JP4291812B2 - Use of γ-polyglutamic acid (γ-PGA, H form), γ-polyglutamate or γ-polyglutamate hydrogel in the removal of heavy metals from water or water systems and dissolution of calcium and / or magnesium scales in water or water systems. - Google Patents

Description

The present invention relates to γ-polyglutamic acid (γ-PGA, H form) and / or γ-polyglutamate (Na ⁺ form, K ⁺ form and / or NH ₄ ⁺ form) and / or γ-polyglutamate hydrogel (γ- For the complete removal of toxic metals from water or aqueous systems using polyglutamate Na ⁺ , K ⁺ and / or NH ₄ ⁺ forms). This removal is accomplished by generating enveloped aggregates consisting of chelate compounds of gamma-PGA, gamma-polyglutamate and / or gamma-polyglutamate hydrogels and toxic heavy metals. The present invention further provides γ-polyglutamic acid (γ-PGA, H form) and / or γ-polyglutamate (Na ⁺ form, K ⁺ form and / or NH ₄ ⁺ form) and / or γ-polyglutamate hydrogel (γ -Prepared from polyglutamate Na ⁺ form, K ⁺ form and / or NH ₄ ⁺ form) as a solubilizer, to remove calcium scale and / or magnesium scale from water or aqueous systems.

Conventionally, ion exchange (see Non-Patent Document 1), precipitation, membrane separation, and the like are used for heavy metal separation. As membrane technology, nanofiltration, ultrafiltration, reverse osmosis and the like are used. Microfiltration membranes containing metal chelating groups have also been used for heavy metal adsorption and separation (see Non-Patent Document 2). Various adsorbents and ion exchangers for capturing metal ions have been reported. Examples of conventional ion exchange groups include amines, sulfonic acid groups, and carboxylic acid groups. AMP) (see Non-Patent Document 5) and the like have been reported in the literature. According to reports, chelate stability with AMP resin is in the order of Cu ²⁺ > Pb ²⁺ > Ni ²⁺ > Ca ²⁺ . Existing ion exchange resins have been widely used to recover heavy metals and to obtain high quality water for reuse.
Sengupta, A.I. K. (Edit), “Ion Exchange Technology”, Technological Publication Co. Inc. Pennsylvania, 1997 Konishi et al., “Binary Metal Ion Sorption During Permeation Through Chelating Porous Membranes”, J. et al. Memr. Sci. 111: 1, 1996 Jyo, A. “Preparation of Phosphoric Acid Resins with Large Cation Exchange Capacities from Macroreticular Polyglycidyl Methacrylate-Co-Divinylbenzene Beads and Their Behavior in Metal Ion Incorporation” Macrorecticular Polyglycidyl Mathacrylate-Co-Divinyl-Benzene Beads and Their Behavior in Uptake of Metal Ions) ", J. et al. Appl. Polym. Sco. 63: 1327, 1997. Ibrakin, N.M. “Novel Cation Exchange Composites Resulting from Polymerization / Cross-linking of Acrylic acid / N-Methylolacrylamide Mixtures with Cellulose”, J. et al. Appl. Polym. Sci. 49: 291, 1993. Maeda, H.C. "Studies on Selective Adsorption Resin XXX, Prep., Preparation of Macroreticular Chelate Resin Containing Aminomethyl Phosphate Group from Methyl Methacrylate / Divinylbenzene Copolymer Beads. of Macrorecticular Chelating Resins Containing Aminomethylphosphoric Acid Groups From Methylmethacrylate / Divinylbenzene Copolymer Beads and their Adsorption Capacity), “J. Appl. Polym. Sci. 33: 1275, 1987.

Use of a porous membrane containing a chelating agent improves mass transfer by convection (Konishi et al., “Binary Metal Ion Sorption During Permeation Through Chelating Porous Membranes), J. Memr. Sci., 111: 1, 1996.) Functionalized membranes have been reported that contain many polymer chains to bind many metals and have improved membrane capture capabilities. (Bhattacharyya et al., “Novel Poly-L-Glutamic Acid Fictionalized Microfiltration Membranes for Sorption of Heavy Metals at High Capacity”, J. Membrane Sciences, 141, 1998, 121-135). Cellulose and its derivatives are the most versatile and inexpensive starting materials. When trying to trap Pb ⁺⁺ ions with a hydration radius of 0.4 nm, a maximum surface scavenging capacity of 34 mg Pb per gram of membrane is obtained for a single Pb ⁺⁺ ion reaction, even if there is only one available site. Required, which corresponds to a membrane with a surface area of 50 m ² / g BET. Therefore, it is clear that the metal absorption capacity is still low from the viewpoint of industrial use.

