TW201627057A - Slime control method for separation membrane - Google Patents

Abstract

This invention provides a slime control method in a separation membrane that is capable of reducing the content of trihalomethane in permeating water while having sufficient effects on slime control in a membrane separation device which uses supply water or washing water containing trihalomethane precusor. Disclosed is a slime control method for a separation membrane with the existence of a bromine-based oxidizer, or a product between a bromine compound and a chlorine-based oxidizer; or a bromine-based oxidizer, or a product between a bromine compound and a chlorine-based oxidizer, and a sulfamic acid compound; or reaction products between a bromine-based oxidizer, or a product between a bromine compound and a chlorine-based oxidizer, and a sulfamic acid compound, in the supply water or washing water which contains the trihalomethane precursor and is supplied to the membrane separation device equipped with a separation membrane.

Description

Separation film adhesion inhibition method

The present invention relates to a method for suppressing the viscosity of a separation membrane such as a reverse osmosis membrane (RO membrane).

As a method of suppressing the viscosity of a separation membrane such as a reverse osmosis membrane (RO membrane), a method using various viscosity inhibitors is known. A chlorine-based oxidizing agent such as hypochlorous acid is a typical viscosity inhibitor, and is usually added to the front stage of the separation membrane for the purpose of suppressing the viscosity in the system. Since the chlorine-based oxidizing agent is highly likely to deteriorate the separation membrane, it is generally used to reduce or decompose the chlorine-based oxidizing agent immediately before contacting the separation membrane, or to intermittently flow the chlorine-based oxidizing agent into the separation membrane (see Patent Document 1). [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 9-057076

[The subject to be solved by the invention]

It is known that when a trihalomethane precursor such as humus is present in water, the chlorine-based oxidant reacts with it to form a trihalomethane such as chloroform. Here, it has been found out by the inventors of the present invention that the trihalomethane produced by the chlorine-based oxidizing agent is difficult to be removed by the separation membrane, and there is a problem that it is likely to leak into the permeated water of the separation membrane.

An object of the present invention is to provide a method for inhibiting the viscosity of a separation membrane which has a sufficient viscosity inhibition effect and a reduced permeability in a membrane separation apparatus using a water supply or wash water containing a trihalomethane precursor. Trihalomethane content. [Means to solve the problem]

The present invention relates to a method for inhibiting the viscosity of a separation membrane, wherein a bromine-based oxidizing agent or a reaction product of a bromine compound and a chlorine-based oxidizing agent is provided in a water supply or washing water containing a membrane separation device having a separation membrane supplied with a trihalomethane precursor material. "presence.

The present invention relates to a method for inhibiting the viscosity of a separation membrane, wherein a bromine-based oxidizing agent or a reaction product of a bromine compound and a chlorine-based oxidizing agent is provided in a water supply or washing water containing a membrane separation device having a separation membrane supplied with a trihalomethane precursor material. , with an amine sulfonic acid compound.

The present invention relates to a method for inhibiting the viscosity of a separation membrane, wherein a bromine-based oxidizing agent or a reaction product of a bromine compound and a chlorine-based oxidizing agent is provided in a water supply or washing water containing a membrane separation device having a separation membrane supplied with a trihalomethane precursor material. The product which reacts with the amine sulfonic acid compound is present.

The present invention relates to a method for inhibiting the adhesion of a separation membrane, which comprises a mixture of bromine and an aminesulfonic acid compound, or a bromine and an amine sulfonate in a water supply or washing water containing a membrane separation device having a separation membrane supplied with a trihalomethane precursor material. The product of the acid compound reaction is present.

In the method for inhibiting the viscosity of the separation membrane, the product of the reaction of the bromine with the amine sulfonic acid compound is obtained by a method comprising the steps of: adding bromine to water, alkali and amine in a passive gas atmosphere. A mixture of sulfonic acid compounds to carry out the reaction.

In the method for inhibiting the viscosity of the separation membrane, the concentration of the trihalomethane precursor in the water supply or the washing water is preferably 0.001 mg/L or more in terms of the trihalomethane formation potential.

In the method for inhibiting the viscosity of the separation membrane, the separation membrane is preferably a polyamine-based polymer membrane.

In the method for inhibiting the viscosity of the separation membrane, the trihalomethane precursor is preferably a humus.

In the method for inhibiting the viscosity of the separation membrane, it is preferred that the water supply or the wash water further contains a bromide ion.

In the method for inhibiting the viscosity of the separation membrane, the concentration of the bromide ion in the water supply or the wash water is preferably 5 mg/L or more.

A method for suppressing a viscosity of a separation membrane, wherein the membrane separation device including the separation membrane is a membrane separation device capable of operating and stopping the membrane, and the membrane separation device is stopped during operation. a reaction product of the bromine-based oxidizing agent or the bromine compound and the chlorine-based oxidizing agent, and the bromine-based oxidizing agent or the reaction product of the bromine-based oxidizing agent and the chlorine-based oxidizing agent and the aminesulfonic acid compound are present, and the bromine-based oxidizing agent or The reaction product of the bromine compound with the chlorine-based oxidizing agent, the product reacted with the amine sulfonic acid compound, or the product of the reaction of the aforementioned bromine with the amine sulfonic acid compound is present.

In the method for inhibiting the viscosity of the separation membrane, the pH of the water present in the membrane separation device is preferably pH 5.5 or higher.

In the method for inhibiting the viscosity of the separation membrane, the water present in the membrane separation device is preferably at least one of seawater and alkaline water. [effect of the invention]

The present invention is based on the presence of a bromine-based oxidizing agent or a "reactant of a bromine compound and a chlorine-based oxidizing agent" in a water supply or washing water containing a membrane separation device equipped with a separation membrane containing a trihalomethane precursor; An oxidizing agent or a "reactant of a bromine compound and a chlorine-based oxidizing agent", and an amine sulfonic acid compound; and a product obtained by reacting a bromine-based oxidizing agent or a "reactant of a bromine compound with a chlorine-based oxidizing agent" with an aminesulfonic acid compound; By having a mixture of bromine and an amine sulfonic acid compound present; or by presenting a product in which bromine is reacted with an amine sulfonic acid compound, it has a sufficient viscosity inhibiting effect and at the same time reduces the trihalomethane content in the permeated water.

Hereinafter, embodiments of the present invention will be described. This embodiment is an example of the present invention, and the present invention is not limited to the embodiment.

<Method for inhibiting the viscosity of the separation membrane> The method for suppressing the viscosity of the separation membrane according to the embodiment of the present invention is a method of suppressing the viscosity of a separation membrane containing a trihalomethane precursor, and supplying a bromine system to a water supply or washing water containing a membrane separation device having a separation membrane. The oxidizing agent has a method as a viscosity inhibitor or a method in which a "reactant of a bromine compound and a chlorine-based oxidizing agent" such as hypobromous acid is present as a viscosity inhibitor.

The method for suppressing the viscosity of a separation membrane according to the embodiment of the present invention is to provide a "bromine oxidizing agent" and an "amine sulfonic acid compound" in a water supply or washing water containing a membrane separation device including a separation membrane containing a trihalomethane precursor. There is a method as a viscosity inhibitor, or a method in which a "reactant of a bromine compound and a chlorine-based oxidizing agent" and an "amine sulfonic acid compound" are present as a viscosity inhibitor. It is believed that a hypobromous acid stabilized composition is formed in the water or wash water.

Further, in the method for suppressing the viscosity of a separation membrane according to the embodiment of the present invention, a "bromine oxidizing agent is reacted with an amine sulfonic acid compound in a water supply or washing water containing a membrane separation device including a separation membrane containing a trihalomethane precursor. The hypobromous acid stabilized composition of the product of the product is a method of forming a viscosity inhibitor, or a hypobromous acid stabilized composition of a product of a reaction between a bromine compound and a chlorine-based oxidant and an amine sulfonic acid compound. There is a method as a stickin inhibitor.

Specifically, the method for suppressing the viscosity of the separation membrane according to the embodiment of the present invention is such as "bromine" or "chlorination" in a water supply or washing water containing a membrane separation device including a separation membrane containing a trihalomethane precursor. The method in which bromine, "phosphinic acid" or "reactant of sodium bromide and hypochlorous acid" exists.

