RU2299087C1 - Method of manufacture of the filtering material and the filtering material - Google Patents

Abstract

FIELD: chemical industry; methods of manufacture of the filtering material.

SUBSTANCE: the invention is pertaining to the water conditioning and may be used for production of the cationic-exchanging filters of the spatially- globular structures providing the complex water purification. The method of manufacture of the filtering material provides for condensation of formaldehyde with sulforesorcin and hardening. At that the mixture of the excess of formaldehyde with sodium sulfite or potassium sulfite is aged in the conditions ensuring the synthesis of the sulfonating agent at lack of polymerization of the formaldehyde. Then the produced solution is added with resorcin and kept in the conditions ensuring the simultaneous running of the synthesis of sulforesorcin and precondensation of it and resorcin with the formaldehyde and the polycondensation of the produced preoligomers, and the subsequent hardening is conducted in the acidic medium. The filtering material includes the product of condensation of the formaldehyde with resorcin in the acidic medium and has the spatially- globular structure. At that the material contains the product of condensation of the formaldehyde with sulforesorcin and resorcin, and additionally - the functional groups - SO₃H, characterized in the IR spectrum of absorption for the material sample by the strips with the minimums of 1040 cm^-1 (the characteristic strip) and 1190 cm^-1 (the weakly expressed strip). The invention ensures production of the material effective for removal of the heavy metals from the water.

EFFECT: the invention ensures production of the material effective for removal of the heavy metals from the water.

5 cl, 3 ex, 1 tbl, 1 dwg

Description

The invention relates to water treatment and can be used to obtain cation-exchange filters of a spatially globular structure. providing comprehensive water purification, including from heavy metal cations.

The prior art polymers of a spatially globular structure (ASG polymers) with high filtration ability and used for the manufacture of filter elements are known.

PGS-polymer is a highly permeable product, non-melting and insoluble in ordinary solvents, the structure of which is formed by microglobules ranging in size from 25-30 Å to 10-14 microns. PGS material with globules of 3-7 microns in size is used for sorption processes at high transmission rates of solutions. Since the size of microglobules of PGS ion exchanger is 2 orders of magnitude smaller than that of standard granite ion exchangers (5–7 μm versus 0.5–0.7 mm), the volumetric transmission rates of solutions can reach values that are 100 times or more higher than the transmission rates of solutions through a fixed ion exchanger layer granulation (1000-2000 against 10-15 beats per hour, respectively). Microglobules in PGS ion exchanger form a regular highly permeable structure, which is due to the spontaneous self-regulating mechanism of polymer formation. The average pore size is 3-5 microns, a large unfolded surface (up to 100-150 m ² / g), a narrow range of pore size distribution (usually ± 10%) give these materials high technological properties and allow their use as filter baffles. The structure and properties of PGS ion exchanger are known, for example, from the Encyclopedia of Polymers. M .: Publishing house Soviet Encyclopedia 1972.p 652-658. Various modifications of the method for producing ASG material, for example, in accordance with A. with. USSR 1378319 dated 05.23.1985, C08J 5/20, C08G 8/22, a.s. The USSR 1023788 from 10.24.1980, С08J 9/10 and others can significantly expand the range of sizes of its pores and, thereby, increase the permeability of the sorbent.

In such a system, most of the exchange groups are located on the surface of microglobules, and mass transfer is achieved not due to the diffusion of ions from the solution into the interior of the polymer body (as is the case in ordinary ion exchangers, including macroporous ones), but due to the forced leakage of solutions through micropores polymer body. The exchange rate obeys the laws of film kinetics, and therefore the ion exchange on ASO-ion exchangers proceeds the more efficiently, the faster the solution is renewed in micropores, i.e. the exchange rate increases with increasing rate of transmission of the solution.

Filter materials with an ASG structure and methods for their preparation are known, in particular, from US Pat. No. 4,567,207, C08G 12/00. The patent protects a wide range of materials obtained by polycondensation of formaldehyde with a monomer capable of forming an ASG structure with formaldehyde in an acidic medium at pH 0.1 ... 4. The concentration of the polymer is 20 ... 65 wt.%. The pore diameter of the polymer is 0.0025 ... 10 μm, the permeability coefficient is 2 × 10 ^-7 ... 2 × 10 ^-2 cm / sec.

