Method for improving anaerobic fermentation efficiency of organic waste

Abstract

The invention relates to a method for improving the anaerobic fermentation efficiency of organic waste, and belongs to the technical field of waste resource reutilization, and the specific operation is as follows: firstly, crushing and uniformly mixing the organic waste to obtain an anaerobic fermentation substrate, then mixing a white-rot fungus fermentation product, cellulase and an acetic acid-sodium acetate buffer solution to obtain a solution A, and then adding the solution B to obtain a solution C; the organic metal framework material and the solution A are mixed according to the mass ratio of 2: 1 and fully stirred, a compound is obtained, finally, the compound is subjected to vacuum freeze drying treatment, finally, the pretreated organic metal framework material and an anaerobic fermentation substrate are evenly mixed, and anaerobic fermentation is conducted, and the organic metal framework material is one of a UiO-66 series, an MOF-808 series and an MIL-101 series. According to the method for improving the anaerobic fermentation efficiency, an anaerobic fermentation system containing the catalyst is adopted, and when waste resources are recycled through fermentation treatment, PTA-MIL-101-Br contained in the catalyst can effectively improve the fermentation efficiency and the methane output.

Description

Technical Field

[0001] The invention belongs to the technical field of waste resource recycling technology, and specifically relates to a method for improving the anaerobic fermentation efficiency of organic waste. Background Art

[0002] Anaerobic fermentation is an effective way to convert organic waste into bioenergy (such as methane) and stable biofertilizer. However, due to their complex structure and stability, macromolecular organic matter such as cellulose, hemicellulose, and protein in organic waste is often difficult to be directly utilized by anaerobic microorganisms, which limits the efficiency of anaerobic fermentation and product quality.

[0003] Organic metal framework materials have unique structures and properties, such as high specific surface area, adjustable pore structure and highly ordered crystal structure, and thus can provide uniform catalytic sites, showing great application potential in the field of catalysis. Especially in the field of biocatalysis, organic metal framework materials (MOFs) can not only serve as effective catalysts, but also accelerate chemical reactions and improve reaction rates and selectivity.

[0004] At present, the catalyst commonly used to improve the anaerobic fermentation rate is mainly a biocatalyst. However, the catalytic activity of the biocatalyst is easily destroyed and inactivated by heat, chemicals and bacteria, and the stability is poor. Based on the defects of the existing anaerobic fermentation method and the performance characteristics of the organic metal framework material, the present invention proposes a method for improving the anaerobic fermentation efficiency of organic waste. Summary of the invention

[0005] The purpose of the present invention is to provide a method for improving the anaerobic fermentation efficiency of organic waste in order to solve the above problems.

[0006] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0007] The present invention provides a method for improving the anaerobic fermentation efficiency of organic waste, comprising the following steps:

[0008] (1) crushing and mixing organic waste to obtain anaerobic fermentation substrate;

[0009] (2) The organic metal framework material is evenly mixed with the anaerobic fermentation substrate and then subjected to anaerobic fermentation.

[0010] As a further optimization scheme of the present invention, the organic metal framework material is one of the UiO-66 series, MOF-808 series and MIL-101 series.

[0011] As a further optimization scheme of the present invention, the organic metal framework material is one of UIO-66-NH2, MOF-808 (Zr) and PTA-MIL-101-Br.

[0012] As a further optimization scheme of the present invention, the organic metal framework material is PTA-MIL-101-Br.

[0013] As a further optimization scheme of the present invention, in step (2), the organic metal framework material is pretreated and then mixed with the anaerobic fermentation substrate. The specific operation of the pretreatment is: mixing the white rot fungus fermentation product, cellulase and acetic acid-sodium acetate buffer solution to obtain solution A, mixing the organic metal framework material and solution A at a mass ratio of 2:1 and fully stirring to obtain a composite, and finally subjecting the composite to vacuum freeze-drying treatment.

