RU2270056C2 - Complexing sorbent, method for preparation thereof, and use - Google Patents

Abstract

FIELD: polymeric sorbents.

SUBSTANCE: invention provides complexing sorbent containing active polymer layer condensed with complexons and immobilized on a solid support selected from the following group: .epoxated cellulose, styrene/divinylbenzene copolymers, activated with chloromethyl, hydroxymethyl, sulfone chloride groups, and sulfone group-activated phenol-formaldehyde resins. Active sorption layer contains ethylenediamine or diethylenetriamine, or triethylenetetramene, or polyethylenepolyamine with copolymers, whereas complexons are selected from group including carboxyl-containing complexons, hydroxyl-containing complexons, and phosphone-containing complexons.

EFFECT: enabled sorption of unlike-valent ions of a variety of metals from aqueous solutions within a wide pH range and regeneration of sorbent by treatment with dilute mineral acid.

18 cl, 1 dwg, 2 tbl

Description

The invention relates to the field of applied chemistry, analytical chemistry, chemical technology and ecology, in particular to sorption materials, for the extraction of various metal ions from aqueous solutions and methods for producing sorbents.

The problem of water purification by adsorption of undesirable metal ions with the help of sorbing materials that retain chemical stability in the aquatic environment and do not have a harmful effect on humans is very relevant.

Recently, much attention has been paid to sorbents immobilized on a chemically inert carrier and capable of attaching various ions, including heavy metals, in an aqueous medium.

A heterogeneous complexing sorbent is known, which is polyethyleneimine immobilized on silica or silicate activated by organochlorosilanes (US, 5190660, B 01 J 20/22), which has good sorption properties with respect to ions: Cu (II), Ni (II), Zn ( II), Sn (II) in aqueous solutions, the pH of the solutions is not indicated in the patent.

The closest technical solution to the present invention is a heterogeneous complexing sorbent consisting of a dispersed or fibrous inert carrier of organic or inorganic nature and an active sorbing polymer layer, which is a polyaniline obtained by oxidative polymerization of aniline on a carrier (RU, 2141377, B 01 J 20 / 26), which has good sorption properties with respect to ions of nickel, cadmium, manganese, copper, zinc, chromium, cobalt, strontium, gold, silver, platinum, the pH of workers no solutions are indicated in the patent. However, from the above examples, we can conclude that the extraction process is carried out in a medium with a pH of about 7.0, that is, in a neutral medium.

The disadvantages of the sorbents described above are their operability only in neutral media, the relatively small spectrum of recoverable ions, the inability to simultaneously extract a wide range of multivalent ions, and the duration of the sorption process.

A known method of producing a sorbent of heavy metals, including radionuclides and mercury, which consists in the fact that sawdust of various tree species is treated with a mixture containing phosphoric acid, dimethylformamide and urea, at a boiling point for 2-5 hours (RU, 2079359, B 01 J 20/22).

The aim of the present invention is to develop a universal sorbent that extracts a wide range of multivalent ions, has a high sorption capacity in acidic, neutral and alkaline environments and does not lose its activity when reused.

When creating the invention, the task was to develop a sorbent, immobilized on a carrier chemically inert in an aqueous solution, a variety of chemical complexing groups joining the multivalent metal ions in the aqueous solution, including for the purpose of their concentration or selection.

The problem was solved by creating a complex-forming sorbent containing an active sorbent polymer layer immobilized on a solid carrier, characterized in that the solid carrier contains a carrier selected from the group consisting of: pre-epoxidized cellulose; synthetic styrene-divinylbenzene copolymers previously activated with chloromethyl or hydroxymethyl or chlorosulfonic groups; phenol-formaldehyde resin previously activated by sulfo groups, and the active sorbent layer contains a polymer condensed with complexones.

Moreover, according to the invention, it is desirable that the cellulose be selected from the group comprising microcrystalline cellulose, fibrous cellulose, waste from processing plant materials.

In addition, according to the invention, the solid carrier may comprise an activated synthetic polymer composition.

Moreover, according to the invention, the polymer of the active sorbent layer may be a polymer selected from the group consisting of ethylene diamine, or diethylene triamine, or triethylene tetraamine, or tetraethylene pentamine, or a polymer amine, or ethylene diamine condensed with copolymers.

In addition, according to the invention, the polymeric amine may be polyethyleneimine.

Moreover, according to the invention, the polymer of the active sorbent layer can be condensed with the same complexons.

