Concentrations Of Inorganic Salts Research Articles

Efficiently Removing Heavy Metals from High-Salinity Wastewater via Ionic Liquid-Based Aqueous Biphasic Systems.

For the separation of metal ions, ionic liquid-based aqueous biphasic systems (IL-ABSs) offer a promising alternative to solvent extraction. However, the incorporation of an extensive quantity of inorganic salts restricts their practical application. Because heavy metal wastewater often contains high concentrations of inorganic salts, it offers good prospects for the application of IL-ABSs in the separation of heavy metals. In this work, an IL-ABS was formed by tributyltetradecylphosphonium chloride ([P44414]Cl), and simulated high-salinity wastewater (NaCl and Na2SO4 as the main inorganic salts) was used for the separation of heavy metals. The phase diagram results indicated that the formation of a two-phase system required a relatively high salt concentration. The extraction process followed the mechanism of anion exchange; thus, heavy metals such as zinc and cadmium that formed complexes with chloride ions could be effectively extracted (extraction rate >99.5%) with a very fast rate (extraction time <1 min) at a wide pH range (pH = 2-7). After extraction, the metals could be stripped well (stripping rate >99.5%) after contact with the NaOH solution. This research provided a new approach for treating heavy metals in high-salinity effluents, which has the advantages of IL-ABS and avoids the disadvantages of adding large amounts of inorganic salts at the same time.

Experimental study on improving salt resistance of dust suppressing foam with polymers

Mine dust is a prevalent pollutant generated during the mining process, often leading to explosion accidents and causing pneumoconiosis. Foam dust suppression technology has emerged as a promising method for efficient dust control due to its high-efficiency dust collection and ease of use. However, the application of foam in the field has revealed higher concentrations of inorganic salts in the mine dust suppressants, resulting in suboptimal foaming performance. As a result, additional foaming agent and increased concentration are often required to achieve the desired effect, which escalates the cost of mine dust control. To address this issue, this study proposes optimizing the performance of mine dust suppression foam through the incorporation of polymers with excellent salt resistance. In this investigation, foam liquids comprising xanthan gum (XG) and sodium carboxymethyl cellulose (CMC) were tested using FoamScan to evaluate their foaming performance and foam stabilization at various concentrations of inorganic salt. Additionally, the rheological properties of the foam liquids were analyzed by measuring the viscoelastic modulus using an interfacial rheometer. Experimental results demonstrated that the addition of XG and CMC did not compromise the foaming ability of sodium fatty alcohol polyoxyethylene ether sulfate (AES). Moreover, the liquid-carrying capacity of bubbles, in terms of foam stability, was enhanced. Specifically, the foam stabilization remained relatively stable when the XG concentration exceeded 0.5‰, even under different salt concentrations. Interfacial rheological tests revealed that the addition of XG substantially increased the viscoelastic modulus of the foam liquid. Furthermore, the phase angle remained below 45°, indicating the dominant role of the elastic modulus in the foam liquid, resulting in improved bubble resistance to interference and deformation. This experimental study successfully resolved the issue of poor stability in mine dust suppression foam caused by high salt content during the foam preparation process. The findings can significantly contribute to the widespread adoption and application of dust suppression foam technology in mining operations.

The efficient removal of low concentration hexavalent chromium via combining charged microporous membrane and micellar adsorption filtration

Abstract It is challenging to effectively purge wastewater containing heavy metal ions at low concentration. In order to remove trace Cr (VI) from wastewater efficiently, a positively charged microporous membrane was prepared by firstly non-solvent induced phase separation (NIPS) of amphiphilic polymer and secondly surface quaternization modification. The morphologies, surface roughness, surface charge, hydrophilicity, and pore size of membranes were characterized. Based on the dual action of micellar adsorption and charge repulsion, when surfactant is 4 mM and Cr (VI) is 60 ppm, the surface quaternization membrane (Q-MPVD) achieves 99.8 % Cr (VI) rejection simultaneously accompanied by a permeability of 100 LMH/bar. Meanwhile, the effects of STAC concentration, Cr (VI) concentration, pH as well as inorganic salt concentration on the composite micellar size, and Cr (VI) rejection performance were investigated, respectively. Moreover, the Q-MPVD membrane shows an excellent separation stability over a wide pH range, indicating its application perspective in engineering process. In summary, this work provided a positively charged membrane with high-efficiency performance for treating practical trace Cr (VI)-containing industrial wastewater.

