Sulfate precipitation

The gaseous ammonia is passed through electrostatic precipitators for particulate removal and mixed with the cooled gas stream. The combined stream flows to the ammonia absorber where the ammonia is recovered by reaction with a dilute solution of sulfuric acid to form ammonium sulfate. Ammonium sulfate precipitates as small crystals after the solution becomes saturated and is withdrawn as a slurry. The slurry is further processed in centrifuge faciHties for recovery. Crystal size can be increased by employing one of two processes (99), either low differential controUed crystallization or mechanical size enlargement by continuous compacting and granulation. 

Barium sulfate [7727-43-7] BaSO, occurs as colorless rhombic crystals, mp 1580 °C (dec) sp gr 4.50 solubihty 0.000285 g/100 g H2O at 30°C and 0.00118 at 100°C. It is soluble in concentrated sulfuric acid, forming an acid sulfate dilution with water reprecipitates barium sulfate. Precipitated BaSO is known as blanc fixe, prepared from the reaction of aqueous solutions of barium sulfide and sodium sulfate. 

The white cesium fluoroxy sulfate precipitates from the reaction medium and may be kept for several months in the cold (0 to -15 °C) Metal surfaces can cause detonation of the reagent. The reaction scope of cesium fluoroxysulfate seems narrower than that of acetyl hypofluorite because of its limited solubility in organic solvents Cesium fluoroxysulfate has not been prepared with a fluorine-18 label. 

About 250 ml of a reaction mixture obtained by the electrolytic reduction of nitrobenzene in sulfuric acid solution and containing about 23 grams of p-aminophenol by assay is neutralized while at a temperature of 60° to 65°C, to a pH of 4.5 with calcium carbonate. The calcium sulfate precipitate which forms is filtered off, the precipitate washed with hot water at about 65°C and the filtrate and wash water then combined. The solution is then extracted twice with 25 ml portions of benzene and the aqueous phase is treated with 0.5 part by weight, for each part of p-aminophenol present, of activated carbon and the latter filtered off. The activated carbon is regenerated by treatment with hot dilute caustic followed by a hot dilute acid wash, and reused a minimum of three times. 

A portion (950 ml) of the rich eluate was adjusted to pH 6.0 by the addition of sulfuric acid. Ultrawet K (7.0 g) in 70 ml water was added slowly to the neutralized eluate to precipitate kanamycin B dodecylbenzenesulfonate which was collected by filtration after adding filter-aid (Dicalite). The cake was washed with water and extracted with 100 ml methanol. After filtering and washing with methanol, sulfuric acid was added to the filtrate until no more kanamycin B sulfate precipitated. After addition of an equal volume of acetone to provide more complete precipitation, the kanamycin B sulfate was collected by filtration, washed with methanol and dried in vacuo at 50°C. 

To one liter of 0.001 M H2SO is added 0.002 mole of solid Pb(N03)2. As the lead nitrate dissolves, will lead sulfate precipitate ... 

The purple protein is reddish in solutions and purple in the ammonium sulfate precipitate. The molecular weight is 39,000 by the sedimentation equilibrium method. The purple protein is brightly red-fluorescent, but the fluorescence characteristics cannot be related to the luminescence of Latia (Fig. 6.1.5 Shimomura and Johnson, 1968c). 

Step 3. The photoprotein fractions are combined and the NaCl concentration of the solution is reduced to 50 mM by gel filtration through a column of Sephadex G-25. Then, the solution is poured onto a column of DEAE cellulose. The photoprotein adsorbed on the column is eluted by a linear increase of NaCl concentration from 50 mM to 0.4 M in the same pH 6.7 buffer. Active fractions are combined and concentrated by ammonium sulfate precipitation. 

Step 4. A repetition of gel filtration on a smaller column of Ultragel AcA 54, followed by the concentration of the eluted photoprotein by ammonium sulfate precipitation. 

Ammonium Sulfate Precipitation. The extract was made up to 40% saturation with the slow addition, with stirring, of ammonium sulfate at 4°C. After several hours, the precipitate was removed by centrifugation at 30,000 g for 30 min and the supernatant retained. It was brought to 100% saturation in similar conditions, the precipitate was collected by centrifugation, dissolved in the minimum of distilled water, dialyzed against water and then against 1% glycine, and lyophilized. 

Figure 2. Gel filtration. The dry residue obtained after ammonium sulfate precipitation was redissolved in 50 mM phosphate buffer, pH 7.4 0.15 M NaCl 0.013 % sodium azide, which was loaded on a Superdex 75HR1030 column equilibrated with the same buffer. Elution was downward flow (0.15 ml/min) and 0.25 ml fractions were collected. The fractions were assayed for protein content (— ) and PNL activity (- - ).

Figure 5 shows the pattern of lyase isoenzymes along the purification process at first, three bands with lyase activity (pis 9.20, 9.00 and 8.65) were detected in the ammonium sulfate precipitate (B 1) in the peak eluted from the Superdex 75HR1030 column, only one band with lyase activity was detected, that correspond to the PNL with pi 9.20 (B 2), but more proteins were detected by silver staining (A 2). 

In recent years, many hydrothermal solution venting and sulfide-sulfate precipitations have been discovered on the seafloor of back-arc basins and island arcs (e.g., Ishibashi and Urabe, 1995) (section 2.3). Therefore, it is widely accepted that the most Kuroko deposits have formed at back-arc basin, related to the rapid opening of the Japan Sea (Horikoshi, 1990). 

Nielsen, A.E. (1957) Nucleation in barium sulfate precipitation. Acta Chem. Scand., 11, 1512-1515. 

Suito, E. and Takiyama, K. (1954) Formation and aging of precipitates. I. Electron microscopic studies of the formation of barium sulfate precipitate. Bull. Chem. Soc. Japan, 27, 121-123. 

Copper sulfate can be described as a by-product of copper refining that is obtained by crystallization of the weak liquor. The copper sulfate precipitate formed is centrifuged, dried, screened, and finally packaged in bags and drum. However, it is produced in some chemical industries by reacting copper shot with sulfuric acid, air, and water. It is widely used as an insecticide, additive nutrients (for soils that are deficient in copper), copper electroplating, wood preservation, and in petroleum refining. 

Measurements of 226radium are simpler than those for 228radium and are more precise. These measurements are generally made by concentrating the radium from up to a few litres via barium sulfate precipitation followed by thick source a counting or by 222radon extraction following dissolution of barium sulfate [21]. 

Figure 11.9 Production of rhGH in . coli (as an intracellular protein). Subsequent to fermentation, the cells are collected by centrifugation or filtration. After homogenization, nucleic acids and some membrane constituents are precipitated by the addition of polyethyleneimine. Ammonium sulfate precipitation of the supernatant concentrates the crude rhGH preparation. Chromatographic purification follows, as illustrated...

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