Aqueous Inorganic Solutions Research Articles

A proposed method of bubble absorption-based deep dehumidification using the ionic liquid for low-humidity industrial environments with experimental performance

Liquid desiccant deep dehumidification (LDDD) is an excellent way to achieve low-carbon transformation of low-humidity industrial buildings. Currently, it is essential to improve its ability to produce lower humidity air (i.e., with a dew point below −10 °C). Functional ionic liquids (ILs) with extremely low vapor pressure, non-crystallization, and non-corrosion are ideal substitutes for high mass fraction aqueous inorganic solutions (e.g., LiCl, LiBr) in traditional liquid desiccant deep dehumidification. Meanwhile, the bubble absorption mode allows water vapor to condense on the huge contact surface between the bubbles and desiccant. Accordingly, it is expected to solve the low wettability and transfer unit number (NTUm) in falling-film absorption mode caused by the high viscosity of ILs. Thus, a new method of bubble absorption-based deep dehumidification using the IL is proposed. To validate it, the bubble absorption-based deep dehumidifier using a novel ionic liquid (BADD-IL) is developed and tested under different operating conditions. Besides, its moisture effectiveness is compared with those of falling film absorption-based dehumidifiers. The results show that increasing the liquid height, superficial velocity, as well as lowering the solution temperature, can strengthen the deep dehumidification performance, effectiveness and cooling ability to varying degrees. The increase of liquid height and superficial velocity promotes the gas-liquid interfacial area from different aspects, thus enhancing the transfer efficiency. Notably, the insufficient interfacial areas caused by low solution temperature cannot prevent better transfer efficiency dominated by high potential difference. Moreover, the NTUm of BADD-IL has a wide adjustment range (0.1–1.7), and the minimum supply air humidity ratio and maximum moisture effectiveness can reach 1.1 g/kgda and 81%, respectively. In overall, this study aims to further explore the deep dehumidification potential of ILs, and inform ideas for the LDDD development.

Mg-alloys in water – hydrophilic ionic liquid mixtures: Is there a negative difference effect?

Commercial purity Mg and Mg-alloy AZ61 were exposed at open circuit potential and under anodic polarization in two ionic liquids containing 10 wt% of water, formed by acetate anion and methylpyrrolidinium cation, substituted with either aliphatic (ILA) or etheric (ILE) chain. Hydrogen evolution strongly increased under anodic polarization (negative difference effect, NDE) in ILA, but not ILE. In both electrolytes Mg(OH)2-film formed on Mg but not on AZ61. The NDE suppression did not correlate neither with the presence of carboxylate, nor with the absence of Mg(OH)2, indicating strong differences between magnesium-water interactions in IL-water mixtures and in inorganic aqueous solutions.

Molecular Simulations of Feldspar Surfaces Interacting with Aqueous Inorganic Solutions: Interfacial Water/Ion Structure and Implications for Ice Nucleation

Molecular Simulations of Feldspar Surfaces Interacting with Aqueous Inorganic Solutions: Interfacial Water/Ion Structure and Implications for Ice Nucleation

Regulating the Fluorescence Emission of CdSe Quantum Dots Based on the Surface Ligand Exchange with MAA

Cadmium selenide (CdSe) quantum dots (QDs) is a promising semiconductor and fluorescence nanocrystal with quantum size effect. To address the problem of fluorescence emission during the process of the ligand transformation of colloidal cluster CdSe QDs from nonpolar organic solvents to polar inorganic aqueous solutions, the surface ligand exchange with mercapto acetic acid (MAA) was proposed. It was attributed to the Cd‐O bond breaking and the Cd‐S bond formation. The intensity and wavelength of fluorescence emission spectra could be adjusted by controlling the concentration of MAA. The photoluminescence (PL) spectra and UV‐Vis absorption spectra of colloidal cluster CdSe QDs indicated that the electronic properties of the interface varied with the exchange of the surface ligands. Moreover, the band‐edge emission quenching occurred and the maximum redshift of the PL spectrum could reach 28 nm. The enhancement of the deep trap emission peaks of CdSe QDs appeared in 600‐900 nm region, and the maximum blue shift of the defect peak in PL spectrum could reach 80 nm with the increase concentration of MAA. The absorption spectra and PL spectra on the surface of porous alumina thin film were used to further analyze the charge separation and capture of charge carriers. This novel organic‐inorganic ligand exchange method provides an effective strategy for regulating fluorescence and electron transfer, which could be used on biological, solar cells or other practical applications.

