Modified fiber filter material, preparation method thereof and filter tank

Abstract

The invention relates to the technical field of filter materials, in particular to a modified fiber filter material, a preparation method thereof and a filter tank. According to the modified fiber filter material provided by the invention, a structure shown in a formula (I) is grafted on the fiber filter material, in the formula (I), R1 is (CH2) n, the value range of n is 2-3, R2, R3 and R4 are independently selected from C1-C2 alkyl groups, R5 and R6 are independently selected from hydrogen and C1-C18 alkyl groups, and R7 is independently selected from at least one of C1-C18 alkyl groups or C1-C18 aromatic groups. The invention provides a group structure with strong hydrophobicity and antibacterial property, which is beneficial to backwashing removal of pollutants, the hydrophobic surface can also reduce microbial attachment and biofilm formation, the biofilm structure on the surface of the fiber filter material can also be destroyed by using the synthesized quaternary ammonium group, the backwashing effect and regeneration capacity of the fiber filter material are improved, and the fiber filter material can be recycled. And long-term stable operation of the rapid filtering technology is maintained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of filter material, in particular to a modified fiber filter material and a preparation method and filter tank thereof. BACKGROUND

[0002] The rapid filtration technology is a commonly used means in the wastewater treatment system, wherein the adsorption capacity and the backwashing desorption effect of the filter material are important bases for the rapid filtration treatment technology. Compared with the traditional filter materials such as quartz sand, ceramic ball and zeolite, the fiber filler has stronger adsorption performance and filtration effect and is widely used. However, the fiber filter material used at present is prone to adsorption site pollution and clogging after being used for many times, and it is difficult to achieve good regeneration effect through the traditional backwashing process, which reduces the service life and the pollutant removal capacity of the fiber filter material. Improving the regeneration performance of these high-performance fiber fillers is crucial to maintaining the stability of the treatment system. At the same time, due to the good biological adhesion of the fiber filter material, microorganisms are prone to adhere to the surface to form a biofilm during the water treatment process, which reduces the contact between the filter material and the water interface, and further affects the backwashing desorption effect of the filter material, resulting in a decrease in the water treatment removal effect. Therefore, the desorption and regeneration performance of the rapid filtration material has become the main limiting factor restricting the application and development of the rapid filtration technology.

[0003] At present, in view of the poor desorption and backwashing effect of the rapid filtration filter material, the air-water backwashing technology is mainly improved by improving the filter tank structure, adjusting the aeration mode, increasing the backwashing frequency and prolonging the backwashing time, etc. to improve the backwashing effect of the filter material. However, this kind of solution needs to modify the structure of the rapid filtration filter tank or the aeration and backwashing pipeline, or needs to increase the backwashing energy consumption in the daily operation, which has the problems of high cost and long cycle in the actual application. Moreover, after modification, the filtration effect can only be improved in the process operation, and the fundamental problems of filter clogging and biofilm adhesion are not solved. SUMMARY

[0004] Therefore, in order to solve the above problems, the present application provides a modified fiber filter material and a preparation method and filter tank thereof.

[0005] Therefore, the present application provides a modified fiber filter material, wherein the fiber filter material is grafted with a structure shown in formula (I),

[0006] Formula (I), wherein R1 in formula (I) is (CH2) n n is 2-3, R2, R3 and R4 are independently selected from C1-C2 alkyl, R5, R6are independently selected from hydrogen, C1-C18 alkyl, R7is independently selected from at least one of C1-C18 alkyl or C1-C18 aromatic group.

[0007] Optionally, the R1is propylene; R5, R6are independently selected from C1-C3 alkyl; R7includes at least one of C12-C18 alkyl or C12-C18 aromatic group.

[0008] Optionally, the R7includes at least one of dodecyl, hexadecyl, octadecyl and benzyl.

[0009] The preparation method of the structure shown in formula (I) comprises the following steps, mixing, heat treating and emulsifying the compound shown in formula (II) and the compound shown in formula (III) to obtain an amino silicone oil emulsion with quaternary ammonium salt group,

[0010] Formula (II), wherein R1is (CH2) n , n is in the range of 2-3, R2, R3, R4are independently selected from C1-C2 alkyl, R8, R9are independently selected from hydrogen, C1-C18 alkyl;

[0011] Formula (III), wherein R7is at least one of C1-C18 alkyl, benzyl; X includes at least one of Cl - , Br - , I - , CH3SO4 - .

