JP3175762B2 - Method and apparatus for removing heavy metals in aquatic polymer and aquatic polymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for removing heavy metals from a marine polymer, and to a marine polymer, and more particularly to a method for removing heavy metals contained in marine polymer such as shellfish and squid which are marine products. Eluted in acidic solution and removed,
The present invention relates to a method and an apparatus for removing heavy metals in a water-producing polymer, which reduce the heavy metals to a level usable as a fertilizer or feed material, and a water-producing polymer.

[0002]

2. Description of the Related Art Water-producing products such as gills of fish and squid, liver and kidney, and midgut glands called uro of shellfish, so-called aquatic macromolecules include heavy metals such as silver, copper, cadmium and zinc. Is concentrated and contained. The concentration of heavy metals contained varies depending on the type of marine products, body organs, season, and habitat.

[0003] For example, cadmium (Cd) contained in a marine polymer of shellfish increases from summer to autumn when the temperature is high, and is 30 to 100 m / kg of dry solid weight.
g or more in many cases. In addition, even in the low temperature period in winter when the concentration is low, several tens of mg are contained. For this reason, conventionally, the marine polymer of the marine product has been disposed of by burying it in the ground, dumping into the ocean, or burning it.

[0004] However, since the aquatic polymer contains a high concentration of proteins and fats, the concentration of heavy metals should be 10 mg or less, preferably 5 m / kg of dry solid weight.
If it can be reduced to g or less, it can be effectively used as a fertilizer or feed material. Conventionally, as a method for removing heavy metals from a marine polymer, Japanese Patent Application No. 6-234846 and Japanese Patent Application No.
It is published in, for example, Japanese Patent No. -203636, and elutes heavy metals contained in aquatic polymer into an acidic solution such as a sulfuric acid solution, and further electrolytically removes heavy metals contained in the acidic solution.

[0005]

However, in the conventional method for removing heavy metals in aquatic polymer described in Japanese Patent Application No. 6-234846, the cadmium content is 5 mg / mg.
There is a drawback that the processing time to make the dry solid weight kg takes several tens of hours or more, which takes a long time. Further, even when the electrolysis operation described in Japanese Patent Application No. 7-203036 is used in combination, a processing time of about 24 hours is required.

[0006] Further, since aquatic polymer is liable to decay and cannot be stored, if tens of tons of aquatic polymer is to be treated in one day, treatment equipment including a transport device and a storage tank is required. Has the drawback that it becomes extremely large and the initial cost is high. In addition, the conventional method for removing heavy metals in aquatic polymer is difficult to remove acidic solution because the acidic solution is liable to be contaminated by components constituting living organisms such as low molecular weight proteins and fats eluted from the aquatic polymer. , Which has the disadvantage of increasing running costs.

The present invention has been made in view of such circumstances, and in removing heavy metals from the aquatic polymer, the treatment time can be significantly reduced, and the aquatic polymer after removal of the heavy metal can be used as a fertilizer or a fertilizer. It is an object of the present invention to provide a method and an apparatus for removing heavy metals in a water-producing polymer, which can be effectively used as a feed, and further reduce the initial cost and running cost, and a water-producing polymer.

[0008]

In order to achieve the above-mentioned object, the present invention provides a water-producing polymer containing a heavy metal,
A water producing body that removes heavy metals in the water producing polymer by an elution step of suspending the heavy metal in the water producing polymer in the acidic solution by suspending in an acidic solution containing at least one selected from hydrochloric acid; In the method for removing heavy metals in a polymer, as a pre-treatment of the elution step, a denaturing step of denaturing a protein in the aquatic polymer, the crude fat content in the aquatic polymer is reduced to 15% by dry solid weight.
A degreasing step of degreasing below, a dehydration / drying step of reducing the water content of the aquatic polymer to 16% or less per dry solid weight,
Characterized in that at least one of the steps is performed.

