1505 results about "Depolymerization" patented technology

The invention discloses a yellow phosphorus tailing-based mine filling material and application thereof. The yellow phosphorus tailing-based mine filling material comprises aggregate and a cementing material, the cementing material comprises the following components in parts by mass: 5-20 parts of red mud, 20-40 parts of yellow phosphorus slag, 10-30 parts of slag, 5-10 parts of fly ash, 5-10 parts of a compound exciting agent, 1-3 parts of an early strength agent and 2-5 parts of a water-retaining agent; wherein the compound exciting agent comprises the following components in parts by mass: 10-20 parts of sodium metasilicate, 30-40 parts of gypsum powder, 20-30 parts of sodium sulfate, 5-10 parts of carbide slag and 5-10 parts of silica fume; according to the invention, the raw materials are compounded and the specific exciting agent is subjected to depolymerization-polycondensation reaction to obtain a cementing material containing Aft (ettringite), C-S-H gel (hydrated calcium silicate gel) and C-A-S-H gel (hydrated calcium aluminosilicate gel), and finally, the mine filling material with high fluidity, low bleeding rate and high strength is obtained while yellow phosphorus tailing solid waste is treated.

The invention provides a bio-based adhesive and a preparation method thereof. Inspired by a spider thread structure, biomass adhesive interface enhancement based on a tannic acid adhesion group is combined with construction of a differential phase separation structure by biomass-induced polylipoic acid depolymerization, and a brand new strategy of adhesion-cohesion synergistic enhancement of the adhesive strength of the adhesive is realized. According to the invention, tannic acid and carboxymethyl chitosan are introduced into a lipoic acid-based adhesive, so that the purpose of synergistically enhancing the bonding performance of the adhesive through adhesion-cohesion is achieved, and the defects of weak cohesion, low bonding strength, poor water resistance, poor moisture resistance and the like of the conventional biomass adhesive are overcome. Benefited from a new strategy of adhesion-cohesion synergistic enhancement, the biomass adhesive has good adhesive strength in various environments and materials. In addition, the biomass adhesive also has the characteristics of biological safety, antibacterial and mildew-proof properties and recoverability, so that the product has wider application and potential compared with the previous product, and has a good application prospect.

The invention belongs to the technical field of recycled polyester, and particularly relates to a waste polyester textile recycling method which comprises the following steps: decolorizing colored waste polyester textiles by adopting a decolorizing agent which is more than one of dimethyl carbonate, diethyl carbonate and methyl ethyl carbonate; the depolymerization agent is adopted to depolymerize the decolored polyester textile to obtain the terephthalate, and the depolymerization rate of the decolored polyester textile is 98.0-100%; firstly, terephthalate is converted into DMT, and then DMT, ethylene glycol, a catalyst and a functional additive are subjected to a repolymerization reaction to obtain regenerated PET. According to the method, a process of decoloring and depolymerizing sequentially is adopted, and decoloring and depolymerizing are coordinated, so that the process is simplified, the energy consumption and pollution are reduced, and the economical efficiency and sustainability of waste polyester textile recycling are improved.

The present invention relates to the recycling of textiles, and further to a method for recycling polyester blended fabrics. After the raw material containing polyester is treated, the polyester is decomposed by a catalyst at 40°C to 120°C for 0.5 to 8 hours to achieve complete depolymerization, and then separated and recycled, and the separated polyester component and other blended components are reused. The method of the present invention realizes 100% depolymerization of polyester under low temperature conditions, and the depolymerized polyester component can be easily separated from other components, so that the polyester and other temperature-sensitive fiber components in the blended fabric can be completely separated. The polyester depolymerized monomer obtained by recycling can also be used to synthesize new polyester, realizing the closed-loop recycling of different fiber components in polyester blended waste, which is of great importance for protecting the ecological environment and reducing the cost of regenerated fibers.

