Cellulose / chitosan / lanthanum oxide composite material for efficiently removing nitrogen and phosphorus in water body

Abstract

The invention discloses a cellulose / chitosan / lanthanum oxide composite material for efficiently removing nitrogen and phosphorus from a water body. The composite material is mainly prepared from the following raw materials: bacterial cellulose, chitosan, lanthanum nitrate hexahydrate and sodium hydroxide. By regulating and controlling the dosage of raw materials such as chitosan, lanthanum nitrate hexahydrate, sodium hydroxide and the like in the synthesis process of the material, the process parameters of material preparation are optimized, so that the optimal nitrogen and phosphorus removal performance is achieved. The practical application capability of the material is verified by evaluating the nitrogen and phosphorus removal performance, the application stability and the environmental factor influence of the material. The development of the material solves the problems that an environmental functional material is high in preparation cost, low in adsorption capacity, poor in selectivity and incapable of removing nitrogen and phosphorus at the same time. Theoretical support is provided for preparation of the nitrogen and phosphorus removal adsorption composite material for the water body, and meanwhile, the composite material has a wide practical application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of water treatment, and relates to a cellulose / chitosan / lanthanum oxide composite material and application thereof in synchronously removing nitrogen and phosphorus pollutants in water. Background Art

[0002] At present, the problem of eutrophication of water bodies is becoming increasingly prominent. With the discharge and enrichment of nutrients such as nitrogen and phosphorus, algal blooms frequently occur in lakes, seriously affecting the health of aquatic ecology. The key to solving the problem of eutrophication of lake water bodies is to reduce the content of nutrients such as nitrogen and phosphorus in the water body. At present, the widely used technologies for nitrogen and phosphorus removal in water bodies include biodegradation, chemical precipitation, adsorption and membrane filtration. Among them, adsorption has attracted much attention as an efficient and environmentally friendly nitrogen and phosphorus removal technology. However, traditional adsorption materials, which are the key to adsorption technology, often have problems such as high preparation cost, low adsorption capacity, poor selectivity, and inability to take into account both nitrogen and phosphorus removal. Therefore, there is an urgent need to prepare new adsorption materials with low cost, excellent performance, good selectivity, and efficient removal of nitrogen and phosphorus in water bodies.

[0003] Existing studies have shown that cellulose, as a natural polymer material, has attracted much attention in the field of water treatment due to its good renewability, biodegradability and rich hydroxyl functional groups on the surface. Studies have shown that the adsorption capacity of cellulose for nitrate and ammonia nitrogen can be effectively improved through modification methods such as etherification and amination. However, single cellulose materials often have problems such as low mechanical strength, easy swelling in water and poor selectivity for phosphate, which limits their practical application. Chitosan has excellent adsorption performance for heavy metals and organic pollutants through the amino and hydroxyl groups on the molecular chain, but it is easy to dissolve and inactivate in acidic environments, and the adsorption capacity for phosphate is low (<30mg / g), making it difficult to achieve simultaneous removal of nitrogen and phosphorus elements. In addition, the mass transfer efficiency of pure chitosan materials is low due to their low porosity and small specific surface area. Lanthanide compounds, such as La(OH) 3 ,La 2 O 3 Equivalent factors and PO 4 3- Formation of LaPO 4Precipitation, becoming an efficient phosphorus removal material. Studies have shown that the saturated adsorption capacity of nano-lanthanum oxide for phosphorus can reach 80-120 mg / g, but its nanoparticles are easy to agglomerate, difficult to achieve solid-liquid separation, and cannot remove nitrogen-containing pollutants when used alone. Therefore, it is necessary to solve the above problems through carrier immobilization technology. The cellulose / chitosan / lanthanum oxide composite material proposed in the present invention uses a three-dimensional cellulose network as a skeleton, which is beneficial to improving the mechanical strength of the material; the porosity is enhanced by chitosan cross-linking, which is beneficial to expose more active sites, and the amino functional groups on the surface of chitosan can target the adsorption of nitrate / ammonia nitrogen; lanthanum oxide can specifically capture phosphates, which is helpful to achieve the simultaneous removal of nitrogen and phosphorus. In addition, the cellulose / chitosan matrix can fix lanthanum oxide nanoparticles and inhibit their aggregation and loss. The cellulose / chitosan / lanthanum oxide composite material has certain practical application potential and provides a new idea for the preparation of environmentally friendly adsorption materials. Summary of the invention

[0004] The purpose of the present invention is to provide a preparation method and application of a cellulose / chitosan / lanthanum oxide composite material to achieve efficient removal of nitrogen and phosphorus elements in water.

