate proportion. This paper explores the investigational study on the outcome of using saltwater in coastal regions for blending and curing concrete since palatable water is a deficient asset on the earth. As most of the ions in seawater comprise Na, Mg, Cl- and SO42-, this research aimed to observe how concrete behaves after the addition of NaCl and MgSO4 salt separately for mixing concrete and curing at different concentrations. Concrete cylinders were cured using fresh water as well as saltwater separately. A total specimen of 42 cylinders was cast with 100%, 75% and 50% ion concentrations of NaCl, MgSO4 and freshwater specimens prepared for the reference concrete, which were exhibited for 7 days and 28 days of curing. A comparatively higher compressive strength was found for a 50% salt concentration of MgSO4 and for 75% salt concentration of NaCl. The comparison of compressive strength using NaCl and MgSO4 samples between this research and previous researches was derived for 7 days and 28 days. A correlation between the compressive strength and ion concentrations of NaCl and MgSO4 for 28 days was derived by performing linear regression analysis. The relations obtained by this analysis can be utilized for further prediction of compressive strength at any other ion concentrations of these salts. IUBAT Review, 6(2): 25-40

Preparation of high internal phase pickering emulsions using micron-sized esterified maize starch as the sole effective stabilizer

Preparation of high internal phase Pickering emulsions (HIPPEs) from starch nanocrystals (SNCs) is currently a key area of research. However, the high cost of producing SNCs restricts their usage in the food industry. This study investigated the effectiveness of micron-sized esterified maize starch (M-NMS) as the sole stabilizer for the preparation of HIPPEs. It was found that stable, gel-like HIPPEs with an oil phase volume of 75–90% could be created by using M-NMS granules at a concentration of ≥3.0 wt%. At a pH of 5.0–9.0, the absolute value of zeta potential for all emulsions exceeded 61 mV, indicating high interfacial stability. The addition of NaCl at a concentration of 40–160 mmol/l had no significant effect on the emulsion's viscosity, viscoelasticity, or stability. The gel structure formed by the swollen M-NMS molecular chain predominantly determined the emulsion's performance, as shown by atomic force microscopy.

Effect of Sodium Chloride Concentration on Cooking Time Calculation and Sensory Evaluation of Fish Sausage

This research was conducted to evaluate the effect of the addition of sodium chloride (NaCl) at different concentrations (0–3.0%) on the theoretical and real cooking time and sensory evaluation of the fish sausage. The fish sausage was prepared using 2:1.2:1 minced fish, sago starch, and water with added NaCl at a concentration of 1.5% to the formulation, and the sausage was cooked for 180 seconds (3 min) at 180°C to accomplish both the correct cooking time and sensory evaluation properties. Theoretical and real cooking time methods were calculated using a pre-calibrated thermocouple to reach the target core temperature of 75oC at the centre of the sausage. The optimum NaCl concentration and cooking time were identified from the cooking methods and sensory evaluation. The results revealed that increasing the addition of NaCl to the sausage formulations significantly increased the core temperature of the sausage during cooking. There was a reverse relationship between the added percentage of sodium chloride and the calculated cooking time; as the addition of sodium chloride increased, a shorter cooking time was obtained until we reached the target core temperature of 75oC. The predicted cooking time was 195.171 seconds, and the real cooking time was 180 seconds.

Evaluation of the efficiency of coconut dust extract as a corrosion inhibitor for steel reinforcement in concrete by mass spectrometry

Ethanol extraction was employed to isolate a range of compounds from waste products derived from coconut fiber production (coconut dust) in Ben Tre, Vietnam. Phytochemical screening confirmed the presence of flavonoids, tannins, polyphenols, saponins, alkaloids, flobatannins, and anthraquinones among the extracted substances. FT-IR spectroscopy analysis supported the identification of oxygen and nitrogen atoms within functional groups (e.g., O–H, N–H, C–O) and aromatic rings, characteristic of typical corrosion inhibitors. Mass spectrometry investigations indicated that when St3 steel was exposed to an alkaline solution lacking chlorides, a passive film composed of FeOOH formed on the surface. However, upon the addition of NaCl at a concentration of 1.00 mol/dm3, FeCl, FeCl2Cl–, and FeCl3Cl– compounds were detected across the analyzed surface, while peaks corresponding to FeOO– were absent. Remarkably, areas with the highest concentration of particles corresponded to regions exhibiting visible corrosion damage under magnification. The addition of 2.00 g/dm3 of coconut dust extract to the chloride solution prevents the formation of Fe and Cl compounds on the steel surface. Consequently, only peaks characteristic of FeOO– and organic fragments containing oxygen atoms from the extract were observed. Based on these results, it can be assumed that coconut dust extract has the potential to inhibit local (pitting) corrosion of low-carbon steel (St3) when exposed to aqueous alkaline solutions simulating concrete pore liquid containing chlorides. The addition of 2.00 g/dm3 of the extract has been shown to prevent pitting formation at a chloride concentration of 1.00 mol/dm3. Conversely, in the absence of the extract, visible local corrosion damage was observed upon magnification. These findings provide a basis for further exploration of the protective properties of coconut dust extract as an environment-friendly corrosion inhibitor for mild steel in concrete environments containing chlorides.

