Phosphorus precipitation

Fertilizer - [AMMONIUMCOMPOUNDS] (Vol2) -ammoniumsulfate [AMMONIUMCOMPOUNDS] (Vol2) -castor pomace as [CASTOR OIL] (Vol 5) -iron compounds m [IRON COMPOUNDS] (Vol 14) -from lignite and brown coal [LIGNITE AND BROWN COAL] (Vol 15) -lime fillers [LIME AND LIMESTONE] (Vol 15) -magnesiumnitrate [MAGNESIUM COMPOUNDS] (Vol 15) -molybdenum compounds as [MOLYBDENUMAND COMPOUNDS] (Vol 16) -phosphorus precipitator dust as [PHOSPHORUS] (Vol 18) -raw material for [SULFAMIC ACID AND SULF AMATES] (Vol 23) -sodium nitrate as [SODIUM COMPOUNDS - SODIUM NITRATE] (Vol 22) -vanadium as by-product [VANADIUM AND VANADIUM ALLOYS] (Vol 24)... 

Much clinical and experimental experience has been obtained about the manifestation of bone diseases, especially in renal patients. Many patients with Al-induced bone disease remain asymptomatic. There are two distinct forms of Al bone disease. The most severe form is osteomalacia, with recurrent fractures and resistance to vitamin D therapy. This disease is characterized by an increase of osteoid due to a mineralization defect induced by Al that is localized at a critical site in the bone, i.e., the osteoid calcification front [250]. The adynamic bone disease is another form of Al-related bone disease, characterized by a reduced bone turnover [97]. Al can have a direct negative effect on the bone by deposition at the mineralization front, causing a defective calcification. This is due to the influence of Al on calcium-phosphorus precipitation, crystal formation and crystal growth [251]. There might also be a toxic effect on the proliferation of osteoblasts and on mature osteoblasts with a time- and dose-dependent effect on osteoblast growth and function [143]. 

Phosphorus is removed in wastewater treatment plants by chemical means (e.g., phosphorus precipitation with iron or aluminum see Section 10.1.2) and by microbiological means known as biological phosphorous removal. The principal advantages of biological phosphorus removal include reduced chemical costs and a smaller sludge production as compared to chemical precipitation. It is based on the following facts ... 

Maurer, M., et al. (1999). Kinetics of biologically induced phosphorus precipitation in waste-water treatment. Water Res. 33, 2, 484-493. 

Phosphorus is known to be released from the sediments during anoxic conditions, as most of the time in the deep Gotland Basin (Hille et al., 2005). Otherwise, a change toward oxic conditions at the sediment surface causes phosphorus precipitation, mainly in the form of ironphosphates (Matthiesen et al., 2001), nearby or at the redox border that turns a few centimeter into the sediment because of bioturbation effects after recolonization of the seafloor. 

We use a combination of tangential cross-flow filtration and phosphorus precipitation to get organic phosphorus fractions that are sufficiently concentrated and relatively free of interfering dissolved organic matter. Cross-flow filtration is a popular method for fractionating natural dissolved organic matter into molecular weight frac-... 

In calcium-dominated wetlands, high concentrations of Ca can result in formation of complex calcium phosphate compounds of varying solubilities such as calcium phosphate, dicalcium phosphate, beta-tricalcium phosphate, octacalcium phosphate, and hydroxyapatite. Under these conditions, the phosphorus concentration in the soil pore water of calcareous soils is a function of Ca + activity. Solubility of these compounds decreases with an increase in Ca content. Insoluble beta-tricalcium phosphate is more likely to be found at a high pH. Thermodynamically, apatite is the most stable compound in soils. At relatively high phosphate concentrations, dicalcium phosphate or octacalcium phosphate may form and slowly transform to the more stable phase hydroxyapatite. These precipitation reactions can occur on the surfaces of calcite. The amount of exposed surface will determine the amount of phosphorus precipitated. In a Ca-saturated clay, calcium... 

The details of the method hy which H. Brand prepared phosphorus did not reach us hut the method of Kunkel (167(5) is known rather well. Fresh urine was evaporated forming a hlack precipitate which was heated at first carefully and then intensively with sand and coal. After removal of volatile and oily compounds, phosphorus precipitated on cold walls of the retort as a white deposit. The following chemical reactions were involved in the process ... 

The snowpack is aged during which time the BOD decreases further, and the pH increases while nutrients, such as phosphorus precipitate, do not redissolve when the snow melts. Organic particles also separate out forming a residue on melting. 

