CN108014650B

CN108014650B - Sewage treatment method

Info

Publication number: CN108014650B
Application number: CN201610930380.8A
Authority: CN
Inventors: 赵锐; 马欣
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petrochemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petrochemical Corp
Priority date: 2016-10-31
Filing date: 2016-10-31
Publication date: 2020-01-10
Anticipated expiration: 2036-10-31
Also published as: CN108014650A

Abstract

The invention discloses an intelligent membrane and a preparation method thereof, a membrane assembly, a membrane bioreactor and application thereof. The invention also discloses a method for intercepting microorganisms in water by adopting the intelligent membrane or membrane component and a sewage treatment method by adopting the membrane-bioreactor. Compared with the existing antimicrobial membrane, the intelligent membrane can sense the condition and the area of the membrane polluted by microorganisms, pertinently treat the polluted area, and can automatically stop the function after the pollution is relieved; the activity and the quantity of microorganisms in adjacent areas (such as a biochemical reactor) can not be killed or inhibited, the influence on biochemical reaction is small, and the method can be applied to most water treatment environments.

Description

Sewage treatment method

Technical Field

The invention relates to an intelligent membrane, a preparation method and application thereof, and also relates to a membrane component, a membrane-bioreactor and application thereof.

Background

With the progress of membrane materials and membrane modules, membrane separation technology has become one of the core technologies in the field of water purification and sewage treatment, and is used for intercepting pollutants such as microorganisms and suspended particles in water. During the use process, microorganisms trapped by the membrane can be attached to the surface and the pores of the membrane, and are easy to breed and propagate, so that the pores of the membrane are blocked, the flux of the membrane is rapidly reduced, the cleaning frequency of the membrane is increased, and the service life of the membrane is shortened due to the formed irreversible blockage. Thus, microbial contamination of membranes is a major problem facing the application of membrane technology.

At present, the means for relieving the microbial pollution mainly comprises introducing a hydrophilic material into a membrane material, improving the hydrophilicity of the membrane and improving the surface energy, thereby reducing the membrane pollution; antibacterial agents such as antibiotics, polycations, nano inorganic materials and the like are added on the surface of the membrane or in the material to inhibit or kill microorganisms on the surface of the membrane and around the surface of the membrane; or a combination of both methods and reinforcement. Common materials are polypyridine salts, polyquaternary ammonium salts, nano silver simple substances or silver-based compounds (such as CN104353366A and CN104014256A), carbon nanotubes (such as CN102008908A), titanium dioxide (such as CN104117291A) and the like.

However, when the above membrane is used in a novel membrane-biological process such as a Membrane Bioreactor (MBR), a bubble-free aeration biochemical reactor, and a microorganism culture apparatus, the sterilization or bacteriostatic properties of the membrane material may also affect the activity and quantity of microorganisms due to frequent contact between the microorganisms in the reactor and the high-density packed membrane, thereby reducing the efficiency of the bioreactor, and even destroying the biochemical performance.

Therefore, there is a need for an intelligent solution that can determine microbial contamination of membranes, generate responses in a targeted manner, and at the same time, not affect the microorganisms required for the process.

Disclosure of Invention

The invention aims to overcome the technical problems that the activity and the quantity of microorganisms are influenced by the sterilization or bacteriostasis property of a membrane material adopted by the existing antimicrobial membrane, so that the efficiency of a bioreactor is reduced, and even the biochemical performance is damaged, and provides an intelligent membrane which not only can effectively resist the microbial pollution, but also has little influence on the biochemical process.

According to a first aspect of the invention, there is provided a smart film comprising a film matrix, and a dispersion dispersed in the film matrix, the dispersion comprising a support and at least one iron-containing compound selected from the group consisting of an iron salt, an iron oxide, and an iron hydroxide supported on the support.

According to a second aspect of the present invention, there is provided a method of preparing a smart film, the method comprising: dispersing a dispersion, a pore-forming agent and a membrane matrix material in a dispersing agent to obtain a membrane casting solution, and carrying out membrane formation on the membrane casting solution, wherein the dispersion contains a carrier and at least one iron-containing compound loaded on the carrier, and the iron-containing compound is selected from iron salt, iron oxide and iron hydroxide.

According to a third aspect of the invention there is provided a smart film produced by the method of the second aspect of the invention.

According to a fourth aspect of the present invention there is provided a membrane module comprising a membrane and a support structure for supporting the membrane, wherein the membrane is a smart membrane according to the first or third aspects of the present invention.

According to a fifth aspect of the present invention, there is provided a membrane-bioreactor, wherein the membrane in the membrane-bioreactor is the smart membrane of the first or third aspect of the present invention, or the membrane module in the membrane-bioreactor is the membrane module of the fourth aspect of the present invention.

According to a sixth aspect of the present invention there is provided the use of the above-described intelligent membrane, membrane module or membrane-bioreactor in water treatment.

According to a seventh aspect of the present invention, there is provided a method of retaining microorganisms in water, the method comprising passing water containing microorganisms through a membrane or membrane module to retain the microorganisms in the water, wherein the membrane is the smart membrane of the first or third aspect of the present invention and the membrane module is the membrane module of the fourth aspect of the present invention.

According to an eighth aspect of the present invention, there is provided a wastewater treatment method, comprising subjecting wastewater to biodegradation in a membrane-bioreactor, and allowing water in the bioreactor to pass through a membrane module under the action of pressure difference between two sides of the membrane to obtain effluent, wherein the membrane-bioreactor is the membrane-bioreactor according to the fifth aspect of the present invention.

Compared with the existing antimicrobial film, the intelligent film has the following advantages:

(1) the intelligent membrane can sense the condition and the area of the membrane polluted by microorganisms, treat the polluted area in a targeted manner, and automatically stop the function after the pollution is relieved;

(2) the intelligent membrane does not kill or inhibit the activity and the quantity of microorganisms in adjacent areas (such as in a biochemical reactor), and has small influence on biochemical reaction;

(3) the intelligent membrane has wide application range and can be applied to most of water treatment environments.

The intelligent membrane can be prepared by adopting a conventional membrane preparation process, and the adopted raw materials are conventional commercially available raw materials, so that the large-scale production is favorably realized.

The intelligent membrane according to the present invention can sense the condition and area of the membrane contaminated by microorganisms, treat the contaminated area with pertinence, and the reason that the function can be automatically stopped after the contamination is relieved may be: the antibacterial performance of iron ions can be changed under the aerobic and anaerobic environments, wherein, Fe²⁺Has broad-spectrum bactericidal and bacteriostatic ability, and Fe³⁺Does not have this function; biochemical processes using membranes are mostly described inWorking under aerobic condition, in the presence of oxygen, the iron carried by the carrier in the film is Fe³⁺The membrane has no sterilization/bacteriostasis function; when the membrane is polluted by microorganisms, the growth and reproduction of the microorganisms and the generated extracellular polymeric substances can prevent oxygen from reaching the surface of the membrane or in pores of the membrane to form a local anaerobic zone; under anaerobic environment, Fe³⁺Converting the electrons into Fe after the electron acceptor becomes the reaction of oxidizing organic matters in water by microorganisms and receiving the electrons²⁺The sterilization/bacteriostasis function is locally started around the carrier enriched with iron, so that the microbial pollution is relieved; alternatively, the killed bacterial cells may provide a carbon source for the process and thus an electron donor until the microbial fouling layer formed is destroyed to expose the iron carried on the membrane to oxygen, which will replace the Fe³⁺Becomes an electron acceptor to regenerate Fe³⁺The form of (2) is stable, and the sterilization/bacteriostasis function of the polluted area on the membrane is automatically closed.

