Mixed enzyme modified millet straw adsorbent for removing TVOC (Total Volatile Organic Compounds) as well as preparation method and application of mixed enzyme modified millet straw adsorbent

Abstract

The invention discloses a mixed enzyme modified millet straw adsorbent for removing TVOC (Total Volatile Organic Compounds) as well as a preparation method and application thereof, the preparation method comprises the following steps: cooking pretreatment: cutting millet straws into small sections, cooking in boiling water, and softening a fiber structure; preparing a mixed enzyme: preparing a mixed enzyme solution of amylase, cellulase and hemicellulase for later use; enzymatic hydrolysis reaction: immersing the pretreated straws into a mixed enzyme solution, and reacting in a constant-temperature water bath at 45-55 DEG C for a period of time; carrying out enzyme deactivation treatment: transferring into a water bath at 70-80 DEG C, and carrying out enzyme deactivation treatment; rinsing: repeatedly washing with distilled water until the solution is neutral, and removing residual enzyme and degradation products; drying: placing in an air dry oven, and drying at constant temperature to constant weight; and crushing and sub-packaging: sieving after crushing, and sealing and storing for later use.

Description

Technical Field

[0001] This invention relates to the field of adsorbent technology, and more specifically to a mixed enzyme-modified millet straw adsorbent for removing TVOC, its preparation method, and its application. Background Technology

[0002] Millet is one of the important grain crops in northern regions, with a long history of cultivation. Millet grains contain protein, fat, carbohydrates, as well as various vitamins and minerals, making them highly nutritious and a traditional staple food.

[0003] Millet straw is the residue left after grain harvesting in agricultural production and belongs to agricultural and forestry waste. As a high-quality biomass resource, agricultural and forestry waste provides a feasible path for energy structure transformation and green, low-carbon development, aligning with global emission reduction targets and the national "carbon neutrality" policy. Agricultural and forestry waste is diverse, including agricultural waste (such as straw, corn cobs, and rice husks), forestry residues, animal excrement, and industrial biomass residues, and its resource utilization is receiving increasing attention. Traditional treatment methods, such as open burning or natural decomposition, are both inefficient and polluting to the environment.

[0004] In recent years, indoor air quality has received increasing attention, with pollution sources including both indoor and outdoor environments. Total volatile organic compounds (TVOCs) are a significant component of indoor air pollution, exhibiting high volatility at room temperature and encompassing aromatic compounds, aldehydes, ketones, and other organic substances. TVOCs pose potential health hazards; therefore, in-depth research into their sources, properties, and control methods is crucial for improving air quality and protecting public health, while also providing a scientific basis for the formulation of relevant policies and standards.

[0005] Foreign research focuses on the development of new adsorption materials, such as charged adsorbents, natural materials, and modified biochar, with the aim of improving the adsorption level of certain pollutants, such as carbon dioxide, heavy metals, and organic pollutants. Foreign research also values ​​the sustainability and environmental friendliness of materials, prompting continuous updates in adsorbent technology for pollution control.

[0006] In recent years, China has made significant progress in the production and performance research of adsorbents such as bamboo charcoal, straw silicon carbide, and corn stalk core biochar. A mature technical system has been established for bamboo charcoal adsorbents, from raw material selection to processing, ensuring its high efficiency and stability. Straw silicon carbide adsorbents have undergone more refined processing through pretreatment and the integration of silicon, further enhancing their adsorption performance. Corn stalk core biochar adsorbents, through a unique production path, have demonstrated their application potential in the environmental protection field.

[0007] Overall, although domestic and international research on adsorbents focuses on different aspects, they all aim to achieve high efficiency, low cost, and environmental protection, and are committed to solving environmental pollution problems. In the future, with technological development and deeper interdisciplinary cooperation, the research and application prospects of adsorbent materials will be even broader.

