A forsythia PM 10 Adsorbents and uses thereof

Abstract

This invention relates to the field of air pollution control technology, and in particular to a Forsythia suspensa PM2.5 solution. 10 Adsorbents and their applications. This invention uses Forsythia waste (such as Forsythia suspensa dead branches) as raw material, and modifies it using a citric acid-assisted ethyl acetate method, combined with specific preparation conditions, to prepare Forsythia PM. 10 Adsorbents can effectively adsorb PM in the air. 10 The Forsythia PM prepared by this invention 10 Adsorbent for PM 10 At the 1% level, its adsorption effect is significantly superior to activated carbon (granules), bamboo charcoal, diatomaceous earth, and AB-8 macroporous resin. Even after 8 desorption cycles, it still effectively adsorbs PM2.5. 10 It achieves a certain removal effect. The Forsythia PM prepared by this invention... 10 Adsorbents can not only alleviate pollution problems caused by burning and incineration, but also combine efficient utilization of waste with environmental purification, turning waste into treasure. It is a low-cost, green, environmentally friendly and renewable method.

Description

Technical Field

[0001] This invention relates to the field of air pollution control technology, and in particular to a Forsythia suspensa PM2.5 solution. 10 Adsorbents and their applications. Background Technology

[0002] PM 10 PM2.5 is a type of fine particulate matter with a diameter ≤10 μm, which is easily inhaled by the human body. It is characterized by its tiny particle size, large specific surface area, and strong adsorption capacity, making it easy to adhere to various substances. Indoor PM2.5 10 It mainly originates from paint, coatings, burning mosquito coils, moxa sticks, and smoking. It can persist in the ambient air for a long time. After being inhaled, most of it settles in the upper respiratory tract and can be cleared by the cilia mucosa, but it can still cause asthma, respiratory infections, pneumonia, and other diseases, and its impact on the body should not be underestimated.

[0003] Currently removing PM 10 The current methods still employ adsorption techniques such as activated carbon, diatomaceous earth, and electrostatic adsorption. However, the preparation of activated carbon requires carbonization at temperatures ranging from 300℃ to 600℃, and the materials are mostly non-renewable resources such as coal and petroleum coke. Furthermore, it suffers from drawbacks such as long activation times and low adsorption capacity. Diatomaceous earth is expensive, and its production is limited, with irreversible environmental impacts during extraction. Electrostatic adsorption currently has a small market, stringent requirements, and is difficult to operate.

[0004] Forsythia has extremely high medicinal value and is one of the most important and widely used medicinal plants in my country. It has abundant wild resources; however, farmers often indiscriminately harvest forsythia fruits during the normal harvest season, a practice known as "rushing to harvest the green." These forsythia plants often grow in environments overgrown with weeds and thorns, making harvesting difficult. Many farmers frequently use destructive methods such as breaking branches and forking to obtain the fruit. This practice not only wastes forsythia resources and disrupts the ecological balance but also hinders the sustainable development of forsythia. The remaining withered forsythia branches are then cut down and burned, causing irreversible damage to the environment. Summary of the Invention

[0005] To address the above problems, this invention provides a Forsythia PM... 10 Adsorbents and their applications. The Forsythia PM2.5 provided by this invention... 10 The adsorbent is prepared from the dead branches of Forsythia suspensa. It can not only alleviate the pollution problems caused by the burning of green leaves, but also combine the efficient use of waste with environmental purification, turning waste into treasure. It is a low-cost, green, environmentally friendly and renewable method.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a Forsythia PM10 Adsorbent, for preparing the Forsythia PM 10 The method for using adsorbents includes the following steps: The waste forsythia was boiled and then soaked in a citric acid solution with a concentration of 0.07 mol / L. The soaked forsythia waste was soaked in ethyl acetate solution for 29.1 h to obtain modified forsythia waste; the concentration of the ethyl acetate solution was 0.17 mol / L. The modified Forsythia waste was dried and then pulverized to obtain Forsythia PM. 10 Adsorbent.

[0007] Preferably, the material passed through a 40-mesh sieve and the material passing through the sieve is the Forsythia PM. 10 Adsorbent.

[0008] Preferably, the time for soaking the decocted forsythia waste in citric acid solution is 30 minutes.

[0009] Preferably, the forsythia waste includes dead forsythia branches.

[0010] Preferably, the drying temperature is 80°C.

[0011] This invention provides the Forsythia PM described in the above technical solution. 10 Adsorbents adsorb PM 10 Applications in [the context of the text].

[0012] Preferably, the Forsythia PM 10 Adsorbents adsorb PM 10 The ambient temperature was 24℃ and the humidity was 55%RH.

[0013] Preferably, the Forsythia PM 10 Adsorbents adsorb PM 10 The adsorption time was 40 min.

