Inorganic Salt Solutions Research Articles

Influence of modification of chemical solution deposition on morphology and conductivity of CaZr0.9Y0.1O3-δ films

Dense uniform films of CaZr0.9Y0.1O3-δ (CZY) electrolyte were grown on porous supporting SrTi0.8Fe0.2O3-δ (STF) electrodes via modified chemical solution deposition technique. Liquid precursor for the film deposition was prepared using a solution of inorganic salts in ethanol and a nanopowder obtained from this solution by drying and precalcining at 550 °C. A complex of techniques including X-Ray Diffraction, Scanning Electron Microscopy and Impedance Spectroscopy were utilized to characterize phase purity, morphological and electrical properties of the deposited films. Distribution of relaxation times was used for separation of the bulk and grain boundary contributions to the total conductivity of the films from the impedance spectra. The suggested modification allows not only reducing the number of liquid precursor deposition steps for fabrication of dense films, but also increasing grain size and conductivity of the films.

Zwitterions as novel phase forming components of aqueous biphasic systems

Abstract A novel class of aqueous biphasic systems (ABS) formed by zwitterions (ZI) has been investigated in the present work. A series of water soluble ZIs have been synthesized using triethylamine, N-Methylimidazole, N-Vinylimidazole, pyridine, N-Methylpyrrolidine, N-Ethylpiperidine and 1,4 butane sultone. The synthesized ZIs were explored for their ability to form biphasic systems in combination with aqueous inorganic salt solutions of K3PO4, K2HPO4 and K2CO3. The phase diagrams for all systems have been constructed through cloud point titration method at 298.15 K and atmospheric pressure. The phase behavior of ZI based ABS have been analyzed to understand the structural effects of ZIs as well as the effect of nature of salt used on the overall phase formation. Further the temperature dependence of the ZI based ABS was also explored by studying the phase behavior at variable temperatures of 298.15, 308.15 and 318.15 K. In order to estimate the applicability of proposed ZI based ABS, extraction experiments have been performed for an alkaloid i.e. caffeine for all synthesized ZIs with K3PO4 and at 298.15 K. ZI based ABS have been found to be capable of single step extraction of caffeine similar to IL based ABS thus providing the possibilities to explore these ZI based ABS as efficient extraction and separation systems.

Flexible and portable graphene on carbon cloth as a power generator for electricity generation

Utilizing flexible and portable device to generate electricity via a natural process has aroused extensive and intensive interest. Herein, a low-cost graphene/carbon cloth (G/CC) is prepared to generate electricity induced by water evaporation that is driven from solar photothermal conversion. The G/CC device can constantly generate electricity approximately up to 0.37 V in 0.5 M NaCl solution through solar-driven water evaporation. High photothermal efficiency up to 83% is achieved when the device is applied to inorganic salt solutions or organic solvents under solar illumination with a power density of 1 kW m−2. This work provides a simple method that can convert the environmental energy into electricity, and develops a new energy harvester as a green power supply system that is feasible in a use of water evaporation, pollutant treatment and medicine disinfection.

Enhanced ability of plasma-activated lactated Ringer's solution to induce A549 cell injury

Non-thermal plasma (NTP) is applicable to living cells and has emerged as a novel technology for cancer therapy. Plasma-activated medium (PAM), which is prepared by the irradiation of culture medium with NTP, induces cell death in cancer cells. However, difficulties are associated with applying PAM to the clinical phase because culture media cannot be used for medical treatments. The objectives of the present study were to demonstrate the inhibitory effects of plasma-activated lactated Ringer's solution (PAL) on the viability of the A549 cancer cell line and elucidate the underlying mechanisms. The anti-tumor activity of PAL was significantly stronger than that of PAM, whereas their concentrations of H2O2 and nitrite were similar. Lactated Ringer's solution (Lac-R) consists of lactate and three types of inorganic salts. The results showing that NTP irradiation of the lactate solution rather than the inorganic salt solution induced the inactivation of catalase were dependent on the presence or absence of nitrite in these solutions. We detected nitrotyrosine in A549 cells treated with PAM or PAL, and the addition of catalase to PAM rather than to PAL reduced its production. The PAL treatment of A549 cells led to mitochondrial dysfunction with the down-regulation of NF-κB-Bcl2 signaling.

