JP2002336661A - Method for cleaning separation membrane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a treating technique to concentrate the un-adsorbed dyestuff-containing liquid waste generated at the final dyeing step by using a separation membrane, to recover the separated water and to reuse the recovered water. SOLUTION: This separation membrane cleaning method comprises a step to separate a spent solvent generated at the final fiber dyeing step into a spent fiber treating chemical and a solvent and regenerate the separated solvent by using the separation membrane. The spent solvent containing at least the precipitating component of the fiber treating chemical having 0.01-100 μm particle size is separated and regenerated to obtain a regenerated solvent. In this are thud, the solvent is separated and regenerated and the element of the separation membrane is cleaned by fluidizing the spent solvent on the surface layer of the separation membrane to the gravitating direction in a condition on of Fc/Fp>1 (wherein Fc is the flow rate of the concentrated liquid of the spent fiber treating chemical; Fp is the flow rate of the solvent to be regenerated).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning a separation membrane used in a step of regenerating a solvent from a solvent containing a used fiber treating agent generated in a fiber dyeing and finishing treatment step.

[0002]

2. Description of the Related Art Conventionally, in dyeing and finishing fibers, a large amount of water has been used and a large amount of water has been drained at the same time. The use of such a large amount of water has prospered in the processing cost of the dyeing finishing process, and the use of groundwater has problems such as land subsidence and environmental destruction.

[0003] Wastewater discharged in a large amount in the dyeing and finishing treatment contains various chemicals such as oils, textile wastes, dyes and the like, and the wastewater treatment imposes a great load. In addition, in recent years, regulations on wastewater have been strengthened year by year, and more effective wastewater treatment methods and wastewater reduction technologies are desired.

[0004] As a method of wastewater treatment, wastewater discharged in each step is collected at one place and subjected to various methods such as coagulation sedimentation method, activated sludge method, ion adsorption method, oxidation treatment method, neutralization method, activated carbon treatment and filtration treatment. The methods are used individually or in combination, and are treated collectively so as to reach the standard water quality, and then discharged to rivers and sewers.

On the other hand, the wastewater from the fiber dyeing and finishing plant is more processed than the papermaking industry, which uses a large amount of water.
The drainage components vary greatly depending on the processing content, and the temporal and temporal fluctuations are also large, making the wastewater treatment more difficult and difficult.

[0006] In particular, the dyeing process occupies a large part of the amount of wastewater in a dyeing finishing factory, and since it is a colored wastewater containing a large amount of unadsorbed dye, it is necessary to perform a more advanced wastewater treatment. is there.

As means for reducing the amount of wastewater in the dyeing process,
A low bath ratio type dyeing machine has been developed that can dye more fibers with less water.However, although the amount of wastewater discharged by dyeing can be reduced, unadsorbed dyes have a high concentration. In addition, the fiber is highly contaminated and requires a large amount of water in the subsequent washing process.

[0008] Therefore, the dyeing residue containing a large amount of unadsorbed dye is concentrated, recovered, and reused by the separation membrane using a separation membrane, so that colored wastewater containing dye discharged from the factory is reduced. Technology is being developed to significantly reduce wastewater by collecting and reusing water. However, some dyes are adsorbed on the separation membrane or settle on the surface of the separation membrane, causing deterioration of the performance of the separation membrane, and expediting replacement of expensive separation membranes, resulting in an increase in cost. Means for recovering the performance by washing the separation membrane are generally performed.However, the separation membrane that has been subjected to a long-term regeneration treatment with a high-concentration dye concentrate, or the dye is not sufficiently washed on the membrane surface due to insufficient washing. If stored for a long period of time, the dye will settle out on the surface layer of the separation membrane and form a layer. Large amounts of water and cleaning agents are required to completely remove such dyes and restore performance.

[0009] Further, depending on the type of separation membrane, backwashing cannot be performed depending on the type of separation membrane. Therefore, chemical cleaning with chemicals is used. However, since commercially available separation membranes reduce their performance when used in a high temperature region, Cleaning in a low temperature range is essential, and the cleaning effect with chemicals is insufficient.