Also, since the change of the valence state of iron by microorganisms occurs both in the ionic state of iron and in the solid form of iron (e.g., iron oxide and iron hydroxide), the smart membrane according to the present invention can be applied to most water treatment environments.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention.

FIG. 1 shows the transmembrane pressure difference as a function of time during the course of the experiment in Experimental example 1 and Experimental comparative examples 1-2, wherein TMP is the transmembrane pressure difference (MPa) on the ordinate and time (day) is the abscissa.

Detailed Description

The following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

According to a first aspect of the present invention, there is provided a smart film comprising a film matrix, and a dispersion dispersed in the film matrix, the dispersion comprising a support and an iron-containing compound supported on the support.

According to the intelligent film of the present invention, the iron in the iron-containing compound may be ferrous iron, ferric iron, or a mixture of ferrous iron and ferric iron. Typically, the iron in the iron-containing compound is ferric iron.

The iron-containing compound may be various compounds capable of providing iron element to the smart film, for example, the iron-containing compound may be one or more selected from iron salts, iron oxides, and iron hydroxides. The iron salt refers to a salt in which at least part of cations are iron ions, and the iron ions can be ferric ions or ferrous ions, and are preferably ferric ions.

Specifically, the iron-containing compound may be one or more selected from an oxysalt having an iron ion as a cation, an iron oxide, and an iron hydroxide. More specifically, the iron-containing compound is one or more selected from the group consisting of an inorganic oxysalt having an iron ion as a cation, an organic acid salt having an iron ion as a cation, a halide having an iron ion as a cation, an iron oxide, and an iron hydroxide.

Preferred examples of the iron-containing compound may include, but are not limited to, ferric chloride, ferric nitrate, ferric sulfate, ferric oxide, and ferric hydroxide. More preferably, the iron-containing compound is one or more of ferric chloride, ferric nitrate and ferric sulfate.

The iron-containing compound is used for endowing the intelligent film with antibacterial performance, and the content of the iron-containing compound is based on that enough antibacterial performance can be endowed to the intelligent film. In general, the content of iron-containing compounds, calculated as iron trioxide, may be from 0.5 to 45% by weight, preferably from 1 to 40% by weight, more preferably from 2 to 30% by weight, based on the total amount of the dispersion. More preferably, the iron-containing compound is present in an amount of 5 to 25% by weight, based on the total amount of the dispersion, so that more stable antibacterial properties can be obtained.

The carrier is used for immobilizing iron-containing compounds, avoids the loss of the iron-containing compounds during use, and enables the iron-containing compounds to be uniformly dispersed in a membrane matrix. The carrier may be a common porous material, and may be one or two or more of a porous inorganic oxide, clay, and molecular sieve, for example.

The porous inorganic oxide may be one or more of alumina, silica, magnesia and zirconia.

The clay may be one or more of kaolin, halloysite, montmorillonite, diatomaceous earth, halloysite, saponite, rectorite, sepiolite, attapulgite, hydrotalcite and bentonite.

The molecular sieve can be one or more than two of a microporous silicon-aluminum molecular sieve, a microporous phosphorus-aluminum molecular sieve and a mesoporous silicon-aluminum molecular sieve, such as one or more than two of a Y-type molecular sieve, an X-type molecular sieve, an A-type molecular sieve, an L-type molecular sieve, a Beta-type molecular sieve, an FER-type molecular sieve, an MOR-type molecular sieve, a ZSM-type molecular sieve, an MCM-type molecular sieve, an SAPO-type molecular sieve, an MCM-type molecular sieve and an SBA-type molecular sieve. Specific examples of the molecular sieve may include, but are not limited to, Y-type molecular sieves, X-type molecular sieves (e.g., 13X molecular sieves, 10X molecular sieves), A-type molecular sieves (e.g., 3A molecular sieves, 4A molecular sieves, 5A molecular sieves), L-type molecular sieves, Beta-type molecular sieves, FER-type molecular sieves, MOR-type molecular sieves, ZSM-5-type molecular sieves, ZSM-22-type molecular sieves, ZSM-11-type molecular sieves, ZSM-23-type molecular sieves, ZSM-35-type molecular sieves, MCM-22-type molecular sieves, MCM-49-type molecular sieves, MCM-36-type molecular sieves, MCM-56-type molecular sieves, SAPO-34-type molecular sieves, SAPO-11-type molecular sieves, SAPO-5-type molecular sieves, SAPO-18-type molecular sieves, APO-5-type molecular sieves, APO-11-type molecular sieves, MeAPO-11-type molecular sieves, MCM-41-type molecular sieves, and the like molecular sieves, One or more than two of MCM-48 type molecular sieve, MCM-50 type molecular sieve, SBA-15 type molecular sieve, SBA-16 type molecular sieve, MSU-1 type molecular sieve and MSU-2 type molecular sieve.

Preferably, the support is a molecular sieve.

The dispersion is used to introduce the iron-containing compound into the membrane matrix and to enable the iron-containing compound to be uniformly dispersed in the membrane matrix. The dispersion is present in an amount sufficient to introduce a sufficient amount of the iron-containing compound into the membrane matrix. Generally, the dispersion may be contained in an amount of 5 to 20 parts by weight, preferably 8 to 18 parts by weight, and more preferably 10 to 15 parts by weight, relative to 100 parts by weight of the film base. The content of the dispersion in the intelligent membrane can be measured by a thermal weight loss method, and can also be determined by the feeding amount (namely, the mass percentage of the dispersion in the raw materials forming the membrane matrix). When the content of the dispersion is measured by adopting a thermal weight loss method, the test conditions are as follows: measuring in air atmosphere, wherein the test initial temperature is 25 ℃, and the heating rate is 10 ℃/min; the samples were dried at a temperature of 150 ℃ and 1 atm under argon atmosphere for 3 hours before the test, and the mass retention at 600 ℃ was taken as the content of the dispersion in the smart film. In the disclosed embodiment of the invention, the content of the dispersion in the smart film is determined by the amount of the feed.

The particle size of the dispersion is not greater than the thickness of the smart film and can be selected based on the thickness of the smart film. Generally, the particle size of the dispersion is in the range of 0.5 to 5 μm, preferably in the range of 0.5 to 2 μm. In the present invention, "in the range of X to X" includes both end values.

According to the smart film of the present invention, the film substrate is typically a polymer film. The polymer in the polymer film may be a common polymer film material, and specific examples thereof may include, but are not limited to, one or more of fluorine-containing polyolefin, polysulfone (including polyethersulfone), polyetherketone, polyamide, polyimide, and polyester. The fluorinated polyolefin is preferably polyvinylidene fluoride. Preferably, the polymer in the polymer membrane is one or a combination of more than two of fluorine-containing polyolefin and polysulfone.

The smart membrane according to the present invention may be a membrane having various conventional forms, for example, a flat membrane or a hollow fiber membrane.

In one embodiment, the smart membrane according to the present invention is a flat sheet membrane. In this embodiment, the smart film may be a self-supporting film. From the viewpoint of further improving the strength of the membrane, the intelligent membrane further comprises a support, and the membrane matrix is attached to at least one surface of the support. The support may be of conventional choice. In particular, the support may be a nonwoven or a fibrous fabric, preferably a nonwoven. In this embodiment, the thickness of the film substrate may be selected according to the particular application of the smart film. Generally, the thickness of the smart film may be 50 to 150. mu.m, preferably 80 to 120. mu.m.

