Method for efficiently separating biomass components and application in preparation of feed additive

Abstract

The application discloses a biomass component efficient separation method and application in preparation of feed additives, and belongs to the technical field of lignocellulosic biomass pretreatment separation and animal feed production. The separation method adopts a composite clay-based catalyst and a proton acid coupling system to pretreat lignocellulosic biomass; the obtained suspension is treated, filtrate and filter residue are collected, the filtrate is purified to obtain a liquid component rich in lignin small molecules, oligosaccharides and polyols, and the filter residue is dried to obtain a high-purity cellulose component. The Mo / SiO2-Al2O3-Ce2O3 composite clay-based catalyst is coupled with a proton acid system, under relatively mild conditions, efficient fractionation conversion of lignocellulosic biomass components is realized, the liquid phase component can be further applied to preparation of feed additives, and the process is simple and economical.

Description

Technical Field

[0001] This invention belongs to the field of lignocellulose biomass pretreatment separation and animal feed production technology, specifically involving green biomass component separation methods, development of efficient catalytic systems and high-value application of subsequent products. Background Technology

[0002] Oligosaccharides and lignin components in lignocellulosic biomass are considered natural "prebiotics" and show great potential as functional feed additives due to their unique physicochemical properties. However, lignin's complex structure and large molecular weight make it difficult to ferment and digest directly in the intestines. Furthermore, the dense three-dimensional structure of biomass components often requires a series of demanding and lengthy pretreatment techniques to separate lignin and oligosaccharide components from the biomass.

[0003] Existing separation technologies focus on the utilization of (hemi)cellulose, leading to irreversible condensation and destruction of the lignin structure during the separation process. The utilization of lignin components often requires further purification and upgrading. One-pot catalytic reduction fractionation of lignin cellulose components has attracted widespread attention due to its high efficiency and economy. Designing an efficient catalytic fractionation system to promote the breaking of chemical bonds in the lignin cellulose structure, achieving the stripping of components while inhibiting the condensation of reaction intermediates, and thus directly obtaining low-molecular-weight lignin rich in phenolic monomers and oligosaccharide components, is of great significance for the economical application of biomass components in feed additives.

[0004] Clay-based catalysts are widely used in energy catalysis, coating materials, and other fields due to their excellent thermal stability, abundant surface acid sites, large reserves, and high economic efficiency. However, due to issues such as the single active site and surface metal leaching, key problems commonly arise in the catalytic fractionation of lignocellulose components, including poor selectivity, severe component polymerization, and rapid catalyst deactivation. Modifying and upgrading clay-based supports and loading highly active metals are expected to increase the upper limit of the inherent active sites of clay-based catalysts and improve catalyst deactivation, which is of great significance for achieving efficient and economical catalytic fractionation of lignocellulose components. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, the present invention aims to provide a method for the efficient separation of biomass components. The catalytic fractionation system coupled with a composite clay-based catalyst and phosphotungstic acid can achieve efficient separation of various components in lignocellulosic biomass, obtaining oligosaccharides and low molecular weight lignin components rich in phenolic monomers in a one-step process.

[0006] Another technical problem to be solved by the present invention is to provide the application of the above separation method in the preparation of feed additives. The oligosaccharide and lignin components obtained by separation show good economic efficiency and functionality in the field of feed additive application.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] A highly efficient method for separating biomass components involves pretreating lignocellulosic biomass using a composite clay-based catalyst coupled with a protic acid system. The resulting suspension is then processed, and the filtrate and filter residue are collected. The filtrate is purified to obtain polyols, oligosaccharides, and lignin components, while the filter residue is dried to obtain high-purity cellulose components.

[0009] The efficient separation method for biomass components uses phosphotungstic acid hydrate as the protonic acid. The composite clay-based catalyst uses SiO2-Al2O3-Ce2O3 as a support and molybdenum (Mo) as the active metal. Mo metal provides highly active metal hydrogenation sites, while the presence of the composite clay-based support Al2O3 ensures abundant acid sites for the catalyst. Ce2O3 provides a high oxygen vacancy concentration, and SiO2 has a suitable pore structure and high stability. Preferably, the amount of Mo metal added is 20% of the support mass.