In order to achieve the above object, the present invention provides a method in which a water-containing polymer containing a heavy metal is suspended in an acidic solution containing at least one selected from sulfuric acid and hydrochloric acid. An elution device for eluting heavy metals in the acidic solution, in the heavy metal removal device in the aquatic polymer removing the heavy metals in the aquatic polymer,
As a pretreatment device of the elution device, a denaturing device for denaturing the protein of the aquatic polymer, a degreasing device for reducing crude fat contained in the aquatic polymer, and reducing a water content of the aquatic polymer. Wherein at least one of the dehydrating / drying devices is provided.

[0010] In order to achieve the above object, the present invention provides a denaturing step of denaturing a protein of an aquatic macromolecule containing a heavy metal, comprising the steps of: A pretreatment step of performing at least one of the following steps: a degreasing step of degreasing to 15% or less; a dehydration / drying step of setting the water content of the aquatic polymer to 16% or less per dry solid weight. An elution step of suspending the aquatic polymer in an acidic solution containing at least one selected from sulfuric acid and hydrochloric acid to elute heavy metals in the aquatic polymer into the acidic solution; and The acidic solution in which the heavy metal is eluted is supplied between the electrodes to which a DC voltage is applied, and an electrolysis step of depositing the ionized heavy metal on the electrode, and the aquatic polymer suspended in the acidic solution is centrifuged. A centrifugal separation step of separating from the acidic solution by law, heavy metal content of marine biological polymer obtained by dry solid weight 1kg per 10m
g or less.

According to the present invention, as a pretreatment of the elution step, a denaturation step of denaturing the protein of the aquatic polymer is performed to coagulate the protein and increase the hydrophobicity. Heavy metals are easily eluted into the acidic solution. In addition, by performing a degreasing step of degreasing the crude fat content of the aquatic polymer to 15% or less per dry solid weight, heavy metals bound to fat can be removed, and in the elution step, Heavy metals are easily eluted into the acidic solution. By further defatting, the water-producing polymer becomes easy to be finely divided, so that the handling becomes easy. In addition, by performing a dehydration / drying step in which the water content of the aquatic polymer is reduced to 16% or less per dry solid weight, the charge on the protein surface is neutralized. In the acidic solution can be increased.

Further, as a pretreatment, a denaturation step, a degreasing step,
By performing the dehydration and drying steps, the preservability of the aquatic macromolecules is significantly improved.For example, preserving the aquatic macromolecules of shellfish harvested in winter and removing heavy metals during summertime You can also. Therefore, by performing at least one of a denaturation step, a degreasing step, and a dehydration / drying step as a pretreatment of the elution step, it is possible to easily remove heavy metals from the aquatic polymer and to greatly reduce the treatment time.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a method and an apparatus for removing heavy metals in a marine polymer according to the present invention and a marine polymer according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a process diagram showing the steps of the method for removing heavy metals in aquatic polymer according to the present invention.

The process of the present invention for removing heavy metals from a marine polymer is mainly composed of a denaturation step of denaturing a protein of the marine polymer and a crude fat content contained in the marine polymer by a dry solid weight. A degreasing step of degreasing to 15% or less, and a water content of the aquatic polymer of 16% per dry solid weight.
The following dehydration and drying steps, and the aquatic polymer is sulfuric acid,
An elution step of suspending the acidic solution containing at least one selected from hydrochloric acid to elute the heavy metals in the aquatic polymer into the acidic solution, and applying the direct current voltage to the acidic solution in which the heavy metals are eluted in the elution step. It consists of an electrolysis step of supplying between the applied electrodes and depositing ionized heavy metal on the electrodes, and a centrifugation step of separating the aquatic polymer suspended in the acid solution from the acid solution by a centrifugation method. The specific device configuration will be described below.

