CN115318257A - Preparation method of sauce-flavor wine vinasse-based porous carbon composite ionic liquid gas adsorbent - Google Patents

Abstract

The invention discloses a preparation method of a Maoxiang distiller's grains-based porous carbon composite ionic liquid gas adsorbent. The bulk solid waste of liquor brewing is used as a raw material, and is subjected to hydrofluoric acid removal pretreatment, high-temperature carbonization, and secondary treatment. Activated to obtain vinasse-based porous carbon with light specific gravity, developed microporous structure and high specific surface area. At the same time, the porous carbon was innovatively modified with proton-type ionic liquid to create a composite ionic liquid gas adsorbent based on Maotai wine lees-based porous carbon with higher thermal stability, thereby improving the adsorption of low-concentration gas by the lees-based porous carbon. capacity and separation selectivity, showing excellent adsorption and separation performance in the application of selective adsorption and separation of _CO2 , with ultra-high specific surface area, abundant pore structure properties and abundant active sites, with simple preparation method and easy operation , low cost and other advantages, it shows good industrial application prospects in the field of adsorption and separation of natural gas, biogas, low-concentration coalbed methane and coal-fired flue gas.

Description

Preparation of Maotai-flavor wine lees-based porous carbon composite ionic liquid gas adsorbent method

technical field

The invention relates to a preparation method of a Maotai-flavored wine lees-based porous carbon composite ionic liquid gas adsorbent, which belongs to the field of new chemical materials and gas separation.

Background technique

Gas adsorption separation is an important step in the purification process of various raw materials, and it is also an effective method to alleviate greenhouse gas emissions. Typical examples include natural gas purification, hydrogen production, biogas purification, ethanol and ammonia production, and gas separation from industrial combustion emission sources, among others. The main components of natural gas include 70-95% methane (CH ₄ ), the rest are acid gases such as carbon dioxide (CO ₂ ), hydrogen sulfide (H ₂ S), sulfur dioxide (SO ₂ ), ethane (C ₂ H ₆ ), propane (C ₃ H ₈ ) Gases such as light hydrocarbons. CO ₂ , SO ₂ , H ₂ S and other acid gases in natural gas are not conducive to storage and transportation, so they should be separated and enriched. On the one hand, it can reduce pipeline corrosion and increase the calorific value of natural gas; Physical utilization, chemical utilization and biological utilization provide basic resources. In addition, CO ₂ , SO ₂ , and H ₂ S also widely exist in low-concentration coalbed methane, methane, and industrial coal-fired flue gas. Direct emission will easily aggravate the greenhouse effect and cause waste of carbon resources. Faced with this type of low-concentration gas , Efficient selective gas capture is the only way to effectively utilize carbon resources. In industry, adsorption separation based on physical action has the advantages of low energy consumption, low equipment corrosion, easy regeneration, etc., and has broad application prospects in gas separation. Among the common solid adsorbents, the pressure swing physical adsorption of porous carbon materials has obvious convenience and energy-saving advantages in the separation of CO ₂ , H ₂ S and other gases. It can be operated under normal temperature and pressure. It can be regenerated and recycled under certain conditions.

