Preparation method of fly ash-cellulose composite cat litter

Abstract

The present application belongs to the technical field of industrial solid waste recycling, and particularly relates to a preparation method of fly ash-cellulose composite cat litter. First, cellulose is dissolved in a low-temperature alkali solution to make cellulose exist in a liquid phase, then allyl glycidyl ether is added under nitrogen protection, the hydroxyl group on the cellulose attacks the epoxy group to form an ether bond to obtain allyl cellulose, and then the pure allyl cellulose is obtained by washing and dialysis purification with acetone. Then, the fly ash and the allyl cellulose are mixed in a certain proportion, N,N'-methylene bisacrylamide is used as a crosslinking agent, potassium persulfate is used as an initiator to initiate copolymerization, and after granulation, a new fly ash-cellulose composite cat litter is obtained. The technology not only realizes the resource utilization of fly ash, but also has the advantages of biodegradability, renewability, good biocompatibility and the like, overcomes the shortcomings of traditional cellulose cat litter in terms of odor absorption and clumping, and meets the value orientation of green chemistry.

Description

Technical Field

[0001] This invention belongs to the field of industrial solid waste recycling technology, specifically relating to a method for preparing fly ash-cellulose composite cat litter. Background Technology

[0002] Currently, commercially available cat litter is mainly categorized into several types based on its raw materials and properties, including bentonite cat litter, tofu cat litter, silica gel cat litter, pine cat litter, and cellulose cat litter. Against the backdrop of a booming pet economy and the increasing popularity of green consumption concepts, cat litter, as an important daily consumable for enhancing the pet's living experience and maintaining a clean and hygienic home, faces two major bottlenecks in its market acceptance: Firstly, the high prices of existing high-performance cat litter products (such as silica gel cat litter and high-end tofu cat litter) deter many pet owners, especially those with multiple pets, from purchasing them, severely limiting their widespread application. Secondly, the mining process of traditional mineral cat litter (such as bentonite cat litter) damages the ecological environment, and its waste is difficult to degrade naturally. Extensive landfilling not only exacerbates solid waste pollution but may also generate dust that affects the respiratory health of humans and pets, posing a potential threat to urban environmental sanitation and ecosystems. Cellulose cat litter, on the other hand, boasts advantages such as strong water absorption, safety and non-toxicity, biodegradability, renewability, and good biocompatibility, making it environmentally friendly. However, traditional cellulose cat litter often suffers from drawbacks such as high cost, slightly poor odor absorption, and clumping properties greatly affected by adhesives. Therefore, developing environmentally friendly cat litter that combines price advantages with high-tech content is not only a key step in breaking the current industry predicament, but also an inevitable choice for promoting the green and high-quality development of the pet supplies industry.

[0003] Fly ash, a major industrial solid waste emitted by coal-fired power plants, is characterized by its wide availability and low cost. It contains elements such as silicon, aluminum, iron, and calcium, and exhibits a porous glass microsphere structure, possessing excellent adsorption and water retention capabilities. Meanwhile, cellulose is the most abundant natural polymer material, widely available and biodegradable. Chemical modification to introduce active groups can endow it with excellent water absorption and cross-linking properties. Using bio-based modified cellulose as a raw material to produce cat litter offers advantages such as biodegradability, renewability, and good biocompatibility, making it environmentally friendly. Furthermore, by incorporating fly ash through cross-linking copolymerization, it overcomes the problems of poor odor absorption and clumping in commercially available cellulose cat litter. Replacing cellulose cat litter with inexpensive fly ash further reduces costs, making it an effective way to achieve high-value utilization of fly ash and promote the green upgrading of cat litter products.