In another embodiment, the smart membrane is a hollow fiber membrane. The dimensions of the hollow fiber membranes may be selected according to the particular application. As an example, the outer diameter of the hollow fiber membrane may be 0.5 to 5mm, preferably 0.5 to 3mm, more preferably 0.5 to 1.5mm when used for water treatment; the wall thickness may be 50-500. mu.m, preferably 80-300. mu.m, more preferably 100-200. mu.m.

According to the smart film of the present invention, the porosity may be 65-85%, preferably 70-83%. The porosity is measured by adopting a weighing method, and the specific operation method comprises the following steps: at the temperature of 25 ℃, placing the wet film which is saturated by wetting in a vacuum oven with the vacuum degree of 0.1MPa, drying at the temperature of 60 ℃ to constant weight to obtain a dry film, weighing the weight change of the film before and after drying, and calculating the pore volume V of the film according to the weight change_Hole(s)Determining the skeleton volume V of the film from the density and dry film weight of the film material_FrameworkThe porosity of the membrane was calculated from the following formula:

porosity [ V ]_Hole(s)/(V_Hole(s)+V_Framework)]×100％。

According to the intelligent membrane of the invention, the pure water flux is generally 80-300L/(m)²H), preferably 100-²H), more preferably 120-²H). The testing method of pure water flux is providedThe body is as follows: making the film into a film assembly: the flat membrane was placed in an ultrafiltration cup (available from Millipore, 30cm effective membrane area)²) The product is directly used after middle sealing; and (3) putting 10 hollow fiber membranes into an organic glass tube which is 30cm long and 8cm in inner diameter and provided with a side water outlet, sealing two ends with epoxy resin to prepare a component, and accurately measuring and calculating the effective membrane area A according to the distance between epoxy layers and the inner diameter of membrane wires. Prepressing the membrane component at room temperature (25 ℃) and 0.15MPa (gauge pressure) for 30 minutes, introducing pure water, keeping the testing pressure at 0.1MPa (gauge pressure), and measuring the volume V of the pure water permeating within a certain time t. The amount of water permeated per unit area of the membrane per unit time, i.e., the pure water flux J, was calculated from the following formula:

J＝V/(A·t)。

The dispersion contains a carrier and an iron-containing compound supported on the carrier. The kind of the iron-containing compound and the carrier have been described in detail above and will not be described herein again.

According to the preparation method of the present invention, the content of the iron-containing compound in the dispersion may be selected according to the amount of the iron-containing compound expected to be introduced in the smart film. In general, the iron-containing compound may be present in an amount of 0.5 to 45 wt.%, preferably 1 to 40 wt.%, more preferably 2 to 30 wt.%, based on the total amount of the dispersion, the iron-containing compound being calculated as iron oxide. More preferably, the iron-containing compound is present in an amount of 5 to 25% by weight, based on the total amount of the dispersion, so that more stable antibacterial properties can be obtained. The content of iron-containing compounds in the dispersion is determined by X-ray fluorescence spectroscopy (XRF), and the content of iron-containing compounds in the dispersion can be determined from the charged amount when the dispersion is prepared by a saturation impregnation method.

According to the production method of the present invention, the particle diameter of the dispersion may be selected according to the intended film thickness so that the particle diameter of the dispersion is not larger than the intended film thickness. In particular, the particle size of the dispersion may be in the range of 0.5 to 5 μm, preferably in the range of 0.5 to 2 μm.

According to the preparation method of the present invention, the amount of the dispersion to be used may be selected depending on the content of the iron-containing compound in the dispersion and the amount of the iron-containing compound to be introduced into the smart film. Generally, the dispersion may be present in an amount of 5 to 20 parts by weight, preferably 8 to 18 parts by weight, and more preferably 10 to 15 parts by weight, relative to 100 parts by weight of the film substrate material.

According to the production method of the present invention, the dispersion may be obtained by supporting an iron-containing compound on a carrier. The iron-containing compound may be supported on the carrier by a conventional method.

As an example, the dispersion may be obtained by loading an iron-containing compound on a carrier by impregnation. Specifically, the carrier may be impregnated with a dispersion in which an iron-containing compound is dispersed. The impregnation may be carried out by saturation or by excess impregnation.

In this instance, the dispersion medium of the dispersion liquid may be a common medium capable of dissolving the iron-containing compound or forming a stable dispersion, and specific examples thereof may include, but are not limited to, alcohol and/or water, preferably water. The amount of iron-containing compound in the dispersion and the number of impregnations may be selected according to the amount of iron-containing compound expected to be introduced on the carrier, so as to be able to introduce a sufficient amount of iron-containing compound on the carrier. The impregnation may be carried out at ambient temperature, such as at a temperature of 10-45 ℃. The duration of the impregnation can be chosen conventionally, so as to be able to achieve an equilibrium of adsorption.

In this case, the solid phase obtained by impregnation may be dried under conventional conditions so as to remove volatile components from the support. Generally, the drying may be carried out at a temperature of from 60 to 180 ℃, preferably at a temperature of from 80 to 150 ℃, more preferably at a temperature of 100 ℃ and 130 ℃. The drying may be performed under normal pressure (i.e., 1 atm), or under reduced pressure. The duration of the drying may be selected according to the temperature and pressure of the drying to maximize the removal of volatile materials from the support. In general, the duration of the drying may be 4 to 24 hours, preferably 6 to 20 hours, more preferably 10 to 18 hours.

The pore-forming agent can be selected conventionally in the field of membrane preparation, and can be one or more than two of polyethylene glycol, cellulose ether, polyurethane and polyvinylpyrrolidone. Specific examples of the cellulose ether may include, but are not limited to, methyl cellulose, hydroxyethyl methyl cellulose, carboxymethyl cellulose, ethyl cellulose, benzyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, cyanoethyl cellulose, benzyl cyanoethyl cellulose, carboxymethyl hydroxyethyl cellulose, and phenyl cellulose. Preferably, the pore-forming agent is polyethylene glycol and/or polyvinylpyrrolidone, such as one or a combination of two or more of polyvinylpyrrolidone, polyethylene glycol 200, polyethylene glycol 300, polyethylene glycol 400, polyethylene glycol 600 and polyethylene glycol 1000.

The amount of the pore-forming agent can be selected conventionally, so that the porosity of the finally prepared membrane can meet the requirement. Generally, the porogen may be used in an amount of 5 to 45 parts by weight, preferably 10 to 42 parts by weight, relative to 100 parts by weight of the membrane matrix material. More preferably, the porogen is used in an amount of 15-40 parts by weight, relative to 100 parts by weight of the membrane matrix material, and the porosity of the membrane thus prepared may be in the range of 65-85%, preferably 70-83%.

The dispersing agent is used for uniformly mixing the dispersion and the pore-forming agent with a membrane matrix material to form a membrane casting solution which can be used for membrane formation. The dispersant may be various liquid substances capable of achieving the above-described functions. Specifically, the dispersant may be one or more of N, N-dimethylamide, N-dimethylacetamide, and N-methylpyrrolidone. The amount of the dispersant may be 900 parts by weight, preferably 850 parts by weight, more preferably 800 parts by weight, and still more preferably 750 parts by weight, per 100 parts by weight of the film substrate material.

