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Platinum group elements are invaluable tracers for planetary accretion and differentiation and the formation of PGE sulfide deposits. Previous laboratory determinations of the sulfide liquid–basaltic melt partition coefficients of PGE (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${D}_{PGE}^{SL/SM}$$\end{document}DPGESL/SM) yielded values of 102–109, and values of >105 have been accepted by the geochemical and cosmochemical society. Here we perform measurements of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${D}_{Pt,\,Pd}^{SL/SM}$$\end{document}DPt,PdSL/SM at 1 GPa and 1,400 °C, and find that \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${D}_{Pt,\,Pd}^{SL/SM}$$\end{document}DPt,PdSL/SM increase respectively from 3,500 to 3.5 × 105 and 1,800 to 7 × 105, as the Pt and Pd concentration in the sulfide liquid increases from 60 to 21,000 ppm and 26 to 7,000 ppm, respectively, implying non-Henrian behavior of the Pt and Pd partitioning. The use of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${D}_{Pt,\,Pd}^{SL/SM}$$\end{document}DPt,PdSL/SM values of 2,000–6,000 well explains the Pt and Pd systematics of Earth’s mantle peridotites and mid-ocean ridge basalts. Our findings suggest that the behavior of PGE needs to be reevaluated when using them to trace planetary magmatic processes., Platinum group elements are used as tracers for planetary and PGE sulfide deposit formation. Here, the authors, through the measurements of Pt and Pd partition coefficients between sulfide liquid and basaltic melt, demonstrate that the partitioning of Pt and Pd does not obey Henry’s law.

Modified stepwise model of gas sorption process with finely dispersed water flow. The sorption model allows forecasting the intensity of hazardous gases deposition with adequate for the emergency recovery conditions accuracy using minimum input parameters. This allows using the sorption model under the conditions of emergency and increasing the forecasting promptness. Use of chemical neutralizer is proposed to increase the effectiveness of chlorine hazardous gas deposition. Use of sodium hydroxide is proposed as the chlorine chemical neutralizer, which is easily dissolved in water, non-toxic and easy to store. An experimental laboratory facility was developed and created with the purpose of experimental verification of the sorption processes, which allows researching the sorption processes by liquid aerosols within a wide range of dispersity. Adequacy of the existing models as well as the modified one was verified experimentally. The verification results showed a 5% indicator of the theoretical and experimental results compliance.

Deep eutectic solvents (DES) are compounds of a hydrogen bond donor (HBD) and a hydrogen bond acceptor (HBA) that contain a depressed melting point compared to their individual constituents. DES have been studied for their use as carbon capture media and biogas upgrading. However, contaminants’ presence in biogas might affect the carbon capture by DES. In this study, conductor-like screening model for real solvents (COSMO-RS) was used to determine the effect of temperature, pressure, and selective contaminants on five DES’ namely, choline chloride-urea, choline chloride-ethylene glycol, tetra butyl ammonium chloride-ethylene glycol, tetra butyl ammonium bromide-decanoic acid, and tetra octyl ammonium chloride-decanoic acid. Impurities studied in this paper are hydrogen sulfide, ammonia, water, nitrogen, octamethyltrisiloxane, and decamethylcyclopentasiloxane. At infinite dilution, CO2 solubility dependence upon temperature in each DES was examined by means of Henry’s Law constants. Next, the systems were modeled from infinite dilution to equilibrium using the modified Raoults’ Law, where CO2 solubility dependence upon pressure was examined. Finally, solubility of CO2 and CH4 in the various DES were explored with the presence of varying mole percent of selective contaminants. Among the parameters studied, it was found that the HBD of the solvent is the most determinant factor for the effectiveness of CO2 solubility. Other factors affecting the solubility are alkyl chain length of the HBA, the associated halogen, and the resulting polarity of the DES. It was also found that choline chloride-urea is the most selective to CO2, but has the lowest CO2 solubility, and is the most polar among other solvents. On the other hand, tetraoctylammonium chloride-decanoic acid is the least selective, has the highest maximum CO2 solubility, is the least polar, and is the least affected by its environment.

Experiments were conducted for developing an on board MOFs hydrogen storage system by cryo-adsorption in terms of adsorption equilibrium and charge/discharge characteristic of the adsorbent bed. MIL-101 was synthesized by hydrothermal method, the expanded natural graphite (ENG) and a honeycomb heat exchanging device were then introduced for monolith and heat conducting enhancement. Structural characterization and measurement of thermal conductivity were performed on the MIL-101 and its composites synthesized by mixing ENG with different mass ratios. Adsorption equilibrium data of hydrogen on the MIL-101 and MEI-01 (composite formed by adding ENG with a mass ratio 0.1) were measured at a temperature-pressure range from 77.15K to 87.15 K and 0–6 MPa. Accuracies of results predicted by Langmuirian equations were compared, Toth equation and Henry law were then employed to calculate the isosteric heat of hydrogen adsorption. Charge and discharge tests were conducted under the flow rate 20 L · m i n − 1 on a 3.2 L conformable vessel respectively filled MIL-101, MIL-101+honeycomb heat exchanging device and MEI-01. It shows that the isosteric heats on two samples are similar and are about 3.1 kJ · m o l − 1 − 7.4 kJ · m o l − 1 ; the honeycomb heat exchanging device is better on weakening the thermal effect of the adsorbent bed than adding the ENG. It suggests that employing a conformable shape vessel equipped with a honeycomb heat exchanging device is a feasible solution to an on board MOFs hydrogen storage system.

Room-temperature ionic liquids offer a potential technological approach for propellant production on Mars using in situ resources. These unique salts can be employed to preferentially capture carbo...

