JP2001219055A - Method for preparing adsorbent and adsorbent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for simply and inexpensively preparing an adsorbent for effectively adsorption removing a very small amount of an inorganic compound existing in the water to be treated in water treatment by utilizing sludge produced by water treatment and to obtain an adsorbent excellent in adsorptivity by using the method. SOLUTION: The inside of a cylinder 1 having a nozzle 2 where sludge discharging holes 3 are formed is filled with the aluminum salt-containing sludge 5 generated at the water treating step. The sludge 5 packed inside the cylinder 1 is compressed and discharged through the nozzle 2. The discharged sludge 5 is sheared and formed into a specified shape to obtain the objective adsorbent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an adsorbent for inorganic compounds in water, and more particularly to a method for producing an adsorbent used in the field of water treatment such as water purification, river water treatment, groundwater treatment, and sewage treatment.

[0002]

2. Description of the Related Art Conventionally, in the water purification treatment of river water in a water purification plant, a coagulation and sedimentation treatment of turbidity or the like is performed by using a coagulant made of an aluminum compound, and then a filtration treatment by sand filtration is performed. . Further, in the wastewater treatment, treatment with activated sludge is often used. In water treatment such as water purification treatment and wastewater treatment, with the recent deterioration of the water environment, the sophistication of the water treatment is required,
Removal of trace dissolved components in water, for example, inorganic compounds such as heavy metals, pesticides, nitrogen compounds, and phosphorus compounds, is required, and adsorbents are often used to remove them.

On the other hand, in recent years, as the quality of river water and lakes, which are raw water in water treatment, has deteriorated, the amount of coagulant injected has increased, and the scale of water treatment has increased. Has become a very large problem. Sludge generated by water treatment cannot be treated simply by waste treatment, and reuse and effective use of sludge are being studied. Under such circumstances, an adsorbent using sludge generated in water treatment as a raw material has been proposed as an adsorbent for inorganic compounds.

[0004]

Among the sludges generated in the water treatment, the sludge generated in the water purification treatment, in particular,
It is said that the ability to adsorb inorganic compounds such as phosphorus is high. This is because the settled sludge generated in the water purification treatment contains a considerable amount of aluminum, and this aluminum contributes to the adsorption of inorganic compounds. As such an adsorbent using purified water sludge as a raw material,
There is a method for producing an adsorbent for drying and pulverizing purified water sludge as described in 13693, sintering it at about 1000 ° C., and then impregnating with alumina sol to form a γ-Al ₂ O ₃ film. However, the adsorbent obtained by this method, although showing good adsorption performance, in production,
First, a process of drying and pulverizing sludge is required, and there is a problem that it takes a very complicated process and time to dry and pulverize sludge containing a large amount of water. Further, in this method, the adsorbent is not formed into a specific shape, and the size and shape of the adsorbent cannot be selected. Further, in this production method, sintering is performed at 1000 ° C. or lower. For example, in order to burn and reduce the amount of organic substances in sludge to make the sludge porous, sintering at a higher temperature is required.

Japanese Patent Application Laid-Open No. 9-10762 discloses that
A phosphorus adsorbent for kneading and granulating purified water sludge, cement and superabsorbent polymer is mentioned. However, in such a production method, there is a problem that the cost is high because an expensive superabsorbent polymer is used, and the particle size of the adsorbent is as large as 8 to 12 mm, so that the adsorbent is porous. However, there is a problem that the specific surface area is relatively small and the adsorption efficiency is inferior. Also in this method, the shape of the adsorbent is a spherical granular nodule, and the shape cannot be particularly selected.

As described above, the conventional method for producing an adsorbent is
Problems such as complex, many processing steps, high cost,
There was a problem that the size and shape of the adsorbent could not be selected, and the adsorption rate of the adsorbent was low.

The present invention has been made in view of the above circumstances, and utilizes an adsorbent capable of effectively adsorbing and removing a trace amount of an inorganic compound present in water to be treated in water treatment using sludge generated in the water treatment. In addition, it is an object of the present invention to provide a method for producing the composition easily and at low cost, thereby obtaining an adsorbent having good adsorptivity.

[0008]

The gist of the method for producing an adsorbent of the present invention is as follows. In the method for producing an adsorbent of the present invention, a sludge containing an aluminum salt generated in a water treatment process is filled in a cylinder having a nozzle having a sludge discharge hole formed therein, and the sludge filled in the cylinder is filled. It is characterized in that it is discharged from the nozzle by pressurization, and the discharged sludge is sheared and molded. At this time, it is desirable that the sludge is a dewatered cake in which the amount of water generated in the water treatment process is 20 to 97%. Further, it is desirable cross-sectional area at the side of the nozzle cross-section the sludge of the sludge discharge hole is discharged is 0.001mm ² ~50mm ^2. Further, it is desirable that the above-mentioned sludge is filled in a cylinder, the sludge is directly pressurized by a plunger or a screw, and is discharged from a nozzle.