[0008] Millet straw is a typical agricultural waste that has long been neglected or treated inefficiently. If it is turned into an adsorbent, it can not only effectively solve the problem of waste disposal, but also create new economic value. This resource utilization method not only fits the concept of sustainable development, but also opens up a new direction for the comprehensive utilization of agricultural waste.

[0009] Therefore, how to provide a mixed enzyme-modified millet straw adsorbent for removing TVOC, its preparation method, and its application are technical problems that urgently need to be solved by those skilled in the art. Summary of the Invention

[0010] In view of this, the present invention provides a mixed enzyme modified millet straw adsorbent for removing TVOC, its preparation method and application.

[0011] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing a mixed enzyme-modified millet straw adsorbent for removing TVOCs includes the following steps: (1) Steaming pretreatment: Cut the millet stalks into small pieces and steam them in boiling water to soften the fiber structure. (2) Prepare mixed enzymes Prepare a mixed enzyme solution of amylase, cellulase and hemicellulase for later use; (3) Enzymatic hydrolysis reaction The pretreated straw is immersed in the mixed enzyme solution and reacted in a constant temperature water bath at 45-55℃ for a period of time. (4) Enzyme inactivation treatment Transfer to a 70-80℃ water bath for enzyme inactivation treatment; (5) Rinse Rinse repeatedly with distilled water until neutral to remove residual enzymes and degradation products; (6) Drying Place in a forced-air drying oven and dry at a constant temperature until constant weight; (7) Crushing and Packaging After crushing, sieve and seal for later use.

[0012] Preferably, the cutting in step (1) is to cut to 2-3cm; the steaming time is 25-35min.

[0013] Preferably, the mass ratio of amylase, cellulase and hemicellulase in step (2) is 1:2.841:1.42; and the concentration of the mixed enzyme solution is 1.5 mg / mL.

[0014] Preferably, the constant temperature water bath reaction time in step (3) is 28.2 min.

[0015] Preferably, the enzyme inactivation treatment time in step (4) is 25-35 min.

[0016] Preferably, the temperature for constant temperature drying in step (6) is 25-35 min.

[0017] Preferably, the sieving in step (7) is sieve 40 mesh.

[0018] Another object of the present invention is to provide a mixed enzyme-modified millet straw adsorbent for removing TVOC, which is prepared by the above-described preparation method.

[0019] As can be seen from the above technical solution, compared with the prior art, the present invention has the following beneficial effects: (1) This invention uses a mixed enzyme solution composed of amylase, cellulase and hemicellulase in a certain ratio (1:2.841:1.42) to treat millet straw, which increases the specific surface area of ​​millet straw and improves the adsorption of TVOC. The preparation process is simple and easy to operate.

[0020] (2) The reaction conditions in the entire preparation process are mild, and no strong acids, strong bases or other highly polluting chemical reagents are used, thus avoiding environmental pollution and conforming to green development. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0022] Figure 1 Scanning electron microscopy (SEM) images of raw millet straw and the millet straw adsorbent prepared in Example 1 before and after adsorption of TVOC.

[0023] Figure 2 Fourier transform infrared spectra of raw millet straw and millet straw adsorbent prepared in Example 1 before and after adsorption of TVOC (a:b:c) a: raw millet straw; b: optimized millet straw; c: adsorbed millet straw.

[0024] Figure 3The graph shows the effect of amylase concentration in ethyl acetate-assisted amylase on TVOC adsorption.

[0025] Figure 4 The graph shows the effect of the total concentration of lignin peroxidase and cellulase on TVOC adsorption.

[0026] Figure 5 The graph shows the effect of the total concentration of amylase, cellulase and hemicellulase on TVOC adsorption.

[0027] Figure 6 This is a diagram showing the adsorption effect of slag particle size.

[0028] Figure 7 The adsorption effect is shown in the figure.

[0029] Figure 8 This is a diagram showing the effect of temperature adsorption.

[0030] Figure 9 This is a diagram showing the effect of humidity adsorption.

[0031] Figure 10 The graph shows the effect of different adsorption times on the removal of TVOC from modified millet straw.