In addition, according to the invention, the polymer of the active sorbent layer can be condensed with various chelators.

,

.Moreover, according to the invention, the complexones can be selected from the group consisting of carboxyl-containing complexones with the fragment —NHCH ₂ COOH, —N (CH ₂ COOH) ₂ , complexones with phosphonic groups —N (CH ₂ PO ₃ H ₂ ) ₂ , hydroxyl-containing complexones with fragments - = NCH ₂ CH ₂ OH,

,

.

Moreover, according to the invention, the active sorbent layer may contain complexones in any combination thereof and in any quantitative ratio.

The problem was also solved by creating a method for producing a complexing sorbent, including immobilization on a solid carrier of an active sorbent layer containing a polymer, characterized in that a carrier selected from the group consisting of: pre-epoxidized cellulose is used as a solid carrier; synthetic styrene-divinylbenzene copolymers previously activated with chloromethyl or hydroxymethyl or chlorosulfonic groups; phenol-formaldehyde resin, previously activated by sulfo groups, and polymers of the immobilized sorbent layer are condensed with complexones.

Moreover, according to the invention, epoxidized cellulose is obtained by treating cellulose with epichlorohydrin.

In addition, according to the invention, it is advisable to choose cellulose from the group comprising microcrystalline, fibrous cellulose and waste from processing plant materials.

Moreover, according to the invention, a compound selected from the group consisting of ethylene diamine, diethylene triamine, triethylene tetraamine, tetraethylene pentamine, polymer amine, ethylene diamine condensed with copolymers is used as the polymer of the sorbing layer.

Moreover, according to the invention, it is advisable that a polymer amine having an average molecular weight in the range from about 250 to about 50,000 be used as the polymer amine.

,

.Moreover, according to the invention, the same complexones can be used as complexons, selected from the group consisting of: carboxyl-containing complexones with a fragment of —NHCH ₂ COOH, —N (CH ₂ COOH) ₂ , complexones with phosphonic groups —N (CH ₂ PO ₃ H ₂ ) ₂ , hydroxyl-containing complexons with fragments - = NCH ₂ CH ₂ OH,

,

.

,

, в любом их сочетании и любом их количественном соотношении.In addition, according to the invention, various complexones selected from the group consisting of: carboxyl-containing complexones with a fragment of —NHCH ₂ COOH, —N (CH ₂ COOH) ₂ , complexones with phosphonic groups —N (CH ₂ PO ₃ H) can be used as complexones. ₂ ) ₂ , hydroxyl-containing complexons with fragments - = NCH ₂ CH ₂ OH,

,

, in any combination of them and any quantitative ratio.

In addition, the problem was solved by creating a method for extracting metal ions and metalloids from an aqueous medium by contacting the aqueous medium with a sorbent followed by regeneration of the sorbent, characterized in that the complexing sorbent according to the invention is used as the sorbent, and the sorbent is regenerated by treating it with diluted mineral acid.

Moreover, according to the invention, the mineral acid can be selected from the group comprising nitric acid, hydrochloric acid, sulfuric acid.

The invention is further illustrated by examples of the complexing sorbent according to the invention.

Cellulose-based sorbents

Tests of sorbents No. 1-6, obtained as follows.

Mix 50 g of cellulose selected from the group comprising microcrystalline cellulose, fibrous cellulose, waste plant materials, with 450 g of 10% NaOH for 2 hours at room temperature. Then the cellulose is filtered off, squeezed and transferred to a glass with a mixture of 150 ml of epichlorohydrin and 50 ml of isopropyl alcohol. Leave for 72 hours, stirring occasionally. The cellulose is filtered off, washed with 200 ml of isopropyl alcohol, then with distilled water until the washings are neutral, then with ethanol and air-dried to constant weight.

In a flask with a stirrer, 10 g of the obtained epoxidized cellulose, 34 g of polyethylene polyamine having an average molecular weight of from about 250 to about 50,000, and 150 ml of water and stirred for 2 hours are placed, then filtered, washed with distilled water, ethanol and dried on air to constant mass. The resulting cellulose is treated with derivatives of the complexones according to the invention and stirred at 50 ° C for 2 hours, filtered and washed with distilled water until the washings are neutral. Dry at room temperature.

Sorbent No. 1 - contains epoxidized microcrystalline cellulose as an activated solid carrier, the sorbent layer is polyethyleneimine immobilized on cellulose with a molecular weight of 10000, condensed with derivatives of diethylene triamine-N, N, N ', N ", N" -pentaacetic acid.