Guizhou "Moutai" is well-known at home and abroad, and the annual output value of Maotai-flavored liquor exceeds 100 billion. However, the large amount of waste distiller's grains produced in the brewing process of Maotai-flavored liquor is currently mainly used for feed or organic fertilizer, with low utilization rate, and the large-scale utilization is limited due to poor environmental safety and reliability of the product and small processing capacity. Distiller's grain solid waste is rich in biomass, and biomass is low in cost and environmentally friendly. It is a renewable resource and has broad prospects for the preparation of biochar porous adsorbents. At present, the patent CN109835897B discloses a metal/heteroatom modified distiller's grain-based activated carbon and its preparation method. The distiller's grains, nitrogen-containing compounds and transition metal compounds are ground and mixed in a mortar, and then carbonized at 600-900°C for 1- 3h, soak the carbonized activated carbon in acid for 5-15h, and then activate it with _CO2 or water vapor at 700-900℃ for 2-5h to obtain metal/heteroatom modified distiller's grains-based activated carbon, and use it at room temperature Press down to catalyze persulfate oxidation to degrade organic pollutants such as acid red and methyl orange in water. Patent CN108975333A discloses a preparation method of modified distiller's grain-based activated carbon. Distiller's grain raw material is added to phosphoric acid solution and ultrasonically charged for 25-35 minutes. After drying, it is activated at 510-530°C for 2-3 hours, then soaked in NaOH solution for 4-6 hours, washed, After drying and grinding, add distiller's grain activated carbon to Fe(NO ₃ ) ₃ solution, add NaOH solution dropwise to pH 8.1-8.3, seal and stand for 71-73 hours to obtain hydroxyl iron modified distiller's grain-based activated carbon, and use it to remove water Congo red. Patent CN109928391A discloses a modified distiller's grain-based activated carbon and its preparation method. Distiller's grains are carbonized at 700-900°C for 3-5 hours, and then ultrasonically mixed with activators such as potassium hydroxide, potassium nitrate, potassium carbonate or sodium hydroxide. Hydrothermal reaction at 100-200°C to obtain activated carbon, then put the activated carbon into dicyandiamide, melamine, ammonium chloride or urea solution and carbonize at 850-950°C for 3-5 hours to obtain modified distiller's grains-based activated carbon, which can be used in organic wastewater Catalytic persulfate oxidative degradation of organic pollutants. Patent CN11210447A discloses a preparation method of rice wine distiller's grains-based activated carbon. Distiller's grains and hydrochloric acid solution are mixed to form a slurry, which is then hydrolyzed in a water bath at 100°C, and then carbonized at 400-600°C for 1-5 hours. Potassium chloride, potassium carbonate, zinc chloride and other activator solutions impregnated to obtain rice distiller's grains-based activated carbon. Patent CN113479879A discloses an activated carbon material based on secondary fermentation distiller's grains and its preparation method and application. The low-temperature pre-carbonized material and alkaline inorganic matter are directly mixed after the biomass is fermented twice, and then calcined to obtain the activated carbon material based on secondary fermentation. Activated carbon material of distiller's grains, and used as supercapacitor electrode material.

Existing patents mainly prepare distiller's grains into biomass-based activated carbon and catalyst carrier through hydrolysis, pyrolysis, physical activation, chemical activation or heteroatom modification, which are mainly used for the removal, degradation or degradation of organic pollutants in dyes and organic wastewater. supercapacitor material. At present, there is no clear technical route for preparing distiller's grain-based porous carbon materials for gas adsorption and separation using Maotai-flavored wine distiller's grains.

Contents of the invention

Aiming at the above technical problems, the present invention provides a preparation method technology of Maotai-flavored wine lees-based porous carbon composite ionic liquid gas adsorbent. The technical route recycles Maotai-flavored wine lees to prepare porous carbon gas with excellent performance. Adsorbents, and ionic liquids are used to modify the adsorbents. The prepared materials are of great development value for the normal temperature and pressure capture of low partial pressure gas recovery.

The technical scheme adopted in the present invention to prepare the Maotai-flavored wine distiller's grain-based porous carbon composite ionic liquid gas adsorbent is divided into three steps: (1) The Maotai-flavored wine distiller's grains are firstly treated with 0.5-2mol·L ^-1 hydrofluoric acid to remove impurities 12-24 hours, washed with a large amount of deionized water, dried, and crushed to 50-200 meshes, and then heated to 500°C at 5-10°C·min ^-1 under a nitrogen atmosphere with a nitrogen flow rate of 100-200ml·min ^-1 . Carbonize for 1-3 hours to obtain a porous carbon precursor; (2) Mix the above-mentioned porous carbon precursor and activator by mechanical ball milling according to a specific mass ratio, and then, under a nitrogen atmosphere with a nitrogen flow rate of ^50-100ml ·min 10°C·min ^-1 heated up to 600-800°C for secondary carbonization for 1-3 hours, washed with 0.1-0.5 mol·L ^-1 hydrochloric acid and deionized water until neutral, filtered, and dried to obtain Maotai-flavored wine lees-based porous (3) Add the above-mentioned Maotai-flavored wine lees-based porous carbon and ionic liquid into the solvent according to a specific mass ratio, wash with hexane, toluene or acetone, separate, and dry to obtain Maotai-flavored wine lees-based porous carbon composite ionic liquid gas Adsorbent.

