Fe 2+ Method for controlling membrane fouling by in-situ acid production of organic pollutants induced by H2O2 and applications thereof

Abstract

This invention discloses a Fe 2+ - Membrane fouling control methods and applications for H2O2-induced in-situ acid production from organic pollutants; determination of the hydrophilicity / hydrophobicity of dissolved organic pollutants in the water to be treated; determination of Fe 2+ The dosage ratio of Fe and H2O2; the determination of Fe based on the concentration of organic pollutants. 2+ The concentration range of H2O2 and background cations; first add background cations to the water to be treated, stir and homogenize, then add H2O2 and Fe in sequence. 2+ The reaction is carried out by stirring, inducing the in-situ generation of carboxyl groups from organic pollutants. The pH of the water to be treated is adjusted to neutral, and after settling, it is injected into the ultrafiltration system for filtration. This method solves the problems of large amounts of iron sludge and secondary pollution generated by traditional Fenton technology. By simultaneously regulating the size of organic pollutants and their interaction forces on the membrane surface through the synergistic effect of oxidation and coagulation, effective control of membrane fouling is achieved.

Description

Technical Field

[0001] This invention belongs to the field of ultrafiltration membrane fouling control technology, and mainly relates to a Fe 2+ -Membrane fouling control methods and applications for in-situ acid production of organic pollutants induced by H2O2. Background Technology

[0002] Ultrafiltration technology, with its advantages of high efficiency, energy saving, and no secondary pollution, is widely used in wastewater treatment and resource utilization. However, in actual operation, dissolved organic matter such as humic substances, proteins, and polysaccharides, which are commonly found in the water to be treated, can easily cause a significant decline in the permeability of ultrafiltration membranes, i.e., membrane fouling. This is a major bottleneck restricting the further promotion and application of ultrafiltration technology. Numerous researchers have focused on elucidating the mechanism of membrane fouling, and most studies have found that increasing the size of organic pollutants in the water to be treated and weakening the forces exerted by organic pollutants on the membrane surface are effective means to control ultrafiltration membrane fouling.

[0003] Among various membrane fouling control technologies, coagulation and oxidation pretreatment are effective strategies for controlling the size of organic pollutants and the intensity of their interactions at the membrane interface, respectively. However, coagulation or oxidation pretreatment alone cannot simultaneously ensure an increase in the size of organic pollutants and a weakening of their interactions at the membrane surface, leading to the risk of exacerbating organic fouling. In contrast, Fenton technology combines coagulation and oxidation functions. It can promote the aggregation of organic pollutants into large aggregates and alter the surface chemical properties of organic pollutants through oxidation, thereby affecting the intensity of their interactions at the membrane interface. This makes it an effective means of controlling the size of organic pollutants and the intensity of their interactions at the membrane surface.

[0004] As early as 2006, researchers investigated the impact of Fenton pretreatment on membrane fouling behavior in membrane bioreactors. Subsequently, different researchers examined the membrane fouling characteristics before and after Fenton pretreatment for specific industrial wastewaters such as landfill leachate, food processing, and dyeing wastewater. The results all confirmed that Fenton pretreatment is an effective technical strategy for mitigating the rate of organic pollutant fouling in membranes. However, using Fenton technology for membrane fouling control faces several key technical challenges: First, the pH of the water to be treated needs to be adjusted to acidity, which not only increases operating and investment costs but also raises the requirements for the membrane module's resistance to acid corrosion. Second, the Fenton pretreatment process involves the introduction of a large amount of Fenton reagent to achieve the mineralization or precipitation of organic pollutants, accompanied by the generation of large amounts of iron sludge and the introduction of iron pollution into the effluent. These shortcomings fundamentally limit the practical application of traditional Fenton technology in the field of membrane fouling control. Therefore, it is still necessary to continue developing new methods to address the shortcomings of existing technologies, achieving simultaneous control of the size of organic pollutants and the intensity of their interactions at the membrane interface, and thus controlling organic fouling in ultrafiltration membranes. Summary of the Invention

[0005] Based on the key technical problems faced by traditional Fenton technology in the field of membrane organic pollution control, the purpose of this invention is to provide a Fe 2+ A membrane fouling control method based on H2O2-induced in-situ acid production from organic pollutants involves adding trace amounts of Fe2O3 without providing an acidic pH environment. 2+ By combining H2O2 with reaction process control, the size of organic pollutants and their interaction forces on the membrane surface can be directionally regulated through the synergistic effect of oxidation and coagulation, thereby achieving effective control of membrane fouling.