Experimental investigation on inorganic salt solution’s undercooling degree under the action of porous media and different concentrations

The undercooling degree of inorganic salt solution has great effect on the characteristic of phase change materials in cooling storage methods. Ammonium chloride solution was chosen as a kind of inorganic salt solution, and the experimental system was built to study the influence on supercooling degree of inorganic salt solution under the effection of concentration and porous media. The heat transfer enhancement method was studied by changing the concentration of inorganic salt solution and the diameter of pellets constituting the porous media. The experimental results show that with the increase in concentration, the value of inorganic salt solution’s supercooling degree and dispersion degree reduced, while the stability increased. The undercooling degree of the 15% ammonium chloride solution decreased by 17.5% compared to the 5% ammonium chloride solution. As the pellet diameter constituting the porous media decreased, the average value of the solution’s undercooling degree and dispersion degree also decreased, while the stability increased. The average value of the solution’s undercooling degree decreased by 21.7% when using 5-mm-diameter pellets compared to the ammonium chloride solution without porous media.

A comparison of I-V characteristics of graphene silicon and graphene-porous silicon hybrid structures

A novel Graphene/Porous Silicon hybrid device is fabricated and its electrical behaviors are studied along with a Graphene/Silicon device. Graphene (G) is prepared by exfoliation of graphite foil in aqueous solution of inorganic salt. Porous Silicon (PS) is fabricated by electrochemical etching of p-type Si. Graphene is deposited on the surface of Si and PS substrates by the Thermal Spray Pyrolysis (TSP) method. The current-voltage relationships of G/Si and G/PS devices are derived and studied under different volumes of graphene. The results reveal that there are important differences in the I–V characteristics of G/Si and G/PS devices in the forward as well as reverse bias. Furthermore, varying the volume of graphene deposition on Si and PS substrates have contrary effects on their I–V characteristics.

Preparation and Characterization of Supercritical CO 2 Nanocellulose Aerogels

This paper uses poplar wood chips as raw materials to prepare nanocellulose (NCC) by sulfuric acid hydrolysis, and then through physical gelling of inorganic salt solution, tert-butyl alcohol (TBA) replacement and supercritical CO2 drying to prepare the nanocellulose aerogels. The characterization analysis and performance test of nanocellulose aerogels were carried out by field emission scanning electron microscope (FESEM), universal mechanical test machine, automatic specific surface area analyzer and thermogravimetric analyzer. The results show that the prepared nanocellulose aerogels are spherical white particles, and the internal structure of the aerogels is a three-dimensional network structure with no collapse, the specific surface area of the aerogels is between 263.5~358.73 cm2/g, and the diameter of the pores mainly distributes between 15~41 nm; as the mass fraction of nanocellulose increases, the compressive strength of the aerogels increases as well and reaches a maximum at 2.39 MPa, the nanocellulose aerogels with a mass fraction of 2.5% have a maximum adsorption capacity of 374 cm3/g.

Thermal carbonization in nanoscale reactors: controlled formation of carbon nanodots inside porous CaCO3 microparticles

Synthesis of carbon nanodots (CNDs) in confined geometry via incorporation of dextran sulphate into pores of CaCO3 microparticles is demonstrated. The preparation process included three steps: co-precipitation of solutions of inorganic salts and carbon source, thermal treatment and CaCO3 matrix removal. We show that geometric constraints can be used to precisely control the amount of source material and to avoid formation of large carbon particles. Analysis of TEM data shows particle size of ~3.7 nm with narrow size distribution. Furthermore, we found that variation in pore morphology has a clear effect on CNDs structure and optical properties. CNDs with graphene oxide like structure were obtained in the nanoporous outer shell layer of CaCO3 microparticles, while less ordered CNDs with the evidence of complex disordered carbons were extracted from the inner microcavity. These results suggest that confined volume synthesis route in CaCO3 nanopores can be used to precisely control the structure and optical properties of CNDs.

Plasma Polishing of Stainless Steels – The Electrolyte Concentration Vs. Gloss Level

Abstract The technology of plasma polishing in electrolyte is considered as environmental friendly alternative to the common electrochemical polishing process. The solutions of the electrolyte use no acids or toxicants, but the environmental safe, low concentrated aqueous solutions of various inorganic salts are used instead. The dependence of the gloss level of the treated surface upon the electrolyte concentration as well as upon the voltage is examined in this paper. The specimens of stainless steel were used for plasma polishing in ammonium sulphate based electrolyte. The influence of the voltage on the overall properties of the process is discussed, as well.

