JP3486935B2 - Method for oxidation treatment of sulfide in aqueous solution - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for oxidizing sulfide in an aqueous solution. The oxidation treatment method of the present invention is applied to wastewater containing sulfides such as hydrogen sulfide and mercaptan, for example, wastewater discharged from sewage treatment plants, sewage pipelines, building pits, etc. It can be used as a pollution prevention technology to prevent corrosion.

[0002]

2. Description of the Related Art Wastewater discharged from sewage treatment plants, sewage pipelines, building pits, etc., has a bad odor because it contains hydrogen sulfide produced by sulfate-reducing bacteria under anaerobic conditions. Also, under aerobic conditions, hydrogen sulfide is oxidized to sulfuric acid, which causes erosion of concrete.

By the way, Japanese Patent Publication No. 39-1015 discloses a gas containing hydrogen sulfide characterized in that a naphthoquinone derivative which has been made water-soluble by introducing an acidic group is dissolved to form an aqueous solution, which is used as an absorbing solution. Desulfurization methods are described. Further, Japanese Patent Application Laid-Open No. 50-36649 describes a deodorant utilizing the above water-soluble naphthoquinone derivative as a deodorant (deodorant) for malodor caused by mercaptans, thiols, hydrogen sulfide and the like. There is. All of these techniques utilize an oxidation reaction by a naphthoquinone derivative.

[0004]

However, when applied to wastewater containing sulfides to prevent pollution, the use of the above water-soluble naphthoquinone derivative causes secondary pollution by the naphthoquinone derivative dissolved in the wastewater. (COD
Increase). The present invention has been made in view of such circumstances, and an object thereof is to provide a method for oxidizing a sulfide in an aqueous solution, which avoids the problem of secondary contamination of the treated water.

[0005]

Means for Solving the Problems As a result of intensive studies by the present inventors in order to achieve the above-mentioned object, naphthoquinonesulfonic acid was found to be quinone-type even if water-insoluble by chemically bonding to an anion exchange resin. It was found that not only the oxidative action based on the above but also the oxidizable ability for regeneration from hydroquinone type to quinone type does not change at all.

The present invention has been completed based on the above findings, and the gist thereof is that an aqueous solution containing a sulfide at a concentration of 1000 ppm or less is chemically bonded to an anion exchange resin. A method for oxidizing sulfides in an aqueous solution is characterized by contacting naphthoquinonesulfonic acid with oxygen.

The present invention will be described in detail below. The gist of the present invention is to use naphthoquinone sulfonic acid chemically bonded to an anion exchange resin as a redox agent.

In the present invention, the naphthoquinone sulfonic acid used as a raw material for the redox agent is not particularly limited, and for example, various naphthoquinone sulfonic acids represented by the following general formula [I] or [II], or The alkali metal salt, alkaline earth metal salt or ammonium salt can be used.

[0009]

[Chemical 1]

In the above general formula, X is --H, --O.
_{H, -NH 2, -SH, -CN} , -SCN, -SO
₃ H, COOH, -X (halogen atom), -R, -O
R, -NHR, -NRR ', - SO 2 R, represents a -COOR. However, R shows a C1-C6 linear or branched alkyl group.

Specific examples of the naphthoquinone sulfonic acid represented by the above general formula are typically 1,4-naphthoquinone-2-sulfonic acid, 1,4-naphthoquinone-2,
Examples thereof include 3-disulfonic acid, 2-methyl-1,4-naphthoquinone-3-sulfonic acid and 2-hydroxy-1,4-naphthoquinone-3-sulfonic acid.

