Preparation method and application of activated carbon fiber paper-based water purification material

Abstract

The application discloses a preparation method and application of an activated carbon fiber paper-based water purification material. The material comprises activated carbon fibers, activated carbon particles, synthetic fibers and functional particles. The application also discloses a preparation method of the activated carbon fiber paper-based water purification material and a use method of the material in the water purification field. The activated carbon fiber paper-based water purification material is prepared by using a wet forming technology, the synthetic fibers are used as particle capturing agents to improve the overall bonding strength of the material, the activated carbon fibers and the activated carbon particles can fully play the adsorption effect, and the functional particles can realize the sterilization effect. The paper-based water purification material prepared by using the special wet process can make the raw material components have better effect and higher efficiency, and greatly increase the treatment capacity. The material can expand the water purification performance range, remove more harmful substances, remove chlorine and decolorize water, and has the effects of bacteriostasis and scale inhibition, and is a high-efficiency water purification material.

Description

Technical Field

[0001] This invention belongs to the field of paper-based materials technology, specifically relating to an activated carbon fiber paper-based water purification material. Background Technology

[0002] Water is the source of life. With the increasing scarcity of freshwater resources and the impact of water pollution, humanity faces the danger of having no drinking water available in the long run. Therefore, the importance of wastewater treatment and water purification technologies is becoming increasingly prominent. Water purifiers, as essential equipment for ensuring drinking water safety in homes and public places, rely heavily on the performance of their core component—the filter cartridge—to determine the purification effect. Currently, commonly used filter cartridges on the market include polypropylene melt-blown filter cartridges (PP cotton), activated carbon filter cartridges, ultrafiltration membrane filter cartridges, and reverse osmosis membrane filter cartridges. Regardless of the type of filter cartridge, activated carbon is an indispensable component, playing a role in removing odors and dechlorinating.

[0003] Common activated carbon filter cartridges for water treatment are relatively simple in variety. Generally, in addition to activated carbon, binders and forming agents are added to the raw materials. This is crucial for the formation of activated carbon filter cartridges; the binder can shape the amorphous activated carbon material and improve the strength of the filter cartridge. Currently, most binders used in activated carbon filter cartridges on the market are resins and inorganic binders. These binders may cause clogging of the filter pores, reducing filter efficiency. Furthermore, the current domestic production technology for activated carbon filter cartridges is dry forming technology (sintered carbon rods). This method has significant limitations in material selection, being suitable only for granular materials and lacking micro-filter manufacturing processes. It cannot form fibrous filter media and requires heat-resistant raw materials. Although the operation is simple and the cost is low, the production speed is slow, the manufacturing process has extremely high requirements for the workshop, and if not done properly, it can cause significant environmental pollution and consume a lot of energy. In addition, although some people use aramid pulp and PBO pulp to effectively enhance the strength of composite materials, aramid and PBO fibers are expensive, while PAN fiber is inexpensive. Therefore, using PAN pulp as a binder is worth considering. Functional activated carbon water purification materials with bactericidal properties targeting common bacterial species are scarce on the market, yet there is a large market demand. Conventional water purifiers use reverse osmosis membranes for sterilization. While this method removes bacteria, viruses, and other harmful substances from the water, it also removes beneficial minerals and trace elements. Furthermore, these purifiers require pressurized water to pass through the reverse osmosis membrane, consuming electricity and limiting their application. Additionally, the filter cartridges need regular replacement to prevent clogging and a decline in water quality. Therefore, this invention, a functional activated carbon water purification material, is a bactericidal adsorption material targeting common bacterial species, and there is a significant market demand for it. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention uses PAN pulp as a binder and employs a wet molding process to prepare activated carbon fiber paper-based water purification materials. When PAN pulp is mixed with certain fiber materials and granular powder materials, the interweaving and entanglement of microfibers forms a 3D network structure, significantly improving the overall bonding strength of the material. The wet molding ignition system overcomes the drawbacks of traditional "dry molding," such as the high-temperature extrusion required and the limited material selection. It allows for the use of more diverse water purification raw materials, expanding the range of water purification performance and removing more harmful substances. The special adsorption and bonding process also increases the efficiency of raw material utilization, greatly increasing processing capacity and achieving antibacterial and scale-inhibiting effects. The unique process also facilitates the production of products of different sizes and shapes. This improves the adsorption capacity of the activated carbon fiber paper-based water purification material. Furthermore, due to the addition of polypropylene pulp, the activated carbon fiber paper-based water purification material prepared by the wet molding ignition system features excellent adsorption effect, high strength, low density, acid and chemical corrosion resistance, good water flux, and low production cost.

