JPH10244253A - Water purifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve sufficiently the removing capability for trihalomethane by active carbon, provide the desorption and regeneration effect by applying hot water and reuse active carbon. SOLUTION: Active carbon 2 in which the pore volume of pares of radius of 10-18Å is 35% or more of the total pore volume filled in a cylindrical case 1, and toxic substances such as trihalomethane and others are adsorbed from raw water. Successively hot water is passed therein to carry out the sufficient desorption and regeneration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water purifier provided with activated carbon, which is used, for example, for purifying domestic tap water and for purifying various types of business water at restaurants and the like.

[0002]

2. Description of the Related Art In recent years, a water purifier has been required to have an ability to remove trihalomethane having carcinogenic properties. But,
There is no activated carbon water purifier that can effectively remove trihalomethane over a long period of time. Conventional water purifiers mainly use any one of granular activated carbon, granular activated carbon, powdered activated carbon, and fibrous activated carbon. Generally, water purifiers using granular activated carbon, granular activated carbon, or powdered activated carbon are said to have poor trihalomethane removal performance from the beginning of use. It is said that the trihalomethane removal ability is completely lost before the trihalomethane is reached, or the trihalomethane concentration increases and the trihalomethane flows out.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a water purifier capable of removing trihalomethane stably and sufficiently over a long period of time.

[Means for Solving the Problems]

[0004] In order to achieve the above object, the water purifier according to the present invention uses activated carbon for purifying raw water of 10 to 18 kg.
Characterized in that activated carbon in which the pore volume of pores having a radius of 35% or more occupies 35% or more of the total pore volume is used.

[0005] The pore size of activated carbon is determined by a water vapor adsorption method. According to the water vapor adsorption method, the pore distribution is not determined for a pore radius of 7 ° or less, but the cumulative pore volume of the entire pores of 7 ° or less is determined. 7 ° or more can be determined as a distribution curve of pore radius and pore volume and a cumulative pore volume curve. According to the present invention, the cumulative pore volume curve
Volume (A) of pores having a pore radius of {-18};
The volume (B) of pores having a pore radius of 00 ° or less is determined, and 100 A / B% is defined as the volume ratio of pores having a pore radius of 10 ° to 18 °. Since pores having a pore radius of 100 ° or more do not affect the ability to adsorb and remove trihalomethane, if there are pores having a pore radius of 100 ° or more, these are ignored in the calculation.

[0006]

The present inventor has studied the ability to adsorb trihalomethane in water on activated carbon. As a result, pores having a pore radius of 18 mm or more have a very low ability to adsorb trihalomethane, and have a fine pore radius of 7 to 10 mm. The pores were found to have very high ability to adsorb trihalomethane. The pore radius is 7-10Å
Pores have the advantage of extremely high adsorption capacity, but when washed with hot water, the desorption amount of trihalomethane is small,
Therefore, there is a drawback that saturation adsorption is reached in a relatively short use period, and the subsequent adsorption capacity is lost.
It has been found that pores having a pore radius of 10 to 18 ° are considered to have a high trihalomethane adsorption ability and a large desorption of trihalomethane when washed with hot water, and exhibit high trihalomethane removal performance when re-watered.

According to the present invention, by using activated carbon in which the pore volume of the pores having a radius of 10 to 18 ° occupies 35% or more of the total volume, trihalomethane is sufficiently adsorbed in the initial stage of water passage. By removing the water, it is possible to obtain purified water having a harmful trihalomethane emission concentration of about 20% or less of the raw water inlet concentration. In addition, when a predetermined amount of water is passed and the emission concentration of trihalomethane increases, by passing hot water of about 65 to 90 ° C. which can be easily obtained even at home,
Most of the trihalomethane adsorbed on the activated carbon is desorbed, the adsorption capacity is restored, and purified water can be stably obtained for a long period of time while keeping the adsorption capacity of the activated carbon high. The higher the hot water temperature, the higher the recovery effect.
When hot water of 100C is obtained, hot water of 100C may be used.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. First Embodiment As shown in FIG. 1, an activated carbon 2 is sealed in a cylindrical case 1 having a raw water inlet 1A at a lower portion and a purified water outlet 1B at an upper portion, and partitions on both end surfaces thereof. The net 9 is applied. In this activated carbon 2, pores having a radius of 10 to 28 ° occupy 35% or more of all the pores. A domestic mixing faucet 4 is connected to a water supply pipe 3 connected to the raw water inlet 1A.
Through the raw water supply pipes 5 and 65 to 90 such as tap water
A hot water (hot water) supply pipe 6 of ° C. is connected.