[0014] As a further optimization scheme of the present invention, in solution A, the mixing ratio of the raw materials is 200-350 ml of white rot fungus fermentation product and 300-500 ml of acetic acid-sodium acetate buffer solution per 300 ml of cellulase solution.

[0015] As a further optimization scheme of the present invention, the mixing mass ratio of the organic metal framework material to the anaerobic fermentation substrate is (1-3):100.

[0016] As a further optimization scheme of the present invention, the organic waste is one or more of crop straw, livestock and poultry manure, food processing waste and urban organic waste.

[0017] As a further optimization scheme of the present invention, the anaerobic fermentation efficiency specifically refers to methane production efficiency, output peak value and total output.

[0018] The beneficial effects of the present invention are:

[0019] The method for improving the efficiency of anaerobic fermentation achieves the effect of improving the efficiency of anaerobic fermentation and improving the quality of anaerobic fermentation products based on an anaerobic fermentation system containing PTA-MIL-101-Br. In the anaerobic fermentation system, on the one hand, PTA-MIL-101-Br itself can achieve a significant catalytic effect, which can effectively improve the methane output efficiency, output peak and total output of the anaerobic fermentation system. On the other hand, PTA-MIL-101-Br also acts as a carrier of a mixture of white rot fungus fermentation products, cellulase and acetic acid-sodium acetate buffer solution, which is beneficial to improving the distribution uniformity of the catalyst in the anaerobic fermentation substrate, further enhancing the effectiveness of the catalyst in the anaerobic fermentation system, and achieving a more efficient and higher-yield anaerobic fermentation effect. DETAILED DESCRIPTION

[0020] The present application is described in further detail below. It is necessary to point out that the following specific implementation methods are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Technicians in this field can make some non-essential improvements and adjustments to the present application based on the above application content.

[0021] 1. Materials

[0022] Unless otherwise specified, the methods used in the present invention are conventional methods known to those skilled in the art, and the reagents and other materials used are commercially available products unless otherwise specified.

[0023] The preparation method of PTA-MIL-101-Br in the present invention is as follows: 2mmol FeCl3·6H2O, 1mmol 2-bromoterephthalic acid, 1mmol terephthalic acid and 0.08mmol phosphotungstic acid are mixed and put into a DMF solution, and a one-pot method is used to perform a heating treatment for 16 hours at a heating temperature of 110°C, and then a solid product is separated by a centrifuge, and the solid product is washed with a DMF solution at room temperature, and then the washed solid product is vacuum dried at a drying temperature of 80°C, and PTA-MIL-101-Br is obtained after the drying is completed;

[0024] The mass fraction of cellulase in the cellulase solution used is 1%, and the cellulase is prepared before use.

[0025] The concentration of acetic acid-sodium acetate buffer used was 0.05 mol / L and the pH value was 4.3;

[0026] The method for preparing the white rot fungus fermentation product is as follows: inoculating the white rot fungus (specifically, Phanerochaete chrysosporium) into a fermentation medium for full fermentation, filtering the fermentation product, and using the filtrate as the white rot fungus fermentation product, wherein the fermentation medium includes 2 g / L of glucose, 40 g / L of wheat bran, 1 g / L of urea, 3 g / L of (NH4)2SO4, 2 g / L of peptone, 3 g / L of KH2PO4, 0.4 g / L of CaCl2, 0.01 g / L of FeSO4, and 0.004 g / L of MnSO4, and the balance is water;

[0027] The UIO-66-NH2 used was purchased from Jiangsu Xianfeng Nanomaterial Technology Co., Ltd., and MOF-808 (Zr) was purchased from Xi'an Qiyue Biology.

[0028] 2. Methods

[0029] 1. Effect of organic metal framework materials on anaerobic fermentation efficiency

[0030] Example 1

[0031] (1) 30 g of straw and 30 g of pig manure were crushed and evenly mixed, and then 500 ml of sterile water was added and further mixed to obtain an anaerobic fermentation substrate;

[0032] (2) PTA-MIL-101-Br and anaerobic fermentation substrate were uniformly mixed at a mass ratio of 1:100 and then anaerobic fermentation was carried out at a fermentation temperature of 30°C.

