Method for removing polyethylene glycol in water

Abstract

The invention provides a method for removing polyethylene glycol in water, and the method specifically comprises the following steps: S1, adding a hydrogen peroxide solution into a solution containing polyethylene glycol, reacting for a certain time, adding a sodium hydroxide solution, and adjusting the pH value of the solution; and S2, filtering the solution obtained in the step S1 by adopting a polyguanidine grafted two-component hollow electrostatic spinning fiber membrane so as to remove polyethylene glycol in water. According to the prepared two-component hollow electrostatic spinning fiber membrane, carboxymethyl chitosan / berberine hydrochloride serves as a shell layer, a porous RGO membrane serves as a core layer, berberine hydrochloride in the shell layer releases quaternary ammonium salt cations to adsorb carboxylate ions so that polyethylene glycol can be removed, PVP in the core layer is removed so that a porous structure can be constructed in the RGO fiber membrane, and the two-component hollow electrostatic spinning fiber membrane is prepared. And the hollow fiber membrane has a relatively high specific surface area, so that more active sites are provided for ion adsorption, and therefore, the adsorption efficiency is improved.

Description

Technical Field

[0001] The invention relates to the field of environmental protection, and in particular to a method for removing polyethylene glycol from water. Background Art

[0002] In recent years, with the growing demand for clean energy, the photovoltaic industry has experienced rapid development. As a sustainable clean energy, solar energy accounts for an increasing proportion in the global energy structure. The manufacture of photovoltaic cells is a key link in achieving efficient use of solar energy, and in the process of photovoltaic cell manufacturing, the cutting of silicon wafers is an important step. Photovoltaic cutting fluid plays a vital role in the silicon wafer cutting process. It is mainly used to cool and lubricate cutting tools, while taking away impurities such as silicon chips generated during the cutting process to ensure the accuracy and efficiency of cutting. Polyethylene glycol (PEG) is a common polymer that is widely used in photovoltaic cutting fluid due to its good water solubility, lubricity and chemical stability. In the cutting fluid, polyethylene glycol helps to improve the quality and efficiency of cutting and reduce the wear of cutting tools. However, in the treatment process of the cutting fluid after use, the presence of polyethylene glycol makes it difficult to recycle and reuse the cutting fluid. Because polyethylene glycol affects the recovery efficiency of other components in the cutting fluid, and if the cutting fluid containing polyethylene glycol is directly discharged, it will cause pollution to the environment. Summary of the invention

[0003] Technical problem to be solved: The purpose of the present invention is to provide a method for removing polyethylene glycol from water, which oxidizes the primary hydroxyl groups in polyethylene glycol into carboxyl groups, and ionizes the carboxyl groups into carboxylate ions by adjusting the pH of the solution, and finally removes the polyethylene glycol through the adsorption effect of a polyguanidine-grafted two-component hollow electrospun fiber membrane.

