Sugarcane peel adsorbent as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of adsorbents, and particularly relates to a sugarcane peel adsorbent and a preparation method and application thereof. The preparation method comprises the following steps: performing cooking treatment on the sugarcane peel, softening and expanding cellulose and hemicellulose in the sugarcane peel, and exposing hydroxyl groups on the cellulose and hemicellulose to obtain cooked sugarcane peel; immersing the cooked sugarcane peel in an ester compound aqueous solution, and drying to obtain a sugarcane peel adsorbent; wherein the concentration of the ester compound aqueous solution is 0.059 mol / L to 0.5 mol / L. The preparation method provided by the invention overcomes the problems of high cost and difficulty in large-scale industrial production when the biomass adsorbent is prepared by using mixed enzyme in the prior art; and the sugarcane peel adsorbent obtained by the preparation method can effectively improve the defect of PM10 adsorption capacity of the existing adsorbent, realizes resource utilization of the waste sugarcane peel, and reduces resource waste and environmental pollution.

Description

Technical Field

[0001] The invention belongs to the technical field of adsorbents, and in particular relates to a sugarcane peel adsorbent and a preparation method and application thereof. Background Art

[0002] With the acceleration of urbanization and the continuous expansion of industrial production, air pollution is becoming increasingly serious, especially PM10 fine particles, which pose a serious threat to the environment and human health. Therefore, the development of efficient, economical and environmentally friendly air purification materials has become a hot topic in current research. Sugarcane peel, as a rich agricultural waste, contains rich natural cellulose, lignin and polysaccharide components, has potential adsorption capacity, and is a high-quality raw material for the preparation of biosorbents.

[0003] At present, there has been a study on "a preparation method and application of a lavender residue adsorbent" that uses an enzyme-alkali method to treat lavender residues to prepare a biosorbent, and has achieved corresponding results. The method mainly includes pretreatment of lavender residues, preparation and soaking of a mixed enzyme solution, alkaline treatment of a potassium hydroxide solution, and drying steps. These steps act together on the lavender residues, causing changes in its fiber structure, thereby improving its adsorption performance. However, there are significant problems with this preparation method. On the one hand, the enzymes used in the mixed enzyme solution, such as hemicellulase, laccase, and trypsin, are expensive and not conducive to large-scale industrial production. On the other hand, although the enzyme-alkali treatment enhances the adsorption effect of lavender residue adsorbent on PM10, its adsorption rate is only 15.52%, which is difficult to meet the needs of practical applications. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a sugarcane peel adsorbent and a preparation method and application thereof, wherein the sugarcane peel is used as a raw material, the sugarcane peel after steaming is immersed in an ester compound aqueous solution, and the sugarcane peel adsorbent is obtained through an esterification reaction. The preparation method of the present invention overcomes the problems of high cost and difficulty in large-scale industrial production when using mixed enzymes to prepare biomass adsorbents in the prior art; and the sugarcane peel adsorbent obtained by the preparation method of the present invention can also effectively improve the deficiencies of the existing adsorbents in PM10 adsorption capacity, realize the resource utilization of the waste of sugarcane peel, and reduce resource waste and environmental pollution.

[0005] In order to achieve the above purpose, the technical solution adopted in this application is:

[0006] The first object of the present invention is to provide a method for preparing a sugarcane peel adsorbent, comprising the following steps:

[0007] S1. Cleaning samples: Take sugarcane peel and rinse it under running water to remove dust and impurities on the surface of the sugarcane peel.

[0008] S2. Steaming and crushing treatment: The washed sugarcane peel is placed in boiling water for steaming. During the steaming process, the cellulose and hemicellulose inside the sugarcane peel are softened and expanded, and the hydroxyl groups on the cellulose and hemicellulose are exposed. At the same time, the soluble sugar, pigment and ash in the sugarcane peel are effectively dissolved and partially removed, and then dried and crushed to obtain the steamed sugarcane peel.

[0009] S3. Esterification reaction: preparing an aqueous solution of an ester compound, immersing the boiled sugarcane peel in the aqueous solution of the ester compound, and causing the ester group of the ester compound to react with the hydroxyl groups on the cellulose and hemicellulose in the boiled sugarcane peel to form more microporous and mesoporous structures, and then drying to obtain a sugarcane peel adsorbent; wherein the concentration of the aqueous solution of the ester compound is 0.059 mol / L to 0.5 mol / L.

[0010] S4. Adjusting pH: Rinse the sugarcane peel adsorbent with deionized water several times until it is neutral to remove residual ester compounds.

[0011] S5. Drying the sample: placing the rinsed sugarcane peel adsorbent in a blast drying oven for drying.

[0012] Preferably, in the aqueous solution of ester compounds, the ester compound is selected from ethyl acetate, butyl acetate, amyl acetate, hexyl acetate, heptyl acetate, octyl acetate, isoamyl acetate or isooctyl acetate.

[0013] More preferably, the ester compound is selected from ethyl acetate. The reaction conditions of ethyl acetate are mild and it is not easy to destroy the basic structure of sugarcane peel. Its good volatility facilitates subsequent removal and reduces the pollution to the sugarcane peel adsorbent. In addition, its toxicity is low and the impact on the environment and human health is small.

[0014] Preferably, the conditions for the esterification reaction are: immersing in the aqueous solution of the ester compound for 20 h to 28 h.

[0015] Preferably, the conditions for the esterification reaction are: immersion at room temperature for 24 hours.

[0016] Preferably, the cooking conditions are: cooking at 80°C to 100°C for 20min to 60min.