[0010] The method for efficient separation of biomass components involves adding a composite clay-based catalyst at 15%-25% of the mass of lignocellulose biomass and adding a protonic acid at 45%-55% of the mass of lignocellulose biomass; preferably, the composite clay-based catalyst is added at 20% of the mass of lignocellulose biomass and the protonic acid is added at 50% of the mass of lignocellulose biomass.

[0011] The pretreatment reaction conditions for the efficient separation method of biomass components are: temperature 180-240℃, H2 atmosphere, initial pressure 1MPa, stirring rate 450-550rpm, and time 1-4h.

[0012] The efficient separation method for biomass components involves filtering the reaction suspension to obtain a solid residue rich in cellulose, washing it thoroughly with ethanol and water 3-5 times to obtain a liquid component rich in lignin macromolecules, oligosaccharides, and polyols, then evaporating the ethanol in the filtrate, and extracting it with dichloromethane 3-5 times to obtain an organic phase and an aqueous phase.

[0013] The method for efficient separation of biomass components includes the preparation of the composite clay carrier SiO2-Al2O3-Ce2O3:

[0014] (1) Dissolve the poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer (P123) in a mixed solution of hydrochloric acid and ethanol, add aluminum precursor salt and cerium precursor salt to obtain emulsion I;

[0015] (2) Add citric acid and stir overnight to obtain a gel-like liquid, then add zeolite;

[0016] (3) The composite clay carrier was obtained by hydrothermal aging overnight and then left to stand, dried and calcined.

[0017] The efficient separation method for biomass components uses cerium nitrate hexahydrate and aluminum nitrate nonahydrate as precursor salts. The hydrothermal aging conditions are stirring at 60°C for 12 hours, the drying conditions are maintaining at 105°C for 12 hours, and the calcination conditions are heating to 500°C at a heating rate of 3°C / min and maintaining at 500°C for 4 hours in an air atmosphere.

[0018] The efficient separation method for biomass components employs an impregnation method to load Mo metal. The specific steps are as follows: a composite clay carrier is added to an aqueous solution of ammonium molybdate tetrahydrate, then stirred evenly, and after hydrothermal aging, static drying, grinding and sieving, it is calcined to obtain a solid catalyst. The hydrothermal conditions are stirring at 60°C for 12 hours, the drying conditions are maintaining at 105°C for 12 hours, and the calcination conditions are heating to 500°C at a heating rate of 3°C / min in air and maintaining for 4 hours.

[0019] The above method is applied in the preparation of feed additives.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] (1) This invention uses a composite clay-based catalyst, which has abundant active sites and high stability. The SiO2 support possesses excellent pore structure and stability, the introduction of Al2O3 provides abundant acidic sites, and cerium oxide, as an oxygen-rich vacancy component, is introduced. The composite clay support provides excellent active sites through interaction with the active metal molybdenum. The catalytic fractionation system coupled with phosphotungstic acid can achieve efficient stripping of (semi)cellulose and lignin components from lignocellulosic biomass. Simultaneously, the obtained lignin macromolecules are saturated under hydrogenation, inhibiting the condensation of lignin intermediates. Characterization analysis of the liquid phase components by gas chromatography-mass spectrometry (GC-MS) and gel permeation chromatography (GPC) demonstrates that low molecular weight lignin and oligosaccharide liquid phase components rich in phenolic monomers can be efficiently separated in one step within the temperature range of 180℃-240℃. Specifically, under optimal conditions at 240℃, the yield of the cellulose-rich solid residue is 31.19%, and the yield of the organic phase component is as high as 60.79%.

[0022] (2) The separated liquid components also exhibit significant antibacterial properties and non-toxicity when used as feed additives. The overall process is simple and economical. Oligosaccharides at concentrations of 0.05% and above and lignin at concentrations of 0.01% and above can significantly inhibit the activity of luminescent bacteria and suppress intestinal flora imbalance. The addition of oligosaccharides and lignin in the range of 0.02%-0.2% has no significant inhibitory effect on the food intake and body weight of rats, and even has a slight effect on increasing the food intake and body weight of rats, with little effect on rat organs. Attached Figure Description

[0023] Figure 1 XRD patterns of the composite clay support and the catalyst after loading.

