RU2242276C1 - Sorbent and a method for preparation thereof - Google Patents

Abstract

FIELD: sorbents.

SUBSTANCE: invention relates to sorption materials and to methods of their preparation for a wide application in medicine, veterinary, food industry, water and solution treatment. Sorbent is composed of non-spherical alumina particles (at least 20%) and fibrous material particles and contains a component with negative surface charge and a modifier (0.1-3.0%) selected from magnesium and silicon oxides and hydroxides, or their mixtures, said negatively charged component being silicon, iron, manganese, and chromium oxide or hydroxide, or their mixture. Non-spherical alumina particles are mixed with fibrous material particles after addition to the latter above-mentioned negatively charged component. When the three components are being mixed, mixture thus obtained is activated by electric current or ultrasound, after which is added above-defined modifier and the total is stirred to give sorbent suitable for use not only in neutral and acid media but also in alkaline medium at pH up to 9.5.

EFFECT: increased lifetime of sorbent.

3 cl, 1 dwg, 4 tbl

Description

The invention relates to sorption materials and methods for their preparation for widespread use of these materials in medicine, veterinary medicine, the food industry, for the purification of water, solutions, gas emissions, in the field of chemistry, biotechnology, as sorbents, carriers for catalysts, etc.

A known sorbent and method for its production (RF patent No. 2106898, IPC: B 01 D 39/00: B 01 J 20/00; C 02 F 1/28; publ. March 20, 1998). Sorbent is a layer of materials taken in the following ratio, wt.%:

Alumina 50-95

Basalt fiber 5-50

A feature of the known method is that to obtain alumina, the ultrafine aluminum powder obtained by electric explosion of aluminum wires is oxidized in an aqueous medium, and the sorbent is formed by alternating layers of fine fiber canvas from basalt fiber and highly active aluminum oxide, while the outer layers are made of basalt fiber.

The main disadvantage of this sorbent and the method of its production is that the resulting sorbent has a high cost (at least tens of dollars per 1 kg). This is primarily due to the need to use the method of expensive ultrafine aluminum powder obtained by electric explosion of aluminum wires.

The cost of the sorbent can be reduced tenfold by the use of the sorbent that is closest in technical essence and the method of its preparation described in the next publication (F. Tepper, L. Kaledin. Filters Based on Bioactive Nanofibers // Water Conditioning and Purification. - July 2002 / p. 62-65). This sorbent is a mixture of non-spherical particles of alumina (at least 20 wt.%) And particles of fibrous material (the rest).

Such a sorbent is prepared as follows. To increase activity, nonspherical alumina particles are heated to 150-800 ° C, and then mixed with a previously prepared mixture of cellulose particles and fiberglass particles, filters with a diameter of 25 mm are formed from the obtained sorbent.

The main disadvantages of the sorbent prototype and the method for its preparation are as follows: low service life of this sorbent; the sorbent obtained by this method has a limited scope since only works in neutral and acidic environments at pH≤7.5; incomplete capture of microbiological objects (MS-2 <100%).

The main technical result of the proposed invention is to increase the service life of the sorbent by an order, because its sorption properties remained almost unchanged after continuous use of filters made from it for 48 hours. In addition, this sorbent has a wider field of application, since it works effectively not only in neutral and acidic environments, but also in an alkaline environment at pH up to 9.5. It is also important that the proposed sorbent provides complete capture of microbiological objects (MS-2 - 100%). It should be noted that the method does not require, after obtaining non-spherical aluminum particles, heating these particles to high temperatures in order to increase their activity.

The specified technical result of the proposed substance is achieved by the fact that the sorbent, consisting of non-spherical particles of aluminum oxide and particles of fibrous material, according to the proposed solution additionally contains a component with a negative surface charge and a modifier selected from the series oxide or hydroxide of magnesium, silicon or a mixture thereof in the following ratio components, wt.%:

Alumina At least 20

Component with a negative surface charge of 0.5-5.0

Modifier 0.1-3.0

Fibrous material

In addition, as a component with a negative surface charge, the sorbent contains oxide or hydroxide of silicon, iron, manganese, chromium, or a mixture thereof.

