Solubility Of Oxygen In Water Research Articles

Enhancement of citric acid production by Aspergillus niger using n-dodecane as an oxygen-vector

Due to the significant oxygen requirement during citric acid production and the relatively low solubility of oxygen in water, aeration is critical. The potential use of n-dodecane as an oxygen-vector for improvement of citric acid production by Aspergillus niger was studied. The volumetric fraction of oxygen-vector has a great influence on the volumetric oxygen transfer coefficient k La. With the addition of an oxygen-vector to the fermentation medium with a final concentration of 5%, the k La value reached a maximum value (130 h −1), which is twice that of the control experiment. The addition of 5% (v/v) n-dodecane enhanced citric acid accumulation, reduced residual sugar concentration and stimulated mycelial growth. Adding n-dodecane had no adverse effects on the cells of A. niger. The results of enzyme assays indicated that no significant differences were observed between the activity of citrate synthase of two kinds of mycelial cell-free extracts.

Modeling Oxygen Solubility in Water and Electrolyte Solutions

A model is presented for estimating oxygen solubility in water and solutions of inorganic electrolytes (I) as a function of oxygen pressure PO2 (atm), temperature T (K), and I. It is based on a thermodynamic analysis for water, where the molal concentration caq of oxygen follows an equation of the form caq = PO2k and k is a T-dependent function (equilibrium constant) related to the chemical potential, entropy, and partial molar heat capacity of the gaseous oxygen (O2)g and dissolved oxygen (O2)aq species. In the presence of I, the oxygen solubility becomes (caq)I = φcaq, where φ is a modifying factor < 1 that is dependent on I and its molal concentration CI. The decreasing molar heat capacity of (O2)aq with rising T, which affects k, is discussed. The decrease in φ with increasing CI is related in a general way to the decrease in partial molar volume of the water.

Hydrophobic effects: A computer simulation study of the temperature influence in dilute O2 aqueous solutions

We present a computer simulation study of the temperature dependence of the structural and dynamical properties of dilute O2 aqueous solutions. A clathrate-like solvation shell, in line with other apolar gas solutions, emerged from the present simulations. The average number of water molecules in the first hydration shell decreases with temperature, and, in the investigated temperature range (291–348 K), a net transfer of one water molecule from the hydration shell to the bulk has been detected. We have found oscillations of both water density and electrostatic charges in the neighborhood of the apolar solute, which is surrounded by shells of water at different density, and with water molecules oriented in such a way as to form shells with alternating net electrostatic charges. In the O2, first hydration shell water–water interactions are stronger and water diffusional and rotational dynamics slower than in the bulk. A hydrogen bond’s mean lifetime is affected by the apolar solute as well, being shorter in the first hydration shell. Differences between shell and bulk water properties are smoothed by increasing temperature. Suggestions for the molecular mechanism relevant to the more general problems of the hydrophobic effects are deduced from the simulations. A possible microscopic explanation for the lowering of solubility of oxygen in water with temperature is given.

Temperature and pressure dependent solubility of oxygen in water: a thermodynamic analysis

A thermodynamic analysis of the temperature dependent equilibrium between oxygen solubility (activity) in pure water and oxygen partial pressure P O 2 was undertaken. Experimental oxygen solubility sources were used to determine a set of self consistent values for the chemical potential, entropy and partial molar heat capacity of dissolved oxygen. These were combined with established thermodynamic data for gaseous oxygen to develop a single thermodynamic equation describing the relationship between gaseous oxygen fugacity, dissolved oxygen activity, temperature and the equilibrium constant k. This equation was consistent with k values calculated from published experimental solubility data for temperatures from 273 to 616 K and pressures to 60 atm, encompassing the conditions encountered during oxygen leaching operations. Within these ranges, it was shown that the gas fugacity and dissolved oxygen activity coefficients were sufficiently close to unity that the k-equation may be used to relate the molal concentration c aq of dissolved O 2 for any combination of temperature T (K) and P O 2 (atm), c aq =P O 2 0.046T 2+203.357T ln(T/298)−(299.378+0.092T)(T−298)−20.591×10 3 (8.3144)T The significance of the difference in heat capacity between gaseous and dissolved oxygen was discussed, leading to suggestions for incorporating the effects of dissolved mineral solutes into the oxygen solubility equation.