[0032] Figure 11 The figure shows the effect of different TVOC concentrations on the removal rate of modified straw.

[0033] Figure 12 The effects of the concentrations and ratios of amylase, cellulase, and hemicellulase on the removal rate were investigated. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1 This embodiment provides a method for preparing a mixed enzyme-modified millet straw adsorbent for removing TVOCs, comprising the following steps: (1) Steaming pretreatment: Cut the millet straw into 2-3cm sections and steam it in boiling water for 30 minutes to soften the fiber structure.

[0036] (2) Preparation of mixed enzymes: Prepare a mixed solution with a total enzyme concentration of 1.5 mg / mL (amylase: cellulase: hemicellulase = 1:2.841:1.42) in 500 mL.

[0037] (3) Enzymatic hydrolysis: The pretreated straw was immersed in the mixed enzyme solution and reacted in a constant temperature water bath at 50℃ for 28.2 min.

[0038] (4) Enzyme inactivation treatment: Transfer to a 75°C water bath and heat for 30 minutes (to ensure complete inactivation of the three enzymes).

[0039] (5) Rinse: Rinse repeatedly with distilled water until neutral to remove residual enzymes and degradation products.

[0040] (6) Drying: Place in a forced-air drying oven and dry at a constant temperature of 80℃ until constant weight.

[0041] (7) Crushing and packaging: After crushing, pass through a 40-mesh sieve and seal for storage.

[0042] Experimental Analysis: Blank group: Untreated millet straw; Experimental group: Millet straw was treated with a solution of amylase:cellulase:hemicellulase = 1:2:1 (mixed solutions with total enzyme concentrations of 2, 4, 6, 8, and 10 mg / mL were prepared, 500 mL for each group). Control group: Ethyl acetate-assisted amylase (1) Steaming pretreatment: Cut the millet straw into small sections of 2-3 cm, remove the impurities from the straw, and put the straw into boiling water to steam for 30 min.

[0043] (2) Soaking: Prepare a 0.15 mol / L ethyl acetate solution, and soak an equal amount of cooked straw in the solution, keeping it at a constant temperature of 70 ℃ in a constant temperature water bath.

[0044] (3) Enzymatic hydrolysis: Prepare amylase solutions with concentration gradients of 1 mg / mL, 2 mg / mL, 3 mg / mL, 4 mg / mL and 5 mg / mL. Transfer the soaked straw into these enzyme solutions and react in a constant temperature water bath at 55 ℃ for 60 min.

[0045] (4) Enzyme inactivation treatment: The sample was treated in an 80 ℃ water bath for 15 min.

[0046] (5) Rinsing: Rinse the straw repeatedly with distilled water until its pH value is close to neutral (pH≈7).

[0047] (6) Drying: Place the rinsed sample in a forced-air drying oven and dry it at a constant temperature of 80 ℃ to ensure that the sample is fully dehydrated.

[0048] (7) Crushing and packaging: Crush the dried straw into 40-mesh particles, seal and store for later use.

[0049] Synergistic effect of lignin peroxidase and cellulase (1) Cooking pretreatment: Cut the millet straw into uniform segments of 2-3 cm and boil it in boiling water for 15 minutes to soften the fiber structure.

[0050] (2) Mixed enzyme concentration gradient: The ratio of lignin peroxidase to cellulase is fixed at 1:1. Prepare 500 mL of mixed enzyme solutions of 1, 2, 3, 4 and 5 mg / mL. For example, the 1 mg / mL group is 0.5 mg / mL lignin peroxidase + 0.5 mg / mL cellulase.

[0051] (3) Enzymatic hydrolysis reaction: The pretreated straw was divided into 5 groups and placed in mixed enzyme solutions of different concentrations. The reaction was carried out in a constant temperature water bath at 55℃ for 60 min.

[0052] (4) Enzyme inactivation treatment: The sample was treated in a 75 ℃ water bath for 20 min.

