Precipitants solubility

Hydrochloric acid or any soluble chloride gives a white precipitate, soluble in ammonia. 

Sodium alumiaate is an effective precipitant for soluble phosphate ia sewage and is especially useful ia wastewater having low alkaliaity (20,21). Sodium alumiaate hydrolyzes ia water to Al(OH)2 and Al" which precipitate soluble phosphate as aluminum phosphate [7784-30-7], AlPO. Sodium alumiaate has also been described as an effective aid for the removal of fluorides from some iadustrial waste waters (22). Combiaations of sodium alumiaate and other chemicals are being used to improve the detackification of paint particles ia water from spray-painting operations (23). 

M. M. Jordan, K. S. Sorbie, P. Chen, P. Armitage, P. Hammond, and K. Taylor. The design of polymer and phosphonate scale inhibitor precipitation treatments and the importance of precipitate solubility in extending squeeze lifetime. In Proceedings Volume, pages 641-651. SPE Oilfield Chem Int Symp (Houston, TX, 2/18-2/21), 1997. 

Metal hydroxides (e.g., Fe, Mn, Al) can also be a problem (Rauten-bach and Albrecht, Membrane Processes, Wiley, New York, 1989). A chemical analysis of the feed solution composition along with consideration of solubility products allows one to determine the significance of precipitation. Solubility products can be affected by temperature, pH, and ionic strength. Seasonal temperature variations must be considered. Concentrations of silica need to be < 120 mg/L in the feed. 

The principal abiotic processes affecting americium in water is the precipitation and complex formation. In natural waters, americium solubility is limited by the formation of hydroxyl-carbonate (AmOHC03) precipitates. Solubility is unaffected by redox condition. Increased solubility at higher temperatures may be relevant in the environment of radionuclide repositories. In environmental waters, americium occurs in the +3 oxidation state oxidation-reduction reactions are not significant (Toran 1994). 

Observations A white precipitate (soluble in dilute ammonia) indicates a chloroalkane. A cream precipitate (insoluble in dilute ammonia but soluble in concentrated ammonia) indicates a bromoalkane. A yellow precipitate (insoluble in both dilute and concentrated ammonia) indicates an iodoalkane. 

The effect of pH changes on precipitate solubilities merits special consideration. The dependence of solubility on pH may derive from the common ion effect where OH- or H30+ ions are generated by the dissolution of the precipitate, e.g. 

Insoluble Fe(OH)2 is formed which precipitates soluble and insoluble inorganic and organic pollutants from the solution. The mechanism for removing contaminants from wastewater is not yet fully understood [312,317-319]. The process has proved itself to be highly effective in the removal of the color and heavy metals. Disadvantage The iron sludge must be dumped (landfills are scarce) or dried, pelleted and sintered for disposal in iron mills (very costly). 

Precipitation Soluble Qualitative or quantitative Double diffusion Single radial diffusion... 

Colorless crystals faint vinegar odor melts at about 178°C decomposes at higher temperature or when heated rapidly soluble in water the solution decomposes on standing producing a yellow precipitate soluble in alcohol. 

The pentahydrate Rh203 5H20 is a yellow precipitate soluble in acids partially dissolves in hot water ignites to form anhydrous oxide. 

Amorphous forms exhibit two colors, occurring as a red powder of density 4.26g/cm3 that has a hexagonal crystal structure and a black vitreous solid of density 4.28g/cm3. The red amorphous selenium converts to the black form on standing. Amorphous selenium melts at 60 to 80°C insoluble in water reacts with water at 50°C when freshly precipitated soluble in sulfuric acid, benzene and carbon disulfide. 

Heavy white crystals orthorhombic structure density 4.15 g/cm decomposes at 378°C to Sn02 and SO2 soluble in water, reacting to form a basic sulfate that precipitates soluble in dilute sulfuric acid. 

C. W. Scheele (1773) noted that a damp mixture of common salt and calcium hydroxide effloresces after some weeks exposure to air, the efflorescent salt is sodium carbonate. It is probable that calcium bicarbonate is formed, which precipitates soluble sodium bicarbonate, and this explains the formation of the efflorescence of soda from salty soils. The observation made by C. W. Scheele... 

Substrate products can be classified as either soluble or precipitating. Soluble peroxidase substrates include o-phenylenediamine, which is converted into a yellow product 2,2 -azino-(3-ethyl)-benzothiazoline-sulfonic acid, which is converted into a green product and tetramethylbenzidine, which is converted into a blue product. Precipitating substrates for peroxidase include 4-chloronaphthol, which yields a blue precipitate and aminoethylcarbizole, which forms a red precipitate. Alkaline phosphatase is most frequently used with p-nitrophenyl phosphate to give a yellow-orange soluble product, or with 5-bromo-4-chloro-3-indo-lyl-phosphate p-toluidine salt to yield an insoluble blue product. 

Dihydroxylamidosulphonic Acid, N(OH)2SQ3H.—A basic salt of this acid having the composition N (OH) (OK )SO 3K has been obtained as the first product of the interaction of sulphur dioxide with a concentrated alkaline solution of potassium nitrite.3 The salt is alkaline in solution and with barium chloride yields a white precipitate, soluble in acids. Sulphuric acid liberates nitrous oxide from it. 

The most important chemical parameter affecting the deposition and subsequent mobility of radioactive aerosols, such as the nuclides 90Sr and 137Cs examined in this study, is their solubility in rainwater. If these aerosols are dissolved in precipitation, the main factor in their transport is the movement of the rainwater, not the transport of insoluble aerosol particles. Huff and Kruger (2) examined the solubility products of strontium and chemically similar compounds which may carry trace amounts of 90Sr, and they estimated that strontium should be soluble in precipitation. Solubility tables also indicate that cesium compounds likely to exist in precipitation should be soluble. It was noted that the possibility did exist that some of the fission product "Sr and 137Cs might be bound within the structure of insoluble natural aerosols or nuclear weapon debris. 

Zinc. — Dissolve 1 gm. of manganous chloride and 1 gm. of sodium acetate in 10 cc. of water, and add a few drops of acetic acid and hydrogen sulphide water. No white precipitate soluble in hydrochloric acid should form. 

Uranyl Thioarsenate is also obtained by double decomposition. It is formed as a dirty yellow precipitate, soluble in excess of the alkali orthothioarsenate.5... 

FeClg, bluish-black precipitate, soluble in HC1, but reprecipitated by ammonia. 

NaOH—Base precipitated, soluble in excess of NH4OH. 

Aluminium (Al3+) White precipitate, soluble in excess giving a colourless solution... 

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