A method for removing bisphenol a from recycled material

Abstract

This invention discloses a method for removing bisphenol A from recycled materials, relating to the field of bisphenol A removal technology, comprising the following steps: sorting out recycled polycarbonate materials, washing, drying, and crushing to obtain polycarbonate powder; adding the polycarbonate powder, methanol, and tetrahydrofuran to a reaction vessel, heating and stirring to dissolve, adding a zinc oxide-sodium aluminate catalyst, stirring and reacting at 100-130°C for 30-60 min, cooling, rotary evaporation, washing and filtering, adding deionized water to re-dissolve, heating and mixing, filtering to remove impurities, obtaining a crude bisphenol A solution; adding an iron oxide-cyclodextrin catalyst to the crude bisphenol A solution, stirring and mixing, adding potassium persulfate, reacting at room temperature, obtaining a bisphenol A degradation solution.

Description

Technical Field

[0001] This invention relates to the field of bisphenol A removal technology, specifically a method for removing bisphenol A from recycled materials. Background Technology

[0002] With the advancement of dual-carbon goals, the recycling of renewable materials has become a key focus. Bisphenol A (BPA) aromatic polycarbonates, due to their excellent transparency, toughness, temperature resistance, and large-scale production capabilities, are widely used in optical devices, medical devices, automotive manufacturing, construction, and packaging. However, because BPA degrades in the environment to produce bisphenol A (BPA), which is harmful to human health and the environment, effective BPA removal is necessary. Currently, BPA removal is mainly achieved through physical adsorption, chemical degradation, and biodegradation. However, these methods suffer from limitations such as limited adsorption capacity, difficult regeneration, numerous byproducts, low processing efficiency, and long processing cycles.

[0003] Therefore, it is of great significance to develop an effective method for removing bisphenol A from recycled materials. Summary of the Invention

[0004] The purpose of this invention is to provide a method for removing bisphenol A from recycled materials, thereby solving the problems raised in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A method for removing bisphenol A from recycled materials includes the following steps: S1: Sorting out recycled polycarbonate materials, washing, drying, and crushing to obtain polycarbonate powder; S2: Add polycarbonate powder, methanol and tetrahydrofuran to a reaction vessel, heat and stir to dissolve, add zinc oxide-sodium aluminate catalyst, stir at 100-130℃ for 30-60 min, cool, rotary evaporate, wash and filter, add deionized water to re-dissolve, heat and mix, filter to remove impurities, and obtain crude bisphenol A solution. S3: Add the iron oxide-cyclodextrin catalyst to the crude bisphenol A solution, stir and mix well, add potassium persulfate, and react at room temperature to obtain the bisphenol A degradation solution.

[0006] Furthermore, in step S1, the crushing process is carried out at 15,000-20,000 r / min, and the powder size is 40-200 mesh.

[0007] Further, in step S2, the mass ratio of polycarbonate powder, methanol, tetrahydrofuran, and zinc oxide-sodium aluminate catalyst is 10:(20-40):(60-80):(0.5-1.5).

[0008] Further, in step S2, the preparation method of the zinc oxide-sodium aluminate catalyst is as follows: the precursor powder is added to the reaction vessel, heated to 600-800℃ at 3-5℃, kept at the temperature for 1-2 hours, then placed in methanol, ultrasonically activated, and vacuum dried to obtain the zinc oxide-sodium aluminate composite catalyst.

[0009] Further, the preparation method of the precursor powder is as follows: zinc nitrate hexahydrate and aluminum nitrate nonahydrate are added to an ethanol aqueous solution and stirred to form a zinc-aluminum salt solution. Sodium hydroxide is added to an ethanol aqueous solution and stirred to form an alkaline solution. The zinc-aluminum salt solution and the alkaline solution are simultaneously pumped into a hypergravity reactor and reacted at 60-80℃ for 3-5 hours. The mixture is then spray-dried, cooled to room temperature, and the powder is collected to obtain the precursor powder. During the preparation of the precursor powder, the molar ratio of zinc nitrate hexahydrate, aluminum nitrate nonahydrate, and sodium hydroxide is (1-2):(0.5-1):(0.05-0.15).

[0010] Further, in step S3, the mass ratio of iron oxide-cyclodextrin catalyst, crude bisphenol A solution and potassium persulfate is (1-2):10:(0.5-1).

[0011] Further, in step S3, the preparation method of the iron oxide-cyclodextrin catalyst is as follows: add boron-doped iron oxide and hexafluorotetraic acid-cyclodextrin to deionized water, stir and mix well, add 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide, stir and react at room temperature for 12-24 h to obtain the iron oxide-cyclodextrin catalyst; In the preparation of the iron oxide-cyclodextrin catalyst, the mass ratio of boron amino-doped iron oxide, hexafluorotetraic acid-cyclodextrin, 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide is 10:(10-20):(4-8):(1.2-3.6).

[0012] Further, the preparation method of the boron-doped iron oxide is as follows: add boron-doped iron oxide to an ethanol-hydrochloric acid mixture, mix it by ultrasonication, then add an ethanol solution containing 3-aminopropyltriethoxysilane, stir the reaction for 12-24 hours, perform magnetic separation, wash and dry to obtain boron-doped iron oxide. In the preparation of boron-doped iron oxide, the mass ratio of boron-doped iron oxide to 3-aminopropyltriethoxysilane is 10:(1-2).

