JPH07171385A - Mold-odor removing material - Google Patents

Abstract

PURPOSE:To obtain a mold-odor removing material which is effective to remove musty substances in drinking water, especially 2-MIB, by using fibrous active carbon having a specific surface area and pore distribution as the mold-odor removing material. CONSTITUTION:Fibrous active carbon is used which is characterized by: specific surface area of 1500m<2>/g or more; cumulative pore volume of pores with radii 10-20Angstrom measured by a water-vapor adsorption method of 0.2cc/g or more; the cumulative pore volume of pores with radii 10-20Angstrom measured by the water-vapor adsorption method occupying 50% or more of the cumulative pore volume of pores with radii 100Angstrom or less. The mold-odor removing material by the use of the fibrous active carbon is effective to remove mold odor in drinking water, particularly city water; besides, it effectively removes other odor substances.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold odor removing material composed of fibrous activated carbon having a specific pore structure. More particularly, it relates to a mold odor removing material suitable for removing the mold odor of drinking water, particularly tap water.

[0002]

2. Description of the Related Art In recent years, there has been a growing interest in drinking water, especially tap water quality, and along with this, there have been many complaints about tap water quality, most of which are related to odor which greatly affects the taste of water. It is said that the number of people suffering from offensive odors reaches 22 million in Japan. Examples of odors in drinking water such as tap water include chlorine odor, mold odor, and rust odor such as iron rust. Among them, mold odor is 2-methylisoborneol (2- (2-methylisoborneol) generated from algae such as holmium and oscilatoria. MIB) is said to be the main cause.

With increasing interest in the water quality of drinking water, water purifiers filled with various forms of activated carbon, such as granular, powdery and fibrous forms, have come into widespread use, and patent applications relating to activated carbon for water purification have been filed. Many have been issued. However, conventional activated carbon for water purification has been developed for the purpose of removing chlorine and trihalomethane which is said to have carcinogenicity, and research and development have progressed with regard to removal of mold odor, which is a major cause of complaints. The current situation is not. The reason is 2-MIB contained in tap water.
Is very low concentration of several tens of ppt (parts per trillion), it is difficult to be adsorbed by activated carbon because of being disturbed by other organic compounds.
It can be mentioned that the IB analysis is not easily performed and takes time.

[0004]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a material effective for removing odorous substances contained in drinking water, particularly harmful substances such as 2-MIB which is said to be the cause of musty odor. That is.

[0005]

Means for Solving the Problems As a result of repeated studies by the present inventors in order to achieve the above object, when fibrous activated carbon having a specific specific surface area and pore distribution is used, an odorous substance in drinking water, In particular, it is possible to effectively remove 2-MIB, which causes mold odor, and does not contain 2-MIB.
The present invention has been completed by finding that drinking water having no offensive odor such as musty odor can be obtained.

That is, according to the present invention, (a) the specific surface area is 1
500 m ² / g or more, (b) the cumulative pore volume occupied by pores having a pore radius of 10Å to 20Å measured by the water vapor adsorption method is 0.2 cc / g or more, and (c) the water vapor adsorption method. A musty odor characterized by comprising fibrous activated carbon in which the cumulative pore volume occupied by pores having a measured pore radius of 10Å to 20Å is 50% or more of the cumulative pore volume occupied by pores having a pore radius of 100Å or less. It is a removal material.

Here, the "specific surface area" (hereinafter referred to as "SA") (m of the fibrous activated carbon used in the mold odor removing material of the present invention) (m
² / g) means a value determined by the BET method using a nitrogen gas adsorption isotherm at the liquid nitrogen temperature. Further, the "cumulative pore volume occupied by pores having a pore radius of 10Å to 20Å measured by a water vapor adsorption method" (hereinafter referred to as "V _10-20 ") of the fibrous activated carbon
(cc / g) and the “cumulative pore volume occupied by pores having a pore radius of 100 Å or less” (hereinafter referred to as “V ₁₀₀ ”) (cc / g) measured by the same method are pores prepared by the following method. It is defined based on the distribution curve.

