Water treatment method

Abstract

To provide a water treatment method capable of suppressing the decomposition of a sulfonated pyrene-based compound even if an oxidizing agent is present in a water system at a predetermined concentration or more under an ultraviolet irradiation environment in water treatment using a water treatment chemical containing the sulfonated pyrene-based compound as a fluorescent substance.SOLUTION: In the water treatment method, a sulfonated pyrene-based compound and an azole compound are allowed to be present in a water system in which an oxidizing agent is present in an amount of ≥ 0. 1mg - Cl / L under UV irradiation.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a water treatment method using a water treatment chemical. [Background technology]

[0002] Water treatment agents used in water systems such as cooling water systems contain various slime inhibitors, scale inhibitors, corrosion inhibitors, etc. to inhibit biofouling, scale, corrosion, etc. In order to obtain the optimal effect of such water treatment agents, it is desirable to measure the concentration of the water treatment agent in the water system and control the amount added. One known method for doing so is to add a reference substance, a so-called tracer substance, to measure changes in the water treatment agent over time.

[0003] Fluorescent substances such as sulfonated pyrene compounds are known as tracer substances, and the concentration of water treatment agents in water systems is controlled by a fluorescent tracer method using a fluorescent sensor.

[0004] For example, Patent Document 1 describes a water treatment composition that combines a chlorine-based oxidizing agent or a bromine-based oxidizing agent, a sulfamic acid compound, and a fluorescent substance such as a sulfonated pyrene-based compound into a single agent. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6655295 Summary of the Invention [Problem to be solved by the invention]

[0006] The present inventors have newly discovered that when a water system is treated using the water treatment agent disclosed in Patent Document 1, the decomposition of sulfonated pyrene-based compounds may be accelerated in an ultraviolet environment, such as under sunlight, if an oxidizing agent is present in the water system at a concentration equal to or greater than a predetermined level.

[0007] An object of the present invention is to provide a water treatment method that uses a water treatment agent containing a sulfonated pyrene-based compound as a fluorescent substance, and that can suppress the decomposition of the sulfonated pyrene-based compound even when an oxidizing agent is present in the water system at a concentration greater than a predetermined level under ultraviolet irradiation. [Means for solving the problem]

[0008] The present invention is a water treatment method in which a sulfonated pyrene compound and an azole compound are present in an aqueous system in which an oxidizing agent is present at 0.1 mg-Cl / L or more under ultraviolet irradiation.

[0009] In the water treatment method, the sulfonated pyrene-based compound is preferably at least one selected from the group consisting of pyrene tetrasulfonic acid and pyrene tetrasulfonate salts.

[0010] In the water treatment method, the ratio of the azole compound to the sulfonated pyrene compound in the water system is preferably in the range of 1 to 100 as a mass ratio.

[0011] In the water system of the water treatment method, the azole compound is preferably present in a range of 0.05 to 3.0 mg / L, and the sulfonated pyrene compound is preferably present in a range of 1 to 100 μg / L.

[0012] In the water treatment method, it is preferable that the ratio of the azole compound to the sulfonated pyrene compound in the aqueous system is in the range of 1 to 100 as a mass ratio, and that the azole compound is present in the range of 0.05 to 3.0 mg / L and the sulfonated pyrene compound is present in the range of 1 to 100 μg / L in the aqueous system.

[0013] In the water treatment method, the azole compound preferably includes 1,2,3-benzotriazole. [Effects of the Invention]

[0014] The present invention provides a water treatment method that uses a water treatment agent containing a sulfonated pyrene compound as a fluorescent substance, and that can suppress the decomposition of the sulfonated pyrene compound even when an oxidizing agent is present in the water system at a concentration above a predetermined level under ultraviolet irradiation. DETAILED DESCRIPTION OF THE INVENTION

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes an embodiment of the present invention. The embodiment is an example of implementing the present invention, and the present invention is not limited to the embodiment.

[0016] The water treatment method according to this embodiment is a method in which a sulfonated pyrene-based compound and an azole compound are present in an aqueous system in which an oxidizing agent is present at 0.1 mg-Cl / L or more under ultraviolet irradiation.

