KR101126105B1 - Heavy metal adsorbent composition - Google Patents

Abstract

The present invention is Bacillus sp. KRI-02 or its related bacteria, Bacillus rickenformis and Staphylococcus sp. A heavy metal adsorbent composition containing a cell obtained by acid treatment of a bacterium selected from KRI-04 or a flexible bacterium thereof, and a method for removing heavy metal from a heavy metal-containing medium using the same. According to the present invention, heavy metals can be removed from rivers, lakes and swamps, factory drains, and the like.

Description

 Heavy Metal Adsorbent Composition {HEAVY METAL ADSORBENT COMPOSITION}

The present invention relates to a heavy metal adsorbent composition containing bacterial microorganisms and a method for removing heavy metals from heavy metal-containing media such as environmental water using the composition.

Environmental pollution by heavy metals such as cadmium, copper, zinc, chromium and lead is a problem worldwide because it is toxic to living organisms even in trace concentrations. Agglomeration precipitation method is widely adopted as a means of removing heavy metals. Although this method is low cost, it generates a large amount of sludge containing high concentrations of heavy metals and requires disposal at the final disposal site. The ion exchange method has little sludge production but is expensive and its use is limited.

Recently, a number of heavy metal removal methods using biomass such as bacteria, yeast, mold, and seaweed have been reported. Although living biomass has been reported, the use of dead biomass is practical because it does not need to be cultured in the environment. The biomass not only specifically adsorbs heavy metals such as cadmium, copper, zinc, chromium and lead, but also dissociates and recovers the adsorbed heavy metals. In addition, biomass is generally biodegradable and has the advantage of being environmentally friendly. Living biomass is, for example, after culturing bacteria, water, calcium nitrate solution (pH 4.0) (Mullen MD et al. Appl. Environ. Microbiol. 1989: 55, 3143-3149) or phosphate buffer (Kurek E et al. Appl. Environ.Microbiol. 1982: 43, 1011-1015).

As a means of using dead biomass, in addition to a method of washing after alkali treatment (Brierley et al. US Patent No. 4,992,179), and high pressure steam sterilization (J Colloid Interface Sci. 1998: 197, 185-190), cyanide Treatment with potassium and ethanol (Kurek E et al. Appl. Environ. Microbiol. 1982: 43, 1011-1015) has also been reported. Among these, Brierley et al. Reported that alkali treatment of bacteria such as Bacillus subtilis increases the amount of adsorption per unit weight of gold, silver, copper and lead. The present inventors also carried out alkali treatment of various bacteria to examine the adsorption amount of heavy metals. When the alkali treatment is performed, the amount of adsorption per unit weight certainly increases, but after the treatment, the weight of bacteria greatly decreases, and overall, alkali The treatment turned out to be not a useful method.

The inventors of the present invention have examined from the viewpoints of the bacteria treatment method and the identification of bacteria with high adsorption capacity of heavy metals, Bacillus KRI-02 or its soft bacteria, Bacillus licheniformis and Staphylococcus sp. Compared to the case where the cell obtained by acid treatment of KRI-04 or its bacteria is acid treated, the cell weight does not decrease much by the acid treatment, and the amount of heavy metal adsorption per unit weight of the cell increases, and further acid treatment The present invention has been found to be useful as a heavy metal adsorbent from being renewable by the present invention.

That is, the present invention is Bacillus sp. KRI-02 or its related bacteria, Bacillus rickenformis and Staphylococcus sp. It is to provide a heavy metal adsorbent composition containing the cells obtained by acid treatment of bacteria selected from KRI-04 or its related bacteria.

In addition, the present invention is a heavy metal containing medium Bacillus sp. KRI-02 or its related bacteria, Bacillus rickenformis and Staphylococcus sp. The present invention provides a method for removing heavy metals from a heavy metal-containing medium, which comprises treating the cells selected from KRI-04 or its flexible bacteria with a heavy metal adsorbent composition containing the cells obtained by acid treatment.

Furthermore, the present invention is Bacillus sp. KRI-02 (FERM BP-8165), Bacillus rickeniformis KRI-03 (FERM BP-8166), and Staphylococcus sp. It is to provide a bacterium selected from KRI-04 (FERM BP-8167).

The present invention also provides a heavy metal adsorption device comprising (A) at least one heavy metal adsorption tank containing the heavy metal adsorbent composition and (B) an acid containing tank.

By using the heavy metal adsorbent composition of the present invention, it is possible to efficiently remove harmful heavy metals from rivers, lakes and swamps, and plant drainage.

1 is a view showing the adsorption / elution test results for Cu of the KRI-02 strain.

Figure 2 is a view showing the adsorption / elution test results for Ni of the KRI-02 strain.

3 is a diagram showing the adsorption capacity (first and tenth times) of Teflon-containing cell beads to Cu.

4 is a diagram showing the adsorption capacity (first and tenth) of Teflon-containing cell beads to Zn.

5 is a view showing the adsorption capacity of the heat-treated cell beads to Cu.

6 is a view showing the adsorption capacity of the heat treatment cell beads to Zn.

7 is a diagram showing the adsorption capacity (first and tenth times) of the heat-treated cell beads to Cu.

8 is a graph showing the adsorption capacity (first and tenth times) of Zn of heat-treated cell beads.

9 is a graph showing the relationship between the amount of cell beads added and Zn adsorption capacity.

