Baijiu vinasse activated carbon, and preparation method and application thereof

Abstract

The present application relates to the technical field of activated carbon, in particular to a kind of white spirit vinasse activated carbon and its preparation method and application.The preparation method of white spirit vinasse activated carbon includes the following steps: white spirit vinasse powder carbonization, drying, obtain pretreated vinasse carbon powder;ZnCl2 is added to pretreated vinasse carbon powder, and activated, calcined, to obtain ZnCl2 activated vinasse activated carbon.The present application provides a kind of ZnCl2 activated vinasse activated carbon, can reduce methanol, acetaldehyde and higher alcohol and other risk factors in the case of ensuring that the loss of flavor compounds is small.Solved the problem that flavor compounds are lost more in the process of adsorbing risk factors by activated carbon for wine, filled the research field blank of vinasse activated carbon adsorbing risk factors (methanol, acetaldehyde and fusel oil) in wine.

Description

Technical Field

[0001] This invention relates to the field of activated carbon technology, specifically to activated carbon from liquor lees, its preparation method, and its application. Background Technology

[0002] With societal progress and development, baijiu (Chinese liquor) plays an increasingly crucial role in cultural, social, and ceremonial activities. Consequently, greater attention is being paid to assessing the safety of baijiu. To ensure the safety of baijiu, it is necessary to develop a rapid, efficient, and cost-effective method to mitigate the impact of risk factors (methanol, acetaldehyde, and fusel oils) present in baijiu products.

[0003] Currently, the risk factor reduction method used by wineries is the activated carbon reduction method, which uses commercially available activated carbon for winemaking. However, commercially available activated carbon for winemaking has the following drawbacks: for some types of alcoholic beverages with high content of flavor compounds, such as baijiu, it cannot reduce risk factors such as methanol, acetaldehyde, and higher alcohols while ensuring minimal loss of flavor compounds.

[0004] Currently, research on activated carbon from brewing lees is limited. Most studies focus on lees obtained from beer production, with less research on activated carbon preparation from baijiu (Chinese liquor) lees (mainly composed of grains and rice husks), and those studies primarily focus on gases (CO2) and heavy metals (Pb). 2+ Cd 2+ The study did not use the adsorption of risk factors in liquor by baijiu lees. Summary of the Invention

[0005] In view of the above-mentioned shortcomings in the prior art, the purpose of this invention is to provide activated carbon from liquor lees, its preparation method and application, so as to solve the problem of significant loss of flavor compounds in the process of adsorbing risk factors by activated carbon for liquor.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0007] On the one hand, a method for preparing activated carbon from liquor lees is provided, which includes the following steps:

[0008] The baijiu lees powder is carbonized and dried to obtain pretreated lees carbon powder; ZnCl2 is added to the pretreated lees carbon powder for activation and calcination to obtain ZnCl2 activated lees activated carbon.

[0009] Furthermore, the lees from different batches of baijiu were collected, thoroughly mixed, and vacuum dried at 80°C. The dried lees were then pulverized and passed through a 40-mesh sieve to obtain fine lees powder.

[0010] Further, the fine distiller's grains powder was placed in a ceramic crucible and carbonized at 400°C for 1 hour under a nitrogen atmosphere to obtain carbon powder; the carbon powder was washed multiple times with ultrapure water and vacuum dried overnight at 100°C to obtain pretreated distiller's grains carbon powder.

[0011] Further, ZnCl2 and 25 mL of ultrapure water were added to the pretreated distiller's grains carbon powder at a mass ratio of ZnCl2:carbon powder = 2:1 and mixed evenly.

[0012] Furthermore, the mixture was thoroughly mixed and carbon activated for 8 hours at room temperature and standard atmospheric pressure.

[0013] Furthermore, after the carbon is washed and filtered, it is placed in a combustion boat and calcined in a tube furnace at 900°C for 2 hours.

[0014] Further, the activated carbon was removed after calcination and washed with ultrapure water; the solution was neutralized with dilute sodium hydroxide to pH=7, and then washed multiple times with ultrapure water; the washed carbon was placed in a vacuum oven and dried at 100℃ until anhydrous to obtain ZnCl2 activated distillers' grains activated carbon.

