Water treatment method

Abstract

To provide a water treatment method using a water treatment chemical containing a sulfonated pyrene-based compound as a fluorescent substance, in which the decomposition of the sulfonated pyrene-based compound can be suppressed even when halide ions are present in a water system at a predetermined concentration or more under an ultraviolet irradiation environment.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 halide ions are present in an amount of 60mg / L or more under ultraviolet radiation environments.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 (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 3260960 Summary of the Invention [Problem to be solved by the invention]

[0005] 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 if halide ions are present in the water system at a predetermined concentration or higher in an ultraviolet environment, such as under sunlight irradiation.

[0006] The 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 halide ions are present in the water system at a concentration greater than a predetermined level under ultraviolet irradiation. [Means for solving the problem]

[0007] The present invention is a water treatment method in which a sulfonated pyrene compound and an azole compound are present in an aqueous system containing 60 mg / L or more of halide ions under ultraviolet irradiation.

[0008] 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.

[0009] 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.

[0010] 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.

[0011] 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.

[0012] In the water treatment method, the azole compound preferably includes 1,2,3-benzotriazole.

[0013] In the water treatment method, the halide ions preferably include chloride ions. [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 halide ions are present in the water system at a concentration greater than 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 compound and an azole compound are present in an aqueous system in which halide ions are present at a concentration of 60 mg / L or more under ultraviolet irradiation.

[0017] The present inventors have confirmed that in water treatment using a water treatment agent containing a sulfonated pyrene-based compound as a fluorescent substance, the sulfonated pyrene-based compound is decomposed under ultraviolet irradiation when halide ions are present at a predetermined concentration or higher. In particular, they have confirmed that the decomposition of the sulfonated pyrene-based compound is promoted in a low concentration range of the sulfonated pyrene-based compound after addition to the aqueous system. Therefore, as a result of extensive research, the present inventors have found that by allowing an azole compound to coexist with the sulfonated pyrene-based compound, the decomposition of the sulfonated pyrene-based compound can be suppressed even when halide ions are present at a predetermined concentration or higher in the 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 halide ions include fluoride ions, chloride ions, bromide ions, and iodide ions. The water treatment method according to this embodiment can be suitably applied particularly when the aqueous system contains chloride ions.

[0021] The water treatment method according to the present embodiment can be more suitably applied when the amount of halide ions present in the aqueous system is 60 mg / L or more. There is no particular upper limit to the amount of halide ions present in the aqueous system, but it is, for example, 500 mg / L or less.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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 60 mg / L or more of halide ions are present.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] In the water treatment method according to this embodiment, in addition to the sulfonated pyrene compound and the azole compound, other components such as a slime inhibitor, a scale inhibitor, a scale cleaning agent, and a corrosion inhibitor other than the azole compound may be used in combination.

[0031] Examples of slime inhibitors include ammonium-based compounds, amine-based compounds, nitrogen-sulfur-based compounds, organometallic compounds, chlorine-based oxidizing agents such as hypochlorous acid, bromine-based oxidizing agents such as hypobromous acid, stabilized hypobromous acid compositions containing a bromine-based oxidizing agent and a sulfamic acid compound, and stabilized hypochlorous acid compositions containing a chlorine-based oxidizing agent and a sulfamic acid compound.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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 60 mg / L or more of halide ions under ultraviolet irradiation;

[0036] (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.

[0037] (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.

[0038] (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.

[0039] (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.

[0040] (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.

[0041] (7) The water treatment method according to any one of (1) to (6), The water treatment method, wherein the halide ions include chloride ions. [Example]

[0042] 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.

[0043] [Experimental Method] Water treatment agent compositions of Examples, Reference Examples and Comparative Examples were obtained by the following method.

[0044] 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.

[0045] The obtained composition was diluted 200 times with pure water, and then sodium chloride (manufactured by Kanto Chemical Co., Ltd.) was added as a halogen compound to achieve the desired 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 immersed in a UV environment (wavelength: 254 nm, intensity: 49 μW / m 2 ) and left it there.

[0046] 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).

[0047] <Reference example 1> In Reference Example 1, a water treatment agent containing no 1,2,3-benzotriazole (0 mass%) was used, and the halide ion concentrations (here, chloride ion concentrations) were set to 0, 6, 40, and 60 mg / L, and the sample was left in a UV environment for 24 hours. The results are shown in Table 1.

[0048] [Table 1]

[0049] As can be seen from Table 1, the presence of 60 mg / L of halide ions in water promoted the decomposition of PTSA.

[0050] <Example 1, Comparative Example 1> In Example 1, water treatment agents containing 0.1 mass% (mass ratio 3.75), 0.5 mass% (mass ratio 18.75), 1.0 mass% (mass ratio 37.50), and 1.5 mass% (mass ratio 56.25) of 1,2,3-benzotriazole were used, and the halide ion concentration (chloride ion concentration) was set to 60 mg / L, and the samples were left in a UV environment for 24 hours. The results of Reference Example 1, but with the halide ion concentration (chloride ion concentration) set to 60 mg / L (Reference Examples 1-4), were designated Comparative Example 1. The results are shown in Table 2.

[0051] [Table 2]

[0052] As can be seen from Table 2, the presence of the azole compound inhibited the decomposition of PTSA.

[0053] Thus, in the method of the embodiment, in water treatment using a water treatment agent containing a sulfonated pyrene-based compound as a fluorescent substance, the decomposition of the sulfonated pyrene-based compound could be suppressed even when halide ions were 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 60 mg / L or more of halide ions 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.

7. The water treatment method according to claim 1, The water treatment method, wherein the halide ions include chloride ions.

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