Sorbent-based silicate antimony removal of metal ions

 

Proposed material containing doped silicate antimony, as a sorbent for removal of metal ions, for example ions of radioactive metals from acidic liquid medium. Metal ions can be selectively removed from a mixture with other ions such as ions of Na, K, mg, and CA. Method for obtaining material on the basis of antimony silicate, used for removal of metal ions doped by one or more elements selected from the group consisting of tungsten, niobium and tantalum. The doped material is particularly effective as a sorbent for removal of metal ions, in particular strontium, from the liquid environment. 4 C. and 6 C.p. f-crystals, 20 ill., 5 table.

The present invention relates to the removal of metal ions from phase solution. For example, it can be used to remove radionuclides from solution, but it should be understood that this invention is no way limited to radionuclides.

In the nuclear industry get large amounts of waste water containing radionuclides and other contaminants metal compounds. It is desirable to remove such waste water with the minimum volume to the maximum capacity of treatment facilities. Usually the activation, and heavy metals. To remove these products were used methods such as flocculation or ion exchange, which usually lead to success. However, some radionuclides are more difficult to remove than others. For example, ions of strontium difficult to remove by known methods of ion exchange, if they are present in the acidic environment. In addition, other ions present in solution, for example CA2+MD2+, PA+To+can interfere with the absorption of strontium. Available in industry materials for removal of Sr include clinoptilolite (a zeolite mineral), sodium titanates (company "Allied Signal", USA), titanosilicate CST (firm RBI, USA) and material based on titanium oxide SrTreat (firm "Selion OY, Finland), which work more effectively in a neutral or alkaline medium.

According to the first aspect of the present invention is proposed to use a material containing antimony silicate, as a sorbent for removal of metal ions from the acidic liquid medium.

Metal ions may be ions of radioactive metals.

Ions of radioactive metals may include ions of Sr, Cs, Co, Pu, or Am.

Ions of radioactive metals can be removed from the acidic liquid medium, which contains background ions, such as low can be selectively removed from the acidic liquid medium, which contain background ions, such as ions of Na, K, mg, and CA, and the background ions remain in the liquid medium.

According to the second aspect of the present invention, a method for obtaining material containing antimony silicate, and this method includes a reaction with each other in liquid silicon-containing compounds and compounds containing antimony, in the conditions of polymerization, characterized in that the molar ratio Si:Sb is less than about 20, and the reaction product is dried at a temperature of from 40 to 800oFor the formation of this material.

Preferably the reaction products are dried at a temperature of from 40 to 300oC. More preferably, the product is dried at a temperature of from 40 to 100oC.

According to a third aspect of the present invention, a method of extraction of metal ions from aqueous solution, involving the interaction of the aqueous solution with a material containing antimony silicate obtained according to the method of the second aspect of the present invention.

Ions can be radioactive ions. Ions may be ions of strontium. The aqueous solution can have a pH of less than 7.

The inventors have found that a material containing antimony silicate, is vsokoaffinny the C aqueous solutions.

This material is effective for the selective removal of ions of Sr, Co, Pu and Am from a solution containing background metal ions, such as Na, K, mg, and CA, and the background ions remain in the solution.

It was found that the antimony silicate, in particular, is effective for removal of radioactive ions. Radioactive ions can include one or more ions of metals such as Sr, Cs, Co, or Pu. You can also remove toxic ions of heavy metals.

It was found that this material has an efficiency comparable with that available in the industry ion exchange materials for the removal of many ions, and found that it is much more effective than commercially available materials for the removal of certain ions. This material is more effective for removal of ions of Sr, Co, Pu, and Am, than, for example, many commonly used ion exchangers. This material is very effective for removal of Sr ions from aqueous solution.

It was found that this material is particularly good for removing Sr ions from the acidic environment. In contrast, the known ion exchangers are ineffective in the removal of metal ions, in particular Sr from acidic aqueous environment.

The value Kdfor several nuclides in different "model" environments DD>m (I), where aidenotes the initial concentration of the cation, And the cation concentration after contact with the ion exchanger, V is the volume of solution and m is the mass of ion exchange material. The value of Kdis used to assess the technological capacity of the material. Kdis a measure of the isotope distribution between the solid and liquid phases.

This material is much more efficient for the absorption of Sr than, for example, commercially available materials, such as CST and clinoptilolite, see Fig.2 and tables 1, 2 and 3.

This material is also more efficient for the absorption of Sr than industrial materials, in the presence of other cations, such as Na+, see Fig. 7.

This material may be amorphous or crystalline, but it is preferable that he was crystalline.

