Modular sewage purification material and preparation method and application thereof

Abstract

The present application relates to a kind of modular sewage purification material and its preparation method and application, belong to sewage purification material technical field.The present application discloses a kind of modular sewage purification material, comprising: isolation layer module;And switchable function layer module, it is single-layer or multilayer structure, including oil-water separation function module, heavy metal adsorption function module, sterilization function module, micro-nano plastic purification module one or more kinds.The present application also discloses a kind of preparation method of modular sewage purification material;The present application also discloses a kind of modular sewage purification material in sewage treatment.

Description

Technical Field

[0001] This invention belongs to the field of wastewater purification materials technology, and relates to a modular wastewater purification material, its preparation method, and its application. Background Technology

[0002] Water scarcity is a global issue, and with rapid societal development, existing water resources are severely polluted, including by heavy metals, organic chemicals, particulate matter, and biological contamination. These pollutants, entering the human body through drinking water, can harm organs, trigger acute or chronic diseases, and seriously threaten public health and safety. Therefore, it is urgent to find effective strategies to address this critical situation.

[0003] Membrane separation, with its advantages of high efficiency and simple operation, is considered the most advantageous water purification technology. However, some membrane separation materials have limited functions; for example, oil-water separation membranes can only purify oil pollutants in water, and heavy metal adsorption membranes only effectively purify heavy metal pollutants. Nanofiltration and reverse osmosis membranes, due to their nanoscale pore size, can purify a variety of pollutants, but their high transmembrane resistance requires operation under external high pressure, limiting their practical application in water treatment. Wastewater from different sources contains different pollutants. Developing a modular wastewater purification material, allowing for the selection of different purification modules for different pollutants and switching between pollutant purification functions, could significantly improve wastewater purification efficiency and prevent the material's effectiveness from becoming ineffective or excessive due to changes in pollutant types.

[0004] Chinese patent application (publication number: CN106552519A) discloses a method for preparing and applying a superhydrophilic and underwater superoleophobic calcium carbonate hybrid membrane. The method includes the following steps: adding a calcium ion solution to an alginate sol to prepare a calcium alginate gel, followed by stirring to form flocculation and precipitation; then adding a carbonate solution to obtain calcium carbonate-calcium alginate hybrid particles; and finally, filtration and drying to obtain the superhydrophilic and underwater superoleophobic calcium carbonate hybrid membrane. The membrane prepared by this method is mainly used for oil-water separation, and its ability to filter and purify pollutants in water is not mentioned. In fact, most current filter materials can only achieve oil-water separation or purification of other single pollutants. Single filter materials cannot switch functions for different pollutants, leading to cumbersome pollutant treatment steps and complex equipment. Therefore, there is an urgent need to develop a material that can switch functions for different pollutants and can be applied to a simple device to purify water. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned problems in the existing technology by proposing a modular wastewater purification material that can switch functions for different pollutants and can be applied to a simple device to purify water.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A modular wastewater purification material, comprising: an isolation layer module and a switchable functional layer module, wherein the functional layer module is a single-layer or multi-layer structure, including one or more of the following: an oil-water separation functional module, a heavy metal adsorption functional module, a sterilization functional module, and a micro / nanoplastics purification module.

[0008] The modular wastewater treatment material features switchable functional modules that can be selected based on different pollutants in the wastewater, enabling targeted purification. A schematic diagram of the modular wastewater treatment material prepared according to this invention is shown below. Figure 1 As shown. The switchable functional layer module is in contact with the wastewater. This module has a large specific surface area and high porosity, with functional groups present on its surface and inside. Different types of functional layer modules have different functions, allowing for adjustment and compounding to address the types of pollutants in the wastewater, thus avoiding functional overload while meeting the pollutant purification requirements. When the switchable functional layer module has a multi-layer structure, any one of the following functional modules—oil-water separation, heavy metal adsorption, sterilization, and micro / nanoplastics purification—can be connected to the isolation layer module or to the wastewater itself.

[0009] Preferably, the isolation layer module has a dense structure and a negative surface potential; the switchable functional layer module has a porous structure and a positive surface potential, with a specific surface area of ​​220-300 m². 2 / g, with a porosity of 25-50%.

[0010] Preferably, the surface pore size of the isolation layer module is 1-5 nm; the surface pore size of the switchable functional layer module is 40-55 μm.

[0011] Preferably, the total thickness of the modular wastewater purification material is 100-2000 μm.

[0012] Further preferably, the thickness of the isolation layer module is 20-50 μm; the thickness of the switchable functional layer module is 100-1900 μm.