In the above step (1), the main components of the Maotai-flavored wine lees include but are not limited to fermented sorghum, rice husk, wheat, and corn.

In the above step (2), the mass ratio of the porous carbon precursor to the activator is 1:0.5-3.

In the above step (2), the activator includes but not limited to KOH, K ₂ CO ₃ , KHCO ₃ , K ₃ PO ₄ , NaOH, H ₃ PO ₄ , ZnCl ₂ and NaNH ₂ .

In the above step (2), the mechanical ball milling time is 5-15 minutes.

In the above step (3), the mass ratio of the Maotai-flavored wine lees-based porous carbon to the ionic liquid is 1:0.1-1, and the modification methods include but not limited to impregnation, in-situ modification and chemical grafting.

In the above step (3), the ionic liquid is a carboxylate proton type ionic liquid.

In the above step (3), the organic amine structure required for the synthesis of the carboxylate proton ionic liquid includes but not limited to diethylenetriamine, tetraethylenepentamine, polyethyleneimine, and the carboxylate proton ion The polycarboxylic acid structures required for liquid synthesis include but are not limited to iminodiacetic acid, ethylenediamine-N,N'-diacetic acid, and nitrilotriacetic acid.

The advantages of the present invention are:

(1) The present invention "uses waste to treat waste", which can realize the resource utilization of Maotai-flavored distiller's grain solid waste, and the porous carbon composite ionic liquid gas adsorbent prepared at the same time can realize various gas source fields (natural gas, biogas, coal bed methane, combustion gas, etc.) High-efficiency capture and recovery of low-concentration gases in coal flue gas), and the adsorbent is easy to regenerate and recycle.

(2) The preparation method of the present invention is simple, is beneficial to industrial operation, and the prepared porous carbon composite ionic liquid gas adsorbent has high specific surface area, light specific gravity, well-developed microporous structure and abundant active sites.

(3) The porous carbon gas adsorbent prepared by the present invention exhibits good performance in gas adsorption and separation. Under normal pressure, it has good adsorption performance for CO ₂ , CH ₄ , H ₂ S, SO ₂ , etc., and the adsorption capacity is 5.20- 10.7 mmol/g.

(4) Distiller's grains-based porous carbon was obtained by pretreatment, pre-carbonization, and secondary activation of Maotai-flavored wine distiller's grains, a bulk solid waste from liquor brewing, and used for CO ₂ adsorption research. The distiller's grains are pretreated with hydrofluoric acid to remove ash such as metal oxides and silicon dioxide in the raw materials. Selecting 500°C/2h for pre-carbonization can effectively remove moisture, organic impurities, volatiles, etc. in distiller's grain raw materials, and provide high-quality porous carbon precursors for secondary activation. The mechanical ball milling method is beneficial to the control of the mechanical ball milling intensity, solid-solid mixing uniformity, and ball milling time during the physical mixing process.

(5) The present invention provides a method for preparing a porous carbon gas adsorbent by using bulk solid waste Maotai-flavored wine distiller's grains, which promotes the resource utilization of distiller's grains solid waste. At the same time, in order to improve the adsorption capacity and separation selectivity of traditional porous carbon, the present invention Utilizing the characteristic functional groups such as hydroxyl, carboxyl, and CO bonds contained in the distiller's grain-based porous carbon structure, as the action site of the ionic liquid modified porous carbon, it will have better acid gas adsorption capacity such as CO ₂ , H ₂ S , SO ₂ , heat Polycarboxylate protic ionic liquids with high stability and rich hydrogen bonding sites are immobilized on distillers grains-based porous carbon to promote the adsorption performance of distillers grains-based porous carbon for low-concentration greenhouse gases and realize efficient selection of basic carbon resources Sex capture separation.