Aqueous salt solution liquid membranes, supported by nanoparticles, for water extraction from the atmosphere via air dehumidification

AbstractBACKGROUNDMembrane technology is a promising solution for the development of a sustainable air dehumidifier because it is, in general, considered a cost‐effective technology and, moreover, water recovered from the air via membrane‐based dehumidification process can be recycled.RESULTSThe efficiency of aqueous salt solution liquid membranes that were prepared by a nano‐sized additive supporting method and applied for the dehumidification of air, was evaluated in terms of the water permeability and condensed water recovery rate. It was found that not only the nature of the selective membrane material but also the type of membrane supporting material has an impact on the overall liquid membrane performance. Membranes supported by surface treated carbon black nanoparticles showed a water recovery rate of 12 g h−1 at 75–80%RH and average water permeability of 9 × 10−12 kmol m/(m2 s kPa). The most selective liquid membranes were LiBr and CaCl2, supported by surface treated carbon black, with water vapor/air separation factor of 34 300 and 21 700, respectively.CONCLUSIONSThis work for the first time demonstrates the applicability of aqueous inorganic salt solutions in liquid membranes for dehumidification applications. Prepared liquid membranes showed moderate condensed water recovery rates and membrane stability over 1 month. © 2018 Society of Chemical Industry

Effects of solvents and solutes on glass-transition thermodynamics and kinetic fragility for amine and alcohol solutions of inorganic salts

We have used differential scanning calorimetry (DSC) to investigate the thermodynamic and kinetic properties of the glass transition of simple amine and alcohol solutions of inorganic salts. Although the glass-transition temperature (Tg) increases with the addition of salts, in common with other solutions, the concentration dependence of the heat-capacity change (∆Cp) at Tg and the kinetic fragility index (m) are quite different for the amine and alcohol solutions. The thermodynamic and kinetic properties depend more strongly on the solvents than on the solutes. By comparing the DSC data with Raman results, we suggest that the glass-transition thermodynamics and kinetics are controlled mainly by the strength or stability of hydrogen-bond structures and the properties of dominant intermolecular interactions in the solutions.

Kaolinitin kıvam limitleri üzerine inorganik tuz çözeltilerinin etkileri

This study presents the effect of different inorganic salt solutions
 (KCl, BaCl2, MgCl2, KNO3, Na2SO4
 and MgSO4) at different concentrations on geotechnical properties
 (Atterberg Limits) of kaolinite material which can be used as impermeable
 bottom liner in barrier systems. Since the use of distilled water or tap water
 is far from being representative of the in-situ conditions in landfills, salt
 solutions were used to investigate the leachate effect on liner materials.
 Additionally, the mineralogical characterization of kaolinite was studied.  Atterberg limits, specifically the liquid
 limit (LL) and plastic limit (PL) that were used for classifying the clayey
 soil samples according to the Unified Soil Classification System were
 determined whereas mineralogical studies performed included XRD, BET and FT-IR
 analyses. Results indicated that all salt solutions have a considerable effect
 on the consistency limits of kaolinite. The liquid limit values of kaolinite
 decreased with increasing chemical concentration whereas plastic limit values
 increased. It is observed that the effects of the divalent and trivalent
 cations on kaolinite were more apparent than those of monovalent cations. As a
 result chemical solutions decrease liquid limit values of high plasticity
 kaolinite materials,  tend to reduce the
 thickness of the DDL and flocculate the kaolinite particles, resulting in
 reduction of swelling and increasing of hydraulic conductivity.

Use of Adaptive Methods to Solve the Inverse Problem of Determination of Composition of Multi-Component Solutions

This study considers solving the inverse problem of determination of salt or ionic composition of multi-component solutions of inorganic salts by their Raman spectra using artificial neural networks. From the point of view of data analysis, one of the key problems here is high input dimensionality of the data, as the spectrum is usually recorded in 1–2 thousand channels. The two main approaches used for dimensionality reduction are feature selection and feature extraction. In this paper, three feature extraction methods are compared: channel aggregation, principal component analysis, and discrete wavelet transformation. It is demonstrated that for neural network solution of the inverse problem of determination of salt composition, the best results are provided by channel aggregation.

