Modified Tibetan fritillary bulb as well as preparation method and application thereof

Abstract

The invention relates to the technical field of environmental protection, and discloses a modified Tibetan fritillary bulb and a preparation method and application thereof.The modified Tibetan fritillary bulb is obtained by placing Tibetan fritillary bulb in a cellulase solution, breaking the cell wall structure of the Tibetan fritillary bulb with cellulase and retaining the fiber net structure, and reacting at the temperature of 50-55 DEG C for 20-22 min; the mass volume ratio of the Tibetan fritillary bulb to the cellulase solution is 10 g: 50 mL-55 mL; the concentration of the cellulase solution is 2.5 mg / mL to 3.8 mg / mL. The PM2.5 removal rate of the Tibetan fritillary bulb reaches up to 34.04%, and after the Tibetan fritillary bulb is recycled for seven times, the modified Tibetan fritillary bulb still has a certain adsorption effect.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental protection, and particularly relates to a modified Tibetan Fritillaria thunbergii and a preparation method and application thereof. Background Art

[0002] PM 2.5 There are two main sources of pollution: natural and man-made. Man-made pollution sources include fixed sources and mobile sources. Mobile sources are mainly exhaust gases emitted by various vehicles when using fuel during operation. The above sources have a relatively serious impact on the quality of outdoor air. Fixed sources refer to coal burning and heating generated in various industrial processes such as electricity, petrochemicals, textiles, printing and dyeing; incense in daily life; and smoke emitted during cooking using coal, gas or fuel. In summer, most families use mosquito coils to repel mosquitoes, and mosquito coils release a large amount of PM when burned. 2.5 , people are in indoor PM for a long time 2.5 Excessive levels can lead to a variety of diseases, such as respiratory diseases and cardiovascular diseases.

[0003] Currently used to remove PM from the air 2.5 There are many methods, such as using activated carbon to 2.5 However, the material is wood, which requires high temperature calcination and wastes resources. 2.5 This method is sensitive to the operating environment, has high technical requirements, and is relatively complex to operate. In addition, both of the above-mentioned adsorbents have 2.5 The problem of poor adsorption effect. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a modified Fritillaria tibetica and a preparation method and application thereof, wherein a dense fiber network structure is formed in the Fritillaria tibetica by cellulase, thereby effectively improving the PM 2.5 The adsorption effect is excellent and can be adsorbed multiple times.

[0005] To achieve the above objectives, the specific technical solutions of the present invention are as follows.

[0006] The first aspect of the present invention provides a modified Tibetan Fritillaria, wherein the modified Tibetan Fritillaria is obtained by placing the Tibetan Fritillaria in a cellulase solution, using cellulase to destroy the cell wall structure of the Tibetan Fritillaria and retaining the fiber network structure, and reacting at 50°C to 55°C for 20min to 22min;

[0007] The mass volume ratio of the Tibetan Fritillaria tibetana to the cellulase solution is 10 g: 50 mL to 55 mL;

[0008] The concentration of the cellulase solution is 2.5 mg / mL to 3.8 mg / mL.

[0009] The modified Fritillaria tibetica of the present invention has a significant effect on PM 2.5 It has a good adsorption effect. By using cellulase to modify the Tibetan Fritillaria, the content of C, H, N, and S elements in the modified Tibetan Fritillaria is increased, thereby effectively improving the adsorption effect. Compared with the 6.36% of activated carbon and 5.14% of macroporous adsorption resin in the prior art, the PM 2.5 Adsorption rate, modified Fritillaria tibetica PM in the present invention 2.5 The adsorption rate can reach 34.04%.

[0010] In another preferred embodiment, the particle size of the Tibetan Fritillaria is 40 mesh to 100 mesh.

[0011] In another preferred embodiment, the enzyme inactivation temperature is 70°C to 75°C and the time is 8 min to 10 min.

[0012] The second aspect of the present invention provides a method for preparing the modified Fritillaria tibetica, comprising the following steps:

[0013] Mixing the Fritillaria tibetana and the cellulase solution in a mass volume ratio of 10 g: 50 mL to 55 mL, reacting at 50° C. to 55° C. for 20 min to 22 min, and then inactivating the enzyme at 70° C. to 75° C. for 8 min to 10 min to obtain the Fritillaria tibetana after the enzyme is inactivated;

[0014] The enzyme-inactivated Fritillaria tibetica is rinsed to neutrality, dried, and crushed to obtain the modified Fritillaria tibetica;

[0015] The concentration of the cellulase solution is 2.5 mg / mL to 3.8 mg / mL.

[0016] The third aspect of the present invention provides the modified Fritillaria tibetica for preparing PM adsorption 2.5 application in products.

[0017] A fourth aspect of the present invention provides a PM 2.5 The modified Fritillaria tibetica is placed in a PM-containing 2.5 In the gas, the modified Fritillaria tibetica is used to treat PM 2.5 Adsorb to remove PM from the air 2.5 .

[0018] In another preferred embodiment, the adsorption time is 30 min to 150 min.

[0019] In another preferred embodiment, the adsorption temperature is 25°C to 28°C.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) The effect of the Fritillaria tibetica on PM 2.5 The removal rate is as high as 34.04%, and after seven cycles of use, the modified Fritillaria tibetica still has a certain adsorption effect. The present invention uses cellulase to modify the Fritillaria tibetica, which can destroy the original cell wall structure, retain a large number of dense fiber mesh structures, present a loose and porous form, and greatly enhance the adsorption capacity. 2.5 The removal rate can reach 34.04%.

[0022] (2) The present invention adjusts the concentration of the cellulase solution, the reaction temperature and the enzyme inactivation time to make the modified Fritillaria tibetica have good PM 2.5 Removal effect of 2g of modified Fritillaria tibetica on PM in a closed environment 2.5 Concentration: 500±5μg / m 3 , PM after adsorption for 30 minutes 2.5 The removal rate can reach 33.48%. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a single factor effect analysis diagram.

