KR20190073047A - The Cleaning Agent with Accelerator for Decomposition of Biofilm and Method of Producing the Same - Google Patents

Abstract

The present invention relates to a production method of a reverse osmosis membrane cleaning agent, which comprises the steps of: adding and reacting a chelating agent into water to produce a first mixed solution; adding and reacting a nonionic surfactant to the first mixed solution to produce a second mixed solution; and adding and reacting an alkali compound to the second mixed solution to produce a third mixed solution. The reverse osmosis membrane cleaning agent comprising a biofilm degradation accelerator produced according to the present invention comprises the nonionic surfactant for biofilm biodegradation and a chelating agent capable of separating microorganisms, thereby promoting effective decomposition and cleaning efficiency of the biofilm and reducing operating costs such as membrane replacement cost.

Description

TECHNICAL FIELD The present invention relates to a reverse osmosis membrane detergent including a biofilm decomposition promoter and a preparation method thereof,

TECHNICAL FIELD The present invention relates to a reverse osmosis membrane detergent and a method for producing the same, and more particularly, to a reverse osmosis membrane detergent including a biofilm decomposition promoter and a method for producing the same.

As industrial development and water resource depletion become more advanced in recent years, demand for industrial water is rapidly increasing. Of these, the desalination technology by the reverse osmosis membrane method is one of widely used water treatment techniques because of high energy efficiency and convenience. Accordingly, it is widely used for water treatment including desalination of seawater and nautical water, water purification, and reuse of wastewater.

However, this technique has a problem that film contamination (fouling) occurs in which the contaminants in the raw water adhere to the surface of the membrane to deteriorate the performance over a long period of time. Performance deterioration due to membrane contamination can be partially recovered by physical and chemical cleaning, but the membrane must be replaced in order to keep the production quantity constant.

The cleaning of the reverse osmosis membrane is generally performed when the membrane manufacturer changes the pressure, pressure, and water pressure of the membrane to 10-15%. Such a cleaning cycle is characterized by variation in the degree of contamination of the membrane, kind, and water quality of the feed water.

Generally, conventionally, as a method of cleaning a contaminated membrane, acid cleaning and alkaline cleaning are separately performed to remove contaminants. First, the acid cleaning is carried out with an inorganic acid or an organic acid at a pH of 2 to 4 to remove the inorganic scale. However, the cleaning condition is changed depending on the contamination state of the membrane, and the temperature is raised to 35 to 40 to raise the cleaning effect, Respectively.

After the acid cleaning is finished, all of the washing waste liquid is discharged from the washing tank, sufficiently washed with water so that remaining acid remains, and then subjected to alkali washing again. Alkali compounds such as caustic soda are usually used for alkali cleaning. In order to increase the cleaning effect, the cleaning liquid is heated to raise the cleaning liquid to raise the cleaning effect. After the cleaning, the entire waste liquid is completely drained and sufficiently washed with water to complete the cleaning operation.

Therefore, in the conventional cleaning method, acid cleaning and alkaline cleaning are carried out respectively, which not only complicates the cleaning operation but also generates a large amount of cleaning waste liquid, and also has a disadvantage in that the amount of cleaning water to be used is large in accordance with each washing. In addition, the conventional cleaning method requires a large amount of electric power due to the use of steam for maintaining the temperature continuously for a long time during the cleaning process and the pump operation for circulating the washing water. Thus, the increase of the electric power cost and the long working time And so on.

As a conventional cleaning agent for reverse osmosis membrane, U.S. Pat. No. 4,496,470 discloses a cleaning agent which is buffered by monophosphate and phosphoric acid in an organic acid composed of citric acid and malic acid, which can be applied to contamination of iron and organic matters as well as calcium and magnesium scales, -4 < / RTI > and a non-ionic surfactant as a penetrant. However, the detergent described herein can only remove inorganic scale and can remove some microorganisms with a nonionic surfactant, but the effect thereof is insufficient, so that an additional alkali cleaning capable of cleaning the organic material is required.

U.S. Patent No. 4,806,259 discloses a membrane cleaner to which organic phosphoric acid, a surfactant and a flame retardant are added to the above-mentioned organic acid so as to be effective for the metal oxide and the silica scale. However, only the acid cleaning of the clay and the microorganism It is not effective to clean contaminated membranes. U.S. Patent No. 4,895,658 adds acrylic acid and methacrylic homopolymer to the detergent as a dispersant. Such a membrane cleaning method is mainly based on an organic acid, so that the organic matter of the clay and the microbial body are not dissolved and thus the cleaning effect is low. In order to remove such organic matter, an alkali washing is required as a separate process.

