JPH07503264A - How to remove dye - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] How to remove dye field of invention The present invention removes the dye from a dyeing solution comprising a dye and a salt to produce a purified salt. A method for enabling a solution to be reused or disposed of; and a method for carrying out this method. Regarding equipment.

Conventional technology According to conventional dyeing techniques, the fabric is treated with an active dye solution. the dye leaves the solution Salts are added to the dyeing solution in significant concentrations (e.g. (e.g., sodium sulfate or sodium chloride), typically a dye and the required color. It is usually included in an amount of 20 to 100 g/L depending on the depth of the mixture. It has become. The presence of salt effectively reduces the solubility of the dye in solution and Disturbs the equilibrium between the dye on the fabric and the dye on the fabric, promoting adsorption of the dye on the fabric. do. Typically, 80% of the dye in the dyeing solution is transferred onto the fabric. This 80 %, typically 70% reacts with the fabric and the remaining 10% of the dye remains unreacted. It remains the same. Currently, used dye solutions containing residual dyes and salts must be disposed of. Ru. However, disposing of used staining solutions in an environmentally acceptable manner is critical. force a problem.

In addition to salt, dye baths contain customary additives such as sequestrants, lubricants and alkalis. Vine.

The dyed fabric containing the reacted and unreacted dye is then washed several times with clean water. typical The first rinse is with cold water, followed by the second rinse at 60°C for 30-60 minutes. followed by a third rinse at 95°C followed by two more rinses at 160°C.

The exact order of washing steps used will vary depending on the type and concentration of dye used. higher concentrations generally require more washing steps.

A typical dyeing tank that can dye 250 kg of fabric has approximately 3,500 cubic feet of liquid. will hold. Therefore, the above volumes of used dye and salt solutions can be safely It will be necessary to dispose of it. In the 5-step cleaning process, 5 times the volume of diluted It also requires that the staining solution be safely disposed of. This poses a serious problem. There is.

It is an object of the present invention to alleviate these problems, and in particular to dyes containing dyes and salts. The object of the present invention is to provide a method for removing dye from a solution.

Summary of the invention The present invention provides a method for removing dye from a dyeing solution comprising a dye and a salt; The method is - contacting the dyeing solution with particles of activated carbon and adsorbing the dye onto the particles; do - remove these particles with the dye adsorbed onto them from the dyeing solution to reduce the dye concentration; creating a cleansing salt solution with a high concentration of water.

The invention also extends to corresponding devices.

Activated carbon is known to be useful in decolorizing aqueous liquids. But long However, the present invention surprisingly shows that the presence of salt in the dyeing solution does not affect the dyeing on activated carbon particles. Based on the discovery that it improves the adsorption of materials. Dye adsorption depends on the salt concentration of Ig/L. Although enhanced at lower concentrations, higher concentrations of 3°5 and log/L show particular enhancement.

Typically the stain bath contains 30-90 g/L salt (usually NaCl or Naps). o+) a On the other hand, the presence of salts has a detrimental effect on the adsorption of the dye onto another solid phase substrate. It was discovered that Dye removal can be achieved, for example, by the presence of NaOH or Na2COs. was also found to be improved at high pH.

This method is particularly applicable to reactive dyes, i.e. dyes that react with the material to be dyed. .

The activated carbon is generally a crude charcoal material without any additives. suitable grade is available under the trade name Celite. The weight of activated carbon used is generally 0.1 to 20 times (preferably 1 to 20 times, especially 2 to lo times) the amount of dye in the solution. ). The particle size of activated carbon particles is usually 0.1 to 200 microns (preferably 1 ~40 microns).

It was found that salts in the staining solution were not adsorbed to any significant extent by activated carbon. .

The carbon particles with the dye adsorbed thereon are then removed from the dyeing solution. this is, By forming activated carbon particles as a fixed layer and passing a dyeing solution through this. can be achieved. However, in a preferred embodiment, the carbon particles are freely dispersed in a liquid and then removed by e.g. filtration, sedimentation and centrifugation. Remove.

The type of filter used depends on the particle size of the activated carbon and therefore different filtration processes are possible. That would be appropriate. However, to provide a continuous process, cross-flow filtration technology Alternatively, back-pulse filtration techniques are advantageously employed.

