Cleaning agent for filtering membrane and preparation method of cleaning agent

Abstract

The invention provides a cleaning agent for a filtering membrane and a preparation method of the cleaning agent, and belongs to the technical field of cleaning agents. The cleaning agent is prepared from the following raw materials in parts by weight: 3-15 parts of a surfactant, 12-40 parts of a solubilizer, 2-5 parts of a pH regulator and 2-5 parts of a chelating agent. The cleaning agent for the filtering membrane prepared by the invention has good destroying and eliminating effects on scale deposit of the filtering membrane, reduces formation of the scale, destroys crystal structures of the scale, promotes swelling, fluffiness, dispersion and dissolution of the scale deposit, has a good cleaning effect, is good in biocompatibility, safe and environment-friendly, has no destroying effect on the filtering membrane, and can be used as a cleaning agent for the filtering membrane. After the cleaning agent is used, the cleaning effect of deposited scales can be completed through simple rinsing, and the cleaning agent is simple in using method, high in efficiency and wide in application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of cleaning agents, and in particular to a cleaning agent for a filter membrane and a preparation method thereof. Background Art

[0002] Filtration membranes tend to foul during processing, and membranes provided within separation equipment can be treated using clean-in-place (CIP) methods to provide flushing, rinsing, pretreatment, cleaning, disinfection, and preservation. Fouling manifests itself as flux decay over operating time. Flux decay is typically a decrease in permeate flow or permeation rate that occurs when all operating parameters, such as pressure, feed flow rate, temperature, and feed concentration, remain constant.

[0003] In general, membrane fouling is a complex process and occurs due to many factors, including electrostatic attraction, hydrophobic and hydrophilic interactions, deposition and accumulation of feed components such as suspended particles, impermeable dissolved solutes and even normally permeable solutes on the membrane surface and / or in the membrane pores. It is expected that almost all feed components will foul the membrane to a certain extent. Fouling components and deposits may include inorganic salts, particles, microorganisms and organic matter. Filter membranes generally require regular cleaning to allow successful industrial applications in separation equipment, such as process areas such as food, dairy products and beverage industries.

[0004] Chemical energy in the form of detergents and cleaning agents can be used to dissolve or disperse dirt (foulant) or dirt. Thermal energy in the form of heat can be used to help the action of chemical cleaning agents. Generally speaking, the higher the cleaning temperature of the solution, the more effective it is as a cleaning process, although most membrane materials have temperature limitations due to the constituent materials. Many membranes have chemical limitations in addition. Generally speaking, it has been found that the type of cleaning agent and the chemical treatment performed on the membrane can affect the working life of the membrane. For example, many polyamide reverse osmosis membranes have chlorine limitations because chlorine can have an oxidative attack and a tendency to destroy the membrane. Excessive use of oxidizing chemicals, such as sodium hypochlorite (chlorine bleach) or hydrogen peroxide, etc., will have usage restrictions due to irreversible destruction of some polymer membranes.

[0005] Chinese invention patent CN106237864B discloses a reverse osmosis membrane cleaning agent and a method of using the same. The reverse osmosis membrane cleaning agent includes an alkaline cleaning agent and an acidic cleaning agent, and is mainly used to remove single inorganic dirt such as barium and strontium scale, and is not suitable for treating complex dirt such as milk scale that is composed of organic pollutants, inorganic pollutants and biologically active pollutants. Summary of the invention

[0006] The purpose of the present invention is to provide a cleaning agent for filter membrane and a preparation method thereof, which has a good destroying and eliminating effect on the scale accumulation of the filter membrane, reduces the formation of scale, destroys the crystal structure of scale, thereby promoting the swelling, fluffiness, dispersion and dissolution of scale accumulation, thereby having a good cleaning effect. At the same time, it has good biocompatibility, is safe and environmentally friendly, has no destructive effect on the filter membrane, and after use, a simple rinsing can complete the scale removal effect. The method of use is simple, the efficiency is high, and it has broad application prospects.

[0007] The technical solution of the present invention is achieved in this way: The invention provides a cleaning agent for a filter membrane, which is prepared from the following raw materials by weight: 3-15 parts of a surfactant, 12-40 parts of a solubilizer, 2-5 parts of a pH regulator and 2-5 parts of a chelating agent, wherein the chelating agent is a mixture of a modified chelating agent and a chemical chelating agent, and the mass ratio is 10:3-5, and the modified chelating agent is a modified chelating agent obtained by coating activated carbon with graphene oxide, depositing magnetic ferroferric oxide, modifying the surface with tannic acid, loading chitosan and silk protein peptide, and reacting the surface with phytic acid and beta-cyclodextrin.

[0008] As a further improvement of the present invention, the surfactant is a mixture of decyl glucoside and anionic surfactant LAS, with a mass ratio of 1:0.5-1, the solubilizer is at least one of propylene glycol, sodium isopropyl sulfonate, and glycerol, the pH adjuster is selected from at least one of potassium carbonate, potassium bicarbonate, sodium carbonate, sodium bicarbonate, and sodium hydroxide, and the chemical chelating agent is selected from at least one of sodium gluconate, sodium gluconate heptanoate, ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetic acid, and tetrasodium glutamate diacetate.

