Chlorides levels

To prepare a USP-grade Epsom salt, higher purity MgO or Mg(OH)2 is used. USP and food grades require low chloride levels, limiting allowable chloride content of the MgO to 0.08 wt %. Trace impurities including iron and aluminum are precipitated using excess MgO. EoUowing crystallization, the Epsom salt is washed free of mother Hquor. 

Calcium sources, such as gypsum and lime, promote cation exchange from sodium clay to a less-sweUing calcium clay. Calcium concentrations ate normally low (<1000 mg/L) and osmotic swelling is only reduced if other salts are present. Calcium chloride has been used infrequently for this purpose but systems are available that allow high calcium chloride levels to be carried in the mud system (98). 

Hydrogen chloride is produced when PVC bums. A series of tests for the Federal Aviation Administration studied this issue. In those studies, test animals were able to survive exposures to hydrogen chloride reaching 10,000 ppm (190). More recent studies indicate less of a potential for delayed effects on lung function than expected (191). In a typical fire, hydrogen chloride levels rarely exceed 300 ppm, a fact confirmed by the Boston Fire Department and Harvard University (192). In hundreds of autopsies conducted on fire victims in the United States, not one death has been linked to the presence of PVC. 

Ion Selective Electrodes Technique. Ion selective (ISE) methods, based on a direct potentiometric technique (7) (see Electroanalytical techniques), are routinely used in clinical chemistry to measure pH, sodium, potassium, carbon dioxide, calcium, lithium, and chloride levels in biological fluids. 

More details of other factors that affect the critical pitting potential have been discussed by Uhlig and his co-workers" . They indicated that for stainless steel the critical pitting potential decreased with increasing concentration of chloride ion. At a fixed chloride level, passivating ions in solution, such as sulphate and nitrate, etc., cause the pitting potential to become more positive at a sufficient concentration these ions totally inhibited pitting, as shown in Fig. 19.40 for SO and CIO . 

Table XII provides a synopsis of the findings. Figure 2 depicts the change in hot spot location caused by increased chloride levels. Analysis...

The chloride level was raised to above 5 ppm in the feed gas because the hot spot had moved down to the 69% level and remained there. Note that percent conversion changed significantly only when the hot spot reached the bottom of the bed. When the chloride was removed, neither hot spot location nor percent conversion improved. 

It is important that the tube surfaces be kept clean to avoid the initiation of corrosion. Regular waterside inspections and, if necessary, chemical cleaning of high-pressure equipment is recommended. The level of chloride that may be tolerated in such boilers during steady operation depends on the type of treatment employed. Where all-volatile alkaline treatments (AVT) are used, then the chloride levels should be lower than where nonvolatile alkalis (NVAT), such as sodium hydroxide and sodium phosphate, are used. The value may vary, depending on whether the boiler is coal-fired or oil-fired. 

The final effluent from the H2O2 process is basically clean whereas the chlorine based oxidants impart high chloride levels to the stream. 

Now consider a psychiatric patient who presents with a pH of 7.50, a PaC02 of 20 mm Hg (2.7 kFh), an HC03 of 16 mEq/L (mmol/L), a sodium concentration of 140 mEq/L (mmol/L), and a chloride level of 103 mEq/L (mmol/L). Because this person is alkalemic, the low PaC02 is the primary disturbance and represents respiratory alkalosis. If this disturbance is a chronic respiratory alkalosis with metabolic compensation, the expected AHC03 is 0.4 x APaC02 (in millimeters of mercury) or 0.4 x 20, which is 8 mEq/L (mmol/L). As such, the predicted HC03 concentration should be 24 mEq/L (mmol/L) [normal] - 8 mEq/L (mmol/L) [expected compensation] or 16 mEq/L (16 mmol/L). 

Figure 7.8. Swiss chard Cd concentrations as affected by chloride levels in soils (modified from Weggler-Beaton et al., 2000)...

A number of clinical symptoms characterize cystic fibrosis. Predominant among these is the presence of excess sodium chloride in cystic fibrosis patient sweat. Indeed, measurement of chloride levels in sweat remains the major diagnostic indicator of this disease. Another characteristic is the production of an extremely viscous, custard-like mucus in various body glands/organs that severely compromises their function. Particularly affected are ... 

Brookfield, Ct., SPE, 2004, Paper 3, pp.7, CD-ROM, 012 RESIDUAL VINYL CHLORIDE LEVELS IN U.S. PVC RESINS AND PRODUCTS - HISTORICAL PERSPECTIVE AND UPDATE... 

Although a number of methods have been proposed for the biological monitoring of occupational methylene chloride exposure, measurement of urinary methylene chloride levels may be the most suitable. The measurement of urinary methylene chloride is nonin-vasive, not influenced by smoking as are COHb or carbon monoxide levels in alveolar air, and may reflect cumulative exposures more accurately "... 

This may be of relevance if a possible implementation mode involves integrated ion-exchange/catalytic denitrification process where NaCl is used as background electrolyte. High chloride levels may also lead to catalysts poisoning, possibly due to metal corrosion. Although sulfide is also... 

Table 6.8 Dosage requirements for calcium nitrite at different chloride levels (Berke and Weil)...

Serum phosphorus, calcium, bicarbonate, and chloride levels... 

For incorporation of crown ethers and cryptates into the RTV encapsulant system as sodium and potassium ion scavengers, the total ionic contaminants must first precisely be determined. Atomic absorption is used to measure these ions in commercial silicone RTVs and silicone fluids. Values of "10 ppm for sodium and potassium were obtained in the best samples. Chloride level was determined by potentiometric titration of the silicone with AgN03. A quantity of ion trap (either crown ethers or cryptates) was then added to the RTV silicone encapsulant, and its molar concentration was equal to the combined sodium and potassium contaminant levels. 

Reduction of the sodium chloride level can result in taste problems and flavour shifts. There are several approaches to maintain salt taste. Most often, potassium chloride is used, because it shows the most prominent salty taste of those applicable inorganic salts. Lithium chloride is the most salty salt but cannot be used for toxicological reasons. Most consumers, however, complain about the bitter, chalky taste of KCl-containing formulations. Development of sodium-reduced products using mineral salts is a challenge and the whole product formula has often to be adapted [25]. Therefore, the main focus of the research was the search for masking compounds or technologies to cover the bad taste of KCl, e.g. phenolic acids and derivatives [26] and lactisol [27]. 

Figures 4 and 5 for Vaq/Vorg = 5.0 show that removal of organic lead corresponds closely to that which would be obtained for a theoretical 1 1 complex in the absence of sodium chloride. Variations in extraction efficiency are observed for different solvents, but for all of the solvents employed a ratio Cr/Cl = 1.0 is sufficient to reduce an initial triethyl lead chloride level of 10 ppm to <1 ppm. A comparison of solvents used suggests an approximate order of effectiveness (corresponding to solubility of the organo-lead complex Hs PbSCSN Hs and also the neutral species Hs PbCl0 in the solvent) of the form shown in Table IV.

While organo-lead removal is a function of the solvent employed, the level to which the concentration can be reduced depends upon the interaction of the variables Vaq/Vorg and Cr/Cl- This effect is clearly illustrated in Table V for the solvent C15H32 at an initial triethyl lead chloride level of 27 ppm. 

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