In mid-ocean ridge hydrothermal systems the fluid redox state is controlled by oxidation of ferrous iron in the host rock and generation of aqueous hydrogen, H2(aq). A quantitative interpretation of redox state requires conversion of H2(aq) concentrations to H2 fugacity, f H2. Here we present the results of hydrothermal experiments that calibrate the f H2-concentration relationship in saline hydrothermal fluids, YH2-Cl. H2(aq) concentrations were measured between 400 and 500 °C, 210 and 510 bar, in both single-phase fluids and low-density vapors in the KCl-H2O system. The assemblage hematite-magnetite was used to buffer f H2. Values of YH2-Cl are well above unity and decrease as temperature increases. Along isotherms YH2-Cl decreases as the fluid density decreases. At 400 °C, 330 bar and 1000 mmol/kg KCl YH2-Cl is 316 bar/molal and decreases to 4 bar/molal at 500 °C, 400 bar and 33 mmol/kg KCl. In combination with previous determination of H2S(aq) solubility at hydrothermal conditions, the data presented here permit calculation of the redox conditions of natural vent systems. Redox conditions calculated for the basalt-hosted Piccard hydrothermal field suggest amphibolite facies mineral assemblages are present at depth, consistent with the extremely hot temperatures (>500 °C) inferred from analysis of other aspects of vent fluid chemistry (e.g., Cl and SiO2). Piccard may be the first location of active venting that records, through its composition, evidence for an alteration assemblage that had been previously observed only in fossilized submarine hydrothermal systems.

The thermodynamic property surfaces such as enthalpy and entropy of an adsorbate + adsorbent systems are essential for designing adsorption-assisted thermal compression, gas storage, separation, and other applications. This paper presents the enthalpy (∆ho) and the entropy (∆so) of the adsorbent-adsorbate system under the barrier of Henry's law region. Hence Henry's law coefficient and Gibbs analogy are applied to formulate the adsorption driving force (∆go). To justify the proposed formulation, the initial adsorption phenomena (at pressure, P → 0) of C2H5OH, CO2, CH4, N2, H2O, R125, R134a, R152a, and R1234yf on graphite/MOFs (such as Zr-MOF-801, Mg-MOF-74, and Al-Fumarate) are considered. It is found that the adsorption driving force is linked with the pore structure of adsorbent materials. We employ experimentally measured isotherms data to calculate the adsorption driving force, ∆go for various adsorbate + activated carbon/MOFs systems. The maximum adsorption driving force is found at the pore widths of 3 Å to 7 Å. The ∆go decreases with higher adsorbent-pore volume and depends on adsorbate molecule size. Employing the proposed driving force concepts, (i) the specific cooing, heating, and COP of the adsorption system, and (ii) the CO2/CH4 storage capacity in the adsorption cell can be projected and analyzed. The adsorption driving force relates to enthalpic and entropic interactions and is useful for the design of adsorbents and the selection of adsorbent-adsorbate pairs for gas storage, separation, and various energy-related applications. Ministry of Education (MOE) The authors acknowledge the financing support from the Ministry of Education (MOE), Singapore (grant reference no. RG 98/17).

Data for solubility of hydrogen in liquid aluminium from 17 studies have been reanalysed, based on the concept that solubility refers to maximum concentration that can be held in solution. Analysis...

Henry’s law constant data for the noble gases helium, neon, argon, krypton, xenon, and radon in the pure solvents water, methanol, ethanol, and propan-2-ol are predicted over a wide temperature range by molecular simulation. Furthermore, gas solubility measurements are carried out for neon, krypton, and xenon in propan-2-ol, yielding experimental Henry’s law constant values that are employed, together with data from the literature, to evaluate present simulation results. Suitable molecular force field models are identified for each binary system, and new models for helium and neon are presented. By examining the entire set of binary systems, a characteristic trend of the solubility behavior concerning the molecular size of the solutes and solvents is identified. The present work contributes consistent Henry’s law constant data for 24 binary solute–solvent pairs over the entire relevant temperature range and improves the database considerably.

A method is developed for predicting the sorption parameters of polymers (the infinite dilution solubility coefficient of gases S and the Henry law equilibrium constant kD of double sorption models) of most light gases in glassy polymers on the basis of a computer model of a polymer chain segment. From the molecular dynamic model of conformations of a short (about 200–600 atoms) segment of the polymer chain, the dependences of a number of geometric indices, such as the accessible surface area and the accessible surface area with a positive partial charge, on the probe radius (in fact, on the effective radius of penetrant or sorbate) are calculated. The linear approximation coefficients of these dependences are used as explanatory variables in multiple linear regression. Significant variables and their weights in regression are determined on the basis of experimental measurements from the Database of Physicochemical Properties of Polymers of the Laboratory of Membrane Gas Separation at the Institute of Petrochemical Synthesis, Russian Academy of Sciences. By using a more accurate algorithm for calculating the areas of macromolecules, the shortcomings of the first version of this method are eliminated. For S, the coefficient of regression determination (adjusted R2) on the test sample is equal to 0.8 (this corresponds to an average relative error of 77% in predicting S, which is considered good accuracy), and for kD, the coefficient of determination is 0.81 and the average relative error is 47%, which is also a good result considering large (up to decimal order) errors of the experimental measurements of S and kD.

The solubility and decomposition kinetics of ozone in pure water at different temperatures were studied. The Henry constant of ozone, kinetic order, and decomposition rate constant were determined. It was shown that to determine the concentration of dissolved ozone, it is sufficient to use the Henry law [O3] = $${{H}_{{{{{\text{O}}}_{{\text{3}}}}}}}$$ C(O3), where [O3] and C(O3) are the ozone concentrations in solution and gas phase (M), respectively; and the Henry constant is determined by the equality ln $${{H}_{{{{{\text{O}}}_{{\text{3}}}}}}}$$ = –(9.445 ± 1.00) + (2406 ± 300)/T (in the range 20–40°С). The dependence of the solubility on the kinetic characteristics of ozone decomposition and mass transfer, water purity, and reactor characteristics was discussed.