The removal of toxic heavy metal ions from water supply systems used for drinking water, tap water, entertainment or other industrial use or reuse is an important issue for everyone. In modern life, safety and health are always the most important issues. γ-polyglutamic acid (γ-PGA, H form) and / or one or more γ-polyglutamate (Na ⁺ form, K ⁺ form and / or NH ₄ ⁺ form) and / or one or more γ-polyglutamate hydrogels ( Easy and efficient reliability to remove harmful heavy metals from aqueous system and dissolve calcium scale or magnesium scale by using γ-polyglutamate Na ⁺ form, K ⁺ form and / or NH ₄ ⁺ form) Completed a method. Furthermore, aggregates formed from heavy metals and γ-polyglutamate can be easily separated by pressure filtration, membrane ultrafiltration or other centrifugal separators.

The present invention provides γ-polyglutamic acid (γ-PGA, H form) as a chelating agent for removing heavy metals from water or water systems and / or as a solubilizing agent for removing calcium scale and / or magnesium scale, γ-polyglutamate Na ⁺ form, γ-polyglutamate K ⁺ form and / or γ-polyglutamate NH ₄ ⁺ form and / or cross-linked γ-polyglutamate hydrogel (γ-polyglutamate Na ⁺ form, γ-polyglutamate Use of K ⁺ form and / or γ-polyglutamate NH ₄ ⁺ form).

γ-Polyglutamate is biodegradable and can be obtained from L-glutamic acid by a submerged fermentation process (Ho, Guan-Huei et al., “Bacillus Subtilis var. natto”). Produced γ-polyglutamic acid (γ-PGA) ((-Polyglutamic Acid ((-PGA) Produced by Bacillus subtilis var. Natto)), Structural Characterization, Chemical Properties and Biology Submitted to Biological Functionality, Ministry of Economic Affairs (ROC) (2003-07-27), 2nd International Biotechnology and Medical Innovation Award 2003 Gold Award (a Gold Prize Winner of The Second International Biotechnology and Medical Care Innovation Award 2003), 2003-11-06, ROC; Yoon, SH et al., “Production of Poly-(-Polyglutamic Acid)”, Biotech non-letters, 22: 585-588, 2000.) Figure 1 shows γ-polyglutamic acid (γ-PGA) and γ-polyglutamate (Na ⁺ , K ⁺ , NH4 ⁺ , Ca ^++, shows the molecular structure of the Mg ⁺⁺ form), FIG. 2, 3 and 4 show ^{1 H-NMR, 13 C-} NMR and FT-IR spectra, respectively. Table the analytical data of the spectrum The titration curve is shown in Fig. 5. The titration curve is shown in Fig. 5. γ-polyglutamate is excellent in water absorption and has a good chelating ability and retention ability against harmful heavy metals usually present in water or water. The polyanionic nature of has been studied for use in aggregating positively charged colloids or scales in wastewater systems (Yokai et al., “Bacillus Subti Floculation Properties of (-PGA Produced by Bacillus subtilis), "J. Ferment. Bioeng. 82 (1), 84-87, 1966 and Bhattacharyya et al., “Novel Poly-L-Glutamic Acid Fictionalized Microfiltration Membranes for High Capacity Sorption of Heavy Metals. for Sorption of Heavy Metals at High Capacity), J. Membrane Sciences, 141, 1998, 121-135).

In one embodiment, the present invention provides γ-polyglutamic acid (γ-PGA, as a chelating agent for removing heavy metals from water or aqueous systems and / or as a solubilizer for removing calcium and / or magnesium scales. H form), γ-polyglutamate Na ⁺ form, γ-polyglutamate K ⁺ form, γ-polyglutamate NH ₄ ⁺ form or a mixture thereof.

The present invention further relates to the use of said γ-polyglutamate hydrogel as a chelating agent for removing heavy metals from water or aqueous systems and / or as a solubilizer for removing calcium scale and / or magnesium scale. The polyglutamate hydrogel is composed of γ-polyglutamate Na ⁺ isomer, γ-polyglutamate K ⁺ isomer, γ-polyglutamate NH ₄ ⁺ isomer or a mixture thereof with diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether. , Polyoxyethylene sorbitol polyglycidyl ether, polysorbitol polyglycidyl ether, polyethylene glycol diglycidyl ether or a mixture thereof.

In another embodiment, the present invention relates to gamma-polyglutamic acid (gamma-PGA) as a chelating agent for removing heavy metals from water or aqueous systems and / or as a solubilizer for removing calcium and / or magnesium scales. , H-form), γ-polyglutamate Na ⁺ isomer, γ-polyglutamate K ⁺ isomer, γ-polyglutamate NH ₄ ⁺ isomer or a mixture thereof and γ-polyglutamate hydrogel, Glutamate hydrogel is composed of γ-polyglutamate Na ⁺ form, γ-polyglutamate K ⁺ form, γ-polyglutamate NH ₄ ⁺ form or a mixture thereof with diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether, Polyoxyethylene sorbitol polyglycy Ether, poly sorbitol polyglycidyl ether, relates to the use, characterized in that the crosslinked prepared using polyethylene glycol diglycidyl ether, or mixtures thereof.