Trichloroethanoic acid, CCI3COOH. A crystalline solid which rapidly absorbs water vapour m.p. 58°C, b.p. 196-5" C. Manufactured by the action of chlorine on ethanoic acid at 160°C in the presence of red phosphorus, sulphur or iodine. It is decomposed into chloroform and carbon dioxide by boiling water. It is a much stronger acid than either the mono- or the dichloro-acids and has been used to extract alkaloids and ascorbic acid from plant and animal tissues. It is a precipitant for proteins and may be used to test for the presence of albumin in urine. The sodium salt is used as a selective weedkiller. 

These gases leave the furnace at about 600 K. pass through electrostatic precipitators to remove dust, and the phosphorus is then condensed out. 

Here again the simple formulation [Sb ] is used to represent all the cationic species present.) The hydrolysis is reversible and the precipitate dissolves in hydrochloric acid and the trichloride is reformed. This reaction is in sharp contrast to the reactions of phosphorus(III) chloride. 

Prolonged oxidation of any phosphorus compound, followed by standing in water, converts it to phosphate(V). This can then be detected by the formation of a yellow precipitate when heated with... 

Sulphonamides. Mix together 1 0 g. of the dry acid or 1 - 2 g. of the anhydrous salt with 2 5 g. of phosphorus pentachloride f and heat under a reflux condenser in an oil bath at 150° for 30 minutes. Cool the mixture, add 20 ml. of dry benzene, warm on a steam bath and stir the solid mass well to extract the sulphonyl chloride filter. Add the benzene solution slowly and with stirring to 10 ml. of concentrated ammonia solution. If the sulphonamide precipitates, separate it by filtration if no solid is obtained, evaporate the benzene on a steam bath. Wash the sulphonamide with a little cold water, and recrystallise from water, aqueous ethanol or ethanol to constant m.p. 

Place 125 ml. of glacial acetic acid, 7 -5 g. of purifled red phosphorus (Section II,50,d) and 2 5 g. of iodine in a 500 ml, round-bottomed flask fitted with a reflux condenser. Allow the mixture to stand for 15-20 minutes with occasional shaking until aU the iodine has reacted, then add 2 5 ml. of water and 50 g, of benzilic acid (Section IV,127). Boil the mixture under reflux for 3 hours, and filter the hot mixture at the pump through a sintered glass funnel to remove the excess of red phosphorus. Pour the hot filtrate into a cold, weU-stirred solution of 12 g. of sodium bisulphite in 500 ml, of water the latter should be acid to litmus, pro duced, if necessary, by passing sulphur dioxide through the solution. This procedure removes the excess of iodine and precipitates the diphenyl-acetic acid as a fine white or pale yellow powder. Filter the solid with suction and dry in the air upon filter paper. The yield is 45 g., m.p. 

Phosphorus. The presence of phosphorus may be indicated by a smell of phosphine during the sodium fusion. Treat 1 ml. of the fusion solution with 3 ml. of eoneentrated nitric acid and boil for one minute. Cool and add an equal volume of ammonium molybdate reagent. Warm the mixture to 40-50°, and allow to stand. If phosphorus is present, a yellow erystalline precipitate of ammonium phosphomolybdate wUl separate. 

Phosphorus is not oxidized or reduced biologically, but ortho-P may be formed from organic and poly-P. Ortho-P may be removed by chemical precipitation or biologically with sludges andwih be covered in a later section. 

The outer crust is composed of rust (hematite), precipitate, and settled particulate. Treatment chemicals may also deposit preferentially atop tubercles in response to associated corrosion. It is common to find several percent of zinc and phosphorus compounds in tubercles that grow in zinc- and phosphate-treated waters. Silicates also can be found in... 

The destiny of most biological material produced in lakes is the permanent sediment. The question is how often its components can be re-used in new biomass formation before it becomes eventually buried in the deep sediments. Interestingly, much of the flux of phosphorus is held in iron(lll) hydroxide matrices and its re-use depends upon reduction of the metal to the iron(ll) form. The released phosphate is indeed biologically available to the organisms which make contact with it, so the significance attributed to solution events is understandable. It is not clear, however, just how well this phosphorus is used, for it generally remains isolated from the production sites in surface waters. Moreover, subsequent oxidation of the iron causes re-precipitation of the iron(lll) hydroxide floes, simultaneously scavenging much of the free phosphate. Curiously, deep lakes show almost no tendency to recycle phosphorus, whereas shallow... 

