An environmentally friendly treatment method for baicalic acid precipitate

Abstract

This invention discloses an environmentally friendly treatment method for baicalein effluent, comprising the following steps: pumping the baicalein effluent into a macroporous resin column for adsorption, using purified water as top feed, and combining the effluent and top feed liquid as the first effluent; using an alcohol solution to desorb the macroporous resin column, collecting the second effluent, concentrating and drying the second effluent to obtain baicalein flavonoids; adding quicklime to the first effluent to adjust its pH to 7-8, then stirring and reacting, followed by filtration, drying and pulverizing the filter cake to obtain tricalcium phosphate product; concentrating the filtrate through a nanofiltration membrane, using the membrane permeate for the next batch of baicalein powder extraction, and spray-drying the membrane concentrate to obtain baicalein polysaccharides. The method provided by this invention recycles baicalein effluent to produce high-value-added baicalein flavonoids, baicalein polysaccharides, and tricalcium phosphate as byproducts, and the entire process generates no polluting wastewater. Tricalcium phosphate contains abundant phosphorus and organic calcium salts, and can be used as biomass organic fertilizer.

Description

Technical Field

[0001] This invention relates to the field of plant extraction technology, specifically to an environmentally friendly method for treating baicalein precipitate. Background Technology

[0002] Scutellaria baicalensis is one of the most commonly used Chinese herbs in clinical practice and in prepared Chinese medicine. With the advancement of science and technology and people's increasing focus on health, the utilization of Chinese medicine is receiving more and more attention. Currently, in the process of producing baicalin from Scutellaria baicalensis, most pharmaceutical factories directly discard large amounts of baicalein precipitate, causing environmental pollution.

[0003] Currently, hydrochloric acid solution is commonly used for acid precipitation in the production of baicalin, resulting in a high concentration of chloride ions in the baicalic acid precipitate. Direct discharge of this precipitate as wastewater can corrode metallic substances in water bodies, particularly sewers, pipes, and equipment, leading to facility damage and increased maintenance costs. Furthermore, hydrochloric acid's high solubility in water means that discharged wastewater may alter the pH of water bodies, impairing their self-purification capacity and affecting the growth and reproduction of aquatic organisms. Hydrochloric acid gas can also cause respiratory irritation and eye damage. Therefore, recycling and reusing the baicalic acid precipitate not only solves the environmental pollution problem but also enhances its economic value. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide an environmentally friendly treatment method for baicalein effluent, which addresses the shortcomings of existing technologies. This method recycles baicalein effluent to produce high-value-added baicalein flavonoids, baicalein polysaccharides, and tricalcium phosphate as byproducts. The entire process produces no polluting wastewater discharge. The baicalein flavonoids are naturally extracted antibiotic alternatives, baicalein polysaccharides have antioxidant and immune-enhancing functions, and tricalcium phosphate contains abundant phosphorus and organic calcium salts, which can be used as biomass organic fertilizer.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0006] An environmentally friendly method for treating baicalein precipitate includes the following steps:

[0007] (1) The scutellaria baicalensis acid precipitate was pumped into a macroporous resin column for adsorption, and then purified water was used as the top feed. The effluent from the adsorption process and the top feed liquid from the top feed process were combined as the first effluent.

[0008] (2) The macroporous resin column was treated with an alcohol solution as an eluent, the second effluent was collected, and the second effluent was concentrated and dried to obtain Scutellaria baicalensis flavonoids.

[0009] (3) Add quicklime to the first effluent to adjust its pH to 7-8, then stir and react, then filter, dry the filter cake and crush it to obtain tricalcium phosphate product; filter the filtrate with a 200-400 Da nanofiltration membrane, use the nanofiltration membrane permeate as the extraction solvent for the next batch of Scutellaria baicalensis powder, and spray dry the nanofiltration membrane retentate to obtain Scutellaria baicalensis polysaccharide.

