阅读说明：本技术 一种提高废弃涤纶布料酶降解效率的化学预处理方法 (Chemical pretreatment method for improving enzyme degradation efficiency of waste polyester cloth ) 是由 董维亮 陈银萍 薛瑞 姜岷 许斌 周杰 于 2021-03-08 设计创作，主要内容包括：本发明公开一种提高废弃涤纶布料酶降解效率的化学预处理方法,包括：将洁净、干燥的废弃涤纶布料溶于有机溶剂中,得到涤纶溶液,之后倒入水中,使得涤纶析出,后加入到含有涤纶降解酶LCC的酶催化体系中,于pH=8,温度67℃条件下进行涤纶的酶降解。采用本发明的方法,能将涤纶废弃布料的结晶度从45%降低到约40%,能将原本不可直接生物降解的废弃涤纶的酶降解效率提高到56%。与现有的技术相比,本方法具有绿色无污染、可操作性强、降解率大幅提高的特点。(The invention discloses a chemical pretreatment method for improving the enzyme degradation efficiency of waste polyester cloth, which comprises the following steps: dissolving clean and dry waste polyester cloth in an organic solvent to obtain a polyester solution, then pouring the polyester solution into water to separate out polyester, then adding the polyester solution into an enzyme catalysis system containing polyester degrading enzyme LCC, and carrying out enzymatic degradation on the polyester under the conditions of pH =8 and temperature 67 ℃. By adopting the method, the crystallinity of the waste terylene cloth can be reduced from 45 percent to about 40 percent, and the enzyme degradation efficiency of the originally nondirectly biodegradable waste terylene can be improved to 56 percent. Compared with the prior art, the method has the characteristics of no pollution, strong operability and greatly improved degradation rate.)

1. A chemical pretreatment method for improving the enzyme degradation efficiency of waste polyester cloth is characterized by comprising the following steps:

(1) dissolving clean and dry waste polyester cloth in an organic solvent to obtain a polyester solution;

(2) pouring the terylene solution into water to separate out terylene and obtain recrystallized terylene;

(3) and (3) adding the recrystallized terylene obtained in the step (2) into an enzyme catalysis system containing terylene degrading enzyme LCC, and carrying out enzyme degradation on the terylene at the temperature of 67 ℃ and the pH = 8.

2. The pretreatment method according to claim 1, wherein the clean, dried waste polyester cloth in the step (1) is obtained by a method comprising:

and cleaning the waste polyester cloth, removing surface stains, and drying.

3. The pretreatment method according to claim 1, wherein the step (1) further comprises a step of pulverizing the dried waste polyester cloth into a yarn shape.

4. The pretreatment method according to claim 1, wherein the organic solvent in the step (1) is hexafluoroisopropanol.

5. The pretreatment method according to claim 1, wherein the step (2) further comprises a step of drying the precipitated polyester.

6. The pretreatment method according to claim 5, wherein the drying temperature is 65 ℃.

7. The pretreatment method according to claim 1, wherein the volume ratio of the organic solvent to water in step (2) is 1: 20.

8. The pretreatment method according to claim 1, wherein the step (3) is carried out in a magnetic stirring water bath.

9. The pretreatment method according to claim 1, wherein the rotational speed of the enzymatic degradation in the step (3) is 120 rpm/min.

Technical Field

The invention belongs to the technical field of bioengineering, and particularly relates to a chemical pretreatment method for improving the enzyme degradation recovery efficiency of waste polyester cloth.

Background

With the growing population and pursuit of fashion, the production of textiles, including polyester, is expanding and the enormous production volume is increasing the amount of waste polyester. Polyester (PET) is a semi-crystalline thermoplastic resin formed by polycondensation of terephthalic acid (TPA) and Ethylene Glycol (EG), and has the advantages of stable chemical structure, high crystallinity and difficult biodegradation.

At present, the recovery mode of the waste terylene mainly comprises a physical method and a chemical method, wherein the former comprises a melting granulation mode and the like, and the latter comprises a hydrolysis method, an alcoholysis method and the like. Melt granulation is the direct preparation of waste polyester into chips by blending. The hydrolysis method comprises acidic hydrolysis, alkaline hydrolysis and neutral hydrolysis, and breaks the macromolecular chains of the terylene by water, acid-base reagent and the like under certain temperature and pressure conditions. For example, the terylene can be degraded under certain temperature and pressure conditions by using excessive methanol or ethanol.

The recycling treatment modes have the defects of easy environmental pollution, easy reagent corrosion on equipment, complex process and the like.

Disclosure of Invention

Aiming at the problems, the invention provides a chemical pretreatment method for improving the enzymatic degradation efficiency of waste polyester cloth.

