JP2003266082A - Dechlorination treatment agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a dechlorination treatment agent for removing free chlorine in water, improved so as to treat a large amount of water in a short time without leaving the dechlorination treatment agent itself or a component originating from the dechlorination treatment agent in water after treatment. <P>SOLUTION: This dechlorination treatment agent contains sulfur such as simple sulfur or a metal sulfide such as iron sulfide, copper sulfide or calcium sulfide as an effective component. A molded object of simple sulfur, a molded object of a metal sulfide obtained as a precipitate by adding water containing metal ions to water containing a sulfide such as hydrogen sulfide, a metal sulfide supported on an inorganic porous carrier obtained by supporting metal ions on the inorganic porous carrier and sulfatizing the metal ions with sodium sulfide or sodium hydrosulfide, or the like, are used. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a dechlorination treatment agent for removing free chlorine in water, particularly tap water.

[0002]

2. Description of the Related Art For the purpose of sterilizing tap water, a chlorine agent is added at a water purification plant and a water supply facility in front of it so that the amount of free chlorine in water discharged from the tap at the end is 0.1 mg / L or more. There is. However, the free chlorine contained in the water from the tap is a cause of chlorine odor not only when drinking as it is, but also in industrial use such as food processing. In addition, it is an impediment to pure water purification for various industrial applications where pure water is used. Therefore, a dechlorination method for removing free chlorine in water has been proposed, and many water purification devices using activated carbon, hollow fibers, etc. are commercially available for easy dechlorination for household use.

On the other hand, as a dechlorinating agent used to chemically remove chlorine, a water quality improving agent comprising L-ascorbic acid and ferric citrate (JP-A-8-66690) and ascorbic acid are treated. Slowly soluble residual chlorine removing agent solidified with quicklime etc. as an agent (Japanese Patent Application Laid-Open No. 11-1793).
No. 75) and the like, and as a method for dechlorinating using various dechlorinating agents, a method using sulfite, thiosulfate, ascorbic acid, etc. (JP-A-9-38).
No. 686), ascorbic acid, catechins, plant polyphenols and the like (JP-A-8-2433).
87), a method using a calcium sulfite granule (JP-A-7-227600), a method in which sodium sulfite is granulated with a binder such as methyl cellulose (JP-A-10-483), and copper / zinc. Method using alloy (US Pat. No. 4,642,192), 90
There is a proposal such as a method of bringing the titanium into contact with metal at a temperature of not less than 0 ° C (Japanese Patent Laid-Open No. 6-142659).

[0004]

However, the water purifying apparatus to which the conventional dechlorinating agent or dechlorinating method as described above is applied is simple to use, but the apparatus is relatively large, and the water purifying treatment is further performed. It has the drawback of requiring a long time, a small processing capacity, and a high cost. On the other hand, the chemical dechlorination method has other problems such as the treatment agent remaining in the treated water.

The object of the present invention is to improve so that a dechlorinating agent itself or a component derived from the dechlorinating agent does not remain in the treated water and a large amount of water can be treated in a short time. Another object of the present invention is to provide a dechlorination treatment agent for removing free chlorine in water.

[0006]

In order to solve the above-mentioned problems, the invention according to claim 1 is a dechlorinating agent, which contains sulfur and metal sulfide [where metal is a group 2 to 12 of the periodic table]. Representing a metal element of [1]] is contained as an active ingredient.

The invention according to claim 2 is the dechlorinating agent according to claim 1, wherein the active ingredient is elemental sulfur.

The invention according to claim 3 is the dechlorinating agent according to claim 1, wherein the active ingredient is a metal ion in water containing a sulfide [where the metal is a group 2 to 12 of the periodic table]. Which represents a metal element of [1], and is a precipitate obtained by adding water. The invention according to claim 4 is the dechlorinating agent according to claim 1, wherein the active ingredient is selected from the group consisting of iron sulfide, copper sulfide, and calcium sulfide.
It is characterized by being more than one species.

The invention according to claim 5 is the dechlorinating agent according to claim 1, wherein the active ingredient is a metal sulfide [where the metal represents a metal element of Groups 2 to 12 of the periodic table]. ] One or more types of the above] are supported on an inorganic porous carrier.