In the water purifier having the above structure, first, raw water containing trihalomethane, such as tap water, is supplied into the case 1 through the raw water supply pipe 5, the mixing faucet 4, and the water supply pipe 3 to thereby supply the raw water. Raw water passes through the activated carbon 2, the trihalomethane is adsorbed on the activated carbon 2, and purified water having a low trihalomethane concentration is discharged from the outlet 1B. When such purification is performed for an appropriate time, hot water of 65 to 90 ° C. is supplied into the case 1 through the hot water supply pipe 6, the mixing faucet 4, and the water supply pipe 3, and the hot carbon is supplied to the activated carbon. By passing water through the activated carbon 2, the molecular motion of the trihalomethane adsorbed and held on the activated carbon 2 is activated, and most of the trihalomethane is desorbed to recover the adsorption ability of the activated carbon 2.

Next, experimental examples and comparative examples corresponding to the first embodiment will be described. Experimental Example 1 6 g of fibrous activated carbon having a peak at 12 ° and a pore volume having a pore radius of 10 to 18 ° occupying 60% of the total pore volume.
Into a 43 mm diameter cylindrical case to a thickness of 5 cm.
0 ppb trihalomethane (chloroform 25 ppb,
Bromoform 12.5 ppb, dichlorobromomethane 1
2.5 ppb) and 2 L of water containing 2 ppm of free chlorine
(Liter) / min. After passing the water, the initial 200
Up to L, adsorb and remove 80% or more of trihalomethane,
Excellent purified water having a trihalomethane content of 15 ppb or less was obtained. At the time of passing 400 L of water, only 20% of trihalomethane was adsorbed, and trihalomethane was reduced to 40%.
ppb of water was discharged. Next, add 2 L of hot water at 80 ° C.
/ Min. After dewatering for 5 minutes at a flow rate of
The trihalomethane adsorption capacity was restored to 80%. In this state, 75% after passing 30L, 70% after passing 60L,
After passing 100 L of water, it exhibited an adsorption capacity of 65%, and it was recognized that there was a desorption / regeneration effect by hot water. When the same desorption operation was performed again, it showed a trihalomethane adsorption capacity of 77%, which was confirmed to be reproducible. Note that free chlorine was always removed by 90% or more.

Experimental Example 2 Granulated activated carbon having a peak at 10.5 ° and a pore volume having a pore radius of 10 to 18 ° occupying 50% of the total pore volume was 2%.
9 g was packed into a 35 mm diameter cylindrical case to a thickness of 5 cm, and 50 ppb of trihalomethane (chloroform 25 p.
pb, bromoform 12.5 ppb, dichlorobromomethane 12.5 ppb) and water containing 2 ppm of free chlorine at 2 L / min. When 75% of the trihalomethane was initially adsorbed and removed, the trihalomethane became 10 pp.
Excellent purified water of b was obtained. At the time of passing 400 L, only 45% of trihalomethane was adsorbed and removed, and at the time of passing 800 L, only 35% of trihalomethane was adsorbed and removed. Next, 80
° C hot water at 2 L / min. The mixture was desorbed by passing water at a flow rate of 5 minutes for 5 minutes, and the trihalomethane adsorption capacity was restored to 75%. In this state, 70%, 200%
It showed 50% adsorption capacity after passing L water, and it was recognized that there was a desorption / regeneration effect by hot water. When the same desorption operation was performed again, 75% of the trihalomethane was adsorbed and removed. Note that free chlorine was always removed by 90% or more.