[0013] More preferably, the thickness ratio of the isolation layer module and the switchable functional layer module is 1:(10-30).

[0014] The thickness of wastewater treatment materials affects their permeation flux and purification efficiency. Generally, thicker materials offer better water purification but have lower water flux. Thinner materials have higher water flux but lower purification efficiency. Choosing an appropriate material thickness can balance purification effectiveness with separation efficiency.

[0015] Preferably, the switchable functional layer module is prepared from raw materials including alginate, modifier, and pore-forming agent.

[0016] Further preferably, the mass ratio of the alginate, modifier, and pore-forming agent is 1:(0.1-3):(0.1-3).

[0017] Preferably, the raw materials for the switchable functional layer module may also include one or more of the following: catalyst, promoter, and activator.

[0018] Preferably, the pore-forming agent is waterborne polyurethane.

[0019] In this invention, waterborne polyurethane is used as a pore-forming agent. It does not participate in chemical reactions; its purpose is to create a uniform porous structure in the material, thereby improving water flux and purification efficiency. Insufficient pore-forming agent will result in a dense functional layer and low water flux; excessive pore-forming agent will lead to overly developed pores in the functional layer, compromising the purification effect.

[0020] Preferably, the modifier includes one or more of the following: polycarboxylated amine, chitosan, cellulose, carboxymethyl cellulose, citric acid, sodium citrate, ethylenediaminetetraacetic acid, tetraethylenepentamine, sodium lignosulfonate, polyaniline, penicillamine, polyethyleneimine, polymethyl methacrylate, and sulfobetaine methacrylate.

[0021] When the modifier is a single component, the resulting functional layer module has a single function; when the modifier is a composite component, the resulting functional layer module has multiple functions. When the switchable functional layer module has a single-layer structure, the resulting modular wastewater purification material has a single function; when the switchable functional layer module has a multi-layer structure, the resulting modular wastewater purification material has multiple functions simultaneously. Preferably, the modifier in the oil-water separation functional module includes one or more of sodium citrate, cellulose, and carboxymethyl cellulose.

[0022] Further preferably, the thickness of the oil-water separation functional module is 100-380μm.

[0023] Further preferably, the surface pore size of the oil-water separation functional module is 40-50μm.

[0024] Preferably, the modifier in the heavy metal adsorption module includes one or more of ethylenediaminetetraacetic acid, polyaniline, citric acid, and tetraethylenepentamine.

[0025] Further preferably, the thickness of the heavy metal adsorption functional module is 100-300μm.

[0026] Further preferably, the surface pore size of the heavy metal adsorption module is 42-55 μm.

[0027] Preferably, the modifier in the sterilization module includes one or more of polyethyleneimine, penicillamine, polymethyl methacrylate, and sodium lignosulfonate.

[0028] Further preferably, the thickness of the sterilization module is 100-350μm.

[0029] Further preferably, the surface pore size of the sterilization module is 45-55 μm.

[0030] Preferably, the modifier in the micro / nanoplastics purification module includes one or more of polyamine carbide, chitosan, and sulfobetaine methacrylate. More preferably, the thickness of the micro / nanoplastics purification module is 100-370 μm.

[0031] Further preferably, the surface pore size of the micro-nano plastic purification functional module is 40-50μm.

[0032] Preferably, when the switchable functional layer module includes two of the following: an oil-water separation functional module, a heavy metal adsorption functional module, a sterilization module, and a micro-nano plastic purification module, the thickness is 100-600μm.

[0033] Preferably, when the switchable functional layer module includes three of the following: an oil-water separation functional module, a heavy metal adsorption functional module, a sterilization module, and a micro-nano plastic purification module, the thickness is 100-1000μm.

[0034] Preferably, when the switchable functional layer module includes four of the following: oil-water separation module, heavy metal adsorption module, sterilization module, and micro-nano plastic purification module, the thickness is 100-1400μm.

[0035] This invention also provides a method for preparing a modular wastewater purification material, the method comprising the following steps: dissolving alginate in deionized water to prepare an alginate sol, which is divided into N portions; in the first (N-1) rounds of spraying, taking one portion and adding a modifier and a pore-forming agent to obtain a functional layer module sol, and using spraying to solidify the functional layer module sol on the surface of a crosslinking agent ice block to obtain a crude modular functional layer; covering the surface of the crude functional layer with the Nth portion of alginate sol through the Nth round of spraying, and then immersing it in a crosslinking agent solution to obtain a crude modular wastewater purification material, and then using vacuum freeze-drying to obtain a modular wastewater purification material including an isolation layer module and a switchable functional layer module.