[0013] Further, the preparation method of the boron-doped iron oxide is as follows: ferric nitrate and boric acid are added to deionized water, citric acid is added, the mixture is stirred at 50-60℃ for 1-2 hours, the temperature is raised to 70-90℃, the water is evaporated and dehydrated, the temperature is raised to 400-500℃ at a rate of 3-5℃ / min, calcined for 1-2 hours, the impurities are removed by grinding, and the mixture is dried to obtain boron-doped iron oxide; In the preparation of boron-doped iron oxide, the molar ratio of ferric nitrate, boric acid and citric acid is 10:(0.3-0.5):(1-1.5).

[0014] Further, the preparation method of the hexafluorotetraic acid-cyclodextrin is as follows: β-cyclodextrin and hexafluorotetraic acid are added to a reaction vessel, potassium dihydrogen phosphate and deionized water are added, and the reaction is carried out at 100-140℃ for 1.5-3.5h. After washing and drying, hexafluorotetraic acid-cyclodextrin is obtained. In the preparation of hexafluorotetraic acid-cyclodextrin, the molar ratio of β-cyclodextrin, hexafluorotetraic acid, and potassium dihydrogen phosphate is 1:(3-5):(0.1-0.2).

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention introduces zinc oxide-sodium aluminate as a catalyst for the degradation of polycarbonate. First, a zinc oxide-sodium aluminate composite catalyst is prepared using a centrifugal method, resulting in a uniform particle size distribution, good catalytic activity and stability, and ease of industrial production. Second, sodium aluminate is a solid base catalyst; its combination with zinc oxide increases the active sites and basicity of the catalyst, thereby increasing the rate of polycarbonate degradation and effectively improving the purity of bisphenol A generated from polycarbonate degradation while reducing byproducts.

[0016] 2. This invention introduces boron-doped iron oxide with amino groups. First, by introducing boron into iron oxide through in-situ doping, not only can the continuous generation of free radicals be maintained, improving the catalytic activity of iron oxide for bisphenol A, but it can also form a magnetic phase in the iron oxide, which is beneficial for catalyst recovery. Second, the boron-doped iron oxide is modified with 3-aminopropyltriethoxysilane. On the one hand, this improves the dispersibility of the boron-doped iron oxide in the crude bisphenol A solution; on the other hand, the amino groups on it can react with the carboxyl groups in hexafluorotetraic acid-cyclodextrin, providing sufficient active sites for cyclodextrin-coupled iron oxide.

[0017] 3. This invention introduces hexafluorotetraic acid-cyclodextrin. On one hand, hexafluorotetraic acid can act as a cross-linking agent, enabling cyclodextrin to fully cross-link, giving it good chemical stability and hydrophobicity, preventing the detachment of bisphenol A adsorbed by cyclodextrin, thereby improving the efficiency of bisphenol A degradation by the iron oxide-cyclodextrin catalyst. On the other hand, cyclodextrin can specifically adsorb bisphenol A in crude bisphenol A solution, promoting a Fenton-like reaction in boron-doped iron oxide, thereby improving the catalytic efficiency of the iron oxide-cyclodextrin catalyst. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] In the following examples, the CAS number of tetrahydrofuran is 109-99-9; the CAS number of zinc nitrate hexahydrate is 10196-18-6; the CAS number of aluminum nitrate nonahydrate is 7784-27-2; the CAS number of boric acid is 10043-35-3; the CAS number of citric acid is 77-92-9; the CAS number of 3-aminopropyltriethoxysilane is 919-30-2; the CAS number of hexafluorotetraic acid is 3016-76-0; the CAS number of 1-ethyl-(3-dimethylaminopropyl)carbodiimide is 1892-57-5; the CAS number of N-hydroxysuccinimide is 6066-82-6; and the CAS number of potassium persulfate is 70693-62-8.