In the method for suppressing the viscosity of a separation membrane according to the embodiment of the present invention, for example, "bromine", "bromine chloride", and "bromochloride" are provided in a water supply or washing water containing a membrane separation device having a separation membrane supplied with a trihalomethane precursor. A method in which hypobromous acid or a reaction product of sodium bromide and hypochlorous acid and an aminesulfonic acid compound exist.

Moreover, the method for suppressing the viscosity of the separation membrane according to the embodiment of the present invention is such that "the bromine reacts with the amine sulfonic acid compound in a water supply or washing water containing a membrane separation device including a separation membrane containing a trihalomethane precursor. Method for the presence of a hypobromous acid stabilized composition of a product, a product of a reaction of a bromine chloride with an amine sulfonic acid compound, or a product of a reaction of sodium bromide with hypochlorous acid and a product of an amine sulfonic acid compound . Further, although it is not expressified which compound is produced as "product of the reaction of bromine with an aminesulfonic acid compound", it is considered that "bromoaminesulfonic acid" which forms a hypobromous acid stabilizer compound is produced.

According to such a method, the occurrence of the viscosity of the separation membrane can be suppressed in the membrane separation apparatus using the water supply or the wash water containing the trihalomethane precursor, and the trihalomethane content in the permeated water can be lowered. Moreover, the film contamination by microorganisms can be reliably suppressed without deteriorating the performance of the separation membrane. According to the method for suppressing the viscosity of the separation membrane of the present embodiment, it is possible to have a high viscosity-suppressing effect and to perform a viscosity-suppressing treatment which minimizes the influence on the film properties and the water quality in the subsequent stage.

The bromine-based oxidizing agent and the hypobromous acid-stabilizing composition are also the same as the chlorine-based oxidizing agent, and react with the trihalomethane precursor to form a trihalomethane, which is considered to be formed by the bromine-based oxidizing agent and the hypobromous acid-stabilizing composition. The halomethane is mainly a bromine-based trihalomethane such as tribromomethane, and is more easily removed by a separation membrane than a chlorine-based trihalomethane such as chloroform which is produced by a chlorine-based oxidizing agent. Trihalomethanes are greatly reduced. Although the reason for the high exclusion rate of the bromine-based trihalomethane separation membrane is not known, it is presumed that the bromine-based trihalomethane phase has a relatively large molecular weight compared to the chlorine-based trihalomethane.

In this way, the method for suppressing the viscosity of the separation membrane of the present embodiment exhibits a viscosity-suppressing effect equal to or higher than that of a chlorine-based oxidizing agent such as hypochlorous acid, but the utilization of the bromine-based trihalomethane produced by the chlorine-based oxidizing agent is separated. The membrane removal rate is significantly higher, so the trihalomethane in the permeate water of the separation membrane can be greatly reduced. Therefore, the viscosity inhibitor used in the method for suppressing the viscosity of the separation membrane of the present embodiment is suitable as a viscosity inhibitor for a separation membrane.

In the method for suppressing the viscosity of the separation membrane of the present embodiment, a method in which a "bromine oxidizing agent" and an "amine sulfonic acid compound" are present, a "reactant of a bromine compound and a chlorine oxidizing agent", and an "amine sulfonic acid compound" A method of presenting a method of presenting a product of "a product of reacting a bromine-based oxidizing agent with an amine sulfonic acid compound" or a method of "a product of reacting a reaction product of a bromine compound with a chlorine-based oxidizing agent with an aminesulfonic acid compound" The effect of deterioration of the separation membrane is remarkably low, and it can directly flow into the separation membrane to suppress the viscosity. Therefore, the viscosity inhibitor used in these viscosity inhibition methods is suitable as a viscosity inhibitor for a separation membrane.

In the method for suppressing the viscosity of the separation membrane of the present embodiment, when the "bromine-based oxidizing agent" or the "reactant of the bromine-based compound and the chlorine-based oxidizing agent" is bromine, since the chlorine-based oxidizing agent is not present, the separation membrane is used. The production rate of the chlorine-based trihalomethane having a low rate is also low, and it is more suitable as a viscosity inhibitor for a separation membrane. When a chlorine-based oxidizing agent is contained, there is a concern that chloric acid is generated.

The trihalomethanes are those in which three hydrogen atoms of methane are substituted by halogen, and examples thereof include chloroform, bromodichloromethane, dibromochloromethane, and bromoform. The trihalomethane precursor is not particularly limited as long as it is a precursor of trihalomethane, and examples thereof include a compound having a 1,3-diketone structure and a compound having a 1,3-dihydroxybenzene structure. Wait. Specific examples of the trihalomethane precursor include humic substances including humic acid or fulvic acid. Here, the humus (humus plant) plant leaves or stems are partially humused, and the fraction precipitated by acid in the humus is called humic acid, and the fraction which is not precipitated is called yellow rot. acid.

For the trihalomethane precursor (THMFP) (mg/L), a measurement method based on the "special method for the preservation of the water quality of the water source of the waterway for the prevention of specific waterways and water barriers" can be used. Determination. Specifically, the sample is trapped in the gas phase by blowing air at a pH of 7.0, a temperature of 20 ° C, a reaction time of 24 hours, and a residual residual chlorine concentration of 1 to 2 mg/L after 24 hours. The method of simultaneous analysis of a mass spectrometer is carried out to determine the amount of trihalomethane generated. Further, the trihalomethane precursor may be measured by a TOC meter or the like.

If the trihalomethane precursor is present at a concentration of 0.001 mg/L or more in terms of trihalomethane formation potential (THMFP) (mg/L), trihalomethane is easily formed, so if the trihalomethane of the water supply or wash water of the membrane separation device is supplied When the production potential is 0.001 mg/L or more, preferably 0.01 mg/L or more, and more preferably 0.02 mg/L or more, the method for suppressing the viscosity of the separation membrane of the present embodiment is more effective. The upper limit of the trihalomethane formation potential of the water supply or wash water of the membrane separation device is not particularly limited, and is, for example, 1 mg/L or less.

Further, when the trihalomethane precursor is 0.5 mg/L or more in terms of TOC, trihalomethane is easily formed. Therefore, if the TOC of the water supply or the washing water of the membrane separation device is 0.5 mg/L or more, preferably 5.0 mg. When the pressure is at least 10.0 mg/L or more, the method for suppressing the viscosity of the separation membrane of the present embodiment is more effective. The upper limit of the TOC of the water supply or the wash water of the membrane separation device is not particularly limited, and is, for example, 500 mg/L or less. Further, in the case of the measurement described in the examples below, the trihalomethane formation potential of 0.01 mg/L corresponds to a TOC of 5.0 mg/L.

In particular, when the trihalomethane precursor contains humic acid, if the humic acid is present at 0.89 mg/L or more, trihalomethane is easily formed. Therefore, if the humic acid of the water supply or washing water supplied to the membrane separation device is 0.89 mg/L. In the above, it is preferably 8.9 mg/L or more, and more preferably 890 mg/L or more, and the method for suppressing the viscosity of the separation membrane of the present embodiment is more effective. The upper limit of the humic acid of the water supply or the wash water of the membrane separation device is not particularly limited, and is, for example, 180 mg/L or less. Further, in the case of the measurement described in the examples below, the trihalomethane formation potential of 0.01 mg/L corresponds to humic acid of 8.9 mg/L.

In the method for suppressing the viscosity of the separation membrane of the present embodiment, when the water supply or the washing water of the membrane separation device including the separation membrane further contains bromide ions, the effect is further exerted. According to the method for suppressing the viscosity of the separation membrane of the present embodiment, in the membrane separation apparatus using the water supply or the wash water containing the trihalomethane precursor and the bromide ion, the membrane has a sufficient viscosity suppressing effect and at the same time, the water permeability can be lowered. Trihalomethane content.

As described above, when a chlorine-based oxidizing agent such as hypochlorous acid is added to water containing a trihalomethane precursor, trihalomethane such as chloroform is formed, and bromide ions (for example, 5 mg/L or more) are contained in water such as seawater. Further, in the case of a trihalomethane precursor such as humus, when hypochlorous acid is added as a viscosity inhibitor, a bromine-based trihalomethane is mainly formed. Since the bromine-based trihalomethane has a larger molecular weight than the chlorine-based trihalomethane, it is larger in terms of the total trihalomethane concentration.