[Method of creating pore distribution curve] Since the equilibrium water vapor pressure of a sulfuric acid aqueous solution having a constant concentration has a constant value, there is a uniform relationship between the sulfuric acid concentration of the sulfuric acid aqueous solution and the equilibrium water vapor pressure. Fibrous activated carbon was placed in the vapor phase part of the adsorption chamber in which a sulfuric acid aqueous solution having a predetermined concentration was present, and contacted with water vapor under the conditions of 1 atm (absolute pressure) and 30 ° C. The saturated adsorption amount (weight) of water was measured.
On the other hand, the pores of the fibrous activated carbon used for the adsorption of water in the measurement test of the saturated adsorption amount are 1 atm (absolute pressure) peculiar to the sulfuric acid concentration of the adopted sulfuric acid aqueous solution, and the equilibrium water vapor pressure at 30 ° C. Kelv expressed by the following formula 1 from the value (P)
It has a pore radius equal to or smaller than the pore radius (r) obtained based on the formula of in. That is, the cumulative pore volume of pores having a pore radius or less, which is obtained based on the Kelvin equation, is the volume of water at 30 ° C. corresponding to the saturated adsorption amount in the measurement test. Similarly, using the same kind of fibrous activated carbon, 13 kinds of sulfuric acid aqueous solutions having different sulfuric acid concentrations (that is, having a specific gravity of 1.05 to 1.30 at intervals of 0.025 11 Seed sulfuric acid aqueous solution, sulfuric acid aqueous solution having a specific gravity of 1.35, and sulfuric acid aqueous solution having a specific gravity of 1.40), a saturated adsorption amount measurement test was performed, and in each measurement test, The cumulative pore volume was determined. The pore distribution curve of the fibrous activated carbon can be obtained by plotting the cumulative pore volume against the pore radius based on the data of the cumulative pore volume thus obtained.

[0009]

## EQU1 ## Kelvin's formula : r =-[2Vm γ cos θ] / [RT ln (P / P ₀ )] In the formula, r: Pore radius (cm) Vm: Molecular volume of water (cm ³ / mol) = 18.079
(30 ° C.) γ: Surface tension (dyn / cm) = 71.15 (30 ° C.) θ: Using contact angle (°) = 55 ° between capillary wall and water R: Gas constant (erg / deg · mol) ) = 8.314
3 × 10 ⁷ T: Absolute temperature (K) = 303.15 P: Saturated vapor pressure (mmHg) of water in pores P ₀ : 1 atm (absolute pressure) of water, saturated vapor pressure at 30 ° C.
(mmHg) = 31.824

From the above pore distribution curve, the pore radius corresponding to the requirement (b) in the present invention is 10Å to 20.
The cumulative pore volume (V _10-20 ) occupied by the pores of Å is determined, and from the values of the V _10-20 and V ₁₀₀ , V _{10 to 20} relative to V ₁₀₀ which is the requirement (c) in the present invention is calculated. Ratio (%)
_{Is calculated} from the formula: (V _10-20 / V ₁₀₀ ) × 100.

The fibrous activated carbon used in the mold odor removing material of the present invention has the three requirements (a) to (c) described above, that is, SA of 1500 m ² / g or more and V _10-20 of 0.
2 cc / g or more, and (V _10-20 / V ₁₀₀ ) × 10
It is necessary to have all the characteristics of three requirements that 0 is 50% or more. By having these three requirements, it is the first cause of odorous substances contained in drinking water, especially tap water, especially musty odor.
It is possible to efficiently remove MIB, and (a) ~
Odorous substances, especially 2-M, if any of the requirements of (c) are lacking
IB cannot be removed efficiently. Among the fibrous activated carbons having the above-mentioned requirements (a) to (c), SA is 2000 m ² / g or more and V _10-20 is 0.
4 cc / g or more and (V _10-20 / V ₁₀₀ ) × 10
A fibrous activated carbon having 0 of 75% or more is preferable because it has a great effect of removing mold odor.

The fibrous activated carbon used in the mold odor removing material of the present invention preferably has an average fiber diameter of 5 to 30 μ, and particularly preferably 5 to 20 μ. If the average fiber diameter of the fibrous activated carbon is less than 5μ, the water resistance becomes large when it is filled in a water purifier and the like, and it becomes difficult to remove the musty odor efficiently, while the average fiber diameter is 30
When it exceeds μ, the fiber itself becomes brittle, and when filling the water purifier,
Alternatively, it is not preferable because it is crushed during the production of a molded body for filling a water purifier from the fibrous activated carbon and a large amount of fine powder is generated, which causes troubles. Moreover, the length of the fibrous activated carbon is not particularly limited, and may be a short fibrous shape or a long fibrous shape.

