Functional cellulose composite aerogel for water treatment and preparation method thereof

Abstract

The invention relates to functionalized cellulose composite aerogel for water treatment and a preparation method thereof. The preparation method comprises the following steps: firstly, growing ZIF-8 between MXene layers in situ; then mixing the obtained ZIF-8-coated MXene material with AM and 2-AMPS, carrying out in-situ growth of a star polymer under the initiation of a star chain transfer agent and an initiator, and finally dispersing the compound in a sodium carboxymethyl cellulose aqueous solution to form the lightweight porous composite aerogel. The star polymer is adopted to synergistically construct the composite aerogel of the ZIF-8 (at) MXene composite material and the cellulose, the star polymer provides abundant acylamino and sulfonic acid group adsorption sites, the star polymer, the ZIF-8 and MXene materials generate a synergistic interaction effect, and the adsorption capacity on metal ions and organic matters is remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of water treatment, in particular to a functionalized cellulose composite aerogel for water treatment and a preparation method thereof. BACKGROUND

[0002] Water resources are the cornerstone of human survival and development. However, with the accelerating process of global industrialization and the continuous growth of population, a large amount of industrial wastewater containing heavy metal ions (such as lead, cadmium, copper, chromium) and refractory organic pollutants (such as dyes, antibiotics) is discharged into water bodies, leading to increasingly serious water environmental pollution problems, which seriously affects the balance of the ecological system and human health and safety.

[0003] The core goal of water treatment technology is to efficiently remove these pollutants to ensure drinking water safety and achieve wastewater resource recycling. Among the numerous water treatment technologies, adsorption method is widely used due to its simple operation, relatively low cost, wide applicability and less secondary pollution. Activated carbon, zeolite, silica gel and polymer resin are traditional adsorbents, but they usually have inherent defects such as limited adsorption capacity, slow adsorption rate, poor selectivity for specific pollutants and difficult regeneration.

[0004] In order to overcome the limitations of traditional adsorbents, nanomaterials have attracted great interest as a new generation of high-efficiency adsorbents due to their extremely high specific surface area and abundant surface active sites. MXene is a kind of two-dimensional inorganic compound with a structure similar to graphene, mainly composed of metal carbide or nitride. This material has high specific surface area, excellent electronic transmission performance and strong interface coupling effect, and also shows good hydrophilicity and conductivity, so it is widely used in sensing, energy storage, catalytic degradation and adsorption and other fields. However, although there are many studies on the performance of MXene materials, their application in water pollutant adsorption is still relatively rare.

[0005] Cellulose aerogel, as a kind of green carrier material, has the characteristics of wide source, biodegradability and excellent mechanical properties, and its through-porous structure provides an ideal channel for pollutant transmission, making it an ideal carrier for constructing high-efficiency adsorbents. Although some studies have tried to combine nanomaterials with aerogels, most of the work only realizes physical blending, and the active components are easily leached out, with single function. At present, there is an urgent need for a design strategy to integrate multiple functional materials into the three-dimensional network of cellulose aerogel through firm chemical action, to construct a multifunctional integrated composite material with high adsorption capacity, fast adsorption kinetics, excellent mechanical stability and easy recovery characteristics, so as to realize the efficient synchronous removal of multiple pollutants in complex wastewater. SUMMARY

[0006] In view of the deficiencies in the prior art, the cellulose aerogel is used as a carrier material, is compounded with a two-dimensional material MXene, star-shaped block polymers are formed on the surface thereof through in-situ polymerization to improve the stability of the aerogel material, and can be used for treating organic pollutants and metal ions in water bodies.

