Removal of sodium

In a patented process, a stirred suspension of sodium sulfite is continuously treated with aqueous sodium hydroxide and a sulfur dioxide-containing gas at 60—85°C, and 96% pure anhydrous sodium sulfite is removed by filtration (336). In another continuous one-step process, substantially anhydrous sodium carbonate and sulfur dioxide are concurrently introduced into a saturated solution of sodium sulfite at pH 6.5—7.6 and above 35°C with continuous removal of sodium sulfite (337). 

The application of the Chelex 100 resin separation and preconcentration, with the direct use of the resin itself as the final sample for analysis, is an extremely useful technique. The elements demonstrated to be analytically determinable from high salinity waters are cobalt, chromium, copper, iron, manganese, molybdenum, nickel, scandium, thorium, uranium, vanadium, and zinc. The determination of chromium and vanadium by this technique offers significant advantages over methods requiring aqueous final forms, in view of their poor elution reproducibility. The removal of sodium, chloride, and bromide allows the determination of elements with short and intermediate half-lives without radiochemistry, and greatly reduces the radiation dose received by personnel. This procedure was successfully applied in a study of... 

Kvaerner Chemetics have developed a novel, patented process [1] for the removal of multivalent anions from concentrated brine solutions. The prime market for this process is the removal of sodium sulphate from chlor-alkali and sodium chlorate brine systems. The sulphate ion in a brine solution can have a detrimental effect on ion-exchange membranes used in the production of chlorine and sodium hydroxide consequently tight limits are imposed on the concentration of sulphate ions in brine. As brine is continuously recycled from the electrolysers back to the saturation area, progressively more and more sulphate ions are dissolved and build up quickly in concentration to exceed the allowable process limits. A number of processes have been designed to remove sulphate ions from brine. Most of these methods are either high in capital or operating cost [2] or have large effluent flows. 

The removal of sodium and other metal ions is very important to obtain pure silica gels. The next step in both routes is ... 

Puchades, M. Westman, A. Blennow, K. Davidsson, P. Removal of Sodium Dode-cyl Sulfate From Protein Samples Prior to MALDI-MS. Rapid Commun. Mass Spectrom. 1999,13, 344-349. 

Lithium may be recovered from natural chloride brines. Such recovery processes may require additional steps depending on the magnesium and calcium content of the brine. The process involves evaporation of brine, followed by removal of sodium chloride and interferring ions such as calcium and magnesium. Calcium is removed by precipitation as sulfate while magnesium is removed by treating the solution with lime upon which insoluble magnesium hydroxide separates out. Addition of sodium carbonate to the filtrate solution precipitates hthium carbonate. 

The complete removal of sodium is indicated by the lack of formation of blue coloration when the solution is swirled over the upper walls of the flask. 

Consequently, the use of potassium perdisulphate has been suggested to effect the removal of sodium thiosulphate from photographic negatives after fixing. 8... 

For optimal performance of dual function isomerization catalysts based on zeolite Y or mordenite, extensive removal of sodium is necessary. The finished catalyst must be highly crystalline, and the finely dispersed metallic hydrogenation function should be well distributed throughout the catalyst particles. The proposed mechanism explains the stabilizing influence on conversion and the suppression of cracking reactions by addition of the metallic hydrogenation function to the active acidic catalyst base. 

Hager, D. A. and Burgess, R. R. (1980) Elution of proteins from sodium dodecyl sulfate-polyacrylamide gels, removal of sodium dodecyl sulfate, and renaturation of enzymatic activity results with sigma subunit of Escherichia coli RNA polymerase, wheat germ DNA topoisomerase, and other enzymes. Anal Biochem 109, 76-86. 

Frequently, ion-exchange rosins are used in fixed-bed processing equipment lor softening and deionizing water. Equations lor the removal of sodium chloride from water are as follows. 

Preparation of Trinitroanisol. Thirty-five grams of picryl chloride is dissolved in 400 cc. of methyl alcohol with warming under reflux, and the solution is allowed to cool to 30-35°. A solution of 23 grams of sodium hydroxide in 35 cc. of water is added slowly through the condenser, while the liquid is cooled, if need be, to prevent it from boiling. The mixture is allowed to stand for an hour or two. The red precipitate is filtered off, washed with alcohol, and stirred up with water while strong hydrochloric acid is added until all red color has disappeared. The slightly yellowish, almost white, precipitate, washed with water for the removal of sodium chloride, dried, and recrystallized from methyl alcohol, yields pale yellow leaflets of trinitroanisol, m.p. 67-68°. From anhydrous solvents the substance separates in crystals which are practically white. 

A two-stage ED process was also proposed to recover succinic acid [HOOC (CH2)2COOH] from sugar- and triptophane-based fermentation media (Glassner and Datta, 1992). The broth was previously concentrated via ED using monopolar membranes and then separated into sodium hydroxide-and free succinic acid-rich streams using bipolar membranes. Further removal of sodium cations and sulfate anions was achieved using weakly acid and -basic IER. 