[0004] Technical solution: A method for removing polyethylene glycol from water, the method comprising the following steps: S1. Add hydrogen peroxide solution to the solution containing polyethylene glycol, add sodium hydroxide solution after a certain reaction time, and adjust the pH of the solution to 7-8; S2. Filter the solution obtained in S1 using a polyguanidine-grafted two-component hollow electrospun fiber membrane to remove polyethylene glycol from the water; Among them, the polyguanidine grafted two-component hollow electrospun fiber membrane in step S2 has carboxymethyl chitosan / berberine hydrochloride as the shell layer and a porous RGO membrane as the core layer. The core layer is removed by removing PVP to construct a porous structure in the RGO fiber membrane. The thickness of the polyguanidine grafted two-component hollow electrospun fiber membrane is 15 to 25 μm, and the porosity is 80 to 90%. Preferably, the mass fraction of the solution containing polyethylene glycol in S1 is 5-15wt%, the mass fraction of the hydrogen peroxide solution is 20-30wt%, and the volume ratio of the solution containing polyethylene glycol to the hydrogen peroxide solution is 1:2-3. Preferably, the method for preparing the polyguanidine grafted two-component hollow electrospun fiber membrane in S2 comprises the following steps: S11. dissolving carboxymethyl chitosan in an acetic acid solution to obtain a solution A having a mass fraction of 8 to 15 wt %; S12. dissolving berberine hydrochloride in acetic acid / DMF solution to obtain a solution B having a mass fraction of 5 to 12 wt %; S13. mixing solution A and solution B to obtain an electrospinning shell solution; S14. PVP was dissolved in water, and then RGO was added and ultrasonically dispersed to obtain an electrospinning core layer solution; S15. Coaxially electrospinning the electrospinning shell layer solution and the electrospinning core layer solution in a volume ratio of 5 to 8:1 to obtain an electrospinning fiber membrane; S16. A grafting reaction is carried out on the surface of the electrospun fiber membrane to obtain a polyguanidine-grafted two-component hollow electrospun fiber membrane. Preferably, the volume ratio of solution A to solution B in S13 is 2 to 5:1. Preferably, the mass ratio of PVP to RGO in S14 is 7 to 10:1, and the mass fraction of the obtained electrospinning core layer solution is 8 to 20 wt%. Preferably, the voltage of the coaxial electrospinning in S15 is 16-24 KV, the receiving distance is 15-20 cm, the spinning speed of the core layer is 0.2-0.4 ml / h, and the spinning speed of the shell layer solution is 1-2 ml / h. Preferably, the grafting reaction in S17 comprises the following steps: S21. The polyguanidine is dissolved in water to obtain a solution having a mass fraction of 8 to 12 wt %; S22. Soak the electrospun fiber membrane in PBS buffer, add the solution obtained in S21, and heat the reaction for a certain period of time to achieve grafting. Preferably, the mass ratio of the electrospun fiber membrane to the PBS buffer in S22 is 1:20-30, and the pH of the PBS buffer is 7-8. Preferably, the volume ratio of the PBS buffer in S22 to the solution obtained in S21 is 8 to 15:1. Preferably, the temperature of the heating reaction in S22 is 30-50° C. and the time is 2-5 hours. Beneficial effects: The present invention has the following advantages: 1. In the present invention, the primary hydroxyl group of polyethylene glycol is oxidized to carboxyl group by hydrogen peroxide, and then sodium hydroxide is added to ionize the carboxyl group to carboxylate ions while removing the unreacted hydrogen peroxide. Finally, the polyethylene glycol is removed by the multiple adsorption functions of the polyguanidine-grafted two-component hollow electrospun fiber membrane; 2. The two-component hollow electrospun fiber membrane prepared in the present invention has carboxymethyl chitosan / berberine hydrochloride as the shell layer and a porous graphene membrane as the core layer. Berberine hydrochloride in the shell layer is a quaternary ammonium alkaloid, which can release quaternary ammonium salt cations and adsorb carboxylate ions to achieve the removal of polyethylene glycol. In the core layer, a porous structure is constructed in the RGO fiber membrane by removing PVP, which is beneficial to the adsorption and mass transfer of carboxylate ions. In addition, the electron density on the aromatic ring of RGO is low, forming an electron-deficient environment to attract negatively charged carboxylate ions, generating anion-π interactions, thereby achieving the removal of polyethylene glycol. The hollow fiber membrane has a high specific surface area, providing more active sites for ion adsorption, and the internal cavity can provide a direct channel for ions, shortening the path for ions to diffuse from the solution to the inside of the material, thereby improving the adsorption efficiency. 3. In the present invention, the carboxyl groups on the surface of carboxymethyl chitosan are used to undergo an amidation reaction with the amino groups contained in polyguanidine, and the polyguanidine is grafted onto the surface of the two-component hollow electrospun fiber membrane by forming an amide bond. The guanidine groups in the polyguanidine can combine with carboxylate ions through charge interaction, thereby achieving the removal of polyethylene glycol. DETAILED DESCRIPTION The present invention will be further described below in conjunction with embodiments, which are explanations of the present invention and are not limited to the following embodiments: Example 1 A method for removing polyethylene glycol from water, the method comprising the following steps: S1. Adding a 20 wt % hydrogen peroxide solution to a 5 wt % polyethylene glycol solution, the volume ratio of the polyethylene glycol solution to the hydrogen peroxide solution is 1:2, and after reacting for 30 min, adding a 0.3 mol / L sodium hydroxide solution to adjust the solution pH to 7.5; S2. Filter the solution obtained in S1 using a polyguanidine-grafted two-component hollow electrospun fiber membrane to remove polyethylene glycol from the water; Wherein, the polyguanidine grafted two-component hollow electrospun fiber membrane in step S2 has carboxymethyl chitosan / berberine hydrochloride as a shell layer and a porous RGO membrane as a core layer, and a porous structure is constructed in the RGO fiber membrane by removing PVP from the core layer, and the polyguanidine grafted two-component hollow electrospun fiber membrane has a thickness of 15 μm and a porosity of 80%; The method for preparing the polyguanidine grafted two-component hollow electrospun fiber membrane in S2 comprises the following steps: S11. dissolving carboxymethyl chitosan in an acetic acid solution to obtain a solution A having a mass fraction of 8 wt %; S12. dissolving berberine hydrochloride in acetic acid / DMF solution to obtain a solution B having a mass fraction of 5 wt %; S13. Mixing solution A and solution B in a volume ratio of 2:1 to obtain an electrospinning shell solution; S14. PVP was dissolved in water, and then RGO was added and ultrasonically dispersed, the mass ratio of PVP to RGO was 7:1, and an electrospinning core layer solution with a mass fraction of 8 wt% was obtained; S15. The electrospinning shell solution and the electrospinning core solution were coaxially electrospun in a volume ratio of 5:1. The voltage of the coaxial electrospinning was 16KV, the receiving distance was 15cm, the spinning speed of the core layer was 0.2ml / h, and the spinning speed of the shell solution was 1ml / h to obtain an electrospun fiber membrane; S16. A grafting reaction is carried out on the surface of the electrospun fiber membrane to obtain a polyguanidine-grafted two-component hollow electrospun fiber membrane. Wherein, the grafting reaction in S17 comprises the following steps: S21. The polyguanidine was dissolved in water to obtain a solution having a mass fraction of 8 wt %; S22. The electrospun fiber membrane was immersed in a PBS buffer solution with a pH of 7, the mass ratio of the electrospun fiber membrane to the PBS buffer solution was 1:20, and the solution obtained in S21 was added, the volume of the PBS buffer solution to the solution obtained in S21 was 8:1, and heated to 30°C for 2 hours to achieve grafting. Example 2 A method for removing polyethylene glycol from water, the method comprising the following steps: S1. Adding a 20 wt % hydrogen peroxide solution to a 5 wt % polyethylene glycol solution, the volume ratio of the polyethylene glycol solution to the hydrogen peroxide solution is 1:2, and after reacting for 30 min, adding a 0.3 mol / L sodium hydroxide solution to adjust the solution pH to 7.5; S2. Filter the solution obtained in S1 using a polyguanidine-grafted two-component hollow electrospun fiber membrane to remove polyethylene glycol from