[0017] Preferably, in step S2, the powder is crushed to 8-80 mesh.

[0018] Preferably, in step S5, the sugarcane peel adsorbent is rinsed to neutrality and then dried at 150°C.

[0019] The second object of the present invention is to provide a sugarcane peel adsorbent prepared by the above preparation method.

[0020] The third object of the present invention is to provide the use of the above-mentioned sugarcane peel adsorbent in the preparation of PM10 adsorbent.

[0021] Preferably, the application method is: placing the sugarcane peel adsorbent in a closed air atmosphere containing PM10 for adsorption treatment.

[0022] Preferably, the mass ratio of the sugarcane peel adsorbent to the amount of PM10 is 1g to 3g: 550μg / m 3 ~950 μg / m 3 .

[0023] Preferably, the adsorption temperature of the sugarcane peel adsorbent is room temperature, and the adsorption time is 20 min to 290 min.

[0024] Preferably, the adsorption temperature of the sugarcane peel adsorbent is 19°C to 27°C.

[0025] Preferably, the particle size of the sugarcane peel adsorbent is 18 meshes and the adsorption temperature is 25°C.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The present invention provides a method for preparing a sugarcane peel adsorbent, wherein the sugarcane peel is subjected to a cooking process, during which the cellulose and hemicellulose inside the sugarcane peel are softened and expanded, and the hydroxyl groups on the cellulose and hemicellulose are exposed, thereby obtaining the cooked sugarcane peel; the cooked sugarcane peel is immersed in an aqueous solution of an ester compound, and the ester group of the ester compound reacts with the hydroxyl groups on the cellulose and hemicellulose in the cooked sugarcane peel to form more micropores and mesoporous structures, and the sugarcane peel adsorbent is obtained after drying; wherein the concentration of the aqueous solution of the ester compound is 0.059 mol / L to 0.5 mol / L. Compared with the traditional enzyme-alkali method, the preparation method of the present invention is simpler, more environmentally friendly, and has lower cost. More importantly, the preparation method of the present invention overcomes the problem of high cost and difficulty in large-scale industrial production when using mixed enzymes to prepare biomass adsorbents in the prior art; and the sugarcane peel adsorbent obtained by the preparation method of the present invention can also effectively improve the shortcomings of the existing adsorbent in PM10 adsorption capacity, realize the resource utilization of the waste of sugarcane peel, and reduce resource waste and environmental pollution.

[0028] Among them, during the cooking process, the cellulose and hemicellulose components inside the sugarcane peel soften and expand significantly due to heat. At the same time, the soluble sugars, pigments and ash in the sugarcane peel are effectively dissolved and partially removed; the cooking process also significantly improves the porosity and surface area of ​​the sugarcane peel by destroying its original cell structure; during the esterification reaction, the ester compounds penetrate into the pores and cell walls of the sugarcane peel and react with the hydroxyl groups on the cellulose and hemicellulose in the cooked sugarcane peel to esterify, which not only changes the charge properties and hydrophilicity of the surface of the cooked sugarcane peel, but also enhances the structural stability of the sugarcane peel adsorbent, thereby improving its adsorption performance. Through the esterification reaction, the hydrophilicity and hydrophobicity of the surface of the sugarcane peel adsorbent are balanced, enabling it to more effectively capture and fix PM10 particles in the air. In addition, the esterification reaction also promotes the formation of micropores and mesopores inside the cooked sugarcane peel, further increasing the specific surface area and pore volume, and providing more adsorption sites for PM10 particles.

[0029] 2. The sugarcane peel adsorbent obtained by the present invention has better adsorption performance and good environmental protection characteristics than diatomaceous earth, activated carbon and macroporous adsorption resin AB-8 in the prior art. It can not only solve the problems of resource waste and environmental pollution caused by insufficient utilization of sugarcane peel, but also significantly enhance its adsorption capacity for PM10 in the air, thereby achieving the dual goals of resource utilization and environmental protection.

[0030] 3. The present invention also uses sugarcane peel adsorbent to remove PM10 in the air. When the particle size of the sugarcane peel adsorbent is 18 mesh, the added amount is 2g, and the adsorption temperature is 21°C, the sugarcane peel adsorbent has the best adsorption effect on PM10, and the highest adsorption rate is 33.16%.

[0031] 4. The ester compounds used in the esterification process are relatively cheap and easy to obtain. At the same time, the processing conditions are mild and easy to control, which is conducive to industrial production. In addition, the sugarcane peel adsorbent after esterification reaction also has good stability and regeneration, and can maintain good adsorption performance after multiple uses, further reducing the cost of use. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a single factor effect analysis diagram of the sugarcane peel adsorbent of Examples 1 to 19.

[0033] Figure 2 The figures are the adsorption effect diagrams of the sugarcane peel adsorbent prepared in Example 10 on PM10, wherein (a) is the adsorption effect diagram of the sugarcane peel adsorbent prepared in Example 10 on PM10 at different adsorption time and temperature, (b) is the adsorption effect diagram of the sugarcane peel adsorbent prepared in Example 10 on PM10 at different particle sizes, and (c) is the adsorption effect diagram of the sugarcane peel adsorbent prepared in Example 10 on PM10 at different addition amounts.

[0034] Figure 3 The figures are scanning electron microscope images of the original sugarcane peel and the sugarcane peel adsorbent prepared in Example 10, wherein (a) is a scanning electron microscope image of the original sugarcane peel, and (b) is a scanning electron microscope image of the sugarcane peel adsorbent prepared in Example 10.

