Citrus peel biomatrix material and preparation method and application thereof

Abstract

This invention discloses a citrus peel biomatrix material, its preparation method, and its application, belonging to the field of biomaterials technology. The preparation method of the citrus peel biomatrix material includes the following steps: soaking citrus peel in an acidic solution, then removing it and air-drying it to obtain a pretreated citrus peel material; soaking the pretreated citrus peel in a nutrient solution to obtain an intermediate citrus peel material; coating the surface of the intermediate citrus peel material with photosynthetic bacteria powder, then culturing it under light to obtain a composite citrus peel material; and coating the surface of the composite citrus peel material with a protective agent to obtain the citrus peel biomatrix material. The citrus peel biomatrix material of this invention can better remove organic pollutants from wastewater. Simultaneously, this citrus peel biomatrix material degrades slowly. Therefore, this citrus peel biomatrix material has good application prospects in wastewater treatment.

Description

Technical Field

[0001] This invention belongs to the field of biomaterials technology, specifically relating to a citrus peel biomatrix material, its preparation method, and its application. Background Technology

[0002] Currently, most domestic sewage treatment in China adopts the AAO (anaerobic, anoxic, and aerobic) water treatment process, and the treated sewage meets national standards for discharge. To improve water treatment efficiency, it is necessary to simultaneously remove chemical oxygen demand (COD), total nitrogen (TN), ammonia nitrogen (NH4-N), and total phosphorus (TP) from the water.

[0003] Chinese patent document CN116986718A discloses a novel packing material for enhancing wastewater denitrification, its preparation method, and biofilm formation method. The preparation method of this novel packing material includes modifying spent membrane fibers by soaking them in a sodium hypochlorite solution, immersing the spent membrane fibers in a coating solution containing reduced iron powder and dopamine hydrochloride, and drying to obtain the final modified membrane fibers. The novel packing material successfully reduces the water contact angle on the packing surface, enhances the biofilm enrichment capacity per unit membrane area, and significantly increases the unit denitrification rate of the biofilm on the packing surface.

[0004] While the existing matrix materials mentioned above can improve the denitrification effect of wastewater, they still have problems such as poor wastewater removal efficiency and the need for subsequent recycling and treatment of the matrix materials. Summary of the Invention

[0005] The purpose of this invention is to provide a citrus peel bio-matrix material, its preparation method, and its application. This addresses the problems of existing bio-matrix materials, such as poor wastewater removal efficiency and the need for subsequent recycling.

[0006] In a first aspect, the present invention provides a method for preparing a citrus peel biomatrix material, comprising the following steps: soaking citrus peel in an acidic solution, then removing it and air-drying it to obtain a citrus peel pretreated material; soaking the pretreated citrus peel in a nutrient solution to obtain a citrus peel intermediate material; coating the surface of the citrus peel intermediate material with photosynthetic bacteria powder, and then culturing it under light to obtain a citrus peel composite material; coating the surface of the citrus peel composite material with a protective agent to obtain a citrus peel biomatrix material; wherein the protective agent includes glycerol and / or ethanol.

[0007] In this invention, the inventors discovered that acid treatment of citrus peel increases pore diameter and porosity, which is beneficial for microbial colonization and also allows for better adsorption of organic matter in wastewater. Further, soaking the citrus peel in a nutrient solution and coating it with photosynthetic bacteria powder resulted in a citrus peel bio-matrix material that more efficiently removes organic pollutants from wastewater. Additionally, coating the surface of the citrus peel with a protective agent facilitates better colonization of photosynthetic bacteria, further enhancing the wastewater treatment capacity of this citrus peel bio-matrix material. Moreover, this citrus peel bio-matrix material degrades slowly; therefore, after using this material for wastewater treatment, there is no need to recycle the matrix material, resulting in no secondary pollution and solving the technical problem of the need for subsequent recycling of existing matrix materials.

[0008] In some embodiments, during the preparation of the citrus peel pretreatment material, the pH value of the acid solution is 3 to 4, for example, it can be 3.2, 3.4, 3.6, 3.8, 4 or other values ​​within this range; and the acid solution is selected from at least one of sulfuric acid solution, nitric acid solution and hydrochloric acid solution.