The specified technical result of the proposed method is achieved by the fact that in the method for producing the sorbent, which includes producing non-spherical alumina particles and mixing the obtained particles with particles of fibrous material, according to the proposed solution, a component with a negative surface charge is added to the fibrous material in the process of mixing three of the components, the resulting mixture is activated, and then a modifier selected from a series of magnesium oxide or hydroxide, cr mniya or mixtures thereof, and the whole was stirred again.

It is advisable in the process of mixing the three components to activate the resulting mixture to produce an electric shock or ultrasound.

The analysis of the prior art by the applicant made it possible to establish that there are no analogues that are characterized by sets of features that are identical to all the features of the claimed sorbent and its production method. Therefore, the claimed solutions meet the condition of patentability "novelty."

Search results for known solutions in this and related fields of technology in order to identify features that match the distinctive features of the prototype of the claimed solutions have shown that they do not follow explicitly from the prior art.

From the prior art determined by the applicant, the influence of the transformations provided for by the essential features of the invention on the achievement of the specified technical result is not known. Therefore, the claimed solutions meet the condition of patentability "inventive step".

An example of a specific implementation. To obtain the claimed sorbent by our proposed method, 3 g of fibrous material, namely cotton cellulose, was soaked in 600 ml of distilled water and left to swell in a closed vessel for 2 hours. A sample of 0.1 g of a component with a negative surface charge, namely goethite (FeOOH), was placed in 100 ml of water and homogenized using a mechanical stirrer for 5 min. Soaked cellulose was then mixed with a goethite suspension using a homogenizer for 10 minutes. In order to obtain nonspherical alumina particles, 0.6 g of aluminum powder (grade PA) and 4 ml of concentrated NH ₄ OH solution were added to the resulting mixture, and then they were activated using an alternating sinusoidal current of industrial frequency (50 Hz) at a current density of 0, 1 A / cm ² (on aluminum electrodes) in the temperature range of 50-90 ° C for 30 minutes In this case, the complete oxidation of aluminum powder with water took place. On the surface of the cellulose nonspherical particles of alumina were formed, namely, boehmite in the amount of 26.2% by weight of the sorbent in terms of anhydrous oxide. The photograph (figure 1) shows that almost all non-spherical alumina particles were distributed on the surface of the cellulose fibers. After this, a modifier was added, namely, 7.6 ml of a 1% suspension of SiO ₂ (silica) in water and homogenized for 5 minutes. The result is a sorbent in the following ratio of components, wt.%:

Alumina 26.2

Goethite 2.3

Silica 1.7

Cotton Pulp 69.8

Then a filter was formed from the obtained sorbent, separating water on a Buchner funnel. The filter was dried in an oven for 1 hour at 50 ° C, and then for 1 hour at 160 ° C.

We also obtained nonspherical particles of alumina on a fiber by precipitation from soluble aluminum salts in an alkaline medium. However, the sorbent obtained with their use has somewhat worse characteristics.

In addition to cellulose, fibers of glass, basalt and other materials can be used as fibrous material.

Tests of the obtained sorbent with respect to microbiological objects were carried out using the model method — the ability of the sorbent to absorb monodisperse latex balls. The validity of this approach and the measurement procedure are described in (Rodney A Knight, Eugene A Ostreicher. Measuring the Electrokinetic Properties of Charged Filter Media / Filtration and Separation, January / February 1981. - p.30-34). The specific measurement procedure was as follows. To 100 ml of distilled water was added 1 ml of a solution containing 10 ¹⁴ latex beads with a diameter of 33 nm. A filter with a diameter of 13 mm and a thickness of 1 mm was formed from the sorbent. The filter was inserted into a sealed holder and the resulting solution was passed through it. The number of latex beads in the solution passed through the sorbent was measured nephelometrically. The measurement results are given in tables 1 and 2.

