RU2300409C2 - Filtering material - Google Patents

Abstract

FIELD: environmental protection; production of the filtering materials.

SUBSTANCE: the invention is pertaining to water treatment, to be exact -to the means for purification of water from fluorides. The material produced according to the invention may be used for purification of the drinking water from the water pipelines and the freshwater springs. The filtering material contains the product of the dynamic interaction - the activated alumina with the water solution of aluminum sulfate and additionally the target additive expanding the filterability of the material and ensuring adjustment of pH of the filtrate up to the values allowing to use the filtrate for a drinking without additional purification. As the target additive may be used: the activated charcoal; the mixture of dolomite with the cation-exchange resin; the mixture of the cation-exchange resin and the anion-exchange resin in the carbonate form. The technical result of the invention consists in the extension of the filterability of the filtering material, simplification of the process of purification of the water containing fluoride-ions, reduction of its net cost.

EFFECT: the invention ensures the extension of the filtering material filterability, simplification of the process of purification of the water containing fluoride-ions, reduction of such a water net cost.

5 cl, 9 tbl, 9 ex

Description

The claimed invention relates to water treatment, and more specifically to a means of purifying water from fluorides. The material made according to the invention can be used to purify drinking water from a water supply system and freshwater sources.

The property of fluoride to serve as a biocatalyst of mineralization processes, contributing to the binding of calcium phosphate to tissues, is used for therapeutic purposes in osteoporosis, osteomalacia, rickets and other diseases that occur with impaired bone mineralization. Drinking water containing high doses of fluorine in combination with calcium has a positive effect on the body's resistance to radiation damage caused by gamma radiation or incorporation, helping to reduce the concentration of radionuclides in the teeth and skeleton.

At the same time, the unfavorable effect of fluorine compounds on the body is well known when they are increased both with drinking water and in the conditions of some industries, which is manifested in the occurrence of tooth fluorosis, impaired mineralization of bone tissue and ligaments, leukopenia, bradycardia, hypotension, and physiological disorders functions of the autonomic and central nervous system, colloid degeneration of thyroid tissue. Some scholars have expressed the view that, with excessive intake of fluoride, as an inhibitor of many enzymes, it can inhibit intracellular synthesis processes, reduce immunity and accelerate physiological aging.

When the concentration of fluoride in water is up to 1.5 mg / l, the negative consequences of its effect on health, except in rare cases of mild fluorosis, are not described in the literature. In connection with the above, SanPin 2.1.4.1074-01 on drinking tap water legalized the maximum permissible concentration of fluorides in drinking water - 1.5 mg / l.

If this value is exceeded in natural water, it becomes necessary to remove excess fluorides.

Water is defluorinated by reagent methods and filtration, including membrane filtration, which are based on sorption processes.

Reagent methods for removing fluorine from water are based on sorption of magnesium hydroxide (g.o.) or coagulants of aluminum or iron salts, for which the source water is coagulated, flocculated, then sludge is removed from g.o. metals in sedimentation tanks, filters, disinfect and serve in clean water tanks, and sludge from g. (sludge-coagulate) discharged into the sewer (G. G. Rudenko, I. T. Goronovsky. Removing impurities from natural waters at water stations. K .: Budivelnik. 1976).

An effective method is the defluorination of water by treating it with an aluminum-containing compound containing basic aluminum chloride (SU 261996, 85 b 1/01).

A known method of fluoride removal, including treatment with alkaline reagents, sorption in the suspended layer in the contact chamber at a concentration in the suspended layer in the contact chamber of 50-100 g / l and at a water pH of 9-9.5 (SU 947066, C02F 1/28). The method includes two stages of purification - sorption of ions in the contact chamber and separation of the precipitate during filtration.

According to RU 2036844, C02F 1/28, the cleaning method consists in introducing into the waste water to be treated an adsorbent - pre-neutralized white sludge obtained by autoclaving silicon from aluminate solutions of alumina production, followed by mixing and separation of liquid and solid phases (for example, by filtration or upholding). The adsorbent is introduced in a mass ratio (10-12): 1 to the amount of sodium fluoride contained in wastewater.

Known methods are intended for industrial water treatment and require reagents of complex composition and special equipment.

