Water oxygen determination

In this reaction, iodine is liberated from a solution of potassium iodide. This reaction can be used to assess the amount of ozone in either air or water. For determination in air or oxygen, a measured volume of gas is drawn through a wash bottle containing potassium iodide solution. Upon lowering the pH with acid, titration is effected with sodium thiosulfate, using a starch solution as an indicator. There is a similar procedure for determining ozone in water. 

Figure 6.4. Percent average humidity compared with 6 0 in bone phosphate. The strong association between the two variables across the species of Australian marsupials (data from Ayliffe and Chivas 1990) and North American white-tailed deer (data from Luz ei a/. 1990) indicates that their body water oxygen isotopic composition is strongly determined by the 8"0 in their diet since plant 8 0 varies in negative correlation with humidity.

Calcium carbonate is also the main constituent of the shells of sea animals, which make their shells from elements acquired from the surrounding waters. Now, the degree of fractionation of the oxygen isotopes as well as the formation of mineral carbonates and of animal shells in sea waters are determined on the basis of the temperature-dependent fractionation of the isotopes of oxygen the oxygen isotope composition of these materials reflects, therefore, the temperature at the time of their formation. Thus determining the isotope ratio between the stable isotopes of oxygen... 

The Gd-H distance, /-GdH, which enters at the inverse sixth power into the expression of inner-sphere relaxivity, is a difficult parameter to obtain experimentally. It is generally estimated on the basis of Gd-coordinated water oxygen distances, determined by solid-state X-ray analysis. Solid-state distances are good estimates of the aqueous solution state, as was experimentally proven by an X-ray absorption fine-structure study on [Gd(D0TA)(H20)] and [Gd(DTPA)(H20)]2, which gave identical values for the Gd-0 distances for both complexes in solid and solution states.20... 

Reaeration in sewer networks the presence of dissolved oxygen in wastewater of sewer systems determines if, and to what extent, aerobic and anaerobic processes proceed. The air-water oxygen transfer (the reaeration) determines the potential of aerobic transformation and corresponding removal of wastewater components in many sewer... 

Determination of reaeration relies on the measurement of the air-water oxygen transfer coefficient (Section 4.4.2). Measurement of this coefficient — the reaeration coefficient — in gravity sewer lines follows basically the methods that have been developed for and applied in rivers. Methods for determination... 

Jensen and Hvitved-Jacobsen (1991) developed a direct method for the determination of the air-water oxygen transfer coefficient in gravity sewers. This method is based on the use of krypton-85 for the air-water mass transfer and tritium for dispersion followed by a dual counting technique with a liquid scintillation counter (Tsivoglou et al 1965,1968 Tsivoglou andNeal, 1976). A constant ratio between the air-water mass transfer coefficients for dissolved oxygen and krypton-85 makes it possible to determine reaeration by a direct method. Sulfur hexafluoride, SF6, is another example of an inert substance that has been used as a tracer for reaeration measurements in sewers (Huisman et al., 1999). 

The main difficulty of this method is the unknown value of the term X (l + p /3) and therefore the value for pure water is often used. On the other hand, it has the advantage that the measurement is directly performed on a solution of the Gd(III) complex and that the rotational correlation time of the Gd-coordinated water oxygen vector is actually determined 12)-,... 

The presence of water does not only create conditions for the existence of an electrolyte, but it acts as a solvent for the dissolution of contaminants [10], Oxygen plays an important role as oxidant element in the atmospheric corrosion process. The thickness of the water layer determines the oxygen diffusion toward the metallic surface and also the diffusion of the reaction products to the outside interface limited by the atmosphere. Another aspect of ISO definition is that a metallic surface is covered by adsorptive and/or liquid films of electrolyte . According to new results, the presence of adsorptive or liquid films of electrolyte perhaps could be not in the entire metallic surface, but in places where there is formed a central anodic drop due to the existence of hygroscopic particles or substances surrounded by microdrops where the cathodic process takes place. This phenomenon is particularly possible in indoor conditions [15-18],... 

Risk labels, lATA/ICAO, 751-3 Risk phrases, 621, 748, 749 River water, peroxide determination, 642 RNA, ozone disinfection, 616 ROS see Reactive oxygen species Rose Bengal sensitized photooxidation, 890 Rotational barriers, regioselective allylic hydroperoxide formation, 836, 847-9 Rotational isomers, peroxynitrous add, 8-9 Rotational spectra, ozonides, 721, 722-3 RP-HPLC, hydrogen peroxide determination, 627... 

The type of feed gas used, air or oxygen, determines the achievable ozone gas concentration and the gas preparation requirements. The higher the oxygen content, the higher the ozone concentration possible. Ambient air contains 02 in about 21 vol % (at STP) and is thus a cheap and ubiquitous resource for ozone production. Its main use and advantage is in applications where large mass flows are required at comparatively low ozone gas concentrations, e. g. in drinking water ozonation systems. 

Figure 6. The degree of pyritization, defined as the fraction of reactive iron present as pyrite, is a measure of the extent to which available iron has reacted with sulfur (226). In lake sediments, iron monosulfides frequently are as abundant as pyrite and hence were included with pyrite in the values calculated for surface sediments from 13 lakes and presented here. Even this correction neglects Fe(II) that may have been reduced by sulfide but may be present as siderite. Availability of iron appears to be more important than bottom-water oxygenation in determining the degree of pyritization. In the right-hand graph, darkened squares represent sediments known to experience seasonal anoxia only the uppermost point experiences permanent anoxia. (Data are from references 30, 34, 56, and 61.)...

It has been suggested that sulfones represent a stable form of oxidized organic S (184). Because of a lack of analytical techniques, such forms have been tentatively identified in only two studies (32, 207). Additional data are needed to determine if the abundance of these forms can serve as an indicator of bottom-water oxygenation. 

International Standard Organization. 1983. Water quality. Determination of dissolved oxygen. Iodometric method. ISO 5813. International Organization for Standardization, Case Postale 56, CH-1211, Geneva 20 Switzerland. 

Volborth, A., and H. E. Banta Oxygen Determination in Rocks, Minerals, and Water by Neutron Activation. Anal. Chem. 35, 2203 (1963). 

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