Syntheses of naphthyl-based quaternary ammonium surfactants and their catalytic properties in chloromethylation of naphthalene

Two naphthyl-based quaternary ammonium surfactants Naph-GS and Naph-MS were synthesized by reaction of bis(chloromethyl)naphthalene and chloromethyl naphthalene with N, N-dimethyl long-chain alkyl tertiary amine. The purified products were characterized by FT-IR and ESI-HRMS. The critical micelle concentration and surface tension (γCMC) at the critical micelle concentration (CMC) of Naph-MS and Naph-GS are 3.70 mmol/L, 27.90 mN/m; 0.89 mmol/L and 31.60 mN/m, respectively. The CMC of Naph-MS is about four times higher than that of Naph-GS. The sizes of most micelles of Naph-MS and Naph-GS aqueous solution at 1.1 CMC are both <1 nm. While at the concentration of 11 CMC, most of the Naph-MS, the Naph-GS micelles aggregate forming particles with an average size of 1.2 nm and 10 nm, respectively. The Naph-MS and Naph-GS were used to promote the chloromethylation reaction of naphthalene. The conversion of naphthalene was 77% when the reaction was catalyzed by Naph-MS (2.5 mol% of naphthalene at 48 mmol/L) at mole ratio of naphthalene/paraformaldehyde/NaCl/H2SO4 being 1.0:1.0:1.7:6.3 at 70 °C for 12 h. At the same condition, the conversion of naphthalene was 82% when the reaction was promoted by Naph-GS (0.53 mol% of naphthalene at 10 mmol/L). When the mole ratio of naphthalene/paraformaldehyde was increased to 1.25, the conversion of naphthalene increased to 90%, and the positioning selectivity (1-chloromethyl to 2-chloromethyl) is 94.8%. The gemini surfactant Naph-GS has better catalytic performance than conventional Naph-MS in the chloromethylation of naphthalene. The inorganic aqueous solution can be recycled by simple separation, and the conversion of naphthalene can still remain at 85% after 5 cycles.

Zirconia modified nanostructured MoO3 thin films deposited by spray pyrolysis technique for Cu/MoO3-ZrO2/p-Si structured Schottky barrier diode application

We report an inorganic aqueous solution route for pure molybdenum trioxide (MoO3) and zirconium oxide composite (MoO3-ZrO2) insulating layer of Cu/MoO3-ZrO2/p-Si metal-insulator-semiconductor structured Schottky barrier diodes. These composite films were coated by Jet Nebulizer Spray Pyrolysis techniques with a substrate temperature of 500 °C and analyzed using X-ray diffraction, Field emission scanning electron microscope, DC electrical conductivity and I–V characterization. These MoO3-ZrO2 films exhibited different crystal structures. Field emission scanning electron microscopes images displayed plate-like structure with improved grain size. The presence of Zr, Mo and O atoms were confirmed by energy dispersive x-ray spectrum. Optical studies shows the maximum absorption and higher optical badgap for (15 wt%) of Zr in MoO3. DC electrical studies recorded the maximum activation energy with minimum conductivity for Zr based composite films. Current - Voltage measurements were analyzed in both dark and illuminated conditions for Cu/MoO3-ZrO2/p-Si Schottky Barrier diodes. Minimum ideality factor (2.98) and maximum barrier height (0.664 eV) was obtained for 15 wt% of Zr composite thin films.

The aqueous chemistry of polonium (Po) in environmental and anthropogenic processes.