[0024] Figure 2 This is a graph showing the effects of cellulase concentration and enzyme inactivation temperature on removal rate.

[0025] Figure 3 The effect of NaOH concentration on PM adsorption by Fritillaria tibetica 2.5 Impact results diagram.

[0026] Figure 4 The effect of hemicellulase concentration on PM adsorption by Fritillaria tibetica 2.5 Impact results diagram.

[0027] Figure 5 is the effect of cellulase concentration on PM adsorption by Fritillaria tibetica 2.5 Impact results diagram.

[0028] Figure 6 is the effect of neutral protease concentration on PM adsorption by Fritillaria tibetica 2.5 Impact results diagram.

[0029] Figure 7 Modification of the particle size of Fritillaria tibetica for PM adsorption 2.5 Impact results diagram.

[0030] Figure 8 Effect of modified Fritillaria tibetica addition on PM adsorption 2.5 Impact results diagram.

[0031] Fig. 9 Effect of temperature on PM adsorption by modified Fritillaria tibetica2.5 Impact results diagram.

[0032] Fig.10 Effect of pollutant concentration on PM adsorption by modified Fritillaria tibetica 2.5 Impact results diagram.

[0033] Fig.11 The adsorption time of PM by modified Fritillaria tibetica 2.5 Impact results diagram.

[0034] Fig.12 The infrared spectra of modified Fritillaria tibetica under different conditions, a in the figure is PM 2.5 Tibetan Fritillaria after adsorption; b is the optimal modified Tibetan Fritillaria adsorbent; c is the original Tibetan Fritillaria.

[0035] Fig.13 These are scanning electron micrographs of modified Fritillaria tibetana under different conditions.

[0036] Fig.14 This is a curve of the adsorption amount changing with the adsorption temperature.

[0037] Fig.15 Fitting diagram of the adsorption thermodynamic equation.

[0038] Fig.16 For PM 2.5 The relationship between initial concentration and adsorption amount.

[0039] Fig.17 This is the Langmuir model fitting diagram.

[0040] Fig.18 This is the Freundlich model fitting diagram.

[0041] Fig.19 This is a graph showing the variation of adsorption amount with adsorption time.

[0042] Fig. 20 This is the fitting diagram of the pseudo-first-order kinetic equation.

[0043] Fig.21 This is the fitting diagram of the pseudo-second-order kinetic equation.

[0044] Fig. 22 Adsorb PM for different materials 2.5 Comparison chart.

[0045] Fig.23 This is the adsorption frequency result graph of modified Fritillaria tibetica. DETAILED DESCRIPTION

[0046] The following will be combined with the specific embodiments of the present invention to clearly and completely describe the technical solutions in the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] The methods described in the embodiments of the present invention are conventional methods unless otherwise specified. The materials, reagents, etc. used can be obtained from commercial sources unless otherwise specified.

[0048] In the prior art, activated carbon or macroporous adsorption resin is usually used to adsorb PM 2.5 However, the adsorption effect is not ideal.

[0049] Tibetan Fritillaria is a kind of traditional Chinese medicine Fritillaria, which contains multiple proven active ingredients and a large amount of alkaloids, and has the effects of clearing heat and moistening the lungs, anti-inflammatory and sterilization, and anti-oxidation. The present invention uses Tibetan Fritillaria as a raw material and obtains a highly efficient PM purification product through cellulase modification. 2.5 Modified Fritillaria tibetica and its effects on PM 2.5 The adsorption effect is much higher than that of activated carbon and macroporous adsorption resin in the prior art.

[0050] In the following examples, the Fritillaria tibetica was collected from the Tibetan Plateau, and its bulbs were used.

[0051] Hemicellulase, neutral protease and cellulase were purchased from Nanning Pangbo Bioengineering Co., Ltd.; AB-8 macroporous adsorption resin (analytical grade) was purchased from Donghong Chemical Co., Ltd.; activated carbon (analytical grade) and diatomaceous earth (analytical grade) were purchased from Tianjin Ruijinte Chemical Co., Ltd., and bamboo charcoal was purchased from Tianjin Likang Environmental Protection Technology Co., Ltd.

[0052] Example 1

[0053] A method for preparing modified Fritillaria tibetica comprises the following steps:

[0054] S1. Mix the Fritillaria tibetana and the cellulase solution in a mass volume ratio of 10 g:50 mL, and bathe the mixture in a water bath at a constant temperature of 50° C. for 20 min to obtain the enzyme-treated Fritillaria tibetana; wherein the concentration of the cellulase solution is 2.5 mg / mL.

[0055] S2. Place the enzyme-treated Fritillaria tibetana in a water bath at a constant temperature of 70° C. for 10 minutes to inactivate the cellulase, thereby obtaining the enzyme-inactivated Fritillaria tibetana.

[0056] S3. Rinse the enzyme-inactivated Fritillaria tibetica with distilled water until the pH is 7, put it into an oven, dry it at 80° C. for 5 hours, and then grind it to obtain a modified Fritillaria tibetica with a particle size of 40 mesh.

[0057] Example 2

[0058] A method for preparing a modified Tibetan Fritillaria thunbergii comprises the following steps:

[0059] S1. Mix the Fritillaria tibetana and the cellulase solution in a mass volume ratio of 10 g:55 mL, and bathe in a water bath at a constant temperature of 55° C. for 22 min to obtain the enzyme-treated Fritillaria tibetana; wherein the concentration of the cellulase solution is 3 mg / mL.

[0060] S2. Place the enzyme-treated Fritillaria tibetana in a water bath at a constant temperature of 75° C. for 8 minutes to inactivate the cellulase, thereby obtaining the enzyme-inactivated Fritillaria tibetana.

[0061] S3. Rinse the enzyme-inactivated Fritillaria tibetica with distilled water until the pH is 7, put it into an oven, dry it at 80° C. for 5 hours, and then grind it to obtain a modified Fritillaria tibetica with a particle size of 40 mesh.

