Sodium river water

Figure 13.15 shows the influence of adding sodium sulphite on the chromatogram of a river water sample. 

Microbes could not break down branch-chain detergents, so they left foam in river water. They were replaced by straight-chain alkyl benzene sulfonates, such as sodium dodecylbenzene-sulfonate and sodium xylenesulfonate. 

NPEOs and OPEOs (rcEo = 3-10) as industrial blends or standard compound (Triton X-100), respectively, were separated together with linear alkylbenzene sulfonates (LASs) on a Ci-RP column [10]. The intensive ions that could be observed in the spectra were mono-, di- and tri-sodium adduct ions [M + Na]+ (m/z 581), [M + 2Na]+ (m/z 604) and [M + 3Na]+ (m/z 626) of the EO7 homologue. The intensity of the molecular [M + H]+-ion, however, was small compared with the sodium adduct ions. The compounds had been concentrated prior to separation on Cis and SAX SPE cartridges. Samples from river water were handled in the same way. 

Most cation exchange occurs in estuaries and the coastal ocean due to the large difference in cation concentrations between river and seawater. As riverborne clay minerals enter seawater, exchangeable potassium and calcium are displaced by sodium and magnesium because the Na /K and Mg /Ca ratios are higher in seawater than in river water. Trace metals are similarly displaced. 

The other reason why the average salinity of seawater is 35%o lies in the fundamental chemistry of major ions. For example, the sevenfold increase in the Na /K ratio between river water and seawater (Table 21.8) reflects the lower affinity of marine rocks for sodium as compared to potassium. In other words, the sodium sink is not as effective as the one for potassium. Thus, more sodium remains in seawater, with its upper limit, in theory, being controlled by the solubility of halite. Likewise, the Ca /Mg ° ratio in seawater is 12-fold lower than that of river water due to the highly effective removal of calcium through the formation of biogenic calcite. 

Sodium perborate, hydrogen peroxide determination, 652 Soil, analysis of peroxides, 608 Solar radiation, peroxides in river water,... 

Also called vapour-phase interferences or cation enhancement. In the air-acetylene flame, the intensity of rubidium absorption can be doubled by the addition of potassium. This is caused by ionization suppression (see Section 2.2.3), but if uncorrected will lead to substantial positive errors when the samples contain easily ionized elements and the standards do not. An example is when river water containing varying levels of sodium is to be analysed for a lithium tracer, and the standards, containing pure lithium chloride solutions, do not contain any ionization suppressor. 

Figure 9. Analysis of anions and cations in river water using tartaric acid/18-crown-6/methanol-water eluent with a carboxylated polyacylate stationary phase in the protonated form. Ions 1) sulfate 2) chloride 3) nitrate 4) eluent dip 5) unknown 6) sodium 7) ammonium 8) potassium 9) magnesium 10) calcium (from ref. 80)...

Dressman [694] used the Coleman 50 system in his determination of dialkylmercury compounds in river waters. These compounds were separated in a glass column (1.86mx2mm) packed with 5% of DC-200 plus 3% of QF-1 on Gas Chrom Q (80-100 mesh) and temperature programmed from 70 to 180°C at 20°C min-1, with nitrogen as carrier gas (50mL min ). The mercury compound eluted from the column was burnt in a flame ionisation detector, and the resulting free mercury was detected by a Coleman mercury analyser MAS-50 connected to the exit of the flame ionisation instrument down to 0.1 mg of mercury could be detected. River water (1L) was extracted with pentane-ethyl ether (4 1) (2 ><60mL). The extract was dried over sodium sulphate, evaporated to 5mL and analysed as above. 

In this method, arsine and methylarsines produced by sodium borohydride reduction are collected in n-hcptanc (-80°C) and then determined. The limit of detection for a 50mL sample was 0.2-0.4pg L 1 of arsenic. Relative standard deviations ranged from 2% to 5% for distilled water replicates spiked at the lOpg L 1 level. Recoveries of all four arsenic species from river water ranged from 85% to 100%. 