10 is a graph showing the relationship between the number of regeneration of cell beads and Zn adsorption capacity.

11 is a view showing the adsorption capacity of cell beads to Zn and Fe in the plating plant drainage.

12 is a view showing the adsorption capacity (repetitive use) of cell beads to Zn and Fe in the plating plant drainage.

13 is a graph showing the relationship between the adsorption capacity and the number of regeneration of Zn and Fe in the plating plant drainage.

14 is a diagram showing the adsorption capacity for Zn in the drainage in the plating plant when five adsorption tanks are used.

Fig. 15 is a graph showing the relationship between the number of regeneration and Zn adsorption capacity in the plating waste water tank.

16 and 17 are views showing an example of a heavy metal removal system in the wastewater.

FIG. 18 shows the wastewater flow to four bead baths in the system of FIG.

BEST MODE FOR CARRYING OUT THE INVENTION [

Cells used as the heavy metal adsorbent in the present invention is Bacillus sp. KRI-02 or its fungi, Bacillus rickenformis and Staphylococcus sp. It is a cell obtained by acid-processing the bacterium selected from KRI-04 or its flexible bacteria. The bacteria belonging to these specific species have the characteristic that, when acid treated, the weight of the heavy metal per unit weight increases without decreasing the cell weight. Bacillus sp. KRI-02 or its related bacteria, Bacillus sp. KRI-02 (FERM BP-8165) and its soft strains are particularly preferred. Among Bacillus rickenformis, Bacillus rickenformis KRI-03 (FERM BP-8167) and its soft strains are particularly preferred. Staphylococcus sp. Among KRI-04 or its related bacteria, Staphylococcus sp. KRI-04 (FERM BP-8166) and its soft strains are particularly preferred. Herein, the strain refers to a strain belonging to the same species as the strain and having the same heavy metal adsorption capacity as the strain.

The acid used for acid treatment of these bacteria is not particularly limited as long as it is an acid capable of killing these bacteria, but may include inorganic acids such as hydrochloric acid, sulfuric acid and nitric acid, organic acids such as acetic acid, formic acid, valeric acid, propionic acid, oxalic acid and citric acid. Can be. The acid treatment may be any condition under which bacteria are killed. For example, it is preferable that the bacteria are treated for 15 to 150 minutes in an acid aqueous solution having a pH of 0.5 to 2. In addition, it is preferable that the temperature at the time of acid treatment is the growth temperature of a microbe. In addition, it is preferable to wash the bacteria with water prior to the acid treatment.

After the acid treatment, the cells are preferably washed with water to return the pH to neutral. The acid treated cells may be used as suspensions in water or the like, but are preferably dried and used by means such as lyophilization, spray drying, and heating.

The obtained acid-treated cells have a very low cell weight reduction compared to the alkali-treated cells, and the heavy metal adsorption capacity is increased compared to the untreated cells. Thus, acid treated cells are particularly useful as heavy metal adsorbents compared to untreated live cells and alkali treated cells.

Organisms including bacteria and the like are composed of proteins, lipids, glycosides and the like. Therefore, alkaline treatment dissolves proteins and acidic substances, solubilizes most of the biological components by hydrolysis, leaving only some insoluble components. On the other hand, when acid-treated bacteria, proteins are denatured and remain, and not only metal ions which are cations are removed, but also alkaline substances are removed, and many cavities are formed inside bacteria, and ions such as heavy metal ions are easily penetrated, It is thought that the binding site of heavy metal in bacteria can be utilized to the maximum.

Heavy metals that can be adsorbed by the acid-treated cells of the present invention include Ag, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Pd, Zn and the like.

The heavy metal adsorbent composition of the present invention may be the acid-treated cell itself, but may be in the form of containing an aqueous carrier or a solid carrier. Water or aqueous solution is mentioned as an aqueous carrier, A water suspension is mentioned as the composition. Examples of the solid carrier include various inorganic carriers and resin carriers. In addition to the acid-treated cells, the composition may contain other heavy metal adsorbents, plasticizers, emulsifiers, lubricants, antistatic agents, foaming agents, flame retardants, fillers, reinforcing agents and the like.

The acid treated cell concentration in the heavy metal adsorbent composition is 5 to 100% by weight, preferably 10 to 100% by weight, particularly preferably 20 to 100% by weight, in terms of dry cell weight.

Examples of the inorganic carrier for supporting the acid treated cells include silica gel, alumina, glass, diatomaceous earth, Teflon, and the like. Moreover, cellulose, acrylamide derivative, polysulfone, polyvinyl alcohol, polystyrene, calcium alginate, carrageenan, polyethylene imine etc. are mentioned as a resin support | carrier. These inorganic carriers and resin carriers may be used alone or in combination.

The acid treated cells are preferably used in the form of cell beads, supported on the inorganic carrier or the resin carrier. Of these, cell beads in which the acid-treated cells are supported on the resin carrier are particularly preferable. The weight ratio of the acid treated cells in the cell beads to the inorganic carrier or the resin carrier is preferably 1:10 to 10: 1, more preferably 1: 5 to 5: 1.