Enhancing Resistance to Salinity in Wheat by Using Streptomyces sp. HU2014

Salt stress affects the growth and global production of wheat (Triticum aestivum L.). Plant growth-promoting microbes can enhance plant resistance to abiotic stresses. In this study, we aimed to assess the inoculation of soil with Streptomyces sp. HU2014 to improve wheat tolerance to salt stress from multiple perspectives, including the interaction of the strain, the addition of NaCl, the condition of the wheat, and rhizosphere microbial communities. The results showed that the strain promoted wheat growth under NaCl stress by increasing biomass by 19.8%, total chlorophyll content by 72.1%, proline content by 152.0%, and malondialdehyde content by 106.9%, and by decreasing catalase by 39.0%, peroxidase by 1.4%, and soluble sugar by 61.6% when compared to the control. With HU2014 soil inoculation, total nitrogen, nitrate nitrogen, total phosphorus, and Olsen phosphorus increased, whereas ammonium nitrogen and pH decreased. HU2014 inoculation and/or the addition of NaCl affected the diversity of rhizosphere bacteria, but not fungi. The structure of the microbial community differed after HU2014 inoculation, with Proteobacteria, Acidobacteriota, Bacteroidota, and unclassified fungi being the dominant phyla, and these taxa correlated with the above-mentioned soil parameters. Thus, this study provided a promising way to enhance wheat tolerance to salt stress and improve the agricultural ecological environment by using plant growth-promoting microbes.

The effect of coolant additives on the vapour explosion behaviour in melt droplet impingement experiments

Vapour explosions are a known hazard with potentially devastating consequences in several industries. They might occur when a hot liquid comes into direct contact with a cold and volatile liquid. Eutectic PbS-Cu2S droplet impingement experiments were performed to investigate the effect of the coolant composition on the vapour explosion behaviour. The composition was varied between water with systematic additions of NaCl, MEG, or a combination of both. The experiments were monitored with a hydrophone and a high-speed camera. Also, the resulting debris was sieved for further analysis. The investigation considered the trigger probability and explosion intensity. The latter was quantified via the size of the explosion, the height of the hydrophone signal, and the debris particle size. NaCl additions were found to increase both the trigger probability and the explosion intensity, whereas MEG additions were found to decrease the trigger probability and explosion intensity. However, combined additions of MEG and NaCl resulted in a decreasing trigger probability, while having an unclear effect on the explosion intensity.

Mung Bean Starch and Mung Bean Starch Sheet Jelly: NaCl-Based Characteristics Variation.

Empirical evidence indicates that NaCl can improve the quality of mung bean starch sheet jelly (MBSS) when properly incorporated. In this study, by comparison with a sample without NaCl, the influences of NaCl (1.5-8%, w/w) on the physicochemical and structural properties of mung bean starch (MBS) and the quality of MBSS were investigated. MBS with added NaCl had greater gelatinization temperature and pasting parameters but lower gelatinization enthalpy than native MBS. With the addition of NaCl, the drying rate of MBSS first accelerated and then declined in the oven-drying process. The addition of NaCl improved the cooking properties of MBSS but decreased the hardness of cooked MBSS. Rheological results implied that the linear viscoelastic region of cooked MBSS decreased with the NaCl addition, and the storage modulus and tan δ were more frequency-dependent than the loss modulus of cooked MBSS. The addition of NaCl gradually increased the toughness of dried MBSS and the overall acceptability of cooked MBSS. Furthermore, NaCl decreased the structure order degree of starch in MBSS. Correlation analysis demonstrated that the quality of MBSS had a significant correlation with the molecular and lamellar order of starch. Overall, NaCl could improve the quality of MBSS by regulating the thermal, gelatinizing, and structural properties of MBS.