[0005] A method for preparing an activated carbon fiber paper-based water purification material, comprising, by mass percentage, 5%-25% activated carbon fiber, 10%-30% activated carbon particles, 15%-30% synthetic fiber, and 5%-20% functional particles.

[0006] Preferably, the activated carbon fiber is one or more of the following: viscose-based activated carbon fiber, polyacrylonitrile-based activated carbon fiber, pitch-based activated carbon fiber, phenolic-based activated carbon fiber, polyvinyl alcohol-based activated carbon fiber, natural fiber-based activated carbon fiber, and lignin-based activated carbon fiber.

[0007] Preferably, the activated carbon fiber has a diameter of 5-20 μm and a length of 2-5 mm, more preferably 8 μm or 3 mm.

[0008] Preferably, the activated carbon particles are one or more of coconut shell activated carbon, fruit shell activated carbon, peach shell activated carbon, apricot shell activated carbon, and coal-based activated carbon.

[0009] Preferably, the activated carbon particles have a mesh size of 300-800 mesh, and more preferably 500 mesh.

[0010] Preferably, the synthetic fiber includes one or more of polyacrylonitrile fiber, bicomponent PET fiber, and core-sheath layer PP / PE. Each fiber has a fineness of 1.5-3D and a length of 3-5mm.

[0011] Preferably, the functional particles include alumina particles or titanium dioxide particles.

[0012] Preferably, the length of the synthetic fiber is 3-10 mm; the surface treatment agent is a sodium hydroxide aqueous solution with a mass concentration of 10%-30%; the pretreatment time is 12-24 h; the pretreated synthetic fiber is rinsed with water until neutral; the synthetic fiber is dispersed in water to form a suspension with a mass concentration of 5-20%.

[0013] Preferably, the pulp has a fiber length of 1.5-3 mm and an aspect ratio of 100-150:1, and the surface of the pulp has microfibers; the pulp has a Shore freeness of 25-51°SR, a Canadian freeness of 180-680 mL, and a specific surface area of ​​25-50 m². 2 / g.

[0014] Preferably, the forming device is an inclined wire paper machine or a cylinder paper machine, with a machine speed of 50-100 m / s and a paper basis weight of 60-250 g / m². 2 The drying temperature is 120-140℃.

[0015] This invention also provides a method for preparing the activated carbon fiber paper-based water purification material, comprising the following steps:

[0016] a. Pulp preparation: Synthetic fibers are pretreated with a surface treatment agent, and then dispersed and ground to obtain pulp.

[0017] b. Mixing: Use a trough pulper to mix pulp with 300-800 mesh activated carbon fiber, synthetic fiber, activated carbon granules and functional granules. After mixing, add water to the raw materials to obtain a 10% concentration suspension.

[0018] c. Papermaking: The suspension is pumped to the pulp tower and then the proportion is adjusted in the batching tank. It is then pumped to the forming machine for forming. After forming, it is dehydrated, dried, and cooled to obtain activated carbon fiber paper-based water purification material.

[0019] d. Post-processing: The activated carbon fiber paper-based water purification material is slit, folded, and glued to form a filter element.

[0020] This invention employs a wet-process molding technique to prepare activated carbon fiber paper-based water purification materials. Synthetic fibers act as particle trapping agents, enhancing the overall bonding strength of the material. The activated carbon fibers and particles fully utilize their adsorption capacity, while functional particles achieve a bactericidal effect. This invention's unique wet-process preparation of the paper-based water purification material improves the effectiveness and efficiency of the raw material components, significantly increasing treatment capacity. The material of this invention expands the range of water purification performance, removes more harmful substances, dechlorinates and decolorizes water, and also has antibacterial and scale-inhibiting effects, making it a highly efficient water purification material.

