JPS61101230A - Preparation of waste ozone gas treating material - Google Patents

Abstract

PURPOSE:To dispense with the treatment of waste washing water, by recirculating and passing water containing a manganese salt and chlorine and a solution containing a pH buffer through a fibrous medium, a particulate medium or a filler to enhance the adhesion efficiency of manganese oxide to the surface of the medium. CONSTITUTION:A fibrous medium such as a glass fiber, a particulate medium such as sand or a filler such as a Raschig ring is charged in a contact tank 2 and washed with water. Subsequently, a solution 8 of a manganese salt such as manganese chloride, chlorine water 7 and a pH buffer 6 are mixed to prepare a recirculation liquid which is, in turn, succeedingly recirculated in the order of recirculation liquid inflow pipe 9 contact tank 2 recirculation liquid return pipe 10 recirculation liquid tank 4 by a recirculation pump 5 until Mn<2+> therein exhausted. The prepared waste ozone treating agent is washed and dried to obtain a product.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to the production of a treatment material for waste ozone gas in the ozone treatment of clean water, commercial water, sewage, human waste, industrial wastewater, etc.

[Conventional technology]

The waste ozone gas treatment technologies that have been shown to date include:
Examples include activated carbon method, chemical absorption method, thermal decomposition method, and manganese oxide catalyst method.

In the activated carbon method, returned ozone gas is introduced into a tank filled with activated carbon, and ozone is decomposed using urine according to the following formula. 203+C*-302+C* C*: Activated carbon This method is widely used in the treatment of waste ozone gas because it can efficiently decompose ozone at low concentrations, but its disadvantages include powdering of activated carbon particles and side reactions due to the reaction with ozone. The reduction of activated carbon by being oxidized to carbon monoxide and carbon dioxide,
The dangers of ignition and explosion when coming into contact with high concentrations of ozone are cited.

The chemical absorption method is a method in which waste ozone gas is introduced into a tank containing a reducing agent aqueous solution such as sodium sulfite, sodium thiosulfate, or ferrous salt, or an alkaline aqueous solution such as sodium hydroxide, and is absorbed. This method has drawbacks such as a decrease in the absorption capacity due to the change in the composition of the chemical due to ozone absorption, and the need for replenishment of the chemical and treatment of waste liquid, which is complicated.

The thermal decomposition method is a method in which waste ozone gas is introduced into a combustion chamber for heavy oil, light oil, etc., and thermally decomposed. This method is well implemented when treating waste ozone with a high concentration that poses a risk of explosion when treated with activated carbon, but the disadvantage is that it is expensive. The manganese oxide catalyst method involves injecting waste ozone gas into a tank filled with a catalyst, such as one made by adhering manganese oxide to the surface of sand, or one made by mixing and firing manganese oxide with silica/alumina cell, clay, activated carbon, etc. It decomposes ozone mainly through the following reaction.

203+ MnO2 = 302 + Mn 02 The present invention uses glass, glass,
Concerning a new manufacturing method for waste ozone gas treatment materials, in which manganese oxide is attached to the surface of fibrous media and net-like media such as resins and metals, or granular media such as sand and resins, and fillers such as Mojiku, Raschig Ring, and Terraret. It is.

The conventional method for attaching manganese oxide to the surface of sand is to add several percent solutions of manganese chloride and potassium permanganate to the sand, mix well, wash with water, and repeat this process several times. It is then dried.

As related technology to this application, the Showa 5
There is a 9 year patent application No. 036398.

[Problem that the invention seeks to solve]

In the conventional method, manganese dioxide is produced by the reaction between manganese chloride and potassium permanganate as shown in the following equation, but this reaction occurs specifically only on the sand surface.
+4HCe+2Kc/? However, there were some points that needed to be improved as follows.

(1) Since a large amount of manganese dioxide is produced far from the sand surface, the adhesion efficiency of manganese to the filter medium is poor, and the amount of manganese is only about 20 to 30% of the chemicals used in terms of manganese.