As a method for producing cell beads, a method of dropping a mixture of an acid-treated cell and the carrier and a medium such as liquid nitrogen (dropping method); The method (assembly method) etc. which spray the mixed solution of an acid-treated cell and the said carrier on the nucleus using nucleus, such as lactose, are mentioned. The cell beads obtained by this granulation method can improve the water resistance by heat treatment. In addition, it is possible to improve the adsorption of heavy metals by making it porous by freeze-thawing treatment. Here, it is preferable to perform heat processing for 2 to 30 minutes at 120-250 degreeC, especially 5 to 30 minutes at 150-200 degreeC.

When the cell beads are aggregated during the heavy metal adsorption treatment, the contact efficiency with the heavy metals is lowered. Therefore, it is preferable to suppress the aggregation of the cell beads. As the aggregation suppression technique, it is preferable to add additives such as teflon powder, dibutyl phthalate, castor oil, and ethyl acetate in addition to the acid-treated cells and resins when preparing cell beads. It is preferable to use these additives 0.05 to 5 times by weight with respect to acid-treated cells, especially 0.1 to 2 times. In addition, agglomeration can be suppressed by heat treating the cell beads. The heat treatment conditions are the same as the conditions for improving the water resistance.

When the heavy metal containing medium is treated with the heavy metal adsorbent composition of the present invention, the heavy metal can be removed from the heavy metal containing medium. Here, the heavy metal-containing medium may include environmental liquids and soils containing heavy metals, and more specifically, heavy metal-containing environmental media such as river water, lakes and swamps, sewage, plant drainage, soil, incineration ash recooling water and plating wastewater. Can be mentioned. As a method for treating the heavy metal-containing medium with the composition of the present invention, for example, a method in which the liquid medium is brought into contact with an acid-treated cell immobilized carrier, and more specifically, the liquid medium is added to a column packed with an acid-treated immobilized carrier. The method of letting it pass is mentioned.

By this treatment, the heavy metal in the medium is adsorbed to the acid treated cells in the composition of the present invention, so that the heavy metal is removed from the medium. The adsorbed heavy metals are easily eluted from the acid-treated cells by lowering the pH due to the addition of organic acids and inorganic acids, and by adding chelating agents such as EGTA and EDTA. In addition, the acid-treated cells eluting the heavy metal can be repeatedly used as a heavy metal adsorbent.

In order to remove heavy metals from heavy metal-containing media such as plant drainage and plating wastewater using the heavy metal adsorbent composition of the present invention, the heavy metal including (A) at least one heavy metal adsorption tank containing the heavy metal adsorbent composition and (B) acid-containing tank It is preferable to use an adsorption device. The heavy metal adsorption tank (A) recovers heavy metals by acid treatment after the heavy metal adsorption treatment, and regenerates the heavy metal adsorbent composition to be used continuously.

In an electroplating plant, wastewater containing a high concentration of heavy metals is discharged in the post-plating cleaning process. Since zinc plating contains a high concentration of cyanide, it is oxidatively decomposed in pretreatment. In addition, since hexavalent chromium is used for chromium plating, it is processed by trivalent chromium by the pretreatment. Then, the plating wastewater containing zinc, nickel, chromium, and the like is discharged by adjusting pH to alkaline with caustic soda and then adding a polymer flocculant to coagulation sedimentation (sludge) to remove the insoluble matter. Most of the sludge is passed to the disposal companies and some are reused, but most of them are returned to landfills.

Therefore, if the heavy metal in the waste liquid is removed by treating the wastewater after the pretreatment with the heavy metal adsorbent composition of the present invention, a large amount of sludge is not generated by adding a polymer flocculant. In addition, if the heavy metal can be recovered with high purity using the heavy metal adsorbent composition of the present invention having high adsorption specificity, the lifetime of the final disposal site can be extended and the reuse of resources can be realized.

Therefore, the heavy metal adsorbent composition and the heavy metal adsorption apparatus of the present invention are particularly useful for recovery of heavy metals from plating wastewater.

Example

Next, although an Example is given and this invention is demonstrated in more detail, this invention is not limited to these Examples.

Example 1 (Selection and Identification of Heavy Metal Adsorbents)

(1) Selection of heavy metal adsorbing bacteria

Soil was suspended in physiological saline and allowed to stand, and the supernatant was planted in Brain Heart Infusion Agar medium containing 1 mM heavy metal to select colonies that appeared after 1 day.

(2) Identification of the obtained strain

a. Way

As a first stage bacterial test, cell morphology, gram staining, spore presence, and motility by flagella were observed by an optical microscope (Olympus U-LH1000, Japan). Colony morphology on Brain Heart Infusion Agar (Becton Dickinson, NJ, U.S.A) + agar medium (B. H. I agar) was observed. Tests were conducted for catalase reactions, oxidase reactions, acid / gas production from glucose and oxidation / fermentation of glucose (O / F).

 As a second stage bacterial test, biochemical properties were tested using the API system (bioMerieux, France: http://www.biomerieux.fr/hom_en.htm) according to the measurement method.

In addition, the physiological properties test was conducted as an additional test.

b. result

The results of the first stage test are shown in Table 1.