Optical Property Measurements and Single Particle Analysis of Secondary Organic Aerosol Produced from the Aqueous-Phase Reaction of Ammonium Sulfate with Methylglyoxal

Reactions involving the dicarbonyl species methylglyoxal (MG) have been suggested as an important pathway for the production of secondary organic aerosol (SOA) in the atmosphere. Reaction in an aqueous inorganic salt solution, such as ammonium sulfate (AS), leads to the formation of light-absorbing brown carbon (BrC) product. We report on an investigation of the optical properties of BrC aerosol generated from the aqueous-phase reaction between MG and AS as a function of aging time using calibrated cavity ring-down spectroscopy (CRDS) at a wavelength of 403 nm. The retrieved real index of refraction at 403 nm is n = 1.558 ± 0.021, with an imaginary index value of k = 0.002 ± 0.004; these values do not appear to change significantly with aging time over the course of 22 days and are similar to the AS aerosol values. The small complex index suggests that BrC aerosol formed from this pathway may not significantly impact radiative forcing. Measurements of the aerosol optical properties show significant deviat...

Hydrothermal assisted decoration of NiS2 and CoS nanoparticles on the reduced graphene oxide nanosheets for sunlight driven photocatalytic degradation of azo dye: Effect of background electrolyte and surface charge

The semiconductor NiS2 nanoparticles with an average size of 10 ± 0.317 nm were successfully deposited on the reduced graphene oxide (rGO) sheets by simple hydrothermal method. The synthesized nanocomposite was characterized by various instrumental techniques like XRD, FTIR, FESEM, EDX, HRTEM, fluorescence spectrophotometer analysis. In this study we mainly focus on the determination of the surface potential values of NiS2-rGO and CoS-rGO nanocomposite under different experimental conditions and evaluated the photodegradation efficiency towards azo dye Congo Red (CR) molecule under natural sunlight irradiation. We found that the surface charge (zeta potential) of the both nanocomposite materials in presence of different inorganic ions salt solutions like NaCl, NaNO3, Na2SO4, MgCl2, CaCl2 etc. is varied based on the polarizability of the ions as well as pH of the suspension. Different inorganic ions present in the catalyst suspension can alter the surface charge of the catalyst by forming a double layer around the molecule and thus change the electrostatic interaction between the dye molecule and the catalyst surface which change the degradation efficiency of the photocatalyst towards CR molecule. The photocatalytic efficiency of NiS2-rGO and CoS-rGO nanocomposite towards CR degradation was found to be 97.03% and 88.03% in 40 min, respectively under same experimental condition whereas NiS2 and CoS nanoparticles without support exhibited photodegradation efficiency 57.89% and 50.52%, respectively. The observed improved photocatalytic activity of the metal sulfide-rGO nanocomposite results the presence of synergistic effect between the metal sulfide nanoparticles and the rGO sheets of the photocatalysts which inhibits the recombination rate of photogenerated electrons and holes. The mechanism of the degradation process was investigated by photoluminescence study in presence of terephthalic acid and also quenching experiment in presence of isopropanol and benzoquinone. The photocatalyst was characterized after degradation process and found that the crystallinity and the morphology of the nanocomposite remained unchanged. The ion-chromatography experiment confirms the formation of non-toxic products after degradation. The present study focuses on the importance of the use of metal sulphide-rGO nanocomposite towards environment remediation process and study of the influence of inorganic salts on the surface charge of the photocatalyst as well as on the degradation process.

Neural Network Solution of an Inverse Problem in Raman Spectroscopy of Multi-Component Solutions of Inorganic Salts: Group Determination as a Method to Increase Noise Resilience of the Solution

Many inverse problems are incorrect or ill-conditioned. This makes them very sensitive to noise in the input data. In the previous studies of the authors, it was shown that under certain conditions simultaneous determination of several parameters allows increasing the resilience of the neural network solution to noise in the input data. In the present study, applicability of this approach to the inverse problem of spectroscopy, which consists of determining the concentrations of 10 ions in a multi-component solution of inorganic salts by Raman spectra, is demonstrated.