The viscous inhibitors such as "hypobromous acid" or "homobromic acid stabilized composition in which a bromine-based oxidizing agent and an amine sulfonic acid coexist" used in the method for suppressing the viscosity of the separation membrane of the embodiment of the present invention are The viscosity inhibition effect (bactericidal effect) of chloric acid equivalent or more. Further, when a trihalomethane precursor and a bromide ion are present in the system, a bromine-based trihalomethane is mainly formed. However, these "hypobromous acid" or "hypobromide stabilized composition" are different from ordinary hypochlorous acid, and there is almost no increase in the amount of trihalomethane generated with an increase in the concentration of the bromide ion. Therefore, it is considered that the method for suppressing the viscosity of the separation membrane of the present embodiment is based on a viscosity inhibitor such as a hypobromous acid or a brominated oxidizing agent and an aminesulfonic acid. In the case of bromide ion, the concentration of trihalomethane formed becomes lower than in the case of using hypochlorous acid.

On the other hand, "anti-hypochlorous acid" such as chloramine sulfonic acid is stabilized, so although it inhibits the trihalomethane formation potential, it is more bactericidal than "hypobromic acid" or "hypobromite stabilized composition". Low, unable to obtain sufficient viscosity inhibition effect.

The viscosity inhibitor used in the method for inhibiting the viscosity of the separation membrane of the present embodiment not only exhibits a viscosity-suppressing effect equal to or higher than that of hypochlorous acid, but also contains bromide ions in the treated water as compared with hypochlorous acid. Because of this, the amount of trihalomethane produced is small. Therefore, the method for suppressing the viscosity of the separation membrane of the present embodiment is suitable as a method for inhibiting the viscosity of a membrane separation apparatus using a water supply or washing water containing a trihalomethane precursor and a bromide ion.

As described above, the method for suppressing the viscosity of the separation membrane of the present embodiment can have a high viscosity-suppressing effect and at the same time achieve a viscosity-suppressing treatment that minimizes the concentration of the trihalomethane in the permeated water of the separation membrane.

In particular, if bromide ions are present in the water supply or washing water of the membrane separation device at a concentration of 5 mg/L or more, in the case of hypochlorous acid, trihalomethane is easily formed, so if the bromide ion of the water supply or wash water of the membrane separation device is supplied, When the concentration is 5 mg/L or more, preferably 18 mg/L or more, the method for suppressing the viscosity of the separation membrane of the present embodiment is more effective. The upper limit of the concentration of the bromide ion of the water supply or the wash water of the membrane separation device is not particularly limited, and is, for example, 1000 mg/L or less.

In the method for suppressing the viscosity of the separation membrane of the present embodiment, for example, in a water supply or washing water using a membrane separation device containing a water supply or a washing water containing a trihalomethane precursor, a bromine system is injected by an injection pump or the like. The oxidant or the "reactant of the bromine compound and the chlorine-based oxidizing agent" may be used. The "bromine compound" and the "chlorine oxidant" may be separately added to the water system, or the raw liquid may be mixed with each other and added to the water system.

For example, it is also possible to inject a "bromine-based oxidant" or a "bromine compound with a chlorine-based oxidant" in a water supply or a wash water using a membrane separation device containing a water supply or a wash water containing a trihalomethane precursor. "," and "amine sulfonic acid compound". The "bromine oxidizing agent" or the "reactant of the bromine compound and the chlorine oxidizing agent" and the "amine sulfonic acid compound" may be separately added to the water system, or the raw liquid may be mixed with each other and added to the water system.

Further, for example, a product of a reaction of a bromine-based oxidizing agent with an aminesulfonic acid compound may be injected into a water supply or washing water of a membrane separation device using a water supply or washing water containing a trihalomethane precursor. Or "a product of a reaction of a bromine compound with a chlorine-based oxidant and a reaction with an aminesulfonic acid compound".

The above-mentioned viscosity inhibitor added to the water supply or the wash water of the membrane separation device may be decomposed by a reducing agent or the like immediately before contacting the separation membrane.

According to the method for suppressing the viscosity of the separation membrane of the present embodiment, even in the membrane separation system in which the operation and the shutdown are performed, deterioration of the separation membrane can be suppressed, and the separation membrane can be effectively sterilized during the shutdown operation.

<Film Separation System> A schematic diagram of an example of a membrane separation system according to an embodiment of the present invention will be described with reference to Fig. 1 and a configuration thereof will be described. The membrane separation system 1 includes a raw water tank 10 and a membrane separation device 12.

In the membrane separation system 1 of Fig. 1, a raw water pipe 16 is connected to the inlet of the raw water tank 10. The outlet of the raw water tank 10 and the inlet of the membrane separation device 12 are connected to each other via the raw water supply pipe 18 via the pump 14. A seepage water pipe 20 is connected to the through water outlet of the membrane separation device 12, and a concentrated water pipe 22 is connected to the concentrated water outlet. A sterilizing agent supply pipe 24 is connected between the pump 14 in the raw water supply pipe 18 and the inlet of the membrane separation device 12.

The operation of the membrane separation system 1 of the present embodiment and the sterilization method of the separation membrane will be described.

The raw water to be treated is stored in the raw water tank 10 as needed, and then supplied to the membrane separation device 12 through the raw water supply pipe 18 by the pump 14. In the membrane separation device 12, membrane separation treatment (membrane separation treatment step) is carried out by separating the membrane. The permeated water (treated water) obtained by the membrane separation treatment is discharged through the permeated water pipe 20, and the concentrated water is discharged through the concentrated water pipe 22. The concentrated water can also be circulated to the raw water tank 10 or the raw water supply pipe 18.

For example, a sterilizing agent supply mechanism is provided between the pump 14 in the raw water supply pipe 18 and the inlet of the membrane separation device 12, and the raw material in the raw water tank 10 is passed through the water by the membrane separation device 12, and the sterilizing agent addition mechanism is passed. The sterilizing agent supply pipe 24 is added to the raw water by adding a sterilizing agent of a predetermined concentration. When the operation of the membrane separation system 1 is stopped, the pump 14 is stopped, and the sterilizing agent is allowed to exist in the membrane separation device 12 during the shutdown of the membrane separation system 1. Further, the sterilizing agent supply mechanism may be provided in the raw water supply pipe 18 or the raw water tank 10.

Further, the membrane separation device 12 allows the raw water in the raw water tank 10 to pass through water, and the sterilizing agent supply pipe 24 may be added to the raw water by the sterilizing agent supply pipe 24 to add a predetermined concentration of the sterilizing agent to the raw water to operate the membrane separation system 1. At the time of the stop, the sterilizing agent supply pipe 24 is added to the raw water through the sterilizing agent supply pipe 24, and the sterilizing agent is added to the raw water, and the pump 14 is stopped. The sterilizing agent is allowed to exist in the membrane separating device 12 during the stop operation of the membrane separation system 1. Inside.

Here, "stop operation" means a state in which treated water (permeate water) is not obtained in the membrane separation system 1.

Further, when the membrane separation device 12 is backwashed by using backwash water or using permeable water as the backwash water, a sterilizing agent may be added to the backwash water, and the sterilizing agent may be present in the stop operation of the membrane separation system 1. Inside the membrane separation device 12.

In the membrane separation system 1, a level switch may be provided in the raw water tank 10 to stop the operation if the water level in the raw water tank 10 detected by the level switch is lower than a predetermined height during operation. In the stop operation, the water level in the raw water tank 10 detected by the level switch is controlled to be higher than the predetermined height.

The method for suppressing the viscosity of the separation membrane of the present embodiment is to use a "bromine oxidizing agent" and an "amine sulfonic acid" as a sterilizing agent (viscosity inhibitor) in the shutdown operation of the membrane separation system 1 for performing the operation and the shutdown operation. The method of "the compound" is present in the membrane separation device 12, or the "reactant of the bromine compound and the chlorine-based oxidant" and the "aminesulfonic acid compound" are present in the membrane separation device 12. It is considered that a hypobromous acid stabilized composition is formed in the backwash water containing the sterilizing agent or the water containing the sterilizing agent.

Further, in the method for suppressing the viscosity of the separation membrane of the present embodiment, the bromine-based oxidizing agent and the amine sulfonic acid are used as a sterilizing agent (viscosity inhibitor) during the shutdown operation of the membrane separation system 1 for performing the operation and the shutdown. The hypobromous acid stabilized composition of the product of the compound reaction is present in the membrane separation device 12, or the hypobromous acid is stabilized by the "reaction of the bromine compound with the chlorine oxidant and the product of the amine sulfonic acid compound". A method in which the composition is present in the membrane separation device 12.

