DE2414521A1 - ADSORPTION AGENTS - Google Patents

Description

Priority: March 26, 1973, Japan, Ur. 33 595

The invention relates to an adsorbent. More particularly, the invention relates to one for water treatment suitable adsorbent, which consists of microbial cells, in which the microbial cells with the help of a water-soluble Polymers are crosslinked and bonded together to prevent the microbial cells from turning into finer Powder form in which water is dispersed.

With the recent development of industry, damage from industrial sewage is increasing different areas. In particular, wastewater containing a variety of toxic substances is like heavy metals, for the cadmium and mercury examples include, agricultural chemicals, oils, various organic materials, chemicals, synthetic detergents and Dyes, derived from the respective factories in public water facilities, so in different areas serious harmful influences on the population and living beings were exerted.

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As a means of preventing sewage damage, the Applicant has already developed a wastewater treatment process, where cells of various microorganisms, such as yeasts of the genus, were used as adsorbents Eumycetes, green algae of a species capable of photosynthesis, and the like. It was found that cells each these microorganisms have high adsorption activity against heavy metals such as cadmium and mercury, various water-soluble dyes and synthetic detergents, for example alkylbenzenesulfonates.

In this common sewage treatment method using of microorganisms, microbial cells are mixed with the waste water containing the toxic substance and the microbial cells that have adsorbed the poisonous substance are removed from the waste water by suitable solid-liquid separation methods severed. According to another embodiment, spleen cells are filled into a column and a Waste water is passed through the column to cause the toxic substances to be adsorbed on the microbial cells will. However, since most cells of microorganisms, such as yeast, have very small particle sizes, such as in the range from several microns to ten and several tens of microns, should be used as a means of solid-liquid separation in the wastewater treatment method described above is a highly efficient and operated at high speed Centrifugal separators can be used. On the other hand, when processing is carried out by the column method the flow rate at which the wastewater flows through the column is extremely low and it takes a long time to until the preparation is completed. Microbial cells, such as cells from yeast, green algae and bacteria, can therefore Adsorb contaminants well in wastewater; however, since they are dispersed in the water in a very fine powdery form,

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the handling of these adsorbents leads to difficulties in industrial use. These difficulties and deficiencies in the conventional sewage treatment method described above must be overcome.

The invention is based on the object of a waste water treatment method to make available using microorganisms, through which these disadvantages of the conventional method can be eliminated and the invention therefore lies in research on this method underlying.

The invention therefore relates to an adsorbent which is made up of microorganisms and a polymer. This Adsorbent is characterized in that the cells of the microorganisms with the help of a water-soluble Polymer containing functional groups capable of reacting with functional groups on the microbial cells are networked and connected to each other. In the process, large aggregates of microbial cells are formed, which can be used as a water-insoluble adsorbent.

In this description, these aggregates of microbial cells are not dispersed in water in the form of individual cells but retain their granular shape through the expression "water-insoluble microbe particles" or just referred to as "water-insoluble particles".

As already explained, microorganisms such as yeast are easily dispersed in water in the form of individual cells. The provision of complex solid-liquid separation devices is therefore essential when wastewater is treated with the aid of these microorganisms. However, if the

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Cells to be used for water treatment are granulated to form larger granular cell aggregates, which are found in wastewater cannot be dispersed in the form of individual cells, the separation of the microbial cells from a Mixture of cells and wastewater can be greatly facilitated. Even if the cells are filled into a column or column the water flow rate of the packed column can be greatly improved if these cells be granulated into larger particles prior to filling into the column.

The invention therefore eliminates the disadvantages of wastewater treatment methods Using microorganisms eliminated and wastewater treatment can be done in very economical and carried out effectively.

The water-insoluble adsorbent of the present invention is formed by connecting microbial cells together with the help of a water-soluble polymer. If this Adsorbent according to the invention is used for wastewater treatment, the disadvantages mentioned are the The usual method is eliminated and a very effective wastewater treatment method is achieved

The adsorbent according to the invention for wastewater treatment, that is obtained by connecting these microbial cells with the help of a polymer is not only very stable in water and not dispersed in the form of very fine particles, but also shows excellent adsorption activity.

To microbial cells used for the purposes of the invention belong to cells of numerous different microorganisms, such as yeast of the genus Saccharomyces, used to make various foods

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yeasts of the genus Mycotorula japonica or Torulopsis utilis, which is made with regard to the purification of sulphite pulp effluents or the production of proteins Petroleum are grown, green algae, for example green algae of the genus Chlorella or Scenedesmus, as well as bacteria. These microbial cells do not always have to be pure, they can also be mixtures of cells from two or several microorganisms can be used. According to the invention it is therefore possible as a starting material for production of water-insoluble microbe particles to use mixtures of cells from different organisms, such as excess Sludge produced in large quantities with the activated sludge method which is used as a biological wastewater treatment method.