Further, in the method for producing an adsorbent according to the present invention, sludge generated in a water treatment process is filled in a cylinder having a nozzle having a sludge discharge hole, and the sludge filled in the cylinder is filled. It is characterized in that it is discharged from the nozzle by pressurization, the discharged sludge is sheared, molded, and then sintered to form a porous body. The adsorbent of the present invention is characterized by being produced using the method for producing an adsorbent, and is excellent in adsorbing inorganic compounds.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. In the method for producing an adsorbent of the present invention, sludge generated in a water treatment process is used as a raw material of the adsorbent. This sludge is mainly generated by water treatment at a water purification plant, and uses sludge accumulated in a sedimentation pond of each water purification plant or sludge filtered and concentrated by sand filtration. In particular, this sludge is a sludge obtained when using a coagulant of an aluminum salt such as polyaluminum chloride or aluminum sulfate when coagulating and precipitating turbidity in raw water in water treatment at a water purification plant. It is desirable. In recent years, the coagulant of the aluminum salt is used in the water treatment of many water purification plants, and thus such sludge can be easily obtained at the water purification plant. In the case of sludge containing such an aluminum salt, aluminum contained in these sludges contributes to adsorption of inorganic compounds such as phosphorus and arsenic, and thus can be used as an adsorbent.

The sludge preferably has a water content of 20 to 97%. Within such a range, when the sludge is extruded from the nozzle and molded, the sludge discharged from the nozzle does not flow out and has a hardness that maintains a columnar shape, and the sludge after discharge is determined. The form can be maintained, and the fluidity when the sludge is put into the container and pushed out can be secured.

It is preferable to use a dewatered cake as the sludge having a water content of 20 to 97%. This dewatered cake is sludge from which water has been removed, most of which are 20 to
It has a water content of 97%. Normally, purified water sludge contains a large amount of water, and in the case of concentrated sludge from raw water, the water content is often about 99%. However, many water treatment plants remove sludge water to reduce the amount of generated sludge disposal, and treat concentrated sludge as a dewatered cake. Can be easily obtained. If such a dewatered cake is used, the step of adjusting the water content of the sludge is not required, and the adsorbent can be easily formed.

In the method for producing an adsorbent of the present invention, first, the above-mentioned sludge is collected from a water purification plant, and is filled in a cylinder with a nozzle. The shape and material of the cylinder are not particularly limited as long as the cylinder has a cylindrical structure and has a nozzle at an end of the cylinder. FIG. 1 shows an example of the cylinder. The cylinder 1 shown in FIG. 1 has a cylindrical shape,
A nozzle 2 is provided at one end thereof.
Are formed to penetrate therethrough.
FIG. 2 shows another example of the above-mentioned cylinder, in which one end of a cylindrical cylinder 11 has sludge discharge holes 13, 13.
.. Have a plurality of nozzles 12 formed therein.

The number of the sludge discharge holes 3, 3,... (13, 13,...) Formed in such a nozzle is one,
There may be more than one. Also, sludge discharge holes 3 and 13
The cross-sectional shape is not particularly limited, but may be any shape such as a circular shape as shown in FIG. 1, a square shape as shown in FIG. 2, other polygons, and a star shape. Further, in order to improve the surface area of the obtained adsorbent, cylinder 1,
The sludge discharge holes 3 and 13 of the nozzle 11 and the nozzles 2 and 12 may be formed in a donut shape so that the resulting adsorbent can be formed into a hollow cylindrical shape. Thus, by changing the shape of the sludge discharge holes 3 and 13, the shape of the adsorbent can be freely designed.

The discharge portions 3a, 1 of the sludge discharge holes 3, 13
The cross-sectional area of 3a is arbitrary, but 0.001 mm
^Two~ 50mm^TwoIs preferably within the range. 0.001
mm ^TwoIf it is less than 10 mm, the sludge passes through the sludge discharge holes 3 and 13.
The resistance when passing through is increased, making it difficult to discharge sludge.
High stress is required, and clogging is likely to occur.
You. Also 50mm^TwoIf larger, the molded suction
Adhesive becomes too bulky, lowering packing ratio in columns, etc.
Doing so would be inconvenient. Also, multiple nozzles 2 and 12
When the individual sludge discharge holes 3 and 13 are provided, the sludge discharge holes
It is preferable that the shapes of 3, 13 are uniform. like this
In this case, the shape of each particle of the adsorbent to be molded is uniform.
And their performance can be made uniform.

