Organophosphorous extractants

Two examples from the analysis of water samples illustrate how a separation and preconcentration can be accomplished simultaneously. In the gas chromatographic analysis for organophosphorous pesticides in environmental waters, the analytes in a 1000-mL sample may be separated from their aqueous matrix by a solid-phase extraction using 15 mb of ethyl acetate. After the extraction, the analytes are present in the ethyl acetate at a concentration that is 67 times greater than that in... 

Nickel and Cobalt. Often present with copper in sulfuric acid leach Hquors are nickel [7440-02-0] and cobalt [7440-48-4]. Extraction using an organophosphoric acid such as D2EHPA at a moderate (3 to 4) pH can readily take out the nickel and cobalt together, leaving the copper in the aqueous phase, but the cobalt—nickel separation is more difficult (274). In the case of chloride leach Hquors, separation of cobalt from nickel is inherently simpler because cobalt, unlike nickel, has a strong tendency to form anionic chloro-complexes. Thus cobalt can be separated by amine extractants, provided the chloride content of the aqueous phase is carefully controUed. A successhil example of this approach is the Falcon-bridge process developed in Norway (274). 

Zhu, T. A structure parameter characterizing the steric effect of organophosphorous acid extractants. International Solvent Extraction Conference, Cape Town, South Africa, Mar. 17-21, 2002, 203-207. 

Borburgh HJ, Hammers WE. 1992. Extraction of organophosphorous pesticides from water samples on Bakerbond SPE octadecyl cartridges at the ng/L level. Toxicol Environ Chem 35(1 ) 79-86. 

The chemistry of the extraction of UO + by mixtures of organophosphoric acids and neutral organophosphorus compounds has been the subject of many studies, and the available information has been widely discussed.75 118 127 131 134 There is no general agreement on the mechanism of the synergistic effect, although an addition process such as... 

It has been shown that the extraction of thorium(IV) by organophosphoric adds involves the mechanisms... 

Kumar, R Pal, A. Saxena, M.K. Ramakumar, K.L. Supercritical fluid extraction of thorium from tissue paper matrix employing organophosphorous reagents, Radiochim. Acta 95 (2007) 701-708. 

Smirnov, I.V. 2007. Anomalous effects in extraction of lanthanides and actinides with bidentate neutral organophosphorous extractants. Role of proton hydrate solvates. Radiochemistry 47(1) 44—54. 

A. S. Kertes. The chemistry of the formation and elimination of a third phase in organophosphorous and amine extraction systems. In Solvent Extraction Chemistry of Metals. H. A. C. McKay, T. V. Healy, I. L. Jenkins, and A. Naylor, Macmillan, London, 1965. pp. 377-399. 

Accelerated solvent extraction is a new technique for the extraction of a range of organic pollutants from soils and related material. The technique is based on the use of a solvent or combination of solvents to extract organic pollutants at elevated pressure and temperature from a solid matrix. The range of organic pollutants for which the technique is proposed includes semi volatile compounds, organochlorine pesticides, organophosphorous pesticides, chlorinated herbicides, polychlorinated biphenyls and polycyclic aromatic hydrocarbons [66-69]. 

Kolarik Z. Critical evaluation of some equilibrium constants involving acidic organophosphorous extractants. Pure Appl Chem 1982 54 2593-2674. 

Kolarik Z, Grimm R. Acidic organophosphorous extractants XXIV the polymerization behavior of Cu(II) Cd(II), Zn(II) and Co(II) complexes of D2EHPA in fully loaded organic phases. J Inorg Nucl Chem 1976 38 1721-1727. 

Table 14. Equilibria and their stoichiometric constants (K) involved in the synergistic extraction of Pu(IV) from nitric acid medium by solutions of HTTA and some neutral organophosphorous donors (B)24,25). Aqueous medium = 1.0M nitric acid diluent - benzene Temp. — 25°C... 

Z. Kolarik, Critical Evaluation of some Equilibrium Constants Involving Acidic Organophosphorous Extractants. Pure Appl. Chem.,... 

Kislik V and Eyal A. Mechanisms of titanium(IV) and some other transition metals extraction by organophosphoric acids. In Logsdail DH and Slater Ml Eds. Proceedings of ISEC 93, London, July 1993. Elsevier Applied Science for SCI 1993 3 1353-1361. 

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