The definition of the sea boundary of the mouth area is related to the term mouth-mixing zone. Water salinity within this zone increases from the salinity inherent in river water (usually 0.2-0.5%o) to the salinity of seawater (usually 10-40%o in different seas). The salt composition of water radically changes within the mixing zone river water of hydrocarbonate class and calcium group transforms into seawater of chloride class and sodium group. 

No iron salts (or salts of other heavy metals) should be allowed to come into contact with the product either during the operation or when storing, as they cause it to decompose with the liberation of oxygen [see equation (XIII-22)]. For this reason it is better to use steam condensate for the preparation of the caustic solution instead of river water. Sodium hypochlorite prepared in this way is a solution which contains 150 grams of active chlorine per litre as well as 140 g of NaCl, 3 to 5 g of NaOH, 5 to 8 g of Na COg and maximum of 0.01 g Fe. 

For example, a 3 per cent, solution of common salt at 10° C. is much more corrosive than tap water at the same temperature but as the temperature rises the relative corrosivity falls, so much so that at 21° C. the salt solution is the 1 ess corrosive of the two. Since sea water contains some 3 per cent, of sodium chloride, it is of interest to inquire into the effect of temperature upon its corrosive powers. The few laboratory tests that have been carried out on the subject2 indicate that at temperatures below 13° C. sea water is more corrosive than tap water, whilst at all higher temperatures it is less so. Now, in the western part of the tropical Pacific Ocean a temperature of 32° C. is sometimes attained, and in the Red Sea and Persian Gulf temperatures of 34 4° C. and 35 5° C. respectively have been registered. Such waters should therefore prove less corrosive than river waters at the same temperatures. 

Titrations were performed on untreated, filtered, and UV-treated filtered river water samples at in situ and adjusted pH values. The effect of pH on copper speciation was investigated by titration of filtered Newport River water at pH 7.0 and filtered Newport and Neuse waters at pH 8.0. Newport River water was adjusted to pH 7.0 by decreasing the partial pressure of CO2 from the initial ambient value of about 10 times the atmospheric level. To adjust the pH to 8.0, sodium bicarbonate was added to bring the river water samples to a concentration of 0.5 mM with subsequent adjustment of Pc02 Titrations were also conducted at pH 7,0 in model solutions consisting of 0.01 KNO3 and 0.1 mM NaHC03 with and without the addition of 0.75 histidine to test electrode behavior in solutions of known chemistry. 

Table 3 lists examples of more than a dozen different chemical types of river water. Although Ca and HCO j" are generally dominant, Mg dominance over Ca + can be found in rivers draining various lithologies such as basalt, peridotite, serpentinite, dolomite, coal, or where hydro-thermal influence is important (Semliki). Sodium may dominate in sandstone basins, in black shales (Powder, Redwater in Montana), in evaporitic sedimentary basins (Salt), in evaporated basins (Saoura), and where hydrothermal and volcanic influence is important (Semliki, Tokaanu). rarely exceeds 4% of cations, except in some clayey sands, mica schists, and trachyandesite it exceeds 15% in extremely dilute waters of Central Amazonia and in highly mineralized waters of rift lake outlets (Semliki, Ruzizi). 

The abundances of trace elements in rivers depends both on their abundances in the continental crust and their mobility during weathering and transport. In order to depict a global solubility trend of trace elements, dissolved concentrations (Cw) are normalized to those of the upper continental crust (Cc) (Figure 2). Data from the continental crust are from Li (2000). In this figure, major elements in river waters are also shown and all normalized concentrations are compared to the value for sodium. It is important to note that the Cw/Cc ratio is a global mobility index rather than a solubility index because, as will be shown below, a number of very different processes contribute to the occurrence of trace elements in river dissolved load. In addition, for a... 

The mean concentrations of constituents of seawater are determined not by simple distillation of river water but by their various mechanisms of removal from the ocean. The dominant cation in river water, e.g., is calcium from weathering of carbonate and silicate rocks, whereas the dominant cation in the ocean is sodium, because there are no efficient loss mechanisms for sodium analogous to the formation of CaC03 as a loss... 

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