[0004] Therefore, developing a novel composite cat litter based on fly ash and modified cellulose is of great significance. Summary of the Invention

[0005] The technical problem this invention aims to solve is to address the shortcomings of existing technologies by providing a method for preparing fly ash-cellulose composite cat litter. This method utilizes a low-temperature alkaline dissolution system to achieve uniform dissolution of cellulose. Active double bond sites are introduced into the cellulose molecular chain through the etherification reaction of allyl glycidyl ether, overcoming the shortcomings of natural cellulose, such as low reactivity and difficulty in directly participating in free radical polymerization. Simultaneously, industrial solid waste fly ash is activated to prepare molecular sieves. Utilizing its porous structure and high specific surface area, it is uniformly dispersed in the cellulose matrix as a functional filler, overcoming the problems of poor compatibility and easy agglomeration of ordinary fillers with the polymer matrix. By using N,N'-methylenebisacrylamide (MBA) as a crosslinking agent and potassium persulfate (KPS) as an initiator, a copolymerization reaction of allyl cellulose and fly ash is initiated under nitrogen protection to construct an organic-inorganic composite system with a three-dimensional network structure, which can significantly improve the material's water absorption and retention properties and gel strength. In addition, the purification of allyl cellulose by freeze-drying technology can maintain the extended state and reactivity of its molecular chains, which is conducive to the smooth progress of subsequent copolymerization reaction. The copolymer product can be granulated by drying, crushing and screening process to obtain cat litter granules with uniform particle size and stable water absorption performance. The preparation process is simple and controllable and easy to industrialize.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] The first aspect of this invention provides a method for preparing fly ash-cellulose composite cat litter, comprising the following steps:

[0008] S1. Dissolution: Dissolve cellulose in NaOH solution to obtain a homogeneous cellulose-NaOH solution;

[0009] S2. Allyl etherification reaction: Allyl glycidyl ether is added dropwise to a homogeneous cellulose-NaOH solution. After the addition is complete, the temperature is raised to complete the etherification and a crude allyl cellulose solution is obtained.

[0010] S3. Separation of products: After the reaction is complete, the crude allyl cellulose solution is poured into acetone, settled, filtered and washed to obtain allyl cellulose filter cake.

[0011] S4. Dialysis purification: Dissolve the allyl cellulose filter cake in water by stirring to obtain an allyl cellulose aqueous solution, put it into a dialysis bag, and dialyze it in deionized water; the dialysis product is freeze-dried to obtain allyl cellulose;

[0012] S5. Copolymerization: Allyl cellulose is dissolved in water to obtain an allyl cellulose solution. Fly ash, N,N'-methylenebisacrylamide and potassium persulfate are added and stirred to react, resulting in a gel-like product.

[0013] S6. Granulation: Cut the cooled gel-like product into small pieces, wash and dry to constant weight, grind with a mortar and pestle, and then sieve to obtain fly ash-cellulose composite cat litter.

[0014] In S1, the mass ratio of cellulose to NaOH is 1:(1~3); the concentration of NaOH is 5~20wt%; and the dissolution conditions are: the dissolution temperature is 0~-20℃.

[0015] In some embodiments of the present invention, in S1, the cellulose is added to the NaOH solution in multiple additions, specifically by slowly adding it to the low-temperature NaOH aqueous solution in three additions at 5-minute intervals.

[0016] In S2, the mass ratio of allyl glycidyl ether to cellulose is (6~10):1; the condition for the dropwise addition is: 1 drop is added at a dropping rate of 1~5s.

[0017] In some embodiments of the present invention, in S2, the drop-by-drop addition process is carried out entirely at low temperature and under the protection of nitrogen gas.

[0018] In S2, the heating reaction is carried out under the following conditions: temperature 20~40℃ and time 12~36h.

[0019] In S3, the volume ratio of acetone to crude allyl cellulose solution is (1~5):1.

[0020] In some embodiments of the present invention, in S3, the settling time is 10-60 minutes.

[0021] In S4, the dialysis conditions are: time 12~36h, with deionized water replaced every 2~6h; the freeze-drying conditions are: temperature -20~-50℃, time 4~8h.

[0022] In S5, the mass-volume concentration of the allyl cellulose solution is 10%; the amount of fly ash used is 10-30 wt% of allyl cellulose; the amount of N,N'-methylenebisacrylamide used is 0.5-3.0 wt% of allyl cellulose; and the amount of potassium persulfate used is 0.5-5.0 wt% of allyl cellulose.