Sensing System for Mixed Inorganic Salt Solution Based on Improved Double Label Coupling RFID

As a crucial part in sewage, high-salt wastewater contains abundant corrosive components and heavy metal elements, which makes it difficult for invasive monitoring. Therefore, based on coupling Radio Frequency Identification(RFID) tags, this paper proposes a non-invasive monitoring method for concentration of inorganic salt in sewage. In this method, Cole-Cole model and Slit Cylindrical Capacitance(SCC) model are combined to explore the relationship between capacitance of RFID and concentration of inorganic salt in sewage pipeline. A New Efficient Levenberg-Marquardt(NELM) algorithm is used for regression between relative permittivity and concentration of inorganic salt categorically. Then, measurement data is processed under modified relative permittivity mixing rule of electrolyte and solvent. Finally the concentration of each component in the multi-component inorganic salt wastewater are obtained. Experimental results show that the maximal relative error (MRE) and average relative error(ARE) of single inorganic salt solution are 1.1% and 0.5%, while mixed solution are 2.6% and 1.89%. Such results indicate significant improvement comparing with previous works. Great potential of RFID in working sewage monitoring is sufficiently confirmed.

Influence of Inorganic Salt Additives on the Surface Tension of Sodium Dodecylbenzene Sulfonate Solution

In order to study the effect of inorganic salt additives on the surface tension of a sodium dodecylbenzene sulfonate (SDBS) solution, the surface tension of the mixed system of six common inorganic salt additives, NaCl, CaCl2, AlCl3, Na2SO4, Na2CO3, and NaHCO3, and SDBS was measured, and the effects of the inorganic salt types, surfactant concentrations and inorganic salt concentrations on the surface tension of the SDBS solution were studied. On this basis, three inorganic salts, NaCl, CaCl2 and Na2SO4, were selected, and their effects on the critical micelle concentration (CMC) of the SDBS solution were studied. The experimental results showed that different inorganic salts had different effects on the surface tension of the SDBS solution. The order of effect of the six inorganic salts on the surface tension of the SDBS solution was CaCl2 &gt; NaCl &gt; Na2SO4 &gt; NaHCO3 &gt; Na2CO3 &gt; AlCl3; when the mass fraction of the SDBS solution is high, the influence of the inorganic salts on the surface tension of the SDBS solution is relatively small; with an increase in the concentration of the preferred inorganic salt additives, the surface tension of the SDBS solution decreases first, then tends to be stable, and then increases; a reduction in the critical micelle concentration by the three selected inorganic salt additives shows the trend of 0.7% NaCl &gt; 0.5% CaCl2 &gt; 0.5% Na2SO4.

Surface geochemical anomaly pattern of medium-to-high temperature geothermal systems in South China and its application

The existence of thermal storage will correspondingly increase the temperature of surrounding strata and promote the continuous expansion, volatilization, upward migration, and loss of gas in the strata. As a result, a low-concentration gas field will be formed in the strata above geothermal reservoirs. Geothermal reservoirs could in turn heat formation water and increase the solubility of soluble inorganic salts in the surrounding rocks and the total dissolved solids (TDS) content in the formation water. Since water can strongly wet and permeate strata, the dissolved inorganic salts migrate into upper strata along with water, giving rise to the formation of a high-concentration inorganic salt field in the strata above geothermal reservoirs. A higher geothermal reservoir temperature corresponds to more significant characteristics mentioned above. Therefore, a medium-to-high temperature geothermal system has a surface geochemical anomaly pattern of high inorganic salt concentrations and low gas concentrations (also referred to as the high-salt and low-gas pattern). This pattern is applied to the surface geochemical exploration of the two geothermal fields in Guangdong Province, i.e., the Huangshadong geothermal field in Huizhou City and the Xinzhou geothermal field in Yangjiang City, revealing low-concentration gas fields above both. The application results also show that the exposed thermal spring water in both geological fields has higher concentration of dissolved inorganic salt than the surface water and nearby seawater, forming high-amplitude anomalies on the surface above geothermal reservoirs. These characteristics, as well as the measured temperature at known geothermal wells, verify the validity of the high-salt and low-gas pattern of medium-to-high temperature geothermal systems proposed in this study. Moreover, the high-salt and low-gas pattern proposed predicts three favorable medium-to-high temperature geothermal zones in the surface geochemical exploration of the Shiba Basin near the Huangshadong geothermal field.

