White spirit vinasse activated carbon as well as preparation method and application thereof

Abstract

The invention relates to the technical field of activated carbon, in particular to white spirit vinasse activated carbon and a preparation method and application thereof. The preparation method of the white spirit vinasse activated carbon comprises the following steps: carbonizing and drying white spirit vinasse powder to obtain pretreated vinasse carbon powder; and adding ZnCl2 into the pretreated vinasse carbon powder for activation, and calcining to obtain the ZnCl2 activated vinasse activated carbon. The invention provides ZnCl2 activated vinasse activated carbon. Risk factors such as methanol, acetaldehyde and higher alcohols can be reduced under the condition that the loss of flavor compounds is relatively small. The method solves the problem of large loss of flavor compounds in the process of adsorbing risk factors by active carbon for wine, and fills the blank in the research field of vinasse active carbon adsorption of risk factors (methanol, acetaldehyde and fusel oil) in wine.

Description

Technical Field

[0001] The invention relates to the technical field of activated carbon, and in particular to a white wine lees activated carbon and a preparation method and application thereof. Background Art

[0002] As society progresses and develops, liquor plays an increasingly critical role in cultural, social, and ritual activities. As a result, more and more attention is being paid to assessing the safety of liquor. For the sake of liquor safety, it is necessary to develop a rapid, efficient, and cost-effective method to effectively mitigate the impact of risk factors (methanol, acetaldehyde, and fusel oil) present in liquor products.

[0003] The risk factor reduction method currently used by wineries is the wine activated carbon reduction method, which uses commercially available wine activated carbon. However, commercially available wine activated carbon has the following disadvantages: for some wines with rich flavor compounds, such as white wine, it cannot reduce risk factors such as methanol, acetaldehyde and higher alcohols while ensuring that the loss of flavor compounds is small.

[0004] At present, there are few studies on activated carbon from wine lees. Most of the studies focus on the wine lees obtained from beer production. There are few studies on the preparation of activated carbon from white wine lees (mainly composed of grains and rice husks), and most of them focus on gases (CO2) and heavy metals (Pb 2+ , Cd 2+ ) and there is no research on the adsorption of risk factors in wine using liquor lees. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a white wine lees activated carbon and a preparation method and application thereof, so as to solve the problem of large loss of flavor compounds in the process of adsorbing risk factors by activated carbon for wine.

[0006] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

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

[0008] The white wine lees powder is carbonized and dried to obtain pre-treated lees carbon powder; ZnCl2 is added to the pre-treated lees carbon powder for activation and calcination to obtain ZnCl2-activated lees activated carbon.

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

[0010] Further, the fine vinasse 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 with ultrapure water for multiple times and vacuum dried at 100°C overnight to obtain pretreated vinasse carbon powder.

[0011] Furthermore, 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.

[0012] Further, the mixture was mixed thoroughly and carbon activation was performed at room temperature and standard pressure for 8 hours.

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

[0014] Furthermore, the activated carbon is taken out after calcination and washed with ultrapure water; the solution is neutralized with dilute sodium hydroxide to pH=7, and then washed with ultrapure water for multiple times; the washed carbon is placed in a vacuum oven and dried at 100°C until it is water-free to obtain ZnCl2-activated wine lees activated carbon.

[0015] On the other hand, a method for using activated carbon from liquor lees in adsorbing methanol, acetaldehyde and fusel oil in liquor is provided.

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

[0017] The beneficial effects of the present invention are:

[0018] The present invention provides a ZnCl2 activated lees activated carbon, which can reduce risk factors such as methanol, acetaldehyde and higher alcohols while ensuring that the loss of flavor compounds is small. It solves the problem of large loss of flavor compounds in the process of adsorbing risk factors by activated carbon for wine, and fills the gap in the research field of adsorbing risk factors (methanol, acetaldehyde and fusel oil) in wine by activated carbon for lees. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The adsorption evaluation of risk factors, flavor compounds and ethanol by common commercial activated carbon for wine, common commodity activated carbon and ZnCl2 activated lees activated carbon in the examples is shown in the figure; (1) comparison of the reduction of each risk factor; (2) comparison of the adsorption ratio of higher alcohol / acid ester; (3) comparison of the adsorption ratio of acetaldehyde / acid ester; (4) comparison of the adsorption ratio of methanol / acid ester;