[0023] In some embodiments of the present invention, in S5, the N,N'-methylenebisacrylamide is a crosslinking agent in the reaction system; and the potassium persulfate is an initiator in the reaction system.

[0024] In S5, the stirring reaction is carried out under the following conditions: under nitrogen protection, the temperature is 50~70℃, and the time is 1~4h.

[0025] In step S6, the drying conditions are: temperature 40~80℃, time 6~12h.

[0026] A second aspect of the present invention provides a fly ash-cellulose composite cat litter.

[0027] The fly ash-cellulose composite cat litter has a particle size of 1~5mm.

[0028] In some embodiments of the present invention, fly ash-cellulose composite cat litter was successfully synthesized by the above method. By comparing fly ash-cellulose composite cat litter with fly ash and cellulose, it is shown that preparing fly ash-cellulose composite cat litter by combining cellulose and fly ash can significantly improve the odor absorption and clumping properties of cellulose.

[0029] Beneficial effects:

[0030] Fly ash, as one of the main industrial solid wastes emitted by coal-fired power plants, is widely available and inexpensive. Its large specific surface area and excellent adsorption performance make it suitable as a functional filler for preparing composite absorbent materials. Cellulose, as the most abundant natural polymer, has advantages such as wide availability, biodegradability, and good hydrophilicity. After low-temperature alkali dissolution to form a homogeneous solution, it is further modified by etherification with allyl glycidyl ether to introduce active double bonds, overcoming the limitation of direct polymerization of natural cellulose. Using N,N'-methylenebisacrylamide as a crosslinking agent and potassium persulfate as an initiator, a copolymerization reaction of allyl cellulose and fly ash was initiated, constructing an organic-inorganic composite system with a three-dimensional network structure. Cat litter made from bio-based modified cellulose has advantages such as being biodegradable, renewable, and having good biocompatibility. It is green and environmentally friendly. At the same time, by incorporating fly ash through cross-linking copolymerization, it can overcome the problems of poor odor absorption and clumping in traditional cellulose cat litter. Furthermore, by replacing it with inexpensive fly ash, the cost of cellulose cat litter is reduced, realizing the high-value utilization of fly ash resources, which has good economic and environmental benefits. Attached Figure Description

[0031] The present invention will be further described in detail below with reference to the accompanying drawings, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0032] Figure 1 This is a flowchart illustrating the preparation process of the novel fly ash-cellulose composite cat litter in this invention. Detailed Implementation

[0033] The present invention will be further described in detail below with reference to specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0034] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; unless otherwise specified, the reagents and materials are commercially available.

[0035] Example 1:

[0036] This invention provides a novel method for preparing fly ash-cellulose composite cat litter. Figure 1 The following is a flowchart illustrating the preparation process of a novel fly ash-cellulose composite cat litter. The specific steps are as follows:

[0037] The cryogenic control system of the ethanol bath was activated, and the temperature was set to -12℃. Stirring and cooling were carried out until the system temperature stabilized, maintaining this low-temperature state. While pre-cooling, a 10wt% NaOH aqueous solution was prepared and cooled to room temperature for later use. The NaOH aqueous solution was added under constant temperature stirring. Microcrystalline cellulose with a mass ratio of 1:2 to NaOH was weighed and slowly added to the low-temperature NaOH aqueous solution in three portions, with 5-minute intervals between additions. Stirring was continued at -12℃ for 2 hours until the cellulose was completely dissolved, forming a transparent or slightly turbid homogeneous cellulose-NaOH solution, at which point there were no obvious solid particles in the system.

[0038] Attach a constant-pressure dropping funnel to the flask interface and add allyl glycidyl ether (AGE) to the funnel at a mass ratio of AGE to microcrystalline cellulose of 8:1. Open the stopcock and, under conditions of maintaining a low temperature of -12°C and a protective nitrogen atmosphere, add AGE to the reaction system at a dropping rate of 1 drop / 4 s. After the addition is complete, turn off the low-temperature system, raise the temperature to 30°C, and continue the reaction under nitrogen protection and stirring for 24 hours.

