Preparation method of cellulose-based heterogeneous cation exchange membrane with high strength and high stability

Abstract

The invention discloses a cellulose-based heterogeneous cation exchange membrane with high strength and high stability and a preparation method thereof. The preparation method comprises the following steps: mixing pretreated ion exchange resin Amberlyst 15 (H) with a PVDF (Polyvinylidene Fluoride) solution, adding SDS (Sodium Dodecyl Sulfate) to assist dispersion to obtain a mixed solution, taking cellulose filter paper as a membrane framework base material, and coating the mixed solution on the cellulose filter paper to prepare the cellulose-based heterogeneous cation exchange membrane. Surface morphology, structure characterization and physical and electrochemical characterization are carried out on the heterogeneous cation exchange membrane, and the cellulose-based heterogeneous cation exchange membrane is optimized by regulating and controlling the concentration of PVDF and ion exchange resin. The heterogeneous cation exchange membrane prepared by the method has the characteristics of high strength and high stability, and valuable basic data and theoretical guidance are provided for the heterogeneous cation exchange membrane.

Description

Technical Field

[0001] The present invention belongs to the technical field of heterogeneous ion exchange membranes, and relates to a method for preparing a cellulose-based heterogeneous cation exchange membrane with high strength and high stability. Background Art

[0002] Ion exchange membrane (IEM) is a polymer functional membrane with ion selective permeability. It originated from ion exchange resin and can be considered as a membrane-like product of ion exchange resin. It mainly allows ions of specific charge (such as cations or anions) to selectively pass through through the charged groups fixed on the surface (such as sulfonic acid groups or quaternary ammonium groups), while blocking ions of opposite charge or neutral molecules. Its working principle is based on electric field drive and Donnan exclusion effect, and it uses the electrostatic barrier formed by the charged groups in the membrane to achieve ion separation. After more than a hundred years of development and technological iteration, ion exchange membranes have now been successfully prepared from the laboratory and applied in various industries. They have received great attention in fields such as seawater desalination, environmental protection, chemical synthesis, food processing, etc., and have gained an indispensable position. At the same time, with the world's high attention to environmental governance and energy fields, it can be foreseen that ion exchange membranes will play an increasingly important role in these fields.

[0003] Ion exchange membranes are essentially ion exchange resins in membrane form. They are polymer polyelectrolyte materials with active exchange groups. A typical ion exchange membrane generally consists of three basic components: a network-like polymer backbone, fixed active groups, and mobile ions attached to these groups. The backbone, constructed from a three-dimensional cross-linked network of polymers, provides mechanical strength. Charge interactions between the fixed active groups and mobile ions repel like-charged ions and selectively transmit oppositely charged ions. This permselective property forms the theoretical basis of electro-membrane separation technology. This membrane material selectively transmits ions of specific charge through the electrostatic field effect created by the fixed charged groups, and is therefore often referred to as a permselective membrane in engineering applications. For example, in seawater desalination, ion exchange membranes achieve desalination and brackish water desalination through electrodialysis, achieving desalination rates exceeding 90% and reducing energy consumption by 30%-50% compared to traditional reverse osmosis. Furthermore, diffusion dialysis processes are used to recover resources such as sulfuric acid and hydrochloric acid from steel pickling wastewater, achieving recovery rates exceeding 85%, significantly reducing processing costs. In addition, it is also used in industries such as sewage treatment, ultrapure water preparation and heavy metal recovery.

[0004] In the traditional preparation of heterogeneous ion exchange membranes, ion exchange resins and binders are physically and mechanically mixed or hot-pressed to form a multiphase structure. However, due to the large difference in polarity and poor interfacial compatibility between the resin particles and the binder matrix, problems such as agglomeration and stratification are prone to occur, resulting in generally low mechanical strength of the membrane (tensile strength is mostly less than 10 MPa), and it is easy to rupture due to stress concentration in acidic and alkaline environments or during long-term operation. To improve strength, the industry often introduces reinforcing substrates such as glass fiber cloth and polyester mesh. However, these substrates have inherent defects: Weak interfacial bonding: Non-polar or low-polar substrates such as glass fiber and polyester lack intermolecular forces (such as hydrogen bonding and polar adsorption) with polar resins (such as Amberlyst 15) and binders (such as PVDF). Relying solely on physical intercalation, this easily leads to the formation of gaps between the substrate and the membrane matrix. This not only increases ion conduction resistance (membrane resistance increases by ≥20%) but also becomes a weak point for swelling and permeation, reducing the membrane's swelling resistance (swelling rate ≥30% in 1 mol / L NaCl). Achieving a performance balance is difficult: While rigid substrates (such as glass fiber) improve strength, they significantly reduce membrane flexibility (elongation at break ≤5%) and can easily become brittle during processing. Flexible polyester substrates, while more flexible, suffer from insufficient chemical resistance and are prone to degradation under long-term acidic conditions (strength retention ≤70% after immersion in 1 mol / L HCl for 30 days).