[0014] Preferably, the Forsythia PM 10 Adsorbents adsorb PM 10 PM 10 Concentration ≤400 μg / m 3 .

[0015] Preferred, Forsythia PM 10 The ratio of adsorbent to adsorption space is 2 g: 1 m 3 .

[0016] Beneficial effects: This invention uses Forsythia waste (such as Forsythia suspensa dead branches) as raw material, and modifies it using a citric acid-assisted ethyl acetate method, combined with specific preparation conditions, to prepare Forsythia PM. 10 Adsorbents can effectively adsorb PM in the air. 10 500 μg / m 3 PM 10 After 24 hours of adsorption, the concentration decreased to 106 μg / m³. 3 It meets the national secondary standard of 150 μg / m 3 The Forsythia PM prepared by this invention 10 Adsorbent for PM 10 At the 1% level, its adsorption effect is significantly superior to activated carbon (granules), bamboo charcoal, diatomaceous earth, and AB-8 macroporous resin. Even after 8 desorption cycles, it still effectively adsorbs PM2.5. 10 It achieves a certain removal effect. The Forsythia PM prepared by this invention... 10 Adsorbents can not only alleviate pollution problems caused by burning and incineration, but also combine efficient utilization of waste with environmental purification, turning waste into treasure. It is a low-cost, green, environmentally friendly and renewable method. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly described below.

[0018] Figure 1 The effect of ethyl acetate concentration on PM removal by modified Forsythia suspensa 10 The impact results; Figure 2 The effect of slag particle size on the adsorption of PM by Forsythia suspensa 10 The impact results; Figure 3 The amount added affects the adsorption of PM by Forsythia suspensa. 10 The impact results; Figure 4 To study the effects of different temperatures on the adsorption of PM by Forsythia suspensa residue 10 The impact results; Figure 5 To study the effect of different humidity levels on the adsorption of PM by Forsythia suspensa residue 10 The impact results; Figure 6 To measure the adsorption time of PM2.5 by Forsythia at different temperatures 10 The impact results; Figure 7 For different PM 10 The effect of initial concentration on the adsorption effect of Forsythia suspensa at different temperatures; in the figure, 300, 400, 500, 600 and 700 represent different PM2.5 concentrations. 10 Initial concentration, all in μg / m³3 ; Figure 8 The results of scanning electron microscopy analysis of different Forsythia species are shown; from left to right, they are the original Forsythia, the optimized Forsythia, and the Forsythia after adsorption. Figure 9 The results are infrared spectra of different morphologies of Forsythia suspensa; among them, the pink line (a) is the untreated original Forsythia suspensa, the green line (b) is the optimized Forsythia suspensa, and the light blue line (c) is the Forsythia suspensa after adsorption. Figure 10 The effect of adsorption temperature on PM 10 The effect of adsorption effect; Figure 11 Forsythia absorbs PM 10 Thermodynamic curves; Figure 12 Forsythia absorbs PM 10 Adsorption kinetics curves; Figure 13 The curve is a quasi-first-order rate equation. Figure 14 The curve is a quasi-second-order rate equation. Figure 15 Optimizing the effect of Forsythia on PM2.5 at different concentrations 10 The adsorption effect on the results; Figure 16 To optimize the effect of Forsythia on PM 10 Adsorption Langmuir isotherm results; Figure 17 To optimize the effect of Forsythia on PM 10 Adsorption Freundlich isotherm results; Figure 18 To different adsorption materials for PM 10 The results of the adsorption effect comparison; Figure 19 The results of desorption and regeneration of modified Forsythia suspensa; In the figure, different letters represent significant differences between different groups. Detailed Implementation

[0019] This invention provides a Forsythia PM 10 Adsorbent, for preparing the Forsythia PM 10 The method for using adsorbents includes the following steps: The waste forsythia was boiled and then soaked in a citric acid solution with a concentration of 0.07 mol / L. The soaked forsythia waste was soaked in ethyl acetate solution for 29.1 h to obtain modified forsythia waste; the concentration of the ethyl acetate solution was 0.17 mol / L. The modified Forsythia waste was dried and then pulverized to obtain Forsythia PM. 10 Adsorbent.

[0020] In one embodiment, the material is pulverized through a 40-mesh sieve, and the material passing through the sieve is the Forsythia PM. 10 Adsorbent. In one embodiment, the decocted Forsythia waste is soaked in citric acid solution for 30 minutes. In one embodiment, the Forsythia waste includes withered Forsythia branches. In one embodiment, the drying temperature is 80°C.