[0062] Example 3

[0063] A method for preparing a modified Tibetan Fritillaria thunbergii comprises the following steps:

[0064] S1. Mix the Tibetan Fritillaria and the cellulase solution in a mass volume ratio of 10 g:50 mL, and bathe in a water bath at a constant temperature of 50° C. for 20 min to obtain the enzyme-treated Tibetan Fritillaria; wherein the concentration of the cellulase solution is 3.8 mg / mL.

[0065] S2. Place the enzyme-treated Fritillaria tibetana in a water bath at a constant temperature of 75° C. for 10 minutes to inactivate the cellulase, thereby obtaining the enzyme-inactivated Fritillaria tibetana.

[0066] S3. Rinse the enzyme-inactivated Fritillaria tibetica with distilled water until the pH is 7, put it into an oven, dry it at 80° C. for 5 hours, and then grind it to obtain a modified Fritillaria tibetica with a particle size of 40 mesh.

[0067] In order to further illustrate the adsorption effect of the modified Tibetan Fritillaria in the present invention, the following experiments were conducted.

[0068] 1. Optimization of preparation conditions of modified Fritillaria tibetica

[0069] PM in the following 2.5 It refers to burning mosquito coils in a closed box to simulate the main pollutants in the atmosphere.

[0070] Three key factors affecting the removal rate of Tibetan Fritillaria: the concentration of cellulase solution, enzymatic hydrolysis temperature, and enzyme inactivation temperature. The optimal adsorption conditions of each influencing factor obtained in the above optimal method selection experiment were set to zero level, and the factor level coding table in Table 1 was compiled.

[0071] Table 1PM 2.5 Factor level coding table

[0072] Horizontal Code Value A: Cellulase concentration (mol / L) B: Enzymatic hydrolysis temperature (℃) C: enzyme inactivation temperature (℃) -1.682 2.2 42 62 -1 2.5 45 65 0 3.0 50 70 1 3.5 55 75 1.682 3.8 58 78 Horizontal interval value 0.5 5 5

[0073] Using DPS software, according to the three-factor five-level coding table, a quadratic orthogonal rotation regression was obtained for the study, as shown in Table 2. Referring to the factor level coding table, 23 modified Fritillaria tibetica were prepared, and the effects of the 23 modified Fritillaria tibetica on PM were studied. 2.5 The removal rate was calculated.

[0074] Table 2PM 2.5 Three-factor quadratic regression orthogonal rotation combination design table

[0075]

[0076]

[0077] Three main factors affecting the adsorption effect in the cellulase treatment experiment were selected: cellulase concentration X1, enzymatic hydrolysis temperature X2, and enzyme inactivation temperature X3. A total of 23 experiments were conducted, and the results of the first-order variance analysis shown in Table 3 were obtained based on the experimental results.

[0078] Table 3 ANOVA table

[0079] Sources of variation SS df MS F P <![CDATA[X1]]> 20.1994 1 20.1994 9.5886 0.0085 <![CDATA[X2]]> 24.5119 1 24.5119 11.6357 0.0046 <![CDATA[X3]]> 0.1330 1 0.133 0.0631 0.8055 <![CDATA[X 12 ]]> 107.639 1 107.639 51.0957 0.0001 <![CDATA[X 22 ]]> 74.2232 1 74.2232 35.2334 0.0001 <![CDATA[X 32 ]]> 5.9999 1 5.9999 2.8481 0.1153 <![CDATA[X1X2]]> 0.2145 1 0.2145 0.1018 0.7547 <![CDATA[X1X3]]> 8.7153 1 8.7153 4.1371 0.0629 <![CDATA[X2X3]]> 0.9316 1 0.9316 0.4422 0.5177 return 244.4652 9 27.1628 F2＝12.894 0.0003 Remaining 27.3860 13 2.1066 - - Lack of Fit 19.0424 5 3.8085 F1＝3.652 0.0277 error 8.3436 8 1.0429 - - sum 271.8512 22 - - -

[0080] Note: SS stands for the sum of squares of deviations, df stands for degrees of freedom, MS stands for mean square, F stands for the ratio of the mean square between groups to the mean square within groups, P stands for significant difference, - stands for the exclusion of the item, and the meanings in the following tables are the same.

[0081] From the analysis table data, we can see that X2 is significant at the 5% level, and X1X2 is extremely significant at the 1% level.

[0082] 1) Model establishment and verification: The data was analyzed using DPS data processing software, and the mathematical model regression equation of the three factors X1, X2, X3 and the removal rate Y was obtained as follows:

[0083] Y=19.19638+1.21617X1+1.33972X2+0.09868X3+2.62206X 12 +2.18365X 22 +0.6

[0084] 4747X 32 -0.16375X1X2 + 1.04375X1X3 - 0.34125X2X3。

[0085] At the α = 0.01 level, in the model, F1 = 3.652 < F0.01(5,8) = 6.63, indicating that the experimental error is very small and all unknown factors have been taken into account in the experimental design; F2 = 12.894 > F0.01(9,13) = 4.19, indicating that the regression equation is highly significant, the reliability of the experimental speculation is extremely high, the prediction is accurate, and the model is established.

[0086] 2) Quadratic variance analysis table: Conduct a significance test on the above regression. After removing the insignificant terms at the α = 0.10 level, the simplified regression equation is:

[0087] Y = 19.19638 + 1.21617X1 + 1.33972X2 + 2.62206X 12 + 2.18365X 22 + 1.04375X1X3。

[0088] The quadratic variance analysis is shown in Table 4.

