JPH078809A - Waste water treating agent and treatment of waste water - Google Patents

Abstract

PURPOSE:To obtain a waste water treating agent capable of efficiently treatment a waste water containing particularly heavy metals or oil component by using a crystalline silicate compound expressed by a specific general formula as an anhydride and equal or more than the specified value in a cation exchange capacity as a main component. CONSTITUTION:The waste water treating agent is composed of the crystalline silicate compound as an effective component. The crystalline silicate compound is expressed by xM2O.ySiO2M'O as the general formula of the anhydride. The cation exchange capacity is controlled to >=150mg CaCO3/g. In the formula, M are Na and/or K, M' are Ca and/or Mg, (y)/(x) is 0.5-4.0, (z)/(x) is 0-1.0. The crystalline silicate compound having 0.3-3.0ml/g oil absorption ability can be used as the effective component. And the silicate compound is used for the method for treating the waste water containing heavy metal or oil component.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wastewater treatment agent and a wastewater treatment method used for treating wastewater containing various oils such as heavy metals harmful to humans, surfactants causing water pollution of oceans and rivers, and surfactants. .

[0002]

2. Description of the Related Art As a method for removing heavy metals in industrial wastewater, Japanese Patent Laid-Open No. 55-757.
Japanese Patent Laid-Open No. 79 discloses a method in which wastewater containing heavy metals is absorbed by a mineral powder and then shaped and fired. However, since the powder is a natural mineral substance such as kaolin and talc, it has a small ability to capture heavy metal ions in the waste water (ion exchange ability) and requires a large amount of mineral substance, which is preferable in terms of resource saving. Absent. Further, JP-A-53-82049 discloses a method of contacting a fine composite composed of inorganic fine particles mainly composed of minerals montmorillonite and hyrosite and an organic high molecular weight polymer with waste water containing a nonionic surfactant. Is disclosed. However, in this case as well, the ability of the inorganic fine particles themselves to capture the surfactant is poor and a large amount of the treating agent is required, so that the handling of the treating agent after the wastewater treatment becomes a problem. Further, there is a method of using amorphous sodium silicate having a large ion exchange ability, but it is not preferable because recovery after treatment is difficult because it has extremely high solubility in water. Therefore, it has been desired to use a large amount of various oil components such as heavy metal ions and surfactants and to use an inorganic substance having excellent water resistance.

[0003]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that they have a high cation trapping ability and a surfactant trapping ability required for a wastewater treatment agent, and are water resistant. The present invention has been completed by finding a wastewater treatment agent composed of a silicate having excellent properties.

That is, the gist of the present invention is xM ₂ O.ySiO ₂ .zM 'O (wherein M is
Represents Na and / or K, M ′ represents Ca and / or Mg
, Y / x = 0.5 to 4.0, z / x = 0 to 1.0
Is. ), The cation exchange capacity is 150 mgC
aCO ₃ / g or more, or oil absorption capacity of 0.3 to 3.0 m
A wastewater treatment agent comprising a crystalline silicate compound of 1 / g as an active ingredient, and (2) a method for treating wastewater containing heavy metals or oils, wherein the above (1)
The present invention relates to a wastewater treatment method using the silicate compound of

The silicate compound in the present invention is a crystalline compound having an anhydrous composition represented by the general formula xM ₂ O.ySiO ₂ .zM'O. Here, M represents Na and / or K, and M ′ represents Ca and / or Mg. Also,
y / x is 0.5 to 4.0, preferably 0.8 to
2.1, more preferably 1.0 to 1.9. y /
When x is less than 0.5, the water resistance is insufficient, and when it exceeds 4.0, the ion exchange capacity is low and it is not suitable for use as a wastewater treatment agent. z / x is 0 to 1.0, preferably 0.005 to 1.0, and more preferably 0.005.
0.9, particularly preferably 0.01 to 0.6. z /
When x exceeds 1.0, the ion exchange capacity is low and it is not suitable for use as a wastewater treatment agent. x, y, and z are not particularly limited as long as they have the relationship shown in the above y / x and z / x. K / Na is usually 0 to 8.0 from the viewpoint of increasing the cation exchange rate, and preferably 0.01.
Is ~ 8.0. From the viewpoint of increasing the cation exchange capacity, Mg / Ca is usually 0-10, preferably 0.02-
It is 10.