[0033] The anaerobic fermentation system obtained in Example 1 is marked as A. Based on the method of Example 1, anaerobic fermentation systems B and C are prepared. The only difference is that UIO-66-NH2 and MOF-808 (Zr) are used in turn instead of PTA-MIL-101-Br as the selected organic metal materials.

[0034] Blank example

[0035] 30 g of straw and 30 g of pig manure were crushed and evenly mixed, and then 500 ml of sterile water was added and further mixed to obtain an anaerobic fermentation substrate, and anaerobic fermentation was performed at a fermentation temperature of 30°C;

[0036] The fermentation process of the fermentation systems AC in Example 1 and the anaerobic fermentation system in the blank example was monitored. The specific monitoring method was to collect the gas produced during the fermentation process every 5 days during the 90-day fermentation period and measure the methane content therein by gas chromatography. The results are shown in the following table:

[0037]

[0038] From the table above we can see that:

[0039] In Example 1, the total amount of gas and methane production produced by fermentation systems A, B, and C are better than those of the blank example, and the gas production peak is reached faster. When the gas production reaches the peak, the methane production in the gas is also higher. This result shows that the use of organic metal framework materials such as UIO-66-NH2, MOF-808 (Zr) and PTA-MIL-101-Br can improve the anaerobic fermentation efficiency of organic waste and increase the proportion of methane in the gas fermentation product. Further comparison of the corresponding data of A, B, and C shows that compared with UIO-66-NH2 and MOF-808 (Zr), PTA-MIL-101-Br can further prolong the duration of the gas production peak, which is beneficial to further increase the methane output, and comprehensively achieves the effect of improving the methane production efficiency, output peak and total output during anaerobic fermentation.

[0040] 2. Effect of solution A on anaerobic fermentation efficiency

[0041] Example 2

[0042] (1) 30 g of straw and 30 g of pig manure were crushed and evenly mixed, and then 500 ml of sterile water was added and further mixed to obtain an anaerobic fermentation substrate;

[0043] (2) Pretreatment of PTA-MIL-101-Br: 200 ml of white rot fungus fermentation product, 300 ml of cellulase solution and 500 ml of acetic acid-sodium acetate buffer solution were mixed to obtain solution A, PTA-MIL-101--Br and solution A were mixed at a mass ratio of 2:1 and fully stirred to obtain a composite, and finally the composite was subjected to vacuum freeze-drying treatment for 24 hours at a treatment temperature of 35°C;

[0044] (3) The pretreated PTA-MIL-101--Br and the anaerobic fermentation substrate were uniformly mixed at a mass ratio of 3:100 and then anaerobic fermentation was carried out at a fermentation temperature of 30°C.

[0045] The anaerobic fermentation system obtained in Example 2 is marked as D. Based on the method of Example 2, an anaerobic fermentation system E is prepared, except that the raw material composition of solution A in step (2) is adjusted to: 350 ml of white rot fungus fermentation product, 300 ml of cellulase solution and 300 ml of acetic acid-sodium acetate buffer solution;

[0046] Based on the method of Example 2, anaerobic fermentation systems F and G were prepared, the only difference being that UIO-66-NH2 and MOF-808 (Zr) were used in turn to replace PTA-MIL-101-Br as the selected organic metal materials.

[0047] Comparative Example 1

[0048] 200 ml of white rot fungus fermentation product, 300 ml of cellulase solution and 500 ml of acetic acid-sodium acetate buffer solution were mixed to obtain solution A, and solution A was subjected to vacuum freeze-drying treatment for 24 hours at a treatment temperature of 35°C. The product obtained after freeze-drying treatment was uniformly mixed with an anaerobic fermentation substrate at a mass ratio of 3:100, and then anaerobic fermentation was carried out at a fermentation temperature of 30°C.

