JP3293705B2 - Water purifier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water purifier for obtaining safe and tasty water, and more particularly to a water purifier capable of removing a compound which impairs safety and taste by limiting an adsorbent.

[0002]

2. Description of the Related Art Activated carbon water purifiers mainly intended to remove residual chlorine contained in tap water have been launched and used several years ago. Bacteria appeared on the activated carbon, which proved undesirable.

[0003] Water purifiers using membrane filtration such as a porous hollow fiber membrane have been put on the market to suppress the outflow of the germs, and this type has recently become the mainstream. Recently, a cassette type water purifier in which an activated carbon storage unit, a separation filtration membrane storage unit, and an ion exchange resin storage unit are further combined has been proposed (Japanese Utility Model Laid-Open No. 3-7989). Although not quantitatively large, water purifiers using reverse osmosis membranes and water purifiers using natural stones, ceramics, etc. as filter media are also on the market.

[0004]

In the above-mentioned water purifiers, those which have not been subjected to membrane filtration, such as porous hollow fiber membranes, are liable to grow germs and flow out to the initial flow of tap water unless used for a long time. There was a problem that would. In order to solve such problems, a water purifier that performs microfiltration using a porous hollow fiber membrane or a flat membrane or a water purifier that has antibacterial properties by, for example, impregnating activated carbon with silver has been developed and put on the market. It has become.

[0005] Activated carbon impregnated with silver is slightly unstable in performance because its antibacterial properties vary depending on the amount of silver eluted and a large amount of silver may not flow out. The method using membrane filtration has sufficient performance to remove various germs and the like if there is no mistake in the method of using and fixing the membrane. If activated carbon is used, it is possible to remove trace amounts of potentially hazardous dissolved organic substances such as trihalomethane and pesticides, depending on the amount and performance of the activated carbon.

However, cations of heavy metals such as lead and anions such as nitrate nitrogen and nitrite nitrogen, which are soluble in piping materials and the like, and which are soluble, are difficult to remove by activated carbon and membrane filtration, and are almost removed. It was not possible at present. In order to remove these ions, a water purifier using a reverse osmosis membrane has been developed.However, it removes all minerals in terms of the taste of drinking water, so the water becomes unpalatable and is called safe and delicious water. In terms of face, there were difficulties.

Therefore, for the purpose of selectively removing the soluble ions and the like as described above, a water purifier has been proposed in which an ion exchange resin is incorporated in a water purification tank in addition to activated carbon and a porous hollow fiber membrane. ing. This water purifier is excellent in removing ionic substances dissolved in raw water. However, even if the ion exchange resin itself is insoluble, impurities and unreacted substances in the production process may remain on the resin surface, and when they elute, they are removed by the microfiltration membrane. It may not be possible to mix in filtered water.

The present invention has been made in view of the above circumstances, and has as its object to provide a water purifier capable of removing not only residual chlorine and various bacteria but also dissolved heavy metal ions in order to obtain safe and delicious water. I do.

[0009]

SUMMARY OF THE INVENTION The gist of the present invention is to provide a septic tank.
Is hydroxyapatite, anion exchange resin, activated carbon
Water purifier characterized by comprising a porous hollow fiber membrane
It is in.

The anion exchange resin is a strong base type anion.
It is preferably an exchange resin. In addition, the anion exchange tree
It is preferable to arrange activated carbon before and after the fat.

According to the present invention, the septic tank is hydroxyapatite ,
Consists of anion exchange resin, activated carbon and porous hollow fiber membrane
Is done.

With hydroxyapatite or activated carbon alone,
When various bacteria are generated, the bacteria may flow out into the initial flow from the water purifier, which is not preferable from the viewpoint of safety. In addition, there is a problem that it is difficult to remove soluble cations of heavy metals such as lead and anions such as nitrate nitrogen and nitrite nitrogen only with activated carbon and hollow fiber membranes.

In the water purifier of the present invention, among hydroxyapatite, anion exchange resin, activated carbon and porous hollow fiber membrane, the porous hollow fiber membrane is desirably present in the last stage of the water purification tank. The hydroxyapatite, anion exchange resin, and activated carbon may be used in any order, or a mixture of three or a mixture of any two may be used.

[0014] Shika乍, the use of anion exchange resins, hypochlorite ions present as residual chlorine is adsorbed, there is a possibility to reduce the exchange capacity of the anion exchange resin, anion
Activated carbon is installed in front of the ion exchange resin,
After the fat, again to adsorb and remove the eluate from the resin
A method of disposing activated carbon is preferred.

As the ion exchange resin used in the present invention, any of a weakly basic ion exchange resin and a strongly basic ion exchange resin can be used as long as they correspond to the substance to be removed.

Elution from a lead pipe used for a water distribution pipe,
For the purpose of removing heavy metals such as lead, which are highly likely to be contained as harmful substances, cation exchange resins, especially water purifiers using strongly acidic cation exchange resins, are used for the following reasons. A cationic cation exchange resin is used.

[0017] Strongly acidic cation exchange resins are generally sold as sodium salts, but are not preferred because sodium exchange is caused by ion exchange, and when used for drinking, problems such as an increase in blood pressure may occur.

