JPS61242687A - Purified water generator - Google Patents

Abstract

PURPOSE:To remove surely bacteria, endotoxin, various ions, etc., in untreated water for a long period by arranging a filter module, an activated carbon adsorption device, an ion-exchange resin adsorption device and a filter module. CONSTITUTION:(a) A filter module 2 consisting of a polyolefin porous hollow yarn membrane having 1-10kg/cm<2> bubble point, (b) an activated carbon adsorption device 3 and an ion-exchange resin adsorption device 4 and (c) a filter module 5 consisting of a polyolefin porous hollow yarn membrane having 1.5-10kg/cm<2> bubble point are successively arranged in the water flowing direction. The water permeability of the polyolefin porous hollow yarn membranes (a) and (c) is regulated to >=3l/m<2>.min.kg/cm<2>. Bacteria, endotoxin, various ions, etc., in untreated water can be surely removed with such a purified water generator of simple structure capable of being conveniently used and pollution by bacteria can be prevented for a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to an apparatus for producing endotoxin-free sterile purified water.

[Conventional technology]

Endotoxin-free sterile purified water production equipment is widely used in the pharmaceutical industry, various life science related industries, laboratories, testing rooms, artificial dialysis water, hospital water production, etc. Osmosis membrane equipment, ultrafiltration membrane equipment, etc. are used.Vaporization requires a large amount of energy, and endotoxins cannot be removed sufficiently unless distillation is repeated multiple times.Reverse osmosis membrane Although this method is effective in removing endotoxins, calcium, iron, aluminum, etc., it is not sufficient to remove free chlorine and chloramines, and activated carbon must be used in combination to remove these.However, activated carbon does not kill bacteria. The growth promotes bacterial growth on the reverse osmosis membrane, which tends to leak into the treated water, leading to the production of endotoxins.Moreover, reverse osmosis membranes require high-pressure pumps, making the equipment expensive. Ultrafiltration membranes have a slightly simpler device than reverse osmosis membranes, but they require ion exchange resin in addition to activated carbon for deionization, and bacteria can grow in the activated carbon and ion exchange resin. It becomes a problem.

In addition to the above-mentioned devices, water purification devices using activated carbon and water softeners are often used in the production of water for artificial dialysis.

However, in this case, although activated carbon absorbers are effective in removing chlorine, bacteria tend to grow on the activated carbon, so the water treated by such devices may contain more bacteria and bacterial-derived endotoxins than the raw water. In some cases, the endotoxin concentration can reach several tens of times that of the raw water. JP-A-55-132603 proposes a method in which raw water is filtered through a hollow fiber membrane such as PVA and then treated with a cation exchange resin and an anion exchange resin, but this method does not use activated carbon. Even if it is possible to prevent the proliferation of bacteria caused by chlorine ions, the removal of chlorine ions will be insufficient. Furthermore, endotoxin removal is also insufficient. Also, JP-A-56-44
No. 005 proposes a method in which raw water is filtered with a hollow fiber membrane such as PV'A, treated with a cation exchange resin, and further treated with activated carbon. However, this method cannot sufficiently remove endotoxin,
Furthermore, even if the infiltration of bacteria from the raw water side can be suppressed by a hollow fiber membrane, it is not possible to completely prevent the infiltration of bacteria into the activated carbon when the operation is stopped because there is no second filtration membrane on the downstream side. This is difficult, and once even a small amount of bacteria has infiltrated, its proliferation is unavoidable. Therefore, there is a high risk that the endotoxin concentration will rise.

[Problem that the invention seeks to solve]

This invention can reliably and virtually completely remove bacteria, endotoxins, various ions, etc. from raw water, prevent contamination by bacteria for a long period of time, and has a simple structure and is easy to use. The purpose is to provide a simple purified ice manufacturing device.

[Means for solving problems]

The above objects of this invention are (a) 1 kg/c
A filtration module consisting of a polyolefin porous hollow fiber membrane with a bubble point of ta~10 kg/cl, (b) an activated carbon adsorber and an ion exchange resin adsorber, and (C) a bubble point of 1.5 kg/ct~10 kg/cm2. A purified water production device comprising permodji beans made of polyolefin porous hollow fiber membranes having bubble points in this order with respect to the water flow direction; and (a) 1 kg/
7 filtration modules consisting of a polyolefin porous hollow fiber membrane with a bubble point of cm2 to 1゜kg/cJ, (b) an activated carbon adsorber and an ion exchange resin adsorber,
and (c) 1.5 kg/crA ~10 kg
It has a filtration module made of a polyolefin porous hollow fiber membrane having a bubble point of /c- in this order with respect to the flow direction of water, and further has a container for an ion exchange resin regeneration solution, and a container for the ion exchange resin This is achieved by a purified water production apparatus in which an adsorber and an activated carbon adsorber are connected so that the regeneration liquid can be circulated.