[0005] The present invention adopts the following technical scheme: preparing a cellulose dispersion, ultrasonically dispersing, adding an acetic acid solution to the dispersion, adjusting the pH value of the solution, then weighing chitosan and immersing it in the solution, drying to constant weight, and obtaining a cellulose / chitosan composite material; then, in-situ depositing lanthanum hydroxide particles on the surface of the cellulose / chitosan composite material by using lanthanum nitrate hexahydrate, placing the generated cellulose / chitosan / lanthanum hydroxide in a reaction kettle, and finally obtaining a cellulose / chitosan / lanthanum oxide nanocomposite material.

[0006] The specific steps are as follows:

[0007] Step 1, taking a 10% by mass cellulose solution, placing it in an ice water bath, and ultrasonically dispersing it;

[0008] Step 2, weighing a certain amount of chitosan and dissolving it in a 1% by mass acetic acid solution, then adding it to the cellulose dispersion in step 1, adding 15% by mass glycerol, homogenizing and dispersing to obtain a cellulose / chitosan film liquid, and drying to obtain a cellulose / chitosan composite material;

[0009] Step 3, weighing the cellulose / chitosan composite material and lanthanum nitrate hexahydrate, dispersing them in 100 mL of deionized water, and ultrasonicating them for 30 minutes;

[0010] Step 4, then slowly adding sodium hydroxide solution to the solution in step 3, adjusting the pH of the solution, and stirring at 25° C. and 300 rpm for 4 hours;

[0011] Step 5, transferring the system obtained in step 4 to a 200 mL hydrothermal reactor, reacting at 135° C. in a nitrogen atmosphere for 10 h, cooling to room temperature after the reaction, washing and drying to obtain a cellulose / chitosan / lanthanum oxide nanocomposite material.

[0012] In step 2, the mass ratios of cellulose to chitosan are 1:0.2, 1:0.5, and 1:0.8.

[0013] In step 2, the amounts of chitosan used were 0.05, 0.1, and 0.15 g, respectively.

[0014] In step 3, the amounts of lanthanum nitrate hexahydrate used are 0.1 g, 0.15 g, and 0.2 g, respectively.

[0015] In step 4, the concentration of the sodium hydroxide solution is 0.01, 0.02, or 0.03 mol / L.

[0016] The present invention also includes a cellulose / chitosan / lanthanum oxide nanocomposite material prepared by a cellulose / chitosan / lanthanum oxide nanocomposite material preparation method.

[0017] In summary, this application includes the following beneficial technical effects:

[0018] (1) The method of the present invention is simple, convenient, low-cost, and requires mild reaction conditions.

[0019] (2) The cellulose / chitosan / lanthanum oxide nanocomposite prepared by the present invention has a higher adsorption capacity and can achieve targeted removal of nitrogen and phosphorus pollution in water bodies. Compared with traditional environmental functional materials, the cellulose / chitosan / lanthanum oxide nanocomposite has better stability and can maintain a higher adsorption capacity in complex environmental water bodies. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It's La 2 O 3 ,BC / La 2 O 3 ,BC / PDA and BC / CS / La 2 O 3 Adsorption capacity for nitrogen and phosphorus in water.

[0021] Figure 2 BC / CS / La prepared with different cellulose and chitosan mass ratios 2 O 3 Adsorption capacity for nitrogen and phosphorus in water.

[0022] Figure 3 BC / CS / La prepared with different CS dosages 2 O 3Adsorption capacity for nitrogen and phosphorus in water.