Toughening Double Network Hydrogels by Polyelectrolytes.

Hoffmeister effect of inorganic salts has been verified as a promising way to toughen hydrogels, however, the high concentration of inorganic salts may accompany by poor biocompatibility. In this work, for the first time, we find that polyelectrolytes can obviously elevate the mechanical performances of hydrogels through Hoffmeister effect. The introduction of anionic poly(sodium acrylate) (P(iAA)) into poly(vinyl alcohol) (PVA) hydrogel induces the aggregation and crystallization of PVA to boost the mechanical properties of the resulting double network hydrogel: elevation of 73, 64, 28, 135, and 19 times in the tensile strength, compressive strength, Young's modulus, toughness, and fracture energy compared with poly(acrylic acid) (PAA), respectively. It is noteworthy that the mechanical performances of the hydrogels can be flexibly tuned by the variation of polyelectrolyte concentration, ionization degree, relative hydrophobicity of the ionic component and polyelectrolyte type in a wide range. This strategy is verified to work for other Hoffmeister effect-sensitive polymers and polyelectrolytes. Also, the introduction of urea bonds into polyelectrolytes can further improve the mechanical properties and anti-swelling capability of hydrogels. As a biomedical patch, the advanced hydrogel can efficiently inhibit hernia formation and promote the regeneration of soft tissues in abdominal wall defect model. This article is protected by copyright. All rights reserved.

Membrane Filtration Applied to the Purification of Sugarcane Bagasse Mild Alkaline Extracts

Sugarcane bagasse (SCB), a by-product of the sugar industry, is composed mainly of cellulose, hemicelluloses, and lignin, and can be used to replace petrochemical polymers in various applications. In this work, SCB was treated under mild alkaline conditions with 1.5% NaOH (m:v) and a solid:liquid ratio of 1:20 (m:v) at 60 °C, during 6 h. A 10 kDa polysulfone hollow fiber membrane was used for the purification of the extract in different filtration modes, namely concentration and diafiltration, and a combination of both modes. Permeate fluxes and rejection rates were evaluated at different transmembrane pressure (TMP) at the shear rate of 10,187 s–1, at 40 °C. In concentration mode, increasing the volume reduction factor up to 6.1 led to a significant increase in the retention rates of acid-soluble lignin (ASL) and xylan, and a decrease in inorganic salt content in the retentate. In diafiltration mode, after 2.9 diavolumes, the acid-insoluble lignin (AIL) and xylan rejection rates drastically increased, as did the rejection rates of ash.

Facile fabrication of strong and conductive cellulose hydrogels with wide temperature tolerance for flexible sensors

Cellulose-based ionic conductive hydrogels (ICHs) have found extensive applications in flexible electronics and multifunctional sensors. However, simultaneous realization of sufficient conductivity, superior mechanical property and extreme environment tolerance for ICHs remains to be a huge challenge. In this work, a facile one-pot approach was developed to fabricate ICHs by directly dissolving cotton linter cellulose and polyvinyl alcohol (PVA) in a concentrated ZnCl2 solution. By regulating the content of PVA in ICHs, the optimal hydrogel (Gel-5) exhibits a tensile strength of 0.30 MPa, a compressive strength of 2.05 MPa and a conductivity of 8.16 S m−1. Moreover, the resulting dual-network ICHs present high transparency, good thermal reversibility and desirable ionic conductivity. Due to the high concentration of inorganic salts in the porous dual-network structure, the ICH presents good anti-drying and anti-freezing (as low as −90 °C) properties. Such hydrogel can be assembled into multi-functional sensors for human motion and temperature monitoring, and they demonstrate durable sensitivity, cycling stability in a wide operating temperature. This work will shed light on the design of cellulose-based hydrogels with good ionic conductivity and mechanical performance under extreme conditions.

