JP2987892B2 - How to remove dissolved oxygen - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for removing oxygen dissolved in water.
More specifically, the present invention relates to a method for removing dissolved oxygen using a chelate resin having a specific chelating functional group carrying copper.

<Conventional technology> In the chemical industry, for utilities such as heating and cooling,
A large amount of water is used for processes such as absorption, washing, and crystallization. However, when oxygen is present in these waters, corrosion due to dissolved oxygen may occur. Therefore, various methods have been proposed and implemented for removing dissolved oxygen.

For example, a method of adding hydrazine, sodium sulfite, etc. to reduce chemically dissolved oxygen, a method of reducing dissolved oxygen by an ion exchange resin on which reduced copper is deposited, a method of reducing hydrogen in the presence of an ion exchange resin carrying palladium Method for reducing dissolved oxygen by gas [Chemical Industry, 7, 66 (198
5)].

<Problems to be Solved by the Invention> However, in the method of chemically reducing oxygen dissolved in an aqueous solution, the boiler is operated in the case of a boiler feedwater as a result of a slow reduction rate and a large amount of salt being brought into the water to be treated. There are problems such as causing trouble.

Also, in the method of reducing dissolved oxygen by hydrogen gas in the presence of a metal-supported ion exchange resin, it is extremely difficult to handle because the metal ions leak into the processing solution or the hydrogen gas is explosive. There is. In addition, it is difficult to dissolve hydrogen gas in the water to be treated, and an excessively large amount of hydrogen gas must be used.The hydrogen gas dissolved in the treated water must be separated after treatment and before it can be used as water. Complicated operations are required.

An object of the present invention is to provide a method capable of effectively removing dissolved oxygen in water and suppressing contamination of a processing solution with impurities. As a result of intensive studies, the present inventors have found that such objects can be achieved by using a specific chelating resin, and have completed the present invention.

<Means for Solving the Problems> The present invention is to contact a chelate resin having an aminocarboxylic acid group carrying copper and / or an aminoalkylenephosphonic acid group carrying copper with water in which oxygen is dissolved, This is a method for removing dissolved oxygen in water, which comprises adsorbing oxygen to a resin.

The water to be treated in the present invention is water in which oxygen is dissolved, and is not particularly limited. The treated water may contain components other than water as long as the effects of the present invention are not impaired. Generally, boiler feed water, cooling water, washing water and the like can be mentioned.

The chelate resin having a copper-carrying aminocarboxylic acid group and / or a copper-carrying aminoalkylenephosphonic acid group used in the method of the present invention is a chelate resin having an aminocarboxylic acid group and / or an aminoalkylenephosphonic acid group as a functional group. It is obtained by adsorbing a copper compound to a resin and then subjecting the resin to a reduction treatment.

The chelate resin having such an aminocarboxylic acid group and / or an aminoalkylenephosphonic acid group may be any chelate resin that adsorbs a copper compound, and the resin substrate, shape, and production method are not particularly limited, and known methods can be used. Or a commercially available chelate resin can be used.

For example, as a resin having an aminocarboxylic acid group,
Nitrile group, chloromethyl group, sulfonyl chloride group,
Carbonyl chloride group, isocyanate group, epoxy group, aldehyde group, chlorine, bromine, a polymer having an amine-reactive group such as a halogen atom such as iodine ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, Hexamethylenediamine, octamethylenediamine, nonamethylenediamine,
A polyamine such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, hydrazine, guanidine, etc. is reacted to obtain a polyamino resin having two or more primary or secondary amino groups in the molecule, and further, monochloroacetic acid is added to the polyamino resin. , Monobromoacetic acid,
Monochloropropionic acid, a resin having a polyaminocarboxylic acid group obtained by reacting a halogenated alkyl carboxylic acid compound such as monobromopropionic acid or a salt of an alkali metal or an alkaline earth metal thereof, acrylic acid to the polyamino resin, It is obtained by reacting methacrylic acid, acetylenedicarboxylic acid, maleic acid, an alkali metal or alkaline earth metal salt of these acids, or a methyl or ethyl ester of these acids, and in the case of an ester, performing hydrolysis. Examples of the resin include a resin having a polyaminocarboxylic acid group.

