Multi-mesoporous biological filler containing oxygen-enriched functional groups as well as preparation method and application of multi-mesoporous biological filler

Abstract

The invention discloses a multi-mesoporous biological filler containing oxygen-enriched functional groups as well as a preparation method and application of the multi-mesoporous biological filler. The preparation method comprises the following steps: (1) stirring and mixing filler, ammonium salt and water; heating and stirring the mixed solution until moisture is completely evaporated to obtain a first solid material; drying the first solid material to obtain a precursor I; (2) calcining the precursor I in the presence of protective gas to obtain a precursor II; (3) mixing the precursor II, a surface modifier and water; heating and stirring the mixed solution until moisture is completely evaporated to obtain a second solid material; drying the second solid material to obtain a precursor III; and (4) calcining the precursor III to obtain the multi-mesoporous biological filler containing the oxygen-enriched functional group. The filler disclosed by the invention is beneficial to growth and enrichment of functional microorganisms and further beneficial to improvement of the treatment effect of degradation-resistant organic wastewater.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment, and more specifically, relates to a multi-mesoporous biological filler containing oxygen-rich functional groups, and a preparation method and application thereof. Background Art

[0002] The activated sludge method is currently the main treatment method in water treatment processes. Compared with physical and chemical methods such as adsorption, coagulation, and advanced oxidation, it has obvious economic advantages. However, when treating high-concentration organic wastewater, the degradation effect is poor due to the insufficient abundance of relevant functional microorganisms in the activated sludge. In order to solve these problems, researchers have enhanced the treatment effect by providing fillers for microbial attachment. However, parameters such as the specific surface area and pore size distribution of the filler have a significant effect on the microbial enrichment effect. Fillers rich in microporous structures have a larger specific surface area and more microbial attachment sites, but microbial attachment will cause blockage of micropores and reduce mass transfer efficiency; fillers rich in macroporous structures can ensure the mass transfer efficiency after microbial attachment, but compared with microporous and mesoporous structures, their specific surface area is usually smaller, which reduces the attachment sites of microorganisms; therefore, mesoporous structure materials that take into account both mass transfer efficiency and microbial growth sites have become a research hotspot and are ideal fillers for solving insufficient microbial biomass. In addition, problems such as the non-selectivity of microbial enrichment also limit the degradation effect of functional microorganisms on organic matter. Summary of the invention

[0003] The purpose of the present invention is to provide a multi-mesoporous biological filler containing oxygen-rich functional groups and a preparation method and application thereof. The filler of the present invention has a mesoporous structure and contains oxygen-rich functional groups, which is conducive to the growth and enrichment of functional microorganisms, and further helps to improve the treatment effect of difficult-to-degrade organic wastewater.

[0004] In order to achieve the above-mentioned object, the first aspect of the present invention provides a method for preparing a mesoporous biological filler containing oxygen-rich functional groups, characterized in that the preparation method comprises:

[0005] (1) stirring and mixing a filler, an ammonium salt and water; then heating and stirring the mixture until the water in the mixture is completely evaporated to obtain a first solid material; drying the first solid material to obtain a precursor 1;

[0006] (2) calcining the precursor 1 in the presence of a protective gas to obtain a precursor 2;

[0007] (3) mixing the precursor 2, the surface modifier and water; then heating and stirring the mixture until the water in the mixture is completely evaporated to obtain a second solid material; drying the second solid material to obtain a precursor 3;

[0008] (4) calcining the precursor three to obtain the mesoporous biofiller containing oxygen-rich functional groups.

[0009] According to the present invention, preferably, in step (1), the filler comprises: the filler comprises: at least one of wood activated carbon, coal-made activated carbon and carbon nitride material; preferably coconut shell activated carbon;

[0010] The particle size of the filler is less than 8 meshes.

[0011] According to the present invention, preferably, in step (1), the ammonium salt is ammonium chloride and / or ammonium bicarbonate.

[0012] According to the present invention, preferably, in step (1), the mass ratio of the filler to the ammonium salt is 1:(0.1-0.5);

[0013] The volume ratio of the water to the filler is (3.0-5.0):1;

[0014] The heating and stirring temperature is 80°C-90°C;

[0015] The drying temperature is 75-85°C and the drying time is 10-15h.