Among the above naphthoquinone sulfonic acids,
1,4-naphthoquinone-2-sulfonic acid (or the corresponding salt) is preferred. That is, 1,4-naphthoquinone-
2-sulfonic acid or a salt thereof is industrially available at low cost, and the redox agent obtained from it is excellent in stability in an aqueous solution containing a sulfide, and therefore 1,4-
The elution of naphthoquinone-2-sulfonic acid itself is maximally prevented. Then, 1,4-naphthoquinone-2-sulfonic acid is directly produced as a hydroquinone type salt by an addition reaction of a sulfite salt (sodium salt or ammonium salt). 1,
It is particularly preferred to use it as a 4-naphthoquinone-2-sulfone salt.

The anion exchange resin, which is another raw material for the redox agent, has a chemical structure in which an anion exchange group is introduced into a water-insoluble resin matrix, and the type and physical structure of the matrix and the type of exchange group are used. Various anion-exchange resins are known by.

In the present invention, the type of anion exchange resin is not particularly limited as long as it can form a stable ionic bond with a sulfonic acid group. However, usually, for example,
A triethylammonium salt, a dimethylethanolammonium salt, or an anion exchange resin having a primary to tertiary amino group introduced into a copolymer particle of styrene and divinylbenzene is used. The structure of the matrix may be either gel type or porous type, and the degree of crosslinking (swelling degree) thereof is not particularly limited.

As the anion exchange resin having a triethylammonium salt, a strong basic anion exchange resin (type I resin) manufactured by Mitsubishi Kasei Co .: SA10A series ("SA10A", "SA12A", "SA11A") is used.
Etc.), PA300 series ("PA306", "PA3
08 "," PA312 "," PA316 "," PA31 "
8 "), an anion exchange resin having a dimethylethanol ammonium salt, a strong basic anion exchange resin (II type resin) manufactured by Mitsubishi Kasei: SA10A series (" SA20A "," SA21A ", etc.), PA400
Series ("PA406", "PA408", "PA4
12 "," PA416 "," PA418 ", etc.), 1 to 3
As the anion exchange resin having a high-grade amino group, a weakly basic anion exchange resin manufactured by Mitsubishi Kasei: "WA
10 "," WA11 "," WA20 "," WA21 ",
"WA30" etc. are mentioned. In the present invention, the anion exchange resin used particularly preferably is the PA300 series porous strongly basic anion exchange resin, and the average particle size thereof is about 300 to 1200 μm.

In the present invention, naphthoquinone sulfonic acid is used by being chemically bonded to an anion exchange resin. The chemical bonding of naphthoquinone sulfonic acid to the anion exchange resin can be easily performed, for example, by adding the anion exchange resin to an aqueous solution of naphthoquinone sulfonate and appropriately stirring. The anion exchange resin may be used in either a wet state or a dry state. The chemical bond amount of naphthoquinone sulfonic acid to the anion exchange resin is not particularly limited and is appropriately selected within the range of the exchange capacity of the anion exchange resin.

The chemical binding of naphthoquinone sulfonic acid to the anion exchange resin may be carried out in the hydroquinone type,
Further, it may be carried out while oxidizing the sulfide with naphthoquinonesulfonic acid in an aqueous solution containing the sulfide.

In the above chemical bond, an ion exchange method mainly consisting of the following reactions (1) to (3) depends on the difference in the anion exchange resin and the salt structure of naphthoquinone sulfonic acid or naphthohydroquinone sulfonic acid. Adopted.

[0019]

[Chemical 2]

The above (1) is a neutralization reaction, (2) is a neutral salt decomposition reaction, and (3) is a metathesis reaction. Strongly basic anion exchange resins are usually marketed in the Cl type, treated with an aqueous NaOH solution and used in the OH type. However, in the present invention, as naphthoquinone sulfonic acid, 1,4
-When using naphthoquinone-2-sulfonate,
Among (2) and (3), it is preferable to adopt the ion exchange method comprising the reaction of (3).

The anion exchange resin chemically bound to naphthoquinone sulfonic acid is collected by filtration and then washed as needed to remove the attached naphthoquinone sulfonic acid and used as a redox agent.