[0039] After the reaction was complete, the nitrogen gas and stirring were turned off. The crude allyl cellulose solution in the flask was slowly poured into a beaker containing acetone at a volume ratio of 3:1. While pouring, the mixture was gently stirred with a glass rod. At this point, a white flocculent allyl cellulose precipitate formed in the solution. The precipitate was allowed to stand for 30 minutes. The Buchner funnel was then connected to a vacuum filtration flask, lined with filter paper, and the mixture was filtered until no obvious liquid was visible on the surface of the precipitate. The precipitate was then washed three times with acetone to obtain the allyl cellulose filter cake.

[0040] The allyl cellulose filter cake obtained by vacuum filtration was transferred to a beaker, and water was added and stirred to dissolve it, forming an allyl cellulose aqueous solution. After cooling to room temperature, the solution was poured into a pre-treated dialysis bag, and the bag opening was sealed with a dialysis bag clamp to ensure no leakage. The dialysis bag was then placed in a dialysis cup, and water was added for dialysis. The deionized water was changed every 4 hours, and dialysis was performed for 24 hours. After dialysis, the solution was freeze-dried at -40℃ for 6 hours to obtain pure allyl cellulose.

[0041] Allyl cellulose was dissolved in water to obtain an allyl cellulose solution with a mass-volume concentration of 10%. Desulfurization ash from a thermal power plant was used as the original fly ash sample. 15 wt% of fly ash was weighed into the allyl cellulose solution and mixed evenly. 2 wt% N,N'-methylenebisacrylamide (MBA) was added as a crosslinking agent and 1 wt% potassium persulfate (KPS) was added as an initiator. The copolymerization reaction was continued under nitrogen protection and stirring at 65°C for 2.5 h.

[0042] After the reaction was complete, the gel-like product was removed, placed in a petri dish, and allowed to cool to room temperature. It was then cut into small pieces and washed three times with deionized water. The washed product was placed in an oven at 60°C and dried for 10 hours to obtain dried copolymer composite cat litter. This was then ground in a mortar and pestle and sieved to obtain a novel fly ash-cellulose composite cat litter with a particle size of approximately 2 mm.

[0043] Performance testing:

[0044] The performance of the novel fly ash-cellulose composite cat litter prepared in Example 1 was tested, with cellulose and fly ash serving as control groups. The specific experimental steps are as follows:

[0045] Moisture content: Weigh approximately 1g of sample and place it in a drying oven, drying at 105℃ for 2 hours. The percentage is expressed as the ratio of weight loss to weight before drying, rounded to one decimal place.

[0046] Adsorption rate (ammonia adsorption): Weigh 1g of sample and put it into a beaker, place it at the bottom of the desiccator, add 1mL of 0.5% ammonia water to the center of the sample, seal the desiccator tightly, let it stand for 5 minutes, and then use an ammonia detector to detect the percentage change in ammonia content in the desiccator and record the results.

[0047] Liquid absorption rate: Weigh 1g of sample using an electronic balance, place it in a beaker, add water, and record the amount of water that can be completely absorbed (m2) (within 5 minutes after adding water, tilt the beaker at about 30 degrees and no water droplets flow). Water absorption rate P = (m2-m1) / m1*100%.

[0048] Accurately weigh 1g of sample (m1) and place it in a clean beaker. Slowly add water. Let it stand for 5 minutes until it is fully absorbed. Tilt the beaker at about 30° and use the point where there are no more water droplets on the beaker wall and bottom as the endpoint for drying. Then weigh the total mass (m2). The formula for calculating the absorption rate is: P = (m2 - m1) / m1 × 100%.

[0049] Clumping: 1g of sample was placed in a plastic box, 5mL of tap water was measured with a measuring cup and poured into the cat litter in a stream, and the time it took to clump was observed and recorded with a stopwatch.

[0050] Table 1 compares the key indicators of cellulose, fly ash, and fly ash-cellulose composite cat litter. As can be seen from Table 1, cellulose alone has good water absorption, but slightly poor odor absorption and clumping properties. Fly ash alone has poor water absorption, but good adsorption rate and clumping properties. Combining cellulose and fly ash to prepare fly ash-cellulose composite cat litter can significantly improve the odor absorption and clumping properties of cellulose.