The invention according to claim 6 is the dechlorinating agent according to claim 5, wherein the metal sulfide is loaded on the inorganic porous carrier by loading a metal ion on the zeolite [where the metal is the periodic table]. It represents a metal element of Group 2 to Group 12] by carrying it by exchange, and then sulfided with sodium sulfide or sodium hydrosulfide.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The dechlorinating agent of the present invention removes free chlorine by reacting with free chlorine in water. Here, free chlorine is hypochlorous acid (HOCl) formed when a chlorine agent is dissolved in water, or hypochlorite ion (OCl ⁻ ) generated by dissociation of hypochlorous acid in water.

In the dechlorinating agent of the present invention, the active ingredient is selected from the group consisting of sulfur and metal sulfides.
The sulfur is solid elemental sulfur such as orthorhombic sulfur, mono-orthorhombic sulfur, and amorphous (rubber) -like sulfur, and may be sulfur hot spring flower obtained at a hot spring.

Metal sulfides are 2 of the periodic table of the 18th group elements.
It is a sulfide of a metal element belonging to Groups 12 to 12. Among these, metal sulfides that are not toxic and are inexpensive can be obtained in consideration of their use in water treatment. For this reason, iron sulfide, copper sulfide, calcium sulfide,
Titanium sulfide, vanadium sulfide, manganese sulfide, cobalt sulfide, nickel sulfide, zinc sulfide and barium sulfide are preferable, and iron sulfide, copper sulfide and calcium sulfide are particularly preferable. Some metal sulfides form sulfides or polysulfides that differ depending on the oxidation state of the metal. For example, for iron, iron (II) sulfide [FeS], iron (III) sulfide [Fe ₂ S ₃ ], Iron disulfide [FeS ₂ ] 3
Species are known, but any sulfide is included in the present invention.

The metal sulfide may be obtained by crushing naturally occurring sulfide ore, but water containing metal ions is added to water containing sulfides such as hydrogen sulfide and sodium sulfide to cause precipitation. It may be obtained from

The active ingredient for dechlorination in the present invention is selected from the group consisting of sulfur and metal sulfides as described above, but one of them may be used alone or two of them may be used. The above may be used in any combination.

The dechlorination treatment agent is carried out only by contacting with water containing free chlorine to be treated. Therefore, the purpose can be achieved by simply adding the dechlorinating agent into the water.
In practical use, it is convenient to mix sulfur and / or metal sulfides singly or in any combination of two or more to form particles or pellets having an appropriate size. Upon molding, pressure molding may be performed using an inorganic compound such as calcium carbonate or an organic compound such as methyl cellulose as a binder. Alternatively, it may be supported on an inorganic porous carrier such as granular zeolite. The method of supporting on an inorganic porous carrier is, for example, preparing a water-soluble aqueous solution of a metal salt, impregnating the inorganic porous carrier therein to ion-exchange on the carrier to fix the metal, and then sodium sulfide or It can be carried out by bringing the solution into contact with an aqueous solution of sodium hydrosulfide and sulfiding it.

A molded product of sulfur and / or metal sulfide or a supported product on an inorganic porous carrier is packed in a column and the water to be treated is allowed to pass therethrough, whereby free chlorine in water is easily and efficiently obtained. Will be removed.

[0018]

Example 1 A commercially available sulfur hot spring flower was spherically pressure-molded and classified into 0.8 to 1.2 mmφ with a sieve and used as a dechlorinating agent.

(Example 2) Iron (II) sulfide (FeS) /
Zeolite was used as a dechlorination agent. Particle size 1mmφ
After washing 20 g of X-type zeolite with ion-exchanged water, 2
0 wt% iron (II) sulfate (FeSO ₄ ) aqueous solution 100 m
It was immersed in L and left to stand for about 20 hours for ion exchange. This zeolite was taken out of the solution, washed with ion-exchanged water, immersed in 100 mL of an 8% aqueous solution of sodium hydrosulfide, and allowed to stand for about 20 hours to make iron on the zeolite iron sulfide. The aqueous sodium hydrosulfide solution was separated and washed with deionized water. Iron retention on zeolite (as metal) is 1
It was 1 mg / g (zeolite).

(Example 3) Copper (II) sulfide (CuS) /
Zeolite was used as a dechlorination agent. Iron sulfate (I
I) Example 2 using the FeS / zeolite, except that copper (II) sulfate (CuSO ₄ ) was used instead of the aqueous solution.
Was prepared in the same manner as. Copper retention on zeolite (as metal) (as metal) is 13 mg / g (zeolite)
Met.