[0009] As a further improvement of the present invention, the preparation method of the modified chelating agent is as follows: S1. Pretreatment of activated carbon: crushing wood activated carbon, ball milling, adding to alkali solution, hydrothermal reaction, centrifugation, washing, drying, and obtaining pretreated activated carbon; S2. Preparation of wrinkled activated carbon: adding graphene oxide to water, adding pretreated activated carbon, ultrasonically dispersing uniformly, spray drying, and obtaining wrinkled activated carbon; S3. Preparation of magnetic activated carbon: adding folded activated carbon to water, adding ferric chloride and ferrous chloride under inert gas protection, adding ammonia water dropwise, heating and stirring the reaction, centrifuging, washing, drying, and calcining to obtain magnetic activated carbon; S4. Preparation of modified magnetic activated carbon: adding magnetic activated carbon to water, adding tannic acid and a catalyst, heating and stirring to react, separating with a magnet, washing, and drying to obtain modified magnetic activated carbon; S5. Preparation of modified magnetic activated carbon composite: dissolving chitosan in acid solution, adding modified magnetic activated carbon, stirring and mixing evenly, adding NHS and EDC, stirring and activating, adding silk fibroin peptide, stirring and reacting, separating with a magnet, washing, and drying to obtain a modified magnetic activated carbon composite; S6. Preparation of modified chelating agent: Add the modified magnetic activated carbon composite into water, add phytic acid, β-cyclodextrin and dipotassium hydrogen phosphate, heat and stir to react, increase the temperature for hydrothermal reaction, separate with a magnet, wash and dry to obtain the modified chelating agent.

[0010] As a further improvement of the present invention, the alkali solution in step S1 is a 10-15wt% NaOH or KOH solution, the temperature of the hydrothermal reaction is 100-120°C, and the time is 2-4h; the mass ratio of graphene oxide and pretreated activated carbon in step S2 is 3-5:10, the power of the ultrasonic dispersion is 2000-2500W, and the time is 10-15min.

[0011] As a further improvement of the present invention, the mass ratio of the wrinkled activated carbon, ferric chloride, ferrous chloride and ammonia water in step S3 is 10:3.24:1.26:4-6, the temperature of the heating and stirring reaction is 80-90°C, the time is 3-5h, and the calcination temperature is 450-550°C, and the time is 1-2h.

[0012] As a further improvement of the present invention, the mass ratio of the magnetic activated carbon, tannic acid and catalyst in step S4 is 10:4-6:1-2, the catalyst is a Tris-HCl solution with a pH of 8.5-9.5, the temperature of the heating and stirring reaction is 45-55°C, and the time is 3-5h.

[0013] As a further improvement of the present invention, the acid solution in step S5 is 1-3wt% acetic acid or lactic acid solution, the mass ratio of chitosan, modified magnetic activated carbon, NHS, EDC and silk fibroin peptide is 5-7:12-15:1-2:1-2:2-3, the stirring reaction time is 10-12h, and the stirring activation time is 20-30min.

[0014] As a further improvement of the present invention, the mass ratio of the modified magnetic activated carbon composite, phytic acid, β-cyclodextrin and dipotassium hydrogen phosphate in step S6 is 10-15:4-6:3-5:0.5-1, the temperature of the heating and stirring reaction is 70-80°C, the time is 2-4h, and the temperature of the hydrothermal reaction is increased to 120-150°C, and the time is 7-10h.

[0015] The present invention further protects a method for preparing the above-mentioned filter membrane cleaning agent, which comprises the following steps: stirring and mixing a surfactant, a solubilizing agent, a pH adjusting agent and a chelating agent to obtain the filter membrane cleaning agent.

[0016] The present invention has the following beneficial effects: The present invention adopts alcohol cosolvent and surfactant cosolvent as cosolvents, strengthens the synergistic effect of the two, reduces the usage of the two, and improves the solubility effect; the cleaning agent prepared by the present invention has a low foaming rate, far meets the use standard, and has good stability, and no stratification, crystallization or precipitation occurs when placed in low temperature and high temperature environments; in addition, the cleaning agent has good wetting properties with the composite RO membrane, has an excellent cleaning effect on it, and can be widely used in filter membranes. Therefore, the present invention is a composite high-efficiency membrane cleaning agent with excellent stability and excellent cleaning effect on filter membranes.

[0017] The chelating agent of the present invention is a mixture of a modified chelating agent and a chemical chelating agent, wherein the modified chelating agent is a modified chelating agent prepared by coating activated carbon with graphene oxide, depositing magnetic ferroferric oxide, modifying the surface with tannic acid, loading chitosan and silk fibroin peptide, and reacting the surface with phytic acid and beta-cyclodextrin.

