Water activity data representation of aqueous solutions at 25°C

1974 ◽  
Vol 52 (3) ◽  
pp. 387-391 ◽  
Author(s):  
Tjoon-Tow Teng ◽  
Fabio Lenzi
Keyword(s):  
Aqueous Solutions ◽  
Water Activity ◽  
Data Representation ◽  
Activity Data

scholarly journals Model for estimating activity coefficients in binary and ternary ionic surfactant solutions

2020 ◽  
Vol 77 (4) ◽  
pp. 141-168
Author(s):  
Silvia M. Calderón ◽  
Jussi Malila ◽  
Nønne L. Prisle
Keyword(s):  
Aqueous Solutions ◽  
Water Activity ◽  
Activity Coefficients ◽  
Ternary Systems ◽  
Inorganic Salts ◽  
Ionic Surfactant ◽  
Activity Data ◽  
Chloride System ◽  
Wide Range ◽  
Sodium Decanoate

AbstractWe introduce the CMC based Ionic Surfactant Activity model (CISA) to calculate activity coefficients in ternary aqueous solutions of an ionic surfactant and an inorganic salt. The surfactant can be either anionic or cationic and in the present development, the surfactant and inorganic salts share a common counterion. CISA incorporates micellization into the Pitzer–Debye–Hückel (PDH) framework for activities of mixed electrolyte solutions. To reduce computing requirements, a parametrization of the critical micelle concentration (CMC) is used to estimate the degree of micellization instead of explicit equilibrium calculations. For both binary and ternary systems, CISA only requires binary experimentally-based parameters to describe water–ion interactions and temperature–composition dependency of the CMC. The CISA model is intended in particular for atmospheric applications, where higher-order solution interaction parameters are typically not constrained by experiments and the description must be reliable across a wide range of compositions. We evaluate the model against experimental activity data for binary aqueous solutions of ionic surfactants sodium octanoate and sodium decanoate, as common components of atmospheric aerosols, and sodium dodecylsulfate, the most commonly used model compound for atmospheric surfactants. Capabilities of the CISA model to describe ternary systems are tested for the water–sodium decanoate–sodium chloride system, a common surrogate for marine background cloud condensation nuclei and to our knowledge the only atmospherically relevant system for which ternary activity data is available. For these systems, CISA is able to provide continuous predictions of activity coefficients both below and above CMC and in all cases gives an improved description of the water activity above the CMC, compared to the alternative model of Burchfield and Wolley [J. Phys. Chem., 88(10), 2149–2155 (1984)]. The water activity is a key parameter governing the formation and equilibrium growth of cloud droplets. The CISA model can be extended from the current form to include the effect of other inorganic salts with the existing database of binary PDH parameters and using appropriate mixing rules to account for ion specificity in the micellization process.

The Water-activity of Supersaturated Aqueous Solutions of NaCl, KCl, and K2SO4 at 25°C

1975 ◽  
Vol 53 (20) ◽  
pp. 3133-3140 ◽  
Author(s):  
Fabio Lenzi ◽  
Tuong-Tu Tran ◽  
Tjoon-Tow Teng
Keyword(s):  
Aqueous Solutions ◽  
Water Activity ◽  
Aqueous Systems ◽  
Activity Data ◽  
Self Consistent ◽  
The Individual ◽  
Supersaturated Solutions

