RU2550192C2 - Method of ion-exchange purification of sewage waters and technological solutions from metal ions - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention can be used in industry at the stage of fine or additional purification of water from traces of heavy metal ions, in the purification of vapour condensate in boiler houses and TPP plants in the creation of closed technological water circulation. To realise the method of ion-exchange water purification sewage waters and technological solutions are passed through a sorbent, containing hydrazide groups. as the sorbent used is activated carbon, preliminarily processed with a gas mixture of ammonia and hydrazine, taken in volume ratios of 1:2-2.5, at a temperature of 350-450°C. The method provides the removal of ions of metals with a variable valence: Cu²⁺, Zn²⁺, Ni²⁺, Cr³⁺, Fe³⁺, as well as ions of metals: Bi³⁺, Zr⁴⁺, Sr²⁺, Co²⁺ from water, with the preservation by the sorbent of the sorption activity in a wide range of the water solution pH values.

EFFECT: purification of water from traces of heavy metal ions.

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Description

The invention relates to a technology for wastewater treatment and can be used in industry at the stage of fine or additional water purification from traces of heavy metal ions, in the treatment of steam condensate in boiler rooms and at thermal power plants, including the creation of a closed technological water circulation.

A known method of purifying water from metal ions in their joint presence by filtration through copolymer sorbents containing ethylene diamine groups (copyright certificate RU No. 966023, IPC7, CL C02F 1/42, 1982). The specified method has selectivity only with respect to ferric ions (Fe ³⁺ ), which is its drawback, since its use and performance are limited when other ions are contained in water.

Known methods for the extraction of heavy metal ions by sulfonated brown coal [Ibarra J. Moliner R. Fuel Removal of heavy metal ions from wastewater with a broken sulfonated brown coal. 1984, 63, N3, p.377], peat-based sorbent [Ludwig G. Simon J. Industrial wastewater treatment of heavy metals using filters with granular peat-based sorbent. "Geol Jahrb", 1983, N6a, p. 365].

The disadvantages of such cleaning methods is the low absorption capacity of the sorbents, the high cost of regeneration, the low strength of the sorbent and, consequently, high losses during filtration.

A known method of treating wastewater from heavy metal ions by extracting them with a sorbent based on magnesia-ferrous slags [Zosin A.P. Gurevich B.I. Milovanova I.B. On the sorption properties of slag silicate. In the book. "Chemistry and technology of silicate materials." L. Science, 1971, p. 100 105], [A.P. Zosin, T.I. Primak. Purification of industrial effluents from cations of nickel, cobalt, copper, sorbent based on magnesia-ferrous slags of non-ferrous metallurgy // Chemistry and technology of inorganic sorbents: Minvuz. Sat scientific tr Perm. Polytechnics, Institute Perm, 1980, p. 92 97].

Purification of wastes from metal ions is carried out by passing the solution through a layer of sorbent. The disadvantage of this method is the low efficiency, the inability to regenerate the sorbent due to the low strength of the granules.

A known method of purification of a solution containing copper, zinc and iron from ferric ions by sorption on anion exchange resin obtained by hydrazine amination of a copolymer of methyl acrylate and divinylbenzene [Copyright certificate RU No. 528310, IPC7, cl. C08F 226/02, C08F 8/32 1975].

The disadvantage of this method is the low degree of purification of the solution from ferric ions.

A known method of purification of copper-zinc solutions from ferric ions by sorption on anion exchange resin obtained by amination with hydroxylamine copolymer of methyl acrylate and divinylbenzene [Copyright certificate RU No. 529178, IPC7, CL C08F 226/02, C08F 8/32, B010 15/04, 1975].

The disadvantage of this method is the low degree of purification of the solution from ferric ions.