[0018] The present invention takes biomass activated carbon as the main body, has the advantages of wide raw material source, rich voids, large specific surface area, etc., and is easy to realize adsorption and separation of fine dust and other substances, so as to remove inorganic small particles on the surface of the filter membrane. After alkali solution pretreatment, the surface has a small amount of hydroxyl groups, which can form hydrogen bonds with the surface of graphene oxide to adsorb graphene oxide and load it on the surface. Graphene oxide is a single-layer structure and contains a large number of oxygen-containing functional groups, including epoxy bridges (-O-), hydroxyl groups (-OH), carboxyl groups (-COOH) and carbonyl groups (=O), and has better chemical stability and reactivity. After the spray drying process, smaller droplets have a larger specific surface area, can be dried faster, form finer particles, and form larger particles during the drying process. These particles may shrink and deform during the drying process to form a fold structure, and the further increased specific surface area of ​​the product is more conducive to realizing the chelating reaction and the adsorption of fine particles. At the same time, the oxygen-containing functional groups on the surface can complex ferric ions and ferrous ions, thereby realizing an in-situ reaction to promote the formation of magnetic ferroferric oxide, which is helpful for the removal and separation of the modified chelating agent. At the same time, it also increases the specific surface area of ​​the chelating agent and improves the adsorption capacity for small particles. The surface is modified by tannic acid coating. On the one hand, the organic structure of tannic acid can have an affinity with the filter membrane with a similar structure, causing it to adsorb near the filter membrane and react to the scale on the surface of the filter membrane, promoting the swelling and fluffing of the scale to form bubbles. At the same time, other components enter the interior of the scale, the surfactant can coat the scale inside, and the solubilizer promotes the dissolution of organic matter in the scale, thereby destroying, dispersing and dissolving the scale, achieving a good purification effect. On the other hand, tannic acid coating modification can also be coupled with chitosan and silk protein peptides, so that the chelating agent surface is rich in active groups such as amino, hydroxyl, and carboxyl groups, and can chelate and fix metal ions in water, such as calcium ions and magnesium ions, thereby effectively reducing the formation of scale, and can also neutralize and bridge charged particles in water to form stable flocs, and at the same time, can adsorb organic components such as proteins in water, reducing the formation of scale. The present invention further reacts with phytic acid and β-cyclodextrin on the surface, so that the rich phosphate radicals carried by phytic acid can also improve the scale crystal structure by forming a chelation effect, and chelate stable metal ions, thereby reducing the formation of scale and destroying the structure of scale, and the organic cavity of β-cyclodextrin can also fix organic components, reduce the deposition of organic scale components such as grease, etc., thereby more comprehensively contributing to the destruction and elimination of scale. At the same time, the modified chelating agent prepared by the present invention can also reduce the foaming property of the surfactant to a certain extent, and improve the stability of the cleaning agent.

[0019] The cleaning agent for the filter membrane prepared by the present invention has a good destroying and eliminating effect on the scale accumulation of the filter membrane, reduces the formation of scale, destroys the crystal structure of the scale, thereby promoting the swelling, fluffiness, dispersion and dissolution of the scale accumulation, thereby having a good cleaning effect. At the same time, it has good biocompatibility, is safe and environmentally friendly, has no destructive effect on the filter membrane, and after use, a simple rinsing can complete the scale removal effect. The use method is simple, the efficiency is high, and it has broad application prospects. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] NHS, N-hydroxysuccinimide; EDC, 1-ethyl-(3-dimethylaminopropyl)carbodiimide.

[0022] Preparation Example 1 Preparation of modified chelating agent Here’s how: S1. Pretreatment of activated carbon: 10 g of wood activated carbon was crushed, ball-milled for 1 h, added to 200 mL of 10 wt% NaOH solution, heated to 100 ° C, hydrothermally reacted for 2 h, centrifuged, washed, and dried to obtain pretreated activated carbon; S2. Preparation of creased activated carbon: 3 g of graphene oxide was added to 200 mL of water, 10 g of pretreated activated carbon was added, ultrasonic dispersion was performed at 2000 W for 10 min, and the creased activated carbon was obtained by spray drying; S3. Preparation of magnetic activated carbon: 10 g of creased activated carbon was added to 200 mL of water, 3.24 g of ferric chloride and 1.26 g of ferrous chloride were added under nitrogen protection, 4 g of ammonia water was added dropwise, heated to 80 ° C, stirred for 3 h, centrifuged, washed, dried, and calcined at 450 ° C for 1 h to obtain magnetic activated carbon; S4. Preparation of modified magnetic activated carbon: 10 g of magnetic activated carbon was added to 200 mL of water, 4 g of tannic acid and 1 g of catalyst were added, heated to 45 ° C, stirred for 3 h, separated by a magnet, washed, and dried to obtain modified magnetic activated carbon; The catalyst is a Tris-HCl solution with a pH of 8.5; S5. Preparation of modified magnetic activated carbon composite: 5 g chitosan was dissolved in 200 mL 1 wt% acetic acid solution, 12 g modified magnetic activated carbon was added, stirred and mixed for 10 min, 1 g NHS and 1 g EDC were added, stirred and activated for 20 min, 2 g silk fibroin peptide was added, stirred and reacted for 10 h, separated by magnet, washed, and dried to obtain a modified magnetic activated carbon composite; S6. Preparation of modified chelating agent: Add 10g modified magnetic activated carbon composite into 200mL water, add 4g phytic acid, 3g β-cyclodextrin and 0.5g dipotassium hydrogen phosphate, heat to 70℃, stir and react for 2h, heat to 120℃, hydrothermally react for 7h, separate with magnet, wash and dry to obtain modified chelating agent.