As the silicate compound in the present invention, there are various modes, but preferable examples are as follows. In the above general formula, y / x = 1.9 to 4.0,
_{z / x = 0.005~1.0, M 2} O in the K / Na = 0
8.0, represented by Mg / Ca = 0 in M'O, cation exchange capacity 150mgCaCO ₃ / g or more, and / or oil-absorbing ability is 0.3～3.0Ml / g crystals Silicate compound, in the above general formula, y / x = 0.5 to 1.9,
z / x = 0.005-1.0, K / Na in M ₂ O =
0.01-8.0, Mg / Ca in M'O = 0.02
Cation exchange capacity represented by 10 is 150 mg CaC
O ₃ / g or more, and / or oil absorption capacity is 0.3 to 3.0 ml
/ G crystalline silicate compound

The silicate compound in the present invention may be a hydrate, and the hydration amount in this case is usually 20 mol% or less in terms of the molar amount of H ₂ O.

The silicate compound in the present invention is obtained by synthesis and is composed of three components of M ₂ O, SiO ₂ and M'O as shown in the above general formula. Therefore, in order to produce the silicate compound in the present invention, a substance corresponding to each component is required as a raw material thereof, but a known compound is appropriately used in the present invention without any particular limitation. For example, as the M ₂ O component and M ′ O component, single or complex oxides, hydroxides, salts of the respective relevant elements, and the element-containing minerals are used. Specifically, for example, as the raw material of the M ₂ O component, NaOH, K
OH, Na ₂ CO ₃ , K ₂ CO ₃ , Na ₂ SO ₄ etc.
As the raw material for the M ′ O component, CaCO ₃ , Ca (OH)
₂ , MgCO ₃ , Mg (OH) ₂ , MgO, dolomite and the like. As the SiO ₂ component, silica stone, silica sand, cristobalite stone, kaolin, talc, fused silica, sodium silicate and the like are used.

In the present invention, these raw material components are mixed in a predetermined quantitative ratio so that the desired silicate compound is x, y, z, and usually 300 to 1300 ° C., preferably 5
00-1000 ° C, more preferably 600-900 ° C
Examples of the method include calcination in the range of 1 to crystallize, similarly mixing, and then once melting at 1100 ° C to 1600 ° C to obtain a vitrified product, and then calcining, and further melting and water-vitalizing and calcining. . The heating time is usually 0.1 to 24 hours. Such firing can be usually performed in a heating furnace such as an electric furnace or a gas furnace. Further, after firing, the powder is crushed as necessary to have a predetermined particle size. As the crusher, for example, a ball mill, a roller mill or the like is used. With such a production method, the silicate compound of the present invention having the above-mentioned structural features can be obtained.

The hydrate of the silicate compound according to the present invention can be easily prepared by a known method and is not particularly limited. For example, there may be mentioned a method in which the anhydrous silicate compound obtained as described above is suspended in ion-exchanged water to be hydrated, and dried to be powdered.

The silicate compound in the present invention has an oil absorption capacity of 0.3 to 3.0 ml / g. Oil absorption capacity is 0.3
If it is less than ml / g, the trapping rate of heavy metal ions and surfactants is not sufficient and the performance of wastewater treatment is deteriorated. Also, 3.
When it exceeds 0 ml / g, the specific surface area remarkably increases and the water resistance decreases.

As a method for imparting an oil absorbing ability to the silicate compound in the present invention, the agglomeration of powders described in "Porous Material" (edited by Renichi Kondo, P2, Gihodo, 1973), Examples of the method include foaming, gelation, hydration, and the like, and a method of adding an organic substance such as an acrylic polymer, methyl cellulose, polyvinyl alcohol, etc. disclosed in JP-A-63-270368 and firing.
The present invention is not particularly limited.

The silicate compound or hydrate thereof in the present invention thus obtained has a cation exchange capacity of at least 150 mgCaCO ₃ / g or more, preferably from the viewpoint of efficiently capturing heavy metal ions and surfactants. It has 150 to 600 mg CaCO ₃ / g. In the present invention, the cation exchange capacity refers to the value of cation exchange capacity obtained by the measuring method described below shown in Examples.

In the present invention, water resistance means stability of a silicate compound in water. Therefore, inferior water resistance means that the stability of the silicate compound in water is poor and the Si in water is poor.
This means that the elution amount is increased. On the other hand, “excellent in water resistance” means that the silicate compound has high stability in water and the amount of Si eluted in water is very small. In the silicate compound of the present invention, the amount of Si eluted into water is SiO ₂
It is usually 120 mg / g or less, preferably 90 in terms of conversion.
mg / g or less, more preferably 60 mg / g or less, and most of them are substantially insoluble in water. In the present invention, “substantially insoluble in water” means that the amount of Si eluted when 2 g of a sample is added to 100 g of ion-exchanged water and stirred at 25 ° C. for 30 minutes is usually 100 mg in terms of SiO _2.
Less than / g.

