CN116606450A - A method and application of iron ion catalysis to promote the humification of biomass to synthesize artificial humus - Google Patents

Abstract

The invention discloses a method and application of iron ion catalyzing and promoting the humification of biomass to synthesize artificial humus, which relates to a method and application of humification reaction of biomass. The purpose of the invention is to solve the problem of low yield of artificial humic acid prepared by hydrothermal humification. Method: 1. Crushing the biomass, transferring the pulverized biomass to the reactor, then adding alkali, iron ion catalyst and water into the reactor, stirring evenly, and carrying out the closed hydrothermal reaction; 2. The hydrothermal reaction The final product is subjected to solid-liquid separation, and then the solid product and the liquid product are respectively subjected to humus recovery. Solid humic acid is used for the removal of lead ions in lead-containing wastewater. In the biomass hydrothermal process, the present invention uses iron ions as a catalyst to accelerate the hydrolysis of biomass macromolecules, promote the transformation of humus, greatly shorten the reaction time, and increase the yield of artificial humic acid by up to 107.98%. The overall production efficiency is increased by more than 8 times.

Description

A kind of iron ion catalysis promotes the method for the humification of biomass to synthesize artificial humus and application

technical field

The invention relates to a method and application of biomass humification reaction.

Background technique

Biomass includes straw, wood and other lignocellulose (lignin for short) produced in the process of agricultural and forestry production, leftovers of agricultural product processing, agricultural and forestry waste, and livestock manure and waste in the process of animal husbandry. Among them, straw is a typical representative of waste biomass. my country has huge straw resources. At present, my country's straw resources are mainly used as fertilizers, supplemented by feed and fuel utilization. Humus is an important part of soil organic matter and the key to soil fertility. However, under natural conditions, the formation of humus is slow and complex. Therefore, the efficient degradation and resource utilization of straw waste biomass is an urgent problem to be solved.

The hydrothermal method can simulate the natural humification process, overcome the time barrier in the long-term process of diagenesis in the natural environment, and accelerate the progress of biomass humification. The conversion of straw into humus-like substance and application through hydrothermal humification is conducive to the high-value utilization of potential resources while improving the soil. However, in the method of hydrothermal humification, the yield of humus is not high, and the humification rate (humic acid/fulvic acid) is low. Therefore, it is necessary to strengthen the humification transformation of straw biomass in the hydrothermal process.

Contents of the invention

The purpose of the present invention is to solve the problem of low yield of artificial humic acid prepared by hydrothermal humification, and provide a method and application of iron ion catalyzed promotion of biomass humification to synthesize artificial humus.

A method for iron ion catalysis to promote the humification of biomass to synthesize artificial humus, comprising the steps of:

1. Crushing the biomass, transferring the pulverized biomass to the reactor, then adding alkali, iron ion catalyst and water into the reactor, stirring evenly, and performing a closed hydrothermal reaction;

2. The product after the hydrothermal reaction is subjected to solid-liquid separation, and then the humus is recovered from the solid product and the liquid product respectively.

The solid-liquid separation is separated by centrifugation or filtration, and the obtained liquid product is directly used as a liquid fertilizer or humic acid is extracted through acid analysis to obtain solid humic acid; the obtained solid product is washed to neutral, Dried to obtain a humus product for use as soil improvement application.

Solid humic acid is used for the removal of lead ions in lead-containing wastewater.

Beneficial effects of the present invention:

1. The biomass used in the present invention has a wide range of sources, is cheap and easy to obtain, has low operating costs, and is easy to popularize and apply;

2. In the biomass hydrothermal process, the present invention uses iron ions as a catalyst to accelerate the hydrolysis of biomass macromolecules, promote the transformation of humus, greatly shorten the reaction time, and increase the yield of artificial humic acid by up to 107.98% %, the overall production efficiency is increased by more than 8 times;

3. The present invention has the advantages of simple operation, short time consumption, high humification rate, clean and environment-friendly production process, and the like.

