JPS6320196B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a filter medium for water purification that removes manganese, iron, and coloring from lake water, river water, etc.

In recent years, lake water, rivers, etc. have become significantly polluted, and the amount of raw water that is not suitable for drinking water has been increasing.As a result, treatment equipment has become more complex and treatment costs have also increased considerably.

Conventionally, commonly used methods for removing coloring caused by manganese, iron, and humic substances in raw water include oxidation using ozone or oxidizing agents, adsorption using activated carbon, contact filtration using manganese-impregnated zeolite, and using flocculants. There is a coagulation-sedimentation method or a treatment method that combines these methods.

Oxidation methods that use oxidizing agents such as ozone or potassium permanganate are expensive, and treatment methods that use ozone in particular require equipment to prevent air pollution. Furthermore, in the adsorption method using activated carbon, there is almost no adsorption ability for manganese and iron, and the ability to remove coloring is also low.

On the other hand, in the contact filtration method, manganese zeolite with manganese dioxide attached to the surface is mainly used. This is produced by mixing zeolite with a liquid containing divalent manganese ions and then adding an oxidizing agent such as potassium permanganate to impregnate manganese dioxide on the surface of the zeolite. However, this method requires a considerable amount of expensive chemicals such as potassium permanganate, resulting in high processing costs, and if the raw water contains a large amount of manganese, a good removal effect cannot be expected. Furthermore, since the surface is coated with manganese dioxide, there is a large loss and deterioration due to shedding or leakage of manganese dioxide.

It has been generally accepted that manganese dioxide itself is effective in removing manganese, iron, and coloring from water, but in order to obtain an appropriate particle size for filter media, it is necessary to use electrolytic manganese dioxide blocks peeled from the electrode or natural It has been proposed to coarsely crush manganese dioxide and size it to an appropriate particle size, or to mold it using an inorganic binder such as alumina cement as a binder for manganese dioxide powder. has the disadvantage of a small reaction area. On the other hand, when molded with an inorganic binder, the active manganese dioxide surface is covered with the binder, so
It has the disadvantage that its water purification effect is lower than that of manganese-impregnated zeolite.

The present invention was made to solve these problems, and aims to provide a filter medium for water purification that efficiently and economically removes manganese, iron, and coloring from raw water such as lake water and river water. .

The present inventors examined each of the deficiencies of conventionally used filter media one by one, and as a result of various research, discovered a filter material with excellent ability to remove coloring, manganese, and iron from raw water using a method different from conventional methods. This is what led to this.

In other words, the filter medium of the present invention is made macroscopically porous and strong without using a binder by immersing manganese dioxide powder in an acidic solution such as sulfuric acid containing divalent manganese ions and/or magnesium ions. After obtaining manganese dioxide lumps, they are roughly crushed and sized to an appropriate particle size, and then neutralized with a neutralizing agent such as caustic soda, which can be used not only to remove manganese and iron but also to remove coloring. A filter medium for water purification that exhibits high performance can also be obtained.

In the present invention, the time during which manganese dioxide is immersed in the above-mentioned acidic solution and the temperature of the solution are important points; the temperature of the solution should be as high as possible below the boiling point of the solution, and the longer the immersion time It is also preferable in terms of strength. Further, in the present invention, the agglomerates are sized to an appropriate particle size, and the particle size is not particularly limited, but is preferably about 20 to 48 mesh.

Electrolytic manganese dioxide is originally extremely porous microscopically, but as a filter medium for water purification it is better to be macroscopically porous rather than microscopically porous. It is completely inconceivable that manganese dioxide could be endowed with such characteristics by the present invention.

In addition, if an oxidizing agent such as chlorine or potassium permanganate is added to the raw water in combination with the water purification filter medium of the present invention, the color removal ability can be further improved.

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Example 1 A sulfuric acid acidic bath containing 20 g/l of divalent manganese ions and 100 g/l of sulfuric acid was heated to 90°C, manganese dioxide was added to this solution, and the solution was left to stand for 3 days while maintaining the temperature of the solution at 90°C. By this process, strong manganese dioxide lumps are created.

This lump was coarsely crushed and sized into 20 to 48 mesh pieces. Furthermore, in order to deoxidize, it was first washed with water, and then neutralized with caustic soda.

An electron micrograph of the water purification filter material thus obtained is shown in FIG. As shown in FIG. 1, the water purification filter medium of the present invention is macroscopically porous.

