CN-122013570-A - Decoloring method of waste polyester fabrics

Abstract

The invention discloses a decoloring method of waste polyester fabrics, which adopts a nonionic high polymer solvent as a decoloring medium and realizes repeated decoloring of the solvent and efficient decoloring of waste washing fabrics through decoloring, adsorption and recovery. The method has the advantages that the decoloring rate is stabilized at more than 98%, various color disperse dyes can be deeply removed, the structural integrity of the decolored polyester fiber is good, the crystallinity is only slightly reduced, the subsequent recycling is not influenced, the solvent can be recycled for more than 5 times, the environmental burden and the production cost are greatly reduced, the method is suitable for waste polyester fabrics with different sources and colors, and the industrialized application prospect is good.

Inventors

• CAO JINGJING
• Dong Jiachen
• FU SHAOHAI

Assignees

• 江南大学

Dates

Publication Date

20260512

Application Date

20260318

Claims (10)

1. 1. The decoloring method of the waste polyester fabric is characterized by comprising the following steps of: Adding waste polyester fabrics into a solvent, heating for decoloring, and carrying out solid-liquid separation to obtain decolored fabrics and colored solutions respectively; adding activated carbon into the colored solution, adsorbing, and performing solid-liquid separation to obtain a colorless solvent; And (3) replacing the colorless solvent in the step (1), and repeating the operations of the steps (1) and (2).
2. 2. The method for decoloring the waste polyester fabric according to claim 1, wherein in the step (1), the solvent is any one of polyethylene glycol, ethylene glycol, diethylene glycol, benzyl alcohol, N-octanol, isooctyl alcohol, methyl benzoate, ethyl benzoate, gamma-valerolactone, propylene carbonate, N-dimethylformamide, N-dimethylacetamide, dimethyl sulfoxide, dipropylene glycol dimethyl ether, diethylene glycol butyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and isosorbide dimethyl ether.
3. 3. The method for decoloring the waste polyester fabric according to claim 1, wherein in the step (1), the mass-volume ratio of the waste polyester fabric to the solvent is 1:20-1:30 g/mL.
4. 4. The method for decoloring the waste polyester fabric according to claim 1, wherein in the step (1), the temperature for heating and decoloring is 80-200 ℃, and the time for heating and decoloring is 10-80 minutes.
5. 5. The method for decoloring waste polyester fabrics according to claim 1, wherein in the step (2), the mass-volume ratio of the activated carbon to the colored solvent is 0.01-0.1 g/5mL.
6. 6. The method for decoloring waste polyester fabrics according to claim 1, wherein in the step (2), the adsorption temperature is 80-180 ℃ and the adsorption time is 1-3 hours.
7. 7. The method for decoloring the waste polyester fabric according to claim 1, wherein in the step (1), the solvent is polyethylene glycol, the mass-volume ratio of the waste polyester fabric to the solvent is 1:25g/mL, the temperature for heating and decoloring is 160 ℃, the time for heating and decoloring is 60 minutes, the mass-volume ratio of the activated carbon to the colored solvent is 0.02g/5mL, the temperature for adsorbing is 150 ℃, and the time for adsorbing is 2 hours.
8. 8. The method for decoloring waste and old polyester fabrics according to claim 1, wherein the operations of steps (1) and (2) are repeated at least five times.
9. 9. The method for decoloring waste and old polyester fabrics according to claim 8, wherein the decoloring rate of the waste and old polyester fabrics is above 99% in each operation.
10. 10. The method for decoloring waste polyester fabrics according to claim 1, wherein the waste polyester fabrics in the step (1) are obtained after the fabrics are subjected to water washing and drying.