In the present invention, the aqueous solution to be subjected to oxidation treatment, that is, the aqueous solution containing sulfide, typically includes wastewater discharged from a sewage treatment plant, a sewer pipe, a building pit, or the like. To be Since these wastewaters do not contain a large amount of hydrogen sulfide, there is no particular problem even if they are directly subjected to the oxidation treatment of the present invention.

However, in the present invention, an aqueous solution other than the above can be also subjected to the oxidation treatment. In that case, the concentration of the sulfide in the aqueous solution is adjusted to 1000 ppm or less before use . Sulfide concentration in aqueous solution
By adjusting the concentration to 1000 ppm or less, it is possible to obtain an advantage that sulfide can be oxidatively decomposed without depositing colloidal sulfur which is difficult to handle.

In the present invention, the aqueous solution containing sulfide (waste water) and the above-mentioned redox agent are contacted in the presence of oxygen to oxidize and decompose the sulfide. As a contact method,
In the column, a column type in which an aqueous solution is supplied to the packed redox agent to bring them into contact with each other, or, in the vessel, either a tank type in which the redox agent and an aqueous solution containing a sulfide are brought into contact with each other, is usually The tank type is adopted. Further, either a batch type or a continuous type may be used.

In the tank-type contact, conditions such as the usage rate of the redox agent, the residence time of the wastewater and the air supply amount vary depending on the content of naphthoquinonesulfonic acid in the redox agent and the concentration of sulfide in the wastewater. Usually, the use ratio of the redox agent is 0.
01-10% by weight, residence time of waste water is 10-180 minutes,
Air supply is 1 to 1000 ml per liter of wastewater
It is appropriately selected from the range of / minute.

FIG. 1 is an explanatory view showing an example of an oxidation treatment apparatus for carrying out the present invention. The oxidation treatment apparatus shown in FIG. 1 includes a closed tank (3) equipped with a wastewater supply pipe (1) and a processing liquid overflow pipe (2), and an air supply pipe (each connected to an upper space in the closed tank). 4) and the atmosphere communication pipe (5), the circulation pipe (6) for extracting the staying liquid in the closed tank (3) and supplying it to the upper space of the closed tank in a spray state, and the process liquid overflow pipe (2) It is mainly composed of filters (7) and (8) arranged at the overflow port and the retained liquid extraction port of the circulation pipe (6), respectively.

The waste water supply pipe (1) is arranged so as to open in the upper space in the closed tank (3), that is, the internal space formed above the installation position of the processing liquid overflow pipe (2). . Waste water is sucked by the pump (11) and continuously supplied from the waste water supply pipe (1) to the closed tank (3). By changing the opening position of the waste water supply pipe (1), the waste water can be continuously supplied to the wall surface of the upper space in the closed tank (3) or the liquid in the closed tank (3).

The processing liquid overflow pipe (2) is a closed tank (3).
It is located at a position where an internal space of an appropriate volume can be formed on the upper side of the closed tank (3). The treatment liquid which has been treated for a predetermined residence time in the closed tank (3) is continuously withdrawn from the treatment liquid overflow pipe (2).
Reference numeral (31) is a pH meter of the retained liquid in the closed tank (3).

Air is supplied into the closed tank (3) through the air supply pipe (4) by the pump (41). Reference numeral (42) is an air flow meter connected to the air supply pipe (4). The inside of the closed tank (3) is opened to the atmosphere by the air communication pipe (5), and a part of the air supplied into the closed tank (3) is dissolved in the stagnant liquid in the closed tank (3). Is discharged into the atmosphere through the atmosphere conduit (5). The reference numeral (51) is the atmosphere conduit (5).
Is a sulfide concentration meter connected to.

