Calcium Chloride Aqueous Solution Research Articles

Best operating conditions to produce hydroxyapatite nanoparticles by means of a spinning disc reactor

In this work, Mg2+ doped hydroxyapatite (Mg-HAP) nanoparticles were produced by a reactionprecipitation process by using a spinning disc reactor (SDR) at high rotational speed. The production process of these nanoparticles consisted of the neutralization reaction between two aqueous solutions of calcium chloride and ammonia orthophosphate at room temperature. By operating at pH = 10, a high purity Mg-HAP nanoparticles were obtained. In particular, they were 51 nm in average size when the two reagents were fed over the disc symmetrically at 3 cm from the disc center and a rotational speed of the disc reactor equal to 1400 r/min was adopted.

Accurate description of calcium solvation in concentrated aqueous solutions.

Calcium is one of the biologically most important ions; however, its accurate description by classical molecular dynamics simulations is complicated by strong electrostatic and polarization interactions with surroundings due to its divalent nature. Here, we explore the recently suggested approach for effectively accounting for polarization effects via ionic charge rescaling and develop a new and accurate parametrization of the calcium dication. Comparison to neutron scattering and viscosity measurements demonstrates that our model allows for an accurate description of concentrated aqueous calcium chloride solutions. The present model should find broad use in efficient and accurate modeling of calcium in aqueous environments, such as those encountered in biological and technological applications.

Isobaric heat capacity of potential liquid desiccant solutions containing calcium chloride and its mixtures

Desiccant cooling and drying systems have attracted considerable attention in recent years because they can enhance the quality of dried products and reduce the use of conventional source of energy. Calcium chloride (CaCl2) aqueous solution is the cheapest and most readily available liquid desiccant that could be used in desiccant cooling and drying systems, but it has the disadvantage of being instable depending on the inlet air conditions and the concentration of the desiccant in the solution. CaCl2 + LiCl (1:1 mass) and CaCl2 + Ca(NO3)2 (5:2 mass) mixtures are thought to be the two most potential liquid desiccants with their relatively high performance and high economic efficiency. The main purpose of this research is to obtain the basic thermodynamic properties (isobaric heat capacities) of the aqueous solutions of CaCl2 and its two specially composed mixtures. The measurements were carried out at temperatures range from 308 to 348 K and different concentrations determined under consideration of the working conditions of the liquids in systems. Scanning calorimetry was applied and a specialized experimental unit for heat capacity measurements of liquids was used in this research. Based on the results, semiempirical equations as functions of temperature and solute concentration were obtained. The deviation between the equations and experiment values showed good agreements, which confirmed the capability of these equations to be used in engineering applications.

Antioxidant activity of fucose-containing sulfated polysaccharides obtained from Fucus evanescens by different extraction methods

The fucose-containing sulfated polysaccharides (FCSPs) from Fucus evanescens were obtained via different procedures: by hot acidic extraction and with aqueous calcium chloride solution, followed by separation FCSPs using anion-exchanging chromatography. Chemical characteristics of these polysaccharide fractions were determined. It was shown that extraction with aqueous calcium chloride solution provides a purified preparation of the FCSPs. The crude polysaccharide and its chromatography purified fractions obtained by this method have significantly lower contents of laminaran, uronic acids, and polyphenols in comparison with FCSPs obtained by hot acid extraction. All polysaccharides exhibited total antioxidant capacity and 1,1-diphenyl-2-pycrilhydrazyl (DPPH) radical-scavenging activity and low 2,2′-azino-bis 3-ethyl benzothiazoline-6-sulfuric acid (ABTS) radical-scavenging activity. A strong positive correlation between polyphenol content in FCSPs and their antioxidant activity was found. This fact may indicate that phenols play a key role in the previously described antioxidant capacity of FCSPs.

CO<sub>2</sub> Fixation Using MEA and CaCl<sub>2</sub> Aqueous Solutions

The saturated CO2 loadings in monoethanolamine (MEA) aqueous solutions at normal temperature and pressure were measured. The calcium chloride (CaCl2) aqueous solution was added into the CO2 loaded MEA aqueous solution to converse the ionic form of CO2 (CO32-) to CaCO3 precipitation. The influence of the addition of CaCl2 on the CO2 fixation was illustrated.