Preferably, the x-ray crystal material showed characteristics of crystalline silicate antimony.

As for the method of producing silicate antimony, compounds containing silicon and antimony, can be compounds previously used for the synthesis of antimony silicates, as for example in the work of J. Solid State Chem. , 99, 173 (1992). For example, the silicon-containing compound may be Si(OC2H5)46or SbCl5. The compound containing antimony, may be dissolved in water or other suitable solvent. Preferably the compound containing antimony, contains Sb(V), instead of Sb(III).

The molar ratio of Si: Sb is less than about 20. Preferably the molar ratio of Si:Sb less than 5. More preferably the ratio of Si:Sb is in the range from 3:1 to 1:3. Most preferably the ratio of Si:Sb is from 1:1 to 1:2.

The reaction product can be dried within a certain period of time, for example several days. The reaction product can be dried during the night. The reaction product is dried at temperatures from slightly above room temperature to about 800oC. More specifically, the drying temperature ranges from 40 to 800oC.

Preferably the drying temperature is from 40 to 300oC. More preferably, the drying temperature is from 40 to 100oC. In a typical case, the reaction product can be dried overnight at a temperature of from about 40 to about 70oC.

In Fig. 8 shows the distribution coefficient Kd

The conditions required for polymerization can be achieved by adding a suitable catalyst of polymerization, such as, for example, acid. Acid can be a HNO3, HCl, or H2SO4. The acid can be added to the compound containing antimony, before add silicon-containing compound, or after that.

The reaction product can be filtered and/or washed in one or several stages before or during drying.

According to a fourth aspect of the present invention proposed a material containing silicate of antimony doped by one or more members selected from the group consisting of tungsten, niobium and tantalum, which will be called here alloying elements. The material according to the fourth aspect will be called alloyed material.

According to the fifth aspect of the present invention it is proposed to use a material containing antimony silicate, Le is the firmness of the sorbent for the removal of metal ions from a liquid medium.

According to the sixth aspect of the present invention, a method of extracting metal ions from an aqueous solution that includes the interaction of the aqueous solution with alloyed material according to a fourth aspect of the present invention.

The doped material may be doped with only one element from the group consisting of tungsten, niobium and tantalum. The doped material may be doped with two or more elements from the group consisting of tungsten, niobium and tantalum.

The tungsten and/or niobium are preferred alloying additives.

The molar ratio of Sb : Si : alloying element may be in the range from about 1:1:0.005-approximately 1:1:2 for the case when the ratio of Sb : Si is approximately 1:1. In General, best results are obtained when the relative content of the alloying element, i.e., the ratio of Sb : Si : alloying element is from about 1:1:0.01 to about 1:1:0,5. However, the optimum relative content of the alloying element may not always be in the above range, since other factors such as the ratio of Si: Sb, type of reagents used for synthesis, drying time and temperature can affect the optimum alloying the n to be removed from the solution.

Preferably the concentration of the alloying element in the material, expressed in wt. % must be in the range from about 0.5 to about 30.0 wt.%. The exact optimal concentration of the alloying element will depend, inter alia, from which ion must be removed from the solution. Some optimal concentration of tungsten used as alloying element for different ions, shown in Fig.13.

The doped material may be crystalline or amorphous in structure. The crystal structure is preferred. The x-ray crystal structure preferably should be substantially similar to the x-ray crystalline silicate antimony.

Also it was found that the doping antimony silicate, one or more elements selected from the group consisting of tungsten, niobium and tantalum, changes the selectivity for different ions. Thus, the selective doping of the above-mentioned alloying elements can be adjusted in such a way as to make the antimony silicate is more selective towards specific metal ions. For example, it was found that alloying with tungsten may lead to more selective behaviour is teaching material, containing silicate of antimony doped by one or more elements selected from the group consisting of tungsten, niobium and tantalum, and this method involves the reaction with each other in liquid silicon-containing compounds, compounds containing antimony and compounds containing one or more elements, the conditions of polymerization.

The method according to the seventh aspect of the invention includes the features (mandatory and secondary) of the method according to the second aspect of the invention to obtain antimony silicate, in cases where they are applicable.

Fourth, fifth, sixth and seventh aspects of the present invention include signs (mandatory and secondary) first, second and third aspects in cases where they are applicable.

Next, specific embodiments of the present invention will be described using the following examples. These examples are only illustrative, and in no way limit this invention.

Examples (1) Receiving basic compounds antimony Silicates received the following two methods.