In cross-flow filters, a dyeing solution with activated carbon particles dispersed therein the lumen of the fiber bundle with porous walls (e.g. porous expanded polyester) (tetrafluoroethylene). The cleaning salt solution (with reduced dye concentration) is through the fiber walls, while the carbon particles are retained in a concentrated stream of activated carbon particles. On top of that The activated carbon particles with adsorbed dye are then filtered from the concentrated solution to substantially A solid residue can be left behind, which can be removed by conventional means, such as ashing or landfilling. Can be safely disposed of. The cleaned salt solution can be reused.

Back-pulse filtration typically involves passing the dye solution and dispersed carbon particles through a candle filtration process. The solution is passed from the outside of the filter to the inside. pass Candle filters are known in the industry and this It is closed at the top and is open at the upper end (exit), and is connected to the frame. It comprises a hollow sleeve of filter fabric which is fixed thereto. Its open end is the filtrate It leads to a plenum chamber for receiving. Especially useful filter cloth The fabric is porous PTFE laminated to a fiberglass or polyester support material. (available under the trade name Gore-teX). The carbon is filtered and and deposits on the outside of the candle filter. Periodically, backflow the liquid flow. Invert the filter using a lugs to peel off any accumulated filter cake. This is at the bottom of the filter tank Sediment.

This solid filter cake is then removed, for example by a screw conveyor. Ru.

Depending on the residual concentration of dye in the cleaning salt solution, this solution will remove unreacted dye from the fabric. can be used in some or all of the subsequent washing steps to remove for example, A clean salt solution can be used to rinse dyed fabrics. Used salt rinse The solution consists of the addition of activated carbon to adsorb the dye, followed by the removal of the activated carbon particles. cleaner and recycle the cleaned rinse salt solution to the rinse tank.

This allows rinsing and dye removal to be carried out in a virtually continuous manner, allowing for The amount of rinsing solution used can be substantially reduced and the rinsing operation can be sped up.

A final rinse before drying the fabric can be performed using pure, unsalted water. This is Similar cleaning methods in which adhesives are added and then removed from the water before subjecting the purified water to recycling. By using carbon or other solid adsorbents in the water rinse cycle It can be achieved.

This method saves time and thermal energy, and also reduces the amount of water used. and saves salt. Adsorption of dyes onto activated carbon poses a large volume of effluent disposal problem. Substantial mitigation.

Detailed description of preferred aspects Embodiments of the present invention will be described by way of example only with reference to the drawings. Figure 1 is a general flowchart of the method according to the invention; Figure 2 shows the flow diagram of the method according to the invention; The variation in dye removal is shown; FIG. 3 shows the cross-flow filtration device for Example 7.

FIG. 1 shows a dyeing bath B containing a roll of fabric 2 to be dyed. This tank contains reactive dyes and Contains a solution of water and salt. Staining is typically performed at 95°C. After staining is completed, The spent dye/salt solution is removed from the tank along line 4 and transferred to tank T. collect. In this tank, activated carbon C is introduced into the spent dye/salt solution. and the mixture is subjected to agitation until the dye is adsorbed onto the activated carbon particles. It will be done. The liquid is then circulated from tank T along line 6 by circulation pump P. Pump into Souflow Filter F. This cross-flow filter F is Porous materials, such as polytetrafluoroethylene (PTFE), polypropylene or a bundle of hollow fibers made of polysulfone. Its pore size is usually 0.1 In the range of ~2 microns. A dye containing carbon particles having an adsorbed dye thereon /The flow of salt solution passes through the lumen of this fiber. Reduced (or preferred) dye concentration or 0) The cleaned salt solution stream passes through the walls of this fiber and then cleans along line 8. loss-flow filter and returned for use in stain bath B. (or stored for future staining operations). The returned purified salt solution is dyed cloth. It is used in tank B for further rinsing operations on the soil.

A concentrated stream containing carbon particles having dye thereon is passed from filter F to line 10. It exits along the road and returns to tank T. A portion of this recycling will be sent along Line 12. diverted from line IO to D, where spent activated carbon with adsorbed dye be removed and discarded. On the other hand, at the end of the dyeing operation, this flow is It may be further concentrated by passing it through the filter repeatedly.