[0015] On the other hand, this invention provides the application of activated carbon from baijiu lees in adsorbing methanol, acetaldehyde, and fusel oil in baijiu.

[0016] Furthermore, the adsorption time does not exceed 2 hours, and the concentration of ZnCl2-activated activated carbon from distiller's grains is below 0.15% (m / v).

[0017] The beneficial effects of this invention are as follows:

[0018] This invention provides a ZnCl2-activated activated carbon for distiller's grains, which can reduce risk factors such as methanol, acetaldehyde, and higher alcohols while minimizing the loss of flavor compounds. It solves the problem of significant flavor compound loss during the adsorption of risk factors by activated carbon used in the distiller's grains, filling a gap in research on the adsorption of risk factors (methanol, acetaldehyde, and fusel oils) in distiller's grains using activated carbon. Attached Figure Description

[0019] Figure 1 The adsorption evaluation of risk factors, flavor compounds and ethanol by ordinary commercially available activated carbon for wine, ordinary commercial activated carbon and ZnCl2 activated lees in the examples; among which, (1) comparison of the reduction of each risk factor; (2) comparison of the adsorption ratio of higher alcohols / esters; (3) comparison of the adsorption ratio of acetaldehyde / esters; (4) comparison of the adsorption ratio of methanol / esters;

[0020] Figure 2The effect of ZnCl2-activated activated carbon on different aromas of baijiu under different adsorption times and concentrations is shown in the example; where (1) 0.05% m / v; (2) 0.15% m / v; (3) 0.25% m / v; (4) 0.50% m / v; (5) 1.00% m / v;

[0021] Figure 3 The surface model of ZnCl2 activated carbon from distiller's grains is shown in the example; (1) N2 adsorption isotherm curves of ZnCl2 activated carbon from distiller's grains under different activation conditions; (2) DFT pore size distribution curves of ZnCl2 activated carbon from distiller's grains under different activation conditions.

[0022] Figure 4 The images shown are TEM and EDS images of pretreated distillers' grains carbon powder and ZnCl2-activated distillers' grains activated carbon in the examples; wherein, (1) TEM image of pretreated distillers' grains carbon powder; (2) C element distribution map of pretreated distillers' grains carbon powder; (3) O element distribution map of pretreated distillers' grains carbon powder; (4) TEM image of ZnCl2-activated distillers' grains activated carbon; (5) C element distribution map of ZnCl2-activated distillers' grains activated carbon; (6) O element distribution map of ZnCl2-activated distillers' grains activated carbon.

[0023] Figure 5 The charge density difference of different adsorption models in the examples is shown (green isosurfaces represent regions with increasing charge density, and blue isosurfaces represent regions with decreasing charge density); where (1) methanol; (2) acetaldehyde; (3) acetic acid; (4) ethyl acetate; (5) isoamyl alcohol;

[0024] Figure 6 The optimal adsorption configuration and localized orbital function of the risk factor and flavor compound in the examples are: (1) methanol; (2) acetaldehyde; (3) acetic acid; (4) ethyl acetate; (5) isoamyl alcohol. Detailed Implementation

[0025] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0026] Example

[0027] The specific steps for preparing activated carbon from baijiu lees are as follows:

[0028] 1. Collect the lees from different batches of baijiu, mix them thoroughly, and dry them in a vacuum oven at 80℃.

[0029] 2. After thorough drying, remove non-particulate materials (such as insect carcasses, plastic fragments, and woven bag fibers) from the dried sample.

[0030] 3. Crush the dried distiller's grains and pass them through a 40-mesh sieve to obtain fine distiller's grains powder.

[0031] 4. Place the fine distiller's grains powder in a ceramic crucible and carbonize it at 400°C for 1 hour under a nitrogen atmosphere to obtain carbon powder.

[0032] 5. Wash the toner three times with ultrapure water, and then vacuum dry it overnight at 100°C to obtain pretreated distillers' grains toner.