The effect of moisture condensation on the spontaneous combustibility of coal

The reaction-diffusion approach developed in previous work is extended to consider the effects of moisture evaporation and condensation on the rate of oxidation of coal. For a single isothermal particle, pseudo-steady-state balances on moisture and oxygen permit calculation of the effect of different levels of coal-bound moisture on the rate of oxidation. These species balances are combined with an energy balance to determine the particle temperature history during evaporation and condensation. It is shown that partial wetting of coal or condensation of moisture exerts two competing influences on the overall rate of oxidation. On the one hand, a portion of the coal fills up with liquid moisture; in this region, the rate of oxidation becomes negligible, since the oxygen has to dissolve in the moisture before it can gain access to an active site on the coal surface and the solubility of oxygen in water is low. On the other hand, condensation also leads to the release of the latent heat of vaporization. This heat effect raises the temperature of the particle and increases the rate of oxidation in the dry region of the coal. The relative magnitude of the rates of these competing influences determines whether the potential for spontaneous combustion is abated or enhanced. Based on the insight provided by the model, a simple criterion is derived to determine conditions under which condensation of moisture on coal can lead to spontaneous combustion. Field observations have consistently indicated that moisture condensation can enhance the potential for spontaneous combustion. This model is however thought to be the first mathematical description which links the coal-moisture interaction parameters (which can be determined independently) to the potential for spontaneous combustion.

Oxygen transfer limitation in a respirometer

The oxygen uptake process in a respirometer was analyzed by a mathematical model consisting of oxygen transfer accompanied with oxygen consumption reaction. The criterion to avoid an oxygen‐transfer limitation was derived on the basis of the ratio of the maximum biochemical reaction rate to the maximum possible oxygen‐transfer rate. The maximum biochemical reaction is described by the first‐order rate equation, whereas the maximum possible oxygen‐transfer rate is calculated by multiplying the oxygen‐transfer coefficient with the solubility of oxygen in water. An oxygen‐transfer coefficient in a respirometric reactor was estimated as 1.8 h−1, by using the model analysis of an oxygen uptake data from the same reactor. A simplified criterion for a respirometer without oxygen‐transfer limitation is then obtained as XS ≪ 16.51/K1 where X and S represent concentration of biomass and substrate, respectively, and K1 is the first‐order rate constant, (L/mg VSS)/h.

A method for simultaneous determination of solubility and transfer coefficient of oxygen in aqueous media using off‐gas mass spectrometry

A static method was developed that simultaneously determined the solubility of oxygen and the oxygen-transfer coefficient in a stirred bioreactor. It was based on the static method developed by van Sonsbeek et al. to determine the ka in a liquid-impelled loop reactor. Only physical properties of the liquid were used to determine both parameters using a mass spectrometer. Data about the solubility of oxygen in water are available from the literature. Therefore, the solubility of oxygen in water was used to compare our data with published data. Furthermore, the solubility of oxygen in trypticase soy broth was compared to literature data. No significant deviations between our data and literature data could be observed. Our static method and the commonly applied dynamic method to determine the oxygen-transfer coefficient yielded similar results. The effect of temperature on the oxygen-transfer coefficient could be expressed as the activation energy needed for the transition of oxygen from the gas to the water phase. This was verified using the Arrhenius equation.

Oxygen Diffusion through Soil Covers on Sulphidic Mine Tailings

Engineered soil covers are being evaluated under Canada's Mine Environment Neutral Drainage (MEND) program for their effectiveness in preventing and controlling acid generation in sulphidic mill tailings. A critical parameter for predicting the performance of these covers is the diffusion coefficient of gaseous oxygen in the cover materials. Laboratory experiments conducted to determine the effective diffusion coefficient of a candidate cover material, a glacial till from an active mine site, are described. The diffusion coefficient is determined by fitting a semianalytic solution of the one‐dimensional, transient diffusion equation to experimental gaseous oxygen concentration versus time graphs. Effective diffusion coefficients determined at high water saturations (85%–95%) were of the order of 8×10-8m2/s. The diffusion coefficients decreased with increase in water saturation as a result of the low diffusivity of gaseous oxygen in water relative to that in air and the low solubility of oxygen in water. Placement of soil covers in high saturation conditions would ensure that the flux of oxygen into tailings underneath such covers is low, resulting in low acid flux. This is confirmed by combined laboratory, field, and modeling studies.