TABLE 1

Sample Number KRI-02 KRI-03 KRI-04 Culture temperature (℃) 37 37 37 Cell morphology Rod-shaped
(1.0 × 3.0 ～ 5.0㎛) Rod-shaped
(0.8 × 2.0 ～ 4.0㎛) Sphere
(φ0.8 μm) Gram Dyeing + + + Spores + + - motility - + - Colony form Badge: BHI agar
Incubation time: 48 hours
circle
edge
Slightly wavy
Short and flat
Polish
buff Badge: BHI agar
Incubation time: 48 hours
irregular
edge
: Shaped
Short and flat
Matte
buff Badge: BHI agar
Incubation time: 48 hours
circle
Overall: smoothness

Short and flat
Polish
buff Culture temperature 37 ℃ + + + Culture temperature 45 ℃ + + + Catalase + + + Oxidase - - - Acid / Gas Generation
(Glucose) -/- -/- +/- O / F test
(Glucose) -/- -/- + / + Additional test - - Furazolidone susceptibility + Indicating similarity
Taxonomy Bacillus Bacillus Staphylococcus

+: Positive,-: negative, w: weak response

The results of the second stage test and additional tests are shown in Tables 2-4.

Table 2 (KRI-02)

Fermentation presence Control- Glycerol + Erythritol- D-Aribinose- L-Arabinose + Ribose + D-Xylose- L-Xylose- Adonitol- β-methyl-D-xylose- Galactose- Glucose + Fructose + Mannose + Sorboose- Rhamnose- Dulcitol- Inositol- Mannitol + Sorbitol + α-methyl-D-mannose- α-methyl-D-glucose + N-acetylglucosamine- Amigdalin- Arbutin- Esculin + Raised + Cellobiose + Maltose + Lactose- Melibiose- Sucrose + Trepaas- Inulin- Melizetose- Raffinose- Starch- Glycogen + Xylitol- Genthiobiose- D-Turanose- D-Rixos- D-tagatose- D-fucose- D-fucose- D-Arabitol- L-Arabitol- Gluconate- Biochemical properties 2-ketogluconic acid- 5-ketogluconic acid- β-galactosidase- Arginine Dihydrolase- Lysine Decarboxylase- Ornithine Decarboxylase- Citric Acid Availability- H ₂ S Production- Urease- Tryptophan Deaminase- Indole Production- Acetoin Production + Non-Latinase + Nitrate Reduction + Additional test Growth at 50 ° C + Growth in anaerobic conditions- Growth at 10% NaCl + Hyplate Hydrolyzable- Casein hydrolyzable +

Table 3 (KRI-03)

Fermentation presence Control- Glycerol + Erythritol- D-Aribinose- L-Arabinose + Ribose + D-xylose + L-Xylose- Adonitol- β-methyl-D-xylose- Galactose- Glucose + Fructose + Mannose + Sorboose- Rhamnose- Dulcitol- Inositol + Mannitol + Sorbitol + α-methyl-D-mannose- α-methyl-D-glucose + N-acetylglucosamine + Amigdalin- Arbutin + Esculin + Raised + Cellobiose + Maltose + Lactose- Melibiose- Sucrose + Trepaas- Inulin- Melizetose- Raffinose- Starch + Glycogen + Xylitol- Genthiobiose- D-turanose ± D-Rixos- D-tagatose + D-fucose- D-fucose- D-Arabitol- L-Arabitol- Gluconate- Biochemical properties 2-ketogluconic acid- 5-ketogluconic acid- β-galactosidase + Arginine Dihydrolase + Lysine Decarboxylase + Ornithine Decarboxylase- Citric Acid Availability- H ₂ S Production- Urease- Tryptophan Deaminase- Indole Production- Acetoin Production + Non-Latinase- Nitrate Reduction + Additional test Growth at 50 ° C + Growth in anaerobic conditions + Growth at 10% NaCl + Hyplate Hydrolyzable- Casein hydrolyzable +

Table 4 (KRI-04)

Biochemistry Test and Acidification Test Urease + Arginine Dihydrolase- Ornithine Decarboxylase- Esculin hydrolysis- Glucose + Fructose- D-Mannose- D-maltose + Lactose- Trepaas + D-mannitol + Raffinose- Reduction of nitrates to sulfites + Acetoin Production- β-galactosidase- Arginine Arylamidase- Alkali Phosphatase- Pyrrolidonyl arylamidase- Novobiocin Sodium Resistant- Sucrose + N-acetylglucosamine- D-Turanose- L-Arabinose- β-gluronidase + D-Ribose- D-cellobiose-

From the above results, KRI-02 belongs to the genus Bacillus, but did not reach the species specification. Therefore, the bacterium was transferred to Bacillus sp. It was named KRI-02. In addition, KRI-03 was determined to belong to Bacillus rickenformis and named as Bacillus rickenformis KRI-03. Moreover, although KRI-04 belongs to Staphylococcus sp., It did not reach | occur | produce the species. Therefore, the bacterium was isolated from Staphylococcus sp. It was named KRI-04. KRI-02 is FERM BP-8165, KRI-03 is FERM BP-8166, and KRI-04 is FERM BP-8167, respectively. It is deposited at Chome 1-Ban Chuo Dai 6 (Zip: 305-8566): August 21, 2002).

Example 2

KRI-02, KRI-03 and KRI-04 were rinsed after incubation in Brain Heart Infusin medium (Difco) and suspended by the addition of 0.5N hydrochloric acid in 5-fold volume of wet weight. The hydrochloric acid added bacteria were then shaken at 37 ° C. for 2 hours. In addition, Brierley et al. (US Pat. No. 4,992,179) was also examined. That is, bacteria added with 3% sodium hydroxide in 5 times the wet weight were shaken at 50 ° C. or 100 ° C. for 10 minutes. After shaking, each bacteria was washed thoroughly with water and lyophilized. As a result, as shown in Table 5, in the case of acid treatment compared to the case of washing with water (untreated), the weight was reduced by only 20%, but the sodium hydroxide treatment was reduced by more than 50%, especially 100 When treated at ℃ was reduced by more than 60%.