Since the silicate compound in the present invention has the excellent heavy metal ion and surfactant trapping ability, oil trapping ability, oil absorption ability and water resistance as described above, a wastewater treatment agent containing this as an active ingredient is It has excellent wastewater treatment performance. That is, the wastewater treatment agent of the present invention contains the above-mentioned silicate compound as an active ingredient, and the wastewater treatment agent of the present invention is a silicate compound of the above-mentioned silicate compound from the viewpoint of stability in wastewater. In addition, it is composed of various composites of additives such as organic polymers, metal oxides and natural minerals. Here, the compounding amount of the silicate compound in the present invention is usually 20 to 98% by weight, preferably 30 to 90% by weight. If it is less than 20% by weight, the treating ability is low, and if it exceeds 98% by weight, the combined effect is not exhibited.

Further, the wastewater treatment agent of the present invention is used for treating wastewater containing various oil components such as heavy metal ions and surfactants. The wastewater treatment agent of the present invention contains heavy metal types and oil components. Exhibits excellent wastewater treatment effects regardless of type. The amount of the wastewater treatment agent of the present invention used is usually 0.1 to 100 g / liter. Here, the oil component in the present invention is defined as "(24) hexane extract substance" in JIS K102 industrial wastewater test method. Further, the heavy metal ions referred to here include radioactive heavy metal ions.

As a method of treating wastewater containing heavy metals in the present invention, the silicate compound of the present invention may be added to the wastewater alone, or the above-mentioned wastewater treatment agent of the present invention may be added. You may. Similarly, as a method of treating wastewater containing oil, the silicate compound of the present invention may be added to the wastewater alone, or the wastewater treatment agent of the present invention as described above may be added.

[0018]

EXAMPLES The present invention will be described in more detail with reference to Examples, Comparative Examples and Test Examples, but the present invention is not limited to these Examples. The measured values in the examples and comparative examples were measured by the following method.

(1) Cation exchange capacity: 0.1 g of a sample was accurately weighed and added to 100 ml of an aqueous calcium chloride solution (concentration: 500 ppm as CaCO ₃ ),
After stirring at 25 ° C. for 60 minutes, filtration was performed using a membrane filter having a pore size of 0.2 μm (manufactured by Advantech, nitrocellulose), and the amount of Ca contained in 10 ml of the filtrate was measured by EDTA titration. The calcium ion exchange capacity (cation exchange capacity) of the sample was determined from the value. However, in the case of 500 mgCaCO ₃ / g or more,
It is a value measured with the amount of the calcium chloride solution being 200 ml.

(2) Oil absorption capacity 2 g of the powder was stirred and tested in accordance with the pigment test method (oil absorption capacity) of JIS 5101, and calculated by the following formula. Oil absorption capacity (ml / g) = volume of linseed oil dropped (ml)
/ Sample mass (g)

(3) Si elution amount 2 g of the sample was added to 100 g of ion-exchanged water, and the amount was 30 at 2 ° C.
Stir for minutes. After that, centrifugation is performed, and the supernatant is filtered using a membrane filter having a pore size of 0.2 μm. Plasma emission analysis (ICP) of Si concentration in the filtrate
And the elution amount of Si was calculated in terms of SiO ₂ .

Examples 1 to 10 No. 2 sodium silicate (SiO ₂ / Na ₂ O = 2.55, water content 59.9%), sodium hydroxide, potassium hydroxide, anhydrous calcium carbonate and magnesium hydroxide are shown in Table 1. Mixing was performed so as to obtain the composition shown. To this mixture was added polyvinylpyrrolidone 0-2%, and at a temperature of 700 ° C,
After calcination in an air stream and crushing to 60 mesh or less, silicate compound powders 1 to 10 in the present invention were obtained. The oil absorption capacity of these powders is 0.3 to 3.0 ml / g, and the cation exchange capacity is 150 mg CaCO _3.
/ G or more, and had excellent wastewater treatment characteristics. Also, the amount of Si eluted is 120 mg / g or less,
The water resistance was also good.