[0017] The present inventors have confirmed that in water treatment using a water treatment chemical containing a sulfonated pyrene compound as a fluorescent substance, the sulfonated pyrene compound is decomposed when an oxidizing agent is present at a predetermined concentration or higher under ultraviolet irradiation. While the stability of the sulfonated pyrene compound was not a problem in the water treatment chemical, they confirmed that the decomposition of the sulfonated pyrene compound is promoted at low concentrations after addition to an aqueous system. Consequently, as a result of extensive research by the present inventors, they have found that by allowing an azole compound to coexist with the sulfonated pyrene compound, the decomposition of the sulfonated pyrene compound can be suppressed even when an oxidizing agent is present at a predetermined concentration or higher in an aqueous system under ultraviolet irradiation.

[0018] Examples of sulfonated pyrene compounds include pyrene tetrasulfonic acid and pyrene tetrasulfonate salts, and it is preferable to use 1,3,6,8-pyrene tetrasulfonate tetrasodium salt (PTSA) in terms of stability, etc. One type of sulfonated pyrene compound may be used, or two or more types may be used in combination.

[0019] Examples of the azole compounds include those that function as metal corrosion inhibitors (corrosion inhibitors) for copper-based metals such as copper and copper alloys, and examples thereof include 1,2,4-triazole, 1-methyl-1,2,4-triazole, 3-methyl-1,2,4-triazole, 3,5-dimethyl-1,2,4-triazole, 3,5-diethyl-1,2,4-triazole, 1-phenyl-1,2,4-triazole, 3-phenyl-1,2,4-triazole, 1,5-diphenyl-1,2,4-triazole, and 1,3-diphenyl-1,2,4-triazo urazole, 3,5-diphenyl-1,2,4-triazole, 1,2,4-triazol-3-one, 5-methyl-1,2,4-triazol-3-one, 3-methyl-1,2,4-triazol-5-one, 1-phenyl-1,2,4-triazol-3-one, 5-phenyl-1,2,4-triazol-3-one, 1-phenyl-1,2,4-triazol-5-one, urazole, 1-phenylurazole, 4-phenylurazole, 1,2,3-benzotriazole, 1-methylbenzotriazole, 4-methylbenzotriazole, 5-Methylbenzotriazole, 5,6-methylbenzotriazole, 2-phenylbenzotriazole, 1-oxybenzotriazole, 2-(3-t-butyl-5-methyl-2-hydroxyphenyl)-5-chlorobenzotriazole, 2-(5-methyl-2-hydroxyphenyl)benzotriazole, 2-(3,5-di-t-amyl-2-hydroxyphenyl)benzotriazole, 2-(3,5-di-t-butyl-2-hydroxyphenyl)-5-chlorobenzotriazole, 2-(3,5-di-t-butyl-2-hydroxyphenyl)- nyl)benzotriazole, 2-(2'-hydroxy-5-octylphenyl)benzotriazole, 2-(2-hydroxy-4'-octoxyphenyl)benzotriazole, 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-(2'-hydroxy-5'-t-butylphenyl)benzotriazole, 2-(2'-hydroxy-3-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2-hydroxy-3,5-t-aminophenyl)benzotriazole, 2-(2'-hydroxy-3',Examples of suitable azole compounds include 5'-di-t-butyl)-5-chlorobenzotriazole, 2-(2-hydroxy-3,5-di-t-butylphenyl)benzotriazole, 2-[2-hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl]-2H-benzotriazole, 1-naphthylbenzotriazole, 5-chlorobenzotriazole, 5-bromobenzotriazole, 5-nitrobenzotriazole, and 4,5,6,7-tetrahydrobenzotriazole. Among these, 1,2,3-benzotriazole, 4-methylbenzotriazole, and 5-methylbenzotriazole are preferred, with 1,2,3-benzotriazole being more preferred, in terms of distribution volume and cost. One type of azole compound may be used, or two or more types may be used in combination.