[0035] Figure 4 ] are infrared curves of the original sugarcane peel and the sugarcane peel adsorbent prepared in Example 10 before and after adsorption, wherein a is the original sugarcane peel, b is the sugarcane peel adsorbent prepared in Example 10 before adsorption, and c is the sugarcane peel adsorbent prepared in Example 10 after adsorption.

[0036] Figure 5 This is a fitting diagram of the thermodynamic equation for PM10 adsorption by the sugarcane peel adsorbent prepared in Example 10.

[0037] Figure 6 This is a diagram showing the adsorption effect of the sugarcane peel adsorbent prepared in Example 10 at different initial mass concentrations of PM10.

[0038] Figure 7 These are isotherms of PM10 adsorbed by the sugarcane peel adsorbent prepared in Example 10, wherein (a) is the Langmuir isotherm of PM10 adsorbed by the sugarcane peel adsorbent prepared in Example 10, and (b) is the Freundlich isotherm of PM10 adsorbed by the sugarcane peel adsorbent prepared in Example 10.

[0039] Figure 8 This is a diagram showing the adsorption effect of the sugarcane peel adsorbent prepared in Example 10 on PM10 at different adsorption times.

[0040] Fig. 9 The graphs are rate equations for PM10 adsorption by the sugarcane peel adsorbent prepared in Example 10, wherein (a) is a pseudo-first-order rate equation graph, and (b) is a pseudo-second-order rate equation graph.

[0041] Fig.10 This is a diagram showing the adsorption effect of the sugarcane peel adsorbent prepared in Example 10 on PM10 at different adsorption temperatures.

[0042] Fig.11 This is a diagram showing the adsorption effect of different adsorption materials on PM10.

[0043] Fig.12 This is a diagram showing the desorption and regeneration adsorption effect of the sugarcane peel adsorbent prepared in Example 10.

[0044] Fig.13The figures are the adsorption effects of the sugarcane peel adsorbents prepared in Examples 16 to 20 and the sugarcane peel adsorbents prepared in Comparative Examples 1 to 3 on PM10, wherein (a) is the sugarcane peel adsorbent prepared in Comparative Example 1, (b) is the sugarcane peel adsorbent prepared in Comparative Example 2, (c) is the sugarcane peel adsorbent prepared in Examples 16 to 20, and (d) is the sugarcane peel adsorbent prepared in Comparative Example 3. DETAILED DESCRIPTION

[0045] The technical solution of the present invention will be clearly and completely described below in combination with the data in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. 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.

[0046] It should be noted that the professional terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. Unless otherwise specifically stated, the various raw materials, reagents, instruments and equipment used in the following embodiments of the present invention can be purchased from the market or prepared by existing methods.

[0047] At present, some results have been achieved in the preparation of lavender residue adsorbent by treating lavender residue with an enzyme-alkali method, but this method has obvious limitations and shortcomings. First, the mixed enzyme solution used in the enzyme-alkali method, including hemicellulase, laccase and trypsin, is expensive, and requires high economic investment for acquisition and application, which limits the popularization and application of this method in large-scale industrial production. Secondly, although the enzyme-alkali treatment can enhance the adsorption performance of lavender residue adsorbent, its adsorption effect on PM10 is not outstanding, and the adsorption rate is only 15.52%, which is far lower than the demand for high-efficiency adsorption materials in the field of air purification.

[0048] In view of the defects of the prior art, the present invention proposes a method for preparing a sugarcane peel adsorbent, comprising the following steps: steaming the sugarcane peel, during which the cellulose and hemicellulose in the sugarcane peel are softened and expanded, and the hydroxyl groups on the cellulose and hemicellulose are exposed to obtain the steamed sugarcane peel; immersing the steamed sugarcane peel in an ester compound aqueous solution, wherein the ester group of the ester compound reacts with the hydroxyl groups on the cellulose and hemicellulose in the steamed sugarcane peel to form more microporous and mesoporous structures, and drying to obtain the sugarcane peel adsorbent; wherein the concentration of the ester compound aqueous solution is 0.059 mol / L to 0.5 mol / L.

[0049] The present invention overcomes the problems of high cost and difficulty in large-scale industrial production when using mixed enzymes to prepare biomass adsorbents in the prior art by adopting a method combining cooking treatment and esterification reaction. Among them, the cooking treatment not only effectively removes impurities in sugarcane peel, but also significantly improves its porosity and surface area, providing favorable conditions for subsequent modification. The esterification reaction changes the charge properties and hydrophilicity of the surface of the cooked sugarcane peel through the esterification reaction, while also enhancing the structural stability of the sugarcane peel adsorbent, thereby improving its adsorption performance. The esterification reaction also promotes the formation of micropores and mesopores inside the cooked sugarcane peel, further increases the specific surface area and pore volume, and provides more adsorption sites for PM10 particles. In addition, the sugarcane peel adsorbent obtained by the preparation method of the present invention effectively improves the shortcomings of the existing adsorbents in PM10 adsorption capacity, and realizes the resource utilization of the waste sugarcane peel.

[0050] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with specific embodiments.

[0051] Example 1

[0052] A method for preparing a sugarcane peel adsorbent comprises the following steps:

[0053] S1. Cleaning samples: Weigh the sugarcane peel and rinse it under running water to remove dust and impurities on the surface of the sugarcane peel.

