CN115873136A - A kind of biomass pretreatment method, nanometer material - Google Patents

Abstract

The invention belongs to the technical field of environmental protection, and in particular relates to a biomass pretreatment method and nanometer materials. The biomass pretreatment method comprises: using choline chloride-ethylene glycol-p-toluenesulfonic acid ternary deep eutectic solvent to react with biomass; wherein, choline chloride-ethylene glycol-p-methyl In the benzenesulfonic acid ternary deep eutectic solvent, the molar ratio of choline chloride, ethylene glycol and p-toluenesulfonic acid is 1:2:(0.01‑1). The pretreatment method is based on choline chloride-ethylene glycol-p-toluenesulfonic acid ternary deep eutectic solvent, which has different solubility of reactants and products, and well avoids side reactions generated during the reaction; Moreover, the choline chloride-ethylene glycol-p-toluenesulfonic acid ternary deep eutectic solvent is easy to separate from the product, which is convenient for recycling. The recovery rate can reach 90%, and the purity can also reach 90%.

Description

A kind of biomass pretreatment method, nanometer material

technical field

The invention belongs to the technical field of environmental protection, and in particular relates to a biomass pretreatment method and nanometer materials.

Background technique

With the increasingly serious environmental pollution, people's awareness of environmental protection is getting stronger and stronger, and the fossil resources are constantly being exhausted. The development of new renewable energy has become a major issue with global strategic significance. Biomass is an important part of renewable energy, and it is also the most promising renewable energy for industrialization and scale. Biomass reserves are extremely rich. It is estimated that the energy stored by plants on the earth through photosynthesis is about 10 times that of the world's annual energy consumption. The development and utilization of biomass is the whole process of converting various biomass raw materials into high value-added biomass energy, biological materials, petroleum product substitutes and by-products through different channels. In today's increasingly prominent energy pressure, the development and utilization of biomass is of great significance.

Existing biomass pretreatment methods mainly use chemical and physical methods such as strong acid and strong alkali to destroy the structure of biomass so as to achieve the purpose of pretreatment. However, there are problems such as serious pollution in chemical and physical pretreatment methods such as strong acid and strong alkali.

Therefore, an environmentally friendly biomass treatment method is necessary.

Contents of the invention

In view of the above problems, one of the objects of the present invention is to provide a biomass pretreatment method, which uses a ternary deep eutectic solvent to cut off the inherent structure of the biomass to make it a nano-scale material. Moreover, the ternary deep eutectic solvent in the treatment method can be recovered, and the recovery rate can reach 90%, and the purity of the recovered ternary deep eutectic solvent can also reach 90%.

In order to achieve the above object, the present invention can adopt the following technical solutions:

One aspect of the present invention provides a biomass pretreatment method, which includes: using choline chloride-ethylene glycol-p-toluenesulfonic acid ternary deep eutectic solvent to react with biomass; wherein, choline chloride -In the ethylene glycol-p-toluenesulfonic acid ternary deep eutectic solvent, the molar ratio of choline chloride, ethylene glycol and p-toluenesulfonic acid is 1:2:(0.01-1).

Another aspect of the present invention provides a nanomaterial obtained after pretreatment by the above-mentioned biomass pretreatment method.

The beneficial effects of the present invention include: the biomass pretreatment method provided by the present invention is based on choline chloride-ethylene glycol-p-toluenesulfonic acid ternary deep eutectic solvent, which is very good for the solubility difference of reactants and products The side reaction generated in the reaction process has been avoided; and the choline chloride-ethylene glycol-p-toluenesulfonic acid ternary deep eutectic solvent is easily separated from the product, which is convenient for recycling, and the recovery rate can reach 90%, and the purity It can also reach 90%.

Description of drawings

Fig. 1 is the electron micrograph of the nano lignin fragment obtained in embodiment 2;

FIG. 2 is an electron micrograph of nanocellulose fibrils obtained in Example 2.

Detailed ways

The examples given are for better description of the present invention, but the content of the present invention is not limited to the examples given. Therefore, non-essential improvements and adjustments to the implementation by those skilled in the art based on the content of the invention above still fall within the protection scope of the present invention.