The purpose of the invention is realized by the following technical scheme:

a chemical pretreatment method for improving the enzyme degradation efficiency of waste polyester cloth comprises the following steps:

(1) dissolving clean and dry waste polyester cloth in an organic solvent to obtain a polyester solution;

(2) pouring the terylene solution into water to separate out terylene and obtain recrystallized terylene;

(3) and (3) adding the recrystallized terylene obtained in the step (2) into an enzyme catalysis system containing terylene degrading enzyme LCC, and carrying out enzyme degradation on the terylene at the temperature of 67 ℃ under the condition that the pH value is 8.

Preferably, the clean and dry waste polyester cloth in the step (1) is obtained by the following method:

and cleaning the waste polyester cloth, removing surface stains, and drying.

Preferably, the step (1) further comprises a step of pulverizing the dried waste polyester fabric into a yarn shape.

Preferably, the organic solvent in step (1) is hexafluoroisopropanol.

Preferably, the step (2) further comprises a step of drying the precipitated terylene. Preferably, the temperature of drying is 65 ℃.

Preferably, the volume ratio of the organic solvent to the water in the step (2) is 1: 20.

Preferably, step (3) is carried out in a magnetically stirred water bath.

Preferably, the rotation speed of the enzymatic degradation in the step (3) is 120 rpm/min.

Compared with the prior art, the method has the advantages that after the crystallization degree of the terylene is reduced by chemical pretreatment, the waste terylene is degraded and recovered by innovatively using an enzyme hydrolysis mode, compared with the prior recovery treatment mode, the method is green and pollution-free, has strong operability, and can ensure that the enzyme degradation rate of the originally non-biodegradable terylene reaches 56%.

Drawings

FIG. 1 is a DSC test chart of original terylene and different chemical pretreatment conditions, wherein a is original waste terylene, b is standing for 4h after terylene is separated out, and c is standing for 12h after terylene is separated out.

FIG. 2 shows the degradation efficiency of dacron enzyme under different chemical pretreatment conditions, wherein a is standing for 4h after dacron is separated out, and b is standing for 12h after dacron is separated out.

Detailed description of the preferred embodiments

The invention is described in detail below with reference to the figures and the specific examples.

Example 1

(1) 10 g-20 g of waste polyester cloth is recycled, cleaned by water and then cleaned and disinfected by 75% alcohol, and the cleaned and disinfected polyester cloth is put into a drying oven at 65 ℃ for drying for 4 hours.

(2) Cutting the clean and dry terylene in the step (1) into uniform fragments of 4cm by 4 cm.

(3) And (3) putting the polyester chips obtained in the step (2) into a crusher to be crushed for 5min, so that the polyester chips are changed into thread shapes.

(4) And (3) putting 5g of the polyester yarn in the step (3) into a 50mL small beaker, measuring 15mL of hexafluoroisopropanol by using a measuring cylinder, pouring into the small beaker, and slightly stirring by using a glass rod to fully dissolve the polyester yarn in the hexafluoroisopropanol.

(5) Measuring 300mL of water by using a measuring cylinder, pouring the water into a 500mL beaker, pouring the hexafluoroisopropanol solvent dissolved with the terylene in the step (4) into the water, and re-separating out the dissolved terylene, wherein the volume ratio of the hexafluoroisopropanol to the water is 1: 20; standing for 4h after the terylene is separated out.

(6) And (5) carrying out suction filtration on the hexafluoroisopropanol solution containing the precipitated terylene in the step (5) by using a circulating water type vacuum pump, and repeatedly carrying out suction filtration for 3-4 times by using pure water after the hexafluoroisopropanol is completely subjected to suction filtration so as to remove hexafluoroisopropanol residues on the surface of the terylene.

(7) Collecting the filtered terylene powder in a disposable culture dish, and drying in an oven at 65 ℃ for 4 h.

(8) 100mL of PBS buffer (pH 8.0), 0.4mg of PET degrading enzyme LCC, and 400mg of the Dacron powder obtained in step (7) were added to a 200mL serum bottle. Carrying out enzyme catalysis reaction in a magnetic stirring water bath kettle, wherein the enzyme catalysis reaction conditions are as follows: the pH value is 8.0, the temperature is 67 ℃, the reaction time is 48 hours, and the rotating speed is 120 rpm/min.

(9) And (4) sampling the enzymatic degradation system in the step (8) at regular time, wherein the sampling is carried out once every 12h until the reaction is finished after 48h, namely, the sampling is carried out when the reactions are carried out for 12h, 24h, 36h and 48 h.

(10) And (3) carrying out Differential Scanning Calorimetry (DSC) on the dried terylene powder 3mg in the step (7) and the original terylene 3mg in the step (1), and detecting the crystallinity change before and after the terylene pretreatment.

Detection conditions of the instrument: the temperature is 50-300 ℃, the temperature rising and falling speed is 10 ℃/min, and the fillerThe inflation body is nitrogen. The method for calculating the crystallinity comprises the following steps:

comparing the original terylene crystallinity before chemical pretreatment (figure 1a) and the terylene crystallinity after chemical pretreatment (1b), the terylene crystallinity after pretreatment is obviously reduced.