The invention provides a metal organic sulfonic acid-based solid acid catalyst applied to nylon 6 recovery and depolymerization and a preparation method thereof, and realizes upgrading and recovery of waste nylon 6. The main contents are as follows: (1) a structural design and a preparation method of the metal organic framework sulfonic acid-based solid acid catalyst; and (2) the solid acid is used for catalytic depolymerization of nylon 6. The problems that equipment corrosion is aggravated by inorganic acid in the nylon 6 recovery process and a liquid-phase catalyst is difficult to separate and recover are solved, and the application prospect is good.

The invention discloses a tightening and whitening composition containing EGCG (epigallocatechin gallate) as well as a preparation method and application of the tightening and whitening composition, and relates to the technical field of cosmetics. The invention provides a tightening and whitening composition containing EGCG (epigallocatechin gallate). The tightening and whitening composition is prepared from the following components in parts by weight: 0.1 to 2 parts of an epigallocatechin gallate nano composition, 0.05 to 0.5 part of a nucleic acid tetrahedron and 0.5 to 5 parts of glassine. When the EGCG nano composition, the nucleic acid tetrahedron and the glassine are cooperatively used, the stability of a formula can be improved, meanwhile, the EGCG can be accurately released to an epidermal layer due to the enzyme-responsive degradation characteristic (such as matrix metalloproteinase MMP-2 triggered depolymerization) of the nucleic acid tetrahedron, and the glassine is released after deeply penetrating into a corium layer along with a nucleic acid tetrahedron carrier, so that the EGCG can be accurately released to the epidermal layer. The synergistic effects of the three components on whitening and tightening are better exerted.

The invention discloses a method for preparing regenerated flame-retardant high-shrinkage polyester by a methanol alcoholysis method, and belongs to the technical field of polyester. The method comprises the following steps: (a) mixing the waste polyester fabric with methanol, and carrying out catalytic depolymerization to obtain a regenerated DMT mixed solution; (b) carrying out impurity separation and methanol recovery treatment on the regenerated DMT mixed solution, and then carrying out cooling crystallization, centrifugal drying and rectification purification treatment to obtain pure DMT; (c) carrying out transesterification on pure DMT, ethylene glycol, a transesterification catalyst and a DEG inhibitor; (d) after the ester exchange reaction, adding CEPPA-EG and IPA-EG for copolymerization; adding a polymerization catalyst, a stabilizer and an antioxidant for polymerization reaction to obtain a modified polyester melt; and (e) granulating and drying to obtain the slices. The regenerated polyester prepared by the method has multiple functions of flame retardance, high boiling water shrinkage, low-temperature dyeing and the like, and is suitable for the fields of high-end clothing, automotive trim, electronic packaging materials and the like.

The invention belongs to the technical field of regenerated polyester, and particularly relates to a waste cotton-polyester blended fabric recycling method which comprises the following steps: firstly, decolorizing a colored waste cotton-polyester blended fabric by adopting a decolorizing agent, then mixing a depolymerizing agent, isosorbide dimethyl ether, a first catalyst and the decolorized cotton-polyester blended fabric, and then carrying out depolymerization reaction, the decolorizing agent and the depolymerizing agent are more than one of dimethyl carbonate, diethyl carbonate and methyl ethyl carbonate, and the temperature of the depolymerizing reaction is 130-150 DEG C; washing the separated cotton fibers with water, and screening to remove residual polyester powder on the surfaces; firstly, terephthalate is converted into DMT, and then DMT, ethylene glycol, a second catalyst and a functional additive are subjected to a repolymerization reaction to obtain regenerated polyethylene glycol terephthalate. According to the method, depolymerization and polyester cotton separation processes are ingeniously fused, so that the operation steps are simplified, the energy consumption is reduced, and the purity of a depolymerization product is also improved.

To provide a novel method for depolymerizing polyester utilizing a catalyst that allows for progression of polyester depolymerization reaction and that enables post-reaction recovery, separation, and reuse.SOLUTION: The present invention provides a method for depolymerizing polyester, comprising a step in which polyester is reacted in the presence of a catalyst and solvent to depolymerize, where the catalyst is a boric acid compound.SELECTED DRAWING: None

Disclosed is a method for recycling a polyester blend fabric. The method includes: treating a polyester-containing raw material to be treated, subjecting a resulting treated polyester-containing raw material to polyester degradation at 40° C. to 120° C. for 0.5 h to 8 h in the presence of a catalyst to achieve complete depolymerization, separating out and recovering a polyester component, and reutilizing the polyester component and other blend components.