The terminology used herein is for describing particular embodiments only and is not intended to limit the present disclosure. Expressions in the singular include expressions in the plural unless there are clearly different meanings in the context. As used herein, it should be understood that terms such as "comprising", "having", "comprising" are intended to indicate the presence of features, numbers, operations, components, parts, elements, materials or combinations. The terms of the present invention are disclosed in the specification, and it is not intended to exclude the possibility that one or more other features, numbers, operations, components, parts, elements, materials or combinations thereof may exist or may be added. As used herein, "/" may be interpreted as "and" or "or" as the case may be.

An embodiment of the present invention provides a biomass pretreatment method, which includes: using choline chloride-ethylene glycol-p-toluenesulfonic acid ternary deep eutectic solvent to react with biomass; wherein, choline chloride -In the ethylene glycol-p-toluenesulfonic acid ternary deep eutectic solvent, the molar ratio of choline chloride, ethylene glycol and p-toluenesulfonic acid is 1:2:(0.01-1).

It should be noted that the deep eutectic solvent is a kind of two-component or three-component mixture that can be melted at low temperature by simply mixing a certain stoichiometric ratio of hydrogen bond acceptors and hydrogen bond donors under mild conditions. Has great adjustability. In addition, the choline chloride-ethylene glycol-p-toluenesulfonic acid ternary deep eutectic solvent has a wide range of raw materials, low price, low toxicity or non-toxicity.

It should also be noted that in the present invention, the deep eutectic solvent can effectively relieve the force between hydrogen bonds, cut off the inherent structure of biomass, and make it reach nano-scale materials, that is, biomass can be converted into nano-materials . In addition, in the deep eutectic solvent of the present invention, the hydrogen bond acceptor is choline chloride and the hydrogen bond donor is ethylene glycol and p-toluenesulfonic acid. In addition, the deep eutectic solvent in the present invention has different solubility of reactants and products, which well avoids side reactions generated during the reaction process, and improves yield and purity.

In some implementations, in the above biomass pretreatment method, the molar ratio of choline chloride, ethylene glycol and p-toluenesulfonic acid is 1:2:(0.06-0.6). It should be noted that, in the above-mentioned choline chloride-ethylene glycol-p-toluenesulfonic acid ternary deep eutectic solvent, different above-mentioned choline chloride-ethylene glycol-p-toluenesulfonic acid mol ratio The conversion ability of biomass is different, and the molar ratio of choline chloride, ethylene glycol and p-toluenesulfonic acid can be selected as 1:2: (0.01-1), and the recovery rate and purity of the ternary deep eutectic solvent can be Reach 85%. Wherein, when the molar ratio is 1:2:(0.06-0.6), the recovery rate and the purity of the ternary deep eutectic solvent can reach 90%, so the choline chloride, ethylene glycol and p-toluenesulfonic acid The molar ratio is preferably 1:2:(0.06-0.6), such as 1:2:0.1, 1:2:0.3 or 1:2:0.5, etc. In addition, when the molar ratio of choline chloride, ethylene glycol and p-toluenesulfonic acid is less than 1:2:1 or greater than 1:2:0.0, the ternary deep eutectic solvent cannot be generated.

In some specific implementations, in the above-mentioned biomass pretreatment method, the preparation method of choline chloride-ethylene glycol-p-toluenesulfonic acid ternary deep eutectic solvent comprises: choline chloride, ethylene glycol and p-toluenesulfonic acid After the toluenesulfonic acid is mixed, it is prepared by heating to 70°C-90°C in a microwave reactor.

It should be noted that the preparation conditions of the choline chloride-ethylene glycol-p-toluenesulfonic acid ternary deep eutectic solvent are mild and the process is simple. In addition, the preparation of choline chloride-ethylene glycol-p-toluenesulfonic acid ternary deep eutectic solvent can also use an oil bath for heating except that microwave reactor can be used for heating, but the oil bath heating time is longer The microwave reactor heating is long, and the rate of recovery of the ternary deep eutectic solvent is not as good as the microwave reactor heating, so preferably use microwave reactor heating in the present invention to prepare choline chloride-ethylene glycol-p-toluenesulfonic acid three Elemental deep eutectic solvent.

In some specific implementations, in the above-mentioned biomass pretreatment method, the reaction time for heating the microwave reactor to prepare the choline chloride-ethylene glycol-p-toluenesulfonic acid ternary deep eutectic solvent can be 10s-120s, Such as 20s, 50s or 100s etc. It should be noted that heating in a microwave reactor can greatly shorten the reaction time (the heating time in an oil bath is about 3 hours) compared with heating in an oil bath.