[0021] In the early stages of this invention, four methods were used to pretreat forsythia stalks: alkaline heat treatment, calcium chloride-assisted lignin peroxidase, citric acid-assisted ethyl acetate, and ethyl acetate-assisted dual enzyme treatment. These methods were used to adsorb PM2.5 under the same environmental conditions. 10 Considering cost, a suitable method was selected: citric acid-assisted ethyl acetate. Further optimization was performed using a quadratic regression orthogonal rotational combination. With an ethyl acetate concentration of 0.17 mol / L and a citric acid concentration of 0.07 mol / L, and a soaking time of 29.1 h, the predicted Ymax was 15.67%, and the measured Y was 15.58%. The actual value / model optimum value was 0.994, which is basically consistent with the results. Forsythia adsorbent was added at a particle size of 40 mesh, with an addition amount of 2 g, and PM... 10 Initial concentration 400 μg / m 3 At an adsorption time of 40 min, a temperature of 24 ℃, and a humidity of 55%RH, the modified Forsythia suspensa showed good adsorption performance against PM2.5. 10 The removal rate was the highest. Structural characterization showed that the treated Forsythia had a large specific surface area and a loose and porous surface, providing good adsorption conditions. During the adsorption process, groups such as -OH played a role; the adsorption process was more in line with pseudo-second-order kinetics and the Freundlich isotherm.

[0022] Forsythia PM prepared by this invention 10 Adsorbents can not only alleviate pollution problems caused by burning and incineration, but also combine efficient utilization of waste with environmental purification, turning waste into treasure. It is a low-cost, green, environmentally friendly and renewable method.

[0023] Based on the above advantages, the present invention provides the Forsythia PM described in the above technical solution. 10 Adsorbents adsorb PM 10 Applications in [the context of the text].

[0024] As one implementation method, the Forsythia PM 10 Adsorbents adsorb PM 10 The ambient temperature was 24℃ and the humidity was 55%RH.

[0025] As one implementation method, the Forsythia PM10 Adsorbents adsorb PM 10 The adsorption time was 40 min.

[0026] As one implementation method, the Forsythia PM 10 Adsorbents adsorb PM 10 PM 10 Concentration ≤400 μg / m 3 .

[0027] As one implementation method, Forsythia PM 10 The ratio of adsorbent to adsorption space is 2 g: 1 m 3 .

[0028] To further illustrate the present invention, the following description, in conjunction with embodiments and accompanying drawings, describes a Forsythia suspensa PM (PM) product provided by the present invention. 10 The adsorbents and their applications are described in detail, but they should not be construed as limiting the scope of protection of this invention.

[0029] Preparation Example The reagents used in the following examples were obtained from the following sources: Forsythia suspensa twigs were obtained from Shanxi Huatuo Agricultural Technology Co., Ltd.; activated carbon, diatomaceous earth and bamboo charcoal were purchased from Tianjin Ruijinte Chemical Co., Ltd.; and macroporous adsorption resin AB-8 was purchased from Tianjin Jinda Resin Factory.

[0030] Leakage rate determination of sealed chamber: ; Modified Forsythia suspensa for PM 10 Removal rate calculation formula: Removal rate = ; Modified Forsythia suspensa for PM 10 Formula for calculating adsorption capacity: ; Where: P is the empty box leakage rate; C0 is the PM in the sealed box. 10 initial concentration (μg / m 3 C represents the equilibrium concentration (μg / m³) of the Forsythia suspensa residue after adsorption in the sealed chamber. 3 V is the volume of the sealed box (m³). 3 ); q is the adsorption amount (μg / g); M is the amount of Forsythia suspensa residue added (g).

[0031] Example 1 In order to explore PM 10 Adsorption performance was assessed by treating forsythia stalks with citric acid-assisted ethyl acetate and measuring the PM2.5 removal capacity of the treated forsythia. 10 The specific capabilities are as follows: Cleaning: Rinse 30 g of dried forsythia branches under running water; Boiling: Boil the dried forsythia branches in a pot for 30 minutes; Prepare 500 mL of 0.15 mol / L citric acid solution. Soak the boiled forsythia stalks in the citric acid solution for 30 min and then remove them. Prepare 0.2 mol / L, 0.25 mol / L, 0.3 mol / L, 0.35 mol / L, and 0.4 mol / L ethyl acetate solutions. Soak equal portions of forsythia stalks in ethyl acetate solutions of different concentrations for 24 h. Rinse the forsythia stalks with water until neutral and dry them in a dryer at 80℃. Pass the crushed residue through a 40-mesh sieve and collect the sieve-passing material, then pack it into resealable bags.

[0032] The effect of ethyl acetate concentration in citric acid-assisted ethyl acetate on PM adsorption 10 The results of the impact are shown in Figure 1 The results showed that Forsythia suspensa adsorbent had an effect on PM2.5. 10 The removal rate of PM2.5 first increased and then decreased with increasing ethyl acetate concentration. When the ethyl acetate concentration was 0.25 mol / L, the modified Forsythia suspensa showed a significant effect on PM2.5 removal. 10 The removal rate was the highest at 12.97%, while the removal effect was the worst at a concentration of 0.4 mol / L ethyl acetate, with a removal rate of only 10.09%. The yield of this method was 75%.