[0006] The present invention is achieved through the following technical solution.

[0007] This invention provides a Fe 2+ -Membranes fouling control methods for H2O2-induced in-situ acid production from organic pollutants include:

[0008] Organic pollutants in the water body to be treated are separated, and the hydrophilicity / hydrophobicity contact angle of the separated organic pollutants is measured. Based on the hydrophilicity / hydrophobicity of the organic pollutants in the water body to be treated, the Fe... 2+ The dosage ratio of H2O2;

[0009] Further, based on the dissolved organic matter (DOC) concentration in the water to be treated, the Fe was determined. 2+ The concentration range of H2O2 and background cations;

[0010] First, background cations are added to the water to be treated and stirred to homogenize it. Then, H2O2 and Fe are added sequentially. 2+The mixture was stirred and reacted for a certain period of time, and the organic pollutants were induced to produce carboxyl groups in situ through oxidation.

[0011] The pH of the solution was further adjusted to neutral to terminate the oxidation reaction. The solution was allowed to stand for 5-10 minutes to promote the aggregation of organic pollutants, and then injected into an ultrafiltration system for filtration.

[0012] Preferably, when the hydrophilic contact angle of the organic pollutants in the water to be treated is greater than 60°, Fe 2+ The mass ratio of H2O2 to H2O2 is 1:1 to 1:3.4;

[0013] When the hydrophilic contact angle of organic pollutants in the water to be treated is less than 60°, Fe 2+ The mass ratio of H2O2 to H2O2 is 1:0.34-1:1.4.

[0014] Preferably, the concentration of dissolved organic matter (DOC) in the water to be treated and H2O2 satisfy the following relationship:

[0015] H2O2(mg / L)=(0.2-1.7)×DOC(mg / L).

[0016] Preferably, the concentration of dissolved organic matter (DOC) in the water to be treated is related to the Fe... 2+ The following relationship must be satisfied:

[0017] Fe 2+ (mg / L)=(0.25-0.9)×DOC (mg / L).

[0018] The Fe 2+ For Fe 2+ Chloride or sulfate salts.

[0019] Preferably, the concentration of dissolved organic matter (DOC) in the water to be treated and the amount of background cations added satisfy the following relationship: 1 mmol of background cations with an ionic strength is required for every 1 mg of DOC.

[0020] Preferably, the background cations include Na. + Mg 2+ and Ca 2+ The ionic strength addition ratio of the three satisfies: Na + :Mg 2+ :Ca 2+ =4:3:3.

[0021] Na + Mg 2+ and Ca 2+ for Na + Mg 2+ and Ca 2+ Chloride or sulfate salts.

[0022] Preferably, in the stage of in-situ carboxylation of induced organic pollutants, background cations are first added to the water to be treated and stirred for 0.5-1.0 min, followed by the addition of H2O2, and after stirring and homogenization for 1-3 min, Fe is added. 2+ Stir and homogenize, and monitor the pH of the aqueous solution online. When the pH drops to 3-5, continue stirring for 3-10 minutes. Adjust the pH of the resulting solution to neutral and let it stand for 5-10 minutes.

[0023] The present invention, by adopting the above technical solution, has the following beneficial effects:

[0024] 1. The present invention provides a Fe 2+ The membrane fouling control method based on H2O2-induced in-situ acid production from organic pollutants involves adding trace amounts of Fe2O3 without providing an acidic pH environment. 2+ By combining H2O2 with reaction process control, the size of organic pollutants and the intensity of their interactions at the membrane interface can be directionally regulated, thereby achieving membrane fouling control.

[0025] 2. This invention first induces the initial oxidation of organic pollutants to form carboxyl groups. The deprotonation of carboxyl groups leads to the gradual formation of acidic conditions, thereby promoting the continuous oxidation of organic pollutants and forming an internal cycle. On the one hand, it weakens the overall interaction force of organic pollutants on the membrane surface, and on the other hand, it promotes the aggregation of organic pollutants to form large-sized aggregates. By regulating the internal reaction of organic pollutants through external factors, the size of organic pollutants and the strength of their interaction force at the membrane interface can be simultaneously regulated.