The present invention further relates to the use of said γ-polyglutamate hydrogel as a chelating agent for removing heavy metals from water or aqueous systems and / or as a solubilizer for removing calcium scale and / or magnesium scale. A polyglutamate hydrogel is prepared by crosslinking by irradiating a γ-ray or an electron beam to a γ-polyglutamate Na ⁺ form, γ-polyglutamate K ⁺ form, γ-polyglutamate NH ₄ ⁺ form or a mixture thereof. Relates to the use characterized by.

Furthermore, the present invention provides γ-polyglutamic acid (γ-PGA, H form) as a chelating agent for removing heavy metals from water or water systems and / or as a solubilizing agent for removing calcium scale and / or magnesium scale. , Γ-polyglutamate Na ⁺ isomer, γ-polyglutamate K ⁺ isomer, γ-polyglutamate NH ₄ ⁺ isomer or a mixture thereof and a γ-polyglutamate hydrogel, Use characterized by being prepared by crosslinking γ-polyglutamate Na ⁺ form, γ-polyglutamate K ⁺ form, γ-polyglutamate NH ₄ ⁺ form or a mixture thereof by irradiating with γ-ray or electron beam About.

  γ-polyglutamic acid (γ-PGA, H form) is a polymer of glutamic acid having a degree of polymerization of 1000 to 20000, and consists only of γ-peptide bonds between glutamic units. γ-PGA contains a terminal amine and a number of α-carboxylic acid groups. This polymer generally exists in several states, depending on environmental conditions such as pH, ionic strength, and other cationic species: helix, random coil, β-sheet, helix coil transition region and encapsulated aggregates. . Usually, circular dichroism (CD) is used to measure the abundance of the helix as a function of spectral intensity at 222 nm. The helix coil transition occurs from about pH 3-5 in a homogeneous aqueous solution, and γ-polyglutamic acid (γ-PGA) is in an unbound form and is bound when the pH is shifted to 5-7. The transition from the random coil to the encapsulated aggregate forms a coordination complex with a divalent or higher-valent metal ion due to a large-scale structural change from the linear coil of γ-PGA to the encapsulated aggregate. Occurs in some cases.

Adsorption of metal ions to γ-PGA (polyelectrolyte anion) has two possible mechanisms: (A) direct interaction between metal ions and carboxyl sites and (B) electrostatic potential generated by the COO ⁻ group Although it is believed that retention of mobile heavy metal counterions by the field is involved, it is not intended to be bound by any theory. In addition to interactions with carboxyl groups, amide bonds can also provide weak interaction sites. In addition to the conformation structure and ionization of γ-PGA, it is also important to know the type of hydrolyzed metal species present in the aqueous solution. Since a variety of different chemical species are generated, this can result in differences in the ability to adsorb metals. In the present specification, “heavy metal” generally means Pb, Cd, Al, Fe, Cu, Mn, Cr, Zn, Ni, or Se, but is not limited thereto. For a review of metal ion chelation and metal ion-ligand correlations, see Hancock and Martell's excellent review (Hancock, RD and Martel, AE, Metal ion in aqueous solution). There is a ligand design for selective complexation (see Ligand Design for Selective Complexation of Metal Ions in Aqueous Solution) Chem. Rev. 89 (1989), 1875-). The stability constant LogK ₁ (L) of the metal ion-chelate / complexation increases with the acidity of the metal ion (first metal hydrolysis constant, LogK ₁ (OH ⁻ )). LogK ₁ (L) of glutamic acid and Cd ⁺⁺ , Pb ⁺⁺ , Ni ⁺⁺ , Cu ⁺⁺ , and Fe ⁺⁺⁺ is 4.0, 4.5, 5.5, 7.7, and 12, respectively. is there. The corresponding LogK ₁ (OH ⁻ ) is 4.2, 6.3, 4.6, 7.0, and 11, respectively. Since a variety of different chemical species are generated, there can be differences in absorption capacity per mole of total metal ions.

  Furthermore, according to the present invention, the water or aqueous solution system to be treated is usually at pH 5.0 to 8.0.

γ-polyglutamic acid (γ-PGA, H form), γ-polyglutamate (Na ⁺ form, K ⁺ form, NH ₄ ⁺ form) and these γ-polyglutamate hydrogels contain harmful heavy metal ions Pb ⁺⁺ , Cd ⁺⁺ , Al ⁺⁺⁺ , Fe ⁺⁺ , Fe ⁺⁺⁺ , Cu ⁺⁺ , Mn ⁺⁺ , Cr ⁺⁺⁺ , Zn ⁺⁺ , Ni ⁺⁺ , Se ⁺⁺⁺⁺ , powerful and selective binding, It has been shown to produce and precipitate agglomerated chelate compounds that can be easily removed by conventional filtration equipment or membrane filtration systems. Therefore, high-quality drinking water, tap water, and industrial water that do not contain harmful heavy metals can be obtained.