Oxygen diffusion and dark respiration in aquatic macrophytes

Abstract. The supply of oxygen to respiring shoot tissue was investigated for three submerged macrophytes (Potamogeton crispus L., Egeria densa Planch, and Myriophyllum triphyllum Orchard). For all species, the response of oxygen uptake rates to the external O2 concentration was a rectangular hyperbola over the range 0–5.0 × 10−3m3 m−3. However, the response pattern for material with water‐infiltrated lacunar airspaces was non‐hyperbolic over this range. The change in response was interpreted as an increased substrate (O2) limitation, resulting from lower radial diffusion rates within the infiltrated material. Neither the uninfiltrated nor the infiltrated responses obeyed the linear and logarithmic formulae of the type observed for submerged macrophytes by earlier authors. These results suggest that the responses observed are affected by factors such as water velocity, internal restrictions to diffusion and the range of oxygen tensions investigated. Therefore, it is unlikely that one response formula can adequately account for the effects of oxygen concentration on submerged macrophyte oxygen uptake. The lacunar airspaces also represent a possible oxygen source for dark respiration. The consumption of oxygen from the airspaces was investigated by displacing the gas from the lacunae and measuring the subsequent increase in the rate of oxygen assimilation from the external liquid. Approximately 30% of the oxygen consumed by E. densa and P. crispus, and more than 40% of that consumed by M. triphyllum, was derived from the lacunar system. This O2 supply is a consequence of the higher oxygen concentration in the lacunae than in the external medium, due to the low solubility of oxygen in water. Storage of photosynthetically‐produced oxygen in the lacunae could not be identified during a light/dark transient, due to rate changes caused by the effects of light on the respiratory metabolism. However, O2 partial pressure gradients artificially set up between the lacunae and water equilibrated within an hour, suggesting that excess oxygen would be lost to the water within this time.

Oxygen requirement for growth of candida utilis on semisolid straw substrate

Biotechnology and BioengineeringVolume 30, Issue 5 p. 672-674 Communication To The EditorFree Access Oxygen requirement for growth of candida utilis on semisolid straw substrate Youn W. Han, Youn W. Han USDA, Southern Regional Research Center, New Orleans, Louisiana 70179Search for more papers by this author Youn W. Han, Youn W. Han USDA, Southern Regional Research Center, New Orleans, Louisiana 70179Search for more papers by this author First published: 5 October 1987 https://doi.org/10.1002/bit.260300512Citations: 7AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat References 1 N. Toyama, Biotechnol. Bioeng. Symp., 6, 207 (1976). 2 R. W. Silman, Biotechnol. Bioeng., 22, 411 (1980). 3 D. S. Chahal, Appl. Microbiol., 49, 205 (1985). 4 J. H. Kim, M. Hosobuchi, M. Kishimoto, T. Seki, T. Yoshida, H. Toguchi, and D. D. Y. Ryu, Biotechnol. Bioeng., 27, 1445 (1985). 5 L. A. Lindenfelser and A. Ciegler, Appl. Microbiol., 29, 323 (1975). 6 F. Zadrazil and H. Brunnert, Eur. J. Appl. Microbiol. Biotechnol., 11, 183 (1981). 7 G. Terui, I. Shibasaki, T. Mochizuki, and M. Takano, J. Ferment Technol., 38, 29 (1960). 8 Y. D. Hang, C. Y. Lee, and E. E. Woodams, Food Sci., 47, 1851 (1982). 9 Y. W. Han and A. W. Anderson, Appl. Microbiol., 30, 930 (1975). 10 D. C. Ulman and R. P. Tengerdy, Dev. Indust. Microbiol., 21, 425 (1980). 11 C. W. Hesseltine, Biotechnol. Bioeng., 4, 517 (1972). 12 E. Cannel and M. Moo-Young, Process Biochem., Aug-Sept. 24 (1980). 13 J. S. Knapp and J. A. Howell, Topics Enzyme Ferment. Biotechnol., 4, 85 (1980). 14 V. Carrizalez, H. Rodriguez, and I. Sardina, Biotechnol. Bioeng., 23, 321 (1981). 15 S. Sugama and N. Okazaki, J. Ferment. Technol., 57, 408 (1979). 16 N. Okazaki and S. Sugama, J. Ferment. Technol., 57, 414 (1979). 17 T. R. Green and Y. W. Han, Anal. Biochem., 82, 404 (1977). Citing Literature Volume30, Issue55 October 1987Pages 672-674 ReferencesRelatedInformation

Performance of Surface Aerators in Saline Pond Waters

Abstract Although the solubility of oxygen in water decreases as salinity increases, the rate at which an aerator transfers oxygen to water is not affected by salinity. A method for predicting aerator performance in saline water ponds is presented.

The potential use of silicon compounds as oxygen carriers for free and immobilized cells containing l-amino acid oxidase

The relatively low solubility of oxygen in water presents a problem in particular when immobilized cells are used or enzymes are applied for oxygen dependent reactions. The other main purpose is the requirement of oxygen for the increase of biomass. In this investigation the usefulness of silicon emulsions as oxygen carriers is demonstrated. In case of l-amino acid oxidase activity of immobilized cells, an increase by a factor of four was found in the presence of silicon emulsions. Likewise, growth medium enriched with silicon emulsions showed a significantly increased growth of cells inside alginate beads compared to normal growth medium.