[0033] 6. Accurately weigh 5g of pretreated distillers' grains carbon powder after carbonization, add ZnCl2 and 25mL of ultrapure water to the pretreated distillers' grains carbon powder at a mass ratio of 2:1 (m / m) and mix well.

[0034] 7. Mix the mixture thoroughly, and then perform carbon activation for 8 hours at room temperature and standard atmospheric pressure.

[0035] 8. After the carbon is washed and filtered, it is placed in a combustion boat and calcined in a tube furnace at 900°C for 2 hours.

[0036] 9. After calcination, remove the activated carbon and wash it with ultrapure water.

[0037] 10. Neutralize the solution with dilute sodium hydroxide to pH 7, and then wash it 5 times with ultrapure water.

[0038] 11. Place the washed carbon in a vacuum oven and dry it at 100°C until it is anhydrous to obtain ZnCl2 activated lees activated carbon (ZnCl2 activated carbon for short).

[0039] Test case

[0040] The specific implementation steps for the adsorption capacity assessment test are as follows:

[0041] 1. Add 0.5% (m / v) of the ZnCl2-activated charcoal prepared in the example to 25 mL of raw baijiu.

[0042] 2. Let stand for 24 hours to allow adsorption to complete.

[0043] 3. Perform GC-MS analysis on the wine sample after adsorption to evaluate the remaining methanol, acetaldehyde, fusel oil, ester compounds and acid compounds.

[0044] 4. Compare the remaining adsorbed compounds with those in the original wine sample and calculate the reduction rate.

[0045] 5. Record the reduction rates of risk factors (methanol, acetaldehyde, and fusel oil) and flavor compounds (acids and esters), and calculate the amount of risk factor reduced for each equivalent of flavor compound lost.

[0046]

[0047] The amount of flavor compound removed per equivalent lost

[0048] The specific implementation steps for the practical application condition evaluation test are as follows:

[0049] 1. Control the sensory evaluation temperature at 20±1℃.

[0050] 2. A sensory evaluation panel consisting of 10 trained sensory evaluators aged 16-26.

[0051] 3. Place 20mL of baijiu in a professional tasting glass and add varying amounts of ZnCl2 to activate the charcoal in the lees.

[0052] 4. The sensory evaluation team scored the product on eight flavor profiles at different adsorption times.

[0053] 5. Statistical analysis of the flavor changes of baijiu after adsorption.

[0054] After finding the optimal activated carbon addition amount and adsorption time, GC-MS was used to calculate the risk factor reduction rate of the liquor under optimal conditions and evaluate the adsorption results.

[0055] Ordinary commercially available activated carbon for spirits and ordinary commercial activated carbon were used as comparisons. The experimental results showed that, without considering the loss of flavor components, ZnCl2-activated activated carbon for spirits exhibited better adsorption of acetaldehyde compared to both spirits-grade activated carbon and ordinary commercial activated carbon, while its adsorption of other compounds was poor. Compared to other international distilled spirits, baijiu (Chinese white liquor) has the most diverse and complex flavor profiles; therefore, the loss of flavor compounds should also be considered when mitigating risk factors. When considering the reduction of flavor compound loss, ZnCl2-activated activated carbon for spirits showed significantly better performance than spirits-grade activated carbon and ordinary commercial activated carbon. Figure 1 ZnCl2-activated distillery lees activated carbon exhibits excellent retention of acidic compounds, minimizing risk factors while ensuring minimal loss of flavor compounds. For the same amount of acidic compounds consumed, ZnCl2-activated distillery lees activated carbon is 2.91 times more efficient at reducing fusel oils than distillery-grade activated carbon and 3.21 times more efficient than commercially available activated carbon, and it reduces acetaldehyde by 7.06 times and 13.97 times more efficient than distillery-grade activated carbon and commercially available activated carbon, respectively.