In some implementations, in the above biomass pretreatment method, the mass ratio of biomass to choline chloride-ethylene glycol-p-toluenesulfonic acid ternary deep eutectic solvent is 1:(1-20). It should be noted that the mass ratio of biomass and choline chloride-ethylene glycol-p-toluenesulfonic acid ternary deep eutectic solvent will also have an impact on the pretreatment effect, and 1 can be selected in the present invention: (1 -20), such as 1:5, 1:10 or 1:15, etc., preferably 1:10.

In some specific implementations, in the above biomass pretreatment method, the biomass is roses.

It should be noted that roses are usually discarded after being used for ornamental use, and these rose petals can be recycled for processing and fully utilized, thereby improving economic and social benefits and reducing waste.

In some implementations, in the above biomass pretreatment method, the biomass is ≤60 mesh rose flower powder. It should be noted that the rose powder of ≤60 mesh will react more fully with the choline chloride-ethylene glycol-p-toluenesulfonic acid ternary deep eutectic solvent.

In some implementations, in the above-mentioned biomass pretreatment method, the method of using choline chloride-ethylene glycol-p-toluenesulfonic acid ternary deep eutectic solvent to react with biomass comprises: choline chloride -After mixing ethylene glycol-p-toluenesulfonic acid ternary deep eutectic solvent with biomass; heating to 60°C-120°C for reaction; adding water after reaction, stirring, standing, and layering; supernatant recovery, The lower layer is washed with water, centrifuged, frozen, and dried to obtain nanomaterials.

It should be noted that the above-mentioned operations such as stirring, standing still, layering, washing, centrifuging, freezing or drying are all conventional operations in the art. In addition, the choline chloride-ethylene glycol-p-toluenesulfonic acid ternary deep eutectic solvent in the present invention can be stirred after adding water, standing, layering, reclaiming the supernatant, which is choline chloride -Ethylene glycol-p-toluenesulfonic acid ternary deep eutectic solvent; simple and convenient recycling.

In some implementations, in the above-mentioned biomass pretreatment method, stirring is carried out during the above heating to 60°C-120°C for reaction, and the stirring speed may be 400rpm-900rpm, such as 500rpm, 600rpm or 800rpm.

In some specific embodiments, in the above-mentioned biomass pretreatment method, the reaction time for the above-mentioned heating to 60°C-120°C for the reaction may be 5min-60min, such as 10min, 30min or 50min.

Another aspect of the present invention provides a nanomaterial obtained after pretreatment by the above-mentioned biomass pretreatment method. It should be noted that biomass can be converted into nanomaterials through the pretreatment method in the present invention, thereby expanding the utilization range of biomass and realizing the repeated utilization of renewable resources.

In order to better understand the present invention, the content of the present invention will be further clarified below in conjunction with specific examples, but the content of the present invention is not limited to the following examples.

1. Preparation of nanomaterials by reaction of rose powder and deep eutectic solvent

Example 1

Put choline chloride, ethylene glycol and p-toluenesulfonic acid into a flask at a molar ratio of 1:2:0.01 and put them into a microwave reactor, heat the temperature to 80°C and keep stirring for 30s to obtain a deep eutectic solvent ; Put 10g of deep eutectic solvent and 1g of rose powder (60 mesh) into a beaker and add the rotor, heat the water bath to 80°C, seal and keep stirring for 30min, and keep the rotating speed at 500rpm; after the reaction, add the obtained mixture to Ionized water was stirred and allowed to stand for stratification, and the upper liquid was taken out to recover the deep eutectic solvent and recycled. The recovery rate and purity of the deep eutectic solvent were 85% and 81% respectively. The remaining part was put into a centrifuge tube and added with deionized water to wash and separate, until the supernatant was neutral and the centrifugation was completed, and the obtained product was put into a lyophilizer for 24 hours to freeze-dry to obtain the final product.

