System for separating blended fabric by biological method

Abstract

The utility model provides a system for separating blended fabric through a biological method, the blended fabric is PET and cotton blended fabric, and the system comprises: (1) an ultrasonic generator for performing ultrasonic treatment on PET and cotton blended fabric waste; the enzyme hydrolysis reactor (2) is used for enabling the waste subjected to ultrasonic treatment to be subjected to an enzymolysis reaction; the system enables PET and cotton in the blended fabric waste to be separated from each other.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a system for processing textile waste and a method of using the same. In particular, it relates to a system for polyethylene terephthalate (PET) and cotton blended textile materials using ultrasonic pretreatment and enzymatic hydrolysis and a method of using the same, which separates PET and cotton from each other in textile waste. BACKGROUND

[0002] Textile materials take a long time to decompose in landfills. Polyester such as polyethylene terephthalate (PET) and cotton are very common textile materials. Textile recycling technologies have been developed to cope with the increase in textile waste, especially PET and cotton.

[0003] Hydrothermal treatment is one of the common chemical methods for separating PET / cotton blended textile materials into PET and cellulose powder. The PET and cellulose powder recovered from hydrothermal treatment are reusable, achieving the goal of "end-to-end recycling", i.e. converting post-consumer textiles into raw materials for the production cycle. However, as the amount of textile waste increases, it is very important to seek multiple solutions to collect and recycle PET and cotton.

[0004] Biological methods using enzymatic hydrolysis have been developed in HKRITA-supported projects. The experimental results are good, which is a positive result, and an industrial-scale system is currently needed to develop an industrialized biological treatment process. UTILITY MODEL CONTENT

[0005] To solve the problems existing in the prior art, the present disclosure provides a biological method of enzymatic hydrolysis for recycling textile waste materials using ultrasonic pretreatment and a system for implementing the biological method (more suitable for an industrial-scale prior to industrialization). In the biological method, cotton in blended textiles is hydrolyzed and converted into glucose, and PET is collected for recycling.

[0006] According to one aspect, the present disclosure provides a method of processing blended textile waste of PET and cotton, the method comprising:

[0007] (1) an ultrasonic pretreatment step; and

[0008] (2) an enzymatic hydrolysis step;

[0009] The method separates PET and cotton from each other in textile waste.

[0010] According to some embodiments, in the method of processing textile waste, the enzymes used in the enzymatic hydrolysis step include, but are not limited to, cellulase and glucosidase, such as neutral polishing enzyme.

[0011] According to some embodiments, in the method of treating textile waste, the pH of the reaction solution in the enzymatic hydrolysis step is 3 to 7 (preferably 4-6).

[0012] According to some embodiments, in the method of treating textile waste, in the enzymatic hydrolysis step, the reaction temperature is between 20°C and 70°C, preferably between 30-60°C; the reaction time is 8 hours to 72 hours, preferably 12-24 hours; and / or the enzyme content in the reaction solution is 0.1-20wt% (preferably 1-10wt%).

[0013] According to some embodiments, in the method of treating textile waste, in the enzymatic hydrolysis step, the buffer added is a citric acid-sodium citrate buffer, and the concentration of the buffer is 0.001M-0.1M.

[0014] According to some embodiments, the method of treating textile waste further comprises:

[0015] (3) a first filtration step to remove PET from the reaction solution to obtain a cellulose-glucose mixture.

[0016] According to some embodiments, the method of treating textile waste further comprises:

[0017] (4) a second filtration step to separate the cellulose powder in the cellulose-glucose mixture from the glucose solution, and filter out the glucose solution.

[0018] According to some embodiments, the method of treating textile waste further comprises:

[0019] (5) a decolorization and ion exchange step to subject the filtered glucose solution to decolorization and ion exchange (weak anion exchange resin and strong acid cation resin) treatment to decolorize the solution and remove enzymes and other soluble impurities therein.

[0020] According to some embodiments, the method of treating textile waste further comprises:

[0021] (6) a concentration step to concentrate the glucose solution obtained in step (5) to obtain a glucose syrup with a glucose concentration of 10g / L to 100g / L.