The polyolefin porous hollow fiber membrane used in the above device preferably has a water permeability of 3 R7g -min -kg/cm2 or more.

[For production]

As described above, the purified ice manufacturing apparatus of the present invention has a structure in which an activated carbon adsorber and an ion exchange resin adsorber are provided between two sets of filtration modules. Since a polyolefin porous hollow fiber membrane is used as the filter medium in the first filtration module, bacteria are completely removed in the first filtration module, and most of the endotoxins are also removed. Next, anions such as chlorine ions and various cations are substantially completely adsorbed and removed by an activated carbon adsorption device and an ion exchange resin device.Finally, the remaining endoxins are substantially completely removed by a second filtration module. will be removed.

In this device, bacteria from the raw water is completely removed by the first filtration module, and backflow of bacteria is completely prevented by the second /p filtration module, so activated carbon and ion exchange resin are removed once. Sterilization prevents bacterial growth on activated carbon for a long period of time.

[Embodiment]

FIG. 1 schematically shows the basic configuration of the present invention. 1 is raw water to be supplied, which includes any raw water such as tap water and ground water. Further, 1' indicates purified water (product). 2
is the first filtration module, and 5 is the second filtration module. 3 is an activated carbon adsorption device, and 4 is an ion exchange resin adsorption device.

The activated carbon adsorber and ion exchange resin adsorber can be arranged in any order, and the order shown in FIG. 1 is only one example.

In the filtering module shown by No. 2, a polyolefin hollow fiber membrane having a bubble point of 1.0 kg/cJ to 10 kg/cJ is used. Polyethylene, polypropylene, etc. are used as the material for this hollow fiber membrane, and polyethylene is most preferred. Although the method for manufacturing this hollow fiber membrane is not particularly limited, it can be manufactured, for example, as follows, and one in which microfibrils are stacked in a rectangular shape to form micropores is particularly preferred. That is,
By appropriately controlling each process condition in the main process of cold-stretching highly oriented crystalline undrawn hollow fibers obtained by melt-spinning a polyolefin polymer using a special nozzle for manufacturing hollow fibers, and then heating-stretching them. Manufactured.

Such polyolefin porous hollow fibers have a special microstructure as shown in FIG. That is, FIG. 6 is a schematic diagram of one plane of a stacked structure of strip-shaped micropores, 21 is a microfibril, 22 is a nodule where the ends of a large number of microfibrils 21 arranged almost in parallel are connected, and 23 is a The slit-like micropores 23 are formed of microfibrils and nodules and have a laminated structure with each nodule interposed therebetween. Furthermore, the laminated structure of micropores means that the fibers are laminated in the length direction of the fibers in one plane through the nodules, and at the same time, the planes with such a structure are stacked in the direction of the thickness of the wall membrane of the hollow fibers. .

The inner diameter of the hollow fiber is generally preferably about 200 μm to 500 μm, and the membrane thickness is preferably about 10 μm to 100 μm.

The bubble point of the hollow fiber membrane used in filtration module 2 (first filtration module) is 1.0 kg/ctA
~10 kg/-. Bubble points are 1 and 0
If it is lower than kg/ca, bacteria may permeate depending on the conditions and the endotoxin removal ability of the device will decrease, which is not preferable. Also, bubble point is 1
If it is higher than 0 kg/cm2, the amount of water permeation decreases and the water treatment capacity of the device decreases, which is not preferable.

The above-mentioned bubble point is measured as follows using a measuring device schematically shown in FIG. In the figure, reference numeral 18 denotes a hollow fiber module, in which 48 hollow fibers are bundled into a loop shape, and the ends are bonded with epoxy resin to form an opening. The length of the module is approximately IQ cm. Module J and 18 are placed in ethanol 19, first, cock 15 is closed, cock 16 is opened and vacuum is drawn through 17, and the inside of the hollow fiber pores is sufficiently wetted with ethanol. Next, close Kotsuk 16,
Open cock 15 and pressurize with nitrogen gas from ]4 to 0.
Boost the pressure in steps of 1 kg/c++I. The holding time for each pressure is 10 seconds. The pressure is increased while observing the bubble generation situation, and the pressure at which bubbles are generated from the entire hollow fiber is defined as the bubble point.