Method And 5,26 g Sb(OH)6was dissolved in 360 ml of distilled H2O and this solution is then added with stirring to 4,17 g TEOS, razii and the mixture was stirred 1 hour at 77oC. the Obtained product was washed with distilled water and dried. The dried product was then heated for formation of the desired material. Method x-ray diffraction analysis, it was found that these materials are amorphous (see Fig.1). Table 1 shows the values of Kdfor various ions for sample, which was heated to 450oC.

Method In SbCl5mixed with silicate, sodium PA2Si3O7in the presence of 4M Hcl, while maintaining the pH value of about 1. This mixture was formed into a jelly-like product after keeping at 60oWith during the night. This product was filtered, washed and dried; the radiograph showed that the material is crystalline.

The results described below were obtained using the material synthesized by the method As described above.

(2) the Effect of pH and ions present other metals.

In Fig. 2 and 3 shows how the value of Kdremoval85Sr depending on the pH in 0.1 M NaNO3for antimony silicate obtained at 450oSince, as indicated above, commercial samples CST and clinoptilolite and manufactured material SrTreat. The value Kdfor antimony silicate are almost constant in intervie CST and clinoptilolite.

Fig.4 shows how the value of Kdaffected by the presence of calcium ions.

In Fig.5 shows how the value of thedaffected by the presence of ions MD2+.

In Fig.6 shows how the value of thedaffected by the presence of ions To+.

In Fig.7 shows how the value of thedaffected by the presence of ions of Na+.

(3) the Effect of temperature synthesis of Various samples of antimony silicate were then obtained by heating the product to different temperatures. The samples were obtained by heating to 100, 200, 300, 450, 600 and 800oC. In Fig.8 and 9 are shown asdfor85Sr and57Co varies with temperature synthesis. A weak maximum is visible at about 300oC. Separate results are shown for the case when in the course of the synthesis was added to the acid before silicate (see below).

(4) the Effect of adding acid before adding the silicate Samples were obtained at different temperatures of synthesis, as described above, except that before the addition of TEOS was added a certain amount of HNO3to accelerate the dissolution Sb(OH)6. A comparison of values Fordwhen preliminary addition and without adding NGO3it is shown in Fig.8 and 9. The material obtained is about.

(5) Effect relationships Sb:Si was also held synthesis, which varied the ratio of Sb:Si. Used relations Sb: Si equal to 1:1, 2:1, 3:1, 1:2 and 1:3. In addition, synthesis was performed without silicate to get armaou acid. The synthesis temperature was approximately 100 and 300oC. the Value Kdfor85Sr in 0.1 M HNO3it is shown in Fig.10.

Arimana acid and the material obtained when the ratio of Sb:Si=l:2, showed the best performance. When the number of85Sb values Todfor85Sr tendency to decrease. It was found that the ratio of Sb:Si, giving best performance for removal of Sr, is from 1:1 to 2: 1.

(6) Receiving silicate Surma, doped tungsten
Method And
Na2WO42H2O was mixed with KSb(OH)6and TEOS at pH corresponding to the acidic environment, when the molar relationship Sb:Si:W 1:1:0,5, 1:1:1, 1:1:2 and 1:1:. 0,1. The mixture was kept in an oven at 77oWith during the night and the obtained gel-like product was filtered and dried at room temperature. Thus obtained materials from x-ray analysis were amorphous.

Method In
Crystalline material doped with tungsten, the s simultaneously with a solution of 3.3 g of Na2WO42H2O in 100 ml of water. Quickly added another 200 ml of water. Used several different ratios of Sb: Si: W and varied the time of heating at 77oC. Radiographs were typical for crystalline silicate antimony.

(7) the Value Kdfor antimony silicates, doped tungsten
Table 4 shows the values of Kdfor removal of Cs, Sr and Co in 0.1 M NGO3using antimony silicates, doped tungsten, obtained by both methods a and b described above.

For Sr values Fordshow a slight improvement compared to undoped silicate antimony, except for very low concentrations of W, for example Sb:Si:W=1:1:0,1.

On the other hand, removal of Cs values Fordhave a tendency to increase with increasing concentration of W with a subsequent decrease at higher concentrations, W. Doped tungsten materials are generally more selective in relation to the Cs than the undoped material.

In Fig.11a.b.c shows how to change the value Kddepending on the pH in 0.1 M NaNo3.

In Fig.12 shows how the value of Kdfor. Sr varies depending on the concentration of CA(NO3)2.

the lines of tungsten in the material.