We propose a simple method to predict solubility in mixed solvents, combining experimental data for solubility in pure solvents with non-ideal contributions obtained from molecular simulation. By evoking a well-established thermodynamic model for mixed solvent, we provide rationale and justification for this hybrid approach. We test the accuracy of the method for solubility prediction in two highly non-ideal mixtures, CO 2 in ethanol + water, and CH 4 in MDEA + water. Non-ideal behaviour in each system is characterised using molecular simulation across the full range of compositions and for temperatures covering the range 273.15 K–373.15 K. Comparison against experimental Henry's law constants for CO 2 and CH 4 gives mean absolute errors of 6.9% and 27%, respectively. We investigate the origin of non-ideal Henry's law behaviour in each of the mixed solvents by interrogating radial distribution functions from molecular simulation, finding increased association of CO 2 and CH 4 with the organic solvents at elevated temperatures.

Gas-particle partitioning of water-soluble organic compounds plays a significant role in the formation and source apportionment of organic aerosols, but is poorly characterized. In this work, gas- and particle-phase concentrations of isoprene oxidation products (C5-alkene triols and 2-methylterols), levoglucosan, and sugar polyols were measured simultaneously at a suburban site of the western Yangtze River Delta in east China. All target polyols were primarily distributed into the particle phase (85.9–99.8 %), and their average particle-phase fractions were not strictly dependent on vapor pressures. Moreover, the measurement-based partitioning coefficients (Kp,OM) of isoprene oxidation products and levoglucosan were 102 to 104 times larger than their predicted Kp,OM based on the equilibrium absorptive partitioning model. These are likely attributed to the hygroscopic properties of polyol tracers and high aerosol liquid water (ALW) concentrations (~20 µg m−3) of the study location. Due to the large gaps (up to 107) between measurement-based effective Henry's law coefficients (KH,e) and predicted values in pure water (KH,w), the gas-particle partitioning of polyol tracers could not be depicted using Henry's law alone either. The regressions of log (KH,w/KH,e) versus molality of major water-soluble components in ALW indicated that sulfate ions (salting-in effect) and water-soluble organic carbon can promote the partitioning of polyol tracers into the aqueous phase. These results suggest a partitioning mechanism of enhanced aqueous-phase uptake for polyol tracers, which partly reveals the discrepancy between observation and modeling of secondary organic aerosols.

International audience; Henry's law constants (HLC) play a key role in the environmental fate of pesticides and their distribution between the different phases, i.e., between air, water and soil. For certain compounds such as fenpropidin and pyrimethanil, HLC values are poorly documented in the literature and in particular their temperature dependence. This work reports the experimental HLC values of two pesticides, namely fenpropidin and pyrimethanil, determined by means of a dynamic equilibrium system coupled to an off-line analysis performed by Gas Chromatography–Photoionisation Detection (GC–PID). The measurements were conducted over the range 278–293 K.In pure water, the experimental average values of HLC at 293 K were: HLC293K(fenpropidin) = (10.0 ± 3.1) × 104 M atm–1, HLC293K(pyrimethanil) = (8.2 ± 0.7) × 104 M atm–1. The obtained data were used to derive the following Arrhenius expressions where the quoted errors represent 2σ: ln HLC (fenpropidin) = (6060 ± 2420)/T – (9.1 ± 8.3); ln HLC (pyrimethanil) = (14570 ± 1800)/T – (38.4 ± 6.2). The environmental implications are then discussed in terms of lifetime or partitionning between the different atmospheric compartments.

The Henry's law constant defines the solubility of a gas in a liquid solution. In this study, a new method for measuring the Henry's law constant is described. This new colorimetric method is suited for gases which react with water to form acidic or basic solutions when they dissolve, and makes use of measuring the concentration of two forms of a colorimetric pH indicator. By measuring the concentration of the protonated and deprotonated forms of the indicator with UV-visible absorption spectroscopy, the concentration of the hydronium in solution was determined. After determining the hydronium concentration, the equilibrium expression for the dissolved gas reacting with water was solved to determine the concentration of the dissolved gas. The concentration of the dissolved gas and the measured partial pressure of the dissolved gas at equilibrium were then used to calculate the Henry's law constant for the gas. The efficacy of the method is demonstrated by measuring the Henry's law constant for carbon dioxide in water over a range of pressures (0.680 - 5.10 atm). The results obtained with this method are comparable to the value for the Henry's law constant that have been previously reported via more traditional methods, and yielded values for the Henry's law constant for carbon dioxide that ranged from 3.45 × 10-2 to 3.99 × 10-2 M atm-1.

Greater public, and research, focus on oceanic and atmospheric oxygen budgets is needed. Oceans are “losing their breath”; there has been a 1-2% loss, 77-154 gigatons (GT) of total oceanic oxygen (...

The fate of a pollutant in the environment depends on its interaction with the surroundings. Henry's law constant (HLC) is one of the important properties useful for assessment of environmental risk and estimation of mass transfer of the pollutant between water and air. Estimation of HLC is relatively a difficult task for many of the organic pollutants due to their very low aqueous solubility. People have attempted the measurement of HLC for persistent organic pollutants, such as polychlorinated biphenyls (PCBs), but due to the difficulty in estimation, there is a variation of approximately 2-3 orders of magnitude in reported values of HLC for PCBs in the literature. A study was performed for estimation of HLC for PCBs using the static method with a modification that eliminates any disturbance in equilibrium due to sampling and also avoids removal or addition of material in or out of the system unlike the conventional methods. The results were consistent with the literature values. The experimental values of HLC ranged from 0.004 to 0.08 for different congeners. All of the experimental values were in agreement with the literature values. The experimental data was further used for deriving a correlation equation for theoretical estimation of the HLC from aqueous solubility and chlorination number. The equation gave a very good estimation of HLC values for all the PCBs congeners except single- and double-chlorinated congeners. The theoretically predicted values were also found to be in close agreement with the reported HLC values.