[0012] Optionally, R8, R9include at least one of hydrogen, methyl and ethyl; The compound shown in formula (II) includes at least one of (N,N-dimethyl-3-aminopropyl)trimethoxysilane, (N-methyl-3-aminopropyl)trimethoxysilane and (N,N-diethyl-3-aminopropyl)trimethoxysilane; The compound shown in formula (III) includes at least one of benzyl chloride, halide-substituted hexadecane, halide-substituted dodecane and halide-substituted octadecane; and / or, the molar ratio of the compound shown in formula (II) and the compound shown in formula (III) is 1:(1.1-1.3). The step of heat treatment is specifically mixing the compound with the structure shown in formula (II) and the organic solvent according to a mass ratio of 1: (1.5-2), adding the compound with the structure shown in formula (III) to obtain a mixture, heat treating the mixture at a first temperature for a first time, and then heat treating the mixture at a second temperature for a second time, wherein the first temperature is 70-80℃, the first time is 4-5h, the second temperature is 80-90℃, and the second time is 1-2h. The step of emulsification comprises adjusting the pH value of the mixture after heat treatment to 5-6, and then adjusting the temperature of the mixture to 80-85℃ under stirring, wherein the stirring speed is 300-500 rpm and the stirring time is 10-15 min.

[0013] In a second aspect, the present application provides a preparation method of the modified filter material, comprising the following steps, S1, activating the pretreated filter material; S2, mixing the compound with the structure shown in formula (I) and the organic solvent to form a reaction system, and immersing the activated filter material in the reaction system to obtain the modified filter material.

[0014] In step S1, the method for activating the pretreated filter material comprises at least one of chemical oxidation, acid washing, alkali washing, plasma treatment or ray irradiation. In step S1, the pretreatment of the filter material comprises ultrasonic treatment, cleaning and drying. The step of activating the pretreated filter material comprises irradiating the filter material with 40-50W ultraviolet light for 30-45 min. The high energy of the ultraviolet light can effectively excite the chemical bond breakage on the surface of the filter material, especially the original chemical bond in the macromolecular chain of the amorphous region of cellulose, thereby generating a large number of reaction sites and active groups (such as -COOH, -OH, -COO-, etc.). The above active groups can significantly enhance the binding ability between the filter material and the modifier, and improve the stability and durability of the modification effect.

[0015] In step S2, the volume ratio of the compound with the structure shown in formula (I) to the organic solvent is 1:1-1.2. In step S2, the organic solvent comprises at least one of methanol, ethanol and isopropanol. In step S2, the reaction temperature is 50-65℃, the reaction time is 4-6h, and the stirring speed is 80-150 rpm. The preparation method of the modified filter material further comprises the steps of cleaning and drying the modified filter material.

[0016] Thirdly, the present invention provides a filter bed in which the fiber filter media is the modified fiber filter media described above or the modified fiber filter media prepared by the above-mentioned method.

[0017] The modified fiber filter media filling amount in the filter tank is 75-90%; And / or, the filter tank is equipped with a rotary stirring device.

[0018] The technical solution of this invention has the following advantages: 1. The modified fiber filter media provided by the present invention, wherein the fiber filter media is grafted with the structure shown in formula (Ⅰ),

[0019] In equation (Ⅰ), R1 is (CH2). n The value of n ranges from 2 to 3. R2, R3, and R4 are independently selected from C1-C2 alkyl groups. R5 and R6 are independently selected from hydrogen and C1-C18 alkyl groups. R7 is independently selected from at least one of C1-C18 alkyl groups or C1-C18 aromatic groups.

[0020] This invention provides a group structure with strong hydrophobicity and antibacterial properties. Grafting this structure onto fiber filter media not only facilitates the backwashing removal of solid particles and other pollutants, but the hydrophobic surface can also reduce microbial adhesion and biofilm formation to a certain extent. Furthermore, the functional group grafting not only further enhances the hydrophobic properties, but also utilizes the synthesized quaternary ammonium groups with strong antibacterial capabilities to disrupt the biofilm structure on the surface of the fiber filter media, thereby improving the backwashing effect and regeneration capacity of the fiber filter media and maintaining the long-term stable operation of the rapid filtration technology.

[0021] 2. The present invention provides a modified fiber filter material, wherein the preparation method of the structure shown in formula (I) includes the following steps: S1, mixing, heat-treating, and emulsifying the compound shown in formula (II) and the compound shown in formula (III) to obtain an amino silicone oil emulsion with quaternary ammonium salt groups.

[0022] Formula (II), Where R1 is (CH2) n The value of n ranges from 2 to 3, R2, R3, and R4 are independently selected from C1-C2 alkyl groups, and R8 and R9 are independently selected from hydrogen and C1-C18 alkyl groups.