In particular, since an acid is used for removing inorganic substances and an alkali is used for organic matter removal, there is a disadvantage in that the following alkali washing operation must be performed after sufficient washing with water so that residual acid does not necessarily exist after acid washing. As a method of cleaning a reverse osmosis membrane.

As a conventional cleaning method of the reverse osmosis membrane, acid cleaning and alkali cleaning are respectively performed. However, the cleaning effect is insufficient for the film contaminated with the clay and the microorganisms, and the cleaning time is long. After the acid cleaning and before the alkali cleaning, It is necessary to sufficiently wash water so that there is no remaining acid, and thus, a large amount of washing water is consumed and a large amount of waste water is generated due to the washing water. Further, when washing the membrane, the electric power for driving the steam and the circulation pump for raising the temperature of the cleaning liquid in each of the steps is consumed, and a large amount of work force required for cleaning is required. Therefore, in order to solve such a problem, a rapid cleaning agent effective for cleaning clay and microorganisms and a cleaning method using the same are required to be continuously developed.

Patent Document 1: US Patent Publication No. 2009-0127212 Patent Document 2: Korean Patent No. 10-1078046

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made to solve the above problems, and it is an object of the present invention to provide a reverse osmosis membrane cleaning agent comprising a nonionic surfactant capable of effectively decomposing microorganisms and a chelating agent capable of separating microorganisms, and a method for producing the same. .

According to an aspect of the present invention, there is provided a method of preparing a mixed solution, comprising: preparing a first mixed solution by adding a chelating agent to water and reacting the mixed solution; Adding a nonionic surfactant to the first mixed solution and reacting the mixture to prepare a second mixed solution; And introducing an alkaline compound into the second mixed solution and reacting the mixed solution to prepare a third mixed solution.

The water may be 40 to 80 parts by weight based on 100 parts by weight of the cleaning agent.

The chelating agent may be 10 to 30 parts by weight based on 100 parts by weight of the detergent.

The chelating agent may be at least one selected from the group consisting of ethylenediaminetetraacetic acid salts (EDTA), aminocarboxylic acid salts, and nitrilo triacetate.

The nonionic surfactant may be 3 to 10 parts by weight based on 100 parts by weight of the cleaning agent.

The nonionic surfactant may be at least one selected from the group consisting of poly (alkylene-oxide) black co-polymers, oligomeric alkyl poly (ethylene oxide), and Sorbitan esters.

The alkali compound may be 1 to 7 parts by weight based on 100 parts by weight of the cleaning agent.

The alkali compound may be at least one selected from potassium hydroxide and caustic soda.

According to another aspect of the present invention, there is provided a method for producing a chelating agent, comprising: 10 to 30 parts by weight of a chelating agent; 3 to 10 parts by weight of a nonionic surfactant; 1 to 7 parts by weight of an alkali compound and water as a remainder are provided.

The chelating agent may be at least one selected from the group consisting of ethylenediaminetetraacetic acid salts (EDTA), aminocarboxylic acid salts, and nitrilo triacetate.

The nonionic surfactant may be at least one selected from the group consisting of poly (alkylene-oxide) black co-polymers, oligomeric alkyl poly (ethylene oxide), and Sorbitan esters.

The alkali compound may be at least one selected from potassium hydroxide and caustic soda.

The reverse osmosis membrane cleaner including the biofilm decomposition promoter manufactured according to the present invention includes a nonionic surfactant for decomposing biofilm and a chelating agent capable of separating microorganisms, thereby promoting effective decomposition and cleaning efficiency of the biofilm, It is possible to reduce operating costs such as costs.

FIG. 1 shows changes in flux recovery (%) and salt removal rate (%) in Examples and Comparative Examples according to time changes of the reverse osmosis membrane exposed to contaminants including humic acid.

Hereinafter, preferred embodiments of the present invention will be described with reference to various embodiments. However, the embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below.

The present invention relates to a reverse osmosis membrane cleaner including a biofilm decomposition promoter and a method for producing the same.

According to an aspect of the present invention, there is provided a method of preparing a mixed solution, comprising: preparing a first mixed solution by adding a chelating agent to water and reacting the mixed solution; Adding a nonionic surfactant to the first mixed solution and reacting the mixture to prepare a second mixed solution; And introducing an alkaline compound into the second mixed solution and reacting the mixed solution to prepare a third mixed solution.