[0024] Figure 2 The images show the FTIR spectra of the composite clay support and the catalyst after loading.

[0025] Figure 3 GC-MS images of liquid phase components under different temperature treatments;

[0026] Figure 4 XRD patterns of solid components under different temperature treatments;

[0027] Figure 5 FTIR spectra of solid components treated at different temperatures;

[0028] Figure 6 GPC plots of liquid components under different temperature treatments;

[0029] Figure 7 Figure showing the effect of different concentrations of oligosaccharide and lignin additives on the food intake of rats;

[0030] Figure 8 Figure showing the effect of different concentrations of oligosaccharide and lignin addition on rat body weight;

[0031] Figure 9 Figure showing the effect of different concentrations of oligosaccharides and lignin on the organ coefficient of rats. Detailed Implementation

[0032] The present invention will be further described below with reference to specific embodiments.

[0033] The formulas for calculating the yield of fiber residue and the yield of organic phase components in this invention are as follows (1) and (2).

[0034] Fiber residue yield (%) = (Oven-dry mass of remaining residue after pretreatment / Oven-dry mass of raw material) × 100% (1)

[0035] Organic phase component yield (%) = (mass of pretreated organic phase / oven-dry mass of raw material) × 100% (2)

[0036] To investigate the toxicity risks of oligosaccharides and lignin when used as feed additives, one-way ANOVA was performed using SPSS 19.0 software. Data were analyzed using the least significant difference test (LSD) to compare and evaluate the statistical differences between the exposed group and the control group. Results are expressed as mean ± standard deviation (SD).

[0037] Example 1

[0038] Dissolve 2g of P123 in a mixture of 32mL of 37wt% hydrochloric acid and 40mL of ethanol, then add 4.2549g of aluminum nitrate nonahydrate and 1.6287g of cerium nitrate hexahydrate to obtain emulsion I.

[0039] After adding 1g of citric acid and stirring overnight to obtain a gel-like liquid, 2g of zeolite was added, and the mixture was hydrothermally aged at 60℃ overnight. After standing, it was dried at 105℃ and calcined at 500℃ for 4 hours with a temperature increase of 3℃ / min to obtain a composite clay carrier.

[0040] 2g of composite clay support was added to 30mL of aqueous solution containing 0.736g of ammonium molybdate tetrahydrate, stirred evenly, aged overnight at 60℃, dried at 105℃, ground and sieved, and then calcined at 500℃ for 4 hours at a heating rate of 3℃ / min to obtain a 20% Mo / SiO2-Al2O3-Ce2O3 catalyst.

[0041] The structural characteristics of the composite clay-based catalyst prepared in Example 1 were studied through various characterization methods, and the results are as follows:

[0042] like Figure 1 As shown, the crystal phase composition of the catalyst surface was analyzed by XRD. The diffraction peaks marked in the figure correspond to the characteristic diffraction peaks of SiO2, Al2O3 and Ce2O3, respectively, proving the successful preparation of the composite clay material.

[0043] Some of the diffraction peaks could not be determined because, during the in-situ synthesis of composite clay materials, the metals Al, Si, and Ce interacted to form new crystal phases.

[0044] For the 20% Mo / SiO2-Al2O3-Ce2O3 catalyst, the diffraction peak intensity of the support was found to be significantly reduced. This was attributed to the covering effect of the active metal after loading, which further illustrates the successful introduction of metal Mo, which is anchored on the surface of the composite clay support and acts as a highly active site to promote the breaking of chemical bonds in the lignocellulose.

[0045] like Figure 2 As shown, FTIR spectroscopy analysis of the catalyst surface revealed stretching vibration bands of Si-O and Si-O-Ce / Al bonds, confirming the successful synthesis of the clay composite material. Furthermore, interactions between the three metals were observed, with Ce and Al metals incorporated into the SiO2 lattice framework. Additionally, with the addition of Mo, new absorption bands were attributed to the stretching vibrations of Mo-O-Mo bonds in the active Mo metal oxide. This further indicates the abundance of oxygen species on the catalyst surface, resulting in good adsorption and selectivity for the reactants.

