Water dissolved oxygen

Water Treatment. Sodium sulfite is an agent in the reduction of chlorine or oxygen in water. Dissolved oxygen in boiler water tends to enhance pitting and other types of corrosion. In boilers operated at below 4.82 MPa (700 psi), a residual concentration of 30 ppm of sodium sulfite is generally effective. Catalytic amounts of cobalt are often added to accelerate the reaction of oxygen with sulfite (321,322) (see Water, industrial water treatment). 

Oxygen corrosion usually takes the form of deep pitting and involves both tuberculation and differential aeration corrosion mechanisms. The BW commonly is brown and murky, and chemical treatment reserves usually are very low or absent. The source of the oxygen is either MU water dissolved oxygen (DO) or air in-leakage. 

Zakharov I.A., Grishaeva T.I., Determination of microconcentrations of water-dissolved oxygen by quenching of the adsorbate afterglow, Zh. Anal. Khim. 1980 35 481 and refs, cited. 

Thianes and thiolanes react readily with molecular oxygen to form sulfoxides and aerial or water-dissolved oxygen can partially oxidize the sulfides. Consequently, the sulfoxide to sulfide class ratio may serve as an indicator of the redox conditions in the reservoir of oil sand formations. 

A lingering limitation with the present generation of reverse osmosis membranes is their limited resistance to chemical attack. In particular, membranes derived from polyamides, polyureas, and other nitrogen-containing polymers are susceptible to oxidative degradation by chlorine—the most widely used disinfectant to pretreat feed waters. Dissolved oxygen can also damage reverse osmosis membranes when catalyzed by trace heavy metals. Successful development of oxidation-resistant membranes will help reduce the complexity and costs associated with the elaborate pretreatment now required. 

Dissolved oxygen overall mass transfer coefficient of tap or distilled water Dissolved oxygen overall mass transfer coefficient of tap or distilled water at standard conditions... 

Figure 18.12 Bar graph of N-recycling efficiency as a function of bottom water dissolved oxygen concentration. Bars were based on Chesapeake Bay data reported in Kemp et al. (1990) and Cornwell (unpublished data). Solid dots were based on data from Rysgaard-Petersen et al. (1994) collected from Vilhelmsborg So, Denmark. Terms in the recycling efficiency calculation (y-axis) are Ffjj — flux of N2 from sediments = flux of ammonium from sediments FjsjOj flux of nitrate from sediments.

Historic data on Secchi disk depth in the northern Adriatic Sea in 1911 through the present, with few interruptions of data collection, provide a measure of water transparency that could be interpreted to depict surface water productivity. These data coupled with surface and bottom water dissolved oxygen content determined by Winkler titrations and nutrient loads outline the sequence of eutrophication in the northern Adriatic Sea. Similar historical data from other coastal areas around the world demonstrate a decrease in water clarity due to phytoplankton production in response to increased nutrient loads that are paralleled by declines in water column oxygen levels. 

Boiler feed treatment also must remove oxygen and alkalinity from the water. Dissolved oxygen leads directly to corrosion, and it is most dangerous when corrosion takes the form of pitting. Alkalinity refers primarily to carbonates and bicarbonates. These... 

As for metal oxides, several different procedures have been proposed for the deposition of the relevant nanostructures, e.g., CoO, MnO c, CeO . and TiO NPs [199]. The most common procedure consists of inducing variation of the solution pH in close proximity to the substrate surface, by the reduction of water, dissolved oxygen, or nitrate ions. The local increment of the pH value leads oxide/hydroxide species to precipitate onto the electrode surface [197]. 

At ordinary temperatures in neutral or near neutral water, dissolved oxygen is necessary for appreciable corrosion of iron. In air-saturated water, the initial corrosion rate may be high. This rate may diminish over a period of time as the iron oxide film is formed and acts as a barrier to oxygen diffusion. Since the diffusion rate at steady state is proportional to oxygen concentration, it follows that the corrosion rate of iron is also proportional to oxygen concentration. 

Commonly encountered chemical quenchers are water, dissolved oxygen, salts, acids, chlorinated hydrocarbons, and peroxides. 

Corrosion is the unwanted chemical reaction of a metal with its environment, resulting in its continued degradation to oxides, hydroxides, or other compounds. Tissue fluid in the human body contains water, dissolved oxygen, proteins, and various ions such as chloride and hydroxide. As a result, the human body presents a very aggressive environment for metals used for implantation. Corrosion resistance of a metallic implant material is consequently an important aspect of its biocompatibility. 

Water possesses several unique properties, one being its ability to dissolve to some degree every substance occurring on the earth s crust and in the atmosphere. Because of this solvent property, water typically contains a variety of impurities. These impurities are a source of potential trouble through deposition of the impurities in water lines, in boiler tubes, and on products which are contacted by the water. Dissolved oxygen, the principal gas present in water, is responsible for the need for costly replacement of piping and equipment as a result of its corrosive attack on metals with which it comes in contact. 

When wholemeal flour is mixed with water, dissolved oxygen is consumed due to a lipoxygenase-catalysed peroxidation of F-puFA . The fatty acid oxidation products that are formed in low amounts in aqueous suspensions of white flour have been described previously. This paper illustrates the more substantial lipid peroxidation reactions that occur in aqueous suspensions and doughs of wholemeal flour and points out several important practical implications of this process. 

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