As shown in FIG. 1, a frozen aquatic polymer 12 transported by a transportation means such as a truck 10 is put into a primary storage tank 14 and thawed in a saline solution. By thawing with saline, the water-producing polymer 12 in the primary storage tank 14 is
To prevent deterioration and decay of the product. Thawed aquatic polymer 1
2 is a heater 18 by the conveyor 16 of the primary storage tank 14.
Quantitative delivery. The heater 18 is heated using steam from the steam pipe 20 as a heat source, and the water-producing polymer 12 charged into the heater 18 from the inlet of the heater 18 is heated while being conveyed by the screw conveyor 22. This heater 1
At 8, the protein in the aquatic polymer 12 is denatured and insolubilized. The degree of this denaturation depends on the marine polymer 1
2 was immersed in a 1% sulfuric acid solution for 10 minutes, and then
The amount of solids when collected by centrifugal force for
At 0%, the aquatic polymer 12 is immersed in a 1% sulfuric acid solution for 2 hours, and then subjected to centrifugal force at 1000 G for 3 minutes so that the solid content is at least 80% or more. is necessary. That is, when the water-soluble polymer 12 is immersed in the sulfuric acid solution and then centrifuged to collect solids from the sulfuric acid suspension, the more solids to be recovered, the more solids are not dissolved in the sulfuric acid solution. It can be said that the degree of denaturation is large.

By denaturing the protein of the aquatic macromolecule 12 before the elution step, elution of heavy metals from the aquatic macromolecule 12 into the sulfuric acid solution in the elution step is promoted. This is because, for example, proteins such as fish, squid, and shellfish internal organs form a higher-order structure by binding amino acids, and heavy metals are contained in the higher-order structure of the protein as metallothionein having a cluster structure. Has been captured. Therefore, even if the protein is immersed in the acidic solution as it is, heavy metals are hardly eluted. However, by denaturing the protein, the higher-order structure is destroyed, and heavy metals are easily eluted into the sulfuric acid solution. A simple method of denaturation is heat treatment.In addition to promoting the elution of heavy metals due to protein denaturation, biological fluids and proteins are coagulated, so that handling properties in the subsequent steps are improved, and spoilage bacteria and the like are reduced, and odors are reduced. Is suppressed. The heating temperature is preferably in a temperature range that kills various bacteria but minimizes protein alteration, usually from 60 to 90 ° C. for 30 minutes, and in a short time, by steam heating at 120 ° C.

Next, the aquatic polymer 12 modified by the heater 18 is passed through the screw press machine 2 from the outlet of the heater 18.
4 The marine polymer 12 is squeezed and degreased by a screw press 24 and crushed into granules. The defatted granular water-producing polymer 12 is charged into a defatted cake tank 26. At this time, the product temperature of the aquatic polymer 12 is preferably maintained at 60 ° C. or higher. Then, the defatted crude fat (here, the crude fat means an oil extracted with ethyl ether or hexane)
Content of 15% per dry solid of aquatic polymer 12
Make sure that: As described above, by defatting the crude fat content of the aquatic polymer 12 before the elution step, the elution of heavy metals from the aquatic polymer 12 to the sulfuric acid solution in the elution step is promoted. This is because the crude fat inhibits the permeation of the sulfuric acid solution into the water-producing polymer in the elution step, but the sulfuric acid solution is turned off by the defatting.
This is because it easily penetrates inside. In addition, a heavy metal is bonded to the carboxy group of the fatty acid constituting the fat, and the heavy metal is removed from the aquatic polymer 12 by defatting. In particular, in the removal of cadmium in the aquatic polymer 12, the cadmium concentration in the aquatic polymer 12 is reduced to 20 mg.
When the amount of crude fat is slightly increased, the effect on the dissolution rate is small, but when the amount is reduced to 20 mg / kg
When the amount of crude fat is large when reducing from dry solids to 5 mg / kg or less dry solids, it becomes difficult to significantly reduce the amount. Also, when the aquatic polymer 12 from which heavy metals have been removed is made into a dry powder, if the amount of crude fat is large, it becomes difficult to produce a fine powder having good fluidity.