the water; Wherein, the polyguanidine grafted two-component hollow electrospun fiber membrane in step S2 has carboxymethyl chitosan / berberine hydrochloride as a shell layer and a porous RGO membrane as a core layer, and a porous structure is constructed in the RGO fiber membrane by removing PVP from the core layer, and the polyguanidine grafted two-component hollow electrospun fiber membrane has a thickness of 15 μm and a porosity of 80%; The method for preparing the polyguanidine grafted two-component hollow electrospun fiber membrane in S2 comprises the following steps: S11. dissolving carboxymethyl chitosan in an acetic acid solution to obtain a solution A having a mass fraction of 8 wt %; S12. dissolving berberine hydrochloride in acetic acid / DMF solution to obtain a solution B having a mass fraction of 5 wt %; S13. Solution A and solution B were mixed in a volume ratio of 3:1 to obtain an electrospinning shell solution; S14. PVP was dissolved in water, and then RGO was added and ultrasonically dispersed, the mass ratio of PVP to RGO was 7:1, and an electrospinning core layer solution with a mass fraction of 8 wt% was obtained; S15. The electrospinning shell solution and the electrospinning core solution were coaxially electrospun in a volume ratio of 5:1. The voltage of the coaxial electrospinning was 16KV, the receiving distance was 15cm, the spinning speed of the core layer was 0.2ml / h, and the spinning speed of the shell solution was 1ml / h to obtain an electrospun fiber membrane; S16. A grafting reaction is carried out on the surface of the electrospun fiber membrane to obtain a polyguanidine-grafted two-component hollow electrospun fiber membrane. Wherein, the grafting reaction in S17 comprises the following steps: S21. The polyguanidine was dissolved in water to obtain a solution having a mass fraction of 8 wt %; S22. The electrospun fiber membrane was immersed in a PBS buffer solution with a pH of 7, the mass ratio of the electrospun fiber membrane to the PBS buffer solution was 1:20, and the solution obtained in S21 was added, the volume of the PBS buffer solution to the solution obtained in S21 was 8:1, and heated to 30°C for 2 hours to achieve grafting. Example 3 A method for removing polyethylene glycol from water, the method comprising the following steps: S1. Adding a 20 wt % hydrogen peroxide solution to a 5 wt % polyethylene glycol solution, the volume ratio of the polyethylene glycol solution to the hydrogen peroxide solution is 1:2, and after reacting for 30 min, adding a 0.3 mol / L sodium hydroxide solution to adjust the solution pH to 7.5; S2. Filter the solution obtained in S1 using a polyguanidine-grafted two-component hollow electrospun fiber membrane to remove polyethylene glycol from the water; Wherein, the polyguanidine grafted two-component hollow electrospun fiber membrane in step S2 has carboxymethyl chitosan / berberine hydrochloride as a shell layer and a porous RGO membrane as a core layer, and a porous structure is constructed in the RGO fiber membrane by removing PVP from the core layer, and the polyguanidine grafted two-component hollow electrospun fiber membrane has a thickness of 15 μm and a porosity of 80%; The method for preparing the polyguanidine grafted two-component hollow electrospun fiber membrane in S2 comprises the following steps: S11. dissolving carboxymethyl chitosan in an acetic acid solution to obtain a solution A having a mass fraction of 8 wt %; S12. dissolving berberine hydrochloride in acetic acid / DMF solution to obtain a solution B having a mass fraction of 5 wt %; S13. Mixing solution A and solution B in a volume ratio of 4:1 to obtain an electrospinning shell solution; S14. PVP was dissolved in water, and then RGO was added and ultrasonically dispersed, the mass ratio of PVP to RGO was 7:1, and an electrospinning core layer solution with a mass fraction of 8 wt% was obtained; S15. The electrospinning shell solution and the electrospinning core solution were coaxially electrospun in a volume ratio of 5:1. The voltage of the coaxial electrospinning was 16KV, the receiving distance was 15cm, the spinning speed of the core layer was 0.2ml / h, and the spinning speed of the shell solution was 1ml / h to obtain an electrospun fiber membrane; S16. A grafting reaction is carried out on the surface of the electrospun fiber membrane to obtain a polyguanidine-grafted two-component hollow electrospun fiber membrane. Wherein, the grafting reaction in S17 comprises the following steps: S21. The polyguanidine was dissolved in water to obtain a solution having a mass fraction of 8 wt %; S22. The electrospun fiber membrane was immersed in a PBS buffer solution with a pH of 7, the mass ratio of the electrospun fiber membrane to the PBS buffer solution was 1:20, and the solution obtained in S21 was added, the volume of the PBS buffer solution to the solution obtained in S21 was 8:1, and heated to 30°C for 2 hours to achieve grafting. Example 4 A method for removing polyethylene glycol from water, the method comprising the following steps: S1. Adding a 25 wt % hydrogen peroxide solution to a 10 wt % polyethylene glycol solution, the volume ratio of the polyethylene glycol solution to the hydrogen peroxide solution is 1:2, and after reacting for 30 min, adding a 0.3 mol / L sodium hydroxide solution to adjust the solution pH to 8; S2. Filter the solution obtained in S1 using a polyguanidine-grafted two-component hollow electrospun fiber membrane to remove polyethylene glycol from the water; Wherein, the polyguanidine grafted two-component hollow electrospun fiber membrane in step S2 has carboxymethyl chitosan / berberine hydrochloride as a shell layer and a porous RGO membrane as a core layer, and a porous structure is constructed in the RGO fiber membrane by removing PVP from the core layer, and the polyguanidine grafted two-component hollow electrospun fiber membrane has a thickness of 18 μm and a porosity of 82%; The method for preparing the polyguanidine grafted two-component hollow electrospun fiber membrane in S2 comprises the following steps: S11. dissolving carboxymethyl chitosan in an acetic acid solution to obtain a solution A having a mass fraction of 10 wt %; S12. dissolving berberine hydrochloride in acetic acid / DMF solution to obtain a solution B having a mass fraction of 8 wt %; S13. Solution A and solution B were mixed in a volume ratio of 5:1 to obtain an electrospinning shell solution; S14. PVP was dissolved in water, and then RGO was added and ultrasonically dispersed, the mass ratio of PVP to RGO was 9:1, and an electrospinning core layer solution with a mass fraction of 12 wt% was obtained; S15. The electrospinning shell solution and the electrospinning core solution were coaxially electrospun in a volume ratio of 5:1. The voltage of the coaxial electrospinning was 20 KV, the receiving distance was 18 cm, the spinning speed of the core layer was 0.3 ml / h, and the spinning speed of the shell solution was 2 ml / h to obtain an electrospun fiber membrane; S16. A grafting reaction is carried out on the surface of the electrospun fiber membrane to obtain a polyguanidine-grafted two-component hollow electrospun fiber membrane. Wherein, the grafting reaction in S17 comprises the following steps: S21. The polyguanidine was dissolved in water to obtain a solution having a mass fraction of 10 wt%; S22. The electrospun fiber membrane was immersed in a PBS buffer solution with a pH of 7, the mass ratio of the electrospun fiber membrane to the PBS buffer solution was 1:25, and the solution obtained in S21 was added, the volume of the PBS buffer solution to the solution obtained in S21 was 12:1, and the membrane was heated to 40°C for 3 hours to achieve grafting. Example 5 A method for removing polyethylene glycol from water, the method comprising the following steps: S1. Adding a 30 wt % hydrogen peroxide solution to a 15 wt % polyethylene glycol solution, wherein the volume ratio of the polyethylene glycol solution to the hydrogen peroxide solution is 1:2, and after reacting for 80 min, adding a 0.5 mol / L sodium hydroxide solution to adjust the solution pH to 8; S2. Filter the solution obtained in S1 using a polyguanidine-grafted two-component hollow electrospun fiber membrane to remove polyethylene glycol from the water; Wherein, the polyguanidine grafted two-component hollow electrospun fiber membrane in step S2 has carboxymethyl chitosan / berberine hydrochloride as a shell layer and a porous RGO membrane as a core layer, and a porous structure is constructed in the RGO fiber membrane by removing PVP from the core layer, and the polyguanidine grafted two-component hollow electrospun fiber membrane has a thickness of 15 μm and a porosity of 88%; The method for preparing the polyguanidine grafted two-component hollow electrospun fiber membrane in S2 comprises the following steps: S11. dissolving carboxymethyl chitosan in