The hollow fiber membrane used in filter module 2 is 3 e /
Ruco having water permeability of rd-min -kg/cA or more is preferable, and 10 R/r+(・min -kg
It is particularly preferable to have a water permeability of /cm2. If the water permeability is too low, the water treatment capacity of the device will decrease and an excessive filtration area will be used to treat a given amount of water, which is undesirable.

Of this invention? The p-permomodule is produced using a hollow fiber membrane as described above according to a conventional method. The filtration method may be either an internal pressure method or an external pressure method, but the external pressure method is generally preferred. Also, it is possible to use a cross-flow one-way system, but is it usually the whole amount? The p-pass method is sufficient.

Depending on the quality of the raw water, a pre-filter (not shown) may be provided in front of the filtration module 2 in FIG. The prefilter may be selected depending on the quality of the water, but a prefilter using polyolefin microfibers is particularly problematic in terms of endotoxin removal.

The supply pressure of raw water is usually tap water pressure, but if necessary, it can be pressurized using a pump.

In FIG. 1, 3 is an activated carbon adsorption device, and 4 is an ion exchange resin adsorption device. In this invention, the order of these activated carbon adsorbers and ion exchange resin adsorbers is not particularly limited; contrary to the order shown in FIG. 1, the ion exchange resin adsorbers are placed in front, and then the activated carbon adsorbers You can also put

The activated carbon adsorber 3 preferably has a disinfectant supply port 6 in two parts and a discharge port 6' in the lower part. As the activated carbon, any activated carbon commonly used in water treatment, such as crushed coconut charcoal, can be used. In the apparatus of the present invention, bacteria do not grow in the activated carbon adsorber, but activated carbon added with a silver compound can also be used for safety. In this case, it is preferable to arrange an ion exchange resin adsorption device after the activated carbon adsorption device so that the ion exchange resin adsorbs and removes trace amounts of silver ions eluted from the activated carbon adsorption device.

The ion exchange resin in the ion exchange resin adsorber 4 is as follows:
Especially when the purpose is to produce purified water from which ions have been removed,
It is preferred to use both a cation exchange resin and an anion exchange resin, which can be used in a mixed bed system or packed in separate columns. In this case, the ion exchange resin adsorption device of the present invention will be comprised of a plurality of columns. Also, the removal of anions is relatively unimportant in the production of water for dialysis, and in this case only cation exchange resins (water softeners) can be used. The ion exchange resin adsorber 4 has a supply port 6 and a discharge port 6' for supplying an ion exchange resin regenerating solution or a disinfectant solution.

5 in Fig. 1 is the second filtration module, and this module has a bubble point L of 1.5 kg/c♂~10 kg.
/cn! It is composed of a polyolefin hollow fiber membrane with This hollow fiber membrane has the structure described above for the hollow fiber membrane of the first filtration module 2. The upper limit of the bubble point of the hollow fiber membrane of filtration module 5 is 10 kg/cJ when used in the same way as the hollow fiber membrane of filtration module 2.
The lower limit is 1.5 kg/c-. If the bubble point is lower than 1.5 kg/c+J, it is difficult to completely remove endotoxin, and the hollow fiber membrane of the filtration module 5, which forms the final part of the device of the present invention, needs to completely remove endotoxin. Therefore, it is necessary to have a pubble point of 1.5 kg/, 1. The water permeability of the hollow fiber membrane of the filtration module 5 is
For the same reason as mentioned above regarding the hollow fibers of the filtration module 2, 317 m"-min-kg/c+I1 or more is preferable, and 10 ft/m"-min-kg/
Particularly preferred is cl.

FIG. 2 shows a second embodiment of the device of the invention.