[0054] S2. Steaming and crushing: the washed sugarcane peel is steamed in boiling water for 50 minutes, and then placed in an electric constant temperature blast drying oven for drying and crushing to obtain the steamed sugarcane peel.

[0055] S3, ethyl acetate modification: the boiled sugarcane peel is placed in a 0.09 mol / L ethyl acetate solution and soaked for 26 hours for ethyl acetate modification.

[0056] S4. Adjusting pH: Rinse the sugarcane peel modified with ethyl acetate with deionized water for several times until it becomes neutral.

[0057] S5. Drying the sample: placing the rinsed sugarcane peel in a blast drying oven at 150° C. and drying for 3 h to constant weight to obtain a sugarcane peel adsorbent.

[0058] Example 2

[0059] A method for preparing a sugarcane peel adsorbent has the same preparation steps as those in Example 1, except that the cooking time is replaced from 50 min to 30 min.

[0060] Example 3

[0061] A method for preparing a sugarcane peel adsorbent has the same preparation steps as those in Example 1, except that the immersion time is replaced from 26 h to 22 h.

[0062] Example 4

[0063] A method for preparing a sugarcane peel adsorbent has the same preparation steps as those in Example 3, except that the cooking time is replaced from 50 min to 30 min.

[0064] Example 5

[0065] A method for preparing a sugarcane peel adsorbent has the same preparation steps as those in Example 1, except that the concentration of the ethyl acetate solution is replaced from 0.09 mol / L to 0.07 mol / L.

[0066] Example 6

[0067] A method for preparing a sugarcane peel adsorbent has the same preparation steps as those of Example 5, except that the cooking time is replaced from 50 min to 30 min.

[0068] Example 7

[0069] A method for preparing a sugarcane peel adsorbent has the same preparation steps as those of Example 5, except that the immersion time is replaced from 26 h to 22 h.

[0070] Example 8

[0071] A method for preparing a sugarcane peel adsorbent has the same preparation steps as those of Example 7, except that the cooking time is replaced from 50 min to 30 min.

[0072] Example 9

[0073] A method for preparing a sugarcane peel adsorbent has the same preparation steps as those in Example 1, except that the cooking time is replaced from 50 min to 40 min, the concentration of the ethyl acetate solution is replaced from 0.09 mol / L to 0.063 mol / L, and the immersion time is replaced from 26 h to 24 h.

[0074] Example 10

[0075] A method for preparing a sugarcane peel adsorbent is the same as the preparation steps of Example 9, except that the concentration of the ethyl acetate solution is replaced from 0.063 mol / L to 0.097 mol / L.

[0076] Embodiment 11

[0077] A method for preparing a sugarcane peel adsorbent has the same preparation steps as Example 10, except that the concentration of the ethyl acetate solution is replaced from 0.097 mol / L to 0.08 mol / L, and the immersion time is replaced from 26 h to 20.6 h.

[0078] Example 12

[0079] A method for preparing a sugarcane peel adsorbent has the same preparation steps as those in Example 1, except that the immersion time is replaced from 20.6 h to 27.4 h.

[0080] Example 13

[0081] A method for preparing a sugarcane peel adsorbent has the same preparation steps as Example 12, except that the cooking time is replaced from 40 min to 23.2 min, and the immersion time is replaced from 27.4 h to 24 h.

[0082] Embodiment 14

[0083] A method for preparing a sugarcane peel adsorbent has the same preparation steps as Example 13, except that the cooking time is replaced from 23.2 min to 56.8 min.

[0084] Embodiment 15

[0085] A method for preparing a sugarcane peel adsorbent has the same preparation steps as Example 13, except that the cooking time is replaced from 23.2 min to 40 min.

[0086] Based on Example 15, 9 groups of parallel tests were conducted, and the average removal rate was 19.75%.

[0087] Example 16

[0088] A method for preparing a sugarcane peel adsorbent has the same preparation steps as those in Example 1, except that the concentration of the ethyl acetate solution is replaced from 0.09 mol / L to 0.1 mol / L.

[0089] Embodiment 17

[0090] A method for preparing a sugarcane peel adsorbent is the same as the preparation steps of Example 16, except that the concentration of the ethyl acetate solution is replaced from 0.1 mol / L to 0.2 mol / L.

[0091] Embodiment 18

[0092] A method for preparing a sugarcane peel adsorbent is the same as the preparation steps of Example 16, except that the concentration of the ethyl acetate solution is replaced from 0.1 mol / L to 0.3 mol / L.

[0093] Embodiment 19

[0094] A method for preparing a sugarcane peel adsorbent is the same as the preparation steps of Example 16, except that the concentration of the ethyl acetate solution is replaced from 0.1 mol / L to 0.4 mol / L.

[0095] Embodiment 20

[0096] A method for preparing a sugarcane peel adsorbent is the same as the preparation steps of Example 16, except that the concentration of the ethyl acetate solution is replaced from 0.1 mol / L to 0.5 mol / L.

[0097] Embodiment 21

[0098] A method for preparing a sugarcane peel adsorbent has the same preparation steps as Example 13, except that the cooking time is replaced from 23.2 min to 20 min.

[0099] Embodiment 22

[0100] A method for preparing a sugarcane peel adsorbent has the same preparation steps as Example 13, except that the cooking time is replaced from 23.2 min to 60 min.

[0101] On the basis of the single factor experiment, ethyl acetate concentration (X1), immersion time (X2) and cooking time (X3) were selected as optimization factors, as shown in Table 1, and 23 different optimization conditions of sugarcane peel adsorbent were obtained, as shown in Table 2. A variance analysis was performed on the DPS treatment system, and the results are shown in Table 3.