Comparative Example 1 6 g of fibrous activated carbon FT-10 manufactured by Kuraray Chemical Co., Ltd.
(Having a peak at 8 ° and a pore volume having a pore radius of 10 to 18 ° occupying 30% of the total pore volume) was packed into a cylindrical case having a diameter of 43 mm to a thickness of 5 cm, and trichloromethane (chloroform of 50 ppb) was added. 25 ppb, bromoform 1
2.5 ppb, dichlorobromomethane 12.5 ppb)
And water containing 2 ppm of free chlorine at 2 L / min. When the water was passed through, the initial 200 L of trihalomethane 80
% Or more, and excellent purified water containing 10 ppb or less of trihalomethane was obtained. However, at the time of passing 400 L of water, only 30% of trihalomethane was adsorbed and removed, and water of 35 ppb of trihalomethane passed.
Next, hot water of 80 ° C. was added at 2 L / min. When desorbed by passing water at a flow rate of 5 minutes for 5 minutes, the trihalomethane adsorption capacity was restored to 80%.
After passing 0 L and 60 L of water, it showed only 30% adsorption capacity. That is, the regeneration effect by the hot water was small.

Comparative Example 2 29 g of a granular activated carbon GW32 / 60 manufactured by Kuraray Chemical Co., Ltd., which is used in a normal activated carbon water heater (having a peak at 10 ° and having a pore volume of 10 to 18 ° with a pore radius of 10 to 18 °). Water containing 5 ppm of trihalomethane (25 ppb of chloroform, 12.5 ppb of bromoform, 12.5 ppb of dichlorobromomethane) and 2 ppm of free chlorine At 2 L / min. As a result, 80% of the trihalomethane was initially adsorbed and removed, and excellent purified water with a trihalomethane concentration of 10 ppb was obtained. But,
At the time of passing 400 L of water, only 50% of the trihalomethane was adsorbed and removed, and at the time of passing of 800 L of water, only 30% of the trihalomethane was adsorbed and removed. Next, hot water of 80 ° C. was added at 2 L / min. When the water was passed for 5 minutes at a flow rate of 5 hours to desorb the water, the trihalomethane adsorption capacity was restored to 60%. In this state, the water returned to the adsorption capacity of 30% after passing 100 L of water, and the desorption / regeneration effect by hot water was reduced. There were few.

Second Embodiment FIG. 2 shows a second embodiment in which fibrous activated carbon and granular activated carbon are combined.
An example will be described. In the figure, the purified water outlet 1B is
Is enclosed in a cylindrical case 1 having pores having a radius of 10 to 18 ° and occupying 35% or more of the total pore volume. And a granular activated carbon 8 is filled in another cylindrical case 7 fitted and connected to the lower end opening of the cylindrical case 1. A partition net 9 is provided on the upper surface of the granular activated carbon 8.
A raw water supply pipe 5 such as tap water is supplied to a water supply pipe 3 connected to the raw water inlet 7A through a household mixing faucet 4.
And a hot water (hot water) supply pipe 6 of 65 to 90 ° C.

In the water purifier having the above configuration, first, raw water containing trihalomethane and free chlorine, such as tap water, is supplied into the case 7 through the raw water supply pipe 5, the mixing faucet 4, and the water supply pipe 3. As a result, the raw water passes through the granular activated carbon 8 in the former stage, and most of substances that have a bad influence on the human body such as malodorous substances, organic substances, free chlorine and the like, and a part of trihalomethane is adsorbed and removed. Subsequently, the raw water passes through the fibrous activated carbon 2 at the subsequent stage, the remaining trihalomethane is adsorbed by the fibrous activated carbon 2, and purified water having a low trihalomethane concentration is discharged from the outlet 1B.