Synergistic Stabilization of Nanoemulsion Using Nonionic Surfactants and Salt-Sensitive Cellulose Nanocrystals.

Soybean stover is a lignocellulose biomass that is rich in cellulose. In the present study, soybean cellulose nanocrystals (CNCs) were prepared from soybean stover by alkaline treatment, bleaching treatment, acid hydrolysis, dialysis and ultrasonication. The as-prepared soybean CNC was characterized by transmission electron microscopy (TEM), zetasizer and rheometer. The effects of NaCl on the particle size, zeta potential, and viscosity of soybean CNC was studied. Soybean CNC was explored as an emulsion stabilizer for lemongrass-essential-oil-loaded emulsions. Soybean CNCs could stabilize the oil-in-water emulsion against coalescence but not flocculation. The addition of NaCl reduced the creaming index and enhanced the encapsulation efficiency and freeze-thaw stability of the CNC-stabilized emulsion. Salted CNC (i.e., CNC in the presence of NaCl) enhanced the thermodynamic stability (i.e., heating-cooling and freeze-thaw stability) of Tween 80 stabilized emulsion, while unsalted CNC did not. Synergistic effects existed between Tween 80 and salted CNC in stabilizing oil-in-water emulsions. The nanoemulsion stabilized with Tween 80 and salted CNC had a mean particle size of ~70 nm, and it was stable against all thermodynamic stability tests. This is the first study to report the synergistic interaction between salted CNC and small molecular weight surfactants (e.g., Tween 80) to improve the thermodynamic stability of nanoemulsion.

EVALUATION OF METHODS FOR TOTAL RNA EXTRACTION FROM THE ENDOSPERM OF COCOS NUCIFERA VAR. MAKAPUNO IN VIETNAM FOR MOLECULAR ANALYSIS

Sap coconut (Cocos nucifera L. var. makapuno) in Vietnam is a mutant coconut variant; coconut water is in the state of lotus glue, and coconut rice is like cream. For high-quality transcriptome, sequencing, quality, purity and concentration of RNA are the key factors. However, coconut endosperm tissue has higher stiffness and fatness than the leaf tissue, which complicates the extraction process. Moreover, RNA is much more difficult to preserve than DNA. In this study, various RNA extraction methods were examined in Vietnamese waxy coconut endosperm tissue samples. Optimum extraction and preservation of the RNA using the simplest possible chemicals was the objective of this study. The modified CTAB method with LiCl and the TRI reagent method were tested and evaluated. The purity, concentration and quality of RNA after storage were improved. The findings indicated that the TRIsure extraction method with the addition of NaCl and β-mercaptoethanol yielded optimum RNA quality. The RNA concentration was 159 ng/µL, with a purity ratio of 1.94 ± 0.04 for A260/A280 and 1.58 ± 0.02 for A260/230. RNA samples remained stable for up to 3 weeks when stored in absolute ethanol at 8°C–10°C, which significantly reduced their degradation during transportation. This study facilitated the use of simple chemicals for high-quality RNA extraction from coconut endosperm and its preservation for applications in high throughput sequencing.

Effects of NaCl on the Physical Properties of Cornstarch-Methyl Cellulose Blend and on Its Gel Prepared with Rice Flour in a Model System.

This study investigated the impact of NaCl on the physical properties of cornstarch-methyl cellulose (CS-MC) mixtures and their gels prepared with rice flour in a model system. Opposite trends were observed, showing that NaCl led to decreased viscosity of the CS-MC mixtures (liquid-based), whereas a more stable and robust structure was observed for the rice-flour-added gels (solid-based) with the addition of NaCl. The interference of NaCl with the CS-MS blend's ability to form a stable gel network resulted in a thinner consistency, as the molecules of the CS-MS blend may not bind together as effectively. On the contrary, NaCl showed the potential to enhance the protein network within CS-MC gels prepared with rice flour, thereby contributing to an augmentation in the stability or firmness of the cooked gels. Careful utilization of NaCl to optimize the physical properties of the CS-MC blends, as well as the gels based on rice flour, should be performed.