[0009] In this invention, the inventors further discovered that by controlling the pH value of the acid solution to 3-4, citrus peel with a suitable porosity can be obtained. If the pH of the acid solution is too low, the pores of the citrus peel will collapse or even degrade; if the pH of the acid solution is too high, the reaction will be incomplete, and the pores of the obtained citrus peel will be smaller.

[0010] In some implementations, the soaking process in the preparation of citrus peel pretreatment materials includes a soaking time of 1 to 3 hours, for example, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours or other values ​​within this range.

[0011] In some embodiments, during the preparation of the intermediate material from citrus peel, the nutrient solution includes: 0.8–1.2 g (e.g., 0.8 g, 0.9 g, 1 g, 1.1 g, 1.2 g, or other values ​​within this range) NH4Cl, 3–4 g (e.g., 3 g, 3.3 g, 3.5 g, 3.7 g, 4 g, or other values ​​within this range) CH3COONa, 0.05–0.15 g (e.g., 0.05 g, 0.07 g, 0.1 g, 0.13 g, 0.15 g, or other values ​​within this range) MgCl2, 0.05–0.15 g (e.g., 0.05 g, 0.07 g, 0.1 g, 0.13 g, 0.15 g, or other values ​​within this range) CaCl2, 0.5–0.7 g (e.g., 0.05 g, 0.07 g, 0.1 g, 0.13 g, 0.15 g, or other values ​​within this range) CaCl2, 0.5–0.7 g (e.g., 0.05 g, 0.07 g, 0.1 g, 0.13 g, 0.15 g, or other values ​​within this range) The following are considered as 0.5g, 0.55g, 0.6g, 0.65g, 0.7g or other values ​​within this range): KH2PO4, 0.3-0.5g (e.g., 0.3g, 0.35g, 0.4g, 0.45g, 0.5g or other values ​​within this range): K2HPO4, 0.05-0.15g (e.g., 0.05g, 0.07g, 0.1g, 0.13g, 0.15g or other values ​​within this range): yeast extract, 800-1200ml (e.g., 800ml, 900ml, 1000ml, 1100ml, 1200ml or other values ​​within this range): water, with a pH value of 7-7.4, e.g., 7, 7.1, 7.2, 7.3, 7.4 or other values ​​within this range.

[0012] In some preferred embodiments, the nutrient solution comprises: 1g NH4Cl, 3.5g CH3COONa, 0.1g MgCl2, 0.1g CaCl2, 0.6g KH2PO4, 0.4g K2HPO4, 0.1g yeast extract, 1000ml water, with a pH of 7.2.

[0013] In some implementations, the soaking process in the preparation of the citrus peel intermediate material includes a soaking time of 2 to 5 hours, for example, 2 hours, 3 hours, 4 hours, 5 hours or other values ​​within this range.

[0014] In some embodiments, during the preparation of the citrus peel composite material, the mass ratio of photosynthetic bacteria powder to citrus peel intermediate material is (0.5–1.5):2, for example, it can be 0.5:2, 0.7:2, 1:2, 1.3:2, 1.5:2 or other ratios within this range; and the photosynthetic bacteria are selected from at least one of purple sulfur bacteria, purple sulfur-free bacteria, green sulfur bacteria, and green sulfur-free bacteria.

[0015] In this invention, the photosynthetic bacteria can be selected from microorganisms commonly used in wastewater treatment in the field, and preferably selected from at least one of purple sulfur bacteria, purple sulfur-free bacteria, green sulfur bacteria, and green sulfur-free bacteria.

[0016] In some embodiments, during the preparation of the citrus peel composite material, light cultivation includes: cultivating for 3 to 7 days, for example, 3 days, 4 days, 5 days, 6 days, 7 days, or other values ​​within the range, under the following conditions: humidity of 70-90% (e.g., 70%, 75%, 80%, 85%, 90% or other values ​​within this range), temperature of 20-30°C (e.g., 20°C, 22°C, 24°C, 26°C, 28°C, 30°C or other values ​​within this range), and light intensity of 3500-4500 Lux (e.g., 3500 Lux, 3700 Lux, 4000 Lux, 4300 Lux, 4500 Lux or other values ​​within this range).

