CH3COONa Solutions Research Articles

Equilibrium vapor pressure of aqueous sodium acetate and potassium acetate solutions used as working fluids in frost-free air–source heat pumps at 263–328 K

Aqueous solutions of sodium acetate (CH3COONa) and potassium acetate (CH3COOK) are considered effective alternative heat exchange media for frost-free air–source heat pumps (FFASHPs) owing to the low corrosiveness, low viscosity, and low cost. Equilibrium vapor pressure is the most crucial property that characterizes freezing point and latent heat transfer. However, studies on this property, especially in subzero temperature ranges are scarce. This study was conducted to experimentally investigate the equilibrium vapor pressure of CH3COONa and CH3COOK solutions. The developed apparatus and procedures were based on the static method, and validated by evaluating the vapor pressure of distilled water, n-heptane, and calcium chloride (CaCl2) aqueous solution. Their average absolute deviations were within 1.94%. As the temperature increased from 263 to 328 K and solute concentration increased from 9.27 to 33.81 wt%, 124 data points of the vapor pressure of the CH3COONa and CH3COOK solutions were obtained, ranging from 0.2759 to 13.2608 kPa. Modified Antoine equation and ion interaction (Pitzer) model were established for correlation of the experimental data. The average absolute deviations of the CH3COONa and CH3COOK solutions produced by Antoine equation were 2.08 and 2.48%, respectively. Those produced by Pitzer model further decreased to 1.36 and 1.45% due to the import of osmotic coefficient and the accuracy improvement. Furthermore, according to the experimental and calculation results, the vapor pressure of the CH3COONa solution was lower than that of the CH3COOK solution. Therefore, under the same antifreezing conditions, the CH3COONa solution facilitates latent heat absorption from ambient air, while the CH3COOK solution is conducive to achieve regeneration. The results of this study provide foundational data for the vapor pressure of the two solutions and can promote their application in FFASHPs.

Effect of external magnetic field on terahertz transmission characteristics of electrolyte solution based on microfluidic technology

In this study, the effect on the terahertz (THz) transmission characteristics was investigated by varying the constant magnetic field time at both ends of the liquid sample (deionized water, CuSO4, CuCl2, (CH3COO) 2Cu, Na2SO4, NaCl, CH3COONa solution). The results show that the transmission intensity of THz waves decreases with the increase of solution residence time in a constant magnetic field. It is inferred that the magnetic field increases the number of hydrogen bonds in the solution, enhances the role of hydrogen bonds, and weakens the intensity of THz transmission spectra.

Terahertz spectra of electrolyte solutions under applied electric and magnetic fields

Most biomolecules require an aqueous environment to fully exert their biological activity. However, the rotation mode, vibration mode, and energy associated with the hydrogen bonding network of water are in the terahertz band, resulting in strong absorption. Therefore, it is difficult to detect liquid biological samples using the terahertz technology. Here, a high-transmittance double-layer microfluidic chip was prepared using a cycloolefin copolymer material with high transmittance of terahertz waves. Combined with terahertz time-domain spectroscopy, the terahertz spectral characteristics of deionized water, NaCl, NaCO3, and CH3COONa solutions were studied. The changes in the terahertz transmission intensity of these electrolyte solutions under constant electric and magnetic fields were measured. The results show that the terahertz spectra of different sodium salt solutions with the same concentration of 0.9 mol/L are different. Furthermore, the terahertz absorption coefficients of the different electrolyte solutions gradually decrease with the increase of their residence time under the electric field, which is contrary to the results obtained under the external magnetic field. This study provides a new idea for the detection of sodium salt solution and lays a foundation for the development of THz technology.

Fiber-optic surface plasmon resonance-based sensor with AZO/Au bilayered sensing layer

We describe a surface plasmon resonance-based fiber sensor based on a side-polished graded-index multimode fiber, in which an Al-doped zinc oxide/gold (AZO/Au) bilayer is deposited on the side-polished surface of the fiber core to improve the detection sensitivity of the device. The AZO/Au layer is used as the active sensing member of the device with a combination of a 75-nm-thick AZO layer and a 40-nm-thick Au layer. Such a device is then applied to the concentration measurement of CH3COONa solutions, as an example showing a good response to concentration variation. The results indicate that the additional AZO layer in the active sensing member may lead to higher detection sensitivity and greater measurement stability in the measurements of solution concentration.