It is well known that the outermost layer of such microbial cells consists of a hard layer known as a "cell wall" that plays a role in protecting the cell against external influences Actions plays. The chemical composition of the substance forming the cell wall is very complicated and varies greatly from microorganism to microorganism. In yeast, for example, the cell wall is mainly composed from mannan or glucan and in Gram-negative bacteria the outermost layer consists of lipopolysaccharide or Lipoprotein. However, they have in common that they contain polysaccharides as the main constituents of the cell walls. Therefore, in the outermost layers of the microbial cells, there are numerous hydroxyl groups and other functional ones Groups such as carboxyl groups or amino groups are present.

Since the cell walls of microorganisms are made up of chemical substances with a number of functional groups of the above type mentioned, it is possible by treating microbial cells with polymers that react

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with functional groups of the substances forming the cell wall "are able, such as carboxyl, hydroxyl, methylol and aldehyde groups, to connect the cells to one another with the polymers acting as crosslinking agents.

A wide variety of polymers can be used as crosslinking agents to bind microbial cells together will. Since the cell walls have hydrophilic properties, it is preferred to use water-soluble polymers as crosslinking agents to use. The following polymers, for example, can be mentioned as preferred water-soluble polymers are: methyl vinyl ether-maleic acid copolymers, vinyl alcohol-maleic acid copolymers, Polyacrylates, carboxymethyl cellulose, hydroxyethyl cellulose, polyvinyl alcohols, Melamine-formaldehyde resins, urea-formaldehyde resins, Thiourea-formaldehyde resins, guanidine-formaldehyde resins and the same. They are converted into the salt form to increase their water solubility. Briefly stated Any polymeric substance that is water soluble and can be used for the purposes of the invention to react with the substances that form the cell wall is capable, and the kind of the usable polymer is not limited to those exemplified above.

If a polymer to be used as a crosslinking agent is curable at room temperature, no heat treatment is required for binding to be performed; however, if the polymer to be used is thermally curable "it is necessary to carry out a heat treatment. In the latter case, for example, a melamine-formaldehyde resin is used preferably the polymer by adding a suitable one Curing catalyst, v / ie hydrochloric acid, To harden ammonium chloride and the like without specifically performing heating.

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24H521

It is essential that the amount of the polymer used for crosslinking be within a certain range. If the amount of the polymer is too small in comparison with the amount of the microbial cells, it is impossible to communicate with each other to obtain connected particles of sufficient hardness. If the amount of the polymer is excessive, this will Adsorptive capacity of the particles is reduced. However, the range of amounts of the polymer used is quite wide wide and is 0.5 to 25 #, based on microbial cells, and better results can be achieved if the polymer is used in an amount of 1 to 20%, based on the Microbial lines, is used.

Since the adsorbent of the present invention is very high in adsorption capacity for contaminants that are present in wastewater, such as heavy metal ions and dyes, it can can be used for the purification treatment of various types of waste water.

If the wastewater treatment using the inventive Adsorbent is carried out, the treatment steps can be greatly simplified and with high efficiency be carried out, in comparison with the process of wastewater treatment, in which microbial cells as such are used. For example, when the adsorption treatment is carried out in part, the particles can easily become after the completion of the adsorption treatment removed from the liquid mixture because the particles naturally settle in the liquid mixture, when the liquid mixture is simply left to stand after the adsorption treatment. Furthermore, if the liquid mixture passed through a filter after the adsorption treatment, wastewater in a larger amount can be treated more effectively than when using untreated

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powdery! Microbial cells.

If the adsorbent according to the invention is filled into a column and the wastewater treatment is carried out by, the column adsorption method is carried out, the highest effectiveness with the help of the invention Adsorbent "can be achieved in wastewater treatment. With the help of this column or column method a large amount of wastewater can be treated continuously and the quality of the treated water can be "can be greatly improved.

The invention is explained in more detail below with reference to examples.

example 1

Commercial baker's yeast (Saccharomyces cerevisiae) was made sufficiently washed with water and 100 g of a 0.1% aqueous solution of a water-soluble one shown in Table 1 Polymers were added to 20 g of the washed yeast. The yeast and the polymer were by sufficient Stir the mixture mixed together and the mixture was air dried to remove vtesser, and pulverized into particles about 1 mm in diameter. The particles thus obtained underwent heat treatment subjected to form water-insoluble particles. In each pail, the yeast cells became water-insoluble made when a suitable heat treatment such as that shown in Table 1 has been carried out and that water-soluble polymers are added to the yeast in an amount of 0.5 parts by weight per 100 parts by weight of the yeast had been. Furthermore, good water-insoluble particles could be obtained even when two react with each other capable polymers, such as a combination of one

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Methyl vinyl ether maleic anhydride copolymers and Hydroxyethyl cellulose, were used together.