[0036] As a preferred option, N≥2.

[0037] Preferably, in the first to (N-1) rounds of spraying, the number of spraying times is 10-80.

[0038] Preferably, the alginate is one or more of sodium alginate, potassium alginate, and ammonium alginate.

[0039] More preferably, the concentration of the alginate sol is 0.5-5 wt.%.

[0040] Preferably, the crosslinking agent includes one or more of copper sulfate, ferric sulfate, magnesium chloride, copper chloride, and calcium chloride.

[0041] Preferably, the concentration of the crosslinking agent is 0.1-10 wt.%.

[0042] More preferably, the concentration of the crosslinking agent is 0.5-5 wt.%.

[0043] Within the above-mentioned crosslinking agent concentration range, the crosslinking is sufficient and uniform, resulting in a membrane with few defects and high quality.

[0044] Preferably, the temperature of the crosslinking agent solution is 0-5°C.

[0045] Low-temperature crosslinking can prevent defects such as uneven crosslinking and wrinkles caused by excessively rapid crosslinking. In this invention, the obtained solid sol is immersed in a low-temperature crosslinking agent solution. The upper surface of the solid sol is slowly and uniformly crosslinked under the action of metal ions from the crosslinking agent, while the lower surface of the solid sol is simultaneously crosslinked under the action of metal ions released from the melting ice surface of the same type of crosslinking agent. After the ice surface has completely melted, a modular wastewater purification material with uniform crosslinking is obtained.

[0046] Preferably, the spraying mass ratio in the first (N-1) rounds to the Nth round is (3-9):1.

[0047] Preferably, the vacuum freeze-drying temperature is (-60)-(-90)℃ and the drying time is 12-36h.

[0048] This invention also provides an application of modular wastewater purification materials in wastewater treatment.

[0049] Preferably, the modular wastewater purification material is combined with a water purification device.

[0050] Further preferably, the water purification device includes, but is not limited to, water cups, kettles, and buckets, and may also include disposable water purification devices, simple outdoor water purification devices, and emergency water treatment devices.

[0051] The modular wastewater purification material obtained by this invention can be combined with a water purification device to purify target wastewater. The wastewater can include oily wastewater, heavy metal ion wastewater, biological wastewater, and wastewater containing micro-nano particles. Oily wastewater can include liquid paraffin, chloroform, diesel, gasoline, cyclohexane, n-hexane, edible oil, etc.; heavy metal ion wastewater includes wastewater from electroplating plants, leather factories, etc., containing lead ions, copper ions, cobalt ions, cadmium ions, etc.; biological wastewater includes wastewater containing Gram-positive bacteria, Gram-negative bacteria, and pathogenic microorganisms; wastewater containing micro-nano particles includes wastewater containing insoluble natural particles, artificial microplastics, and other micro-nano-scale impurities.

[0052] The modular wastewater purification material prepared by this invention has an oil-water separation efficiency greater than 99.5% when the oil-water separation functional module is combined with the isolation layer module, a heavy metal ion removal efficiency greater than 99.5% when the heavy metal adsorption functional module is combined with the isolation layer module, a micro-nano plastic purification module with an isolation layer module, a micro-nano particle removal efficiency greater than 99.9% when the micro-nano plastic purification module is combined with the isolation layer module, and can effectively kill bacteria in water when the sterilization module is combined with the isolation layer module.

[0053] The present invention can also combine two or more of the oil-water separation module, heavy metal adsorption module, sterilization module, and micro-nano plastic purification module as a switchable functional layer module, while still maintaining a good purification effect.

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] 1. The modular wastewater purification material of this invention, which includes an isolation layer module and a switchable functional layer module, allows for the selection of the optimal functional layer module for different pollutants in wastewater to achieve efficient purification of the target pollutants, avoiding excess or deficiency of functions.

[0056] 2. The modular wastewater purification material of the present invention includes two or more of the following switchable functional layer modules: oil-water separation functional module, heavy metal adsorption functional module, sterilization module, and micro-nano plastic purification module. These modules work together with the isolation layer module to achieve multiple effects in one, and the overall purification performance is excellent.

[0057] 3. The wastewater treatment process of the present invention does not require the application of external pressure; complex wastewater can be purified in one step under the action of gravity.

[0058] 4. The modular wastewater purification material obtained by this invention can be combined with a water purification device to complete the purification of wastewater.

[0059] 5. The preparation method of the present invention is simple, the raw material cost is low, and it can be mass-produced. Attached Figure Description

[0060] Figure 1 This is a schematic diagram of the modular wastewater purification material obtained by the present invention.