(6) The present invention focuses on the influence of the following factors on the preparation and adsorption performance of distiller's grain porous carbon. First, the effect of the amount of activator on distiller's grain-based porous carbon was investigated. When the amount of KOH was small (<1 g), the number of ultramicropores (<1 nm) in distiller's grain-based porous carbon was large, especially the micropores in the range of 0.45-0.65 nm. The structure distribution is more, and the CO ₂ adsorption capacity under the corresponding normal pressure increases; on the contrary, the KOH dosage (>1g) increases, the specific surface area of the porous carbon increases significantly, and the number of mesopores and macropores increases, while the corresponding The _CO2 adsorption capacity decreases. Then, the effect of the type of activator on distiller's grain-based porous carbon was investigated. When the distiller's grain-based porous carbon was prepared with the same amount (0.5 g) and different activators, the porous carbon had a large number of microporous structures, but the specific surface area was relatively small. In contrast, the activation effect of KOH has a significant advantage, the specific surface area reaches 1059m ² /g, and the corresponding CO ₂ adsorption capacity is the largest under normal pressure; finally, the influence of the secondary activation temperature on the distiller's grain-based porous carbon was investigated, Mainly use 600-800°C for factor investigation. As the temperature rises, the specific surface area increases, but the number of micropores first increases and then decreases. When the activation temperature is 700°C, distiller's grain-based porous carbon has the largest micropores (< 1nm) quantity, corresponding to the largest CO ₂ adsorption capacity under normal pressure.

Description of drawings

Figure 1 is the SEM characterization diagram of the gas adsorbent prepared in different embodiments: Figure 1a is Example 1; Figure 1b is Example 2.

FIG. 2 is a TEM characterization diagram of the gas adsorbent prepared in Example 1.

Fig. 3 is the characterization diagram of the pore structure of the gas adsorbent prepared in Example 1: Fig. 3a is a nitrogen adsorption-desorption isotherm; Fig. 3b is a pore size distribution curve.

Fig. 4 is a schematic diagram of the synthesis route of [TEPAH][IDA] carboxylate proton-type ionic liquid in Example 3.

Figure 5 is a schematic diagram of the chemical grafting of [SCA-2H][OOCR] carboxylate proton-type ionic liquid in Example 4 based on distiller's grains porous carbon.

FIG. 6 is the CO ₂ , CH ₄ , and N ₂ gas adsorption curves of the gas adsorbent prepared in Example 1.

Fig. 7 is the gas adsorption curves of SO ₂ , H ₂ S and CO ₂ of the gas adsorbent prepared in Example 2.

Fig. 8 is the CO of gas adsorbent prepared by embodiment ₂ , embodiment 3, embodiment 4, embodiment 5 Gas adsorption curve, wherein embodiment 2: KOH-C-1; Embodiment 3: KOH-C-1 /[TEPAH][IDA] _0.2 ; Example 4: KOH-C-1/[SCA-2H][OOCR] _0.2 ; Example 5: KOH-C-1/[TEPAH][IDA] _0.5 .

Detailed ways

In terms of specific implementation process, the present invention focuses on the influence of the following factors on the preparation and adsorption performance of distiller's grain porous carbon. First, the effect of the amount of activator on the distiller's grain-based porous carbon was investigated. When the amount of KOH was small (<1g), the number of ultra-micropores (<1nm) in the distiller's grain-based porous carbon was large, especially the micropore structure in the range of 0.45-0.65 nm more distribution, the corresponding CO ₂ adsorption capacity under normal pressure increases; on the contrary, with the increase of KOH dosage (>1g), the specific surface area of porous carbon increases significantly, the number of mesopores and macropores increases, and the corresponding CO2 under normal pressure ₂ The adsorption capacity is reduced. Then, the effect of the type of activator on distiller's grain-based porous carbon was investigated. When using the same amount (0.5g) and different activators to prepare distiller's grain-based porous carbon, the porous carbon has a large number of microporous structures, but the specific surface area is relatively small. In contrast, the activation effect of KOH has a significant advantage, the specific surface area reaches 1059m ² /g, and the corresponding CO ₂ adsorption capacity is the largest under normal pressure; finally, the influence of the secondary activation temperature on the distiller's grain-based porous carbon was investigated, Mainly use 600-800°C for factor investigation. As the temperature rises, the specific surface area increases, but the number of micropores first increases and then decreases. When the activation temperature is 700°C, distiller's grain-based porous carbon has the largest micropores (< 1nm) quantity, corresponding to the largest CO ₂ adsorption capacity under normal pressure.