Description

Decoloring method of waste polyester fabrics Technical Field The invention relates to the field of textile fiber decolorization and dye recovery, in particular to a method for decolorizing waste polyester fabrics. Background Polyester is the fiber with highest global yield, accounts for 57% of the total yield of the fiber, and is mainly composed of polyethylene terephthalate (PET), and is widely applied to the fields of clothing, home textiles and industry. A large amount of waste polyester fabrics are discarded every year, most of the waste polyester fabrics are disposed in a burning or landfill mode, so that not only is resources wasted, but also soil, water quality and atmosphere are polluted. The current recovery mode of the waste polyester fabrics mainly comprises physical recovery and chemical recovery. The physical recovery mode mainly depends on mechanical processing, and waste polyester fabrics are made into fibers or particles again through steps of cutting, melting and the like. The chemical recovery mode mainly depolymerizes polyester waste into monomers or oligomers through hydrolysis, glycolysis, methanolysis and other modes, and recycles the monomers or oligomers. Regardless of the recycling mode, the influence of the components such as dye, chemical auxiliary agent, finishing agent and the like in the waste polyester fabrics cannot be ignored, and the existence of the chemical substances can reduce the quality of the recycled products and limit the recycling of the recycled products. Therefore, the dye in the polyester fiber is removed, and the positive pushing effect is achieved on the recovery process of the waste polyester fabric. The existing decoloring method has the defects that the traditional oxidation method is vulnerable to damage to a fiber structure, the strength of a fabric is reduced, the wastewater treatment difficulty is high, the reduction method is incomplete in decoloring, the stability of a reducing agent is poor, the storage and use requirements are strict, the novel enzymatic method is low in decoloring efficiency and long in time consumption, the cost of ozone decoloring equipment is high, the energy consumption is high, the photocatalytic decoloring is limited by illumination conditions and influences the fiber performance, the supercritical fluid decoloring is under high temperature and high pressure conditions, the equipment requirement is high, and the problems of easiness in volatilization, high toxicity, environmental pollution and the like exist in part of organic solvents used in the existing solvent extraction decoloring. Therefore, developing a waste polyester fabric decoloring method which is efficient, environment-friendly, low in cost and capable of maintaining fiber performance becomes an urgent need for sustainable development of textile industry. Disclosure of Invention The invention aims to overcome the defects of the prior art and provide a method for decoloring waste polyester fabrics, which is characterized in that a nonionic high polymer solvent is adopted as a decoloring medium, and repeated decoloring of the solvent and efficient decoloring of waste washing fabrics are realized through decoloring-adsorption-recycling. In order to solve the technical problems, the invention discloses a decoloring method of waste polyester fabrics, which comprises the following steps: Adding waste polyester fabrics into a solvent, heating for decoloring, and carrying out solid-liquid separation to obtain decolored fabrics and colored solutions respectively; adding activated carbon into the colored solution, adsorbing, and performing solid-liquid separation to obtain a colorless solvent; And (3) replacing the colorless solvent in the step (1), and repeating the operations of the steps (1) and (2). Preferably, in step (1), the solvent is polyethylene glycol (PEG, mn=400 Da, boiling point >250 ℃), ethylene glycol (EG, boiling point 197.3 ℃), diethylene glycol (DEG, boiling point 245 ℃), benzyl alcohol (BA, boiling point 205 ℃), N-octanol (N-Octanol, boiling point 195.2 ℃), isooctanol (i-Octanol, boiling point 183-185 ℃), methyl benzoate (MB, boiling point 199.6 ℃), ethyl benzoate (EB, boiling point 212.6 ℃), gamma valerolactone (GVL, boiling point 207-208 ℃), propylene carbonate (PC, boiling point 242 ℃), N-dimethylformamide (DMF, boiling point 153 ℃), N-dimethylacetamide (DMAc, boiling point 166.1 ℃), dimethyl sulfoxide (DMSO, boiling point 189 ℃), dipropylene glycol dimethyl ether (dpgdgdg, 175-178 ℃), diethylene glycol butyl ether (DEGBE, boiling point 230-231 ℃), polyethylene glycol diglycidyl ether (PEGDGE), diethylene glycol diglycidyl ether (250 ℃), polypropylene glycol (ppge, boiling point 212.6 ℃), diethylene glycol (25 ℃), diethylene glycol, boiling point 205 ℃), ethylene glycol (25 °) and (25 °) of any of the water-glycol, 25 ° -25 ℃), N-dimethyl acetamide (mg, boiling point 153 ℃), boiling point 195.2 ℃), isooctanol (i-Octanol, boiling point 183-185 ℃), mo