Methods and systems for decolorizing textile materials

Abstract

Provided herein is a method for decolorizing textile materials under hydrothermal conditions using dye adsorbent materials. The process is non-toxic and environmentally friendly, and the adsorbent materials can be repeatedly used. The textile materials are textile materials dyeable with disperse dyes. Further provided is a system for decolorizing textile materials. The decolorization system is designed to allow the adsorbent materials to react with the textile materials in a contact manner and a non-contact manner.

Claims

1. A decolorization system for decolorizing textile materials, comprising: a decolorization reactor (1) for treating the textile materials under hydrothermal conditions so as to at least partially decolorize the textile materials, wherein the decolorization reactor is provided with a feed inlet (11) and an outlet (12) and is configured to accommodate water, the textile materials and optional dye adsorbent materials; a heating device (2) for providing a heat source to the decolorization reactor; a filtration device (3) for filtering and collecting the at least partially decolorized textile materials, wherein the filtration device (3) is connected to the outlet (12) of the decolorization reactor (1) via a first valve (4), wherein: (i) in the case where the decolorization reactor (1) is configured to accommodate water, the textile materials and the dye adsorbent materials, the decolorization further comprises: a separation device (7) for separating and collecting the dye adsorbent materials; or (ii) in the case where the decolorization reactor (1) is configured to accommodate water and the textile material, the decolorization system further comprises: an adsorption device (31) configured to accommodate the dye adsorbent materials, wherein the adsorption device (31) is in fluid communication with the decolorization reactor (1) so as to receive a liquid containing dye molecules desorbed from the textile materials collected from the decolorization reactor (1), and to allow the dye adsorbent materials to contact with the liquid.

2. The decolorization system according to claim 1 further comprising: a stirring device (8) for promoting the dye molecules within the textile materials being separated from the textile materials and dispersed into water, wherein the stirring device (8) comprises a stirrer (5) and optionally an ultrasonic probe (6).

3. The decolorization system according to claim 1, wherein the separation device (7) is disposed outside the decolorization reactor (1) and comprises at least one magnetic field generator, and the dye adsorbent materials are magnetized dye adsorbent materials.

4. The decolorization system according to claim 1, wherein: the adsorption device (31) is disposed in a circulation loop that is in fluid communication with the decolorization reactor (1), and the circulation loop further comprises a liquid collector (21) and at least one circulation pump (22, 32), wherein the liquid collector (21), the at least one circulation pump (22, 32) and the adsorption device (31) are in fluid communication.

5. The decolorization system according to claim 4, wherein: the circulation loop comprises a first circulation loop (20) and a second circulation loop (30), wherein, the first circulation loop (20) comprises the liquid collector (21) and a first circulation pump (22), and the first circulation loop (20) is in fluid communication with the decolorization reactor (1); and the second circulation loop (30) comprises the adsorption device (31), a second circulation pump (32) and optionally an observation hole (33), and the second circulation loop (30) is in fluid communication with the liquid collector (21).

6. The decolorization system according to claim 1, wherein the adsorption device (31) comprises at least one adsorption column (34), and a second valve (35) and a third valve (36) connected to both ends of the adsorption column (34), wherein the adsorption column (34) is configured to accommodate the dye adsorbent materials.

7. The decolorization system according to claim 1, wherein the heating device (2) is one of a steam heating device, an electric heating device, a microwave heating device or any combination thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above objects and features as well as other objects and features of the present disclosure will become apparent from the following description of the present invention in conjunction with the accompanying drawings, wherein:

(2) FIG. 1 is a schematic diagram showing a contact type decolorization system according to certain embodiments of the present disclosure;

(3) FIG. 2 is a schematic diagram showing a non-contact type decolorization system according to certain embodiments of the present disclosure;

(4) FIG. 3 shows the photos of the pieces of the textile materials before and after decolorization by activated carbon according to an example of the present disclosure;

(5) FIG. 4 shows a graph showing the K/S value of textile cloths against the number of repeated use of the activated carbon particles;

(6) FIG. 5 shows the photos of PS beads before and after decolorization, and photos of polyester cloths before and after decolorization; and

(7) FIG. 6 shows a typical magnetization-magnetic field (M-H) curve of magnetic activated carbon particles.

DETAILED DESCRIPTION

(8) The scope of the present disclosure is not limited to any specific embodiment described herein. The following embodiments are provided only for illustration.