[0089] Table 4 Quadratic variance analysis table

[0090] Sources of variation SS df MS F P <![CDATA[X1]]> 20.1994 1 20.1994 9.5886 0.0085 <![CDATA[X2]]> 24.5119 1 24.5119 11.6357 0.0046 <![CDATA[X 12 ]]> 107.6390 1 107.639 51.0957 0.0001 <![CDATA[X 22 ]]> 74.2232 1 74.2232 35.2334 0.0001 <![CDATA[X1X3]]> 8.7153 1 8.7153 4.1371 0.0629 return 244.4652 9 27.1628 F2＝12.894 0.0003 Remaining 27.3860 13 2.1066 - - Lack of Fit 19.0424 5 3.8085 F1＝3.652 0.0277 error 8.3436 8 1.0429 - - sum 271.8512 22 - - -

[0091] 3) Factor effect analysis

[0092] Single factor effect: When exploring the influence of a single factor on the experimental results, set other factors to the zero level. The results are shown in Table 5 and Figure 1 as shown.

[0093] Table 5 Removal rate after single factor effect

[0094] level <![CDATA[X1(%)]]> <![CDATA[X2(%)]]> <![CDATA[X3(%) <!-- 6 -->]]> -1.682 24.567 23.120 19.196 -1.341 22.280 21.326 19.196 -1 20.602 20.040 19.196 -0.5 19.244 19.072 19.196 0 19.196 19.196 19.196 0.5 20.460 20.412 19.196 1 23.035 22.720 19.196 1.341 25.542 24.919 19.196 1.682 28.658 27.626 19.196

[0095] From Figure 1 it can be seen that among them, X1 represents the concentration of cellulase, the removal rate first decreases and then increases with the increase of cellulase concentration, and the highest removal rate can reach 28.658%; X2 represents the reaction temperature, and the removal rate first decreases and then increases with the increase of enzymatic hydrolysis temperature, and the highest removal rate reaches 27.626%.

[0096] 5) Two-factor interaction effect

[0097] It can be seen from the simplified regression equation that the interaction of X1X3 is significant. Therefore, when studying the influence of cellulase concentration and enzyme inactivation temperature on the adsorption effect, the remaining factors need to be set to the zero level. The results are shown in Table 6 below.

[0098] Table 6 Removal rate of cellulose concentration and enzyme inactivation temperature

[0099]

[0100]

[0101] From the analysis of Table 6, it can be seen that when the enzyme inactivation temperature is constant, if the cellulase concentration increases, the adsorption capacity of the modified Fritillaria tibetica will first decrease and then increase; when the cellulase concentration is fixed, the adsorption capacity of the modified Fritillaria tibetica will first increase and then decrease with the increase of ultrasonic temperature. Figure 2 It can be seen that when the cellulase concentration is 3.8 mg / ml and the enzyme inactivation temperature is 78°C, the maximum removal rate is 31.6102%.

[0102] The DPS data processing system was used to obtain the adsorption of PM 2.5 Among the three factors, the best adsorption combination is (1.682, 1.682, 1.682), that is, the cellulase concentration is 3.8 mg / ml, the enzymatic hydrolysis temperature is 58°C, and the enzyme inactivation temperature is 78°C. At this time, the removal rate reaches the highest value of 34.04%. According to this combination, the optimal modified Fritillaria tibetica was prepared, and the adsorption of PM by the modified Fritillaria tibetica residue was tested. 2.5 The removal rate was 33.47% after three experiments. The actual measured value / software predicted value was 0.983, which was close to 1, indicating that the results were reliable and the model was correct.

[0103] 2. Adsorption effect of different enzyme-modified Fritillaria thunbergii

[0104] 1) Alkali blanching

[0105] Take 10g of Tibetan Fritillaria and divide it into five equal parts. Place the five parts of Tibetan Fritillaria in sodium hydroxide solutions with concentrations of 0.1mol / L, 0.2mol / L, 0.3mol / L, 0.4mol / L and 0.5mol / L, respectively, and bathe them in a water bath at 60℃ for 30min. Rinse the Tibetan Fritillaria after water bath with distilled water until the pH value is 7; after rinsing, place them in an oven at 80℃ to dry for 5h, crush and sieve to obtain 40-mesh modified Tibetan Fritillaria treated with alkali blanching.

[0106] 2) Hemicellulase treatment

[0107] Take 10g of Tibetan Fritillaria and divide it into five equal parts. Place the five parts of Tibetan Fritillaria in hemicellulase solutions with concentrations of 1mg / mL, 2mg / mL, 3mg / mL, 4mg / mL, and 5mg / mL, respectively, and bathe them in a water bath at 60℃ for 30min. Rinse the Tibetan Fritillaria after the water bath with distilled water until the pH is 7; after rinsing, place them in an oven at 80℃ to dry for 5h, crush and sieve to obtain 40-mesh hemicellulase-treated modified Tibetan Fritillaria.

[0108] 3) Cellulase treatment

[0109] Take 10g of Tibetan Fritillaria and divide it into five equal parts. Place the five parts of Tibetan Fritillaria in cellulase solutions with concentrations of 1mg / mL, 2mg / mL, 3mg / mL, 4mg / mL, and 5mg / mL, respectively, and bathe them in a water bath at 60℃ for 30min. Rinse the Tibetan Fritillaria after the water bath with distilled water until the pH is 7; after rinsing, place them in an oven at 80℃ to dry for 5h, crush and sieve to obtain 40-mesh cellulase-treated modified Tibetan Fritillaria.

[0110] 4) Neutral protease treatment

[0111] Take 10g of Tibetan Fritillaria and divide it into five equal parts. Place the five parts of Tibetan Fritillaria in neutral protease solutions with concentrations of 1mg / mL, 2mg / mL, 3mg / mL, 4mg / mL and 5mg / mL respectively; bathe in a water bath at 60℃ for 30min, rinse the Tibetan Fritillaria after the water bath with distilled water to a pH of 7; dry in an oven at 80℃ for 5h after rinsing, crush and sieve to obtain modified Tibetan Fritillaria treated with 40-mesh neutral protease.