[0007] To achieve the above object, the application provides the following technical scheme. A preparation method of a functionalized cellulose composite aerogel for water treatment, comprising the following steps: S1, ultrasonic dispersion of MXene in deionized water, sequentially adding Zn(NO3)2·6H2O and 2-methylimidazole, continuing ultrasonic dispersion for 30 min to make it fully dispersed, transferring the mixed solution to a 100 mL polytetrafluoroethylene-lined high-pressure reaction kettle, reacting at 120 DEG C for 12 h, naturally cooling, centrifugal collection of the precipitate, washing with water and ethanol each three times, and vacuum drying at 60 DEG C to obtain a ZIF-8@MXene composite material; S2, ultrasonic dispersion of the ZIF-8@MXene material in a reaction bottle containing DMF, purging the system of air by introducing nitrogen, adding a star-shaped chain transfer agent (CTA), acrylamide (AM) and 2-acrylamido-2-methylpropanesulfonic acid (AMPS), continuing to introduce nitrogen and heating to 70 DEG C; dissolving the initiator in DMF, then adding it dropwise into the reaction bottle under the protection of nitrogen, continuing to stir for 8-12 h after the dropwise addition is completed; after the reaction is completed, diluting with THF, then pouring into ice ether, filtering, and drying the solid to obtain; S3, dispersing the solid of step S2 in a carboxymethyl cellulose sodium aqueous solution, adding N,N'-methylenebisacrylamide, ultrasonic dispersion for 2 h to form a uniform slurry, injecting the slurry into a cylindrical mold, pre-reacting at 50-60 DEG C for 4-6 h, then freezing at-80 DEG C for 12 h, and transferring to a freeze dryer for freeze drying for 24 h to obtain a light and porous composite aerogel.

[0008] Further, the preparation process of the MXene is as follows: Dissolving LiF in an HCl solution with a concentration of 6-12 M, slowly adding Ti3AlC2 powder, reacting at 30-40 DEG C for 18-36 h, centrifugal washing until the pH value of the supernatant is 5-7 after the reaction is completed, and finally obtaining a few-layer MXene dispersion liquid through ultrasonic peeling and centrifugation.

[0009] Further, in step S1, the mass ratio of MXene to Zn(NO3)2·6H2O is 1:1-5.

[0010] Further, the preparation process of the star-shaped chain transfer agent is as follows: 1) In a reaction bottle, 1 equivalent of dipentaerythritol was added, the reaction bottle was placed in an ice water bath, then DMF was added dropwise under nitrogen protection, after the solid was completely dissolved, 6 equivalents of chloroacetyl chloride was slowly added dropwise, the system temperature was maintained below 35 DEG C, the reaction was carried out for 2 h, then the temperature was controlled at 40 DEG C and reacted overnight, deionized water was added to the reaction liquid, and a light yellow solid was precipitated, which was filtered and dried for use; 2) The light yellow solid of step 1) was added to a single neck flask, THF was added to stir to dissolve, then dithiobenzoic acid THF solution was added dropwise, after the dropwise addition was completed, the temperature in the reactor was adjusted to 40 DEG C, and the reaction was carried out for 10 h, then it was filtered, the filtrate was rotary evaporated to remove the solvent, after adding sodium hydroxide solution, it was washed repeatedly with distilled water, then it was dissolved in THF and distilled under reduced pressure to obtain.

[0011] Further, in the step S3, the molar ratio of acrylamide, 2-acrylamido-2-methylpropane sulfonic acid, star chain transfer agent and initiator is 500-700:300-500:5:0.1; the initiator is AIBN.

[0012] Further, in the step S3, the mass ratio of ZIF-8@MXene material to the total of acrylamide and 2-acrylamido-2-methylpropane sulfonic acid monomers is 1:5-20.

[0013] Further, in the step S3, the mass ratio of solid to carboxymethyl cellulose sodium and N,N'-methylene bisacrylamide is 1:1-10:0.02-0.05.

[0014] The application further provides a functionalized cellulose composite aerogel for water treatment prepared according to the preparation method.

[0015] MXene materials have been proven to be able to be applied in wastewater treatment, but its application is limited by the problems such as the reduction of effective adsorption sites caused by the easy stacking of nanosheets, and the difficulty in recycling in the form of nano powder, and there are still many things that can be improved. In this application, ZIF nanoparticles are grown in situ between the layers of the prepared MXene material, and the ZIF provides a large specific surface area and a porous structure, which can enhance the adsorption capacity of water pollutants. Then disperse the ZIF nanoparticle loaded MXene material in the monomer solution of acrylamide and 2-acrylamido-2-methylpropanesulfonic acid, and the active sites on the surface of the ZIF particles can promote the in-situ polymerization of the monomers between the layers and on the surface of the MXene material. In this application, the inventors prepared a star-shaped chain transfer agent, which can promote the RAFT polymerization of AM and AMPS to form a star-shaped copolymer. Compared with traditional linear polymers, the star-shaped polymer has a multi-dimensional long chain, like an "octopus", which can form multiple anchor points on the surface of a ZIF-8@MXene particle through the functional groups at the end of the arm. This multi-point anchoring effect provides stronger steric hindrance, which can more effectively and stably prevent nanoparticles from approaching each other, thereby achieving superdispersion effect, and making the active components more evenly distributed in the final aerogel skeleton. In addition, the star-shaped polymer chain can also be connected with the cellulose molecular chain, and under the further action of the crosslinking agent, the active nano components are firmly nailed to the cellulose skeleton, thereby forming a more dense, uniform and stable three-dimensional network structure, which significantly improves the mechanical strength and structural stability of the final aerogel. The adsorption capacity and adsorption rate of the aerogel are also significantly improved.