If desired, the fabric may be rinsed with clean, unsalted water, optionally carbon or unsalted. Can be subjected to a similar rinse cycle using another solid adsorbent active in water . The salt solution is replaced by clean water, and if desired the carbon is replaced with fresh adsorbent. May be replaced. On the other hand, a second dedicated clean water rinsing circuit (further tank T, pump (including filter P and filter F) may be provided in addition to the illustrated salt solution circuit.

The presence of salt in the dye solution enhances the adsorption of the dye onto the activated carbon. This is the example below. This will be demonstrated in

Example l (comparison) Type Procion Yellow 1 (E4R reactive dye solution in 80℃ hot water) 1 g of dye/water was prepared at once.

Weigh out 150ml of this solution (0.15g of dye) into a beaker, and add 2g of Activated carbon type Celite 2850 (NW) was added. This is about 65 weight % had a particle size less than 45 microns and the remainder was greater than 40 microns. . The mixture was mechanically stirred for 5 minutes and then passed through a Buchner wax through a number 5 filter paper. Filtered onto a doo. with a sample of Procion Yellow HE4R of known concentration. By colorimetry, the dye concentration in the solution was determined to be approximately 0.5 g/liter.

Example 2 The procedure of Example 1 was repeated, except that this dye solution resembled a common salt/dye containing solution. An additional 5 g/L of sodium chloride (analytical grade) was included to increase the concentration. Before and Add 2 g of activated carbon in the same way and stir for 5 minutes before filtering the mixture. I kept it. The filtrate contained no visible dye by visual evaluation.

Therefore, the presence of salt in the reactive dye solution causes the particulate active particles to remove the dye from the dyeing solution. It can be thought of as increasing the ability to adsorb. This is especially true for dyeing cotton and cotton-containing fabrics. It has uses in

Example 3 Further tests were carried out using the same type of activated carbon adsorbent and salt as in Examples 1 and 2. . Identical experimental procedures were performed except for dye combinations, dye concentrations, salt concentrations, pt+ and dye:adsorbent weight ratios were tested.

A salt concentration of zero was included for comparison.

The color of each filtrate from each combination was visually evaluated as in Examples 1 and 2. Exam details Table 1 shows the color and color of the resulting filtrate.

Money 14 (Yui Yui's 11 D6111 fishing ^1 1),,1. ``DDl + Tsul notepu I → main ζ l - 壬 1t Yixiao Feng. ■Puha White 1S, GaraijT7'l-11-Go (懺111 11jL V) Using the procedure of Kumenino Example 1, perform further experiments at various salt concentrations. did. The dye was Procion Navy (IER150).

The results are shown in Tables 2 and 3 and graphed in Figure 2, which is 0.3 and Residual dye concentration as a function of salt concentration at a dye:carbon adsorbent ratio of 0.15 Show variation.

1 1 0.3 7 0.93 I〆〆　　　　　　　　0.45 //40//l1O939 + 1 0.15 7 0.40 For two types of dyes, at various pHs (NaO)1 or Na2CO3 addition Further tests were carried out at

The results for Procion Navy HER150 are in Table 4 and the removal was It was proven.

Procion Red HEGXL 1.092kg” Red HEXL 0.72kg Total liquid capacity = 1750L Fabric weight = 207.8kg (a) To simulate low salt levels, add 270n+1 water to the effluent 3 above. Added to 0ml. Activated carbon powder Ce1ite Z850 (0,0,16g) and stirred for 5 minutes.

300 ml of this was filtered as in the previous example.

(b) This procedure was repeated, but to maintain approximately the original salt concentration. Salt was added to 300 ml of solution at a concentration of 45 g/L.

The results showed that the filtrate from the salt addition test was approximately half the tonal density of that without salt addition. It showed that there is. Therefore, the bell in case (b) was doubled.

Example 7 (cross flow filtration) Reactive dyes from dye bath effluent using carbon adsorption followed by cross-flow filtration The following tests were conducted to perform the removal.

A sample of the vat contents was removed from the vat at the end of the staining.