[0112] Weigh 2 g of the modified Fritillaria tibetica obtained by the above different treatment methods and put them into PM 2.5 Concentration: 500±5μg / m 3 In a closed box, record the readings of the air quality detector after 30 minutes, calculate the removal rate of each, repeat the experiment and take the average value. The results are as follows Figure 3 to Figure 6 shown.

[0113] from Figure 3 to Figure 6 It can be seen that under the same experimental conditions, the modified Tibetan Fritillaria thunbergii obtained by the four pretreatment methods adsorbed PM 2.5 The effects of the modified Fritillaria tibetica obtained by cellulase treatment are as follows: cellulase treatment > alkaline blanching treatment > hemicellulase treatment > neutral protease treatment. 2.5 The removal rate and adsorption effect are the best.

[0114] 3. PM 2.5 Removal rate analysis

[0115] Impact on PM 2.5 The removal rate of PM2.5 was affected by many factors, including the particle size of modified Fritillaria tibetica, the amount of addition, the ambient temperature, the adsorption time, and the concentration of the pollutants. 2.5 Adsorption experiment.

[0116] 1) Effect of different modified Fritillaria tibetica particle sizes on PM 2.5 Effect of adsorption

[0117] The modified Fritillaria tibetica obtained by the above optimal method, i.e., the cellulase concentration was 3.8 mg / ml, the enzymolysis temperature was 58°C, and the enzyme inactivation temperature was 78°C, was sieved through 18 mesh, 40 mesh, 60 mesh, 80 mesh, and 100 mesh sieves respectively to obtain 5 modified Fritillaria tibetica with different particle sizes. 2 g of the modified Fritillaria tibetica with each particle size was weighed and the PM 2.5 The initial concentration was 500 ± 5 μg / m 3 After 30 min of adsorption, PM 2.5 The detector measures the PM in the closed box after adsorption 2.5 Concentration. Record various data before and after adsorption and calculate the removal rate. The results are as follows: Figure 7 As shown. Figure 7 It can be seen that the adsorption capacity of modified Tibetan Fritillaria increases first and then decreases with the increase of particle size, F=99.471, P<0.01. In the change from 18 mesh to 40 mesh, the adsorption effect increases with the increase of mesh number. When the mesh number reaches 40 mesh, the removal rate is the highest, but when the particle size is smaller than 40 mesh, the removal rate begins to decrease, so the optimal particle size is 40 mesh, and the removal rate is 32.29%.

[0118] 2) Effect of different addition amounts on PM 2.5 Effect of adsorption

[0119] Weigh 1g, 1.5g, 2g, 2.5g, and 3g of cellulase-treated modified Fritillaria tibetana with a mesh size of 40, and set the initial concentration of PM2.5 in the closed box to 500±5μg / m 3 , put different masses of modified Fritillaria tibetica into a closed box, and after adsorption for 30 minutes, use a PM2.5 detector to measure the PM2.5 concentration in the closed box after adsorption. Record the data before and after adsorption, and calculate the removal rate. The results are as follows Figure 8 shown.

[0120] from Figure 8 It can be seen that the adsorption capacity of modified Tibetan Fritillaria shows an increasing trend with the increase of the added amount, F=125.963, P<0.01. In the change from 1g to 3g, the adsorption effect increases with the increase of the added amount. When the mesh size reaches 3g, the removal rate is the highest, but the removal rates of 2g, 2.5g and 3g are not much different. Therefore, considering all factors, the optimal addition amount is 2g with a removal rate of 33.48%.

[0121] 3) Effect of different adsorption temperatures on PM2.5 adsorption

[0122] When the temperature in the sealed box is 19℃, 21℃, 23℃, 25℃, and 28℃, respectively, the PM in the sealed box is set 2.5 The initial concentration was 500 ± 5 μg / m 32 g of 40-mesh Tibetan Fritillaria residue treated with cellulase was added and adsorbed for 30 min. 2.5 The detector measures the PM in the closed box after adsorption. 2.5 Concentration. Record various data before and after adsorption and calculate the removal rate. The results are as follows: Fig. 9 shown.

[0123] from Fig. 9 It can be seen that the adsorption capacity of Tibetan Fritillaria shows an increasing trend with the increase of adsorption temperature, F=1529.141, P<0.01. In the change from 19℃ to 28℃, the adsorption effect increases with the increase of adsorption temperature. When it reaches 28℃, the removal rate is the highest, which is 33.37%.

[0124] 4) Effects of different pollutant concentrations on PM 2.5 Effect of adsorption

[0125] When PM in the closed box 2.5 The concentrations were 400±5μg / m 3 450±5μg / m 3 , 500±5μg / m 3 , 550±5μg / m 3 、600±5μg / m 3 2g of 40-mesh modified Fritillaria tibetana treated with cellulase was added, and the adsorption lasted for 30min. 2.5 The detector measures the PM in the closed box after adsorption. 2.5 Concentration. Record various data before and after adsorption and calculate the removal rate. The results are as follows: Fig.10 shown.

[0126] from Fig.10 It can be seen that the adsorption capacity of modified Fritillaria tibetica increases with the increase of PM 2.5 The concentration increased first and then tended to saturation, F = 5380.278, P < 0.01, from 400 μg / m 3 To 600 μg / m 3 PM 2.5 The concentration gradient changes at 400 μg / m 3 To 600 μg / m 3 Among the changes, the removal rate of modified Fritillaria tibetica was the highest at 32.81%.

[0127] 5) Effect of different adsorption time on PM 2.5 Effect of adsorption

[0128] When PM in the closed box 2.5 Concentration: 500±5μg / m 32 g of modified Tibetan Fritillaria thunbergii treated with cellulase with a mesh size of 40 was added, and the adsorption lasted for 30 min, 60 min, 90 min, 120 min, and 150 min. 2.5 The detector measures the PM in the closed box after adsorption. 2.5 Concentration. Record various data before and after adsorption and calculate the removal rate. The results are as follows: Fig.11 As shown. Fig.11 It can be seen that the adsorption capacity of modified Tibetan Fritillaria increases first and then tends to saturation with the increase of adsorption time, F=191.623, P<0.01. In the change from 30min to 150min, the adsorption effect increases with the increase of adsorption time. When it is 150min, the removal rate is as high as 35.85%.