an acetic acid solution to obtain a solution A having a mass fraction of 15 wt %; S12. dissolving berberine hydrochloride in acetic acid / DMF solution to obtain a solution B having a mass fraction of 8 wt %; S13. Solution A and solution B were mixed in a volume ratio of 5:1 to obtain an electrospinning shell solution; S14. PVP was dissolved in water, and then RGO was added and ultrasonically dispersed, the mass ratio of PVP to RGO was 9:1, and an electrospinning core layer solution with a mass fraction of 12 wt% was obtained; S15. The electrospinning shell solution and the electrospinning core solution were coaxially electrospun in a volume ratio of 8:1. The voltage of the coaxial electrospinning was 22KV, the receiving distance was 18cm, the spinning speed of the core layer was 0.3ml / h, and the spinning speed of the shell solution was 2ml / h to obtain an electrospun fiber membrane; S16. A grafting reaction is carried out on the surface of the electrospun fiber membrane to obtain a polyguanidine-grafted two-component hollow electrospun fiber membrane. Wherein, the grafting reaction in S17 comprises the following steps: S21. The polyguanidine was dissolved in water to obtain a solution having a mass fraction of 10 wt%; S22. The electrospun fiber membrane was immersed in a PBS buffer solution with a pH of 7, the mass ratio of the electrospun fiber membrane to the PBS buffer solution was 1:30, and the solution obtained in S21 was added, the volume of the PBS buffer solution to the solution obtained in S21 was 15:1, and the mixture was heated to 50°C for 3 hours to achieve grafting. Example 6 A method for removing polyethylene glycol from water, the method comprising the following steps: S1. Adding a 28 wt % hydrogen peroxide solution to a 12 wt % polyethylene glycol solution, wherein the volume ratio of the polyethylene glycol solution to the hydrogen peroxide solution is 1:3, and after reacting for 80 min, adding a 0.4 mol / L sodium hydroxide solution to adjust the solution pH to 8; S2. Filter the solution obtained in S1 using a polyguanidine-grafted two-component hollow electrospun fiber membrane to remove polyethylene glycol from the water; Wherein, the polyguanidine grafted two-component hollow electrospun fiber membrane in step S2 has carboxymethyl chitosan / berberine hydrochloride as a shell layer and a porous RGO membrane as a core layer, and a porous structure is constructed in the RGO fiber membrane by removing PVP from the core layer, and the polyguanidine grafted two-component hollow electrospun fiber membrane has a thickness of 15 μm and a porosity of 90%; The method for preparing the polyguanidine grafted two-component hollow electrospun fiber membrane in S2 comprises the following steps: S11. dissolving carboxymethyl chitosan in an acetic acid solution to obtain a solution A having a mass fraction of 15 wt %; S12. dissolving berberine hydrochloride in acetic acid / DMF solution to obtain a solution B having a mass fraction of 8 wt %; S13. Solution A and solution B were mixed in a volume ratio of 5:1 to obtain an electrospinning shell solution; S14. PVP was dissolved in water, and then RGO was added and ultrasonically dispersed, the mass ratio of PVP to RGO was 9:1, and an electrospinning core layer solution with a mass fraction of 12 wt% was obtained; S15. The electrospinning shell solution and the electrospinning core solution were coaxially electrospun in a volume ratio of 8:1. The voltage of the coaxial electrospinning was 20 KV, the receiving distance was 15 cm, the spinning speed of the core layer was 0.3 ml / h, and the spinning speed of the shell solution was 1.5 ml / h to obtain an electrospun fiber membrane; S16. A grafting reaction is carried out on the surface of the electrospun fiber membrane to obtain a polyguanidine-grafted two-component hollow electrospun fiber membrane. Wherein, the grafting reaction in S17 comprises the following steps: S21. The polyguanidine was dissolved in water to obtain a solution having a mass fraction of 12 wt %; S22. The electrospun fiber membrane was immersed in a PBS buffer solution with a pH of 8, the mass ratio of the electrospun fiber membrane to the PBS buffer solution was 1:30, and the solution obtained in S21 was added, the volume of the PBS buffer solution to the solution obtained in S21 was 14:1, and the membrane was heated to 50°C for 4 hours to achieve grafting. Example 7 A method for removing polyethylene glycol from water, the method comprising the following steps: S1. Adding a 28 wt % hydrogen peroxide solution to a 12 wt % polyethylene glycol solution, wherein the volume ratio of the polyethylene glycol solution to the hydrogen peroxide solution is 1:3, and after reacting for 80 min, adding a 0.4 mol / L sodium hydroxide solution to adjust the solution pH to 8; S2. Filter the solution obtained in S1 using a polyguanidine-grafted two-component hollow electrospun fiber membrane to remove polyethylene glycol from the water; Wherein, the polyguanidine grafted two-component hollow electrospun fiber membrane in step S2 has carboxymethyl chitosan / berberine hydrochloride as a shell layer and a porous RGO membrane as a core layer, and a porous structure is constructed in the RGO fiber membrane by removing PVP from the core layer, and the polyguanidine grafted two-component hollow electrospun fiber membrane has a thickness of 20 μm and a porosity of 82%; The method for preparing the polyguanidine grafted two-component hollow electrospun fiber membrane in S2 comprises the following steps: S11. dissolving carboxymethyl chitosan in an acetic acid solution to obtain a solution A having a mass fraction of 15 wt %; S12. dissolving berberine hydrochloride in acetic acid / DMF solution to obtain a solution B having a mass fraction of 8 wt %; S13. Solution A and solution B were mixed in a volume ratio of 5:1 to obtain an electrospinning shell solution; S14. PVP was dissolved in water, and then RGO was added and ultrasonically dispersed, the mass ratio of PVP to RGO was 9:1, and an electrospinning core layer solution with a mass fraction of 12 wt% was obtained; S15. The electrospinning shell solution and the electrospinning core solution were coaxially electrospun in a volume ratio of 8:1. The voltage of the coaxial electrospinning was 20 KV, the receiving distance was 15 cm, the spinning speed of the core layer was 0.3 ml / h, and the spinning speed of the shell solution was 1.5 ml / h to obtain an electrospun fiber membrane; S16. A grafting reaction is carried out on the surface of the electrospun fiber membrane to obtain a polyguanidine-grafted two-component hollow electrospun fiber membrane. Wherein, the grafting reaction in S17 comprises the following steps: S21. The polyguanidine was dissolved in water to obtain a solution having a mass fraction of 10 wt%; S22. The electrospun fiber membrane was immersed in a PBS buffer solution with a pH of 8, the mass ratio of the electrospun fiber membrane to the PBS buffer solution was 1:30, and the solution obtained in S21 was added, the volume of the PBS buffer solution to the solution obtained in S21 was 14:1, and the membrane was heated to 50°C for 4 hours to achieve grafting. Example 8 A method for removing polyethylene glycol from water, the method comprising the following steps: S1. Adding a 28 wt % hydrogen peroxide solution to a 12 wt % polyethylene glycol solution, wherein the volume ratio of the polyethylene glycol solution to the hydrogen peroxide solution is 1:3, and after reacting for 80 min, adding a 0.4 mol / L sodium hydroxide solution to adjust the solution pH to 8; S2. Filter the solution obtained in S1 using a polyguanidine-grafted two-component hollow electrospun fiber membrane to remove polyethylene glycol from the water; Wherein, the polyguanidine grafted two-component hollow electrospun fiber membrane in step S2 has carboxymethyl chitosan / berberine hydrochloride as a shell layer and a porous RGO membrane as a core layer, and a porous structure is constructed in the RGO fiber membrane by removing PVP from the core layer, and the polyguanidine grafted two-component hollow electrospun fiber membrane has a thickness of 20 μm and a porosity of 82%; The method for preparing the polyguanidine grafted two-component hollow electrospun fiber membrane in S2 comprises the following steps: S11. dissolving carboxymethyl chitosan in an acetic acid solution to obtain a solution A having a mass fraction of 15 wt %; S12. dissolving berberine hydrochloride in acetic acid / DMF solution to obtain a solution B having a mass fraction of 8 wt %; S13. Solution A and solution B were mixed in a volume ratio of 5:1 to obtain an electrospinning shell solution; S14. PVP was dissolved in water, and then RGO was added and ultrasonically dispersed, the mass ratio of PVP to RGO was 9:1, and an electrospinning core layer solution with a mass fraction of 12 wt% was obtained; S15. The electrospinning