[0033] Example 2 I. Experimental Procedure 1. Based on Example 1, the optimal modification method for Forsythia suspensa twigs was determined to be citric acid-assisted ethyl acetate modification. Three key factors were selected: ethyl acetate concentration, citric acid concentration, and soaking time. The optimal adsorption conditions for each factor were calculated, and these three factors were set to a 0 level. A three-factor, five-level coding table was created, as shown in Table 1.

[0034] Table 1. Three-Factor Five-Level Coding Table

[0035] A three-factor, five-level quadratic regression orthogonal rotational combination design table was drawn using DPS software. Based on this table, 23 different combinations of modified Forsythia suspensa residue were prepared to ensure that the modified residue was simultaneously adsorbed under the same environmental and temperature conditions, and the removal rate was obtained.

[0036] 2. Experiment on the influence of environmental factors The optimal preparation method was determined through the above experiments, and large-scale preparation of Forsythia suspensa adsorbent was carried out. Further experiments were conducted to investigate the effects of environmental factors, including residue particle size, dosage, temperature, humidity, and PM2.5. 10 The study investigated the effect of different initial concentrations and different adsorption times on the adsorption of PM2.5 by Forsythia suspensa adsorbent. 10 The adsorption effect is affected.

[0037] 3. Adsorption mechanism study a. Characterization analysis (1) Scanning electron microscopy: The surface and morphological characteristics of the original Forsythia suspensa residue, the optimized Forsythia suspensa residue, and the Forsythia suspensa residue after adsorption were observed. The changes of the material before and after modification and adsorption were observed intuitively through images.

[0038] (2) FTIR analysis: The instrument produces infrared spectra of the original Forsythia suspensa residue, the optimized Forsythia suspensa residue, and the Forsythia suspensa residue after adsorption. Specific functional groups (such as hydroxyl groups) in the molecules are identified, and the adsorption mechanism is determined based on the changes in functional groups.

[0039] (3) BET analysis: It can not only measure the specific surface area, but also analyze the porosity of the material, including pore size, pore volume and pore type, and analyze the data of the original Forsythia slag and the optimized Forsythia slag respectively.

[0040] (4) Elemental analyzer: capable of accurately determining the content of specific elements in a sample, such as C, H, S, N, etc. By analyzing the elements of three samples—original Forsythia suspensa residue, optimized Forsythia suspensa residue, and Forsythia suspensa residue after adsorption—the changes in the material before and after modification and adsorption were investigated.

[0041] b. Adsorption thermodynamics Adsorption thermodynamics is the study of energy changes and equilibrium relationships during adsorption. It analyzes the spontaneity, thermal effects, and direction of adsorption behavior through thermodynamic parameters.

[0042] The formula for calculating the heat of adsorption (ΔH) is: ; ; Where: ΔG0 is the standard Gibbs free energy, in kJ / mol; R is the thermodynamic gas constant, with a value of 8.314 J / (mol·K); T is the thermodynamic temperature, and its unit is K. ΔH0 is the enthalpy change of the reaction, with units of kJ / mol; ΔS0 is the entropy variable, with units of J / (mol·K); Kc is the thermodynamic equilibrium constant.

[0043] c. Adsorption kinetics Adsorption kinetic models are used to describe the relationship between adsorption rate and time. By using kinetic models to fit experimental data, we can further understand the adsorption mechanism more accurately and provide theoretical support for optimizing the adsorption effect.

[0044] The pseudo-first-order dynamic equation of Lagergren is: ; The pseudo-second-order dynamic equation for H0 is: ; Where: Q is the equilibrium adsorption amount (μg·g) -1 ); q is the amount of adsorption at time t (μg·g) -1 ); k1 is the first-order adsorption rate constant (min) -1 ); k2 is the second-order adsorption rate constant (g·μg). -1 ·min -1 ).

[0045] d. Adsorption isotherm Adsorption isotherms are used to describe the relationship between the amount of adsorption and the concentration of the solution at a given temperature. In this experiment, the Langmuir and Freundlich isotherms were used to fit the data to more accurately describe and analyze the adsorption process.

[0046] The expression for Langmuir is: ; The expression for Freundlich is: ; Taking the logarithm of both sides of the above equation transforms it into a linear form: ; Where: C is the equilibrium concentration (μg / m³) 3 ); q is the equilibrium adsorption capacity (μg / g); q m It is the saturated adsorption capacity (μg / g); b is the adsorption equilibrium constant; K and n represent constants at a given temperature.