[0010]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the processing technology of concentrating dye wastewater containing unadsorbed dyes generated during the dyeing finishing process using a separation membrane, and recovering and reusing water. Reduces sedimentation and accumulation of unadsorbed dye on the surface of the separation membrane while reducing the amount of water and wastewater used for washing, thus achieving a high cleaning effect and extending the replacement time of the separation membrane. And a method for cleaning the separation membrane.

[0011]

The present invention employs the following means in order to solve the above problems.
(1) Separation of a used solvent generated in a fiber dyeing / finishing step performed by dissolving and / or dispersing a fiber treating agent in a solvent into a used fiber treating agent and a solvent using a separation membrane. And, in the step of regenerating the solvent, at least the particle diameter of the fiber treatment agent is 0.01 to 100 μm
When separating and regenerating the used solvent containing the sedimentation component, the used solvent on the surface of the separation membrane flows in the direction of gravitational force when obtaining the regenerated solvent, and for the used fiber treatment obtained by the separation and regenerating process. A method for cleaning a separation membrane, comprising: separating a solvent, performing a regeneration treatment, and cleaning a separation membrane element when a flow rate of a concentrate of a drug (Fc) and a flow rate of a regeneration solvent (Fp) are Fc / Fp> 1.

(2) As the washing liquid for the separation membrane, a regenerated solvent obtained by separating and regenerating a used solvent or a new solvent used in the same dyeing and finishing step is used. Method for cleaning the separation membrane.

(3) As the washing liquid for the separation membrane, at least one selected from the group consisting of acids, alkalis, chelating agents, surfactants, preservatives, oxidizing agents and reducing agents is used by dissolving and / or dispersing it. The method for cleaning a separation membrane according to (2), wherein:

(4) The above (1) to (1), wherein the solvent regeneration treatment uses at least membrane separation.
The method for washing a separation membrane according to any of (3).

(5) The method according to any one of (1) to (4), wherein the separation membrane is at least one selected from an ultrafiltration membrane, a nanofiltration membrane, and a reverse osmosis membrane. How to wash the separation membrane.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention has been made to solve the above-mentioned problems, that is, to reduce the amount of water used for washing the separation membrane and the amount of waste water, while reducing the sedimentation and accumulation of unadsorbed dye on the surface of the separation membrane. Investigating the treatment method to extend the exchange time of the solvent, paying attention to the dye particle diameter and the sedimentation component contained in the used solvent, the used solvent flows on the surface of the separation membrane in the direction of gravity, and the separation and regeneration Solves unexpected problems at a glance by separating and regenerating the solvent at a flow rate (Fc) and a regenerating solvent flow rate (Fp) of the used fiber treating agent obtained by the treatment of Fc / Fp> 1. It is what we have determined to do.

The used solvent in the present invention is a solvent discharged by the fiber dyeing and finishing, and is used in the processes such as desizing, scouring, bleaching, mercerizing, weight loss, dyeing, printing, washing and finishing. Solvent remaining after the fiber processing is completed, in which various substances related to the processing steps such as fiber processing chemicals, fiber scraps, fiber decomposed products, and materials removed from the fibers are dissolved, dispersed or mixed. It is intended for. Liquids are mainly used as such solvents, and water, dimethylformamide, dimethylsulfoxide, methyl chloride, toluene, terpenes, alcohols and the like are used alone or in combination, but are not limited to these liquids. However, any solvent that is used as a main component of the treatment liquid for the fiber dyeing finishing treatment can be used in the present invention.

In the present invention, the used solvent is regenerated to obtain a regenerated solvent. The regenerated solvent used in the present invention is to separate these substances from the solvent mixed with various substances. That means. Substances to be separated are various, for example, various dyes or pigments, various ionic surfactants, natural, semi-synthetic, synthetic polymers called sizing agents, sodium sulfate, inorganic salts such as sodium carbonate, sulfuric acid, Examples include acids such as acetic acid, alkalis such as sodium hydroxide, oils, oxidizing agents, reducing agents, and the like, and also include decomposition products and aggregates thereof. In addition, fiber waste,
What also contains a fiber melt etc. is also included.