[0017] In some embodiments, during the preparation of the citrus peel biomatrix material, the mass ratio of the protective agent to the citrus peel composite material is 2:(0.5 to 1.5), for example, 2:0.5, 2:0.7, 2:1, 2:1.3, 2:1.5 or other ratios within this range; the protective agent includes glycerol and ethanol, and the volume ratio of glycerol and ethanol is 1:(1.5 to 3), for example, 1:1.5, 1:2, 1:2.5, 1:3 or other ratios within this range; the mass concentration of ethanol is 90 to 99%, for example, 90%, 93%, 95%, 97%, 99% or other values ​​within this range.

[0018] In a second aspect, the present invention provides a citrus peel biomatrix material prepared using any of the above-described preparation methods.

[0019] In some implementation schemes, the specific surface area of ​​the citrus peel biomatrix material is 600–650 m². 2 / g, total pore volume is 0.3~0.5cm³ 3 / g, with an average pore size of 4–6 nm.

[0020] In a third aspect, the present invention provides the application of the citrus peel biomatrix material described above in wastewater treatment.

[0021] The beneficial effects of this invention are as follows: Unlike existing technologies, this invention increases the pore diameter and porosity of citrus peel through acid treatment, which is beneficial for microbial colonization and also allows for better adsorption of organic matter in wastewater. Furthermore, soaking the acid-treated citrus peel in nutrient solution and coating it with photosynthetic bacteria powder results in a citrus peel bio-matrix material that can more efficiently remove organic pollutants from wastewater. Additionally, coating the surface of the citrus peel with a protective agent facilitates better colonization of photosynthetic bacteria, further enhancing the wastewater treatment capacity of this citrus peel bio-matrix material. Simultaneously, this citrus peel bio-matrix material degrades slowly. Therefore, this citrus peel bio-matrix material has promising applications in wastewater treatment. Attached Figure Description

[0022] Figure 1 This is a flowchart illustrating the preparation method of the citrus peel bio-matrix material of the present invention. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] Experimental methods not specified in the examples are generally performed under conventional conditions and as described in the manual, or as recommended by the manufacturer. Unless otherwise specified, the general equipment, materials, reagents, etc. used are commercially available.

[0025] Please see Figure 1 The flowchart illustrates the preparation method of the citrus peel biomatrix material of the present invention. Specifically, the preparation of the citrus peel biomatrix material includes the following steps: soaking citrus peel in an acidic solution, then removing it and air-drying it to obtain a citrus peel pretreated material; soaking the pretreated citrus peel in a nutrient solution to obtain a citrus peel intermediate material; coating the surface of the citrus peel intermediate material with photosynthetic bacteria powder, and then culturing it under light to obtain a citrus peel composite material; coating the surface of the citrus peel composite material with a protective agent to obtain the citrus peel biomatrix material; wherein the protective agent includes glycerol and / or ethanol.

[0026] Example 1

[0027] A method for preparing a citrus peel bio-matrix material includes the following steps:

[0028] 1) Soak citrus peels in a sulfuric acid solution with a pH of 3.5 for 2 hours, then remove them and air dry them in a cool place for 2 hours to obtain citrus peel pretreatment material;

[0029] 2) Soak the pretreated citrus peel in a nutrient solution (containing 1g NH4Cl, 3.5g CH3COONa, 0.1g MgCl2, 0.1g CaCl2, 0.6g KH2PO4, 0.4g K2HPO4, 0.1g yeast extract, 1000ml water, pH 7.2) for 3.5 hours to obtain the intermediate material of citrus peel;

[0030] 3) Coat the surface of the citrus peel intermediate material with purple sulfur fungus powder. The mass ratio of purple sulfur fungus powder to citrus peel intermediate material is 1:2. Then, under the conditions of 80% humidity, 25℃ temperature and 4000 Lux light intensity, culture for 5 days to obtain citrus peel composite material.

[0031] 4) Coat the surface of the citrus peel composite material with a mixture of glycerol and ethanol (add 10 ml of glycerol to 20 ml of 95% pure ethanol solution). The mass ratio of the glycerol and ethanol mixture to the citrus peel composite material is 2:1 to obtain the citrus peel biomatrix material.