[0061] Figure 2 This is a scanning electron microscope image of the cross-section of the modular wastewater purification material prepared in Example 1 of the present invention.

[0062] Figure 3 This is a scanning electron microscope image of the modular wastewater purification material isolation layer module prepared in Embodiment 1 of the present invention.

[0063] Figure 4 This is an electron microscope image of the oil-water separation functional module of the modular wastewater purification material prepared in Embodiment 1 of the present invention.

[0064] Figure 5 This is a schematic diagram of the modular wastewater purification material prepared in Embodiment 9 of the present invention.

[0065] Figure 6 This is a schematic diagram of the modular wastewater purification material prepared in Embodiment 10 of the present invention.

[0066] Figure 7 This is a schematic diagram of the modular wastewater purification material prepared in Embodiment 11 of the present invention.

[0067] In the diagram: A is the isolation layer module, B is the switchable functional layer module, 1 is the sterilization module, 2 is the oil-water separation module, 3 is the heavy metal adsorption module, and 4 is the micro-nano plastic purification module. Detailed Implementation

[0068] The following are specific embodiments of the present invention, which further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0069] Preparation of Class I wastewater: Add 5g of chloroform to 100ml of ultrapure water and stir vigorously with a magnetic force to obtain a chloroform-oil-water mixture. Preparation of Class II wastewater: Prepare 5mg / L solutions of Pb... 2+ Cd 2+ Cu 2+ 40 ml of aqueous solution. For Class III wastewater: Prepare 100 mg / L solutions of polystyrene (PS) and polyvinyl chloride (PVC) nanoparticles respectively. For Class IV wastewater: Prepare solutions with a bacterial density of 10... 7 100 mL of CFU bacterial solution contained Escherichia coli and Staphylococcus aureus at densities of 5 × 10⁻⁶. 6 CFU.

[0070] The modular wastewater purification material prepared below is combined with copper mesh to form a water cup with the functional layer on the outside; then the water cup is placed in the wastewater prepared above. The oil-water separation efficiency R, heavy metal ion removal efficiency AE, micro-nano particle removal efficiency RP, and bacterial killing efficiency BP are calculated according to the following formulas. The specific data are shown in Table 1.

[0071] Formula for calculating oil-water separation efficiency (R, %):

[0072]

[0073] In the formula, C f and C o These represent the oil concentrations in the filtrate and the oil-water mixture, respectively.

[0074] Formula for calculating heavy metal removal efficiency (AE, %):

[0075]

[0076] In the formula C a C b The values ​​represent the concentrations of heavy metal ions before and after adsorption.

[0077] Micro / nano particle removal efficiency (RP, %):

[0078]

[0079] In the formula C a C b The values ​​represent the concentrations of micro- and nano-particles before and after filtration, respectively.

[0080] Bacterial kill efficiency (BP, %):

[0081]

[0082] In the formula C a C b These represent the bacterial concentrations before and after filtration.

[0083] Example 1

[0084] 3g of sodium alginate was dissolved in 200ml of deionized water to prepare an alginate sol. This sol was divided into two portions. 120ml of one portion was mixed with 1g of cellulose and stirred for 2.5h. Then, 1g of aqueous polyurethane was added and stirred for another 2h to obtain the functional layer module sol. The remaining alginate sol was used to prepare the isolation layer module. The functional layer module sol and the isolation layer sol were sprayed separately at a mass ratio of 3:1 onto the surface of ice blocks prepared by freezing 2wt.% calcium chloride crosslinking agent solution at -20℃, solidifying into solid sols. These solid sols were then immersed in a 2.5wt.% calcium chloride solution at 4℃, and after film formation, continued immersion for 1h to obtain a gel. Finally, the gel was freeze-dried at -80℃ for 24h to obtain a modular oil-water separation and purification material containing an isolation layer module and an oil-water separation functional module. The cross-sectional scanning electron microscope image is shown below. Figure 2 As shown, the scanning electron microscope image of the isolation layer module is as follows: Figure 3 As shown in the figure, the scanning electron microscope image of the oil-water separation functional module is as follows: Figure 4 As shown; the thickness of the isolation layer module is 22μm; the thickness of the oil-water separation functional module is 370μm. From Figure 2-4 It can be seen that the isolation layer module has a dense structure, while the oil-water separation functional module has a porous structure with a large specific surface area and high porosity. When the oil-water separation functional module and the isolation layer module are combined together using a calcium alginate matrix, they exhibit ultra-low underwater oil adhesion and roll-off angle, enabling excellent oil-water separation.