[0016] Compared with the prior art, the beneficial effects of the present application are: the present application adopts a star-shaped polymer to cooperatively construct a ZIF-8@MXene composite material and a composite aerogel of cellulose, the star-shaped polymer provides abundant amido and sulfonic acid adsorption sites, and has a synergistic effect with ZIF-8 and MXene material, which significantly improves the adsorption efficiency of metal ions and organic matter. DETAILED DESCRIPTION

[0017] The technical solutions of the present application will be described below in conjunction with the embodiments, obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0018] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0019] The raw materials used in the present application can be directly purchased from the market unless otherwise specified. The preparation process of the star-shaped chain transfer agent used in the present application is as follows: 1) Add 1 equivalent of dipentaerythritol to a reaction bottle, place the reaction bottle in an ice water bath, then add DMF dropwise under nitrogen protection. After the solid is completely dissolved, slowly add 6 equivalents of chloroacetyl chloride to the system, and maintain the temperature below 35°C. React for 2 h, then control the temperature at 40°C overnight. Add deionized water to the reaction liquid, and precipitate a light yellow solid. Filter and dry for use. 2) Add the light yellow solid of step 1) to a single-neck flask, add tetrahydrofuran (THF) and stir to dissolve. Then add a THF solution of dithiobenzoic acid dropwise. After the dropwise addition is complete, adjust the temperature in the reactor to 40°C and react for 10 h. Filter, remove the solvent from the filtrate by rotary evaporation, wash with sodium hydroxide solution and distilled water repeatedly, dissolve in THF, and distill under reduced pressure to obtain a six-armed star-shaped chain transfer agent CTA.

[0020] Example 1: Prepare a composite aerogel as follows: S1, weigh 1 g of LiF and add it to 20 mL of 9M HCl solution and stir until dissolved. Slowly add 1 g of Ti3AlC2 powder under ice water bath conditions, and react at 35°C for 24 h. After the reaction is completed, repeatedly centrifuge and wash with deionized water until the supernatant pH ≈ 6. Finally, redispersed the precipitate in deionized water and ultrasonic for 1 h to obtain a MXene dispersion liquid with a concentration of 2 mg / mL.

[0021] S2, take 250 mL of the above MXene dispersion liquid and ultrasonic for 30 min. Add 0.5 g of Zn(NO3)2·6H2O and 0.3 g of 2-methylimidazole successively, and continue to ultrasonic for 30 min to make them fully dispersed. Transfer the mixture to a 100 mL polytetrafluoroethylene-lined high-pressure reaction kettle, and react at 120°C for 12 h. After natural cooling, centrifuge to collect the precipitate, wash with water and ethanol three times each, and vacuum dry at 60°C to obtain ZIF-8@MXene composite material.

[0022] S3, 1 g of ZIF-8@MXene composite was weighed and dispersed in 200 mL of DMF for 1 h. 750 mg (0.5 mmol) of CTA was added, and the nitrogen was stirred for 30 min. Then 4.9 g of AM and 6 g of AMPS (molar ratio 7:3) were added, and the nitrogen was continued to be stirred and heated to 70°C. 1.6 mg of AIBN was dissolved in 2 mL of DMF, and was slowly added to the reaction solution with a dropping funnel, and the reaction was continued at 70°C under nitrogen protection for 10 h. After the reaction was completed, THF was added for dilution, and was poured into ice ethanol for precipitation, and was filtered, and the solid was washed with ethanol three times, and was dried at 60°C under vacuum to obtain a solid product.