[0129] 4. Characterization analysis and adsorption mechanism analysis

[0130] 1) Elemental analysis

[0131] The modified Fritillaria tibetica, the unmodified Fritillaria tibetica and the PM adsorbed 2.5 The modified Tibetan Fritillaria were subjected to elemental analysis, and the results are shown in Table 7.

[0132] Table 7 Elemental analysis of three materials

[0133]

[0134] As can be seen from Table 7, in the three materials, the C content is as high as about 40%. Comparing the other three elements, it can be found that the N and S contents in the Tibetan Fritillaria are significantly higher than those in the other two modified materials. On the contrary, the C and H contents are significantly lower than those in the other two modified materials. Therefore, the modified Tibetan Fritillaria adsorbs a large amount of PM 2.5 , can optimize the ambient air quality.

[0135] 2) Infrared spectroscopy analysis

[0136] The modified Fritillaria tibetica prepared by the above optimal method, the unmodified Fritillaria tibetica and the modified Fritillaria tibetica after adsorbing PM2.5 were analyzed by infrared spectroscopy. The results are as follows: Fig.12 As shown. Fig.12 It can be seen that: at the wave number of 3496cm -1 The stretching vibration peak of OH appeared nearby. The transmittance of the absorption peak increased significantly after modification and adsorption, indicating that the cellulase treatment affected the number and activity of OH in the Tibetan Fritillaria material, and OH had a certain influence in the adsorption process; at the wave number of 2925cm -1Nearby is the absorption peak of CH. From the changes of the three lines, it can be analyzed that the CH group also plays a certain role in this adsorption process; the wave number is 1650cm -1 The C=N group absorption peak appears at 1300 cm-1. The transmittance of this absorption peak gradually decreases after modification and absorption, proving that this group also plays a role in the adsorption process. -1 ~600cm -1 There are also changes in the absorption peaks, and there are also obvious changes in the single-bond groups in this area, indicating that such groups may also play a role in the adsorption process.

[0137] 3) Scanning electron microscopy analysis

[0138] The modified Fritillaria tibetica, the unmodified Fritillaria tibetica and the PM adsorbed 2.5 The modified Fritillaria tibetica was analyzed by scanning electron microscope. Fig.13 As shown. Fig.13 It can be seen that the original Tibetan Fritillaria is basically all cellulose. The Tibetan Fritillaria degrades and modifies the cellulose through cellulase, destroying the original cell wall structure and retaining a large number of dense fiber network structures, presenting a loose and porous form, which greatly enhances the adsorption capacity; the fiber network structure of the Tibetan Fritillaria adsorbent microscopic surface after adsorption is reduced, and the folds are filled, that is, the PM adsorption 2.5 Caused by.

[0139] 4) Specific surface area and pore size analyzer analysis

[0140] Through the BET experiment, the specific surface area and pore volume of the modified Tibetan Fritillaria prepared by the above optimal method were measured to obtain the specific surface area parameters of the material, which can intuitively illustrate that the larger pore size of the modified Tibetan Fritillaria can provide adsorption sites. The results are shown in Table 8.

[0141] Table 8 Specific surface area and pore size analysis of modified Tibetan Fritillaria

[0142] Test items Modified Fritillaria tibetica <![CDATA[Specific surface area (m 2 / g)]]> 1.614 <![CDATA[Pore volume (cm 3 / g)]]> 0.002 Pore ​​size analysis (μm) 3.298

[0143] 5) Adsorption mechanism analysis

[0144] The mathematical expression describing the relationship between the adsorption amount and the initial concentration at a constant temperature can be used to reveal the nature of the adsorption phenomenon and help study the adsorption capacity of the adsorbent for a specific substance. The model used in the present invention is the Langmuir isotherm, as shown in formula (1) and the Freundlich isotherm, as shown in formula (2).

[0145] Langmuir model: C / Qm+1 / Qmb=C / Q Formula (1);

[0146] Freundlich model: K×C 1 / n =Q formula (2);

[0147] Taking the logarithm of both sides of equation (2) can turn it into a linear form:

[0148] lgK+(1 / n)lgC=lgQ Formula (3)

[0149] Where: C is the equilibrium concentration in μg / m 3 ; q is the equilibrium adsorption capacity, the unit is μg / g; Qm is the saturated adsorption capacity, the unit is μg / g; b is the adsorption equilibrium constant, which represents the magnitude of the adsorption force on the adsorbate binding force; K is the Friedrich constant; n in 1 / n is the adsorption index.

[0150] The equilibrium adsorption amount calculation formula is shown in formula (4):

[0151] Q=(C0-C)V / m Formula (4)

[0152] Where: C0 is the initial concentration, the unit is mg / m 3 ; V is the volume of the closed box, in m 3 ; m is the mass of the adsorbent, the unit is g.

[0153] Take five transparent closed boxes of the same size, light mosquito coils in each of them, and wait for the PM in the five boxes to 2.5 The concentrations of 3 450 μg / m 3 , 500 μg / m 3 , 550μg / m 3 , 600 μg / m 3 2 g of the optimally treated modified Fritillaria tibetica was evenly spread in the culture dish, and PM in each transparent closed box was recorded in turn after 30 minutes. 2.5 The concentration of adsorption was calculated and the results were fitted with the isotherm curve, such as Fig.14 and Fig.15 As shown by Fig.14 It can be seen that as the adsorption temperature gradually rises, the adsorption amount reaches the maximum value, and then the temperature continues to rise and the change range of the adsorption amount decreases. The thermodynamic parameters are shown in Table 9.