Grand Canonical Monte Carlo simulation of methanol adsorption on a graphite model with two hydroxyl groups grafted on the surface has been carried out to investigate the effects of temperature in the range of 278–360 K. The spacing between the OH groups was chosen so that two hydrogen bonds could be formed with the first methanol molecule. In the Henry law region, the isosteric heat at zero loading is greater than the condensation heat. When the loading is increased, the isosteric heat at low temperatures decreases slightly and exhibits a shoulder, which is associated with the formation of a cluster of methanol molecules around one OH group. On further increase in loading, the adsorbate–adsorbate interactions decrease because methanol begins to adsorb on the other OH group, resulting in a sharp decrease in the isosteric heat to a minimum, at which point both OH groups are covered with methanol molecules. At higher temperatures the isosteric heat at zero loading decreases but remains higher than the condensation heat. The shoulder heat is progressively diminished with temperature because methanol molecules are distributed over the two OH groups, due to the entropic effects. Interestingly, the minimum heat still occurs when the functional groups are covered and is even more pronounced at high temperatures.

Crust-derived helium is generated from the radioactive decay of uranium, thorium and other radioactive elements in geological bodies. Compared with conventional natural gas, helium is a typical weak source gas as a result of extremely slow generation rate and absence of helium-generating peak. It is associated with methane or carbon dioxide reservoirs frequently and related to groundwater closely. Helium can meet the industry standard with 0.1% in volume fraction. In order to study the accumulation mechanism of helium, the previous research on Henry's coefficient and solubility of helium, nitrogen and methane are summarized and the key roles of Henry's Law in the helium migration, accumulation and preservation are discussed by simulating calculation taking Weihe Basin as an example. According to the Law, the gas solubility in dilute solution is controlled by the gas partial pressure and the Henry's coefficient. Compared with the carrier gases, the Henry's constant of helium is high, with striking difference at low and high temperature. In addition, the helium partial pressure is greatly different in helium source rocks and gas reservoirs, resulting in the great differences of helium solubility in the two places. The accumulation progresses are as follows. Firstly, helium can dissolve into water and migrate out of helium source rocks due to the high helium solubility, which is caused by high helium partial pressure and high temperature in source rock. Secondly, when dissolved helium is transported to the shallow gas reservoir, it is prone to be out of solution and into reservoir due to the extremely low partial pressure and low temperature. Meanwhile part of carrier gases dissolves into water, as if helium is “replaced” out. Furthermore, the low concentration funnel of dissolved helium is formed near the gas reservoir, then other dissolved helium continues to migrate towards the gas reservoir, which greatly improves the helium accumulation coefficient. Finally, after entering the gas reservoir, helium is difficult to dissolve into the water in cap layers due to its low partial pressure, resulting in the preservation of helium in reservoir. The results show that the helium enrichment mechanism in the aspects of migration, accumulation and preservation, providing theoretical basis for helium resource exploration. Keywords: Helium, Accumulation, Henry's law, Weihe Basin

The Henry’s law constants of n-hexanal are needed to predict its rate of mass transfer between gas and aqueous phases. However, information on these constants is limited because the mass transfer of n-hexanal involves a reversible hydration reaction in water; therefore, Henry’s law constants are difficult to obtain experimentally and cannot be deduced only from the gas-to-water equilibrium. Here, we conducted stimulus–response experiments using a rectangular input pulse and a double-mixing gas–liquid contactor to simultaneously determine Henry’s law constants and hydration equilibrium constants for n-hexanal in deionized water, aqueous sodium chloride, or aqueous sodium sulfate in the temperature range of 5.3–22.5 °C. The change in the concentration of a mixture of n-hexanal in nitrogen gas after passing through the contactor was examined, and simulation-based optimization was conducted to optimize parameters that included Henry’s law constants and hydration rate constants. In the simulation, convolution using the rectangular input pulse was used to determine the input signal, and perfect gas-phase mixing and two-film layer mass transfer were assumed. This approach, which we called the rectangular pulse method, was validated by performing similar investigations for toluene, ethyl acetate, and ethyl trifluoroacetate. As a result, Henry’s law constants and rate constants for the reversible hydration reactions of n-hexanal and their temperature dependence were obtained, and the calculated effective Henry’s law constant agreed with some, but not all, of the values reported in the literature. A potential reason for the disagreement was discussed from the viewpoint of long time-constants used for the hydration equilibrium. In addition, a salting effect by the aqueous salt solutions was found to affect the Henry’s law constants, but not the hydration equilibrium constants. The overall liquid‐side mass‐transfer coefficient was found to be correlated with the diffusion coefficient, based on the Higbie penetration theory.

Dissolved gases produce a gas pressure. This gas pressure is the appropriate physical quantity for judging the possibility of bubble formation and hence it is central for understanding exchange of climate-relevant gases between (limnic) water and the atmosphere. The contribution of ebullition has widely been neglected in numerical simulations. We present measurements from six lacustrine waterbodies in Central Germany: including a natural lake, a drinking water reservoir, a mine pit lake, a sand excavation lake, a flooded quarry, and a small flooded lignite opencast, which has been heavily polluted. Seasonal changes of oxygen and temperature are complemented by numerical simulations of nitrogen and calculations of vapor pressure to quantify the contributions and their dynamics in lacustrine waters. In addition, accumulation of gases in monimolimnetic waters is demonstrated. We sum the partial pressures of the gases to yield a quantitative value for total gas pressure to reason which processes can force ebullition at which locations. In conclusion, only a small number of gases contribute decisively to gas pressure and hence can be crucial for bubble formation.

