CS270843B1 - Method of metallic iones e.g.th(iv),uo2 2+,la(iii),sr(ii),fe(iii),zn(ii),cd(ii),ni(ii),hg(ii),cu(ii) removal from aqueous solutions - Google Patents

Abstract

The method applies to the removal of metallic ions such as Th(IV), UO2<2+>, La(III), Sr(II), Fe(III), Zn(II), Cs(II), Ni(II), Hg(II), Pb(II), Cu(II) from aqueous solutions with the subsequent regeneration of used tenside that tensides of acids, type 2-/alkyl/-3-/2-hydroxyethyl/-3-azepentadium, with alkyl C6 to C20 act on the aqueous solutions of metals so that a molar ratio of tenside and metal is 1:1 to 3 in the extent of pH 1 to 9, while a separable precipitate of the metal complex with tenside arises either directly, or the pH is necessary for the creation of precipitate is achieved by adding mineral acids, such as sulphuric acid, nitric acid, hydrochloric acid (hydrogen chloride), and subsequently by adding the foresaid mineral acids in a concentration of 1 to 5 moles x dm<-3> to the isolated precipitate of the complex. Metallic ion is isolated in the form of a soluble inorganic salt under simultaneous precipitation of the original tenside. By the method described, 80 to 99.9 mass % of metal is removed from the aqueous solutions, and by a subsequent regeneration of tenside, 90 to 99 mass % of the original tenside is possible to obtain for repetitive use.

Description

The invention relates to a method for removing metal ions such as Th (IV), U ₂ ²⁺ , La (III),

Sr (II), Fe (III), Zn (II), Cd (II), Ni (II), Hg (II), Pb (II), Cu (II) from aqueous solutions.

Several methods are currently used to remove metal ions from aqueous solutions: extraction methods - Morrison GA, Freiser H .: Extraction Methods in Analytical Chemistry, SNTL, Prague (1962); Calligaro L., Mantovani A., Belluco U., Acampora M., Polyhedron 2, 1189 (1983); Malat, M .: Fresenius Z. Anal.Chem. 297, 417 (1979); Pakalns P .: Water Res. 15, 7 (1981); Chakravortty V., Oash KC _With Mohanty SR: Radiochim. Acta, 40, 89 (1986); Grimm R., Kolarik, Z .: 3. Inorg. Nucl. Chem. 36, 189 (1974); Schepper A .: Hydrometallurgy 4, 285 (1979). In classical extraction, the presence of surfactants affects the properties of the interfacial surface, which may negatively affect the extraction rate and extraction efficiency. ¹ Huttinger K.3. Those. 53, 574 (1981); Osseo-Asare K .: Why. Int. Solv. Extr. Conf. ISEC '83, Denver 278 (1983). When using a surfactant as part of the aqueous phase in extraction, the surfactant interferes with both phases to form emulsions, which negatively affects the whole process - Pakalns P .: Water Res. 15, 7 (1981). the ion flotation process involves the addition of an ionogenic surfactant to the counterion ion solution. By bubbling the system through air or nitrogen, the surfactant is adsorbed along with the separated component on the surface of the bubbles and is thus separated from the solution - Berg HW, Downey DM: Anal. Chim. Acta 120,237 (1980); 121, 239 (1980); 123, 1 (1981); Lieam-Fang-Wu, Shang-Da Huang:

3. Chines, Chem. Soc. 27, 165 (1980). Chelating sorbents were used to isolate the metal series: Kálalová E., Radová Z., lllbert K., Kálal 3., švec F .: Europ. Polym. 13, 299 (1977); Radová Z., Kálalová E., Kálal 3., Kukuškin 3u.N., Simanova S.A., Konovalov L.V., Then V.N .: AngeW. Dep. Chem., 81, 55 (1979); Kálalová E .: Chem. Avg. 31, 70 (1981). In many cases, the irreversibility of the sorption process, the use of high-concentration elution acids or column heating to enhance the metal desorption effect prevent Kanal G.A., Chow A .: Anal. Chim. Acta 78: 375 (1975). Ion exchange techniques are also used to obtain metals - Brapter K., Slonawska K .: Talanta 27, 745 (1980), Korkisch 3: Analytical Techniques in Evolutionary Chemistry, Pergamon Press 449 (1981). In multi-stage separation, the ion exchange process is combined with other preconcentration techniques - such as evaporation or extraction.

The above drawbacks are eliminated Ways to the removal of metal ions such as Th (IV), U0 ₂ ^2+, La (III), Sr (II), Fe (III), Zn (II), Cd (II), Ni (II) , Hg (II), Pb (II), Cu (II) from aqueous solutions followed by regeneration of the surfactant used, which is based on the treatment of the aqueous solution containing metal ions with acidic surfactants of the 2- (alkyl1) -3-) type Of 2-hydroxyethyl / -3-azapentanedioid with a C 1 -C ₂ alkyl in a surfactant to metal molar ratio of 1: 1 to 3 in the pH range of 1 to 9 to form a separable precipitate of the metal surfactant complex to which a mineral acid such as is sulfuric, nitric, hydrochloric acid at a concentration of 1 to 5 mol.dm &^lt; ^{-5 &gt};, the metal ion being isolated in the form of a soluble inorganic salt and the surfactant separated as a precipitate. By adding mineral acids such as sulfuric acid, nitric acid, hydrochloric acid, the pH of the aqueous solution containing the metal ions is adjusted.