The closest to the invention in technical essence and the achieved result is a method of ion-exchange treatment of wastewater and technological solutions from metal ions of variable valency by passing them through a mixture of aminocarboxylic cateonite and low-basic polymerization type anion exchange resin taken in cationic and anionic form, while using as a mixture a copolymer of methyl methacrylate, divinyl sulfide, divinylbenzene and polymethacrylic acid hydrazide, with a ratio of ethylenediamine and hydrazide g groupings in the copolymer 1: 1 [Patent RU No. 2434811), C02F 1/42, IPC 7, 01J 43/00, B01J 20/26, 2011].

The disadvantage of this method is its limited performance during the treatment of wastewater containing ions of metals such as Bi ³⁺ , Zr ⁴⁺ , Sr ²⁺ , Co ²⁺ .

The technical result of the invention is the removal from water of metal ions of variable valency: Cu ²⁺ , Zn ²⁺ , Ni ²⁺ , Cr ³⁺ , Fe ³⁺ , as well as metal ions: Bi ³⁺ , Zr ⁴⁺ , Sr ²⁺ , Co ²⁺ , while maintaining the sorbent sorption activity, wide pH values of the aqueous solution and the number of cycles of "cleaning - regeneration".

The technical result is achieved by the fact that in the method of ion-exchange wastewater and technological solutions from metal ions by passing them through a sorbent containing hydrazide groups, according to the invention, activated carbon pretreated with a gas mixture of ammonia and hydrazine taken in volume ratios is used as a sorbent 1: 2-2.5, at a temperature of 350-450 ° C.

In the proposed method, the effect of improved water treatment is achieved due to the improved structure of activated carbon. For this, the process was carried out under the following conditions: temperature 350-450 ° C, treatment with a gas mixture of ammonia and hydrazine taken in volume ratio 1: 2-2.5, the processing time was 2-5 minutes. Such process conditions make it possible to modify the porous structure of coal and increase porosity, which makes it possible for coal to acquire sorption properties from the aqueous phase of not only metal ions of variable valence: Cu ²⁺ , Zn ²⁺ , Ni ²⁺ , Cr ³⁺ , Fe ³⁺ as well as ions of the following metals: Bi ³⁺ , Zr ⁴⁺ , Sr ²⁺ , Co ²⁺ .

The technical result, which is achieved by the above set of essential features, is explained by the fact that with this cleaning method, the complex activity of the sorbent is manifested using, in addition to the structures present in activated carbon, amino groups -NH ₂ and hydrazide groups -NH-NH ₂ .

This sorbent does not lose mechanical strength in the work - regeneration cycle. A set of active groups allows you to hold a wide variety of metal ions: Bi ³⁺ , Zr ⁴⁺ , Sr ²⁺ , Co ²⁺ , without compromising the degree of purification from metal ions of variable valency: Cu ²⁺ , Zn ²⁺ , Ni ²⁺ , Cr ³⁺ , Fe ³⁺ . At the same time, water is removed, among others, from an ionic pollution, it becomes clean, suitable for use in water circulation. The method is tested in a laboratory setting.

The test results are presented in the table.

Example 1

500 ml of an aqueous solution containing ions of Cu ²⁺ , Zn ²⁺ , Ni ²⁺ , Cr ³⁺ and Fe ³⁺ at a content of 1.40 mg / l and metal ions Bi ³⁺ , Zr ⁴⁺ , Sr ²⁺ , Co ²⁺ at a content of not higher than 0.01 mg / l (traces) (see table), by gravity pass through a column 100 mm high and 11.3 mm in diameter, filled with 80% activated carbon, pre-treated with a gas mixture of ammonia and hydrazine taken in a ratio of 1: 2 by volume, at a temperature of 350 ° C. According to the results of liquid-phase chromatographic analysis, Cr ³⁺ and Fe ³⁺ ions are absent in a purified aqueous solution, Cu ²⁺ , Zn ²⁺ , Ni ^{2+ ions} do not exceed acceptable values, environmentally hazardous metal ions Bi ³⁺ , Zr ⁴⁺ , Sr ^{2 +} , Co ^{2+ are} absent, that is, the quality of water treatment is significantly improved.