[0026] 3. Compared with traditional Fenton technology, the Fe provided by this invention... 2+ The H2O2-induced in-situ acidification of organic pollutants in membrane fouling control method can induce the in-situ production of carboxyl groups from organic pollutants without adjusting the water body to acidic conditions. This promotes the synergistic effect of oxidation and coagulation, and by changing the physicochemical properties of pollutants, it affects the adsorption and accumulation behavior of organic pollutants on the membrane surface and the structural characteristics of the adsorption layer. Ultimately, within the same operating time, the membrane flux decay rate is reduced by 30%-65%, and the membrane flux recovery rate after physical cleaning reaches more than 60%, effectively achieving membrane fouling control.

[0027] 4. This invention relates to Fe 2+-H2O2 induces in-situ acid production of organic pollutants. By controlling the addition of background cations, reaction time, and reaction environment conditions, the electrostatic repulsion between organic pollutants due to the formation of carboxyl groups is weakened. At the same time, the complexation, coordination, and bridging effects between polyvalent iron and organic pollutants are strengthened, effectively combining the added iron with the organic pollutants. This not only promotes the aggregation of organic pollutants but also avoids the secondary pollution problem caused by the loss of iron during membrane separation. Attached Figure Description

[0028] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, do not constitute an undue limitation of the invention. In the drawings:

[0029] Figure 1 For Fe 2+ The fouling behavior of protein pollutants on PVDF ultrafiltration membranes before and after -H2O2 (1:1.9) induced treatment.

[0030] Figure 2 For Fe 2+ The fouling behavior of protein pollutants on PVDF ultrafiltration membranes before and after H2O2 (1:3.4) induced treatment.

[0031] Figure 3 For Fe 2+ -H2O2 (1:1) induces the fouling behavior of humic pollutants on PVDF ultrafiltration membranes before and after treatment.

[0032] Figure 4 For Fe 2+ The fouling behavior of humic pollutants on PVDF ultrafiltration membranes before and after the -H2O2 (1:3.4) induced treatment.

[0033] Figure 5 For Fe 2+ The fouling behavior of polysaccharide pollutants on polyethersulfone ultrafiltration membranes before and after H2O2 (1:1.4) induction treatment.

[0034] Figure 6 For Fe 2+ The fouling behavior of polysaccharide pollutants on PVDF ultrafiltration membranes before and after H2O2 (1:0.34) induced treatment. Detailed Implementation

[0035] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The illustrative embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

[0036] An embodiment of the present invention provides a Fe 2+ -Membranes fouling control methods for H2O2-induced in-situ acid production from organic pollutants include:

[0037] Step 1: Filtration technology is used to separate organic pollutants from the water to be treated onto the surface of the filter media, forming a uniform pollutant layer, which is then vacuum dried. Afterwards, a contact angle meter is used to characterize the hydrophilicity and hydrophobicity of the organic pollutants. When the hydrophilic contact angle of the organic pollutants is greater than 60°, Fe... 2+ The mass ratio of Fe to H2O2 is 1:1 to 1:3.4; when the hydrophilic contact angle of organic pollutants in the water to be treated is less than 60°, Fe 2+ The mass ratio of H2O2 added is 1:0.34-1:1.4.

[0038] In this embodiment, Fe 2+ Add chloride or sulfate salts.

[0039] Step 2: The concentration of dissolved organic matter (DOC) in the water to be treated is determined using a total organic carbon analyzer, thereby determining the Fe content. 2+ The addition range is (0.25-0.9)×DOC(mg / L); the addition range of H2O2 is (0.2-1.7)×DOC(mg / L); the background cation addition range is 1 mmol of background cation with an ionic strength per 1 mg DOC.

[0040] Among them, background cations include Na + Mg 2+ and Ca 2+ The ionic strength addition ratio satisfies: Na + :Mg 2+ :Ca 2+ =4:3:3.

[0041] In this embodiment, Na + Mg 2+ and Ca 2+ Take Na + Mg 2+ and Ca 2+ Chloride or sulfate salts are added.