The dispersion, porogen, and membrane matrix material may be dispersed in a dispersant using conventional methods to form a membrane casting solution that can be used for membrane formation. In one embodiment, the pore-forming agent may be dispersed in a dispersing agent, the dispersion may be added to the formed dispersion, and after mixing uniformly, the film matrix material may be added to obtain the casting solution. From the viewpoint of further improving the uniformity of dispersion and the dispersion efficiency, it is preferable to disperse the dispersion in the dispersion liquid under the conditions accompanied by shaking. The oscillation may be, for example, an ultrasonic oscillation. The frequency of the ultrasonic oscillation may be 25k to 130kHz, preferably 30 to 100kHz, more preferably 40 to 60 kHz. The duration of the shaking may be 10 minutes to 2 hours, preferably 0.5 to 1 hour. The film matrix material is preferably mixed with the dispersion at a temperature of 70-90 ℃.

According to the production method of the present invention, the casting solution is generally subjected to defoaming treatment to remove bubbles in the casting solution, from the viewpoint of further improving the quality of the produced film. For example, the casting solution may be placed in a vacuum environment to remove air bubbles from the casting solution.

According to the preparation method of the present invention, the casting solution can be formed into a film by a conventional method. For example, the film formation can be performed by a coating method or a solution spinning method.

In one embodiment, the film is formed by a coating method. The specific operations may include: and coating the casting solution on at least one surface of the support, and solidifying the coated casting solution to form a film attached to the surface of the support. The support and its kind are already described in the smart film according to the first aspect of the present invention and will not be described in detail here.

The casting solution may be applied to the surface of the support by conventional methods, such as: the casting solution may be applied to the surface of the support by a doctor blade method or an extrusion coating method. Specific coating processes are well known to those skilled in the art and will not be described in detail herein.

The coating liquid applied on the surface of the support may be solidified under conventional conditions to form a film. For example: the support coated with the casting solution may be cooled with water at ambient temperature (e.g., 10-45 deg.C) to solidify the casting solution and form a film. After the membrane is formed, the support may be removed using conventional methods to provide a self-supporting membrane. It is preferable not to remove the support but to allow the formed film to adhere to the surface of the support, thereby further improving the strength of the prepared film.

In this embodiment, the kind of the support may be selected depending on whether or not the support is finally retained. When the support is not removed, the support may be a nonwoven fabric or a fiber fabric.

In this embodiment, the amount of casting solution may be selected according to the desired thickness of the membrane. Generally, the casting solution is used in an amount such that the thickness of the formed film is 50 to 150. mu.m, preferably 80 to 120. mu.m.

The membrane prepared using this embodiment is a flat sheet membrane.

In another embodiment, the film formation is performed using a solution spinning process. The casting solution adopted by the preparation method has better solution spinning performance, and the hollow fiber membrane can be prepared under the conventional solution spinning condition. Specifically, the membrane casting solution can be used as a spinning solution to be spun together with the core solution, and the spun hollow fiber membrane solution enters the solidification solution to be solidified after passing through a section of air gap, so as to obtain the hollow fiber membrane.

The bore fluid and the coagulating liquid may be conventional choices in the field of solution spinning. As one example, the bore fluid and the coagulating fluid may each be water.

The flow rates of the spinning dope and the core dope may be selected according to the wall thickness and the inner diameter of the hollow fiber membrane to be expected. Generally, the flow rate of the spinning solution may be 1.5 to 8mL/min, preferably 1.8 to 5mL/min, more preferably 2 to 3 mL/min; the flow rate of the bore fluid may be 0.5-8mL/min, preferably 0.8-5mL/min, more preferably 1-2 mL/min. The pressure in the vessel containing the spinning solution may be generally 0.1 to 0.3MPa (gauge pressure), preferably 0.15 to 0.25MPa (gauge pressure). The temperatures of the spinning solution and the core solution may each be from 15 to 30 ℃. The temperatures of the spinning solution and the core solution may be the same or different, and are preferably the same.

The fiber yarn spun by the spinning head of the spinning machine passes through a section of air gap (namely, the distance from the spinning head of the spinning machine to the coagulating liquid), and then enters the coagulating liquid to be coagulated to form the hollow fiber membrane. The length of the air gap may be conventionally selected. In general, the air gap may be 10-30cm, preferably 15-25cm, more preferably 20-25 cm.

The solidified hollow fiber membrane can be collected by a winding wheel, and the rotation condition of the winding wheel is usually controlled to have no traction ratio.

The remaining conditions for solution spinning may be conventional in the art. Generally, the solution spinning conditions are such that the outer diameter of the hollow fiber membrane produced is 0.5 to 2mm, preferably 0.5 to 3mm, more preferably 0.5 to 1.5 mm; the wall thickness is 50-500. mu.m, preferably 80-300. mu.m, more preferably 100-200. mu.m. Methods for selecting specific conditions for solution spinning based on the desired outer diameter and wall thickness are well known to those skilled in the art and will not be described in detail herein.

According to the production method of the present invention, the produced film can be treated by a conventional method so that it can be stored for a long period of time. For example, the production method according to the present invention preferably further comprises immersing the formed film in a mixed solution of glycerin and water for 24 to 48 hours, and then drying the film at ambient temperature (generally 5 to 45 ℃) to a constant weight, thereby obtaining a film that can be stored for a long period of time. The content of glycerin in the mixed solution is preferably 30 to 60 vol%.

According to a fourth aspect of the present invention there is provided a membrane module comprising a membrane and a support structure for supporting the membrane, wherein the membrane is as defined in the first or third aspects of the present invention.

The support structure is used to assemble the membranes into a unit, which may be selected according to the particular type of membrane. For example, when the membrane is a flat membrane, the support structure may be a support structure capable of forming the membrane into one or a combination of two or more of a plate-and-frame membrane module, a wound membrane module, and a mat-type membrane module; when the membrane is a hollow fiber membrane, the support structure may be one that is capable of forming the membrane into a tubular membrane module. Methods of selecting a support structure based on the desired membrane module type are well known to those skilled in the art, and are not described in detail herein, to the extent they are not limiting.

The membranes according to the first and third aspects and the membrane module according to the fourth aspect of the present invention have good antimicrobial properties, and can sense the area of the membrane contaminated by microorganisms, treat the contaminated area in a targeted manner, and simultaneously do not inhibit the activity and the number of microorganisms in the area adjacent to the membrane, and are particularly suitable for membrane-biological processes.

Thus, according to a fifth aspect of the present invention, there is provided a membrane-bioreactor, wherein the membrane in the membrane-bioreactor is the membrane according to the first or third aspect of the present invention, or the membrane module in the membrane-bioreactor is the membrane module according to the fourth aspect of the present invention.

The membrane-bioreactor comprises a membrane separation unit and a biological treatment unit, wherein the membrane separation unit is used for filtering fluid treated by the biological treatment unit so as to retain microorganisms and suspended matters in the fluid and obtain purified fluid. The membrane-bioreactor has a wide range of uses in water treatment.

The membrane-bioreactor according to the present invention is configured to improve the antimicrobial property of the membrane used therein by using the membrane or membrane module provided in the present invention, to extend the life span of the membrane, and thus to extend the stable operation time of the membrane-bioreactor, and is not limited to the configuration and operation manner of the membrane-bioreactor. The construction and operation can be made with reference to existing membrane-bioreactor configurations.