When degreased, it is difficult to degrease after immersion of the aquatic polymer 12 in a sulfuric acid solution, and it is easy to degrease by preheating or pressing to apply a shearing force under heating. Therefore, it is necessary to perform as a pretreatment of the elution step. As for the degree of degreasing, in the case of using a Soxhlet extractor to measure fats and oils using ethyl ether as a solvent, the elution of heavy metals to the sulfuric acid solution can be rapidly performed by setting the amount to 15% or less per dry solid weight. I can do it. However, when normal hexane is used as the solvent, the concentration may be about 22% or less per dry solid weight. In addition,
Depending on the application, the degree of degreasing needs to be changed. For example, in order to preserve the aquatic polymer 12 from which heavy metals have been removed and use it as a raw material for feeds or the like, it is preferable to reduce the crude fat content to 10% or less per dry solid weight by a measurement method using ethyl ether as a solvent.

As means for degreasing, water-soluble polymer 1
2 is squeezed efficiently with a screw press 24 that can be heated to 80 ° C. or higher, or when a protein is denatured by heating at 90 ° C. for 30 minutes in a cooker in front of the screw press 24 to denature the protein. be able to. In the screw press machine 24, the water content in the water-producing polymer 12 is also about 10%.
% Or more. Also, as another means for degreasing,
When the aquatic polymer 12 is crushed with a cutter and treated with a centrifuge at a GT value of 40,000 m / sec or more, solids, water and oil can be separated.

Next, the granular water-producing polymer 12 is charged into the vacuum dryer 28 from the defatted cake tank 26. The vacuum dryer 28 is heated by the heater 30,
The internal pressure is reduced by the vacuum pump 32. This allows
The water of the aquatic polymer 12 is dehydrated and dried. The water content of the water-producing polymer 12 after dehydration and drying is 16
% Or less. If the water content is 16% or less, the water-producing polymer 12 becomes brittle and powdery. As described above, by dehydrating and drying the water-producing polymer 12 before the elution step, the elution of heavy metals from the water-producing polymer 12 to the sulfuric acid solution in the elution step is promoted. This is because, when suspended in a sulfuric acid solution, the water-producing polymer 12 that has been dehydrated and dried to reduce the water content is depleted of water molecules hydrated on the protein surface and the charge on the protein surface is neutralized. Therefore, the contact with the sulfuric acid solution is facilitated. Furthermore,
This is because the dehydrated and dried aquatic polymer 12 has improved permeability of the sulfuric acid solution and promotes elution of heavy metals. Dehydrated and dried products have better sedimentation than non-dried ones and are easier to separate by centrifugation.Also, the dissolution of components other than heavy metals in the sulfuric acid solution is reduced, so that the recovery rate of sulfuric acid is reduced. improves. In addition, by dehydration and drying, deterioration of protein is suppressed, oxidation of fat is suppressed, and long-term storage is possible, so that the amount of work in the post-process can be leveled.

The water producing polymer 12 dehydrated and dried by the vacuum dryer 28 is stored in a raw material powder tank 34. Since the water-producing polymer having a water content of 16% or less has improved preservability, the water-producing polymer can be stored in the raw material powder tank 34 for a long time without flowing the water-producing polymer continuously to the next step. Aquatic polymer 12 discharged from the bottom of raw material powder tank 34
Is supplied to a mixer 36 and mixed with water supplied from a water pipe 38 in a slurry state. The slurry-like water-producing polymer 12 is supplied to a dissolution inner tank 44 of an acid dissolution tank 42 through a slurry pipe 40. The acid dissolving tank 42 is formed in a double structure of an inner dissolving tank 44 and an outer dissolving tank 46.
Sulfuric acid is added. In this case, the slurry is adjusted so that the water-producing polymer 12 is suspended at a concentration of 50% by weight or less in the sulfuric acid solution. And the marine polymer 12
Is immersed in an acidic solution having a pH of 2.5 or less in the acid dissolving tank 42 to elute heavy metals in the aquatic polymer 12 as metal ions into the sulfuric acid solution. The sulfuric acid solution containing the heavy metal eluted from the aquatic polymer 12 is passed through the solution pipe 50 to the electrolytic cell 5 of the electrolytic tank 52.
4 is sent.