Size Dependence of Liquid–Liquid Phase Separation by in Situ Study of Flowing Submicron Aerosol Particles

Liquid-liquid phase separation (LLPS) of atmospheric particles impacts a range of atmospheric processes. Driven by thermodynamics, LLPS occurs in mixed organic-inorganic particles when high inorganic salt concentrations exclude organic compounds, which develop into a separate phase. The effect of particle size on the thermodynamic and kinetic drivers of LLPS, however, remains incompletely understood. Here, the size dependence was studied for the separation relative humidity (SRH) of LLPS. Submicron organic-inorganic aerosol particles of ammonium sulfate mixed with 1,2,6-hexanetriol and polyethylene glycol (PEG) were studied. In a flow configuration, upstream size selection was coupled to a downstream fluorescence aerosol flow tube (F-AFT) at 293 ± 1 K. For both mixed particle types, the SRH values for submicron particle diameters of 260-410 nm agreed with previous measurements reported in the literature for supermicron particles. For smaller particles, the SRH values decreased by approximately 5% RH for diameters of 130-260 nm for PEG-sulfate particles and of 70-190 nm for hexanetriol-sulfate particles. From these observations, the nucleation rate in the hexanetriol-sulfate system was constrained, implying an activation barrier to nucleation of +1.4 to +2.0 × 10-19 J at 70% RH and 293 K. Quantifying the activation barrier is an approach for predicting size-dependent LLPS in the atmosphere.

Experimental study of the rheology of cellulose nanocrystals-enhanced C22-tailed zwitterionic wormlike micelles

Nano-materials enhanced zwitterionic surfactants fracturing fluids with greatly improved rheological properties are extensively employed in foam fracturing to stimulate unconventional gas/oil reservoirs. In this study, a novel worm-like micelles (WLMs) system composed of erucyl dimethyl amidopropyl betaine (EDAB, C22), alkyl polyglucoside (APG) and cellulose nanocrystals (CNC) is proposed. A series of rheology and dynamic light scattering tests were conducted to determine the optimal concentration, and the influence of various factors, including temperature, pH, and inorganic salts, on the viscoelasticity and structural morphology of WLMs systems were also analyzed. The results show that a 0.3 wt% EDAB/APG/CNC system exhibits optimal viscosity and viscoelastic fluid behavior. The increase of temperature accelerates the breaking rate of WLMs, resulting in a decrease in viscosity, but its shear viscosity can still maintain 87.42 mPa·s at 90 °C and is an order of magnitude greater than that of other systems. The change of pH can disturb the equilibrium state under the electrostatic interaction of EDAB and CNC, and the negative ions in EDAB and CNC molecules are easily protonated in acid medium, resulting in a lower viscosity than alkaline medium and much lower than neutral medium. The viscosity of the EDAB/APG/CNC system increases first and then decreases with the increase of inorganic salt concentration, and reaches a peak at 2.5 wt%. Proppant critical settling velocity tests show that the CNC improves the proppant-carrying capacity of the EDAB/APG/CNC system with favourable critical settling velocity. The CNC enhanced C22-tailed EDAB system provides a basis for optimizing foaming fracturing in unconventional reservoirs.

Lrp as a potential transcriptional regulator involved in stress response in Haloferax mediterranei

The Archaea domain consists of a heterogeneous group of microorganisms with unique physiological properties that occupy a wide variety of niches in nature. Haloferax mediterranei is an extremely halophilic archaeon classified in the Phylum Euryarchaeota, which requires a high concentration of inorganic salts for optimal growth. In haloarchaea, transcription factors play a fundamental role in an adequate adaptation to environmental and nutritional changes, preserving the survival and integrity of the organism. To deepen knowledge of the Lrp/AsnC transcriptional regulator family, a lrp gene (HFX_RS01210) from this family has been studied. Site-directed mutagenesis has allowed us to identify the TATA-box and two potential sites of the transcriptional factor (TF) to its own promoter and autoregulate itself. Several approaches were carried out to elucidate whether this transcriptional regulator is involved in stresses due to heavy metals and limited nitrogen conditions. Characterization of the lrp deletion mutant and the Lrp overexpressed strain, suggests that the level of lrp expression depends on the nitrogen source and the presence of cobalt. The most striking results were obtained in the presence of nitrate as a nitrogen source due to the inability of the deletion mutant to grow. All these results confirm that Lrp is a powerful candidate for a regulatory role in the stress response, particularly under N-limiting conditions and the presence of cobalt.