Specifically, in the method for suppressing the viscosity of the separation membrane of the present embodiment, for example, "bromine", "bromine chloride", "hypobromic acid" or the like in the shutdown operation of the membrane separation system 1 for performing the operation and the shutdown operation. A method in which a "reactant of sodium bromide and hypochlorous acid" and an "amine sulfonic acid compound" are present in the membrane separation device 12.

Further, in the method for suppressing the viscosity of the separation membrane of the present embodiment, in the shutdown operation of the membrane separation system 1 for performing the operation and the shutdown, for example, "product of the reaction of bromine with an aminesulfonic acid compound" and "bromine chloride" A method in which the hypobromous acid stabilized composition of the product of the reaction of the aminesulfonic acid compound or the product of the reaction of sodium bromide with hypochlorous acid and the product of the aminesulfonic acid compound is present in the membrane separation device 12.

According to these methods, in the membrane separation system 1 that performs the operation and the shutdown, the deterioration of the separation membrane of the membrane separation device 12 can be suppressed, and the separation membrane can be effectively sterilized during the shutdown operation. Further, the complicated additional equipment for periodically supplying the sterilizing agent can be eliminated, and the system can be simplified.

In the method for suppressing the viscosity of the separation membrane of the present embodiment, for example, in the shutdown operation of the membrane separation system 1 for performing the operation and the shutdown, the "bromine oxidizing agent" or the "bromine compound" may be used by the injection pump or the like. The reaction product with the chlorine-based oxidant and the "amine sulfonic acid compound" are injected into the water system. The "bromine oxidizing agent" or the "reactant of the bromine compound and the chlorine oxidizing agent" and the "amine sulfonic acid compound" may be separately added to the water system, or the raw liquid may be mixed with each other and added to the water system.

Further, for example, in the stop operation of the membrane separation system 1 for performing the operation and the shutdown, the "product of the reaction of the bromine-based oxidizing agent with the aminesulfonic acid compound" or the "bromine compound and the chlorine-based oxidizing agent" by the injection pump or the like may be used. The reactants, the product of the reaction with the amine sulfonic acid compound, are injected into the water system.

In the method for suppressing the viscosity of the separation membrane of the present embodiment, the ratio of the equivalent of the "amine sulfonic acid compound" to the equivalent of the "bromine oxidizing agent" or the "reactant of the bromine compound and the chlorine-based oxidizing agent" is 1 The above is preferable, and the range of 1 or more and 2 or less is more preferable. When the ratio of the equivalent of the "bromine oxidizing agent" or the "reactant of the bromine compound to the chlorine oxidizing agent" to the equivalent of the "amine sulfonic acid compound" is less than 1, the film may be deteriorated. If it is more than 2, the film may be produced. The situation of increased costs.

The effective halogen concentration of the contact separation membrane is preferably 0.01 to 100 mg/L in terms of effective chlorine concentration. When the amount is less than 0.01 mg/L, a sufficient viscosity suppressing effect may not be obtained. When the amount is more than 100 mg/L, the separation membrane may be deteriorated or the piping may be corroded.

Examples of the bromine-based oxidizing agent include bromine (liquid bromine), bromine chloride, bromic acid, bromate, and hypobromous acid.

Among these, the preparation of "bromine and aminesulfonic acid compound (mixture of bromine and aminesulfonic acid compound)" or "product of reaction of bromine with aminesulfonic acid compound" of bromine is used as compared with "hypochlorous acid, The preparation of the bromine compound and the amine sulfonic acid, and the preparation of the "bromine chloride and amine sulfonic acid", the amount of the trihalomethane formed is itself small, and the reverse osmosis membrane (RO membrane) or the like is not further deteriorated. A permeable membrane (RO membrane) is more suitable as a viscous inhibitor for a separation membrane such as a reverse osmosis membrane (RO membrane) because it has a small amount of leakage of an effective halogen permeating water.

That is, the method for suppressing the viscosity of the separation membrane according to the embodiment of the present invention is such that bromine and an aminesulfonic acid compound are present in a water supply or washing water containing a membrane separation device having a separation membrane containing a trihalomethane precursor. It is preferred to have a mixture of bromine and an amine sulfonic acid compound present. Further, it is preferred to have a product obtained by reacting bromine with an aminesulfonic acid compound in a water supply or washing water containing a membrane separation device having a separation membrane supplied with a trihalomethane precursor.

Examples of the bromine compound include sodium bromide, potassium bromide, lithium bromide, ammonium bromide, and hydrobromic acid. Among these, sodium bromide is preferred from the viewpoint of the cost of the preparation and the like.

Examples of the chlorine-based oxidizing agent include chlorine gas, chlorine dioxide, hypochlorous acid or a salt thereof, chlorous acid or a salt thereof, chloric acid or a salt thereof, perchloric acid or a salt thereof, and isocyanuric chloride or Salt and so on. In the above, examples of the salt include an alkali metal hypochlorite such as sodium hypochlorite or potassium hypochlorite, an alkali metal hypochlorite such as barium hypochlorite or barium hypochlorite, sodium chlorite, potassium chlorite, and the like. Alkaline metal salt of chlorite, alkali metal chlorite such as bismuth chlorite, other metal chlorite such as nickel chlorite, ammonium chlorate, sodium chlorate, potassium chlorate, etc., chloric acid An alkaline earth metal salt such as calcium or bismuth chlorate. These chlorine-based oxidizing agents may be used alone or in combination of two or more. As the chlorine-based oxidizing agent, those using sodium hypochlorite are preferred from the viewpoint of workability and the like.

The aminesulfonic acid compound is a compound represented by the following general formula (1). R ₂ NSO ₃ H (1) (wherein R is independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms).

As the amine sulfonic acid compound, for example, in addition to an amidosulfuric acid in which two of the two R groups are hydrogen atoms, N-methylaminesulfonic acid, N-ethylaminesulfonic acid, and N- may be mentioned. An aminesulfonic acid having one of two R groups, such as propylaminesulfonic acid, N-isopropylaminesulfonic acid or N-butylaminesulfonic acid, is a hydrogen atom and the other is an alkyl group having 1 to 8 carbon atoms. Compound, N,N-dimethylamine sulfonic acid, N,N-diethylamine sulfonic acid, N,N-dipropylamine sulfonic acid, N,N-dibutylamine sulfonic acid, N-methyl -N-ethylamine sulfonic acid, N-methyl-N-propylamine sulfonic acid, and the like, two R groups, both of which are amine sulfonic acid compounds having an alkyl group of 1 to 8 carbon atoms, N-phenylamine sulfonate An aminesulfonic acid compound in which one of two R groups such as an acid is a hydrogen atom and the other is an aromatic group having 6 to 10 carbon atoms, or the like. Examples of the amine sulfonate include alkali metal salts such as sodium salts and potassium salts, alkaline earth metal salts such as calcium salts, barium salts and barium salts, manganese salts, copper salts, zinc salts, barium salts, cobalt salts, nickel salts, and the like. Other metal salts, ammonium salts and barium salts. The amine sulfonic acid compound and the salt thereof may be used alone or in combination of two or more. As the amine sulfonic acid compound, those using sulfamic acid are preferred from the viewpoint of environmental load and the like.

In the method for inhibiting the viscosity of the separation membrane of the present embodiment, the base may be further present. Examples of the base include an alkali hydroxide such as sodium hydroxide or potassium hydroxide. From the viewpoint of product stability at a low temperature and the like, sodium hydroxide and potassium hydroxide can also be used in combination. Further, the base may be an aqueous solution instead of a solid.

Examples of the separation membrane include a reverse osmosis membrane (RO membrane), a nanofiltration membrane (NF membrane), a microfiltration membrane (MF membrane), and an ultrafiltration membrane (UF membrane). Among these, in particular, the method for suppressing the viscosity of the separation membrane according to the embodiment of the present invention can be suitably applied to a reverse osmosis membrane (RO membrane). Further, as the reverse osmosis membrane, the method for suppressing the viscosity of the separation membrane according to the embodiment of the present invention can be suitably applied to a polyimide-based polymer membrane which is currently in the mainstream. The polyamine-based polymer film has low resistance to an oxidizing agent, and when the free-chain chlorine or the like is continuously contacted with the polyamine-based polymer film, the film properties are remarkably lowered. However, the method for suppressing the viscosity of the separation membrane of the present embodiment hardly causes such a remarkable decrease in film properties even in the polyamide polymer film.