The electrolysis tank 52 includes an electrolysis cell 54 and an outer electrolysis tank 56 for storing the overflow liquid from the electrolysis cell 54. In the electrolysis cell 54, a pair of an anode and a cathode of a DC power supply 58 are connected. Electrodes 57, 57 are provided.
The sulfuric acid solution fed to the electrolytic cell 54 functions as an electrolytic solution, and the concentration of the electrolytic solution is preferably about 1%. Then, air bubbles are blown out from the lower part of the electrolysis cell 54 to perform electrolysis with a constant current or a constant voltage while stirring the sulfuric acid solution.
The sulfuric acid solution from which the heavy metal has overflowed from the electrolytic cell 54 to the outer electrolytic tank 56 is returned to the return pipe 60 and the return pump 6.
2 and is returned to the acid dissolution tank 42. in this way,
When metal ions eluted in the sulfuric acid solution are continuously removed from the liquid by an electrolytic method, the rate at which heavy metals elute from the aquatic polymer 12 is accelerated. At this time, the sulfuric acid suspension of the water-producing polymer 12 in the acid dissolving tank 42 is directly supplied to the electrolytic cell 54, and a DC voltage is applied while stirring with bubbles, or the solid content of the sulfuric acid suspension is removed from the sulfuric acid suspension. It is also possible to remove metal ions by a circulation method in which the supernatant liquid excluding a part is fed to the electrolytic cell 54 to deposit heavy metals on the cathode, and then returned to the acid dissolving tank 42 again.

After performing a heavy metal removing operation by elution and electrolysis in the acid dissolving tank 42 and the electrolytic tank 52 for a predetermined time, the sulfuric acid suspension from which the heavy metals have been removed in the acid dissolving tank 42 is
The water is fed to a centrifugal separator 66 through a discharge pipe 64, and is centrifuged into a concentrated slurry-like aquatic polymer 12 and a sulfuric acid solution. As a method for recovering the aquatic polymer 12 from the sulfuric acid suspension, a separation method utilizing centrifugal force is most preferable. The high-concentration protein-containing liquid is sticky, and the filtration method makes it difficult to separate from the sulfuric acid solution because protein components adhere to the filter medium.

Next, the separated sulfuric acid solution is supplied to an acid pipe 6
8 and returned to the acid dissolution tank 42,
2 is supplied to a neutralization tank 72 via a pipe 70. In the neutralization tank 72, alkali such as caustic soda and calcium oxide is added from an alkali pipe 74,
And the sulfuric acid remaining in the aquatic polymer 12 is neutralized. The neutralized aquatic polymer 12 is supplied to a pipe 78
Through the vacuum dryer 80 to be dried. The dried aquatic polymer 12 is stored in a storage tank 82. In this case, if it is frozen and frozen, it can be stored for a long time.

In the present embodiment, an example in which all of the denaturation step, the degreasing step, and the dehydration / drying step are provided as the pretreatment of the elution step has been described. One of the steps may be performed.

[0026]

EXAMPLES Examples of the present invention, which are carried out by the method for removing heavy metals in a polymer of aquatic product according to the present invention, will be described below. (Example 1) Example 1 is an example in which heavy metals contained in the midgut gland (hereinafter referred to as "uro") of the scallop are removed along the process of FIG.

[0027] Primary storage tank 1 for frozen sea urchin 12
4 and thawed in saline solution;
After heating for 30 minutes, the crushed and degreased uro 12 is stored in a degreased cake tank 26 by squeezing with a screw press 24 while maintaining the temperature at 60 ° C. or more. The crude fat ratio at this time was 9 to 10%. Next, the powder was dried by a vacuum dryer 28 to obtain a powder having a water content of 4% and a mesh size of 30% or less. This was stored in the raw material powder tank 34.