[0023] Preparation Example 2 Preparation of modified chelating agent Here’s how: S1. Pretreatment of activated carbon: 10 g of wood activated carbon was crushed, ball-milled for 1 h, added to 200 mL of 15 wt% KOH solution, heated to 120 ° C, hydrothermally reacted for 4 h, centrifuged, washed, and dried to obtain pretreated activated carbon; S2. Preparation of creased activated carbon: 5 g of graphene oxide was added to 200 mL of water, 10 g of pretreated activated carbon was added, ultrasonically dispersed at 2500 W for 15 min, and spray dried to obtain creased activated carbon; S3. Preparation of magnetic activated carbon: 10 g of creased activated carbon was added to 200 mL of water, and under nitrogen protection, 3.24 g of ferric chloride and 1.26 g of ferrous chloride were added, 6 g of ammonia water was added dropwise, and the mixture was heated to 90 ° C, stirred for 5 h, centrifuged, washed, dried, and calcined at 550 ° C for 2 h to obtain magnetic activated carbon; S4. Preparation of modified magnetic activated carbon: 10 g of magnetic activated carbon was added to 200 mL of water, 6 g of tannic acid and 2 g of catalyst were added, heated to 55 ° C, stirred for 5 h, separated by magnet, washed, and dried to obtain modified magnetic activated carbon; The catalyst is a Tris-HCl solution with a pH of 9.5; S5. Preparation of modified magnetic activated carbon composite: 7 g chitosan was dissolved in 200 mL 3 wt % lactic acid solution, 15 g modified magnetic activated carbon was added, stirred and mixed for 10 min, 2 g NHS and 2 g EDC were added, stirred and activated for 30 min, 3 g silk fibroin peptide was added, stirred and reacted for 12 h, separated by magnet, washed, and dried to obtain a modified magnetic activated carbon composite; S6. Preparation of modified chelating agent: Add 15g modified magnetic activated carbon composite into 200mL water, add 6g phytic acid, 5g β-cyclodextrin and 1g dipotassium hydrogen phosphate, heat to 80°C, stir and react for 4h, heat to 150°C, hydrothermally react for 10h, separate with a magnet, wash and dry to obtain a modified chelating agent.

[0024] Preparation Example 3 Preparation of modified chelating agent Here’s how: S1. Pretreatment of activated carbon: 10 g of wood activated carbon was crushed, ball-milled for 1 h, added to 200 mL of 12 wt% NaOH solution, heated to 110 ° C, hydrothermally reacted for 3 h, centrifuged, washed, and dried to obtain pretreated activated carbon; S2. Preparation of creased activated carbon: 4 g of graphene oxide was added to 200 mL of water, 10 g of pretreated activated carbon was added, ultrasonic dispersion was performed at 2250 W for 12 min, and the creased activated carbon was obtained by spray drying; S3. Preparation of magnetic activated carbon: 10 g of creased activated carbon was added to 200 mL of water, 3.24 g of ferric chloride and 1.26 g of ferrous chloride were added under nitrogen protection, 5 g of ammonia water was added dropwise, heated to 85 ° C, stirred for 4 h, centrifuged, washed, dried, and calcined at 500 ° C for 1.5 h to obtain magnetic activated carbon; S4. Preparation of modified magnetic activated carbon: 10 g of magnetic activated carbon was added to 200 mL of water, 5 g of tannic acid and 1.5 g of catalyst were added, heated to 50 ° C, stirred for 4 h, separated by magnet, washed, and dried to obtain modified magnetic activated carbon; The catalyst is a Tris-HCl solution with a pH of 9; S5. Preparation of modified magnetic activated carbon composite: 6 g chitosan was dissolved in 200 mL 2 wt% acetic acid solution, 13 g modified magnetic activated carbon was added, stirred and mixed for 10 min, 1.5 g NHS and 1.5 g EDC were added, stirred and activated for 25 min, 2.5 g silk fibroin peptide was added, stirred and reacted for 11 h, separated by magnet, washed, and dried to obtain a modified magnetic activated carbon composite; S6. Preparation of modified chelating agent: Add 12g of modified magnetic activated carbon composite into 200mL of water, add 5g of phytic acid, 4g of β-cyclodextrin and 0.7g of dipotassium hydrogen phosphate, heat to 75°C, stir and react for 3h, heat to 135°C, hydrothermally react for 8h, separate with a magnet, wash and dry to obtain a modified chelating agent.

[0025] Comparative Preparation Example 1 Compared with Example 3, the difference is that step S2 is not performed.