Dissolution of hornet silk in aqueous solution of calcium chloride

Dissolution of hornet silk in aqueous solution of calcium chloride

Dissolution Properties of Silk Cocoon Shells and Degummed Fibers from African Wild Silkmoths

Silk cocoon shells and degummed fibers from four African wild silkmoth species were studied and compared with the industrial standard, Bombyx mori, for their dissolution properties. Nine M aqueous Lithium bromide, Calcium chloride and Sodium thiocyanate solution systems were used. Efficiency of the solvent systems was determined by the percentage of dissolved silk cocoon shells and degummed fibers after three hours of treatment. Degummed fibers were more readily soluble than the cocoon shells. B. mori cocoon shells (51.5%) and fibers (59.3%) had higher solubility than their wild counterparts. Among the wild species, Gonometa postica cocoon shells and degummed fibers had the highest solubility (37.3 and 51.7%, respectively). Lithium bromide was the most effective dissolving agent for both the cocoon shells and fibers (41.2 and 84.5%, respectively). Argema mimosae, Anaphe panda and Epiphora bauhiniae showed lower solubility across the solution systems used. The Scanning Electron micrographs showed A. panda fibers exhibited gelling property after dissolution while E. bauhiniae and A. mimosae had cracked and broken fibers exposing the fibriliar structures. The difference in the chemical orientation and composition of the fibers might have contributed to the variability in the dissolution behaviour.

Extraction and Characterization of Silk Fibroin from Waste Silk

Waste silk fibers were dissolved in calcium chloride aqueous solution. Effect of calcium chloride concentration on silk solubility was studied. Dialysis method was used to purify the dissolved silk fibroin. The purified silk fibroin was characterized by FTIR and thermoanalysis technique. Results showed that the purified silk fibroin mainly had irregular curly conformation. The glass transition temperature of the regenerated silk fibroin reached 90.6°C-135°C, higher than 78.9°C-135°C before purification. Thermal weight loss temperature by 50% was 490.3°C differing from 429.7°C before purification.

Role of calcium carbonate morphology on thermal and mechanical properties of HDPE

Calcium carbonate (CaCO3) microparticles with four different morphologies, which are cubic, acicular, spindle and sphere-like, were prepared using calcium chloride (CaCl2) and sodium carbonate (Na2CO3) aqueous solutions containing various additives. High density polyethylene (HDPE)/CaCO3 composites were prepared using a HAAKE Rotational Rheometer. The thermal behaviour, mechanical properties and the rheology property were investigated and characterised by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), capillary rheometry and universal testing machine. The result shows the addition of CaCO3 to HDPE can increase the decomposition temperature and decrease the melting temperature and crystallization temperature. Sphere-like CaCO3 is the best form in improving the thermal stability and toughness of the composites; while the cubic CaCO3 can cause negative effect to the toughness.

Microwave assisted synthesis of bacterial cellulose-calcium carbonate composites

The effect of microwave irradiation on the calcium carbonate (CaCO3) deposition on bacterial cellulose (BC) membranes was investigated. The experiments were conducted at atmospheric pressure using calcium chloride and sodium carbonate aqueous solutions as starting reactants. The following parameters varied: the exposure time at microwave irradiation and the concentrations of calcium chloride starting solutions. The BC-CaCO3 composites were characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). From the known polymorph of calcium carbonate, calcite and vaterite were deposed on bacterial cellulose membranes in the presence of microwave irradiation doses which were used in this work. Water vapor permeability and pencil scratch hardness were investigated for BC-CaCO3 composites and compared with control samples obtained without microwave irradiation. Significant differences between morphology and even polymorphism of the calcium carbonate crystals were observed for the irradiated samples in comparison with those obtained in the absence of microwave irradiation.

Chemical activation of clay in cement mortar, using calcium chloride

Clay exhibits pozzolanic activity, if it is used in high-strength Portland cement. The pozzolonic reactivity of the clay can be enhanced by various methods. In this work the effect of clay on the strength of cement has been investigated in the presence and absence of CaCl2.2H2O as a chemical activator. It was found that the strength of cement mortar has been significantly increased by using an aqueous solution of calcium chloride instead of water. The addition of CaCl2.2H2O decreased the evaporable moisture and pH of the extract as compared to the hardened cement paste, which shows enhanced pozzolanic reactions between lime and clay. The optimum clay replacement level was found to be 10% without activator and 20% in the presence of 4% CaCl2.2H2O. The parameters such as the strength development and water extraction showed that CaCl2.2H2O was a good chemical activator for a clay-cementitious system.