[0042] 3) First, add background cations to the water to be treated and stir for 0.5-1.0 min, then add H2O2, stir and homogenize for 1-3 min, and then add Fe. 2+ Stir and homogenize, and monitor the pH of the aqueous solution online. When the pH drops to 3-5, continue stirring for 3-10 minutes. Further adjust the pH of the solution to neutral to terminate the oxidation reaction, let it stand for 5-10 minutes to promote the aggregation of organic pollutants, and then inject it into an ultrafiltration system for membrane filtration.

[0043] The present invention will be further described in detail below through specific embodiments.

[0044] Example 1

[0045] Taking the operation of PVDF ultrafiltration membrane to treat simulated wastewater containing protein-based organic pollutants as an example

[0046] 1) Filtration technology was used to separate organic pollutants from the water to be treated onto the surface of the filter media, forming a uniform pollutant layer, which was then vacuum dried. Subsequently, a contact angle meter was used to measure the hydrophilic contact angle of the organic pollutants, which was found to be 63°. The Fe... 2+ The mass ratio of Fe to H2O2 added is 1:1.9; 2+ Chloride salts.

[0047] 2) The dissolved organic matter (DOC) concentration in the water to be treated was determined to be 10 mg / L using a total organic carbon analyzer. Based on this, the Fe... 2+ The dosage range is 9 mg / L, corresponding to a dosage ratio of 17 mg / L for H2O2; the background cation intensity is 10 mmol, where Na... + Mg 2+ and Ca 2+ The ionic strength dosages were 4 mmol, 3 mmol, and 3 mmol, respectively; Na + Mg 2+ and Ca 2+ Take Na + Mg 2+ and Ca 2+ Chloride salts were added.

[0048] 3) First, add the background cations determined in step 1) to the water to be treated and stir for 1.0 min. Then, add 17 mg / L of H2O2, stir and homogenize for 3 min, and then add 9 mg / L of Fe. 2+ The mixture was stirred and homogenized, and the pH of the aqueous solution was monitored online. When the pH dropped to 4, the reaction was stirred for another 7 minutes. The pH of the solution was then adjusted to neutral to terminate the oxidation reaction. After standing for 10 minutes, the solution was injected into a PVDF membrane ultrafiltration system for filtration.

[0049] like Figure 1 As shown, within the same operating time, the membrane flux decay rate without pretreatment was 89%, Fe 2+ After H2O2-induced treatment, the membrane flux decline rate was 24%, meaning the membrane fouling rate decreased by 65%. Meanwhile, after physical cleaning, the membrane flux recovery rate increased from 19% to 92%, and the degree of irreversible membrane fouling decreased by 73%.

[0050] Example 2

[0051] Taking the operation of PVDF ultrafiltration membrane to treat simulated wastewater containing protein-based organic pollutants as an example

[0052] 1) Filtration technology was used to separate organic pollutants from the water to be treated onto the surface of the filter media, forming a uniform pollutant layer, which was then vacuum dried. Subsequently, a contact angle meter was used to measure the hydrophilic contact angle of the organic pollutants, which was found to be 63°. The Fe... 2+ The mass ratio of Fe to H2O2 is 1:3.4; in this embodiment, Fe 2+ Add sulfate.

[0053] 2) The dissolved organic matter (DOC) concentration in the water to be treated was determined to be 10 mg / L using a total organic carbon analyzer. Based on this, the Fe... 2+ The dosage range is 5 mg / L, corresponding to a dosage ratio of 17 mg / L for H2O2; the background cation intensity is 10 mmol, where Na... + Mg 2+ and Ca 2+ The ionic strength dosages were 4 mmol, 3 mmol, and 3 mmol, respectively; in this example, Na... + Mg 2+ and Ca 2+ Take Na + Mg 2+ and Ca 2+ Sulfate was added.

[0054] 3) First, add the background cations determined in step 1) to the water to be treated and stir for 1.0 min. Then, add 17 mg / L of H2O2, stir and homogenize for 3 min, and then add 5 mg / L of Fe. 2+ The mixture was stirred and homogenized, and the pH of the aqueous solution was monitored online. When the pH dropped to 5, the reaction was stirred for another 10 minutes. The pH of the solution was then adjusted to neutral to terminate the oxidation reaction. After standing for 10 minutes, the solution was injected into a PVDF membrane ultrafiltration system for filtration.