Description of drawings

Fig. 1 is the picture that is artificial humic acid surface functional group, among the figure 1 is the artificial humic acid Fe-AHA _6h that embodiment 1 prepares, and 2 is the artificial humic acid A-HA _24h that comparative example 1 prepares;

Fig. 2 is the solid-state ¹³ C nuclear magnetic resonance spectrogram of the artificial humic acid prepared by embodiment 1 and comparative example 1, among the figure 1 is the artificial humic acid Fe-AHA _6h prepared by embodiment 1, and 2 is prepared by comparative example 1 Artificial humic acid A-HA _24h ;

Fig. 3 is the three-dimensional fluorescence spectrogram of the liquid artificial humic acid prepared by comparative example 1;

Fig. 4 is the three-dimensional fluorescence spectrogram of the liquid artificial humic acid prepared in embodiment 1;

Fig. 5 is the precursor small molecule glucose concentration of the artificial humic acid in the hydrothermal humification process of embodiment 2 and comparative example 2 changes figure with reaction time, among the figure 1 is the artificial humic acid Fe- prepared by embodiment 1 AHA _6h , 2 is the artificial humic acid A-HA _24h that comparative example 1 prepares;

Fig. 6 is the variation diagram of the concentration of the precursor small molecule 5-hydroxymethylfurfural of artificial humic acid in the hydrothermal humification process of embodiment 2 and comparative example 2 with the reaction time, and among the figure 1 is the artificial humic acid prepared by embodiment 1. Humic acid Fe-AHA _6h , 2 is the artificial humic acid A-HA _24h that comparative example 1 prepares;

Fig. 7 is the adsorption figure of artificial humic acid to lead in application example 1, among the figure 1 is the artificial humic acid Fe-AHA _6h that embodiment 1 prepares, and 2 is the artificial humic acid A-HA _24h that comparative example 1 prepares .

Detailed ways

Specific embodiment one: the present embodiment a kind of iron ion catalyzes and promotes the method for the humification of biomass to synthesize artificial humus, comprising the following steps:

1. Crushing the biomass, transferring the pulverized biomass to the reactor, then adding alkali, iron ion catalyst and water into the reactor, stirring evenly, and performing a closed hydrothermal reaction;

2. The product after the hydrothermal reaction is subjected to solid-liquid separation, and then the humus is recovered from the solid product and the liquid product respectively.

Specific embodiment 2: The difference between this embodiment and specific embodiment 1 is that the biomass described in step 1 is straw, trees, leftovers of agricultural product processing industry, agricultural and forestry waste, and animal husbandry production produced in the process of agricultural and forestry production. One or more mixtures of poultry manure and waste in the process. Other steps are the same as in the first embodiment.

Embodiment 3: The difference between this embodiment and Embodiment 1 or 2 is that in Step 1, a crusher is used to crush the biomass into fine pieces with a diameter of 0.1-2 cm. Other steps are the same as those in Embodiment 1 or 2.

Embodiment 4: This embodiment differs from Embodiment 1 to Embodiment 3 in that the alkali described in step 1 is one or more of sodium hydroxide and potassium hydroxide. Other steps are the same as those in Embodiments 1 to 3.

Embodiment 5: The difference between this embodiment and Embodiment 1 to Embodiment 4 is that the mass ratio of the alkali in step 1 to the pulverized biomass is 1: (1-10). Other steps are the same as those in Embodiments 1 to 4.

Specific embodiment six: the difference between this embodiment and specific embodiments one to five is: the iron ion catalyst described in step one is one or more mixtures in ferric chloride, ferric sulfate and ferric nitrate; The mass ratio of the iron ion catalyst described in step one to the pulverized biomass is 1:(5-20). Other steps are the same as those in Embodiments 1 to 5.

Embodiment 7: The difference between this embodiment and Embodiment 1 to Embodiment 6 is that the mass ratio of water and pulverized biomass in step 1 is 1g:(6mL-15mL). Other steps are the same as those in Embodiments 1 to 6.

Embodiment 8: This embodiment differs from Embodiments 1 to 7 in that: the temperature of the hydrothermal reaction in step 1 is 180°C-220°C, and the time of the hydrothermal reaction is 2h-20h. Other steps are the same as those in Embodiments 1 to 7.