[0020] Example 1: A method for removing bisphenol A from recycled materials: Step 1: Preparation of crude bisphenol A solution: S1: The recycled polycarbonate material is sorted out, washed, dried at 60℃ for 12h, and crushed into 200-mesh powder at 15000r / min to obtain polycarbonate powder; S2: Add 1 part zinc nitrate hexahydrate and 0.5 parts aluminum nitrate nonahydrate to an ethanol aqueous solution, stir and mix to form a zinc-aluminum salt solution, add 0.05 parts sodium hydroxide to an ethanol aqueous solution, stir and mix to form an alkaline solution, pump the zinc-aluminum salt solution and the alkaline solution into a hypergravity reactor at the same time, react at 60°C for 3 hours, spray dry, cool to room temperature, collect the powder, and obtain the precursor powder; S3: Add the precursor powder to the reaction vessel, heat it to 600℃ at 3℃, keep it at 600℃ for 1h, then place it in methanol, ultrasonically activate it for 3h, and vacuum dry it at 70℃ to obtain the zinc oxide-sodium aluminate composite catalyst. S4: Add 10 parts of polycarbonate powder, 20 parts of methanol and 60 parts of tetrahydrofuran to the reaction vessel, heat and stir to dissolve, add 0.5 parts of zinc oxide-sodium aluminate catalyst, stir at 100℃ for 30 min, cool, rotary evaporate, wash and filter, add deionized water to redissolve, heat and mix, filter to remove impurities, and obtain a crude bisphenol A solution. Step 2: Remove Bisphenol A: S1: Add 10 parts of ferric nitrate and 0.3 parts of boric acid to deionized water, add 1 part of citric acid, stir and react at 50°C for 2 hours, raise the temperature to 70°C, evaporate and dehydrate, and obtain boron-doped iron oxide by raising the temperature to 400°C at a rate of 3°C / min, calcining for 1 hour, grinding to remove impurities, and drying. S2: Add 10 parts of boron-doped iron oxide to an ethanol-hydrochloric acid mixture, mix by ultrasonication, then add an ethanol solution containing 1 part of 3-aminopropyltriethoxysilane, stir for 12 hours, magnetically separate, wash and dry to obtain boron-doped iron oxide with amino groups. S3: Add 1 part β-cyclodextrin and 3 parts hexafluorotetraic acid to the reaction vessel, add 0.1 part potassium dihydrogen phosphate and deionized water, react at 100℃ for 1.5 h, wash and dry to obtain hexafluorotetraic acid-cyclodextrin; S4: Add 10 parts of boron-doped iron oxide and 10 parts of hexafluorotetraic acid-cyclodextrin to deionized water, stir and mix well, add 4 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 1.2 parts of N-hydroxysuccinimide, stir and react at room temperature for 12 h to obtain iron oxide-cyclodextrin catalyst. S5: Add 1 part of iron oxide-cyclodextrin catalyst to 10 parts of crude bisphenol A solution, stir and mix well, add 0.5 parts of potassium persulfate, react at room temperature to obtain bisphenol A degradation solution.

[0021] Example 2: A method for removing bisphenol A from recycled materials: Step 1: Preparation of crude bisphenol A solution: S1: The recycled polycarbonate material is sorted out, washed, dried at 60℃ for 12h, and crushed into 140-mesh powder at 17500r / min to obtain polycarbonate powder; S2: Add 1.5 parts of zinc nitrate hexahydrate and 0.75 parts of aluminum nitrate nonahydrate to an ethanol-water solution, stir and mix to form a zinc-aluminum salt solution, add 0.1 parts of sodium hydroxide to an ethanol-water solution, stir and mix to form an alkaline solution, pump the zinc-aluminum salt solution and the alkaline solution into a hypergravity reactor at the same time, react at 60°C for 3 hours, spray dry, cool to room temperature, collect the powder, and obtain the precursor powder; S3: Add the precursor powder to the reaction vessel, heat it to 700℃ at 4℃, keep it at 700℃ for 1.5h, then place it in methanol, ultrasonically activate it for 3h, and vacuum dry it at 70℃ to obtain the zinc oxide-sodium aluminate composite catalyst. S4: Add 10 parts of polycarbonate powder, 30 parts of methanol and 70 parts of tetrahydrofuran to a reaction vessel, heat and stir to dissolve, add 1 part of zinc oxide-sodium aluminate catalyst, stir at 120℃ for 45 min, cool, rotary evaporate, wash and filter, add deionized water to redissolve, heat and mix, filter to remove impurities, and obtain a crude bisphenol A solution. Step 2: Remove Bisphenol A: S1: Add 10 parts of ferric nitrate and 0.3 parts of boric acid to deionized water, add 1 part of citric acid, stir and react at 50°C for 2 hours, raise the temperature to 70°C, evaporate and dehydrate, and obtain boron-doped iron oxide by raising the temperature to 400°C at a rate of 3°C / min, calcining for 1 hour, grinding to remove impurities, and drying. S2: Add 10 parts of boron-doped iron oxide to an ethanol-hydrochloric acid mixture, mix by ultrasonication, then add an ethanol solution containing 1 part of 3-aminopropyltriethoxysilane, stir for 12 hours, magnetically separate, wash and dry to obtain boron-doped iron oxide with amino groups. S3: Add 1 part β-cyclodextrin and 3 parts hexafluorotetraic acid to the reaction vessel, add 0.1 part potassium dihydrogen phosphate and deionized water, react at 100℃ for 1.5 h, wash and dry to obtain hexafluorotetraic acid-cyclodextrin; S4: Add 10 parts of boron-doped iron oxide and 10 parts of hexafluorotetraic acid-cyclodextrin to deionized water, stir and mix well, add 4 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 1.2 parts of N-hydroxysuccinimide, stir and react at room temperature for 12 h to obtain iron oxide-cyclodextrin catalyst. S5: Add 1 part of iron oxide-cyclodextrin catalyst to 10 parts of crude bisphenol A solution, stir and mix well, add 0.5 parts of potassium persulfate, react at room temperature to obtain bisphenol A degradation solution.