[0085] Example 2

[0086] 2g of potassium alginate was dissolved in 200ml of deionized water to prepare an alginate sol, which was divided into two equal portions. One portion was mixed with 3g of ethylenediaminetetraacetic acid (EDTA) and stirred for 2.5h. Then, 2g of aqueous polyurethane was added and stirred for another 3.5h to obtain the functional layer module sol. The remaining alginate sol was used to prepare the isolation layer module. The functional layer module sol and the isolation layer sol were sprayed onto the surface of ice blocks made by freezing 3wt.% calcium chloride crosslinking agent solution at -20℃ at a mass ratio of 4:1, and solidified into solid sols. The solid sols were then immersed in 3wt.% calcium chloride solution at 4℃, and after film formation, they were immersed for another 1h to obtain a gel. The gels were then freeze-dried at -80℃ for 24h to obtain a modular heavy metal wastewater purification material. The thickness of the isolation layer module was 25μm, and the thickness of the heavy metal adsorption functional module was 300μm.

[0087] Example 3

[0088] 3g of ammonium alginate was dissolved in 200ml of deionized water to prepare an alginate sol. This sol was divided into two portions. 80ml of one portion was mixed with 0.5g of polyethyleneimine and stirred for 1 hour. Then, 2g of aqueous polyurethane was added and stirred for another 1 hour to obtain the functional layer module sol. The remaining alginate sol was used to prepare the isolation layer module. The functional layer module sol and the isolation layer sol were sprayed separately at a mass ratio of 4:1 onto the surface of ice blocks prepared by freezing a 3wt.% calcium chloride crosslinking agent solution at -20℃ to solidify into solid sols. These solid sols were then immersed in a 2.5wt.% calcium chloride solution at 4℃, and after film formation, continued immersion for 1 hour to obtain a gel. Finally, the gel was freeze-dried at -80℃ for 24 hours to obtain a modular sterilization material. The isolation layer module had a thickness of 32μm, and the sterilization module had a thickness of 340μm.

[0089] Example 4

[0090] 3g of ammonium alginate was dissolved in 200ml of deionized water to prepare an alginate sol, which was divided into two equal parts. One part was mixed with 3g of polyamine carbide and stirred for 5 hours. Then, 2g of aqueous polyurethane was added and stirred for another 2 hours to obtain the functional layer module sol. The remaining alginate sol was used to prepare the isolation layer module. The functional layer module sol and the isolation layer sol were sprayed at a mass ratio of 7:1 onto the surface of ice blocks prepared by freezing 3wt.% calcium chloride crosslinking agent solution at -20℃ to solidify into solid sols. The solid sols were then immersed in 2wt.% calcium chloride solution at 1℃, and after film formation, they were immersed for another 1 hour to obtain a gel. Then, the gels were freeze-dried at -80℃ for 24 hours to obtain modular micro-nano plastic purification materials. The thickness of the isolation layer module was 34μm, and the thickness of the micro-nano plastic purification module was 355μm.

[0091] Example 5

[0092] 3g of sodium alginate was dissolved in 200ml of deionized water to prepare an alginate sol. This sol was divided into two portions. 110ml of one portion was mixed with 1g of polyethyleneimine and 1g of ethylenediaminetetraacetic acid (EDTA), and stirred for 5 hours. Then, 4g of aqueous polyurethane was added, and stirring continued for 2 hours to obtain the functional layer module sol. The remaining alginate sol was used to prepare the isolation layer module. The functional layer module sol and the isolation layer sol were sprayed at a mass ratio of 8:1 onto the surface of ice blocks prepared by freezing at -20℃ with a 3wt.% calcium chloride crosslinking agent solution to solidify into solid sols. These solid sols were then immersed in a 2.5wt.% magnesium chloride solution at 5℃, and after film formation, continued immersion for 1 hour to obtain a gel. Finally, the gel was freeze-dried at -80℃ for 24 hours to obtain a modular heavy metal purification and sterilization material. The isolation layer module had a thickness of 26μm, and the switchable functional layer module had a thickness of 390μm.

