Extraction, purification

Solvent extraction—purification of wet-process phosphoric acid is based on preferential extraction of H PO by an organic solvent vs the cationic impurities present in the acid. Because selectivity of acid over anionic impurities is usually not sufficient, precipitation or evaporation steps are included in the purification process for removal. Cmde wet-process acid is typically concentrated and clarified prior to extraction to remove post-precipitated sludge and improve partition of the acid into the solvent. Concentration also partially eliminates fluoride by evaporation of HF and/or SiF. Chemical precipitation of sulfate (as Ba or Ca salts), fluorosiUcates (as Na salt), and arsenic (as sulfides) may also be used as a prepurification step preceding solvent extraction. 

Fig. 4. Schematic diagram of the solvent extraction purification of wet-process phosphoric acid.

By-Products. The biomass from the fungal fermentation process is called mycellium and can be used as a supplement for animal feed since it contains digestable nutrients (25,26). The lime-sulfuric purification and recovery process results in large quantities of calcium sulfate cake, which is usually disposed of into a landfill but can find limited use in making plaster, cement, waUboard, or as an agricultural soil conditioner. The Hquid extraction purification and recovery process has the advantage of Htde soHd by-products. 

Other industrial applications of electrolysis include extraction/purification of metals from ores, electroplating, and the manufacture of certain chemicals such as sodium hydroxide. In the latter, sodium chloride solution when electrolysed is converted to sodium hydroxide to produce chlorine at the anode and hydrogen at the cathode. Both of these gaseous by-products are collected for industrial use chlorine is used in the production of bleach and PVC hydrogen is used as a fuel, to saturate fats, and to make ammonia. 

Production of A1 metal involves two stages (a) the extraction, purification and dehydration of bauxite, and (b) the electrolysis of AI2O3 dissolved in molten cryolite Na3AlF6. Bauxite is now almost universally treated by the Bayer process this involves dissolution in aqueous NaOH, separation from insoluble impurities (red muds), partial precipitation of the trihydrate... 

Shimomura, O., and Johnson, F. H. (1967). Extraction, purification and properties of the bioluminescence system of the euphausiid shrimp Meganyctiphanes norvegica. Biochemistry 6 2293-2306. 

After extraction, an extract purification stage is generally reconunended. This is most often done by liquid-solid exchange using resins such as Sephadex, Amber-lite XAD-7, or Cjg mini-columns. ° All the polar compounds are first trapped on the resin, and then in succession the sugars, acids, and other polar compounds (excluding polyphenolic compounds), polyphenolic compounds (excluding anthocyanidins), and anthocyanidins are respectively eluted with acidified water (HCl 0.01% v/v), ethyl acetate, and acidified methanol (HCl 0.01% v/v). 

Updated infonnation regarding the extraction, purification, and functionalization of natural colors, with special focus on bioencapsulation procedures. The factors that specifically influence the stabihties of a whole range of natural colors, hydrophilic and lipophihc, for example, stabihty in the presence of low pH, fight, and heat, are considered along with solutions in given applications. 

Patent Data Related to Extraction, Purification, and Formulation of Carotenoid Pigments for Food and Feed Applications... 

Mort, A.J., Moerschbacher, B.M., Pierce, M.L., and Maness, N.O. (1991) Problems encountered during the extraction, purification, and chromatography of pectic fragments, and some solutions to them. CarbokydrMes. 215 219-227. 

Specifically for triazines in water, multi-residue methods incorporating SPE and LC/MS/MS will soon be available that are capable of measuring numerous parent compounds and all their relevant degradates (including the hydroxytriazines) in one analysis. Continued increases in liquid chromatography/atmospheric pressure ionization tandem mass spectrometry (LC/API-MS/MS) sensitivity will lead to methods requiring no aqueous sample preparation at all, and portions of water samples will be injected directly into the LC column. The use of SPE and GC or LC coupled with MS and MS/MS systems will also be applied routinely to the analysis of more complex sample matrices such as soil and crop and animal tissues. However, the analyte(s) must first be removed from the sample matrix, and additional research is needed to develop more efficient extraction procedures. Increased selectivity during extraction also simplifies the sample purification requirements prior to injection. Certainly, miniaturization of all aspects of the analysis (sample extraction, purification, and instrumentation) will continue, and some of this may involve SEE, subcritical and microwave extraction, sonication, others or even combinations of these techniques for the initial isolation of the analyte(s) from the bulk of the sample matrix. 