[0022] Example 3: A method for removing bisphenol A from recycled materials: Step 1: Prepare a crude bisphenol A solution: S1: The recycled polycarbonate material is sorted out, washed, dried at 60℃ for 12h, and crushed into 80-mesh powder at 20000r / min to obtain polycarbonate powder; S2: Add 2 parts of zinc nitrate hexahydrate and 1 part of aluminum nitrate nonahydrate to an ethanol aqueous solution, stir and mix to form a zinc-aluminum salt solution, add 0.15 parts of sodium hydroxide to an ethanol aqueous solution, stir and mix to form an alkaline solution, pump the zinc-aluminum salt solution and the alkaline solution into a hypergravity reactor at the same time, react at 60°C for 3 hours, spray dry, cool to room temperature, collect the powder, and obtain the precursor powder; S3: Add the precursor powder to the reaction vessel, heat it to 800°C at 5°C, keep it at 800°C for 2 hours, then place it in methanol, ultrasonically activate it for 3 hours, and vacuum dry it at 70°C to obtain the zinc oxide-sodium aluminate composite catalyst. S4: Add 10 parts of polycarbonate powder, 40 parts of methanol and 80 parts of tetrahydrofuran to the reaction vessel, heat and stir to dissolve, add 1.5 parts of zinc oxide-sodium aluminate catalyst, stir at 130℃ for 60 min, cool, rotary evaporate, wash and filter, add deionized water to redissolve, heat and mix, filter to remove impurities, and obtain a crude bisphenol A solution. Step 2: Remove Bisphenol A: S1: Add 10 parts of ferric nitrate and 0.3 parts of boric acid to deionized water, add 1 part of citric acid, stir and react at 50°C for 2 hours, raise the temperature to 70°C, evaporate and dehydrate, and obtain boron-doped iron oxide by raising the temperature to 400°C at a rate of 3°C / min, calcining for 1 hour, grinding to remove impurities, and drying. S2: Add 10 parts of boron-doped iron oxide to an ethanol-hydrochloric acid mixture, mix by ultrasonication, then add an ethanol solution containing 1 part of 3-aminopropyltriethoxysilane, stir for 12 hours, magnetically separate, wash and dry to obtain boron-doped iron oxide with amino groups. S3: Add 1 part β-cyclodextrin and 3 parts hexafluorotetraic acid to the reaction vessel, add 0.1 part potassium dihydrogen phosphate and deionized water, react at 100℃ for 1.5 h, wash and dry to obtain hexafluorotetraic acid-cyclodextrin; S4: Add 10 parts of boron-doped iron oxide and 10 parts of hexafluorotetraic acid-cyclodextrin to deionized water, stir and mix well, add 4 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 1.2 parts of N-hydroxysuccinimide, stir and react at room temperature for 12 h to obtain iron oxide-cyclodextrin catalyst. S5: Add 1 part of iron oxide-cyclodextrin catalyst to 10 parts of crude bisphenol A solution, stir and mix well, add 0.5 parts of potassium persulfate, react at room temperature to obtain bisphenol A degradation solution.

[0023] Example 4: A method for removing bisphenol A from recycled materials: Step 1: Preparation of crude bisphenol A solution: S1: The recycled polycarbonate material is sorted out, washed, dried at 60℃ for 12h, and crushed into 80-mesh powder at 20000r / min to obtain polycarbonate powder; S2: Add 2 parts of zinc nitrate hexahydrate and 1 part of aluminum nitrate nonahydrate to an ethanol aqueous solution, stir and mix to form a zinc-aluminum salt solution, add 0.15 parts of sodium hydroxide to an ethanol aqueous solution, stir and mix to form an alkaline solution, pump the zinc-aluminum salt solution and the alkaline solution into a hypergravity reactor at the same time, react at 60°C for 3 hours, spray dry, cool to room temperature, collect the powder, and obtain the precursor powder; S3: Add the precursor powder to the reaction vessel, heat it to 800°C at 5°C, keep it at 800°C for 2 hours, then place it in methanol, ultrasonically activate it for 3 hours, and vacuum dry it at 70°C to obtain the zinc oxide-sodium aluminate composite catalyst. S4: Add 10 parts of polycarbonate powder, 40 parts of methanol and 80 parts of tetrahydrofuran to the reaction vessel, heat and stir to dissolve, add 1.5 parts of zinc oxide-sodium aluminate catalyst, stir at 130℃ for 60 min, cool, rotary evaporate, wash and filter, add deionized water to redissolve, heat and mix, filter to remove impurities, and obtain a crude bisphenol A solution. Step 2: Remove Bisphenol A: S1: Add 10 parts of ferric nitrate and 0.4 parts of boric acid to deionized water, add 1.3 parts of citric acid, stir and react at 55°C for 1.5 h, raise the temperature to 80°C, evaporate and dehydrate, and obtain boron-doped iron oxide by raising the temperature to 450°C at a rate of 4°C / min and calcining for 1.5 h, grinding to remove impurities, and drying. S2: Add 10 parts of boron-doped iron oxide to an ethanol-hydrochloric acid mixture, mix by ultrasonication, then add an ethanol solution containing 1.5 parts of 3-aminopropyltriethoxysilane, stir for 18 hours, magnetically separate, wash and dry to obtain boron-doped iron oxide with amino groups. S3: Add 1 part β-cyclodextrin and 3 parts hexafluorotetraic acid to the reaction vessel, add 0.1 part potassium dihydrogen phosphate and deionized water, react at 100℃ for 1.5 h, wash and dry to obtain hexafluorotetraic acid-cyclodextrin; S4: Add 10 parts of boron-doped iron oxide and 10 parts of hexafluorotetraic acid-cyclodextrin to deionized water, stir and mix well, add 4 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 1.2 parts of N-hydroxysuccinimide, stir and react at room temperature for 12 h to obtain iron oxide-cyclodextrin catalyst. S5: Add 1 part of iron oxide-cyclodextrin catalyst to 10 parts of crude bisphenol A solution, stir and mix well, add 0.5 parts of potassium persulfate, react at room temperature to obtain bisphenol A degradation solution.