As described above, the composition of the used solvent is very complicated, and the composition greatly changes depending on the target fiber material and processing. Furthermore, there are many fluctuations in seasonal differences, monthly differences, and day-to-day differences, and it is difficult to efficiently separate them. Therefore, preferably, the used solvent generated in the dyeing and finishing step and the regenerated solvent are the same dye. It is good to use in the finishing process. The drugs used are then similar and less susceptible to residues. More preferably, they are used in the same dyeing and finishing apparatus. If the same apparatus is used, the history of the used fiber dyeing finishing chemicals becomes clear, and efficient separation is possible.

In the present invention, the particle diameter is at least 0.01.
The effect of the invention is great for a used solvent containing a precipitated component of 100 μm. The particle size in the present invention is generally the size of particles in a dispersion system containing colloidal particles or coarse particles, and usually represents the size of particles assuming that the shape of the dispersed particles is spherical. Further, sedimentation means that the fine particles contained in the used solvent are subjected to the action of gravity, and the concentration increases from the upper part to the lower part. Since the sedimentation velocity of the particles is proportional to the square of the particle radius, the particle diameter is 0.01 μm.
Since the particles having a particle size of less than 10 are relatively slow in sedimentation speed and are relatively easily removed by washing or the like before sedimentation on the surface of the separation membrane, the effect of the present invention is small. If the particle size exceeds 100 μm, it can be easily removed by a method such as using a simple filter such as a filter cloth in pretreatment.

Typical settling components contained in the used solvent generated in the dyeing and finishing step include disperse dyes, but are not particularly limited. Examples thereof include direct dyes, vat dyes, sulfur dyes, basic dyes, and naphthol. Dyes, acid dyes, acid mordant dyes, mordant dyes, oil-soluble dyes, reactive dyes, fluorescent bleaching agents, various dyes such as oxidation dyes, or antistatic agents, hand adjusters, flame retardants, water repellents, oil repellents, Various kinds of resin processing agents used for imparting functionality such as an antibacterial agent and a cross-linking agent can be used in the present invention as long as they are used solvents containing sedimentation components due to decomposition or aggregation due to heat or physical action.

FIG. 1 is a schematic view showing an example of the method for cleaning a separation membrane of the present invention. The used solvent flows through the surface of the separation membrane 1 in the direction of gravitational force to separate and regenerate the solvent;
In addition, the flow rate (Fc) of the concentrate of the used fiber treating agent and the flow rate of the regenerating solvent (Fp) obtained by the separation and the regenerating treatment are represented by Fc
By setting / Fp> 1, the settled component 2 contained in the used solvent can be settled preferentially in the downstream direction, which is the direction of flow and the direction of gravity. The particle sedimentation at the time of stoppage is not at the surface of the membrane but at the downstream side in the direction of gravitational force. on the other hand,
In the case of Fc / Fp <1, the flow rate to the regenerating solvent side increases, so that the fine particles mainly flow toward the film surface, and the particles tend to accumulate on the film surface.

FIG. 2 schematically shows a case where the used solvent flows on the surface of the separation membrane in the direction perpendicular to the direction of gravity for comparison. In this case, particles easily accumulate on the film surface due to the action of gravity. Further, even when Fc / Fp> 1, it is difficult to suppress particle sedimentation. Further, it has been found that in the configuration of the present invention, even when the separation membrane is washed, the settling component settled in the downstream portion can be efficiently removed by flowing the washing liquid from the upstream portion to the downstream portion.

As the washing liquid, it is preferable to use the same solvent used in the separation and regeneration treatment of the used solvent or in the dyeing and finishing step. More preferably, by using a regeneration solvent, the washing solution after washing is also collected,
Separation and regeneration are possible, so that the amount of wastewater can be further reduced, and if the same solvent is used, there is no danger of at least adverse effects such as poor dissolution of sedimentation components. It can be used in dyeing finishing processes and equipment.