[0047] 4. Different materials affect PM 10 Adsorption performance comparison Under the same level of environmental factors, 2 g of adsorbent was weighed and placed in petri dishes. Mosquito coils were lit in five sealed boxes, and the PM levels in the sealed boxes were monitored. 10 The concentrations were all 500 μg / m³ 3 At approximately 30 minutes, place the petri dish in a sealed box and observe for 30 to 150 minutes, recording the removal rate. See Table 2 for specific specifications of the adsorbent.

[0048] Table 2 Adsorbent Specifications

[0049] 5. Desorption and regeneration The optimal forsythia residue after adsorption was spread out in the sun and exposed to the sun for 2 h, and its adsorption capacity was tested. The experiment was repeated six times, and the removal rate was measured each time to further explore its adsorption performance.

[0050] II. Results and analysis 1. Influence of PM in citric acid-assisted ethyl acetate 10 There are mainly three factors affecting the removal rate: ethyl acetate concentration, citric acid concentration, and soaking time. By changing these three factors, a quadratic regression orthogonal rotation combination design table was drawn, and the adsorption of PM was carried out for 23 experiments to obtain the removal rate, as shown in Table 3. One-way analysis of variance was carried out on the DPS data processing system, and the results are shown in Table 4. 10 Table 3 Quadratic regression orthogonal rotation combination design of three factors

[0051] Table 4 One-way analysis of variance table

[0052] Table 5 Simplified regression equation analysis of variance table

[0053] 2. Using the data processing system of DPS software to analyze the experimental results, the mathematical model regression equation of ethyl acetate concentration (X1), citric acid concentration (X2), soaking time (X3), and removal rate (Y) was obtained: Y = 10.27856 + 0.24180X1 - 0.26633X2 + 0.29273X3 + 0.79547X1 2 - 0.04776X2 2 + 0.44899X3 2 - 0.41000X1X2 - 0.66250X1X3 - 0.14250X2X3; At the level of α = 0.01, F in the model 失拟 = 4.344 < 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; F 回归 = 5.629 > F0.01(9,13) = 4.19, indicating that the regression equation is extremely significant, the reliability of the experimental speculation is extremely high, the prediction is accurate, and the model is established.

[0054] 3. Conduct a significance test on the regression coefficients,剔除 the insignificant terms at the level of α = 0.10, and conduct a one-way analysis of variance on the remaining terms again, as shown in Table 5. The simplified regression equation (α = 0.10) was constructed: Y = 10.27856 + 0.79547X1 2 + 0.44899X3 2 - 0.66250X1X3.

[0055] Table 5. Analysis of Quadratic Variance

[0056] 4. The results of the two-factor effect analysis are shown in Table 6.

[0057] Table 6. Effects of ethyl acetate concentration (X1) and soaking time (X3) on removal rate

[0058] The results showed that when the citric acid concentration was constant, the removal rate of modified Forsythia decreased with increasing water bath time as the ethyl acetate concentration gradually increased at the zero level; conversely, the removal rate of modified Forsythia increased with increasing water bath time as the ethyl acetate concentration gradually decreased at the zero level. At the highest level (-1.682, 1.682), the ethyl acetate concentration was 0.17 mol / L, and the soaking time was 29.1 h, at which point the removal rate was the highest, reaching 15.67%.

[0059] 5. Using the DPS data processing system, the optimal adsorption combination for achieving the highest removal rate was determined to be (-1.682, -1.682, 1.682). Under this combination, the ethyl acetate concentration was 0.17 mol / L, the citric acid concentration was 0.07 mol / L, and the soaking time was 29.1 h. The predicted removal rate Y under these conditions was... max =15.67%, and after verification, Y=15.58%. The ratio of actual measured value to software predicted value is 0.994, which is close to 1, indicating that the model is reliable.

[0060] 6. Results and Analysis of the Experiment on the Influence of Environmental Factors Depend on Figure 2 It can be seen that Forsythia suspensa adsorbent has an effect on PM2.5. 10 The removal rate of PM2.5 first increases and then decreases with increasing slag particle size. The removal rates of Forsythia suspensa adsorbents with different slag particle sizes for PM2.5 removal are different. 10 The difference was highly significant at the 1% level (F=124.234, P=0.0001<0.01). This phenomenon is due to PM. 10 The pollutants themselves have a diameter of 10 μm. As the particle size of the slag increases, it becomes less conducive to PM2.5 concentration. 10 The adsorption of Forsythia suspensa was observed. The highest removal rate (18.30%) was achieved at a mesh size of 40, while the lowest removal rate (15.11%) was achieved at a mesh size of 100. Therefore, subsequent experiments used Forsythia suspensa adsorbent with a mesh size of 40.