[0051] Table 1. Comparison of key indicators for cellulose, fly ash, and fly ash-cellulose composite cat litter.

[0052] Cellulose 9.7% 6.7% 355% 6 fly ash 0.45% 10.2% 253% 4 Fly ash-cellulose composite cat litter 9.2% 7.7% 322% 4.5

[0053] Example 2:

[0054] Turn on the cryogenic control system of the ethanol bath, set the temperature to 0℃, and stir to cool. After the system temperature stabilizes, maintain the low temperature. While pre-cooling, prepare a 5wt% NaOH aqueous solution and cool it to room temperature for later use. Add the NaOH aqueous solution while stirring at a low temperature. Weigh out microcrystalline cellulose with a mass ratio of 1:1 to NaOH, and slowly add it to the low-temperature NaOH aqueous solution in three portions, with 5-minute intervals. Continue stirring at 0℃ for 2 hours until the cellulose is completely dissolved, forming a transparent or slightly turbid homogeneous cellulose-NaOH solution. At this point, there are no obvious solid particles in the system.

[0055] Install a constant-pressure dropping funnel on the flask interface and add allyl glycidyl ether (AGE) to the funnel at a mass ratio of 6:1 to microcrystalline cellulose. Open the stopcock and add AGE to the reaction system at a rate of 1 drop per 1 second, maintaining a low temperature of 0°C and a protective nitrogen atmosphere. After the addition is complete, turn off the low-temperature system, raise the temperature to 20°C, and continue the reaction under nitrogen protection and stirring for 12 hours.

[0056] After the reaction was complete, the nitrogen gas and stirring were turned off. The crude allyl cellulose solution in the flask was slowly poured into a beaker containing acetone at a volume ratio of 1:1. While pouring, the mixture was gently stirred with a glass rod. At this point, a white flocculent allyl cellulose precipitate formed in the solution. The precipitate was allowed to stand for 10 minutes. The Buchner funnel was then connected to a vacuum filtration flask, lined with filter paper, and the mixture was filtered until no obvious liquid was visible on the surface of the precipitate. The precipitate was then washed three times with acetone to obtain an allyl cellulose filter cake.

[0057] The allyl cellulose filter cake obtained by vacuum filtration was transferred to a beaker, and water was added and stirred to dissolve it, forming an allyl cellulose aqueous solution. After cooling to room temperature, the solution was poured into a pre-treated dialysis bag, and the bag opening was sealed with a dialysis bag clamp to ensure no leakage. The dialysis bag was then placed in a dialysis cup, and water was added for dialysis. The deionized water was changed every 2 hours, and dialysis was performed for 12 hours. After dialysis, the solution was freeze-dried at -20℃ for 4 hours to obtain pure allyl cellulose.

[0058] Allyl cellulose was dissolved in water to obtain an allyl cellulose solution with a mass-volume concentration of 10%. Desulfurization ash from a thermal power plant was used as the original fly ash sample. 10 wt% of fly ash was weighed into the allyl cellulose solution and mixed evenly. 0.5 wt% N,N'-methylenebisacrylamide (MBA) was added as a crosslinking agent and 0.5 wt% potassium persulfate (KPS) was added as an initiator. The copolymerization reaction was continued under nitrogen protection and stirring at 50°C for 1 hour.

[0059] After the reaction was complete, the gel-like product was removed, placed in a petri dish, and allowed to cool to room temperature. It was then cut into small pieces and washed three times with deionized water. The washed product was placed in an oven at 40°C and dried for 6 hours to obtain dried copolymer composite cat litter. This was then ground in a mortar and pestle and sieved to obtain a novel fly ash-cellulose composite cat litter with a particle size of approximately 1 mm.

[0060] Performance testing:

[0061] The performance of the novel fly ash-cellulose composite cat litter prepared in Example 2 was tested according to the performance testing method in Example 1, while cellulose and fly ash were used as control groups.