(8) antimony Silicates, doped niobium
To obtain a material with the ratio of Sb:Si:Nb=1:1:0.48 solution of sodium silicate (27% SiO2, 14% Paon) was diluted to 80 ml with distilled water. This solution was rapidly added to a stirred solution of 1.22 g SbCl5and of 0.53 g Nbl3in 4M Hcl (20 ml). Formed as a result of this clear, colorless solution was left overnight at room temperature, at 348 To or at 473 K. the Obtained products were isolated by centrifugation, washed with distilled water and dried in air at 348 K. Then received other samples with different relations Sb:Si:Nb.

(9) the Values of Kdfor antimony silicates doped with niobium
Table 5 shows the values of Kdfor CS, Sr and Co in 0.1 M NGO3for doped with niobium antimony silicates obtained at different molar ratios and temperatures.

For ions Cs maximum value To adobserved when the ratio of Nb:Sb in the range from 0.01 to 0.05 and at a temperature synthesis 298 K. However, when using the synthesis temperature 473 K max Kdobserved near relations Nb:Sb approximately 1:1.

For ions Sr maximum value To adusually observed at low concentrations of Nb.

2. The material under item 1, in which one or more elements present in the material at a concentration ranging from about 0.5 to about 30 wt.%.

3. The material under item 1 or 2, wherein the material has a crystalline structure, as shown by x-ray structure analysis of the material.

4. The material on p. 3, in which the crystal structure is essentially the same as the crystalline silicate antimony.

5. A method of obtaining a material according to any one of paragraphs.1-4, including interaction in liquid silicon-containing compounds, compounds containing antimony and compounds containing one or more elements in the conditions of polymerization.

6. The method according to p. 3, in which the conditions of polymerization are provided with acid.

7. The method according to any of paragraphs.5 and 6, in which the reaction product is dried at less than 800C for the formation of the material.

8. The method according to p. 7, in which the temperature is below 300C.

9. Sorbent for removal of metal ions from a liquid medium, characterized in that it is made from a material according to any one of paragraphs. 1-4.

10. Extraction of metal ions from an aqueous solution comprising contacting the aqueous solution with a mate who

 

Same patents:
The invention relates to a method of purification of flowing waters, such as the Techa river Pripyat, contaminated by the accident at the Mayak and Chernobyl, radioactive isotopes of strontium 90, 89 and cesium 137

The invention relates to analytical chemistry of radioactive elements, and in particular to methods of radionuclides concentration with simultaneous separation of their

The invention relates to zeolites derived from anthropogenic aluminosilicate raw materials, particularly components of volatile ashes of thermal power plants, and can be used in nuclear power and chemical-metallurgical industry for the purification of liquid radioactive waste and wastewater from radionuclides ions of non-ferrous and heavy metals

The invention relates to the field of processing of liquid radioactive waste

The invention relates to the field of protection of the environment from radioactive waste

The invention relates to the field of chromatographic separation transplutonium elements and rare earth elements
The invention relates to a method for decontamination of radioactive liquids accumulated in reservoirs-pits, and having the possibility of contamination of surrounding areas as a result of tornadoes, heavy winds, and similar phenomena, with the help of mineral substances
The invention relates to the purification of natural water from radioactive isotopes of strontium 90, 89 and cesium 137 and can be used for decontamination of water water systems (rivers, ponds, lakes, reservoirs)

The invention relates to the purification technology of radionuclides from radioactive waste
The invention relates to the field of processing of intermediate level liquid waste from nuclear power plants, nuclear power plants, reprocessing plants, nuclear research centers
The invention relates to a process for the manufacture of filter material on the basis of sedimentary rocks

The invention relates to methods of extraction of heavy metal ions adsorption on cellulose sorbents from solutions of different nature, formed after carrying out a variety of technological processes, and can be used to improve membrane and sorption technologies

The invention relates to the field of adsorbents from natural raw materials

The invention relates to the field of purification from galogensoderjasimi connections

The invention relates to sinks of ammonia and hydrogen sulfide and can be used in methods of respiratory protection

The invention relates to the field of chromatography of proteins, can be used in biotechnology for purification and fractionation of enzymes

The invention relates to the production of hydrophobic sorbents for the purification of fluids from oil spills and other organic impurities and can be used in various industries for cleaning ship's bilge, ballast water, and liquidation of emergency floods of oil on the water surface

The invention relates to the field of separation of racemates of optically active compounds by chromatography

The invention relates to the field of environmental protection and concerns sorption methods of cleaning water and ground surfaces from oil products and heavy metals

The invention relates to the field of environmental protection and concerns sorption methods of cleaning water and ground surfaces from oil products and heavy metals
Up!