[0053] (5) Rinse: Rinse repeatedly with distilled water until neutral to remove residual enzymes and degradation products.

[0054] (6) Drying: Place in a forced-air drying oven and dry at a constant temperature of 80 ℃ until completely dehydrated.

[0055] (7) Crushing and packaging: After crushing, the adsorbent particles are passed through a 40-mesh sieve to obtain homogeneous adsorbent particles, which are then sealed and stored away from light.

[0056] Determination method of TVOC adsorption by millet straw (1) The removal rate determination system was constructed by conducting parallel experiments using five sets of equal-volume closed experimental chambers. Millet straw samples were fixedly placed in the chambers, and solvent-based paint was used as the TVOC pollution source to construct a simulated pollution environment. During the experiment, the five chambers were kept running synchronously, and the temperature and relative humidity were strictly controlled. The parallel experimental design minimized systematic errors.

[0057] (2) Quantitative determination of leakage rate N0: Immediately after opening the experimental chamber, place a glass petri dish containing paint and a TVOC detection probe inside, seal it, and continue monitoring until the initial reading n0 stabilizes at 1.8 (unit: mg / m³). 3 The result indicates that the TVOC concentration in the chamber has reached a dynamic equilibrium. After removing the pollution source, continuous monitoring was conducted for 30 minutes. At this time, the instrument reading was n, and the concentration value N0 was recorded. The leakage rate calculation formula is: N0 = n0 - n (1) (3) Calculation method of adsorption efficiency N: A TVOC pollution source was placed in the experimental chamber. After the gas diffused evenly, the pollution source was removed. When the detector showed that the concentration n1 was stable at the target pollution level, 2g of millet straw adsorption material was quickly added. After 30 minutes, the material was removed and the concentration n2 was recorded. The formula for calculating adsorption efficiency is: N=(n1-n2) / (n1-N0)×100% (2) Comparison of modification methods like Figure 3 As shown, the yield of this treatment method is between 58% and 65%. When ethyl acetate and amylase are used in combination, the adsorption efficiency initially decreases and then increases. The highest removal rate reaches 13.07%, indicating that this method has good treatment potential. like Figure 4 As shown, the yield of this treatment method ranged from 57% to 63%. The removal rate fluctuated significantly with changes in enzyme concentration, with a maximum removal rate of 13.69%. The wide distribution of removal rate values ​​in the experimental data indicates significant differences in adsorption efficiency under different concentration conditions. like Figure 5 As shown, the yield of this treatment method is between 57% and 65%. The trend shows that the TVOC removal rate first decreases and then increases with increasing concentrations of amylase, cellulase, and hemicellulase. The removal rate reaches its highest value of 15.82% when the enzyme concentration is at a low level, representing the optimal value under the experimental conditions.

[0058] The above comparison shows that the product in the experimental group of this invention has the best adsorption effect.

[0059] Results and Analysis of Quadratic Regression Orthogonal Rotation Experiment As shown in Table 1, adsorption experiments were conducted based on this table to calculate the removal rate of TVOC by millet straw, and the results were analyzed using DPS software.

[0060] Table 1. Quadratic Regression Orthogonal Rotational Combination Design Table

[0061] Establish regression equation Statistical analysis of the experimental results (Table 1) was conducted using DPS. The regression equation is: Y = 17.99151 - 1.36947X1 - 0.71812X2 - 0.36605X3 - 2.22948X1 2 0.34 + 086 x 2 2 -0.59253X3 2 -1.56125X1X2+0.53625X1X3+0.34625X2X 3。

[0062] The analysis of variance results in Table 2 show that, at a significance level of 1%, variable X2 2 X3 2 With X1 2There are extremely significant differences between them. An orthogonalization method was used in the design to ensure that the regression coefficients do not affect each other. Insignificant variables were eliminated by setting α=0.10, thereby optimizing the model. A quadratic variance model was established, resulting in the simplified regression equation Y=17.99151 -1.36947X1-2.22948X1 2 -1.56125X1X2, detailed information is shown in Table 3.