In this figure, numbers 1.1', 2.3. and 5 have the same meaning as in FIG. In FIG. 2, column 4',
and 7 constitute the ion exchange resin adsorption device of the present invention, and 4
' is filled with a cation exchange resin, and 7 is filled with an anion exchange resin. 8 is a container for an aqueous hydrochloric acid solution for regenerating the cation exchange resin, and this container 8, the cation exchange column 4', and the activated carbon adsorption device 3 are connected in circulation through a pipe 11 so that the aqueous hydrochloric acid solution for regeneration can be circulated. ing. When an aqueous hydrochloric acid solution is passed through the column 4' in order to regenerate the cation exchange resin, the aqueous hydrochloric acid solution is simultaneously passed through the activated carbon adsorber 3, and at this time the activated carbon is disinfected. The apparatus further has a tank 9 of an aqueous sodium hydroxide solution for regenerating the anion exchange resin in the column 7, and this tank 9 is connected to the column 7 by a pipe 11 so that the regeneration liquid can be circulated through the column 7. ing.

FIG. 3 shows a third embodiment of the device of the invention.

In this figure, numbers 1.1', 2, 3, 4. and 5 have the same meanings as in FIG. 1, and 12 is a tank for a sodium chloride aqueous solution for regenerating the resin in the ion exchange resin absorber (water softener) 4 filled with the ion exchange resin. be. This tank 12 is connected to the ion exchange resin adsorber 4 so that the regeneration liquid is circulated through the activated carbon adsorber 3, and these adsorbers 3 and 4 are connected by a vibrator 13. has been done. The regenerating liquid can also be circulated in the opposite direction to that described in -J-. In either case, by heating the regenerating liquid to 65° C. or higher and using it, the activated carbon adsorber 3 can be disinfected at the same time as the regeneration point of the ion exchange b1 fat in step 4.

Next, the apparatus of the present invention will be further explained with reference to examples.

U-For example, in the apparatus shown in FIG. P hypermodule 2 is made of a laminated structure of slit-like micropores produced by cold stretching and hot stretching of undrawn crystalline polyethylene yarn.Bubble point I□ 3.9 k+r/cnt
, water permeability 11 j! 7m2・min-kg/cn+
A module made of porous polyethylene hollow fibers having an inner diameter of 270 m and a membrane thickness of 55 m+ was used. membrane 1
The filtration area was 0.2n+2. The filtration module 5 has the same structure as the old one, and has bubble points l-4 and 8.
kg/cJ.

Water permeability 6.77! /m2-m1n-kz/c inner diameter 27
A module made of porous polyethylene hollow fibers having a membrane thickness of 0 μm and a membrane thickness of 55 μm was used. Filtration area is 0.2m
500 g of coconut shell activated carbon was used as the activated carbon in the activated carbon adsorber 3. Amberlite MB2 type 1a was used as the ion exchange resin in the ion exchange resin adsorber 4. Thoroughly disinfected with ethanol. Endotoxin activity 2
．． The water was introduced from 1 at a rate of 8 ng/mβ (determined by Seikagaku Kogyo (determined by barrel pyrodic)), and purified water was taken out from 1'.

The relationship between the cumulative amount of filtrated water and the endotoxin concentration in purified water is shown in Figure 5C.

Comparative Example 1 The filtration module 2 in FIG.
The same water flow experiment as in Example 1 was carried out using the same apparatus as in Example 1 except that it was placed after the .

The results are shown in FIG. 5B.

Comparative Example 2 The same water flow experiment as in Example 1 was conducted using the same apparatus as in Example 1 except that the activated carbon adsorber in FIG. 1 was removed. The results are shown in FIG. 5A.

Example 2 The apparatus shown in FIG. 2 was used. filtration modules 2 and 5,
In addition, the activated carbon 3 was the same as in Example 1.

In this device, the ion exchange resin adsorber consists of a column 4' packed with a cation exchange resin and a column 7 packed with an anion exchange resin, using Amberlite IR-120B at 0.51 as the cation exchange resin. , and Amberlite TRA400 as an anion exchange resin.
β was used. From 1 to 1, city tap water was passed through at a rate of 1,201 per day. 1/11 cation exchange resin per week
By regenerating with 50 g of hydrochloric acid and further circulating this regenerating liquid to the activated carbon adsorber 4, the activated carbon was disinfected at the same time as the resin was regenerated. When the number of bacteria and mold in the activated carbon was measured one month later, no bacteria or mold were observed.

A water flow experiment similar to that of Example 2 above was conducted. However, the resin regenerating liquid (hydrochloric acid aqueous solution) was not passed through the activated carbon adsorber 3. One month later, a small amount of bacteria, thought to be contaminated from the environment, was found in the activated carbon.

The device shown in Figure 3 was used. ” overmodules 2 and 5,
In addition, the activated carbon was the same as in Example 1.