The process according to the invention is demonstrated by examples.

Example 1

К water containing 10.2 ^"4 mol.dm" ⁵ La (III) was mixed with the equivalent amount of the sodium salt of 2- / hexadecyl / 3- / 2-hydroxyethyl / 3-azapentándiovej. In the solution thus prepared, a precipitate of the metal-surfactant complex forms directly at pH 4.2, which sedimentes within 5 to 20 minutes. After separation of the precipitate by filtration, the content of La is reduced (III) in a solution of 96% by weight .. From the precipitate may be isolated by addition of sulfuric C / SQ ^ ^ / = 2 mol.dm ^"5 recovered 99% by weight, the original surfactant to be removed as a precipitate from a solution of the simultaneously obtained metal salt and can be reused for further metal ion precipitation process.

and

Example 2

- 4 - 3

To water containing 3.5.10 mol.dm of Cd (II), add an amount of 2- (hexadecyl) -3- (2-hydroxyethyl) -3-azapentanedioic acid sodium salt such that the molar mass ratio of surfactant and metal is 1: 1 In the solutions thus prepared, a precipitate of metal with a surfactant forms directly in the pH range of more than 6.5, which settles within 1 to 10 minutes. After separation of the precipitate by filtration, the content of Cd (II) in the solution is reduced by a maximum of 98% by weight. a precipitate from a solution of the metal salt obtained simultaneously and can be reused for further metal ion precipitation process.

Example 3

In water containing 5.10 ⁴ mol.dm · · ⁵ Th (IV), add an amount of 2- (decyl) -3- (2-hydroxyethyl) 3-azapentanedioic acid sodium salt such that the molar mass ratio of surfactant to metal is 1: 1 In the pH range of 2.5, a precipitate of a complex of Th (IV) with a surfactant is formed, which settles over 1 to 5 minutes. After separation of the precipitate by filtration, the content of Th (IV) in the solution decreases by a maximum of 99% by weight. From the isolated precipitate, 99% by weight of the float surfactant can be recovered by adding sulfuric acid c / H 2 SO 4. a precipitate from a solution of the co-obtained metal salt and can be reused for another metal ion precipitation process.

Example 4

-4 - 3 +

An equivalent amount of sodium salt ^of 2- (decyl) -3- (2-hydroxyethyl) -3-azapentadioic acid is added to water containing 5.10 mol.dm of UO ₉ at pH 4.5, a precipitate of UO ₂ with a surfactant is formed. After separation of the precipitate by filtration, the metal content of the solution is reduced by 99.9% by weight. Example 5

An equivalent amount of 2- (decyl) -3- (2-hydroxyethyl) -3-azapentadioic acid sodium salt is added to water containing 2.5 x 10 6 mol.dm -1 Sr (II). In the solution thus prepared, a metal precipitate with a surfactant forms directly in the pH range 5.5. After separation of the precipitate by filtration, the metal content of the solution is reduced by 98% by weight.

Example 6

An equivalent amount of 2- (hexadecyl) -3- (2-hydroxyethyl) -3-azapentadioic acid sodium salt was added equivalently to water containing 2.5.times.10@-4 mol.dm} Fe (III). In the pH range 3, a precipitate of the Fe (III) complex with a surfactant is formed. After separation of the precipitate by filtration, the metal content of the solution is reduced by 97% by weight.

Example 7

К water containing 3.10 ^<4 mol.dm} Cu (II) was added the equivalent amount of the sodium salt of 2- / hexadecyl / 3- / 2-hydroxyethyl / 3-azapentándiovej. In the solution thus prepared, a precipitate of the metal-surfactant complex forms directly in the pH range 6. After separation of the precipitate by filtration, the Cu (II) content of the solution is reduced by 95% by weight.

Separation of metal ions using chelating surfactants of the 2- (alkyl) -3- (2-hydroxyethyl) -3-azapentadioic acid type with simple metal chelate isolation, high yield of the process in interconnection with the possibility of a high degree of regeneration of the parent components can be used as a simple and economical method for decontamination of waste water and contaminated surfaces, in relation to environmental protection and as a method of recovering metals from industrial waste.

Claims (2)

1. A method of removing metal ions such as Th (IV), U0 ₂ ² \ La (III), Sr (II), Fe (III), Zn (II), C (II), Ni (II), Hg (II ), Pb (II), Cu (II) from aqueous solutions followed by regeneration of the surfactant used, characterized in that the aqueous solution containing metal ions is treated with 2- (alkyl) -3- (2-hydroxyethyl) acid surfactants. 3-azapentándiových ^ 8 alkyl C ₆ to C _2Q in a molar ratio of surfactant to the metal of 1: 1 to 3 in the range of pH 1-9 to form a precipitate peelable metal complex with a surfactant, to which is added a mineral acid such as sulfuric acid, nitric acid , hydrochloric acid at a concentration of 1 to 5 mol.dm &lt; -1 &gt; wherein the metal ion is isolated in the form of a soluble inorganic salt and the tideide is collected as a precipitate. 2. The process according to claim 1, wherein the pH is adjusted by the addition of mineral acids such as sulfuric acid, hydrochloric acid and nitric acid.