[0023] S4, 5 g of sodium carboxymethyl cellulose (CMC) was weighed and dissolved in 20 mL of deionized water, and was stirred until completely dissolved. 1 g of the solid obtained in step S3 and 25 mg of N,N'-methylenebisacrylamide (MBA) were added, and were ultrasonically treated for 2 h to form a uniform slurry. The slurry was injected into a mold, and was heated at 55°C in a water bath for 5 h to form a stable hydrogel. The hydrogel was frozen at -80°C for 12 h, and was then transferred to a freeze dryer for freeze drying for 24 h to obtain a composite aerogel.

[0024] Example 2: S1, 1 g of LiF was weighed and added to 20 mL of 9M HCl solution, and was stirred until dissolved. Under ice water bath conditions, 1 g of Ti3AlC2 powder was slowly added, and was reacted at 35°C for 24 h. After the reaction was completed, the supernatant was repeatedly washed by centrifugation with deionized water until the pH of the supernatant was about 6, and finally the precipitate was redispersed in deionized water, and was ultrasonically treated for 1 h. After centrifugation, the supernatant was obtained to obtain a MXene dispersion solution with a concentration of 2 mg / mL.

[0025] S2, 150 mL of the above MXene dispersion solution was ultrasonically treated for 30 min. 0.5 g of Zn(NO3)2·6H2O and 0.3 g of 2-methylimidazole were added in sequence, and were continuously ultrasonically treated for 30 min to make them fully dispersed. The mixture was transferred to a 100 mL polytetrafluoroethylene-lined high-pressure reaction kettle, and was reacted at 120°C for 12 h. After natural cooling, the precipitate was collected by centrifugation, and was washed with water and ethanol three times each, and was dried at 60°C under vacuum to obtain a ZIF-8@MXene composite material.

[0026] S3, 2 g of ZIF-8@MXene composite was weighed and dispersed in 200 mL of DMF for 1 h. 750 mg (0.5 mmol) of CTA was added, and the nitrogen was stirred for 30 min. Then 4.9 g of AM and 6 g of AMPS (molar ratio 7:3) were added, and the nitrogen was continued to be stirred and heated to 70°C. 1.6 mg of AIBN was dissolved in 2 mL of DMF, and was slowly added to the reaction solution with a dropping funnel, and the reaction was continued at 70°C under nitrogen protection for 10 h. After the reaction was completed, THF was added for dilution, and was poured into ice ethanol for precipitation, and was filtered, and the solid was washed with ethanol three times, and was dried at 60°C under vacuum to obtain a solid product.

[0027] S4, 6 g of sodium carboxymethyl cellulose (CMC) was weighed and dissolved in 20 mL of deionized water, and was stirred until completely dissolved. 1 g of the solid obtained in step S3 and 25 mg of N,N'-methylenebisacrylamide (MBA) were added, and were ultrasonically treated for 2 h to form a uniform slurry. The slurry was injected into a mold, and was heated at 55°C in a water bath for 5 h to form a stable hydrogel. The hydrogel was frozen at -80°C for 12 h, and was then transferred to a freeze dryer for freeze drying for 24 h to obtain a composite aerogel.

[0028] Example 3: S1, 1 g of LiF was weighed and added to 20 mL of 9M HCl solution, and was stirred until dissolved. Under ice water bath conditions, 1 g of Ti3AlC2 powder was slowly added, and was reacted at 35°C for 24 h. After the reaction was completed, the supernatant was repeatedly washed by centrifugation with deionized water until the pH of the supernatant was about 6, and finally the precipitate was redispersed in deionized water, and was ultrasonically treated for 1 h, and the supernatant was obtained after centrifugation to obtain a MXene dispersion solution with a concentration of 2 mg / mL.

[0029] S2, 50 mL of the above MXene dispersion solution was ultrasonically treated for 30 min. 0.5 g of Zn(NO3)2·6H2O and 0.3 g of 2-methylimidazole were added in sequence, and were continuously ultrasonically treated for 30 min to make them fully dispersed. The mixture was transferred to a 100 mL polytetrafluoroethylene-lined high-pressure reaction kettle, and was reacted at 120°C for 12 h. After natural cooling, the precipitate was collected by centrifugation, and was washed with water and ethanol three times each, and was dried at 60°C under vacuum to obtain a ZIF-8@MXene composite material.