The raw material powder is converted into a water slurry by a mixer 36 having a water pipe 38 and sent to an acid dissolving tank 42.
Heavy metals in uro 12 are eluted into the sulfuric acid solution. At this time, in the electrolytic tank 52, heavy metals such as cadmium, zinc and copper dissolved in the sulfuric acid solution were deposited on the cathode by electrolysis at a constant current density of 1.5 A / dm ³ . This acid dissolution tank 42
And the heavy metal removal operation in the electrolytic tank 52 was performed for 8 hours.
As a result, the cadmium concentration in Uro 12 became 5 mg / kg of dry solids or less.

After the heavy metal removal operation, the sulfuric acid suspension in which the uro 12 is suspended is centrifuged 66 to neutralize the sulfuric acid remaining in the uro 12 separated from the sulfuric acid suspension in a neutralization tank 72. It was dried in a vacuum dryer 80. The recovery rate of the uro after the treatment with respect to the uro raw material was about 90%. (Embodiment 2) Embodiment 2 is a modification in which the apparatus used in the process of FIG. 1 is partially changed.

1 kg of squid offal is placed in a hot water bath at 90 ° C. for about 1 kg.
After being immersed for 0 minutes and drained, the mixture was compressed with a screw press while passing steam at about 120 ° C. The compression ratio of the screw is 1 / 3.6. Yellow-brown pressed liquid 0.3k
g of defatted cake, 0.7 kg of cake, was obtained. The water content of the defatted cake was about 70%.
The squeezed liquid obtained at the time of squeezing is centrifuged for 300 centimeters.
When treated with 0 G for 15 seconds, 40 g of solid content, 20 g of oily light specific gravity liquid, and the remaining water were recovered.

The solids recovered by centrifugation were added to the cake, and fibrous meaty solids were crushed with a high-speed cutter.
The crude fat content in the crushed material was about 7% by dry solid weight. The cake is made into a thread form from a multi-hole nozzle plate with a hole diameter of 1.2 mm using a screw feeder, and has a concentration of 1.5.
Extruded into a 2% sulfuric acid solution. The sulfuric acid solution was made to flow upward, and heavy metals were eluted into the sulfuric acid solution while the thread-shaped pressed cake was slowly settled toward the tank bottom so as to oppose the upward flow. Heavy metals eluted in the sulfuric acid solution were deposited and collected on a cathode plate by an electrolytic method.

The cadmium concentration in the squid's gut before the heavy metal removal operation by the elution / electrolysis operation was 52 mg / kg of dry solid content on average, but the cadmium concentration was 7 mg / dry solid content in 6 hours of the elution / electrolysis operation. kg. In addition, the cadmium concentration was reduced to 4 mg / kg of dry solid content in 8 hours of the elution / electrolysis operation. The cake from which heavy metals have been removed is drained by a centrifuge, then neutralized with an alkaline solution and again centrifuged at 3000.
The liquid was separated at G × 60 seconds. The obtained cake had a water content of about 65% and a protein content of 68%, which was almost unchanged from that before the acid treatment. This cake could be mixed with other ingredients and used as feed for fish and animals. Example 3 Scallop uro (midgut gland) 1 kg (solid content 0.25 kg, Cd content 70 mg / dry solid content k)
g, crude fat content 25%) by a high-speed cutter to prepare a test sample. The prepared test sample was pretreated under the following conditions.

Sample No. No. 1 was squeezed and degreased at 90 ° C., vacuum dried while heating with steam, and had a crude fat of 12%, a water content of 10% and a particle size of 3.2 mesh. Sample No. 2
Is squeezed and degreased at 80 ° C. and dried with warm air, and has a crude fat of 14%, a water content of 12%, and a particle size of 3 to 5 mm. Sample N
o. 3 is squeezed and degreased at 70 ° C and air-dried.
The crude fat is 15%, the water content is 15%, and the particle size is 3.2 mesh.