According to the present invention, γ-polyglutamic acid (γ-PGA, H form), γ-polyglutamate (Na ⁺ form, K ⁺ form, NH ₄ ⁺ form) and these γ-polyglutamate hydrogels are calcium salts and magnesium. Reacts with the salt to form water-soluble stable calcium γ-polyglutamate and magnesium γ-polyglutamate, respectively. γ-polyglutamic acid (γ-PGA, H-form), γ-polyglutamate and / or γ-polyglutamate hydrogel dissolves calcium salt scale normally found in water systems such as water pipes, tanks and other treatment devices, Excellent for controlling scale formation of strong calcium / magnesium mixed salts.

Treatment by microfiltration, ultrafiltration, ion exchange or reverse osmosis is insufficient, and toxic heavy metals often remain in drinking water and tap water systems. By using γ-polyglutamate and a hydrogel based on γ-polyglutamate or γ-PGA, the residue of harmful heavy metals can be completely removed by chelation or complexation. Heavy metal ions Pb ⁺⁺ , Cd ⁺⁺ , Al ⁺⁺⁺ , Fe ⁺⁺ , Fe ⁺⁺⁺ , Cu ⁺⁺ , Mn ⁺⁺ , Cr ⁺⁺⁺ , Zn ⁺⁺ , Ni ⁺⁺ , Se ⁺⁺⁺⁺ As soon as is chelated, the γ-polyglutamate molecule changes its structure from an open linear coil to an encapsulated complex by multidentate complexation and binds strongly to the chelated heavy metal ion. Large aggregates then precipitate from the liquid and can be separated from the aqueous phase using any type of filtration system. γ-polyglutamic acid, γ-polyglutamate and / or γ-polyglutamate hydrogels are ideal adsorbents that produce drinking water and tap water that do not contain heavy metal ions by completely removing harmful heavy metal ions from water or water systems It is.

  γ-polyglutamic acid (γ-PGA, H form) contains a number of carboxy pendant groups as sites for binding a number of metals. γ-polyglutamic acid (γ-PGA, H form) exists in at least five different structural states depending on the surrounding environmental conditions. That is, at low pH, α-helix (Zanuy, D. et al., “On the Helical Conformation of Un-Ionized Poly-((-D -Glutamic Acid)) ", International Journal of Biological Macromolecules 23 (1998), 175-184), β-sheet, neutral pH in the envelope of microbial cells Nearby are linear coils, encapsulated aggregates when bound to certain metal ions, helix-random coil transition states (Holtzer A. et al., “Helical poly (L-glutamic acid in salt solution) The State of Aggregation of a Helical-Poly (l-Glutamic Acid) in Aqueous Salt Solutions), J. Am. Chem. Soc. 118 (1996), 42 The length of the repeating unit is 0.15 nm in the α-helix structure state and 0.35 nm in the linear random coil structure state, and the translational turn every three residues is The pKa of the side chain α-carboxyl group of γ-polyglutamic acid (γ-PGA, H form) is 4.06.At pH 4.06, the non-ionized α-helix form and There are almost equal amounts of ionized linear coil bodies.

  According to the study by the present inventors, as soon as γ-polyglutamic acid (γ-PGA) chelates heavy metal ions, the structure changes from a linear random coil structure to a highly encapsulated aggregate, and from the liquid layer. Precipitation has shown that toxic metal ions can be removed from the aqueous system.

A commercially available target amount of γ-polyglutamic acid (γ-PGA, H form) and a salt thereof, that is, γ-polyglutamate (Na ⁺ form, K ⁺ form, NH ₄ ⁺ form) are obtained by Bacillus subtilis ( It can be produced using Bacillus subtilis var. Natto, and Bacillus licheniformis (see JP05-316999) as the main feedstock. Can be produced using. The microbial culture medium contains appropriate amounts of carbon source, nitrogen source, various inorganic minerals and other nutrients. Usually, as part of the carbon source, the amount of L-glutamic acid is 3-12%, glucose is used in a concentration range of 5-12%, citric acid is used in a concentration of 0.2-2%, peptone and ammonium sulfate or urea. Is used as a nitrogen source, yeast extract is used as a nutrient source, and Mn ⁺⁺ , Mg ⁺⁺ or NaCl is used as a mineral source. The culture is maintained at 30 to 40 ° C. under appropriate aeration and agitation, and the pH is maintained at 6 to 7.5 using urea solution or sodium hydroxide solution. The culture time is usually 48 to 84 hours. γ-polyglutamic acid (γ-PGA, H form) and salts thereof, that is, γ-polyglutamate (Na ⁺ form, K ⁺ form, NH ₄ ⁺ form) accumulate extracellularly.