[0020] Examples of the oxidizing agent include a chlorine-based oxidizing agent, a bromine-based oxidizing agent, a stabilized hypochlorous acid composition containing a chlorine-based oxidizing agent and a sulfamic acid compound, and a stabilized hypobromous acid composition containing a bromine-based oxidizing agent and a sulfamic acid compound. The water treatment method according to this embodiment can be suitably applied particularly when the aqueous system contains a chlorine-based oxidizing agent or a bromine-based oxidizing agent and a sulfamic acid compound.

[0021] Examples of chlorine-based oxidizing agents include chlorine gas, chlorine dioxide, hypochlorous acid or its salts, chlorous acid or its salts, chloric acid or its salts, perchloric acid or its salts, and chlorinated isocyanuric acid or its salts. Among these, examples of salts include alkali metal hypochlorites such as sodium hypochlorite and potassium hypochlorite, alkaline earth metal hypochlorites such as calcium hypochlorite and barium hypochlorite, alkali metal chlorites such as sodium chlorite and potassium chlorite, alkaline earth metal chlorites such as barium chlorite, other metal chlorites such as nickel chlorite, alkali metal chlorates such as ammonium chlorate, sodium chlorate, and potassium chlorate, and alkaline earth metal chlorates such as calcium chlorate and barium chlorate. These chlorine-based oxidizing agents may be used alone or in combination of two or more. As the chlorine-based oxidizing agent, sodium hypochlorite is preferred from the viewpoint of ease of handling.

[0022] Examples of bromine-based oxidizing agents include bromine (liquid bromine), bromine chloride, bromic acid, bromates, hypobromous acid, etc. Hypobromous acid may be produced by reacting a bromine compound such as sodium bromide with a chlorine-based oxidizing agent such as hypochlorous acid.

[0023] The "stabilized hypochlorous acid composition containing a chlorine-based oxidizing agent and a sulfamic acid compound" may be a stabilized hypochlorous acid composition containing a mixture of a "chlorine-based oxidizing agent" and a "sulfamic acid compound," or may be a stabilized hypochlorous acid composition containing a "reaction product of a chlorine-based oxidizing agent and a sulfamic acid compound." The "stabilized hypobromous acid composition containing a bromine-based oxidizing agent and a sulfamic acid compound" may be a stabilized hypobromous acid composition containing a mixture of a "bromine-based oxidizing agent" and a "sulfamic acid compound," or may be a stabilized hypobromous acid composition containing a "reaction product of a bromine-based oxidizing agent and a sulfamic acid compound."

[0024] Examples of bromine compounds include sodium bromide, potassium bromide, lithium bromide, ammonium bromide, and hydrobromic acid. Of these, sodium bromide is preferred from the viewpoint of formulation costs.

[0025] The sulfamic acid compound is, for example, a compound represented by the following general formula (1). R2NSO3H (1) (In the formula, R is independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.)

[0026] Examples of sulfamic acid compounds include sulfamic acid (amidosulfuric acid) in which both R groups are hydrogen atoms, as well as sulfamic acid compounds in which one of the R groups is a hydrogen atom and the other is an alkyl group having 1 to 8 carbon atoms, such as N-methylsulfamic acid, N-ethylsulfamic acid, N-propylsulfamic acid, N-isopropylsulfamic acid, and N-butylsulfamic acid; sulfamic acid compounds in which both of the R groups are alkyl groups having 1 to 8 carbon atoms, such as N,N-dimethylsulfamic acid, N,N-diethylsulfamic acid, N,N-dipropylsulfamic acid, N,N-dibutylsulfamic acid, N-methyl-N-ethylsulfamic acid, and N-methyl-N-propylsulfamic acid; sulfamic acid compounds in which one of the R groups is a hydrogen atom and the other is an aryl group having 6 to 10 carbon atoms, such as N-phenylsulfamic acid; and salts thereof. Examples of sulfamic acid salts include alkali metal salts such as sodium salts and potassium salts, alkaline earth metal salts such as calcium salts, strontium salts and barium salts, other metal salts such as manganese salts, copper salts, zinc salts, iron salts, cobalt salts and nickel salts, ammonium salts and guanidine salts.Sulfamic acid compounds and their salts may be used alone or in combination of two or more.As the sulfamic acid compound, sulfamic acid (amidosulfuric acid) is preferably used from the viewpoint of environmental load.