According to a sixth aspect of the present invention there is provided the use of a smart membrane according to the first or third aspects of the present invention, a membrane module according to the fourth aspect of the present invention, or a membrane-bioreactor according to the fifth aspect of the present invention in water treatment.

The intelligent membranes, membrane modules or membrane-bioreactors of the present invention may be incorporated into existing water treatment processes, particularly biochemical treatment processes of water.

The membrane and the membrane component can effectively intercept microorganisms and suspended matters in water, have good antimicrobial performance and can maintain the pressure difference between two sides of the membrane for a longer time, thereby effectively prolonging the service life of the membrane and the membrane component.

When the method of the present invention is used for entrapping microorganisms in water, it may be carried out under conventional conditions as long as the membrane or membrane module of the present invention is used. Generally, the initial pressure differential across the membrane (i.e., the transmembrane pressure differential) may be from 0 to 0.05MPa, preferably from 0.001 to 0.01 MPa.

According to an eighth aspect of the present invention, there is provided a wastewater treatment method, comprising subjecting wastewater to biodegradation in a membrane-bioreactor, and allowing water in the bioreactor to pass through the membrane under the action of a pressure difference between two sides of the membrane to obtain effluent, wherein the membrane-bioreactor is the membrane-bioreactor according to the fifth aspect of the present invention.

According to the sewage treatment method, sewage is treated in the membrane-bioreactor provided by the invention, and the intelligent membrane is adopted in the membrane-bioreactor, so that the area polluted by microorganisms on the membrane can be sensed, the polluted area can be treated in a targeted manner, and the service life of the membrane is prolonged; and the antimicrobial components in the membrane are immobilized on the carrier and are hardly lost from the membrane, so that the number and activity of microorganisms in the bioreactor are not or not substantially affected, thereby more effectively treating the sewage.

The method for treating wastewater according to the present invention is not particularly limited with respect to specific operating conditions, and may be carried out under conventional conditions. For example, the concentration of the activated sludge can be 2000-8000mg/L, preferably 3000-6000mg/L, preferably 3500-5000 mg/L; the water flux can be 5-40L/(m)²H), preferably 10 to 30L/(m)²·h)。

The present invention will be described in detail with reference to examples, but the scope of the present invention is not limited thereto.

In the following examples and comparative examples, the content of the iron-containing compound in the dispersion was measured by X-ray fluorescence spectrometry, and the content of the iron-containing compound in the film prepared was determined from the charged amount.

In the following examples and comparative examples, the porosity of the prepared membrane was measured by a weighing method, which was specifically performed by: at the temperature of 25 ℃, placing the wet film which is saturated by wetting in a vacuum oven with the vacuum degree of 0.1MPa, drying at the temperature of 60 ℃ to constant weight to obtain a dry film, weighing the weight change of the film before and after drying, and calculating the pore volume V of the film according to the weight change_Hole(s)Determining the skeleton volume V of the film from the density and dry film weight of the film material_FrameworkThe porosity of the membrane was calculated from the following formula:

porosity [ V ]_Hole(s)/(V_Hole(s)+V_Framework)]×100％。

In the following examples and comparative examples, the water flux of the prepared membranes was specifically measured by: making the film into a film assembly: the flat membrane was placed in an ultrafiltration cup (available from Millipore, 30cm effective membrane area)²) The product is directly used after middle sealing; and (3) putting 10 hollow fiber membranes into an organic glass tube which is 30cm long and 8cm in inner diameter and provided with a side water outlet, sealing two ends with epoxy resin to prepare a component, and accurately measuring and calculating the effective membrane area A according to the distance between epoxy layers and the inner diameter of membrane wires. Prepressing the membrane component at room temperature (25 deg.C) and 0.15MPa (gauge pressure) for 30 min, introducing pure water to maintain the test pressure at 0.1MPa (gauge pressure), and measuring the volume of pure water permeating within a certain time tAnd V. The amount of water permeated per unit area of the membrane per unit time, i.e., the pure water flux J, was calculated from the following formula:

J＝V/(A·t)。

examples 1-6 are presented to illustrate the smart films of the present invention and methods of making the same.

Example 1

(1) A molecular sieve (Y type molecular sieve available from Zhongpetrochemical ChangLing catalyst works and having a particle size of 0.5 to 2 μm) as a starting material was saturated and impregnated with 120mL of a 0.5mol/L aqueous ferric nitrate solution at room temperature (25 ℃) for 6 hours, and the impregnated mixture was dried at 120 ℃ under 1 atm for 12 hours to obtain a dispersion. Wherein the content of ferric nitrate is 19% by weight, calculated as ferric oxide, based on the total amount of the dispersion.

(2) PEG 600 (available from national pharmaceutical group chemical Co., Ltd.) was dissolved in N, N-dimethylacetamide (DMAc), and then the dispersion prepared in step (1) was added and sonicated (sonication frequency 40kHz) at room temperature (25 ℃) for 0.5 hour. And then, adding polyvinylidene fluoride (PVDF, purchased from Shanghai Sanai Rich New materials Co., Ltd.) powder, and stirring at the temperature of 90 ℃ until the PVDF powder is completely dissolved to obtain a casting solution. Subsequently, the casting solution was placed in a vacuum (degree of vacuum: 0.1MPa) drying oven, and allowed to stand at room temperature (25 ℃ C.) under vacuum for 90 minutes to defoam. Wherein, the composition of the casting solution is as follows: 15 wt% PVDF, 5 wt% PEG 600; DMAc was 79 wt%; the dispersion was 10% by weight of PVDF.

(3) And (3) transferring the casting solution prepared in the step (2) to a feed liquid tank of a hollow fiber spinning machine, sealing, and standing for 60 minutes at the temperature of 30 ℃. Subsequently, nitrogen gas was introduced into the feed tank to pressurize the feed tank, and the pressure was maintained at 0.2 MPa. And opening a metering pump, controlling the flow rate of the spinning solution (namely, the membrane casting solution) to be 2.4mL/min, controlling the flow rate of the core solution (deionized water at the temperature of 30 ℃) to be 1.1mL/min, exposing the spun hollow fiber membrane solution through an air gap of 20cm, then, allowing the hollow fiber membrane solution to enter a water coagulation bath at the temperature of 30 ℃, coagulating into a hollow fiber membrane, and collecting the hollow fiber membrane by a winding wheel, wherein the non-traction ratio is controlled.