[0046] Example 2

[0047] 1.0031g of crushed poplar wood raw material, 0.2012g of the catalyst prepared in Example 1, and 0.5012g of phosphotungstic acid hydrate were placed in a 50mL high-pressure reactor, with 30mL of anhydrous ethanol as the reaction solvent.

[0048] After purging the air from the reactor with H2, maintain the initial pressure at 1 MPa and the rotation speed at 500 rpm, and react at 180℃ for 4 hours.

[0049] After the reaction is complete, the autoclave is quickly placed in an ice-water bath to cool down rapidly. Once the temperature drops to room temperature, the autoclave is opened and the reaction product is removed.

[0050] First, the solid and liquid phases are separated by filtration using a sand core funnel. The liquid component is obtained by thorough washing with ethanol and water 3-5 times, while the solid residue is dried at 105°C to obtain the oven-dry weight of the fiber residue. Then, the ethanol in the filtrate is evaporated to dryness, and dichloromethane is added for extraction 3-5 times to obtain the organic phase and the aqueous phase. The organic phase is rich in lignin, oligosaccharides, and polyols. After evaporation to dryness, the mass of the organic phase is recorded, while phosphotungstic acid hydrate exists in the aqueous phase and is further separated and recovered.

[0051] The molecular weight of the liquid phase components was determined by GPC, and the results are as follows: Figure 6 As shown, the number-average molecular weight (Mn) is 358 and the weight-average molecular weight (Mw) is 671.

[0052] Calculations show that the fiber residue yield was 59.21%, the organic phase yield was 35.91%, and the phenolic monomer content was 40.63%.

[0053] Example 3

[0054] 1.0057g of crushed poplar wood raw material, 0.2022g of the catalyst prepared in Example 1, and 0.5015g of phosphotungstic acid hydrate were placed in a 50mL high-pressure reactor, with 30mL of anhydrous ethanol as the reaction solvent.

[0055] After purging the air from the reactor with H2, maintain the initial pressure at 1 MPa and the rotation speed at 500 rpm, and react at 240℃ for 4 hours.

[0056] After the reaction is complete, the autoclave is quickly placed in an ice-water bath to cool down rapidly. Once the temperature drops to room temperature, the autoclave is opened and the reaction product is removed.

[0057] First, the solid and liquid phases are separated by filtration using a sand core funnel. The liquid component is obtained by thorough washing with ethanol and water 3-5 times, while the solid residue is dried at 105°C to obtain the oven-dry weight of the fiber residue. Then, the ethanol in the filtrate is evaporated to dryness, and dichloromethane is added for extraction 3-5 times to obtain the organic phase and the aqueous phase. The organic phase is rich in lignin, oligosaccharides, and polyols. After evaporation to dryness, the mass of the organic phase is recorded, while phosphotungstic acid hydrate exists in the aqueous phase and is further separated and recovered.

[0058] The molecular weight of the liquid phase components was determined by GPC, and the results are as follows: Figure 6 As shown, the number-average molecular weight (Mn) is 331 and the weight-average molecular weight (Mw) is 581.

[0059] Calculations show that the fiber residue yield was 31.19%, the organic phase yield was 60.79%, and the phenolic monomer content was 45.67%.

[0060] XRD and FTIR analyses were performed on the raw poplar wood and the solid residues obtained in Examples 2 and 3. The XRD results are as follows: Figure 4 As shown, all samples maintained good crystallinity compared to the raw poplar wood, demonstrating that the cellulose components were well preserved. This was confirmed by FTIR results (…). Figure 5 It can be seen that at 1025cm -1 The left and right absorption peaks correspond to the COC and C-OH stretching vibrations of the β-glycosidic bonds between sugar units in cellulose. The solids obtained in Examples 2 and 3 exhibited obvious cellulose structural properties, proving that the cellulose structure was effectively preserved after treatment. Studies indicate that at 1711 cm⁻¹... -1 The absorption peaks at 1600 and 1514 cm⁻¹ correspond to the C=O bond vibrations in the lignin structure. -1 The absorption peak at this point is related to the vibration of the lignin aromatic ring skeleton, while compared with the raw materials, the absorption peak at 1500-1750 cm⁻¹ in Examples 2 and 3 is significantly higher. -1 The absorption peaks within the range were significantly reduced, proving that the lignin structure was effectively removed.