When using the methyl vinyl ether-maleic anhydride copolymer became the characteristic properties

of the resulting particles was tested, the amount of the polymer added being adjusted to 0.5, 1, 2, 5, 10, 15, 20 and 25% by weight based on the cells. It was found that the mechanical properties of the particles were improved with an increase in the amount of the polymer added, and when the amount of the polymer added was $ 25, the particles were hardly swollen in water. When the amount of the polymer added was O ₁ 5 fo and the heat treatment applied was insufficient, it was sometimes observed that the particles disintegrated to some extent in water. When the added amount of the polymer was 1 <fa , solid particles useful as a water conditioner could be obtained. It was found that when these particles were used as water conditioners, better results could be obtained when the particles were swollen to some extent in water. When the added amount of the polymer was within a range of 1 to 20 µL , the resulting particles could adsorb heavy metal ions and other impurities at a very high adsorption rate, and good results were obtained.

However, if the amount of polymer added exceeded $ 25, the rate of adsorption was drastically decreased and the resulting particles could not be practical can be used.

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Table 1

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Polymer Weight
relationship
Yeast / polymer Heat treatment
conditions for
Insolubilize annotation Methyl vinyl ether
Maleic anhydride
Gopolymeres 100 / 0.5 120 ⁰ G, 1 hour Molecular weight
250,000 ! I 100 / 0.5 120 ⁰ G, 1 hour Molecular weight
1,500,000 Vinyl alcohol maleic
acid copolymer 100 / 0.5 150 ⁰ C, 1 hour average poly
degree of merization 500,
small maleic acid
share, 50 # Na-SaIz Sodium polyacrylate 100 / 0.5 130 ⁰ G, 2 hours Sodium salt of
Carboxymethylcellu-
loose 100 / 0.5 130 ⁰ G, 2 hours average poly
degree of merization 1050 Hydroxyäthy! Cellu
loose 100 / 0.5 160 ⁰ G, 2 hours Polyvinyl alcohol 100 / 0.5 160 ⁰ C, 2 hours Degree of saponification 86.5-
$ 89.0 average
licher polymerization
degree 1500

Example 2

69 g of a 2.9 $ aqueous solution of melamine-formaldehyde resin (Sumirez Resin 607 from Sumitomo Kagaku Kogyo KK) were added to 20 g of commercially available baker's yeast washed sufficiently with water, and the mixture was kneaded sufficiently. Water was removed from the mixture so that the residue showed no flowability, and the remaining mixture was shaped into a wire-like shape by being pressed through pinholes and cut to form fine particles. The resulting particles were sufficiently dried in air and 5 STUN, the heat-treated at 60 ⁰ C, said water-insoluble particles were obtained. By repeating the above procedures except that various kinds of water-soluble melamine resins and urea-formaldehyde resins were used in place of Sumirez Resin 607, water-insoluble microbial particles could similarly be obtained.

Example 3

10 g of a 10 $ aqueous solution of melamine-formaldehyde resin (Sumirez Resin 613 by Sumitomo Kagaku Kogyo K.K.) to 10 g of one was sufficiently washed with water given commercial baker's yeast. Hydrochloric acid was added to the mixture as a catalyst to catalyze the Condensation reaction of the polymer was added, the pH of the resulting slurry being adjusted to 4.5 became. Then water was removed from the slurry, so that the residue showed no flowability, and the remaining mixture was squeezed through Pressed fine holes into a wire-like shape and cut into fine particles. The particles thus obtained were air dried and at room temperature for three days

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allowed to stand to produce water-insoluble particles. When the particles thus obtained were ^{vigorously shaken in water at 60 °} C. for more than three hours, the particles were hardly broken and it was found that they had the property of keeping their shape well in water.

If in the step of preparing the slurry 0.1 g Ammonium chloride was added in place of hydrochloric acid, similar results were obtained.

Example 4

10 g of a 1% aqueous solution of a methyl vinyl ether-maleic anhydride copolymer having a molecular weight of 1,500,000 was added to 10 g of Chlorella ellipsoidea, a green alga, and the mixture was sufficiently stirred. In the same manner as described in Example 1, fine particles were produced from this mixture and the particles were one hour at 120 ⁰ C wäriaebehandelt to obtain water-insoluble particles.