In this model measurable constitutive activity (elevated levels of [R G]) can be achieved by increasing the concentration of R and/or G. Another way in which constitutive activity can be produced is through alteration of the J or M allosteric constants—for example, by the removal of sodium ions or by introducing different point mutations into the receptor protein. 

When the conditions of the nitromethane-aldose condensation reaction, with the exception that nitromethane was replaced by 2-nitro-ethanol, were applied to D-arabinose,61 the condensation reaction proceeded normally with rapid solution of the pentose followed by precipitation of the amorphous sodium aci-nitroalcohols. No attempt was made to isolate and separate the four isomeric nitroalcohols to be expected from the removal of sodium from these salts but, rather, they were sub-... 

The density of the melt is 1.89-1.94 gem-3. During electrolysis, along with sodium metal, small quantities of calcium ( 4 wt%) are deposited at the cathode. Calcium has a melting point (804°C) far higher than sodium and a low solubility in sodium (see Table 13) [302], Because of that at the cathode a solid alloy phase Na-Ca is accumulated and this blocks the circulation of the electrolyte in the electrolysis cell and the removal of sodium from the cell. Also this solid alloy sometimes causes short-circuiting in the electrolysis cell. Sodium obtained by electrolysis is cooled to 110-120°C and filtered for the removal of calcium. The effect of temperature on the solubility of calcium in sodium [302] is shown in Table 13. At 110°C the calcium content in sodium is reduced to <0.04%. 

The sodium-23 MASNMR results are consistent with the selective removal of sodium cations from the Y zeolite supercages by the partial cation exchange. This demonstrates that this technique can be used to monitor how cation distributions in Y zeolites change with various sample treatments. 

Sodium phenytoin, which mediates the removal of sodium ions from intracellular space during the refractory period of an action potential. 

All of the above solutions were stirred for 30 min with a magnetic stirrer. The pH of the solutions was adjusted to 6 or 8 with 6N NaOH immediately after addition of cysteamine. The reaction mixtures were extracted with 70 ml of dichloromethane or chloroform for 6 h using a liquid-liquid continuous extractor. The extracts were dried over anhydrous sodium sulfate for 12 h. After the removal of sodium sulfate, 0.5 mg of N-methylacetamide was added to each solution as an internal standard. The extracts were quantitatively analyzed for thiazolidine and 2-acetylthaizolidine by GC. 

The removal of water-soluble soils from textiles during dry cleaning is an application of secondary solubilization (9). The practical significance of this concept was illustrated by Fulton et al. (10). They were able to demonstrate that in dry cleaning, the removal of sodium... 

Aryldichloroarsines are methylated by dissolving in alcohol, adding sodium hydroxide and methyl iodide, then neutralising the mixture with hydrochloric acid and allowing it to stand for at least twenty-four hours. Removal of sodium chloride and alcohol yields crude arylalkyliodoarsine. 

British and German patents for its use for certain military purposes. The genesis of pcntryl from ethylene, through the intermediacy both of ethanolamine and of phcnylethanolamine, is indicated below. The preparation and properties of pcntryl have been studied extensively by LeRoy V, Clark at the U, S. Bureau of Mines. By the reaction of dinitrochlorobenzene in the presence of sodium hydroxide with ethanolamine in alcohol solution at 79-50 he procured dinitrophenylethanolamine in 70fo yield. The alcohol solution was filtered for the removal of sodium chloride, which was found to be mixed with a certain quantity of the by-product tetranitrodiphenylcthanolamine (lemon-yellow fine powder, m.p. 222 ) it was then concentrated to about one-third its volume, and deposited crystals of the product on cooling. This sulfunc acid and nitrated by... 

Removal of sodium by passing the eluate through a cation... 

The removal of sodium cations from the parent [Si,Al]MAG by treatment with hydrochloric acid results in the extraction of part of the framework aluminum as indicated by the low amount of ammonia (0.23 mmol/g) evolved in the high-temperature desorption step (Figure 3) from H-[Si,Al]MAG converted to the ammonium form by ion exchange or ammonia sorption prior to TPD. The formation of strong Lewis-acid sites (1462 cm )... 

There are two basically different approaches to achieving a major reduction of the volume of salt cake (1) removal of sodium, and (2) removal of radionuclides. Exploration of these two alternatives has been very limited so far such work as has been done is reviewed in the following sections. 

Removal of Sodium. Workers at the Battelle Pacific Northwest Laboratories (PNL) have recently published (21) results of a literature search and preliminary experiments performed to determine the feasibility of reducing salt cake volumes by the removal of sodium and purifying the sodium as metal for reuse or, at least, restricted storage. Methods considered by these scientists for removal of sodium from water solutions of salt cake included ... 

FIGURE 8.3 Vertical section of a Castner-Kellner rocking mercury cell, which demonstrates the principle of operation. The cell had provision for brine entry and removal of depleted brine from the left compartment, and for purified water entry and removal of sodium hydroxide from the right compartment. The eccentric revolved slowly to move the mercury on a regular basis between the two compartments. A cell divider extended close enough to the bottom of the cell to maintain a mercury seal, which prevented any mixture of the water phases of the two compartments. 

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