The invention belongs to the technical field of regenerated polyester, and particularly relates to a waste polyester-spandex blended fabric recovery method, which comprises the following steps: carrying out decoloration and depolymerization on a colored waste polyester-spandex blended fabric by using a treating agent; and depolymerizing the decolored polyester fabric by using a depolymerizing agent to obtain the terephthalate. Wherein the treating agent is more than one of dimethyl carbonate, diethyl carbonate and methyl ethyl carbonate; the depolymerizing agent is the same as the treating agent; the depolymerization rate of spandex in the waste polyester-spandex blended fabric is 98-100%, and the decolorization rate of the waste polyester-spandex blended fabric calculated according to the K / S value is 98% or above. The method breaks through the bottlenecks of high pollution and high energy consumption of the traditional process, and solves the contradiction that component separation and decoloration are difficult to take into account in the recovery process of the blended fabric.

The invention relates to the technical field of recycling and reusing of solar back plates of photovoltaic modules, and discloses a recycling method of a solar back plate. The recovery method of the solar back panel is characterized by comprising the following steps: (1) in the presence of a protective gas and a catalyst, carrying out alcoholysis reaction on the solar back panel and alcohol to obtain a depolymerized mixed solution; and (2) carrying out purification treatment on the depolymerized mixed solution obtained in the step (1) to obtain bis (2-hydroxyethyl) terephthalate (BHET), polyvinylidene fluoride and polyolefin. According to the method, the PET middle layer in the solar panel can be completely depolymerized into the BHET monomer, the yield is greater than or equal to 78%, and the purity is greater than or equal to 98%; pVDF and PP (or PE) products can be respectively obtained after the PVDF and PP (or PE) materials which do not participate in depolymerization are separated and purified; the whole chemical recovery process is simple in operation method and high in efficiency, and has good economic benefits.

The invention provides high-filling silver powder and a preparation method thereof, and belongs to the field of metal powder.The preparation method comprises the steps that a nano-silver solution is prepared, a dispersing agent and a first reducing agent are mixed to obtain a mixed solution, the nano-silver solution and the mixed solution are mixed in a constant-temperature stirring state to obtain a base solution, a second reducing agent solution and a silver nitrate solution are prepared respectively, and the high-filling silver powder is prepared. And under the constant-temperature stirring state, the second reducing agent solution and the silver nitrate solution are synchronously added into the base solution, a silver powder solution is obtained through reaction, the silver powder solution is subjected to washing, solid-liquid separation, drying and depolymerization shaping treatment, and the high-filling silver powder is obtained. Controllable preparation of the large-size sphericity silver powder is achieved by controlling the particle size and the adding amount of the nano-silver, regulating and controlling heterogeneous nucleation and growth sites of silver ions and inhibiting formation of multistage dendritic crystals, surface charges and steric hindrance effects of silver particles are optimized through the surface adsorption effect of the dispersing agent, the agglomeration phenomenon of the silver powder in the growth process is reduced, and the silver powder is prepared. And meanwhile, the silver powder is endowed with excellent flowability.

The present invention relates to a polylactic acid waste recovery system and recovery method in the technical field of environment-friendly regeneration. The system comprises a screw extruder, a depolymerization kettle, an intermediate kettle, a cracking kettle, a deacidification tower, a purification system, a pre-polymerization kettle, a polymerization reactor, a first devolatilization device, a second devolatilization device, a pelletizing system, and a vacuum system; an outlet of the screw extruder is connected to an inlet of the depolymerization kettle; the depolymerization kettle is connected to the intermediate kettle; an outlet of the intermediate kettle is connected to a feeding port of the cracking kettle by means of a second conveying pump; a gas phase outlet of the cracking kettle is connected to a gas phase inlet at the lower portion of the deacidification tower; a hammer condenser is arranged at the top of the deacidification tower; an outlet of the deacidification tower is connected to the purification system; the purification system is connected to the polymerization reactor by means of the pre-polymerization kettle; and the polymerization reactor is connected to a pelletizer by means of the first devolatilization device and the second devolatilization device. Such an apparatus is used for polylactic acid waste recovery, has high recovery efficiency, and can be used for obtaining high-molecular-weight polylactic acid. Additionally, a special catalyst is used for depolymerization, such that the depolymerization and cracking temperatures are reduced, the energy consumption is reduced, and racemization by-products in a lactide product are few.