[0093] Example 6

[0094] 3g of sodium alginate was dissolved in 200ml of deionized water to prepare an alginate sol, which was divided into two equal parts. One part was mixed with 1g of polyethyleneimine and 0.5g of cellulose and stirred for 5 hours. Then, 0.5g of aqueous polyurethane was added and stirred for another 2 hours to obtain the functional layer module sol. The remaining alginate sol was used to prepare the isolation layer module. The functional layer module sol and the isolation layer sol were sprayed at a mass ratio of 6:1 onto the surface of ice blocks prepared by freezing at -30℃ with a 2.5wt.% calcium chloride crosslinking agent solution to solidify into solid sols. The solid sols were then immersed in a 2.5wt.% magnesium chloride solution at 5℃ and immersed for another 1 hour to obtain a gel. The gels were then freeze-dried at -80℃ for 24 hours to obtain a modular oil-water separation sterilization material. The thickness of the isolation layer module was 25μm, and the thickness of the switchable functional layer module was 320μm.

[0095] Example 7

[0096] 3g of sodium alginate was dissolved in 200ml of deionized water to prepare an alginate sol. This sol was divided into two portions. 180ml of one portion was mixed with 1g of cellulose, 1g of polyethyleneimine, and 0.5g of polyaniline, and stirred for 2.5h. Then, 2.5g of aqueous polyurethane was added, and stirring continued for 3.5h to obtain the functional layer module sol. The remaining alginate sol was used to prepare the isolation layer module. The functional layer module sol and the isolation layer sol were sprayed at a mass ratio of 6:1 onto the surface of ice blocks prepared by freezing at -20℃ with a 5wt.% calcium chloride crosslinking agent solution to solidify into solid sols. These solid sols were then immersed in a 2.5wt.% calcium chloride solution at 4℃, and after film formation, continued immersion for 1h to obtain a gel. Finally, the gel was freeze-dried at -80℃ for 24h to obtain a modular oil-water separation heavy metal adsorption and sterilization material. The isolation layer module had a thickness of 20μm, and the switchable functional layer module had a thickness of 380μm.

[0097] Example 8

[0098] 3g of sodium alginate was dissolved in 200ml of deionized water to prepare an alginate sol. This sol was divided into two portions. 180ml of one portion was mixed with 1g of cellulose, 0.5g of polyethyleneimine, 0.5g of polyaniline, and 0.5g of chitosan, and stirred for 2.5h. Then, 2.5g of aqueous polyurethane was added, and stirring continued for 3.5h to obtain the functional layer module sol. The remaining alginate sol was used to prepare the isolation layer module. The functional layer module sol and the isolation layer sol were sprayed separately at a mass ratio of 6:1 onto the surface of ice blocks prepared by freezing at -20℃ with a 5wt.% calcium chloride crosslinking agent solution to solidify into solid sols. These solid sols were then immersed in a 2.5wt.% calcium chloride solution at 4℃, and after film formation, continued immersion for 1h to obtain a gel. Finally, the gel was freeze-dried at -80℃ for 24h to obtain a modular oil-water separation heavy metal adsorption micro / nanoplastics purification and sterilization material. The isolation layer module had a thickness of 22μm, and the switchable functional layer module had a thickness of 410μm.

[0099] Example 9

[0100] Dissolve 3g of sodium alginate in 200ml of deionized water to prepare an alginate sol, divide it into three portions, take 80ml of one portion and add 1g of cellulose, stir for 2.5h, then add 1g of waterborne polyurethane and continue stirring for 2h to obtain functional layer module sol 1; take 70ml of the second portion and add 1g of polyethyleneimine and 0.5g of waterborne polyurethane, mix evenly to obtain functional layer module sol 2; the remaining alginate sol is used to prepare the isolation layer module. Functional layer module sol 1, functional layer module sol 2, and isolation layer sol were sprayed onto the surface of ice blocks prepared by freezing 5 wt.% calcium chloride crosslinking agent solution at -20℃ in a mass ratio of 3:3:1, and solidified into solid sols. The solid sols were then immersed in 2.5 wt.% calcium chloride solution at 4℃, and after film formation, they were soaked for another 1 hour to obtain a gel. The gel was then freeze-dried under vacuum at -80℃ for 24 hours to obtain a modular oil-water separation sterilization material. The thickness of the isolation layer module was 20 μm, and the total thickness of the switchable functional layer modules was 710 μm, of which the thickness of the oil-water separation functional module was 370 μm and the thickness of the sterilization module was 340 μm.