The circulation pipe (6) is arranged between the bottom of the closed tank (3) and the upper space in the closed tank (3),
The accumulated liquid in the closed tank (3) is extracted by a circulation pump (61) arranged in the middle of the circulation pipe (6) and is supplied in a spray state to the upper space in the closed tank (3). Reference numeral (62) is a valve provided on the side of the retained liquid withdrawing port of the circulation pipe (6) for controlling the amount of circulating liquid, and reference symbol (63) is at the tip of the supply port of the circulation pipe (6). It is a spray nozzle provided.

The filters (7) and (8) have a function of holding a redox agent (not shown) previously stored in the closed tank (3) in the closed tank. Therefore,
The size of the openings of the filters (7) and (8) is set to an appropriate size so that the redox agent does not leak.

In the oxidation treatment apparatus shown in FIG. 1, the waste water continuously supplied from the waste water supply pipe (1) to the closed tank (3) and the redox agent previously stored in the closed tank (3) are brought into contact with each other to remove air. Air continuously supplied from the supply pipe (4) to the closed tank (3) and the accumulated liquid supplied in a spray state to the upper space of the closed tank (3) through the circulation pipe (6) are brought into contact with each other.

The air supply into the closed tank (3) is controlled in a small amount so as not to cause leakage of sulfide from the atmosphere conduit (5), but the upper space of the closed tank (3). Since the contact efficiency of the circulating stagnant liquid sprayed with the air is high, it is possible to dissolve a sufficient amount of air (oxygen) in the stagnant liquid in the closed tank (3).

In continuous operation for a long period of time, naphthoquinone sulfonic acid is gradually eluted from the anion exchange resin constituting the redox agent, and the oxidation treatment ability of the redox agent decreases. In such a case, the oxidation treatment ability of the redox agent is restored by supplying naphthoquinone sulfonic acid or its salt or naphthohydroquinone sulfonic acid or its salt into the closed tank (3) and chemically bonding them to the anion exchange resin. Can be done. Aqueous solutions such as naphthoquinone sulfonate are stored in tank (9), valve (91),
It is supplied into the closed tank (3) through a pump (92) and a pipe (93).

[0035]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

<Synthesis of redox agent> The compound has a triethylammonium salt as a functional group and has an exchange capacity of 0.8 meq /
ml, strongly basic anion exchange resin having a particle size range of 300 to 1180 μm (“PA306A” Cl manufactured by Mitsubishi Kasei Co., Ltd.)
Type) and 1,4-naphthoquinone-2-sulfonic acid sodium salt were used to synthesize a redox agent. First, 1,4
-0.5 of naphthoquinone-2-sulfonic acid sodium salt
The above anion exchange resin 1 in 400 parts by weight of an aqueous solution of 1% by weight
00 parts by volume was added and the mixture was stirred at room temperature. Next, the anion exchange resin was collected by filtration, and then washed sufficiently with water to remove 1,4-naphthoquinone-2-sulfonic acid attached to the anion exchange resin.

Example 1 The oxidation treatment apparatus shown in FIG. 1 (the capacity of the treatment liquid overflow pipe (2) in the closed tank, which is equal to or less than 2 liters) was used. The redox agent was stored in the closed tank (3) so that the concentration of naphthoquinonesulfonic acid in the staying liquid was 100 ppm, and the hydrogen sulfide ion (SH ⁻ ) concentration was 100 from the wastewater supply pipe (1).
Waste water of ppm is continuously supplied to the upper space in the closed tank (3), and 100 ml / min of air is continuously supplied to the upper space in the closed tank (3) from the air supply pipe (4). The circulating pump (61) sprayed the retained liquid extracted from the bottom of the closed tank (3) from the spray nozzle (63). 100 on the filters (7) and (8)
A mesh wire mesh was used. The residence time was changed, the hydrogen sulfide ion concentration in the treatment liquid discharged through the treatment liquid overflow pipe (2) was measured, and its change with time was determined. The result is shown in Figure 2.
Shown in. In FIG. 2, the vertical axis represents the hydrogen sulfide ion (SH ⁻ ) concentration (p ⁻ ) in the processing liquid discharged through the processing liquid overflow pipe (2).
pm), the horizontal axis represents the throughput (L), and the symbol (θ _T ) represents the residence time (Hr).