As a cleaning method, the method of dipping in a cleaning solution for a long period of time or circulating the cleaning solution over the surface of the separation membrane is highly effective. By vibrating the membrane element itself or using one or several kinds of ultrasonic vibrations, it is possible to obtain a high washing effect on the sedimentation component. More preferably, the combined use of various chemicals re-disperses the sedimented component, thereby obtaining a high effect. Although there is no particular limitation on these agents, acids, alkalis, chelating agents, preservatives, oxidizing agents, reducing agents, various surfactants, and the like can be used in combination, and can be used as appropriate depending on the contents of the used solvent.

As the means for regenerating the used solvent, membrane separation is used, but existing techniques can be used alone or in combination. For example, coagulation sedimentation, activated sludge, ion adsorption, oxidation, Neutralization treatment, activated carbon treatment, filtration treatment, distillation and the like can be used. Various filtration treatments can be used for the membrane separation, but it is preferable to have a mechanism for regenerating the solvent using at least one selected from an ultrafiltration membrane, a nano separation membrane, and a reverse osmosis membrane.

The fibers referred to in the present invention are not particularly limited. Examples of the material include plant fibers such as cotton and hemp, animal fibers such as wool and silk, regenerated fibers such as rayon, and semi-synthetic materials such as acetate. Fibers, synthetic fibers such as polyamide, polyester, and acrylic can be used. As the structure composed of such fibers, yarn, woven fabric, knitted fabric, non-woven fabric, garment and the like can be used.

[0028]

The present invention will be described in more detail with reference to the following examples. The physical properties and the like described in the examples were determined by the following methods.

Absorbance measurement: UV-3 manufactured by Shimadzu Corporation
A 100 spectrophotometer was used.

Electric conductivity: An electric conductivity meter AB-7 manufactured by Organo Co., Ltd. was used.

The flow rate of the concentrated solution (Fc) and the flow rate of the regenerated solvent (Fc)
Measurement method of p): The concentrated liquid flow rate (Fc) is measured with a flow meter provided at the outlet of the concentrated liquid. (Instantaneous flow rate type: IR-4000-1P) The regenerated solvent flow rate (Fp) is measured by a flow meter provided at the regenerated solvent outlet. (Instant flow rate type; IR-4000-1P) [Example 1] Dyeing was performed under the following conditions.

Material 100% polyester taffeta device Liquid jet dyeing machine (500VPH-RL-1: manufactured by Nissen Co., Ltd.) Dyeing conditions Dyes and auxiliaries: Dianix Tuxedo Black F conc: 20% owf Ionnet RAP-250: 1.5 g / L PH500 (pH adjuster): 1.0 g / l Temperature: 130 ° C x 30 minutes Liquid volume: 1000 L Bath ratio: 1:10 The wastewater after dyeing was collected and regenerated under the following conditions.

[0033] Regeneration treatment of dyeing water was performed in a treatment facility provided with a reverse osmosis membrane element so that the dyeing wastewater flows in the direction of gravity. The flow rate of the regenerated water (= regenerated solvent flow rate (Fp)) regenerated from the reverse osmosis membrane immediately after the start of the regenerating treatment is 21 L / min, the flow rate of the concentrated water (= concentrated fluid flow rate (Fc)) is 63 L / min, and the dyeing wastewater is discharged. At the time of concentration to 50L, the flow rate of regenerated water is 13L
/ Min, and the flow rate of the concentrated water was 63 L / min. After taking out the concentrated dye wastewater, 100 L of regenerated water was circulated from the upstream part to the downstream part and washed for 10 minutes. The reclaimed water used for washing was drained, and fresh reclaimed water was filled in the apparatus and stored for 4 hours. This treatment was carried out 6 times a day, every day, and the flow rate of the regenerated water regenerated from the reverse osmosis membrane one month later was measured. The flow rate of the regenerated water was 20 L / min and the flow rate of the concentrated water was 63 L immediately after the start of the regeneration treatment. The flow rate of the regenerated water at the time of concentration to 50 L / min was 13 L / min, and the flow rate of the concentrated water was 63 L / min. There was no performance degradation. Table 1 shows the results.