Reverse application of the Reilly–Wood-Robinson and Zdanovskii–Stokes–Robinson equations to the water-activity data of various ternary aqueous systems containing NaCl, KCl, K2SO4 as one of the components yields self-consistent estimates of the water-activity of binary aqueous supersaturated solutions of the individual salts; these can be further extended by curvilinear extrapolation to give: [Formula: see text] with A1 = −3.28806 × 10−2, A2 = 1.12512 × 10−4, A3 = −4.30034 × 10−4, A4 = 2.70506 × 10−5, A5 = 1.43435 × 10−6, A6 = 1.30209 ×10−7, A7 = −1.51941 × 10−8, A8 = 1.00520 × 10−9, A9 = −4.21593 × 10−10, A10 = 2.62532 × 10−11, valid to aw(NaCl) = 0.5422, [Formula: see text][Formula: see text]with B1 = −3.21884 × 10−2, B2 = 9.77773 × 10−4, B3 = −6.05349 × 10−4, B4 = 1.18422 × 10−4, B5 = −7.91572 × 10−6, B6 = −3.88125 × 10−8, B7 = 1.55125 × 10−8, valid to aw(KCl) = 0.7115, [Formula: see text][Formula: see text] with C1 = −4.16810 × 10−2, C2 = 1.16033 × 10−2, C3 = −4.80543 × 10−3, C4 = 7.15536 x 10−4, valid to [Formula: see text][Formula: see text]

A General Method of Calculating the Water Activity of Supersaturated Aqueous Solutions from Ternary Data

1973 ◽  
Vol 51 (16) ◽  
pp. 2626-2631 ◽  
Author(s):  
J. Sangster ◽  
T. T. Teng ◽  
F. Lenzi
Keyword(s):  
Aqueous Solutions ◽  
Water Activity ◽  
Binary Data ◽  
Solubility Limit ◽  
Activity Data ◽  
Binary Solutions ◽  
High Concentrations ◽  
Ternary Data ◽  
Supersaturated Solutions ◽  
General Method

Recently developed methods of predicting water activities of multicomponent aqueous solutions use binary data. At high concentrations these methods are limited inasmuch as they require binary data beyond the solubility limit of individual solutes. A method is proposed whereby ternary water activity data may be used to calculate water activities of supersaturated binary solutions. The new method is compared with two extrapolation procedures on a known system and gives the best agreement. Values of the water activities for supersaturated solutions of KNO3 (3.8 to 7.6 m) and K2SO4 (0.7 to 2.3 m) at 25 °C are obtained.

Vapour pressures of aqueous solutions of AgNO3 + TlNO3 by the static method at 98.5 °C

1977 ◽  
Vol 55 (10) ◽  
pp. 1713-1719 ◽  
Author(s):  
Marie-Christine Trudelle ◽  
Maurice Abraham ◽  
James Sangster
Keyword(s):  
Free Energy ◽  
Aqueous Solutions ◽  
Water Activity ◽  
Mole Fraction ◽  
Vapour Pressure ◽  
Excess Free Energy ◽  
Static Method ◽  
Present System ◽  
Activity Data ◽  
Bet Isotherm

Vapour pressures of the system (Ag,Tl)NO3 + H2O have been measured at 98.5 °C by the static method over the complete concentration range for Ag/Tl mole ratio = 1.14. The water activity data can be represented by a modified BET isotherm in the range 0.1 < aw < 0.7. The derived BET constants indicate that the salts in this system are very weakly hydrated, probably less so than (for example) CsNO3. The linearity of vapour pressure with water mole ratio RH, found previously by Tripp and Braunstein for (Li,K)NO3 + H2O, is absent in the present system. The Henry's law constant for water dissolved in molten (Ag,Tl)NO3 has been deduced. The excess free energy of the system is positive at all concentrations and shows a maximum of 117 cal/mol at water mole fraction 0.66.

scholarly journals Physical properties of iodate solutions and the deliquescence of crystalline I<sub>2</sub>O<sub>5</sub> and HIO<sub>3</sub>

2010 ◽  
Vol 10 (24) ◽  
pp. 12251-12260 ◽  
Author(s):  
R. Kumar ◽  
R. W. Saunders ◽  
A. S. Mahajan ◽  
J. M.C. Plane ◽  
B. J. Murray
Keyword(s):  
Water Activity ◽  
Temperature Dependent ◽  
Activity Data ◽  
Gas Phase Chemistry ◽  
Activity Density ◽  
Phase Chemistry ◽  
First Time ◽  
Measured Water ◽  
Complex Ion