Commercially available resins having an aminocarboxylic acid group include Sumichelate MC-75, Sumichelate MC-76, Sumichelate
MC-30 (Sumitomo Chemical Industries, Ltd.), Duolite C-46
6, Amberlite IRC-718 (from Rohm and Haas), Diaion CR-10 (from Mitsubishi Kasei), Levatit TP-207 (from Bayer), Dowex A-
1 (manufactured by Dow Chemical Co., Ltd.), Unicelec UR-10 (manufactured by Unitika), EPORAS MX-8 (manufactured by Miyoshi Oil & Fats Co., Ltd.) and the like.

Further, as the chelating resin having an aminoalkylenephosphonic acid group, the polyamino resin may be an alkylphosphorizing agent such as chloromethylphosphonic acid or chloroethylphosphonic acid, or an alkylating agent such as formaldehyde or trioxymethylene and phosphorus trichloride, Chelate resins having a polyaminoalkylenephosphonic acid group obtained by reacting a phosphorylating agent such as phosphoric acid, hypophosphorous acid, methyl phosphite or ethyl phosphite under an acidic catalyst such as hydrochloric acid or sulfuric acid.

Commercially available chelate resins having an aminoalkylenephosphonic acid group include Sumichelate MC-95 (manufactured by Sumitomo Chemical Co., Ltd.), Duolite C-467 (manufactured by Rohm and Haas), Levatit OC-1060 (manufactured by Bayer), and Uniselec UR-3300 (manufactured by Unitika) and the like.

In particular, a chelating resin having a polyaminocarboxylic acid group or a polyaminoalkylenephosphonic acid group, specifically, a chelating resin in which a carboxylic acid group or a phosphonic acid group is bonded to a polymer main chain via a polyaminoalkylene group, is preferably copper. It is preferably used, since it supports it and has excellent dissolved oxygen removal properties, and very little elimination of copper from the copper-supporting chelate resin.

The copper compound supported on the chelate resin is not particularly limited as long as it is a chelate bond with the chelate resin, but generally, copper halide, copper sulfate,
Copper formate, copper acetate, copper-ammonia complex and the like are used.

The method of supporting copper is not particularly limited, but generally, a so-called batch method in which the chelate resin is charged into an appropriate solvent containing a copper compound and stirred and contacted, or the column is filled with the chelate resin and There is a so-called column flow method in which a solution of the compound is passed. After the complex of the copper compound and the chelate resin is formed by such a method, the copper compound is reduced by a known method using an appropriate reducing agent.

The reducing agent is not particularly limited, but generally, formalin, formic acid, sodium borohydride, lithium aluminum hydride, hydrazine, sodium sulfite, sodium thiosulfate and the like are used. The amount of the reducing agent to be used is 1.1 times or more, generally 1.5 to 5 times the molar amount of the theoretical amount necessary for reducing the supported copper compound.

There is no particular problem if the amount of the reducing agent exceeds 5 times the molar amount,
It is uneconomical to use more reducing agent than necessary. Also,
A reduction treatment with a reducing agent amount less than 1.1 times the molar amount of the reducing agent is not preferred because the reduction of the supported copper compound becomes insufficient and the performance of removing dissolved oxygen is reduced.

The processing temperature and the processing time are not particularly limited.
In general, the reaction is carried out at room temperature to 100 ° C. for 10 minutes to 24 hours, although it varies depending on the type, amount and processing time of the reducing agent. Optimal processing conditions can be set by conducting preliminary experiments as appropriate.