(9) As shown in FIG. 1, during the process of decolorization treatment in the contact type decolorization system, textile cloths, magnetic adsorbent materials and deionized water are added in a certain ratio into the decolorization reactor (1) via feed inlet (11), and the stirrer (5) is started at the same time to stir the mixture. Under autogenic pressure, the materials in the decolorization reactor (1) are heated to about 100° C. to 170° C. by the heating device (2). Optionally, the ultrasonic generator (9) is started to drive the ultrasonic probe (6), thereby accelerating dispersion of the dye molecules from the textile materials into the water. During decolorizing reaction, the temperature detector (13) and pressure detector (14) may be used to respectively detect the temperature and pressure during the reaction. After reaction, the magnetic field generator (7) is started to generate magnetic field, so as to separate the magnetic dye adsorbent materials from the textile materials. The magnetic adsorbent materials are collected, cleaned and dried, and they may be reused in the decolorizing method according to the present invention until saturation and no decolorizing effect is achieved. The textile materials enter into the filtration device (3) via outlet (12) and the first valve (4) after decolorization. After filtration, the decolorized textile materials are collected and dried for further applications.

(10) As shown in FIG. 2, during the process of decolorization treatment in the non-contact type decolorization system, dye adsorbent materials are loaded into the adsorption column (34), and textile pieces and deionized water is added in a certain ratio into the decolorization reactor (1) via feed inlet (11). The stirrer (5) is started at the same time to stir the mixture. Under autogenic pressure, the materials in the decolorization reactor (1) are heated to about 100° C. to 170° C. by the heating device (2). Optionally, the ultrasonic generator (9) is started to drive the ultrasonic probe (6), thereby accelerating dispersion of the dye molecules from the textile materials into water. During decolorizing reaction, the temperature detector (13) and pressure detector (14) may be used to respectively detect the temperature and pressure during the reaction. Liquid containing dye molecules desorbed from the textile pieces in the decolorization reactor (1) flow through the first circulation loop (20) and second circulation loop (30) via outlet (12), and pass through the adsorption column (34). The adsorption column (34) can adsorb dye molecules from the liquid passed through. The liquid processed by the adsorption column (34) flows back into the liquid collector (21) through the piping, and then into the decolorization reactor (1). Under the action of circulation pumps (22, 32), the mixture of dye molecules dispersed in the water is able to circulate through the piping. During this period, the color of the water may be observed through the observation hole (32), and the degree of saturation of the adsorbent materials is thereby judged. After decolorization, the decolorized textile materials enter into the filtration device (3) via the outlet (12) and the first valve (4). After filtration, the decolorized textile materials are collected and dried for further applications. The used water and the dye adsorbent materials in the adsorption column can be reused until the dye adsorbent materials are saturated and no decolorizing effect is achieved. When the dye adsorbent materials are saturated and no decolorizing effect is achieved, the adsorption column may be replaced so as to proceed with the decolorizing process.

(11) Compared with the existing methods and systems, the decolorizing method and/or the decolorization system according to the present disclosure enable high dye removal rates and are able to remove the dye molecules from the textile materials more effectively in a shorter time period. Moreover, the color intensity of the decolorized textile materials is significantly reduced and residual dyes reduced. Meanwhile, since water is used as the decolorization solvent, and neither toxic and harmful chemical reagents nor acid and alkali organic solvents are used during decolorization, the decolorizing method and the decolorization system according to the present disclosure will not destroy the structural integrity of the textile materials, and are not harmful to the environment, which is beneficial to environment and human health. Therefore, the decolorizing method and/or the decolorization system according to the present disclosure are able to produce decolorized textile materials recoverable at a higher rate, and thus have greater application value in many aspects.

(12) Unless otherwise specified in the context, the term “comprise”, “include” or “contain” as used throughout the specification and claims should be construed as implicitly including the elements, components or features as recited, or a group of the elements, components or features, without excluding any other elements, components or features, or a group of the other elements, components or features.

(13) Unless otherwise defined, all the other technical terms used herein have the same meanings as those generally understood by those skilled in the art to which the present invention pertains.

Example 1. Decolorizing Textile Materials with Magnetic Activated Carbon in a Contact Type Decolorization System

(14) 2 g of magnetic activated carbon particles, 100 ml of deionized water and 2 g of textile piece were added into a 350 ml decolorization reactor of the contact type decolorization system as shown in FIG. 1. The mixture was steam heated to 130° C., 140° C. and 150° C., respectively, and stirred for 3 hours. After reaction, the magnetic field generator was started to adsorb and collect the magnetic activated carbon particles, and the textile materials were filtered, cleaned and dried.

(15) The color intensities (K/S values) of the textile materials were measured by an X-Rite UV/VIS spectrophotometer before and after decolorization; and percentage of color intensity reduction were calculated. Table 1 shows the K/S values of various textile materials before and after decolorization at different temperatures as well as decolorizing rates thereof.