[0049] The fermentation process of the fermentation system DG in Example 2 and the anaerobic fermentation system in Comparative Example 1 was monitored. The specific monitoring method was to collect the gas produced during the fermentation process every 5 days during the 90-day fermentation period, and measure the methane content therein with a gas chromatograph. Based on the obtained data, the gas permeation law and the methane output law during the 90-day fermentation period were further calculated. The results are shown in the following table:

[0050]

[0051]

[0052] Based on the data in the above table, the following conclusions are drawn:

[0053] 1. Compared with the fermentation system A in Example 1, D and F in Example 2 respectively introduced solutions A of different components into the fermentation system on the basis of A, while F and G respectively introduced solutions A of the same components into the fermentation system on the basis of B and C, which made the fermentation system produce gas more efficiently, with more peak output and total output. Correspondingly, the output efficiency, peak output and total output of methane were also better. This result shows that the introduction of solution A into the fermentation system based on the existing organic metal framework material can further improve the efficiency of anaerobic fermentation;

[0054] 2. In Example 2, the difference between D, E, and F lies in the different organic metal framework materials used. Through the comparison of the data of each group, it can be seen that when PTA-MIL-101-Br is used in combination with solution A, the best anaerobic fermentation effect can be obtained. Not only is the fermentation efficiency higher, the total gas output and methane output are more, and the proportion of methane in the output gas is significantly higher. Further running through the data of comparative example 1, the difference between comparative example 1 and the blank example is that the fermentation system of comparative example 1 contains solution A (the components are the same as solution A in D, F, and G). The results show that when only solution A is introduced into the fermentation system, it only has the effect of increasing the amount of gas output caused by fermentation. Comprehensive analysis shows that the combination of PTA-MIL-101-Br and solution A can effectively increase the proportion of methane in the gas produced by fermentation.

[0055] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A method for improving the anaerobic fermentation efficiency of organic waste, characterized in that: The following steps are involved: (1) crushing and mixing organic waste to obtain anaerobic fermentation substrate; (2) The organic metal framework material is uniformly mixed with the anaerobic fermentation substrate and then subjected to anaerobic fermentation to improve the anaerobic fermentation efficiency of the organic waste.

2. A method for improving the anaerobic fermentation efficiency of organic waste according to claim 1, characterized in that: The organic metal framework material is one of the UiO-66 series, MOF-808 series and MIL-101 series.

3. A method for improving the anaerobic fermentation efficiency of organic waste according to claim 2, characterized in that: The organic metal framework material is one of UIO-66-NH2, MOF-808 (Zr) and PTA-MIL-101-Br.

4. A method for improving the anaerobic fermentation efficiency of organic waste according to claim 3, characterized in that: The organic metal framework material is PTA-MIL-101-Br.

5. The method for improving the anaerobic fermentation efficiency of organic waste according to claim 1, characterized in that: In the step (2), the organic metal framework material is pretreated and then mixed with the anaerobic fermentation substrate. The specific operation of the pretreatment is: mixing the white rot fungus fermentation product, cellulase and acetic acid-sodium acetate buffer solution to obtain solution A, mixing the organic metal framework material and solution A at a mass ratio of 2:1 and fully stirring to obtain a composite, and finally performing vacuum freeze-drying on the composite.

6. A method for improving the anaerobic fermentation efficiency of organic waste according to claim 5, characterized in that: In the solution A, the mixing ratio of the raw materials is 200-350 ml of white rot fungus fermentation product and 300-500 ml of acetic acid-sodium acetate buffer solution per 300 ml of cellulase solution.

7. A method for improving the anaerobic fermentation efficiency of organic waste according to claim 1, characterized in that: The mixing mass ratio of the organic metal framework material to the anaerobic fermentation substrate is (1-3):

100.

8. The method for improving the anaerobic fermentation efficiency of organic waste according to claim 1, characterized in that: The organic waste is one or more of crop straw, livestock and poultry excrement, food processing waste and urban organic waste.

9. A method for improving the anaerobic fermentation efficiency of organic waste according to claim 1, characterized in that: The anaerobic fermentation efficiency specifically refers to methane production efficiency, output peak value and total output.

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