scholarly journals An Experimental Study of the Solubility and Speciation of MoO3(s) in Hydrothermal Fluids at Temperatures up to 350°C

2020 ◽  
Vol 115 (3) ◽  
pp. 661-669 ◽  
Author(s):  
Linbo Shang ◽  
A. E. Williams-Jones ◽  
Xinsong Wang ◽  
A. Timofeev ◽  
Ruizhong Hu ◽  
...  
Keyword(s):  
Dominant Species ◽  
High Salinity ◽  
Molybdenum Trioxide ◽  
Equilibrium Constants ◽  
Water Vapor Pressure ◽  
Hydrothermal Systems ◽  
Saturated Water Vapor ◽  
Saturated Water ◽  
Increasing Temperature ◽  
Aqueous Species

Abstract The solubility of molybdenum trioxide (MoO3(s)) in aqueous solutions has been investigated experimentally at 250°, 300°, and 350°C and saturated water vapor pressure, and total Na concentrations ranging from 0 to 3 molal (m). Results of these experiments show that the solubility of MoO3(s) increases with increasing temperature and at 350°C can reach several thousand parts per million at high salinity (>1 m NaCl). At low Na+ activity, MoO3(s) dissolves dominantly as HMoO4,− whereas at high Na+ activity, the dominant species is NaHMoO40. The two dissolution reactions are MoO3(s)+H2O=HMoO4−+H+(1) and MoO3(s)+H2O+Na+=NaHMoO40+H+.(2) The values of the logarithms of the equilibrium constants for reaction (1) are –5.20 ± 0.12, –5.31 ± 0.17, and –5.50 ± 0.09 at 250°, 300°, and 350°C, respectively, and for reaction (2) the values are –3.40 ± 0.11, –3.25 ± 0.19, and –2.97 ± 0.09 for the same temperatures. In combination, these equilibrium constants yield equilibrium constants for the reaction relating the two aqueous species: Na++HMoO4−=NaHMoO40.(3) The values of the logarithms of the equilibrium constants for reaction (3) are 1.80 ± 0.16, 2.06 ± 0.25, and 2.53 ± 0.13 at 250°, 300°, and 350°C, respectively. Calculations, based on the results of this study and thermodynamic data available for other species, suggest strongly that in ore-forming hydrothermal systems, molybdenum is transported mainly as NaHMoO40 and deposits as molybdenite in response to cooling and possibly a reduction in fO2.

Replication of Wet Objects and Cells

1974 ◽  
Vol 32 ◽  
pp. 102-103
Author(s):  
S. Basu ◽  
D. F. Parsons
Keyword(s):  
Water Vapor Pressure ◽  
High Vacuum ◽  
Polystyrene Latex ◽  
Vacuum System ◽  
Saturated Water Vapor ◽  
Replication Method ◽  
New Methods ◽  
Saturated Water ◽  
Water Vapors ◽  
Intermediate Chamber

We are approaching the invasiveness of cancer cells from the studies of their wet surface morphology which should distinguish them from their normal counterparts. In this report attempts have been made to provide physical basis and background work to a wet replication method with a differentially pumped hydration chamber (Fig. 1) (1,2), to apply this knowledge for obtaining replica of some specimens of known features (e.g. polystyrene latex) and finally to realize more specific problems and to improvize new methods and instrumentation for their rectification. In principle, the evaporant molecules penetrate through a pair of apertures (250, 350μ), through water vapors and is, then, deposited on the specimen. An intermediate chamber between the apertures is pumped independently of the high vacuum system. The size of the apertures is sufficiently small so that full saturated water vapor pressure is maintained near the specimen.

Selective hydrothermal reductions using geomimicry

2019 ◽  
Vol 21 (15) ◽  
pp. 4159-4168 ◽  
Author(s):  
Christiana Bockisch ◽  
Edward D. Lorance ◽  
Garrett Shaver ◽  
Lynda B. Williams ◽  
Hilairy E. Hartnett ◽  
...  
Keyword(s):  
Water Vapor ◽  
Vapor Pressure ◽  
Iron Powder ◽  
Water Vapor Pressure ◽  
Saturated Water Vapor ◽  
Saturated Water ◽  
Powdered Nickel

Reduction of carbon–carbon π-bonds has been demonstrated using iron powder as the reductant and simple powdered nickel as the catalyst in water as the solvent at 250 °C and the saturated water vapor pressure, 40 bars.

Experimental study of ZrF62– stability in hydrothermal solutions at 90–255 ᵒC

2019 ◽  
pp. 107-111
Author(s):  
M. E. Tarnopolskaya ◽  
A. Yu. Bychkov
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Water Vapor ◽  
Vapor Pressure ◽  
Dissociation Constants ◽  
Water Vapor Pressure ◽  
Hydrothermal Solutions ◽  
Free Energies ◽  
Saturated Water Vapor ◽  
Saturated Water

The solubility of fluorite in HCl and HF solutions with a variable concentration of Zr at 90, 155, 205 and 255 ᵒC and the pressure of saturated water vapor were investigated. The results showed that the solubility of fluorite increases with increasing concentration of zirconium. Using the OptimA program, the free energies of the ZrF62– complex were determined from the experimental data, from which the dissociation constants of the reaction ZrF62– =Zr4+ + 6F- were calculated. The pK values were 29,86±0,13; 34,03±0,062; 38,28±0,033; 40,94± 0,079 at 90, 155, 205 and 255 ᵒС (saturated water vapor pressure).

scholarly journals AN OVERWIEW AND ANALYSIS OF DEPENDECIES FOR DETERMINING THE SATURATION PRESSURE OF WATER VAPORS

2019 ◽  
Vol 7 (4) ◽  
pp. 300-306
Author(s):  
Petko Tsankov ◽  
Ivan Binev
Keyword(s):  
Water Vapor ◽  
Vapor Pressure ◽  
Partial Pressure ◽  
Water Vapor Pressure ◽  
Saturation Pressure ◽  
Saturated Water Vapor ◽  
Important Indicator ◽  
Saturated Water ◽  
Water Vapors ◽  
Water Vapor Saturation Pressure

This paper reviews, describes and analyzes the accuracy of 24 dependencies for determining the partial pressure of saturated water vapor. An important indicator of this process is the partial pressure of water vapor in the air, and its maximum value is called saturated water vapor pressure or water vapor saturation pressure, or partial saturated water vapor pressure. The assessment is made against the accepted dependency of Hardy-Wexler. Conclusions and recommendations for simple and highly accurate dependencies ps = f(t) were made.

ESEM - A multipurpose surface Electron Microscope

1986 ◽  
Vol 44 ◽  
pp. 632-633 ◽  
Author(s):  
G.D. Danilatos
Keyword(s):  
Electron Microscope ◽  
Room Temperature ◽  
Environmental Scanning ◽  
Gas Composition ◽  
Saturated Water Vapor ◽  
Surface Electron ◽  
Current State ◽  
Saturated Water ◽  
New Type ◽  
Temperature And Pressure

Over recent years a new type of electron microscope - the environmental scanning electron microscope (ESEM) - has been developed for the examination of specimen surfaces in the presence of gases. A detailed series of reports on the system has appeared elsewhere. A review summary of the current state and potential of the system is presented here.The gas composition, temperature and pressure can be varied in the specimen chamber of the ESEM. With air, the pressure can be up to one atmosphere (about 1000 mbar). Environments with fully saturated water vapor only at room temperature (20-30 mbar) can be easily maintained whilst liquid water or other solutions, together with uncoated specimens, can be imaged routinely during various applications.

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