[0021] The purification material described in this invention can achieve the following technical indicators:

[0022] ① Sensory requirements: The appearance is clean, without obvious scratches, dirt, or leakage of functional particles.

[0023] ② Initial flow rate: Under a working pressure of 0.1MPa, the initial flow rate is ≥3L / min, tested in a 3-point pipe.

[0024] ③ Residual chlorine: The free chlorine concentration was determined to be ≤2 mg / L using the N,N-diethyl-p-phenylenediamine (DPD) spectrophotometric method.

[0025] ④ Decolorization effect: The mass of materials required for decolorization was determined using caramel stock solution of method A, and XA < 0.8.

[0026] ⑤ Sterilization effect: The pulp was made into filter paper with a density of 50g / m2 and a control experiment was conducted to filter Escherichia coli suspension. The plate count method was used to determine that the filter paper made of HFPAN-TiO2 had a good sterilization effect.

[0027] ⑥ Hygiene and safety requirements: Comply with the "Hygiene and Safety Evaluation Standard for Drinking Water Transmission and Distribution Equipment and Protective Materials" (2001).

[0028] Compared with the prior art, the beneficial effects of this invention include:

[0029] The pulp prepared by this invention has good fibrillation effect, with fiber length maintained at 1.5-3mm and aspect ratio of 100-150:1. The pulp has a large number of hydrogen bonds, good fiber bonding force, good dispersibility, and uniform structure. Furthermore, the new grinding disc can reduce grinding energy consumption and improve production efficiency.

[0030] The polyacrylonitrile pulp prepared by this invention can be used as a binder in the wet manufacturing of filter cartridges. The resulting water purification material exhibits excellent hydrophilicity, high water output, and strong adsorption capacity, effectively removing residual chlorine, odors, and dyes without producing black water or shedding carbon powder. Furthermore, its structure is more stable and elastic, preventing the carbon layer of the filter cartridge from breaking due to severe vibration during transportation. Attached Figure Description

[0031] Figure 1 A process flow diagram for the preparation of activated carbon fiber paper-based water purification materials. Specific implementation methods

[0032] The described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0033] Example 1

[0034] Pre-treating polyacrylonitrile (PA) chopped fibers with a 20% sodium hydroxide solution for 24 hours; dispersing PA fibers in water to form a 20% suspension; grinding the fibers in a disc mill (the disc mill system consists of three double-disc mills connected in series, with the gap between the first mill 0.5mm, the second 0.3mm, and the third 0.15mm) to fibrillate the chopped fibers while maintaining the length of the pulp fibers, forming pulp; dewatering and storing the pulp. Using a trough pulper, 10% by weight of the prepared pulp is mixed with 20% PA-based activated carbon fiber, 30% bicomponent PET fiber, 30% coconut shell activated carbon granules, and 10% alumina granules. Water is added to the mixture to form a 10% suspension. The suspension is pumped to a pulp tower and then through a batching tank, where the suspension delivery ratio is adjusted according to different process requirements. Finally, it is pumped to a forming device for forming, followed by dewatering, drying, and cooling to obtain activated carbon fiber paper-based water purification material. The activated carbon fiber paper-based water purification material is processed into a wavy structure, then wound into a cylindrical shape, and the edges are glued together to form a filter element.