According to examples 5 and 6 of the known solution for the manufacture of an ASG polymer with a high filtering ability, aqueous solutions of resorcinol and formaldehyde are mixed, hydrochloric acid catalyst is introduced, and it is held for a time sufficient to form 38-40 wt.% Of the polymer. Then the suspension is poured into molds for curing and kept at room T, after which it is heated to T = 80 ... 82 ° C.

Despite the high filtration properties, materials manufactured according to the technology of US Pat. No. 4,567,207 exhibit weak ion-exchange properties in neutral and slightly alkaline environments. In acidic media, ion exchange is practically absent. These features of the behavior of the known material do not allow it to effectively remove heavy metals from aqueous media.

The ASG-polymer known from US 4,567,207, which contains the condensation product of resorcinol and formaldehyde in the presence of acid, is the closest to the claimed solution of the filter material.

The prior art method for producing sulfophenol cation exchangers of high capacity, chemical resistance and mechanical strength (AS USSR 108258, 39b, 22, 12q, 20 ₀₁ ).

According to the known solution, sulfophenol cation exchangers are obtained by condensation of monohydric or polyhydric phenols or sulfophenols, first with sulfonic acids of aliphatic or aromatic carbonyl compounds, and then with formaldehyde, in order to increase the amount of sulfo groups introduced into the cation exchange resin without increasing the amount of sulfonated carbonyl compound in the first stage of the process, for condensations with phenols or sulfophenols apply aliphatic or aromatic ketone sulfonic acids.

The known method, which is the closest to the claimed method of manufacturing a filter material (prototype), does not provide the ASG polymer with sulfo groups.

The task of the invention is to increase the operational properties of the filter material by purposefully changing its structure, which allows for the removal of heavy metals from water.

The problem is solved due to the fact that in the method of manufacturing the filter material, including the condensation of formaldehyde with sulforesorcinol and curing, the process is as follows:

- a mixture of an excess of formaldehyde with sodium or potassium sulfite is maintained under conditions ensuring the synthesis of sulfomethanol in the absence of polymerization of formaldehyde,

- resorcinol is added to the resulting solution and maintained under conditions ensuring the simultaneous synthesis of sulforesorcinol and its precondensation with resorcinol and formaldehyde,

- polycondensation and curing of the obtained foroligomers is carried out in an acidic environment. This results in the formation of sulforesorcin formaldehyde ASG polymer.

Special cases of the implementation of the proposed solutions are characterized by the following parameters:

- a mixture of an excess of formaldehyde with sodium or potassium sulfite is maintained at T = + 20 ... 30 ° C for 0.3-1 hour, while the ratio of formaldehyde: sulfite is 4.7 ... 4.9 mol / mol.

- polycondensation of foroligomers is carried out at T = + 17 ... 33 ° C, for 0.6 ... 2 hours.

- curing is carried out in two stages - first at T = + 30 ... 40 ° C for 1-2 hours, and then at T = + 85 ... 95 ° C for 16-24 hours.

The resulting filter material is characterized by the ASG structure, as evidenced by its permeability with respect to water and aqueous solutions. On the IR absorption spectrum of the material sample (drawing), bands with minima of 1040 cm ^–1 (characteristic band) and 1190 cm ^–1 (weakly pronounced band) are clearly distinguishable, corresponding to stretching vibrations of the –SO ₃ N groups. At the same time, on IR the absorption spectrum of the ASG material based on resorcinol-formaldehyde polymer such bands are absent (Figure 1). These features of the IR absorption spectrum indicate the presence in the claimed material of the associated functional groups —SO ₃ N.

The essence of the method lies in the fact that the inventive sulfonated strongly acidic cation exchange resin is obtained as a result of three-dimensional polycondensation of sulfonated resorcinol with formaldehyde.

The reaction involves several stages:

1. First, carry out the stage of synthesis of a sulfonating agent (sulfomethanol) from an excess of formaldehyde and sodium sulfite (potassium) by the reaction:

2. The resulting alkaline solution from stage 1 is poured into a reactor, where the reactions of sulfonation of resorcinol (2) and for the condensation of resorcinol and the resulting sulforezorcinol with formaldehyde simultaneously occur.

3. At the end of the stage of formation of foroligomers in the same reactor, a reaction of their condensation with formaldehyde in an acidic medium is carried out to obtain oligomers of higher molecular weight.

