JPH0760236A - Removal system of organic substance dissolved in water - Google Patents

Abstract

PURPOSE:To efficiently remove organic halogen substances dissolved in water by forming a leading-in inlet and a leading-out outlet to run an aqueous solution containing volatile dissolved organic substances in a space between a hollow fiber membrane and a container and forming a gas discharging outlet to discharge a gas in a hollow part of the hollow fiber membrane. CONSTITUTION:An aqueous solution containing volatile organic substances is led through a leading-in inlet 12, passes an apparatus 3 for removal of organic substances volatile in water and a hollow fiber membrane module 4 and flows out of a faucet, wherein the removal apparatus 3 is composed of an absorbent 2, a module 6 for removal of organic substances dissolved in water, and a pressure decreasing apparatus 7. The module 6 for removal of organic substances dissolved in water has diaphragms to separate spaces communicating with the hollow parts of hollow fiber membranes and spaces communicating with the outer surfaces of the hollow fiber membranes and space are partitioned by the outer surfaces of the hollow fiber membranes and the inner wall face of a container and an inlet and an outlet to run an aqueous solution containing dissolved organic substances, a discharging outlet to discharge gas in the spaces and a gas suction inlet to take in air out of the container, and a gas sucking and discharging mouth to suck and discharge a gas in the hollow parts of the hollow fiber membranes are formed in the module.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to volatile organic substances dissolved in tap water or well water (particularly trihalomethanes such as chloroform, dichlorobromoform, chlorodibromoform and broloform, 1,1,1-trichloroethane, 1,2,1).
A volatile organic halogen substance such as dichloroethane, trichlorethylene, tetrachloroethylene, etc.) to provide safe drinking water or highly pure water.

[0002]

2. Description of the Related Art In recent years, there has been a tendency to use a large amount of chlorine for sterilization or purification with an increase in the concentration of organic substances in river water, and carcinogenicity or mutagenicity generated by the reaction of chlorine with organic substances. The problem is that the concentration of trihalomethanes (organic substances in which three halogen substances are bonded to carbon such as chloroform) increases and the trace amount is dissolved in tap water.

In addition, carcinogenic organic halogen substances such as 1,1,1-trichloroethane, 1,2-dichloroethane, trichloroethylene, and tetrachloroethylene permeate underground into the well water as a degreasing agent for dry cleaning and machinery. Inclusion is also a problem at the same time.

Further, it is very dangerous that even a trace amount of these organic halogen substances is present in industrial water for foods and medicines, and in the industry in this field, a technique for removing a trace amount of organic halogen substances dissolved in water. Is long-awaited.

As a conventional method for removing volatile organic substances (in particular, organic halogen substances) dissolved in water, an adsorption treatment method for adsorbing organic substances on activated carbon or the like, or decomposition by light using a semiconductor catalyst such as titanium oxide Photo-decomposition method, iron and other metal components serve as a reduction catalyst to convert trichlorethylene to chlorine ion and chemically stable ethylene gas, a reduction method, a biological treatment method that decomposes by living organisms such as activated sludge, and a large amount in water. Aeration method to expel volatile organic substances dissolved in the liquid phase to the gas phase side by moving them from the gas partial pressure difference to expel them as gas or boil to expel the volatile organic substances dissolved in water to the gas phase side by boiling. The law is known.

On the other hand, as a method for efficiently removing oxygen dissolved in an aqueous solution, a method of degassing by using a tube or a hollow fiber membrane (JP-A-57-165007, JP-A-6-167007).
No. 0-25514), degassing method and apparatus using composite membrane (Jpn. Pat. Appln. KOKAI No. 3-7908, JP-A-3-16930).
No. 3, each gazette) is proposed.

[0007]

The adsorption treatment method has the object of not only increasing the cost because it cannot adsorb more than the adsorption capacity of the adsorbent and must be used in a large amount or must be reactivated. When a substance having a higher adsorption capacity than the removal substance is present in the vicinity of the adsorbent, the target removal substance may be released and may be adsorbed with the substance having a higher adsorption power. Furthermore, since the bactericidal agent is removed from the water after the adsorbent, there is a problem that various bacteria such as microorganisms are easily propagated.