[0032] Example 2

[0033] A method for preparing a citrus peel bio-matrix material includes the following steps:

[0034] 1) Soak citrus peels in a sulfuric acid solution with a pH of 3 for 1 hour, then remove them and air dry them in a cool place for 1 hour to obtain citrus peel pretreatment material;

[0035] 2) Soak the pretreated citrus peel in a nutrient solution (containing 1g NH4Cl, 3.5g CH3COONa, 0.1g MgCl2, 0.1g CaCl2, 0.6g KH2PO4, 0.4g K2HPO4, 0.1g yeast extract, 1000ml water, pH 7.2) for 5 hours to obtain the intermediate material of citrus peel;

[0036] 3) Coat the surface of the citrus peel intermediate material with purple sulfur-free fungal powder. The mass ratio of purple sulfur-free fungal powder to citrus peel intermediate material is 1.5:2. Then, under the conditions of 70% humidity, 20℃ temperature and 3500 Lux light intensity, cultivate for 3 days to obtain citrus peel composite material.

[0037] 4) Coat the surface of the citrus peel composite material with a mixture of glycerol and ethanol (add 10 ml of glycerol to 20 ml of 95% pure ethanol solution). The mass ratio of the glycerol and ethanol mixture to the citrus peel composite material is 2:1.5 to obtain the citrus peel biomatrix material.

[0038] Example 3

[0039] A method for preparing a citrus peel bio-matrix material includes the following steps:

[0040] 1) Soak citrus peels in a sulfuric acid solution with a pH of 4 for 3 hours, then remove them and air dry them in a cool place for 3 hours to obtain citrus peel pretreatment material;

[0041] 2) Soak the pretreated citrus peel in a nutrient solution (containing 1g NH4Cl, 3.5g CH3COONa, 0.1g MgCl2, 0.1g CaCl2, 0.6g KH2PO4, 0.4g K2HPO4, 0.1g yeast extract, 1000ml water, pH 7.2) for 2 hours to obtain the intermediate material of citrus peel;

[0042] 3) Coat the surface of the citrus peel intermediate material with green sulfur bacteria powder. The mass ratio of green sulfur bacteria powder to citrus peel intermediate material is 0.5:2. Then, under the conditions of 90% humidity, 30℃ temperature and 4500 Lux light intensity, cultivate for 7 days to obtain citrus peel composite material.

[0043] 4) Coat the surface of the citrus peel composite material with a mixture of glycerol and ethanol (add 10 ml of glycerol to 20 ml of 95% pure ethanol solution). The mass ratio of the glycerol and ethanol mixture to the citrus peel composite material is 2:0.5 to obtain the citrus peel biomatrix material.

[0044] Comparative Example 1

[0045] The preparation method of the citrus peel biomatrix material in this comparative example is basically the same as that in Example 1, except that the citrus peel is not pretreated in step 1).

[0046] Comparative Example 2

[0047] The preparation method of the citrus peel bio-matrix material in this comparative example is basically the same as that in Example 1. The difference is that the coating treatment with purple sulfur fungus powder in step 3) is not performed.

[0048] Comparative Example 3

[0049] The preparation method of the citrus peel biomatrix material in this comparative example is basically the same as that in Example 1, except that the coating treatment with a mixture of glycerol and ethanol in step 4) is not performed.

[0050] Comparative Example 4

[0051] The preparation method of the citrus peel biomatrix material in this comparative example is basically the same as that in Example 1, except that in step 4), only glycerol is coated.

[0052] Comparative Example 5

[0053] The preparation method of the citrus peel biomatrix material in this comparative example is basically the same as that in Example 1, except that in step 4), only ethanol is coated.

[0054] Performance testing

[0055] The specific surface area, total pore volume, and average pore size of the citrus peel pretreated material and the untreated citrus peel in step 1) of Example 1 were tested, and the results are shown in Table 1 below:

[0056] Table 1. Test results of specific surface area, total pore volume, and average pore size of citrus peel.

[0057]

[0058] As can be seen from the data in Table 1, the specific surface area, total pore volume, and average pore size of citrus peel all increased significantly after acid treatment.

[0059] Application testing

[0060] Organic pollutant indicators in low C / N ratio domestic wastewater (C / N ratio 6:1) were analyzed and tested, and the measured concentrations were: COD 262.4 mg / L, TN 38.7 mg / L, and TP 5.75 mg / L. 1 L of each of the above low C / N ratio domestic wastewater samples was added to eight reactors respectively.