γ-polyglutamic acid (γ-PGA, H form) and salts thereof, that is, γ-polyglutamate (Na ⁺ form, K ⁺ form, NH ₄ ⁺ form) are usually extracted from fermentation broth by a series of procedures. In the procedure, cells are separated by ultracentrifugation or pressure filtration, and 3 to 4 times ethanol is added to add γ-polyglutamic acid (γ-PGA, H form) or a salt thereof, that is, γ-polyglutamate (Na ⁺ Body, K ⁺ body, NH ₄ ⁺ body). The precipitate is redissolved in water, and γ-polyglutamic acid (γ-PGA, H form) and its salt, ie, γ-polyglutamate (Na ⁺ form, K ⁺ form, NH ₄ ⁺ form) are newly used using ethanol. To precipitate. This dissolution-precipitation step is repeated several times to recover pure γ-polyglutamic acid (γ-PGA, H form) and its salt, that is, γ-polyglutamate (Na ⁺ form, K ⁺ form, NH ₄ ⁺ form). .

Usually, γ-polyglutamic acid (γ-PGA, H form) and salts thereof, that is, γ-polyglutamate (Na ⁺ form, K ⁺ form, NH ₄ ⁺ form) are used in an appropriate solvent such as water, ethanol or methanol. Dissolve and adjust pH to 5.0-7.5. With constant stirring, an appropriately selected polyfunctional chemical cross-linking agent such as polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether, polyethylene glycol diglycidyl ether, trimethylolpropane triacrylate is added to this solution. The amount added varies depending on the type of crosslinking agent and the quality required for the hydrogel, but γ-polyglutamic acid (γ-PGA, H form) or a salt thereof, that is, γ-polyglutamate (Na ⁺ form, K ⁺ form, NH). ₄ ⁺ body) in the range of 0.01 to 20%. Normally, the gelation reaction is completed in 1 to 4 hours at a reaction temperature of 50 to 120 ° C., although it varies depending on the equipment and conditions used. Next, the produced hydrogel was freeze-dried, and the dried crosslinked γ-polyglutamic acid (γ-PGA, H form) or a salt thereof, that is, γ-polyglutamate hydrogel (Na ⁺ form, K ⁺ form and NH ₄ ⁺ form) (prepared from γ-polyglutamate). It is superabsorbent, non-water soluble and produces a colorless, transparent and biodegradable hydrogel when fully swollen in water.

Γ-polyglutamic acid (γ-PGA, H form) having a molecular weight of 5000 to 900,000 or a salt thereof, that is, γ-polyglutamate (Na ⁺ form, K ⁺ form, NH ₄ ⁺ form) is selected under specific reaction conditions. (PH, temperature, reaction time, γ-polyglutamic acid (γ-PGA, H form) concentration) can be produced by acid hydrolysis controlled. The pH, HCl or H ₂ SO _4, with a suitable acid such as other organic acids (acidulants) can be adjusted PH2.5～6.5. Hydrolysis can be performed in the range of 50 to 100 ° C. The reaction time is 0.5 to 5 hours, and the concentration of γ-polyglutamic acid (γ-PGA, H form) having a molecular weight of 1 × 10 ⁶ or more can be set to any necessary concentration. Select high-purity, low to medium molecular weight γ-polyglutamic acid (γ-PGA, H form) or a salt thereof, that is, γ-polyglutamate (Na ⁺ form, K ⁺ form, NH ₄ ⁺ form) Therefore, after the reaction is completed, further purification and drying by dialysis or membrane filtration are required. The acid hydrolysis rate is faster as the pH is lower, the temperature is higher, and the concentration of γ-polyglutamic acid (γ-PGA, H form) is higher. A γ-polyglutamate salt (Na ⁺ isomer, K ⁺ isomer, NH ₄ ⁺ isomer) is obtained by converting a selected γ-polyglutamic acid (γ-PGA, H isomer) to a selected metal ion (Na ⁺ , K ⁺ , NH _4). ⁺ ) It can be produced by reacting with a basic hydroxide solution or oxide, and the pH can be adjusted to the desired value of 5.0 to 7.2 as required.

  In order to further illustrate the present invention, the following experimental examples are shown to show how the present invention removes toxic metal ions from water and dissolves calcium and / or magnesium derived calcium scales and magnesium scales. However, the scope of the present invention is not limited by these experimental examples.

Experimental example 1
Absorption of Pb ⁺⁺ by γ-polyglutamate (Na ⁺ form) γ-polyglutamic acid (γ-PGA, H form, molecular weight 890 × 10 ³ ) was dissolved in deionized water, and 2% γ-polyglutamate (Na ⁺ Body) Working solution (100 mL) was prepared and the pH was adjusted to 6.0 with 20% NaOH solution. 10 ⁻² MPb (NO ₃ ) ₂ working solution (25 mL) was added to C.I. P. Prepared from grade Pb (NO ₃ ) ₂ . Stepwise prepare solutions with different Pb (NO ₃ ) ₂ concentrations (15 mL each, final concentrations: 0.09, 0.12, 0.17, 0.22, 0.36, 0.45 mmol / L) Add 25 mL of 0.016% γ-polyglutamate (Na ⁺ form) to each Pb (NO ₃ ) ₂ solution, mix well, then adjust the pH to 6.0 with 10% NaOH solution, then add deionized water. The final volume was 50 mL. The mixture was mixed thoroughly and allowed to stand for 30 minutes to complete chelation, and then the precipitate was filtered using an ultrafiltration membrane filtration cartridge (fraction molecular weight: 20000 Dalton) to separate the precipitate. The residual Pb ⁺⁺ ion concentration in the clear filtrate was then measured using an ICP / MS analyzer.