The invention belongs to the technical field of lignin depolymerization, and particularly relates to a selective fracture method of micromolecular mercaptan mediated lignin beta-O-4 connection. In an H-type electrolytic tank, an anode electrolytic tank takes a buffer solution as an electrolyte, a cathode electrolytic tank takes a lignin beta-O-4 model compound as a reaction substrate, and an acetonitrile / buffer solution mixed solution of small molecular mercaptan is taken as an electrolyte for electrochemical cracking reaction. Wherein a micromolecular mercaptan medium is used as a single electron transfer medium, and can efficiently and selectively break key C beta-O bonds in a lignin beta-O-4 model compound at normal temperature and normal pressure under the catalytic action of current to obtain corresponding phenol and ketone monomers, so that the problems that high temperature, high pressure and expensive catalysts are usually needed in depolymerization in a lignin reduction way are solved.

The invention discloses an efficient purification method of rBHET, and belongs to the technical field of waste polyester recycling. A reaction raw material obtained after premixing of waste PET polyester raw material particles and a catalyst and ethylene glycol are jointly and continuously introduced into a depolymerization reactor, the reaction raw material and ethylene glycol in the depolymerization reactor are mixed and pass through a plurality of rotating discs, and the materials form a flowing film on the rotating discs rotating at a high speed to promote depolymerization; depolymerization reaction liquid generated in the depolymerization reactor enters a temporary storage tank to be stored after being subjected to impurity removal, the depolymerization reaction liquid in the storage tank is introduced into a rectifying tower to be primarily concentrated and purified, obtained concentrated liquid enters an evaporator to be secondarily concentrated and purified, obtained secondary concentrated liquid enters a cooler to be cooled and then enters a product tank to be crystallized; and drying the crystallized solid to obtain a high-purity rBHET product. According to the method, the production efficiency is improved, and the purity of rBHET is effectively improved.

This invention discloses a method for catalytically depolymerizing polyethylene terephthalate (PET) to prepare terephthalate. Under catalyst-free conditions or with a salt as a catalyst, PET or its composite system is treated in diester carbonate to achieve chemical depolymerization of PET, yielding PET monomers terephthalate and ethylene carbonate, and achieving complete depolymerization of PET in the composite. This invention, through the reaction of diester carbonate with PET, enables the depolymerization of PET under mild conditions, and further facilitates the research and development of related technologies for the chemical recovery of PET monomers from PET composite or mixed systems. The method provided by this invention has advantages such as high efficiency, environmental friendliness, and mild reaction conditions, and can catalyze the depolymerization of PET to generate its monomer terephthalate, possessing strong industrial application value.

The invention discloses a platinum-tungsten bimetallic catalyst for PET depolymerization and a method for directional depolymerization of PET by the platinum-tungsten bimetallic catalyst, and belongs to the technical field of solid waste recycling, the platinum-tungsten bimetallic catalyst for PET depolymerization is prepared by a deposition-precipitation method, a mesoporous molecular sieve MCM-48 is used as a carrier to load platinum-tungsten bimetallic, the molar ratio of platinum to tungsten is 1: (0.5-2), the molecular sieve MCM-48 is a mesoporous molecular sieve MCM-48, and the mesoporous molecular sieve MCM-48 is a mesoporous molecular sieve MCM-48 carrier. And the platinum loading capacity is 4-6 wt%. By utilizing the platinum-tungsten bimetallic catalyst, one-pot depolymerization of PET can be realized to prepare p-toluic acid and p-xylene, the platinum-tungsten bimetallic catalyst can be used for multiple times through reduction regeneration, the catalytic activity is high, and the PET depolymerization method under catalysis of the platinum-tungsten bimetallic catalyst is suitable for recycling and upgrading of PET wastes in various forms and has wide application prospects. The technical problems of efficient depolymerization and directional conversion of the waste PET are solved, and a sustainable technical path is provided for resource recycling of the PET.