Example 1

A preparation method of Maotai-flavored wine lees-based porous carbon gas adsorbent. Stir and pretreat the dried distiller's grains in 2 mol·L ^-1 hydrofluoric acid solution for 24 hours, wash with deionized water, dry at 105°C, pulverize to 50-200 mesh, and then dissolve the distiller's grains in a nitrogen flow rate of 100ml·min ^-1 Under the maintained inert atmosphere, pre-carbonize the porous carbon precursor at 5°C·min ^-1 to 500°C for 2h; the porous carbon precursor and the KOH activator are mechanically ball milled for 10min at a mass ratio of 1:0.5, and then Under an inert atmosphere maintained at 50ml·min ^-1 , heat up to 700℃ at 5°C·min ^-1 for secondary carbonization for 2h, wash with 0.1mol·L ^-1 hydrochloric acid, then wash with deionized water until neutral, filter, 105 °C drying to obtain Maotai-flavored wine lees-based porous carbon gas adsorbent (KOH-C-0.5).

Characterize the microscopic morphology of the porous carbon gas adsorbent. It can be seen from SEM Figure 1a that irregular pores are formed on the surface of porous carbon. Further analysis from TEM Figure 2 shows that a large number of micropores similar to wormholes are formed in the adsorbent. structure, and are randomly distributed in the carbon skeleton. At the same time, the specific surface area and pore structure of the porous carbon gas adsorbent were characterized, and the results are shown in Figure 3. Among them, Fig. 3a is the nitrogen adsorption-desorption isotherm. According to the classification of adsorption isotherms by IUPAC, the curve belongs to type I. At lower relative pressure (P/P ₀ <0.1), _N2 has a larger adsorption capacity, And after the inflection point, it maintains a relative level in a wide relative pressure range (0.1<P/P ₀ <1.0), indicating that the adsorbent has a large number of microporous structures. It can also be seen from the pore size distribution curve in Figure 3b that the pore size of the adsorbent is mainly distributed in the 0.45 ~ 1nm. It can be seen from the analysis that the prepared Maotai-flavored wine lees-based adsorbent has a specific surface area of 1059 m ² /g, a total pore volume of 0.57 cm ³ /g, and a micropore volume of 0.50 cm ³ /g.

BSD-PM2 physical adsorption instrument was used to test the CO ₂ , CH ₄ , and N ₂ gas adsorption properties of the adsorbent. The adsorption curves are shown in Figure 6. Under the same conditions, the adsorption capacity varies greatly depending on the gas, and the order is CO ₂ >CH ₄ >N ₂ . Under the conditions of 273.15K and 1 bar, the CO ₂ adsorption capacity is 6.34 mmol/g, and the CO ₂ selectivity calculated by IAST competitive adsorption is 24.1% (1 bar, CO ₂ :N ₂ =15%:85%), 5.6% (1 bar, CO ₂ :CH ₄ =40%:60%).

Example 2

A preparation method of Maotai-flavored wine lees-based porous carbon gas adsorbent. Stir and pretreat the dried distiller's grains in 2 mol·L ^-1 hydrofluoric acid solution for 24 hours, wash with deionized water, dry at 105°C, pulverize to 50-200 mesh, and then dissolve the distiller's grains in a nitrogen flow rate of 100ml·min ^-1 Under the maintained inert atmosphere, pre-carbonize the porous carbon precursor at 5°C·min ^-1 to 500°C for 2h to obtain the porous carbon precursor; the porous carbon precursor and the KOH activator are mechanically ball milled for 15min at a mass ratio of 1:1, and then Under an inert atmosphere maintained at 100ml·min ^-1 , heat up to 700°C at 5°C·min ^-1 for secondary carbonization for 2h, wash with 0.1mol·L ^-1 hydrochloric acid, then wash with deionized water until neutral, filter, 105 °C to obtain Maotai-flavored wine lees-based porous carbon adsorbent (KOH-C-1).