The Dolphin drinking water purification device (RU 2157719, B01D 24/16) is designed to purify drinking water from inorganic and organic substances, including compounds of lead, cadmium, chromium, copper, zinc, iron, strontium and other metals, fluorine as well as organochlorine compounds. The combination of dissimilar layers of materials for mechanical filtration and chemical treatment with flow dividers of a special configuration, which provides intensive mixing of water masses at the surface of the layers, can increase the efficiency and speed of water treatment while increasing the life of the device without regeneration.

It is known to use a suspension of bentonite clay in a solution of aluminum-containing coagulant with a pH of 3.0-3.2 for a mass ratio of Al ₂ O ₃ and bentonite clay 1: (5 ... 7) for defluorination of natural waters. The suspension is prepared by intensively mixing clay in a coagulant solution for 20-40 minutes. After entering the reagent and mixing, the water is clarified by settling and filtered. The use of the suspension can improve the efficiency of the action of aluminum salts.

The prior art filter media manufactured by TRAMFLOC. Information about the company and the filter media are presented in an article on the website at www.tramfloc.com. A copy of the article is attached to the application. Known material contains modified activated alumina (represents the product of the interaction of alumina and an aqueous solution of aluminum sulfate under static conditions), which improves the efficiency of water purification from fluoride ions.

However, this sorbent has a narrow filtering ability - it effectively removes only fluoride ions, and during the filtration process it acidifies water to pH≤5, which does not allow its use in single-stage filters (for example, jugs) for purification of drinking water without additional conditioning of the filtrate.

Known material on the technical nature of the closest to the claimed solution and selected by the applicant as a prototype.

The objective of the invention is to expand the filtering ability of the filter material, simplifying the technology of purification of water containing fluoride ions, and reducing its cost.

The problem is solved due to the fact that the filter material, including the product of the interaction of activated alumina with an aqueous solution of aluminum sulfate, contains the product of the dynamic interaction of activated alumina with an aqueous solution of aluminum sulfate and additionally a target additive that extends the filtering ability of the material and allows the pH of the filtrate to be adjusted to allowing you to use it for drinking.

As the target additives can be used:

- Activated carbon;

- a mixture of dolomite with a cation exchange resin;

- a mixture of cation exchange resins and anion exchange resins in carbonate form.

When using activated carbon, the optimal ratio of components by volume is in the range of 3: 1 ... 4: 1.

When using a mixture of dolomite with a cation exchange resin, the optimal ratio of components by volume is 6.7: 1: 1 ... 20: 6: 1.

When using a mixture of cation exchange resin and anion exchange resin in carbonate form, the optimal ratio of components by volume is in the range of 6.6: 1: 1 ... 12.5: 2.8: 1.

One of the significant advantages of combining the above components in one composition is to increase the efficiency of the purification process by ensuring the removal of active chlorine, iron, and other impurities, simplify the process of water purification, and reduce costs by combining the conditioning stage of the pH of the filtrate with filtration itself.

It is also important to note that by selecting the particle size distribution of the components of the claimed composition, it is possible to achieve conditions when water will pass through the filter element by gravity. This is extremely important for cartridges for household filter jugs.

Table 1 presents the data on the optimal particle size distribution of the components of the composition.

Table 1 Al oxide Activated carbon Dolomite Cation exchanger Granule size mm 1 ... 2 0.5 ... 2 1 ... 2 0.3 ... 1.2 (standard granule size of most industrial products)

Compositions that allow gravity of water to flow, regardless of the ratio of components, are prepared by mixing the components in a dry form on any equipment suitable for this purpose, while the anion exchange resin can be either in granules or in the form of at least one layer of granular material.

The most important factor ensuring the long-term performance of the material is its capacity for fluoride ions.

In the solution prototype, in order to increase the capacity of the filter material, a static surface treatment of activated alumina with its salts (in particular sulfate) is provided.

In this invention, a dynamic method is used to modify the surface of Al ₂ O ₃ granules, which consists in repeatedly passing an aqueous solution of Al ₂ (SO ₄ ) ₃ ([Al ³⁺ ] = 3 ... 5 g / l) through a layer of Al ₂ O granules ₃ for 1 ... 2 hours in the circulation mode.