Cleaning and regeneration of periphyton biofilm in surface water treatment systems

The fouling of periphyton biofilm is a common problem associated with surface water treatment systems. In this study, sulfuric acid (H2SO4), sodium acetate (CH3COONa) and ethylenediamine tetra-acetic acid (EDTA) solutions were sequentially used to clean periphyton biofilms collected from a surface water treatment system. The results showed that the sequential addition of H2SO4 and CH3COONa solutions could accelerate the exfoliation of the fouled periphyton biofilm, while the addition of EDTA solution could regenerate the periphyton biofilm. However, the addition of H2SO4 and CH3COONa solution might negatively affect the bacterial community structure, while the addition of EDTA solution facilitated improvement of the community structure. The combined effect of cleaning and regeneration of periphyton biofilm has significantly improved the removal efficiencies of chemical oxygen demand (COD), total phosphorus (TP), total nitrogen (TN) and ammonia (NH4-N), by 19, 20, 23 and 22%, respectively. The removal processes of COD, TP, TN and NH4-N by the cleaned biofilm were fitted to power regression curves, while those by the control biofilm during the removal process were fitted to polynomial regression curves. These systemic results indicate that the sequential addition of H2SO4, CH3COONa and EDTA solution is able to clean fouled periphyton biofilm and to enhance the efficiency of surface water treatment systems.

Development of a Novel Composite Material with Carbon Nanotubes Assisted by Self-Assembled Peptides Designed in Conjunction with β-Sheet Formation

A novel composite material is developed with single-walled carbon nanotubes (SWCNTs) and artificially designed peptides, and its chemical and physicochemical characteristics are evaluated with an aim toward biomedical application. The peptides were designed to form a β-sheet structure that would be suitable for wrapping SWCNTs. The complex of SWCNTs and peptide (SWCNT-peptide) showed good dispersibility in aqueous media and was considerably stable even in the absence of an excess amount of peptide in the media. The formation of SWCNT-peptide was confirmed by its performance in water, atomic force microscopy and transmission electron microscopy observation, and molecular modeling. The possibility of introducing various functions to SWCNT-peptide was also demonstrated by several methods, such as introduction of special amino acids, chemical modification, and additional complex formation based on electrostatic interaction. These results suggest the potential of the SWCNT-peptide complex as a molecular platform on which a desirable structure and/or function can be constructed for biomedical and industrial application.

Extraction of Ca (II) and Mg (II) from Hydrochloric Acid Solutions by N, N-Dioctyl-1-Octan Ammonium Chloride in Methyl Isobutyl Ketone

Problem statement: Amines as organic molecules are able to form complexes with metals ions and this is the reason why we can use them to extract metals ions from hydrometallurgical solutions. Approach: Based on that, we have investigated the extraction of Calcium and Magnesium with N, N-dioctyl-1-octan ammonium chloride from the mixture of elements (Ca and Mg) prepared in artificial manner. We have investigated the influen ce of HCl concentration and salts (NaCl, NaI and CH 3COONa) concentration in extraction of two elements (Ca and Mg) from water solutions. All extractions were done from HCl water solutions with c = 3, 6 and 9 mol L -1 and in presence of NaCl, NaI and CH 3COONa salts, which we prepared in different concentrations. Results: Extraction of Calcium from NaCl solution move from 18-30%, from NaI solution 55-77% and from CH 3COONa solution 50-71%. Extraction of Magnesium from NaCl solution move from 3-12%, from NaI solution 0-11% and from CH 3COONa solution 0-8%. Conclusion: As optimal condition to separate Calcium from Magnesium is the extraction of Calcium from HCl solution with concentration 9 mol L -1 in presence of NaI with concentration of 60 g L -1 . Using these condition 77% of Calcium was in organic

Extraction of Ca(II) and Mg(II) from Hydrochloric Acid Solutions by N,N-Dioctyl-1-Octanamine in Methyl Isobutyl Ketone