The effect of inorganic salt on the morphology and nucleation of polyaniline nanofibers synthesized via self-assembly

ABSTRACTPolyaniline (PANI), due to the various and controllable shapes, the environmental stability, the excellent physical and chemical property, has gained significant attention. PANI with abundant morphologies were successfully prepared through adjusting and controlling the state of the initial micelle-like in the micelle-like system composed by aniline and organic acids with relatively weak intermolecular interaction. Although the influence of the inorganic salts on their morphology, including the surface and the diameter, was investigated, the influence of salt on the nucleation of PANI was still unclear. Therefore, PANI nanofibers were fabricated through the addition of inorganic salt such as NaCl, MgSO4 and AlCl3 into the micelle-like composed of aniline and D-camphor-10-sulfonic acid. The influence of types and concentration of inorganic salts, doped acids and temperature on PANI was studied by Transmission Electron Microscope (TEM), UV-vis and Fourier Transform Infrared Spectroscopy (FTIR) spectroscopy. In addition, in situ UV-vis and 1H Nuclear Magnetic Resonance technology (NMR) were applied to observe the process of aniline polymerization, and it was indicated the polymerization rate of aniline changed after the addition of inorganic salt NaCl into the initial solution.

Analysis of aerosol liquid water content and its role in visibility reduction in Delhi

Aerosols undergo significant changes due to water uptake under high RH conditions, leading to changes in physical, optical, and chemical properties. Detailed assessment and investigation are needed to understand better aerosol liquid water content (ALWC) characteristics in highly polluted regions like Delhi. Therefore, in this study, we examined the mass concentration and the factors governing the ALWC associated with PM2.5 in Delhi for two winters (Dec 2019 to Jan 2020 and Dec 2020 to Feb 2021) using the real-time measurements of NR-PM2.5 from Aerodyne aerosol chemical speciation monitor (ACSM) and the application of thermodynamic modeling (ISORROPIA II). The average NR-PM2.5 mass concentration in the 2020–2021 winter was 152 μg/m3, about 50 % higher than the average mass concentration of 102 μg/m3 in 2019–2020. Consequently, the ALWC was also 60 % higher during 2020–2021, with an average mass concentration of 150 μg/m3. ALWC increased exponentially with RH and is significant when RH > 80 %. Further, all the inorganic components of NR-PM2.5 were found to contribute significantly to ALWC uptake; however, the relative contribution varied in different RH conditions. Ammonium sulphate dominated the ALWC uptake among the inorganic components at low RH, but ammonium nitrate was the dominant contributor at high RH. The decreased chloride mass fraction in inorganics in the recent winters reduced its relative contribution to ALWC. High ALWC mass concentration during high PM2.5 and high RH leads to a significant reduction in visibility. We further validated this visibility reduction by estimating the enhanced light scattering coefficient (f(RH)) and found that the hygroscopic growth is responsible for the enhanced visibility reduction during high RH conditions (> 85 %) when light scattering efficiency increased by a factor of >3.5. Sensitivity tests of f(RH) on mass concentration of inorganic salts showed that all the salts contributed almost equally. As revealed in our study, variations in PM2.5 mass concentration and composition despite similar meteorological conditions between different winters indicate changing regional aerosol emissions. Therefore, long-term observations of ALWC and PM2.5 chemical composition are required to arrive at actionable measures and mitigation strategies. Further, the focus should be on reducing the overall inorganic mass concentrations of PM2.5 in general, decreasing the absolute ALWC, and improving visibility.

Ruthenium ion catalytic oxidation depolymerization of lignite under ultra-low dosage of RuCl3 catalyst and separation of the organic products with inorganic salts.