As described above, since a part of the trihalomethane is removed by the granular activated carbon 8, the burden on the fibrous activated carbon 2 is reduced, and the carbon is hardly saturated. On the other hand, the granular activated carbon 8 is inherently less saturated than the fibrous activated carbon 2. Therefore, the ability to adsorb and remove free chlorine and trihalomethane is maintained high even by passing a large amount of raw water. as a result,
It is possible to reduce the frequency of the regeneration operation using hot water.

Next, an experimental example and a comparative example corresponding to the second embodiment will be described. EXPERIMENTAL EXAMPLE 3 16 g of the granular activated carbon used in Experimental Example 2 was packed to a thickness of 2.5 cm in front of a cylindrical case having a diameter of 43 mm, and 3 g of the same fibrous activated carbon used in Experimental Example 1 was filled in the cylindrical shape. Packed in the latter part of the case, 50 ppb of trihalomethane (chloroform 25 ppb, bromoform 12.5 ppb,
Dichlorobromomethane (12.5 ppb) and water containing 2 ppm of free chlorine at 2 L / min. As a result, 100% of both free chlorine and trihalomethane were adsorbed and removed in the initial stage, and excellent purified water was obtained. In addition, even when 400 L of water was passed, 0.1 ppm of free chlorine and 15 ppb of trihalomethane also showed excellent purification performance. That is, even if a large amount of raw water is passed, the decrease in the adsorption removal ability is small. The desorption / regeneration effects on the fibrous activated carbon and the granular activated carbon are shown in Experimental Examples 1 and 2 corresponding to the first embodiment described above.
The same results as in Example 2 were observed.

As a known technique, Japanese Patent Application Laid-Open No. 60-64 is disclosed.
No. 686 describes a technique for treating water treated with the granular activated carbon at the preceding stage with fibrous activated carbon at the subsequent stage. In this case, however, it is necessary to make the SV (space velocity) very slow, 5 to 50 L / h. there were. In the case of the present invention, SV is set to 500 to 2000 by appropriately setting the pore size of activated carbon.
It is possible to keep the ability to adsorb and remove free chlorine and trihalomethane at a very high level. The SV of Experimental Example 3 is 1650.

The activated carbon in the present invention includes:
It may be fibrous or granular.
In the case of fibrous activated carbon, it is relatively easy to control the pore size distribution, and it is easy to produce activated carbon in which the pore volume having a pore radius of 10 to 18 ° accounts for 50% or more of the total pore volume.
In the case of granular activated carbon, it is difficult to make activated carbon having a sharp pore size distribution, but by controlling production conditions,
It is possible to produce those having an 18 ° pore diameter of 35 to 60%.

[0020]

As described above, according to the water purifier of the present invention, activated carbon in which the pore volume of pores having a radius of 10 to 18 ° occupies 35% or more of the total pore volume is used. In the initial stage of water passage, trihalomethane can be sufficiently adsorbed and removed to obtain excellent purified water having an emission concentration of harmful trihalomethane equal to or lower than the emission allowable standard, and can be easily obtained at home and the like. By passing hot water of about 90 ° C. or less, most of the trihalomethane adsorbed on the activated carbon is desorbed, its adsorption ability is restored, and the activated carbon can be reused. Therefore,
The high ability to remove trihalomethane can be exerted for a long period of time without the need for uneconomical and troublesome replacement of activated carbon. Note that the present invention can be similarly applied to a hollow fiber type water purifier in which a hollow fiber membrane is provided after activated carbon.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a water purifier according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing a water purifier according to a second embodiment of the present invention.

[Explanation of symbols]

1 ... case, 2 ... fibrous activated carbon, 5 ... raw water supply pipe, 6 ...
Hot water supply pipe.

Claims (1)

[Claims] 1. A water purifier provided with activated carbon for purifying raw water, wherein the activated carbon has a pore volume of pores having a radius of 10 to 18 ° occupying 35% or more of the total pore volume. And water purifier.