Highly scalable nanoparticle–polymer composite fiber via wet spinning

ABSTRACTMagnetic nanoparticles have continued to gather the interest of researchers due to the unique physical properties of materials found at this size scale. Herein, the production of composite magnetic fibers composed of iron oxide nanoparticles suspended in alginate is described. These materials were produced via wet spinning of a sodium alginate solution into a bath of an aqueous solution of calcium chloride. The magnetic fibers were found to have similar mechanical properties to normal alginate fibers, and exhibited superparamagnetic behavior when subjected to an external DC magnetic field. In addition, the particle loaded fibers demonstrated the potential to produce significant amounts of heat when exposed to an AC magnetic field, suggesting these new materials could be applicable to a variety of applications including magnetic hyperthermia. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1975–1980, 2013

Fundamental Characteristics of Bioprint on Calcium Alginate Gel

The goal of this study is to fabricate precision three-dimensional (3D) biodevices those are micro fluidics and artificial organs utilizing digital fabrication. Digital fabrication is fabrication method utilizing inkjet technologies. Electrostatic inkjet is one of the inkjet technologies. The electrostatic inkjet method has following two merits; those are high resolution to print and ability to eject highly viscous liquid. These characteristics are suitable to print biomaterials precisely. We are now applying for bioprint. In this paper, the electrostatic inkjet method is applied for fabrication of 3D biodevices that has cave like blood vessel. When aqueous solution of sodium alginate is printed to aqueous solution of calcium chloride, calcium alginate is produced. 3D biodevices are fabricated in case that calcium alginate is piled.

Effect of pore size on the performance of composite adsorbent

Three kinds of commercial silica gels with pore size of 2-3, 4-7 and 8-10 nm respectively are used for preparing composite adsorbents by soaking them into the aqueous solution of calcium chloride. The test result indicates that both the water uptake and adsorption rate of composite adsorbents prepared from 4-7 and 8-10 nm silica gels improve greatly compared to pure silica gels, but they do not for 2-3 nm silica gels. The silica gel with pore size of 2-3 nm is not suitable for preparing the composite adsorbent by impregnation method due to the pore blockage because of the small pore size. The SCP and COP of the adsorption chiller with sample SA50 are 128.3 Wkg(-1) and 0.27 respectively at the hot source temperature of 90 A degrees C, which are largely superior to that of SA0. Hence using the composite adsorbent instead of the pure silica gel can reduce the size of the adsorption chiller.

Chemical modulation of crystalline state of calcium oxalate with nickel ions

BackgroundWe explored that the presence of nickel ions in the precipitation medium affected size, shape and crystalline phase of the precipitated particles of calcium oxalate, whereas the applied synthesis conditions strongly influenced their uniformity. MethodsAqueous solutions of oxalic acid and calcium chloride, containing varying amounts of nickel sulfate, were mixed at room temperature and allowed to sonicate for various periods of time. The obtained particles were characterized by SEM, XRD, TG/DTA, and FTIR. ResultsResults revealed that particle morphology of calcium oxalate and their hydration states were dependent upon the chemical composition of the reactant solutions. For instance, the particles precipitated out in the form of dihydrate and having prismatic, and discs shaped particle morphology, when nickel ions were introduced in the starting reactant solution in different amounts. In contrast, the calcium oxalate particles precipitated under identical conditions in the absence of nickel ions were in the form of flakes with corrugated edges. Obvious variations were also found in the XRD patterns and crystallite size of these three solids. Heat treatment produced changes in the surface morphology of these particles due to loss of material and converted them calcium oxide. ConclusionsGentle mixing of aqueous solutions of calcium chloride and oxalic acid in the absence and presence of nickel ions produced precipitated particles of calcium oxalate. Chemical composition of the reactant solutions and their order of mixing were found to be the key parameters in controlling the particle morphology and their hydration/crystalline state. Heat treatment at the elevated temperature transformed the as-prepared calcium oxalate to calcium oxide with visible changes in surface features of the particles.

Bioactive dentin replacement

Replacement of dentin with a material popularly marketed as Biodentine (Septodont, Saint Maur des Fausses, France), a new tricalcium silicate-based cement, has recently been commercialized and advertised as a bioactive material. Its clinical application and physical properties have been widely described. Biodentine, a new biologically active cement which has dentin-like mechanical properties and can be used as a dentin replacement in the tooth crown and root region. The cement consists mainly of a tri- and dicalcium silicate powder, which is mixed with an aqueous calcium chloride solution. As regards biocompatibility, long- term impermeability, antibacterial properties, induction of hard tissue regeneration, stability, low solubility, non-absorbability and ease of handling, Biodentine fulfils the requirements found in the literature for a material suitable for these purposes. On the basis of the good material properties of Biodentine, this cement is an interesting alternative to the conventional materials which were hitherto recommended. Biodentine can therefore confer advantages in day-to-day practice and with correct diagnosis contribute to the long-term maintenance of the vitality of the dental pulp and to the retention of teeth. However, little scientific data is available at present.

Mathematical modelling and experimental investigation of the hybrid desiccant cooling system

In this paper, an experimental study has been conducted on the hybrid desiccant cooling system by removing the latent heat and sensible heat of air separately by mixing it with the desiccant solution in a counter flow manner. This makes air totally dry and thus saves the energy to cool the air in the refrigeration system. The desiccant chosen here is the aqueous solution of calcium chloride. The packed bed inside the absorber as well as the regenerator consists of a polypropylene cascade ring for the efficient mixing of air and desiccant solution. The effects of various parameters such as desiccant inlet temperature, air inlet temperature, mass flow rate of air and desiccant solution have been studied to investigate the performance of the system. Comparing the results with previous studies, a fair agreement has been reported.