[0027] The amount of oxidizing agent present in the aqueous system is 0.01 mg-Cl / L or more, and the water treatment method according to this embodiment can be more suitably applied when the amount is 0.1 mg-Cl / L or more. There is no particular upper limit to the amount of oxidizing agent present in the aqueous system, but it is, for example, 50 mg-Cl / L or less. Note that the concentration of the oxidizing agent is measured in terms of "total chlorine equivalent concentration" (mg-Cl / L), which is a value measured by a total chlorine measurement method, in order to compare the concentration of the "chlorine-based oxidizing agent" using the same units.

[0028] In this specification, "under ultraviolet irradiation environment" refers to an environment where light containing ultraviolet rays (for example, light having a wavelength of 100 to 400 nm) is irradiated (for example, light having an intensity of 0.01 mW / m 2 ~4×10 5 mW / m 2 ) and there are no particular limitations. The ultraviolet irradiation environment includes exposure to sunlight.

[0029] In the water treatment method according to this embodiment, by having the azole compound present in a predetermined ratio or more relative to the sulfonated pyrene compound, the decomposition of the sulfonated pyrene compound is further suppressed. The mass ratio of the azole compound to the sulfonated pyrene compound in the aqueous system is preferably in the range of 1 to 100, more preferably 3.75 to 100, and even more preferably 3.75 to 56.25. If the mass ratio of the azole compound to the sulfonated pyrene compound in the aqueous system is less than 1, it may be difficult to achieve the effect of suppressing the decomposition of the sulfonated pyrene compound, and if it exceeds 100, production costs may increase.

[0030] In the water system in the water treatment method according to this embodiment, the azole compound is present in an amount of preferably 0.05 to 3.0 mg / L, more preferably 0.05 to 2.0 mg / L, and even more preferably 0.075 to 1.125 mg / L. If the amount of the azole compound present in the water system is less than 0.05 mg / L, it may be difficult to achieve the effect of inhibiting the decomposition of sulfonated pyrene-based compounds, and if it exceeds 3.0 mg / L, production costs may increase.

[0031] In the water system in the water treatment method according to this embodiment, the sulfonated pyrene-based compound is preferably present in a range of 1 to 100 μg / L, and more preferably in a range of 10 to 100 μg / L. If the amount of the sulfonated pyrene-based compound present in the water system is less than 1 μg / L, it may be difficult to detect the concentration, and if it exceeds 100 μg / L, decomposition of the sulfonated pyrene-based compound is unlikely to occur even if 0.1 mg-Cl / L or more of an oxidizing agent is present.

[0032] In the water system in the water treatment method according to this embodiment, it is preferable that the ratio of the azole compound to the sulfonated pyrene compound in the water system is in the range of 1 to 100 as a mass ratio, and that the azole compound is present in the range of 0.05 to 3.0 mg / L and the sulfonated pyrene compound is present in the range of 1 to 100 μg / L in the water system.

[0033] The water treatment method according to the present embodiment can be applied to the treatment of industrial water systems such as cooling water, papermaking process water in the paper and pulp industry, etc. The water treatment method according to the present embodiment can be suitably applied to the treatment of industrial water systems such as cooling water.

[0034] The pH of the aqueous system is, for example, in the range of 5.0 to 9.0, preferably in the range of 5.0 to 8.5, and more preferably in the range of 6.5 to 8.5. If the pH of the aqueous system is less than 5.0, corrosive gases may be generated, and if it exceeds 9.0, scale may be generated.

[0035] The pH of the aqueous system may be adjusted using, for example, a pH adjuster such as an acid (e.g., hydrochloric acid, sulfuric acid, or nitric acid) or an alkali (e.g., an aqueous sodium hydroxide solution or an aqueous potassium hydroxide solution), although the pH adjustment is not particularly limited as long as the pH can be adjusted to fall within the above-mentioned range.