(2) For the same reason, a large amount of washing water is required, and washing wastewater containing a large amount of manganese is generated, which also needs to be treated.

The present invention was developed as a result of repeated research aimed at improving the efficiency of manganese adhesion to the medium and eliminating the need for treatment of cleaning wastewater.

[Means for solving problems]

The chemicals used in the present invention include manganese salts such as manganese chloride, liquid chlorine, chlorine agents such as sodium hypochlorite, and a pH buffer that adjusts the pH to 3 to 8, preferably 5 to 6.5. However, the use of this pH buffer is the most distinctive feature of the present invention.

The present invention solves all of the above problems by using the three types of chemical solutions mentioned above and bringing them into cyclic contact with the medium.

[Effect]

The principle of producing manganese dioxide in the present invention is based on the following two reactions.

Mn2"10Mno2・H2010H2O-MnO2・Mn
0-H20+2H+MnO2・MnO-H3O+ 21
FL! 0+CTo -2Mn 02' H20+2I
(" +2Ce - This reaction can be carried out, for example, by adding Mn to ordinary sand.
''' - (Even if raw water containing chlorine is added to water and passed through it for a long time, the process will gradually progress, resulting in sand with manganese oxide attached to the surface, but it will take a few months to a year.) Because it takes a very long time, a technology that can be manufactured in a short time is required for industrial use.

In order for this reaction to proceed in a short time and to deposit a predetermined amount of manganese, it is necessary to increase the concentration of manganese salt and chlorine agent, but if only manganese salt and chlorine agent are used, the pH will increase due to the production of acid. This is extremely dangerous as it causes the generation of toxic chlorine gas. For this reason, the pH
It is necessary to adjust the pH so that it does not drop too much. However, in the method of simply adding an alkali such as sodium hydroxide to suppress the decrease in −, the oxidation of Mn'+ ions occurs instantaneously at the point where the pH locally becomes high the moment the alkali is added. This is not an appropriate control method because the oxidation of M n 2"4one proceeds throughout the circulating fluid due to the catalytic action of the produced manganese oxide. Therefore,
There is a need for a pH control method that suppresses the flow of water in a manner that does not cause a portion to become even momentarily high in pH. A method that meets this requirement is the use of a pH buffer, which is the most distinctive feature of the present invention.

The main features of the present invention are as follows.

(1) By adding a buffer that can adjust the pH to 3 to 8, preferably 5 to 6.5, the oxidation of M n2'' ions that occurs away from the surface of the medium can be extremely smoothly suppressed; Further, volatilization of chlorine gas due to a decrease in pH can be suppressed to a small amount.

(2) By passing circulating water through a filter medium and filtering it, M
The manganese dioxide hydrate produced by the gradual oxidation of n''4-one can be captured in the medium, and this can be used as a Mn'+ ion oxidation catalyst in the subsequent reaction.

(3) Since most of the oxidation of Mn'' ions can be performed on the medium surface, the adhesion efficiency of manganese can be extremely high.

(4) Mn2 in the circulating fluid is reduced by circulating the fluid.
Ions can be completely removed. Therefore, treatment of washing wastewater is not necessary.

Next, an embodiment of the present invention will be explained based on FIG.
1 is a raw material medium, 2 is a contact tank, 3 is a filter medium support plate, 4 is a circulating liquid tank, 5 is a circulation pump, 6 is a pH buffer tank, 7 is a chlorine water tank, 8 is a manganese salt solution tank, 9 is Circulating fluid inflow pipe, 10
1 is a circulating fluid return pipe, 11 is a backwash drainage outflow pipe, 12 is a tap water inflow pipe, and 13 is a circulating fluid tank drain.

