Content of dissolved substances

We now consider in turn the most important biogenous elements. 

PO7 is below 0.03 mg 1. At present, the number of cases of clean waters 

The most readily biologically utilizable ions are H2PO7 originating from the salts of monovalent and bivalent cations [14,15]. However, their concentration in water usually decreases fairly rapidly since they are very unstable. They very frequently come into contact with bicarbonates and in neutral media they are transformed into a less accessible hydrogenphosphate form  

If they are not utilized by organisms the reaction goes further, and transformation to insoluble phosphate takes place  

Usually, calcium participates in the reactions with bicarbonates. The effect of iron cations on the utilizability of phosphate ions was discussed above. Phosphorus in precipitates is also partially utilizable. Plants and microorganisms are probably able to resorb phosphorus from precipitates of colloid 

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Fig. 3.33. Mineralization of world ocean (the content of dissolved substances...

Foams are dispersions of gas in a relatively small amount of liquid. When they are still on the surface of the liquid from which they were formed, they also are called froths. Bubbles range in size from about 50 pm to several mm. The data of Table 19.8 show densities of water/air foams to range from 0.8 to 24 g/L. Some dissolved or finely divided substances may concentrate on the bubble surfaces. Beer froth, for instance, has been found to contain 73% protein and 10% water. Surface active substances attach themselves to dissolved materials and accumulate in the bubbles whose formation they facilitate and stabilize. Foam separation is most effective for removal of small contents of dissolved impurities. In the treatment of waste waters for instance, impurities may be reduced from a... 

Table III H-NMR Spectral Peak-Height Ratios and Aromatic Plus Olefinic Carbon Contents of Dissolved Humic Substances...

Reducing Sugars (as glucose) Transfer about 1 g of sample, accurately weighed, into a 250-mL Erlenmeyer flask, dissolve in 10 mL of water, add 25 mL of alkaline cupric citrate TS, and cover the flask with a small beaker. Boil gently for exactly 5 min, and cool rapidly to room temperature. Add 25 mL of 10% acetic acid solution, 10.0 mL of 0.1 A iodine, 10 mL of dilute hydrochloric acid TS, and 3 mL of starch TS, and titrate with 0.1 A sodium thiosulfate to the disappearance of the blue color. Calculate the content of reducing substances (as d-glucose) (R) by the equation... 

The hydrodynamic behavior of complex particles in solution is similar to that of suspensions of solid spheres. Applying to the solutions of the PMAA-poly(ethylene glycol) complex, Einstein s equation for the viscosity of suspension of spherical particles, t]Sp/c = 2.54 q> (where tp is the volume fraction of dissolved substance) the solvent content in complex coils has been estimated33. It is about 75 vol%, i.e. the complex particles contain comparatively small quantities of the solvent in comparison with a usual random coil in solution which contains about 97-99 vol% of solvent34. ... 

Harmful substances may be present in water in either undissolved or dissolved form. Some organic compounds in water can absorb the UV light in a wavelength range of 254-280 nm. Just as turbidity detection is used to measure the total solids content, UV absorption detection at a wavelength of 254 nm can be employed to measure the total content of dissolved organic matter. The typical absorbance values at 254 nm for some important types of waters are listed in Table 1. 

This shows that IRS is a particularly powerful method for damage analysis. With this method fibres, coatings and other deposits, textile auxiliaries and substances causing stains can be identified. Chemical damage to fibres can also be detected by means of specific structural changes. All states of matter can be investigated with IR spectroscopy. Thus in damage analysis the composition of mostly liquid extraction residues is of particular interest. As well as qualitative IRS, quantitative applications are also available, where on the basis of the Lambert-Beer law the determination of the concentration of dissolved substances, the blend ratio in fibre mixtures or estimation of the comonomer content in copolymers is possible. 

With the hydrochemical method, the chemical composition of underground water together with its contents of dissolved gases and organic substances is studied. A large amount of hydrocarbons in the underground water shows a high possibility of the presence of petroleum deposit in this area. 

It follows that the content of dissolved oxygen is an important indicator of the quality of streams, as one of the first indications of surface water pollution by organic substances is a decrease in the oxygen content downstream from the source of poUution. Oxygen in water is of vital importance for fish, a concentration of 3-4 mg 1 is usually considered to be the lower limit, but this depends on the sensitivity of fish. The salmon-like fish require a concentration of approximately 6 mg... 

Normal groundwaters have a low content of dissolved solid substances, gases or microorganisms which do not satisfy any of the criteria for mineral waters. The reserves of groundwater are made up by soaking of atmospheric and surface waters, through permeable layers (infiltration), and also by the condensation of water vapour in the soil and condensation of the vapours from magma. 

Groundwaters are classified from various viewpoints (according to the degree and character of mineralization, gas content, radioactive substances, trace elements, temperature, etc.). According to the quantity of dissolved substances groundwaters are classified as follows ... 

The rated indicators, on the other hand, include the content of dissolved oxygen, active chlorine, ammonia and ammonia ions, iron, manganese, aluminium, zinc, magnesium, calcium, phosphates, nitrites, nitrates, chlorides, sulphates, humin substances, all dissolved constituents, anions of tensides, copper, hydrogen carbonates and pH value. This category also includes radioactivity characterized by total volume alpha-activity, and in surface waters also by total volume beta-activity. 

The effect of dissolved substances on the quality of the water environment cannot be individually assessed just from the viewpoint of the content of available nutrients because at the same time all biological effects of present elements and compounds play a combined role. Some substances have... 

Bikbulatov, E.S. and Skopintsev, B.A., 1974. Estimation of the total content of dissolved carbohydrates in natural waters in the presence of humic substances. Gidrokhim. Mater., 60 179—185 (in Russian). 

A simple continuous method for determining the content of dissociable substances, particularly in the case of measurements to be repeated regularly at specified intervals, is important not only for systematic but also for intermittent checking on water and its content of dissolved mineral substances. 

Inorganic dissolved substances, i. e. salts, are measured as increased conductivity. Salts are also detrimental to the process performance and potentially for the paper properties. Electrolytes reduce the swelHng potential of fibers and chloride especially leads to corrosion of machine parts [4]. The content of detrimental substances in paper miU water circuit systems depends on the input of raw materials, on the output by bleeding through waste water disposal as well as by the degree of transfer to the final paper, on the loop design, and on the presence of kidney technologies in the miU. 

A homogeneous mixture is also called a solution. Often the content of one component in a solution is totally dominating the dominating component of the solution is called the solvent. In chemistry the concept of solution includes solid, liquid and gaseous mixtures of substances. An example of a solid solution is steel made from technically pure iron Fe with a content of dissolved atomic carbon at 721 °C ferrite Fe may contain approx. 0.025 wt-% of dissolved atomic carbon. In this case the solvent is solid iron Fe. 

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