As the most significant point sources of phosphorus are those from sewage treatment works (STW), control of phosphorus loading is most readily achieved either by precipitation of phosphorus with iron salts (iron(lll) sulfate or iron(lll) chloride) or by biological removal. The latter can only effectively be achieved in STWs using activated sludge and there have been many descriptions of this technique. ... 

A solution of 1.1 g of the cyanohydrin in 6 ml of pyridine is treated with 0.6 ml of phosphorus oxychloride and allowed to stand at room temperature overnight. The reaction mixture is quenched with ice and water and the resulting crystalline precipitate is collected, washed with water and dried to yield 1.05 g. Recrystallization from aqueous pyridine affords 0.88 g (83%) of 20-cyano-21-hydroxy-3,3-ethylenedioxypregna-5,17(20)-dien-l l-one acetate mp 197-200°. 

A typical modem phosphorus fumace (12 m diameter) can produce some 4 toniKs per hour and is rated at 60-70 MW (i.e. 140000A at SOOV). Three electrodes, each weighing 60 tonnes, lead in the current. The amounts of raw material required to make 1 tonne of white phosphorus depend on their purity but are typically 8 tonnes of phosphate rock. 2 tonnes of silica, 1.5 tonnes of coke, and 0.4 tonnes of electrode carbon. The phos rfKmis vapour is driven off from the top of the fumace together with the CO and some H2 it is passed through a hot electrostatic precipitator to remove dust and then condensed by water sprays at about 70 (P4 melts at 44.T). The byproduct CO is used for supplementary heating. 

Schwefel-natrium, -natron, n. sodium sulfide, -nickel, m. nickel sulfide, -niederschlag, m. precipitate of sulfur, precipitated sulfur, -ofen, m. sulfur burner, -oxyd, n. (any) sulfur oxide, -phosphor, m. (any) phosphorus sulfide, -probe, /. sulfur sample mercury sulfide, -quelle, /. sulfur spring, -rducherung, /. sulfur fumigation, -rubin, m. ruby sulfur, realgar, -salz, n. sulfur salt, thio salt, sulfo salt sulfate. 

A mixture of 10 g of the above piperazine carboxylate ester, 8 g of phosphorus pentoxide and 20 ml of phosphorus oxychloride is heated under reflux for about 1 day, diluted with 100 ml each of chloroform and benzene and quenched with 200 g of ice. The mixture is made basic with 10% sodium hydroxide. Theorganic layer is Isolated and extracted with 150 ml of dilute hydrochloric acid. The product is precipitated from the aqueous layer by addition of 10% sodium hydroxide, extracted with benzene and dried over potassium carbonate. Recrystallization from benzene-petroleum ether gives 2[Pg.77]

Meanwhile a stirred suspension of phosphorus pentachloride (14.99 g, 0.072 mol) in dry di-chloromethane (150 ml) was cooled to 0°C, and N,N-dimethylacetamide (27.5 ml) was added. The resulting solution was recooled to -10°C and 2-fur-2-yl)-2-methoxyiminoaceticacid (syn-isomer) (12.17 g, 0.072 mol) was added. The mixture was stirred at -10°C for 15 minutes and crushed ice (35 g) was added. The mixture was stirred at 0°C for 10 minutes, whereafter the lower dichloromethane phase was added over 10 minutes to the cephalosporin solution prepared above, cooled to -10°C so that the reaction temperature rose steadily to 0°C. The mixture was stirred at 0°C to 2°C for 1 hour, whereafter the cooling bath was removed and the reaction temperature allowed to rise to 20°C over 1 hour. The reaction mixture was then added slowly to 2 N hydrochloric acid (100 ml) diluted with cold water (1.15 C) at 5°C. The pH of the two-phase mixture was adjusted to below 2 with 2 N hydrochloric acid (10 ml), and the mixture was stirred and recooled to 5°C. The solid which precipitated was filtered, washed with dichloromethane (100 ml) and water (250 ml), and dried in vacuo at 40°C overnight to give the title compound (22.04 g, 86.6%). 

To a solution of 2.3 ml of phosphorus oxychloride in 50 ml of dry pyridine is added a solution of 2.2 grams of 3-N-bis((3-chloroethyl)carbamate of estradiol while stirring and at a temperature of about -10°C. The reaction mixture is allowed to stand at about 0°C for I /i hours, whereupon it is hydrolyzed by pouring it into ice-water. The main part of the pyridine is evaporated in vacuo, whereupon the residue is poured into 100 ml of cold 3.5 N hydrochloric acid with stirring. The precipitate thus obtained is isolated and washed with 0.1 N hydrochloric acid and water. 

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