[0005] Based on this, the present invention proposes a new heterogeneous ion exchange membrane, which can overcome the above-mentioned defects and has the characteristics of high strength and high stability. Summary of the Invention

[0006] The present invention aims to address the relatively low strength of heterogeneous ion exchange membranes by providing a high-strength, high-stability cellulose-based heterogeneous cation exchange membrane and a method for preparing the membrane. This method can provide valuable basic data and theoretical guidance for future research on heterogeneous ion exchange membranes.

[0007] The technical solution adopted in the present invention is as follows:

[0008] A method for preparing a cellulose-based heterogeneous cation exchange membrane with high strength and high stability comprises mixing a pretreated ion exchange resin Amberlyst 15(H) and a PVDF solution, adding SDS (sodium dodecyl sulfate) to assist in dispersion to obtain a mixed solution, coating the mixed solution on a cellulose filter paper using a cellulose filter paper as a membrane skeleton substrate, and drying to prepare a cellulose-based heterogeneous cation exchange membrane with high strength and high stability.

[0009] In the above technical solution, the ion exchange resin (IER) is further pretreated to control its particle size to ≤50 μm. Generally, the resin is dried in an oven at 60°C for 24 hours, ground into powder multiple times by a knife-type powder grinder, and then vibrated and sieved with a sieve to obtain resin powder below 50 μm (300 mesh). More preferably, the average particle size is 3.7 μm.

[0010] Furthermore, the cellulose filter paper was cut into a desired size and then dried in an oven at 60° C. for 24 h before use.

[0011] Furthermore, the pretreated ion exchange resin, PVDF, and SDS were placed in a DMAC solvent to prepare a mixed solution, which was stirred for more than 24 hours using a digital temperature-controlled stirrer at 60° C., and then ultrasonically dispersed for at least 1 hour using a digitally controlled ultrasonic cleaner.

[0012] Furthermore, the mass contents of the pretreated ion exchange resin, PVDF, and SDS are 1-3%, 8-12%, and 2%, respectively.

[0013] Furthermore, a cellulose filter paper is placed on a glass plate, the prepared mixed solution is poured onto the filter paper, and then a glass rod is used to press the mixed solution evenly and forcefully to coat the filter paper. The coated filter paper is then placed in an oven and dried at 60°C for 12 hours to finally obtain a cellulose-based heterogeneous cationic ion exchange membrane.

[0014] Furthermore, the surface morphology, structure, physical and electrochemical characterizations of membranes with different proportions were carried out, and the results were analyzed and studied.

[0015] The high-strength and high-stability cellulose-based heterogeneous cation exchange membrane of the present invention provides a solution to the low-strength problem of heterogeneous ion exchange membranes and provides valuable basic data and theoretical guidance for subsequent research on heterogeneous ion exchange membranes.

[0016] The beneficial effects of the present invention are:

[0017] The present invention uses cellulose filter paper as a substrate, combined with ion exchange resin (Amberlyst 15) pretreatment, SDS-assisted dispersion, and specific process parameter control to prepare a cellulose-based heterogeneous cation exchange membrane. The cellulose filter paper's lignocellulose backbone is rich in hydroxyl groups, which form hydrogen bonds and polar interactions with the sulfonic acid groups of the ion exchange resin and the polar segments of polyvinylidene fluoride (PVDF), effectively eliminating interfacial voids and achieving a close molecular-level bond between the substrate and the membrane matrix. The cellulose filter paper's natural reticular structure combines both rigidity and flexibility. Combined with the bonding effect of PVDF, the membrane achieves a tensile strength of 25-35 MPa (significantly higher than the ≤10 MPa of conventional heterogeneous membranes) and reduces ion conduction resistance (membrane resistance is ≥15% lower than that of glass fiber substrates). The resulting membrane also exhibits excellent fatigue resistance, with an elongation at break ≥15%, addressing the membrane embrittlement problem associated with conventional rigid substrates (such as glass fiber). Through ion exchange resin pretreatment (controlling particle size ≤50μm), SDS-assisted dispersion (inhibiting agglomeration), and the interfacial anchoring effect of the cellulose substrate, the membrane maintains stability above 94% after immersion in a H2O2 solution containing Fe3+ for three days, and this stability can be increased to 96.71% with optimized PVDF to resin ratio. The cellulose substrate itself is resistant to acid and alkali corrosion (strength retention ≥90% after immersion in 1mol / L HCl for 30 days), and combined with the hydrophobicity of PVDF, the membrane's swelling rate in a 1mol / L NaCl solution can be controlled to ≤20% (much lower than the ≥30% of conventional substrate membranes). Furthermore, by optimizing the resin to PVDF ratio, resin "de-powdering" or excessive swelling can be avoided, extending the membrane's service life. The method of the present invention solves the contradiction of "increased strength and decreased stability" of traditional substrate heterogeneous ion membranes; the process adaptability is high: the surface of cellulose filter paper is porous and moderately hydrophilic, and uniform penetration and adhesion of the resin-binder solution can be achieved through a simple coating process, avoiding the uneven coating problem caused by the smooth surface of traditional substrates and reducing the difficulty of preparation; the prepared membrane has significant practical value and industrial prospects in the fields of seawater desalination, acid and alkali recovery, sewage treatment, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 FE-SEM of cellulose-based ion exchange membranes, (a) PVDF 10wt%, 1wt% IER, (b) PVDF 10wt%, 2wt% IER, (c) PVDF 10wt%, 3wt% IER, (d) PVDF 8wt%, 3wt% IER, (e) 10wt%, 3wt% IER, (f) 12wt%, 3wt% IER.

[0019] Figure 2 Fourier transform infrared spectra of PVDF, Amberlyst 15(H), cellulose filter paper and cellulose-based heterogeneous cation exchange membrane.

[0020] Figure 3 (a) Changes in the moisture content of cellulose-based ion exchange membranes; (b) Water contact angles of cellulose-based ion exchange membranes and their images.

[0021] Figure 4 (a) ion exchange capacity of cellulose-based ion exchange membrane; (b) fixed ion concentration of cellulose-based ion exchange membrane.

[0022] Figure 5 (a) Transmission number of cellulose-based cation exchange membrane; (b) Selectivity of cellulose-based cation exchange membrane.

[0023] Figure 6 (a) Average thickness of cellulose-based ion exchange membrane; (b) Stress-strain curve of PVDF 8wt%; (c) Stress-strain curve of PVDF 10wt%; (d) Stress-strain curve of PVDF 12wt%.

[0024] Figure 7 Oxidative stability of cellulose-based ion exchange membranes. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. The resin used in the embodiments of the present invention is Amberlyst 15 (H).

[0026] Example 1

[0027] The resin was dried in a 60°C oven for 24 hours, ground multiple times with a blade-type powder grinder into a powder, and then vibrated and sieved to remove resin powder with a particle size of less than 50 μm (300 mesh) (average particle size 3.7 μm). Cellulose filter paper was cut into 15 cm × 15 cm squares and then dried in an oven at 60°C for 24 hours before use. Powdered ion exchange resin (IER) was prepared with PVDF and SDS in a DMAC solvent to form a composite solution. The mixed solution was stirred for at least 24 hours at 60°C using a digital temperature-controlled stirrer and then ultrasonically dispersed for 1 hour using a digitally controlled ultrasonic cleaner. The ratio of PVDF to IER was 8 wt% and 1 wt%. The mixed solution was then evenly coated onto the filter paper using a glass rod and pressed firmly. The coated filter paper was then placed in an oven and dried at 60°C for 12 hours, ultimately yielding the cellulose-based heterogeneous cation exchange membrane M1.

[0028] Example 2

[0029] The resin was dried in a 60°C oven for 24 hours, ground multiple times with a blade-type powder grinder into a powder, and then vibrated and sieved to remove resin powder with a particle size of less than 50 μm (300 mesh) (average particle size 3.7 μm). Cellulose filter paper was cut into 15 cm × 15 cm squares and then dried in an oven at 60°C for 24 hours before use. Powdered ion exchange resin (IER) was prepared with PVDF and SDS in a DMAC solvent to form a composite solution. The mixed solution was stirred for at least 24 hours at 60°C using a digital temperature-controlled stirrer and then ultrasonically dispersed for 1 hour using a digitally controlled ultrasonic cleaner. The ratio of PVDF to IER was 8 wt% and 2 wt%. The mixed solution was then evenly coated onto the filter paper using a glass rod and applied with force. The coated filter paper was then placed in an oven and dried at 60°C for 12 hours, yielding the cellulose-based heterogeneous cation exchange membrane M2.