[0023] Figure 4 Is different La (NO 3 ) 3 6H 2 BC / CS / La prepared with O 2 O 3 Adsorption capacity for nitrogen and phosphorus in water.

[0024] Figure 5 BC / CS / La prepared with different NaOH dosages 2 O 3 Adsorption capacity for nitrogen and phosphorus in water.

[0025] Figure 6 It is BC / CS / La 2 O 3 -1The adsorption capacity of nitrogen and phosphorus in water under different pH environments.

[0026] Figure 7 It is BC / CS / La 2 O 3 -1The adsorption capacity of nitrogen and phosphorus in actual water bodies. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below with reference to the embodiments and comparative examples.

[0028] The present invention provides a cellulose / chitosan / lanthanum oxide composite material, wherein the cellulose is bacterial cellulose as an example, and comprises the following steps:

[0029] Step 1, weigh a certain amount of bacterial cellulose, prepare a BC solution with a mass fraction of 10%, place it in an ice water bath, and ultrasonically disperse it for 30 minutes.

[0030] Step 2, weigh a certain amount of chitosan (the mass ratio of cellulose to chitosan is 1:0.5) and dissolve it in a 1% acetic acid solution, then add it to the solution in step 1, add 15% glycerol, homogenize and disperse, and ultrasonically degas for 10 minutes to obtain a BC / CS membrane.

[0031] Step 3: weigh the BC / CS composite material and La(NO 3 ) 3 6H 2 O was dispersed in 100 mL of deionized water and ultrasonicated for 30 min.

[0032] Step 4: Then, slowly add NaOH solution to the solution in step 3, adjust the pH of the solution to 10, and stir at 25° C. and 300 rpm for 4 h.

[0033] Step 5, transferring the system obtained in step 4 to a 200 mL hydrothermal reactor, reacting at 135° C. for 10 h, cooling to room temperature after the reaction, washing with deionized water and anhydrous ethanol in turn and drying to obtain a cellulose / chitosan / lanthanum oxide nanocomposite material.

[0034] In step 2, the mass ratio of BC to CS is 1:0.2, 1:0.5, 1:0.8.

[0035] In step 2, the amounts of CS used are 0.05, 0.1, and 0.15 g, respectively.

[0036] In step 3, the La(NO 3 ) 3 6H 2 The dosage of O is 0.1, 0.15, and 0.2g.

[0037] In step 4, the concentrations of NaOH are 0.01, 0.02, and 0.03 mol / L, respectively.

[0038] BC / CS composite materials were prepared by combining bacterial cellulose with chitosan. A 10% BC solution was prepared and placed in an ice-water bath for ultrasonic dispersion for 30 min. Then, the weighed (0.05, 0.1, 0.15 g) CS was immersed in a 1% acetic acid solution, added to the BC dispersion, and 15% glycerol was added. The mixture was homogenized and degassed for 10 min to obtain a BC / CS composite material. Subsequently, 0.5 g BC / CS composite material and a certain amount of (0.1, 0.15, 0.2 g) La(NO 3 ) 3 6H 2 O was dispersed in 100 mL of deionized water and ultrasonicated for 30 min. Then, 50 mL of NaOH (0.01, 0.02, 0.03 mol / L) was slowly added at 25 °C and 300 rpm to adjust the pH of the solution to 10. Subsequently, the above reaction system was transferred to a 200 mL hydrothermal reactor and reacted at 135 °C for 10 h. After the reaction was completed, it was naturally cooled to room temperature, centrifuged at 900 rpm for 10 min to collect the product, and washed with deionized water and anhydrous ethanol in turn. Finally, it was dried in a vacuum drying oven at 90 °C for 6–8 h to obtain BC / CS / La. 2 O 3 Nanocomposite materials.

[0039] BC / CS / La 2 O 3 Nanocomposite materials Composite materials Nitrogen and phosphorus removal performance implementation plan

[0040] Step 1, prepare 100 mL of a mixed solution with a total nitrogen concentration of 50 mg / L (3.6 mg potassium nitrate) and a total phosphorus concentration of 10 mg / L (0.4 mg potassium dihydrogen phosphate).