[0024] Example 5: A method for removing bisphenol A from recycled materials: Step 1: Prepare a crude bisphenol A solution: S1: The recycled polycarbonate material is sorted out, washed, dried at 60℃ for 12h, and crushed into 80-mesh powder at 20000r / min to obtain polycarbonate powder; S2: Add 2 parts of zinc nitrate hexahydrate and 1 part of aluminum nitrate nonahydrate to an ethanol aqueous solution, stir and mix to form a zinc-aluminum salt solution, add 0.15 parts of sodium hydroxide to an ethanol aqueous solution, stir and mix to form an alkaline solution, pump the zinc-aluminum salt solution and the alkaline solution into a hypergravity reactor at the same time, react at 60°C for 3 hours, spray dry, cool to room temperature, collect the powder, and obtain the precursor powder; S3: Add the precursor powder to the reaction vessel, heat it to 800°C at 5°C, keep it at 800°C for 2 hours, then place it in methanol, ultrasonically activate it for 3 hours, and vacuum dry it at 70°C to obtain the zinc oxide-sodium aluminate composite catalyst. S4: Add 10 parts of polycarbonate powder, 40 parts of methanol and 80 parts of tetrahydrofuran to the reaction vessel, heat and stir to dissolve, add 1.5 parts of zinc oxide-sodium aluminate catalyst, stir at 130℃ for 60 min, cool, rotary evaporate, wash and filter, add deionized water to redissolve, heat and mix, filter to remove impurities, and obtain a crude bisphenol A solution. Step 2: Remove Bisphenol A: S1: Add 10 parts of ferric nitrate and 0.5 parts of boric acid to deionized water, add 1.5 parts of citric acid, stir and react at 60°C for 2 hours, raise the temperature to 90°C, evaporate and dehydrate, and obtain boron-doped iron oxide by raising the temperature to 500°C at a rate of 5°C / min, calcining for 2 hours, grinding to remove impurities, and drying. S2: Add 10 parts of boron-doped iron oxide to an ethanol-hydrochloric acid mixture, mix by ultrasonication, then add an ethanol solution containing 2 parts of 3-aminopropyltriethoxysilane, stir for 24 hours, magnetically separate, wash and dry to obtain boron-doped iron oxide with amino groups. S3: Add 1 part β-cyclodextrin and 3 parts hexafluorotetraic acid to the reaction vessel, add 0.1 part potassium dihydrogen phosphate and deionized water, react at 100℃ for 1.5 h, wash and dry to obtain hexafluorotetraic acid-cyclodextrin; S4: Add 10 parts of boron-doped iron oxide and 10 parts of hexafluorotetraic acid-cyclodextrin to deionized water, stir and mix well, add 4 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 1.2 parts of N-hydroxysuccinimide, stir and react at room temperature for 12 h to obtain iron oxide-cyclodextrin catalyst. S5: Add 1 part of iron oxide-cyclodextrin catalyst to 10 parts of crude bisphenol A solution, stir and mix well, add 0.5 parts of potassium persulfate, react at room temperature to obtain bisphenol A degradation solution.