The fibrous activated carbon used in the mold odor removing material of the present invention may be any fibrous activated carbon which satisfies all of the above three requirements (a) to (c). Raw materials used to produce activated carbon, production conditions (eg, infusibilizing conditions, carbonizing conditions, activation conditions, etc.),
The manufacturing device and the like are not particularly limited. As an example of a preferable manufacturing method, a raw material fiber such as a phenolic resin fiber is prepared by about 60
Whether to treat with steam and / or carbon dioxide gas in a nitrogen stream by selecting conditions under which a fibrous activated carbon having the above three requirements (a) to (c) can be obtained at a high temperature of 0 to 1400 ° C. Alternatively, a method of activation treatment with combustion gas can be used.

The fibrous activated carbon used in the mold odor removing material of the present invention can be filled in a water purifier in a fibrous form such as a felt form, a cut fiber form, a filament form or a tow form, or a sheet form or a cylindrical form. It can be shaped into various shapes such as a cylindrical shape, a prismatic shape, and a plate shape, and can be filled in the water purifier.
Further, when shaping into such various shapes in order to facilitate filling, a binder made of a polymer compound may be used, and therefore the mold odor removing material made of fibrous activated carbon in the present invention is used. The fibrous activated carbon itself that satisfies the above requirements (a) to (c), and those obtained by shaping the activated carbon without or using a binder are included.

In terms of facilitating the filling of the water purifier and filling the predetermined amount of the fibrous activated carbon into the water purifier, the fibrous activated carbon is preset in advance according to the internal shape and size of the water purifier. It is convenient to shape the shape.
In shaping, any method such as a method of directly pressing and shaping with a binder and a method of joining fibers by a binder and shaping can be adopted as long as the ability to remove musty odor is not lost.

When the binder is used for shaping, various binders such as a fibrous or powdery thermoplastic polymer and a solution or dispersion of a polymer compound can be used.
Among them, it is preferable to use a binder or a microfibrillated fiber made of a fibrous thermoplastic resin in that the pores on the surface of the fibrous activated carbon are less likely to be blocked, and particularly a sheath component having a low melting point and a higher melting point than that. It is preferable to use a binder composed of a core-sheath type composite fiber composed of a core component. The amount of the binder used is not particularly limited, but is usually about 5 to 40% by weight based on the weight of the fibrous activated carbon.
It is better to use the degree.

The present invention will be specifically described below with reference to examples and the like, but the present invention is not limited thereto. In the following examples, SA, V _10-20 , V ₁₀₀ and (V _10-20 / V ₁₀₀ ) × 1
00 was measured by the method described above.

Example 1 (1) Phenolic resin fiber (long fiber having an average fiber diameter of 14 μ) (manufactured by Nippon Kynol Co., Ltd .; Kynol KT2)
400) was introduced into a vertical slit furnace and L of 1030 ° C.
PG combustion gas (H ₂ O / CO ₂ / CO / H ₂ obtained by burning a mixed gas with a volume ratio of propane / air of about 1/20)
/ C ₃ H ₈ / N ₂ mixed gas) is supplied to the inside of the furnace and activated under the condition of a residence time of 14 minutes in the furnace to obtain an average fiber diameter of 1
0μ, SA = 2380 m ² / g, V _10-20 = 0.81c
c / g, V ₁₀₀ = 0.93 cc / g, (V _10-20 /
V ₁₀₀ ) × 100 = 87% of fibrous activated carbon was obtained. This fibrous activated carbon was cut into a length of 5 mm, and 60 g thereof was filled in a cylindrical container for water purification having an inner diameter of 8 cm and a length of 8 cm.

(2) Total organic carbon (TOC) concentration of 2.5
Sodium hypochlorite was added to ppm river water to bring the free chlorine concentration to 2 ppm, to which was added chloroform 25 ppb and bromodichloromethane 10 pp as trihalomethanes.
b, dibromochloromethane were added at a concentration of 10 ppb and bromoform at a concentration of 5 ppb, respectively, and 2-MIB was further added at a concentration of 100 ppt (parts per trillion) to prepare a test raw water.