The process for preparing a reverse osmosis membrane cleaner of the present invention starts with the step of adding a chelating agent to water and reacting to prepare a first mixed solution.

The water is preferably 40 to 80 parts by weight, more preferably 50 to 70 parts by weight, based on 100 parts by weight of the cleaning agent. When the amount of the chelating agent is less than 40 parts by weight, dissolution of the chelating agent may be difficult, resulting in a problem in stability of the product. If the amount is more than 80 parts by weight, the amount of the chelating agent in the product may increase.

Because the chelating agent has a strong negative charge, the positive charge in the contaminant can be strongly attracted to destroy the bond and remove contaminants. The chelating agent to be used in the present invention is not particularly limited and includes, for example, polymerized phosphates including sodium tripolyphosphate, ethylenediaminetetraacetic acid salts (EDTA) having a carboxyl group, nitrilotriacetic acid salts nitrilo triacetate, hydroxyethylenediamine triacetate, and the like. Preferably, a polymerized phosphate containing sodium tripolyphosphate may be used.

The chelating agent is preferably 10 to 30 parts by weight, more preferably 15 to 25 parts by weight, based on 100 parts by weight of the cleaning agent. If the amount of the chelating agent is less than 15 parts by weight, the amount of the chelating agent to be added may be increased to increase the operation cost. If the amount of the chelating agent is more than 30 parts by weight, the chelating agent may be difficult to dissolve.

The step of preparing the first mixed solution may be performed for 5 to 30 minutes, preferably 10 to 20 minutes.

Next, a nonionic surfactant is added to the first mixed solution and reacted to prepare a second mixed solution. This is because the amide material of the PA membrane has a (-) charge, so nonionic surfactants are used because cationic surfactants can be used as contaminants when used.

The nonionic surfactant is preferably 3 to 10 parts by weight, more preferably 5 to 8 parts by weight, based on 100 parts by weight of the cleaning agent. When the amount of the nonionic surfactant is less than 3 parts by weight, the effect of the nonionic surfactant decreases, while when the amount of the nonionic surfactant is more than 10 parts by weight, it is difficult to dissolve the nonionic surfactant.

The nonionic surfactant used in the present invention is not particularly limited. For example, poly (alkylene-oxide) black co-polymers, oligomeric alkyl poly (ethylene oxide) Poly (alkylene-oxide) black co-polymers can be used.

The step of preparing the second mixed solution may be performed for 5 to 30 minutes, preferably 10 to 20 minutes.

Next, an alkaline compound is added to the second mixed solution and reacted to prepare a third mixed solution to obtain a reverse osmosis membrane cleaner.

The alkali compound is preferably 1 to 7 parts by weight, more preferably 1 to 5 parts by weight, based on 100 parts by weight of the cleaning agent. In particular, when the amount of the nonionic surfactant is more than 7 parts by weight, the pH of the product may increase, resulting in deterioration of the functionality of the nonionic surfactant.

Alkali compounds are effective components for decomposing organic components by generating hydroxy ions in water to break oxygen and oxygen bonds in the fat molecule structure. The alkali compound used in the present invention is not particularly limited, but for example, caustic soda, ammonia and hydrazine can be used, and caustic soda can be preferably used.

The step of preparing the third mixed solution may be performed for 5 to 20 minutes, preferably 10 to 15 minutes.

In addition, the method for preparing the reverse osmosis membrane cleaning agent of the present invention can be performed at room temperature.

According to another aspect of the present invention, there is provided a method for producing a chelating agent, comprising: 10 to 30 parts by weight of a chelating agent; 3 to 10 parts by weight of a nonionic surfactant; 1 to 7 parts by weight of an alkali compound and water as a remainder are provided.

Since the reverse osmosis membrane cleaning agent according to the present invention includes a nonionic surfactant capable of effectively decomposing microorganisms and a chelating agent for separating microorganisms, it is excellent in cleaning effect against microorganisms and is used as an organic chemical cleaning agent, And the like can be reduced.

Example

Hereinafter, the present invention will be described in more detail with reference to examples. The following examples are intended to further illustrate the present invention and are not intended to limit the present invention.

Example

62.1 g of deionized pure water (H ₂ O) was added to the reactor and then continuously stirred. 18 g of ethylenediaminetetraacetic acid salts (EDTA) as a chelating agent was added to the reactor and the mixture was stirred for 15 minutes Liver reaction. Then, 7.2 g of poly (alkylene-oxide) black co-polymers, which is a nonionic surfactant, was added to the reactor and reacted for 20 minutes. 2.7 g of caustic soda as an alkali compound was added to the reactor and reacted for 10 minutes. The reaction was terminated after 1 hour of holding, and a washing liquid was obtained.