One of the properties of the sorbent that characterizes its service life is the mechanical tensile strength of the sorbent before rupture.

To conduct mechanical tensile tests to rupture in accordance with GOST 11262-80 (ISO 527-2, 1993), a strip of width 8 mm, thickness 1 mm and initial length 40 mm was formed from the sorbent. The speed of the rolling grip is 0.5 mm / min. Before the test, the sorbent was soaked in distilled water for 10 minutes.

Table 1 shows the values of sorption ability and strength of the sorbent.

As can be seen from table 1, the optimum is the sorbent in which the content of the component with a negative surface charge (FeOOH) of 0.5-5.0%. Similar results were obtained when using as a component with a negative surface charge the oxides and hydroxides of silicon, manganese, chromium or mixtures thereof in an amount of 0.5-5.0 wt.%. All these substances have a negative surface charge in a neutral medium (Electrosurface phenomena in disperse systems / Edited by Prof. O.N. Grigorov and Prof. D.A. Friedrichsberg. - M .: Nauka, 1972. - p.14-23 , 32-36). The corresponding hydroxides can also be obtained by precipitation on a fiber from salts in an alkaline medium.

Table 2 shows the pH and sorption ability of the obtained sorbent. At a pH of more than 9.5, the sorbent stops working.

As can be seen from Table 2, the sorbent in which the content of the modifier is 0.1-3.0% should be considered optimal.

Similar results were obtained when magnesium oxide and hydroxide were used as a modifier, and silicon and magnesium oxides can be obtained by decomposition of their compounds.

Our comparative tests in similar conditions of the sorbent prototype and the sorbent we proposed showed that the service life of the proposed sorbent is longer, since the sorbent prototype worked for 30 minutes and then mechanically collapsed, and the proposed sorbent did not fail within 2 days of operation .

We studied the effectiveness of the proposed sorbent in relation to the bacteriophage MS-2 at pH 7.0. The test data are given in table.3.

As can be seen from table 3, the proposed sorbent 100% absorbs bacteriophages MS-2.

In addition to electric current, ultrasound was used to activate the mixture. Table 4 shows the results of efficiency with respect to the bacteriophage MS-2 sorbent obtained by activating the mixture with ultrasound at a temperature of 60 ° C for 30 minutes at a frequency of 35 kHz and a radiator power of 450 watts.

As can be seen from table 4, the sorbent obtained by activation of the mixture by ultrasound, 100% absorbs bacteriophages MS-2 at a concentration of less than 4.28 · 10 ⁶ . At higher concentrations, the effectiveness of the sorbent decreases.

Claims (4)

1. Sorbent, consisting of nonspherical particles of aluminum oxide and particles of fibrous material, characterized in that it further comprises a component with a negative surface charge and a modifier selected from the series oxide or hydroxide of magnesium, silicon or a mixture thereof, in the following ratio of components, wt. %: Alumina At least 20 Component with a negative surface charge of 0.5-5.0 Modifier 0.1-3.0 Fibrous material 2. The sorbent according to claim 1, characterized in that as a component with a negative surface charge it contains oxide or hydroxide of silicon, iron, manganese, chromium, or a mixture thereof. 3. A method of producing a sorbent, including obtaining non-spherical particles of aluminum oxide and mixing the obtained particles with particles of fibrous material, characterized in that before mixing both components, a component with a negative surface charge is added to the fibrous material, during the mixing of the three components, the resulting mixture is activated, and then a modifier selected from a series of oxide or hydroxide of magnesium, silicon or a mixture thereof is introduced and everything is mixed again. 4. The method of producing the sorbent according to claim 3, characterized in that in the process of mixing the three components, the activation of the resulting mixture is carried out by electric current or ultrasound.