The longest-lived naturally occurring isotope of polonium is polonium-210, one of the daughters of uranium-238 (138 days half-life). As a daughter radionuclide of radon-222, polonium-210 can become enriched in pore fluids in U-bearing rocks, leading to contents in excess of 100 Bq.g-1 in some products from the mineral, coal, oil and gas industries (e.g., anode slimes in copper refinement; sludge from the oil and gas industry). Since 2006, IAEA recommendation limits require polonium and other radionuclides from the U- and Th-series decay to be regulated for products and wastes that contain >1 Bq.g-1, which results in the classification of large amounts of industrial products and waste as radioactive. To develop effective methods for polonium removal and/or control, it is necessary to acquire an understanding of its aqueous chemistry. Based on a review of available experimental data, we developed a self-consistent thermochemical model for polonium in inorganic aqueous solutions. Polonium exists mainly in two oxidation states in aqueous solutions: Po(IV) and Po(II). The importance of Po(II) is unique, as Te(II) or Se(II) complexes do not appear to play a significant role in aqueous solution at room temperature. The model is used to discuss polonium speciation in some environmental and process waters.

Assessment of Bentonite Compatibility with Salinity Using Centrifugation-Based Water Retention

Abstract A generalized centrifugation-based water retention (CWR) test has been developed to evaluate the chemical compatibility of geosynthetic clay liner bentonites with different inorganic aqueous solutions of various types and ionic strengths of two salts, NaCl and CaCl2, and to serve as a surrogate for the standard swell index (SI) test. The intention of this study is to provide the industry and researchers with a powerful, robust, and accurate method that fulfills the same pre-screening role as the SI test but is more efficient, quantifiable, and reproducible. The steps to optimize the centrifugation-based test are reported and discussed, and the effects of various parameters (e.g., g level, centrifugal duration, ionic strength of inorganic salts, etc.) on the water retention characteristics of bentonite are analyzed and evaluated. In general, water retention of bentonites decreased with increasing salt loads and centrifugal forces. Centrifugal duration (30 min versus 60 min) had little to no effect on the measured CWR values. The CWR strongly correlated with SI for the same samples, enabling predictions of SI of Na-bentonite in weak to strong saline solutions.

Good Lithium-Ion Insertion/Extraction Characteristics of a Novel Double Metal Doped Hexa-Vanadate Compounds Used in an Inorganic Aqueous Solution

We report a potassium doped NaV6O15 anode with enhanced electrochemical performance, used for aqueous rechargeable lithium ion battery. Different Na1–xKxV6O15 (x = 0, 0.1, 0.2, 0.3) compounds are prepared and characterized using X-ray diffraction patterns ensuring potassium doping. The electrochemical performances of the various potassium doped anodes NaV6O15, Na0.9K0.1V6O15, Na0.8K0.2V6O15, and Na0.7K0.3V6O15 are evaluated by cyclic voltammetry and galvanostactic charge/discharge methods. The results suggest that potassium-doping has a positive effect on the electrochemical performance of aqueous rechargeable lithium ion batteries. The anode Na0.8K0.2V6O15 is found to be optimized potassium doped anode materials for aqueous rechargeable lithium ion battery. The Na0.8K0.2V6O15 anode displays enhanced cycling and rate performances, an initial specific capacity of 218 mAhg–1, and 133 mAhg–1 is delivered after 50 cycles (61% capacity retention) at the current density of 100 mAg–1. The potassium doping has in...

Complexation of Eu(III), Pb(II), and U(VI) with a Paramecium glycoprotein: Microbial transformation of heavy elements in the aquatic environment