(3) The raw water prepared in (2) above is passed through the cylindrical container filled with the fibrous activated carbon obtained in (1) above at a rate of 4 liters / minute (sv600 hr ⁻¹ ). Treated and treated effluent from the container is Tek
After concentrating using LSC2000 (Purge and Trap Concentration Introducing System) from Mar Inc., 2-MIB in the outflow water is analyzed every two hours by GC-MS (gas mass), and the limit of 2-MIB concentration that can be sensed by humans When the total amount of water passed until the concentration of 10 ppt, which is said to be above, was examined, it was 179,040 liters as shown in Table 1 below.

Example 2 (1) of Example 1 except that the residence time in the furnace during the production of fibrous activated carbon was 10 minutes.
The same treatment as above is performed to obtain an average fiber diameter of 10 μm and SA = 20.
20 m ² / g, V _10-20 = 0.54 cc / g, V ₁₀₀ =
0.67 cc / g, (V _10-20 / V ₁₀₀ ) × 100 = 81
% Fibrous activated carbon was obtained. This fibrous activated carbon was cut into a length of 5 mm, and 60 g of the fibrous activated carbon was filled into a cylindrical container for water purification having an inner diameter of 8 cm and a length of 8 cm, which was used in Example 1
When the same water flow test as in (3) above was performed, the total water flow amount until the 2-MIB concentration in the outflow water exceeded 10 ppt was 111,600 liters as shown in Table 1 below.

Example 3 The fibrous activated carbon obtained in the same manner as in (1) of Example 1 was cut into a length of 5 mm, and 100 parts by weight of the activated fibrous carbon was used as a binder for polyester fiber (single fiber). 20 parts by weight of fiber denier = 1 denier, length 5 mm) was added, and papermaking was carried out by a tappy paper machine to obtain a sheet having a basis weight of 150 g / m ² . The obtained sheet was pressed under the conditions of 130 ° C. and 8 kg / cm ² for 3 minutes, placed between hot plates with controlled gaps, and pressed at 260 ° C. for 2 minutes to obtain a density of 0.15 g / cc. A molded sheet was produced. This sheet was cut into a disk shape having a diameter of about 8 cm, and filled in a cylindrical container of the same type as that of Example 1 so that the filling amount was about 60 g. A water permeation test similar to (3) of Example 1 was conducted using this,
The total water flow amount until the 2-MIB concentration in the outflow water exceeded 10 ppt was 124,800 liters as shown in Table 1 below.

Comparative Example 1 The temperature of the LPG combustion gas was set to 9
The same treatment as in (1) of Example 1 was performed except that the temperature was set to 80 ° C. and the residence time in the furnace was set to 9 minutes to obtain an average fiber diameter of 10 μ,
SA = 1290 m ² / g, V _10-20 = 0.05 cc /
g, V ₁₀₀ = 0.05 cc / g, (V _10-20 / V ₁₀₀ ) ×
Fibrous activated carbon of 100 = 13% was obtained. This fibrous activated carbon was cut into a length of 5 mm, and 60 g thereof was filled in a cylindrical container of the same type as in (2) of Example 1. When the same water flow test as in (3) of Example 1 was conducted using this, the total water flow amount until the 2-MIB concentration in the outflow water exceeded 10 ppt was 12,72 as shown in Table 1 below.
It was 0 liter.

Comparative Examples 2 to 4 SA shown in Table 1 below.
Value, V _10-20 value, V ₁₀₀ value and (V _10-20 / V ₁₀₀ ) × 1
Commercially available phenolic resin fibrous activated carbon having a value of 00 (Comparative Example 2), coal pitch fibrous activated carbon (Comparative Example 3) and phenolic resin fibrous activated carbon (Comparative Example 4)
60 g of each of the above was charged into a cylindrical container of the same type as in (2) of Example 1, and a water permeation test similar to that of (3) of Example 1 was carried out using this, and 2 The total water flow rate until the MIB concentration exceeds 10 ppt is shown in Table 1 below.