shell solution and the electrospinning core solution were coaxially electrospun in a volume ratio of 8:1. The voltage of the coaxial electrospinning was 20 KV, the receiving distance was 15 cm, the spinning speed of the core layer was 0.3 ml / h, and the spinning speed of the shell solution was 1.5 ml / h to obtain an electrospun fiber membrane; S16. A grafting reaction is carried out on the surface of the electrospun fiber membrane to obtain a polyguanidine-grafted two-component hollow electrospun fiber membrane. Wherein, the grafting reaction in S17 comprises the following steps: S21. The polyguanidine was dissolved in water to obtain a solution having a mass fraction of 12 wt %; S22. The electrospun fiber membrane was immersed in a PBS buffer solution with a pH of 8, the mass ratio of the electrospun fiber membrane to the PBS buffer solution was 1:30, and the solution obtained in S21 was added, the volume of the PBS buffer solution to the solution obtained in S21 was 14:1, and the membrane was heated to 50°C for 4 hours to achieve grafting. Comparative Example 1 A method for removing polyethylene glycol from water, the method comprising the following steps: S1. Adding a 20 wt % hydrogen peroxide solution to a 5 wt % polyethylene glycol solution, the volume ratio of the polyethylene glycol solution to the hydrogen peroxide solution is 1:2, and after reacting for 30 min, adding a 0.3 mol / L sodium hydroxide solution to adjust the solution pH to 7.5; S2. Filter the solution obtained in S1 using a polyguanidine-grafted two-component hollow electrospun fiber membrane to remove polyethylene glycol from the water; Wherein, the polyguanidine grafted two-component hollow electrospun fiber membrane in step S2 has carboxymethyl chitosan / berberine hydrochloride as a shell layer and a porous RGO membrane as a core layer, and a porous structure is constructed in the RGO fiber membrane by removing PVP from the core layer, and the polyguanidine grafted two-component hollow electrospun fiber membrane has a thickness of 15 μm and a porosity of 80%; The method for preparing the polyguanidine grafted two-component hollow electrospun fiber membrane in S2 comprises the following steps: S11. dissolving carboxymethyl chitosan in an acetic acid solution to obtain a solution A having a mass fraction of 8 wt %; S12. dissolving berberine hydrochloride in acetic acid / DMF solution to obtain a solution B having a mass fraction of 5 wt %; S13. Mixing solution A and solution B in a volume ratio of 1:1 to obtain an electrospinning shell solution; S14. PVP was dissolved in water, and then RGO was added and ultrasonically dispersed, the mass ratio of PVP to RGO was 7:1, and an electrospinning core layer solution with a mass fraction of 8 wt% was obtained; S15. The electrospinning shell solution and the electrospinning core solution were coaxially electrospun in a volume ratio of 5:1. The voltage of the coaxial electrospinning was 16KV, the receiving distance was 15cm, the spinning speed of the core layer was 0.2ml / h, and the spinning speed of the shell solution was 1ml / h to obtain an electrospun fiber membrane; S16. A grafting reaction is carried out on the surface of the electrospun fiber membrane to obtain a polyguanidine-grafted two-component hollow electrospun fiber membrane. Wherein, the grafting reaction in S17 comprises the following steps: S21. The polyguanidine was dissolved in water to obtain a solution having a mass fraction of 8 wt %; S22. The electrospun fiber membrane was immersed in a PBS buffer solution with a pH of 7, the mass ratio of the electrospun fiber membrane to the PBS buffer solution was 1:20, and the solution obtained in S21 was added, the volume of the PBS buffer solution to the solution obtained in S21 was 8:1, and heated to 30°C for 2 hours to achieve grafting. Comparative Example 2 A method for removing polyethylene glycol from water, the method comprising the following steps: S1. Adding a 20 wt % hydrogen peroxide solution to a 5 wt % polyethylene glycol solution, the volume ratio of the polyethylene glycol solution to the hydrogen peroxide solution is 1:2, and after reacting for 30 min, adding a 0.3 mol / L sodium hydroxide solution to adjust the solution pH to 7.5; S2. Filter the solution obtained in S1 using a polyguanidine-grafted two-component hollow electrospun fiber membrane to remove polyethylene glycol from the water; Wherein, the polyguanidine grafted two-component hollow electrospun fiber membrane in step S2 has carboxymethyl chitosan / berberine hydrochloride as a shell layer and a porous RGO membrane as a core layer, and a porous structure is constructed in the RGO fiber membrane by removing PVP from the core layer, and the polyguanidine grafted two-component hollow electrospun fiber membrane has a thickness of 15 μm and a porosity of 80%; The method for preparing the polyguanidine grafted two-component hollow electrospun fiber membrane in S2 comprises the following steps: S11. dissolving carboxymethyl chitosan in an acetic acid solution to obtain a solution A having a mass fraction of 8 wt %; S12. dissolving berberine hydrochloride in acetic acid / DMF solution to obtain a solution B having a mass fraction of 5 wt %; S13. Solution A and solution B were mixed in a volume ratio of 6:1 to obtain an electrospinning shell solution; S14. PVP was dissolved in water, and then RGO was added and ultrasonically dispersed, the mass ratio of PVP to RGO was 7:1, and an electrospinning core layer solution with a mass fraction of 8 wt% was obtained; S15. The electrospinning shell solution and the electrospinning core solution were coaxially electrospun in a volume ratio of 5:1. The voltage of the coaxial electrospinning was 16KV, the receiving distance was 15cm, the spinning speed of the core layer was 0.2ml / h, and the spinning speed of the shell solution was 1ml / h to obtain an electrospun fiber membrane; S16. A grafting reaction is carried out on the surface of the electrospun fiber membrane to obtain a polyguanidine-grafted two-component hollow electrospun fiber membrane. Wherein, the grafting reaction in S17 comprises the following steps: S21. The polyguanidine was dissolved in water to obtain a solution having a mass fraction of 8 wt %; S22. The electrospun fiber membrane was immersed in a PBS buffer solution with a pH of 7, the mass ratio of the electrospun fiber membrane to the PBS buffer solution was 1:20, and the solution obtained in S21 was added, the volume of the PBS buffer solution to the solution obtained in S21 was 8:1, and heated to 30°C for 2 hours to achieve grafting. Table 1 Effect of the volume ratio of solution A to solution B on the removal rate of polyethylene glycol name The volume ratio of solution A to solution B Removal rate of polyethylene glycol / % Example 1 2:1 97.8 Example 2 3:1 96.3 Example 3 4:1 96.1 Comparative Example 1 1:1 82.7 Comparative Example 2 6:1 85.7 Comparative Example 3 A method for removing polyethylene glycol from water, the method comprising the following steps: S1. Adding a 25 wt % hydrogen peroxide solution to a 10 wt % polyethylene glycol solution, the volume ratio of the polyethylene glycol solution to the hydrogen peroxide solution is 1:2, and after reacting for 30 min, adding a 0.3 mol / L sodium hydroxide solution to adjust the solution pH to 8; S2. Filter the solution obtained in S1 using a polyguanidine-grafted two-component hollow electrospun fiber membrane to remove polyethylene glycol from the water; Wherein, the polyguanidine grafted two-component hollow electrospun fiber membrane in step S2 has carboxymethyl chitosan / berberine hydrochloride as a shell layer and a porous RGO membrane as a core layer, and a porous structure is constructed in the RGO fiber membrane by removing PVP from the core layer, and the polyguanidine grafted two-component hollow electrospun fiber membrane has a thickness of 18 μm and a porosity of 82%; The method for preparing the polyguanidine grafted two-component hollow electrospun fiber membrane in S2 comprises the following steps: S11. dissolving carboxymethyl chitosan in an acetic acid solution to obtain a solution A having a mass fraction of 10 wt %; S12. dissolving berberine hydrochloride in acetic acid / DMF solution to obtain a solution B having a mass fraction of 8 wt %; S13. Solution A and solution B were mixed in a volume ratio of 5:1 to obtain an electrospinning shell solution; S14. PVP was dissolved in water, and then RGO was added and ultrasonically dispersed, the mass ratio of PVP to RGO was 9:1, and an electrospinning core layer solution with a mass fraction of 12 wt% was obtained; S15. The electrospinning shell solution and the electrospinning core solution were coaxially electrospun in a volume ratio of 5:1. The voltage of the coaxial electrospinning was 20 KV, the receiving distance was 18 cm, the spinning speed of the core layer was 0.3 ml / h, and the spinning speed of