[0101] Example 10

[0102] Dissolve 3g of sodium alginate in 200ml of deionized water to prepare an alginate sol, which is divided into four portions. Take 75ml of one portion, add 1g of cellulose, stir for 2.5h, then add 0.5g of aqueous polyurethane and continue stirring for 2h to obtain functional layer module sol 1. Take 50ml of the second portion, add 1g of polyethyleneimine and 0.5g of aqueous polyurethane, and mix evenly to obtain functional layer module sol 2. Take 50ml of the third portion, add 1g of ethylenediaminetetraacetic acid and 1g of aqueous polyurethane, and mix evenly to obtain functional layer module sol 3. The remaining alginate sol is used to prepare the isolation layer module. Functional layer module sol 1, functional layer module sol 2, functional layer module sol 3 and isolation layer sol were sprayed onto the surface of ice blocks prepared by freezing at -20℃ with 5wt.% calcium chloride crosslinking agent solution in a mass ratio of 3:2:2:1 to solidify into solid sols. Then, the solid sols were immersed in 2.5wt.% calcium chloride solution at 4℃, and after film formation, they were soaked for another 1 hour to obtain gels. Then, they were vacuum freeze-dried at -80℃ for 24 hours to obtain modular oil-water separation heavy metal adsorption and sterilization material. The thickness of the isolation layer module is 20μm, and the total thickness of the switchable functional layer modules is 800μm, of which the thickness of the oil-water separation functional module is 330μm, the thickness of the sterilization module is 240μm, and the thickness of the heavy metal adsorption functional module is 230μm.

[0103] Example 11

[0104] 3g of sodium alginate was dissolved in 200ml of deionized water to prepare an alginate sol, which was divided into five equal parts. One part was mixed with 1g of cellulose and stirred for 2.5h, then 0.5g of aqueous polyurethane was added and stirred for another 2h to obtain functional layer module sol 1. The second part was mixed with 1g of polyethyleneimine and 0.5g of aqueous polyurethane to obtain functional layer module sol 2. The third part was mixed with 1g of ethylenediaminetetraacetic acid and 1g of aqueous polyurethane to obtain functional layer module sol 3. The fourth part was mixed with 1g of chitosan and 1g of aqueous polyurethane to obtain functional layer module sol 4. The remaining alginate sol was used to prepare the isolation layer module. Functional layer module sol 1, functional layer module sol 2, functional layer module sol 3, functional layer module sol 4 and isolation layer sol were sprayed onto the surface of ice blocks prepared by freezing at -20℃ with 5wt.% calcium chloride crosslinking agent solution in a mass ratio of 2:2:2:1:1 to solidify into solid sols. Then, the solid sols were immersed in 2.5wt.% calcium chloride solution at 4℃, and after film formation, they were soaked for another 1 hour to obtain gels. Then, they were freeze-dried in vacuum at -80℃ for 24 hours to obtain modular oil-water separation heavy metal adsorption nanoplastic purification and sterilization material. The thickness of the isolation layer module is 20μm, and the total thickness of the switchable functional layer modules is 930μm, of which the thickness of the oil-water separation functional module is 270μm, the thickness of the sterilization module is 210μm, the thickness of the heavy metal adsorption functional module is 230μm, and the thickness of the micro-nanoplastics purification module is 220μm.

[0105] Comparative Example 1

[0106] Compared with Example 1, the difference is that the wastewater purification material does not have an isolation layer module.

[0107] Table 1. Test results of water purification efficiency of wastewater purification materials

[0108]

[0109] According to the test results in the table above, in Comparative Example 1, due to the lack of an isolation layer module, the water flow is large and the pollutants cannot be fully purified, resulting in lower oil-water separation efficiency, heavy metal removal efficiency, and micro-nano particle removal efficiency than the purification material provided by this invention. In Examples 1-4, the single-layer switchable functional layer module with a single function has good removal efficiency in its respective function. In Examples 5-6, the single-layer switchable functional layer module with dual functions has good removal efficiency in both of its respective functional areas, and the effect is also good. In Example 9, the switchable functional layer module has a two-layer structure, specifically an oil-water separation functional module and a sterilization module. Compared with Example 6, its oil-water separation efficiency and sterilization efficiency are improved. This is because the thickness of the switchable functional layer module is increased, the purified water flow is reduced, and the pollutants are purified more thoroughly, but the purification speed is reduced. In Example 7, the switchable functional layer module has triple effects of oil-water separation, heavy metal adsorption, and sterilization, and the effect is also good. In Example 10, the switchable functional layer module has a three-layer structure, and its purification efficiency for various pollutants is greatly improved. This is because the increased thickness of the switchable functional layer module allows pollutants in the water to be better adsorbed and trapped in the functional layer, improving the water purification efficiency, but the purification speed is reduced. Although the switchable functional layer module in Example 8 has only a single-layer structure, it has four functions; the switchable functional layer module in Example 11 has a four-layer structure, and each layer has a different function; the structures and thicknesses of the two are slightly different, which results in the filtration speed of Example 11 being slightly slower than that of Example 8, but both can achieve good purification effects.