Further, if an acid-type strongly acidic cation exchange resin is used to prevent sodium from flowing out, the pH of the effluent becomes 4 or less, which deviates from the tap water quality standard and increases irritation. . Furthermore, it is preferable to use a calcium salt type because eluting ions improve the taste of water and tend to be insufficient in health.

On the other hand, hydroxyapatite is a phosphate of calcium and has an apatite structure. Divalent heavy metals such as lead can be selectively ion-exchanged, at which time calcium ions, which are lattice ions in the crystal, are released as exchange ions. Therefore, ion exchange similar to that of the calcium salt type strongly acidic cation exchange resin is performed.

In the case of hydroxyapatite, it has excellent selectivity for divalent heavy metals, especially lead, and is superior in both exchange efficiency and exchange capacity to commercially available strong acidic cation exchange resins. In addition, hydroxyapatite is also used for anion exchange. However, in the case of nitrate ion or the like, the apatite structure is destroyed by ion exchange. Therefore, when the concentration is high, removal with another removing agent such as an anion exchange resin is preferable.

Further, since the actual concentration of nitrate ions in tap water is not so large as to impair the cation exchange properties of hydroxyapatite, there is no problem in this respect. To solve the problem of elution, hydroxyapatite, as used as a packing material for chromatography, has extremely low solubility in water. There is no problem. Furthermore, it has good adsorption characteristics for organic substances, and can supplement or substitute for the role of activated carbon.

In the case of tap water exceeding the water quality standard, the highest value of all data is 4820 according to the 1990 statistics.
There are only a few of the seven water treatment plants, but may contain nitrate nitrogen and nitrite nitrogen. In addition, in well water, nitrate nitrogen and nitrite nitrogen may be contained in more wells in some cases, and removal of such nitrate nitrogen is also an important issue.

In such a case, it is preferable to use a strongly basic anion exchange resin having a neutral salt decomposing ability.
In general, a strong basic anion exchange resin is commercially available in a chloride form, and if used as it is, nitrate nitrogen and nitrite nitrogen can be removed. In the case of the hydroxide type, the pH of the water flowing out becomes high, which is not preferable.

In the present invention, a porous hollow fiber membrane must be used. Use of a porous flat membrane is not preferable because a sufficient filtration membrane area may not be obtained. The porous hollow fiber membrane of the present invention is not particularly limited as long as minute substances such as various bacteria can be removed, and a porous hollow fiber membrane of a polyolefin type such as polyethylene or polypropylene or a polysulfone type is used. It is preferable that these porous hollow fiber membranes are hydrophilized in order to improve water passage performance.

The activated carbon used in the present invention is not particularly limited as long as it has the ability to reduce residual chlorine and the ability to adsorb harmful substances such as trihalomethane and pesticides. Activated carbon, such as fibrous or molded charcoal, can be used. The raw material is not particularly limited, and natural activated carbon such as coconut shell activated carbon, bone charcoal, and charcoal-based,
Pitch-based, petroleum-coke-based synthetic activated carbon and the like can be used. There is no particular limitation on the activation method, and steam activation,
An activation method such as chemical activation is used.

When used as a water purifier, it is preferable that the bulk water has a large bulk density since the passing speed of the water to be passed through the activated carbon is much higher than that of a normal method of using activated carbon. Preferably, the loss is small. Most of the adsorbed substances have relatively small molecular weights, and in view of cost, granular activated palm carbon activated with steam is currently most preferable.

The activated carbon of the present invention may be one to which a heavy metal such as silver is impregnated for imparting antibacterial properties, but it is not preferable that a large amount of heavy metal is eluted. Those provided with antibacterial properties are relatively preferably used. The hydroxyapatite, activated carbon, anion exchange resin and porous hollow fiber membrane of the present invention may be housed in one container or may be housed in a plurality of containers and combined. Further, a primary filter, ceramics, natural stone, or the like may be used in combination with the above combination.

[0028]

As described above, the present invention provides a hydroxyapat
Site, activated carbon, anion exchange resin, porous hollow fiber membrane
New water purifiers that have been difficult to remove.
Innovative water purification that can remove even dissolved ionic harmful substances
It is a vessel.

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-122493 (JP, A) JP-A-6-114371 (JP, A) JP-A-5-200282 (JP, A) 77881 (JP, U) Japanese Utility Model Hei 5-76593 (JP, U) Japanese Utility Model Utility Model 5-80584 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) C02F 1/28 C02F 1 / 42 C02F 1/44 B01D 35/04

Claims (3)

(57) [Claims] 1. A septic tank comprising hydroxyapatite, an anion
Consisting of an exchange resin, activated carbon and a porous hollow fiber membrane.
And a water purifier characterized by the following. 2. The method according to claim 1, wherein said anion exchange resin is a strongly basic anion.
2. Water purification according to claim 1, wherein the water is an exchange resin.
vessel. 3. An activated carbon before and after the anion exchange resin.
3. Water purification according to claim 2, wherein the water purification is provided.
vessel.