Problem statement: Amines as organic molecules are able to form complexes with metals ions and this is the reason why we can use them to extract metals ions from hydrometallurgical solutions. Approach: Based on that, we have investigated the extraction of Calcium and Magnesium with N,N-dioctyl-1-octammine from the mixture of elements prepared in artificial manner. We investigated the influence of HCl concentration and salts (NaCl, NaI and CH3COONa) concentration in extraction of two elements (Calcium and Magnesium) from water solutions. All extractions were done from HCl water solutions with c = 3, 6 and 9 mol L-1 and in presence of NaCl, NaI and CH3COONa salts, which we prepared in different concentrations. Results: Extraction of Calcium from NaCl solution move from 50-75%, from NaI solution 0-90% and from CH3COONa solution 37-81%. Extraction of Magnesium from NaCl solution move from 0-10%. In solution of NaI we can not extract the Magnesium and from CH3COONa solution the extraction of magnesium moves from 0-30%. Conclusion: As optimal condition to separate Calcium from Magnesium is the extraction of Calcium from HCl solution with concentration 9 mol L-1 in presence of NaI with concentration of 60 g L-1. Using these condition 90% of Calcium was in organic phase and all of magnesium remains in water phase.

Pressure-induced helix—coil transition of poly-l-glutamic acid in water

The pressure effect on the helix-coil transition of aqueous poly-L-glutamic acid sodium salt (PLGA-Na) solutions was investigated by FT-IR spectroscopy. From the analysis of the amide I' band, the peak at 1637 cm-1 corresponding to the solvated α-helix structure increases with increasing pressure. The solvated α-helix structures of oligopeptides and proteins are stabilized upon compression. On the other hand, the peak intensities at 1710 and 1565 cm-1 corresponding to the C=O stretching mode of the COOH group and the C—O stretching mode of the COO-group of the side chain do not change with the pressure. According to high-pressure Raman study for the condensed aqueous CH3COONa solution, the pressure-induced dissociation of CH3COONa is found to be small. This result is qualitatively consistent with that of the side chain of PLGA-Na. The small pressure dependences of the side chain of PLGA-Na may be due to the high salt concentration in the solutions We have determined the difference in the partial molar volumes (PMV) between the α-helix and random coil structures of PLGA-Na at pD 5.0 to be +10.68±0.46 cm3/mol from the pressure dependence of the band intensities. The positive volume change of helix-coil transition of PLGA-Na is qualitatively consistent with the recent result of the volume change accompanying the helix—coil transition of PLGA (Noudeth G D et al, 2003 Biopolymers 70 563.).

Sono-electroplating of Tin Film From Ti(IV)-EDTA Bath

SnCl4 and EDTA-4Na were dissolved in a 2 mol/dm3 CH3COOH - 2 mol/dm3 CH3COONa buffer solution, and was adjusted to pH4.1 by adding 2 mol/dm3 CH3COOH or 2 mol/dm3 CH3COONa solutions. 100 cm3 of the electrolyte was used. In the stationary state, Sn film was not deposited below 100 mA/cm2, and Sn film deposited in the range of 200 to 1000 mA/cm2. However, thickness was not obtained 1 μm. In the sonication, electrodeposited film obtained 5 ∼ 20 μm in the range of 200 to 1000 mA/cm2. Electrodeposition was carried out smoothly, because the mass transfer accelerated with ultrasonic agitation and Sn ion was supplied to electrode surface. Best conditions of sono-electroplating were 0.10 mol/dm3 SnY, pH 4.0, 298 K and 300 mA/cm2. The mass transfer and crystallization processes were most affected with micro-jet and shock wave pressure in the range of 200 ∼ 400 mA/cm2. Exchange current density and reaction rate constant in the sonication increased compared with that in the stationary and vibration states. As for this, an electron reaction becomes fast by the micro-jet or shock wave pressure. Reduction became difficult to break out as sonication was with powerful agitation. The deposited film was smooth and dense surface in the sonication compared with that in the stationary states by the shock wave pressure. [DOI: 10.1380/ejssnt.2006.574]

Change in Sorption Characteristics of Uranium during Crystallization of Amorphous Iron Minerals