Example 2

500 ml of technological solution used in metalworking manufactured by Volgogradneftemash LLC, containing Cu ²⁺ , Zn ²⁺ , Ni ²⁺ , Cr ³⁺ , Fe ³⁺ , Bi ³⁺ , Zr ⁴⁺ , Sr ²⁺ and Co ^{2 ions +} (see table), gravity is passed through a column with a height of 100 mm and a diameter of 11.3 mm, filled with 80% activated carbon, pre-treated with a gas mixture of ammonia and hydrazine, taken in a ratio of 1: 2 by volume, at a temperature of 350 ° C. According to the results of liquid-phase chromatographic analysis, there are no Cr ³⁺ and Fe ³⁺ ions in the purified technological solution, Cu ²⁺ , Zn ²⁺ , Ni ^{2+ ions} do not exceed acceptable values, environmentally hazardous metal ions Bi ³⁺ , Zr ⁴⁺ , Sr ^{2 +} , Co ^{2+ are} absent, that is, the quality of purification of the technological solution is significantly improved. The results compared with the prototype are presented in the table.

Example 3

500 ml of wastewater produced by LLC "Hardware Plant" containing ions of Cu ²⁺ , Zn ²⁺ , Ni ²⁺ , Cr ³⁺ , Fe ³⁺ , Bi ³⁺ , Zr ⁴⁺ , Sr ²⁺ and Co ²⁺ (cm table), by gravity pass through a column with a height of 100 mm and a diameter of 11.3 mm, filled with 80% activated carbon, pre-treated with a gas mixture of ammonia and hydrazine, taken in a ratio of 1: 2.5 by volume, at a temperature of 450 ° C . The treated wastewater contains Cu ²⁺ , Zn ²⁺ , Ni ^{2+ ions} in concentrations not exceeding the permissible values; environmentally hazardous metal ions Bi ³⁺ , Zr ⁴⁺ , Sr ²⁺ , Co ^{2+ are} absent, i.e. the quality of wastewater treatment water improves significantly.

The proposed method Composition (mg / L) and parameters Example 1 Example 2 Example 3 Prototype Cu ²⁺ 1.40 1.39 1.43 1.40 Zn ²⁺ 1.40 1.40 1.44 1.40 Ni ²⁺ 1.40 1.36 1.42 1.40 Cr ³⁺ 1.40 1.40 1.40 1.40 Fe ³⁺ 1.40 1.38 1.43 1.40 Metal ions (not more than 0.01 mg / l) Bi ³⁺ + + + + Zr ⁴⁺ + + + + Sr ²⁺ + + + + Co ²⁺ + + + + solution pH 3,5-5 3,5-5 3,5-5 3,5-5 The volume of purified water ml / ml ion exchanger 300 300 300 300 pH of purified water 7.0 7 7 7 The change in the volume of sorbent,% 0,0 ÷ + 0,4 0,0 ÷ + 0,4 0,0 ÷ + 0,4 0,0 ÷ + 0,4 The number of cycles "work-regeneration" without deterioration of the purified water 22 22 22 22 " Bi ³⁺ are absent are absent are absent there is Zr ⁴⁺ are absent are absent are absent there is Sr ²⁺ are absent are absent are absent there is Co ²⁺ are absent are absent are absent there is Cu ²⁺ (mg / L) 0.005 0.005 0.005 0.005 Zn ²⁺ (mg / L) 0.007 0.007 0.007 0.007 Ni ²⁺ (mg / L) 0.001 0.001 0.001 0.001 Cr ³⁺ are absent are absent are absent are absent Fe ³⁺ are absent are absent are absent are absent

Thus, the developed technical solution contains signs sufficient to obtain a new technical result, as specified by the claims.

Claims (1)

The method of ion-exchange treatment of wastewater and technological solutions from metal ions by passing them through a sorbent containing hydrazide groups, characterized in that activated carbon pretreated with a gas mixture of ammonia and hydrazine taken in volume ratios of 1: 2-2 is used as a sorbent 5, at a temperature of 350-450 ° C.