Example 5

This example illustrates the production of water-insoluble particles from cells of Micrococcus lysodeikticus, a bacterium. 50 g of a 1 $ aqueous solution of a melamine-formaldehyde resin (Sumirez Resin 613 by Sumitomo Kagaku Kogyo KK) was added to 5 g of a commercially available freeze-dried cell product of the above-mentioned microorganism, and the mixture was sufficiently stirred. Fine particles were produced from this mixture in the manner described in Example 1, and the particles were ^{heat-treated at 60 °} C. for five hours to produce water-insoluble particles.

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Example 6

Particles of 100 parts by weight of baker's yeast and 1 part by weight of a methyl vinyl ether-maleic anhydride copolymer were ^{heat-treated at 120 °} C. for one hour. Then 10 g of the water-insoluble particles produced in this way with a diameter of about 0.5 mm were placed in a glass tube with a

+2 nem inner diameter of 9 mm filled. Water containing Gd at a concentration of 10 ppm calculated as cadmium atom (using CdCl ₂ ) was continuously passed through the column and the Cd atom concentration in the effluent was determined by atomic absorption spectrometry. From the effluent, fractions of 500 ml each were collected.

The column flow rate of the water to be treated was adjusted to about 700 ml / h. The analysis values of the Cadmium atom concentrations in each fraction are summarized shown in Table 2. From this, it is easy to see that a good cadmium removal effect was obtained and that cadmium could not be detected in any substantial amount in the first 13 fractions.

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ETr parliamentary group.
(500 ml) 1 2 3 4th 5 6th 7th 8th 9 0 1 1 1 2 1 3 1 4th 1 5 1 6th 1

-K-

Table_2

Cd concentration (ppm) in the effluent

<0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02 <0.02

0.05 0.10

0.15 0.32

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Example 7

Particles consisting of 100 parts by weight of baker's yeast and 10 parts by weight of a water-soluble melamine-formaldehyde resin "were ^{heat-treated at 60 °} C. for five hours, and 10 g of the resulting water-insoluble particles having a diameter of 0.3 mm were placed in a glass tube with an inner diameter of 9 mm filled. Water,

+2
containing Hg in a concentration of 10 ppm calculated as mercury atom (using HgClp) was continuously passed through the column at a rate of about 500 ml / h and the Hg atom concentration in the effluent was determined by atomic absorption spectrometry. 35 liters of water could be treated before the Hg concentration reached 1 ppm.

Example 8

4 g of yeast cell particles with a diameter of about 0.5 mm which were insoluble by the method described in Example 2 were filled in a glass tube with an inner diameter of 9 mm. A 5 ppm methyl violet containing aqueous solution was prepared by passing it through the column at a flow rate of 500 ml / h became. The amount of dye adsorbed before the dye concentration in the effluent reached 0.5 pp, was 60 mg per gram of the yeast cell particles.

If the foregoing method steps are performed using Chlorella particles and bacteria particles prepared in accordance with Examples 4 and 5 had been prepared, loaded columns were repeated, in each case practically became the obtained the same results.

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Example 9

4 g yeast particles with a diameter of about 0.5 mm, which had been made insoluble by the method described in Example 3 were placed in a glass tube with a Inside diameter of 10 mm filled. An aqueous solution the pH of which was adjusted to 2 and the 20 ppm indigo carmine (Acid dye) was prepared by passing it through the column at a flow rate of about 200 ml / h was directed. 15 l of the dye solution could be processed before the dye concentration in the effluent reached 1 ppm. The amount of dye adsorbed was 75 mg per gram of the adsorbent.

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Claims (7)

Claims 1. Adsorbent containing microorganism cells, characterized in that it is microbial cells having, with the help of a polymer that reacts with the functional groups of cell wall components the microbial cells "are able to interact with each other are connected. 2. Adsorbent according to claim 1, characterized in that it contains cells of yeast, green algae and / or contains bacteria. 3. Adsorbent according to claim 2, characterized in that it is a cells as yeast cells Contains yeast of the genus Saccharomyces, the genus Mycotorula japonica or the genus Torulopsis utilis. 4. Adsorbent according to claim 2, characterized in that it contains cells of a green alga of the genus Contains chlorella or of the genus Scenedesmus. 5. Adsorbent according to one of claims 1 to 4 » characterized in that it is used as a polymer 409842/0770 24H521 a methyl vinyl ether-maleic acid copolymer, vinyl alcohol-maleic acid copolymer, Polyacrylate, a carboxymethyl cellulose, hydroxyethyl cellulose, a polyvinyl alcohol, a melamine-formaldehyde resin Contains urea-formaldehyde resin or a guanidine-formaldehyde resin. 6. Adsorbent according to one of claims 1 "to 5, characterized in that it is the polymer in an amount of 1 to 20 wt .- ^, based on the Microbial cells. 7. Use of an adsorbent according to one of claims 1 to 6 for the treatment of waste water, in particular of industrial wastewater. 409842/0770