[0041] Step 2, weigh 10 mg BC / CS / La 2 O 3 The composite material is added to the mixed solution, and the pH value is adjusted to 7.0 using hydrochloric acid and sodium hydroxide.

[0042] Step 3, placing the above solution in a constant temperature shaking box, shaking and adsorbing at 25°C at a speed of 150 rpm.

[0043] Step 4: After adsorption, BC / CS / La 2 O 3 The composite material was taken out from the solution, ultrasonically desorbed in a methanol solution containing 0.02 mol / L NaOH, then washed multiple times in ethanol and pure water, and freeze-dried for later use.

[0044] In step 1, it is selected whether to add inorganic anions and dissolved organic matter.

[0045] In step 2, the pH value of the solution can be selected from 5.0, 6.0, 7.0, and 8.0.

[0046] The following provides examples of specific data of the present invention

[0047] Embodiment 1,

[0048] Step 1, weigh BC, prepare a BC solution with a mass fraction of 10%, place it in an ice water bath, and ultrasonically disperse it for 30 minutes.

[0049] Step 2, weigh 0.1g chitosan (the mass ratio of cellulose to chitosan is 1:0.5) and dissolve it in 1% acetic acid solution, then add it to the solution in step 1, add 15% glycerol, homogenize and disperse, and ultrasonically degas for 10 minutes to obtain a BC / CS membrane.

[0050] Step 3: weigh BC / CS composite material and 0.15 g La(NO 3 ) 3 6H 2 O was dispersed in 100 mL of deionized water and ultrasonicated for 30 min.

[0051] Step 4: Then, NaOH (40 mL 1.5 mol / L) solution was slowly added to the solution in step 3 to adjust the pH of the solution to 10, and stirred at 25° C. and 300 rpm for 4 h.

[0052] Step 5: Transfer the system obtained in step 4 to a 200 mL hydrothermal reactor and react at 135°C for 10 h. After the reaction is completed, cool to room temperature, wash with deionized water and anhydrous ethanol in turn, and dry to obtain a cellulose / chitosan / lanthanum oxide nanocomposite material. Named BC / CS / La 2 O 3 -1.

[0053] The following provides a comparative example of the specific data of the present invention

[0054] Comparative Example 1,

[0055] Step 1 and step 2 are consistent with step 1 and step 2 in the embodiment. The obtained material is named BC / CS.

[0056] Comparative Example 2,

[0057] Step 1 is the same as Step 1 in Example 1.

[0058] Step 2, weigh 0.15 g La(NO 3 ) 3 6H 2 O was dissolved in 100 mL of deionized water to prepare lanthanum nitrate solution.

[0059] Step 3, slowly add the prepared BC dispersion to the lanthanum nitrate solution, stir evenly, move the above system to a 200mL hydrothermal reactor, and react at 100°C for 18h: After the reaction is completed, cool to room temperature, wash with anhydrous ethanol three times, and dry to obtain BC / La 2 O 3

[0060] Comparative Example 3,

[0061] Step 1 is the same as Step 1 in Example 1.

[0062] Step 2, weigh 0.1g chitosan (the mass ratio of cellulose to chitosan is 1:0.2) and dissolve it in 1% acetic acid solution, then add it to the solution in step 1, add 15% glycerol, homogenize and disperse, and ultrasonically degas for 10 minutes to obtain a BC / CS membrane.

[0063] Step 3, step 4, step 5 are the same as step 3, step 4, step 5 in the embodiment. The obtained material is named BC / CS / La 2 O 3 -2

[0064] Comparative Example 4,

[0065] Step 1 is the same as Step 1 in Example 1.

[0066] Step 2, weigh 0.1g chitosan (the mass ratio of cellulose to chitosan is 1:0.8) and dissolve it in 1% acetic acid solution, then add it to the solution in step 1, add 15% glycerol, homogenize and disperse, and ultrasonically degas for 10 minutes to obtain a BC / CS membrane.

[0067] Step 3, step 4, step 5 are the same as step 3, step 4, step 5 in the embodiment. The obtained material is named BC / CS / La 2 O 3 -3

[0068] Comparative Example 5,

[0069] Step 1 is the same as Step 1 in Example 1.