[0010] As a preferred embodiment of the above technical solution, in step (1), the Scutellaria baicalensis acid precipitation solution is obtained by acid precipitation treatment of the extract of Scutellaria baicalensis root with phosphoric acid.

[0011] As a preferred embodiment of the above technical solution, in step (1), the extract of Scutellaria baicalensis root is obtained by adding the crushed Scutellaria baicalensis root to boiling water for extraction.

[0012] As a preferred embodiment of the above technical solution, in step (1), the mass ratio of solid to liquid during extraction is 1:(5-10), and the extraction time is 1-2 hours.

[0013] As a preferred embodiment of the above technical solution, in step (1), the preparation process of the baicalein precipitate is as follows: the pH of the extract of Scutellaria baicalensis root is adjusted to 1.5-2.5 with phosphoric acid, and the extract is kept at a temperature above 90°C until no new precipitate is produced. The extract is then filtered and the filtrate is collected.

[0014] As a preferred embodiment of the above technical solution, in step (1), the feed rate of baicalein precipitate and the feed rate of purified water are both 0.5-4 BV / h; the volume of baicalein precipitate is 20-30 BV of resin volume, and the volume of purified water is 0.5-2 BV of resin volume.

[0015] As a preferred embodiment of the above technical solution, in step (1), the adsorption temperature is 40-80℃.

[0016] As a preferred embodiment of the above technical solution, in step (2), the alcohol solution is an ethanol solution or a methanol solution with a concentration of 60-80 v / v%.

[0017] As a preferred embodiment of the above technical solution, in step (2), the volume of the alcohol solution during the analysis process is 2-4 BV of the resin volume, and the feed rate of the alcohol solution is 0.5-2 BV / h.

[0018] As a preferred embodiment of the above technical solution, in step (3), the temperature of the stirring reaction is 30-60℃, and the stirring reaction time is not less than 0.5h after the pH of the solution has no change.

[0019] As a preferred embodiment of the above technical solution, in step (3), the solid content of the nanofiltration membrane retentate is 20-55 wt%.

[0020] Due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0021] This invention involves sequentially adsorbing and desorbing the scutellaria baicalensis acid precipitate with macroporous resin, reacting it with quicklime, and filtering it with a nanofiltration membrane to obtain high-value-added scutellaria baicalensis flavonoids, scutellaria baicalensis polysaccharides, and tricalcium phosphate. The entire process is simple to operate and suitable for large-scale production; moreover, no polluting wastewater is discharged during the production process, making it more economical and environmentally friendly.

[0022] This invention uses phosphoric acid instead of hydrochloric acid to perform acid precipitation of Scutellaria baicalensis extract, which not only ensures high yield and high purity of baicalin, but also eliminates chloride ions in the collected Scutellaria baicalensis acid precipitation solution, thus extending the service life of the equipment.

[0023] This invention, through effective adjustment of process conditions, produces scutellaria baicalensis flavonoids, scutellaria baicalensis polysaccharides, and tricalcium phosphate with high purity and high yield. The byproducts, scutellaria baicalensis flavonoids, are naturally extracted antibiotic alternatives; scutellaria baicalensis polysaccharides possess antioxidant and immune-enhancing functions and can be used as functional feed additives; and tricalcium phosphate provides essential phosphorus for plant growth and contains a large amount of organic calcium salts, thus possessing considerable economic value. Detailed Implementation

[0024] The present invention is further illustrated below with reference to embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0025] Example 1

[0026] Preparation of baicalin:

[0027] S1: Add 2 kg of Scutellaria baicalensis powder obtained by crushing Scutellaria baicalensis root to 20 L of boiling water for 1 hour, filter, and collect the first filtrate and the first residue; add the first residue to 12 L of boiling water for 1 hour, filter, and collect the second filtrate and the second residue; add the second residue to 10 L of boiling water for 1 hour, filter, and collect the third filtrate; combine the first filtrate, the second filtrate and the third filtrate to obtain Scutellaria baicalensis extract;

[0028] S2: Add a 20wt% phosphoric acid solution to the Scutellaria baicalensis extract to adjust its pH to 1.5. Keep it at 95℃ until no new precipitate is formed. Filter and collect the filtrate to obtain baicalein. Dry and pulverize the filter residue to obtain baicalin.