[0063] Table 2. Analysis of first-order variance table

[0064] Investigation of Two-Factor Effects The analysis of variance results (Table 4) show that all three factors (X1, X2, and X3) have varying degrees of influence on the adsorption effect during their interactions. Particularly in the comparison of the interactions between X1X3 and X2X3, the interaction between X1X2 is highly significant (P<0.01), indicating that the concentration ratio of amylase, cellulase, and hemicellulase has a highly significant impact on the adsorption effect. The specific effects of the interaction between X1X2 are detailed in Table 4, and the three-dimensional visualization results of their interaction relationship are shown below. Figure 12 As shown.

[0065] Table 4. Effects of the concentrations and ratios of amylase, cellulase, and hemicellulase on the removal rate.

[0066] Figure 12 The results show that the removal rate initially increases and then decreases with increasing enzyme concentration. This is because enzyme molecule aggregation at high concentrations leads to reduced treatment efficiency. As the ratio of cellulase to hemicellulase among the three enzymes increases, the removal rate continues to rise and reaches its optimal level.

[0067] Optimal combination scheme and result verification Based on DPS software analysis, the optimal preparation parameters for the concentrations and ratios of amylase, cellulase, and hemicellulase were: X1 = -1, X2 = 1.682, X3 = -1.682. Under these conditions, the millet straw removal rate was 19.76%. A large-scale experiment was conducted under optimized conditions of a mixed enzyme concentration of 1.5 mg / mL, an enzyme ratio (amylase:cellulase:hemicellulase = 1:2.841:1.420), and an enzymatic hydrolysis time of 28.2 min. The results showed that the millet straw removal rate was 19.69%, and the ratio to the predicted value was 0.99, close to 1, indicating accurate prediction and a valid model.

[0068] Research on the effects of environmental factors on TVOC removal a. Particle size experiment of residue: Millet straw residue was sieved through 20, 40, 60, 80 and 100 mesh as a particle size gradient. 2g of each particle size material was taken and an adsorption experiment was carried out in a closed box with a TVOC concentration of 1.8mg / m³ for 30min. The removal rate of the five materials was measured at the same time, and the optimal particle size was selected.

[0069] Test results are shown Figure 6 ,like Figure 6 As shown, the effects of millet straw adsorbents with different particle sizes on TVOC levels up to 5% were significantly different (F=5.19, P=0.0159<0.05). The best removal effect was observed when the millet straw material was 40 mesh. As can be seen from the figure, the removal rate was highest at 40 mesh (19.69%), and then began to decline. This may be because the TVOC composition is relatively complex, and increasing the mesh size would affect adsorption.

[0070] b. Dosage Experiment: Select 40-mesh slag and weigh 1g, 2g, 3g, 4g, and 5g (a total of 5 gradients). Conduct an adsorption experiment for 30 minutes under the condition of TVOC concentration of 1.8mg / m³. Analyze the effect of different dosages on the removal rate and find the optimal dosage.

[0071] See results Figure 7 ,like Figure 7 As shown, with the increase of millet straw residue addition, the removal rate first increased and then decreased. Different amounts of millet straw adsorbent showed highly significant differences in the removal rate of TVOC at the 1% level (F=9.478, P=0.002<0.01). When the addition amount reached 3g, the removal rate reached its highest value of 20.25%, and then began to decline. This phenomenon is related to the reduction in effective adsorption area caused by material accumulation.

[0072] c. Temperature experiment: Take 2g of 40-mesh residue and conduct an adsorption experiment for 30min at 5 temperature gradients (27℃, 29℃, 31℃, 33℃, 35℃) at a TVOC concentration of 1.8mg / m³. Calculate the removal rate at different temperatures and study the effect of temperature on adsorption performance.

