JPS6053680B2 - Clean water law - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water purification method, and in particular to a water purification method for removing manganese, or iron and manganese that have an adverse effect on products, piping, equipment, etc. in drinking water or various industrial water. be.

If manganese or iron is present in so-called drinking water or industrial water, even if each of them is in trace amounts,
This causes problems such as coloration, contamination, deterioration of taste, and scale formation.

Therefore, these are each 0.
It is specified as 3 pμm or less, and limits are also set for other industrial waters. The dissolved state of these components in water is that both manganese and iron often exist in the form of bicarbonate and primary sulfate, and the amount varies depending on the region,
Although it varies depending on the water quality, manganese content is often 1 to 3 ppm, and iron content is often 2 to 10 ppm.

Various methods have been used to remove these components, among which the following methods are typical.

First, regarding oxidation methods, air oxidation, chlorine oxidation, hydrogen peroxide, or potassium permanganate oxidation are common methods.In air oxidation, iron may precipitate as ferric hydroxide, but manganese Oxidation will not proceed unless the pH is raised to 10 or higher.

Other strong oxidizing agents such as chlorine and potassium permanganate can also oxidize manganese, but in this case too, the pH has to be increased and, above all, the cost is high. On the other hand, contact filtration methods include a catalytic filtration method that uses an oxidation catalyst as a filter material, and a manganese zeolite method that has oxidizing power and a catalytic effect.

The former is a coating formed of manganese sand or soft manganese ore with sand as the base material, and although it does not have ion exchange ability, it changes into a manganese dioxide-containing salt when used in combination with an oxidizing agent.

The latter is made by attaching a higher order oxide of manganese to a filter material that has a certain degree of ion exchange ability, such as green sand or synthetic zeolite, and can be fixed as manganese dioxide by its oxidizing power.

Both of these contact filtration methods can effectively remove manganese; It is known that there are difficulties in the operation of depositing cancerous oxide, the regeneration frequency, and the regeneration cost, and furthermore, it is known that the oxidation rate becomes extremely slow when silica components or organic substances are present.

In addition to the above methods, there is also a microbial oxidation method! It is.

This uses the biochemical oxidation effect of iron bacteria to oxidize manganese to manganous(II) hydroxide.
It accumulates on the surface or inside of bacterial cells. Although this method is effective depending on how it is applied, it can be said to be uncommon in terms of handling. In short, in these conventional techniques, although iron removal is relatively simple, a method for effectively treating manganese with simple operations has not yet been found. The purpose of the present invention is to eliminate the various defects in the above-mentioned prior art, and in response to the request for removal, effectively fix manganese or iron and manganese by adding chloride and electrolyzing, and then, The purpose of this invention is to provide a water purification method in which products can be separated and removed using a sand filtration tank or the like.

The water purification method according to the present invention oxidizes and removes manganese, or iron and manganese in the water by adding chloride to water and electrolyzing the water.
An embodiment of the water purification method according to the present invention will be described below with reference to the drawings, together with a water purification device used for carrying out the method.

First, things related to manganese removal will be explained.

In Fig. 1A, at the opening, 1 is an electrolytic cell part, 2 is a sand filter tank part, 3 is a sodium chloride injection system part into which sodium chloride water is to be injected, 4 is a DC power supply, 5 is an air blowing system section, 6 is treated raw water, 7 is an anode, 8 is a cathode, 10 is an air bubble, 11 is an exhaust pipe, 12
is a bypass circuit, 13 is a blow pipe, and 14 is treated water.

That is, the above-mentioned apparatus has a system capable of continuous processing, and is mainly composed of an electrolytic cell section 1 and a sand filtration tank section 2, and a sodium chloride injection system section 3 as ancillary equipment. , a DC power source 4 and an air blowing system section 5.