Sorbent No. 2 - contains epoxidized fibrous cellulose as an activated solid carrier, the sorbent layer is polyethyleneimine immobilized on cellulose with an average molecular weight of 5000, condensed with derivatives of ethylenediamine-N, N, N ', N'-tetraacetic acid.

Sorbent No. 3 - contains, as an activated solid carrier, epoxidized sawdust of coniferous trees, the sorbent layer is polyethyleneimine immobilized on said carrier with an average molecular weight of 7000, condensed with 1-hydroxyethylidene diphosphonic acid.

Sorbent No. 4 - contains sawdust of deciduous trees as an activated solid carrier. The sorbent layer is diethylene triamine. As complexone, iminodimethylene phosphonic acid (OH) ₂ OP-CH ₂ -NH-CH ₂ PO (OH) _{2 is used} .

.Sorbent No. 5 - contains epoxidized microcrystalline cellulose as an activated solid carrier. The sorbent layer is tetraethylene pentamine condensed with N- (2-hydroxyethyl) glycine

.

Sorbent No. 6 - contains epoxidized fibrous cellulose as an activated solid carrier. The sorbent layer is ethylene diamine condensed with iminodimethylene phosphonic acid (HO) ₂ POCH ₂ —NH — CH ₂ PO (OH) ₂ .

The study of sorption properties of sorbents based on cellulose

Sorbents No. 1-6, obtained on the basis of microcrystalline and fibrous cellulose, have a fine fractional composition and, accordingly, high hydraulic resistance. Their use in dynamic conditions requires excessive pressure.

Static work conditions

The study of sorption properties was carried out in static conditions by a standard method. As the source, we used a multi-element standard solution - ICP multi-element standart solution IV, manufactured by E. Merck, No. 111355, containing 23 elements in dilute nitric acid, including Al, Ba, Bi, Pb, B, Cd, Ca ions, Cr, Co, Fe, Ga, In, Cu, Mg, Mn, Ni, Ag, Sr, Tl, Zn, Li, Na, K, with different degrees of oxidation. The pH of the stock solution was ~ 1.0 at 20 ° C. The pH of the stock solution was adjusted from 1.0 to 12.0 by adding the calculated amount of NaOH. The absolute amounts of elements were 200 mg per 0.25 g of sorbent.

To determine the sorption capacity (Сё), 25 ml of a diluted ICP multi-element standart solution IV solution was added to a 0.25 g sorbent sample, stirred for 30 minutes and filtered on a Schott filter. The concentration of ions remaining in solution was determined by atomic absorption spectroscopy (AAS).

The filtered sorbent was transferred to a flask, 10 ml of 2 molar nitric acid was added, stirred for 15 minutes and filtered on a Schott filter, then washed with distilled water until the washings were neutral and reused. The number of sorbent regenerations in the studies ranged from 2 ext.

The concentration of desorbed ions was determined by the AAS method. The degree of desorption was 97-99%.

The obtained research results are presented in table 1 and in the attached diagram.

Table 1. Sorbent number solution pH Initial CE, mg / g Number of regenerations Сё, mg / g after regeneration one 1.0-3.0 138 6 112 2 2.0-5.0 107 four 103 3 7.0-7.5 98 3 90 four 8.0-9.5 96 5 87 5 11.0-12.0 127 6 115 6 4.0-5.5 135 5 118

Thus, as can be seen from table 1, the sorbents No. 1-6 according to the invention at different pH of the initial solutions are extracted from aqueous solutions of metal ions with different degrees of oxidation.

At the same time, alkali metal, sodium, potassium, lithium ions are not sorbed, which is especially important, for example, during analytical work, when it becomes necessary to concentrate trace amounts of heavy metal ions against the background of significant amounts of sodium ions.

From the presented diagram, which shows the enrichment coefficients Kd in the values of the logarithms Kd (log Kd), it can be seen that almost all elements of the standard solution are maximally sorbed in the pH range of the solution from 1.0 to 12.0. In this case, alkali metal ions (lithium, sodium, potassium) are not sorbed and are not represented in the diagram.

Synthetic polymer sorbents

Tests of sorbents No. 7-12 obtained by the general method were carried out.

A mixture consisting of 20 g of synthetic polymers selected according to the invention, with 40 g of polyethyleneamine with an average molecular weight of from about 250 to about 50,000 in 100 ml of dimethyl sulfoxide (DMSO) was heated at 77-80 ° C for 1 hour with constant stirring. The precipitate was filtered off, washed on a DMSO filter (3 × 50 ml) and dried in vacuo to constant weight.