Table 5

conduct Bacterial weight (after freeze drying)
Top: weight
Bottom: weight percent to water wash KRI-02 KRI-03 KRI-04 Untreated 0.653
100 0.257
100 1.313
100 Acid treatment 0.514
78.7 0.246
95.7 0.930
70.8 Sodium hydroxide 50 ℃ 0.266
40.7 0.074
28.8 0.679
51.7 100 ℃ 0.134
20.5 0.039
15.2 0.483
36.8

Example 3 (Measurement of Metal Adsorption)

Lyophilized bacterial powder was dispersed in buffer solution (Tris: 100 mM) to prepare a suspension of 60 mg / mL. 20 μL of a bacterial suspension was added to 1 mL of an aqueous heavy metal solution (CdCl ₂ , CuSO ₄ , ZnCl ₂ , NiCl ₂ ) prepared at 2.4 mM using Tris (10 mM), followed by stirring for 2 hours. After completion of the reaction, the concentration of heavy metal in the supernatant centrifuged was measured using an atomic absorption photometer.

The results are shown in Tables 6-9. The adsorption amount of cadmium and copper was increased by acid treatment in KRI-02, KRI-03 and KRI-04 compared to water washing. The amount of cadmium adsorption also increased in KRI-02, KRI-03 and KRI-04 by sodium hydroxide treatment, but the acid treatment was higher than that of sodium hydroxide treatment. The adsorption amount of zinc and nickel was increased by acid treatment in KRI-02, KRI-03 and KRI-04, but the amount of adsorption was slightly higher in sodium hydroxide treatment (100 ° C). Comparing the adsorption amount of heavy metals by sodium hydroxide treatment at 50 ° C. and 100 ° C., the amount of adsorption increased when treated at 100 ° C. rather than 50 ° C.

Table 6

conduct Cadmium adsorption amount (μmol / g) KRI-02 KRI-03 KRI-04 Untreated 207.6 25.1 232.3 Acid treatment 447.5 371.4 409.9 Sodium hydroxide 50 ℃ 200.8 266.6 244.4 100 ℃ 389.9 346.8 300.7

Table 7

conduct
Copper adsorption amount (μmol / g) KRI-02 KRI-03 KRI-04 Untreated 611.2 206.6 474.3 Acid treatment 723.2 552.5 618.2 1 sodium hydroxide 50 ℃ 464.7 494.6 546.4 100 ℃ 671.3 537.6 591.3

Table 8

conduct Zinc adsorption amount (μmol / g) KRI-02 KRI-03 KRI-04 Untreated 219.5 66.8 366.9 Acid treatment 458.6 385.9 418.6 Sodium hydroxide 50 ℃ 322.2 326.4 381.5 100 ℃ 466.8 390.8 430.1

Table 9

conduct Nickel adsorption amount (μmol / g) KRI-02 KRI-03 KRI-04 Untreated 10.2 42.1 37.1 Acid treatment 392.3 318.5 330.1 Sodium hydroxide 50 ℃ 244.2 293.7 252.1 100 ℃ 407.0 335.7 322.3

Example 4 (adsorption and dissolution test)

Lyophilized bacteria (KRI-02) were dispersed in 100 mM Tris buffer (pH 7.5) to prepare a suspension (60 mg / mL). 20 μL of this bacterial suspension was added to 1 mL of an aqueous solution of heavy metals (CuS0 ₄ , NiCl ₂ ) prepared at 2.4 mM using Tris (10 mM) and stirred for 2 hours (pH 6.0 and pH 7.3, respectively). After completion of the reaction, the mixture was centrifuged and separated into a supernatant (a) and a homogeneous layer. Hydrochloric acid (pH 1.54) was added to the homogeneous layer, followed by stirring for 30 minutes, followed by centrifugation to separate the supernatant (b) and the homogeneous layer. The heavy metal concentration in supernatant (a) and (b) was measured with the atomic absorption photometer, and the adsorption amount and desorption amount were computed. After hydrochloric acid treatment, the homogeneous layer was washed in 100 mM Tris (pH 7.5) to return the pH to neutral, and the adsorption and desorption experiments of heavy metals were repeated (three times). The results are shown in FIGS. 1 and 2. The adsorption amount of the second metal was decreased compared to the first time, but the second and third times showed almost the same adsorption amount. Desorption amount showed a favorable value 90% or more of adsorption amount in case of Cu. In the case of Ni, although the amount of desorption was small at the first time, the second and third times showed almost the same value as the amount of adsorption, and the composition according to the present invention was found to be reusable for both metals.

Example 5

Synthesis of Additive-Containing Cell Beads

PVA and the same amount of KRI-02 and an additive were added to an aqueous solution of polyvinyl alcohol (PVA) (polymerization degree 1500 to 1800, saponification degree 98%) prepared at 10% (w / v), followed by stirring. The suspension prepared in liquid nitrogen was dropped by syringe, and then lyophilized and lyophilized. Teflon powder, castor oil, ethyl acetate and / or dibutyl phthalate were used as additives.