[0055] like Figure 2 As shown, within the same operating time, the membrane flux decay rate without pretreatment was 89%, Fe 2+ After H2O2-induced treatment, the membrane flux decline rate was 50%, meaning the membrane fouling rate decreased by 39%. Meanwhile, after physical cleaning, the membrane flux recovery rate increased from 19% to 60%, and the irreversible fouling rate decreased by 41%.

[0056] Example 3

[0057] Taking the operation of PVDF ultrafiltration membrane to treat simulated wastewater containing humic organic pollutants as an example

[0058] 1) Filtration technology was used to separate organic pollutants from the water to be treated onto the surface of the filter media, forming a uniform pollutant layer, which was then vacuum dried. Subsequently, a contact angle meter was used to measure the hydrophilic contact angle of the organic pollutants, which was found to be 76°. The Fe...2+ The mass ratio of Fe to H2O2 is 1:1; in this embodiment, Fe 2+ Add with chloride salts.

[0059] 2) The dissolved organic matter (DOC) concentration in the water to be treated was determined to be 10 mg / L using a total organic carbon analyzer. Based on this, the Fe... 2+ The dosage range is 3.4 mg / L, corresponding to a dosage ratio of 3.4 mg / L for H2O2; the background cation intensity is 10 mmol, where Na... + Mg 2+ and Ca 2+ The ionic strength dosages were 4 mmol, 3 mmol, and 3 mmol, respectively; in this example, Na... + Mg 2+ and Ca 2+ Take Na + Mg 2+ and Ca 2+ Chloride salts were added.

[0060] 3) First, add the background cations determined in step 1) to the water to be treated and stir for 0.5 min. Then, add 3.4 mg / L of H2O2, stir and homogenize for 2 min, and then add 3.4 mg / L of Fe. 2+ The mixture was stirred and homogenized, and the pH of the aqueous solution was monitored online. When the pH dropped to 3, the reaction was stirred for another 3 minutes. The pH of the solution was then adjusted to neutral to terminate the oxidation reaction. After standing for 10 minutes, the solution was injected into a PVDF membrane ultrafiltration system for filtration.

[0061] like Figure 3 As shown, within the same operating time, the membrane flux decay rate without pretreatment was 83%, and Fe... 2+ After H2O2-induced treatment, the membrane flux decline rate was 40%, meaning the membrane fouling rate decreased by 43%. Meanwhile, after physical cleaning, the membrane flux recovery rate increased from 26% to 98%, and the irreversible fouling rate decreased by 72%.

[0062] Example 4

[0063] Taking the operation of PVDF ultrafiltration membrane to treat simulated wastewater containing humic organic pollutants as an example

[0064] 1) Filtration technology was used to separate organic pollutants from the water to be treated onto the surface of the filter media, forming a uniform pollutant layer, which was then vacuum dried. Subsequently, a contact angle meter was used to measure the hydrophilic contact angle of the organic pollutants, which was found to be 76°. The Fe... 2+ The mass ratio of Fe to H2O2 is 1:3.4; in this embodiment, Fe 2+ Add sulfate.

[0065] 2) The dissolved organic matter (DOC) concentration in the water to be treated was determined to be 8 mg / L using a total organic carbon analyzer. Based on this, the Fe... 2+ The dosage range is 4 mg / L, corresponding to a dosage ratio of 13.6 mg / L for H2O2; the background cation intensity is 8 mmol, where Na... + Mg 2+ and Ca 2+ The ionic strength dosages were 3.2 mmol, 2.4 mmol, and 2.4 mmol, respectively; in this embodiment, Na... + Mg 2+ and Ca 2+ Take Na + Mg 2+ and Ca 2+ Sulfate was added.

[0066] 3) First, add the background cations determined in step 1) to the water to be treated and stir for 0.5 min. Then, add 13.6 mg / L of H2O2, stir and homogenize for 1 min, and then add 4 mg / L of Fe. 2+ The mixture was stirred and homogenized, and the pH of the aqueous solution was monitored online. When the pH dropped to 5, the reaction was stirred for another 10 minutes. The pH of the solution was then adjusted to neutral to terminate the oxidation reaction. After standing for 10 minutes, the solution was injected into a PVDF membrane ultrafiltration system for filtration.