the shell solution was 2 ml / h to obtain a two-component electrospun fiber membrane; S16. Soak the bicomponent electrospun fiber membrane obtained in S15 in water, and obtain a bicomponent hollow electrospun fiber membrane after drying. Table 2 Effect of polyguanidine on the removal rate of polyethylene glycol name Whether to graft polyguanidine Removal rate of polyethylene glycol / % Example 4 yes 96.8 Comparative Example 3 no 73.1 Comparative Example 4 A method for removing polyethylene glycol from water, the method comprising the following steps: S1. Adding a 30 wt % hydrogen peroxide solution to a 15 wt % polyethylene glycol solution, wherein the volume ratio of the polyethylene glycol solution to the hydrogen peroxide solution is 1:2, and after reacting for 80 min, adding a 0.5 mol / L sodium hydroxide solution to adjust the solution pH to 8; S2. Filter the solution obtained in S1 using a polyguanidine-grafted two-component hollow electrospun fiber membrane to remove polyethylene glycol from the water; Wherein, the polyguanidine grafted two-component hollow electrospun fiber membrane in step S2 has carboxymethyl chitosan / berberine hydrochloride as a shell layer and a porous RGO membrane as a core layer, and a porous structure is constructed in the RGO fiber membrane by removing PVP from the core layer, and the polyguanidine grafted two-component hollow electrospun fiber membrane has a thickness of 15 μm and a porosity of 88%; The method for preparing the polyguanidine grafted two-component hollow electrospun fiber membrane in S2 comprises the following steps: S11. dissolving carboxymethyl chitosan in an acetic acid solution to obtain a shell solution having a mass fraction of 15 wt %; S14. PVP was dissolved in water, and then RGO was added and ultrasonically dispersed, the mass ratio of PVP to RGO was 9:1, and an electrospinning core layer solution with a mass fraction of 12 wt% was obtained; S15. The electrospinning shell solution and the electrospinning core solution were coaxially electrospun in a volume ratio of 8:1. The voltage of the coaxial electrospinning was 22KV, the receiving distance was 18cm, the spinning speed of the core layer was 0.3ml / h, and the spinning speed of the shell solution was 2ml / h to obtain an electrospun fiber membrane; S16. A grafting reaction is carried out on the surface of the electrospun fiber membrane to obtain a polyguanidine-grafted two-component hollow electrospun fiber membrane. Wherein, the grafting reaction in S17 comprises the following steps: S21. The polyguanidine was dissolved in water to obtain a solution having a mass fraction of 10 wt%; S22. The electrospun fiber membrane was immersed in a PBS buffer solution with a pH of 7, the mass ratio of the electrospun fiber membrane to the PBS buffer solution was 1:30, and the solution obtained in S21 was added, the volume of the PBS buffer solution to the solution obtained in S21 was 15:1, and the mixture was heated to 50°C for 3 hours to achieve grafting. Table 3 Effect of berberine hydrochloride on the removal rate of polyethylene glycol name Whether to add berberine hydrochloride Removal rate of polyethylene glycol / % Example 5 yes 95.8 Comparative Example 4 no 77.2 Comparative Example 5 A method for removing polyethylene glycol from water, the method comprising the following steps: S1. Adding a 28 wt % hydrogen peroxide solution to a 12 wt % polyethylene glycol solution, wherein the volume ratio of the polyethylene glycol solution to the hydrogen peroxide solution is 1:3, and after reacting for 80 min, adding a 0.4 mol / L sodium hydroxide solution to adjust the solution pH to 8; S2. Filter the solution obtained in S1 using a polyguanidine-grafted two-component hollow electrospun fiber membrane to remove polyethylene glycol from the water; Wherein, the polyguanidine grafted two-component hollow electrospun fiber membrane in step S2 has carboxymethyl chitosan / berberine hydrochloride as a shell layer and a porous RGO membrane as a core layer, and a porous structure is constructed in the RGO fiber membrane by removing PVP from the core layer, and the polyguanidine grafted two-component hollow electrospun fiber membrane has a thickness of 15 μm and a porosity of 90%; The method for preparing the polyguanidine grafted two-component hollow electrospun fiber membrane in S2 comprises the following steps: S11. dissolving carboxymethyl chitosan in an acetic acid solution to obtain a solution A having a mass fraction of 15 wt %; S12. dissolving berberine hydrochloride in acetic acid / DMF solution to obtain a solution B having a mass fraction of 8 wt %; S13. Mixing solution A and solution B in a volume ratio of 5:1 to obtain an electrospinning solution; S14. The solution obtained in S13 was used for electrospinning, the voltage of the electrospinning was 20 KV, the receiving distance was 15 cm, the spinning speed was 1.5 ml / h, and an electrospun fiber membrane was obtained; S16. Performing a grafting reaction on the surface of the electrospun fiber membrane to obtain a polyguanidine-grafted electrospun fiber membrane. Wherein, the grafting reaction in S16 comprises the following steps: S21. The polyguanidine was dissolved in water to obtain a solution having a mass fraction of 12 wt %; S22. The electrospun fiber membrane was immersed in a PBS buffer solution with a pH of 8, the mass ratio of the electrospun fiber membrane to the PBS buffer solution was 1:30, and the solution obtained in S21 was added, the volume of the PBS buffer solution to the solution obtained in S21 was 14:1, and the membrane was heated to 50°C for 4 hours to achieve grafting. Table 4 Effect of hollow structure on polyethylene glycol removal rate name Is there a hollow structure? Removal rate of polyethylene glycol / % Example 6 yes 96.2 Comparative Example 5 no 72.9 Comparative Example 6 The difference between this comparative example and Example 7 is that the mass fraction of the polyguanidine solution is 4 wt %. Comparative Example 7 The difference between this comparative example and Example 7 is that the mass fraction of the polyguanidine solution is 18 wt %. Table 5 Effect of the mass fraction of polyguanidine on the removal rate of polyethylene glycol name Mass fraction of polyguanidine / wt% Removal rate of polyethylene glycol / % Example 7 10 95.3 Example 8 12 96.8 Comparative Example 6 4 78.4 Comparative Example 7 18 70.5 Comparative Example 8 The difference between this comparative example and Example 8 is that berberine hydrochloride is not added to the shell layer but a quaternary ammonium salt is added. Table 6 Effect of quaternary ammonium salt types on polyethylene glycol removal rate Contrast 9 The difference between this comparative example and Example 7 is that the porosity of the polyguanidine-grafted two-component hollow electrospun fiber membrane is 70%. Comparative Example 10 The difference between this comparative example and Example 7 is that the porosity of the polyguanidine-grafted two-component hollow electrospun fiber membrane is 93%. Table 7 Effect of porosity on polyethylene glycol removal rate name Porosity / % Removal rate of polyethylene glycol % Example 7 82 96.8 Comparative Example 9 70 90.7 Comparative Example 10 93 73.5 Performance Testing In each embodiment and comparative example, the separation flux and the number of times that the separation flux can be reused are shown in Table 8. Table 8 Separation flux and number of reusable times name <![CDATA[Separation flux / (L·m -2 ·h -1 )]]> Reusable times Example 1 7662 10 Example 2 7537 8 Example 3 7806 10 Example 4 8023 9 Example 5 7654 8 Example 6 8139 8 Example 7 7912 9 Example 8 8120 10 Comparative Example 1 6654 9 Comparative Example 2 6920 8 Comparative Example 3 7036 4 Comparative Example 4 7133 5 Comparative Example 5 7159 6 Comparative Example 6 7281 7 Comparative Example 7 7338 5 Comparative Example 8 7680 6 Comparative Example 9 6342 8 Comparative Example 10 8477 7 Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A method for removing polyethylene glycol from water, characterized in that: The method comprises the following steps: S1. Add hydrogen peroxide solution to the solution containing polyethylene glycol, add sodium hydroxide solution after a certain reaction time, and adjust the pH of the solution to 7.5-8.5; S2. Filter the solution obtained in S1 using a polyguanidine-grafted two-component hollow electrospun fiber membrane to remove polyethylene glycol from the water; Among them, the polyguanidine grafted two-component hollow electrospun fiber membrane in step S2 has carboxymethyl chitosan / berberine hydrochloride as the shell layer and a porous RGO membrane as the core layer. The core layer is removed by removing PVP to construct a porous structure in the RGO fiber membrane. The thickness of the polyguanidine grafted two-component hollow electrospun fiber membrane is 15 to 25 μm, and the porosity is 80 to 90%.

