Aqueous Solutions Of CaCl2 Research Articles

Sonoluminescence of Aqueous Solutions of CaCl2 and NaCl: The Effect of Concentration

Sonoluminescence of Aqueous Solutions of CaCl2 and NaCl: The Effect of Concentration

Highly increased hydrovoltaic power generation via surfactant optimization of carbon black solution for cellulose microfiber cylindrical generator

Recently, abnormal climates caused by environmental pollution have adversely affected the world, and demand for future renewable energy is increasing rapidly. Electronic generators, which allow current to flow through the interaction between conductive particles and water, are gaining significant attention. We have fabricated hydrovoltaic power generators with materials that can maximize the electrokinetic effects by simple dip-coating process. We prepare carbon black solutions and then coat this solution onto the cellulose acetate microfiber cylinder (CMC) for the electrode. In addition, optimization of the carbon black solutions is conducted by measuring and analyzing their surface properties to obtain stable electrical energy. Various carbon black solutions are prepared using cationic surfactants, anionic surfactants, and a nonionic surfactant. Each solution is then dip-coated onto cellulose nanofibers and dried to form a cellulose acetate microfiber cylindrical generator (CMCG). Both sides of CMCG are connected to an electrometer for electricity generation measurement, and a drop of 0.1 ml CaCl2 aqueous solution is dropped onto one side of CMCG. Finally, we can successfully fabricate a hydrovoltaic power generator with a large power output relative to its volume. A small CMCG of 2.5 cm had a current of 100 µA and a voltage of 0.3 V.

Powders Synthesized from Solutions of Calcium Chloride, Sodium Hydrogen Phosphate, and Sodium Sulfate for Bioceramics Production

Fine powders of brushite CaHPO4·2H2O, ardealite Ca(HPO4)x(SO4)1−x·2H2O (Ca(HPO4)0.5(SO4)0.5·2H2O), and calcium sulfate dihydrate CaSO4·2H2O—all containing sodium chloride NaCl as a reaction by-product—were synthesized from 0.5 M aqueous solution of calcium chloride CaCl2, sodium hydrophosphate Na2HPO4 and/or sodium sulfate Na2SO4. Powder of ardealite Ca(HPO4)x(SO4)1−x·2H2O (Ca(HPO4)0.5(SO4)0.5·2H2O) was synthesized by precipitation from aqueous solution of calcium chloride CaCl2 and mixed-anionic solution simultaneously containing the hydrogen phosphate anion HPO42− (Na2HPO4) and sulfate anion SO42− (Na2SO4). Sodium chloride NaCl, presenting in compacts based on synthesized powders of brushite CaHPO4·2H2O, ardealite Ca(HPO4)x(SO4)1−x·2H2O (Ca(HPO4)0.5(SO4)0.5·2H2O) and calcium sulfate dihydrate CaSO4·2H2O, was responsible for both low-temperature melt formation and the creation of phase composition of ceramics. Heterophase interaction of components led to the resulting phase composition of the ceramic samples during heating, including the formation of chlorapatite Ca5(PO4)3Cl in powders of brushite and ardealite. The phase composition of the ceramics based on the powder of brushite CaHPO4·2H2O containing NaCl as a by-product after firing at 800–1000 °C included β-Ca2P2O7, and Ca5(PO4)3Cl. The phase composition of ceramics based on the powder of ardealite Ca(HPO4)x(SO4)1−x·2H2O (Ca(HPO4)0.5(SO4)0.5·2H2O) containing NaCl as a by-product after firing at 800 and 900 °C included β-Ca2P2O7, CaSO4, and Ca5(PO4)3Cl; after firing at 1000 °C, it includedCaSO4, Ca5(PO4)3Cl and Ca3(PO4)2/Ca10Na(PO4)7, and after firing at 1100 °C, it included CaSO4 and Ca5(PO4)3Cl. The phase composition of ceramics based on powder of calcium sulfate dihydrate CaSO4·2H2O containing NaCl as a by-product after firing at 800–1100 °C included CaSO4 as the predominant phase. The phase composition of all ceramic samples under investigation consisted of biocompatible crystalline phases with different abilities to biodegrade. For this reason, the created ceramics can be recommended for testing as materials for treatment of bone defects using regenerative medicine methods.