The invention discloses a fan blade material processing device, which comprises a disintegration furnace, a splitting frame and a fiber claw, the furnace wall of the disintegration furnace is provided with a jet orifice, and the jet orifice is used for jetting a depolymerization liquid towards a blade falling in the disintegration furnace so as to depolymerize organic matters in the blade and separate fibers in the blade, the splitting frame is used for colliding falling blades so as to crush the blades; and the fiber claw is used for grabbing fibers in the depolymerization liquid when the discharging channel discharges the depolymerization liquid. According to the method, the problem of environmental pollution caused by garbage burying or incineration can be effectively reduced, fibers in the leaves can be effectively recycled, and the fibers can be reused in other industrial fields, so that resource waste is reduced. Compared with a traditional treatment method, the device can automatically carry out blade disintegration and fiber separation, the treatment efficiency is improved, the time for workers to make direct contact with waste is shortened, the risk for workers to make direct contact with waste is reduced, and therefore the health and safety of the workers are protected.

The invention discloses a high-purity BHET low-temperature continuous production process which comprises the following steps: (1) uniformly mixing waste PET powder and a catalyst, adding a solvent, stirring and mixing to form a muddy mixture, pumping the muddy mixture and ethylene glycol into a depolymerization kettle, and carrying out a depolymerization reaction to generate a BHET crude product; (2) the BHET crude product is continuously introduced into a hydrolysis kettle, water is continuously introduced, the BHET crude product is fully dissolved, the temperature in the hydrolysis kettle is 60-100 DEG C, and the pressure in the hydrolysis kettle is normal pressure; (3) filtering the fully dissolved BHET crude product, conveying a BHET liquid-phase product obtained by filtering into a purification tower, and carrying out purification treatment, so as to obtain a purified BHET liquid-phase product; and (4) cooling and crystallizing the purified BHET liquid-phase product, filtering and drying to obtain the high-purity BHET. According to the method, the alcoholysis reaction of PET and ethylene glycol is catalyzed by using the high-activity catalyst, the alcoholysis reaction temperature is reduced, the continuous production mode is more met, the produced BHET is purified, metal residues are reduced, and the purity of the BHET is further improved.

The invention belongs to the field of carbon nanomaterials, and provides a method for preparing a carbon quantum dot material doped with elements such as silicon and aluminum by oxidative depolymerization and stripping of coal gangue. Comprising the steps of screening and matching of coal gangue, oxidative depolymerization stripping, centrifugal dialysis membrane filtration and modification, drying and the like, raw materials and all the steps are specifically set, and the particle size or fluorescence performance of fluorescent carbon dots can be specifically selected and set according to selective oxidative depolymerization stripping conditions. The main particle size of the prepared multi-inorganic-element doped carbon quantum dot material is kept within the range of 1.5-2.0 nm, the structure is stable, the optical performance also meets the requirements, and the material can be further modified and is expected to be applied to the fields of photovoltaic equipment, biological imaging, photocatalytic degradation of organic pollutants or sensing and the like.

To provide a depolymerization method that allows efficient removal of a functional layer from a polyester film having a functional layer and enhances polyester recovery efficiency.SOLUTION: A depolymerization method of a polyester film comprising the following steps (I) to (IV): (I) depolymerizing a polyester film containing a functional layer to obtain a crude depolymerization solution A; (II) subjecting the obtained crude depolymerization solution A to specific gravity separation into a purified depolymerization solution X and a crude depolymerization solution B containing free matter; (III) separating free matter from the crude depolymerization solution B to obtain a purified depolymerization solution Y; and (IV) sending the purified depolymerization solution Y to a depolymerization tank.SELECTED DRAWING: Figure 1