Then, a mixture of 20 g of the obtained aminated synthetic polymer with 38 g of derivatives of the complexones according to the invention in 200 ml of DMSO was heated at 55-65 ° C for 2 hours. The mass was cooled to 15-20 ° C, the precipitate was filtered off, washed first with 50 ml of DMSO, then with 200 ml of hot water, then with 200 ml of a 3% aqueous solution of sodium hydroxide, additionally suspended in 200 ml of a 3% aqueous solution of sodium hydroxide and left for 15-20 hours. The precipitate was again filtered off, washed with water until the washings were neutral (pH 7.0). Dried at 60 ° C to constant weight. Sorbents were obtained:

Sorbent No. 7 is a sulfonated copolymer of styrene with divinylbenzene, aminated with ethylene diamine and containing various complexones as complexones: diethylene triamine-N, N, N ', N ", N" -pentaacetic acid and iminodimethylene phosphonic acid.

Sorbent No. 8 is a chloromethylated copolymer of styrene with divinylbenzene, aminated with polyethyleneimine with an average molecular weight of 50,000 and containing N- (2-hydroxyethyl) aminoacetic acid - (HOCH ₂ CH ₂ -NH-CH ₂ COOH) as a complexon.

Sorbent No. 9 is a hydroxymethylated styrene-divinylbenzene copolymer aminated with triethylenetetraamine and containing N- (2-hydroxyethyl) diethylene triamine-N, N ', N ", N" -tetramethylene phosphonic acid as a complexon.

Sorbent No. 10 is a sulfonated copolymer of styrene with divinylbenzene, aminated with tetraethylene pentamine and containing aminodiacetomethylene phosphonic acid as a complexone.

Sorbent No. 11 is a sulfochlorinated copolymer of styrene with divinylbenzene, aminated with polyethyleneimine with an average molecular weight of 250 and containing nitrilotriacetic acid as a complexon.

Sorbent No. 12 is a sulfonated phenol-formaldehyde resin, aminated with a copolymer of propylene with ethyleneimine with an average molecular weight of 3000 and containing HOOCCH ₂ -NH-CH ₂ PO (OH) ₂ as complexone.

The study of sorbents based on synthetic polymers

The study of sorbents No. 7-12 was carried out in a dynamic mode.

Working conditions. A column of 100 mm high, an inner diameter of about 3 mm, was loaded with 1 g of sorbent, a pressure vessel with a diluted ICP multi-element standart solution IV was installed at a height of about 1 m above the column. The actual transmission rate of the standard solution through the sorbent bed was about 15 column volumes per hour (rpm) in accordance with GOST 20255.2-74. In studies, sorbents were used repeatedly, subjecting them to regeneration as follows: two column volumes of diluted mineral acids were passed through a sorbent saturated with metal ions and washed with distilled water until the washings were neutral. The number of sorbent regenerations ranged from 2 to 6. The rate of transmission of the solutions through the regenerated sorbent was about 12 kb / h.

The results obtained in the study of sorbents No. 7-12 are presented in table.2.

Table 2. Sorbent number solution pH Initial CE, mg / g Bandwidth, k.ob / h. Number of regenerations Сё, mg / g, after regeneration 7 1.0-2.0 384 fifteen 6 349 7 9.5-10.0 367 fifteen four 327 8 3.0-4.7 341 fourteen 3 332 9 2.0-3.8 359 13 four 340 9 12.0 348 eleven 3 314 10 4.8 323 fifteen 2 318 eleven 7.0-8.0 375 12 5 367 12 1.0-2.5 396 fourteen 6 328 12 11.5 389 fourteen 5 330

As can be seen from table 2, the sorbents No. 7-12 according to the invention, at different pH of the initial solutions, metal ions with different oxidation states are extracted from aqueous solutions. Moreover, the sorption capacity of sorbents based on synthetic polymers (sorbents No. 7-12) is 3-4 times higher than the sorption capacity of sorbents based on cellulose (sorbents No. 1-6). The enrichment coefficients Kd thus obtained are similar to those presented on the attached diagram for sorbents No. 1-6.

In this case, alkali metal, sodium, potassium, lithium ions are also not sorbed, which is especially important when using sorbents in an industrial environment, for example, for treating wastewater with a high content of alkali metal salts, in particular sodium chloride, from heavy metal ions.