This study investigated the interaction of inorganic aqueous Eu(III), Pb(II), and U(VI) with Paramecium sp., a representative single-celled protozoan that lives in freshwater. Living and prekilled Paramecium cells were tested. The prekilled cells were killed with a fixative. After 24 h exposure of the cells to inorganic aqueous solutions containing Eu(III) or U(VI), analyses by microparticle-induced X-ray emission with a focused beam (<1 μm) did not detect Eu and U in the living cells, whereas Eu and U were detected in the prekilled cells. Size exclusion chromatography coupled with on-line ultraviolet–visible detection and elemental detection by inductively coupled plasma mass spectrometry of the aqueous phases collected after the living cell experiments revealed that a fraction of the Eu, Pb, and U in the aqueous phase bound to a large (ca. 250 kDa) Paramecium biomolecule and formed a metal-organic complex. The characteristics of the biomolecule were consistent with those of the soluble glycoproteins covering the surfaces of Paramecium cells. These results show that Paramecium cells transform inorganic aqueous Eu, Pb, and U to organic complexes. This paper discusses the relation between this novel complexation and the sorption of these heavy elements on Paramecium cells.

Investigation of the Use of an Inorganic Aqueous Solution in Copper-Made Phase-Change Heat Transfer Devices

A novel inorganic aqueous solution (IAS) is shown to have a better heat transfer performance than water when used as the working fluid in copper-made phase-change heat transfer devices. First, the physical properties of IAS are measured and compared to those of water. Another, a chemical analysis is performed, and the chemical reactions involved between IAS and the copper surface are listed and categorized by their contributions to the heat transfer performance. In addition, a capillary rise test is performed to show how each chemical contributes to the improvement of the surface wettability. Last, using IAS in copper-made phase-change heat transfer devices is discussed, and the main focus is how IAS improves the heat transfer performance by a smaller thermal resistance and a larger critical heat flux. The conclusion is validated by thermo-siphon tests at different inclination angles.

Investigation of the Use of an Inorganic Aqueous Solution in Aluminum-Made Phase-Change Heat Transfer Devices

An inorganic aqueous solution, known as IAS, has shown its compatibility with aluminum phase-change heat transfer devices. When using IAS in aluminum devices, aluminum prefers to react with the two oxidizers, permanganate and chromate, rather than water to generate a thin and compact layer of aluminum oxide, which protects the aluminum surface and prevents further reactions. In addition, an electrochemical theory of aluminum passivation is introduced, and the existence of an electrochemical cycle is demonstrated by an aluminum thermosiphon test. The electrochemistry cycle, built up by liquid back flow and tube wall, allows the oxidizers to passivate the aluminum surface inside the device without being directly in contact with it. However, failure was detected while using IAS in thermosiphons with air natural convection cooling. The importance of a continuous liquid back flow to aluminum passivation in phase-change heat transfer devices is pointed out, and a vertical thermosiphon test with natural convection cooling is used to demonstrate that a discontinuous liquid back flow is the main reason of the failures.

Passivation and Performance of Inorganic Aqueous Solutions in a Grooved Aluminum Flat Heat Pipe

Aluminum heat pipes have traditionally been incompatible with water and water-based fluids because they quickly react to generate noncondensable hydrogen gas (NCG). Two different inorganic aqueous solutions (IAS) are tested in a flat heat pipe (FHP). Grooved aluminum plates were used as the heat pipe wick and the tests were run with the heating section raised above the condenser. Compatibility between the working fluid and the aluminum heat pipe was established by running the device to dryout and observing thermal resistance results along the way. De-ionized (DI) water was also tested, as a baseline for comparison, to establish that it did indeed fail as expected. Operating performance of each mixture was obtained from zero heat input until dryout was reached for two angles of inclination. The data suggest that both IAS mixtures are compatible with aluminum heat pipes and exhibit performance similar to that of a copper and water heat pipe. It is demonstrated that IAS and aluminum heat pipes show potential for replacing existing copper and water devices for some applications and provide alternative options for heat pipe designers who value both the thermophysical property advantages of water and reduced weight of aluminum devices.

Precooled Aerosols Are Better Raindrop Nuclei

Cooling inorganic and organic aqueous solutions makes the particles into more robust seeds of clouds.