Example 6

Evaluation of Cohesiveness of Additive-Containing Cell Beads

The cohesiveness (stability) of gel beads (0.35 g) was achieved by using 20 mL (pH 7.5) of recooling water in incinerators containing a large amount of alkali and alkaline earth metals compared to heavy metals (cadmium, copper, zinc and nickel). Investigate. After shaking for 12 hours, adhesion and aggregation of the gel were visually observed. As a result, it was confirmed that the cells were aggregated in the non-added cell beads. In the additive-containing cell beads in which teflon powder and dibutyl phthalate were mixed as additives, the effect of inhibiting aggregation was the highest. Moreover, the effect was moderate in castor oil and ethyl acetate.

Example 7

Effect on Agglomeration of Additive Mixing Ratios

Teflon mixed cell beads were synthesized to investigate the effect of aggregation on the mixing ratio (weight ratio) of the additive and KRI-02. As in Example 6, the cohesiveness (stability) of the beads (0.35 g) was examined using 20 mL (pH 7.5) of recooled water. As a result, the beads which did not mix the cells (KRI-02) were aggregated, but it was found that aggregation was suppressed by increasing the component ratio other than PVA (Table 10).

Table 10

Impact on flocculation of the mixing ratio

Teflon One One One 0.2 0.2 0.5 PVA One One One One One One Cell 0 One 2 One 2 2 × ◎  ◎ △ ○  ○

 ○, ◎: No aggregation ×: Agglomeration △: Agglomeration slightly

Example 8

Adsorption Capacity of Teflon-Containing Cell Beads

Teflon-containing cell beads (weight ratio, Teflon: PVA: cells (KPI-02) = 1: 1: 2) were synthesized, followed by an adsorption test on 20 mL (pH 7.5) of recooled water, followed by elution with 20 mL (pH 1.2) of oxalic acid. The test was conducted. This adsorption / regeneration process was repeated to observe changes in adsorption capacity. The adsorption capacity of the first adsorption capacity and the 10th usage frequency were compared. Even after 10 uses, the adsorption capacity of heavy metals (copper and zinc) hardly decreased. In addition, it could be adsorbed and removed with little influence of salts present in high concentrations (Figs. 3 and 4).

Example 9

Effect of Aggregation and Adsorption on Heat Treated Beads

Gel beads in which KRI-02 was mixed (weight ratio, PVA: cells = 1: 2) were synthesized by the above-described method, and heat treatment (180 ° C) was performed for 10 minutes after lyophilization. As described above, the cohesiveness (stability) of the gel beads (0.35 g) was examined with respect to 20 mL (pH 7.5) of recooled water. Further, in order to investigate the change in adsorption capacity by heat treatment, the concentration change of heavy metals (zinc, nickel) and alkaline earth metals (calcium, magnesium) in the recooled water was measured by atomic absorption photometer. When the heat treated and unheated cell beads were compared, the heat treated cell beads were inhibited from agglomeration and did not adhere to the particles. On the other hand, in the case of mild heat treatment, aggregation was confirmed as described above. In addition, it was found from the change in concentration of each metal in the recooled water that there was almost no decrease in adsorption capacity before and after heat treatment (FIGS. 5 and 6).

Example 10

Change of Adsorption Capacity of Heat Treated Beads

After the adsorption test of the above-mentioned heat-treated beads, the beads were separated and 20 mL (pH 1.2) of oxalic acid was added thereto to dissolve the metals. Thereafter, the mixture was washed with Tris (100 mM) and subjected to an adsorption test again. This series of operations (number of uses) was repeated to investigate the adsorption capacity change of the beads accompanying the regeneration. The adsorption capacity of the 1st time and the 10th use time were compared. As a result, the adsorption capacity of heavy metals (copper and zinc) hardly decreased even when the number of uses was 10 times. In addition, it could be adsorbed and removed with little influence of salts present in high concentrations (Figs. 7 and 8).

Example 11

Preparation of Cell Beads by Granulation Method

Powders of KRI-02 and PVA (polymerization degree and saponification degree 98-99%) pulverized to 150 μm or less were mixed in a weight ratio of 2: 1, and the mixed powder was granulated using a centrifugal flow coating device. That is, spherical granules (lactose) were used as nucleus particles (500 µm) and granulated by spraying the mixed powder while spraying an aqueous PVA solution (5%).

The granulated particles were heat dried (70 ° C.), sieved, and fractionated with a diameter of 1.4˜1.7 mm, followed by heat treatment at 180 ° C. for 20 minutes.

Example 12

Evaluation of Water Resistance of Cell Beads by Granulation Method

Cell beads or unheated cell beads (0.35 g) heat-treated at 180 ° C. for 20 minutes were placed in water (20 mL) and shaken for 24 hours. As a result, the unheated cell beads were suspended and collapsed in a few hours after shaking, while the heat-treated cell beads maintained the shape of the particles even after 24 hours. From this, when the heat treatment was performed on the granulated cell beads, it was confirmed that the cells could be stably fixed while maintaining the shape of the particles.