[0070] Step 2, weigh 0.05g chitosan (the mass ratio of cellulose to chitosan is 1:0.5) and dissolve it in 1% acetic acid solution, then add it to the solution in step 1, add 15% glycerol, homogenize and disperse, and ultrasonically degas for 10 minutes to obtain a BC / CS membrane.

[0071] Step 3, step 4, step 5 are the same as step 3, step 4, step 5 in the embodiment. The obtained material is named BC / CS / La 2 O 3 -4

[0072] Comparative Example 6,

[0073] Step 1 is the same as Step 1 in Example 1.

[0074] Step 2, weigh 0.15g chitosan (the mass ratio of cellulose to chitosan is 1:0.5) and dissolve it in 1% acetic acid solution, then add it to the solution in step 1, add 15% glycerol, homogenize and disperse, and ultrasonically degas for 10 minutes to obtain a BC / CS membrane.

[0075] Step 3, step 4, step 5 are the same as step 3, step 4, step 5 in the embodiment. The obtained material is named BC / CS / La 2 O 3 -5

[0076] Comparative Example 7,

[0077] Step 1 and step 2 are consistent with step 1 and step 2 in the embodiment.

[0078] Step 3: weigh BC / CS composite material and 0.1 g La(NO 3 ) 3 6H 2 O was dispersed in 100 mL of deionized water and ultrasonicated for 30 min.

[0079] Step 4, step 4 is consistent with step 5, step 5 in the embodiment. The obtained material is named BC / CS / La 2 O 3 -6

[0080] Comparative Example 8,

[0081] Step 1 and step 2 are consistent with step 1 and step 2 in the embodiment.

[0082] Step 3: weigh BC / CS composite material and 0.2 g La(NO 3 ) 3 6H 2 O was dispersed in 100 mL of deionized water and ultrasonicated for 30 min.

[0083] Step 4, step 4 is consistent with step 5, step 5 in the embodiment. The obtained material is named BC / CS / La 2 O 3 -7

[0084] Comparative Example 9,

[0085] Step 1, step 2, step 3 are the same as step 1, step 2, step 3 in Example 1

[0086] Step 4: Slowly add 0.01 mol / L NaOH solution to the solution in step 3, adjust the pH of the solution to 10, and stir at 25° C. and 300 rpm for 4 h.

[0087] Step 5 is the same as step 5 in the embodiment. 2 O 3 The prepared material is named BC / CS / La 2 O 3 -8

[0088] Comparative Example 10,

[0089] Step 1, step 2, step 3 are the same as step 1, step 2, step 3 in Example 1

[0090] Step 4: Slowly add 0.03 mol / L NaOH solution to the solution in step 3, adjust the pH of the solution to 10, and stir at 25° C. and 300 rpm for 4 h.

[0091] Step 5 is the same as step 5 in the embodiment. 2 O 3 The prepared material is named BC / CS / La 2 O 3 -9

[0092] The following provides an application example of specific data of the present invention

[0093] Application Example 1:

[0094] Step 1, prepare 100 mL of a mixed solution with a total nitrogen concentration of 50 mg / L (3.6 mg potassium nitrate) and a total phosphorus concentration of 10 mg / L (0.4 mg potassium dihydrogen phosphate).

[0095] Step 2, weigh 10 mg BC / CS / La 2 O 3 The composite material is added to the mixed solution, and the pH is adjusted to 5.0 using hydrochloric acid and sodium hydroxide.

[0096] Step 3, placing the above solution in a constant temperature shaking box, shaking and adsorbing at 25° C. at a rotation speed of 200 rpm.

[0097] Step 4: After adsorption, BC / CS / La 2 O 3 The composite material was taken out from the solution, ultrasonically desorbed in a methanol solution containing 0.1 mol / L NaOH, then washed multiple times in ethanol and pure water, and freeze-dried for later use.

[0098] Application Example 2:

[0099] Step 1 is the same as step 1 in Application Example 1.