[0102] Table 1 Coding table of three factors and five levels

[0103]

[0104]

[0105] Table 2 Three-factor quadratic regression orthogonal rotation combination test design and result test table

[0106]

[0107] Table 3 ANOVA table

[0108]

[0109]

[0110] In order to optimize the best process conditions for extracting sugarcane peel adsorbent, a quadratic regression orthogonal rotation analysis experiment was carried out with ethyl acetate concentration (X1), immersion time (X2) and cooking time (X3) as independent variables and adsorption rate (Y) as response value. The experimental results were analyzed using the DPS system, and the mathematical model regression equation of ethyl acetate concentration (X1), immersion time (X2), cooking time (X3) and adsorption rate (Y) was obtained as follows:

[0111] Y=19.69744+1.28693X1+0.03262X2-1.40216X3+4.35557X1 2 +0.67861X2 2 +0.307

[0112] 38X3 2 +1.57000X1X2-0.27000X1X3+1.06000X2X3

[0113] When the significance level is 0.05, the F 失拟 =2.709 <F 0.05(5，8) =3.69, F 回归 =5.233>F 0.01(9，13) =4.19, indicating that unknown factors can be ignored and the regression equation is accurate in prediction.

[0114] In order to further evaluate the effect of the interaction between X1, X2, and X3 on the comprehensive score of adsorption rate Y and determine the optimal level range of each factor, a corresponding response surface diagram was drawn according to the analysis results, as shown in Figure 1 shown.

[0115] observe Figure 1 , combined with the data in Table 3, it can be concluded that in the three groups of two-factor interactions of X1X2, X1X3, and X2X3, the influence of X1X2 is more significant. Therefore, the effects of ethyl acetate concentration (X1) and immersion time (X2) on adsorption rate were further explored, and the remaining factors were set to 0 level, as shown in Table 4:

[0116] Table 4 Effect of ethyl acetate concentration and immersion time on adsorption rate

[0117]

[0118]

[0119] The experimental data were analyzed using DPS software. From the results in Table 4, it can be concluded that the levels of the three factors when the Y value is the largest are (-1.682, -1.682, 1.682). It is predicted that the adsorption rate of the sugarcane peel adsorbent can reach the highest 34.37%. When the experimental reduction is equal to the same level, that is, the ethyl acetate concentration is 0.063 mol / L, the immersion time is 23.2 h, and the cooking time is 56.8 min, the average value of the three experiments of the sugarcane peel adsorbent is 32.86%, and the ratio of the two reaches 0.96, which is close to 1, indicating that the model prediction is accurate.

[0120] Comparative Example 1

[0121] A method for preparing a sugarcane peel adsorbent, which adopts an alkali-heat method to prepare the sugarcane peel adsorbent, comprises the following steps:

[0122] S1. Cleaning samples: Weigh the sugarcane peel and soak it in clean water to remove dust and impurities on the surface of the sugarcane peel.

[0123] S2. Steaming and crushing: the washed sugarcane peel is steamed in boiling water for 40 minutes, and then placed in an electric constant temperature blast drying oven for drying and crushing to obtain the steamed sugarcane peel.

[0124] S3. Alkali heat treatment: the boiled sugarcane peel is placed in a 0.1 mol / L sodium hydroxide solution at 100° C. for 1 hour for alkaline heat treatment.

[0125] S4. Adjusting pH: Rinse the sugarcane peel after alkali heat treatment with deionized water several times until it becomes neutral.

[0126] S5. Drying the sample: placing the rinsed sugarcane peel in a blast drying oven at 150° C. and drying for 3 h to constant weight to obtain a sugarcane peel adsorbent.

[0127] On the basis of Comparative Example 1, the concentrations of sodium hydroxide solution were screened, and the concentrations were 0.2 mol / L, 0.3 mol / L, 0.4 mol / L and 0.5 mol / L respectively.

[0128] Comparative Example 2

[0129] A method for preparing a sugarcane peel adsorbent, which adopts a chemical pectin crushing method to prepare the sugarcane peel adsorbent, comprises the following steps:

[0130] S1. Cleaning samples: Weigh the sugarcane peel and soak it in clean water to remove dust and impurities on the surface of the sugarcane peel.

[0131] S2. Steaming and crushing: the washed sugarcane peel is steamed in boiling water for 40 minutes, and then placed in an electric constant temperature blast drying oven for drying and crushing to obtain the steamed sugarcane peel.

[0132] S3. Acidification treatment: The boiled sugarcane peel is placed in a 1% ammonium oxalate solution at 100° C. for 1 hour for acidification treatment.

[0133] S4. Adjusting pH: Rinse the enzyme-inactivated sugarcane peel with deionized water several times until it becomes neutral.

[0134] S5. Drying the sample: placing the rinsed sugarcane peel in a blast drying oven at 150° C. and drying for 3 h to constant weight to obtain a sugarcane peel adsorbent.

[0135] On the basis of Comparative Example 2, the mass fractions of the ammonium oxalate solutions were screened, and the mass fractions of the ammonium oxalate solutions were 1%, 2%, 3%, 4% and 5%, respectively.

[0136] Comparative Example 3

[0137] A method for preparing a sugarcane peel adsorbent, which adopts a cellulose extraction method to prepare the sugarcane peel adsorbent, comprising the following steps:

[0138] S1. Cleaning samples: Weigh the sugarcane peel and soak it in clean water to remove dust and impurities on the surface of the sugarcane peel.