[0026] The details are as follows: S1. Pretreatment of activated carbon: 10 g of wood activated carbon was crushed, ball-milled for 1 h, added to 200 mL of 12 wt% NaOH solution, heated to 110 ° C, hydrothermally reacted for 3 h, centrifuged, washed, and dried to obtain pretreated activated carbon; S2. Preparation of magnetic activated carbon: 10 g of pretreated activated carbon was added to 200 mL of water, and under nitrogen protection, 3.24 g of ferric chloride and 1.26 g of ferrous chloride were added, 5 g of ammonia water was added dropwise, and the mixture was heated to 85 ° C, stirred for 4 h, centrifuged, washed, dried, and calcined at 500 ° C for 1.5 h to obtain magnetic activated carbon; S3. Preparation of modified magnetic activated carbon: 10 g of magnetic activated carbon was added to 200 mL of water, 5 g of tannic acid and 1.5 g of catalyst were added, heated to 50 ° C, stirred for 4 h, separated by magnet, washed, and dried to obtain modified magnetic activated carbon; The catalyst is a Tris-HCl solution with a pH of 9; S4. Preparation of modified magnetic activated carbon composite: 6 g chitosan was dissolved in 200 mL 2 wt% acetic acid solution, 13 g modified magnetic activated carbon was added, stirred and mixed for 10 min, 1.5 g NHS and 1.5 g EDC were added, stirred and activated for 25 min, 2.5 g silk fibroin peptide was added, stirred and reacted for 11 h, separated by magnet, washed, and dried to obtain a modified magnetic activated carbon composite; S5. Preparation of modified chelating agent: Add 12g modified magnetic activated carbon composite into 200mL water, add 5g phytic acid, 4g β-cyclodextrin and 0.7g dipotassium hydrogen phosphate, heat to 75°C, stir and react for 3h, heat to 135°C, hydrothermally react for 8h, separate with magnet, wash and dry to obtain modified chelating agent.

[0027] Comparative Preparation Example 2 Compared with Example 3, the difference is that step S3 is not performed.

[0028] The details are as follows: S1. Pretreatment of activated carbon: 10 g of wood activated carbon was crushed, ball-milled for 1 h, added to 200 mL of 12 wt% NaOH solution, heated to 110 ° C, hydrothermally reacted for 3 h, centrifuged, washed, and dried to obtain pretreated activated carbon; S2. Preparation of creased activated carbon: 4 g of graphene oxide was added to 200 mL of water, 10 g of pretreated activated carbon was added, ultrasonic dispersion was performed at 2250 W for 12 min, and the creased activated carbon was obtained by spray drying; S3. Preparation of modified magnetic activated carbon: 10 g of creased activated carbon was added to 200 mL of water, 5 g of tannic acid and 1.5 g of catalyst were added, heated to 50 ° C, stirred for 4 h, separated by magnet, washed, and dried to obtain modified magnetic activated carbon; The catalyst is a Tris-HCl solution with a pH of 9; S4. Preparation of modified magnetic activated carbon composite: 6 g chitosan was dissolved in 200 mL 2 wt% acetic acid solution, 13 g modified magnetic activated carbon was added, stirred and mixed for 10 min, 1.5 g NHS and 1.5 g EDC were added, stirred and activated for 25 min, 2.5 g silk fibroin peptide was added, stirred and reacted for 11 h, separated by magnet, washed, and dried to obtain a modified magnetic activated carbon composite; S5. Preparation of modified chelating agent: Add 12g modified magnetic activated carbon composite into 200mL water, add 5g phytic acid, 4g β-cyclodextrin and 0.7g dipotassium hydrogen phosphate, heat to 75°C, stir and react for 3h, heat to 135°C, hydrothermally react for 8h, separate with magnet, wash and dry to obtain modified chelating agent.

[0029] Comparative Preparation Example 3 Compared with Example 3, the difference is that step S4 is not performed.

[0030] The details are as follows: S1. Pretreatment of activated carbon: 10 g of wood activated carbon was crushed, ball-milled for 1 h, added to 200 mL of 12 wt% NaOH solution, heated to 110 ° C, hydrothermally reacted for 3 h, centrifuged, washed, and dried to obtain pretreated activated carbon; S2. Preparation of creased activated carbon: 4 g of graphene oxide was added to 200 mL of water, 10 g of pretreated activated carbon was added, ultrasonic dispersion was performed at 2250 W for 12 min, and the creased activated carbon was obtained by spray drying; S3. Preparation of magnetic activated carbon: 10 g of creased activated carbon was added to 200 mL of water, 3.24 g of ferric chloride and 1.26 g of ferrous chloride were added under nitrogen protection, 5 g of ammonia water was added dropwise, heated to 85 ° C, stirred for 4 h, centrifuged, washed, dried, and calcined at 500 ° C for 1.5 h to obtain magnetic activated carbon; S4. Preparation of modified magnetic activated carbon composite: 6 g chitosan was dissolved in 200 mL 2 wt% acetic acid solution, 13 g magnetic activated carbon was added, and the mixture was stirred for 10 min, 1.5 g NHS and 1.5 g EDC were added, and the mixture was stirred for activation for 25 min, 2.5 g silk fibroin peptide was added, and the mixture was stirred for reaction for 11 h, separated by magnet, washed, and dried to obtain a modified magnetic activated carbon composite; S5. Preparation of modified chelating agent: Add 12g modified magnetic activated carbon composite into 200mL water, add 5g phytic acid, 4g β-cyclodextrin and 0.7g dipotassium hydrogen phosphate, heat to 75°C, stir and react for 3h, heat to 135°C, hydrothermally react for 8h, separate with magnet, wash and dry to obtain modified chelating agent.