There are 17 ion exchange resin adsorbers (water softeners) in 4! Amberlite 1R120B was filled. 80 per week
Sodium chloride aqueous solution (regenerated solution) heated to ℃ (resin 1
The ion exchange resin was regenerated by passing 300 g of sodium chloride per water softener 4 through the water softener 4, and at the same time, the activated carbon was disinfected by passing the regenerated liquid through the activated carbon adsorber 3. After one month, no bacteria were detected in the activated carbon.

Comparative Example 4 An experiment similar to Example 3 was conducted. However, a sodium chloride aqueous solution at room temperature was used as the regenerating liquid. One month later, a small amount of bacteria was found in the activated carbon.

〔Effect of the invention〕

The device of the invention has a very simple structure and is simple to use. Since the apparatus of the present invention includes two sets of filtration modules made of polyolefin porous hollow fiber membranes and an activated carbon adsorption device, it is possible to substantially completely remove bacteria, other microorganisms, endotoxins, and the like. The apparatus of the present invention also includes an ion exchange resin adsorber, so that, depending on the choice of ion exchange resin, cations, anions, or both can be substantially completely removed.

Furthermore, in the apparatus of the present invention, since the activated carbon adsorber and the ion exchange resin adsorber are arranged between the two sets of filtration modules, the bacteria contained in the raw water are
filtration module, and bacterial backflow is removed by the second filtration module.
filtration module. Therefore, once the activated carbon adsorber and ion exchange resin adsorber are sterilized,
These sterile conditions are maintained for a long period of time, and bacterial growth on the activated carbon is prevented for a long period of time.

Therefore, highly purified water can be continuously produced for a long period of time. This is clearly shown by the graph in FIG.

Furthermore, in the second and third aspects of the apparatus of the present invention, when the ion exchange resin is regenerated, the activated carbon is also disinfected at the same time, so highly purified water can be produced continuously for an extremely long period of time. be able to.

[Brief explanation of drawings]

FIG. 1 shows a basic aspect of the device of the invention; FIGS. 2 and 3 show other aspects of the device of the invention; FIG. 4 shows a bubble point measuring device; FIG. 5 6 is a graph showing the long-term durability of the device of the invention in terms of endotoxin activity; and FIG. 6 shows a preferred structure of the polyolefin porous hollow fiber membrane used in the device of the invention. In the figure, ■ indicates raw water, 1' indicates filtered water, and 2 indicates the first
of? , a filtration module, 3 is an activated carbon adsorber, 4 is an ion exchange resin adsorber, and 5 is a second filtration module. In Fig. 2, 4' is a cation exchange resin column, and 7 is an anion exchange resin column. When multiple types of ion exchange resins are used separately, these columns can be used to adsorb the ion exchange resin of the present invention. The vessel is constructed. 8,9. and 12 are tanks for ion exchange resin regenerating liquid, respectively. Fig. 1 Fig. 2 (argument) Cumulative filtration water volume (m3) Fig. 5

Claims (1)

[Claims] 1. (a) A filtration module consisting of a polyolefin porous hollow fiber membrane having a bubble point of 1 kg/cm^2 to 10 kg/cm^2, (b) an activated carbon adsorber and an ion exchange resin adsorption container, and (c) 1.5kg/cm^2
A purified water production apparatus having filtration modules made of polyolefin porous hollow fiber membranes having a bubble point of ~10 kg/cm^2 in this order in the water flow direction. 2. The polyolefin porous hollow fiber membrane (a) and (
The device according to claim 1, wherein c) has a water permeability of 3 l/m^2·min·kg/cm^2 or more. 3. (a) A filtration module consisting of a polyolefin porous hollow fiber membrane having a bubble point of 1 kg/cm^2 to 10 kg/cm^2, (b) an activated carbon adsorber and an ion exchange resin adsorber, and (c) 1.5kg/cm^2
It has a filtration module made of a polyolefin porous hollow fiber membrane having a bubble point of ~10 kg/cm^2 in this order with respect to the water flow direction, and further has a container for an ion exchange resin regenerated liquid, and this container and the above-mentioned A purified water production apparatus in which an ion exchange resin adsorber and an activated carbon adsorber are connected so that the regeneration liquid can be circulated. 4. The polyolefin porous hollow fiber membrane (a) and (
The device according to claim 3, wherein c) has a water permeability of 3 l/m^2·min·kg/cm^2 or more.