RATIONALE 4-Alkyl branched-chain fatty acids and 3-methylindole are characteristic flavor compounds associated with sheep meat. Determining their partitioning behavior between the gas and condensed phase and ultimately developing a correlation between the compound's headspace concentration and sensory descriptive grouping are important for high-throughput characterization and grading classification. METHODS The headspace concentrations of 3-methylindole, 4-methyloctanoic acid, 4-ethyl-octanoic acid, and 4-methylnonanoic acid above corn-oil-based standard solutions and lamb fat samples were measured using selected ion flow tube-mass spectrometry (SIFT-MS). The standard solutions were equilibrated at 80, 100, 110 and 125°C while the fat samples were equilibrated at 125°C. Statistical evaluation, linear and polynomial regression analyses were performed to establish the compound-specific and temperature-dependent Henry's Law constants, enthalpy (ΔH) and entropy (ΔS) of phase changes. RESULTS The Henry's Law constants (kHcp ) were calculated from the regression analysis with a high degree of confidence (p 0.99). The kHcp increased with increase in equilibrium temperature. The empirical calculation of ΔH and ΔS at different temperatures confirmed the temperature-dependence of the Henry's Law constants. The headspace concentrations of the lamb-flavor compounds were determined above actual lamb fat samples and the corresponding condensed-phase concentrations were successfully derived. CONCLUSIONS The temperature-dependent Henry's Law constants, ΔH, and ΔS of phase changes for 3-methylindole, 4-methyloctanoic acid, 4-ethyloctanoic acid, and 4-methylnonanoic acid in an air-oil matrix were empirically derived. The effectiveness of SIFT-MS for the direct, real-time, and rapid determination of key flavor compounds in lamb fat samples was established.

Accurate Henry's law constants (H) are unavailable for the majority of organic pollutants, especially those having a low volatility. A novel kinetics-based experimental method is introduced to determine H for a wide range of low-H compounds. The method consists of measuring independently the water-to-air transfer coefficient (KL) and the associated air-phase transfer coefficient (kG) of a low-H chemical (solute) in water when KL ≅ kGH prevails according to the two-film theory. The kG for a solute is obtained via a developed gas-dynamic equation that relates kG to the solute molecular weight and the solute-vapor escaping efficiency (β) through a boundary air layer. The value of β is only a function of the in situ air turbulence level, independent of the chemical species. Thus, the required β for solutes can be estimated from the evaporative rates of pure volatile liquids under the same ambient setting. By relating the estimated kG with the measured KL of a low-H solute, the solute H is established. The H values of 45 low-H chemicals, including many complex pesticides, in the range of ∼10−7 to ∼10−3 have thus been determined. The accountability of the method is underscored by the consistency of the measured and credible literature H values for a number of the low-H compounds studied.

To obtain an understanding of the ethanol loss during cooking of liquid foods containing alcoholic beverages, ethanol concentration was measured as a function of time and remaining volume in meat stocks prepared with wine and beer. A mathematical model describing the decline in volatile compounds during heating of simple liquid foods was derived. The experimental results and the model show that concentration of ethanol at any given time is determined by the initial concentration and a power law function of the remaining volume fraction. The power law function is found to be independent of factors like pot dimensions and temperature. When using a lid to cover the pot during cooking, the model was still valid but the ethanol concentrations decreased more steeply, corresponding to a higher exponent. The results provide a theoretical and empirical guideline for predicting the ethanol concentration in cooked liquid foods.

The measurement of dissolved hydrogen in the primary systems of pressurized water reactors (PWRs) is difficult; hence, hydrogen concentrations are predicted by model equations. An accurate value for the Henry’s law constant for hydrogen is needed if the use of these equations is to be meaningful. The purpose of this study is to develop an empirical correlation for determining the Henry’s law constant for application to nuclear reactors. The effects of temperature and pressure on the Henry’s law constant are investigated using simulated PWR primary-water conditions. The Henry’s law constant was calculated by an in-situ measurement of the partial pressure of hydrogen using a hydrogen sensor based on a Pd–Ag alloy tube. At 20 MPa, the Henry’s law constant decreased by ∼40% as the temperature increased from 290 to 330 °C. The Henry’s law constant increased by an average of 9% as the pressure increased from 13.8 to 20 MPa at each temperature. Thus, it depends more strongly on the temperature than on the pressure. Based on the experimental data, an empirical correlation for predicting the Henry’s law constant was developed using a linear regression method, which was validated by comparing with results in the literature. The deviation between the Henry’s law constant obtained using our model and that reported in the literature was in the range of 0.5%–10%. The hydrogen fugacity estimated using our model was within 10% of that found in the literature. Thus, the proposed empirical model appears to be more accurate than previously published models.

Gas–particle partitioning governs the distribution, removal, and transport of organic compounds in the atmosphere and the formation of secondary organic aerosol (SOA). The large variety of atmospheric species and their wide range of properties make predicting this partitioning equilibrium challenging. Here we expand on earlier work and predict gas–organic and gas–aqueous phase partitioning coefficients for 3414 atmospherically relevant molecules using COSMOtherm, SPARC Performs Automated Reasoning in Chemistry (SPARC), and poly-parameter linear free-energy relationships. The Master Chemical Mechanism generated the structures by oxidizing primary emitted volatile organic compounds. Predictions for gas–organic phase partitioning coefficients (KWIOM/G) by different methods are on average within 1 order of magnitude of each other, irrespective of the numbers of functional groups, except for predictions by COSMOtherm and SPARC for compounds with more than three functional groups, which have a slightly higher discrepancy. Discrepancies between predictions of gas–aqueous partitioning (KW/G) are much larger and increase with the number of functional groups in the molecule. In particular, COSMOtherm often predicts much lower KW/G for highly functionalized compounds than the other methods. While the quantum-chemistry-based COSMOtherm accounts for the influence of intra-molecular interactions on conformation, highly functionalized molecules likely fall outside of the applicability domain of the other techniques, which at least in part rely on empirical data for calibration. Further analysis suggests that atmospheric phase distribution calculations are sensitive to the partitioning coefficient estimation method, in particular to the estimated value of KW/G. The large uncertainty in KW/G predictions for highly functionalized organic compounds needs to be resolved to improve the quantitative treatment of SOA formation.