In the method for suppressing the viscosity of the separation membrane of the present embodiment, when the membrane separation device is an RO device including a reverse osmosis membrane (RO membrane) as a separation membrane, the pH of the water supply to the RO device is preferably 5.5 or more. More than 6.0 is better, and 6.5 or more is further better. If the pH of the water supply to the RO device is less than 5.5, the amount of the permeated water is lowered. In addition, the upper limit of the pH of the water supply to the RO device is not particularly limited as long as it is equal to or lower than the applicable upper limit pH (for example, pH 10) of the normal reverse osmosis membrane (RO membrane), and when scale deposition of a hardness component such as calcium is considered, The pH system is preferably operated at, for example, 9.0 or less. When the viscosity suppression method of the separation membrane of the present embodiment is used, the pH of the water supply to the RO apparatus is operated at 5.5 or more, and the deterioration of the reverse osmosis membrane (RO membrane) and the treated water (permeate water) are suppressed. The water quality deteriorates and the full viscosity inhibition effect is exerted, while ensuring sufficient water permeability.

In the RO device, when the water supply to the RO device generates scale at pH 5.5 or higher, the dispersant may be used in combination with the bromine-based oxidizing agent or the hypobromous acid-stabilizing composition in order to suppress scale. Examples of the dispersant include polyacrylic acid, polymaleic acid, and phosphonic acid. The amount of the dispersant to the water supply is, for example, in the range of 0.1 to 1,000 mg/L in terms of the concentration of the RO concentrated water.

In addition, in order to suppress the generation of scale by using a dispersing agent, for example, the Lanier index of the concentration of the cerium oxide in the RO concentrated water is not more than the solubility, and the Langelier index of the calcium scale is 0 or less. Operating conditions such as recovery rate of the device.

Examples of the use of the RO device include seawater desalination, drainage recovery, and the like.

<Binder Inhibitor Composition for Separation Membrane> The viscous inhibitor composition for a separation membrane of the present embodiment contains a "bromine oxidizing agent", a "reactant of a bromine compound and a chlorine oxidizing agent", and an "amine sulfonic acid compound". Further, it may further contain a base.

Further, the viscosity inhibitor composition for a separation membrane of the present embodiment contains a product of "a reaction product of a bromine-based oxidizing agent and an aminesulfonic acid compound" or a reaction product of a bromine compound and a chlorine-based oxidizing agent, and a reaction product with an aminesulfonic acid compound. Further, it may further contain a base.

The bromine-based oxidizing agent, the bromine compound, the chlorine-based oxidizing agent, and the aminesulfonic acid compound are as described above.

In the composition of the viscosity inhibitor for a separation membrane of the present embodiment, since the reverse osmosis membrane (RO membrane) or the like is not further deteriorated, the amount of leakage of the effective halogen to the membrane permeating water such as RO permeate water is small. A compound containing bromine and an amine sulfonic acid compound (containing a mixture of a bromine and an amine sulfonic acid compound), such as a bromine, an amine sulfonic acid compound, a mixture of a base and water, or a product containing a bromine and an amine sulfonic acid compound. For example, a product of a reaction of bromine with an amine sulfonic acid compound, a base, and a mixture with water are preferred.

The viscous inhibitor composition for a separation membrane of the present embodiment has a high oxidizing power and a high viscosity-resistance and a viscous peeling force, as compared with a chlorinated viscous inhibitor such as chloramine sulfonic acid. Significant film degradation is caused almost as much as hypochlorous acid with the same oxidizing power. At ordinary usage concentrations, the effect on film degradation can be substantially ignored. Therefore, it is most suitable for a separation inhibitor for a separation membrane such as a reverse osmosis membrane (RO membrane).

Since the viscosity inhibitor composition for a separation membrane of the present embodiment hardly penetrates the reverse osmosis membrane (RO membrane) unlike hypochlorous acid, there is almost no influence on the quality of the treated water. Further, since the concentration can be measured on site in the same manner as hypochlorous acid or the like, the concentration can be more accurately managed. In addition, it is considered that the viscous inhibitor composition for a separation membrane of the present embodiment reacts with a trihalomethane precursor to form a bromine-based trihalomethane, but is easily removed by a separation membrane, and the separation membrane is permeable to water. Trihalomethanes have been substantially reduced.

The pH of the composition is, for example, greater than 13.0, and more preferably greater than 13.2. When the pH of the composition is 13.0 or less, the effective halogen in the composition may become unstable.

The bromic acid concentration in the viscosity inhibitor composition for separation membrane is preferably less than 5 mg/kg. When the concentration of bromic acid in the composition of the viscosity inhibitor for separation membrane is 5 mg/kg or more, the concentration of bromate ions in the permeated water becomes high.

<Method for Producing Viscosity Inhibitor Composition for Separation Membrane> The viscosity inhibitor composition for a separation membrane of the present embodiment is a mixture of a bromine-based oxidizing agent and an aminesulfonic acid compound, or a mixed bromine compound and a chlorine-based oxidizing agent. The reactant and the amine sulfonic acid compound are obtained, and a base may be further mixed.

The method for producing a viscosity inhibitor composition for a separation membrane comprising a viscous inhibitor composition for a separation membrane containing a bromine and an amine sulfonic acid compound or a product containing a bromine and an amine sulfonic acid compound, comprising the steps described below It is preferred to add bromine to a mixture containing water, a base and an amine sulfonic acid compound to react it in a passive gas atmosphere; or to add bromine to water and alkali under a passive gas atmosphere And a step of mixing a mixture of amine sulfonic acid compounds. By adding it in a passive gas atmosphere to cause it to react or to add it in a passive gas atmosphere, the concentration of bromate ions in the composition is lowered, and the concentration of bromate ions in the permeated water such as RO permeate is changed. low.

The passive gas to be used is not limited, and at least one of nitrogen gas and argon gas is preferable from the viewpoint of production and the like, and nitrogen gas is preferable from the viewpoint of production cost and the like.

The oxygen concentration in the reactor when bromine is added is preferably 6% or less, more preferably 4% or less, further preferably 2% or less, and particularly preferably 1% or less. When the oxygen concentration in the reactor at the time of the reaction of bromine is more than 6%, the amount of bromic acid generated in the reaction system may increase.

The addition ratio of bromine is preferably 25% by weight or less based on the total amount of the composition, and more preferably 1% by weight or more and 20% by weight or less. When the addition ratio of bromine is more than 25% by weight based on the total amount of the composition, the amount of bromic acid generated in the reaction system may increase. If it is less than 1% by weight, there is a case where the germicidal power is inferior.

The reaction temperature in the case of adding bromine is preferably in the range of from 0 ° C to 25 ° C, and more preferably in the range of from 0 ° C to 15 ° C from the viewpoint of production cost and the like. When the reaction temperature at the time of adding bromine is more than 25 ° C, the amount of bromic acid generated in the reaction system may increase, and if it is less than 0 ° C, it may be frozen. [Examples]

The present invention will be described in more detail by way of the following examples and comparative examples, but the invention is not limited to the following examples.

In the case of using a hypobromous acid stabilized composition of a "product of the reaction of a bromine-based oxidizing agent with an aminesulfonic acid compound" as a viscosity inhibitor (Example 1), a reaction product of a "bromine compound and a chlorine-based oxidizing agent, and The case of the hypobromous acid stabilized composition of the product of the reaction of the amine sulfonic acid compound (Example 2), the case of using the "bromine oxidizing agent" (Example 3), and the hypochlorous acid using a general viscosity inhibitor In the case (Comparative Example 1), the trihalomethane concentration in the permeated water was compared with the effect on the performance of the reverse osmosis membrane (RO membrane).

[Preparation of Composition 1] Under a nitrogen atmosphere, liquid bromine was mixed: 16.9 wt% (wt%), aminesulfonic acid: 10.7 wt%, sodium hydroxide: 12.9 wt%, potassium hydroxide: 3.94 wt%, water: The remaining amount was used to prepare a composition. The pH of the composition 1 was 14, and the effective halogen concentration (concentration in terms of available chlorine) was 7.5% by weight. The detailed preparation method of the composition 1 is as follows.