Sorption behavior of uranium (VI) during crystallization of amorphous iron (A.Fe) minerals to crystalline iron (C.Fe) minerals have been investigated. Two different sorption conditions are applied for the experiments. One is the condition in which uranium is sorbed on A.Fe minerals before the crystallization (dynamic condition). The other is the condition in which uranium is sorbed on the A.Fe minerals and C.Fe minerals of goethite (static condition). Associations of uranium with the iron minerals are examined by a selective extraction test using a 1 M CH3COOK solution at pH 7, 1 M CH3COONa solution at pH 5 (Morgan's solution), and TAO solution (10.9g.l−1 oxalic acid+l6.1g.l−1 ammonium oxalate).Under the static condition, the fraction of uranium desorbed by a 1 M CH3COOK solution at pH 7 from A.Fe minerals is lower than that from goethite. And all of uranium are desorbed by the TAO solution from both A.Fe minerals and goethite. Contrary, under the dynamic condition, fractional uranium is remained after the TAO solution extraction. The fractional uranium remained after the TAO solution extraction from the iron minerals increases with increase in the crystallinity of the iron minerals. The concentrations of uranium in the solutions are less than 1%. These show that during the crystallization of amorphous to crystalline iron minerals most of uranium associated with the amorphous iron minerals is not released into the solution, and some fractional uranium move to be fixed to crystalline iron minerals.

Change in Sorption Characteristics of Uranium during Crystallization of Amorphous Iron Minerals.

Sorption behavior of uranium (VI) during crystallization of amorphous iron (A.Fe) minerals to crystalline iron (C.Fe) minerals have been investigated. Two different sorption conditions are applied for the experiments. One is the condition in which uranium is sorbed on A.Fe minerals before the crystallization (dynamic condition). The other is the condition in which uranium is sorbed on the A.Fe minerals and C.Fe minerals of goethite (static condition). Associations of uranium with the iron minerals are examined by a selective extraction test using a 1 M CH3COOK solution at pH 7, 1 M CH3COONa solution at pH 5 (Morgan's solution), and TAO solution (10.9g.l−1 oxalic acid+l6.1g.l−1 ammonium oxalate). Under the static condition, the fraction of uranium desorbed by a 1 M CH3COOK solution at pH 7 from A.Fe minerals is lower than that from goethite. And all of uranium are desorbed by the TAO solution from both A.Fe minerals and goethite. Contrary, under the dynamic condition, fractional uranium is remained after t...

Enhancement in Diffusion of Electrolyte through Membrane Using Ultrasonic Dialysis Equipment with Plane Membrane

Application of ultrasound to accelerate the dialysis separation of electrolytes through a membrane was studied with ultrasonic dialysis equipment. The experiments were conducted with cellophane membrane and KCl solution, CH3COONa solution, and a mixture of KCl and saponin solutions. It was found that the diffusion velocity of electrolyte through a membrane with ultrasonic irradiation is faster than that without ultrasonic irradiation, and it increases with acoustic pressure. It has become clear that the reasons for enhancement caused by ultrasound are increase in liquid particle velocity and diffusion coefficient due to ultrasonic vibration. It was confirmed that the permeability of the membrane was not degraded by ultrasound in the ranges of acoustic pressure and irradiation time in this study.

The effect of anodic polarization on the ambient creep of brass

The effect of anodic and cathodic polarizations on the ambient creep of brass in 3.5% NaCl and CH 3COOH + CH 3COONa solutions has been investigated. The results showed that the creep rate in both solutions increased linearly with the increase of the anodic current density and was approximately inversely proportional to the square of the radius of the specimen. The dε/dt in 3.5% NaCl solution was much higher than that in the CH 3COOH + CH 3COONa solution at the same anodic current density. The creep rate resulting from dislocation climb induced by vacancy supersaturation during the anodic polarization has been calculated as follows: dϵ dt = K βi r 2 where K = 8 παMϱD s ΔtΔr/ C 0 dFZ ln ( R/ b), and β is a constant related to the degree of de-alloying. The experimental data support the proposed mechanism. Cathodic polarization could also increase the ambient creep of brass by a mechanism related to hydrogen-facilitated local plastic deformation.