[0061] Example 4

[0062] 1.0062g of crushed poplar wood raw material, 0.2028g of the catalyst prepared in Example 1, and 0.5001g of phosphotungstic acid hydrate were placed in a 50mL high-pressure reactor, with 30mL of anhydrous ethanol as the reaction solvent.

[0063] After purging the air from the reactor with H2, maintain the initial pressure at 1 MPa and the rotation speed at 500 rpm, and react at 220℃ for 4 hours.

[0064] After the reaction is complete, the autoclave is quickly placed in an ice-water bath to cool down rapidly. Once the temperature drops to room temperature, the autoclave is opened and the reaction product is removed.

[0065] First, the solid and liquid phases are separated by filtration using a sand core funnel. The liquid component is obtained by thorough washing with ethanol and water 3-5 times, while the solid residue is dried at 105°C to obtain the oven-dry weight of the fiber residue. Then, the ethanol in the filtrate is evaporated to dryness, and dichloromethane is added for extraction 3-5 times to obtain the organic phase and the aqueous phase. The organic phase is rich in lignin, oligosaccharides, and polyols. After evaporation to dryness, the mass of the organic phase is recorded, while phosphotungstic acid hydrate exists in the aqueous phase and is further separated and recovered.

[0066] Calculations showed that the fiber residue yield was 42.20% and the organic phase yield was 54.17%.

[0067] Example 5

[0068] 1.0009g of crushed poplar wood raw material, 0.2048g of the catalyst prepared in Example 1, and 0.5021g of phosphotungstic acid hydrate were placed in a 50mL high-pressure reactor, with 30mL of anhydrous ethanol as the reaction solvent.

[0069] After purging the air from the reactor with H2, maintain the initial pressure at 1 MPa and the rotation speed at 500 rpm, and react at 220°C for 2 hours.

[0070] After the reaction is complete, the autoclave is quickly placed in an ice-water bath to cool down rapidly. Once the temperature drops to room temperature, the autoclave is opened and the reaction product is removed.

[0071] First, the solid and liquid phases are separated by filtration using a sand core funnel. The liquid component is obtained by thorough washing with ethanol and water 3-5 times, while the solid residue is dried at 105°C to obtain the oven-dry weight of the fiber residue. Then, the ethanol in the filtrate is evaporated to dryness, and dichloromethane is added for extraction 3-5 times to obtain the organic phase and the aqueous phase. The organic phase is rich in lignin, oligosaccharides, and polyols. After evaporation to dryness, the mass of the organic phase is recorded, while phosphotungstic acid hydrate exists in the aqueous phase and is further separated and recovered.

[0072] Calculations show that the fiber residue yield was 67.11%, and the organic phase yield was 24.12%.

[0073] Example 6

[0074] Using the liquid phase component prepared in Example 3 as raw material, and bright luminescent bacteria as test organisms, the 24h inhibition rate of the luminescent bacteria was determined in accordance with GB / T15441-1995 within the concentration range of 0.01%-1% oligosaccharide and lignin.

[0075] When the oligosaccharide concentration gradients were 0.01%, 0.05%, 0.1%, 0.5%, and 1%, the inhibition rates against luminescent bacteria were 3%, 78%, 92%, 100%, and 100%, respectively.

[0076] Because lignin produces a deep color that interferes with the experiment when prepared into a solution, the maximum concentration was set at 0.1%. At lignin concentrations of 0.01%, 0.05%, and 0.1%, the inhibition rates against luminescent bacteria were 76%, 96%, and 99%, respectively.