The object of the present invention is to install a device for removing volatile organic substances from the adsorbent, which has released the target substance to be removed, after the adsorbent, to efficiently remove organic halogen substances dissolved in water, and to stabilize for a long period of time. Another object of the present invention is to provide a compact system for removing dissolved organic matter in water, which has excellent removal performance and is provided with a filter for removing fine particles such as iron rust and bacteria present in water.

[0009]

Means for Solving the Problems The gist of the present invention is to support a container, a hollow fiber membrane positioned in the container, and an end portion of the hollow fiber membrane after adsorbing chlorine and a high molecular weight organic compound, It has a partition wall that separates a space communicating with the hollow portion of the hollow fiber membrane and a space communicating with the outer surface of the hollow fiber membrane, and volatilizes in a space formed by the outer surface of the hollow fiber membrane and the inner wall surface of the container. Inlet and outlet for flowing an aqueous solution containing organic dissolved organic matter, or an exhaust outlet for exhausting gas in the space and an inlet for taking in air outside the container into the space, and a gas in the hollow portion of the hollow fiber membrane. A water-dissolved organic substance removal module provided with an exhaust port for exhausting air and an inlet port for taking in air outside the container into the hollow portion or an inlet port and an outlet port for flowing an aqueous solution containing a volatile organic substance. , A filter for removing fine particles existing in water The in-water dissolved organic matter removal system comprising attached.

FIG. 1 is a flow chart of the system for removing dissolved organic matter in water according to the present invention. An aqueous solution containing a volatile organic substance is introduced from an inlet 1, passes through an adsorbent 2, a volatile organic substance removing device 3 in water, a hollow fiber membrane module 4,
Supplied through the mouthpiece 5. The in-water dissolved volatile organic substance removing device 3 includes an in-water dissolved organic substance removing module 6 and a pressure reducer (intake blower) 7.

The hollow fiber membrane used in the module for removing dissolved organic matter in water may be a hydrophobic porous membrane having a pore size of 0.05 μm or less, but if it is used for a long time, water vapor leaks out, and as a result, water becomes porous. Since there is a risk of leakage from the quality film, a homogeneous film (A) with a film thickness of 8 μm or less
And a porous membrane (B) having a reinforcing function, wherein the homogeneous membrane (A) and the porous membrane (B) are alternately laminated and contact with the aqueous solution of the multilayer composite hollow fiber membrane. The layer on the side is a homogeneous membrane (A) or a porous membrane (B), the layer on the side not in contact with the aqueous solution is a porous membrane (B), and the chloroform permeation rate of the composite hollow fiber membrane is 1 x 1
0 ^-3 (cm ³ (STP) / cm ² / sec / cmHg)
A hollow fiber membrane having the above-mentioned permeation performance is preferable.

Chloroform transmission rate is 1 × 10 ^-3 (cm
^If it is less than ³ (STP) / cm ² / sec / cmHg), the permeation rate of permeation through the composite film of the organic substance dissolved in water is slow and the organic substance cannot be removed efficiently.

Materials for forming the porous layer of such a composite membrane include polyethylene, polypropylene and poly 3-.
Polyolefins such as methylbutene-1, poly-4-methylpentene-1 and vinylidene fluoride, fluorine-based polymers such as polytetrafluoroethylene, polymers such as polysulfone, polyetheretherketone and polyetherketone can be used. Polyolefin, which is a crystalline polymer capable of easily forming a porosity, is preferable.

The materials used for the homogeneous layer of the composite film include segmented polyurethane, silicone polymer,
Although low density polyethylene, polyolefin such as poly-4-methylpentene-1 and polyacrylamide can be considered, a polymer having a high affinity with an organic halogen substance is preferable.

Such a composite membrane is disclosed, for example, in Japanese Examined Patent Publication No. 3-44.
According to the method described in Japanese Patent No. 811 and the like, a polymer forming a homogeneous film A and a polymer forming a porous film B are alternately arranged by using a multi-cylindrical spinning nozzle, and melt-spun, and then the homogeneous film A. Porous Membrane B Without Making Porous
It is produced by a method of stretching under the condition that only the material is made porous.