Sample No. No. 4 was pressed and defatted at 60 ° C., and had a crude fat of 20%, a water content of 36% and a particle size of 3.2 mesh. Sample No. Sample No. 5 was prepared by a conventional method without pretreatment, and had a crude fat of 21%, a water content of 42% and a particle size of 5 to 10 mm. To each of the samples, 1.5 kg of water and 33 g of 75% sulfuric acid were added, and after stirring for 30 minutes, heavy metals in the urine were eluted into the sulfuric acid solution while electrolysis was performed. Then, the solid content in the sulfuric acid solution was sampled at predetermined time intervals, and the cadmium content was measured. Electrolysis has a current density of 3 A / d
It was carried out by constant current electrolysis of m ³ . After completion of the electrolysis, the slurry-like sulfuric acid solution was neutralized by adding caustic soda, and dried with a steam dryer to obtain 0.2 kg of dry powder. This dry powder,
The water content was 5% or less, and the protein content was 60%.

Table 1 shows the results of examining the removal rate of cadmium by centrifugation and the handleability of each sample.
The cadmium removal rates shown in Table 1 are obtained after 4 hours of the elution / electrolysis operation.

[0036]

[Table 1] (Remarks) The centrifugation recovery rate is obtained by examining the degree of denaturation described above, and is 100% after immersion in a 1% sulfuric acid solution for 10 minutes.
When the solid content at the time of collection by applying a centrifugal force for 3 minutes at 0 G was set to 100%, the solid content at the time of being collected by applying a centrifugal force of 3 minutes at 1000 G for 3 hours after immersing in a 1% sulfuric acid solution for 2 hours. Preferably, the solids content is at least 80% or more.

The Cd removal rate is a value when the elution / electrolysis time is 4 hours. The handleability is ◎ extremely good, 良好 good, △ normal, × bad. As can be seen from Table 1, Sample 1 has a crude fat of 15% or less, a water content of 16% or less, and a degree of modification of 80% or more.
-Sample 3 showed good results with a cadmium removal rate of 90% or more in all of the short elution and electrolysis times of 4 hours. In addition, since the recovery rate by centrifugation is 90% or more and the degree of denaturation is large, there is almost no elution of the protein into the sulfuric acid solution of the electrolytic cell. Accordingly, the collected sulfuric acid solution was hardly stained, and furthermore, the electrode was hardly stained.

[0038]

As described above, according to the method and apparatus for removing heavy metals in the aquatic polymer of the present invention and the aquatic polymer, as a pretreatment of the elution step, a denaturation step, a degreasing step, a dehydration / drying step is performed. Since at least one of the steps is performed, elution of the heavy metal in the aquatic polymer into the acidic solution can be enhanced.

[0039] Thereby, in removing heavy metals from the aquatic polymer, the treatment time can be greatly reduced, and the aquatic polymer from which the heavy metals have been removed can be effectively used as a fertilizer or feed. Costs and running costs can be reduced. Furthermore, by performing a denaturation step, a degreasing step, and a dehydration / drying step as a pretreatment, the preservability of the aquatic polymer is significantly improved. In addition, heavy metals can be removed in the spare time of summer.

[Brief description of the drawings]

FIG. 1 is a process chart for explaining the steps of the method for removing heavy metals in aquatic polymer of the present invention.

[Explanation of symbols]

 12 ... aquatic polymer 14 ... primary storage tank 18 ... heater 24 ... screw press machine 26 ... degreasing cake tank 28 ... vacuum dryer 34 ... raw material powder tank 36 ... mixer 42 ... acid dissolution tank 52 ... electrolytic tank 66 ... centrifugal Separator 72 ... Neutralization tank 80 ... Vacuum dryer 82 ... Storage tank

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Claims (10)