In order to maintain the oxygen concentration in the reaction vessel at a rate of 1%, 1436 g of water and 361 g of sodium hydroxide were added and mixed by continuously injecting a sealed 2-liter beaker using a mass flow controller to control the flow rate of nitrogen gas, followed by addition. After 300 g of the amine sulfonic acid was mixed and maintained, the temperature of the reaction liquid was maintained at 0 to 15 ° C, and 473 g of liquid bromine was added thereto, and further 230 g of a 48% potassium hydroxide solution was added to obtain an amount relative to the entire composition. The composition 1 was used in the weight ratio of 10.7% of an aminesulfonic acid, 16.9% of bromine, and an equivalent ratio of an aminesulfonic acid to an equivalent of bromine of 1.04. The pH of the resulting solution was determined to be 14 by the glass electrode method. The bromine content of the resulting solution was measured by a method of redox titration using thiosulphate by conversion of bromine to potassium iodide to be 16.9%, which was 100.0% of the theoretical content (16.9%). In addition, the oxygen concentration in the reaction vessel at the time of the bromine reaction was measured by "Oxygen Monitor JKO-02 LJDII" manufactured by Jikco Co., Ltd. In addition, the bromic acid concentration is less than 5 mg/kg.

[Preparation of Composition 2] Mixed sodium bromide: 11% by weight, 12% aqueous sodium hypochlorite solution: 50% by weight, sodium sulfamate: 14% by weight, sodium hydroxide: 8% by weight, water: remaining amount, and a composition was prepared. . The pH of the composition 2 was 14, and the effective halogen concentration (concentration in terms of available chlorine) was 6% by weight. The detailed preparation method of the composition 2 is as follows.

17 g of water was added to the reaction vessel, and 11 g of sodium bromide was added thereto, and the mixture was stirred and dissolved. Then, 50 g of a 12% sodium hypochlorite aqueous solution was added and mixed, and then 14 g of sodium sulfamate was added thereto, and the mixture was stirred and dissolved, and then 8 g was added. The sodium hydroxide is stirred and dissolved to obtain the desired composition 2.

In addition, according to the method specified by the water channel sodium hypochlorite specification (JWWA K 120 2008), the content of chloric acid in the composition is determined by ion chromatography, and the composition is compared with the composition 2 (1100 mg/kg). The content of 1 is less (less than 50 mg/kg).

[Composition 3] A 9% by weight aqueous sodium hypobromide solution (Kanto Chemical, Deer Grade 1) was used as the composition 3.

[Composition 4] A 12% by weight aqueous sodium hypochlorite solution was used as the composition 4.

<Examples 1 to 3, Comparative Example 1, Reference Examples 1 and 2> Compositions 1 to 4 were respectively added to the raw water of the reverse osmosis membrane device under the following conditions, and the total amount of the water in the separation membrane was compared with that in the separation membrane. The trihalomethane concentration and the total trihalomethane utilization rate of the reverse osmosis membrane (RO membrane). As the raw water, the following simulated waters were used in Examples 1 to 3 and Comparative Example 1, and pure water was used in Reference Examples 1 and 2.

(Test conditions) ・Testing equipment: Flat membrane tester and separation membrane: manufactured by Nitto Denko Co., Ltd., polyamine-based polymer reverse osmosis membrane ES15 ・Operating pressure: 0.75 MPa ・ Raw water: Trihalomethane formation potential is 0.01 mg /L simulation water (added humic acid (manufactured by Wako Pure Chemical Industries, Ltd.) 8.9 mg/L as a trihalomethane precursor in pure water, TOC: 5 mg/L) or pure water/agent: with effective halogen concentration (effective chlorine Addition of the composition 1 to 4 in the case of the concentration of 3 mg/L. ・The pH of the raw water is adjusted so that the pH of the test water is 8 after the addition of the chemical. The test temperature is 25 ° C. ・The method for measuring the potential of trihalomethane generation: The sample was mixed with a blow trap gas chromatography mass spectrometer under conditions of pH 7.0, temperature 20 ° C, reaction time 24 hours, and 24 hours after the residual residual chlorine concentration was 1 to 2 mg/L. The analysis method was carried out to determine the amount of trihalomethane generated. For the air blowing device, "Tekmar Stratum" manufactured by TEKMAR, "Agilent, 7890" for gas chromatography, and "Agilent, 5975C" for mass spectrometry.・Measurement method of effective halogen concentration: Using a residual chlorine measuring device ("DR-4000" manufactured by Hach Co., Ltd.) and measuring by DPD method)

(Evaluation method) [Total trihalomethane concentration in RO water-passing water and total trihalomethane utilization rate of reverse osmosis membrane (RO membrane)] The addition of simulated water or pure water is shown in Table 1. The composition was 1 to 4, and the pH was adjusted to 8 to adjust to a water temperature of 25 ° C, and the water was circulated to the RO device. The total trihalomethane concentration (mg/L) in the RO water and RO water was measured after 4 hours. The removal rate (%) of the total trihalomethane utilization reverse osmosis membrane (RO membrane) was determined from the total trihalomethane concentration in the RO water supply and the RO permeated water. The results are shown in Table 1. Here, the total trihalomethane refers to four substances of chloroform, bromodichloromethane, dibromochloromethane and tribromomethane.

The total trihalomethane concentration is based on the method established by the Ministry of Health, Labour and Welfare (the Ministry of Health, Labour and Welfare Notice No. 261) based on the provincial regulations of the water quality standard. Synchronous analysis using a gas capture mass spectrometer The method is measured.

【Table 1】

Thus, Examples 1 to 3 have a sufficient viscosity suppressing effect as compared with Comparative Example 1, and at the same time, the trihalomethane content in the permeated water can be reduced. Further, in the case of using pure water as the reference examples 1 and 2 of the raw water, trihalomethane was hardly formed.

"Comparative test for the effect of reverse osmosis membrane (RO membrane) exclusion rate, effect on permeability, and oxidizing power" For the use of bromine oxidizing agents or "reactants of bromine compounds and chlorine oxidizing agents", and amine sulfonic acid compounds In the case, it is compared with the effect of the hypotonic membrane (RO membrane) exclusion rate, the influence on the permeated water, the oxidizing power, and the bactericidal power in the case of using a general viscosity inhibitor, hypochlorous acid or hypobromous acid.

The composition 1, 2, and 4 to 7 were added to the raw water of the reverse osmosis membrane device under the following conditions, and the influence on the exclusion rate of the reverse osmosis membrane (RO membrane), the influence on the permeated water, and the oxidizing power were compared.

[Composition 5] Each component of the composition 2 was separately added to water.

[Composition 6] A composition 6 containing bromine chloride, sodium sulfonate, and sodium hydroxide was used. The pH of the composition 6 was 14, and the effective halogen concentration (concentration in terms of available chlorine) was 7% by weight.

[Composition 7] Sodium bromide: 15% by weight, 12% aqueous sodium hypochlorite solution: 42.4% by weight was added to water, respectively.

(Test conditions) ・Testing equipment: Flat membrane test apparatus and separation membrane: manufactured by Nitto Denko Co., Ltd., polyamine-based polymer reverse osmosis membrane ES20 ・Operating pressure: 0.75 MPa ・ Raw water: Sagami original well water (pH 7.2, The conductivity is 240 μS/cm, and the bromide ion concentration is less than 1.0 mg/L. ・The chemical is added to the composition 1, 2, 4 to 7 in an effective halogen concentration (concentration in terms of available chlorine) to be 10 mg/L.

(Evaluation method) ・Effect of rejection rate of reverse osmosis membrane (RO membrane): conductivity exclusion rate after water supply on the 30th (%) (100-[transparent water conductivity/water supply conductivity] × 100) Effect on the permeated water: The effective chlorine concentration in the permeated water after the addition of the drug for 1 hour was measured by the DPD method using a residual chlorine measuring device ("DR-4000" manufactured by Hach Co., Ltd.) (in terms of effective chlorine conversion concentration, mg/L) ) Oxidation power: The oxidation-reduction potential (ORP) of the water supply after one hour was measured using a redox potential measuring device (Ammonia DKK, RM-20P ORP meter)

"Comparative Test of Sterilization Force" The composition was added to the simulated water under the following conditions, 1, 2, 4 to 7, to compare the bactericidal power.