2. The method for removing polyethylene glycol from water according to claim 1, characterized in that: The mass fraction of the polyethylene glycol solution in S1 is 5-15wt%, the mass fraction of the hydrogen peroxide solution is 20-30wt%, the volume ratio of the polyethylene glycol solution to the hydrogen peroxide solution is 1:2-3, the reaction time is 30-80min, and the concentration of the sodium hydroxide solution is 0.3-0.6mol / L.

3. The method for removing polyethylene glycol from water according to claim 1, characterized in that: The preparation method of the polyguanidine grafted two-component hollow electrospun fiber membrane in S2 comprises the following steps: S11. dissolving carboxymethyl chitosan in an acetic acid solution to obtain a solution A having a mass fraction of 8 to 15 wt %; S12. dissolving berberine hydrochloride in acetic acid / DMF solution to obtain a solution B having a mass fraction of 5 to 12 wt %; S13. mixing solution A and solution B to obtain an electrospinning shell solution; S14. PVP was dissolved in water, and then RGO was added and ultrasonically dispersed to obtain an electrospinning core layer solution; S15. Coaxially electrospinning the electrospinning shell layer solution and the electrospinning core layer solution in a volume ratio of 5 to 8:1 to obtain an electrospinning fiber membrane; S16. A grafting reaction is carried out on the surface of the electrospun fiber membrane to obtain a polyguanidine-grafted two-component hollow electrospun fiber membrane.