[0061] Depend on Figure 3 It can be seen that Forsythia suspensa adsorbent has an effect on PM2.5. 10 The removal rate of Forsythia suspensa adsorbent first increased and then decreased with increasing dosage. Different dosages of Forsythia suspensa adsorbent showed varying effects on PM2.5 removal efficiency. 10The difference was highly significant at the 1% level (F=103.457, P=0.0001<0.01). At a dosage of 2 g, the adsorbent could cover the entire surface of the petri dish; however, with increasing dosage, the adsorbent accumulated, negatively impacting the adsorption effect. At a dosage of 2 g, the adsorbent was effective against PM2.5. 10 The highest removal rate was 17.24%. The worst rate was achieved at 5 g, at only 13.16%. Therefore, subsequent experiments used 2 g of Forsythia suspensa adsorbent.

[0062] Depend on Figure 4 It can be seen that Forsythia suspensa adsorbent has an effect on PM2.5. 10 The removal rate of PM2.5 first increased and then decreased with increasing temperature, reaching a highly significant difference at the 1% level (F=117.461, P=0.0001<0.01). Under indoor temperature of 24℃, the removal rate of Forsythia suspensa adsorbent for PM2.5 was [not specified]. 10 The highest removal rate was achieved at 15.56% for PM2.56 at 18°C. 10 The removal rate was the worst. Considering the difficulty in controlling the temperature, subsequent experiments were conducted at randomized room temperature.

[0063] Depend on Figure 5 It can be seen that Forsythia suspensa adsorbent has an effect on PM2.5. 10 The removal rate first increased and then decreased with increasing humidity. Different amounts of Forsythia suspensa adsorbent showed varying effects on PM2.5 removal. 10 The difference was highly significant at the 1% level (F=112.096, P=0.0001<0.01). The adsorption effect was best when the indoor humidity reached 55%RH, with a removal rate of 15.73%. The adsorption effect was worst when the humidity was 40%RH, with a removal rate of only 12.8%.

[0064] Depend on Figure 6 It can be seen that the Forsythia suspensa adsorbent exhibits highly significant differences (F) at different temperatures, different adsorption times, and the temperature-adsorption time interaction at the 1% level. 吸附时间 =30.061, P=0.0001<0.01; F 温度 =60.207, P=0.0001<0.01; F 吸附时间×温度 =5.507, P=0.0003<0.01). At an adsorption time of 40 min, PM2.5 was... 10 The removal rate was highest at 22℃, 24℃ and 26℃, reaching 15.33%, 15.88% and 16.75% respectively, while it was worst at 60 min, with only 12.44%, 13.79% and 14.87%.

[0065] Depend on Figure 7 It can be seen that the Forsythia suspensa adsorbent exhibits highly significant differences (F) at different temperatures, different initial concentrations, and the interaction between temperature and initial concentration. 浓度=78.951, P=0.0001<0.01; F 温度 =49.275, P=0.0001<0.01; F 浓度×温度 =6.035, P=0.0001<0.01). At an initial concentration of 400 μg / m 3 PM 10 The removal rate reached its highest at temperatures of 22℃, 24℃, and 26℃, reaching 15.25%, 16.18%, and 17.35%, respectively, at 300 μg / m³. 3 The worst were only 12.22%, 12.77%, and 13.20%.

[0066] 7. Scanning electron microscopy (SET) analysis results are shown in [reference needed]. Figure 8 The results showed that untreated raw Forsythia (A) had few surface pores and significant shadowing, which is not conducive to PM adsorption. 10 After optimization, the surface structure of Forsythia suspensa (B) became significantly looser, with a richer distribution of wrinkles and pores, indicating extremely strong adsorption properties. Forsythia suspensa (C), after adsorption experiments, had a smooth and flat surface with fewer wrinkles, demonstrating that PM adsorption was effective. 10 The particles filled the pores and folds on the surface of the forsythia.

[0067] 8. The results of the Fourier Transmission Infrared (FTIR) spectroscopy analysis are shown below. Figure 9 The results showed that the peak was 3381.66 cm. -1 A distinct hydroxyl (-OH) stretching vibration peak appears on both sides, with a relatively broad peak shape. The peak is at 1740.67 cm⁻¹. -1 The presence of relatively sharp peaks on both sides indicates that the sample may contain carbonyl groups. Peak 1043.43 cm⁻¹ -1 The left and right sides are mainly related to CO stretching vibration.

[0068] 9. Sample parameters were obtained using a BET instrument, as shown in Table 7. The results show that the specific surface area and pore volume of the original and optimized Forsythia changed. Increased pore volume and pore size had a significant impact on PM2.5 levels. 10 It has a good adsorption effect, proving that Forsythia has a multi-site high-efficiency adsorption function.