Example 4 Calcium sulfide (CaS) /
Zeolite was used as a dechlorination agent. Iron sulfate (I
I) Example 2 using the FeS / zeolite except that calcium chloride (CaCl ₂ ) was used instead of the aqueous solution
Was prepared in the same manner as. The calcium retention on the zeolite (as metal) was 8 mg / g (zeolite).

Comparative Example 1 A 1: 1 (weight ratio) alloy of copper and nickel having an average particle size of about 1 mmφ was used as a dechlorination agent. (Comparative Example 2) Coal-based activated carbon having an average particle size of about 1 mmφ was used as a dechlorination agent.

Comparative Example 3 20 g of X-type zeolite having a particle diameter of 1 mmφ was washed with ion-exchanged water, immersed in 100 mL of 20% cobalt sulfate (CoSO ₄ ) aqueous solution, and allowed to stand for about 20 hours for ion exchange. . This zeolite was taken out of the solution and washed with ion-exchanged water, and then sodium hydroxide 13% by weight and sodium hypochlorite 5% by weight (Cl
_It was immersed in 15 mL of a mixed solution containing (as No. ₂ ) and contacted for 20 hours. The zeolite thus treated was separated from the mixed solution, washed with water and used as a dechlorination treatment agent. The amount of metal retained on the zeolite was 14 mg / g (zeolite).

(Comparative Example 4) Calcium sulfite (C
aSO ₃ ) and press-molding it into particles,
1.2 mmφ was classified and used as a dechlorination agent. Comparative Example 5 Untreated zeolite was used as a dechlorination agent.

Test method: With respect to the dechlorinating agents of Examples 1 to 4 and Comparative Examples 1 to 5 described above, dechlorination effects were evaluated according to the following methods.

A deionization treatment agent was packed in an apparent volume of 2 mL in a 25 mmφ glass column, and test water having a free chlorine concentration of 0.68 mg / L was supplied from the bottom of the column at a space velocity of 300 m.
Flowed at L / hour. 1000 against the filling amount of dechlorination agent
About the amount of free chlorine after passing double amount (volume) of water,
Sulfate ion and metal content were measured. The amount of free chlorine was measured by the diethyl-p-phenylenediamine (DPD) method, the sulfate ion was sufficiently contacted with air in the test water, and then ion chromatography was performed. MS) method.

Test results: The results obtained are shown in Table 1.

[Table 1] From these results, it was confirmed that the sulfur and metal sulfides of the present invention are effective in removing free chlorine in water.

[0028]

The dechlorinating agent of the present invention exhibits a desired dechlorinating action only by bringing it into contact with the water to be treated, and therefore, the method of use is simple, and the dechlorinating agent is excellent even when a large amount of water is run. Demonstrates its ability, and even in a small device, an effective dechlorination effect can be obtained in a short time. Further, the amount of metal ions eluted in the treated water is small, and good water quality can be obtained.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B01J 20/18 B01J 20/18 EF term (reference) 4D038 AA04 AB39 BB06 BB08 4G066 AA07B AA46B AA62B CA31 DA07

Claims (6)

[Claims] 1. An active ingredient comprising at least one selected from the group consisting of sulfur and a metal sulfide (where the metal represents a metal element of Groups 2 to 12 of the Periodic Table). Dechlorination treatment agent. 2. The dechlorinating agent according to claim 1, wherein the active ingredient is elemental sulfur. 3. A precipitate obtained by adding water containing a metal ion [where metal represents a metal element of Group 2 to Group 12 of the Periodic Table] to water containing a sulfide. The dechlorination treatment agent according to claim 1, wherein the dechlorination treatment agent is present. 4. The dechlorinating agent according to claim 1, wherein the active ingredient is at least one selected from the group consisting of iron sulfide, copper sulfide, and calcium sulfide. 5. The inorganic porous carrier, wherein the active ingredient is one or more kinds of metal sulfide (wherein metal represents a metal element of Groups 2 to 12 of the Periodic Table). The dechlorination treatment agent according to claim 1, wherein 6. The supporting of metal sulfide on the inorganic porous carrier is carried out by carrying out exchange of metal ions on a zeolite [where metal represents a metal element of Group 2 to Group 12 of the Periodic Table], followed by sulfidation. The dechlorinating agent according to claim 5, which is obtained by sulfiding with sodium or sodium hydrosulfide.