The sludge discharge holes 3, 3 may have any shape in the longitudinal section. For example, it may be a straight tube like the sludge discharge hole 3 as shown in FIG. 3, or may have a sleeve-like vertical cross-sectional shape as the sludge discharge hole 23 in FIG. Further, when the vertical cross-sectional shape of the sludge discharge hole 23 as shown in FIG. 4 is sleeve-shaped, the sludge is discharged more than the hole diameter a on the side where sludge is injected, in view of the fluidity of the sludge. Is preferably made smaller.

Using such cylinders 1 and 11, the above-mentioned sludge is injected and filled into the ends of the cylinders 1 and 11 where the nozzles 2 and 12 are not formed, and the sludge is injected. The cylinder is pushed out from the sludge discharge holes 3 and 13 of the cylinders 1 and 11 by applying pressure to the nozzle side from the side where it was made. As a method of pressurizing the sludge filled in the cylinders 1 and 11 at this time, any method may be used, but a method of directly extruding the sludge with a plunger or a screw is preferable. Can be

FIG. 5 shows a method of discharging and forming the sludge 5 from the nozzle 2 by filling the cylinder 1 with the sludge 5 and moving the plunger 4 in the nozzle direction and pressurizing the same. FIG. 6 illustrates a method of filling the sludge 5 in the cylinder 1, feeding the sludge 5 while pressing the screw 14 in the direction of the nozzle 2 while rotating the screw 14, and discharging the sludge 5 from the nozzle 2 to form the sludge 5. is there. At this time, a method in which the screw 14 rotates while moving in the direction of the nozzle 2 may be used.

Next, nozzles 2 of cylinders 1 and 11
The columnar or rod-shaped sludge 5 discharged from 12 is cut into a predetermined length. The length of the cut of the sludge 5 is not particularly limited, but is preferably in the range of 0.1 to 30 mm from the accuracy of the length and the bulkiness of the adsorbent. As a method of cutting the discharged sludge 5, as shown in FIG. 7, a method of cutting with a blade 6 immediately after the sludge discharge hole 3, a method of separately cutting a rod-shaped product, and the like. No. In this way, by cutting the sludge discharged to the desired length and adjusting the size of the adsorbent, uniform filling can be achieved when filling in columns, etc., and even when dispersed in water and used. Dispersion can be achieved.

The product formed by extruding the sludge 5 can be used as it is by being brought into contact with the water to be treated as an adsorbent. Further, by sintering the formed adsorbent at a high temperature, the adsorbent can be made porous. In this way, if the porous material is made porous, the surface area of the adsorbent becomes large, and the adsorbing performance can be further improved. The sintering temperature at this time is not particularly limited, but is from 1050 to 180
A range of 0 ° C. is preferred. At temperatures below 1050 ° C.
If the ignition loss of the organic matter is not sufficiently achieved, and the temperature is higher than 1800 ° C., it is difficult to uniformly sinter the molded article in the furnace. In addition, the time required for porosification varies depending on the size of the adsorbent and the amount of organic substances present, such as when sludge contains some organic substances and the organic substances are made porous by reducing the ignition loss. Therefore, the sintering time may be appropriately adjusted depending on the conditions, and is not particularly limited.

According to such a method for producing an adsorbent, an adsorbent of an inorganic compound can be easily produced at low cost from sludge generated in a water purification plant without going through complicated steps. Further, the adsorbent can be easily formed into a desired shape. Further, by sintering the obtained adsorbent, the adsorbent can be made porous, and an adsorbent having higher adsorption performance can be obtained.

In addition, the adsorbent obtained by such a production method has a characteristic of adsorbing organic substances, phosphorus compounds, arsenic compounds and the like existing in water, and can particularly adsorb arsenic compounds efficiently. When the arsenic compound in water is adsorbed and removed using this adsorbent, the adsorbent according to the present invention may be dispersed in a tank storing the water to be treated, or the adsorbent may be filled in a column or a tower, A method in which the water to be treated is brought into contact with the column or the like by a method such as passing the water is used.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments. Example 1 An adsorbent was produced by the method shown in FIG. The cylinder 1 has a cylindrical shape, and a nozzle 2 is provided at an end thereof.
Are formed with seven cylindrical sludge discharge holes 3, 3... First, as sludge 5, a dewatered cake (water content 45%, aluminum content 2
1.5 kg (3% -dry solids ratio) was collected, and the dehydrated cake was filled in the cylinder 1. Then, the dewatered cake filled in the cylinder 1 is pressurized with the plunger 4 from the side opposite to the side where the nozzle 2 is located,
The dewatered cake was extruded from the sludge discharge holes 3 of the nozzle 2. Next, the discharge ports 3a, 3a of the sludge discharge holes 3, 3,...
Then, cut out the activated cake to a length of 2 mm with a blade 6
To obtain an adsorbent. The resulting adsorbent was of uniform size.