Example 2

Put choline chloride, ethylene glycol and p-toluenesulfonic acid into a flask at a molar ratio of 1:2:0.06 and put them into a microwave reactor, heat the temperature to 80°C and keep stirring for 30s to obtain a deep eutectic solvent ; Put 10g of deep eutectic solvent and 1g of rose powder (60 mesh) into a beaker and add the rotor, heat the water bath to 80°C, seal and keep stirring for 30min, and keep the rotating speed at 500rpm; after the reaction, add the obtained mixture to Ionized water was stirred and allowed to stand for stratification, and the upper liquid was taken out to recover the deep eutectic solvent and recycled. The recovery rate and purity of the deep eutectic solvent were 94% and 91% respectively. The remaining part was put into a centrifuge tube and added with deionized water to wash and separate, until the supernatant was neutral and the centrifugation was completed, and the obtained product was put into a lyophilizer for 24 hours to freeze-dry to obtain the final product.

Example 3

Put choline chloride, ethylene glycol, and p-toluenesulfonic acid into a flask at a molar ratio of 1:2:0.6 and put them into a microwave reactor, heat the temperature to 80°C and keep stirring for 30 seconds to obtain a deep eutectic solvent . Put 10g of deep eutectic solvent and 1g of rose powder (60 mesh) into a beaker and add the rotor, heat the water bath to 80°C, seal and keep stirring for 30min, and keep the speed at 500rpm; after the reaction, add deionized water, stirred and allowed to stand for stratification, and the upper layer liquid was taken out to recover the deep eutectic solvent and recycled. The recovery rate and purity of the deep eutectic solvent were 95% and 93% respectively. The remaining part was put into a centrifuge tube and added with deionized water to wash and separate, until the supernatant was neutral and the centrifugation was completed, and the obtained product was put into a lyophilizer for 24 hours to freeze-dry to obtain the final product.

Example 4

Put choline chloride, ethylene glycol and p-toluenesulfonic acid into a flask in a molar ratio of 1:2:1 and put them into a microwave reactor, heat the temperature to 80°C and keep stirring for 30s to obtain a deep eutectic solvent ; Put 10g of deep eutectic solvent and 1g of rose powder (60 mesh) into a beaker and add the rotor, heat the water bath to 80°C, seal and keep stirring for 30min, and keep the rotating speed at 500rpm; after the reaction, add the obtained mixture to Ionized water was stirred and allowed to stand for stratification, and the upper liquid was taken out to recover the deep eutectic solvent and recycled. The recovery rate and purity of the deep eutectic solvent were 89% and 92% respectively. The remaining part was put into a centrifuge tube and added with deionized water to wash and separate, until the supernatant was neutral and the centrifugation was completed, and the obtained product was put into a lyophilizer for 24 hours to freeze-dry to obtain the final product.

Comparative example 1

Put choline chloride, ethylene glycol, and p-toluenesulfonic acid into a beaker at a molar ratio of 1:2:0.01 and put them in an oil bath, heat the temperature to 80°C and keep stirring for 3 hours to prepare a deep eutectic solvent ;Put 10g of deep eutectic solvent and 1g of rose powder (60 mesh) into the flask and add the rotor, heat the water bath to 80°C, seal and insulate and stir for 8 hours, and the rotation speed starts at 500rpm and later increases to 800rpm; after the reaction, the obtained Deionized water was added to the mixture, stirred and allowed to stand for stratification, and the upper liquid was taken out to recover the deep eutectic solvent and recycled. The recovery rate and purity of the deep eutectic solvent were 85% and 87%, respectively. The remaining part was put into a centrifuge tube and added with deionized water to wash and separate, until the supernatant was neutral and the centrifugation was completed, and the obtained product was put into a lyophilizer for 24 hours to freeze-dry to obtain the final product.

Comparative example 2

Put choline chloride, ethylene glycol and p-toluenesulfonic acid into a beaker at a molar ratio of 1:2:0.06 and put them in an oil bath, heat the temperature to 80°C and keep stirring for 3 hours to prepare a deep eutectic solvent ;Put 10g of deep eutectic solvent and 1g of rose powder (60 mesh) into the flask and add the rotor, heat the water bath to 80°C, seal and insulate and stir for 8 hours, and the rotation speed starts at 500rpm and later increases to 800rpm; after the reaction, the obtained Deionized water was added to the mixture, stirred and allowed to stand for stratification, and the upper liquid was taken out to recover the deep eutectic solvent and recycled. The recovery rate and purity of the deep eutectic solvent were 89% and 89% respectively. The remaining part was put into a centrifuge tube and added with deionized water to wash and separate, until the supernatant was neutral and the centrifugation was completed, and the obtained product was put into a lyophilizer for 24 hours to freeze-dry to obtain the final product.