[0062] Table 2 compares the key indicators of cellulose, fly ash, and fly ash-cellulose composite cat litter. As can be seen from Table 2, cellulose alone has good water absorption, but slightly poor odor absorption and clumping properties. Fly ash alone has poor water absorption, but good adsorption rate and clumping properties. Fly ash-cellulose composite cat litter prepared by combining cellulose and fly ash can significantly improve the odor absorption and clumping properties of cellulose.

[0063] Table 2 Comparison of key indicators for cellulose, fly ash, and fly ash-cellulose composite cat litter

[0064] Cellulose 9.7% 6.7% 355% 6 fly ash 0.45% 10.2% 253% 4 Fly ash-cellulose composite cat litter 9.0% 7.2% 304% 4.8

[0065] Example 3:

[0066] The cryogenic control system of the ethanol bath was activated, and the temperature was set to -20°C. Stirring and cooling were carried out until the system temperature stabilized, maintaining this low-temperature state. While pre-cooling, a 20wt% NaOH aqueous solution was prepared and cooled to room temperature for later use. The NaOH aqueous solution was added under constant temperature stirring at low temperature. Microcrystalline cellulose with a mass ratio of 1:3 to NaOH was weighed and slowly added to the low-temperature NaOH aqueous solution in three portions, with 5-minute intervals between additions. Stirring was continued at -20°C for 2 hours until the cellulose was completely dissolved, forming a transparent or slightly turbid homogeneous cellulose-NaOH solution, at which point there were no obvious solid particles in the system.

[0067] Attach a constant-pressure dropping funnel to the flask interface and add allyl glycidyl ether (AGE) to the funnel at a mass ratio of AGE to microcrystalline cellulose of 10:1. Open the stopcock and add AGE to the reaction system at a rate of 1 drop per 5 seconds, maintaining a low temperature of -20°C and a protective nitrogen atmosphere. After the addition is complete, turn off the low-temperature system, raise the temperature to 40°C, and continue the reaction under nitrogen protection and stirring for 36 hours.

[0068] After the reaction was complete, the nitrogen gas and stirring were turned off. The crude allyl cellulose solution in the flask was slowly poured into a beaker containing acetone at a volume ratio of 5:1. While pouring, the mixture was gently stirred with a glass rod. At this point, a white flocculent allyl cellulose precipitate formed in the solution. The precipitate was allowed to stand for 60 minutes. The Buchner funnel was then connected to a vacuum filtration flask, lined with filter paper, and the mixture was filtered until no obvious liquid was visible on the surface of the precipitate. The precipitate was then washed three times with acetone to obtain the allyl cellulose filter cake.

[0069] The allyl cellulose filter cake obtained by vacuum filtration was transferred to a beaker, and water was added and stirred to dissolve it, forming an allyl cellulose aqueous solution. After cooling to room temperature, the solution was poured into a pre-treated dialysis bag, and the bag opening was sealed with a dialysis bag clamp to ensure no leakage. The dialysis bag was then placed in a dialysis cup, and water was added for dialysis. The deionized water was changed every 6 hours, and dialysis was performed for 36 hours. After dialysis, the solution was freeze-dried at -50℃ for 8 hours to obtain pure allyl cellulose.

[0070] Allyl cellulose was dissolved in water to obtain an allyl cellulose solution with a mass-volume concentration of 10%. Desulfurization ash from a thermal power plant was used as the original fly ash sample. 30 wt% of fly ash was weighed and added to the allyl cellulose solution and mixed evenly. 3 wt% N,N'-methylenebisacrylamide (MBA) was added as a crosslinking agent and 5 wt% potassium persulfate (KPS) was added as an initiator. The copolymerization reaction was continued under nitrogen protection and stirring at 70°C for 4 hours.

[0071] After the reaction was complete, the gel-like product was removed, placed in a petri dish, and allowed to cool to room temperature. It was then cut into small pieces and washed three times with deionized water. The washed product was placed in an oven at 80°C and dried for 12 hours to obtain dried copolymer composite cat litter. This was then ground in a mortar and pestle and sieved to obtain a novel fly ash-cellulose composite cat litter with a particle size of approximately 5 mm.