Gas-to-water equilibrium coefficients, KeqS (in M atm−1), of difluoromethane (CH2F2), a hydrofluorocarbon refrigerant (HFC-32), in aqueous salt solutions relevant to seawater were determined over a temperature (T) range from 276 to 313 K and a salinity (S) range up to 51 ‰ by means of an inert-gas stripping method. From the van't Hoff equation, the KeqS value in water, which corresponds to the Henry's law constant (KH), at 298 K was determined to be 0.065 M atm−1. The salinity dependence of KeqS (the salting-out effect), ln(KH∕KeqS), did not obey the Sechenov equation but was proportional to S0. 5. Overall, the KeqS(T) value was expressed by ln(KeqS(T)) = −49.71 + (77.70 − 0.134 × S0. 5) × (100∕T) + 19.14 × ln(T∕100). By using this equation in a lower-tropospheric semi-hemisphere (30–90 °S) of the Advanced Global Atmospheric Gases Experiment (AGAGE) 12-box model, we estimated that 1 to 4 % of the atmospheric burden of CH2F2 resided in the ocean mixed layer and that this percentage was at least 4 % in the winter; dissolution of CH2F2 in the ocean may partially influence estimates of CH2F2 emissions from long-term observational data of atmospheric CH2F2 concentrations.

Different types of physical solvents have been utilized for CO2 removal from natural gas in the sweetening process. In this work, quantitative structure-property relationship (QSPR) method is suggested to build powerful models to predict Henry’s law constant (HLC) for CO2 in physical solvents. Modeling the HLC for CO2 as a function of molecular descriptors was achieved by multiple linear regression and descriptor selection was by genetic algorithm. The main proposed model has two simple descriptors, including the number of hydroxyl groups and molecular weight of solvents at fixed temperature. Also, the effect of temperature was studied, and this operational variable was added to the mentioned simple descriptors. In this case, the data set is comprised of 77 HLC for CO2 in solvents and at different temperatures. Several internal and external validation methods demonstrated the excellent ability for prediction, and the average relative deviation of main model was 6.48.

Associate surplus substances presence in natural gases like carbon dioxide (CO 2 ) causes prominent problems in transporting and storage stages. Unique features of ionic liquids such as low vapor pressure, excellent thermal and chemical stability, high power of dissolution, etc., have made them as green solvents and organic solvents substitution in the separation processes, especially the separation of CO 2 . Although many experimental works have been done to determine the ability of ionic liquids in separation of CO 2 , expensive and time-consuming laboratory methods have led to a strong interest in the modeling methods. In this work, quantitative structure–property relationship (QSPR) models for predicting the Henry’s law constant ( H L C ) for CO 2 dissolution in 32 ionic liquids have been developed. Chosen descriptors by genetic algorithm were used to develop two models by MLR and LS-SVM methods. The three-parameter model has been considered as the main model and a detailed physical interpretation has been mentioned for all parameters. Comparison of the predicted values of H L C with the experimental data, internal validation results and statistical parameters show that the proposed QSPR model by MLR and LS-SVM methods are reliable, predictive and stable; however the non-linear model is more powerful than the linear one.

This article presents the design and construction of a new isochoric saturation apparatus for the determination of gas solubility in liquids based on the gas drop pressure method. The major improvement of this design is the separation between the solubility and the gas cells. With this separation, the change of pressure and temperature inside the system is minimum when the gas gets in contact with the liquid and it allows degassing the liquid in an easy way. The performance of the equipment was evaluated measuring the solubility of argon and nitrogen in pure water at 283.15, 288.15, 293.15, and 298.15 K. The gas solubility was calculated according to the Henry's law. The results obtained and the comparison with literature values show that the equipment provides an accurate and precise method for determination of gas solubility in water. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3105–3109, 2017

Nitrogen is usually used to increase the total pressure of the fluid in aircraft fire suppression bottle. The amount of nitrogen required in the bottle is a significant factor to assure complete and effective discharge into the protected area and it depends on the solubility of the nitrogen in the fire extinguishing agent. In this article, the Peng-Robinson equation of state (PR EOS) including both the classical van der Waals mixing rule and the Wong-Sandler mixing rule is utilized to correlate the Gas-Liquid Equilibrium (GLE) data from available open published literature and to analyze the solubility of nitrogen in halon alternatives such as HFC227ea (C3HF7), CF3I, FC218 (C3F8), and HFC125 (C2HF5) with Halon1301 (CF3Br) as a reference. A new method is proposed to compute the adjustable interaction parameters in the van der Waals mixing rule and in the Wong-Sandler mixing rule based on the measurements of nitrogen required to pressurize the fire suppression bottle to a specified equilibrium pressure at room temperature. Results show that the PR EOS reproduces the GLE data very well with both van der Waals mixing rule and the Wong-Sandler mixing rule and it is then utilized to predict the temperature dependence of the Henry’s law constants of nitrogen dissolved in the fire extinguishing agents. The PR EOS with van der Waals mixing rule is much more appropriate for determining the Henry’s constants than that with the Wong-Sandler mixing rule and the results calculated by the current model are used to establish a new correlation for the Henry’s law constants. This correlation will be very helpful for fire extinguishing bottle designers to acquire the pressure-temperature relationships for the mixture of nitrogen and agents.