Characterize the microscopic morphology of the porous carbon gas adsorbent. It can be seen from SEM Figure 1b that a large number of pore structures are formed in the adsorbent. The pore structure of the porous carbon gas adsorbent is characterized by analysis. It can be known that the pore size of the gas adsorbent mainly distributes At 0.45-3.5nm, the specific surface area is 2079m ² /g, the total pore volume is 1.14cm ³ ·g ^-1 , and the micropore volume is 0.94cm ³ ·g ^-1 .

BSD-PM2 physical adsorption instrument was used to test the adsorption performance of H ₂ S, SO ₂ , CO ₂ gas of the adsorbent, and the adsorption curve is shown in Fig. 7 . It can be seen from the figure that under the conditions of 273.15K and 1 bar, the adsorption capacity of H ₂ S is 6.68mmol·g ^-1 , that of SO ₂ is 9.52mmol·g ^-1 , and that of CO ₂ is 5.96mmol·g ^-1 .

Example 3

A preparation method of Maotai-flavored wine lees-based porous carbon composite ionic liquid gas adsorbent. Stir and pretreat the dried distiller's grains in a 2mol·L ^-1 hydrofluoric acid solution for 24 hours, wash with deionized water, dry at 105°C, pulverize to 50-200 mesh, and then maintain under nitrogen flow of 100ml·min ^-1 Under an inert atmosphere, the porous carbon precursor was pre-carbonized at 5°C·min ^-1 to 500°C for 2 hours; the porous carbon precursor and the KOH activator were mechanically ball milled for 15 minutes at a mass ratio of 1:1, and then Under an inert atmosphere maintained at min ^-1 , heat up to 700°C at 5°C min ^-1 for secondary carbonization for 2 hours, wash with 0.1mol·L ^-1 hydrochloric acid, then wash with deionized water until neutral, filter, 105°C Dried to obtain Maotai-flavored wine lees-based porous carbon adsorbent (KOH-C-1). At the same time, the organic amine and carboxylic acid are reacted in ethanol at a molar ratio of 1:2, and the ethanol is removed after the reaction. The ionic liquid is washed with hexane to remove unreacted amine or acid, and the carboxylate proton ionic liquid is obtained after vacuum drying. . For example: [TEPAH] [IDA] carboxylate proton type ionic liquid synthesis route is shown in Figure 4. Then, add distiller's grain-based porous carbon and [TEPAH][IDA] carboxylate proton-type ionic liquid into acetone at a mass ratio of 1:0.2, stir and impregnate fully, filter and dry to obtain distiller's grain-based porous carbon composite ionic liquid gas adsorbent (KOH-C-1/[TEPAH][IDA] _0.2 ).

Example 4

A preparation method of Maotai-flavored wine lees-based porous carbon composite ionic liquid gas adsorbent. Stir and pretreat the dried distiller's grains in a 2mol·L ^-1 hydrofluoric acid solution for 24 hours, wash with deionized water, dry at 105°C, pulverize to 50-200 mesh, and then maintain under nitrogen flow of 100ml·min ^-1 Under an inert atmosphere, the porous carbon precursor was pre-carbonized at 5°C·min ^-1 to 500°C for 2 hours; the porous carbon precursor and the KOH activator were mechanically ball milled for 15 minutes at a mass ratio of 1:1, and then Under an inert atmosphere maintained at min ^-1 , heat up to 700°C at 5°C min ^-1 for secondary carbonization for 2 hours, wash with 0.1mol·L ^-1 hydrochloric acid, then wash with deionized water until neutral, filter, 105°C Dried to obtain Maotai-flavored wine lees-based porous carbon adsorbent (KOH-C-1). At the same time, through acid-base neutralization reaction, organic amine and carboxylic acid are mixed at a molar ratio of 1:2 to synthesize a variety of primary amines, tertiary amines, silane coupling agents, hydroxyl or ether bond-containing products with characteristic structures Carboxylate protic ionic liquid. Then, distiller's grain-based porous carbon and ionic liquid were added into toluene at a mass ratio of 1:0.2 to reflux, and the distiller's grain-based porous carbon composite ionic liquid gas adsorbent was prepared by chemical grafting. For example: chemical grafting of [SCA-2H][OOCR] carboxylate proton type ionic liquid on vinasse-based porous carbon, the synthesis route of KOH-C-1/[SCA-2H][OOCR] _0.2 is shown in Figure 5.