(11) The crystallinity of the original terylene is about 45 percent, and the crystallinity after chemical pretreatment is reduced to 42 percent.

(12) And (4) taking the enzyme reaction liquid in the step (9), and detecting the generation of a terylene degradation product terephthalic acid (TPA) and a byproduct MHET in the degradation process by high performance liquid chromatography so as to calculate the degradation rate of terylene. And calculating the concentrations and products of the generated degradation product TPA and the byproduct MHET according to the liquid phase peak areas in the reaction time of 12h, 24h, 36h and 48h, thereby calculating the degradation rate of the terylene.

(13) After the terylene is chemically pretreated, 24.31mg of TPA and 21.20mg of MHET are generated after 48 hours of enzyme reaction, the final TPA equivalent is 38.16mg (figure 2a), and the terylene degradation rate is 36.79%.

Example 2

(1) 10 g-20 g of waste polyester cloth is recycled, cleaned by water and then cleaned and disinfected by 75% alcohol, and the cleaned and disinfected polyester cloth is put into a drying oven at 65 ℃ for drying for 4 hours.

(2) Cutting the clean and dry terylene in the step (1) into uniform fragments of 4cm by 4 cm.

(3) And (3) putting the polyester chips obtained in the step (2) into a crusher to be crushed for 5min, so that the polyester chips are changed into thread shapes.

(4) And (3) putting 5g of the polyester yarn in the step (3) into a 50mL small beaker, measuring 15mL of hexafluoroisopropanol by using a measuring cylinder, pouring into the small beaker, and slightly stirring by using a glass rod to fully dissolve the polyester yarn in the hexafluoroisopropanol.

(5) Measuring 300mL of water by using a measuring cylinder, pouring the water into a 500mL beaker, pouring the hexafluoroisopropanol solvent dissolved with the terylene in the step (4) into the water, and re-separating out the dissolved terylene, wherein the volume ratio of the hexafluoroisopropanol to the water is 1: 20; standing for 12h after the terylene is separated out.

(6) And (5) carrying out suction filtration on the hexafluoroisopropanol solution containing the precipitated terylene in the step (5) by using a circulating water type vacuum pump, and repeatedly carrying out suction filtration for 3-4 times by using pure water after the hexafluoroisopropanol is completely subjected to suction filtration so as to remove hexafluoroisopropanol residues on the surface of the terylene.

(7) Collecting the filtered terylene powder in a disposable culture dish, and drying in an oven at 65 ℃ for 4 h.

(8) 100mL of PBS buffer (pH 8.0), 0.4mg of PET degrading enzyme LCC, and 400mg of the Dacron powder obtained in step (7) were added to a 200mL serum bottle. Carrying out enzyme catalysis reaction in a magnetic stirring water bath kettle, wherein the enzyme catalysis reaction conditions are as follows: the pH value is 8.0, the temperature is 67 ℃, the reaction time is 48 hours, and the rotating speed is 120 rpm/min.

(9) And (4) sampling the enzymatic degradation system in the step (8) at regular time, wherein the sampling is carried out once every 12h until the reaction is finished after 48h, namely, the sampling is carried out when the reactions are carried out for 12h, 24h, 36h and 48 h.

(10) And (3) carrying out Differential Scanning Calorimetry (DSC) on the dried terylene powder 3mg in the step (7) and the original terylene 3mg in the step (1), and detecting the crystallinity change before and after the terylene pretreatment.

Detection conditions of the instrument: the temperature range is 50-300 ℃, the temperature rising and reducing speed is 10 ℃/min, and the filling gas is nitrogen. The method for calculating the crystallinity comprises the following steps:

comparing the original terylene crystallinity before chemical pretreatment (figure 1a) and the terylene crystallinity after chemical pretreatment (1c), the terylene crystallinity after pretreatment is obviously reduced.

(11) The crystallinity of the original terylene is about 45 percent, and the crystallinity after chemical pretreatment is reduced to 40 percent.

(12) And (4) taking the enzyme reaction liquid in the step (9), and detecting the generation of a terylene degradation product terephthalic acid (TPA) and a byproduct MHET in the degradation process by high performance liquid chromatography so as to calculate the degradation rate of terylene. And calculating the concentrations and products of the generated degradation product TPA and the byproduct MHET according to the liquid phase peak areas in the reaction time of 12h, 24h, 36h and 48h, thereby calculating the degradation rate of the terylene.

(13) After the terylene is chemically pretreated, 35.89mg of TPA and 35.66mg of MHET are generated after 48 hours of enzyme reaction, the final TPA equivalent is 59.19mg (figure 2b), and the terylene degradation rate is 56.12%.