[0016] In the present invention, preferably, in step (1), the mixed solution is placed in a water bath for heating and stirring, and the water bath temperature is 80°C-90°C.

[0017] According to the present invention, preferably, in step (2), the calcination conditions include: heating to 450°C-600°C at a heating rate of 0.5°C / min-2.0°C / min, and then maintaining at 450°C-600°C for 1.5-3h;

[0018] Preferably, the precursor 1 is spread flat in an uncovered porcelain boat with a thickness of less than 0.5 cm, and then the uncovered porcelain boat is placed in a tubular furnace for heating. The tubular furnace is heated to 450°C-600°C at a heating rate of 0.5°C / min-2.0°C / min, and then maintained at 450°C-600°C for 1.5-3h to obtain precursor 2; wherein, during the heating process, a protective gas is continuously introduced into the tubular furnace, and the protective gas is preferably nitrogen.

[0019] In the present invention, preferably, there are one or more uncovered porcelain boats.

[0020] According to the present invention, preferably, in step (3), the surface modifier is at least one of nitric acid, tributyl phosphate, ubiquinone and borohydride.

[0021] According to the present invention, preferably, in step (3), the mass ratio of the second precursor to the surface modifier is 1:(1.0-1.7);

[0022] The volume ratio of the water to the second precursor is (2.5-1.0):1;

[0023] The heating and stirring temperature is 80°C-90°C;

[0024] The drying temperature is 110-130° C. and the drying time is 20-25 hours.

[0025] In the present invention, preferably, in step (3), the mixed solution is placed in a water bath for heating and stirring, and the water bath temperature is 80°C-90°C.

[0026] According to the present invention, preferably, in step (4), the calcination conditions include: heating to 550°C-650°C at a heating rate of 2-5°C / min, and then maintaining at 550°C-650°C for 2.5-4h;

[0027] Preferably, the precursor is transferred to a covered crucible, and then heated in a muffle furnace at a heating rate of 2-5°C / min to 550°C-650°C, and then maintained at 550°C-650°C for 2.5-4h to obtain the mesoporous biofiller containing oxygen-rich functional groups.

[0028] In the present invention, under the combined action of high temperature, surface modifier and oxygen, the oxygen-containing functional groups such as carboxyl, hydroxyl and carbonyl on the surface of the filler gradually increase, providing active sites for the attachment of aerobic microorganisms.

[0029] The second aspect of the present invention provides a mesoporous biofiller containing oxygen-rich functional groups prepared by the above preparation method.

[0030] The third aspect of the present invention provides the use of the above-mentioned mesoporous biological filler containing oxygen-rich functional groups in treating organic wastewater.

[0031] The technical solution of the present invention has the following beneficial effects:

[0032] (1) The filler of the present invention has a mesoporous structure and contains oxygen-rich functional groups, which is conducive to the growth and enrichment of functional microorganisms, thereby helping to improve the treatment effect of difficult-to-degrade organic wastewater.

[0033] (2) In the present invention, the micropore walls of the filler are corroded by the decomposition products of ammonium salts at appropriate concentrations under high temperature conditions, so that the pore diameter of part of the filler is expanded to the mesoporous range. The mesoporous structure can provide good air permeability and the flow of nutrients, which is conducive to the growth and enrichment of functional microorganisms.

[0034] (3) In the present invention, under the combined action of surface modifier, high temperature and oxygen, the functional group composition on the surface of the filler changes, and the number of oxygen-containing functional groups such as carboxyl, hydroxyl and carbonyl increases, which is conducive to the enrichment and growth of aerobic microorganisms such as Bacillus, Blastocatellaceae and Acidobacillus on the surface of the filler, thereby increasing the abundance of functional microorganisms in a unit volume of filler, thereby improving the treatment effect of difficult-to-degrade organic wastewater.

[0035] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0037] Figure 1 A physical diagram of a mesoporous biofiller containing oxygen-rich functional groups according to an embodiment of the present invention is shown.