[0023] Formula (Ⅲ), wherein R7 is at least one of C1-C18 alkyl or benzyl groups; X is a C1-C18 alkyl group. - ,Br - I- CH3SO4 - At least one of them.

[0024] This invention utilizes the reaction of compounds shown in formulas (II) and (III) to reduce the introduction of hydrophilic groups such as hydroxyl groups. By using long-chain alkanes and quaternary ammonium functional groups, the hydrophobic and antibacterial properties of the compounds with the final structure shown in formula (I) are improved. This results in fiber filter media grafted with this group having better hydrophobic and antibacterial properties, which can promote the desorption of solid particulate pollutants and reduce the adhesion of microbial films, thereby improving the backwashing effect of the filter media.

[0025] 3. The present invention provides a modified fiber filter material, wherein the heat treatment step specifically involves mixing a compound with the structure shown in formula (II) and an organic solvent at a mass ratio of 1:1.5-2, adding the compound shown in formula (III) to obtain a mixture, heat-treating at a first temperature for a first time, and then heat-treating at a second temperature for a second time. The first temperature is 70-80°C, the first time is 4-5 hours, the second temperature is 80-90°C, and the second time is 1-2 hours. The present invention employs a staged heating process, which not only effectively controls the reaction rate and avoids local overheating leading to side reactions, but also improves the conversion rate of the product.

[0026] 4. The present invention provides a method for preparing modified fiber filter media, comprising: S1, activating the pretreated fiber filter media; S2, mixing the compound with the structure shown in formula (Ⅰ) and an organic solvent to form a reaction system, immersing the activated fiber filter media in the reaction system to obtain the modified fiber filter media. The present invention, through activation treatment, generates active groups that significantly enhance the binding ability of the fiber filter media with the modifier, improve the stability and durability of the modification effect, promote the desorption of solid particulate pollutants and reduce the adhesion of microbial films, and improve the backwashing effect of the filter media. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is a process flow diagram of a method for preparing modified fiber filter media provided in Embodiment 1 of the present invention; Figure 2 This is an infrared scan image of the modified fiber filter material provided in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the filter structure provided in the application example of the present invention; Explanation of reference numerals in the attached figures: 1. Screw-hole modified fiber filter media; 2. Rotary stirring device; 3. Backwashing aeration device; 4. Drainage outlet; 5. Water inlet; 6. Water outlet. Detailed Implementation

[0029] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0030] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0031] Example 1 Reference Figure 1 As shown in the figure, this embodiment provides a method for preparing modified fiber filter media, and the specific steps and parameters are as follows: (1) A solution of (N,N-dimethyl-3-aminopropyl)trimethoxysilane was formed by mixing (N,N-dimethyl-3-aminopropyl)trimethoxysilane and isopropanol in a mass ratio of 1:2 to that of the compound shown in formula (II). A molar ratio of the compound shown in formula (II) to that of the compound shown in formula (III) was 1:1.2. The compound hexadecane shown in formula (III) was added to the solution of (N,N-dimethyl-3-aminopropyl)trimethoxysilane. The mixture was stirred for 4 min at a speed of 250 rpm. The well-stirred mixture was initially reacted at 75°C for 5 hours, then the temperature was increased to 85°C and the reaction continued for 2 hours. After the reaction was completed, the pH of the reaction system was adjusted to 6 using glacial acetic acid. The temperature of the reaction system was then increased to 85°C, and deionized water was slowly added to the reaction system at a constant stirring speed of 45 wt% for 12 minutes to allow the system to undergo a self-emulsification process. After cooling, an amino silicone oil emulsion with quaternary ammonium salt groups was formed.

[0032] (2) Select columnar porous fiber filter media (the specific gravity of the filter media is about 1.38~1.4, the porosity is 85%~95%, and the specific surface area is about 3000~6000 m²). 2 / m 3The fiber filter media was placed in an ultrasonic cleaning device and cleaned with ultrasonic waves at a frequency of 40kHz for 20 minutes. The cleaning medium was deionized water. After ultrasonic cleaning, the filter media was cleaned twice with deionized water. The fiber filter media was then dried in a constant temperature drying oven at a temperature of 55℃ for 5 hours to obtain clean fiber filter media. The fiber filter media was irradiated with 40W ultraviolet light (wavelength 254nm) for 40 minutes. During the irradiation process, after activation was completed, the fiber filter media was promptly transferred to a sealed container to obtain activated fiber filter media.

[0033] (3) Mix 50 vol% ethanol aqueous solution and amino silicone oil emulsion with quaternary ammonium salt groups at a volume ratio of 1:1 to obtain a mixture. Treat the mixture with 30 KW ultrasonic power for 5 min to obtain a reaction system.