Oxidative behaviour, aggregation and structural properties of silver carp myofibrillar proteins with different molecular states subjected to freeze–thaw process

SummarySilver carp myofibrillar proteins (MP) with different moleculars states were constructed by the addition of NaCl and fracture degree of muscle fibres. Results showed that salt‐dissolved MP (P+) under unfrozen and oxidised state showed higher oxidation degree with higher carbonyl (3.42 nmol mg−1) and dityrosine contents (25.98 a.u.) (P < 0.05) compared with saltless‐polymeric MP (P) and salt‐induced swelling MP (F+) due to addition of salt and broken muscle fibres. After oxidative and freeze–thaw process, P+ group also exhibited more cross‐linking as evidenced by turbidity (0.73), solubility (64.96%) and SDS‐PAGE, but unordered aggregates in P group increased probably due to severe frozen denaturation. Moreover, F+ group of salt‐induced swelling MP from intact muscle fibres suffered less structural damages with higher fluorescence intensity (668.41 a.u.) and higher α‐helix contents (15.56%). Overall, Fish‐ Hua of salt‐dissolved MP had a higher oxidation level and NaCl contributed to improve freeze–thaw stability of MP during freeze–thaw process.

Molecular dynamics study on the effect of inorganic salts on the wettability of surfactants on bituminous coal: Sodium dodecyl sulfate and sodium chloride as representatives

To further enhance the wetting ability of surfactants to coal, the mechanism of improving the wetting performance of SDS to bituminous coal by the addition of inorganic salt NaCl was studied through a combination of molecular dynamics (MD) simulation with experimental measurements. In the experiment part, the surface tensions of the mixed NaCl-SDS solutions and the contact angles on the bituminous coal surface were measured. Furthermore, MD simulations were conducted to investigate the adsorption characteristics and wetting mechanism of a mixed NaCl-SDS solution on the coal surface at the atomic scale. In this process, the static potentials of the H2O molecule, coal molecule and SDS molecule were calculated, and the number of hydrogen bonds (H-bonds) formed throughout the whole simulation process, the average H-bond length, the relative concentration distribution (RCD) curve and the mean square displacement (MSD) curve were obtained. The experimental results showed that the surface tension and contact angle were both decreased by the addition of sodium chloride in mixed solutions. When 0.6 mol/L NaCl was added, the surface tension and contact angle reached the minima of 30.45 mN/m and 13.01°, respectively. The MD simulation results showed that, after the addition of NaCl, diffusion and migration of H2O molecules were limited, the number of H-bonds increases, the average bond length decreased, the sorption between H2O molecules and coal molecules was enhanced, and the hydrophilicity of coal surface was improved, which meant that the wetting ability of SDS solution to bituminous coal was enhanced by adding NaCl. The effect of the added NaCl in improving the wettability of SDS on coal was explored from two perspectives with macroscopic experiments and microcosmic simulations, and the added NaCl improved the effects of dust suppressants, and played a key role in preventing dust hazards in coal mines.

Challenges in surface‐enhanced Raman scattering signal for ethephon detection: Theoretical and experimental approaches

AbstractEthephon, a widely used growth regulator in fruits and vegetables, requires careful monitoring because of its toxicity. However, as far as we know, only two works are found in the literature regarding surface‐enhanced Raman scattering (SERS) ethephon detection. Indeed, obtaining the SERS signal revealed to be challenging. Therefore, we have evaluated the SERS signal of ethephon using theoretical (as density functional theory and charge‐assisted fragment interaction) and experimental approaches, addressing this limited literature knowledge. Theoretical Raman spectra with Ag or Au atoms at reactive sites exhibited enhanced ethephon SERS signal via AgCl bonding, consistent with the experimental data. Multiple experimental procedures were employed to obtain the SERS signal, including pH variations, salt addition, excitation laser lines, time dependency, and different SERS substrates (Ag colloid and Ag island films). Salt addition (NaCl) improved SERS signal, correlating with Ag colloid aggregation. Analysis in Ag colloid showed the pH 7.0 as optimal for ethephon detection, using freshly prepared Ag colloid + ethephon dispersion with ethephon powder being directly dissolved into Ag colloid. Only the AgCl band intensity improved with time. Ag colloid (wet medium — 633 nm laser line) outperformed Ag island films (dry medium — 785 nm laser line).