Comparative Example 5 The same commercially available fibrous activated carbon used in Comparative Example 3 was cut into a length of about 5 mm,
In the same manner as in Example 3, using a binder to press to produce a molded sheet having a density of 0.15 g / cc,
This was cut into a disk shape with a diameter of about 8 cm, and filled in a cylindrical container of the same type as (2) of Example 1 so that the filling amount was about 60 g. When the same water flow test as in 3) was conducted, the total water flow rate until the 2-MIB concentration in the outflow water exceeded 10 ppt is shown in Table 1 below.
It was 8,880 liters as shown in.

[0026]

[Table 1] SA V _10-20 V ₁₀₀ (V _10-20 / V ₁₀₀ ) 2-MIB exceeds 10ppt (m ² / g) (cc / g) (cc / g) × 100 (%) (Liter) Example 1 2380 0.81 0.93 87 179040 Example 2 2020 0.54 0.67 81 111600 Comparative Example 1 1290 0.05 0.38 13 12720 Comparative Example 2 1620 0.15 0.45 33 30480 Comparative Example 3 1340 0.02 0.30 7 1440 Comparative Example 4 1980 0.30 0.65 46 64800 Example 3 − − − − 124800 (shaped object) Comparative Example 5 − − − − 8880 (shaped object)

From the results of Table 1 above, it is _confirmed that all of SA, V _10-20 and (V _10-20 / V ₁₀₀ ) × 100 satisfy the above requirements (a) to (c) in the present invention. The shaped body of Example 3 made from the fibrous activated carbons of Examples 1 and 2 and the fibrous activated carbon of Example 1 has extremely high ability to remove 2-MIB, which is the causative agent of mold odor, and is filled with fibrous activated carbon. The concentration of 2-MIB in the effluent water from the container was able to treat an extremely large amount of water until the human perceptible limit of 10 ppt was exceeded (the total amount of water passed was extremely high), and it was It can be seen that the MIB can be effectively removed.

On the other hand, SA, V _10-20 and (V
_When the fibrous activated carbons of Comparative Example 1, Comparative Example 3 and Comparative Example 5 in which all of _{10 −20} / V ₁₀₀ ) × 100 do not satisfy the above requirements (a) to (c) in the present invention are used,
The fibrous form of Comparative Example 2 in which the total amount of water flow until the concentration of 2-MIB in the effluent exceeds 10 ppt is extremely small, about 1/10 or less of that in Examples, and which satisfies only the requirement (a). When activated carbon is used, the total amount of water flowing until the concentration of 2-MIB in the effluent exceeds 10 ppt is about one-third or less than that of the example, and further satisfies the requirements (a) and (b). When the fibrous activated carbon of Comparative Example 4 which does not satisfy the requirement (c) is used, 2-MI of the outflow water is used.
The total amount of water to be passed until the concentration of B exceeds 10 ppt is about half or less than that of the examples, and any comparative example is significantly inferior in the removal ability of 2-MIB as compared with Examples 1 to 3. You can see that

[0029]

INDUSTRIAL APPLICABILITY SA, V _10-20 and (V _10-20 /
When the mold odor remover of the present invention comprising fibrous activated carbon in which all of V ₁₀₀ ) × 100 meet the above requirements (a), (b) and (c) in the present invention, drinking water is used. In particular, it can effectively remove the musty odor which is a big problem in tap water. for that reason,
The mold odor removing material of the present invention can be effectively used for water purifiers used in various places such as homes, factories, stores, and companies, and can maintain good water quality of drinking water for a long period of time. The mold odor removing material used in the present invention is not only effective in removing mold odor due to its excellent adsorption performance, but also odorous substances other than mold odor contained in drinking water, chlorine, trihalomethane, etc. Of course, harmful substances can also be effectively removed.

Claims (1)

[Claims] 1. A specific surface area of 1500 m ² / g or more, and a pore radius of 10Å measured by a water vapor adsorption method.
The cumulative pore volume occupied by ~ 20Å pores is 0.2cc / g
And (c) the cumulative pore volume of pores having a pore radius of 10Å to 20Å measured by the water vapor adsorption method is 50% or more of the cumulative pore volume of pores having a pore radius of 100Å or less. A mold odor removing material characterized by comprising fibrous activated carbon.