[0110] In summary, this invention utilizes a modular wastewater purification material with a modular isolation layer and switchable functional modules, enabling functional switching for different pollutants; furthermore, the preparation method is simple and safe. The resulting modular wastewater purification material can be used directly or combined with a water purification device to achieve targeted purification of wastewater.

[0111] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A modular wastewater purification material, characterized in that, The modular wastewater purification material includes: an isolation layer module and a switchable functional layer module. The switchable functional layer module is a single-layer or multi-layer structure, including one or more of the following: an oil-water separation functional module, a heavy metal adsorption functional module, a sterilization functional module, and a micro-nano plastic purification module. The preparation method of the modular wastewater purification material includes the following steps: dissolving alginate in deionized water to prepare alginate sol, dividing it into N parts, where N≥2; in the first to N-1th rounds of spraying, taking one part in each round and adding a modifier and a pore-forming agent to obtain a functional layer module sol, and using spraying to solidify the functional layer module sol on the surface of crosslinking agent ice to obtain a modular functional layer crude product; covering the surface of the functional layer crude product with the Nth part of alginate sol through the Nth round of spraying, and then immersing it in a crosslinking agent solution to obtain a modular wastewater purification material crude product, and then using vacuum freeze-drying to obtain a modular wastewater purification material including an isolation layer module and a switchable functional layer module.

2. The modular wastewater purification material according to claim 1, characterized in that, The isolation layer module is a dense structure, and the surface potential is a negative potential; the switchable functional layer module is a porous structure, and the surface potential is a positive potential, and the specific surface area is 220-300 m 2 / g, and the porosity is 25-50%.

3. The modular wastewater purification material according to claim 1, characterized in that, The surface pore size of the isolation layer module is 1~5nm; the surface pore size of the switchable functional layer module is 40~55μm.

4. The modular wastewater purification material according to claim 1, characterized in that, The thickness of the isolation layer module is 20~50μm; the thickness of the switchable functional layer module is 100~1900μm.

5. The modular wastewater purification material according to claim 1, characterized in that, The switchable functional layer module is prepared from raw materials including alginate, modifier, and pore-forming agent.

6. The modular wastewater purification material according to claim 5, characterized in that, The mass ratio of alginate, modifier, and pore-forming agent is 1:(0.1~3):(0.1~3).

7. The modular wastewater purification material according to claim 5, characterized in that, The pore-forming agent is waterborne polyurethane.

8. The modular wastewater purification material according to claim 5, characterized in that, The modifier includes one or more of the following: polycarboxyamine, chitosan, cellulose, carboxymethyl cellulose, citric acid, sodium citrate, ethylenediaminetetraacetic acid, tetraethylenepentamine, sodium lignosulfonate, polyaniline, penicillamine, polyethyleneimine, polymethyl methacrylate, and sulfobetaine methacrylate.

9. The modular wastewater purification material according to claim 1, characterized in that, The modifier in the oil-water separation module includes one or more of sodium citrate, cellulose, and carboxymethyl cellulose.

10. The modular wastewater purification material according to claim 1, characterized in that, The modifier in the heavy metal adsorption module includes one or more of ethylenediaminetetraacetic acid, polyaniline, citric acid, and tetraethylenepentamine.

11. The modular wastewater purification material according to claim 1, characterized in that, The modifier in the sterilization module includes one or more of polyethyleneimine, penicillamine, polymethyl methacrylate, and sodium lignosulfonate.

12. The modular wastewater purification material according to claim 1, characterized in that, The modifiers in the micro-nano plastic purification module include one or more of polycarboxylated amine, chitosan, and sulfobetaine methacrylate.

13. A method for preparing the modular wastewater purification material as described in claim 1, characterized in that, The preparation method includes the following steps: dissolving alginate in deionized water to prepare alginate sol, dividing it into N parts, where N≥2; in the first to N-1th rounds of spraying, taking one part in each round and adding a modifier and a pore-forming agent to obtain a functional layer module sol, and using spraying to solidify the functional layer module sol on the surface of crosslinking agent ice to obtain a modular functional layer crude product; covering the surface of the functional layer crude product with the Nth part of alginate sol through the Nth round of spraying, and then immersing it in a crosslinking agent solution to obtain a modular wastewater purification material crude product, and then using vacuum freeze-drying to obtain a modular wastewater purification material including an isolation layer module and a switchable functional layer module.

14. The application of a modular wastewater purification material as described in claim 1 in wastewater treatment.

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