  The results obtained in Experimental Example 1 are shown in Table 2.

From the above results, it was shown that Pb ⁺⁺ ions were chelated by γ-polyglutamate to form stable white precipitates as Pb ⁺⁺ , γ-PGA complex aggregates. The saturated absorption capacity is about 4 mMol. Pb ⁺⁺ per gram of γ-PGA. It is.

Experimental example 2
In γ- polyglutamate (Na ⁺ form) absorption Experimental Example 1 of Cd ⁺⁺ by, Pb (NO _{3) 2} in place of C. P. Grades of Cd (NO ₃ ) ₂ and gradually different Cd (NO ₃ ) ₂ concentrations (final concentrations: 0.09, 0.12, 0.17, 0.21, 0.34, 0 .42 mMol./L) was prepared, and an experiment similar to Experimental Example 1 was performed.

  The results obtained in Experimental Example 2 are shown in Table 3.

From the above results, it was shown that Cd ⁺⁺ ions were chelated by γ-polyglutamate to form stable precipitates as Cd ⁺⁺ , γ-PGA complex aggregates. The saturated absorption capacity is about 3.7 mMol. Cd ⁺⁺ per gram of γ-PGA. It is.

Experimental example 3
In γ- polyglutamate (Na ⁺ form) absorption Experimental Example 1 of Cu ⁺⁺ by, Pb (NO _{3) 2} in place of C. P. Grades of Cu (NO ₃ ) ₂ with different concentrations of Cu (NO ₃ ) _{2 in} stages (final concentrations: 0.08, 0.11, 0.16, 0.20, 0.33, 0 .42 mMol./L) was prepared, and an experiment similar to Experimental Example 1 was performed.

  The results obtained in Experimental Example 3 are shown in Table 4.

From the above results, it was shown that Cu ⁺⁺ ions were chelated by γ-polyglutamate to form a stable blue-green precipitate as Cu ⁺⁺ , γ-PGA complex aggregates. Saturated absorption capacity is about Cu ⁺⁺ about 4.5 mMol per gram of γ-PGA. It is.

Experimental Example 4
In γ- polyglutamate (Na ⁺ form) absorption Experimental Example 1 Fe ⁺⁺ by, Pb (NO _{3) 2} in place of C. P. Grades of Fe (NO ₃ ) ₂ with different concentrations of Fe (NO ₃ ) _{2 in} stages (final concentrations: 0.024, 0.031, 0.045, 0.060, 0.093, 0 126 mMol./L), and the same experiment as in Experiment Example 1 was performed at pH 4.0.

  The results obtained in Experimental Example 4 are shown in Table 5.

From the above results, it was shown that Fe ⁺⁺ ions were chelated by γ-polyglutamate to form a stable yellow precipitate as Fe ⁺⁺ , γ-PGA complex aggregates. The saturated absorption capacity is about Fe ⁺⁺ about 0.5 mMol per gram of γ-PGA. It is.

Experimental Example 5
In γ- polyglutamate (Na ⁺ form) absorption Experimental Example 1 of Al ⁺⁺⁺ by, Pb (NO _{3) 2} in place of C. P. Grades of Al (NO ₃ ) ₃ and solutions with different concentrations of Al (NO ₃ ) _{2 in} stages (final concentrations: 0.041, 0.053, 0.073, 0.092, 0.153, 0 193 mMol./L) and the same experiment as in Experimental Example 1 was performed at pH 4.0.

  The results obtained in Experimental Example 5 are shown in Table 6.

From the above results, it was shown that Al ⁺⁺⁺ ions were chelated by γ-polyglutamate to form a stable white precipitate as Al ⁺⁺⁺ , γ-PGA complex aggregates. The saturated absorption capacity is about 2.0 mMol. Al ⁺⁺⁺ per gram of γ-PGA. It is.

Experimental Example 6
Competitive absorption in a mixture of γ-polyglutamate (Na ⁺ form) and Pb ⁺⁺ , Cd ⁺⁺ , Cu ⁺⁺ P. Grades of Pb (NO ₃ ) ₂ , Cd (NO ₃ ) ₂ and Cu (NO ₃ ) _2, with different concentrations for Pb (NO ₃ ) ₂ , Cd (NO ₃ ) ₂ and Cu (NO ₃ ) ₂ (Final volume: 50 mL) was prepared, and an experiment similar to Experimental Example 1 was performed.

  The results obtained in Experimental Example 6 are shown in Table 7.