[0022] According to another aspect, the present disclosure provides a system for treating blended textile waste of PET and cotton, the system comprising:

[0023] (1) an ultrasonic generator for ultrasonic treatment of blended textile waste of PET and cotton; and

[0024] (2) an enzymatic hydrolysis reactor for subjecting the ultrasonically treated textile waste to enzymatic hydrolysis reaction;

[0025] The system separates PET and cotton from each other in the blended fabric waste.

[0026] According to some embodiments, the system provided by the present disclosure comprises:

[0027] (1) an ultrasonic generator for generating mechanical sound waves with a frequency ≥20 kHz;

[0028] (2) a reactor for performing enzymatic hydrolysis reaction, the reactor comprising a stirrer, preferably the stirrer has paddles or turbine blades, more preferably large paddles.

[0029] According to some embodiments, the system further comprises:

[0030] (3) a first filter device for removing PET from the reaction solution to obtain a cellulose-glucose mixture; and

[0031] (4) a second filter device for separating cellulose and glucose solution in the cellulose-glucose mixture, and filtering out the glucose solution;

[0032] According to some embodiments, the system further comprises:

[0033] (5) a decolorizing agent container for decolorizing the filtered glucose solution; and / or

[0034] (6) an ion exchange column for removing enzymes and other impurities in the glucose solution;

[0035] According to some embodiments, the system further comprises:

[0036] (7) a glucose solution storage and evaporation tank for collecting and concentrating the filtered glucose solution.

[0037] According to some embodiments, in the system, the second filter, for example, Nutsche filter and scraper filter, has a pore size ranging from 1 to 200 microns, preferably 50 to 100 microns.

[0038] According to some embodiments, the pore size of the first filter device (PET filter device) must be larger than that of the second filter device.

[0039] The system of the present disclosure is a hardware system for separating cotton and PET, mainly comprising two reactors, with a maximum working pressure of 10 bar, a maximum temperature of 180°C, and a pH value of the reaction solution of about 2-6. Therefore, the system needs to run the process of the present disclosure for treating textile waste in this environment. An ultrasonic device can be installed inside the reactor. The system contains two filtration devices. The first filtration device is used to remove PET, obtaining a cellulose-glucose mixture. In the second filtration device, the cellulose powder in the cellulose-glucose mixture is retained, and the glucose solution is filtered out. The filter is, for example, a Nutsche filter or a scraper filter, but can also be a centrifuge. The glucose solution is then transferred to a decolorizing tank and ion exchange column to decolorize the solution and remove the enzymes. Weak anion exchange resin and strong acid cation exchange resin are used to remove enzymes and impurities in the glucose solution, respectively.

[0040] The purified glucose solution is further concentrated to obtain glucose syrup in a glucose storage and evaporation tank.

[0041] The method for treating textile waste of the present disclosure can also be applied in a garment dyeing / washing container.

[0042] According to certain embodiments of the present disclosure, the present disclosure provides a system for recycling textile raw materials using enzymatic hydrolysis, which comprises (1) an ultrasonic generator for generating mechanical sound waves with a frequency of >20 kHz; (2) a reactor for biological treatment. The reactor contains a stirrer (with paddles or turbine blades) for mixing and stirring the textile waste material. The solution inside the reactor forms a large number of microbubbles, and the collapse of the bubbles will cause microjets to move at high speed towards the solid surface.

[0043] According to some embodiments, the system further comprises a container for storing a decolorizing agent such as activated carbon, and a decolorizing agent such as activated carbon.

[0044] According to some embodiments, the system further comprises an ion exchange column for storing ion exchange resin to remove enzymes from the glucose solution.

[0045] According to a further technical aspect of the present disclosure, the system further comprises (1) a PET and cellulose delivery pump for delivering liquid PET and cellulose material; (2) a PET and cellulose filtration device.

[0046] According to a further embodiment of the present disclosure, the system further comprises (1) a glucose solution buffer tank for temporarily storing the glucose solution; (2) a glucose solution delivery pump for delivering glucose liquid, and (3) a glucose solution storage and evaporation tank for collecting and concentrating the filtered glucose solution.

[0047] According to a further aspect of the present disclosure, the system further comprises (1) a washing water delivery pump for delivering the liquid containing the cellulose particles; (2) a cellulose filter device for retaining the cellulose material and (3) a cellulose storage tank for collecting the cellulose powder obtained after filtration.