[0031] Comparative Preparation Example 4 Compared with Embodiment 3, the difference is that step S5 is not performed.

[0032] The details are as follows: S1. Pretreatment of activated carbon: 10 g of wood activated carbon was crushed, ball-milled for 1 h, added to 200 mL of 12 wt% NaOH solution, heated to 110 ° C, hydrothermally reacted for 3 h, centrifuged, washed, and dried to obtain pretreated activated carbon; S2. Preparation of creased activated carbon: 4 g of graphene oxide was added to 200 mL of water, 10 g of pretreated activated carbon was added, ultrasonic dispersion was performed at 2250 W for 12 min, and the creased activated carbon was obtained by spray drying; S3. Preparation of magnetic activated carbon: 10 g of creased activated carbon was added to 200 mL of water, 3.24 g of ferric chloride and 1.26 g of ferrous chloride were added under nitrogen protection, 5 g of ammonia water was added dropwise, heated to 85 ° C, stirred for 4 h, centrifuged, washed, dried, and calcined at 500 ° C for 1.5 h to obtain magnetic activated carbon; S4. Preparation of modified magnetic activated carbon: 10 g of magnetic activated carbon was added to 200 mL of water, 5 g of tannic acid and 1.5 g of catalyst were added, heated to 50 ° C, stirred for 4 h, separated by magnet, washed, and dried to obtain modified magnetic activated carbon; The catalyst is a Tris-HCl solution with a pH of 9; S5. Preparation of modified chelating agent: Add 12g modified magnetic activated carbon into 200mL water, add 5g phytic acid, 4g β-cyclodextrin and 0.7g dipotassium hydrogen phosphate, heat to 75°C, stir and react for 3h, heat to 135°C, hydrothermally react for 8h, separate with a magnet, wash and dry to obtain a modified chelating agent.

[0033] Comparative Preparation Example 5 Compared with the embodiment 3, the difference is that step S6 is not performed.

[0034] The details are as follows: S1. Pretreatment of activated carbon: 10 g of wood activated carbon was crushed, ball-milled for 1 h, added to 200 mL of 12 wt% NaOH solution, heated to 110 ° C, hydrothermally reacted for 3 h, centrifuged, washed, and dried to obtain pretreated activated carbon; S2. Preparation of creased activated carbon: 4 g of graphene oxide was added to 200 mL of water, 10 g of pretreated activated carbon was added, ultrasonic dispersion was performed at 2250 W for 12 min, and the creased activated carbon was obtained by spray drying; S3. Preparation of magnetic activated carbon: 10 g of creased activated carbon was added to 200 mL of water, 3.24 g of ferric chloride and 1.26 g of ferrous chloride were added under nitrogen protection, 5 g of ammonia water was added dropwise, heated to 85 ° C, stirred for 4 h, centrifuged, washed, dried, and calcined at 500 ° C for 1.5 h to obtain magnetic activated carbon; S4. Preparation of modified magnetic activated carbon: 10 g of magnetic activated carbon was added to 200 mL of water, 5 g of tannic acid and 1.5 g of catalyst were added, heated to 50 ° C, stirred for 4 h, separated by magnet, washed, and dried to obtain modified magnetic activated carbon; The catalyst is a Tris-HCl solution with a pH of 9; S5. Preparation of modified magnetic activated carbon composite: 6 g chitosan was dissolved in 200 mL 2 wt% acetic acid solution, 13 g modified magnetic activated carbon composite was added, and the mixture was stirred for 10 min. 1.5 g NHS and 1.5 g EDC were added, and the mixture was stirred for activation for 25 min. 2.5 g silk fibroin peptide was added, and the mixture was stirred for reaction for 11 h. The mixture was separated by magnet, washed, and dried to obtain a modified magnetic activated carbon composite, which is a modified chelating agent.

[0035] Example 1 The present embodiment provides a cleaning agent for a filter membrane, which is prepared from the following raw materials in parts by weight: 3 parts of a surfactant, 12 parts of sodium isopropyl sulfonate, 2 parts of sodium bicarbonate, and 2 parts of a chelating agent.

[0036] The chelating agent is a mixture of the modified chelating agent obtained in Preparation Example 1 and sodium gluconate, with a mass ratio of 10:3.

[0037] The surfactant is a mixture of decyl glucoside and anionic surfactant LAS, with a mass ratio of 1:0.5.

[0038] The preparation method comprises the following steps: stirring and mixing the surfactant, sodium isopropyl sulfonate, sodium bicarbonate and a chelating agent evenly to obtain a cleaning agent for a filter membrane.

[0039] Example 2 The present embodiment provides a cleaning agent for a filter membrane, which is prepared from the following raw materials in parts by weight: 15 parts of a surfactant, 40 parts of glycerol, 5 parts of sodium carbonate and 5 parts of a chelating agent.