[0025] Example 6: A method for removing bisphenol A from recycled materials: Step 1: Prepare a crude bisphenol A solution: S1: The recycled polycarbonate material is sorted out, washed, dried at 60℃ for 12h, and crushed into 80-mesh powder at 20000r / min to obtain polycarbonate powder; S2: Add 2 parts of zinc nitrate hexahydrate and 1 part of aluminum nitrate nonahydrate to an ethanol aqueous solution, stir and mix to form a zinc-aluminum salt solution, add 0.15 parts of sodium hydroxide to an ethanol aqueous solution, stir and mix to form an alkaline solution, pump the zinc-aluminum salt solution and the alkaline solution into a hypergravity reactor at the same time, react at 60°C for 3 hours, spray dry, cool to room temperature, collect the powder, and obtain the precursor powder; S3: Add the precursor powder to the reaction vessel, heat it to 800°C at 5°C, keep it at 800°C for 2 hours, then place it in methanol, ultrasonically activate it for 3 hours, and vacuum dry it at 70°C to obtain the zinc oxide-sodium aluminate composite catalyst. S4: Add 10 parts of polycarbonate powder, 40 parts of methanol and 80 parts of tetrahydrofuran to the reaction vessel, heat and stir to dissolve, add 1.5 parts of zinc oxide-sodium aluminate catalyst, stir at 130℃ for 60 min, cool, rotary evaporate, wash and filter, add deionized water to redissolve, heat and mix, filter to remove impurities, and obtain a crude bisphenol A solution. Step 2: Remove Bisphenol A: S1: Add 10 parts of ferric nitrate and 0.5 parts of boric acid to deionized water, add 1.5 parts of citric acid, stir and react at 60°C for 2 hours, raise the temperature to 90°C, evaporate and dehydrate, and obtain boron-doped iron oxide by raising the temperature to 500°C at a rate of 5°C / min, calcining for 2 hours, grinding to remove impurities, and drying. S2: Add 10 parts of boron-doped iron oxide to an ethanol-hydrochloric acid mixture, mix by ultrasonication, then add an ethanol solution containing 2 parts of 3-aminopropyltriethoxysilane, stir for 24 hours, magnetically separate, wash and dry to obtain boron-doped iron oxide with amino groups. S3: Add 1 part β-cyclodextrin and 4 parts hexafluorotetraic acid to the reaction vessel, add 0.15 parts potassium dihydrogen phosphate and deionized water, react at 120℃ for 2.5 h, wash and dry to obtain hexafluorotetraic acid-cyclodextrin; S4: Add 10 parts of boron-doped iron oxide and 15 parts of hexafluorotetraic acid-cyclodextrin to deionized water, stir and mix well, add 6 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 2.4 parts of N-hydroxysuccinimide, stir and react at room temperature for 18 h to obtain iron oxide-cyclodextrin catalyst. S5: Add 1.5 parts of iron oxide-cyclodextrin catalyst to 10 parts of crude bisphenol A solution, stir and mix well, add 0.75 parts of potassium persulfate, and react at room temperature to obtain bisphenol A degradation.

[0026] Example 7: A method for removing bisphenol A from recycled materials: Step 1: Preparation of crude bisphenol A solution: S1: The recycled polycarbonate material is sorted out, washed, dried at 60℃ for 12h, and crushed into 80-mesh powder at 20000r / min to obtain polycarbonate powder; S2: Add 2 parts of zinc nitrate hexahydrate and 1 part of aluminum nitrate nonahydrate to an ethanol aqueous solution, stir and mix to form a zinc-aluminum salt solution, add 0.15 parts of sodium hydroxide to an ethanol aqueous solution, stir and mix to form an alkaline solution, pump the zinc-aluminum salt solution and the alkaline solution into a hypergravity reactor at the same time, react at 60°C for 3 hours, spray dry, cool to room temperature, collect the powder, and obtain the precursor powder; S3: Add the precursor powder to the reaction vessel, heat it to 800°C at 5°C, keep it at 800°C for 2 hours, then place it in methanol, ultrasonically activate it for 3 hours, and vacuum dry it at 70°C to obtain the zinc oxide-sodium aluminate composite catalyst. S4: Add 10 parts of polycarbonate powder, 40 parts of methanol and 80 parts of tetrahydrofuran to the reaction vessel, heat and stir to dissolve, add 1.5 parts of zinc oxide-sodium aluminate catalyst, stir at 130℃ for 60 min, cool, rotary evaporate, wash and filter, add deionized water to redissolve, heat and mix, filter to remove impurities, and obtain a crude bisphenol A solution. Step 2: Remove Bisphenol A: S1: Add 10 parts of ferric nitrate and 0.5 parts of boric acid to deionized water, add 1.5 parts of citric acid, stir and react at 60°C for 2 hours, raise the temperature to 90°C, evaporate and dehydrate, and obtain boron-doped iron oxide by raising the temperature to 500°C at a rate of 5°C / min, calcining for 2 hours, grinding to remove impurities, and drying. S2: Add 10 parts of boron-doped iron oxide to an ethanol-hydrochloric acid mixture, mix by ultrasonication, then add an ethanol solution containing 2 parts of 3-aminopropyltriethoxysilane, stir for 24 hours, magnetically separate, wash and dry to obtain boron-doped iron oxide with amino groups. S3: Add 1 part β-cyclodextrin and 5 parts hexafluorotetraic acid to the reaction vessel, add 0.2 parts potassium dihydrogen phosphate and deionized water, react at 140℃ for 3.5 h, wash and dry to obtain hexafluorotetraic acid-cyclodextrin; S4: Add 10 parts of boron-doped iron oxide and 20 parts of hexafluorotetraic acid-cyclodextrin to deionized water, stir and mix well, add 8 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 3.6 parts of N-hydroxysuccinimide, stir and react at room temperature for 24 h to obtain iron oxide-cyclodextrin catalyst. S5: Add 2 parts of iron oxide-cyclodextrin catalyst to 10 parts of crude bisphenol A solution, stir and mix well, add 1 part of potassium persulfate, and react at room temperature to obtain bisphenol A degradation.