[0139] S2. Steaming and crushing: the washed sugarcane peel is steamed in boiling water for 40 minutes, and then placed in an electric constant temperature blast drying oven for drying and crushing to obtain the steamed sugarcane peel.

[0140] S3. Alkali heat treatment: the boiled sugarcane peel is placed in a 0.1 mol / L sodium hydroxide solution at 100° C. for 1 hour for alkaline heat treatment.

[0141] S4. Adjusting pH: Rinse the sugarcane peel after alkali heat treatment with deionized water several times until it becomes neutral.

[0142] S5. Hydrogen peroxide modification: the rinsed sugarcane peel is placed in a 5% by mass hydrogen peroxide solution at 100° C. and soaked for 1 hour.

[0143] S6. Adjust pH: Rinse the sugarcane peel modified with hydrogen peroxide with deionized water several times until it becomes neutral.

[0144] S7. Drying the sample: placing the rinsed sugarcane peel in a forced air drying oven at 150° C. and drying for 3 h to constant weight to obtain a sugarcane peel adsorbent.

[0145] On the basis of Comparative Example 3, the mass fractions of the hydrogen peroxide solutions were screened, and the mass fractions of the hydrogen peroxide solutions were 5%, 10%, 15%, 20% and 25%, respectively.

[0146] Taking the sugarcane peel adsorbent prepared in Example 10 of the present invention as an example, it is applied to the adsorption of PM10 in the air atmosphere. The specific application method and results are as follows:

[0147] (1) Single factor test:

[0148] a. Effect of temperature on adsorption of PM10

[0149] Weigh five portions of 2g sugarcane peel adsorbent and use cigarettes to release PM10 in a closed box until the mass concentration reaches 950μg / m 3 , set the temperatures to 19℃, 21℃, 23℃, 25℃, and 27℃ respectively, adsorb for 0.5h, and calculate the adsorption rate.

[0150] b. Effect of particle size on PM10 adsorption

[0151] The crushed sugarcane peel adsorbent was passed through 8-mesh, 18-mesh, 40-mesh, 60-mesh, and 80-mesh sieves, and 2 g of sugarcane peel adsorbent with different particle sizes was weighed and placed in a culture dish. A cigarette was used to release PM10 in a closed box. When the initial mass concentration of PM10 was 950 μg / m 3 When the sugarcane peel adsorbent was placed in a closed box for adsorption for 0.5 h, the adsorption rate was calculated.

[0152] c. Effect of addition amount on adsorption of PM10

[0153] 1.0g, 1.5g, 2.0g, 2.5g, and 3.0g of sugarcane peel adsorbent were weighed and placed in culture dishes respectively. A cigarette was used to release PM10 in a closed box until the mass concentration reached 950μg / m 3 , place the sugarcane peel adsorbent in a closed box for 0.5h, and calculate the adsorption rate.

[0154] d. Effect of adsorption time on adsorption of PM10

[0155] Six portions of 2g sugarcane peel adsorbent were weighed and released PM10 in a closed box using cigarettes at room temperature until the mass concentration reached 950μg / m 3 , adsorbed for 20min, 60min, 120min210min, 270min, and 290min respectively, and the adsorption rate was calculated.

[0156] e. Effect of initial mass concentration of PM10 on adsorption of PM10

[0157] Weigh five portions of 2g sugarcane peel adsorbent and release PM10 in a closed box using cigarettes at room temperature. Set the mass concentration of PM10 to 550μg / m 3 , 650μg / m 3 , 75 μg / m3 , 850μg / m 3 , 950μg / m 3 When the specified initial mass concentration of PM10 is reached, the sugarcane peel adsorbent is placed in a closed box for adsorption for 0.5h, and the adsorption rate is calculated.

[0158] Depend on Figure 2 (a) It was found that the adsorption rate of sugarcane peel adsorbent increased first and then decreased with the increase of temperature, and the adsorption rate reached the highest 32.61% at 25℃.

[0159] Depend on Figure 2 (b) It was found that the adsorption rate of sugarcane peel adsorbent increased first and then decreased with the increase of particle size. The adsorption rate reached the highest 33.16% when the residue particle size was 18 mesh.

[0160] Depend on Figure 2 (c) It was found that the adsorption rate of sugarcane peel adsorbent first increased and then decreased with the increase of the added amount. When the added amount was 2g, the adsorption rate reached the highest 31.16%.

[0161] Table 5 Elemental analysis of the original sugarcane peel and the sugarcane peel adsorbent prepared in Example 10 before and after adsorption

[0162] Materials / Elements N％ C％ H％ S％ Raw sugar cane husk 2.136 42.88 6.524 1.0336 Sugarcane peel adsorbent before adsorption 1.716 42.54 6.602 1.0357 After adsorption by sugarcane peel adsorbent 1.904 45.73 6.509 0.9722

[0163] It can be seen from Table 5 that compared with the original sugarcane peel, the nitrogen and carbon contents of the sugarcane peel adsorbent prepared in Example 10 before adsorption slightly decreased, the hydrogen content slightly increased, and the sulfur content remained basically unchanged; while the sugarcane peel adsorbent showed a significant increase in carbon content, a slight change in nitrogen and sulfur content, and a basically unchanged hydrogen content after adsorption. This shows that the sugarcane peel adsorbent can effectively adsorb PM10 in the air.