[0040] The chelating agent is a mixture of the modified chelating agent obtained in Preparation Example 2 and sodium gluconate, with a mass ratio of 10:5.

[0041] The surfactant is a mixture of decyl glucoside and anionic surfactant LAS, with a mass ratio of 1:1.

[0042] The preparation method comprises the following steps: stirring and mixing the surfactant, glycerol, sodium carbonate and the chelating agent evenly to obtain the cleaning agent for the filter membrane.

[0043] Example 3 The present embodiment provides a cleaning agent for a filter membrane, which is prepared from the following raw materials in parts by weight: 10 parts of a surfactant, 25 parts of propylene glycol, 3 parts of potassium carbonate, and 3 parts of a chelating agent.

[0044] The chelating agent is a mixture of the modified chelating agent obtained in Preparation Example 3 and disodium ethylenediaminetetraacetate, with a mass ratio of 10:4.

[0045] The surfactant is a mixture of decyl glucoside and anionic surfactant LAS, with a mass ratio of 1:0.7.

[0046] The preparation method comprises the following steps: stirring and mixing the surfactant, propylene glycol, potassium carbonate and a chelating agent evenly to obtain a cleaning agent for a filter membrane.

[0047] Comparative Example 1 Compared with Example 3, the difference is that the modified chelating agent is prepared by Comparative Preparation Example 1.

[0048] Comparative Example 2 Compared with Example 3, the difference is that the modified chelating agent is prepared by Comparative Preparation Example 2.

[0049] Comparative Example 3 Compared with Example 3, the difference is that the modified chelating agent is prepared by Comparative Preparation Example 3.

[0050] Comparative Example 4 Compared with Example 3, the difference is that the modified chelating agent is prepared by Comparative Preparation Example 4.

[0051] Comparative Example 5 Compared with Example 3, the difference is that the modified chelating agent is prepared by Comparative Preparation Example 5.

[0052] Comparative Example 6 Compared with Example 3, the difference is that the chelating agent is disodium ethylenediaminetetraacetate.

[0053] Comparative Example 7 Compared with Example 3, the difference is that no solubilizing agent is added.

[0054] Test Example 1 The cleaning agents for the filter membranes prepared in Examples 1-3 of the present invention and Comparative Examples 6 and 7 were subjected to performance tests. The results are shown in Table 1.

[0055] (1) Foaming performance test Dilute the cleaning agent of the filter membrane with water to 100 mg / mL, stir evenly, the experimental temperature is 45±2℃, take 20mL of the aqueous solution and pour it into a 100mL stoppered measuring cylinder, then add 10mL of warm water, shake it up and down vigorously 25 times, record the foam height at this time, let it stand for 5 minutes, and record the foam height again. Repeat the test 3 times and take the average value.

[0056] (2) Stability performance test Place the cleaning agent in a low temperature (-5±2℃) for 24 hours and a high temperature environment (60±2℃) for 6 hours, then place it at room temperature to check whether it is uniform and whether there is any stratification, crystallization or precipitation.

[0057] (3) Contact angle performance test The smaller the contact angle, the better the wetting performance of the liquid on the solid surface. The contact angle of the cleaning agent of the polyamide composite RO membrane and the filter membrane was measured using a contact angle meter.

[0058] Table 1 As can be seen from the above table, the cleaning agents of the filter membranes prepared in Examples 1-3 of the present invention have low foaming heights, good stability, small contact angles, and good wettability. In Comparative Example 6, no modified chelating agent was added, and its foaming performance decreased. It can be seen that the modified chelating agent can reduce the foaming height to a certain extent and destroy the foam formation. In Comparative Example 7, no solubilizing agent was added, and the contact angle and foam height were significantly improved. It can be seen that the solubilizing agent can improve the wettability of the cleaning agent and, at the same time, destroy the formation of foam.

[0059] Test Example 2 The ultrafiltration equipment of Millipore Labscale TMTFF System was used. The molecular weight cut-off of the ultrafiltration membrane was 10KDa, the membrane material was PES, and the effective filtration area of ​​the membrane module was 50cm 2 , the ultrafiltration conditions are 0.2MPa, 70℃; the whole milk is ultrafiltered under the above conditions, and the membrane flux after contamination is measured at 180min, and the whole milk is of the same brand on the market; the cleaning agent of the filter membrane prepared by Examples 1-3 or Comparative Examples 1-7 of the present invention is prepared into an aqueous solution with a concentration of 0.5% for cleaning, and the overall cleaning time is controlled at 2h. After cleaning, the cleaning effect is tested, and the flux recovery rate WFR (water flux recovery) is used to represent it. The larger the WFR, the better the cleaning effect of the cleaning agent. The flux recovery rate (%) is calculated according to the following formula: Where Jwc is the pure water flux of the membrane after cleaning, L / m 2 ·h; Jwf is the pure water flux of the membrane after contamination, L / m 2·h; Jwi is the pure water flux of the membrane before contamination, L / m 2 ·h.

[0060] The results are shown in Table 2.