Then, the treated raw water 6 enters the electrolytic cell section 1 with sodium chloride water injected from the sodium chloride injection system section 3 on the way. Further, the electrolytic cell of the electrolytic cell section 1 has an anode 7
A concentric circular electrode is formed by the inner cylinder of the cathode 8 and the outer cylinder of the cathode 8,
The cathode 8 is arranged in an outer cylinder so that the liquid comes out uniformly on the outer periphery.
As shown in the opening of the figure, it is shaped like a grid.

With the above configuration, sodium chloride is added to the treated raw water 6 from the sodium chloride injection system section 3 and injected into the electrolytic cell section 1, and while bubbling with air etc. from the air blowing system section 5, both the electrodes 7, 8 This method performs direct current electrolysis.

Due to the electrolysis of sodium chloride in the electrolytic cell section 1, manganese ions in the treated raw water 6 are oxidized by the chlorine and sodium hypochlorite, and are made insoluble by oxidation at the anode 7. This precipitates a product mainly consisting of manganese dioxide.

The hydrogen gas generated at the same time as the above electrolysis is made up of fine air bubbles 1 that are press-injected from the lower part of the electrolytic cell section 1 from the air blowing system section 5.
0 also makes it possible to maintain the generated amount within a safe range.

At the same time, the air bubbles 10 within the electrolytic cell of this electrolytic cell section 1, in addition to serving as the diluting medium, also serve to clean each electrode surface, suppress concentration polarization, and remove residual chlorine. It's useful. Thus, the air containing the diluted hydrogen gas mentioned above is radiated outdoors through the exhaust pipe 11 provided at the upper part of the electrolytic cell section 1. The manganese product fixed in the electrolytic cell of the electrolytic cell section 1 described above is separated in the sand filter section 2 installed in a cylindrical shape outside the tank. In addition, when the function of the filtration tank in the sand filtration tank section 2 deteriorates, the treated raw water 6 is sent through the bypass circuit 12 to backwash the sediment and discharge it from the blow pipe 13. The filter tank can be regenerated. In this way, treated water 14 is generated from this sand filter tank section 2 and sent out.

What has been described above, in short, is to add sodium chloride to the manganese ions dissolved in the treated raw water and perform DC electrolysis, and through this electrolysis, chlorine and sodium hypochlorite are removed. The manganese is generated and oxidized, and electrolytic oxidation is performed at the anode.

On the other hand, the above-mentioned air bubbling is intended for stirring, is a so-called secondary method, and is not absolutely necessary. Further, other possible methods can be arbitrarily adopted as the stirring means including the stirring medium. As mentioned above, when using the air method, it is effective in removing deposits on both electrodes, suppressing the reduction of concentration polarization, and diluting chlorine and hydrogen gas generated during electrolysis. The manganese thus fixed is removed in a separator such as a filtration tank to produce clean treated water, which can then be supplied. In addition, regarding the water purification apparatus for purification treatment, the one used for the water purification method according to the above embodiment is particularly designed so that the electrolytic cell in the electrolytic cell part is made into a double cylindrical shape, and a sand filtration tank part is provided on the outer periphery of the electrolytic cell. This configuration allows for a large processing area and allows the overall configuration to be made into a compact integrated device, which means that it can be adapted for home use. .

Sand is used as the filtration medium, but there is no reason to limit it to sand, and it does not preclude the use of other filtration media; however, when sand is used, it can be made at a lower cost. It has a special effect.

Regarding the electrodes used for electrolysis, it is desirable to use a platinum-plated plate, ferrite plate, etc., which will not be affected by chlorine gas, for the anode, and a lead or zinc plate, etc., which has a large hydrogen overvoltage, for the cathode. .

Regarding the configuration of the water purification device used in the above-mentioned Water Purification Act, the parts shown at A and B in Fig. 2 are different from those in Fig. 1, and the parts with the same symbols as in Fig. 1 are as follows: Equivalent parts are shown, and 9 is an electrode plate. That is, it is similar to the one shown in FIG. 1 in that it has a system that allows continuous processing, but the arrangement of the electrode plates including both electrodes is different. In other words, the anode 7 is placed at the bottom, and the cathode 8 is placed at the top, and a large number of electrode plates 9 are placed between them to form a bipolar structure, making the whole structure integrated and increasing the electrode area. It was designed to force the
It is subjected to the same processing method as in FIG. Experimental results to prove the functions of the water purification method and the device described above are shown in FIGS. 3 and 4.