Example 2 The molded product (adsorbent) produced in Example 1 was further sintered in an electric furnace at 1300 ° C. for 2 hours to obtain a porous adsorbent.

1. Adsorption test An arsenic compound was adsorbed using the adsorbents of Examples 1 and 2. Arsenic (V) concentration 100 μg / L, pH 7
Of the adsorbent of Example 1 or Example 2 was dispersed in 100 ml of an aqueous solution of the above, and the mixture was convected at room temperature for 3 hours while stirring with a propeller. After 3 hours, the stirring was stopped, and the arsenic concentration of the supernatant was measured.
μg / L, and 4.2 μg / L for the adsorbent of Example 2. From these results, it was found that the adsorbents of Example 1 and Example 2 had excellent adsorption performance of arsenic compounds in water.

[0026]

The method for producing an adsorbent according to the present invention uses the sludge generated at a water purification plant, which can be obtained at a low cost, and simply pressurizes, extrudes, cuts and forms the sludge to easily adsorb inorganic compounds. Agents can be manufactured. In addition, in this production method, it is not necessary to particularly dry or pulverize the sludge obtained from the water purification plant when supplying it to the molding, and the sludge generated in the water purification plant is directly subjected to the molding process without any modification. It is possible.

In the above method for producing an adsorbent, the sludge used as a raw material has a water content of 20 to 97 at a water purification plant.
% Of the dewatered cake, it is possible to easily and inexpensively obtain an adsorbent having a high adsorption performance of the adsorbed inorganic compound without adjusting the water content of the sludge. In the manufacturing method of the adsorbent, the use of the cylinder cross-sectional area at the side of the nozzle cross-section the sludge of the sludge discharge hole is discharged is 0.001mm ² ~50mm ^2, it can be extruded easily sludge from the cylinder, The molding of the adsorbent can be easily performed. In the method for producing the adsorbent, if a method of directly pressing sludge with a plunger or a screw is used as a method of pressing the sludge filled in the cylinder, the sludge can be easily extruded from the sludge discharge hole and molded. Can be.

Furthermore, the surface area of the adsorbent can be increased by sintering and making the adsorbent obtained by the above-mentioned method for producing an adsorbent, and the adsorbability of the inorganic compound can be further improved. Can be. Further, since the adsorbent of the present invention is obtained by the above-described method for producing an adsorbent, the adsorbent has a uniform shape and a large surface area, and thus has high adsorption performance for inorganic compounds. Therefore, if used in various water treatment, trace dissolved components in water, for example, heavy metals,
It can remove inorganic compounds such as pesticides, nitrogen compounds, and phosphorus compounds, and can respond to sophistication of water treatment.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing an example of a cylinder used in the present invention.

FIG. 2 is a schematic perspective view showing an example of a cylinder used in the present invention.

FIG. 3 is a longitudinal sectional view showing an example of a shape of a hole of a nozzle used in the present invention.

FIG. 4 is a longitudinal sectional view showing an example of a shape of a hole of a nozzle used in the present invention.

FIG. 5 is a schematic cross-sectional view showing an example of a method of extruding sludge by pressing with a plunger.

FIG. 6 is a schematic cross-sectional view showing an example of a method of pressing and extruding sludge with a screw.

FIG. 7 is a schematic sectional view showing an example of a method of cutting the discharged sludge with a blade.

[Explanation of symbols]

 1, 11 ... cylinder 2, 12 ... nozzle 3, 13 ... sludge discharge hole 4 ... plunger 14 ... screw 5 ... sludge 6 ... blade

Claims (6)

[Claims] 1. A method according to claim 1, wherein a sludge containing an aluminum salt generated in a water treatment process is filled in a cylinder having a nozzle having a sludge discharge hole, and the sludge filled in the cylinder is pressurized. A method for producing an adsorbent, which comprises discharging the discharged sludge from a nozzle, shearing the discharged sludge, and molding. 2. The method for producing an adsorbent according to claim 1, wherein a dewatered cake having a water content of 20 to 97% obtained in a water purification plant is used as the sludge. 3. A cross-sectional area of the sludge discharge hole in a cross section of a nozzle on a side where sludge is discharged is 0.001 mm ^{2 to} 50 m.
The method for producing an adsorbent according to claim 1, wherein m ² is m ² . 4. The adsorbent according to claim 1, wherein the sludge is filled in a cylinder, the sludge is directly pressurized by a plunger or a screw and discharged from a nozzle. Production method. 5. A method for producing an adsorbent, comprising sintering the adsorbent obtained by the method for producing an adsorbent according to claim 1 to form a porous body. 6. An adsorbent produced by the method for producing an adsorbent according to any one of claims 1 to 5.