[0036] In the water treatment method according to this embodiment, in addition to the sulfonated pyrene compound, the azole compound, and the oxidizing agent, other components such as a slime inhibitor other than the oxidizing agent, a scale inhibitor, a scale cleaning agent, and a corrosion inhibitor other than the azole compound may be used in combination.

[0037] Examples of slime inhibitors other than the above-mentioned oxidizing agents include ammonium compounds, amine compounds, nitrogen-sulfur compounds, and organometallic compounds.

[0038] Examples of scale inhibitors include acrylic acid polymers, maleic acid polymers, methacrylic acid polymers, sulfonic acid polymers, phosphoric acid polymers, itaconic acid polymers, isobutylene polymers, and water-soluble salts thereof.

[0039] Examples of scale cleaning agents include amine polymers such as ethylenediamine and diethylenetriamine, aminocarboxylic acid polymers such as nitrilotriacetic acid, ethylenediaminetetraacetate and diethylenetriaminepentaacetic acid, and organic carboxylic acids such as gluconic acid, citric acid, oxalic acid, formic acid, tartaric acid, phytic acid, succinic acid and lactic acid.

[0040] Examples of corrosion inhibitors for iron include phosphates, phosphonic acid, zinc, molybdic acid, and nitrous acid. Examples of corrosion inhibitors for copper-based metals such as copper and copper alloys include the above-mentioned azole compounds.

[0041] The present specification includes the following embodiments. (1) A water treatment method comprising the steps of: providing a sulfonated pyrene compound and an azole compound in an aqueous system containing an oxidizing agent at 0.1 mg-Cl / L or more under ultraviolet irradiation;

[0042] (2) The water treatment method according to (1), The water treatment method, wherein the sulfonated pyrene-based compound is at least one selected from the group consisting of pyrene tetrasulfonic acid and pyrene tetrasulfonate salts.

[0043] (3) The water treatment method according to (1) or (2), The water treatment method, wherein the ratio of the azole compound to the sulfonated pyrene compound in the water system is in the range of 1 to 100 as a mass ratio.

[0044] (4) The water treatment method according to any one of (1) to (3), The water treatment method, wherein the azole compound is present in the range of 0.05 to 3.0 mg / L and the sulfonated pyrene compound is present in the range of 1 to 100 μg / L in the water system.

[0045] (5) The water treatment method according to any one of (1) to (4), The water treatment method, wherein the ratio of the azole compound to the sulfonated pyrene compound in the aqueous system is in the range of 1 to 100 as a mass ratio, and the azole compound is present in the aqueous system in a range of 0.05 to 3.0 mg / L and the sulfonated pyrene compound is present in a range of 1 to 100 μg / L.

[0046] (6) The water treatment method according to any one of (1) to (5), The water treatment method, wherein the azole compound comprises 1,2,3-benzotriazole. [Example]

[0047] EXAMPLES The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0048] [Experimental Method] Water treatment agent compositions of Examples and Comparative Examples were obtained by the following method.

[0049] Tetrasodium 1,3,6,8-pyrenetetrasulfonate (PTSA (Spectra Colors)) was mixed at 0.03 mass% with 1,2,3-benzotriazole at five concentrations: 0 mass%, 0.1 mass% (mass ratio of azole compound to sulfonated pyrene compound: 3.75), 0.5 mass% (mass ratio: 18.75), 1.0 mass% (mass ratio: 37.50), and 1.5 mass% (mass ratio: 56.25). The remainder was dissolved in pure water to make the total mass 100, and a water treatment agent was obtained.

[0050] The obtained composition was diluted 200 times with pure water, and then an oxidizing agent was added to the composition so as to obtain the predetermined active ingredient concentration shown in Table 1, and the composition was further diluted 66 times with pure water. The obtained solution was stored in a sealed polystyrene container and then subjected to UV irradiation at 25°C under a UV environment (wavelength: 254 nm, intensity: 49 μW / m 2 ) and left it there.