(16) TABLE-US-00001 TABLE 1 the K/S values before and after decolorization at different temperatures and the percentage of color intensity reduction Treatment K/S values Color temperature before after reduction Textile materials (° C.) treatment treatment (%) Sample 1 (red knitted 130 9.66 0.50 95 cloth) Sample 2 5.40 0.34 94 (yellow knitted cloth) Sample 3 (red woven 140 22.71 1.56 93 cloth) Sample 4 1.21 0.12 90 (yellow woven cloth) Sample 5 (red woven 150 7.19 0.24 97 cloth) Sample 6 4.50 0.21 95 (yellow woven cloth)

(17) As can be seen from the experimental results, after decolorization, the color intensities of the textile materials were greatly reduced to very pale or even white, with the reduction of color intensity up to above 90%.

(18) In order to further demonstrate the reusability of the magnetic activated carbon particles during the decolorizing process, red woven cloths were decolorized as described above. The used magnetic activated carbon particles were reused in the decolorizing process multiple times, with the repetition number of greater than 10. The K/S values of the cloths were measured after each decolorization treatment. The K/S values of the textile materials against the number of repeated use of the magnetic activated carbon particles were plotted and shown in FIG. 4. As can be seen, the same magnetic activated carbon particles can be reused more than ten times without weakening the decolorizing effect.

Example 2. Decolorizing Textile Materials with Activated Carbon Particles in a Non-Contact Type Decolorization System

(19) 1 g of activated carbon particles, 100 ml of deionized water and 1 g of colored textile cloths were added into the adsorption column and the decolorization reactor of the non-contact type decolorization system as shown in FIG. 2, respectively. The decolorization reactor had a volume of 350 ml. The mixture was electrically heated to 150° C., and stirred and ultrasonic-processed for 4 hours. After reaction, the textile materials were taken out of the mixture, cleaned and dried.

(20) The color intensities (K/S values) of the textile materials before and after decolorization were measured by an X-Rite UV/VIS spectrophotometer; and the percentage of color intensity reduction were calculated. Table 2 shows the K/S values of various textile materials before and after decolorization, as well as color intensity reduction percentage thereof.

(21) TABLE-US-00002 TABLE 2 the K/S values before and after decolorization and the decolorizing rates Treatment K/S values Color temperature before after reduction Textile materials (° C.) treatment treatment (%) Sample 1 150 9.66 0.13 99 (red knitted cloth) Sample 2 4.50 0.12 97 (yellow woven cloth) Sample 3 10.28 0.14 99 (blue knitted cloth) Sample 4 (red woven 7.19 0.18 97 cloth) Sample 5 5.40 0.11 98 (yellow knitted cloth)

(22) FIG. 3 shows photos of some of the textile pieces before and after decolorization.

(23) As can be seen from the experimental results, after decolorization, the color intensities of the textile materials were greatly reduced to very pale or even white, with the reduction of color intensity up above 90%.

Example 3. Decolorize Polyester Cloths with Cross-Linked Polystyrene Beads in a Non-Contact Type Decolorization System

(24) 2 g of cross-linked polystyrene (PS) beads, 0.1 g of black polyester woven textile piece and 150 ml of deionized water were added into the decolorization reactor of the non-contact type decolorization system as shown in FIG. 2. The decolorization reactor was heated to 140° C. using microwave irradiation, and ultrasonic treatment was performed for 1 hour. After reaction, the polyester cloth was taken out from the mixture.

(25) FIG. 5 shows photos of the cross-linked PS beads before and after decolorization, and of the polyester textile pieces before and after decolorization. After reaction, the color of the PS beads changed from colorless to dark, while the color of the polyester cloth remarkably turned pale. This suggests that the cross-linked PS beads were able to effectively eliminate the dye molecules from the polyester textile piece.

Example 4. Synthesis of Magnetic Activated Carbon Particles

(26) 0.60 g of iron (II) chloride tetrahydrate (FeCl.sub.2.4H.sub.2O) and 1.62 g of iron (III) chloride hexahydrate (FeCl.sub.3.6H.sub.2O) were dissolved in 5 ml of deionized water. After 10 g of activated carbon particles were added, 3M ammonium solution was added dropwise into the mixture of Fe/activated carbon particles. The mixture solution was placed into an oven at 150° C. for 20 mins. The resultant magnetic activated carbon particles were collected, and washed with deionized water several times, followed by drying, giving magnetic activated carbon particles containing 2.0% of iron oxides.

(27) FIG. 6 shows the typical magnetization-magnetic field (M-H) curve of the magnetic activated carbon particles. As can be seen from FIG. 6, the saturation magnetization (M.sub.s) of the magnetic activated carbon particles was 1.16 emu/g.

(28) The above examples are described to facilitate understanding and application of the present invention by those skilled in the art. Those skilled in the art apparently may readily make various modifications to these examples, and apply the general principles described herein to other examples without creative work. Therefore, the present invention is not limited to the specific examples disclosed herein, and any improvements and modifications made by those skilled in the art according to the principles of the present disclosure without departing from the scope of the present disclosure should fall within the scope of protection of the present invention.