From the results of Table 7, it can be seen that at 25 ° C. and pH 6.0, competitive chelation of heavy metal ions by γ-polyglutamate (Na ⁺ form) is in the order of Pb ⁺⁺ > Cu ⁺⁺ > Cd ^++. Indicated. For each of Pb ⁺⁺ , Cd ⁺⁺ , and Cu ⁺⁺ ions, the initial ion concentration was 0.03 mMol. / L to 0.0002, 0.0032, 0.0147 mMol. / L. If γ-polyglutamate (Na ⁺ form) exceeding the saturation amount is used, heavy metal ions Pb ⁺⁺ , Cd ⁺⁺ , and Cu ⁺⁺ can be completely absorbed, and as a result, they can be precipitated as chelate complex aggregates.

Experimental Example 7
Effect of pH on competitive absorption in a mixture of γ-polyglutamate (Na ⁺ form) and Pb ⁺⁺ , Cd ⁺⁺ , Cu ^{++ In} Experimental Example 1, C.I. P. Grades of Pb (NO ₃ ) ₂ , Cd (NO ₃ ) ₂ and Cu (NO ₃ ) _2, with different concentrations for Pb (NO ₃ ) ₂ , Cd (NO ₃ ) ₂ and Cu (NO ₃ ) ₂ (Final volume: 50 mL) was prepared, and an experiment similar to Experimental Example 1 was performed at 25 ° C. and pH 4.28.

  The results obtained in Experimental Example 7 are shown in Table 8.

From the results of Table 8, at 25 ° C. and pH 4.28, competitive chelation of heavy metal ions by γ-polyglutamate (Na ⁺ form) is in the order of Pb ⁺⁺ > Cu ⁺⁺ > Cd ^++. Indicated. For each of Pb ⁺⁺ , Cu ⁺⁺ and Cd ⁺⁺ ions, the initial ion concentration was 0.03 mMol. / L to 0.0026, 0.00265, 0.0312 mMol. / L. Apparently, the lower the pH of the solution, the lower the chelating ability of γ-polyglutamate (Na ⁺ form). For each of Pb ⁺⁺ , Cu ⁺⁺ and Cd ⁺⁺ ions, the chelating ability is 1.52, 1.46, 0.91 mMol. / Adsorption g to 1.45, 0.29, 0.09 mMol. / L. It is considered that the maximum chelating ability of γ-polyglutamate (Na ⁺ form) against Pb ⁺⁺ , Cu ⁺⁺ , and Cd ⁺⁺ ions is in the range of pH 6 to pH 7.5. This corresponds to the pH range in which the (Na ⁺ body) forms a completely open linear random coil structure. If γ-polyglutamate (Na ⁺ form) exceeding the saturation amount is used, heavy metal ions Pb ⁺⁺ , Cd ⁺⁺ , and Cu ⁺⁺ can be completely absorbed, and as a result, they can be precipitated as chelate complex aggregates.

Experimental Example 8
Saturation binding of Pb ⁺⁺ , Cd ⁺⁺ , Cu ⁺⁺ with γ-polyglutamate (Na ⁺ form) in water In Experimental Example 1, C.I. P. An experiment similar to Experimental Example 1 was performed at 25 ° C. using grades of Pb (NO ₃ ) ₂ , Cd (NO ₃ ) ₂ and Cu (NO ₃ ) ₂ , and changing the concentration of γ-polyglutamate (Na ⁺ form). , PH 6.0.

  The results obtained in Experimental Example 8 are shown in Table 9.

From the above results, Pb ⁺⁺ , Cd ⁺⁺ and Cu ⁺⁺ ions are chelated by γ-polyglutamate, and stable white, white and blue-green precipitates as complex aggregates of γ-PGA and metal ions, respectively. Was formed. The saturated absorption capacity is about 2.0 mMol. It is.

(A) γ-polyglutamic acid (γ-PGA, H form), (B) γ-polyglutamate K ⁺ form, γ-polyglutamate Na ⁺ form and γ-polyglutamate NH ₄ ⁺ form, (C) γ-poly Chemical structures of glutamate Ca ⁺⁺ and γ-polyglutamate Mg ⁺⁺ (M (I) = K ⁺ , Na ⁺ , or NH ₄ ⁺ , M (II) = Ca ⁺⁺ or Mg ⁺⁺ ). 400 MHz ¹ H of various (A) γ-polyglutamate Na ⁺ isomers, (B) γ-polyglutamate K ⁺ isomers, and (C) γ-polyglutamate NH ₄ ⁺ isomers in D ₂ O at neutral pH and 30 ° C. -NMR spectrum. Chemical shift is measured in ppm from internal standard. X is an impurity peak. Various (A) γ-polyglutamate K ⁺ isomers, (B) γ-polyglutamate Na ⁺ isomers, (C) γ-polyglutamate Ca ⁺⁺ isomers and (D) in D ₂ O at pH neutral and temperature 30 ° C. ¹³ C-NMR spectrum of γ-polyglutamate Mg ⁺⁺ form. Chemical shift is measured in ppm from internal standard. Infrared (FT-IR) absorption spectra of (C) γ-polyglutamate Ca ⁺⁺ form and (D) γ-polyglutamate Mg ⁺⁺ form by KBr pellets. (A) 10% γ-PGA and 0.2N NaOH, (B) 2% γ-PGA and Ca (OH) ₂ and (C) 4% γ-PGA and 5N NH ₄ OH at 25 ° C. .