[0100] Step 2, weigh 10 mg BC / CS / La 2 O 3 The composite material is added to the mixed solution, and the pH is adjusted to 5.0 using hydrochloric acid and sodium hydroxide.

[0101] Step 3 and step 4 are the same as step 3 and step 4 in application example 1.

[0102] Application Example 3:

[0103] Step 1 is the same as step 1 in Application Example 1.

[0104] Step 2, weigh 10 mg BC / CS / La 2 O 3 The composite material is added into the mixed solution, and the pH value is adjusted to 6.0 by using hydrochloric acid and sodium hydroxide.

[0105] Step 3 and step 4 are the same as step 3 and step 4 in application example 1.

[0106] Application example 4,

[0107] Step 1 is the same as step 1 in Application Example 1.

[0108] Step 2, weigh 10 mg BC / CS / La 2 O 3 The composite material is added to the mixed solution, and the pH value is adjusted to 7.0 using hydrochloric acid and sodium hydroxide.

[0109] Step 3 and step 4 are the same as step 3 and step 4 in application example 1.

[0110] Application Example 5:

[0111] Step 1 is the same as step 1 in Application Example 1.

[0112] Step 2, weigh 10 mg BC / CS / La 2 O 3 The composite material is added into the mixed solution, and the pH value is adjusted to 8.0 by using hydrochloric acid and sodium hydroxide.

[0113] Step 3 and step 4 are the same as step 3 and step 4 in application example 1.

[0114] Application Example 6:

[0115] Step 1, take 100 mL of Wuxi Taihu Lake water, filter it with a 0.22 μm filter membrane, and then add 50 mg / L of a mixed solution of inorganic nitrogen and inorganic phosphorus.

[0116] Step 2, weigh 10 mg BC / CS / La 2 O 3 The composite material was added into the actual water sample and the pH was adjusted to 5.0 using hydrochloric acid and sodium hydroxide.

[0117] Step 3 and step 4 are the same as step 3 and step 4 in application example 1.

[0118] Combination Figure 1 It can be seen that the nitrogen and phosphorus adsorption capacities of the comparative sample BC are 65.7 mg / g and 0 mg / g respectively; the nitrogen and phosphorus adsorption capacities of BC / CS are 105.6 mg / g and 79.4 mg / g respectively; 2 O 3 The nitrogen and phosphorus adsorption capacities of BC / CS / La were 87.2 mg / g and 92.4 mg / g, respectively. 2 O 3 The nitrogen and phosphorus adsorption capacities of the materials are increased to 135.2 mg / g and 156.3 mg / g respectively. This proves that the adsorption capacity of the materials designed in this patent is higher than that of single materials or other related materials.

[0119] Combination Figure 2 It can be seen that different mass ratios of cellulose and chitosan will affect BC / CS / La 2 O 3The nitrogen and phosphorus adsorption capacity of the composite material increased first and then decreased with the decrease of the mass ratio, and the optimal mass ratio was 1:0.5. Figure 3 It can be seen that the amount of CS will affect BC / CS / La 2 O 3 The nitrogen and phosphorus adsorption capacity of CS is 0.1g. Figure 4 It can be seen that La(NO 3 ) 3 6H 2 O dosage affects BC / CS / La 2 O 3 The nitrogen and phosphorus adsorption capacity of La(NO 3 ) 3 6H 2 As the amount of O increases, the adsorption capacity of the composite material for nitrogen and phosphorus increases. 3 ) 3 6H 2 When the amount of O reaches 0.15g, the adsorption capacity of the composite material for nitrogen and phosphorus reaches 135.2mg / g and 156.3mg / g respectively. Figure 5 It can be seen that the amount of NaOH will affect BC / CS / La 2 O 3 When the amount of NaOH reached 0.02 mol / L, the adsorption capacity of nitrogen and phosphorus of the composite material reached 135.2 mg / g and 156.3 mg / g respectively. 2 O 3 The optimal conditions were to control the mass ratio of cellulose to chitosan to 1:0.5, the amount of CS to 0.1 g, and the amount of La(NO 3 ) 3 6H 2 The amount of O used was 0.15 g, and the amount of NaOH was controlled to be 0.02 mol / L.