(Test conditions) ・Water: A bouillon is added to the original well water of Sagami, and the simulated water and the chemical are adjusted so that the total number of bacteria is 10 ⁵ CFU/ml: the effective halogen concentration (concentration in terms of available chlorine) Addition of the composition 1, 2, 4 to 7 in a manner of 1 mg/L (measurement method of effective halogen concentration: using a residual chlorine measuring device ("DR-4000" manufactured by Hach Co., Ltd.) and measuring by DPD method)

(Evaluation method) ・The number of general bacteria after 24 hours after the addition of the drug was measured using the number of bacteria measurement kits (Biochecker TTC)

The test results are shown in Table 2.

【Table 2】

The compositions 1, 2, 5, and 6 maintain a high rejection ratio of the reverse osmosis membrane (RO membrane), and the effective halogen concentration (concentration in terms of available chlorine) of the permeated water is also low, and the oxidizing power and the sterilizing power are also high. Among the compositions 1, 2, 5, and 6, the composition 1 maintained the highest rejection ratio of the reverse osmosis membrane (RO membrane), and the effective halogen concentration (concentration in terms of available chlorine) of the permeated water was the lowest.

In the composition 4, although the oxidizing power and the sterilizing power are high, the exclusion rate of the reverse osmosis membrane (RO membrane) is lowered, and the effective halogen concentration (concentration in terms of available chlorine) of the permeated water is also high. Although the composition 7 has a high oxidizing power and a sterilizing power, the effective halogen concentration (concentrated in effective chlorine) of the permeable water is slightly higher.

"Comparative Experiment of Concentration of Bromine Acid Ion in Permeable Water" The concentration of bromate ions in the permeated water was compared by the presence or absence of nitrogen blowing during the preparation of the composition.

[Preparation of Composition 1'] In the same manner as the composition 1, liquid bromine was mixed in a nitrogen atmosphere: 17% by weight (% by weight), aminesulfonic acid: 10.7% by weight, sodium hydroxide: 12.9% by weight, and hydroxide. Potassium: 3.95 wt%, water: remaining amount, and the composition 1' was prepared. The pH of the composition 1' was 14, the effective halogen concentration (concentration in terms of available chlorine) was 7.5% by weight, and the concentration of bromic acid was less than 5 mg/kg.

[Preparation of Composition 8] Without blowing nitrogen gas, liquid bromine was mixed under the atmosphere: 17% by weight (wt%), aminesulfonic acid: 10.7% by weight, sodium hydroxide: 12.9% by weight, potassium hydroxide: 3.95. Weight %, water: remaining amount, Composition 8 was prepared. The pH of the composition 8 was 14, the effective halogen concentration (concentration in terms of available chlorine) was 7.4% by weight, and the concentration of bromic acid was 63 mg/kg.

(Test conditions) ・Testing equipment: Flat membrane test apparatus and separation membrane: manufactured by Nitto Denko Co., Ltd., polyamine-based polymer reverse osmosis membrane ES20 ・Operating pressure: 0.75 MPa ・ Raw water: Sagami original well water (pH 7.2, Conductivity: 240 μS/cm) ・Pharmaceuticals: Adding the composition 1', 8 so that the effective halogen concentration (concentration in terms of available chlorine) is 50 mg/L

(Evaluation method) ・ The concentration of bromate ion in the permeated water was measured by ion chromatography-postcolumn spectrophotometry.

The test results are shown in Table 3.

【table 3】

The composition 1' is a water supply, and the bromate ion concentration in the permeated water is less than 1 μg/L. The composition 8 has a higher concentration of bromate ions in the water supply and the permeate water than the composition 1'.

Next, in the case of using a hypobromous acid stabilized composition which is a product of a reaction of a bromine-based oxidizing agent and an aminesulfonic acid compound as a viscosity inhibitor (Example 4) and a bromine-based oxidizing agent (Example 5) In the case of hypochlorous acid stabilized composition using a general viscosity inhibitor (hypochlorous acid) (Comparative Example 2) and "product of reaction of hypochlorous acid with an amine sulfonic acid compound" (Comparative Example 3) The concentration of trihalomethane in the treated water is compared for the effect on the bactericidal performance.

[Composition 9] Composition 9 was prepared by mixing 12% aqueous sodium hypochlorite solution: 50% by weight, amine sulfonic acid: 10% by weight, sodium hydroxide: 8% by weight, and water: the remaining amount. The pH of the composition 9 was 14, and the effective halogen concentration (concentration in terms of available chlorine) was 6% by weight.

<Examples 4 and 5, Comparative Examples 2 and 3> Compositions 1, 3, and 4 were separately added to raw water under the following conditions, and the total trihalomethane concentration in the treated water was compared. As the raw water, the following simulated water was used.

(Test conditions) ・ Raw water: Simulated water (Additional humic acid (manufactured by Wako Pure Chemical Industries, Ltd.) 8.9 mg/L as a trihalomethane precursor and pure sodium bromide (manufactured by Kanto Chemical Co., Ltd.). 300 mg/L is added as a source of bromide ion. ・Pharmaceuticals: Adding composition 1, 3, and 4 so that the effective halogen concentration (concentration in terms of available chlorine) is 3 mg/L. In the test, the pH of the test water is 8 and the test temperature is 25 °C. ・The method of measuring the effective halogen concentration is measured by the DPD method using a residual chlorine measuring device ("DR-4000" manufactured by Hach Co., Ltd.).

(Evaluation method) [Total trihalomethane concentration in treated water] Compositions 1, 3, and 4 were separately added to the simulated water, and the pH was adjusted to 8 to adjust to a water temperature of 25 ° C, and stirred for 4 hours. The total trihalomethane concentration (mg/L) in the treated water was measured after stirring for 4 hours. The results are shown in Figure 2. Here, the total trihalomethane refers to four substances of chloroform, bromodichloromethane, dibromochloromethane and tribromomethane.

The total trihalomethane concentration is based on the method established by the Ministry of Health, Labour and Welfare (the Ministry of Health, Labour and Welfare Notice No. 261) based on the provincial regulations of the water quality standard. Synchronous analysis using a gas capture mass spectrometer The method is measured.

[Comparative Test of Sterilization Force] The compositions 1 and 9 were added to the simulated water under the following conditions to compare the bactericidal power.

(test conditions) ・Water: Simulated water and chemical agent adjusted to a normal bacteria concentration of 10 ⁵ CFU/ml in the original mold water of the Sagami original water: 1 mg/L in terms of effective halogen concentration (concentration in effective chlorine) The method of measuring the effective halogen concentration (measured by the DPD method using a residual chlorine measuring device ("DR-4000" manufactured by Hach Co., Ltd.))

(Evaluation method) ・The number of general bacteria after 24 hours after the addition of the drug was measured using the number of bacteria measurement kits (Biochecker TTC)

The test results are shown in Table 4.

【Table 4】

Thus, in Examples 4 and 5, compared with Comparative Examples 2 and 3, the formation of a viscosity in water containing a trihalomethane precursor and a bromide ion was suppressed, and formation of a trihalomethane was easily suppressed.

"The effective halogen concentration in the water containing the trihalomethane precursor is changed at any time" [Preparation of the composition 2] The composition prepared in the following order based on the contents described in JP-A-11-506139. The pH of the composition was 14, the effective halogen concentration (concentration in terms of available chlorine) was 5% by weight, and the concentration of bromic acid was 15 mg/kg. (1) 41.7 g of a 12% sodium hypochlorite solution was added to 27.0 g of a 40% by weight sodium bromide aqueous solution, followed by stirring. (2) A stabilization solution consisting of 56.0 g of pure water, 26.0 g of amine sulfonic acid, and 18.0 g of sodium hydroxide was prepared. (3) 31.3 g of the stabilization solution of (2) was added to the solution of (1) while stirring to obtain the desired composition 2'.

<Example 6 and Comparative Example 4> Under the conditions shown in Table 5, simulated seawater A having a potential of 0.11 mg/L in trihalomethane was added (the humic acid (manufactured by Wako Pure Chemical Industries, Ltd.) was added to 8.9 mg of artificial seawater. /L as a trihalomethane precursor, TOC: 5mg / L), or a simulated halo B with a trihalomethane formation potential of 0.04mg / L (add humic acid (made by Wako Pure Chemical Industries, Ltd.) 8.9mg / L in artificial seawater As a trihalomethane precursor, TOC: 5 mg/L), or a simulated halo C with a trihalomethane formation potential of 0.01 mg/L (add humic acid (manufactured by Wako Pure Chemical Industries, Ltd.) at 8.9 mg/L as pure water. For the halomethane precursor, TOC: 5 mg/L), the composition 1, the composition 2', or the composition 4 was added so as to be 10 mg/L of asCl ₂ or 5 mg/L of asCl ₂ as an effective halogen. The sodium hydroxide aqueous solution or the sulfuric acid aqueous solution was adjusted so that the pH of the test liquid became 8.4, and it was left to stand at room temperature (25 ° C) under light-shielding conditions, and the change of the total halogen concentration was measured. The results are shown in Table 5. In addition, the artificial seawaters A and B were prepared by dissolving each component in pure water so as to have a composition shown in Table 6 using artificial seawater (Aquamarine (registered trademark)). The trihalomethane formation potential was measured by the same method as in Example 1.