The filter operates with a filter material made according to the invention as follows.

Filtered water passes through the filter material at a speed of no more than 50 beats per hour (optimally 30 beats per hour), where it is cleaned of fluoride ions, active chlorine, iron, and other impurities while the pH of the filtrate reaches a value of 6.0. ..7.5. Further, purified water suitable for drinking enters the collector or directly to the consumer. In this case, the supply of purified water to the filter can be carried out both by force (for example, using a pump), and by gravity (with an optimal particle size distribution of the mixture).

The effectiveness of water purification by the claimed material is illustrated by the following examples.

Example 1

The filtering material is a mixture of granules of the product of interaction in the dynamic mode of activated alumina with an aqueous solution of aluminum sulfate (modified alumina) and activated carbon of the 207C grade 20 × 50 composition: 200 ml of modified alumina and 50 ml of coal. The composition is used in the cartridge to the filter jug. The ratio of the components is 4: 1.

Granulometric composition: modified Al oxide - 1 ... 2 mm. Activated carbon - 0.5 ... 2 mm. Water through the mixture is filtered by gravity.

The results of water treatment with a filter jug with a cartridge according to Example 1 are presented in table 2. Cartridge resource - 140 l of water.

Example 2

The filtering material is a mixture of granules of the product of interaction in the dynamic mode of activated alumina with an aqueous solution of aluminum sulfate (modified alumina) and activated carbon of the 207C grade 20 × 50 composition: 200 ml of activated alumina and 66 ml of coal. The composition is used in the cartridge to the filter jug. The ratio of the components is 3: 1.

Granulometric composition: modified Al oxide - 1 ... 2 mm, activated carbon - 0.5 ... 2 mm. Water through the mixture is filtered by gravity. The results of water treatment with a filter jug with a cartridge according to Example 2 are presented in table 3. Cartridge resource - 120 l of water.

table 2 Volume
Filtrate Options pH standard 6 ... 9 [F ^- ], mg / l, MPC = 1.5 mg / l [Act. chlorine], mg / l, MPC = 1.2 mg / l [Fe], mg / l, MPC = 0.3 mg / l PMO, mg О ₂ / l, MPC = 5 mg / l Filtration rate, ml / min Source water 6.2 5 1.0 0.6 3.3 - twenty 6.1 0.1 0.3 0.4 1.0 130 fifty 6.1 0.3 0.33 0.34 2.2 130 one hundred 6.15 0.33 0.31 0.36 2.1 90 140 6.6 1.15 - - - 90 Table 3 The volume of filtrate l Options pH standard 6 ... 9 [F ^- ], mg / l, MPC = 1.5 mg / l [Act. chlorine], mg / l, MPC = 1.2 mg / l [Fe], mg / l, MPC = 0.3 mg / l PMO, mg О ₂ / l; MPC = 5, mg / l Filtration rate, ml / min Source water 6.1 5 1.0 0.5 3.3 - twenty 6.1 0.1 0.3 0.3 1.0 170 fifty 6.1 0.3 0.32 0.33 2.2 170 one hundred 6.3 0.33 0.31 0.3 2.1 140 120 6.6 1.15 - 0.4 - 160

Example 3

The filter material is a mixture of granules of modified alumina (according to Example 1) with a size of 1 ... 2 mm, dolomite (granule size of 1 ... 2 mm) and granular cation exchange resin Dowex HCR (contains groups - SO ₃ Na) (size granules 0.3 ... 1 mm) of the following composition: per 200 ml of modified Al ₂ O ₃ - 30 ml of dolomite and 30 ml of resin. Water through the cartridge is filtered by gravity. The ratio of the components is 6.7: 1: 1.

The results of water purification in a filter jug with such a cartridge are presented in table. 4. Cartridge resource - 150 l of water.