The method for contacting the water to be treated in which oxygen is dissolved and the chelate resin carrying copper may be a batch method in which the chelate resin carrying copper is put into the water to be treated and agitated contact is performed, but simplification of the treatment method, In consideration of the removal efficiency of dissolved oxygen, downsizing of the apparatus, and the like, a column flow method in which water to be treated is passed through a resin tower filled with a chelate resin carrying copper is preferable.
In the case of the column passing method, the liquid can be passed at a normal water treatment rate with an ion exchange resin, and is not particularly limited. In general, the liquid is passed at a superficial velocity of SV = ¹ to 500 Hr ⁻¹ .

Although the reaction between the copper-supported chelate resin and the dissolved oxygen used in the method of the present invention is very fast, it is preferable to carry out the reaction at SV = ^{1 to} about 50 Hr ^{-1 in} consideration of a drift problem, a liquid pressure loss and the like. If SV is smaller than 1, the amount of water to be treated per unit time is reduced, and if it is larger than 50, the efficiency of removing dissolved oxygen is reduced due to drift or the like.

In carrying out the present invention, the amount of the chelate resin supporting copper is not particularly limited, and varies depending on the contact method, the type of the chelate resin supporting copper, the dissolved oxygen concentration in the liquid to be treated, and the like. It is set by performing preliminary experiments.

The activity of the copper-supported chelate resin is higher than that of a known palladium-based ion-exchange resin. Therefore, the contact temperature between the liquid to be treated and the copper-supported chelate resin is not particularly limited, but is generally 1 ° C. or higher. Will be implemented. In particular, the temperature is desirably about 10 ° C. or higher in order to increase the reactivity between the copper-supported chelate resin and dissolved oxygen, and is preferably 80 ° C. or lower in order to suppress the quality deterioration of the copper-supported chelate resin.

The resin from which dissolved oxygen has been removed by the method of the present invention is reused as a dissolved oxygen remover by subjecting it to a reduction treatment according to the method described above.

<Effect of the Invention> According to the method of the present invention, dissolved oxygen can be easily and efficiently removed to an extremely low concentration. Also, unlike the conventionally known ion-exchange resin carrying palladium, there is no need to coexist with hydrazine, hydrogen gas, formic acid and other auxiliaries, it is safe, and there is no contamination due to mixing of auxiliaries into the processing solution, and its industrial value. Is big.

<Examples> The present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

Example 1 Inner diameter 2 filled with 10 g of a copper-supported chelate resin A shown below
0 mm glass column containing 6.9 mg / d of dissolved oxygen
C. Deionized water 10 was passed at a superficial velocity SV of 30 Hr ^-1 .
When the dissolved oxygen concentration and the copper concentration in the treated water were measured, they were 1.1 ppm and 0.01 ppm, respectively.

(Chelate resin A) 147 g of sodium monochloroacetate and 300 g of water were added to 50 g of a commercially available chelate resin Sumichelate MC-10 (manufactured by Sumitomo Chemical Co., Ltd.) having a polyalkylenepolyamino group, and the pH was further increased.
10% sodium hydroxide was added to adjust to 11-12. Thereafter, the reaction was carried out at 60 ° C. for 4 hours, followed by filtration and washing with water to obtain a chelating resin A.

(Copper supported chelate resin A) Chelate resin A (10 g) was added to 3000 mg-Cu / concentrated copper sulfate aqueous solution (100 ml), and the mixture was stirred and contacted at room temperature for 6 hours.
A copper-adsorbed chelate resin A having 299 mg of copper was obtained. 100 ml of a 10% hydrazine aqueous solution was added to the copper-adsorbed chelate resin A, and the mixture was treated at 70 to 80 ° C. for 1 hour to reduce copper to obtain a copper-supported chelate resin A.

Examples 2 to 6 The same test as in Example 1 was performed except that the copper-supported chelate resins BF shown below were used instead of the copper-supported chelate resin A.

The results are shown in Table 1.