Example 2 and Comparative Examples 1 to 3 A filter medium for water purification obtained in Example 1 (Example 2), a filter medium formed by molding electrolytic manganese dioxide conventionally used as a filter medium with Portland cement (Comparative Example 1), A filter medium prepared by coarsely crushing and sizing manganese dioxide (Comparative Example 2) and a manganese-impregnated zeolite (Comparative Example 3) were used to compare the performance of removing chromaticity.

The test conditions were to fill a column with 100 c.c. of each filter medium and use raw water that had been adjusted to a chromaticity of 40 degrees using nitrofumic acid.
Water was passed at a rate of 1000c.c./hour. The second result is
As shown in the figure. This measurement method is generally accepted as a method for determining the overall ability to remove manganese, iron, and coloring from water.

As shown in Figure 2, the water purification ability was highest in Example 2 using the water purification filter medium of the present invention, followed by Comparative Example 3 using manganese adsorbed zeolite, and filter medium using coarsely crushed and sized electrolytic manganese dioxide. Comparative Example 2, which used a filter medium made of electrolytic manganese dioxide molded with Portland cement, and Comparative Example 1, which used a filter medium made of electrolytic manganese dioxide molded with Portland cement. Comparative example 3 with excellent performance
was about 3 days, whereas in Example 2 it was about 6 days, which shows that the water purification filter medium of the present invention has significantly superior water purification ability compared to conventional filter media. In addition,
The PH value of the treated solution was almost the same as that of the raw water.

Example 3 and Comparative Example 4 The water purification filter medium used in Example 2 and the filter medium (manganese impregnated zeolite) used in Comparative Example 3 were used to compare performance in removing manganese. The raw water containing divalent manganese ions and divalent iron ions was adjusted to 5 ppm and 5 ppm, respectively, and the measurement method was the same as in Example 2.

As a result, the residual manganese was 0.3ppm, which is the water quality standard.
Comparing the total amount of water processed to reach the amount of water, the one using manganese-impregnated zeolite (Comparative Example 4) is about 20
On the other hand, the one using the water purification filter material of the present invention (Example 3) had a value of about 300, clearly confirming the superiority of the water purification filter material of the present invention not only in terms of chromaticity but also in terms of manganese removal ability. Ta. Regarding iron, it was not detected until residual manganese reached 0.3 ppm.

Example 4 A filter medium for water purification (Example 4) and Example 1 made in the same manner as in Example 1 using a sulfuric acid acidic solution containing 20 g of divalent manganese ions, 10 g of magnesium ions, and 100 g of sulfuric acid. Using the water purification filter material (Example 2) obtained in Example 2, the performance of color removal was compared using the same test method as in Example 2. The results are shown in Figure 3.

As shown in Figure 3, the water purification capacity is as follows:
Example 4 is superior to Example 2, and the time required to exceed 5 degrees of chromaticity, which is the water quality standard, is longer than that of Example 2.
was 6.1 days, whereas in Example 4 it was 6.6 days, indicating that the water purification ability was improved by adding magnesium ions to the sulfuric acid acidic solution containing divalent manganese ions.

Example 5 A filter medium for water purification (Example 5) made in the same manner as in Example 1 using an acidic sulfuric acid solution containing 10 g of magnesium ions and 100 g of sulfuric acid and Example 1
Using the filter medium for water purification (Example 2) obtained in Example 2, the performance of color removal was compared using the same test method as in Example 2.

In terms of water purification ability, Examples 2 and 5 were almost the same.

As explained above, manganese dioxide powder is
The filter medium for water purification of the present invention, which is obtained by sizing after being immersed in an acidic solution in which valent manganese ions and/or magnesium ions coexist, has extremely high water purification ability and is economically inexpensive.
It is ideal as a filter medium for removing manganese, iron, and coloring from lake water, river water, etc.

[Brief explanation of the drawing]

Figure 1 is an electron micrograph showing the surface condition of the manganese dioxide filter medium according to the present invention, Figure 2 is a graph showing the relationship between the chromaticity of treated water and the number of days elapsed in Example 2 and Comparative Examples 1 to 3; Figure 3 is a graph showing the relationship between the chromaticity of treated water and the number of days elapsed in Examples 2 and 4.

Claims (1)

[Claims] 1 Manganese dioxide powder is immersed in an acidic solution containing divalent manganese ions and/or magnesium ions to form macroscopically porous lumps, and then sized to an appropriate particle size. Filter media for water purification.