Влияние сшивающих агентов на матриксные свойства гидрогелевых структур на основе альгината натрия

A comparative study of gelation processes in aqueous solutions of sodium alginate initiated by their chemical crosslinking with divalent ions Ca2+ or Ba2+ was carried out. 3D cryoprinted hydrogel scaffolds of certain architectonics were formed from the studied compositions containing various concentrations of crosslinking agents. It is shown that the increase in the crosslinking agent concentration from 2 to 10 wt. % leads to the improvement in the strength characteristics of alginate structures. At the same time, scaffolds crosslinked with 10 % aqueous solutions of both CaCl2 and BaCl2 retain their structural stability during 21 days of incubation in a culture medium at a temperature of 37 °C. During in vitro experiments on cultures of mesenchymal stem cells derived from rat adipose tissue, samples crosslinked with Ba2+ ions were found to demonstrate a moderate cytotoxic effect and showed their inability to maintain cell adhesion, unlike non-toxic scaffolds crosslinked in CaCl2 aqueous solutions. In vivo analysis of experimental samples on an intramuscular implantation model for male Wistar rats also confirmed moderate cytotoxicity of alginate scaffolds formed using Ba2+ ions as crosslinking agents. The results obtained allow us to assert that of all the studied by us materials, sodium alginate crosslinked with a 10% CaCl2 aqueous solution can be considered the most promising for various biomedical applications.

Microfluidic dual picoinjection based encapsulation of hemoglobin in alginate microcapsules reinforced by a poly(L-lysine)-g-poly(ethylene glycol).

Hemoglobin (Hb) encapsulation inside polysaccharide hydrogels has been considered a possible red blood cell (RBC) surrogate in transfusiology. Here we report on the microfluidic dual picoinjection assisted synthesis of Hb encapsulated alginate-poly(L-lysine)-g-poly(ethylene glycol) beads. This process is realized by the on-chip injections of blended Hb alginate solutions in emulsified aqueous calcium chloride (CaCl2) droplets followed by a subsequent injection of an aqueous PLL-g-PEG into each emulsified aqueous droplet. The proposed fabrication approach was realized using a flow-focusing and two picoinjection sites in a single PDMS device. Aqueous CaCl2 solution was emulsified and infused with Hb-alginate solution as the squeezed droplet passed through the first picoinjection site. The injection of PLL-g-PEG to reinforce the microgel and minimize the protein leaching was realized in the second picoinjection site located downstream from the first in the same microfluidic channel. In this process, monodisperse Hb-alginate-PLL-g-PEG particles with a diameter around the size of RBCs (9 μm) were obtained with around 80% of the 7.5 mg ml-1 Hb included in the injected aqueous alginate retaining in the obtained microparticles. Microparticles with Hb loading (32.8 pg per bead) and retention (28.8 pg per bead) over a week of storage at 4 °C are in accordance with the average amount of Hb per RBC. The Hb-alginate-PLL-g-PEG microbeads fabricated in the size range of RBCs are significant for further exploration.

Synthesis and characterization of superabsorbent hydrogels based on carboxymethyl cellulose and agar: Agar for smart swelling and controllable delivery

The current study described a thorough analysis of the adsorption characteristics of a hydrogel that was chemically connected and built on agar and carboxymethyl cellulose (CMC). With regard to swelling %, the Agar-Agar/ECH/CMC hydrogel was created under ideal conditions. In order to achieve the highest percentage of swelling, different response parameters were changed. The structure and morphology of the hydrogels were characterized by FT-IR spectroscope, thermogravimetric analysis and scanning electron microscope. The results revealed that the CMC contributed to the enhanced size of pore, whereas Agar-Agar as a strong backbone in the hydrogel to support it for keeping its appearance. Their equilibrium swelling ratio in distilled water and different physiological fluids were evaluated, indicating the maximum swelling ratio in water reached an exciting level of 1000 as the hydrogels still keeping a steady appearance. Moreover, the hydrogels exhibited smart swelling and shrinking in NaCl or CaCl2 aqueous solution, as well as the release behavior of bovine serum albumin (BSA) that could be controlled by changing CMC content. The Agar-Agar -based hydrogels are promising for the applications in the biomaterials area.