Study on poly(D,L‐lactic) microspheres embedded in calcium alginate hydrogel beads as dual drug delivery systems

AbstractThis work is to develop a novel dual drug delivery system that can simultaneously load and release 18β‐glycyrrhetinic acid (GA, a hydrophobic drug) and bovine serum albumin (BSA, hydrophilic model drug) in a single formulation. The system consists of poly(D,L‐lactic) (PDLLA) microspheres embedded in calcium alginate hydrogel beads. The GA‐loaded microspheres were first prepared and then dispersed in the aqueous solution of sodium alginate and BSA. The resulting suspension was dropped into aqueous calcium chloride solution to obtain the dual drug delivery system. The morphology of the microspheres and beads, the drug content and loading efficiency, the interaction between GA and PDLLA, and the drug release behaviors were studied. Scanning electron microscope (SEM) revealed that the PDLLA microspheres were homogeneously distributed in the beads. Differential scanning calorimetry (DSC) measurement suggested certain interaction between GA and PDLLA, and the crystal structure of GA was influenced by the polymer. The dual release in vitro showed a rapid BSA release but a sustained GA release in all the systems. Furthermore, the release rate of BSA was accelerated by increasing PDLLA/alginate ratio, while the release rate of GA was decreased, and the release of both hydrophobic and hydrophilic drugs could be adjusted by changing the ratio of PDLLA/alginate. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 20122

A Pitzer-based characterization of aqueous magnesium chloride, calcium chloride and potassium iodide solution densities to high temperature and pressure

A comprehensive characterization of densities/apparent molar volumes for the aqueous solutions of magnesium chloride, calcium chloride and potassium iodide to high temperatures and pressures has been performed based on the Pitzer equations. The unusual availability of overlapping high quality independent sets of experimentally measured data for these systems allows the relevant thermodynamic quantities to be calculated with a high degree of confidence over wide ranges of conditions (< 8molkg−1; 273–573K; 0.1–100MPa). A realistic assessment of experimental uncertainty indicates that an adequate description of volumetric behaviour is achieved by the standard Pitzer model without extensions. The experimental accuracy implied by differences between independent observers, however, is more than one order of magnitude worse than typically claimed estimates of experimental precision.

Toward quantifying the composition of soft tissues by spectral CT with Medipix3

To determine the potential of spectral computed tomography (CT) with Medipix3 for quantifying fat, calcium, and iron in soft tissues within small animal models and surgical specimens of diseases such as fatty liver (metabolic syndrome) and unstable atherosclerosis. The spectroscopic method was applied to tomographic data acquired using a micro-CT system incorporating a Medipix3 detector array with silicon sensor layer and microfocus x-ray tube operating at 50 kVp. A 10 mm diameter perspex phantom containing a fat surrogate (sunflower oil) and aqueous solutions of ferric nitrate, calcium chloride, and iodine was imaged with multiple energy bins. The authors used the spectroscopic characteristics of the CT number to establish a basis for the decomposition of soft tissue components. The potential of the method of constrained least squares for quantifying different sets of materials was evaluated in terms of information entropy and degrees of freedom, with and without the use of a volume conservation constraint. The measurement performance was evaluated quantitatively using atheroma and mouse equivalent phantoms. Finally the decomposition method was assessed qualitatively using a euthanized mouse and an excised human atherosclerotic plaque. Spectral CT measurements of a phantom containing tissue surrogates confirmed the ability to distinguish these materials by the spectroscopic characteristics of their CT number. The assessment of performance potential in terms of information entropy and degrees of freedom indicated that certain sets of up to three materials could be decomposed by the method of constrained least squares. However, there was insufficient information within the data set to distinguish calcium from iron within soft tissues. The quantification of calcium concentration and fat mass fraction within atheroma and mouse equivalent phantoms by spectral CT correlated well with the nominal values (R(2) = 0.990 and R(2) = 0.985, respectively). In the euthanized mouse and excised human atherosclerotic plaque, regions of calcium and fat were appropriately decomposed according to their spectroscopic characteristics. Spectral CT, using the Medipix3 detector and silicon sensor layer, can quantify certain sets of up to three materials using the proposed method of constrained least squares. The system has some ability to independently distinguish calcium, fat, and water, and these have been quantified within phantom equivalents of fatty liver and atheroma. In this configuration, spectral CT cannot distinguish iron from calcium within soft tissues.