Abstract. Secondary aerosol produced from marine biogenic sources in algal-rich coastal locations will initially be composed of iodine oxide species, most likely I2O5, or its hydrated form HIO3, formed as a result of iodine gas-phase chemistry. At present, there is no quantitative hygroscopic data for these compounds and very little data available for iodate solutions (HIO3 and I2O5 share a common aqueous phase). With increased interest in the role of such aerosol in the marine atmosphere, we have conducted studies of (i) the deliquescence behaviour of crystalline HIO3 and I2O5 at 273–303 K, (ii) the efflorescence behaviour of aqueous iodate solution droplets, and (iii) properties (water activity, density, and viscosity) of subsaturated and saturated iodate solutions. The deliquescence of I2O5 crystals at 293 K was observed to occur at a relative humidity (DRH) of 80.8±1.0%, whereas for HIO3, a DRH of 85.0±1.0% was measured. These values are consistent with measured water activity values for saturated I2O5 and HIO3 solutions at 293 K of 0.80±0.01 and 0.84±0.01 respectively. At all temperatures, DRH values for HIO3 crystals were observed to be higher than for those of I2O5. The temperature-dependent DRH data, along with solubility and water activity data were used to evaluate the enthalpy of solution (ΔHsol) for HIO3 and I2O5. A ΔHsol value of 8.3±0.7 kJ mol−1 was determined for HIO3 which is consistent with a literature value of 8.8 kJ mol−1. For I2O5, we report for the first time its solubility at various temperatures and ΔHsol = 12.4±0.6 kJ mol−1. The measured water activity values confirm that aqueous iodate solutions are strongly non-ideal, consistent with previous reports of complex ion formation and molecular aggregation.

scholarly journals Sorption isotherms of ingredients and diets for poultry

2020 ◽  
Vol 9 (9) ◽  
pp. e828997729
Author(s):  
Carina Sordi ◽  
Fernando de Castro Tavernari ◽  
Diego Surek ◽  
Laudete Maria Sartoretto ◽  
Tiago Goulart Petrolli ◽  
...  
Keyword(s):  
Water Activity ◽  
Dry Matter ◽  
Choline Chloride ◽  
Sorption Isotherms ◽  
Vitamin Supplement ◽  
Mineral Supplement ◽  
Activity Data ◽  
Nutritional Values ◽  
Hygroscopic Behavior

This study aimed to determine sorption isotherms of ingredient and poultry diet. The samples were encapsulated in capsules and dehydrated by oven-drying in a desiccator for more than 24 hours. The samples were transferred to desiccator containing water in the base and placed in the oven, with one sample of each material being removed at incremental intervals. The sample was weighed and for determination of water activity and for dry matter. The moisture and water activity data were evaluated by eight mathematical models. The GAB mathematical model fitted the experimental data to constitute the isotherm for each material. Type II sorption isotherms were found, except for BHT: demonstrated values that did not fit the isotherm determination. The hygroscopic behavior of the ingredients in ascending order were: L- threonine, limestone, BHT, DL- methionine, L-valine, L- tryptophan, phosphate, kaolin, vitamin supplement, salt, mycotoxin deactivator, pelleted rooster diet, mash rooster diet, mash layer diet, pelleted layer diet, corn, bacitracin zinc, vitamin mineral supplement, phytase, rice bran, wheat bran, mineral supplement, soybean meal, coccidiostat, L- Lysine HCl and choline chloride. Ingredients and diets have different hygroscopic behavior: can lead to deterioration and low accuracy in nutritional values of diet, since formulation is based on as-is fed basis.

A review, analysis and extension of water activity data of sugars and model honey solutions

2020 ◽  
Vol 326 ◽  
pp. 126981
Author(s):  
Balaji Subbiah ◽  
Ursula K.M. Blank ◽  
Ken R. Morison
Keyword(s):  
Water Activity ◽  
Activity Data ◽  
Review Analysis
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