[0038] Figure 2 The pore size distribution diagram of Test Example 1 of the present invention is shown; wherein the vertical axis represents the change in pore volume within a unit pore size.

[0039] Figure 3 The FT-IR spectrum of Test Example 1 of the present invention is shown.

[0040] Figure 4 A graph showing changes in relative abundance of bacterial flora in Test Example 2 of the present invention is shown.

[0041] Figure 5 The organic matter removal effect diagram of Test Example 3 of the present invention is shown. DETAILED DESCRIPTION

[0042] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0043] The present invention is further described below by examples:

[0044] Example

[0045] This embodiment provides a mesoporous biofiller containing oxygen-rich functional groups. The specific preparation method is as follows: 500.0 g coconut shell activated carbon (particle size 8-30 mesh, bulk density of about 0.5 t / m 3) and 200.0g of ammonium chloride are added to 5.0L of deionized water and stirred for 1h, then the mixture is transferred to a water bath, and continued to stir in a water bath at 80°C until the water is completely evaporated. The remaining solid (the first solid material) is placed in an oven at 80°C and continued to dry for 12h to obtain a precursor 1. Precursor 1 is spread in multiple 12cm*6cm uncovered porcelain boats with a paving thickness of 0.3cm. Multiple uncovered porcelain boats are transferred to a tubular furnace, and nitrogen (purity>99%, flow rate 100mL / min) is introduced. The tubular furnace is heated to 550°C at a heating rate of 1°C / min and maintained for 2h. After the heating is completed, it is naturally cooled to room temperature to obtain a precursor 2 containing a rich mesoporous structure.

[0046] 200.0 g of the precursor 2 and 208.4 ml of 98% nitric acid were added to 800.0 ml of deionized water and mixed for 30 min. The mixture was then placed in a high-temperature water bath at 80° C. and stirred continuously. After the water was completely evaporated, the remaining solid (the second solid material) was placed in an oven at 120° C. and continued to dry for 24 h. The dried solid was then placed in a covered crucible and heated in a muffle furnace at a heating rate of 4° C. / min to 600° C. and maintained for 3 h. After cooling to room temperature, the final mesoporous biofiller containing oxygen-rich functional groups (biofiller 1, such as Figure 1 shown).

[0047] Test Example 1

[0048] The raw material coconut shell activated carbon used in the example and the mesoporous biofiller containing oxygen-rich functional groups prepared in the example were subjected to BET test and Fourier transform infrared spectroscopy test. The specific test results are shown in Table 1. Figure 2 and Figure 3 .

[0049] Table 1: BET test

[0050]

[0051] As shown in Table 1 and Figure 2 As shown, compared with the initial coconut shell activated carbon, the number of micropores of the biofiller 1 prepared in Example 1 decreased, the number of mesopores increased, and the total average pore diameter and the average pore diameter of the mesopores increased from 1.9615 nm and 2.7997 nm to 2.2052 nm and 3.6243 nm, respectively; Figure 3 As shown, compared with coconut shell activated carbon, the biofiller prepared in Example 1 has a -1 With 3500cm -1 The FT-IR peak intensity at the position was significantly enhanced, confirming that the number of oxygen-containing functional groups such as carboxyl and hydroxyl groups increased significantly.

[0052] Test Example 2

[0053] The biofiller 1 prepared in Example 1 was tested for functional microbial enrichment and performance optimization of difficult-to-degrade organic matter removal. After implementation, the abundance of functional microorganisms increased significantly. The results are as follows: Figure 4 As shown in the figure, the removal rate of refractory organic matter is significantly improved. Figure 5 shown.

[0054] Specifically, the test was carried out in the form of a continuous flow aerated biological filter reactor. The seed sludge in the reactor was inoculated with return sludge from an A2O process in Beijing, and the sludge digestion liquid wastewater was used as the treatment object. 400g of biological filler 1 was added to the reactor of the experimental group, no filler was added to the reactor of the control group 1, and 400g of initial coconut shell activated carbon (the raw coconut shell activated carbon used in the embodiment) was added to the reactor of the control group 2. The effective hydraulic retention time in the three groups of reactors was 4h, the aeration volume was 0.6L / min, and the other operating conditions were exactly the same.