4. At the stage of synthesis 4, when the formation of a water-insoluble product begins, the reaction solution (emulsion) is poured into pre-prepared forms, where gelation proceeds, and then (when heated) and the mixture is completely cured to obtain a three-dimensional polymer of a spatially globular structure in the form ready for practical use of cation exchanger. By controlling the synthesis parameters, it is possible to vary the pore diameter of the obtained polymer in the range of 0.1 ... 3 μm.

It should be noted that in order to obtain the product of the ASG structure with the specified properties, it is necessary to change the parameters of the known process in a substantial way, which is not obvious to a person skilled in the art:

- the synthesis reaction is carried out in two stages - first in alkaline (pH≤10), and then in an acidic environment (1≤pH≤3). If the first stage provides the production of a sulfonating agent and foroligomers, then in the second stage (acid condensation), by adjusting the pH value, products with different pore sizes can be obtained. The largest porous polymers (average pore size 3 microns) are obtained in the most acidic medium;

- in the particular case of the implementation, the ratio of resorcinol / sodium sulfite is advisable not less than 3 mol / mol;

- the ratio of formaldehyde / sulfite can vary in the range 4.7 ... 4.9 mol / mol;

- the concentration of resorcinol in the total volume of the reaction mixture is optimal in the range of 18 ... 20 wt.%;

- the reaction temperature at all stages of the synthesis should be kept within strictly specified limits.

The invention is illustrated by the following examples.

Example 1

The ratio of resorcinol / formaldehyde / sodium sulfite = 1: 2.4: 0.33 mol / mol; [resorcinol] = 18 wt.%.

51 g of sodium sulfite (0.4 mol) is loaded into a 500 ml container containing 138 ml of 37% formalin (1.87 mol of CH ₂ O) and 142 ml of water and stirred until the latter is completely dissolved at room temperature for 1 hour, formaldehyde / sulfite ratio = 4.7 mol / mol.

In a reactor containing a solution of 135 g of resorcinol (1.23 mol) in 150 ml of water, at room temperature, a solution of the sulfonating agent obtained is poured from the vessel and stirred until the formaldehyde smell disappears completely. The temperature of the mixture is maintained in the range 42 ÷ 35 ° C. The solution was cooled to room temperature, and an acidic formalin solution (82 ml of 37% formalin (1.11 mol of CH ₂ O) and 35 ml of concentrated hydrochloric acid) was poured. Then the reaction mixture (pH 2) is stirred until cloudy at T = 28 ° C (the beginning of the formation of insoluble oligomers), and then poured into a mold from two coaxial polymer pipes with a framework in the middle, where the mixture solidifies at T = + 30 ... 40 ° C for 2 hours. After this, the mold with the hardened polymer is placed in the oven for 20 hours at T = + 85 ... 90 ° C for the final formation of the polymer of the three-dimensional ASG structure in the form of a finished product (filter cartridge). The average pore size of the polymer is 1 μm.

After conversion to the Na form, cation exchange resin in the form of such a cartridge, when used in a neutral or alkaline environment, is able to absorb 6.1 g of nickel cations from a solution with [Ni ²⁺ ] _ref = 340 mg / l.

Example 2

The ratio of resorcinol / formaldehyde / sodium sulfite = 1 / 1.6 / 0.33 mol / mol; [resorcinol] = 18 wt.%.

51 g of sodium sulfite (0.4 mol) are loaded into a 500 ml container containing 146 ml of 37% formalin (1.95 mol of CH ₂ O) and 135 ml of water and stirred until the latter is completely dissolved at room temperature for 0.3 hour, formaldehyde / sulfite ratio = 4.9 mol / mol.

In a reactor containing a solution of 135 g of resorcinol (1.23 mol) in 150 ml of water, the resulting solution of a sulfonating agent is poured at room temperature and stirred until the formaldehyde smell disappears completely. The temperature of the mixture is maintained in the range 42 ÷ 35 ° C. The solution is cooled to room temperature and then a solution of phosphoric acid (34 ml of 78 wt.% In 56 ml of water) is poured into it. Then the reaction mixture is stirred (pH ≈ 3) until cloudy at T = 33 ° C (the beginning of the formation of insoluble oligomers), and then poured into a mold from two coaxially arranged polymer pipes with a framework in the middle, where the polymer solidifies for 1 hour. After this, the mold with hardened polymer is placed in the oven for 16 hours at T = + 90 ... 95 ° C for the final formation of a three-dimensional ASG structure in the form of a finished product (filter cartridge). The average polymer pore size is 0.1–0.3 μm. After conversion to the Na form, cation exchange resin in the form of such a cartridge, when used in a neutral or alkaline medium, is able to absorb 6.5 g of iron cations from a solution with [Fe ²⁺ ] _ref = 290 mg / l.