[0154] Table 9 Thermodynamic parameters

[0155] T / K <![CDATA[ΔG0(kJ / mol)]]> <![CDATA[ΔH0(kJ / mol)]]> <![CDATA[ΔS0(J·mol -1 ·K -1 )]]> 292 -6038.8 11.09919 58.7185 294 -6148.66 11.09919 58.7185 296 -6261.85 11.09919 58.7185 298 -6491.16 11.09919 58.7185 300 -6524.31 11.09919 58.7185

[0156] Note: ΔG0 is the change in Gibbs free energy of adsorption, ΔH0 is the change in enthalpy of adsorption, and ΔS0 is the change in entropy of adsorption.

[0157] As shown in Table 9, ΔH0>0 and ΔG0<0, it means that the Tibetan Fritillaria adsorbs PM 2.5 It is an endothermic process that can proceed spontaneously. Fig.15 It can be seen that the correlation coefficient of the fitted thermodynamic curve R 2 It is close to 1, which fits well with the thermodynamic equation, indicating that the modified Fritillaria tibetica adsorbs PM 2.5 Follow the laws of thermodynamics.

[0158] Adsorption isotherm: At 25℃, PM 2.5 The initial concentration was used as a single variable for the adsorption test. The adsorption isotherm model parameters are shown in Table 10, and the adsorption amount is calculated as shown in Table 10. Fig.16 , draw the adsorption isotherm. First, use the Langmuir model to fit, and determine the horizontal and vertical coordinates according to formula (2) to draw the graph. Fig.17 As shown; the Freundlich model is used for fitting, and the horizontal and vertical coordinates are determined according to formula (4), see Fig.18 shown.

[0159] Table 10 Adsorption isotherm model parameters From Table 10, we can see that in the Freundlich model, the correlation coefficient R 2 Closer to 1, that is, more inclined to

[0160]

[0161] The Freundlich isotherm adsorption model shows that the surface of the modified Fritillaria tibetica has many active sites, mainly multi-molecular layer adsorption, and in the Freundlich model, the larger the K value, the stronger the adsorption capacity, indicating that the adsorption material has good adsorption of PM2.5. It can be judged that the number of effective functional groups on the surface of Fritillaria tibetica has increased after being modified by cellulase, which has improved the adsorption of PM 2.5 adsorption effect.

[0162] Adsorption dynamic curve: Take a transparent closed box (0.45^3=0.091m 3 ), light a mosquito coil and wait for PM 2.5 The concentration was constant at 500 μg / m 3 2 g of the optimally treated modified Fritillaria tibetica was evenly spread in a culture dish, and the corresponding PM was recorded at 30 min, 60 min, 90 min, 120 min, and 150 min. 2.5 The indicated value was obtained, and the adsorption amount after different time was calculated. The adsorption kinetic curve was drawn, and the pseudo-first-order kinetic equation and pseudo-second-order kinetic equation were fitted to explore its adsorption mechanism.

[0163] PM 2.5 The initial concentration was stabilized at 500 μg / m 3The adsorption test was carried out with the adsorption time as the single variable, and the parameters of the kinetic equation are shown in Table 11. The optimal modified Fritillaria tibetica adsorption amount changes with the adsorption time. Fig.19 According to formula (5), the horizontal and vertical coordinates are determined and the pseudo-first-order kinetic equation is fitted. Fig. 20 As shown; according to formula (6), the horizontal and vertical coordinates are determined for plotting, and the pseudo-second-order kinetic equation is fitted, see Fig.21 shown.

[0164] The pseudo-first-order kinetic equation is lgQ-lg(Q-q)=k1t / 2.303 (5);

[0165] The pseudo-second-order kinetic equation is t / q-t / Q=1 / (k2·Q 2 ) formula (6);

[0166] Where: t represents time, in min; q refers to the adsorption amount at time t, in mg / g; Q refers to the equilibrium adsorption amount, in mg / g; k1 represents the first-order adsorption kinetic constant, in min -1 ; k2 represents the secondary adsorption kinetic constant, in g·mg -1 ·min -1 .

[0167] Table 11 Kinetic equation parameters

[0168]

[0169] Depend on Fig. 20 and Fig.21 It can be seen from Table 11 that the pseudo-first-order equation phase constant is 0.0004606, and the pseudo-second-order equation constant is 0.0236. The pseudo-second-order constant is greater than the pseudo-first-order constant, indicating that the Tibetan Fritillaria residue has an effect on PM 2.5 The adsorption changes follow the pseudo-secondary adsorption kinetic model, which means that the adsorption process is also a physical and chemical mixed adsorption dominated by chemical adsorption. The initial concentration of 503μg / m 3 , PM after 16 hours 2.5 The concentration dropped to 72 μg / m 3 , in the national standard 75μg / m 3 the following.

[0170] 5. Effects of different adsorbents on PM 2.5 The adsorption effect

[0171] At room temperature of 21°C, 2g of activated carbon with a particle size of 60 mesh, diatomaceous earth with a particle size of 325 mesh, macroporous adsorption AB-8 resin, bamboo charcoal with a particle size of 18 mesh, modified Fritillaria thunbergii with a particle size of 60 mesh, and Fritillaria thunbergii with a particle size of 40 mesh were taken respectively; a cigarette was lit in a sealed box, and the air quality detector data in the sealed box showed 500μg / m3 When the above six materials are placed in a closed box for adsorption for 30min, 60min, 90min, 120min and 150min respectively, the adsorption values ​​are recorded and their removal rates are compared. The results are as follows Fig. 22 The analysis tables are shown in Tables 12 and 13. Fig. 22 It can be seen that the removal rate is in the following order from large to small: modified Tibetan Fritillary > diatomaceous earth > activated carbon > bamboo charcoal > resin > unmodified Tibetan Fritillary, and the removal rate of modified Tibetan Fritillary adsorption material is significantly better than that of the other four materials, and the characteristic biological resources have achieved high-value utilization.