Example 5

A preparation method of Maotai-flavored wine lees-based porous carbon composite ionic liquid gas adsorbent. Stir and pretreat the dried distiller's grains in a 2mol·L ^-1 hydrofluoric acid solution for 24 hours, wash with deionized water, dry at 105°C, pulverize to 50-200 mesh, and then maintain under nitrogen flow of 100ml·min ^-1 Under an inert atmosphere, the porous carbon precursor was pre-carbonized at 5°C·min ^-1 to 500°C for 2 hours; the porous carbon precursor and the KOH activator were mechanically ball milled for 15 minutes at a mass ratio of 1:1, and then Under an inert atmosphere maintained at min ^-1 , heat up to 700°C at 5°C min ^-1 for secondary carbonization for 2 hours, wash with 0.1mol·L ^-1 hydrochloric acid, then wash with deionized water until neutral, filter, 105°C Dried to obtain Maotai-flavored wine lees-based porous carbon adsorbent (KOH-C-1). At the same time, the organic amine and carboxylic acid are reacted in ethanol at a molar ratio of 1:2, and the ethanol is removed after the reaction. The ionic liquid is washed with hexane to remove unreacted amine or acid, and the carboxylate proton ionic liquid is obtained after vacuum drying. . Then, add distiller's grain-based porous carbon and [TEPAH][IDA] carboxylate proton-type ionic liquid into acetone at a mass ratio of 1:0.5, stir and impregnate fully, filter and dry to obtain distiller's grain-based porous carbon composite ionic liquid gas adsorbent (KOH-C-1/[TEPAH][IDA] _0.5 ).

Example 6

The _CO2 adsorption performance of the gas adsorbent prepared in Example 2, Example 3, Example 4 and Example 5 was tested by BSD-PM2 physical adsorption instrument, and the adsorption curve is shown in Figure 8. It can be seen from the figure that under the conditions of 273.15 K and 1 bar, the adsorption capacity of KOH-C-1 is 5.96 mmol·g ^-1 , the adsorption capacity of KOH-C-1/[TEPAH][IDA] _0.2 is 8.85 mmol·g ^-1 , The adsorption capacity of KOH-C-1/[SCA-2H][OOCR] _0.2 is _7.79mmol ·g ^-1 . 10.7 mmol·g ^-1 .

The method of the present invention starts from the utilization of solid waste as a resource, and uses Maotai-flavored wine distiller's grains as a large solid waste from liquor brewing as a raw material, and undergoes impurity removal pretreatment with hydrofluoric acid, high-temperature carbonization, and secondary activation to obtain light specific gravity and developed microporous structure Distiller's grains-based porous carbon with a specific surface area of 3657.6m ² ·g ^-1 , under normal pressure, the adsorption capacity of CO ₂ is 6.34mmol·g ^-1 , the adsorption capacity of H ₂ S is 6.68mmol·g ^-1 , and the adsorption capacity of SO ₂ is 9.52mmol • g ⁻¹ . At the same time, the porous carbon is innovatively modified with proton-type ionic liquids to create a more thermally stable Maotai-flavor wine distiller's grain-based porous carbon composite ionic liquid gas adsorbent, thereby improving the adsorption of distiller's grain-based porous carbon to low-concentration gases capacity and separation selectivity. The Maotai-flavored wine lees-based porous carbon composite ionic liquid gas adsorbent prepared by the present invention exhibits excellent adsorption and separation performance in the selective adsorption and separation of _CO2 , and the _CO2 adsorption capacity is increased to 10.7mmol· g ^-1 . Because the prepared porous carbon composite ionic liquid gas adsorbent has the advantages of super high specific surface area, rich pore structure properties and abundant active sites, the preparation method is simple, easy to operate, and low cost (approximately wood chips commercial activated carbon 87% of the cost), making it show a good industrial application prospect in the fields of gas adsorption and separation of natural gas, biogas, low-concentration coal bed methane and coal-fired flue gas.