Specific embodiment nine: the difference between this embodiment and specific embodiments one to eight is: the solid-liquid separation described in step 2 is separated by centrifugation or filtration, and the obtained liquid product is directly used as liquid fertilizer or passed through acid The humic acid is extracted by analysis to obtain solid humic acid; the obtained solid product is washed to neutrality and dried to obtain a humic substance product, which can be used as a soil improvement application. Other steps are the same as those in Embodiments 1 to 8.

Embodiment 10: In this embodiment, the solid humic acid is used for the removal of lead ions in lead-containing wastewater.

Adopt the following examples to verify the beneficial effects of the present invention:

Embodiment 1: a kind of method for ferric ion catalyzed biomass humification reaction is to be completed according to the following steps:

1. Use a crusher to crush the corn stalks, transfer 10g of pulverized biomass to a 200mL reactor, then add 2.0g of potassium hydroxide (analytical pure), 0.820g of ferric chloride (analytical pure), 100mL deionized water, stir evenly, carry out airtight hydrothermal reaction, the temperature of hydrothermal reaction is 200℃, and the time of hydrothermal reaction is 6h;

2. After the reaction is finished, cool down to room temperature, open the reaction kettle, separate the product after the hydrothermal reaction from solid to liquid, filter the liquid product through 0.22 μm, and then adjust the pH value of the liquid to 1- 2. Precipitate solid, centrifuge solid-liquid separation, finally collect solid, wash and dry to obtain artificial humic acid (Fe-AHA _6h ).

Comparative example 1: a kind of method of biomass humification reaction is finished according to the following steps:

1. Use a crusher to crush corn stalks, transfer 10g of crushed biomass to a 200mL reactor, then add 2.0g of potassium hydroxide (analytical grade) and 100mL of deionized water into the reactor, stir evenly, and seal Hydrothermal reaction, the temperature of hydrothermal reaction is 200℃, and the time of hydrothermal reaction is 24h;

2. After the reaction is finished, cool down to room temperature, open the reaction kettle, separate the product after the hydrothermal reaction from solid to liquid, filter the liquid product through 0.22 μm, and then adjust the pH value of the liquid to 1- 2. Precipitate solids, centrifuge solid-liquid separation, finally collect solids, wash and dry to obtain artificial humic acid to obtain artificial humic acid (A-HA _24h ).

Table 1 is the effect of adding FeCl in the embodiment ₁ on the pH of the hydrothermal humification system and the artificial humic acid production rate;

Table 1

pH Yield A-HA _24h 6.96 6.77% Fe-AHA _6h 6.57 14.08%

The element composition of the artificial humic acid (Fe-AHA _6h ) prepared in Example 1 and the artificial humic acid (A-HA _24h ) prepared in Comparative Example 1 is listed in Table 2;

Table 2

It can be seen from Table 2 that after the hydrothermal humification reaction, the carbon mass fraction of corn stalks increased from 38% to 63.73% and 58.00%, respectively, and the oxygen mass fraction decreased from 54.68% to 28.59% and 35.49%, indicating that the hydrothermal humification process is A polycarbonate process. The element ratio indicates a certain type of chemical reaction, and the change of H/C ratio can reflect the _dehydration reaction that occurred during the _hydrothermal treatment. It shows that Fe-AHA _6h has the same high aromaticity as A-HA _24h , adding FeCl ₃ greatly accelerates the hydrothermal humification process.

Fig. 1 is the picture that is artificial humic acid surface functional group, among the figure 1 is the artificial humic acid Fe-AHA _6h that embodiment 1 prepares, and 2 is the artificial humic acid A-HA _24h that comparative example 1 prepares;

It can be seen from Figure 1 that the functional group richness of Fe-AHA _6h obtained in Example 1 is basically the same as that of the product A-HA _24h in Comparative Example 1, and the broad absorption band at 3420cm ^-1 is caused by the stretching of the -OH group. vibration, and the peak at 1690-1720cm ^-1 may be caused by the stretching vibration of the C=O bond of -COOH and the ketone group, and strong absorption peaks appeared at 1612cm ^-1 and 834cm ^-1 , It can be attributed to the vibration of aromatic C=O and aromatic CH, indicating that A-HA prepared by Fe ³⁺ catalyzed hydrothermal humification method also has an aromatic structure.