Claims (15)

Under conditions of pH 6.0 to 8.0, γ-polyglutamic acid (γ-PGA, H form), γ-polyglutamate Na ⁺ form, γ-polyglutamate K ⁺ form, and γ-polyglutamate under conditions of pH 6.0 to 8.0 A method for removing heavy metals, calcium scale, or magnesium scale from water or an aqueous system, comprising a treatment with NH ₄ ⁺ form or a mixture thereof. The method according to claim 1, wherein the heavy metal is Pb, Cd, Al, Fe, Cu, Mn, Cr, Zn, Ni, or Se. The method according to claim 1, wherein the pH condition is 6.0 to 7.5 . A method for removing heavy metals, calcium scales, or magnesium scales from water or water systems comprising the step of treating the water or water systems with γ-polyglutamate hydrogel under conditions of pH 6.0-8.0. The γ-polyglutamate hydrogel is composed of γ-polyglutamic acid (γ-PGA, H form), γ-polyglutamate Na ⁺ form, γ-polyglutamate K ⁺ form, γ-polyglutamate NH ₄ ⁺ form or a mixture thereof. Prepared by cross-linking with diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether, polyoxyethylene sorbitol polyglycidyl ether, polysorbitol polyglycidyl ether, polyethylene glycol diglycidyl ether or mixtures thereof The way . The method according to claim 4, wherein the heavy metal is Pb, Cd, Al, Fe, Cu, Mn, Cr, Zn, Ni, or Se. The method according to claim 4, wherein the pH condition is 6.0 to 7.5 . Under conditions of pH 6.0 to 8.0, γ-polyglutamic acid (γ-PGA, H form), γ-polyglutamate Na ⁺ form, γ-polyglutamate K ⁺ form, and γ-polyglutamate under conditions of pH 6.0 to 8.0 A method for removing heavy metal, calcium scale, or magnesium scale from water or an aqueous system, comprising a step of treating with a combination of an NH ₄ ⁺ form or a mixture thereof and a γ-polyglutamate hydrogel , wherein the γ− The polyglutamate hydrogel is prepared by converting γ-polyglutamic acid (γ-PGA, H form), γ-polyglutamate Na ⁺ form, γ-polyglutamate K ⁺ form, γ-polyglutamate NH ₄ ⁺ form or a mixture thereof with diglycerol poly Glycidyl ether, polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether, polyoxyethylene sol A method prepared by cross-linking using bitol polyglycidyl ether, polysorbitol polyglycidyl ether, polyethylene glycol diglycidyl ether or a mixture thereof. The method according to claim 7, wherein the heavy metal is Pb, Cd, Al, Fe, Cu, Mn, Cr, Zn, Ni, or Se. The method according to claim 7, wherein the pH condition is 6.0 to 7.5 . A method for removing heavy metals, calcium scales, or magnesium scales from water or water systems comprising the step of treating the water or water systems with γ-polyglutamate hydrogel under conditions of pH 6.0-8.0. The γ-polyglutamate hydrogel is crosslinked by irradiating the γ-polyglutamate Na ⁺ isomer, the γ-polyglutamate K ⁺ isomer, the γ-polyglutamate NH ₄ ⁺ isomer or a mixture thereof with γ rays or an electron beam. Prepared method . The method according to claim 10, wherein the heavy metal is Pb, Cd, Al, Fe, Cu, Mn, Cr, Zn, Ni, or Se. The method according to claim 10, wherein the pH condition is 6.0 to 7.5 . Under conditions of pH 6.0 to 8.0, γ-polyglutamic acid (γ-PGA, H form), γ-polyglutamate Na ⁺ form, γ-polyglutamate K ⁺ form, and γ-polyglutamate under conditions of pH 6.0 to 8.0 A method for removing heavy metal, calcium scale, or magnesium scale from water or an aqueous system, comprising a step of treating with a combination of an NH ₄ ⁺ form or a mixture thereof and a γ-polyglutamate hydrogel , wherein the γ− A polyglutamate hydrogel is prepared by cross-linking by irradiating a γ-polyglutamate Na ⁺ form, a γ-polyglutamate K ⁺ form, a γ-polyglutamate NH ₄ ⁺ form or a mixture thereof with γ rays or an electron beam . Way . The method of claim 13, wherein the heavy metal is Pb, Cd, Al, Fe, Cu, Mn, Cr, Zn, Ni, or Se. The method according to claim 13, wherein the pH condition is 6.0 to 7.5 .