That is, FIG. 3 shows the electrolytic treatment characteristics of water containing manganese.

The sample water was a solution in which 0.1y of sodium sulfate was added to 100mL of manganese sulfate solution to improve conductivity.

The electrolytic cell in the electrolytic cell section has a ferrite plate as an anode and a zinc plate as a cathode, which are arranged facing each other at regular intervals.
) The electrolytic conditions were kept constant at a DC current of 0.15 A, and sampling was performed during the current application time, and after filtering with 5 A filter paper, the liquid was measured using an atomic absorption spectrometer. As a result, the manganese concentration decreases with electrolysis, but does not remain constant at around 1 ppm. On the other hand, the pH of the liquid shows a tendency to decrease. Therefore, it is considered that manganese is removed by redissolving the fixed manganese due to a decrease in pH.

Further, FIG. 4 shows the electrolytic treatment characteristics when sodium chloride was added and air was blown.

The electrolytic cell and electrodes used were the same as those for the experimental results shown in Figure 3, and the electrolytic conditions were 100 ml of sample water and 0.0 mL of saline.
At the same time as adding 3y and electrolyzing the air at 0.5f/Mi
It was sent in by n. The results showed that manganese rapidly decreased with electrolysis, and it took 2.5 minutes to reduce manganese to 0.3 ppm.

The amount of current flowing at this time is 15 coulombs, which is 150 coulombs/l when converted into the amount of current flowing per capacity. on the other hand,
The concentration of remaining chlorine increases with electrolysis, but
It can be reduced to 0.2-0.5 ppm by air blowing. The fact that manganese products can be sufficiently removed by performing sand filtration for separation in these cases of manganese fixation can be supported by the fact that the manganese products can be separated using 5A filter paper.

In summary, in the above embodiments, manganese ions dissolved in water are electrolytically oxidized by additives such as sodium chloride, and in other words, by air blowing. This is a water purification method that effectively removes water by combining a so-called sand filter, and its effects can be summarized as follows.

1 Manganese is effective by electrolytic sodium hypochlorite. It is possible to process down to low concentrations.

2 The produced manganese oxides can be easily separated using a cylindrical sand filter.

3. Hydrogen gas generated during electrolysis can be diluted by air bubbles blown into the electrolytic cell and dissipated within a safe range! Ru.

4 Coloring components or odors caused by iron ions or organic substances coexisting in water can be decomposed by electrolytic chlorine, which also has a sterilizing effect.

Regarding the above water purification method and each water purification device, ≦ indicates an example in which it is applied to remove manganese, and it goes without saying that these can be used to remove manganese and iron. be. Next, embodiments related to the removal of manganese and iron will be described with reference to FIGS. 5 to 7.

In FIG. 5, 1A is an electrolytic cell part, 2A is a sand filter tank part, 3A is a sodium chloride injection system part, 4A is a DC power supply, 5A is an air blowing system part, 6A is a treated raw water, 7A
is the anode, 8A is the cathode, 9A is the pump, 10
A is an air bubble, 11A is an exhaust pipe, 12A is a bypass circuit, 13A is a blow pipe, and 14A is treated water. That is, the water purification device having the above configuration used for implementing the water purification method according to this embodiment has a system capable of continuous treatment, and mainly includes an electrolytic cell section 1A that is separated from each other and communicated with each other. It consists of a sand filtration tank section 2A, and its incidental equipment includes a sodium chloride injection system section 3A, a DC power supply 4A, and an air blowing system section 5A.

Then, the treated raw water 6A is pumped by a pump 9A,
Sodium chloride water is injected from the sodium chloride injection system section 3A midway through the piping and enters the bottom of the electrolytic cell section 1A.