As is clear from the results shown in FIG. 2, when the residence time is 2 hours, the hydrogen sulfide ion concentration in the treatment liquid is substantially zero, and the hydrogen sulfide ion concentration has an oxidation rate of 100%.
Is. The nitrogen supply zone shown in FIG. 2 is a case where nitrogen is supplied instead of air supply, but the oxidation of the hydrogen sulfide ion concentration is not effectively performed in the absence of oxygen. However, it can be seen that after that, by switching to the supply of air, the oxidation of the hydrogen sulfide ion concentration has started. The supply amount of air or nitrogen in each zone is 100 ml / min.

During the above continuous treatment, 1,4-naphthoquinone-2-sulfonic acid and 1,4 in the treatment liquid were added.
-As a result of measuring naphthohydroquinone-2-sulfonic acid and checking for its elution, 1,4 from the redox agent was obtained.
-Elution of naphthoquinone-2-sulfonic acid and 1,4-naphthohydroquinone-2-sulfonic acid was not observed.

[0040]

According to the oxidation treatment method of the present invention described above, the use of naphthoquinone sulfonic acid which has been chemically bound to an anion exchange resin to render it water-insoluble prevents the elution of naphthoquinone sulfonic acid, and the sulfide in the aqueous solution. Can be effectively oxidized to prevent foul odor and corrosion. Therefore, the oxidation treatment method of the present invention is particularly effective as a pollution control technique.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an example of an oxidation treatment apparatus for carrying out the present invention.

FIG. 2 is a graph showing the results of continuous oxidation treatment of the sulfide obtained in Example 1.

[Explanation of symbols]

1: Waste water supply pipe 2: Processing liquid overflow pipe 3: Closed tank 4: Air supply pipe 5: Atmosphere conduit 6: Circulation piping 7: Filter 8: Filter

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A 61-4522 (JP, A) JP-A 56-81137 (JP, A) JP-A 54-99343 (JP, A) JP-A 52- 68071 (JP, A) JP 51-6359 (JP, A) JP 50-145367 (JP, A) JP 49-43871 (JP, A) JP 49-43447 (JP, A) JP-A-49-15248 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C02F 1/72 ZAB

Claims (3)

(57) [Claims] 1. A sulfide in an aqueous solution, characterized in that an aqueous solution containing a sulfide at a concentration of 1000 ppm or less is brought into contact with naphthoquinonesulfonic acid chemically bonded to an anion exchange resin in the presence of oxygen. Oxidation treatment method. 2. A naphthoquinone sulfonic acid chemically bonded to an anion exchange resin, which is obtained by a metathesis reaction between a Cl type strongly basic anion exchange resin and 1,4-naphthoquinone-2-sulfonate. The oxidation treatment method according to claim 1, wherein 3. A closed tank (3) having a waste water supply pipe (1) and a processing liquid overflow pipe (2), an air supply pipe (4) and an atmosphere connected to the upper space in the closed tank, respectively. A conduit pipe (5), a circulation pipe (6) for extracting the accumulated liquid in the closed tank (3) and supplying it to the upper space of the closed tank in a spray state, and an overflow port of the process liquid overflow pipe (2). And an oxidation treatment device mainly composed of filters (7) and (8) respectively arranged at the staying liquid outlet of the circulation pipe (6), and from the wastewater supply pipe (1) to the closed tank (3). The continuously supplied wastewater is brought into contact with the redox agent previously stored in the closed tank (3), and the air continuously supplied from the air supply pipe (4) to the closed tank (3) and the circulation pipe (6) are passed through the closed tank. Supplied as a spray to the space above (3) The oxidation treatment method according to claim 1 or 2, wherein the accumulated liquid is contacted.