[0020] Figure 2The effect of ZnCl2 activated lees activated carbon on the different aromas of liquor at different adsorption times and concentrations in the examples; (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 lees activated carbon in the embodiment; wherein, (1) N2 adsorption isotherm curve of ZnCl2 lees activated carbon under different activation conditions; (2) DFT pore size distribution curve of ZnCl2 lees activated carbon under different activation conditions;

[0022] Figure 4 TEM and EDS images of pretreated lees carbon powder and ZnCl2-activated lees activated carbon in the embodiments; wherein, (1) TEM image of pretreated lees carbon powder; (2) C element distribution map of pretreated lees carbon powder; (3) O element distribution map of pretreated lees carbon powder; (4) TEM image of ZnCl2-activated lees activated carbon; (5) C element distribution map of ZnCl2-activated lees activated carbon; (6) O element distribution map of ZnCl2-activated lees activated carbon;

[0023] Figure 5 : is the charge density difference of different adsorption models in the embodiment (the green isosurface is the area where the charge density increases, and the blue isosurface is the area where the charge density decreases); wherein, (1) methanol; (2) acetaldehyde; (3) acetic acid; (4) ethyl acetate; (5) isoamyl alcohol;

[0024] Figure 6 Optimal adsorption configurations and localized orbital functions of risk factors and flavor compounds in the examples; wherein: (1) methanol; (2) acetaldehyde; (3) acetic acid; (4) ethyl acetate; and (5) isopentanol. DETAILED DESCRIPTION

[0025] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0026] Example

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

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

[0029] 2. After sufficient drying, remove non-particulate materials (such as insect carcasses, plastic debris, woven bag fibers) from the dried samples.

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

[0031] 4. The fine lees powder was placed in a ceramic crucible and carbonized at 400°C for 1 hour under a nitrogen atmosphere to obtain carbon powder.

[0032] 5. The carbon powder was washed three times with ultrapure water and then dried under vacuum at 100°C overnight to obtain pretreated wine lees carbon powder.

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

[0034] 7. The mixture was mixed thoroughly and then subjected to carbon activation at room temperature and standard pressure for 8 hours.

[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, take out the activated carbon and add ultrapure water to wash it.

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

[0038] 11. The washed carbon was placed in a vacuum oven and dried at 100°C until it was free of water to obtain ZnCl2 activated wine lees activated carbon (abbreviated as ZnCl2 activated carbon).

[0039] Test example

[0040] The specific implementation steps of the adsorption capacity evaluation test are as follows:

[0041] 1. Add 0.5% (m / v) ZnCl2 activated lees activated carbon prepared in Example to 25 mL of original liquor.

[0042] 2. Let it stand for 24 hours until adsorption is complete.

[0043] 3. The wine samples after adsorption were subjected to GC-MS analysis to evaluate the remaining methanol, acetaldehyde, fusel oil, ester compounds and acid compounds.

[0044] 4. Compare the remaining compounds after adsorption with the compounds 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 ester compounds), and calculate the amount of risk factor reduced for each equivalent of flavor compound lost.

[0046]

[0047] Each loss of one equivalent of flavor compounds removes

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

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

[0050] 2. The sensory evaluation panel consists of 10 well-trained sensory tasters aged 16-26.

[0051] 3. Place 20 mL of liquor in a professional tasting cup and add varying amounts of ZnCl2 to activate lees activated carbon.

[0052] 4. The sensory panelists scored the eight flavor profiles at different adsorption times.

[0053] 5. Count the flavor changes of liquor after adsorption.

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

[0055] Ordinary commercially available activated carbon for wine and ordinary commercial activated carbon were set up for comparison. The test results show that, without considering the loss of flavor components, ZnCl2-activated lees activated carbon has a better adsorption effect on acetaldehyde than activated carbon for wine and ordinary commercial activated carbon, while the adsorption effect on other compounds is poor. Compared with other international distilled spirits, white wine has the most flavor categories and the most complex flavors, so the loss of flavor compounds should also be considered when reducing risk factors. When considering reducing the loss of flavor compounds, ZnCl2-activated lees activated carbon performs much better than activated carbon for wine and ordinary commercial activated carbon ( Figure 1 ). ZnCl2 activated lees activated carbon has an excellent retention effect on acid compounds, which can minimize risk factors while ensuring less loss of flavor compounds. For each equivalent amount of acid compounds consumed, the efficiency of ZnCl2 activated lees activated carbon in reducing fusel oil is 2.91 times and 3.21 times that of wine activated carbon and commercial activated carbon, respectively, and the amount of acetaldehyde reduced is 7.06 times and 13.97 times that of wine activated carbon and commercial activated carbon, respectively.