Transcriptomics-based Analysis of the Response of Sugar Content in Litchi Pulp to Foliar Calcium Fertilizer Treatment

Ten 16-year-old trees were used as test materials to investigate the effect of foliar calcium fertilizer on the sugar content of ‘Feizixiao’ litchi (Litchi chinensis Sonn.) pulp. The experiment began 35 days after anthesis (DAA) in 2020 and 2021, and the treatment was a foliar spray application of 0.3% CaCl2 aqueous solution, whereas the control was a foliar spray application of water. The sugar content, sucrose-metabolizing enzymes, and ATP-dependent phosphofructokinase (PFK) activities in pulp were measured in 2020 and 2021. Transcriptome sequencing (RNA-seq) was performed on RNA samples from treatment and control fruit pulps at 35, 63, and 69 DAA (full mature stage) in 2020, and 10 genes were chosen for confirmation by real-time polymerase chain reaction (PCR) in 2020 and 2021. At full maturity, the soluble sugar content in the calcium-treated group was extremely significantly or significantly higher than that in the control group. After 63 DAA, the net sucrose-metabolizing enzyme activity in the calcium-treated group was significantly higher than that in the control group. Furthermore, at full maturity, the calcium-treated group had significantly higher sucrose synthase cleavage activity and significantly lower PFK activity than the control group. Fifty-four highly expressed genes in the glycolytic pathway (EMP) were screened from transcriptome data, including hexokinase, PFK, and pyruvate kinase genes; 87% of these genes were downregulated in the treatment group compared with the control group at 69 DAA in 2020. The linear regression between RNA-seq and real-time PCR results was significant in 2020 (r = 0.9292) and 2021 (r = 0.8889). When the fruit is fully ripe, calcium treatment increases net sucrose-metabolizing enzyme activity by increasing sucrose synthase cleavage activity, promoting the accumulation of reducing sugars, and it downregulates phosphofructokinase gene expression in EMP, promoting sugar accumulation.

Adsorption and Lubrication of Glutamic Acid-Based Surfactant with Calcium Ions.

The adsorption and lubrication of an amino acid-based surfactant at the solid/liquid interface were studied in the presence of calcium ions. The surfactant used here was disodium N-dodecanoylglutamate (C12Glu-2Na). The solid surface used in this study was hydrophobically modified to mimic the hydrophobicity of the skin surface. Quartz crystal microbalance with dissipation monitoring (QCM-D) measurements revealed that the anionic surfactant was adsorbed on the hydrophobically modified solid surface. The replacement of the surfactant solution with CaCl2 aqueous solution resulted in the desorption of the surfactant to some extent; however, a rigid and elastic adsorption film interacting with calcium ions remained on the solid surface. The adsorption film containing calcium ions lowered the kinetic friction coefficient in aqueous media. The insoluble calcium salt of the surfactant, dispersed in the solution phase, also contributed to lubrication. We expect that the usability of personal care products formulated using amino acid-based surfactants is relevant to such adsorption and lubrication properties.

Effect of calcium chloride solution on the spontaneous combustion of coal using Olpiński method

The article concerns the effect of the additive on the inhibition of the coal spontaneous combustion process (CSC) by the Olpiński method. The influence of inhibitors on CSC in this method has not been studied so far. Coal samples used in the experiment were taken from Polish coal mines, from which four samples with the symbols S1, S2, S3, and S4 were created, respectively. For each coal sample, a spontaneous combustion index was tested following the Olpiński's method. In addition, analogous tests were performed for coal samples treated with an aqueous CaCl2 solution. A 20% CaCl2 solution has proved to be the most advantageous. Based on the Olpiński method, a fire incubation period is determined in natural conditions on a mine site. Based on the results of CaCl2 inhibition, the extension of that period for examined coals was determined. The results obtained can provide valuable references for developing technology in CaCl2 usage to prevent spontaneous fires in coal mines.