Further, the total halogen concentration (concentration in terms of available chlorine) was measured in the following order.

The effective halogen concentration is diluted with the sample, using Hach's multi-project water quality analyzer DR/4000 (in the case of full halogen concentration, the measurement item is "perchlorin"), using the effective chlorine method (DPD (diethyl-p-phenylenediamine) ))) Determination of 値 (mg / L asCl ₂ ). In addition, the effective halogen as used herein means the enthalpy measured by the effective chlorine measurement method (DPD method). The effective bromine concentration (mg/L asCl ₂ ) of the effective halogen concentration in terms of chlorine can be calculated from the effective chlorine concentration, and can be measured by the effective chlorine measurement method (DPD method) and multiplied by 2.25 (159.8 (g/). The molecular weight of chlorine (Cl ₂ ) was set to 70.9 (g/mol), and the molecular weight of bromine (Br ₂ ) was set to 159.8 (g/mol).

【table 5】

[Table 6]

In Table 5, by comparison of the examples and the comparative examples, it was found that the composition 1 and the composition 2' were compared with the composition 4, and the residual halogen was highly maintained over a long period of time, and the membrane separation device was stopped even for a long period of time. The separation membrane can be effectively sterilized. Here, by comparison of Comparative Examples 4-1 and 4-2 with Comparative Example 4-3, it is considered that the rate of decline of the total halogen concentration in the simulated seawaters A and B is larger than that of the simulated water C. Because hypochlorous acid reacts with bromide ions in simulated seawater, it changes to less stable hypobromous acid. On the other hand, by Examples 6-1, 6-2, and 6-4, the compositions 1, 2' of the hypobromous acid stabilized composition were compared with the composition 4, and the total halogen was suppressed even in the simulated seawater. The decrease in concentration. It is believed that the reason is that the stabilizing composition of hypobromous acid has a higher stability than the hypochlorous acid or hypobromous acid, and a part of the stabilizing composition of hypobromous acid reacts with the chloride ion in the artificial seawater. And the formation of extremely stable bond chlorine.

"Rejection rate of reverse osmosis membrane (RO membrane) after immersion storage of sterilizing agent solution, influence on the amount of permeated water" <Example 7> The conductivity of the membrane after immersion storage of the separation membrane in each sterilizing agent solution for 30 days was excluded. The results of the rate and the water retention rate are shown in Table 7.

(Test conditions) ・Separation membrane: manufactured by Nitto Denko Co., Ltd., polyamine-based polymer reverse osmosis membrane ES15 ・Test water: simulated seawater A or simulated seawater B or simulated water C ・Pharmaceutical: 10 mg/L asCl ₂ was added and the pH of the test water was adjusted to a predetermined pH using a sodium hydroxide aqueous solution or a sulfuric acid aqueous solution. • The immersion storage period of the separation membrane: 30 days. The immersion storage conditions: room temperature (25 ° C under light-shielding conditions) )

(Measurement method of the exclusion rate) ・Testing device: Flat membrane test device ・Operating pressure: 0.75 MPa ・ Raw water: Phase mold raw water (pH 7.2, conductivity: 24 mS/m) ・Conductivity exclusion rate [%]=100-[ Permeable water conductivity / water supply conductivity] × 100 ・ Permeate water retention rate [%] = [permeate water volume of the separation membrane stored in the test water / permeability of the new separation membrane] × 100

[Table 7]

In the case where the composition 4 is immersed in the separation membrane for a long period of time, the separation membrane is deteriorated, and the rejection rate is largely lowered. However, even if the components 1 and 2' are immersed and stored in the separation membrane for a long period of time, the rejection rate can be maintained high, and the film deterioration can be suppressed.

As described above, in the example in which the hypobromous acid stabilized composition was used, deterioration of the separation membrane was suppressed in the membrane separation system in which the operation and the shutdown were performed, and the separation membrane was effectively sterilized during the shutdown operation.

1‧‧‧ Membrane Separation System
10‧‧‧ original sink
12‧‧‧ membrane separation device
14‧‧‧
16‧‧‧ Raw water piping
18‧‧‧ Raw water supply piping
20‧‧‧Transparent water piping
22‧‧‧Concentrated water piping
24‧‧‧Fungicide supply piping

Fig. 1 is a schematic configuration diagram showing an example of a membrane separation system according to an embodiment of the present invention. Fig. 2 is a graph showing the total trihalomethane concentration (mg/L) in treated water with respect to the bromide ion concentration (mg/L) in the water to be treated in Examples 4 and 5 and Comparative Example 2.

no

Claims (13)

A method for inhibiting the viscosity of a separation membrane, characterized in that a bromine-based oxidant or a "reactant of a bromine compound and a chlorine-based oxidant" is supplied to a water supply or washing water containing a separation membrane of a separation membrane containing a trihalomethane precursor. presence. A method for inhibiting the viscosity of a separation membrane, characterized in that a bromine-based oxidant or a "reactant of a bromine compound and a chlorine-based oxidant" is supplied to a water supply or washing water containing a separation membrane of a separation membrane containing a trihalomethane precursor. And an amine sulfonic acid compound is present. A method for inhibiting the viscosity of a separation membrane, characterized in that a bromine-based oxidant or a "reactant of a bromine compound and a chlorine-based oxidant" is supplied to a water supply or washing water containing a separation membrane of a separation membrane containing a trihalomethane precursor. The product which reacts with the amine sulfonic acid compound is present. A method for inhibiting the viscosity of a separation membrane, characterized in that a mixture of bromine and an amine sulfonic acid compound, or a bromine and an amine sulfonic acid is provided in a water supply or washing water containing a membrane separation device having a separation membrane supplied with a trihalomethane precursor material. The product of the compound reaction is present. The method for inhibiting the viscosity of a separation membrane according to claim 4, wherein the product of the reaction of the bromine with the aminesulfonic acid compound is obtained by a method comprising the steps of: adding bromine in a passive gas atmosphere; A mixture containing water, a base, and an aminesulfonic acid compound is allowed to react. The method for inhibiting the viscosity of a separation membrane according to any one of claims 1 to 5, wherein the concentration of the trihalomethane precursor of the water supply or the wash water is 0.001 mg/at the trihalomethane formation potential. L or more. The method for inhibiting the viscosity of a separation membrane according to any one of claims 1 to 5, wherein the separation membrane is a polyamine-based polymer membrane. The method for inhibiting the viscosity of a separation membrane according to any one of claims 1 to 5, wherein the trihalomethane precursor contains humus. The method for inhibiting the viscosity of a separation membrane according to any one of claims 1 to 5, wherein the water supply or the wash water further contains a bromide ion. The method for inhibiting the viscosity of a separation membrane according to claim 9, wherein the concentration of the bromide ion in the water supply or the wash water is 5 mg/L or more. The method for inhibiting the viscosity of a separation membrane according to any one of claims 1 to 5, wherein the membrane separation device including the separation membrane is a membrane separation device capable of operating and stopping the operation, and the membrane separation device is When the operation is stopped, the bromine-based oxidizing agent or the "reactant of the bromine compound and the chlorine-based oxidizing agent" is present, and the bromine-based oxidizing agent or the "reactant of the bromine compound and the chlorine-based oxidizing agent" and the aminesulfonic acid compound are present. A product of the reaction of a bromine-based oxidizing agent or a "reactant of a bromine compound with a chlorine-based oxidizing agent" and an "aminesulfonic acid compound" or a product obtained by reacting the bromine with an aminesulfonic acid compound. The method for inhibiting the viscosity of a separation membrane according to claim 11, wherein the pH of the water present in the membrane separation device is pH 5.5 or higher. The method for inhibiting the viscosity of a separation membrane according to claim 10, wherein the water present in the membrane separation device is at least one of seawater and alkaline water.