Claims (8)

1. A preparation method of a sauce-flavor wine vinasse-based porous carbon composite ionic liquid gas adsorbent is characterized by comprising the following steps of:

(1) 0.1-0.5 mol/L of sauce-flavor wine vinasse is firstly used ^-1 Removing impurities with hydrofluoric acid for 0.5-2 h, washing with deionized water, filtering, drying, pulverizing to 50-200 meshes, and introducing nitrogen at 100-200 ml/min ^-1 Under the nitrogen atmosphere at 5-10 ℃ for min ^-1 Heating to 500 ℃ for pre-carbonization for 1-3 h to obtain a porous carbon precursor;

(2) The porous carbon precursor and the activating agent are mechanically ball-milled and mixed according to a specific mass ratio, and then the flow is 50-100 ml.min ^-1 Under the nitrogen atmosphere at 5-10 ℃ for min ^-1 The temperature is raised to 600 to 800 ℃ at the temperature raising speed, secondary carbonization treatment is carried out for 1 to 3 hours, and then the secondary carbonization treatment is carried out for 0.1 to 0.5 mol.L ^-1 Washing the mixture with hydrochloric acid and deionized water to be neutral, filtering and drying to obtain the sauce-flavor wine vinasse-based porous carbon;

(3) The sauce-flavored wine vinasse-based porous carbon is compounded with ionic liquid according to specific mass, and then the sauce-flavored wine vinasse-based porous carbon composite ionic liquid gas adsorbent is obtained.

2. The preparation method of the sauce-flavored wine lees-based porous carbon composite ionic liquid gas adsorbent according to claim 1, wherein the main components of the sauce-flavored wine lees include, but are not limited to, fermented sorghum, rice hulls, wheat and corn.

3. The preparation method of the ionic liquid gas adsorbent compounded by the sauce-flavored wine lees-based porous carbon as claimed in claim 1, wherein the mass ratio of the porous carbon precursor to the activating agent is 1.

4. The preparation method of the Maotai-flavor wine vinasse-based porous carbon composite ionic liquid gas adsorbent according to claim 1 or 3, wherein the activating agent comprises but is not limited to KOH and K ₂ CO ₃ 、KHCO ₃ 、K ₃ PO ₄ 、NaOH、H ₃ PO ₄ 、ZnCl ₂ And NaNH ₂ 。

5. The preparation method of the sauce-flavored wine lees-based porous carbon composite ionic liquid gas adsorbent according to claim 1, wherein the mass ratio of the sauce-flavored wine lees-based porous carbon to the ionic liquid is 1.

6. The preparation method of the ionic liquid gas adsorbent compounded from the Maotai-flavor wine lees-based porous carbon according to claim 1 or 5, wherein the ionic liquid is carboxylate proton type ionic liquid.

7. The preparation method of the Maotai-flavor wine lees-based porous carbon composite ionic liquid gas adsorbent according to claim 6, wherein the organic amine structure required by the synthesis of the carboxylate proton type ionic liquid comprises but is not limited to ethylenediamine, diethylenetriamine, tetraethylenepentamine, polyethyleneimine, N- [3- (trimethoxysilyl) propyl ] ethylenediamine, 3-aminopropyltrimethoxysilane, tris (2-dimethylaminoethyl) amine, triethanolamine, tris (3, 6-dioxaheptyl) amine.

8. The preparation method of the Maotai-flavor wine vinasse-based porous carbon composite ionic liquid gas adsorbent according to claim 6, wherein the polycarboxylic acid structure required by the synthesis of the carboxylate proton type ionic liquid comprises but is not limited to iminodiacetic acid, ethylenediamine-N, N' -diacetic acid, nitrilotriacetic acid, 1,2,3, 4-butanetetracarboxylic acid and benzimidazole-5-carboxylic acid.

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