Further, the electrolytic cell of the electrolytic cell section 1A is formed in a cylindrical shape, and has an anode 7A, which can have a large electrode area, formed in the outer casing, and a cathode 8A formed in the inner cylindrical portion.

Furthermore, the sand filtration tank section 2A is separate from the electrolytic cell section 1A, and is positioned, for example, in a lower stage thereof, and is connected to the electrolytic cell section 1A through a continuous pipe to form a communication structure.

With the above configuration, sodium chloride is added to the treated raw water 6A from the sodium chloride injection system section 3A and fed into the electrolytic cell section 1A, and DC electrolysis is performed by both electrodes 7A and 8A.

By electrolyzing this sodium chloride in the electrolytic cell in the electrolytic cell section 1A, the chlorine and sodium hypochlorite
Manganese and iron ions in the treated raw water 6A are oxidized, and oxides mainly composed of insoluble manganese dioxide and iron hydroxide are precipitated by anodic oxidation.

Hydrogen gas generated at the same time as electrolysis is injected as fine air bubbles 10A from the lower part of the electrolytic cell section 1A through the air blowing system section 5A so as to be kept safe in relation to the amount generated.

The air bubbles 10A in the electrolytic cell section 1A are useful for cleaning the electrode surface, promoting air oxidation of iron, and removing residual chlorine. , to be dissipated outdoors through the exhaust pipe 11A.

Note that the press-fitting of the air bubbles 10A is secondary, as in the case of each of the previous embodiments.

Iron fixed in the electrolytic cell of the above-mentioned electrolytic cell section 1A,
Water containing manganese products overflows from the top and
It is guided to the next sand filter tank section 2A.

Here, since the above-mentioned product is in the form of particles, it can be easily separated by passing it through the sand filter tank section 2A.

In addition, when the performance of the sand filtration tank section 2A (7) filtration tank deteriorates, the treated raw water 6A is sent from the lower part of the tank through the bypass circuit 12A to remove sediment, and then released from the blow pipe 13A. It is something to do.

The water thus treated is supplied as treated water 14A.

What has been described above, in short, is to perform DC electrolytic treatment by adding, for example, about 300 ppm of chlorides such as sodium chloride to the manganese and iron ions contained in the raw water to be treated, and during the electrolysis. , Chlorine gas is generated by the discharge of chlorine ions and absorbed into the liquid, becoming sodium hypochlorite. Through oxidation by this and electrolytic oxidation at the anode, iron is converted to ferric hydroxide. , manganese becomes oxides such as MnO2 and MnO(0H), and these products can be removed with a backwashable separator such as a filtration membrane or sand filtration to supply clean water. This is what I did.

In addition, hydrogen gas generated during electrolysis is explosive, so to prevent this, air bubbles are introduced into the electrolytic cell to oxidize the air, and hydrogen gas is oxidized to the air, for example. It was designed to be diluted to less than % and released.

Note that it is also desirable that the electrodes used for electrolysis be made of the same materials as those described in the previous embodiment.

Regarding the water purification method and the functions of the equipment described above,
Experimental results demonstrating this are shown in FIGS. 6 and 7.

That is, FIG. 6 shows the electrolytic treatment characteristics of water containing iron and manganese.

The sample water is 100% tap water containing manganese sulfate and ferrous sulfate.
This is a solution in which 0.03y of sodium chloride was added to mt.

The electrolytic cell in the electrolytic cell section has a ferrite plate as an anode and a zinc plate as a cathode facing each other. Furthermore, air was fed into the lower part of the electrolytic cell from a diffuser pipe (portion indicated by a dotted line at the lower part of each electrolytic cell) at a rate of 1'/min. The electrolysis conditions were kept constant at 0.1 A of direct current, and sampling was performed during the electrolysis time, and the liquid filtered through 5A filter paper was measured using an atomic absorption spectrometer.