(Chelate resin B) To 50 g of Sumichelate MC-10 (manufactured by Sumitomo Chemical Co., Ltd.), 126 g of sodium acrylate and 126 g of water were added and reacted at 40 ° C for 12 hours.

(Copper-supported chelate resin B) The chelate resin B was treated in the same manner as in Example 1, and the copper-adsorbed chelate resin B in which 300 mg of copper was adsorbed on 10 g of the chelate resin B.
I got Subsequently, a reduction treatment was performed to obtain a copper-supported chelate resin B.

(Chelate resin C) To 50 g of SUMIKAION KA-890 (manufactured by Sumitomo Chemical Co., Ltd.), which is a commercially available basic ion exchange resin having an amino group, was added 150 g of 20% formalin, 82 g of phosphorous acid, and 100 g of 36% hydrochloric acid.
After reacting at 4 ° C. for 4 hours, the mixture was filtered and washed with water to obtain chelate resin C.

(Chelate supporting chelate resin C) Chelate resin C was treated in the same manner as in Example 1, and 300 mg of copper was adsorbed on 10 g of chelate resin C.
I got Subsequently, a reduction treatment was performed to obtain a copper-supported chelate resin C.

(Copper-supported chelate resin D)
A treatment was performed under the same conditions as in Example 1 except that the amount was 200 ml, to obtain a copper-adsorbed chelate resin in which 563 mg of copper was adsorbed on 10 g of the chelate resin A. Next, a reduction treatment is carried out, and the copper-supporting chelate resin D
I got

(Copper-supported chelate resin E) A copper-adsorbed chelate resin in which 1230 mg of copper was adsorbed on 10 g of chelate resin A by treating under the same conditions as in Example 1 except that the amount of the aqueous copper sulfate solution brought into stirring contact with the chelate resin A was set to 1. I got Subsequently, a reduction treatment was performed to obtain a copper-supporting chelate resin E.

(Copper supported chelate resin F) 10 g of a commercially available chelate resin Sumikilate MC-30 produced by reacting styrene-divinylbenzene copolymer having a chloromethyl group with iminodiacetic acid in 3000 mg-Cu / concentration of copper sulfate aqueous solution 1 Was added and stirred at room temperature for 6 hours to obtain a copper-adsorbed chelate resin on which 1230 mg of copper had been adsorbed. This copper-adsorbed chelate resin was subjected to a reduction treatment to obtain a copper-supported chelate resin F.

Comparative Examples 1-3 Commercially available chelate resin Sumichelate MC-10 (manufactured by Sumitomo Chemical Co., Ltd.) having a polyalkylene polyamino group, commercially available ion exchange resin Duolite C- having a carboxylic acid group
464, using commercially available ion-exchange resin Duolite C-26 having a sulfonic acid group (Rome and Haas Co., Ltd.) to adsorb copper by the same method as in Example 1 (each adsorbs about 300 mg of copper) An exchange resin was prepared, and a copper-supported resin obtained by a reduction treatment was subjected to a dissolved oxygen removal test. The results are shown in Table 2. From the results of Examples 1 to 6 and Comparative Examples 1 to 3, the chelate resin having at least one kind of the copper-supported aminocarboxylic acid group or aminoalkylenephosphonic acid group of the present invention is excellent in the removability of dissolved oxygen and It is clear that the elution of copper ions into the treated water is small and the industrial value is large.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-53-658 (JP, A) JP-A-60-41509 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C02F 1/42 C02F 1/58 B01J 20/26 B01J 45/00

Claims (2)

(57) [Claims] 1. Removal of dissolved oxygen in water characterized by contacting a chelate resin having an aminocarboxylic acid group carrying copper and / or an aminoalkylenephosphonic acid group carrying copper with water in which oxygen is dissolved. Method. 2. The method for removing dissolved oxygen according to claim 1, wherein the carboxylic acid group and / or phosphonic acid group in the chelate resin is bonded to the polymer main chain via a polyaminoalkylene group.