[0067] like Figure 4 As shown, within the same operating time, the membrane flux decay rate without pretreatment was 83%, and Fe... 2+ After H2O2-induced treatment, the membrane flux decline rate was 40%, meaning the membrane fouling rate decreased by 43%. Meanwhile, after physical cleaning, the membrane flux recovery rate increased from 26% to 80%, and the irreversible fouling rate decreased by 54%.

[0068] Example 5

[0069] Taking the treatment of polysaccharide organic pollutants in simulated wastewater using polyethersulfone ultrafiltration membrane as an example

[0070] 1) Filtration technology was used to separate organic pollutants from the water to be treated onto the surface of the filter media, forming a uniform pollutant layer, which was then vacuum dried. Subsequently, a contact angle meter was used to measure the hydrophilic contact angle of the organic pollutants, which was found to be 34°. The Fe... 2+ The mass ratio of Fe to H2O2 is 1:1.4; in this embodiment, Fe 2+ Add sulfate.

[0071] 2) The dissolved organic matter (DOC) concentration in the water to be treated was determined to be 5 mg / L using a total organic carbon analyzer. Based on this, the Fe... 2+The dosage range is 2.5 mg / L, corresponding to a dosage ratio of 3.5 mg / L for H2O2; the background cation intensity is 5 mmol, where Na... + Mg 2+ and Ca 2+ The ionic strength dosages were 2 mmol, 1.5 mmol, and 1.5 mmol, respectively; in this example, Na... + Mg 2+ and Ca 2+ Take Na + Mg 2+ and Ca 2+ Sulfate was added.

[0072] 3) First, add the background cations determined in step 1) to the water to be treated and stir for 1 min. Then, add 3.5 mg / L of H2O2, stir and homogenize for 3 min, and then add 2.5 mg / L of Fe. 2+ The mixture was stirred and homogenized, and the pH of the aqueous solution was monitored online. When the pH dropped to 5, the reaction was stirred for another 10 minutes. The pH of the solution was then adjusted to neutral to terminate the oxidation reaction. After standing for 5 minutes, the solution was injected into a polyethersulfone ultrafiltration membrane system for filtration.

[0073] like Figure 5 As shown, within the same operating time, the membrane flux decay rate without pretreatment was 94%, and Fe... 2+ After H2O2-induced treatment, the membrane flux decline rate was 32%, meaning the membrane fouling rate decreased by 62%. Meanwhile, after physical cleaning, the membrane flux recovery rate increased from 12% to 98%, and the irreversible fouling rate decreased by 86%.

[0074] Example 6

[0075] Taking the operation of PVDF ultrafiltration membrane to treat polysaccharide organic pollutants in simulated wastewater as an example

[0076] 1) Filtration technology was used to separate organic pollutants from the water to be treated onto the surface of the filter media, forming a uniform pollutant layer, which was then vacuum dried. Subsequently, a contact angle meter was used to measure the hydrophilic contact angle of the organic pollutants, which was found to be 34°. The Fe... 2+ The mass ratio of Fe to H2O2 is 1:0.34; in this embodiment, Fe 2+ Add with chloride salts.

[0077] 2) The dissolved organic matter (DOC) concentration in the water to be treated was determined to be 20 mg / L using a total organic carbon analyzer. Based on this, the Fe... 2+ The dosage range is 6 mg / L, corresponding to a dosage ratio of 2.04 mg / L for H2O2; the background cation intensity is 20 mmol, where Na... + Mg2+ and Ca 2+ The ionic strength dosages were 8 mmol, 6 mmol, and 6 mmol, respectively; in this embodiment, Na... + Mg 2+ and Ca 2+ Take Na + Mg 2+ and Ca 2+ Chloride salts were added.

[0078] 3) First, add the background cations determined in step 1) to the water to be treated and stir for 1 min. Then, add 2.04 mg / L of H2O2, stir and homogenize for 3 min, and then add 6 mg / L of Fe. 2+ The mixture was stirred and homogenized, and the pH of the aqueous solution was monitored online. When the pH dropped to 3, the reaction was stirred for another 4 minutes. The pH of the solution was then adjusted to neutral to terminate the oxidation reaction. After standing for 5 minutes, the solution was injected into a PVDF ultrafiltration membrane system for filtration.