[0056] The results of practical applications are as follows Figure 2 As shown in the figure, the addition amount of ZnCl2-activated lees activated carbon was inversely proportional to the aroma intensity of liquor. When the proportion of ZnCl2-activated lees activated carbon increased from 0.5% to 1%, the flavor characteristics of liquor decreased significantly. Within less than 2 hours of adsorption time, the aroma score of liquor stabilized at around 9 points, indicating that the effect of ZnCl2-activated lees activated carbon on the overall flavor of liquor was negligible. When the adsorption period exceeded 12 hours, the increase of malodorous elements could be felt in liquor. Therefore, the optimal adsorption parameters were determined as the adsorption time did not exceed 2 hours and the concentration of ZnCl2-activated lees activated carbon was kept below 0.15% (m / v). Under this parameter, the reduction efficiency of each risk factor was as follows: the content of acetaldehyde was reduced by 16.70±0.25%, and the content of higher alcohols was reduced by 17.68±1.87%. It is worth noting that the reduction rates of phenylethanol and isopentanol were the most significant, at 33.97% and 19.20%, respectively.

[0057] like Figure 3 As shown in Figure 2, the pore size distribution of ZnCl2-activated lees activated carbon is mainly between 0.7-1.5nm and 3-8nm, and the maximum nitrogen adsorption capacity is about 180cm 3 / g, this distribution type indicates that the number of micropores is dominant in the pore structure of the ZnCl2-activated carbon material. This figure also proves that the high adsorption efficiency of activated carbon is not necessarily suitable for the reduction of risk factors in distilled liquor, because high adsorption efficiency will also increase the adsorption rate of flavor components. Appropriate preparation conditions are the basis for maximizing the flavor components while reducing risk factors. The surface parameters of ZnCl2-activated lees activated carbon are shown in Table 1-2. The results show that the adsorption performance of lees carbon powder treated with ZnCl2 activation reagent is significantly improved. The specific surface area of ​​ZnCl2-activated lees activated carbon prepared under different conditions is 171.67-453.60m 2 / g. The activated carbon suitable for adsorption of risk factors in distilled liquor is not the activated carbon with the strongest adsorption capacity (largest specific surface area), but compared with activated carbon activated under other conditions, their microporous surface area accounts for the highest proportion of the total specific surface area, which is 80.80%. ZnCl2 activation can effectively increase the micropores on the surface of activated carbon. In practical applications, too high specific surface area will lead to the loss of esters and acidic compounds. The optimized ZnCl2-activated lees activated carbon has 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 of ZnCl2 activated lees activated carbon

[0061]

[0062] TEM and EDS images of pretreated lees carbon powder and ZnCl2 activated lees activated carbon are shown in Figure 2. Figure 4 As shown in the figure, the structure of the pretreated lees carbon powder is relatively compact, and the O element on the carbon surface is relatively sparse. However, the lees carbon powder activated by ZnCl2 becomes thinner and more porous, the C element is more concentrated, and the O element on the carbon surface is significantly increased and more concentrated.

[0063] Figure 5 The charge density difference of the optimal adsorption model for each compound is shown. In methanol adsorption, the area where the charge density decreases is mainly concentrated on the hydrogen atoms of the methanol methyl group and the hydroxyl oxygen atoms on the activated carbon surface, and intermolecular van der Waals adsorption occurs. When acetaldehyde is adsorbed, 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 does not change much. For the adsorption of acetic acid, Figure 5 As shown in the black box in (3), the charge density of the oxygen atoms on the carboxyl groups of acetic acid and the oxygen atoms on the surface carboxyl groups of activated carbon both increased, which resulted in the formation of a region with lower charge density between the two. The adsorption of ethyl acetate and acetic acid is similar, as shown in Figure 5 As shown in the red box in (4), the single-bonded oxygen atoms of ethyl acetate and the single-bonded oxygen atoms of the carboxyl groups on the surface of activated carbon both have high charge density, so a low-charge region is formed between them, which repel each other and inhibit adsorption. Isoamyl alcohol has a better adsorption effect, such as Figure 5 As shown in the orange box in (5), the charge density of hydrogen atoms on the hydroxyl group of isopentanol increases, which can interact with the carboxyl group -OH on the surface of activated carbon to form a bond, and the charge of the carbon atoms connected to the hydroxyl group of isopentanol is rearranged, which strengthens the charge transfer and bond formation. The adsorption site occurs on the oxygen-containing functional group, and ZnCl2 activation increases the oxygen-containing functional groups on the surface of the wine lees activated carbon.