[0164] observe Figure 3 (a) The surface of the original sugarcane peel showed a white fibrous structure, which was relatively complete and had no obvious cracks or damage. Figure 3 (b) It was concluded that the surface of the sugarcane peel adsorbent had cracks and depressions, and the structure was loose. This is because the cell structure of the sugarcane peel was destroyed during cooking, forming a loose structure, which increased the surface area and porosity of the sugarcane peel adsorbent; the esterification reaction formed more micropores and mesoporous structures, increasing the adsorption sites of the sugarcane peel adsorbent, so that the sugarcane peel adsorbent can capture and fix PM10 more effectively.

[0165] The changes of the original sugarcane peel and the sugarcane peel adsorbent before and after PM10 adsorption were further analyzed by FTIR infrared spectroscopy. Figure 4 It was found that the -OH stretching vibration peak of the original sugarcane peel first appeared at 3431 cm -1Before adsorption of sugarcane peel adsorbent, the absorption peak formed by -OH stretching vibration is at 3428cm -1 Compared with the original sugarcane peel infrared curve image, the hydroxyl group has changed. After the sugarcane peel adsorbent is adsorbed, the -OH stretching vibration peak is at 3412cm -1 It is shown that in the process of PM10 adsorption, the hydroxyl functional groups in the sugarcane peel adsorbent interacted with PM10, causing the stretching vibration peak of the hydroxyl group to shift, further proving that the sugarcane peel adsorbent has good adsorption performance for PM10.

[0166] (2) Adsorption thermodynamics

[0167] △G=-R×T×lnK...................(1)

[0168] lnK=△S / R-△H / RT............(2)

[0169] Wherein, △G is the standard Gibbs free energy (KJ / mol); R is the thermodynamic gas constant, whose value is J / (mol·K); T is the thermodynamic temperature (K); △H is the enthalpy variable of the reaction (KJ / mol); △S is the entropy variable [J / (mol·K)]; and K is the thermodynamic equilibrium constant.

[0170] Table 6 PM10 adsorption thermodynamic parameters

[0171] Temperature(℃) 19 21 23 25 27 △G -11670.7951 -11723.7837 -11806.7723 -11889.7609 -11972.7495 △H 473.5405 473.5405 473.5405 473.5405 473.5405 △S 41.4943 41.4943 41.4943 41.4943 41.4943 R 0.8314 0.8314 0.8314 0.8314 0.8314

[0172] According to formula (1) and formula (2), combined Figure 5 From the data in Table 6, it can be seen that △G is less than 0, indicating that the adsorption process is spontaneous; according to the formula lnK=△S / R-△H / RT, it can be seen that △H>0, indicating that the adsorption process is an endothermic process. Therefore, the process of sugarcane peel adsorbent PM10 is a spontaneous endothermic process.

[0173] Depend on Figure 6 It was found that the equation for the relationship between the initial concentration of PM10 and the adsorption rate is: Y=0.0044X+5.0944.

[0174] Table 7 Isotherm parameters

[0175]

[0176] Note: m is the saturated adsorption capacity (μg / g); b is the adsorption equilibrium constant; k is the Freundhch constant; n is the adsorption index (n is always greater than 1); R is the thermodynamic gas constant, and its value is J / (mol·K).

[0177] Depend on Figure 7 Figure (a) and Table 7 show that the Langmuir adsorption isotherm equation is: Y = 0.0852X + 16.062, R 2 =0.9877; Figure 7 Figure (b) and Table 7 show that the Freundlich adsorption isotherm equation is: Y = 0.2764X + 0.1817, R 2 =0.9569. Comparing the fitting results of the two equations, it is found that the fitting line of the Langmuir equation almost coincides with the data points, showing a high degree of fit. The data points of the fitting line of the Freundlich equation show a nearly linear combination trend. This result shows that the adsorption process of PM10 by sugarcane peel adsorbent is more in line with the characteristics of the Freundlich equation model, that is, the adsorption process is multi-layer adsorption, and there are a large number of active sites on the surface of the sugarcane peel adsorbent.

[0178] Depend on Figure 8 It was found that the adsorption amount of PM10 by sugarcane peel adsorbent increased with time, indicating that sugarcane peel adsorbent can be used to adsorb PM10 in the air.

[0179] Table 8 Kinetic parameters

[0180]

[0181] Note: k1 is the pseudo-first-order adsorption rate constant (min -1 ); k2 is the pseudo-secondary adsorption rate constant (μg·g -1 ·min -1 ), Q is the saturated adsorption capacity.

[0182] Depend on Fig. 9 Figure (a) and Table 8 show that the pseudo-first-order curve equation is: Y = -0.0014X + 1.2808, R 2 =0.9233, then we can infer that the k1 value of lg(Qq)=lgQ-k1t / 2.303 is 0.0032; Fig. 9 Figure (a) and Table 8 show that the equation of the quasi-secondary curve is: Y = 0.066X + 1.7946, R 2 =0.9990. It can be concluded that the adsorption of PM10 by sugarcane peel adsorbent follows the quasi-two adsorption kinetic model, that is, the adsorption of sugarcane peel adsorbent is a physical and chemical mixed adsorption dominated by chemical adsorption.

[0183] Depend on Fig.10 The results showed that the adsorption of PM10 by sugarcane peel adsorbent increased first and then decreased with the increase of temperature. The adsorption effect was best at room temperature of 25°C, with an adsorption rate of 11.47%.