[0051] The fluorescence intensity at the start of exposure to UV light and after 24 hours was measured at a fluorescence wavelength of 377 nm using a spectrofluorometer RF-5300 (Shimadzu Corporation), and the PTSA residual rate was calculated as (fluorescence intensity after 24 hours) / (initial fluorescence intensity).

[0052] <Example 1, Comparative Example 1> In Example 1 and Comparative Example 1, a 12% aqueous solution of sodium hypochlorite was added as an oxidizing agent so as to have a concentration of 0.1 mg-Cl / L. The results are shown in Table 1.

[0053] <Example 2, Comparative Example 2> In Example 2 and Comparative Example 2, a hypobromous acid stabilized composition prepared by mixing 16.9% by weight (wt%) liquid bromine, 10.7% by weight sulfamic acid, 12.9% by weight sodium hydroxide, 3.94% by weight potassium hydroxide, and the remainder water was added as an oxidizing agent to a concentration of 0.1 mg-Cl / L under a nitrogen atmosphere. The pH of the prepared hypobromous acid stabilized composition was 14, and the total chlorine concentration was 7.5% by weight. The results are shown in Table 2.

[0054] The total chlorine concentration is a value (mg-Cl / L) measured by the total chlorine measurement method (DPD (diethyl-p-phenylenediamine) method) using a HACH multi-parameter water quality analyzer DR / 4000. The concentration of the "stabilized hypobromous acid composition" can also be expressed as bromine concentration (mg-Br / L), but in this case, to compare it with the concentration of the "chlorine-based oxidizing agent" using the same units, we will use the "total chlorine equivalent concentration" (mg-Cl / L), which is a value measured by the total chlorine measurement method.

[0055] <Example 3, Comparative Example 3> In Example 3 and Comparative Example 3, a hypochlorous acid stabilized composition prepared by mixing 50% by mass of 12% sodium hypochlorite aqueous solution, 1610% by mass of sulfamic acid, 8% by mass of sodium hydroxide, and the remainder of water was added as an oxidizing agent to a concentration of 0.1 mg-Cl / L. The pH of the prepared hypochlorous acid stabilized composition was 14, and the total chlorine concentration was 6% by mass. The results are shown in Table 3.

[0056] [Table 1]

[0057] [Table 2]

[0058] [Table 3]

[0059] As can be seen from Tables 1 to 3, the presence of an azole compound inhibited the decomposition of PTSA.

[0060] Thus, in the method of the embodiment, in water treatment using a water treatment agent containing a sulfonated pyrene compound as a fluorescent substance, the decomposition of the sulfonated pyrene compound was suppressed even when an oxidizing agent was present in the water system at a concentration above a predetermined level under ultraviolet irradiation.

Claims

1. A water treatment method comprising the steps of: providing a sulfonated pyrene compound and an azole compound in an aqueous system containing an oxidizing agent at a concentration of 0.1 mg-Cl / L or more under ultraviolet irradiation;

2. The water treatment method according to claim 1, The water treatment method, wherein the sulfonated pyrene-based compound is at least one selected from the group consisting of pyrene tetrasulfonic acid and pyrene tetrasulfonate.

3. The water treatment method according to claim 1, A water treatment method characterized in that the ratio of the azole compound to the sulfonated pyrene compound in the water system is in the range of 1 to 100 in terms of mass ratio.

4. The water treatment method according to claim 1, a water treatment method characterized in that the azole compound is present in the range of 0.05 to 3.0 mg / L and the sulfonated pyrene compound is present in the range of 1 to 100 μg / L in the water system;

5. The water treatment method according to claim 1, a mass ratio of the azole compound to the sulfonated pyrene compound in the aqueous system of 1 to 100, and the azole compound is present in the aqueous system at a concentration of 0.05 to 3.0 mg / L and the sulfonated pyrene compound is present in the aqueous system at a concentration of 1 to 100 μg / L.

6. The water treatment method according to claim 1, The water treatment method, wherein the azole compound includes 1,2,3-benzotriazole.

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