(4) Leaching the hollow fiber membrane prepared in the step (3), and then placing the hollow fiber membrane in a glycerol-water solution (the concentration of glycerol is 50 volume percent) at room temperatureAfter soaking for 48 hours at 25 ℃, taking out, and drying to constant weight at room temperature (at 25 ℃) to obtain the intelligent membrane. Wherein the diameter (outer diameter, same below) of the hollow fiber membrane is 1.5mm, the wall thickness is 170 μm, the porosity is 77.6%, and the pure water flux is 157.2L/(m)²·h)。

Comparative example 1

A hollow fiber membrane was prepared in the same manner as in example 1, except that the step (1) was not performed, and the dope solution prepared in the step (2) did not contain a dispersion, thereby preparing a hollow fiber membrane. Wherein the hollow fiber membrane has a diameter of 1.5mm, a wall thickness of 170 μm, a porosity of 76.2%, and a pure water flux of 105.4L/(m)²·h)。

Comparative example 2

A hollow fiber membrane was produced in the same manner as in example 1, except that the step (1) was not performed, and the casting solution was prepared in the step (2), the molecular sieve used as the raw material in the step (1) of example 1 was directly used as a dispersion (i.e., the dispersion used was a molecular sieve not loaded with ferric nitrate), thereby producing a hollow fiber membrane. Wherein the hollow fiber membrane has a diameter of 1.5mm, a wall thickness of 170 μm, a porosity of 77.3%, and a pure water flux of 155.4L/(m)²·h)。

Comparative example 3

A hollow fiber membrane was produced in the same manner as in example 1, except that the step (1) was not performed, and in the step (2), iron nitrate in an amount of 2% by weight of PVDF was directly used in place of the dispersion in the step (2) of example 1 for the preparation of the casting solution, thereby producing a hollow fiber membrane. Wherein the hollow fiber membrane has a diameter of 1.5mm, a wall thickness of 170 μm, a porosity of 75.8%, and a pure water flux of 98.4L/(m)²·h)。

Comparative example 4

A hollow fiber membrane was prepared in the same manner as in example 1, except that the step (1) was not performed, and in the step (2), the dispersion in the step (2) of example 1 was directly replaced with multiwalled carbon nanotubes (purchased from institute of sciences, china, organic chemistry, ltd.) in an amount of 2% by weight of PVDF, for preparing a casting solution, thereby preparing a hollow fiber membrane. Wherein the diameter of the hollow fiber membrane is 1.5mm,the wall thickness is 170 μm, the porosity is 76.5%, and the pure water flux is 150.2L/(m)²·h)。

Comparative example 5

A hollow fiber membrane was prepared in the same manner as in example 1, except that, in the step (1), ferric nitrate was replaced with silver nitrate of an equal weight, thereby preparing a hollow fiber membrane. Wherein the hollow fiber membrane has a diameter of 1.5mm, a wall thickness of 170 μm, a porosity of 77.2%, and a pure water flux of 158.4L/(m)²·h)。

Example 2

(1) A molecular sieve (ZSM-5 type molecular sieve available from Nanjing catalyst, Ltd., particle size of 0.5 to 2 μm) was saturated with 120mL of a 0.5mol/L aqueous solution of ferric nitrate at room temperature (25 ℃ C.) for 6 hours, and the impregnated mixture was dried at 120 ℃ under 1 standard atmospheric pressure for 12 hours to obtain a dispersion. Wherein the content of ferric nitrate is 25% by weight, calculated as ferric oxide, based on the total amount of the dispersion.

(2) PEG 600 (available from national pharmaceutical group chemical Co., Ltd.) was dissolved in N, N-dimethylacetamide (DMAc), and then the dispersion prepared in step (1) was added and sonicated (sonication frequency 40kHz) at room temperature (25 ℃) for 0.5 hour. And then, adding polyvinylidene fluoride (PVDF, purchased from Shanghai Sanai Rich New materials Co., Ltd.) powder, and stirring at the temperature of 90 ℃ until the PVDF powder is completely dissolved to obtain a casting solution. Subsequently, the casting solution was placed in a vacuum drying oven (vacuum degree 0.1MPa), and allowed to stand at room temperature (25 ℃) for 90 minutes under vacuum conditions, to thereby defoam. Wherein, the composition of the casting solution is as follows: 13 wt% PVDF, 5 wt% PEG 600; DMAc 81 wt%; the dispersion was 10% by weight of PVDF.

(3) And (3) coating the membrane casting solution on the surface of the non-woven fabric by a scraper to form a membrane layer with the thickness of 100 microns, then placing the membrane-carrying non-woven fabric in deionized water at the temperature of 25 ℃, solidifying for 3 minutes, and taking out to obtain the flat membrane supported by the non-woven fabric.

(4) Washing flat membrane supported by non-woven fabric with deionized water, soaking the membrane in 25 deg.C glycerol-water solution (glycerol concentration is 50 vol%) for 36 hr, taking out, and standing at room temperature(25 ℃) to constant weight, thus obtaining the intelligent membrane according to the invention. Wherein the porosity of the membrane is 80.6%, and the pure water flux is 197L/(m)²·h)。

Example 3

A flat sheet membrane was prepared in the same manner as in example 2, except that, in the step (1), the molecular sieve was replaced with an equal weight of alumina (available from midpetrochemical long-distance corporation), thereby obtaining an intelligent membrane according to the invention, in which the content of ferric nitrate was 24% by weight, based on the total amount of the prepared dispersion, based on ferric oxide. Wherein the porosity of the membrane is 79.3%, and the pure water flux is 190.8L/(m)²·h)。

Example 4

A flat sheet membrane was prepared in the same manner as in example 2, except that in step (1), the concentration of the iron nitrate solution was 1mol/L and the amount of the iron nitrate solution was kept constant, and the content of iron nitrate was 30% by weight based on the total amount of the dispersion, based on iron trioxide, to thereby obtain an intelligent membrane according to the invention. Wherein the porosity of the membrane is 81.5%, and the pure water flux is 174.5L/(m)²·h)。

Example 5

(1) A molecular sieve (MCM-41 type molecular sieve available from catalyst works of southern Kai university and having a particle size of 0.5 to 2 μm) was saturated with 100mL of a 0.5mol/L aqueous solution of ferric chloride at room temperature (25 ℃ C.) for 6 hours, and the impregnated mixture was dried at 110 ℃ C. for 16 hours under 1 standard atmospheric pressure to obtain a dispersion. Wherein the content of ferric chloride is 10 wt% calculated by ferric oxide based on the total amount of the dispersion.

(2) Polyvinylpyrrolidone (available from shanghai jinmantai chemical co., ltd.) was dissolved in N-methylpyrrolidone (NMP), and then the dispersion prepared in step (1) was added and sonicated (sonication frequency 40kHz) at room temperature (25 ℃) for 0.5 hours. Then, polysulfone powder (PSF, available from shanghai plastic industries co., ltd.) was added and stirred at a temperature of 80 ℃ until completely dissolved to obtain a casting solution. Subsequently, the casting solution was placed in a vacuum drying oven (vacuum degree 0.1MPa), and allowed to stand at room temperature (25 ℃) for 90 minutes under vacuum conditions, to thereby defoam. Wherein, the composition of the casting solution is as follows: PSF 12 wt%, polyvinylpyrrolidone 2 wt%; NMP 85 wt%; the dispersion was 10% by weight of the PSF.

(3) And (3) transferring the casting solution prepared in the step (2) to a feed liquid tank of a hollow fiber spinning machine, sealing, and standing for 60 minutes at the temperature of 30 ℃. Subsequently, nitrogen gas was introduced into the feed tank to pressurize the feed tank, and the pressure was maintained at 0.2 MPa. And opening a metering pump, controlling the flow rate of the spinning solution (namely, the membrane casting solution) to be 2.2mL/min, controlling the flow rate of the core solution (deionized water at the temperature of 30 ℃) to be 1.5mL/min, exposing the spun hollow fiber membrane solution through an air gap of 25cm, then, allowing the hollow fiber membrane solution to enter a water coagulation bath at the temperature of 30 ℃, coagulating into a hollow fiber membrane, and collecting the hollow fiber membrane by a winding wheel, wherein the non-traction ratio is controlled.