[0072] Performance testing:

[0073] The performance of the novel fly ash-cellulose composite cat litter prepared in Example 3 was tested according to the performance testing method in Example 1, while cellulose and fly ash were used as control groups.

[0074] Table 3 compares the key indicators of cellulose, fly ash, and fly ash-cellulose composite cat litter. As can be seen from Table 3, cellulose alone has good water absorption, but slightly poor odor absorption and clumping properties. Fly ash alone has poor water absorption, but good adsorption rate and clumping properties. Fly ash-cellulose composite cat litter prepared by combining cellulose and fly ash can significantly improve the odor absorption and clumping properties of cellulose.

[0075] Table 3 Comparison of key indicators for cellulose, fly ash, and fly ash-cellulose composite cat litter

[0076] Cellulose 9.7% 6.7% 355% 6 fly ash 0.45% 10.2% 253% 4 Fly ash-cellulose composite cat litter 9.5% 7.3% 311% 5.3

[0077] This invention provides a method for preparing fly ash-cellulose composite cat litter. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A method for preparing fly ash-cellulose composite cat litter, characterized in that, Includes the following steps: S1. Dissolution: Dissolve cellulose in NaOH solution to obtain a homogeneous cellulose-NaOH solution; S2. Allyl etherification reaction: Allyl glycidyl ether is added dropwise to a homogeneous cellulose-NaOH solution. After the addition is complete, the temperature is raised to complete the etherification and a crude allyl cellulose solution is obtained. S3. Separation of products: After the reaction is complete, the crude allyl cellulose solution is poured into acetone, settled, filtered and washed to obtain allyl cellulose filter cake. S4. Dialysis purification: Dissolve the allyl cellulose filter cake in water by stirring to obtain an allyl cellulose aqueous solution, put it into a dialysis bag, and dialyze it in deionized water; the dialysis product is freeze-dried to obtain allyl cellulose; S5. Copolymerization: Allyl cellulose is dissolved in water to obtain an allyl cellulose solution. Fly ash, N,N'-methylenebisacrylamide and potassium persulfate are added and stirred to react, resulting in a gel-like product. S6. Granulation: Cut the cooled gel-like product into small pieces, wash and dry to constant weight, grind with a mortar and pestle, and then sieve to obtain fly ash-cellulose composite cat litter.

2. The preparation method according to claim 1, characterized in that, In S1, the mass ratio of cellulose to NaOH is 1:(1~3); the concentration of NaOH is 5~20wt%; the dissolution conditions are: the dissolution temperature is 0~-20℃.

3. The preparation method according to claim 1, characterized in that, In S2, the mass ratio of allyl glycidyl ether to cellulose is (6~10):1; the condition for the dropwise addition is: the dropping rate is 1 drop per 1~5 seconds.

4. The preparation method according to claim 1, characterized in that, In S2, the heating reaction is carried out under the following conditions: temperature 20~40℃, time 12~36h.

5. The preparation method according to claim 1, characterized in that, In S3, the volume ratio of acetone to crude allyl cellulose solution is (1~5):

1.

6. The preparation method according to claim 1, characterized in that, In S4, the dialysis conditions are: time of 12~36h, with deionized water replaced every 4~6h; the freeze-drying conditions are: temperature of -20~-50℃, time of 4~8h.

7. The preparation method according to claim 1, characterized in that, In S5, the mass-volume concentration of the allyl cellulose solution is 10%; the amount of fly ash used is 10-30 wt% of allyl cellulose; the amount of N,N'-methylenebisacrylamide used is 0.5-3.0 wt% of allyl cellulose; and the amount of potassium persulfate used is 0.5-5.0 wt% of allyl cellulose.

8. The preparation method according to claim 1, characterized in that, In S5, the stirring reaction is carried out under the following conditions: under nitrogen protection, the temperature is 50~70℃, and the time is 1~4h.

9. The fly ash-cellulose composite cat litter prepared by the preparation method according to any one of claims 1 to 8.

10. The fly ash-cellulose composite cat litter according to claim 9, characterized in that, The particle size of the fly ash-cellulose composite cat litter is 1~5mm.

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