[0056] For the results of practical applications, such as Figure 2As shown, the amount of ZnCl2-activated activated carbon added is inversely proportional to the aroma intensity of baijiu (Chinese liquor). When the proportion of ZnCl2-activated activated carbon increases from 0.5% to 1%, the flavor characteristics of baijiu significantly decrease. Within an adsorption period of less than 2 hours, the aroma score of baijiu stabilizes at around 9 points, indicating that the effect of ZnCl2-activated activated carbon on the overall flavor of baijiu is negligible. When the adsorption period exceeds 12 hours, an increase in malodorous elements can be detected in the baijiu. Therefore, the optimal adsorption parameters are determined to be an adsorption time not exceeding 2 hours and a ZnCl2-activated activated carbon concentration maintained below 0.15% (m / v). Under these parameters, the reduction efficiencies of each risk factor are as follows: acetaldehyde content decreased by 16.70±0.25%, and higher alcohol content decreased by 17.68±1.87%. Notably, the reduction rates of phenylethanol and isoamyl alcohol were the most significant, at 33.97% and 19.20%, respectively.

[0057] like Figure 3 As shown, the pore size distribution of ZnCl2-activated activated carbon from distiller's grains is mainly between 0.7-1.5 nm and 3-8 nm, with a maximum nitrogen adsorption capacity of approximately 180 cm⁻¹. 3 The distribution pattern ( / g) indicates that micropores dominate the pore structure of ZnCl2-activated carbon materials. This figure also demonstrates that high adsorption efficiency of activated carbon is not necessarily suitable for reducing risk factors in distilled spirits, as high adsorption efficiency can also increase the adsorption rate of flavor components. Appropriate preparation conditions are fundamental to maximizing the preservation of flavor components while reducing risk factors. The surface parameters of ZnCl2-activated distillery lees activated carbon are shown in Tables 1-2. The results show that the adsorption performance of the distillery lees activated carbon powder treated with ZnCl2 activating reagent is significantly improved. The specific surface area of ​​ZnCl2-activated distillery lees activated carbon prepared under different conditions ranged from 171.67 to 453.60 m². 2 / g. While the activated carbon suitable for adsorbing risk factors in distilled spirits is not the activated carbon with the strongest adsorption capacity (largest specific surface area), it has the highest proportion of microporous surface area to total specific surface area (80.80%) compared to activated carbons activated under other conditions. ZnCl2 activation can effectively increase the micropores on the activated carbon surface. In practical applications, excessively high specific surface area can lead to the loss of esters and acidic compounds. Optimized ZnCl2-activated distillery lees activated carbon achieves a good balance between risk factor reduction and flavor component retention.

[0058] Table 1. Different activated carbon activation conditions for nitrogen adsorption and desorption characterization.

[0059]

[0060] Table 2 Characterization parameters of nitrogen adsorption and desorption on ZnCl2-activated distiller's grains activated carbon

[0061]

[0062] TEM and EDS images of pretreated distiller's grains activated carbon powder and ZnCl2-activated distiller's grains activated carbon are shown below. Figure 4 As shown, the pretreated distiller's grains carbon powder has a relatively compact structure, with sparse oxygen (O) on the carbon surface. In contrast, the distiller's grains carbon powder activated by ZnCl2 becomes thinner and more porous, with a more concentrated carbon (C) element, and a significantly increased and more concentrated O element on the carbon surface.

[0063] Figure 5 The charge density differences of the optimal adsorption models for each compound are shown. In methanol adsorption, the region of decreased charge density is mainly concentrated on the hydrogen atoms of the methanol methyl group and the hydroxyl oxygen atoms on the activated carbon surface, resulting in intermolecular van der Waals adsorption. In acetaldehyde adsorption, the charge density of the methyl hydrogen atoms decreases, while the charge density of the carbon atoms increases, and the charge density on the activated carbon surface remains relatively unchanged. For the adsorption of acetic acid, such as... Figure 5 As shown in the black box in section (3), the charge density of oxygen atoms on the carboxyl groups of acetic acid and on the carboxyl groups of activated carbon both increase, creating a region with lower charge density between them. The adsorption of ethyl acetate is similar to that of acetic acid, as... Figure 5 As shown in the red box in section (4), both the single-bonded oxygen atoms of ethyl acetate and the single-bonded oxygen atoms of the carboxyl groups on the activated carbon surface have high charge densities. Therefore, a low-charge region is formed between them, resulting in mutual repulsion and inhibiting adsorption. Isoamyl alcohol has a better adsorption effect, such as... Figure 5 As shown in the orange box in section (5), the charge density of hydrogen atoms on the hydroxyl group of isoamyl alcohol increases, which allows them to interact with the carboxyl-OH group on the surface of activated carbon to form a bond. Furthermore, the carbon atoms connected to the hydroxyl group of isoamyl alcohol undergo charge rearrangement, enhancing charge transfer and bond formation. The adsorption sites occur on oxygen-containing functional groups, and the activation of ZnCl2 increases the number of oxygen-containing functional groups on the surface of the activated carbon from distiller's grains.