(4) And (3) rinsing the hollow fiber membrane prepared in the step (3), soaking the hollow fiber membrane in a glycerol-water solution (the concentration of glycerol is 30 vol%) for 60 hours, taking out the hollow fiber membrane, and drying the hollow fiber membrane to constant weight at room temperature (25 ℃), thereby obtaining the intelligent membrane. Wherein the hollow fiber membrane has a diameter of 0.5mm, a wall thickness of 120 μm, a porosity of 73.2%, and a pure water flux of 141L/(m)²·h)。

Example 6

(1) A molecular sieve (Beta type molecular sieve, available from catalyst works of kakko university, south china, having a particle size of 0.5 to 2 μm) was saturated and impregnated with 120mL of a 0.1mol/L aqueous solution of iron sulfate (pH 6) at room temperature (25 ℃) for 8 hours, and the impregnated mixture was dried at 120 ℃ under 1 atm for 12 hours to obtain a dispersion. Wherein, based on the total amount of the dispersoid, the content of ferric sulfate is 5 percent by weight based on ferric oxide.

(2) PEG 1000 (purchased from national chemical reagent) was dissolved in N, N-Dimethylformamide (DMF), and then the dispersion prepared in step (1) was added and sonicated (sonication frequency 60kHz) at room temperature (25 ℃) for 1 hour. Subsequently, polyethersulfone powder (PES, available from BASF chemical) was added and stirred at a temperature of 70 ℃ until completely dissolved to give a casting solution. Subsequently, the casting solution was placed in a vacuum drying oven (vacuum degree 0.1MPa), and allowed to stand at room temperature (25 ℃) for 90 minutes under vacuum conditions, to thereby defoam. Wherein, the composition of the casting solution is as follows: 14% by weight of PES and 5% by weight of PEG 1000; DMF accounted for 80 wt%; the dispersion was 15% by weight of PES.

(3) And (3) transferring the casting solution prepared in the step (2) to a feed liquid tank of a hollow fiber spinning machine, sealing, and standing for 60 minutes at the temperature of 30 ℃. Subsequently, nitrogen gas was introduced into the feed tank to pressurize the tank, and the pressure was maintained at 0.25 MPa. And opening a metering pump, controlling the flow rate of the spinning solution (namely, the membrane casting solution) to be 3mL/min, controlling the pump rotating speed of the core solution (deionized water at the temperature of 30 ℃) to be 1.6mL/min, exposing the spun hollow fiber membrane solution through an air gap of 20cm, then feeding the hollow fiber membrane solution into a water coagulation bath at the temperature of 30 ℃, and collecting the hollow fiber membrane solution after the hollow fiber membrane solution is coagulated into a hollow fiber membrane by a winding wheel, wherein the traction ratio is not controlled.

(4) And (3) rinsing the hollow fiber membrane prepared in the step (3), soaking the hollow fiber membrane in deionized water for 24 hours, soaking the hollow fiber membrane in a glycerol-water solution (the concentration of glycerol is 60 vol%) for 24 hours, taking out the hollow fiber membrane, and drying the hollow fiber membrane to constant weight at room temperature (25 ℃), thereby obtaining the intelligent membrane. Wherein the hollow fiber membrane has a diameter of 1.5mm, a wall thickness of 200 μm, a porosity of 75.7%, and a pure water flux of 126.2L/(m)²·h)。

Experimental examples 1-6 are intended to illustrate the present invention.

Experimental examples 1 to 6

The membranes prepared in examples 1 to 6 were assembled into membrane modules with epoxy resin headers (in which the hollow fiber membranes were made into curtain-type membrane modules and the flat sheet membranes were made into plate-and-frame-type membrane modules). Establishing a set of immersed MBR biochemical reactor (with the size of 0.5 multiplied by 0.25 multiplied by 0.5 meter), immersing the membrane component in the manually configured sewage (controlling COD to be about 300mg/L and NH₃N is about 30mg/L, pH is about 7), the filling membrane accounts for 50 percent of the volume of the pool, and the water flux is controlled to be 15L/(m)²H). The bottom of the reactor is provided with an aeration pipe, and the gas-water ratio is 10: 1. and controlling a water inlet pump of the reactor and a water outlet suction pump of the membrane module to keep the hydraulic retention time at 5 h. The biochemical sludge was taken from a municipal sewage treatment plant, the experiment was started after inoculation and acclimation for 4 weeks in MBR, and the concentration of the activated sludge in the reactor was measured by the gravimetric method of GB 11901-89, and the results are shown in Table 1.

The experiment was carried out continuously at room temperature (25 c) and the vacuum on the effluent side of the membrane module, i.e. the transmembrane pressure difference (TMP) and the activated sludge concentration were monitored over time during the experiment and the results are listed in table 1.

Comparative Experimental examples 1 to 5

Membrane modules were prepared and tested in the same manner as in Experimental examples 1-6, and the results are shown in Table 1.

Comparative example

The MBR biochemical reactor was operated under the same conditions as in examples 1-6, except that no membrane was loaded.

TABLE 1

FIG. 1 shows the change of transmembrane pressure difference with time during the experiment in Experimental example 1 and comparative Experimental examples 1-2. As can be seen from FIG. 1, the intelligent membrane according to the present invention can maintain the transmembrane pressure difference in the working interval for a long time (up to 50 days), and the fluctuation of the transmembrane pressure difference is frequent during the operation, indicating the change of the biological contamination resistance of the membrane material under the local aerobic and anoxic environments on the membrane during the continuous operation. However, in comparative experiment examples 1-2, the membrane can only stably operate for about 20 days under normal working conditions, the pollution tendency is basically linearly changed until the transmembrane pressure difference is remarkably increased, which indicates that the membrane pores are seriously blocked, and the membrane needs to be cleaned and even replaced.

The results in table 1 show that the concentration of activated sludge in the biochemical pond is substantially stable and slightly increased during the experiment compared with the initial period of the experiment by using the intelligent membrane of the invention. The film carrying silver ions with excellent bactericidal performance obviously inhibits the growth of microorganisms in the reactor, and the intelligent film can not generate adverse effects on the quantity and activity of microorganisms in a biochemical pool under the condition of improving the capability of resisting microorganisms by itself.

The preferred embodiments of the present invention have been described in detail, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.

It should be noted that the various technical features described in the above embodiments can be combined in any suitable manner without contradiction, and the invention is not described in any way for the possible combinations in order to avoid unnecessary repetition.

In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.

Claims

1. A sewage treatment method comprises the steps of carrying out biodegradation on sewage in a membrane-bioreactor, and enabling water in the bioreactor to pass through a membrane under the action of pressure difference between two sides of the membrane to obtain effluent, wherein the membrane in the membrane-bioreactor is an intelligent membrane, the intelligent membrane comprises a membrane matrix and a dispersion dispersed in the membrane matrix, the dispersion comprises a carrier and at least one iron-containing compound loaded on the carrier, the iron-containing compound is one or more than two selected from iron salt, iron oxide and iron hydroxide, the porosity of the intelligent membrane is 65-85%, and the water flux of the intelligent membrane is 80-300L/(m & lt/m & gt)²·h)。

2. The process according to claim 1, wherein the iron-containing compound is present in an amount of 0.5 to 45% by weight, based on the total amount of the dispersion, calculated as iron oxide.

3. The process according to claim 2, wherein the content of iron-containing compounds, calculated as iron oxide, is from 1 to 40% by weight, based on the total amount of the dispersion.

4. The process according to claim 3, wherein the content of iron-containing compounds, calculated as iron oxide, is from 2 to 30% by weight, based on the total amount of the dispersion.