[0064] In order to further verify the interaction between risk factors and flavor compounds and the surface of ZnCl2-activated lees activated carbon, the localized orbital localization functions of different adsorption configurations were calculated, such as Figure 6 As shown. In different adsorption configurations, the electrons on the -OH and -COOH functional groups on the ZnCl2-activated wine lees activated carbon and on the carbon atoms near the functional groups are delocalized to a certain extent. The strength of the delocalization represents the strength of the interaction between the electrons at the corresponding position and the adsorbate during adsorption. When the delocalized electrons interact with the higher and lower polarity parts of the adsorbed substance, they act as lone pairs of electrons at sites with positive adsorption potential or provide empty orbitals for sites with negative electrostatic potential to promote adsorption. Figure 6 In the adsorption of methanol, acetaldehyde and acetic acid shown in (1)-(3), the electrons on the activated carbon are delocalized to a large extent, which represents the diversity of adsorption sites. Figure 6In the case of ethyl acetate adsorption shown in (4), the electron delocalization range is small and the effect is weak. Figure 6 The adsorption of isoamyl alcohol shown in (5) has a large electron delocalization range and a 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, the present invention provides a ZnCl2 activated lees activated carbon, which can reduce risk factors such as methanol, acetaldehyde and higher alcohols while ensuring that the loss of flavor compounds is small. It solves the problem of large loss of flavor compounds in the process of adsorbing risk factors with activated carbon for wine, and fills the gap in the research field of adsorbing risk factors (methanol, acetaldehyde and fusel oil) in wine with activated carbon for lees.

[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 present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A method for preparing activated carbon from liquor lees, characterized in that: The following steps are involved: Carbonizing and drying liquor lees powder to obtain pretreated lees carbon powder; ZnCl2 is added to the pretreated vinasse carbon powder for activation and calcination to obtain ZnCl2 activated vinasse activated carbon.

2. The method for preparing activated carbon from liquor lees according to claim 1, characterized in that: The lees from different batches of liquor were collected, mixed thoroughly and dried under vacuum at 80°C, and the dried lees were crushed and passed through a 40-mesh sieve to obtain fine lees powder.

3. The method for preparing activated carbon from liquor lees according to claim 2, characterized in that: The fine vinasse 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 with ultrapure water for multiple times and vacuum dried at 100°C overnight to obtain pretreated vinasse carbon powder.

4. The method for preparing activated carbon from liquor lees according to claim 1, characterized in that: Add ZnCl2 and 25 mL of ultrapure water to the pretreated wine lees carbon powder at a mass ratio of ZnCl2:carbon powder = 2:1 and mix well.

5. The method for preparing activated carbon from liquor lees according to claim 4, characterized in that: The mixture was mixed thoroughly and carbon activation was performed at room temperature and standard pressure for 8 hours.

6. The method for preparing activated carbon from liquor lees according to claim 5, characterized in that: The carbon was washed and filtered, placed in a combustion boat, and calcined in a tube furnace at 900°C for 2 hours.

7. The method for preparing activated carbon from liquor lees according to claim 6, characterized in that: After calcination, the activated carbon is taken out and washed with ultrapure water; the solution is neutralized with dilute sodium hydroxide to pH=7, and then washed with ultrapure water for multiple times; and dried at 100°C until it is anhydrous to obtain ZnCl2-activated lees activated carbon.

8. A white wine lees activated carbon prepared by the method according to any one of claims 1 to 7.

9. Use of the white wine lees activated carbon according to claim 8 in adsorbing methanol, acetaldehyde and fusel oil in white wine.

10. The use according to claim 9, characterized in that: The adsorption time does not exceed 2 hours, and the concentration of ZnCl2 activated lees activated carbon is below 0.15% (m / v).

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