[0048] According to a further aspect of the present disclosure, the system further comprises (1) a washing storage tank for collecting the washing water and (2) a washing water circulation pump for delivering the water in the washing water storage tank to the filter device.

[0049] The textile waste of the present disclosure includes, but is not limited to, cloth, fabric and fiber.

[0050] According to some embodiments, the system further comprises (1) a cold trap and vacuum pump for condensing all vapors except permanent gases; (2) a CIP (clean-in-place) system for recirculating cleaning solutions to flush and rinse the equipment or vessels with water or solutions, (3) a heat source equipment such as a heat conducting oil system for providing heat conducting oil for heating the reactor and other vessels if necessary; (4) an upper inlet and a lower outlet for the material to enter and exit.

[0051] The biological method and system of the present disclosure have at least the following advantages: high recovery rate of raw materials, high purity, for example, the purity and recovery rate of PET is nearly 100%; and, low energy consumption, saving energy. BRIEF DESCRIPTION OF DRAWINGS

[0052] Figure 1 A process flow of the method of processing fabric waste of the present disclosure is shown.

[0053] Figure 2 An example diagram of the system of the present disclosure is shown.

[0054] Figure 2 In the embodiment, the reactor is a jacketed heating reactor, which is installed with a stirring device of large paddle blades.

[0055] REFERENCE NUMERALS

[0056] 11, 21 reactor

[0057] 12, 22 upper inlet

[0058] 13, 23 lower outlet

[0059] 14, 24 heating valve

[0060] 15, 25 water inlet valve

[0061] 16, 26 stirring blade

[0062] 17, 18, 27, 28 ultrasonic generator

[0063] 32, 34 PET filtering device (first filtering device)

[0064] 33, 35 delivery pump

[0065] 36 cellulose filtering device (second filtering device)

[0066] 41 water supply line

[0067] 42 heat source device

[0068] 43, 44 ventilation line

[0069] 45 heat conducting oil pump

[0070] 46 heat exchanger DETAILED DESCRIPTION

[0071] The accompanying drawings, where like reference numerals refer to identical or functionally similar elements or components, contain some embodiments of the present disclosure to further illustrate and clarify the various aspects, advantages, and features of the methods and systems for separating textile materials disclosed herein. It will be understood that these drawings and illustrations are only meant to depict certain embodiments of the present disclosure and are not intended to limit the scope thereof. The biological separation methods and systems disclosed herein will be described and explained in detail with the aid of the accompanying drawings, wherein:

[0072] The system of the present disclosure is a hardware for separating cotton and PET, mainly comprising a reactor, which can be two reactors running almost simultaneously or in series. An ultrasonic device can be installed directly in the reactor for pretreatment or to assist in the separation of textile materials, where the treated fabric can be clothes, fabrics, and fibers. The pretreatment step is carried out by the ultrasonic generator generating mechanical sound waves with a frequency ≥ 20 kHz. The ultrasonic waves generated by the ultrasonic generator consist of mechanical sound waves in the frequency range from 20 kHz to 500 MHz. These waves cause the formation of a large number of microbubbles in the liquid medium. The collapse of the bubbles generates microjets that move at high speed towards the surface of the solid, thus creating local hot spots with a temperature increase, thus promoting mass transfer and chemical reactions. Due to the formation of microjets, the ultrasonic waves erode the internal structure of the textile waste. High energy intensity can break down particulate matter, thus reducing particle size. In the subsequent enzymatic hydrolysis, the textile material is more easily absorbed by the enzyme, allowing the cotton in the blended textile to be broken down into cellulose and glucose, while the PET can be separated.