Energy characterisation of ultrasonic systems for industrial processes

Obtaining accurate power characteristics of ultrasonic treatment systems is an important step towards their industrial scalability. Calorimetric measurements are most commonly used for quantifying the dissipated ultrasonic power. However, accuracy of these measurements is affected by various heat losses, especially when working at high power densities. In this work, electrical power measurements were conducted at all locations in the piezoelectric ultrasonic system equipped with ½″ and ¾″ probes. A set of heat transfer calculations were developed to estimate the convection heat losses from the reaction solution. Chemical dosimeters represented by the oxidation of potassium iodide, Fricke solution and 4-nitrophenol were used to chemically correlate the effect of various electrical amplitudes and treatment regimes. This allowed estimation of sonochemical-efficiency (SE) and energy conversion (XUS) of the ultrasonic system. Results of this study showed overall conversion efficiencies of 60–70%. This correlated well with the chemical dosimeter yield curves of both organic and inorganic aqueous solutions. All dosimeters showed bubble shielding and coalescence effects at higher ultrasonic power levels, less pronounced for the ½″ probe case. SE and XUS values in the range of 10−10mol/J and 10−3J/J respectively confirmed that conversion of ultrasonic power to chemical yield declined with amplitude.

Reactive uptake of N&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;O&amp;lt;sub&amp;gt;5&amp;lt;/sub&amp;gt; to internally mixed inorganic and organic particles: the role of organic carbon oxidation state and inferred organic phase separations

Abstract. We measured N2O5 reactive uptake onto mixed organic/inorganic submicron particles using organic compounds with a variety of oxidation states (using mainly atomic O : C ratios as a proxy) and molecular weights. The organic mass fraction, organic molecular composition, and relative humidity (RH) were varied to assess their effects separately on the N2O5 uptake coefficient, γ(N2O5). At a constant RH, mixtures of organic components having an O : C &lt; 0.5 with ammonium bisulfate significantly suppressed the uptake of N2O5(g) compared to pure ammonium bisulfate, even at small organic mass fractions (e.g., ≤ 15%). The effect of the organic component became less pronounced at higher RH. In general, highly oxygenated organic components (O : C &gt; 0.8) had a smaller or even negligible impact on N2O5(g) uptake at all RHs probed; however, a few exceptions were observed. Notably, γ(N2O5) for mixtures of ammonium bisulfate with polyethylene glycol (PEG), PEG-300 (O : C = 0.56), decreased nearly linearly as the PEG mass fraction increased at constant RH until leveling off at the value measured for pure PEG. The response of γ(N2O5) to increasing PEG mass fraction was similar to that measured on ambient atmospheric particles as a function of organic mass fraction. The effects of the organic mass fraction on γ(N2O5), for mixtures having an O : C &lt; ~0.8, were best described using a standard resistor model of reactive uptake assuming the particles had an RH-dependent inorganic core–organic shell morphology. This model suggests that the N2O5 diffusivity and/or solubility in the organic layer is up to a factor of 20 lower compared to aqueous solution particles, and that the diffusivity, solubility, and reactivity of N2O5 within organic coatings and particles depend upon both RH and the molecular composition of the organic medium. We use these dependencies and ambient measurements of organic aerosol from the global aerosol mass spectrometry (AMS) database to show that the typical impact of organic aerosol components is to both uniformly decrease γ(N2O5), by up to an order of magnitude depending on the RH, organic mass fraction, and O : C ratio, and to induce a stronger dependence of γ(N2O5) upon RH compared to purely inorganic aqueous solutions.

PVDF surfaces with stable superhydrophobicity

Rough surfaces on pure polyvinylidene fluoride (PVDF) substrate were created via a simple roughening method using sandpaper. After modification with fluoroalkylsilane, the rough surface of PVDF exhibits superhydrophobicity, with contact angle larger than 160° and sliding angle lower than 5° not only for pure water but also for aqueous solutions under both acidic and basic conditions. In addition, the as-prepared surface possesses stable superhydrophobicity in various environments, such as ultrasonic cleaning, immersion in various organic solvents and inorganic aqueous solutions, temperature variation and UV irradiation. The stability of the low surface energy coating on the surface of PVDF was interpreted by the strong mechanical interlock interaction existing between the rough surface of PVDF and the continuous rough structures of the coating.