[0035] Comparative Example 1

[0036] Pre-treating polyacrylonitrile (PA) chopped fibers with a 20% sodium hydroxide solution for 24 hours; dispersing PA fibers in water to form a 20% suspension; grinding the fibers in a disc mill (the disc mill system consists of three double-disc mills connected in series, with the gap between the first mill 0.5mm, the second 0.3mm, and the third 0.15mm adjusted to fibrillate the chopped fibers while maintaining the length of the pulp fibers, forming pulp; dewatering and storing the pulp. Using a trough pulper, 10% by weight of the prepared pulp is mixed with 20% PA-based activated carbon fiber, 20% bicomponent PET fiber, 30% coconut shell activated carbon granules, and 20% alumina granules. Water is added to the mixture to form a 10% suspension. The suspension is pumped to a pulp tower and then through a batching tank, where the suspension delivery ratio is adjusted according to different process requirements. Finally, it is pumped to a forming device for forming, followed by dewatering, drying, and cooling to obtain activated carbon fiber paper-based water purification material. The activated carbon fiber paper-based water purification material is processed into a wavy structure, then wound into a cylindrical shape, and the edges are glued together to form a filter element.

[0037] Comparative Example 2

[0038] Pre-treating polyacrylonitrile (PA) chopped fibers with a 20% sodium hydroxide solution for 24 hours; dispersing PA fibers in water to form a 20% suspension; grinding the fibers in a disc mill (the disc mill system consists of three double-disc mills connected in series, with the gap between the first mill 0.5mm, the second 0.3mm, and the third 0.15mm) to fibrillate the chopped fibers while maintaining the length of the pulp fibers, thus forming pulp; dewatering and storing the pulp. Using a trough pulper, 10% by weight of the prepared pulp is mixed with 20% PA-based activated carbon fiber, 30% bicomponent PET fiber, 25% coconut shell activated carbon granules, and 15% alumina granules. Water is added to the mixture to form a 10% suspension. The suspension is pumped to a pulp tower and then through a batching tank, where the suspension delivery ratio is adjusted according to different process requirements. Finally, it is pumped to a forming device for forming. After forming, dewatering, drying, and cooling yields activated carbon fiber paper-based water purification material. The activated carbon fiber paper-based water purification material is processed into a wavy structure, then wound into a cylindrical shape, and the edges are glued together to form a filter element.

[0039] Comparative Example 3

[0040] Pre-treating polyacrylonitrile (PA) chopped fibers with a 20% sodium hydroxide solution for 24 hours; dispersing PA fibers in water to form a 20% suspension; grinding the fibers in a disc mill (the disc mill system consists of three double-disc mills connected in series, with the gap between the first mill 0.5mm, the second 0.3mm, and the third 0.15mm) to fibrillate the chopped fibers while maintaining the length of the pulp fibers, forming pulp; dewatering and storing the pulp. Using a trough pulper, 10% by weight of the prepared pulp is mixed with 20% PA-based activated carbon fiber, 25% bicomponent PET fiber, 25% coconut shell activated carbon granules, and 20% alumina granules. Water is added to the mixture to form a 10% suspension. The suspension is pumped to a pulp tower and then through a batching tank, where the suspension delivery ratio is adjusted according to different process requirements. Finally, it is pumped to a forming device for forming. After forming, dewatering, drying, and cooling yields activated carbon fiber paper-based water purification material. The activated carbon fiber paper-based water purification material is processed into a wavy structure, then wound into a cylindrical shape, and the edges are glued together to form a filter element.

[0041] Comparative Example 4

[0042] Pre-treating polyacrylonitrile (PA) chopped fibers with a 20% sodium hydroxide solution for 24 hours; dispersing PA fibers in water to form a 20% suspension; grinding the fibers in a disc mill (the disc mill system consists of three double-disc mills connected in series, with the gap between the first mill 0.5mm, the second 0.3mm, and the third 0.15mm) to fibrillate the chopped fibers while maintaining the length of the pulp fibers, forming pulp; dewatering and storing the pulp. Using a trough pulper, 10% by weight of the prepared pulp is mixed with 20% PA-based activated carbon fiber, 25% bicomponent PET fiber, 30% coconut shell activated carbon granules, and 15% alumina granules. Water is added to the mixture to form a 10% suspension. The suspension is pumped to a pulp tower and then through a batching tank, where the suspension delivery ratio is adjusted according to different process requirements. Finally, it is pumped to a forming device for forming. After forming, dewatering, drying, and cooling yields activated carbon fiber paper-based water purification material. The activated carbon fiber paper-based water purification material is processed into a wavy structure, then wound into a cylindrical shape, and the edges are glued together to form a filter element.