[0073] The reaction conditions in the reactor are not less than 20°C and not more than 70°C, preferably between 30-60°C. The enzymes used for the reaction include cellulase and glucosidase, etc. The enzyme content in the reaction solution ranges from 0.1-20%, preferably 1-10%. The pH value ranges from 3-7, preferably 4-6, and a citric acid-sodium citrate buffer solution with a concentration ranging from 0.001M-0.1M is used to maintain the pH value during the reaction. The reaction time ranges from 8 hours to 72 hours, preferably 12-24 hours. A paddle or turbine blade stirrer is installed on the bioreactor, preferably a large paddle stirrer, to make the reaction uniform in the bioreaction process and prevent the formation of unreacted textile mixture. The reactor uses a jacket to heat the reaction mixture by using a heating medium, and is additionally equipped with the stirrer, ultrasonic generator, circulation device and filtration system listed in the present application. In addition, the bioreaction can also be carried out in a garment dyeing / washing container. After the bioprocess, there are two filtration devices that can be performed. The first filtration device separates PET from the cellulose-glucose mixture. In the second filtration device (such as a Nutsche filter or a scraper filter), cellulose powder and glucose solution are separated. The pore size of the Nutsche filter and the scraper filter ranges from 1 to 200 microns, preferably 50 to 100 microns, to separate the glucose solution from the cellulose. The glucose solution is then transferred to a decolorization tank and an ion exchange column to decolorize the solution and remove the enzyme. The purified glucose solution is further concentrated to obtain glucose syrup in the glucose storage and evaporation tank. After decolorization, the solution will perform an ion exchange process to remove the enzyme and other soluble impurities. Weak anion exchange resin and strong acid cation exchange resin are used to remove the enzyme content and impurities in the glucose solution, respectively. Then, the glucose solution treated by the decolorization tank and the ion exchange column is concentrated in the glucose storage and evaporation tank to produce glucose syrup with a glucose concentration ranging from 10g / L to 100g / L.

[0074] In one embodiment, the system of the present disclosure is as shown in Figure 2 In one embodiment, the system of the present disclosure is as shown in

[0075] Figure 2 The system shown includes two reactors and two sets of corresponding post-treatment devices for the enzyme-hydrolyzed reactants. In another embodiment, the system of the present disclosure includes only one reactor and one set of corresponding post-treatment devices for the enzyme-hydrolyzed reactants. In other embodiments, the system of the present disclosure can include more than two reactors and corresponding post-treatment devices for the enzyme-hydrolyzed reactants.

[0076] The system and biological processes of the present disclosure are illustrated by way of example in connection with the following specific examples, but the application is not limited to the examples.

[0077] Example 1

[0078] Twenty kilograms of 55% cotton / 45% PET blended textile waste was mixed with 291 L of deionized water and subjected to ultrasonic pre-treatment at room temperature. The pre-treatment was performed at 30% amplitude for 2 hours. After pre-treatment, the twenty kilograms of 55% cotton / 45% PET blended textile waste was reacted in a 300 L solution containing 3% Novozymes NS59104 enzyme and 0.01 M citric acid-sodium citrate buffer for 24 hours at 50 ± 1 °C and pH 5. An average of 2.8% ± 0.2% insoluble matter remained in the PET fibers. This means that a purity of 97.2% of PET was obtained. The average molecular weight (Mw) of the cellulose powder collected after treatment was 264,596. The tenacity of the PET fibers after treatment was 31.5 ± 0.28 cN / tex, and the initial tenacity was 35.8 ± 0.24 cN / tex. The PET fibers were then spun into yarns having an average tenacity of > 2 g / den (17.7 cN / tex) and elongation of > 10%.

[0079] Example 2

[0080] Twenty kilograms of 55% cotton / 45% PET blended textile waste was mixed with 291 L of deionized water and subjected to ultrasonic pre-treatment at room temperature. The pre-treatment was performed at 60% amplitude for 4 hours. After pre-treatment, the twenty kilograms of 55% cotton / 45% PET blended textile waste was reacted in a 300 L solution containing 3% Novozymes NS29058 enzyme and 0.01 M citric acid-sodium citrate buffer for 48 hours at 50 ± 1 °C and pH 5. An average of 1.6% insoluble matter remained in the PET fibers. This means that a purity of 98.4% of PET was obtained.

[0081] Example 3

[0082] Twenty kilograms of 55% cotton / 45% PET blended knitted fabric waste in yellow, blue and green color were mixed with 291 L of deionized water and subjected to ultrasonic pre-treatment at room temperature. The pre-treatment was carried out for 2 hours at 30% amplitude. After pre-treatment, the twenty kilograms of 55% cotton / 45% PET blended knitted fabric waste was reacted in 300 L solution containing 3% Novozymes NS29058 enzyme and 0.01 M citric acid-sodium citrate buffer for 24 hours at 50 ± 1 °C and pH 5. On an average, 2.4% ± 0.2% insoluble matter was left in the PET fibers. This means that the purity of PET obtained was 97.6%. The average molecular weight (Mw) of the cellulose powder collected after treatment was 292,684.