[0030] S3, 1 g of ZIF-8@MXene composite was weighed and dispersed in 200 mL of DMF for 1 h. 750 mg (0.5 mmol) of CTA was added, and nitrogen was bubbled for 30 min. Then 2.5 g of AM and 7.4 g of AMPS (molar ratio 5:5) were added, and nitrogen was continued to be bubbled and the temperature was raised to 70°C. 1.6 mg of AIBN was dissolved in 2 mL of DMF and slowly added to the reaction solution with a dropping funnel, and the reaction was continued at 70°C under nitrogen protection for 10 h. After the reaction was completed, THF was added for dilution, and the mixture was poured into ice ethanol for precipitation. The solid was filtered, washed with ethanol three times, and dried at 60°C under vacuum to obtain a solid product.

[0031] S4, 6 g of sodium carboxymethyl cellulose (CMC) was weighed and dissolved in 20 mL of deionized water, and stirred until completely dissolved. 1 g of the solid obtained in step S3 and 25 mg of N,N'-methylenebisacrylamide (MBA) were added, and ultrasonic treatment was performed for 2 h to form a uniform slurry. The slurry was poured into a mold and heated at 55°C in a water bath for 5 h to form a stable hydrogel. The hydrogel was frozen at -80°C for 12 h, and then transferred to a freeze dryer for freeze drying for 24 h to obtain a composite aerogel.

[0032] Comparative Example 1 S1, 1 g of LiF was weighed and added to 20 mL of 9M HCl solution, and stirred until dissolved. Under ice water bath conditions, 1 g of Ti3AlC2 powder was slowly added, and the reaction was carried out at 35°C for 24 h. After the reaction was completed, the mixture was repeatedly washed by centrifugation with deionized water until the pH of the supernatant was about 6, and finally the precipitate was dried to obtain a MXene material.

[0033] S2, 1 g of the MXene material was weighed and dispersed in 200 mL of DMF for 1 h. 750 mg (0.5 mmol) of CTA was added, and nitrogen was bubbled for 30 min. Then 4.9 g of AM and 6 g of AMPS (molar ratio 7:3) were added, and nitrogen was continued to be bubbled and the temperature was raised to 70°C. 1.6 mg of AIBN was dissolved in 2 mL of DMF and slowly added to the reaction solution with a dropping funnel, and the reaction was continued at 70°C under nitrogen protection for 10 h. After the reaction was completed, THF was added for dilution, and the mixture was poured into ice ethanol for precipitation. The solid was filtered, washed with ethanol three times, and dried at 60°C under vacuum to obtain a solid product.

[0034] S3, 5 g of carboxymethyl cellulose sodium (CMC) was weighed into 20 mL of deionized water and stirred until completely dissolved. 1 g of the solid obtained in step S2 and 25 mg of N,N'-methylenebisacrylamide (MBA) were added, and a uniform slurry was formed by ultrasonic treatment for 2 h. The slurry was injected into a mold and heated in a water bath at 55°C for 5 h to form a stable hydrogel. The hydrogel was frozen at -80°C for 12 h and then transferred to a freeze dryer for freeze drying for 24 h to obtain a composite aerogel.

[0035] Comparative Example 2: Composite aerogel was prepared according to the following steps: S1, 1 g of LiF was weighed into 20 mL of 9M HCl solution and stirred until dissolved. Under ice water bath conditions, 1 g of Ti3AlC2 powder was slowly added and reacted at 35°C for 24 h. After the reaction was completed, the precipitate was repeatedly washed by centrifugation with deionized water until the supernatant pH≈6, and finally the precipitate was redispersed in deionized water and ultrasonically stripped for 1 h to obtain a MXene dispersion with a concentration of 2 mg / mL.

[0036] S2, 250 mL of the above MXene dispersion was ultrasonically treated for 30 min. 0.5 g of Zn(NO3)2·6H2O and 0.3 g of 2-methylimidazole were added in turn, and the mixture was ultrasonically treated for another 30 min to ensure complete dispersion. The mixture was transferred to a 100 mL polytetrafluoroethylene-lined high-pressure reaction kettle and reacted at 120°C for 12 h. After natural cooling, the precipitate was collected by centrifugation and washed with water and ethanol three times each, and then vacuum dried at 60°C to obtain a ZIF-8@MXene composite material.