[0043] Comparative Example 5

[0044] Pre-treating polyacrylonitrile (PA) chopped fibers with a 20% sodium hydroxide solution for 24 hours; dispersing PA fibers in water to form a 20% suspension; grinding the fibers in a disc mill (the disc mill system consists of three double-disc mills connected in series, with the gap between the first mill 0.5mm, the second 0.3mm, and the third 0.15mm) to fibrillate the chopped fibers while maintaining the length of the pulp fibers, forming pulp; dewatering and storing the pulp. Using a trough pulper, 10% by weight of the prepared pulp is mixed with 20% PA-based activated carbon fiber, 30% bicomponent PET fiber, 20% coconut shell activated carbon granules, and 20% alumina granules. Water is added to the mixture to form a 10% suspension. The suspension is pumped to a pulp tower and then through a batching tank, where the suspension delivery ratio is adjusted according to different process requirements. Finally, it is pumped to a forming device for forming. After forming, dewatering, drying, and cooling yields activated carbon fiber paper-based water purification material. The activated carbon fiber paper-based water purification material is processed into a wavy structure, then wound into a cylindrical shape, and the edges are glued together to form a filter element.

[0045] The difference between Comparative Example 1 and Example 1 lies in the different amounts of bicomponent PET fiber and aluminum oxide particles added.

[0046] The difference between Comparative Example 2 and Example 1 is that the content of coconut shell activated carbon particles and aluminum oxide particles is different.

[0047] The difference between Comparative Example 3 and Example 1 lies in the different contents of coconut shell activated carbon particles, bicomponent PET fiber, and alumina particles.

[0048] The difference between Comparative Example 4 and Example 1 is that the content of bicomponent PET fiber and aluminum oxide particles is different.

[0049] The difference between Comparative Example 5 and Example 1 lies in the different contents of coconut shell activated carbon particles, bicomponent PET fibers, and alumina particles.

[0050] Performance testing

[0051] The water used for the test was tap water, 100 ml in quantity, and its free chlorine content, color, and bacterial count were measured. The activated carbon paper-based fiber material obtained in the above examples was used as a filter element to filter the tap water, and the flux was measured. The filtered water sample was then tested for free chlorine content, decolorization, and sterilization.

[0052] Flow rate test: Connect the activated carbon paper-based water purification material filter cartridge, flow meter, pressure gauge and 3-point pipe to ensure no leakage; adjust the water source to stabilize the working pressure at 0.1MPa, and record the flow meter reading after the water flow stabilizes; keep the pressure stable, and continuously observe and record the flow rate for at least 5 minutes to ensure data stability.

[0053] Free chlorine test: The free chlorine concentration was determined by the N,N-diethyl-p-phenylenediamine (DPD) spectrophotometric method according to GB / T 5750.11-2023 "Standard Examination Methods for Drinking Water - Part 11: Disinfectant Indicators". The free chlorine adsorption value was calculated by the following formula:

[0054]

[0055] Where: Q: free chlorine adsorption value (mg / g), c0: initial free chlorine concentration (mg / L), c1: free chlorine concentration after adsorption (mg / L), V: solution volume (L), m: adsorbent mass (g).

[0056] Decolorization test: The caramel decolorization rate of activated carbon fiber paper-based water purification materials was determined in accordance with GB / T 12496.9-2015 "Test Methods for Wood-based Activated Carbon: Determination of Caramel Decolorization Rate".