[0029] Example 2

[0030] Preparation of baicalin:

[0031] S1: Add 2 kg of Scutellaria baicalensis powder obtained by crushing Scutellaria baicalensis root to 20 L of boiling water for 1 hour, filter, and collect the first filtrate and the first residue; add the first residue to 12 L of boiling water for 1 hour, filter, and collect the second filtrate and the second residue; add the second residue to 10 L of boiling water for 1 hour, filter, and collect the third filtrate; combine the first filtrate, the second filtrate and the third filtrate to obtain Scutellaria baicalensis extract;

[0032] S2: Add a 20wt% phosphoric acid solution to the Scutellaria baicalensis extract to adjust its pH to 2.5. Keep it at 95℃ until no new precipitate is formed. Filter and collect the filtrate to obtain baicalein. Dry and pulverize the filter residue to obtain baicalin.

[0033] Example 3

[0034] Preparation of Scutellaria baicalensis flavonoids:

[0035] A: Using the baicalein precipitate obtained in Example 1 as raw material, 25 BV of baicalein precipitate was pumped into a macroporous resin column at a flow rate of 1 BV / h and adsorbed at 60°C. Then, 1 BV of purified water was used as the top feed at a flow rate of 1 BV / h. The effluent from the adsorption process and the top feed liquid from the top feed process were combined as the first effluent.

[0036] B: An ethanol solution with a concentration of 70 v / v% and a resin volume of 3 BV was pumped into a macroporous resin column at a flow rate of 1 BV / h for desorption treatment. The second effluent was collected, concentrated, and dried to obtain scutellaria baicalensis flavonoids.

[0037] Example 4

[0038] Preparation of Scutellaria baicalensis flavonoids:

[0039] A: Using the baicalein precipitate obtained in Example 1 as raw material, 25 BV of baicalein precipitate was pumped into a macroporous resin column at a flow rate of 4 BV / h and adsorbed at 60°C. Then, 1 BV of purified water was used as the top feed at a flow rate of 4 BV / h. The effluent from the adsorption process and the top feed liquid from the top feed process were combined as the first effluent.

[0040] B: An ethanol solution with a concentration of 70 v / v% and a resin volume of 3 BV was pumped into a macroporous resin column at a flow rate of 1 BV / h for analysis. The second effluent was collected, concentrated, and dried to obtain scutellaria baicalensis flavonoids.

[0041] Example 5

[0042] Preparation of tricalcium phosphate and Scutellaria baicalensis polysaccharide:

[0043] (1) Using the first effluent obtained in Example 3 as raw material, quicklime was added to the first effluent at a temperature of 40°C to adjust its pH to 8. After stirring until there was no pH change in the liquid, stirring was continued for 0.5 hours. The liquid was filtered, the filtered clear liquid was collected, the filter cake was dried and crushed to obtain tricalcium phosphate product.

[0044] (2) The filtered liquid is concentrated using a 200Da nanofiltration membrane, the liquid-solid content is controlled to be 30wt%, and spray-dried to obtain Scutellaria baicalensis polysaccharide product; the liquid is then used in the extraction process of the next batch of Scutellaria baicalensis powder.

[0045] Example 6

[0046] Preparation of tricalcium phosphate and Scutellaria baicalensis polysaccharide:

[0047] (1) Using the first effluent obtained in Example 3 as raw material, quicklime was added to the first effluent at a temperature of 40°C to adjust its pH to 7. After stirring until there was no pH change in the liquid, stirring was continued for 0.5 hours. The liquid was filtered, the filtered clear liquid was collected, the filter cake was dried and crushed to obtain tricalcium phosphate product.