[0034] (4) Immerse the activated fiber filter material obtained in step (2) into the reaction system and react for 6 hours under stirring conditions. The stirring speed is 90 rpm and the reaction temperature is 60℃. After the reaction is completed, rinse once with deionized water and then treat with ultrasonic power of 40W for 10 minutes. After treatment, dry the modified fiber filter material in a constant temperature drying oven for 5 hours. During the drying process, the air inside the oven needs to be kept circulating. The temperature of the constant temperature drying oven is 60℃ to obtain the modified fiber filter material.

[0035] Infrared scanning of modified fiber filter media, see [link / reference]. Figure 2 Therefore, 1450~1600cm -1 The presence of characteristic peaks with quaternary ammonium salt functional groups demonstrates that the method provided in this embodiment can modify and introduce compounds with quaternary ammonium salt groups.

[0036] Example 2 This embodiment provides a method for preparing modified fiber filter material. The specific steps and parameters are the same as in Example 1. The difference is that an equimolar amount of (N,N-dimethyl-3-aminopropyl)trimethoxysilane is used to replace (N,N-dimethyl-3-aminopropyl)trimethoxysilane in step (1), and an equimolar amount of benzyl chloride is used to replace hexadecane bromo in step (1).

[0037] Comparative Example 1 This comparative example provides a method for preparing modified fiber filter media. The only difference between this comparative example and Example 1 is that steps (1), (3), and (4) are omitted.

[0038] Application Examples 1-3 See Figure 3As shown in the illustration, this application example provides a filter bed, which includes a physical filter unit filled with modified fiber filter media 1 at a filling rate of 80 vol%. The physical filter unit is equipped with a rotary stirring device 2, a backwashing aeration device 3 at its bottom, an inlet 5 on one side of its bottom, and an outlet on one side of its top. The filter bed also includes a sludge treatment unit with a drain outlet 4 for discharging sludge.

[0039] When treating wastewater, the wastewater enters the filter tank through the inlet 5, and after being treated by the modified fiber filter media 1, the treated wastewater flows out through the outlet 6, and the sludge remaining in the wastewater flows out through the drain outlet 4.

[0040] This application example uses an air-water backwashing method. After stopping the water intake, the filter tank is emptied, cleaning water is pumped into the backwash storage tank, and the backwash aeration device 3 (fan air volume of 0.5 m³ / s) is turned on. 3 / min, air flushing intensity is 0.5 m 3 / (m 2 (min) parameters), set the rotary stirring device 2 to forward stirring (clockwise, speed 80~100 rpm), aerate and rotate backwash for 10min; drain the filter, pump the cleaning water into the backwash storage tank, turn on the aeration device, set the rotary stirring device to reverse rotation (counterclockwise, 80~100 rpm), aerate and rotate backwash for 10min, drain the filter, and complete the backwashing procedure.

[0041] In Application Examples 1-3, the modified fiber filter media are the modified fiber filter media formed in Examples 1-2 and the unmodified porous fiber filter media provided in Comparative Example 1, respectively.

[0042] Experimental Example The filtration rate, removal rate of suspended solids (SS) and chemical oxygen demand (COD) of the wastewater in corresponding use cases 1-3, as well as the removal rate of suspended solids (SS) and chemical oxygen demand (COD) of the wastewater after 150 backwashes, were tested. The results are shown in Table 1.

[0043] Filtration rate testing method: Filtration rate = water volume processed / cross-sectional area of ​​the filter device, where the water volume processed is usually expressed in cubic meters per hour (m²). 3 The cross-sectional area of ​​the filter device is usually calculated as the internal bottom area, typically expressed in square meters (m²). 2 )calculate.

[0044] Method for detecting suspended solids (SS) removal rate: SS levels before and after rapid filtration are detected by the national standard gravimetric method (GB 11901-89). SS removal rate = (SS... 前 -SS后 ) / SS 前 ×100%.

[0045] Chemical oxygen demand (COD) removal rate testing method: COD before and after rapid filtration is tested using the national standard dichromate method (HJ828-2017). COD removal rate = (COD + COD + COD) / COD + ... 前 -COD 后 COD 前 ×100%.

[0046] Table 1 Wastewater Treatment Performance

[0047] As shown in Table 1, compared with unmodified porous fiber filter media, the fiber filter media provided by the present invention can effectively improve the removal rate of SS and COD in wastewater, and in particular, can extend the service life of the fiber filter media and maintain the long-term stable operation of rapid filtration technology.