5. The process according to claim 4, wherein the content of iron-containing compounds, calculated as iron oxide, is from 5 to 25% by weight, based on the total amount of the dispersion.

6. The method according to any one of claims 1 to 5, wherein the dispersion is contained in an amount of 5 to 20 parts by weight with respect to 100 parts by weight of the film base.

7. The method of claim 6, wherein the dispersion is present in an amount of 8 to 18 parts by weight per 100 parts by weight of the film matrix.

8. The method of claim 7, wherein the dispersion is present in an amount of 10 to 15 parts by weight per 100 parts by weight of the film substrate.

9. The method according to any one of claims 1 to 5, wherein the iron-containing compound is one or more selected from the group consisting of an oxysalt of a cation containing an iron ion, an oxide of iron, and a hydroxide of iron.

10. The method according to claim 9, wherein the iron-containing compound is one or more selected from the group consisting of an inorganic oxoacid salt in which the cation is an iron ion, an organic acid salt in which the cation is an iron ion, a halide in which the cation is an iron ion, an oxide of iron, and a hydroxide of iron.

11. The method of claim 10, wherein the iron-containing compound is one or more of ferric chloride, ferric nitrate, ferric sulfate, ferric oxide, and ferric hydroxide.

12. The method of any of claims 1-5, wherein the particle size of the dispersion is no greater than the thickness of the smart film.

13. The method of claim 12, wherein the particle size of the dispersion is in the range of 0.5-5 μ ι η.

14. The method of claim 13, wherein the particle size of the dispersion is in the range of 0.5-2 μ ι η.

15. The method according to any one of claims 1 to 5, wherein the carrier is one or more selected from porous inorganic oxides, clays and molecular sieves.

16. The method of claim 15, wherein the support is a molecular sieve.

17. The method of any one of claims 1-5, wherein the membrane substrate is a polymer membrane.

18. The method according to claim 17, wherein the polymer in the polymer membrane is one or more selected from the group consisting of fluorine-containing polyolefin, polysulfone, polyetherketone, polyamide, polyimide, and polyester.

19. The method of claim 18, wherein the polymer in the polymer membrane is one or a combination of two or more of polyvinylidene fluoride and polysulfone.

20. The method of any one of claims 1-5, wherein the smart membrane is a hollow fiber membrane.

21. The method of claim 20, wherein the hollow fiber membrane has an outer diameter of 0.5-2mm and a wall thickness of 50-500 μ ι η.

22. The method of claim 21, wherein the hollow fiber membrane has a wall thickness of 80-300 μ ι η.

23. The method as claimed in claim 22, wherein the hollow fiber membrane has an outer diameter of 0.5-1.5mm and a wall thickness of 100-200 μm.

24. The method of any one of claims 1-5, wherein the smart membrane is a flat sheet membrane.

25. The method of claim 24, wherein the smart film further comprises a support, the film matrix being attached to at least one surface of the support.

26. The method of claim 25, wherein the support is a nonwoven or a fiber fabric.

27. The method of claim 24, wherein the film substrate has a thickness of 50-150 μ ι η.

28. The method of claim 27, wherein the membrane substrate has a thickness of 80-120 μ ι η.

29. The method of claim 1, wherein the porosity of the smart membrane is 70-83%.

30. The method as claimed in any one of claims 1 to 5 and 29, wherein the water flux of the smart membrane is 100-²·h)。

31. The method as claimed in claim 30, wherein the water flux of the smart membrane is 120-220L/(m)²·h)。

32. The method of any one of claims 1-5 and 29, wherein the method of making the smart film comprises: dispersing a dispersion, a pore-forming agent and a membrane matrix material in a dispersing agent to obtain a membrane casting solution, and forming a membrane from the membrane casting solution, wherein the dispersion contains a carrier and at least one iron-containing compound loaded on the carrier, and the iron-containing compound is one or more than two selected from iron salt, iron oxide and iron hydroxide.

33. The method according to claim 32, further comprising a step of providing the dispersion in which the carrier is impregnated with a dispersion in which an iron-containing compound is dispersed, the carrier loaded with the dispersion is soaked in water for 4 to 8 hours, solid-liquid separation is performed, and the solid phase obtained by the separation is dried.

34. The method of claim 32, wherein the porogen is present in an amount of 5-45 parts by weight relative to 100 parts by weight of membrane matrix material.

35. The method of claim 34, wherein the porogen is present in an amount of 10-42 parts by weight relative to 100 parts by weight of membrane matrix material.

36. The method of claim 35, wherein the porogen is present in an amount of 15-40 parts by weight relative to 100 parts by weight of membrane matrix material.

37. The method of claim 32, wherein the porogen is one or more selected from polyethylene glycol, cellulose ether, polyurethane, polyvinylpyrrolidone.

38. The method of claim 32, wherein the film matrix material is a polymer.

39. The method of claim 38, wherein the membrane base material is one or more selected from the group consisting of fluorine-containing polyolefin, polysulfone, polyetherketone, polyamide, polyimide, and polyester.

40. The method of claim 39, wherein the membrane matrix material is one or a combination of two or more of polyvinylidene fluoride and polysulfone.

41. The method of claim 32, wherein the film forming method is a coating method or a solution spinning method.

42. The method of claim 41, wherein the method of forming a film comprises: and coating the casting solution on at least one surface of the support, and solidifying the coated casting solution to form the membrane.

43. The method of claim 42, wherein the support is a nonwoven or a fibrous fabric.

44. A method according to claim 42, wherein the dope solution is used in an amount such that the formed film has a thickness of 50-150 μm.

45. A method according to claim 44, wherein the dope solution is used in an amount such that the formed film has a thickness of 80-120 μm.

46. The method of claim 41, wherein the method of forming a film comprises: and spinning the membrane casting solution and the core solution together as spinning solution, and allowing the spun hollow fiber membrane solution to pass through a section of air gap and enter solidification solution for solidification to obtain the hollow fiber membrane.

47. The method of claim 46, wherein the bore fluid and the solidifying fluid are each water.

48. The process of claim 46, wherein the flow rate of the spinning dope is 1.5-8mL/min and the flow rate of the core liquid is 0.5-8 mL/min.

49. The process of claim 48, wherein the flow rate of the spinning dope is 1.8-5mL/min and the flow rate of the core liquid is 0.8-5 mL/min.

50. The process of claim 49, wherein the flow rate of the spinning dope is 2-3mL/min and the flow rate of the core liquid is 1-2 mL/min.

51. The method of claim 46, wherein the air gap is 10-30 cm.

52. The method of claim 51, wherein the air gap is 15-25 cm.

53. The method of claim 52, wherein the air gap is 20-25 cm.

54. The method according to claim 46, wherein the spinning dope and the core dope are used in amounts such that the hollow fiber membrane formed has an outer diameter of 0.5 to 2mm and a wall thickness of 50 to 500 μm.

55. The process of claim 54, wherein the spinning dope and the core dope are used in amounts such that the wall thickness of the formed hollow fiber membrane is 80-300 μm.

56. The method according to claim 55, wherein the spinning dope and the core dope are used in amounts such that the outer diameter of the formed hollow fiber membrane is 0.5 to 1.5 mm; the wall thickness is 100-.

57. The method of claim 32, further comprising drying the formed film after soaking the film in a mixture of glycerol and water, wherein the glycerol content of the mixture is 30-60 vol% for 24-84 hours.