Gelation-based feed-stock technologies for HVOF thermal spray development: Micro-composite powder preparation and HVOF coating microstructure

The current study proposes use of the polysaccharide, sodium alginate, as a gelation aid to ‘solidify’ aqueous suspensions, comprised of micron-sized ceramic-metal particles, into spherical, micro-composite ‘cermet’ feedstock powders. These feedstock powders, with finely divided ceramic and metallic components, can then be used for the preparation of high velocity oxygen fuel coatings and/or laser deposition cladding. Sodium alginate gelation is typically based on ion exchange, and a variety of gelation agents have been examined in the present work. It is shown that aqueous solutions of CaCl2, Ca-acetate, Al-nitrate, methanol, acetic acid, and 5 % HCl acid are all capable of gelling alginate droplets through a simple cross-linking mechanism. Consequently, spraying a sodium alginate containing ceramic-metal particle suspension, with a suitable air atomising nozzle, into an aqueous bath of one of the outlined solutions allows the production of nominally spherical ‘cermet’ feedstock particles. In the present work, TiC-Ni3Al micro-composite cermet particles have been successfully produced, and then analysed both before and after a sintering heat-treatment. Furthermore, rheological assessment of the colloidal suspensions both prior to and during the gelling stage are also described. As a preliminary ‘proof-of-principle’, an initial set of HVOF coatings has also been prepared using the gelled feedstock material, and initial characterisation of these coatings is presented.

Regeneration of As(V) loaded granular activated carbon through desorption in FeCl3, CaCl2 and MgCl2 aqueous solutions

As(V) adsorption on granular activated carbon (GAC) and subsequent desorption in dH2O was modeled using the pseudo-first and pseudo-second order kinetic models. Regeneration was achieved by immersing loaded GAC in NaCl, FeCl3, CaCl2 and MgCl2 aqueous solutions. As(V) detection after desorption was highest for NaCl but subsequent adsorption was lowest. Regeneration was highest in FeCl3 solution of pH 2 followed closely by pH 3, but As(V) precipitation appeared superior at pH 3. Molar ratios of Fe, Ca and Mg to As were tested in the range of 0.75:1 to 12:1 where a logarithmic relation was found between the molar ratio and As(V) desorption as diluted in HNO3 and H2O and subsequent adsorption. Precipitation was nearly complete in FeCl3, limited in MgCl2 at a ratio of 12:1 and not observed in CaCl2. While kinetic values were lower than in previous tests, the pseudo-first and pseudo-second order models could accurately describe desorption in CaCl2 and MgCl2 but not in FeCl3 due to precipitation. Desorption in FeCl3 was most effective in precipitating As(V), being highest at a molar ratio of 6:1, but regeneration was slightly higher at a molar ratio of 12:1.

Anomalous ion hydration and association in confined aqueous CaCl2 solution

On the contrary, in the bulk electrolyte, an abnormal ion association between Ca 2+ and Cl - in the CNTs with diameters from 1.085 nm to 1.220 nm is observed, where Ca 2+ and Cl - mainly exist in the form of contact ion pair (CIP) • An abnormal ion association between Ca 2+ and Cl - in 1.085 nm to 1.220 nm CNT. • Confinement enhances the hydration capacity of Ca 2+ in sub-nanoscale CNTs (d < 1.085 nm), while that of Cl - is greatly reduced. • The weakening of hydration capacity by confinement is the internal driving force for the ion association. Confined aqueous CaCl 2 solution plays an important role in biochemistry, geochemistry, electrochemistry, etc . In the present work, molecular dynamics simulation is employed to investigate the structures of aqueous CaCl 2 solution in carbon nanotubes (CNTs) with different diameters. An abnormal ion association between Ca 2+ and Cl - in the CNT with a diameter from 1.085 nm to 1.220 nm is observed, being completely different from the bulk electrolyte solution, where Ca 2+ and Cl - exist mainly in the form of contact ion pair. Confinement enhances the hydration capacity of Ca 2+ in subnanoscale CNTs (d < 1.085 nm), whereas the hydration capacity of Cl - is greatly reduced, although both Ca 2+ and Cl - have different degrees of dehydration. The hydration capacity of Cl - and Ca 2+ is the weakest in 1.085 nm and 1.220 nm CNTs, respectively, and the weakening of hydration capacity by confinement is the internal driving force for the ion association.