[0037] S3, 1 g of the ZIF-8@MXene composite material was dispersed in 200 mL of DMF and ultrasonically treated for 1 h, and then stirred under nitrogen for 30 min. Then 4.9 g of AM and 6 g of AMPS (molar ratio 7:3) were added, and the reaction was continued under nitrogen and heated to 70°C. 1.6 mg of AIBN was dissolved in 2 mL of DMF and slowly added to the reaction solution through a dropping funnel, and the reaction was continued at 70°C under nitrogen for 10 h. After the reaction was completed, THF was added for dilution, and the mixture was poured into ice ethanol to precipitate, filtered, and the solid was washed with ethanol three times, and then vacuum dried at 60°C to obtain a solid product.

[0038] S4, 5 g of carboxymethyl cellulose sodium (CMC) was weighed into 20 mL of deionized water and stirred until completely dissolved. 1 g of the solid obtained in step S3 and 25 mg of N,N'-methylenebisacrylamide (MBA) were added, and a uniform slurry was formed by ultrasonic treatment for 2 h. The slurry was injected into a mold and heated in a water bath at 55°C for 5 h to form a stable hydrogel. The hydrogel was frozen at -80°C for 12 h and then transferred to a freeze dryer for freeze drying for 24 h to obtain a composite aerogel.

[0039] Comparative Example 3: S1, 1 g of LiF was weighed and added to 20 mL of 9M HCl solution and stirred until dissolved. Under ice water bath conditions, 1 g of Ti3AlC2 powder was slowly added and reacted at 35°C for 24 h. After the reaction, the supernatant was repeatedly washed with deionized water until the pH was about 6, and finally the precipitate was redispersed in deionized water and ultrasonically exfoliated for 1 h to obtain a MXene dispersion solution with a concentration of 2 mg / mL.

[0040] S2, 250 mL of the above MXene dispersion solution was ultrasonically treated for 30 min. 0.5 g of Zn(NO3)2·6H2O and 0.3 g of 2-methylimidazole were added in turn, and the mixture was ultrasonically treated for 30 min to ensure complete dispersion. The mixture was transferred to a 100 mL polytetrafluoroethylene-lined high-pressure reaction kettle and reacted at 120°C for 12 h. After natural cooling, the precipitate was collected by centrifugation and washed with water and ethanol three times each, and vacuum dried at 60°C to obtain ZIF-8@MXene composite material.

[0041] S3, 5 g of carboxymethyl cellulose sodium (CMC) was weighed and dissolved in 20 mL of deionized water and stirred until completely dissolved. 1 g of ZIF-8@MXene composite material was added and ultrasonically treated for 2 h to form a uniform slurry. The slurry was injected into a mold, frozen at -80°C for 12 h, and then transferred to a freeze dryer for freeze drying for 24 h to obtain a composite aerogel.

[0042] Simulated wastewater: Heavy metal ions: Pb 2+ , Cu 2+ (concentration: 50 mg / L). Organic pollutants: phenol, methyl orange (concentration: 50 mg / L).

[0043] The aerogels prepared in Examples 1-3 and Comparative Examples 1-3 above were added to the simulated wastewater at a concentration of 100 mg / L for adsorption experiments.

[0044] Table 1 Direct mixing of ZIF-8@MXene composite material and cellulose to form an aerogel resulted in poor final performance of the aerogel due to weak binding force. If a linear polymer is added to the composite material, the adsorption efficiency of the aerogel can also be effectively improved, but it is still inferior to Examples 1-3. The multi-point anchoring effect brought by the star-shaped polymer greatly improves the removal rate of pollutants. In addition, by observing Comparative Example 1, the introduction of ZIF-8 material can also effectively improve the adsorption capacity of the aerogel for heavy metal ions and organic pollutants.

[0045] While embodiments of the application have been disclosed in connection with the preferred embodiments of the application, it should be understood that there can be other embodiments which fall within the broad concept of the application as defined in the claims and their equivalents.