Depolymerization of lignite into valuable chemicals via ruthenium ion catalytic oxidation (RICO) is a potential route for the non-energy utilization of lignite. However, the high cost of the Ru catalyst during depolymerization and the high content of inorganic salts in the product solution limit the development of this route. In this work, RICO depolymerization of lignite was conducted under an ultra-low dosage of RuCl3 catalyst to decrease the usage of the catalyst during the RICO process. Different approaches were attempted to fulfill the separation of benzene polycarboxylic acids (BPCAs) products with the inorganic salts derived from the oxidant NaIO4, including butanone extraction and desalting via crystallization under different temperatures. The results show that lignite can be efficiently depolymerized under the mass ratio of RuCl3/lignite as low as 1/1000 by prolonging the reaction time without decreasing the depolymerization degree and BPCAs yields compared to the commonly used mass ratio of 1/10. Butanone can extract ca. 91% of the total BPCAs in the product solution, and the inorganic salts content (mainly NaIO3) in the extraction solution was as low as 0.19 mg mL-1. A new strategy of first acidification of depolymerization aqueous solution by HCl and then extraction by butanone is proved to be efficient for the separation of BPCAs with inorganic salts. Salting out via crystallization under lower temperature can remove ca. half content of the salts, and the efficiency is inferior to butanone extraction. The low usage of RuCl3 can efficiently decrease the catalyst cost of the RICO process, and butanone extraction can fulfill the enrichment of BPCAs and the separation of BPCAs with inorganic salts. This work is meaningful for the potential application of RCIO depolymerization of lignite for the production of valuable chemicals.

IMPACTOS DA GINÁSTICA AERÓBICA E LIDERANÇA DE TORCIDA EM ESTUDANTES DO ENSINO MÉDIO

ABSTRACT Introduction: Aerobic gymnastics and cheerleading are two sports most high school students are familiar with. Cheerleading is a relatively new sport. Few academic studies are comparing the effects of aerobic training with cheerleading on changes in the fitness of female students in high school. Objective: This paper explores the impacts on fitness by comparing aerobic training and cheerleading in high school girls. Methods: 90 female high school students were selected by random sampling. The three groups of volunteers had their physical fitness measured before and after the test. The research analyzes the obtained data by employing mathematical statistics. Results: The content of protein, muscle, and inorganic salts in the aerobics group and cheerleading group was significantly higher than in the control group, and the obesity rate was significantly lower than the control group in both intervention groups. The percentage of protein, muscle, and lipid in the cheerleading group was the best among the three groups. Conclusion: Both cheerleading and aerobics can improve the physical quality of high school girls. Cheerleading had a good effect on improving physical fitness due to its wide range of movements. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

Bipolar membrane electrodialysis for sustainable utilization of inorganic salts from the reverse osmosis concentration of real landfill leachate

Developing an effective resource utilization method for landfill leachate reverse osmosis concentrate (LLRC) remains a challenge because of the high concentrations of inorganic salts and refractory organic compounds. This study applied a bipolar membrane electrodialysis (BMED) to separate inorganic salts from real LLRC while simultaneously reclaiming inorganic acids and bases. The performance of BMED was affected by operating parameters, such as operating voltage, membrane surface flow velocity, and initial acid-base concentration. With optimized operating parameters, the reclaimed acid-base concentrations, desalination rate, and current efficiency were higher with less energy consumption. Ultimately, 0.41 mol/L acids and 0.40 mol/L bases were reclaimed from LLRC. The reclaimed acids contained 88 wt% HCl and 12 wt% HNO3. The reclaimed bases were 52 wt% NaOH and 45 wt% KOH. Furthermore, the concentrations of arsenic and heavy metals were low enough to safely utilize reclaimed products. The electromigration of organic compounds was controlled by protonation. After excluding the fixed costs, the net profit of 1 m3 LLRC treatment by BMED was $27.630, which showed remarkable economic feasibility. Our research offers a new strategy to realize sustainable utilization of inorganic salts from LLRC.