[0073] See results Figure 8 ,like Figure 8 As shown, the differences reached a highly significant level of 1% (F=16.996, P=0.0002<0.01). When the room temperature was 29℃, the removal rate of the millet material reached its maximum value (19.53%), and the adsorption effect was the best. When the temperature was less than or greater than 29℃, the removal rate showed a decreasing trend.

[0074] d. Humidity experiment: Take 2g of 40-mesh residue and set 5 humidity gradients (24%RH, 29%RH, 34%RH, 39%RH, 44%RH) at a TVOC concentration of 1.8mg / m³. Perform an adsorption experiment for 30min and analyze the removal rate under different humidity conditions.

[0075] See results Figure 9 ,like Figure 9 As shown, the removal rate of millet straw material in the sealed chamber showed a trend of first increasing and then decreasing with changes in humidity. Different humidity levels had significant differences in the removal rate of PM10 to the 5% level (F=4.942, P=0.0185<0.05). The removal rate was the highest at 34%RH, reaching 19.75%.

[0076] e. Two-factor experiment on adsorption time and temperature: The adsorption time of 30, 60, 90, 120 and 150 min was used as the main factor, and the temperature of 27℃, 31℃ and 35℃ was used as the secondary factor. 2g of modified millet straw was taken and adsorption experiments were carried out at different temperatures. The removal rate was measured and the synergistic effect of adsorption time and temperature was studied.

[0077] See results Figure 10 ,like Figure 10 As shown: The extremely significant differences in the 1% adsorption level achieved by millet straw adsorbent at different temperatures and adsorption times (F... 吸附时间 =286.597, P=0.0001<0.01; F 温度 =97.272, P=0.0001<0.01), the temperature-adsorption-time interaction reached a highly significant difference at the 5% level (F 吸附时间×温度 =2.893, P=0.0163<0.05). When investigating the effects of adsorption time (primary factor) and temperature (secondary factor) on the removal efficiency of TVOC from modified millet straw, it was found that the removal rate increased with prolonged adsorption time, rising from 18.6% at 30 min to 47.62% at 150 min at 27℃. However, at the same adsorption time, increasing temperature led to a decrease in the removal rate, which is related to the reduced surface activity of the adsorbent material at high temperatures.

[0078] f. Two-factor experiment on initial TVOC concentration and temperature: Initial TVOC concentration was used as the main factor (1.6, 1.7, 1.8, 1.9, 2.0 mg / m³). 3 Temperature was used as a secondary factor (3 levels). 2g of modified millet straw was used to conduct an adsorption experiment for 30min at different initial concentrations. The removal rate was measured, and the synergistic effect of initial concentration and temperature was analyzed.

[0079] See results Figure 11 ,like Figure 11 As shown, the millet straw adsorbent exhibited extremely significant differences at different temperatures and initial concentrations reaching the 1% level (F0).浓度 =36.375, P=0.0001<0.01; F 温度 =39.834, P=0.0001<0.01). When investigating the effects of initial TVOC concentration (primary factor) and temperature (secondary factor) on the removal efficiency of modified millet straw, it was found that the removal rate increased with increasing initial TVOC concentration, rising from 15.79% at 1.6 mg / m³ to 18.09% at 2 mg / m³ at 27℃. Under other temperature conditions, the removal rate also showed an increasing trend with increasing initial concentration. However, at the same initial concentration, increasing temperature led to a decrease in the removal rate.

[0080] Characterization analysis (1) Scanning Electron Microscopy (SEM) Characterization: SEM was used to compare the surface morphology and internal fiber structure of the original millet straw and the samples before and after adsorption. For example... Figure 1 As shown, untreated raw millet straw has few surface pores and significant shadows, which is not conducive to the adsorption of TVOC. After optimization treatment, the surface structure of millet straw is significantly looser, with a richer distribution of wrinkles and pores. This structure has extremely strong adsorption performance. The surface of the millet straw after the adsorption experiment is smooth and flat with few wrinkles, indicating that TVOC particles fill the pores and wrinkles on the surface of the millet straw during the adsorption process.