Fig. 2 is the solid-state ¹³ C nuclear magnetic resonance spectrogram of the artificial humic acid prepared by embodiment 1 and comparative example 1, among the figure 1 is the artificial humic acid Fe-AHA _6h prepared by embodiment 1, and 2 is prepared by comparative example 1 Artificial humic acid A-HA _24h ;

It can be seen from Fig. 2 that the carbon spectrogram shapes of the Fe-AHA _6h obtained in Example 1 and the product A-HA _24h of Comparative Example 1 are basically consistent, and the significant signal at 54ppm can be assigned to the methoxyl group, indicating that lignin is The main aromatic structure in artificial humic acid is determined by the composition of raw materials.

Fig. 3 is the three-dimensional fluorescence spectrogram of the liquid artificial humic acid prepared by comparative example 1;

Fig. 4 is the three-dimensional fluorescence spectrogram of the liquid artificial humic acid prepared in embodiment 1;

As can be seen from Fig. 3 and Fig. 4: the center position of the acid fluorescence intensity of the Fe-AHA _6h that embodiment 1 obtains and comparative example 1 product A-HA _24h all appear in Em=410-480nm, Ex=300-360nm, show Fe-AHA _6h and A-HA _24h have similar fluorescence characteristics, and their main components are humic acid substances.

Example 2: The difference between this example and Example 1 is that the hydrothermal reaction time is 0.5h, 1h, 2h, 4h, 6h, 12h or 24h. Other steps and parameters are all the same as in Example 2.

Comparative Example 2: The difference between this example and Comparative Example 2 is that the hydrothermal reaction time is 0.5h, 1h, 2h, 4h, 6h, 12h or 24h. Other steps and parameters are the same as in Comparative Example 2.

Fig. 5 is the precursor small molecule glucose concentration of the artificial humic acid in the hydrothermal humification process of embodiment 2 and comparative example 2 changes figure with reaction time, among the figure 1 is the artificial humic acid Fe- prepared by embodiment 1 AHA _6h , 2 is the artificial humic acid A-HA _24h that comparative example 1 prepares;

It can be seen from Figure 5 that without adding Fe ³⁺ , the glucose concentration gradually increased from 0.5 to 4 hours, and gradually decreased from 4 to 24 hours, but remained at 1304.37 mg/L at the end of the reaction, indicating that glucose was in the played an important role in the process of hydrothermal humification. During the hydrothermal humification process catalyzed by Fe ³⁺ , the glucose concentration reached the maximum at 0.5h, which was 82.47% higher than that without iron, and then decreased slowly.

Fig. 6 is the variation diagram of the concentration of the precursor small molecule 5-hydroxymethylfurfural of artificial humic acid in the hydrothermal humification process of embodiment 2 and comparative example 2 with the reaction time, and among the figure 1 is the artificial humic acid prepared by embodiment 1. Humic acid Fe-AHA _6h , 2 is the artificial humic acid A-HA _24h that comparative example 1 prepares;

As can be seen from Figure 6: in the absence of Fe ³⁺ , the concentration of 5-HMF is the same as that of glucose, showing a trend of first increasing and then decreasing, reaching the maximum concentration (54.58mg/L) at 4h. Under the catalysis of Fe ³⁺ , the concentration of 5-HMF reached the maximum (64.11mg/L) at 0.5h, and then gradually decreased with time. These results indicated that the Fe ³⁺ catalyzed hydrothermal humification process greatly promoted the hydrolysis of cellulose and produced a large amount of artificial humic acid precursors in a short period of time, thereby accelerating the humification of corn stover.