Table 4 The volume of filtrate, l Water parameters pH standard 6 ... 9 [F ^- ], mg / l, MPC = 1.5 mg / l [Fe], mg / l, MPC = 0.3 mg / l PMO, mg О ₂ / l, MPC = 5 mg / l Filtration rate, ml / min Source water 6.6 5 0.5 2.2 - twenty 6.5 0.1 - - 105 fifty 6.4 0.12 0.21 1.7 80 one hundred 7.25 0.44 - - fifty 140 7.3 1.5 0.15 2.1 thirty

Example 4

The filtering material is a mixture of granules of modified alumina 1 ... 2 mm in size, dolomite (granule size 1 ... 2 mm) and granular cation exchange resin Dowex HCR (contains groups - SO ₃ Na) (granule size 0.3 ... 1 mm) of the following composition: per 200 ml of modified Al ₂ O ₃ - 60 ml of dolomite and 10 ml of resin. Water through the cartridge is filtered by gravity. Component ratio 20: 6: 1

The results of water purification in a filter jug with such a cartridge are presented in table. 5. Cartridge resource - 130 l of water.

Table 5 The volume of filtrate, l Water parameters pH standard 6 ... 9 [F ^- ], mg / l, MPC = 1.5 mg / l [Fe], mg / l, MPC = 0.3 mg / l Filtration rate, ml / min Source water 6.6 5 0.6 - twenty 7.1 0.5 0.25 105 fifty 7.15 0.42 0.21 80 one hundred 6.85 one - fifty 110 6.9 1.2 0.15 thirty

Example 5

The filtering material is a mixture of granules 1 ... 2 mm in size modified alumina, granular Dowex HCR cation exchange resin (contains groups - SO ₃ Na) (granule size 0.3 ... 1 mm) and anion exchange resin (in CO ₃ ^2- form) of the following composition: ON 200 ml of modified Al ₂ O ₃ - 44 ml of cation exchange resin and 16 ml of anion exchange resin in the form of a layer of needle-punched non-woven anion-exchange fiber Fiban AK-22 (in CO ₃ ^2- form). Component ratio 12.5: 2.8: 1

Material is loaded into the filter jug cartridge. Cartridge resource - 130 l of water.

The results of water treatment with a filter jug with a cartridge containing the material of example 5 (water is filtered by gravity) are presented in table. 6.

Table 6 The volume of filtrate, l Water parameters pH standard 6 ... 9 [F ^- ], mg / l, MPC = 1.5 mg / l [Fe], mg / l, MPC = 0.3 mg / l PMO, mg O ₂ / l, MPC = 5 mg / l Filtration rate, ml / min Source water 6.8 5 0.67 2.2 - twenty 6.2 0.18 0.11 - 130 fifty 6.9 0.1 0.25 1.8 110 one hundred 6.15 0.66 0.28 - 115 130 6.4 1.5 0.28 2.1 90

Example 6

The filter material is a mixture of granules of modified alumina (according to Example 1), granular resin Dowex HCR (contains groups - SO ₃ Na) (granule size 0.3 ... 1 mm) and granular anion-exchange resin Purolite A-400 (in CO ₃ ^2- form) (granule size 0.3 ... 1 mm) of the following composition: per 200 ml of modified Al ₂ O ₃ - 30 ml of cation exchange resin and 30 ml of anion exchange resin. The ratio of the components is 6.6: 1: 1. Cartridge resource - 100 l of water.

The results of water treatment with a filter jug with a cartridge containing the material of example 6 (water is filtered by gravity) are presented in table. 7.

Table 7 The volume of filtrate, l Water parameters pH standard 6 ... 9 [F ^- ], mg / l, MPC = 1.5 mg / l [Fe], mg / l, MPC = 0.3 mg / l PMO, mg O ₂ / l, MPC = 5 mg / l Filtration rate, ml / min Source water 6.8 5 0.7 2.2 - twenty 6.3 0.24 0.31 - 90 fifty 6.5 0.19 0.32 1.8 fifty one hundred 6.65 1.8 0.38 - thirty

Example 7

The filter material is a mixture of granules with a size of 2 ... 3 mm of modified alumina (according to Example 1), a layer of granular cation exchange resin Dowex HCR (contains groups - SO ₃ Na) (granule size 0.3 ... 1 mm) and a layer of granular anion exchange Purolite A-400 resins (in CO ₃ ^2- form) (granule size 0.3 ... 1 mm) of the following composition: per 600 ml of activated Al ₂ O ₃ - 60 ml of cation exchange resin and 50 ml of anion exchange resin. The ratio of the components is 12: 1.2: 1.