The contents of the dye tank are as follows: Dyelube NF 1.75L Drimagen ER1,75L Salt (NaCI) 45 g/L Soda ash 15g/L Procion Yellow IIE4R28gI/Red IIEGXL 1.092kgノ’RedHEXL0.72kg Water capacity = 1750L Fabric weight = 207.8kg Place 8 liters of dye bath liquid sample into the pilot plant tank shown in Figure 3. Ta.

I closed the valve V□ before pouring this 8 liters of liquid into the tank. . 37g activated carbon powder type Celite z850 (CeliteNW) was added to the tank. The contents of this tank were drained using a low shear hand-held Starsea for 5 minutes. Stirred.

Then valve V1 is opened and valves V+', V+ and V. I kept it closed.

Turn on pump P, open Vl and Vo, P, = 2 bar, po = 1.5 bar, P = 1.5 bar.

Then, the valve ■ was opened and the filtrate was collected (PP = o). The flow rate of the filtrate is 0. It was measured at 5 liters per minute.

The temperature was about 20°C. The bundle of tubes each has an outer diameter of 6 mm and an inner diameter of 4 mm. It consists of 10 membrane tubes with a length of 0.5 meters, 0,062 m2 filtration area is provided.

The tube was a Gore-Tex™ expanded porous PTFE tubular membrane. messenger The isopropanol bubble point of the tubular membrane used was 3 psi (EP01064 (See No. 94).

The filtrate was colorless, indicating that virtually all dye had been removed.

The linear velocity of the filtrate was 484 (liter/m2 hours).

The dye concentration was 1.05 g/L at the start of dyeing. Exclusion of dye during dyeing Based on this, approximately 30% of the dye remained in the liquid and the remaining 70% was retained on the brocade. Will. Therefore, approximately 0.1315 g/L of dye remains in the solution at the end of dyeing. It was. Therefore, the dye:adsorbent ratio was approximately 0.068.

one

Claims (16)

[Claims] 1. A method for removing dye from a dyeing solution comprising a dye and a salt, the method comprising: - contacting the dyeing solution with particles of activated carbon and adsorbing the dye onto the particles; do - remove these particles with the dye adsorbed onto them from the dyeing solution to reduce the dye concentration; creating a cleansing salt solution with a high concentration of water. 2. 2. The dyeing solution according to claim 1, wherein the salt concentration in the dyeing solution is at least 1 g/liter. the method of. 3. 2. The dye solution according to claim 1, wherein the salt concentration in the dyeing solution is at least 3 g/liter. the method of. 4. 2. The dyeing solution according to claim 1, wherein the salt concentration in the dyeing solution is at least 5 g/liter. the method of. 5. Claim 1, wherein the salt concentration in the dyeing solution is at least 10 g/liter. How to put it on. 6. Any one of the preceding claims, wherein said dyeing solution has an alkaline pH. The method described in section. 7. of the preceding claim, wherein said salt is selected from sodium chloride and sodium sulfate. Any method described in item 1. 8. The weight of activated carbon used is 1 to 20 times the weight of the dye in the solution. A method according to any one of the claims. 9. 9. The method according to claim 8, wherein the weight of the activated carbon used is 2 to 10 times the weight of the dye. Method. 10. Any one of the preceding claims, wherein the particle size of the activated carbon is between 1 and 40 microns. The method described in section. 11. Any of the preceding claims, wherein the particles are removed from the dyeing solution by filtration. or the method described in paragraph 1. 12. The filtration comprises passing the dyeing solution and carbon particles through the lumen of a bundle of porous hollow fibers; and carried out by cross-flow filtration, passing the purified solution through its fiber walls. 12. The method of claim 11. 13. the porous hollow fiber is made of expanded polytetrafluoroethylene; 13. The method according to claim 12. 14. The filtration is carried out in a batter pulsed liquid filtration device comprising a liquid filtration membrane. 12. The method according to claim 11, wherein the method comprises: 15. The liquid filtration membrane is a porous polytetrafluoroethylene layered on a support fabric. 15. The method of claim 14, comprising a tyrene film. 16. Utilization of activated carbon particles for the removal of dyes from salt-containing dyeing solutions.