[Comparative Example 1] The same dyeing as in the example was performed in a treatment facility provided with a reverse osmosis membrane element so that the dyeing wastewater flowed horizontally, and the wastewater after the dyeing was collected and regenerated. went. The flow rate of the regeneration water regenerated from the reverse osmosis membrane immediately after the start of the regeneration treatment is 20 L / min, and the flow rate of the concentrated water is 63 L / min.
When the dyeing wastewater was concentrated to 50 L, the flow rate of the regenerated water was 13 L / min, and the flow rate of the concentrated water was 63 L / min. After taking out the concentrated dye wastewater, 100 L of regenerated water was circulated and washed with water for 10 minutes. Then, the regenerated water was drained, and the apparatus was filled with new regenerated water and stored for 4 hours. This treatment was performed 6 times a day, every day, and the flow rate of the regenerated water regenerated from the reverse osmosis membrane one month later was measured. The flow rate of the regenerated water immediately after the start of the regeneration treatment was 12 L / min, and the flow rate of the concentrated water was 63 L / min.
The flow rate of the regenerated water at the time when the dyeing wastewater was concentrated to 50 L was reduced to 5 L / min, and the flow rate of the concentrated water was 63 L. . The electrical conductivity and transmittance of the regenerated water were not problematic. Table 1 shows the results.

[0035]

[Table 1]

[0036]

According to the present invention, when a separation membrane is used from the used solvent discharged in the dyeing step and the solvent is regenerated, the separation membrane elements are arranged vertically, and the separation membrane elements are arranged from upstream to downstream of the elements. The used solvent is supplied to the solvent, and the solvent is separated and regenerated.
The replacement time of the separation membrane can be extended while reducing the amount of water used and the amount of water used for washing the separation membrane while reducing deposition.

[Brief description of the drawings]

FIG. 1 is a schematic view showing one example of a method for cleaning a separation membrane of the present invention.

FIG. 2 is a schematic view illustrating a case where a used solvent for comparison flows on a surface layer of a separation membrane in a direction perpendicular to the direction of gravity.

[Explanation of symbols]

 1: Separation membrane 2: Settling component

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) C02F 1/44 ZAB C02F 1/44 ZABK F term (Reference) 4D006 GA03 GA06 GA07 KA01 KA31 KA72 KB11 KB12 KB13 KB14 KB18 KB22 KC13 KC14 KC16 KD01 KD02 KD03 KD04 KD11 KD17 KE02Q KE04Q MA22 PA01 PB08 PB14 PB22 PB25 PB26 PB34 PB59 PC80

Claims (5)

[Claims] 1. A method for separating a used fiber produced in a fiber dyeing and finishing step by dissolving and / or dispersing a fiber treating agent in a solvent into a used fiber treating agent and a solvent using a separation membrane. In the step of regenerating the solvent, at least the particle diameter of the fiber treating agent is 0.01 to 1
When separating and regenerating a used solvent containing a sedimented component of 00 μm and obtaining a regenerated solvent, the used solvent on the surface layer of the separation membrane flows in the direction of gravitational action, and the used fiber treatment obtained by the separation and regeneration processing A method for cleaning a separation membrane, comprising separating a solvent, performing a regeneration treatment, and cleaning a separation membrane element when a flow rate of a concentrate (Fc) and a flow rate of a regenerating solvent (Fp) of the chemical for use are Fc / Fp> 1. 2. The separation method according to claim 1, wherein a used solvent used in the same dyeing and finishing step is a regenerated solvent obtained by separating and regenerating a used solvent or a new solvent used in the same dyeing and finishing step. How to clean the membrane. 3. A method for dissolving and / or dispersing at least one selected from the group consisting of an acid, an alkali, a chelating agent, a surfactant, a preservative, an oxidizing agent and a reducing agent as a washing liquid for the separation membrane. 3. The method according to claim 2, wherein
3. The method for cleaning a separation membrane according to item 1. 4. The method for cleaning a separation membrane according to claim 1, wherein the solvent regeneration treatment uses at least membrane separation. 5. The washing of a separation membrane according to claim 1, wherein the separation membrane is at least one selected from an ultrafiltration membrane, a nanofiltration membrane, and a reverse osmosis membrane. Method.