Experimental Study of the Influence of Inorganic Salts on Foam Stability

The aqueous film-forming foam (AFFF) extinguishing agent is suitable for fighting various hydrocarbon fuel fires due to its dual fire-fighting effect of foam and liquid film. Because the action law and microscopic mechanism of inorganic salts on the stabilization process of surfactant-generated AFFF are not perfect, this paper employs an experimental approach to investigate the effects of inorganic salt types and concentrations on sodium dodecyl sulfate-containing foam systems (SDS). Prior to critical micelle concentration (CMC), increasing inorganic salt concentration decreased solution surface tension, but the opposite was true after CMC. The CMC value of an SDS solution decreases as inorganic salt concentration increases, and the "salting effect" of inorganic salt cations also has an effect on the CMC value. Based on the resistance of the liquid film at the gas-liquid interface affecting gas transport, the foam evolution was divided into three stages: foam generation, liquid drainage, and gas transfer. The effect of inorganic salts on these three stages was studied at the molecular level, and it was discovered that the addition of NH4Cl and MgCl2 could improve the saturation adsorption at the gas-liquid interface, reduce the surface tension of the surfactant solution, and improve foam stability. Meanwhile, inorganic salts can change the force of gas molecules, so the equilibrium force of gas across the liquid membrane increases as inorganic salt concentration increases. Additionally, the addition of inorganic salts raises the diffusive drainage coefficient, but the gravity drainage coefficient still reigns supreme in the predecay period.

Effect of inorganic salt concentration and types on electrophoretic migration of oil droplets in oil-in-water emulsion: A molecular dynamics study

Oil-in-water (O/W) wastewater generally contains inorganic salt ions, which cause energy consumption in the process of electric demulsification. To reveal the influence mechanism of inorganic salt ions on the micro movement of oil droplets in O/W emulsion, the electrophoretic migration of oil droplets with different ion concentration was studied based on molecular dynamics simulation. The results showed that Na+ adsorbed the negative charge on the surface of the oil droplets while Cl- repelled it, leading to a decrease in the electrophoretic mobility and deformation of the oil droplets with the increase of ion concentration. The inhibitory effect of three inorganic salts on oil droplet electrophoretic migration was MgCl2 > CaCl2 > NaCl. The weak interaction between oil, water and ions was mainly van der Waals interaction. When the NaCl concentration was 0.4 mol/L, the oil–water interfacial tension was at its maximum value of 85.14 mN/m. and the deformation degree of oil droplets reached the minimum values of 0.45. The formation of hydrated ions reduces the freedom of water molecules. The above findings uncovered the effect of inorganic salt ions on the electrophoretic migration of oil droplets in O/W emulsions under a DC electric field, which can provide theoretical guidance for the purification of oily wastewater from the molecular level.

Impact of ultrasound and medium condition on production of selenium-enriched yeast

BackgroundUltrasonication was used to stimulate the growth and selenium (Se) biotransformation in Saccharomyces cerevisiae. An optimization study for maximal Se accumulation in S. cerevisiae was conducted using the Plackett–Burman screening method and response surface methodology (RSM) for optimization of conditions. The variables influencing Se biotransformation by yeast, including duration and power of ultrasound, inoculum treatment with ultrasound, duty cycle, growth phase, time, shaking rate, inorganic salt concentration (Se, Zn, Mg, and K), and nitrogen and carbon sources as well as their concentrations were screened using the Plackett–Burman design. ResultsThe main variables were carbon and Se concentration as well as ultrasound power and duty cycle. The lack of fit was insignificant (P > 0.01). The optimum condition for Se accumulation was obtained at Se concentration of 60 µg/ml, carbon source brix of 15, ultrasound of 90 W/L, and duty cycle of 40%. ConclusionsThe results showed that optimization of parameters and application of ultrasonication lead to a successful enhancement (2.78-fold) in the accumulation of selenium by S. cerevisiae. Such enriched yeast can be utilized in bread for increasing consumption of Se in the diet of patients with Se deficiency.How to cite: Alijan S, Hosseini M, Esmaeili S, et al. Impact of ultrasound and medium condition on production of selenium-enriched yeast. Electron J Biotechnol 2022;60. https://doi.org/10.1016/j.ejbt.2022.09.004.