The invention belongs to the technical field of emulsion materials, and particularly relates to metal-polyphenol network modified coconut protein composite particles as well as a preparation method and application thereof. The preparation method comprises the following steps: preparing a coconut protein-pectin compound by taking coconut protein and pectin as raw materials, adding a tannic acid solution into the coconut protein-pectin compound, mixing, adding a Fe < 3 + > solution, and mixing to obtain metal-polyphenol network modified coconut protein composite particles; according to the preparation method, tannic acid and the coconut protein-pectin compound are subjected to non-covalent interaction, Fe < 3 + > and phenolic hydroxyl groups on the tannic acid are subjected to coordination reaction, a metal-polyphenol network is formed through cross-linking of Fe-O coordination bonds, and a compact modification layer is constructed on the surface of the coconut protein-pectin compound, so that on one hand, waste coconut protein resources are utilized; on the other hand, the problem that composite particles prepared from pectin and coconut protein are prone to depolymerization is solved, the structural stability is improved, and meanwhile iron and polyphenol are supplemented.

The present invention discloses a method for upgrading polyester materials to dicarboxylic acid esters and ethylene carbonate, and relates to the comprehensive utilization of waste resources and the cascade utilization of raw materials. The method uses multiple types of green ionic liquid catalysts to catalyze the methanolysis reaction of PET, and then dimethyl carbonate captures the generated ethylene glycol in situ, forms a five-membered cyclic ethylene carbonate through nucleophilic cyclization, pulls the reaction equilibrium to move forward, and completely depolymerizes PET waste. The products of the method of the present invention are dimethyl terephthalate and five-membered cyclic ethylene carbonate. The present invention can be used for the depolymerization and upgrading of waste PET materials, and can also be used for other similar polyesters, such as polyethylene succinate, polyethylene adipate and polyethylene 2,5-furan dicarboxylate, which are also suitable for the recovery strategy of the present invention, and the products are the corresponding dimethyl succinate, dimethyl adipate and 2,5-furan dicarboxylate.

The invention discloses a chemical regeneration method of waste polyester, which comprises the following steps: adding waste polyester into ethylene glycol, carrying out a depolymerization reaction, carrying out filtering impurity removal, decoloration, cooling crystallization and separation on the obtained depolymerization reaction liquid to obtain a solid product which is a mixture of BHET and BHET dimer, and directly carrying out a condensation polymerization reaction to prepare regenerated polyester. According to the method disclosed by the invention, the solid impurities filtered and removed when the BHET is purified by adding water are found to be BHET dimers for the first time, and the mixture of the BHET and the BHET dimers is directly used as a raw material to prepare the RPET through polymerization without removing the solid impurities, so that the process is simplified, and the cost is saved. The post-treatment steps are simple, a large amount of water does not need to be added to purify BHET, and the solvent ethylene glycol can be recycled through simple treatment. The steps from waste polyester depolymerization to polymerization for preparation of rPET are few, the process is short, the energy consumption is low, the yield is high, and the method has important significance for high-efficiency recovery of PET and green economic technology popularization.

The invention relates to a method for efficiently hydrolyzing nylon 6 by acid catalysis, and relates to the technical field of hydrolysis of nylon 6, the method comprises the following steps: carrying out hydrolysis reaction on nylon 6, water and an acid catalyst in a closed state to obtain a hydrolysis product; and carrying out purification post-treatment on the hydrolysis product to obtain caprolactam, the reaction pressure of the hydrolysis reaction is controlled in a self-boosting manner; the specific process of the self-boosting mode comprises the step of changing the pressure of the hydrolysis reaction system by adjusting the adding mode of the water. The nylon 6 hydrolysis process provided by the invention is simple, hydrolysis reaction pressure is controlled mainly by a self-boosting control method of a reaction system by controlling a water adding mode, other raw materials do not need to be added, efficient hydrolysis of nylon 6 is realized, and the nylon 6 hydrolysis process has the characteristics of short hydrolysis reaction time, high depolymerization rate and the like, and is suitable for industrial production. The method effectively solves the technical problems of long hydrolysis reaction time and low depolymerization rate in the existing process for catalyzing and hydrolyzing nylon 6 by using an acid method.