[0030] Example 3

[0031] The resin was dried in a 60°C oven for 24 hours, ground into powder multiple times using a blade-type powder grinder, and then vibrated and sieved to remove resin powder with a particle size of less than 50 μm (300 mesh) (average particle size 3.7 μm). Cellulose filter paper was cut into 15 cm × 15 cm squares and then dried in an oven at 60°C for 24 hours before use. Powdered ion exchange resin (IER) was prepared in a DMAC solvent along with PVDF and SDS to form a composite solution. The mixed solution was stirred for at least 24 hours at 60°C using a digital temperature-controlled stirrer and then ultrasonically dispersed for 1 hour using a digitally controlled ultrasonic cleaner. The ratio of PVDF to IER was 8 wt% and 3 wt%. The mixed solution was then evenly coated onto the filter paper using a glass rod and applied with force. The coated filter paper was then placed in an oven and dried at 60°C for 12 hours, yielding the cellulose-based heterogeneous cation exchange membrane M3.

[0032] Example 4

[0033] The resin was dried in a 60°C oven for 24 hours, ground multiple times with a blade-type powder grinder into a powder, and then vibrated and sieved to remove resin powder with a particle size of less than 50 μm (300 mesh) (average particle size 3.7 μm). Cellulose filter paper was cut into 15 cm × 15 cm squares and then dried in an oven at 60°C for 24 hours before use. Powdered ion exchange resin (IER) was prepared with PVDF and SDS in a DMAC solvent to form a composite solution. The mixed solution was stirred for at least 24 hours at 60°C using a digital temperature-controlled stirrer and then ultrasonically dispersed for 1 hour using a digitally controlled ultrasonic cleaner. The ratio of PVDF to IER was 10 wt% (1 wt%). The mixed solution was then evenly coated onto the filter paper using a glass rod and pressed firmly. The coated filter paper was then placed in an oven and dried at 60°C for 12 hours, yielding the cellulose-based heterogeneous cation exchange membrane M4.

[0034] Example 5

[0035] The resin was dried in a 60°C oven for 24 hours, ground multiple times with a blade-type powder grinder into a powder, and then vibrated and sieved to remove resin powder with a particle size of less than 50 μm (300 mesh) (average particle size 3.7 μm). Cellulose filter paper was cut into 15 cm × 15 cm squares and then dried in an oven at 60°C for 24 hours before use. Powdered ion exchange resin (IER) was prepared with PVDF and SDS in a DMAC solvent to form a composite solution. The mixed solution was stirred for at least 24 hours at 60°C using a digital temperature-controlled stirrer and then ultrasonically dispersed for 1 hour using a digitally controlled ultrasonic cleaner. The ratio of PVDF to IER was 10 wt% and 2 wt%. The mixed solution was then evenly coated onto the filter paper using a glass rod and pressed firmly. The coated filter paper was then placed in an oven and dried at 60°C for 12 hours, resulting in the cellulose-based heterogeneous cation exchange membrane M5.

[0036] Example 6

[0037] The resin was dried in a 60°C oven for 24 hours, ground multiple times with a blade-type powder grinder into a powder, and then vibrated and sieved to remove resin powder with a particle size of less than 50 μm (300 mesh) (average particle size 3.7 μm). Cellulose filter paper was cut into 15 cm × 15 cm squares and then dried in an oven at 60°C for 24 hours before use. Powdered ion exchange resin (IER) was prepared with PVDF and SDS in a DMAC solvent to form a composite solution. The mixed solution was stirred for at least 24 hours at 60°C using a digital temperature-controlled stirrer and then ultrasonically dispersed for 1 hour using a digitally controlled ultrasonic cleaner. The ratio of PVDF to IER was 10 wt% and 3 wt%. The mixed solution was then evenly coated onto the filter paper using a glass rod and applied with force. The coated filter paper was then placed in an oven and dried at 60°C for 12 hours, resulting in the cellulose-based heterogeneous cation exchange membrane M6.