[0057] Sterilization test: Escherichia coli strains were cultured on solid medium in a sterile incubator at 37°C for 24 h. Single colonies activated by the culture were cultured on a shaker at 37°C with liquid LB at a shaking speed of 200 rpm for 24 h. The obtained bacterial suspension was transferred to a 10 mL sterile centrifuge tube and centrifuged at 8000 rpm for 10 min. The supernatant was removed, and the bacterial suspension was diluted with PBS buffer to a concentration of approximately 3 × 10⁴ CFU / mL. HFPAN-TiO₂ pulp was made into filter paper with a basis weight of 50 g / m². The bacterial suspension was then filtered using the filter paper. Control experiments were conducted under the following three conditions: (1) filtration using only HFPAN-TiO₂ filter paper; (2) ordinary filter paper + UV lamp; (3) HFPAN-TiO₂ filter paper + UV lamp. Furthermore, in (2) and (3), the filter was first irradiated with ultraviolet light for half an hour before filtration. Then, 1 mL of the filtered filtrate was evenly spread on a solid culture medium and cultured in a sterile incubator at 37°C for 24 hours. The bacterial concentration was calculated by plate counting method.

[0058] flux Free chlorine Decolorization (color after filtration) Sterilization rate Example 1 700G 0.002 2 99.9％ Comparative Example 1 530G 0.005 5 98.5％ Comparative Example 2 490G 0.005 6 99.4％ Comparative Example 3 550G 0.005 3 99.0％ Comparative Example 4 520G 0.005 4 98.9％ Comparative Example 5 485G 0.005 3 99.5％ Comparative Example 6 512G 0.005 6 98.7％

Claims

1. A method for preparing an activated carbon fiber paper-based water purification material, characterized in that, The preparation method includes: a. Pulping: Polyacrylonitrile short-cut fibers are pretreated with a surface treatment agent, dispersed, and ground to obtain pulp. The surface treatment agent is a 10%-30% (w / w) sodium hydroxide aqueous solution. The pretreatment time is 12-24 hours. The pretreated polyacrylonitrile short-cut fibers are rinsed with water until neutral. The polyacrylonitrile short-cut fibers are dispersed in water to form a 5-20% (w / w) suspension. The fiber length of the pulp is 1.5-3 mm, the aspect ratio is 100-150:1, and the surface of the pulp has microfibers. The Shore freeness of the pulp is 25-51°SR, the Canadian freeness is 180-680 mL, and the specific surface area is 25-50 m². 2 / g; b. Mixing: Use a trough pulper to mix pulp, polyacrylonitrile-based activated carbon fiber, bicomponent PET fiber, activated carbon granules and alumina granules. After mixing, add water to the raw materials to obtain a suspension. c. Papermaking: The suspension is pumped to a pulp tower, then the proportions are adjusted in a batching tank, and finally pumped to a forming machine for forming. After forming, the paper is dehydrated, dried, and cooled to obtain activated carbon fiber paper-based water purification material. The forming machine is an inclined wire paper machine or a cylinder paper machine with a speed of 50-100 m / min, and the basis weight of the formed paper is 60-250 g / m². 2 The drying temperature is 120-140℃. d. Post-processing: The activated carbon fiber paper-based water purification material is processed into a wavy structure, then wound into a cylindrical shape, and the edges are glued together to form a filter element; The raw materials, by weight percentage, include 5%-25% polyacrylonitrile-based activated carbon fiber, 10%-30% activated carbon granules, 15-30% bicomponent PET fiber, and 5-20% alumina granules.

2. The preparation method of the activated carbon fiber paper-based water purification material according to claim 1, characterized in that... The activated carbon particles are one or more of coconut shell activated carbon, fruit shell activated carbon, and coal-based activated carbon.

3. The preparation method of the activated carbon fiber paper-based water purification material according to claim 1, characterized in that, The polyacrylonitrile-based activated carbon fiber has a diameter of 5-20 μm and a length of 2-5 mm.

4. The preparation method of the activated carbon fiber paper-based water purification material according to claim 1, characterized in that, The activated carbon particles have a mesh size of 300-800 mesh.

5. The preparation method of the activated carbon fiber paper-based water purification material according to claim 1, characterized in that, The fineness of the bicomponent PET fiber is 1.5-3D, and the length is 3-5mm.

6. The preparation method of the activated carbon fiber paper-based water purification material according to claim 1, characterized in that, The alumina particles have a particle size of 2-5 micrometers.

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