[0061] Table 2 It can be seen from the above table that the cleaning agents for the filter membranes prepared in Examples 1-3 of the present invention have a good cleaning effect on the ultrafiltration membrane.

[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A cleaning agent for a filter membrane, characterized in that: The invention is prepared from the following raw materials in parts by weight: 3-15 parts of a surfactant, 12-40 parts of a solubilizer, 2-5 parts of a pH regulator and 2-5 parts of a chelating agent. The chelating agent is a mixture of a modified chelating agent and a chemical chelating agent in a mass ratio of 10:3-5. The modified chelating agent is prepared by coating activated carbon with graphene oxide, depositing magnetic ferroferric oxide, modifying the surface with tannic acid, loading chitosan and silk protein peptide, and reacting the surface with phytic acid and beta-cyclodextrin.

2. The cleaning agent for the filter membrane according to claim 1, characterized in that: The surfactant is a mixture of decyl glucoside and anionic surfactant LAS, with a mass ratio of 1:0.5-1; the solubilizer is at least one of propylene glycol, sodium isopropyl sulfonate, and glycerol; the pH adjuster is at least one of potassium carbonate, potassium bicarbonate, sodium carbonate, sodium bicarbonate, and sodium hydroxide; and the chemical chelating agent is at least one of sodium gluconate, sodium gluconate heptanoate, ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetic acid, and tetrasodium glutamate diacetate.

3. The cleaning agent for the filter membrane according to claim 2, characterized in that: The preparation method of the modified chelating agent is as follows: S1. Pretreatment of activated carbon: crushing wood activated carbon, ball milling, adding to alkali solution, hydrothermal reaction, centrifugation, washing, drying, and obtaining pretreated activated carbon; S2. Preparation of wrinkled activated carbon: adding graphene oxide to water, adding pretreated activated carbon, ultrasonically dispersing uniformly, spray drying, and obtaining wrinkled activated carbon; S3. Preparation of magnetic activated carbon: adding folded activated carbon to water, adding ferric chloride and ferrous chloride under inert gas protection, adding ammonia water dropwise, heating and stirring the reaction, centrifuging, washing, drying, and calcining to obtain magnetic activated carbon; S4. Preparation of modified magnetic activated carbon: adding magnetic activated carbon to water, adding tannic acid and a catalyst, heating and stirring to react, separating with a magnet, washing, and drying to obtain modified magnetic activated carbon; S5. Preparation of modified magnetic activated carbon composite: dissolving chitosan in acid solution, adding modified magnetic activated carbon, stirring and mixing evenly, adding NHS and EDC, stirring and activating, adding silk fibroin peptide, stirring and reacting, separating with a magnet, washing, and drying to obtain a modified magnetic activated carbon composite; S6. Preparation of modified chelating agent: Add the modified magnetic activated carbon composite into water, add phytic acid, β-cyclodextrin and dipotassium hydrogen phosphate, heat and stir to react, increase the temperature for hydrothermal reaction, separate with a magnet, wash and dry to obtain the modified chelating agent.

4. The cleaning agent for the filter membrane according to claim 3, characterized in that: The alkali solution in step S1 is a 10-15wt% NaOH or KOH solution, the temperature of the hydrothermal reaction is 100-120°C, and the time is 2-4h; the mass ratio of graphene oxide and pretreated activated carbon in step S2 is 3-5:10, the power of the ultrasonic dispersion is 2000-2500W, and the time is 10-15min.

5. The cleaning agent for the filter membrane according to claim 3, characterized in that: The mass ratio of the creased activated carbon, ferric chloride, ferrous chloride and ammonia water in step S3 is 10: 3.24:1.26:4-6, the temperature of the heating and stirring reaction is 80-90°C, the time is 3-5h, the temperature of the calcination is 450-550°C, the time is 1-2h.

6. The cleaning agent for the filter membrane according to claim 3, characterized in that: The mass ratio of the magnetic activated carbon, tannic acid and catalyst in step S4 is 10:4-6:1-2, the catalyst is a Tris-HCl solution with a pH of 8.5-9.5, the temperature of the heating and stirring reaction is 45-55° C., and the time is 3-5 hours.

7. The cleaning agent for the filter membrane according to claim 3, characterized in that: The acid solution in step S5 is 1-3wt% acetic acid or lactic acid solution, the mass ratio of chitosan, modified magnetic activated carbon, NHS, EDC and silk fibroin peptide is 5-7:12-15:1-2:1-2:2-3, the stirring reaction time is 10-12h, and the stirring activation time is 20-30min.

8. The cleaning agent for the filter membrane according to claim 3, characterized in that: The mass ratio of the modified magnetic activated carbon composite, phytic acid, β-cyclodextrin and dipotassium hydrogen phosphate in step S6 is 10-15:4-6:3-5:0.5-1, the temperature of the heating and stirring reaction is 70-80°C, the time is 2-4h, and the temperature of the hydrothermal reaction is increased to 120-150°C, and the time is 7-10h.

9. A method for preparing a cleaning agent for a filter membrane according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: stirring and mixing a surfactant, a solubilizing agent, a pH adjusting agent and a chelating agent uniformly to prepare a cleaning agent for a filter membrane.

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