[0038] Example 7

[0039] The resin was dried in a 60°C oven for 24 hours, ground multiple times with a blade-type powder grinder into a powder, and then vibrated and sieved to remove resin powder with a particle size of less than 50 μm (300 mesh) (average particle size 3.7 μm). Cellulose filter paper was cut into 15 cm × 15 cm squares and then dried in an oven at 60°C for 24 hours before use. Powdered ion exchange resin (IER) was prepared with PVDF and SDS in a DMAC solvent to form a composite solution. The mixed solution was stirred for at least 24 hours at 60°C using a digital temperature-controlled stirrer and then ultrasonically dispersed for 1 hour using a digitally controlled ultrasonic cleaner. The ratio of PVDF to IER was 12 wt %. The mixed solution was then evenly coated onto the filter paper using a glass rod and applied with force. The coated filter paper was then placed in an oven and dried at 60°C for 12 hours, resulting in the cellulose-based heterogeneous cation exchange membrane M7.

[0040] Example 8

[0041] The resin was dried in a 60°C oven for 24 hours, ground multiple times with a blade-type powder grinder into a powder, and then vibrated and sieved to remove resin powder with a particle size of less than 50 μm (300 mesh) (average particle size 3.7 μm). Cellulose filter paper was cut into 15 cm × 15 cm squares and then dried in an oven at 60°C for 24 hours before use. Powdered ion exchange resin (IER) was prepared with PVDF and SDS in a DMAC solvent to form a composite solution. The mixed solution was stirred for at least 24 hours at 60°C using a digital temperature-controlled stirrer and then ultrasonically dispersed for 1 hour using a digitally controlled ultrasonic cleaner. The ratio of PVDF to IER was 12 wt% and 2 wt%. The mixed solution was then evenly coated onto the filter paper using a glass rod and applied with force. The coated filter paper was then placed in an oven and dried at 60°C for 12 hours, resulting in the cellulose-based heterogeneous cation exchange membrane M8.

[0042] Example 9

[0043] The resin was dried in a 60°C oven for 24 hours, ground multiple times with a blade-type powder grinder into a powder, and then vibrated and sieved to remove resin powder with a particle size of less than 50 μm (300 mesh) (average particle size 3.7 μm). Cellulose filter paper was cut into 15 cm × 15 cm squares and then dried in an oven at 60°C for 24 hours before use. Powdered ion exchange resin (IER) was prepared with PVDF and SDS in a DMAC solvent to form a composite solution. The mixed solution was stirred for at least 24 hours at 60°C using a digital temperature-controlled stirrer and then ultrasonically dispersed for 1 hour using a digitally controlled ultrasonic cleaner. The ratio of PVDF to IER was 12 wt% and 3 wt%. The mixed solution was then evenly coated onto the filter paper using a glass rod and applied with force. The coated filter paper was then placed in an oven and dried at 60°C for 12 hours, resulting in the cellulose-based heterogeneous cation exchange membrane M9.

[0044] The electron microscope image and fiber diameter distribution of the prepared nanofibers are as follows Figure 1 shown.

[0045] Figure 2 It can be seen that compared with -SO3 on ion exchange resin - The characteristic peaks are mainly at 1060, 1014, 806, and 653 cm -1 The infrared peaks of the sulfonic acid groups in the cellulose-based ion exchange membrane mainly appear at 1072, 879, 831, and 632 cm -1 The peak shifted slightly due to the cross-linking reaction, indicating that the ion exchange resin has been successfully cross-linked and loaded on the cellulose substrate. In addition, we found the characteristic peak of PVDF on the cellulose ion exchange membrane, and its main peak range appeared in 1500-1100 cm -1 Specifically, it is 1402cm -1 The rocking vibration peak of CH2 and 1174 cm -1 The -CF2 symmetric stretching peak at 37° indicated that PVDF as a binder had also been cross-linked on the cellulose substrate.

[0046] Figure 3 (a) shows that the moisture content of cellulose heterogeneous cation exchange membrane is related to the size and number of water-locking voids in the membrane. When the PVDF ratio is the same, the increase in the resin ratio will reduce the moisture content due to filling the voids; when the resin addition amount is the same, the increase in the PVDF ratio will also cause the moisture content to decrease due to filling the voids. Moreover, PVDF is better than resin in reducing the moisture content because it is dissolved and coated into a film. Therefore, the moisture content is mainly affected by the degree of cross-linking of the cellulose substrate by the ion exchange resin and PVDF. The higher the degree of cross-linking, the lower the moisture content. The moisture content needs to be controlled within an appropriate range. If it is too low, it is easy to pollute and shorten the lifespan. If it is too high, the structure will be unstable, easy to swell and deform, and the resin and binder will be unevenly bonded. Figure 3 (b) shows that the cellulose substrate is hydrophobic due to its low surface energy, and the water contact angle is greater than 90°. At the same PVDF content, an increase in resin content will reduce the water contact angle and improve the hydrophilicity due to the increase in the number of sulfonic acid groups on the membrane surface (sulfonic acid groups are highly polar and can form hydrogen bonds with water molecules); at the same resin addition amount, an increase in PVDF content will increase the water contact angle due to the hydrophobicity of the material itself, but the increase is limited. The hydrophilicity of the membrane is mainly determined by the resin loading. However, too high a resin content will lead to problems such as decreased loading stability, easy powdering and swelling, and the resin content needs to be adjusted to optimize performance.