[0048] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A modified fiber filter media, characterized in that, The fiber filter media is grafted with the structure shown in formula (Ⅰ). Equation (Ⅰ), In equation (Ⅰ), R1 is (CH2). n The value of n ranges from 2 to 3. R2, R3, and R4 are independently selected from C1-C2 alkyl groups. R5 and R6 are independently selected from hydrogen and C1-C18 alkyl groups. R7 is independently selected from at least one of C1-C18 alkyl or C1-C18 aromatic groups.

2. The modified fiber filter material according to claim 1, characterized in that, R1 is propylidene; R5 and R6 are independently selected from C1-C3 alkyl groups; R7 includes at least one of a C12-C18 alkyl group or a C12-C18 aromatic group.

3. The modified fiber filter material according to claim 2, characterized in that, The R7 includes at least one of dodecyl, hexadecyl, octadecyl, and benzyl.

4. The modified fiber filter media according to any one of claims 1-3, characterized in that, The preparation method of the structure shown in formula (Ⅰ) includes the following steps. The compound with the structure shown in formula (II) and the compound shown in formula (III) are mixed, heat-treated, and emulsified to obtain an amino silicone oil emulsion with quaternary ammonium salt groups. Formula (II), Where R1 is (CH2) n The value of n ranges from 2 to 3. R2, R3, and R4 are independently selected from C1-C2 alkyl groups. R8 and R9 are independently selected from hydrogen-containing, C1-C18 alkyl groups; Formula (Ⅲ), Wherein, R7 is at least one of C1-C18 alkyl and benzyl groups; X includes Cl - ,Br - I - CH3SO4 - At least one of them.

5. The modified fiber filter material according to claim 4, characterized in that, R8 and R9 include at least one of hydrogen, methyl, and ethyl; The compounds with the structure shown in formula (II) include at least one of (N,N-dimethyl-3-aminopropyl)trimethoxysilane, (N-methyl-3-aminopropyl)trimethoxysilane, and (N,N-diethyl-3-aminopropyl)trimethoxysilane; The compounds of formula (III) include at least one of benzyl chloride, halosubstituted hexadecane, halosubstituted dodecane, and halosubstituted octadecane.

6. The modified fiber filter material according to claim 4, characterized in that, The molar ratio of the compound with the structure shown in formula (II) to the compound shown in formula (III) is 1:(1.1-1.3); And / or, the heat treatment step specifically involves mixing the compound with the structure shown in formula (II) and an organic solvent at a mass ratio of 1:1.5-2, adding the compound shown in formula (III) to obtain a mixture, heat-treating at a first temperature for a first time, and then heat-treating at a second temperature for a second time, wherein the first temperature is 70~80℃, the first time is 4-5h, the second temperature is 80~90℃, and the second time is 1~2h; And / or, the emulsification step includes adjusting the pH of the heat-treated mixture to 5-6, and then, under stirring conditions, adjusting the temperature of the mixture to 80-85°C, stirring at a speed of 300-500 rpm, and stirring for 10-15 minutes.

7. A method for preparing the modified fiber filter material according to any one of claims 1-6, characterized in that, Includes the following steps, S1 activates the pretreated fiber filter media; S2, the compound with the structure shown in formula (Ⅰ) and an organic solvent are mixed to form a reaction system, and the activated fiber filter material is immersed in the reaction system to obtain the modified fiber filter material.

8. The method for preparing the modified fiber filter material according to claim 7, characterized in that, The method for activating the pretreated fiber filter material in step S1 includes at least one of chemical oxidation, acid washing, alkaline washing, plasma treatment, or radiation. And / or, the pretreatment step of the fiber filter material in step S1 includes ultrasonic treatment, washing, and drying of the fiber filter material; And / or, in step S2, the volume ratio of the compound with the structure shown in formula (Ⅰ) to the organic solvent is 1:1-1.2; And / or, the organic solvent in step S2 includes at least one of methanol, ethanol, and isopropanol; And / or, under stirring conditions, the activated fiber filter material is immersed in the reaction system at a reaction temperature of 50~65℃, a reaction time of 4~6h, and a stirring speed of 80~150rpm; And / or, the method for preparing the modified fiber filter media further includes the steps of cleaning and drying the modified fiber filter media.

9. A filter bed, characterized in that, The fiber filter media in the filter bed is the modified fiber filter media according to any one of claims 1-6 or the modified fiber filter media prepared by the method of the modified fiber filter media according to any one of claims 7-8.

10. The filter according to claim 9, characterized in that, The modified fiber filter media filling amount in the filter tank is 75-90%; And / or, the filter tank is equipped with a rotary stirring device.

Images