An ellipsometric investigation of adsorbed layers on platinum electrodes at high anodic potentials

Ellipsometric measurements have been made of the films formed at high potentials on Pt in H2SO4 and CH3COOH+CH3COONa solutions. They confirm the coulometric results of Biegler and Woods that there is a limiting amount of adsorbed material at potentials above 2V (vs. RHE). The optical properties of the film formed in H2SO4 appear to be constant throughout the growth of the film whereas those of the film formed in acetate buffer vary during its growth. This demonstrates that acetate is incorporated in the film. This incorporation causes a lowering of the imaginary part of the refractive index which may be related to the inhibiting properties of the film.

An ellipsometric investigation of adsorbed layers on platinum electrodes at high anodic potentials

Ellipsometric measurements have been made of the films formed at high potentials on Pt in H2SO4 and CH3COOH+CH3COONa solutions. They confirm the coulometric results of Biegler and Woods that there is a limiting amount of adsorbed material at potentials above 2V (vs. RHE). The optical properties of the film formed in H2SO4 appear to be constant throughout the growth of the film whereas those of the film formed in acetate buffer vary during its growth. This demonstrates that acetate is incorporated in the film. This incorporation causes a lowering of the imaginary part of the refractive index which may be related to the inhibiting properties of the film.

Studies on the Ferreous Coating Formation in Roots of Rice Plants : (V) Ferreous coating formation in plants grown under abnormal conditions

As is previously reported, we have made clear that; (1) Ferreous coating formation (F. C. F.) in roots of rice plants proceeded parallely with nutrients absorption (N, P, and K) and production of the whole dry weigtht, (2) F. C. F. was closely correlated with the oxidation and sorption of Fe++ in media by roots, (3) Ferreous coating was mainly made with Fe++ oxidized and sorbed by roots and (4) The okidation and sorption of Fe++ were also influenced by Fe++ concentration in media. So far as it was concerned, physiological activities conducted by plant from the begining to a certain period of the growth may be proportionally recorded by F. C. F. measured at that period. This paper dealt with how F. C. F. is affected when plants are grown under abnormal conditions. Experiments are consisted of those mentioned below; (A) Effects of defoliation, (B) the same of leaf-blast infection, (C) the same of different soil temperatures, (D) the same of soils artificially deoxidized and (E) the same of nutrient deficiencies upon F. C. F., Fe++ oxidation and sorption in roots. F. C. F. in roots were washed away by 0.5 N-HCl and then colorimetrically determined by O-phenanthroline method. Fe++ oxidation and sorption by roots were estimated by determining concentration of Fe++ remained in FeSO4 solution, in which roots to be tested were soaked for 24 hrs. In addition, Fe++ concentrations in soils were also colorimetrically measured in filtrates, after soils were shaken with 1M CH3COONa solution. Main results obtained are as follows: (A) According to the grades of defoliation, F. C. F. in roots were either increased or decreased against non-defoliated (Fig. 1). The same resulted in Fe++ oxidation and sorption by roots (Fig. 2). In testing these physiological changes (Fig. 3), a temporaly rise of activities was found in defoliated plots. (B) When plants were infected by leafblast, F. C. F. in roots was also increased (Fig. 4). (C) The higher the soil temperature, the more F. C. F. in roots and Fe++ in soils were produced (Fig. 5). From this fact, F. C. F. in roots may be determined by amounts of Fe++ in soils. But as illustrated in Fig. 6, when Fe++ oxidation and sorption were measured, the higher temperature plot indicated higher physiological activities in contrast to the lower temperature and then activities decreased up to nearly equal values. From these it is clear that not only Fe++ amounts in soils but also the temperature affected F. C. F. in roots. (D) In artificially deoxidized soils, F. C. F. in roots of two varieties were similarly increased, notwithstanding the reduced plant growth (Fig. 7). (E) Nutrient deficiencies such as -N and -P made Fe++ oxidation and sorption in roots more active, but -K plot less active against complete nutrients plot (Fig. 8). This fact was obtained by using 30 days old seedling, but it was quite reverse when younger plants were used (Fig. 9). When abnormal conditions as mentioned above were given to plants, certain kinds of physiological activation or retardation may occur in infected or damaged parts, from where those effects may reach other parts, for instance, from top to roots. These facts were already recognized by some workers, just as activated or inactivated respiration in roots due to defoliation and others. From our results we can make an assumption again that such physiological changes happened in top or roots due to treatments may be recorded in the form of ferreous coating.