Claims

1. A method for preparing a functionalized cellulose composite aerogel for water treatment, characterized in that, Includes the following steps: S1. MXene was ultrasonically dispersed in deionized water, and Zn(NO3)2·6H2O and 2-methylimidazole were added sequentially. The mixture was ultrasonically dispersed for 30 min. The mixture was then transferred to a 100 mL high-pressure reactor lined with polytetrafluoroethylene and reacted at 120 °C for 12 h. After natural cooling, the precipitate was collected by centrifugation, washed three times with water and three times with ethanol, and dried under vacuum at 60 °C to obtain ZIF-8@MXene material. S2. The ZIF-8@MXene material was ultrasonically dispersed in a reaction flask containing DMF. Nitrogen gas was introduced to purge air from the system. A star-shaped chain transfer agent, acrylamide, and 2-acrylamido-2-methylpropanesulfonic acid were added. Nitrogen gas was continued to be introduced and the temperature was raised to 70°C. The initiator was dissolved in DMF and then added dropwise to the reaction flask under nitrogen protection. After the addition was complete, the reaction was stirred for 8-12 hours. After the reaction was complete, THF was added for dilution, and then the mixture was poured into ice-cold ether, filtered, and the solid was dried to obtain the final product. S3. Disperse the solid from step S2 in an aqueous solution of sodium carboxymethyl cellulose, add N,N'-methylenebisacrylamide, sonicate for 2 hours to form a uniform slurry, inject the slurry into a cylindrical mold, pre-react at 50~60℃ for 4-6 hours to form a hydrogel, then freeze at -80℃ for 12 hours, and then transfer to a freeze dryer for freeze drying for 24 hours to obtain a lightweight porous composite aerogel.

2. The method for preparing functionalized cellulose composite aerogel for water treatment according to claim 1, characterized in that, The preparation process of MXene is as follows: LiF was dissolved in a 6-12 M HCl solution, and Ti3AlC2 powder was slowly added. The mixture was reacted at 30-40℃ for 18-36 h. After the reaction, the mixture was centrifuged and washed until the pH of the supernatant was 5-7. Finally, the mixture was ultrasonically exfoliated and centrifuged to obtain few-layer MXene.

3. The method for preparing functionalized cellulose composite aerogel for water treatment according to claim 1, characterized in that, In step S1, the mass ratio of MXene to Zn(NO3)2·6H2O is 1:1~5.

4. The method for preparing functionalized cellulose composite aerogel for water treatment according to claim 1, characterized in that, The preparation process of the star-shaped chain transfer agent is as follows: 1) Add 1 equivalent of dipentaerythritol to the reaction flask, place the reaction flask in an ice-water bath, and then add DMF dropwise under nitrogen protection. After the solid is completely dissolved, slowly add 6 equivalents of chloroacetyl chloride. Maintain the system temperature below 35°C and react for 2 hours. Then, control the temperature at 40°C and react overnight. Add deionized water to the reaction solution to precipitate a pale yellow solid. Filter, dry, and set aside. 2) Add the pale yellow solid from step 1) to a single-necked flask, add tetrahydrofuran (THF) and stir to dissolve it, then add a THF solution of dithiobenzoic acid dropwise. After the addition is complete, adjust the temperature in the reactor to 40°C and react for 10 hours. Filter, remove the solvent from the filtrate by rotary evaporation, add sodium hydroxide solution and wash repeatedly with distilled water, then dissolve in THF and distill under reduced pressure to obtain the final product.

5. The method for preparing functionalized cellulose composite aerogel for water treatment according to claim 1, characterized in that, In step S3, the molar ratio of acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, star chain transfer agent, and initiator is 500~700:300~500:5:0.1; the initiator is AIBN.

6. The method for preparing functionalized cellulose composite aerogel for water treatment according to claim 1, characterized in that, In step S3, the mass ratio of ZIF-8@MXene material to the total of acrylamide and 2-acrylamido-2-methylpropanesulfonic acid monomers is 1:5~20.

7. The method for preparing functionalized cellulose composite aerogel for water treatment according to claim 1, characterized in that, In step S3, the mass ratio of the solid to sodium carboxymethyl cellulose and N,N'-methylenebisacrylamide is 1:1~10:0.02~0.

05.

8. Functionalized cellulose composite aerogel for water treatment prepared by the method according to any one of claims 1-7.

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