As a result, iron decreased immediately with electrolysis, and manganese decreased to 0.3 ppm in 3 minutes. The amount of energization at this time was 18 coulombs, and when converted into the amount of energization per capacity, it was 180 coulombs/l. on the other hand,
The remaining available chlorine tends to increase with electrolysis, and although 2 to 3 ppm remained in the sample after 5 minutes, it can be further reduced by adjusting the amount of air. Next, FIG. 7 shows the experimental results when the iron and manganese fixative solution after the electrolytic treatment shown in FIG. 6 was passed through a sand filter tank. The liquid used in the test was manganese 4
This is a liquid containing fixed 6 ppm of iron. and,
The filter tank has sand with an average size of 30 mesh and a diameter of 50 TIUn.
The cylinder is filled to a height of 1507 m. It also shows the amount of permeation and the iron and manganese concentrations when the fixing solution is subjected to gravity sedimentation filtration from above into the filtration tank.

According to the figure, the amount of permeation shows a tendency to decrease with time, but it takes about 5 hours for the amount to decrease by 30%.

On the other hand, the iron and manganese concentrations in the permeated water show that iron is slightly higher than manganese, and that the concentrations increase after 4 hours.

This is due to the difference between iron being a colloid of water and ferric oxide, while manganese is an oxide particle, and the fact that deposits are gradually washed away. be. In any case, it has been confirmed that products of glue, iron, and manganese can be removed by passing through a sand filter tank, and it has also been confirmed that adhesion and sediment can be removed by backwashing. It is something that

In summary, the above embodiments use additives such as sodium chloride and, in short, air blowing to separate manganese and iron ions dissolved in water through electrolytic oxidation. This water purification method uses a vessel to purify water, and its effects can be summarized as follows.

1. Iron and manganese can be effectively treated to low concentrations by electrolytic hypochlorous acid sorter and anodic oxidation.

2 The generated oxides are in the form of particles and can be easily separated using a sand filter tank that can be backwashed.

3. Coloring components and odors caused by organic substances contained in water can be decomposed and sterilized with electrolytic chlorine.

4. Hydrogen gas generated during electrolysis can be diluted by air bubbles blown into the electrolytic cell and dissipated within a safe range.

Taking all the points mentioned above into consideration, the water purification method of the present invention eliminates various deficiencies in the conventional technology and easily removes manganese or manganese and iron in drinking water or industrial water by a simple method. that can be removed and have significant sanitary and industrial effects;
It can be said to be an outstanding invention.

[Brief explanation of the drawing]

Fig. 1A shows a schematic open front view and plan view of a water purification device used for carrying out the water purification method according to an embodiment of the present invention, and Fig. 2A shows a different configuration from the water purification device described above. 3 and 4 are diagrams showing electrolytic treatment characteristics of water containing manganese, and FIG. FIG. 6 is a schematic open front view of a water purification device;
FIG. 7 is a diagram of its filtration characteristics. 1, 1A... Electrolytic tank section, 2, 2A...
Sand filter tank section, 3,3A...Sodium chloride injection system section, 4,4A...DC power supply, 5,5A...
...Air blowing system section, 6,6A...Treatment raw water, 7,7A...Anode, 8,8A...Cathode,
9...Pole plate, 9A...Pump, 10,1
0A...Air bubble, 11,11A...Exhaust pipe, 1
2,12A...Bypass circuit, 13,13A・
...Blow pipe, 14, 14A... Treated water.

Claims (1)

[Claims] 1. A water purification method characterized by adding chloride to water and electrolyzing it to oxidize and remove manganese, or iron and manganese in the water. 2. The water purification method according to claim 1, in which electrolysis is performed while stirring simultaneously with the addition of chloride. 3. The water purification method according to claim 1 or 2, which involves introducing air bubbles to dilute hydrogen gas and chlorine gas generated during electrolysis and also exhausting the gas. 4. A water purification method according to any one of claims 1 to 3, which provides clean water by filtering oxidation products and removing solid content.