[0048] (2) The filtered liquid is concentrated using a 400Da nanofiltration membrane, and the liquid-solid content is controlled to be 50wt%. The product is spray-dried to obtain Scutellaria baicalensis polysaccharide. The liquid is then used in the next batch of feed.

[0049] Comparative Example 1

[0050] Add a 20wt% phosphate solution to the Scutellaria baicalensis extract to adjust its pH to 4, and keep other conditions the same as in Example 1.

[0051] Comparative Example 2

[0052] Add a 20wt% phosphate solution to the Scutellaria baicalensis extract to adjust its pH to 1, and other conditions are the same as in Example 1.

[0053] Comparative Example 3

[0054] The feed rate of the baicalein precipitate and the feed rate of the purified water were set to 6 BV / h, and other conditions were the same as in Example 3.

[0055] Comparative Example 4

[0056] At a temperature of 40°C, quicklime was added to the first effluent to adjust its pH to 5, and other conditions were the same as in Example 5.

[0057] Comparative Example 5

[0058] At a temperature of 40°C, quicklime was added to the first effluent to adjust its pH to 11, and other conditions were the same as in Example 5.

[0059] In the above embodiments and comparative examples, baicalin, baicalein flavonoids, baicalein polysaccharide and tricalcium phosphate were prepared. The purity and yield of the products were tested, and the test methods are as follows. The test results are shown in Table 1.

[0060] The yield (%) of baicalin = [(weight of target product * purity of baicalin in target product) / (weight of solids in Scutellaria baicalensis extract * purity of baicalin in solids of Scutellaria baicalensis extract)] × 100%;

[0061] Baicalein yield (%) = [(Target product weight * Purity of baicalein in the target product) / (Solid weight in baicalein precipitate * Purity of baicalein in the solid in baicalein precipitate)] × 100%;

[0062] Scutellaria baicalensis polysaccharide yield (%) = [(target product weight * purity of scutellaria baicalensis polysaccharide in the target product) / (weight of solids in scutellaria baicalensis acid precipitate * purity of scutellaria baicalensis polysaccharide in the solids of scutellaria baicalensis acid precipitate)] × 100%;

[0063] Tricalcium phosphate yield (%) = [(Target product weight * Tricalcium phosphate purity in the target product) / (Solid weight of the feed liquid when the pH of the first effluent remains unchanged after adjustment with quicklime * Tricalcium phosphate purity in the solids of the feed liquid when the pH of the first effluent remains unchanged after adjustment with quicklime)] × 100%.

[0064] Table 1

[0065]

[0066]

[0067] In the above test results, the baicalin, baicalein flavonoids, baicalein polysaccharides, and tricalcium phosphate prepared in the embodiments of the present invention showed high yields and purity. Compared with Comparative Example 1 and Example 1, the purity of baicalin did not change significantly, but the yield decreased greatly. This was mainly because the pH was too high during acid precipitation, preventing baicalin from completely precipitating from the extract, thus affecting its yield. Compared with Comparative Example 2 and Example 1, the yield of baicalin was not affected, but the purity was very low. This was mainly because the pH was too low, causing other impurities to precipitate from the extract, thus affecting the purity of baicalin. To ensure high purity and high yield of baicalin, the present invention controls the pH during acid precipitation to be 1.5-2.5.

[0068] Compared with Comparative Example 3 and Example 3, the purity of baicalein did not decrease significantly, but the yield was greatly reduced. This is mainly because, during the adsorption process, an excessively fast feed rate of the baicalein precipitate can lead to a false saturation of the resin adsorption, thus affecting the adsorption of baicalein and consequently reducing its yield. To ensure high purity and high yield of baicalein, this invention controls the feed rate of the baicalein precipitate to 0.5-4 BV / h.