Shimomura O, Johnson FH, Saiga Y (1962) Extraction, purification and properties of aequorin, a bioluminescent protein from the luminous hydromedusan, Aequorea. J Cell Comp Physiol 59 223-239... 

Ahmed, H. 2005. Principles and Reactions of Protein Extraction, Purification and Characterization. CRC Press. 

Pure xylan is not employed in industry. but crude xylan or pentosans are of industrial importance. Xylan has been proposed as a textile size but is not employed as yet for this purpose.130 Perhaps the largest use of pentosans is in their conversion to furfural, which has many applications and serves as the source of other furan derivatives. At the present time, large quantities of furfural are used in the extractive purification of petroleum products, and recently a large plant has been constructed to convert furfural by a series of reactions to adipic acid and hexamethylene-diamine, basic ingredients in the synthesis of nylon. In commercial furfural manufacture, rough ground corn cobs are subjected to steam distillation in the presence of hydrochloric acid. As mentioned above, direct preferential hydrolysis of the pentosan in cobs or other pentosan-bearing products could be used for the commercial manufacture of D-xylose. 

Involvement of the processes of extraction, purification and concentration of the specimen under investigation,... 

A method for extraction, purification and preconcentration of dialkyldimethylammo-nium compounds and other detergents before determining their concentration in sewage water and activated sludge was described. It consists of a series of LLE and LC operations, the details of which are dependent of the original matrix, and end analysis was by HPLC-ELCD406. 

Analytical methods for determining disulfoton in environmental samples are reported in Table 6-2. The steps included in the methods are solvent extraction, purification and fractionation, and gas chromatographic analysis. Other analytical techniques, including capillary gas chromatography with mass selective detection (Stan 1989), high-performance liquid chromatography with either mass spectrometric (MS) or MS-MS detection (Betowski and Jones 1988), have been used to determine disulfoton in environmental samples. 

Hu Z, He M, Studies on mabinlin, a sweet protein from the seeds of Capparis masaikai levl. L. extraction, purification and certain characteristics, Acta Botan Yunnan, 5 207-212, 1983. 

Sample preparation is nsnally carried ont by means of two different approaches LLE or SPE, as recently reviewed by Servili et al. [344], LLE is carried ont by the partition of the nonpolar fraction (mainly TAGs) in n-aUcane solvent (nsnally -hexane) and of the polar fraction in a polar phase, usually methanol or methanol-water at different ratios [336,341,345-349]. SPE is carried out by means of C18 cartridges [343,350-354], Some authors performed LLE extract purification throngh a C18 cartridge [343],... 

Small sample preparation. For synthetic PFCs, this means synthesizing either a large amount of very small samples ( libraries ) obtained by combinatorial chemistry, or regular-size PFC samples for the use as drug candidates (respectively for their synthesis), for preparing impurities, metabolites, and other compounds. For natural PFCs it involves product extraction, purification, and characterization. 

In 1759 Count Vincenzo Masini (1689-1762) of Cesena, Italy, published a patriotic poem on sulfur, in which he described its extraction, purification, and uses. Signor Gino Testi has published extracts from this poem, with explanatory notes (74). In eloquent Italian verses Count Masini gave poetic expression to Giorgio Baglivi s belief that vegetables and animals exert an influence over the formation of the metals and the so-called semi-metals... 

Jared L. Anderson obtained his BS in 2000 at South Dakota State University and his PhD in analytical chemistry at Iowa State University in 2005. In August 2005, he joined the faculty at the University of Toledo (Ohio) as an assistant professor. In 2008, he was awarded a Faculty Early CAREER Award by the National Science Foundation. In the same year, he was awarded the Evangelos Theodosious Sigma Xi Young Faculty Research Award at the University of Toledo. His research interests include the use of ionic liquids in all aspects of separation science including analytical extractions, purification, and chromatography. 

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