Example 3

The ratio of resorcinol / formaldehyde / sodium sulfite = 1 / 1.5 / 0.33 mol / mol; [resorcinol] = 18 wt.%. At room temperature for 1 hour; formaldehyde / sulfite ratio = 4.7 mol / mol.

In a reactor containing a solution of 135 g of resorcinol (1.23 mol) in 150 ml of water, a solution of a sulfonating agent is poured from the container at room temperature and stirred until the formaldehyde smell disappears completely. The temperature of the mixture is maintained in the range of 46 ° C ÷ 31 ° C. The solution is cooled to room temperature and then a solution of hydrochloric acid (34 ml of concentrated hydrochloric acid in 85 ml of water) is poured into it. Then the reaction mixture (pH ≈ 1) is stirred until cloudy at T = 28 ° C (the beginning of the formation of insoluble oligomers), and then poured into a mold from two coaxially arranged polymer pipes with a framework in the middle, where the polymer solidifies for 2 hours at T = + 30 ... 40 ° C. After this, the mold with the hardened polymer is placed in the oven for 18 hours at T = + 90 ... 95 ° C for the final formation of a three-dimensional ASG structure in the form of a finished product (filter cartridge).

The average pore size of the polymer is 3 microns.

Cation exchange resin in the form of such a cartridge, when used in an acidic medium, is capable of absorbing 2.5 g of calcium cations from a solution with [Ca ²⁺ ] _ref = 1400 mg / L at pH 3.5.

The synthesis conditions in examples 4 ÷ 6 (with the exception of those given in table 1) are similar to example 3.

Table 1. Example No. The ratio of resorcinol / formaldehyde / sulfonating agent The time to obtain sulfonating agent, min Cure time The average pore size, microns The amount of sorbed Ca ²⁺ , g at +30 ... + 40 ° С When temperature controlled Ex 4 1 / 1.5 / 0.33 60 2 eighteen 3 2.8 Ex 5 1 / 1.5 / 0.33 thirty one eighteen 3 2.5 Ex 6 1 / 1.5 / 0.33 twenty 2 16 3 2.5

The following reagents were used to implement the complex invention, which includes two objects - a method and a material connected by a single inventive concept according to the examples disclosed above:

Resorcinol brand "Mitsubishi";

Formalin 37% GOST 1625-98;

Sodium sulfite GOST 246-41;

Hydrochloric acid GOST 3118-77;

Phosphoric acid GOST 6552-80.

Claims (5)

1. A method of manufacturing a filter material, including the condensation of formaldehyde with sulforesorcinol and curing, characterized in that a mixture of an excess of formaldehyde with sodium sulfite or potassium is maintained under conditions ensuring the synthesis of a sulfonating agent in the absence of formaldehyde polymerization, then resorcinol is added to the resulting solution and maintained under conditions ensuring the simultaneous synthesis of sulforezorcin and its precondensation and resorcinol with formaldehyde, and the polycondensation of the obtained foroligome the ditch and subsequent curing are carried out in an acidic environment. 2. The method according to claim 1, characterized in that the mixture of an excess of formaldehyde with sodium or potassium sulfite is maintained at T = 20 ÷ 30 ° C for 0.3-1 hours, while the formaldehyde / sulfite ratio is 4.7. ..4.9 mol / mol. 3. The method according to claim 1, characterized in that the polycondensation of foroligomers is carried out at T = 17 ÷ 33 ° C, for a time of 0.6 ... 2 hours 4. The method according to claim 1, characterized in that the curing is carried out in two stages - first for 1-2 hours at T = 30 ÷ 40 ° C, and then for 16-24 hours at T = 85 ÷ 95 ° C . 5. The filter material, including the condensation product of formaldehyde with resorcinol in an acidic medium, has a spatially globular structure, characterized in that the material contains the condensation product of formaldehyde with sulforesorcinol and resorcinol, and additionally functional groups — SO ₃ H, characterized on the IR absorption spectrum the material sample in stripes with minima of 1040 cm ^-1 (characteristic band) and 1190 cm ^-1 (weakly pronounced band).