[0081] (2) Fourier Transform Infrared Spectroscopy (FTIR) Characterization and Adsorption Mechanism Investigation: FTIR technology was used to analyze the functional groups of raw, modified, and adsorbed millet straw residues, and the adsorption mechanism was analyzed based on spectral characteristics. For example... Figure 2 As shown, 3500cm -1 The decrease in transmittance around 100°C indicates that the optimized treatment increased the hydroxyl (-OH) content of the millet straw. The subsequent increase in transmittance after adsorption suggests that some hydroxyl groups participated in the adsorption reaction, leading to a reduction in their quantity.

[0082] (3) Elemental composition analysis: Elemental analysis was performed on the three materials to understand their compound composition. The results are shown in Table 5. Table 5

[0083] Table 5 shows that the original millet straw contained high levels of C and H elements, and the lowest level of S element. After treatment with three enzymes, the C and H elements increased slightly, while the S and N elements decreased slightly. After adsorbing TVOC, the C element decreased slightly, the H element increased slightly, and the N and S elements increased, indicating that the modified millet straw effectively adsorbed TVOC components containing N and S.

[0084] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0085] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a mixed enzyme-modified millet straw adsorbent for removing TVOC, characterized in that, Includes the following steps: (1) Steaming pretreatment: Cut the millet stalks into small pieces and steam them in boiling water to soften the fiber structure. (2) Prepare mixed enzymes Prepare a mixed enzyme solution of amylase, cellulase and hemicellulase for later use; (3) Enzymatic hydrolysis reaction The pretreated straw is immersed in the mixed enzyme solution and reacted in a constant temperature water bath at 45-55℃ for a period of time. (4) Enzyme inactivation treatment Transfer to a 70-80℃ water bath for enzyme inactivation treatment; (5) Rinse Rinse repeatedly with distilled water until neutral to remove residual enzymes and degradation products; (6) Drying Place in a forced-air drying oven and dry at a constant temperature until constant weight; (7) Crushing and Packaging After crushing, sieve and seal for later use.

2. The method for preparing a mixed enzyme-modified millet straw adsorbent for removing TVOC according to claim 1, characterized in that, The cutting in step (1) refers to cutting to 2-3cm; the steaming time is 25-35min.

3. The method for preparing a mixed enzyme-modified millet straw adsorbent for removing TVOC according to claim 1, characterized in that, The mass ratio of amylase, cellulase and hemicellulase in step (2) is 1:2.841:1.42; the concentration of the mixed enzyme solution is 1.5 mg / mL.

4. The method for preparing a mixed enzyme-modified millet straw adsorbent for removing TVOC according to claim 1, characterized in that, The reaction time in the constant temperature water bath in step (3) is 28.2 min.

5. The method for preparing a mixed enzyme-modified millet straw adsorbent for removing TVOC according to claim 1, characterized in that, The enzyme inactivation treatment time in step (4) is 25-35 min.

6. The method for preparing a mixed enzyme-modified millet straw adsorbent for removing TVOC according to claim 1, characterized in that, The constant temperature drying temperature in step (6) is 25-35 min.

7. The method for preparing a mixed enzyme-modified millet straw adsorbent for removing TVOC according to claim 1, characterized in that, The sieving mentioned in step (7) is sieving through a 40-mesh sieve.

8. A mixed enzyme-modified millet straw adsorbent for removing TVOC, characterized in that, It is prepared by the preparation method according to any one of claims 1-7.

9. The application of the mixed enzyme-modified millet straw adsorbent for removing TVOC as described in claim 8 in TVOC adsorption.

10. The application of the mixed enzyme-modified millet straw adsorbent for removing TVOC according to claim 9 in TVOC adsorption, characterized in that, The adsorption conditions were: TVOC concentration 2.0 mg / m³. 3 Temperature 29℃, humidity 34%RH, addition amount 3g, adsorption time 150min.

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