2. Characterization of prepared nanomaterials and optimization of preparation parameters

The final product (nano-lignin fragments and nano-cellulose fibrils) prepared in Example 2 was observed with a transmission electron microscope, and the results are shown in Figure 1 and Figure 2 respectively. It can be seen that the final product has an obvious nanofibrous structure and is relatively dense And in good shape.

In addition, through Example 1 to Example 4, with the change of the molar ratio of the deep eutectic solvent components, the number of nanofibers of the final product prepared is increasing, indicating that the deep eutectic solvent in the present invention can be easily Good provides hydrogen bonds to cut off the inherent structure of biomass, making it reach nanoscale materials; however, with the change of molar ratio of deep eutectic solvent components, the yield and purity first increase and then decrease; deep eutectic solvent When the molar ratio of the components is 1:2:(0.06-0.6), the recovery rate and purity of the deep eutectic solvent can both reach 90%.

Furthermore, Comparative Example 1 and Comparative Example 2 are compared with Example 1 and Example 2, the microwave reactor used in Example 1 and Example 2 is heated, and the conventional oil bath used in Comparative Example 1 and Comparative Example 2 is heated. Heating, it can be known that using a microwave reactor for heating greatly shortens the reaction time, and the recovery and purity of the recovered deep eutectic solvent are also slightly higher than those for heating in an oil bath. Therefore, in the present invention, microwave reactors are preferred for heating to prepare deep eutectic solvents.

Finally, it is noted that the above embodiments are only used to illustrate the technical solutions of the present invention without limitation. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be carried out Modifications or equivalent replacements without departing from the spirit and scope of the technical solution of the present invention shall fall within the scope of the claims of the present invention.

Claims (10)

1. A method of biomass pretreatment, comprising: the method comprises the following steps of (1) reacting choline chloride-ethylene glycol-p-methylbenzenesulfonic acid ternary eutectic solvent with biomass; in the choline chloride-ethylene glycol-p-methylbenzenesulfonic acid ternary eutectic solvent, the molar ratio of choline chloride to ethylene glycol to p-methylbenzenesulfonic acid is 1: (0.01-1).

2. The biomass pretreatment method according to claim 1, wherein a molar ratio of choline chloride, ethylene glycol, and p-toluenesulfonic acid is 1: (0.06-0.6).

3. The biomass pretreatment method according to claim 1 or 2, wherein the choline chloride-ethylene glycol-p-methylbenzenesulfonic acid ternary eutectic solvent is prepared by a method comprising: the choline chloride, the ethylene glycol and the p-toluenesulfonic acid are mixed and heated to 70-90 ℃ by a microwave reactor to react to prepare the choline chloride-p-toluenesulfonic acid.

4. The biomass pretreatment method of claim 3, wherein the reaction time is 10s to 120s.

5. The biomass pretreatment method according to claim 1, 2 or 4, wherein the mass ratio of the biomass to the choline chloride-ethylene glycol-p-methylbenzenesulfonic acid ternary eutectic solvent is 1: (1-20).

6. The method of claim 1, 2 or 4, wherein the biomass is rose.

7. The biomass pretreatment method of claim 6, wherein the biomass is 60-mesh or smaller rose powder.

8. The biomass pretreatment method according to claim 1, 2, 4, or 7, wherein the method for reacting the biomass using the choline chloride-ethylene glycol-p-methylbenzenesulfonic acid ternary eutectic solvent comprises: mixing a choline chloride-ethylene glycol-p-methylbenzenesulfonic acid ternary eutectic solvent with biomass; heating to 60-120 ℃ for reaction; adding water after reaction, stirring, standing and layering; recovering supernatant, washing the lower layer with water, centrifuging, freezing, and drying to obtain nanometer material.

9. The biomass pretreatment method according to claim 8, wherein the stirring is performed while heating to 60 ℃ to 120 ℃ for reaction, and the rotation speed of the stirring is 400rpm to 900rpm.

10. A nanomaterial obtained after pretreatment by a biomass pretreatment method according to any one of claims 1 to 9.

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