[0055] After 90 days of operation, the microorganisms in the three groups of reactors were sequenced by high-throughput sequencing. Figure 4 As shown in the figure, compared with ordinary coconut shell activated carbon, biological filler 1 is more conducive to the growth and enrichment of Bacillus, Blastocatellaceae, and Acidobacteria. The removal effect of refractory organic matter was evaluated by COD index. The results are shown in the figure. Figure 5 As shown, within 90 days of operation, the maximum and average COD removal rates of the test group were 55.5% and 49.0%, respectively, while the maximum and average COD removal rates of the control group 2 were 32.8% and 24.6%, respectively. Due to the extremely low abundance of functional bacteria in the control group 1, there was no organic matter removal effect in this group.

[0056] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for preparing a mesoporous biofiller containing oxygen-rich functional groups, characterized in that: The preparation method comprises: (1) stirring and mixing a filler, an ammonium salt and water; then heating and stirring the mixture until the water in the mixture is completely evaporated to obtain a first solid material; drying the first solid material to obtain a precursor 1; (2) calcining the precursor 1 in the presence of a protective gas to obtain a precursor 2; (3) mixing the precursor 2, the surface modifier and water; then heating and stirring the mixture until the water in the mixture is completely evaporated to obtain a second solid material; drying the second solid material to obtain a precursor 3; (4) calcining the precursor three to obtain the mesoporous biofiller containing oxygen-rich functional groups.

2. The preparation method according to claim 1, wherein In step (1), the filler comprises: at least one of wood activated carbon, coal-made activated carbon and carbon nitride material; preferably coconut shell activated carbon; The particle size of the filler is less than 8 meshes.

3. The preparation method according to claim 1, wherein In step (1), the ammonium salt is ammonium chloride and / or ammonium bicarbonate.

4. The preparation method according to claim 1, wherein In step (1), the mass ratio of the filler to the ammonium salt is 1:(0.1-0.5); The volume ratio of the water to the filler is (3.0-5.0):1; The heating and stirring temperature is 80°C-90°C; The drying temperature is 75-85°C and the drying time is 10-15h.

5. The preparation method according to claim 1, wherein In step (2), the calcination conditions include: heating to 450°C-600°C at a heating rate of 0.5°C / min-2.0°C / min, and then maintaining at 450°C-600°C for 1.5-3h; Preferably, the precursor 1 is spread flat in an uncovered porcelain boat with a thickness of less than 0.5 cm, and then the uncovered porcelain boat is placed in a tubular furnace for heating. The tubular furnace is heated to 450°C-600°C at a heating rate of 0.5°C / min-2.0°C / min, and then maintained at 450°C-600°C for 1.5-3h to obtain precursor 2; wherein, during the heating process, a protective gas is continuously introduced into the tubular furnace, and the protective gas is preferably nitrogen.

6. The preparation method according to claim 1, wherein In step (3), the surface modifier is at least one of nitric acid, tributyl phosphate, ubiquinone and borohydride.

7. The preparation method according to claim 1, wherein In step (3), the mass ratio of the precursor 2 to the surface modifier is 1:(1.0-1.7); The volume ratio of the water to the second precursor is (2.5-1.0):1; The heating and stirring temperature is 80°C-90°C; The drying temperature is 110-130° C. and the drying time is 20-25 hours.

8. The preparation method according to claim 1, wherein In step (4), the calcination conditions include: heating to 550°C-650°C at a heating rate of 2-5°C / min, and then maintaining at 550°C-650°C for 2.5-4h; Preferably, the precursor is transferred to a covered crucible, and then heated in a muffle furnace at a heating rate of 2-5°C / min to 550°C-650°C, and then maintained at 550°C-650°C for 2.5-4h to obtain the mesoporous biofiller containing oxygen-rich functional groups.

9. A mesoporous biofiller containing oxygen-rich functional groups prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the mesoporous biological filler containing oxygen-rich functional groups as claimed in claim 9 in treating organic wastewater.

Images