[0023]

[Table 1]

Comparative Examples 1 to 5 Sodium metasilicate (Na ₂ O.SiO ₂ ) as a special grade reagent
Baking at 00 ° C for 1 hour, purified montmorillonite manufactured by Nippon Talc Co., Ltd., refined hyrosite manufactured by Kyoritsu Ceramic Raw Materials Co., Ltd., refined kaolin manufactured by Kyoritsu Ceramic Raw Material Co., Ltd., Fuji Talc Industrial Co., Ltd. All of the purified talc was crushed to 60 mesh or less and used as comparative powders 1 to 5 (Table 2).

[0025]

[Table 2]

Test Example 1 Model drainage 250 containing 100 ppm of chromium ions
1 g of each of the silicate compounds and the like obtained in Examples 1 to 5 and Comparative Examples 1, 3, and 5 was put into cc, and the mixture was stirred for 30 minutes, and 5
After filtering with a filter paper of No. C, the amount of chromium ions remaining in the filtrate was measured by the atomic absorption method (357.9 nm). The results are shown in Table 3. When the silicate compound of the present invention was used, the residual chromium ion amount was extremely low as compared with the comparative example.

[0027]

[Table 3]

Test Example 2 Model drainage 25 containing 500 ppm of barium ion
1 g of each of the silicate compounds and the like obtained in Examples 6 to 10 and Comparative Examples 2 and 5 was put into 0 cc, and the mixture was stirred for 30 minutes.
After filtering with a filter paper of No. C, the amount of barium ions remaining in the filtrate was measured by the EDTA titration method. The results are shown in Table 4. When the silicate compound of the present invention was used, the residual barium ion amount was extremely low as compared with the comparative example.

[0029]

[Table 4]

Test Example 3 0.5 g of a surfactant (Emulgen PP-230; polyoxyethylene polyoxypropylene; cloudy weather = 24 ° C.)
1 g of each of the silicate compounds obtained in Examples 1, 3 and 5 and Comparative Examples 1 and 3 was put into the model wastewater containing 1 / liter of the mixture, the mixture was stirred for 60 minutes, and filtered through a 5th type C filter paper. Then, this filtrate is subjected to JIS K102 industrial drainage test method (1
Based on 7), COD measurement with potassium permanganate at 100 ° C. was performed to determine the residual concentration of the surfactant. The results are shown in Table 5. When the silicate compound of the present invention is used, the emulgen PP is compared with the comparative example.
The residual concentration of -230 was extremely low.

[0031]

[Table 5]

[0032]

The silicate compound of the present invention has excellent heavy metal ion and surfactant trapping ability, oil trapping ability, oil absorption ability, and water resistance. Therefore, a wastewater treatment agent containing this as an active ingredient is excellent. Has wastewater treatment performance. Therefore, in the treatment of wastewater containing heavy metals or oils (particularly surfactants), by using the silicate compound in the present invention, these can be effectively captured and recovered and removed.

Claims (7)

[Claims] 1. The general formula of the anhydride is xM ₂ O.ySi.
O ₂ · zM ′ O (In the formula, M represents Na and / or K,
M ′ represents Ca and / or Mg, and y / x = 0.5 to
It is 4.0 and z / x = 0-1.0. ), A wastewater treatment agent comprising a crystalline silicate compound having a cation exchange capacity of 150 mgCaCO ₃ / g or more as an active ingredient. 2. The general formula of the anhydride is xM ₂ O.ySi.
O ₂ · zM ′ O (In the formula, M represents Na and / or K,
M ′ represents Ca and / or Mg, and y / x = 0.5 to
It is 4.0 and z / x = 0-1.0. ), A wastewater treatment agent comprising a crystalline silicate compound having an oil absorption capacity of 0.3 to 3.0 ml / g as an active ingredient. 3. The general formula according to claim 1 or 2, wherein the silicate compound is y / x = 1.9 to 4.0, z / x =
0.005~1.0, K / Na = 0~8 in M ₂ O.
The waste water treatment agent according to claim 1 or 2, wherein Mg / Ca in M'O is represented by 0 or 0. 4. The general formula according to claim 1 or 2, wherein the silicate compound is y / x = 0.5 to 1.9, z / x =
0.005~1.0, K / Na = 0.01~ in M ₂ O
The wastewater treatment agent according to claim 1 or 2, which is represented by 8.0 and Mg / Ca in M'O = 0.02 to 10. 5. The amount of Si elution of the silicate compound is 120 m
The wastewater treatment agent according to any one of claims 1 to 4, which is g / g or less. 6. A method for treating wastewater containing heavy metals, which comprises using the silicate compound according to any one of claims 1 to 5. 7. A method for treating wastewater containing oil, which comprises using the silicate compound according to any one of claims 1 to 5.