[0083] Example 4

[0084] Twenty kilograms of 55% cotton / 45% PET blended knitted fabric waste in yellow, blue and green color were mixed with 291 L of deionized water and subjected to ultrasonic pre-treatment at room temperature. The pre-treatment was carried out for 2 hours at 30% amplitude. After pre-treatment, the twenty kilograms of 55% cotton / 45% PET blended knitted fabric waste was reacted in 300 L solution containing 3% Novozymes NS29058 enzyme and 0.01 M citric acid-sodium citrate buffer for 24 hours at 50 ± 1 °C and pH 5. On an average, 2.4% ± 0.2% insoluble matter was left in the PET fibers. This means that the purity of PET obtained was 97.6%. The average molecular weight (Mw) of the cellulose powder collected after treatment was 292,684.

[0083] Example 4

[0084] Twenty kilograms of 55% cotton / 45% PET blended knitted fabric waste in yellow, blue and green color were mixed with 291 L of deionized water and subjected to ultrasonic pre-treatment at room temperature. The pre-treatment was carried out for 2 hours at 30% amplitude. After pre-treatment, the twenty kilograms of 55% cotton / 45% PET blended knitted fabric waste was reacted in 300 L solution containing 3% Novozymes NS29058 enzyme and 0.01 M citric acid-sodium citrate buffer for 24 hours at 50 ± 1 °C and pH 5. On an average, 2.4% ± 0.2% insoluble matter was left in the PET fibers. This means that the purity of PET obtained was 97.6%. The average molecular weight (Mw) of the cellulose powder collected after treatment was 292,684.

Claims

1. A system for biologically separating blended fabrics, wherein the blended fabric is a blend of PET and cotton, characterized in that, The system includes: (1) An ultrasonic generator for ultrasonically treating waste PET and cotton blended fabrics; and (2) Enzymatic hydrolysis reactor, used to cause enzymatic hydrolysis of ultrasonically treated textile waste; The system separates PET and cotton from each other in blended textile waste.

2. The system according to claim 1, characterized in that, The enzyme hydrolysis reactor is equipped with a stirrer.

3. The system according to claim 1 or 2, characterized in that, The system also includes: (3) A first filtration device to remove PET from the reaction solution to obtain a cellulose-glucose mixture; (4) A second filtration device to separate the cellulose and glucose solution and filter out the glucose solution.

4. The system according to claim 3, characterized in that, The system further includes: (5) A decolorizing agent container to decolorize the filtered glucose solution; and / or (6) Ion exchange column, so that the enzymes in the filtered glucose solution are removed.

5. The system according to claim 3, characterized in that, The second filter in the system is a Nutsche filter, a scraper filter, or a centrifuge.

6. The system according to claim 4, characterized in that, The system further includes: (7) Glucose solution storage and evaporation tank for collecting and concentrating glucose solutions after decolorization and / or ion exchange column treatment.

7. The system according to claim 3, characterized in that, The system also includes a cellulose storage tank for collecting the cellulose obtained after filtration by the second filtration device.

8. The system according to claim 3, characterized in that, The system also includes PET storage tanks for collecting the obtained PET.

9. The system according to claim 3, characterized in that, The system also includes a wash water storage tank and a wash water circulation pump for storing wash water and conveying wash water to the filtration device.

10. The system according to any one of claims 1-9, characterized in that, The system includes a reactor (11) containing at least one ultrasonic generator (17) and stirring blades (16). Textile waste can enter the reactor through the upper inlet (12), and water can enter the reactor through the water supply line (41). After ultrasonic pretreatment, the reactor undergoes enzymatic hydrolysis. The enzymatic hydrolysis product then enters the first filtration device (32) through the lower outlet (13), thereby obtaining solid PET. The filtrate is then sent to the second filtration device (36) by a transfer pump (33 / 35), thereby separating the cellulose and glucose solution.

Images