Broccoli microgreens treated with CaCl2 solution absorb calcium atoms and accumulate them as Ca(II) hydrated ions

Broccoli microgreens treated with 10 mM CaCl2 aqueous solution were investigated to clarify whether they absorb calcium (Ca) atoms and what chemical states absorbed Ca species take. X-ray fluorescence (XRF) measurements using synchrotron radiation were performed to map Ca concentrations in cotyledon (seed leaf) of broccoli microgreens. The mapping pixel size was 20 μm × 20 μm. The broccoli microgreens treated with 10 mM CaCl2 aqueous solution show Ca concentrated areas in the cotyledon. On the other hand, no Ca concentrated areas were observed for the cotyledon of the other broccoli microgreens that were treated with purified water. The Ca chemical state of the Ca concentrated areas was studied by x-ray absorption near edge structure (XANES) spectra. The obtained XANES spectrum of the Ca concentrated area shows the characteristic features of CaCl2 aqueous solution, and it does not correspond to the XANES spectrum of CaCl2 powders.

Super-strong and anti-tearing poly(vinyl alcohol)/graphene oxide nano-composite hydrogels fabricated by formation of multiple crosslinking bonding network structure

As load-bearing material in biomedical-applications as cartilage replacement, artificial meniscus and tendons, etc., poly(vinyl alcohol) (PVA)/graphene oxide (GO)-tannic acid (TA) nano-composite hydrogels with multiple-crosslinking network were fabricated by establishing freezing/thawing-annealing-swelling method. By TA anchoring, PVA molecules were grafted onto GO surface efficiently, and strong interfacial interaction led to exfoliation and uniform distribution of GO in matrix. By introducing annealing process, the crystallinity and crystallite size of PVA increased and introducing GO-TA led to more perfect and denser crystalline structure, while physical crosslinking network centered on GO-TA and hydrogen bond-abundant crystalline phase formed, resulting in increasing crosslinking density of hydrogel. By further swelling in CaCl2 aqueous solution, hydroxyl-Ca2+ coordination formed, and multiple-crosslinking network was constructed with high crosslinking density. The tensile strength and fracture toughness of composite hydrogel were remarkably improved, reaching 14.38 MPa/27.93 MJ/m3, approximately 11-/26-fold higher than those of neat PVA hydrogel, while tearing strength was significantly enhanced, attributed to high energy dissipation through unzipping multiple interactions.

Solubilities of Amino Acids in Aqueous Solutions of Chloride or Nitrate Salts of Divalent (Mg2+ or Ca2+) Cations.

The solubilities of glycine, l-leucine, l-phenylalanine, and l-aspartic acid were measured in aqueous MgCl2, Mg(NO3)2, CaCl2,, and Ca(NO3)2 solutions with concentrations ranging from 0 to 2 mol/kg at 298.2 K. The isothermal analytical method was used combined with the refractive index measurements for composition analysis guaranteeing good accuracy. All salts induced a salting-in effect with a higher magnitude for those containing the Ca2+ cation. The nitrate anions also showed stronger binding with the amino acids, thus increasing their relative solubility more than the chloride anions. In particular, calcium nitrate induces an increase in the amino acid solubility from 2.4 (glycine) to 4.6 fold (l-aspartic acid) compared to the corresponding value in water. Amino acid solubility data in aqueous MgCl2 and CaCl2 solutions collected from the open literature were combined with that from this work, allowing us to analyze the relations between the amino acid structure and the salting-in magnitude.

Structure of Aqueous CaCl2 Solutions by X-ray Scattering and Density Functional Theory

Structure of Aqueous CaCl2 Solutions by X-ray Scattering and Density Functional Theory

Calcium Carbonate@silica Composite with Superhydrophobic Properties.