Comparative Example

A cleaning liquid was prepared in the same manner as in Production Example 1, except that 7.2 g of pure water was further mixed in place of 7.2 g of the nonionic surfactant.

Test Example

The reverse osmosis membrane contaminated with organics and microorganisms including humic acid was tested for cleaning. The reverse osmosis membrane used was LG Chem BW-400R, which was used for one year to desalinate the industrial water. As a result of analyzing the contaminants, the contaminants were attached at 1.89 g / m ² , and the ignition loss was 89.8 wt% Organic matter including microorganisms, and the rest was inorganic matter. As a result of converting the inorganic matter into EDX analysis, it was found that CaCO ₃ was 8.7% by weight and Fe ₂ O ₃ was 3.3% by weight.

The cleaning effect test was carried out using the cleaning liquid prepared according to Examples and Comparative Examples. Cleaning experiments were performed at 35 and were performed using an 8 inch reverse osmosis membrane pilot test instrument. The experiment was carried out by circulating for 30 minutes, immersing for 1 hour, recirculating for 30 minutes, and washing after 3 weight% of washing liquid was added. The cleaning efficiency was expressed by the percentage of the flux before cleaning and the difference of flux after cleaning as shown in the following formula 1. The results are shown in Table 1.

Cleaning efficiency (%) = (Flux after cleaning - Flux before cleaning) / Flux after cleaning x 100 (Equation 1)

In addition, the difference in salt removal rate was compared and the results are shown in Table 2. The cleaning efficiency was expressed as a percentage by using the replenishment water conductivity, the production water conductivity, the replenishment water conductivity after cleaning, and the production water conductivity before washing.

Salt removal rate (%) = (production water conductivity / water supply conductivity) x 100 (formula 2)

Example Comparative Example Flux before cleaning 9.83 9.83 Flux after cleaning 11.50 11.15 Cleaning efficiency (%) 14.53 11.83

Example Comparative Example Removal rate of washing salt (%) 94.53 94.53 After washing, the water supply conductivity 48.7 48.7 After washing, the production water conductivity 1.7 2.3 Salt Removal Rate after Cleaning (%) 96.72 95.54

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be obvious to those of ordinary skill in the art.

Claims (12)

Adding a chelating agent to water and reacting to prepare a first mixed solution;
Adding a nonionic surfactant to the first mixed solution and reacting the mixture to prepare a second mixed solution; And
And introducing an alkaline compound into the second mixed solution and reacting the alkaline compound to produce a third mixed solution.
The method according to claim 1,
Wherein the water is 40 to 80 parts by weight based on 100 parts by weight of the cleaning agent.
The method according to claim 1,
Wherein the chelating agent is 10 to 30 parts by weight based on 100 parts by weight of the detergent.
The method according to claim 1,
Wherein the chelating agent is at least one selected from the group consisting of ethylenediaminetetraacetic acid salts (EDTA), aminocarboxylic acid salts, and nitrilo triacetate.
The method according to claim 1,
Wherein the nonionic surfactant is 3 to 10 parts by weight based on 100 parts by weight of the cleaning agent.
The method according to claim 1,
Wherein the nonionic surfactant is at least one selected from poly (alkylene-oxide) black co-polymers, oligomeric alkyl poly (ethylene oxide), and sornitan esters.
The method according to claim 1,
Wherein the alkaline compound is 1 to 7 parts by weight based on 100 parts by weight of the cleaning agent.
The method according to claim 1,
Wherein the alkaline compound is at least one selected from potassium hydroxide and caustic soda.
10 to 30 parts by weight of a chelate; 3 to 10 parts by weight of a nonionic surfactant; 1 to 7 parts by weight of an alkali compound, and water as the balance.
10. The method of claim 9,
Wherein the chelating agent is at least one selected from the group consisting of ethylenediaminetetraacetic acid salts (EDTA), aminocarboxylic acid salts, and nitrilo triacetate.
10. The method of claim 9,
Wherein the nonionic surfactant is at least one selected from poly (alkylene-oxide) black co-polymers, oligomeric alkyl poly (ethylene oxide), and sornitan esters.
10. The method of claim 9,
Wherein the alkali compound is at least one selected from potassium hydroxide and caustic soda.

Images