The invention relates to a catalytic depolymerization method of a nylon 6 extraction oligomer, and relates to the technical field of polymer depolymerization, a nylon 6 extraction oligomer concentrated solution and a depolymerization catalyst are mixed, heated and subjected to ultrasonic treatment, and a premix is obtained; and performing staged gradient depolymerization on the premix in an inert gas atmosphere to obtain a depolymerization product. The staged gradient depolymerization of the nylon 6 extracted oligomer is realized by controlling the reaction pressure and the reaction temperature in the depolymerization reaction system to be subjected to staged gradient change along with the reaction time, the depolymerization process is simple to operate, other raw materials do not need to be added, the depolymerization rate of the nylon 6 extracted oligomer is increased, and the production cost is reduced. The technical problems of poor catalytic depolymerization effect, tedious operation steps and the like in the conventional catalytic depolymerization process of the nylon 6 extracted oligomer concentrated solution are effectively solved.

The invention relates to the technical field of graphene processing, and particularly discloses a nano graphene powder preparation method which comprises the following steps: weighing a graphite raw material; opening a discharge valve of the feeding cabin, and feeding the graphite raw material into the pressure stabilizing cabin; a graphite raw material is sucked into a first-stage jet mill high-pressure cabin from a pressure stabilizing cabin, first-stage jet milling is conducted, and a first-stage abrasive material is obtained; the first-stage grinding material with the thickness not larger than 10 micrometers is conveyed to a second-stage jet mill high-pressure cabin; processing the first-stage abrasive material by a second-stage jet mill high-pressure cabin to obtain a second-stage abrasive material; the second-stage grinding material with the thickness not larger than 100 nanometers is conveyed to a flow energy depolymerization cabin; the flow energy depolymerization cabin is used for processing the secondary grinding material, and nano graphene powder is obtained through screening; the high-purity graphite raw material is processed through a three-stage gradient processing framework, a negative feedback regulation scheme is introduced in each processing link, the quality of products in different stages is controlled, a progressive processing technology is constructed, and the product rate is greatly increased.

The invention belongs to the technical field of chemical recycling, and particularly relates to a one-way depolymerization, high-purity and high-yield epsilon-CL closed-loop recycling method. According to the method, only trace acetylacetone metal salt is used as a catalyst, the epsilon-caprolactone monomer is recovered in a manner of in-situ catalytic degradation of PCL (polycaprolactone) under the assistance of heating and temperature rise in a low-vacuum environment, the depolymerization efficiency of 100% is realized, and the problems of low depolymerization yield, easiness in carbonization, long time, low purity of recovered products and the like in an existing method are solved. The product obtained by the method disclosed by the invention is pure, does not need complex post-treatment such as secondary purification, water removal and the like, has reaction activity of 100% repolymerization, can be directly used for repolymerization reaction to obtain regenerated PCL, and has the tensile strength of 31.3 MPa and the elongation at break of 831%. According to the method disclosed by the invention, polymer-monomer-polymer closed-loop circulation of PCL is perfectly realized by a mild depolymerization reaction process, and the possibility of industrial depolymerization-polymerization is expected to be realized.

The invention belongs to the field of gene engineering, and particularly relates to a PET hydrolase mutant with high catalytic activity and application thereof. According to the invention, amino acids at the 62nd site, the 65th site, the 66th site, the 71th site, the 154th site, the 156th site, the 177th site, the 183th site, the 184th site, the 209th site, the 213th site, the 214th site and the 215th site in the PES-H1L92F / Q94Y amino acid sequence of the PET hydrolase shown as SEQ ID NO.2 are mutated by utilizing a structural analysis and site-specific mutagenesis technology to obtain various mutants, and the mutants with improved catalytic activity are obtained. The PET hydrolase mutants promote the hydrolysis efficiency of ester bonds in PET so as to improve the degradation capacity of PET plastics, and can be applied to enzymatic depolymerization of PET plastics in life in the future.