[0027] Comparative Example 1: A method for removing bisphenol A from recycled materials: Step 1: Preparation of crude bisphenol A solution: S1: The recycled polycarbonate material is sorted out, washed, dried at 60℃ for 12h, and crushed into 80-mesh powder at 20000r / min to obtain polycarbonate powder; S2: Add 10 parts of polycarbonate powder, 40 parts of methanol and 80 parts of tetrahydrofuran to a reaction vessel, heat and stir to dissolve, add 1.5 parts of zinc oxide catalyst, stir at 130℃ for 60 min, cool, rotary evaporate, wash and filter, add deionized water to re-dissolve, heat and mix, filter to remove impurities, and obtain a crude bisphenol A solution. The remaining steps are the same as in Example 7.

[0028] Comparative Example 2: A method for removing bisphenol A from recycled materials: Step 2: Removal of bisphenol A: S1: Add 10 parts of ferric nitrate and 0.5 parts of boric acid to deionized water, add 1.5 parts of citric acid, stir and react at 60°C for 2 hours, raise the temperature to 90°C, evaporate and dehydrate, and obtain boron-doped iron oxide by raising the temperature to 500°C at a rate of 5°C / min, calcining for 2 hours, grinding to remove impurities, and drying. S2: Add 1 part β-cyclodextrin and 5 parts hexafluorotetraic acid to the reaction vessel, add 0.2 parts potassium dihydrogen phosphate and deionized water, react at 140℃ for 3.5 h, wash and dry to obtain hexafluorotetraic acid-cyclodextrin; S3: Add 10 parts of boron-doped iron oxide and 20 parts of hexafluorotetraic acid-cyclodextrin to deionized water, stir and mix well, and ball mill to obtain iron oxide-cyclodextrin catalyst. S4: Add 2 parts of iron oxide-cyclodextrin catalyst to 10 parts of crude bisphenol A solution, stir and mix well, add 1 part of potassium persulfate, react at room temperature to obtain bisphenol A degradation solution; The remaining steps are the same as in Example 7.

[0029] Comparative Example 3: A method for removing bisphenol A from recycled materials: Step 2: Removal of bisphenol A: S1: Add 10 parts of ferric nitrate and 0.5 parts of boric acid to deionized water, add 1.5 parts of citric acid, stir and react at 60°C for 2 hours, raise the temperature to 90°C, evaporate and dehydrate, and obtain boron-doped iron oxide by raising the temperature to 500°C at a rate of 5°C / min, calcining for 2 hours, grinding to remove impurities, and drying. S2: Add 10 parts of boron-doped iron oxide to an ethanol-hydrochloric acid mixture, mix by ultrasonication, then add an ethanol solution containing 2 parts of 3-aminopropyltriethoxysilane, stir for 24 hours, magnetically separate, wash and dry to obtain boron-doped iron oxide with amino groups. S3: Add 1 part β-cyclodextrin and 5 parts toluene diisocyanate to a reaction vessel, add 0.2 parts potassium dihydrogen phosphate and deionized water, react at 140℃ for 3.5 h, wash and dry to obtain toluene diisocyanate-cyclodextrin; S4: Add 10 parts of boron-doped iron oxide and 20 parts of toluene diisocyanate-cyclodextrin to deionized water, stir and mix well, and ball mill to obtain iron oxide-cyclodextrin catalyst. S5: Add 2 parts of iron oxide-cyclodextrin catalyst to 10 parts of crude bisphenol A solution, stir and mix well, add 1 part of potassium persulfate, react at room temperature to obtain bisphenol A degradation solution. The remaining steps are the same as in Example 7.

[0030] Test samples: Take the crude bisphenol A solution and bisphenol A degradation solution samples prepared in the above examples and comparative examples, add ethanol to the bisphenol A degradation solution to terminate the reaction, filter, collect the filtrate, and use high performance liquid chromatography to detect the concentration of bisphenol A in the two samples respectively, and calculate the residual rate of bisphenol A.

[0031] The experimental results are shown in Table 1 below.

[0032] Table 1 Performance test data for removing bisphenol A from recycled materials

[0033] Conclusion: By optimizing the chemical treatment process and catalyst ratio, bisphenol A in recycled polycarbonate materials can be effectively removed.

[0034] In Comparative Example 1, zinc oxide was used as the catalyst only during the degradation of polycarbonate. This reduced the active sites and basicity of the catalyst, which not only decreased the catalytic efficiency of the catalyst but also reduced the purity of bisphenol A and increased the amount of byproducts, which is not conducive to the effective removal of bisphenol A in subsequent processes.

[0035] In Comparative Example 2, the lack of amination modification of boron-doped iron oxide not only reduced the dispersibility of iron oxide in the crude bisphenol A solution but also prevented it from chemically coupling with cyclodextrin, thus reducing the efficiency of the synergistic catalytic effect and increasing the residual amount of bisphenol A in the bisphenol A degradation solution.

[0036] In Comparative Example 3, toluene diisocyanate was used as a crosslinking agent for cyclodextrin. Due to the lack of carboxyl functional groups on it, it could not chemically couple with boron aminodoped iron oxide, which reduced the catalytic efficiency of the catalyst and thus led to an increase in bisphenol A residue.