High hydrophobicity and volatility of chemicals often lead to substantial experimental challenges but were here utilized in headspace passive dosing (HS-PD) to establish and maintain exposure: the pure chemical served as a passive dosing donor for controlling exposure at saturation, whereas triglyceride oil containing the chemical was used to control lower exposure levels. These donor solutions were added to glass inserts placed in the closed test systems. Mass balance calculations confirmed a dominant donor capacity for all chemicals except isooctane. This HS-PD method was applied to algal growth inhibition and springtail lethality tests with terpenes, alkanes, and cyclic siloxanes. Headspace concentrations above the lipid donors were measured for three chemicals to determine their chemical activity, using saturated vapor as the analytical standard and thermodynamic reference. Toxicity was related to chemical activity and calculated concentrations in membranes at equilibrium with the lipid donor. For both tests and all chemicals, toxic effects were observed within or above the reported range for baseline toxicity, meaning that no excess toxicity was observed. The toxicity of siloxanes was markedly higher to the terrestrial springtail than the aquatic algae, which is consistent with a more efficient mass transfer of these volatile hydrophobic chemicals in air compared to water.

Henry’s law constant data for nitrogen, oxygen, and argon in the ternary liquid mixture water + methanol + ethanol as well as its pure and binary solvent subsystems are reported. The composition and temperature dependence of the Henry’s law constant of the air components in these solutions is investigated by Monte Carlo simulation. The underlying molecular force field models are based on the modified Lorentz–Berthelot combining rules that contain one binary interaction parameter, which is mainly taken from preceding work. Predictions from the molecular models for the pure and binary solutions are convincingly compared to experimental literature data, where available. This finding gives confidence that the Henry’s law constant for the ternary solution is predicted appropriately. On the basis of an extensive molecular simulation data set, correlations are established for the Henry’s law constant between 274.15 and 473.15 K.

In this paper, we report the CO2, CH4 and N2 sorption isotherms of four dry South African bituminous coals at pressures up to 16 MPa at 55 °C. The sorption capacities of the samples with respect to the adsorbate gases decreased in the order: CO2 > CH4 ≈ N2 by weight, and CO2 > CH4 > N2 by volume. A new model, based on a hybrid Dubinin-Radushkevich and Henry law approach (DR-HH) provided substantially better fits to the sorption isotherm data than the previously used modified DR (M-DR) model. Obtained uncertainty metrics show that the DR-HH model generally returned lower error sum of squares (ESS) and root mean square (RMS) residuals, and higher quality of fit (QOF) compared to the M-DR model. The net heat of sorption, βEs, of the samples for the three adsorbate gases were generally low (8.5–12.8 kJ/mol), but comparable to previous determinations of other coals, indicating that physisorption was the dominating sorption mechanism. The sorption capacities of the samples were found to be rank-dependent as they decreased with increasing vitrinite reflectance and elemental carbon content. The micropore properties of the samples as measured by both CO2 low-pressure gas adsorption (LPGA) and small angle X-ray scattering (SAXS), impacted the sorption properties of the sample more than both the mesopore and macropore properties determined from N2 LPGA, SAXS, and mercury intrusion porosimetry. The sorption capacities of the samples were found to increase with increasing lithotypes abundance, suggesting that lithotype bandings enhances either the fluid transport processes or the micropore properties of the coal matrix. In addition, it has been demonstrated that critical properties of the adsorbate gases influenced their sorption properties.

Agradecimentos: The authors thank the financial support from CAPES Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Abstract: Fischer-Tropsch synthesis (FTS) is a catalytic process to convert synthesis gas ( and CO) into fuels, as diesel and gasoline. It is an alternative to produce renewable fuels from raw materials such as biomass. Although a real catalytic FTS is not in equilibrium, the thermodynamic analysis of FTS provides a comprehension of the chemical and phase equilibrium for products and reactants in this process. Therefore, this paper aimed to study the thermodynamic equilibrium of FTS using Gibbs energy minimization, allowing to calculate the equilibrium for an isotherm system. Cubic equations of state (CEOS) and Henry's law were employed to represent the non-ideality of the system. The method is formulated as an optimization problem, in which the Gibbs energy minimization is the objective function, and the roots from CEOS are selected by incorporating derivative constraints for each phase (vapor and liquid). Besides, the constraints regarded in this problem are the following: non-negative number of moles, mole balances, and inhibition of methane formation. We evaluated the equilibrium composition for different temperatures, pressures and synthesis gas inlet rate. The results show that CEOS embedded in an optimization problem, through nonlinear programming, is capable of predicting the phase and chemical equilibrium accurately, robustly, and with low computational effort, for a multiphase and multicomponent system. Furthermore, chemical equilibrium for FTS tends to yield light hydrocarbons as much as the rates of in the inlet increasing COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Fechado

Dynamic headspace sampling is an important technique for the analysis of consumer products, the study of biological samples and environmental water analyses. This paper shows the influence of experimental conditions, such as the sampling time, sampling flow rate, headspace volume, liquid volume and Henry coefficient on the measured average concentration values. A corresponding closed expression as function of these variables is introduced in order to quantify the deviation of the initial headspace concentration. The proposed bi-exponential function embeds different current existing models for recovery calculation in dynamic sampling analyses in one single expression. A fully automated and user-friendly Excel® file to investigate or to model the dynamic headspace sampling results is added to everyone's easy use.

Formation of aerosol from biogenic hydrocarbons relies heavily on anthropogenic emissions since they control the availability of species such as sulfate and nitrate, and through them, aerosol acidity (pH). To elucidate the role that acidity and emissions play in regulating Secondary Organic Aerosol (SOA), we utilize the 2013 Southern Oxidant and Aerosol Study (SOAS) dataset to enhance the extensive mechanism of isoprene epoxydiol (IEPOX)-mediated SOA formation implemented in the Community Multiscale Air Quality (CMAQ) model (Pye et al., 2013), which was then used to investigate the impact of potential future emission controls on IEPOX OA. We found that the Henry’s law coefficient for IEPOX was the most impactful parameter that controls aqueous isoprene OA products, and a value of 1.9 × 107 M atm−1 provides the best agreement with measurements. Non-volatile cations (NVCs) were found in higher-than-expected quantities in CMAQ and exerted a significant influence on IEPOX OA by reducing its production by as much as 30% when present. Consistent with previous literature, a strong correlation of isoprene OA with sulfate, and little correlation with acidity or liquid water content, was found. Future reductions in SO2 emissions are found to not affect this correlation and generally act to increase the sensitivity of IEPOX OA to sulfate, even in extreme cases.