The raw material medium 1 put into the contact tank 2 is backwashed with tap water,
Dirt from the raw material medium is discharged from the backwash drainage outflow pipe 11. Next, in the circulating liquid tank 2, tap water inflow pipe 12, pH buffer tank 6
, water from the chlorine water tank 7 and the manganese salt solution tank 8 and each chemical solution are mixed to reach a pH of 3 to 8, preferably 5.
A circulating fluid adjusted to 6.5 is prepared, and the circulation pump 5
Circulating fluid inflow pipe 9 - contact tank 2 - circulating fluid return pipe 1
It is circulated in the order of o-circulating liquid tank 4. Circulation is M in the circulating fluid.
The process continues until n← is removed, and the produced waste ozonated material is backwashed with tap water, taken out from the contact tank, and dried to form a product.

In addition, injection of pH buffer solution, chlorine water, manganese salt solution,
The injection may be carried out at once, in divided injections, continuous injection or a combination thereof. In addition, in the example shown in Fig. 1, the circulating fluid is passed in a downward flow, but the circulating fluid is passed in an upward flow,
Any horizontal flow is fine.

〔Example〕

An example of manufacturing a waste ozone gas treatment material using glass wool is shown.

Glass wool of 700 trtl in a consolidated state with an inner diameter of 60
It was packed into a U column. The circulating fluid flow rate is LV=IC
II-m/H), 5V = 40 (H'''1), and the total amount of circulating fluid was IOJ.The circulating fluid was pure water, pH buffer,
Add chlorine water to set - to 6.1, and manganese salt solution to 10
W/V %OMn C62.4 H20 solution 1e to 10
The solution was injected in divided doses and circulated. MnC62 used
・4 The total amount of H2O is 1002, the total amount of chlorine water is 40
? It was asc6z.

The production of waste ozone gas treatment material was completed after a contact time of 150 minutes, and the water quality of the circulating fluid was such that there would be no problem even if it was discharged as is, as shown in Table 1.

Table 1 Water quality of circulating fluid at the end of production The amount of manganese deposited on the produced waste ozone gas treatment material is 0.
．． 2f-Mn/? Made of glass wool, MnC used
Most of the manganese in 4.4H20 is attached to the medium.

〔Effect of the invention〕

According to the method of the present invention, the manganese adhesion efficiency, which was conventionally only 20 to 30%, has increased to nearly 100%.In addition, there is almost no need for a cleaning process, no need for drainage treatment, and the time required for production is reduced. This is an extremely effective method in practice, as it has many effects, including significant savings in water consumption.

[Brief explanation of drawings]

FIG. 1 is a flow sheet showing the eleventh embodiment of the present invention. 1... Raw material filter medium, 3... Contact tank, 3... Filter medium support plate, 4... Circulation water tank, 5... Circulation pump, 6...
pH buffer tank, 7... Chlorine water tank, 8... Manganese salt solution tank, 9... Circulating fluid inflow pipe, 10... Circulating water return pipe, 11... Backwash drainage outflow pipe, 12.・・Tap water inflow pipe, 13.・Circulating water tank drain.

Claims (1)

[Claims] 1. Manganese salt solution such as manganese chloride, manganese sulfate, etc.
A solution containing chlorine-containing water and a pH buffer solution such as sodium hypochlorite is applied to fibrous, reticulated and felt media such as glass, resin, metal, or granular media such as sand, resin, or By circulating liquid through a contact tank filled with filler, etc.
A method for producing a waste ozone gas treatment material, which comprises attaching manganese oxide having ozone decomposition ability to the surface of a medium. 2 Adjust the pH of the circulating fluid from 3 to 8 by adding a pH buffer solution.
A method for producing a waste ozone gas treatment material according to the method according to claim 1, wherein the contact with the medium is preferably adjusted to a range of 5 to 6.5. 3. According to the method according to claim 1, characterized in that the manganese salt solution, chlorine-containing water, and pH buffer solution are injected into the circulating fluid simultaneously, separately, continuously, or in divided doses. Method for producing waste ozone gas treatment material.