[0120] In the application example, combined with Figure 6 It can be seen that BC / CS / La 2 O 3 -1 composite material can maintain nitrogen and phosphorus adsorption capacities exceeding 130mg / g and 150mg / g respectively in a wide range of pH environments (5-8). Figure 7 It can be seen that the prepared BC / CS / La 2 O 3 The nitrogen and phosphorus adsorption capacities in actual water bodies are 128.4 mg / g and 147.5 mg / g, respectively, indicating that BC / CS / La 2 O 3 It has certain practical application potential.

[0121] From the above data, it can be seen that the cellulose / chitosan / lanthanum oxide composite material can efficiently remove nitrogen and phosphorus (nitrogen and phosphorus concentrations after treatment are below the detection limit). In summary, taking bacterial cellulose as an example, we provide a preparation method of cellulose / chitosan / lanthanum oxide composite materials and their application in nitrogen and phosphorus removal from water bodies. The results show that the composite material has excellent performance and good practical application prospects.

Claims

1. A method for preparing a cellulose / chitosan / lanthanum oxide nanocomposite material, characterized in that: The preparation method of the material is as follows: preparing a cellulose dispersion, ultrasonically dispersing, adding an acetic acid solution to the dispersion, adjusting the pH value of the solution, then weighing chitosan and immersing it in the above solution, drying to constant weight, and obtaining a cellulose / chitosan composite material; then, using lanthanum nitrate hexahydrate to in-situ deposit lanthanum hydroxide particles on the surface of the cellulose / chitosan composite material, placing the generated cellulose / chitosan / lanthanum hydroxide in a reaction kettle, and finally obtaining a cellulose / chitosan / lanthanum oxide nanocomposite material.

2. A method for preparing a cellulose / chitosan / lanthanum oxide nanocomposite material, characterized in that: The following steps are involved: Step 1, taking a 10% by mass cellulose solution, placing it in an ice water bath, and ultrasonically dispersing it; Step 2: weigh a certain amount of chitosan and dissolve it in a 1% acetic acid solution, then add it to the cellulose dispersion in step 1, add 15% glycerol, and disperse it homogeneously. A cellulose / chitosan film liquid is obtained, and a cellulose / chitosan composite material is obtained after drying; Step 3, weighing the cellulose / chitosan composite material and lanthanum nitrate hexahydrate, dispersing them in 100 mL of deionized water, and ultrasonicating them for 30 minutes; Step 4, then slowly adding sodium hydroxide solution to the solution in step 3, adjusting the pH of the solution, and stirring at 25° C. and 300 rpm for 4 hours; Step 5, transferring the system obtained in step 4 to a 200 mL hydrothermal reactor, reacting at 135° C. in a nitrogen atmosphere for 10 h, cooling to room temperature after the reaction, washing and drying to obtain a cellulose / chitosan / lanthanum oxide nanocomposite material.

3. The method for preparing the cellulose / chitosan / lanthanum oxide nanocomposite material according to claim 2, characterized in that: In step 2, the mass ratios of cellulose to chitosan are 1:0.2, 1:0.5, and 1:0.

8.

4. The method for preparing the cellulose / chitosan / lanthanum oxide nanocomposite material according to claim 2, characterized in that: In step 2, the amounts of chitosan used were 0.05, 0.1, and 0.15 g, respectively.

5. The method for preparing the cellulose / chitosan / lanthanum oxide nanocomposite material according to claim 2, characterized in that: In step 3, the amounts of lanthanum nitrate hexahydrate used are 0.1 g, 0.15 g, and 0.2 g, respectively.

6. The method for preparing the cellulose / chitosan / lanthanum oxide nanocomposite material according to claim 2, characterized in that: In step 4, the concentration of the sodium hydroxide solution is 0.01, 0.02, or 0.03 mol / L.

7. The cellulose / chitosan / lanthanum oxide nanocomposite material prepared by the method for preparing a cellulose / chitosan / lanthanum oxide nanocomposite material according to any one of claims 1 to 7.

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