An Easy and Fast Procedure for the Determination of Ca, Cu, Fe, Mn, Mg, Na, K and Si in Biodiesel by ICP OES Using Emulsification as Sample Preparation Strategy

It is presented an alternative procedure for preparation of biodiesel samples for elemental determination by inductively coupled plasma optical emission spectrometry (ICP OES), based on the sample (10% m/v) emulsion formation with formic acid (15% v/v) and Triton X-100 (0.1% m/v). These concentrations were optimized and the stability of emulsified aqueous standards and samples was found to be of at least 3 h. Experimental conditions (1500 W of RF power and 0.5 L min-1 of Ar nebulizer flow rate) were optimized from those recommended by the equipment manufacturer, with a solution containing 10 mg L-1 of each analyte prepared with mineral oil in the same conditions of the emulsion. Matrix effects were investigated by observing the slopes of analyte addition curves for different biodiesel samples. Results showed that external calibration with inorganic aqueous standard solutions in the emulsion medium should be used. Limits of detection obtained (in mg kg-1) were 0.121, 0.008, 0.006, 0.001, 0.006, 0.071, 0.241 and 0.024 for Ca, Cu, Fe, Mn, Mg, Na, K and Si, respectively. The accuracy of the procedure for Ca, Mg, K and Na was assessed by the analysis of a multi-element standards B100 biodiesel (Conostan) and the recoveries ranged from 91 to 107%. The proposed procedure used low toxicity reagents and showed to be a simple and straightforward alternative of sample preparation for metal determination in biodiesel by ICP OES with limits of detection adequate for those analyses.

Electrochemical detection of arsenite with silver electrodes in inorganic electrolyte and natural system mixtures

The electrochemical detection of arsenite with silver wire (SWE) or silver disc (SDE) electrodes was carried out in inorganic aqueous solutions, which are similar to those found under natural conditions. Cyclic voltammetry (CV), linear sweep voltammetry (LSV) and anodic stripping voltammetry (ASV) were applied. The investigated factors were pH, nature and concentration of supporting electrolyte and deposition time and voltage for ASV. The changes in the As(III) anodic peak current and potential in standard solutions (e.g., 0.1 mol L-1 Na2SO4, NaNO3, HNO3 and H2SO4) were evaluated. The neutral and basic media of inorganic salts were found to enhance the silver electrode sensitivity more than the acidic media. Thus, it was possible to work in alkaline medium with increased sensitivity for As(III) (limit of detection of 90 ng L-1). The improved analytical response made this system comparable to a nanoarray electrode. As the range of use of these electrodes was wide, SWE (area of 6.47 mm²) was applied to monitor tap water using 0.1 mol L-1 Na2SO4 as supporting electrolyte to successfully detect quantities above 0.5 mg L-1 As(III).

Utilization of Advanced Working Fluids With Biporous Evaporators

A novel fluid for use as a working fluid in a heat pipe has been tested at UCLA. The fluid was discovered originally in use with a device consisting of a metal tube charged with the patented inorganic aqueous solution (IAS), which is evaporated when the tube is evacuated before use. According to the patent, this evaporation leaves a thin film that allows the tube to carry high heat flux loads with low temperature drop across the tube in a solid state mode. However, various experiments with these tubes have produced inconsistent results, and there are some questions as to whether the fluid is completely evaporated. The research on which this work is based is focused on testing whether the charging fluid will operate as the working fluid in a heat pipe, in order to determine the nature of the IAS fluid. A heat pipe apparatus was charged with a biporous wick in order to investigate if the fluid plays a role in heat transfer. There are extensive data for this experiment using water as the working fluid, which will be used to compare the two sets of results. Testing has shown a reduction of the superheat required to drive heat fluxes through a wick compared to water by approximately 40%. Some experiments have shown that the operating (temperature) range of the IAS is much larger than a standard heat pipe. It is theorized that the increase in performance of the IAS is due to an increased thermal conductivity of the wick and increased capillarity. If this fluid is proven to be effective, it would lead to more effective and tunable heat transfer devices.