[0047] Figure 4 (a) shows that the ion exchange capacity (IEC) of cellulose-based heterogeneous cation exchange membranes is an inherent property of the resin in the membrane, reflecting the total number of chemical groups available for reaction per unit mass of membrane. At the same PVDF content, increasing the resin content improves the IEC due to the increased number of sulfonic acid groups. However, excessive resin content can lead to poor solution dispersibility and resin shedding. At the same resin loading, increasing the PVDF content as a binder can enhance resin loading stability, reduce shedding, and thus improve the IEC. Figure 4 The fixed ion concentration in (b) reflects the number of chemical groups per unit volume of the membrane and is affected by both IEC and water content. Since the water content is less than 100%, its variation pattern is consistent with IEC (different from the inverse relationship of electrospun membranes). A high fixed ion concentration helps optimize ion channels and enhance membrane selectivity.

[0048] Figure 5 It shows that the transmission numbers of the membranes are all above 60%, and increase with the increase of PVDF and IER content.

[0049] Figure 6 It shows that at the same PVDF content (such as M1, M2, M3), the stress of the membrane decreases as the resin content decreases.

[0050] Figure 7 It can be seen that the cellulose-based ion exchange membrane contains Fe 3+ The stability of the composites after immersion in H2O2 solution for three days was above 94%, and the stability increased from 94.31% to 96.71% with the increase of PVDF and IER content.

Claims

1. A method for preparing a cellulose-based heterogeneous cation exchange membrane with high strength and high stability, characterized in that: The pretreated ion exchange resin Amberlyst 15(H) and PVDF solution were mixed, and SDS was added to assist dispersion to obtain a mixed solution. The solution was coated on cellulose filter paper using cellulose filter paper as the membrane skeleton substrate and dried to obtain a cellulose-based heterogeneous cation exchange membrane with high strength and high stability.

2. The method for preparing a cellulose-based heterogeneous cation exchange membrane with high strength and high stability according to claim 1, characterized in that: The ion exchange resin (IER) is pretreated to reduce the particle size and improve the dispersibility, and the IER particle size is controlled to be ≤50 μm.

3. The method for preparing a cellulose-based heterogeneous cation exchange membrane with high strength and high stability according to claim 2, characterized in that: The pretreatment is specifically as follows: drying the IER in an oven at 60° C. for 24 hours, grinding it into powder multiple times using a knife-head powder grinder, and then vibrating and sieving the resin powder below 50 μm (300 mesh) using a sieve.

4. The method for preparing a cellulose-based heterogeneous cation exchange membrane with high strength and high stability according to claim 1, characterized in that: The cellulose filter paper was cut into the required size and placed in an oven to dry at 60°C for 24 h before use.

5. The method for preparing a cellulose-based heterogeneous cation exchange membrane with high strength and high stability according to claim 1, characterized in that: The IER, PVDF and SDS were placed in a DMAC solvent to prepare a mixed solution, and the mixed solution was stirred at 60° C. for more than 24 hours, and then ultrasonically dispersed for at least 1 hour.

6. The method for preparing a cellulose-based heterogeneous cation exchange membrane with high strength and high stability according to claim 5, characterized in that: The mass concentrations of IER, PVDF and SDS in the mixed solution are 1-3%, 8-12% and 2% respectively.

7. The method for preparing a cellulose-based heterogeneous cation exchange membrane with high strength and high stability according to claim 1, characterized in that: Place a cellulose filter paper on a glass plate, pour the prepared mixed solution onto the filter paper, and then use a glass rod to press evenly and forcefully to coat the mixed solution on the filter paper. Then place the coated filter paper in an oven and dry it at 60°C for 12 hours to finally obtain a cellulose-based heterogeneous cationic ion exchange membrane with high strength and high stability.

8. A cellulose-based heterogeneous cation exchange membrane with high strength and high stability, characterized in that: The film is prepared by the method according to any one of claims 1 to 7, and has a tensile strength of 25-35 MPa, an elongation at break of ≥15%, and is resistant to acid and alkali corrosion.

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