[0077] Example 7

[0078] Using the liquid phase component prepared in Example 3 as raw material, clean-grade rats were used as test organisms. In accordance with GB14924.3 and GB / T 23179-2008, after acclimatizing in the laboratory for 1 week, rats of uniform size with a weight difference not exceeding 20% ​​of the average weight were selected for exposure to oligosaccharides and lignin. The concentrations of the two target substances were set at 0.02% (mass fraction) and 0.2% (mass fraction) of the feed, respectively. The drugs were administered by gavage. The total exposure time was 28 days. Rats were generally observed every 3 days, and their feed intake rate and weight were recorded. After 28 days of exposure, the rats were dissected, and the organ coefficients of the heart, liver, spleen, lungs, and kidneys were measured.

[0079] The addition of oligosaccharides and lignin in the range of 0.02%-0.2% did not significantly inhibit food intake and body weight in rats, and even slightly increased them. The effects on rat organs were minimal; only the organ coefficient of the spleen was increased in the high-concentration (0.2%) oligosaccharide exposure group. Low-concentration (0.02%) oligosaccharides and low- and high-concentration (0.02%) lignin had no significant effect on the rat spleen. Detailed data are compiled in [link to relevant documentation]. Figure 7 , Figure 8 , Figure 9 middle.

Claims

1. A method for efficient separation of biomass components, characterized in that, A composite clay-based catalyst coupled with a protic acid system was used to pretreat lignocellulosic biomass. The obtained suspension was processed, and the filtrate and filter residue were collected. The filtrate was purified to obtain polyols, oligosaccharides and lignin components, and the filter residue was dried to obtain cellulose components. The protic acid was phosphotungstic acid hydrate. The composite clay-based catalyst used SiO2-Al2O3-Ce2O3 as a support and molybdenum as the active metal. The amount of the composite clay-based catalyst added is 15%-25% of the mass of lignocellulose biomass, and the amount of protonic acid added is 45%-55% of the mass of lignocellulose biomass; the pretreatment reaction process conditions are: temperature 180-240℃, H2 atmosphere, initial pressure 1MPa, stirring speed 450-550rpm, and time 1-4h. The preparation steps of the SiO2-Al2O3-Ce2O3 support are as follows: (1) Dissolve the poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer in a mixed solution of hydrochloric acid and ethanol, add aluminum precursor salt and cerium precursor salt to obtain emulsion I; (2) Add citric acid and stir overnight to obtain a gel-like liquid, then add zeolite; (3) The composite clay carrier was obtained by hydrothermal aging overnight and then drying and calcining. The hydrothermal aging conditions were 60℃ and stirring for 12 hours.

2. The efficient separation method for biomass components according to claim 1, characterized in that, After the reaction, the suspension was filtered to obtain a solid residue rich in cellulose. The residue was washed thoroughly with ethanol and water 3-5 times to obtain a liquid component rich in lignin macromolecules, oligosaccharides and polyols. The ethanol in the filtrate was then evaporated, and dichloromethane was added for extraction 3-5 times to obtain the organic phase and the aqueous phase.

3. The efficient separation method for biomass components according to claim 1, characterized in that, The cerium precursor salt is cerium nitrate hexahydrate, and the aluminum precursor salt is aluminum nitrate nonahydrate; in step (3), the drying condition is to keep it at 105°C for 12 hours, and the calcination condition is to raise the temperature to 500°C at a heating rate of 3°C / min and keep it at 500°C for 4 hours in an air atmosphere.

4. The efficient separation method for biomass components according to claim 1, characterized in that, The active metal was loaded using an impregnation method. The specific steps were as follows: the composite clay carrier was added to an aqueous solution of ammonium molybdate tetrahydrate, and then stirred evenly. After hydrothermal aging, static drying, grinding and sieving, the solid catalyst was obtained by calcination. The hydrothermal conditions were stirring at 60℃ for 12 hours, the drying conditions were maintaining at 105℃ for 12 hours, and the calcination conditions were raising the temperature to 500℃ at a heating rate of 3℃ / min in air and maintaining it for 4 hours.

Images