The results of water treatment on a bulk cartridge containing the material of example 7 (water is supplied under a pressure of 0.2 MPa) are presented in table 8.

Table 8 The volume of filtrate, l Water parameters pH standard 6 ... 9 [F ^- ], mg / l, MPC = 1.5 mg / l [Fe], mg / l, MPC = 0.3 mg / l PMO, mg О ₂ / l, MPC = 5 mg / l Filtration rate, ml / min Source water 6.8 5.0 0.5 ... 0.6 2.2 - twenty 6.0 0.78 0.31 - 400 fifty 6.2 0.86 0.32 1.9 420 one hundred 6.35 0.66 0.38 - 400 150 6.4 1.5 - 2.1 380 200 6.4 1.3 0.38 - 360 250 6.5 1.0 0.5 - 300 300 6.5 1.0 0.45 - 200 400 6.6 1.9 0.6 - 300

Resource cartridge - 450 liters of Veda.

The parameters and types of resins given in the examples do not exclude the use of other resins having the properties necessary for the implementation of the invention without changing its essence.

Information on the conditions for obtaining the product of the dynamic interaction of activated alumina with an aqueous solution of aluminum sulfate is presented in Examples 8 and 9.

Example 8

1.5 l of Al ₂ O ₃ granules with a diameter of 1 ... 2 mm are loaded into a cylindrical reactor. 20 l of a solution of aluminum sulfate with [Al ³⁺ ] = 5 g / l at a speed of 1 ... 2 beats are passed through the reactor in the circulation mode. vol./h for 1 hour. Then, the alumina is washed with an eight-fold volume of water with a low iron content ([Fe] <0.3 mg / l) and discharged wet from the reactor.

Example 9

In a cylindrical reactor load 2 l of granules of Al ₂ O _{3 with a} diameter of 1 ... 2 mm 25 l of a solution of aluminum sulfate with [Al ³⁺ ] = 3 g / l at a speed of 1 ... 2 beats is passed through the reactor in the circulation mode. v / h for 2 hours. The concentration of aluminum in the solution is once adjusted during processing. Then, alumina is washed with an eight-fold volume of water with a low iron content ([Fe] <0.3 mg / L) and is discharged wet from the reactor.

Information on the methods for determining the content of the investigated substances are given in Table 9.

Table 9 No. p / p Defined parameter MPC SanPiN 2.1.4.1074-01 DKM, GN.2.3.3.972-00 Test methods one. Total iron, mg / l 0.3 MU 08-47 / 104 2. Permanganate oxidizability (PMO), mg O ₂ / l 5.0 PNDF 14.2: 4.154-99 3. Chlorine, mg / L free bound 0.3 0.5 GOST 18190-72 four. Fluoride, mg / l 1.5 RD 52.24.360-95 5. pH 6.0 ... 9.0 GOST 2874-82

Claims (5)

1. Filtering material, including the product of the interaction of activated alumina with an aqueous solution of aluminum sulfate, characterized in that the material contains a product of the dynamic interaction of the above reagents, obtained by repeatedly passing an aqueous solution of aluminum sulfate with a concentration of 3-5 g / l for 1-2 h through a layer of granules of alumina, and additionally a target additive that provides a filtrate with a pH value that allows you to use the filtrate for drinking without conditioning. 2. The filter material according to claim 1, characterized in that, as a target additive, the material contains activated carbon in the following ratio of component volumes: product of modification: activated carbon = 3: 1-4: 1. 3. The filter material according to claim 1, characterized in that as the target additive, the material contains a mixture of dolomite with a cation exchange resin in the following ratio of component volumes: product of modification: dolomite: cation exchange resin = 6.5: 1: 1-20: 6: one. 4. The filter material according to claim 1, characterized in that, as a target additive, the material contains a mixture of cation exchange resin and anion exchange resin in carbonate form in the following ratio of component volumes: product of modification: cation exchange resin: anion exchange resin = 6.7: 1: 1 -12.5: 2.8: 1. 5. The filter material according to claim 3 or 4, characterized in that, as a cation exchange resin, the material contains a resin with —SO ₃ Na groups.