[0079] like Figure 6 As shown, within the same operating time, the membrane flux decay rate without pretreatment is 90%, Fe 2+ After H2O2-induced treatment, the membrane flux decline rate was 57%, meaning the membrane fouling rate decreased by 33%. Meanwhile, after physical cleaning, the membrane flux recovery rate increased from 23% to 87%, and the irreversible fouling rate decreased by 64%.

[0080] As can be seen from the above embodiments, compared with organic pollutants without any pretreatment, the Fe of the present invention... 2+ Following H2O2-induced in-situ acidification pretreatment of organic pollutants, the membrane flux decline rate was at most 57%, decreasing to at least 33%. After physical cleaning, the membrane flux recovery rate was at least 60%, and the irreversible fouling rate was reduced by at least 41%. This effectively slowed down the membrane fouling rate and the extent of irreversible fouling, which is of great significance for controlling energy consumption and operating costs caused by membrane fouling in actual operation. The method of this invention has broad application prospects in the field of wastewater treatment engineering.

[0081] This invention is not limited to the above embodiments. Based on the technical solutions disclosed in this invention, those skilled in the art can make some substitutions and modifications to some of the technical features without creative effort, and all such substitutions and modifications are within the protection scope of this invention.

Claims

1. A Fe 2+ A membrane fouling control method for H2O2-induced in-situ acid production from organic pollutants, characterized in that... include: a) Separate organic pollutants from the water body to be treated, determine the hydrophilicity / hydrophobicity contact angle of the separated organic pollutants, and determine the Fe... 2+ The addition ratio of H2O2; Determine Fe 2+ The addition ratio of H2O2 satisfies: When the hydrophilic contact angle of organic pollutants in the water to be treated is greater than 60°, Fe 2+ The mass ratio of H2O2 to H2O2 is 1:1 to 3.

4. When the hydrophilic contact angle of organic pollutants in the water to be treated is less than 60°, Fe 2+ The mass ratio of H2O2 to H2O2 is 1:0.34 to 1.4; b) Determine the concentration of dissolved organic matter in the water to be treated, and determine the Fe... 2+ The concentration range of H2O2 and background cations; The concentrations of dissolved organic matter (DOC) and H2O2 in the water to be treated, when added at a dosage of mg / L, satisfy the following: H2O2 = (0.2–1.7) × DOC; The concentrations of dissolved organic matter (DOC) and Fe in the water to be treated 2+ According to the dosage in mg / L, the following needs are met: Fe 2+ It is (0.25~0.9)×DOC; The background cations include Na. + Mg 2+ and Ca 2+ Na + Mg 2+ and Ca 2+ The ionic strength addition ratio of the three is 4:3:3; The concentration of dissolved organic matter (DOC) in the water to be treated satisfies the following relationship with the amount of background cations added: for every 1 mg / L of DOC, add 1 mmol / L of background cations with an ionic strength. c) First, add background cations to the water to be treated, then add H2O2 and continue stirring and homogenizing for 1 min to 3 min, then add Fe. 2+ Stir and homogenize. When the pH drops to 3-5, continue stirring for 3-10 minutes to induce the in-situ generation of carboxyl groups from organic pollutants through oxidation. d) Adjust the pH of the resulting solution to neutral to terminate the oxidation reaction, let it stand, and then inject it into an ultrafiltration system for filtration.

2. The membrane fouling control method according to claim 1, characterized in that, The Fe 2+ For Fe 2+ Chloride or sulfate salts.

3. The membrane fouling control method according to claim 1, characterized in that, Na + Mg 2+ and Ca 2+ for Na + Mg 2+ and Ca 2+ Chloride or sulfate salts.

4. The membrane fouling control method according to claim 1, characterized in that, After adding the background cation and stirring and homogenizing for 0.5 min to 1 min, add H2O2 and continue stirring and homogenizing for 1 min to 3 min, then add Fe. 2+ Stir and homogenize. When the pH drops to 3-5, continue stirring for 3-10 minutes. Adjust the pH of the resulting solution to neutral and let it stand for 5-10 minutes.

5. The application of the membrane fouling control method according to any one of claims 1 to 4 in the field of wastewater treatment engineering.

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