In this paper, spherical calcium carbonate particles were prepared by using CaCl2 aqueous solution + NH3·H2O + polyoxyethylene octyl phenol ether-10 (OP-10) + n-butyl alcohol + cyclohexane inverse micro emulsion system. Then, nanoscale spherical silica was deposited on the surface of micron calcium carbonate by Stöber method to form the composite material. Scanning electron microscope (SEM), X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) were used to characterize the morphology and structure of the composite material. It is found that the surface of the composite material has a micro-nano complex structure similar to the surface of a “lotus leaf”, making the composite material show hydrophobicity. The contact angle of the cubic calcium carbonate, spherical calcium carbonate and CaCO3@SiO2 composite material were measured. They were 51.6°, 73.5°, and 76.8°, respectively. After modification with stearic acid, the contact angle of cubic and spherical CaCO3 were 127.1° and 136.1°, respectively, while the contact angle of CaCO3@SiO2 composite was 151.3°. These results showed that CaCO3@SiO2 composite had good superhydrophobicity, and the influence of material roughness on its hydrophobicity was investigated using the Cassie model theory.

Measurement of Solubility of CO2 in NaCl, CaCl2, MgCl2 and MgCl2 + CaCl2 Brines at Temperatures from 298 to 373 K and Pressures up to 20 MPa Using the Potentiometric Titration Method

Understanding the carbon dioxide (CO2) solubility in formation brines is of great importance to several industrial applications, including CO2 sequestration and some CO2 capture technologies, as well as CO2-based enhanced hydrocarbon recovery methods. Despite years of study, there are few literature data on CO2 solubility for the low salinity range. Thus, in this study, the solubility of CO2 in distilled water and aqueous ionic solutions of NaCl, MgCl2, CaCl2 and MgCl2 + CaCl2 were obtained in a low salinity range (0–15,000 ppm) at temperatures from 298–373 K and pressures up to 20 MPa using an accurate and unconventional method called potentiometric titration. An experimental data set of 553 data points was collected using this method. The results of the experiments demonstrate that increasing pressure increases the solubility of CO2 in various brines, whereas increasing temperature and salinity reduces the solubility. The role of different ions in changing the solubility is elaborated through a detailed discussion on the salting-out effect of different ionic solutions. To verify the experimental results of this research, the solubility points obtained by the potentiometric titration method were compared to some of the well-established experimental and analytical data from the literature and a very good agreement with those was obtained.

Transparent conductive films based on Ag nanowires and alginate hydrogel

In this study, we report that the high-performance transparent conductive films based on silver nanowires (AgNWs) can be fabricated in a single-step spin-coating process by simply introducing a biocompatible polymer (alginate, Alg) into an aqueous suspension of AgNWs. The presence of Alg in the aqueous suspension enables AgNWs to be deposited on the substrate at a higher density, and AgNWs are uniformly distributed on the substrate without aggregation. In addition, through the treatment process using CaCl2 aqueous solution, the conductivity of the AgNWs films can be further improved and their adhesion to the substrate is also enhanced.

Effect of calcium chloride on the self-ignition behaviours of coal using hot-plate test

The effect of calcium chloride (CaCl2) on the self-ignition behaviours of coal was studied under air atmosphere in this paper. Aqueous CaCl2 solutions (50, 100, 200, and 300 g/L) was used to treat a non-caking coal sample with high self-ignition potential, and the minimum auto-ignition temperature (MAIT) of the coal dust layer was determined using hot plate test to affirm thermal runaway. Both thermogravimetric analyzer and differential scanning calorimetry (TGA-DSC) were applied to investigate the decomposition of the samples. Results showed that CaCl2 generated a coating film with dense slurry-like envelope on the particle surface, which took an inhibition effect at low thermal conditions (before crossing point) because of heat absorption of moisture evaporation and oxygen diffusion resistance of pore structure blockage. The MAIT of the CaCl2-treated coal sample was increased from 210 to 240 °C, with a max elevation of 30 °C in comparison to H2O-Coal sample. However, opposite effect was also found at higher temperatures (after the crossing point). For 50 g/L CaCl2-Coal sample on hot surface of 240 °C, the calculated inhibiting rate at 10 and 50 min was 54.8% and −115.6%, respectively, suggesting that the catalysis effect at the later stage after ignition was over two times than the inhibiting effect at the initial self-ignition process. The Ca2+ in the form of its oxides (CaO and CaO2) at higher thermal conditions promoted the diffusion of oxygen to the coal surface and expanded the main combustion zone, suggesting a catalytic role in the coal combustion.