[0016]

According to the organic substance removal system of the present invention, problems such as re-elution caused by a decrease in removal ability of a water purifier using an adsorbent due to long-term use are caused by the permanent dissolution of volatile organic substances in water in the rear part. By installing a removing device capable of removing, it is possible to stably supply water with a small amount of volatile organic substances, and it is also possible to remove fine particles such as iron rust and bacteria present in the water.

[0017]

EXAMPLES The present invention will be specifically described below based on examples. Example 1 A system shown in FIG. 1 was created. The composite hollow fiber membrane of the water-dissolved organic matter removal module has a three-layer structure of a porous layer, a homogeneous layer, and a porous layer sequentially from the innermost layer, and the inner diameter is 200 μm, and the innermost layer is 25 μm, 1 μm, and 30 μm, respectively.
It has a thickness of m and a chloroform transmission rate of 2 x 10
^-3 (cm ³ (STP) / cm ² / sec / cmHg) was used. An aqueous solution containing 100 ppb of chloroform as a volatile organic substance dissolved in water was added to the system.
The removal performance of water-dissolved chloroform was investigated by flowing water at a flow rate of 01 / min and placing activated carbon at the position in front of the water-dissolved organic matter removal module and at the back of the module for long-term water passage. The results are shown in Table 1.

[0018]

[Table 1]

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a system of the present invention.

[Explanation of symbols]

 1 Aqueous Solution Inlet 2 Adsorbent 3 Water Volatile Organic Matter Removal Device 4 Hollow Fiber Membrane Module 5 Drinking Port 6 Water Dissolved Organic Matter Removal Module 7 Pressure Reducer (Intake Blower)

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] August 23, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

[0017]

EXAMPLES The present invention will be specifically described below based on examples. Example 1 A system shown in FIG. 1 was created. The composite hollow fiber membrane for removing dissolved organic matter in water has a three-layer structure of a porous layer, a homogeneous layer, and a porous layer in order from the innermost layer, and the inner diameter is 200 μm, and the innermost layer is 25 μm, 1 μm, and 30 μm, respectively.
It has a thickness of m and a chloroform transmission rate of 2 x 10
^-3 <br/> in Soraitomaku in ^{(cm 3 (STP) / cm} 2 / sec / cmHg) was used. An aqueous solution containing 100 ppb of chloroform as a volatile organic substance dissolved in water in the system,
The removal performance of the dissolved chloroform in water was investigated by flowing water at a flow rate of 1.0 l / min and placing activated carbon in front of the in-water dissolved organic matter removal module and passing it behind the activated water for a long time. The amount of activated carbon used at this time was 50 g.
It was. The results are shown in Table 1.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location // C02F 1/44 B 8014-4D

Claims (4)

[Claims] 1. After the adsorbent of chlorine and high molecular weight organic matter,
A partition wall that separates a container, a hollow fiber membrane located in the container, an end portion of the hollow fiber membrane, and a space communicating with the hollow portion of the hollow fiber membrane and a space communicating with the outer surface of the hollow fiber membrane. Has and
An inlet and an outlet for flowing an aqueous solution containing a volatile dissolved organic substance into a space formed by the outer surface of the hollow fiber membrane and the inner wall surface of the container, or an exhaust port for exhausting gas in the space and the space An intake port for taking in air outside the container, an exhaust port for exhausting gas into the hollow portion of the hollow fiber membrane, and an intake port for taking in air outside the container or an aqueous solution containing a volatile organic substance into the hollow portion. A system for removing dissolved organic matter in water, comprising a module for removing dissolved organic matter in water provided with an inlet and an outlet, and a filter for removing fine particles in water. 2. The removal system according to claim 1, wherein the organic substance dissolved in the aqueous solution is a volatile organic halogen substance. 3. The removal system according to claim 1, wherein the adsorbent for chlorine and the high molecular weight organic matter is activated carbon. 4. The removal system according to claim 1, wherein the filter for removing fine particles in water is a hollow fiber membrane.