Example 13

Porosity of beads by freezing

The heat-treated cell beads obtained in Example 11 were immersed in water, washed, and then lyophilized by freeze-thawing in a state of sufficiently containing water. Freeze-treated beads (0.5 g) were added to the plating wastewater containing zinc (20 mL) and stirred to investigate the time dependence of zinc concentration from the start of the reaction. As a control, cell beads subjected to heat treatment only were used. As a result, the concentration change of the cell beads plus the freezing operation was larger than that of the control. After 90 minutes, the zinc concentrations in the lyophilized and lyophilized waste liquids were 354.1 μM and 332.8 μM, respectively, which were lower than the control concentration of 381.6 μM. Therefore, by freezing the heat treated cell beads, it is possible to rapidly diffuse the heavy metal in the beads to promote a decrease in the liquid phase concentration.

Example 14

Removal of Heavy Metals by Beads

After immersion in 1N hydrochloric acid, the heat treated cell beads (Example 11) washed with MES buffer (pH 6) were placed in a zinc-containing plating wastewater and stirred. The concentration of zinc (8, 17.5, 25, 35mg / mL) was changed and the concentration of zinc was examined. The results are shown in FIG. The change in the concentration of zinc depends on the amount of cell beads, and the initial gradient of the change in concentration increased as the amount of beads added increased. Therefore, by injecting cell beads into the wastewater containing heavy metals such as zinc, zinc can be removed and can be removed below a drainage criterion (75.6 µM). The cell beads can adsorb and remove harmful heavy metals such as copper, iron, cadmium and nickel in addition to zinc.

Example 15

Play of beads

The heat treated cell beads (Example 11, 0.35 g) were washed with MES buffer (pH 6) and placed in plating waste water (20 mL) containing zinc and iron, followed by stirring. After completion of the adsorption reaction, the cell beads were recovered from the wastewater and placed in 1N hydrochloric acid (20 mL) to desorb heavy metals. Thereafter, it was washed with MES buffer and the wastewater was refreshed again. This series of adsorption and desorption operations were repeated to repeat the regeneration of the beads. Heavy metal concentration was measured by atomic absorption photometer. The relationship between the amount of zinc adsorbed (pH 7) and the number of regenerations is shown in FIG. 10. In each measurement, the initial average concentration was 790 µM for zinc and 458 µM for iron. The average adsorption amount per g of dry weight (cell beads) was 36.2 micromo / g zinc and 4.6 micromo / g iron. The regeneration count was repeated 100 times, but the cell beads remained in shape, and the adsorption amount was almost unchanged. In addition, as a result of examining the desorption amount for adsorption, it was found that the desorption at a ratio of more than 90%. Therefore, the cell beads are durable against sudden changes in pH and can be used repeatedly.

Example 16

Material balance of use (1) -stirrer for drainage treatment in plating factory

Heat-treated cell beads (Example 11, 400 g) were put in a cyan-plated waste water tank (50 L) containing heavy metals and sampled while stirring (rotational speed: 200 rpm) to investigate the concentration change of zinc and iron. Table 11 shows the concentrations of zinc and iron in the cyan-based plating wastewater tank (pH 7.5). As a result, zinc and iron were present at concentrations above the drainage criteria. The heavy metal concentration change when cell beads were added to this wastewater is shown in FIG. From this result, the adsorption amount per 1 g of dry cell beads was determined. As a result, zinc was 53.6 µmol / g and iron was 12.1 µmol / g.

Table 11

heavy metal 2nd reaction water standard zinc 894 76.5 iron 422 179

                              (Unit: μM)

Example 17

(2) -concentration of adsorption-removing metals for drainage treatment in plating plants

Heat-treated cell beads (Example 11, 400 g) were placed in a cyan-plated waste water tank (50 L) in the same manner as in Example 16, and the adsorption and removal of zinc and iron (90 minutes) were performed. It was put in and desorption and regeneration were performed. After regeneration, the beads washed with aqueous sodium hydroxide solution (pH 7) were put back into the plating waste water tank. This adsorption and desorption operation was repeated to attempt heavy metal concentration in hydrochloric acid. The concentration changes of zinc and iron in the cyanide plating wastewater are shown in FIG. 12. As a result, the concentration of heavy metals in the wastewater decreased as adsorption was repeated. The zinc concentration was lower than the drainage threshold (76.5 µM) by six times of desorption and regeneration, while the iron concentration was higher than the drainage threshold (179 µM). Changes in the concentrations of zinc and iron in hydrochloric acid are shown in FIG. 13. As a result, the zinc concentration in hydrochloric acid increased depending on the number of regeneration of cell beads. However, since the concentration of zinc in the wastewater decreases as the adsorption is repeated, the change is small. After 7 regenerations, the zinc concentration was 2.1 times higher. It was desorbed in hydrochloric acid like railroad zinc, but its concentration was lower and not concentrated compared to zinc. The concentration of zinc to iron was 2.0 in waste water and 7.8 in hydrochloric acid from which heavy metals were desorbed (after 7 times of desorption), and zinc was accumulated at a higher concentration than iron by the use of beads.

Example 18

Use-several times adsorption to drainage treatment in plating factory

Heat-treated cell beads (Example 11, 400 g) were put into a cyan-plated waste water tank, and zinc was adsorbed and removed (90 minutes) (Article 1). After desorption and regeneration in hydrochloric acid (20 L), the solution was washed with aqueous sodium hydroxide solution (pH 7) and placed in a plating waste water tank (Article 2). Adsorption and desorption operations were repeated using a total of five plating waste water tanks (50 L). In each waste water tank, the adsorption amount of zinc after 90 minutes is shown in FIG. As a result, the reproducibility of adsorption was good, and the average adsorption amount was 31.1 µmol / g. In addition, the change of zinc concentration in hydrochloric acid by desorption was investigated (FIG. 15). The concentration of zinc increased depending on the number of regeneration, indicating linearity. Therefore, it is possible to concentrate zinc in a desorption tank by continuously putting cell beads (sorption several times) into a waste water tank and a desorption tank (hydrochloric acid).