[0172] Table 12PM 2.5 ANOVA table

[0173] Sources of variation SS df MS F P Material 9898.151 5 1979.63 3110.139 0.0001 time 164.9738 4 41.2434 64.7964 0.0001 Material × Time 12.7302 20 0.6365 29.4272 0.0001 error 1.2545 58 0.0216 - - Total variation 10077.16 89 - - -

[0174] Table 13 Effect of different materials on PM adsorption by Fritillaria tibetica 2.5 Comparison of the effects

[0175]

[0176]

[0177] By analyzing Table 12, we can see that different materials and different adsorption times are the main factors affecting the removal rate, and the interaction between these two factors can also affect the removal rate; from Table 13, we can see that the adsorption capacity of modified Tibetan Fritillaria is much better than that of the other four materials.

[0178] 6. Cycle adsorption times

[0179] After each adsorption, the modified Fritillaria tibetica was treated by exposure to sunlight, and then the PM 2.5 The results of the first five repeated tests showed that the modified Fritillaria tibetica had an adsorption capacity of PM 2.5 There is no obvious difference in the adsorption performance of the modified Fritillaria tibetica, and the adsorption effect is relatively stable. From the sixth to the seventh adsorption, the adsorption effect of the modified Fritillaria tibetica is greatly weakened. However, it can be seen that after seven cycles of use, the modified Fritillaria tibetica still has a certain adsorption effect. Fig.23 Therefore, the modified Fritillaria tibetica biosorbent can be recycled at least seven times.

[0180] Through the above experiments, it can be seen that by optimizing the preparation conditions of cellulase treatment, the three factors that most significantly affect the removal rate are cellulase concentration, enzymatic hydrolysis temperature, and enzyme inactivation temperature. The three-factor five-level quadratic orthogonal rotation regression combination is used for optimization. By analyzing single factors, double factors, and using DPS data processing software, the best adsorption combination of the three factors is obtained, which is a cellulase concentration of 3.8 mg / ml, an enzymatic hydrolysis temperature of 58°C, and an enzyme inactivation temperature of 78°C. At this time, the removal rate reaches the highest value of 34.04%. The modified Tibetan Fritillaria prepared according to this combination, and then the removal rate is measured. The measurement is repeated three times, and the average value is 33.64%. The measured value / software predicted value is 0.998, which is basically consistent, and the model is established.

[0181] The adsorption process of modified Fritillaria dasyphylla residue was fitted by Langmuir isotherm and Freundlich isotherm, and the obtained rule was: the correlation coefficient R between this adsorption process and the Freundlich isotherm fitting was 2 The value is close to 1, which indicates that the adsorption process of the modified Fritillaria tibetica is in accordance with the law and is a multi-molecular layer multi-site adsorption. The experimental data were fitted with the pseudo-first-order kinetic curve and the pseudo-second-order kinetic curve respectively and the results were analyzed: The chemically modified Fritillaria tibetica adsorbs PM 2.5 The correlation coefficient R 2 It reached 0.996, indicating that the adsorption process was mainly chemical adsorption.

[0182] Under the same conditions, the adsorption effects of the optimal modified Tibetan Fritillaria, original Tibetan Fritillaria residue and other four adsorbents were compared, and the results were arranged from large to small as follows: modified Tibetan Fritillaria residue > diatomaceous earth > activated carbon > bamboo charcoal > original Tibetan Fritillaria.

[0183] FTIR infrared analysis shows that the number of OH, CH, C=N, CC and other groups in the modified Tibetan Fritillaria changes and affects the adsorption process, thereby improving the adsorption effect; element analysis shows that the content of C, H, N, and S elements in the modified Tibetan Fritillaria increases, thereby improving the adsorption effect.

[0184] When recycled for the fifth time, PM 2.5 The initial concentration was 500 μg / m 3 After 4 hours of adsorption, the removal rate reached 30.23%.

[0185] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0186] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A modified Fritillaria tibetica, characterized in that: The modified Fritillaria tibetica is obtained by placing the Fritillaria tibetica in a cellulase solution, using the cellulase to destroy the cell wall structure of the Fritillaria tibetica and retaining the fiber network structure, and reacting at 50°C to 55°C for 20min to 22min. The mass volume ratio of the Tibetan Fritillaria and the cellulase solution is 10g:50mL-55mL; The concentration of the cellulase solution is 2.5 mg / mL to 3.8 mg / mL.

2. The modified Tibetan Fritillaria according to claim 1, characterized in that The particle size of the Tibetan Fritillaria is 40 meshes to 100 meshes.

3. The modified Tibetan Fritillaria according to claim 1, characterized in that The enzyme inactivation temperature is 70° C. to 75° C. and the time is 8 min to 10 min.

4. The method for preparing the modified Fritillaria tibetica according to any one of claims 1 to 3, characterized in that: The following steps are involved: Mixing the Fritillaria tibetana and the cellulase solution in a mass volume ratio of 10 g: 50 mL to 55 mL, reacting at 50° C. to 55° C. for 20 min to 22 min, and then inactivating the enzyme at 70° C. to 75° C. for 8 min to 10 min to obtain the Fritillaria tibetana after the enzyme is inactivated; The enzyme-inactivated Fritillaria tibetica is rinsed to neutrality, dried, and crushed to obtain the modified Fritillaria tibetica; The concentration of the cellulase solution is 2.5 mg / mL to 3.8 mg / mL.

5. A modified Fritillaria tibetica as claimed in any one of claims 1 to 3 for preparing PM adsorption 2.5 application in products.

6. A PM 2.5 The removal method is characterized in that The modified Fritillaria tibetica according to any one of claims 1 to 3 is placed in a medium containing PM 2.5 In the gas, the modified Fritillaria tibetica is used to treat PM 2.5 Adsorb to remove PM from the gas 2.5 .

7. The PM according to claim 6 2.5 The removal method is characterized in that The adsorption time is 30 min to 150 min.

8. The PM according to claim 6 2.5 The removal method is characterized in that The adsorption temperature is 25°C to 28°C.

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