[0037] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A method for removing bisphenol A from recycled materials, characterized in that: Includes the following steps: S1: Sorting out recycled polycarbonate materials, washing, drying, and crushing to obtain polycarbonate powder; S2: Add polycarbonate powder, methanol and tetrahydrofuran to a reaction vessel, heat and stir to dissolve, add zinc oxide-sodium aluminate catalyst, stir at 100-130℃ for 30-60 min, cool, rotary evaporate, wash and filter, add deionized water to re-dissolve, heat and mix, filter to remove impurities, and obtain crude bisphenol A solution. S3: Add the iron oxide-cyclodextrin catalyst to the crude bisphenol A solution, stir and mix well, add potassium persulfate, and react at room temperature to obtain the bisphenol A degradation solution.

2. The method for removing bisphenol A from recycled materials according to claim 1, characterized in that: In step S1, the crushing process is carried out at 15,000-20,000 r / min and the powder size is 40-200 mesh.

3. The method for removing bisphenol A from recycled materials according to claim 1, characterized in that: In step S2, the mass ratio of polycarbonate powder, methanol, tetrahydrofuran, and zinc oxide-sodium aluminate catalyst is 10:(20-40):(60-80):(0.5-1.5).

4. The method for removing bisphenol A from recycled materials according to claim 1, characterized in that: In step S2, the preparation method of the zinc oxide-sodium aluminate catalyst is as follows: the precursor powder is added to the reaction vessel, heated to 600-800℃ at 3-5℃, kept at the temperature for 1-2 hours, and then placed in methanol, ultrasonically activated, and vacuum dried to obtain the zinc oxide-sodium aluminate composite catalyst.

5. The method for removing bisphenol A from recycled materials according to claim 4, characterized in that: The precursor powder is prepared as follows: zinc nitrate hexahydrate and aluminum nitrate nonahydrate are added to an ethanol aqueous solution and stirred to form a zinc-aluminum salt solution. Sodium hydroxide is added to the ethanol aqueous solution and stirred to form an alkaline solution. The zinc-aluminum salt solution and the alkaline solution are simultaneously pumped into a hypergravity reactor and reacted at 60-80℃ for 3-5 hours. The mixture is then spray-dried, cooled to room temperature, and the powder is collected to obtain the precursor powder. During the preparation of the precursor powder, the molar ratio of zinc nitrate hexahydrate, aluminum nitrate nonahydrate, and sodium hydroxide is (1-2):(0.5-1):(0.05-0.15).

6. The method for removing bisphenol A from recycled materials according to claim 1, characterized in that: In step S3, the mass ratio of iron oxide-cyclodextrin catalyst, crude bisphenol A solution and potassium persulfate is (1-2):10:(0.5-1).

7. The method for removing bisphenol A from recycled materials according to claim 1, characterized in that: In step S3, the preparation method of the iron oxide-cyclodextrin catalyst is as follows: add boron-doped iron oxide and hexafluorotetraic acid-cyclodextrin to deionized water, stir and mix well, add 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide, stir and react at room temperature for 12-24 h to obtain the iron oxide-cyclodextrin catalyst. In the preparation of the iron oxide-cyclodextrin catalyst, the mass ratio of boron amino-doped iron oxide, hexafluorotetraic acid-cyclodextrin, 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide is 10:(10-20):(4-8):(1.2-3.6).

8. The method for removing bisphenol A from recycled materials according to claim 7, characterized in that: The preparation method of the boron-doped iron oxide is as follows: add boron-doped iron oxide to an ethanol-hydrochloric acid mixture, mix it by ultrasonication, then add an ethanol solution containing 3-aminopropyltriethoxysilane, stir and react for 12-24 hours, perform magnetic separation, wash and dry to obtain boron-doped iron oxide. In the preparation of boron-doped iron oxide, the mass ratio of boron-doped iron oxide to 3-aminopropyltriethoxysilane is 10:(1-2).

9. A method for removing bisphenol A from recycled materials according to claim 8, characterized in that: The preparation method of the boron-doped iron oxide is as follows: ferric nitrate and boric acid are added to deionized water, citric acid is added, the mixture is stirred at 50-60℃ for 1-2 hours, the temperature is raised to 70-90℃, the water is evaporated and dehydrated, and the mixture is calcined at 400-500℃ at a rate of 3-5℃ / min for 1-2 hours, ground to remove impurities, and dried to obtain boron-doped iron oxide. In the preparation of boron-doped iron oxide, the molar ratio of ferric nitrate, boric acid and citric acid is 10:(0.3-0.5):(1-1.5).

10. A method for removing bisphenol A from recycled materials according to claim 7, characterized in that: The preparation method of the hexafluorotetraic acid-cyclodextrin is as follows: β-cyclodextrin and hexafluorotetraic acid are added to a reaction vessel, potassium dihydrogen phosphate and deionized water are added, and the reaction is carried out at 100-140℃ for 1.5-3.5h. After washing and drying, hexafluorotetraic acid-cyclodextrin is obtained. In the preparation of hexafluorotetraic acid-cyclodextrin, the molar ratio of β-cyclodextrin, hexafluorotetraic acid, and potassium dihydrogen phosphate is 1:(3-5):(0.1-0.2).

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