[0184] (3) Horizontal comparative analysis

[0185] Test group: 2 g of the sugarcane peel adsorbent prepared in Example 10, original sugarcane peel, diatomaceous earth, activated carbon, bamboo charcoal, and macroporous resin were weighed respectively to an initial mass concentration of 950 μg / m 3 The PM10 was adsorbed and the adsorption effect was measured. The results are as follows Fig.11 shown.

[0186] observe Fig.11 It was found that the PM10 adsorption effect of the sugarcane peel adsorbent prepared in Example 10 was far superior to that of the other four materials. The five materials were compared in order of comprehensive adsorption effect: sugarcane peel adsorbent prepared in Example 10 > diatomaceous earth > activated carbon > bamboo charcoal > resin > original sugarcane peel.

[0187] (4) Desorption experimental test

[0188] The sugarcane peel adsorbent after PM10 adsorption was spread out in the sun to dry. After high temperature treatment for 2 hours, the PM10 adsorption experiment was repeated. The above steps were repeated for 6 consecutive experiments, and the adsorption rate was measured each time to further explore its adsorption performance.

[0189] observe Fig.12 It was found that the adsorption rate of the sugarcane peel adsorbent decreased significantly with the increase of the number of desorption times. It was obviously seen that after three desorptions, the rate of decrease of the adsorption rate of the sugarcane peel adsorbent increased, indicating that the sugarcane peel adsorbent can be reused many times.

[0190] Test groups: The sugarcane peel adsorbents prepared in Examples 16 to 20 and the sugarcane peel adsorbents prepared in Comparative Examples 1 to 3 were subjected to adsorption and the adsorption effects were measured.

[0191] observe Fig.13 (a) It was found that the adsorption rate of sugarcane peel adsorbent increased first and then decreased with the increase of concentration. When the sodium hydroxide concentration was 0.4 mol / L, the adsorption rate of PM10 by sugarcane peel adsorbent reached the highest 23.67%. When the sodium hydroxide concentration was 0.1 mol / L, the yield of sugarcane peel adsorbent reached the highest 72.14%. Fig.13 (b) It was found that the adsorption rate of sugarcane peel adsorbent increased first and then decreased with the increase of ammonium oxalate concentration. When the ammonium oxalate concentration was 4%, the PM10 adsorption rate of sugarcane peel adsorbent reached a maximum of 33.62%. When the ammonium oxalate concentration was 4%, the yield of sugarcane peel adsorbent reached a maximum of 72.36%. Fig.13(c) It was found that the adsorption effect of sugarcane peel adsorbent increased first and then decreased with the concentration of ethyl acetate. When the concentration of ethyl acetate was 0.08 mol / L, the adsorption rate reached a maximum of 13.85%. When the concentration of ethyl acetate was 0.06 mol / L, the yield of sugarcane peel adsorbent reached a maximum of 71.71%. Fig.13 (d) It was found that the adsorption rate of sugarcane peel adsorbent increased first and then decreased with the increase of hydrogen peroxide concentration. When the hydrogen peroxide concentration was 15%, the PM10 adsorption rate of sugarcane peel adsorbent reached a maximum of 31.15%. When the hydrogen peroxide concentration was 15%, the yield of sugarcane peel adsorbent reached a maximum of 35.31%.

[0192] 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 method for preparing a sugarcane peel adsorbent, characterized in that: The following steps are involved: The sugarcane husk is subjected to a cooking process. During the cooking process, the cellulose and hemicellulose in the sugarcane husk are softened and expanded, and the hydroxyl groups on the cellulose and hemicellulose are exposed, thereby obtaining the cooked sugarcane husk; The boiled sugarcane peel is immersed in an ester compound aqueous solution, and the ester group of the ester compound undergoes an esterification reaction with the hydroxyl groups on the cellulose and hemicellulose in the boiled sugarcane peel to form more microporous and mesoporous structures. After drying, a sugarcane peel adsorbent is obtained; wherein the concentration of the ester compound aqueous solution is 0.059 mol / L to 0.5 mol / L.

2. The method for preparing the sugarcane peel adsorbent according to claim 1, characterized in that: In the aqueous solution of the ester compound, the ester compound is selected from ethyl acetate, butyl acetate, amyl acetate, hexyl acetate, heptyl acetate, octyl acetate, isoamyl acetate or isooctyl acetate.

3. The method for preparing the sugarcane peel adsorbent according to claim 1, characterized in that: The conditions for the esterification reaction are: immersion at room temperature for 20h to 28h.

4. The method for preparing the sugarcane peel adsorbent according to claim 3, characterized in that: The conditions for the esterification reaction are: immersion at room temperature for 24 hours.

5. The method for preparing the sugarcane peel adsorbent according to claim 1, characterized in that: The conditions for the steaming treatment are: steaming at 80°C to 100°C for 20min to 60min.

6. The method for preparing the sugarcane peel adsorbent according to claim 1, characterized in that: After the cooking process, the cooked sugarcane husk is crushed to 8-80 meshes.

7. A sugarcane peel adsorbent prepared by the preparation method according to any one of claims 1 to 6.

8. Use of the sugarcane peel adsorbent according to claim 7 in preparing a PM10 adsorbent.

9. The use of the sugarcane peel adsorbent in the preparation of PM10 adsorbent according to claim 8, characterized in that: The application method is: place the sugarcane peel adsorbent in an air atmosphere containing PM10 for adsorption treatment.

10. The use of the sugarcane peel adsorbent in the preparation of PM10 adsorbent according to claim 8, characterized in that: The ratio of the mass of sugarcane peel adsorbent to the amount of PM10 is 1g~3g: 550μg / m 3 ~950 μg / m 3 .

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