[0069] Compared to Comparative Example 4 and Example 5, the yield of tricalcium phosphate was significantly reduced, and the purity of Scutellaria baicalensis polysaccharide was significantly reduced. This was mainly because, at low pH, the reaction between quicklime and the first effluent was incomplete, thus affecting the yield of tricalcium phosphate; furthermore, the filtrate contained more impurities, affecting the purity of Scutellaria baicalensis polysaccharide. Compared to Comparative Example 5 and Example 5, the purity of tricalcium phosphate was significantly reduced, and both the purity and yield of Scutellaria baicalensis polysaccharide were significantly reduced. This was mainly because at excessively high pH, ​​the amount of quicklime required would increase, and excess quicklime would react with water to form calcium hydroxide precipitate. Additionally, other impurities in the first effluent would also precipitate, affecting the purity of tricalcium phosphate. Furthermore, a large amount of quicklime would destroy the effective components in the first effluent, thus affecting the purity and yield of Scutellaria baicalensis polysaccharide. Therefore, to ensure high purity and high yield of both tricalcium phosphate and Scutellaria baicalensis polysaccharide, this invention controls the pH of the first effluent to 7-8.

[0070] Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to this invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. An environmentally friendly method for treating baicalein precipitate, characterized in that, Includes the following steps: (1) The baicalein precipitate is pumped into a macroporous resin column for adsorption, and then purified water is used as the top feed. The effluent from the adsorption process and the top feed liquid from the top feed process are combined as the first effluent. The feed rate of the baicalein precipitate and the feed rate of the purified water are both 0.5-4 BV / h. The volume of the baicalein precipitate is 20-30 BV of the resin volume, and the volume of the purified water is 0.5-2 BV of the resin volume. (2) The macroporous resin column was treated with an alcohol solution as an eluent, the second effluent was collected, and the second effluent was concentrated and dried to obtain Scutellaria baicalensis flavonoids. (3) Add quicklime to the first effluent to adjust its pH to 7-8, then stir and react. After the filter cake is dried, it is crushed to obtain tricalcium phosphate product. The filtrate is filtered through a 200-400 Da nanofiltration membrane. The membrane permeate is used as the extraction solvent for the next batch of Scutellaria baicalensis powder. The membrane concentrate is spray-dried to obtain Scutellaria baicalensis polysaccharide.

2. The environmentally friendly treatment method for baicalein precipitate according to claim 1, characterized in that, In step (1), the Scutellaria baicalensis acid precipitation solution is obtained by acid precipitation treatment of the extract of Scutellaria baicalensis root with phosphoric acid.

3. The environmentally friendly treatment method for baicalein precipitate according to claim 2, characterized in that, In step (1), the extract of Scutellaria baicalensis root is obtained by adding the crushed Scutellaria baicalensis root to boiling water for extraction.

4. The environmentally friendly treatment method for baicalein precipitate according to claim 3, characterized in that, In step (1), the mass ratio of solid to liquid during extraction is 1:(5-10), and the extraction time is 1-2 hours.

5. The environmentally friendly treatment method for baicalein precipitate according to claim 1, characterized in that, In step (1), the preparation process of baicalein precipitate is as follows: the pH of the extract of Scutellaria baicalensis root is adjusted to 1.5-2.5 with phosphoric acid, and the extract is kept at a temperature above 90°C until no new precipitate is produced. The extract is then filtered and the filtrate is collected.

6. The environmentally friendly treatment method for baicalein precipitate according to claim 1, characterized in that, In step (1), the adsorption temperature is 40-80℃.

7. The environmentally friendly treatment method for baicalein precipitate according to claim 1, characterized in that, In step (2), the alcohol solution is an ethanol solution or a methanol solution with a concentration of 60-80 v / v%.

8. The environmentally friendly treatment method for baicalein precipitate according to claim 1, characterized in that, In step (2), the volume of the alcohol solution during the analytical treatment is 2-4 BV of the resin volume, and the feed rate of the alcohol solution is 0.5-2 BV / h.

9. The environmentally friendly treatment method for baicalein precipitate according to claim 1, characterized in that, In step (3), the temperature of the stirring reaction is 30-60℃, and the stirring reaction time is not less than 0.5h.

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