Study of Efficiency of Dividing the Problem Space as a Means to Improve Solution of Multi-parameter Inverse Problem by Adaptive Methods

The considered multi-parameter inverse problem is determination of concentrations of salts or ions in multi-component water solutions of inorganic salts by Raman spectroscopy with subsequent spectra analysis by a non-linear adaptive method (multilayer perceptron type artificial neural networks (ANN) and by a linear adaptive method (partial least squares (PLS) method based on principal component analysis). Dividing the problem space into parts by data clustering simplifies the problem within each cluster but reduces the number of samples. This study compares efficiency of application of this approach for problems with different complexity (determination of concentrations of five salts, or ten salts, or ten ions) and with various distributions of samples over concentration range of the components. Based on experimental results, limitations and areas of application of the approach are discussed.

Effect of oil type on stability of high internal phase water-in-oil emulsions with super-cooled internal phase

ABSTRACTThis study considered the stability and rheology of a type of high internal phase water-in-oil emulsions (W/O) emulsion. The aqueous phase of the emulsions is a super-cooled inorganic salt solution. The oil phase is a mixture of industrial grade oils and stabilizer. Instability of these systems manifests as crystallization of the metastable dispersed droplets with time. This work focused on the effects of oil polarity and oil viscosity on the stability of these emulsions. Ten types of industrial oils, covering the viscosity range 1.4–53.2 cP, and with varying polarity, were used in combination with polymeric poly(isobutylene) succinic anhydride (PIBSA) and sorbitan monooleate (SMO)-based surfactants. The effect of oil relative polarity on rheological parameters of the emulsion was evident mainly in the emulsions stabilized using polymeric surfactant, whereas the oil viscosity did not show any significant effect. The optimum stability of the emulsions stabilized with SMO was achieved using high polar oils with a viscosity of 3 ± 0.5 cP. However, when using the PIBSA surfactant, the best emulsion stability was achieved with low polar, high viscosity oils.

Determination of common ginsenosides in Kang'ai injection by aqueous two-phase extraction with deep eutectic solvents and HPLC-UV/DAD

In this work, four kinds of deep eutectic solvents (DESs), composed of choline chloride (ChCl) and several alcohols, were synthesized and characterized by 1H NMR and FT-IR spectra. Based on DES (ChCl and 1,4-butanediol) and inorganic salt solution (dipotassium phosphate, K2HPO4), aqueous two-phase system (ATPS) coupled with high-performance liquid chromatography has been developed and applied. This method was used for the efficient extraction and determination of eight common ginsenosides (including ginsenoside Rg1, Re, Rf, Rg2, Rb1, Rc, Rb2 and Rd) in the traditional Chinese medicine injection named Kang'ai injection. To achieve optimum extraction performance, the experimental conditions were optimized, including type and amount of DES and salt, ultrasound time, temperature and pH value. In the dynamic linearity range, experimental results showed satisfactory recoveries of analytes ranging from 92.7–110.8% with the relative standard deviations (RSDs) ranging from 1.2–3.9%. It has been proved that DES-ATPS has great potential for determination of active ingredients in traditional Chinese medicine injection as well as samples in other analytical science field.

Influence of sealing post-treatments on the corrosion resistance of PEO coated AZ91 magnesium alloy

Abstract The effect of three different post-treatments carried out on Plasma Electrolytic Oxidation (PEO) coated magnesium alloys are evaluated in terms of characterisation and corrosion resistance. Special interest is given to the role of a common additive (NaF) to the coating properties. The post–treatments are based on immersion sealing processes in aqueous solutions of inorganic salts (cerium and stannate based salts) and alcoholic solution of an organic acid (octodecylphosphate acid, ODP). Sealing mechanisms for each post-treatment are proposed. Cerium and stannate sealings are based on filling of the pores with the products of dissolution/precipitation reactions, while the ODP acid sealing is based on the formation of a thin layer of ODP over the coating through specific interactions between the polar part of the organic acid and the coating surface. All coatings are evaluated by salt fog test and analysed by electrochemical impedance spectroscopy. All sealings show a slight increase in the corrosion resistance of the coatings formed in the NaF-free electrolyte, but their positive influence is boosted in case of the coatings obtained in the NaF-containing electrolyte. This is related to the chemical and morphological changes at the coating surface induced by the presence of NaF in the electrolyte.