[0061] The citrus peel bio-matrix materials prepared in Examples 1-3 and Comparative Examples 1-5 were added to the eight reactors mentioned above, with an addition amount of 5.0 g for each. The pH of the solution was adjusted to 7.2, and the reactors were placed in a natural environment at 27°C for 12 h. Samples were taken at 3, 6, 9, and 12 h to detect the concentration of organic pollutants. The results are shown in Table 2 below:

[0062] Table 2. Removal results of organic pollutants by citrus peel bio-matrix material

[0063]

[0064]

[0065]

[0066] As can be seen from the data in Table 2, the citrus peel biomatrix materials prepared in Examples 1-3 have a better removal effect on organic matter (COD, TN, TP) in wastewater.

[0067] In Comparative Example 1, the citrus peels were not pretreated. The results showed that the removal rate of organic matter by the citrus peel bio-matrix material decreased to some extent. The results indicate that the pore diameter and porosity of the citrus peels increased after pretreatment, which enabled them to better adsorb organic matter in the wastewater.

[0068] In Comparative Example 2, the surface of the citrus peel bio-matrix material was not coated with sulfur fungus powder. The results showed that the removal rate of organic matter by the citrus peel bio-matrix material was significantly reduced. The results indicate that after coating with sulfur fungus powder, the sulfur fungus powder and citrus peel worked synergistically to further improve the adsorption of organic matter in wastewater.

[0069] In Comparative Examples 3-5, the surface of the citrus peel biomatrix material was either not coated with a mixture of glycerol and ethanol, or coated with only one of glycerol and ethanol. The results showed that the removal rate of organic matter by the citrus peel biomatrix material decreased to some extent. The results indicate that coating the citrus peel biomatrix material with a mixture of glycerol and ethanol can further enhance the adsorption of organic matter in wastewater, and there is a synergistic effect between glycerol and ethanol. The adsorption performance of the citrus peel biomatrix material is better when coated with both glycerol and ethanol.

[0070] It should be noted that all the above embodiments belong to the same inventive concept, and the descriptions of each embodiment have different focuses. Where the description in a particular embodiment is not detailed, please refer to the description in other embodiments.

[0071] The embodiments described above are merely illustrative of implementation methods of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. The application of a citrus peel bio-matrix material in wastewater treatment, characterized in that, The preparation method of the citrus peel bio-matrix material includes the following steps: The citrus peels are soaked in an acidic solution, then removed and air-dried to obtain citrus peel pre-treated material. The citrus peel pretreatment material is soaked in a nutrient solution to obtain citrus peel intermediate material; Photosynthetic bacteria powder is coated onto the surface of the citrus peel intermediate material, and then cultured under light to obtain a citrus peel composite material. A protective agent is coated onto the surface of the citrus peel composite material to obtain a citrus peel biomatrix material. The pH value of the acid solution is 3-4; The mass ratio of the protective agent to the citrus peel composite material is 2:(0.5~1.5); the protective agent includes glycerol and ethanol, and the volume ratio of the glycerol and the ethanol is 1:(1.5~3), and the mass concentration of the ethanol is 90~99%.

2. The application according to claim 1, characterized in that, In the preparation of the citrus peel pretreatment material, the acid solution is selected from at least one of sulfuric acid solution, nitric acid solution and hydrochloric acid solution.

3. The application according to claim 1, characterized in that, In the preparation process of the citrus peel pretreatment material, the soaking includes a soaking time of 1 to 3 hours.

4. The application according to claim 1, characterized in that, In the preparation of the intermediate material of citrus peel, the nutrient solution includes: 0.8~1.2g NH4Cl, 3~4g CH3COONa, 0.05~0.15g MgCl2, 0.05~0.15g CaCl2, 0.5~0.7g KH2PO4, 0.3~0.5g K2HPO4, 0.05~0.15g yeast extract, 800~1200ml water, and a pH value of 7~7.

4.

5. The application according to claim 1, characterized in that, In the preparation process of the citrus peel intermediate material, the soaking includes a soaking time of 2-5 hours.

6. The application according to claim 1, characterized in that, In the preparation process of the citrus peel composite material, the mass ratio of the photosynthetic bacteria powder to the citrus peel intermediate material is (0.5~1.5):2; and the photosynthetic bacteria are selected from at least one of purple sulfur bacteria, purple sulfur-free bacteria, green sulfur bacteria, and green sulfur-free bacteria.

7. The application according to claim 1, characterized in that, In the preparation process of the citrus peel composite material, the light cultivation includes: cultivating for 3 to 7 days under the conditions of humidity of 70 to 90%, temperature of 20 to 30°C, and light intensity of 3500 to 4500 Lux.

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