[0069] Table 7. Results of Specific Surface Area and Pore Size Parameter Analysis

[0070] 10. The results of elemental content analysis are shown in Table 8. The results show that the original Forsythia, the optimized Forsythia, and the Forsythia after adsorption contain multiple elements such as N, C, H, and S, among which C and H are the most abundant, while the contents of N and S decrease.

[0071] Table 8 Elemental Analysis Table

[0072] 11. The relationship between temperature and adsorption capacity is shown in the graph. Figure 10 ,Will Figure 10 The data were fitted with thermodynamic formulas, and the results are shown in [the table]. Figure 11 Modified Forsythia suspensa adsorbs PM 10 Thermodynamic parameters are shown in Table 9. The results show that ΔH0 > 0, indicating an endothermic process where increasing temperature promotes the reaction; ΔG0 < 0, indicating the adsorption process is spontaneous; and ΔS0 > 0, indicating the adsorption process conforms to the principle of entropy increase, and the system's disorder increases. The thermodynamic fitting equation for temperature T on lnKc is y = -14.7775x + 3.54841, R... 2 =0.91893, close to 1, indicating that the adsorption process fits the thermodynamic laws well. 500 μg / m 3 PM 10 After 24 hours of adsorption, the concentration decreased to 106 μg / m³. 3 It meets the national secondary standard of 150 μg / m 3 .

[0073] Table 9. Modified Forsythia suspensa adsorbs PM 10 Thermodynamic parameters

[0074] 12. Plot the adsorption kinetics curve with adsorption capacity q (μg / g) against adsorption time t (min), see... Figure 12 Using pseudo-first-order and pseudo-second-order dynamic equations to... Figure 12 The data was fitted, see Figure 13 and Figure 14 The results show that at a room temperature of 22 ℃, the pseudo-first-order rate equation y = 0.0157x + 0.2359, R 2 =0.9761; quasi-second-order rate equation y=0.1531x+0.5793, R 2 =0.9965. At 24 ℃, the pseudo-first-order rate equation y=0.0129x+0.1661, R 2 =0.9328; quasi-second-order rate equation y=0.1457x+0.5322, R 2 =0.9936. At 26 ℃, the pseudo-first-order rate equation y=0.0147x+0.2001, R 2 =0.9361; quasi-second-order rate equation y=0.1364x+0.4928; R 2 =0.9953.

[0075] As can be seen from Table 10, at different temperatures, the correlation coefficients of pseudo-second-order kinetic fitting are higher than those of pseudo-first-order kinetic fitting, indicating that the experimental process better conforms to the pseudo-second-order kinetic model. Based on the inference of the mechanism of action of the pseudo-second-order kinetic equation, the experiment is mainly dominated by chemical adsorption.

[0076] Table 10 Pseudo-first-order and pseudo-second-order reaction kinetic parameters

[0077] 13. The adsorption effect of optimized forsythia on PM 10 at different concentrations is shown in Figure 15 , and the data are fitted with Langmuir and Freundlich adsorption isotherm equations, as shown in Figure 15 . The results show that at room temperature of 22 °C, for the Langmuir equation y = 0.0972x + 39.7420, R Figures 16-17 = 0.9346; for the Freundlich equation y = 0.5514x - 0.7308, R 2 = 0.9509. At 24 °C, for the Langmuir equation y = 0.0966x + 36.9952, R 2 = 0.9519; for the Freundlich equation y = 0.5316x - 0.6623, R 2 = 0.9622. At 26 °C, for the Langmuir equation y = 0.0907x + 34.1881, R 2 = 0.9299; for the Freundlich equation y = 0.5433x - 0.6633; R 2 = 0.9366. 2

[0078] As can be seen from Table 11, the adsorption isotherms fitted by the two equations are both greater than 0.92, and both can well describe the adsorption process of forsythia on PM 10 . Among them, the isotherm fitted by the Freundlich equation is more consistent with the experimental data, and the experiment tends to a multi-layer adsorption mode. When 0.1 < n < 0.5, it is beneficial for adsorption, and when 1 / n > 2, it is difficult for adsorption. During the fitting process, 1 / n is less than 2, indicating that the adsorption behavior is relatively conducive to occurrence.