Thus, the proposed universal complexing sorbents are able to optimally extract multivalent metal ions from aqueous solutions at any pH-value both under static conditions and in a dynamic mode. A significant advantage of the sorbents according to the invention in comparison with the known ones is their repeated use ability, which allows to reduce the economic costs of analytical and treatment work.

Complexing sorbents according to the invention can be manufactured on an industrial scale by the methods according to the invention using affordable inexpensive raw materials using low-waste technologies.

Claims (18)

1. Complex-forming sorbent containing an active sorbent polymer layer immobilized on a solid carrier, characterized in that the solid carrier comprises a carrier selected from the group consisting of pre-epoxidized cellulose; synthetic styrene-divinylbenzene copolymers previously activated with chloromethyl or hydroxymethyl or chlorosulfonic groups; phenol-formaldehyde resin previously activated by sulfo groups, and the active sorbent layer contains a polymer condensed with complexones. 2. The sorbent according to claim 1, characterized in that the cellulose is selected from the group comprising microcrystalline cellulose, fibrous cellulose, waste from processing plant materials. 3. The sorbent according to claim 1, characterized in that the solid carrier contains a composition of activated synthetic polymers. 4. The sorbent according to claim 1, characterized in that the polymer of the active sorbent layer is a polymer selected from the group consisting of ethylene diamine, or diethylene triamine, or triethylenetetraamine, or tetraethylene pentamine, or a polymer amine, or ethylene diamine condensed with copolymers. 5. The sorbent according to claim 4, characterized in that the polymer amine is polyethyleneimine. 6. The sorbent according to claim 1, characterized in that the polymer of the active sorbent layer is condensed with the same complexons. 7. The sorbent according to claim 1, characterized in that the polymer of the active sorbent layer is condensed with various complexones. 8. The sorbent according to claim 1, characterized in that the complexones are selected from the group consisting of carboxyl-containing complexones with the fragment —NHCH ₂ COOH, —N (CH ₂ COOH) ₂ , complexones with phosphonic groups —N (CH ₂ PO ₃ H ₂ ) ₂ , hydroxyl-containing complexons with fragments -

9. The sorbent of claim 8, characterized in that the active sorbent layer contains complexones in any of the combinations and any quantitative ratio. 10. A method of obtaining a complexing sorbent, comprising immobilizing on a solid support an active sorbent layer containing a polymer, characterized in that as a solid support use a carrier selected from the group comprising pre-epoxidized cellulose; synthetic styrene-divinylbenzene copolymers previously activated with chloromethyl or hydroxymethyl or chlorosulfonic groups; phenol-formaldehyde resin, previously activated by sulfo groups, and polymers of the immobilized sorbent layer are condensed with complexones. 11. The method according to claim 10, characterized in that the epoxidized cellulose is obtained by treating the cellulose with epichlorohydrin. 12. The method according to claim 10, characterized in that the cellulose is selected from the group comprising microcrystalline, fibrous cellulose and waste from processing plant materials. 13. The method according to claim 10, characterized in that as the polymer of the sorbing layer, a compound selected from the group consisting of ethylene diamine, diethylene triamine, triethylenetetraamine, tetraethylene pentamine, polymer amine, ethylene diamine condensed with copolymers is used. 14. The method according to item 13, wherein the polymer amine is a polymer amine having an average molecular weight in the range of from about 250 to about 50,000. 15. The method according to claim 10, characterized in that the same complexones are used as complexones, selected from the group consisting of carboxyl-containing complexones with the fragment —NHCH ₂ COOH, —N (CH ₂ COOH) ₂ , complexones with phosphonic groups —N (CH ₂ PO ₃ H ₂ ) ₂ , hydroxyl-containing complexons with fragments -

16. The method according to claim 10, characterized in that various complexones are used as complexones, selected from the group consisting of carboxyl-containing complexones with a fragment of —NHCH ₂ COOH, —N (CH ₂ COOH) ₂ , complexones with phosphonic groups —N (CH ₂ PO ₃ H ₂ ) ₂ , hydroxyl-containing complexons with fragments -

, in any combination of them and any quantitative ratio. 17. A method of extracting metal ions and metalloids from an aqueous medium by contacting an aqueous medium with a sorbent followed by regeneration of the sorbent, characterized in that the complexing sorbent described in claims 1 to 9 is used as the sorbent, and the sorbent is regenerated by treating it with diluted mineral acid . 18. The method according to 17, characterized in that the mineral acid is selected from the group comprising nitric acid, hydrochloric acid, sulfuric acid.

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