4. The method for removing polyethylene glycol from water according to claim 3, characterized in that: The volume ratio of solution A to solution B in S13 is 2 to 5:

1.

5. The method for removing polyethylene glycol from water according to claim 3, characterized in that: The mass ratio of PVP to RGO in S14 is 7-10:1, and the mass fraction of the obtained electrospinning core layer solution is 8-20wt%.

6. The method for removing polyethylene glycol from water according to claim 3, characterized in that: The voltage of the coaxial electrospinning in S15 is 16-24 KV, the receiving distance is 15-20 cm, the spinning speed of the core layer is 0.2-0.4 ml / h, and the spinning speed of the shell layer solution is 1-2 ml / h.

7. The method for removing polyethylene glycol from water according to claim 3, characterized in that: The grafting reaction in S16 comprises the following steps: S21. The polyguanidine is dissolved in water to obtain a solution having a mass fraction of 8 to 12 wt %; S22. Soak the electrospun fiber membrane in PBS buffer, add the solution obtained in S21, and heat the reaction for a certain period of time to achieve grafting.

8. The method for removing polyethylene glycol from water according to claim 7, characterized in that: The mass ratio of the electrospun fiber membrane to the PBS buffer in the S22 is 1:20-30, and the pH of the PBS buffer is 7-8.

9. The method for removing polyethylene glycol from water according to claim 7, characterized in that: The volume ratio of the PBS buffer in S22 to the solution obtained in S21 is 8 to 15:

1.

10. The method for removing polyethylene glycol from water according to claim 7, characterized in that: The temperature of the heating reaction in S22 is 30-50° C. and the time is 2-5 hours.

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