Example 19

Construction of heavy metal removal system in wastewater using cell beads.

The heavy metal removal system in the wastewater described in FIG. 16 can be constructed. A wastewater containing a high concentration of heavy metals is placed in the leftmost adsorption tank 1, and after reaction with the cell beads for a certain time, it is sequentially moved to the right adsorption tank, and discharged when the rightmost adsorption tank is finished. The cell beads are sequentially moved from the rightmost adsorption tank to the left, and when the leftmost adsorption tank is completed, the heavy metal adsorbed is desorbed and regenerated by acid treatment. The reproduced cell beads move to the rightmost jaw again and to the left jaw. By using the amount of cell beads according to the concentration of heavy metals in the wastewater, the concentration of heavy metals in the wastewater can be lower than the environmental standard through at least three treatment tanks. The treatment time is preferably at least 1 hour. The hydrochloric acid used for the regeneration treatment is replaced with fresh hydrochloric acid when the heavy metal concentration is high.

Example 20

The heavy metal removal system described in FIG. 17 can be constructed.

Unlike in the case of FIG. 16, the heavy metal in the wastewater is removed by transferring the wastewater without moving the cell beads from the tank. That is, as shown in Fig. 18, when the amount of cell beads according to the concentration of heavy metals in the wastewater is used, wastewater containing heavy metals of high concentration is added to tank 1 → 2 → l, tank 2 → 1 → 2, tank 3 → 4 → 3 The cell beads, which are transferred to the tank 4 → 3 → 4 and are treated with high concentration of wastewater, can be treated with acid and regenerated, thereby continuously treating the wastewater. The hydrochloric acid used for the regeneration treatment is replaced with fresh hydrochloric acid when the heavy metal concentration is high.

By using the heavy metal adsorbent composition of the present invention, it is possible to efficiently remove harmful heavy metals from rivers, lakes and swamps, and plant drainage.

Claims (16)

Bacillus sp. (Bacillus sp.) KRI -02 (FERM BP-8165), Bacillus Lee Kenny formate miss (Bacillus licheniformis) KRI-03 ( FERM BP-8166) and Staphylococcus sp. (Staphylococcus sp.) KRI -04 A heavy metal adsorbent composition containing a cell obtained by acid treatment of a bacterium selected from (FERM BP-8167) with an acid aqueous solution of pH -0.5-2. delete The method of claim 1, A heavy metal adsorbent composition in which an electric acid treated cell is supported on an inorganic carrier or a resin carrier. The method of claim 1, A heavy metal adsorbent composition wherein the electric acid treated cells are cell beads supported on an inorganic carrier or a resin carrier. The method of claim 4, wherein The heavy cell adsorbent composition wherein the electric cell beads comprise Teflon powder, dibutyl phthalate, castor oil or ethyl acetate in addition to the carrier. The method of claim 4, wherein The heavy metal adsorbent composition in which the electric cell beads are obtained by a granulation method. The heavy metal-containing media was Bacillus sp. ( Bcillus sp. ) KRI-02 (FERM BP-8165), Bacillus licheniformis KRI-03 (FERM BP-8166), Staphylococcus sp. ) A method for removing heavy metals from a heavy metal-containing medium, characterized in that the cells selected from KRI-04 (FERM BP-8167) are treated with a heavy metal adsorbent composition containing the cells obtained by acid treatment with an acid aqueous solution of pH -0.5-2. . delete The method of claim 7, wherein A heavy metal removal method, characterized in that the heavy metal-containing medium is selected from environmental liquids and soils containing heavy metals. The method according to claim 7 or 9, A method for removing heavy metals, characterized in that the electric acid treated cells are supported on an inorganic carrier or a resin carrier. The method according to claim 7 or 9, A method for removing heavy metals, characterized in that the acid-treated cells are cell beads supported on an inorganic carrier or a resin carrier. The method of claim 11, A method for removing heavy metals, characterized in that the cells in the cells comprise Teflon powder, dibutyl phthalate, castor oil or ethyl acetate in addition to the carrier. The method of claim 11, The heavy metal removal method, characterized in that the cells are obtained by the granulation method. Bacillus sp. (Bacillus sp.) KRI -02 (FERM BP-8165), Bacillus Lee Kenny formate miss (Bacillus licheniformis) KRI-03 ( FERM BP-8166) and Staphylococcus sp. (Staphylococcus sp.) KRI -04 (FERM BP-8167). (A) At least one heavy metal adsorption tank containing the heavy metal adsorbent composition as described in any one of Claims 1, 3, 4, 5, or 6, and (B) an acid containing tank characterized by the above-mentioned. Heavy metal adsorption device. The method of claim 15, The heavy metal adsorption apparatus characterized by the above-mentioned (A) heavy metal adsorption tank being used after heavy metal adsorption treatment, the recovery of heavy metal by acid treatment, and regeneration of a heavy metal adsorption agent composition.

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