Application example 1:

The artificial humic acid (Fe-AHA _6h ) obtained in Example 1 was used to remove lead in water, and the artificial humic acid A-HA _24h obtained in Example 1 was compared. In the experiment, 10mg of artificial humic acid (Fe-AHA _6h and A-HA _24h ) were placed in 50mL Erlenmeyer flasks, and then 40mL of lead-containing wastewater with a lead ion concentration of 50mg/L was added. Put it in a shaker, shake at 150r/min and room temperature (25±1°C) for 0.16, 0.5, 1, 2, 4, 6, 8, 12 and 24 hours respectively, and measure the lead concentration in the solution after the reaction. The adsorption results are shown in Figure 7.

Fig. 7 is the adsorption figure of artificial humic acid to lead in application example 1, among the figure 1 is the artificial humic acid Fe-AHA _6h that embodiment 1 prepares, and 2 is the artificial humic acid A-HA _24h that comparative example 1 prepares .

Can draw from Fig. 7 that the Fe-AHA _6h that embodiment 1 prepares is directly used in the removal maximum capacity of lead in lead-containing waste water is 141.24 (Pb) mg/g, reaches adsorption equilibrium in 8 hours, and comparative example 1 prepares The maximum capacity of A-HA for the removal of lead ions was 88.30(Pb)mg/g _{in 24h} , and reached adsorption equilibrium in 6 hours.

Claims (10)

1. a kind of iron ion catalysis promotes the method for the synthetic humus of biomass humification, it is characterized in that comprising the steps: 1. Crushing the biomass, transferring the pulverized biomass to the reactor, then adding alkali, iron ion catalyst and water into the reactor, stirring evenly, and performing a closed hydrothermal reaction; 2. The product after the hydrothermal reaction is subjected to solid-liquid separation, and then the humus is recovered from the solid product and the liquid product respectively. 2. a kind of iron ion catalysis according to claim 1 promotes the method for biomass humification synthesis artificial humus, it is characterized in that the biomass described in step 1 is straw, trees, agricultural products produced in the agricultural and forestry production process One or a mixture of leftovers from processing industry, agricultural and forestry waste, poultry manure and waste from animal husbandry production. 3 . A method for iron ion catalysis to promote the humification of biomass to synthesize artificial humus according to claim 1 , characterized in that in step 1, a crusher is used to crush the biomass into fine pieces with a diameter of 0.1 to 2 cm. 4. a kind of iron ion catalysis according to claim 1 promotes the method for the synthetic humus of biomass humification, it is characterized in that the alkali described in step 1 is one or more in sodium hydroxide, potassium hydroxide kind. 5. a kind of iron ion catalysis according to claim 1 promotes the method for the synthetic humus of biomass humification, it is characterized in that the mass ratio of the alkali described in step 1 and the pulverized biomass is 1:(1～ 10). 6. a kind of iron ion catalysis according to claim 1 promotes the method for the synthetic humus of biomass humification, it is characterized in that the iron ion catalyst described in step 1 is ferric chloride, ferric sulfate and ferric nitrate One or more mixtures; the mass ratio of the iron ion catalyst described in step one to the pulverized biomass is 1:(5～20). 7. a kind of iron ion catalysis according to claim 1 promotes the method for the synthetic humus of biomass humification, it is characterized in that the mass ratio of the water described in step 1 and the pulverized biomass is 1g:(6mL～ 15mL). 8. A method for iron ion catalysis to promote the humification of biomass to synthesize artificial humus according to claim 1, characterized in that the temperature of the hydrothermal reaction described in step 1 is 180°C to 220°C, and the hydrothermal reaction The time is 2h ~ 20h. 9. a kind of iron ion catalysis according to claim 1 promotes the method for the synthetic humus of biomass humification, it is characterized in that the solid-liquid separation described in step 2 is to adopt the mode separation of centrifugation or filtration, the liquid obtained The product is directly used as a liquid fertilizer or humic acid is extracted by acid analysis to obtain solid humic acid; the obtained solid product is washed to neutrality and dried to obtain a humic product, which is used as a soil improvement application. 10. the method for a kind of iron ion catalysis promoting biomass humification synthesis artificial humus according to claim 1, it is characterized in that described solid humic acid is used for the removal of lead ion in lead-containing wastewater.