(57) [Claims] (1) a water-producing polymer containing a heavy metal,
A water producing body that removes heavy metals in the water producing polymer by an elution step of suspending the heavy metal in the water producing polymer in the acidic solution by suspending in an acidic solution containing at least one selected from hydrochloric acid; In the method for removing heavy metals in a polymer, as a pretreatment of the elution step, a denaturing step of denaturing a protein in the aquatic polymer, a crude fat content contained in the aquatic polymer is reduced to 15% by dry solid weight. A degreasing step of degreasing below, the water content of the aquatic polymer being 16% per dry solid weight
A method for removing heavy metals from a marine polymer, which comprises performing at least one of the following dehydration and drying steps: 2. The method according to claim 1, wherein in the elution step, the aquatic polymer is suspended so as to have a concentration of 50% by weight or less with respect to the acidic solution. Method. 3. The method according to claim 1, further comprising the step of: supplying an acidic solution in which the heavy metal has been eluted in the elution step to between the electrodes to which a DC voltage has been applied, so as to deposit ionized heavy metal on the electrode. 3. The method for removing heavy metals from the aquatic polymer according to 1 or 2. 4. The marine product according to any one of claims 1 to 3, wherein in the degreasing step, the aquatic polymer is defatted by pressing, compressing and kneading at a temperature of 60 ° C. or higher. A method for removing heavy metals from biopolymers. 5. The marine product according to claim 1, further comprising a step of separating the aquatic polymer suspended in the acidic solution from the acidic solution by a centrifugal separation method. A method for removing heavy metals from biopolymers. 6. The degree of denaturation in the denaturation step is determined by immersing the aquatic polymer in a 1% sulfuric acid solution for 10 minutes.
When the solid content at the time of collection by applying a centrifugal force at 000 G for 3 minutes is 100%, the aquatic polymer is immersed in a 1% sulfuric acid solution for 2 hours, and then subjected to a centrifugal force at 1000 G for 3 minutes. At least 80% solids when recovered
The method according to any one of claims 1 to 5, wherein
3. The method for removing heavy metals from a marine polymer according to item 2. 7. A water-producing polymer containing a heavy metal, comprising sulfuric acid,
A water producing body that removes heavy metals in the water producing polymer by an elution device that is suspended in an acidic solution containing at least one selected from hydrochloric acid and elutes heavy metals in the water producing polymer into the acidic solution. In the apparatus for removing heavy metals in a polymer, as a pretreatment device for the elution device, a denaturing device for denaturing the protein of the aquatic polymer, a degreasing device for reducing crude fat contained in the aquatic polymer, A dehydration / drying device for reducing the water content of the aquatic polymer, which is provided with at least one of the following devices: a device for removing heavy metals in the aquatic polymer. 8. An electrolytic apparatus comprising: an electrolytic device for supplying an acidic solution from which the heavy metal has been eluted by the elution device to between electrodes to which a DC voltage has been applied, thereby depositing ionized heavy metal on the electrodes. Item 7. An apparatus for removing heavy metals from a marine polymer according to Item 7. 9. The water-producing polymer according to claim 7, further comprising a centrifugal separator for separating the water-producing polymer suspended in the acidic solution from the acidic solution by a centrifugal separation method. Heavy metal removal equipment. 10. A denaturing step of denaturing a protein of the aquatic macromolecule containing heavy metal, a degreasing step of defatting the crude fat contained in the aquatic macromolecule to 15% or less per dry solid weight, A dehydration / drying step of reducing the water content of the aquatic polymer to 16% or less per dry solid weight; a pretreatment step of performing at least one of the respective steps; An elution step in which the heavy metal in the aquatic polymer is eluted into the acidic solution by suspending in an acidic solution containing at least one selected from the group consisting of: Is supplied between the electrodes to which the ionized heavy metal is applied to precipitate the ionized heavy metal on the electrodes, and the aquatic polymer suspended in the acidic solution is separated from the acidic solution by centrifugation. And heart separation step, the heavy metal content of marine biological polymer obtained by,
An aquatic macromolecule characterized by being 10 mg or less per 1 kg of dry solid weight.