The effect of an external magnetic field on the solubility of oxygen in water

This work describes observations on the effect of magnetic fields on the equilibrium solubility of pure oxygen in water at 25°C. It was found that neither a weak rotating magnetic field nor a uniform static magnetic field (up to 10 kG) changed the solubility of oxygen in water within experimental accuracy (1%), in contrast to previously reported data. This supports recent findings on the size of effects due to weak and moderate magnetic fields on the physico-chemical properties of pure water and/or water solutions.

The effect of a weak rotational magnetic field on oxygen solubility in water

The effect of a weak rotational magnetic field on oxygen solubility in water

The effect of pressure upon the solubility of oxygen in water: Implications of the deviation from the ideal gas law upon measurements of fluorescence quenching

The effect of pressure upon the solubility of oxygen in water compressed up to 500 atmospheres (atm) was directly measured. Pressurized aqueous solutions were allowed to equilibrate with a low pressure atmosphere (air, total pressure, 1 atm; oxygen partial pressure, 0.2 atm) across a gas-permeable, pressure-resistant Teflon membrane, and the equilibrium molar concentration of oxygen determined chemically. The solubility of oxygen in water decreased exponentially with pressure up to approximately 200 atm. At higher pressures, decreases in the molar volume of oxygen in solution resulted in a slight deviation from this initial trend. Implications of these results upon measurements of fluorescence quenching by oxygen under conditions of elevated pressure, a probe for studying the structure of macromolecules, are discussed.

On the reduction of oxygen in aqueous solution by electrolytically precipitated cadmium

The reduction of oxygen in aqueous solution by electrolytically precipitated cadmium, used in a reductor column, has been studied in two ways. First, by analysis of the effluent for the hydrogen peroxide formed as a reaction intermediate, the conditions for quantitative reduction have been found. Attention is called to the fact that an effluent free from hydrogen peroxide also implies quantitative reduction of all dissolved oxygen. The practical consequences are pointed out. A comparison is also made with some other reductors. Secondly, the oxidation of electrolytically precipitated cadmium by hydrogen ion is strongly inhibited, so at pH 7 it is possible to determine oxygen as the equivalent amount of cadmium ion produced in the reductor column. The conditions of quantitative reduction of oxygen are determined and found to be in agreement with those obtained by the first method. From the results the solubility of oxygen in water in equilibrium with air is estimated and found to agree with a published result considered as reliable. An outline is given of a method for determination of oxygen in aqueous solution by measurement of the amount of cadmium ions produced.

Applicability of Henry's Law : An Analysis of the Data of Maharajh and Walkley

THE recent report of Maharajh and Walkley1 claims that the solubility of oxygen in water is lowered by the presence of a second gas such as nitrogen. This observation conflicts with Henry's law. They base their claim upon measured solubility data which appear to show a significant interaction between the dissolved gases (each present at concentrations less than 50 p.p.m.). The purpose of this note is to demonstrate that a thermodynamic analysis of these data yields an unreasonable value for the nonideality of the aqueous solution of dissolved gases. We therefore question the validity of their data and reiterate the applicability of Henry's law to slightly soluble gases, both pure and mixed.

Determination of dissolved oxygen by the winkler method and the solubility of oxygen in pure water and sea water

AbstractValues for the solubility of oxygen in water obtained by a modification of the Winkler method are shown to be low because of losses of iodine vapour. Iodine vapour is also lost in two of the standard modifications of the Winkler method in common use, the amount lost depending on the technique of the analyst.The volatilisation of iodine can be avoided by the use of the alkaline iodide reagent of Pomeroy &amp; Kirschman; a procedure employing this reagent is described. Interference by pitrites and ferric iron may be eliminated by sodium azide and phosphoric acid respectively.The accuracy of the Winkler method, modified to prevent the loss of iodine vapour, has been confirmed using gaseous oxygen as a standard.Using the procedure recommended, determinations have been made of the solubility of atmospheric oxygen in distilled water between 0·4° and 37°, and in sea water between 2° and 27°. The results for distilled water are in excellent agreement with those of Klots &amp; Benson between 2° and 27°; the new values for sea water agree fairly well with those of Fox.In measurements of the rate of solution of oxygen, the approach to equilibrium using these values was consistent with the law of Adeney &amp; Becker.

Closure to “Solubility of Atmospheric Oxygen in Water: Twenty-Ninth Progress Report of the Committee on Sanitary Engineering Research of the Sanitary Engineering Division”

Closure to “Solubility of Atmospheric Oxygen in Water: Twenty-Ninth Progress Report of the Committee on Sanitary Engineering Research of the Sanitary Engineering Division”

Discussion of “Solubility of Atmospheric Oxygen in Water: Twenty-Ninth Progress Report of the Committee on Sanitary Engineering Research of the Sanitary Engineering Division”

Discussion of “Solubility of Atmospheric Oxygen in Water: Twenty-Ninth Progress Report of the Committee on Sanitary Engineering Research of the Sanitary Engineering Division”