[0079] Table 11 Langmuir and Freundlich isotherm parameters for forsythia to adsorb PM 10

[0080] 14. Under the conditions of room temperature of 23 °C and humidity of 51 %RH, compare the removal effects of the optimal forsythia residue and other materials on PM 10 , and the results are shown in Figure 18The results showed that the F-test revealed highly significant differences at the 1% level in the interactions between different adsorbents, different adsorption times, and different material-time relationships (F1). 材料 = 275.5208, P=0.0001<0.01; F 时间 = 27.862, P=0.0001<0.01; F 材料×时间 =24.133, P=0.0001<0.01), the optimal residue of Forsythia suspensa for PM 10 The removal rate of this material is significantly better than other adsorbents at the 1% level, namely, optimized Forsythia suspensa residue > activated carbon > bamboo charcoal > diatomaceous earth > AB-8 macroporous adsorption resin > original Forsythia suspensa residue. Therefore, optimized Forsythia suspensa residue has a significantly better removal rate than other adsorbents at the 1% level. 10 They have a clear advantage in this regard, as shown in Tables 12 and 13 for specific data.

[0081] Table 12 Analysis of Variance Table (Duncan's Method)

[0082] Table 13 Effects of different materials on PM 10 The effect of adsorption (Duncan method)

[0083] 15. Desorption and regeneration results are shown in [reference needed]. Figure 19 The results showed that as the number of desorption cycles of the Forsythia suspensa adsorbent increased, the adsorbent's effect on PM2.5 decreased. 10 The removal rate also decreased, with the removal rate in the first 6 desorption experiments all above 10% (F=135.591, P=0.0001<0.01). After 8 desorption cycles, the Forsythia suspensa adsorbent still retained some removal capacity and could be recycled.

[0084] In summary, this invention uses Forsythia suspensa branches as raw material and modifies them through four methods. The optimal method was determined to be citric acid-assisted ethyl acetate modification, which was further optimized using a quadratic regression orthogonal rotational combination. At an ethyl acetate concentration of 0.17 mol / L and a citric acid concentration of 0.07 mol / L, after soaking for 29.1 h, the predicted Ymax was 15.67%, and the measured Y was 15.58%. The actual value / model optimum value was 0.994, which is basically consistent with the model. The Forsythia suspensa adsorbent was added at a particle size of 40 mesh and an amount of 2 g, with PM... 10 Initial concentration 400 μg / m 3 At an adsorption time of 40 min, a temperature of 24 ℃, and a humidity of 55%RH, the modified Forsythia suspensa showed good adsorption performance against PM2.5. 10The removal rate was the highest. Structural characterization revealed that the treated Forsythia had a large specific surface area and a loose, porous surface, providing excellent adsorption conditions. During adsorption, -OH groups and other functional groups played a role; the adsorption process better conformed to pseudo-second-order kinetics and the Freundlich isotherm. 500 μg / m 3 PM 10 After 24 hours of adsorption, the concentration decreased to 106 μg / m³. 3 It meets the national secondary standard of 150 μg / m 3 Modified Forsythia suspensa on PM 10 The adsorption effect at the 1% level is significantly better than activated carbon (granules), bamboo charcoal, diatomaceous earth, and AB-8 macroporous resin. Even after 8 desorption cycles, the Forsythia adsorbent still effectively adsorbs PM2.5. 10 It has a certain removal effect.

[0085] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A type of Forsythia PM 10 Adsorbent, characterized in that, Preparation of the Forsythia PM 10 The method for using adsorbents includes the following steps: The waste forsythia was boiled and then soaked in a citric acid solution with a concentration of 0.07 mol / L. The soaked forsythia waste was soaked in ethyl acetate solution for 29.1 h to obtain modified forsythia waste; the concentration of the ethyl acetate solution was 0.17 mol / L. The modified Forsythia waste was dried and then pulverized to obtain Forsythia PM. 10 Adsorbent.

2. The Forsythia PM according to claim 1 10 Adsorbent, characterized in that, The powder is pulverized through a 40-mesh sieve, and the material passing through the sieve is the Forsythia PM. 10 Adsorbent.

3. The Forsythia PM according to claim 1 10 Adsorbent, characterized in that, The waste from decocting Forsythia suspensa was soaked in citric acid solution for 30 minutes.

4. The Forsythia PM according to claim 1 or 3 10 Adsorbent, characterized in that, The forsythia waste includes dead forsythia branches.

5. The Forsythia PM according to claim 1 10 Adsorbent, characterized in that, The drying temperature is 80°C.

6. The Forsythia PM according to any one of claims 1 to 5 10 Adsorbents adsorb PM 10 Applications in [the context of the text].

7. The application according to claim 6, characterized in that, The Forsythia PM 10 Adsorbents adsorb PM 10 The ambient temperature was 24℃ and the humidity was 55%RH.

8. The application according to claim 6, characterized in that, The Forsythia PM 10 Adsorbents adsorb PM 10 The adsorption time was 40 min.

9. The application according to claim 6, characterized in that, The Forsythia PM 10 Adsorbents adsorb PM 10 PM 10 Concentration ≤400 μg / m 3 .

10. The application according to claim 6, characterized in that, Forsythia PM 10 The ratio of adsorbent to adsorption space is 2g:1m 3 .

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