For obtaining relevant information about the development of hydrogen storage materials from metal organic frameworks (MOFs), MIL-101(Cr) was selected and synthesized for analyzing the adsorption equilibrium and characteristics of charge and discharge. The specific surface area, pore size distribution (PSD) of the sample were determined by 77.15 K nitrogen adsorption data. Isotherms of hydrogen adsorption on the sample were volumetrically measured at 77.15 K and 87.15 K, 0–100 KPa and 0–6 MPa. Henry law constants and Toth equation were respectively used to determine the isosteric heat of adsorption. A 3.2 L conformable vessel, which can meet the fuel consumption of 7.5 kW PEMFC under typical working condition for about 10 min, was designed and undergone charge and discharge tests at ambient temperature and 77.15 K under the flow rate 10–50 L·min−1. Results show that the limit isosteric heat of adsorption on the sample is 7.368 kJ·mol−1, while the mean Isosteric heat determined by the Toth potential function is 2.925 kJ·mol−1. Results also reveal that, at 77.15 K, the ratio of hydrogen released is 80%, 79.4%, 77.2% and 76.1% at the flow rate of 20–50 L·min−1; while at 301.15 K, the ratio is 85.1%, 85.0% and 82.3% with corresponding flow rate 10–30 L·min−1. It suggests that the storage amount and the characteristics of charge/discharge on hydrogen-MIL-101(Cr) system at cryogenic temperature can meet the fuel requirements of the fuel cell.

In this work, we predicted the hydrate formation conditions for the pure and mixed gas systems of CH 4 , N 2 , O 2 and CO 2 in the presence of cyclopentane or cyclohexane. Chen-Guo model coupled with the predictive Soave-Redlich-Kwong (PSRK) group contribution method was used to calculate the three-phase equilibrium, and the UNIFAC model was employed to calculate the activity coefficient of the liquid phase. The pressure-corrected Henry’s law was employed to calculate the mole fraction of gas components existing in the aqueous phase except water. The prediction results and the percent of Absolute Average Deviation for the calculated hydrate formation pressures and temperatures were presented. It was found that the results predicted in this work agree well with those reported in the literature. Cyclopentane and cyclohexane in aqueous phase was assumed to evaporate into the gas phase and may change the gas components and the corresponding mole fractions in the gas phase. However, the results showed that the concentration variation of cyclopentane or cyclohexane has slight impact on the hydrate formation thermodynamics.

A generalized expression for estimating the solubility or air gases (oxygen, nitrogen and argon) in saline solutions at atmospheric pressure is presented. The generalization is done for the Henry's constant (to consider the effect of temperature) and for the Setschenow parameter (to consider the effect of salt content in the solution), in terms of the acentric factor, the temperature, and the salinity expressed as the total content of salt. Accurate correlation and prediction of gas solubility is important in various scientific and technological fields and for the design of separation equipment in the chemical and mining-related industries. As a measure of the accuracy of the generalized model, the average deviation, the absolute average deviation and the maximum absolute deviation between correlated and experimental data are evaluated. The proposed model give absolute deviations lower than 1% with some few exceptions, and maximum deviations are always below 4%.

Thermodynamic phase equilibrium calculations for systems containing water are inseparable parts of the compositional hydrocarbon reservoir simulation. In this regard, stability analysis of the phases for distinguishing the existing ones at specific pressures and temperatures is a principal part of such calculations. This study is aimed to develop a new stability algorithm with application to three phase flash calculations in the presence of brine. The developed scheme is capable of doing the phase behavior calculations in a more robust way compared to the other available algorithms. Henry's law is utilized to predict the aqueous phase properties, and a new initial guess is provided for three phase flash calculations that assures the convergence of the scheme. It is shown that the proposed procedure is able to handle the systems with high CO 2 content while the available schemes in the literature fail.

Worldwide, chemical spills degrade drinking water quality and threaten human health through ingestion and inhalation. Spills are often mixtures of chemicals; thus, understanding the interaction of chemical and biological properties of the major and minor components is critical to assessing human exposure. The crude (4-methylcyclohexyl)methanol (MCHM) spill provides an opportunity to assess such subtleties. This research determined the relative amounts, volatilization, and biological odor properties of minor components cis- and trans-methyl-4-methylcyclohexanecarboxylate (MMCHC) isomers and major components cis- and trans-4-MCHM, then compared properties and human exposure differences among them. (1)H nuclear magnetic resonance and chromatography revealed that the minor MMCHC isomers were about 1% of the major MCHM isomers. At typical showering temperature of 40 °C, Henry's law constants were 1.50 × 10(-2) and 2.23 × 10(-2) for cis- and trans-MMCHC, respectively, which is 20-50 fold higher than for 4-MCHM isomers. The odor thresholds were 1.83 and 0.02 ppb-v air for cis- and trans-MMCHC, which were both described as predominantly sweet. These data are compared to the higher 120 ppb-v air and 0.06 ppb-v odor thresholds for cis- and trans-4-MCHM, for which the trans-isomer had a dominant licorice descriptor. Application of a shower model demonstrated that while MMCHC isomers are only about 1% of the MCHM isomers, during showering, the MMCHC isomers are 13.8% by volume (16.3% by mass) because of their higher volatility. Trans-4-MCHM contributed about 82% of the odor because of higher volatility and lower odor threshold, trans-MMCHC, which represents 0.3% of the mass, contributed 18% of the odor. This study, with its unique human sensory component to assess exposure, reaffirmed that hazard assessment must not be based solely on relative concentration, but also consider the chemical fate, transport, and biological properties to determine the actual levels of exposure across different media.