[0064] To further verify the interaction between risk factors and flavor compounds and the surface of ZnCl2-activated distillers' grains activated carbon, localized orbital localization functions for different adsorption configurations were calculated, such as... Figure 6 As shown. In different adsorption configurations, electrons on the -OH and -COOH functional groups and the carbon atoms near these functional groups on ZnCl2-activated distillery waste activated carbon exhibit a certain degree of delocalization. The strength of this delocalization represents the strength of the interaction between the electrons at the corresponding positions and the adsorbate during adsorption. When delocalized electrons interact with the more polar and less polar portions of the adsorbate, they act as lone pairs, providing empty orbitals at sites with more positive adsorption potentials or sites with more negative electrostatic potentials, thus promoting adsorption. For example... Figure 6 As shown in (1)-(3), the adsorption of methanol, acetaldehyde, and acetic acid on activated carbon exhibits a large degree of electron delocalization, representing the diversity of adsorption sites. Figure 6The ethyl acetate adsorption shown in (4) has a small electron delocalization range and a weak effect. Figure 6 The adsorption of isoamyl alcohol shown in (5) has a large electron delocalization range and strong effect, which indicates that a large number of electrons can effectively interact with isoamyl alcohol during adsorption, thereby enhancing the adsorption effect of isoamyl alcohol.

[0065] In summary, this invention provides a ZnCl2-activated activated carbon from distiller's grains that can reduce risk factors such as methanol, acetaldehyde, and higher alcohols while minimizing the loss of flavor compounds. It solves the problem of significant flavor compound loss during the adsorption of risk factors by activated carbon used in winemaking, filling a gap in the research field of activated carbon from distiller's grains for adsorbing risk factors (methanol, acetaldehyde, and fusel oils) in wine.

[0066] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. The application of activated carbon from liquor lees in the adsorption of methanol, acetaldehyde, and fusel oils in liquor, characterized in that, The preparation method of activated carbon from baijiu lees includes the following steps: Baijiu lees powder was carbonized and dried to obtain pretreated lees carbon powder. ZnCl2 and 25 mL of ultrapure water were added to the pretreated lees carbon powder at a mass ratio of ZnCl2:carbon powder = 2:1 and mixed evenly. The mixture was thoroughly mixed and carbonized at room temperature and standard pressure for 8 hours. After the carbon was washed and filtered, it was placed in a combustion boat and calcined at 900℃ for 2 hours in a tube furnace to obtain ZnCl2 activated lees activated carbon.

2. The application according to claim 1, characterized in that, Collect the lees from different batches of baijiu, mix them thoroughly, and vacuum dry them at 80℃. Then, pulverize the dried lees and pass them through a 40-mesh sieve to obtain fine lees powder.

3. The application according to claim 2, characterized in that, Fine distiller's grains powder was placed in a ceramic crucible and carbonized at 400°C for 1 hour under a nitrogen atmosphere to obtain carbon powder. The carbon powder was washed multiple times with ultrapure water and vacuum dried overnight at 100°C to obtain pretreated distiller's grains carbon powder.

4. The application according to claim 1, characterized in that, After calcination, the activated carbon was removed and washed with ultrapure water. The solution was neutralized with dilute sodium hydroxide to pH=7, and then washed multiple times with ultrapure water. It was dried at 100℃ until anhydrous to obtain ZnCl2 activated distillers' grains activated carbon.

5. The application according to claim 1, characterized in that, The adsorption time should not exceed 2 hours, and the concentration of ZnCl2-activated activated carbon in distiller's grains should be below 0.15% (m / v).

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