Liquid membrane for wastewater treatment and method for its preparation

Abstract

The application discloses a liquid membrane for sewage treatment and a preparation method thereof. The liquid membrane comprises a emulsion formed by mixing vegetable oil, a surfactant, Gleditsia sinensis saponin and an aqueous inorganic acid solution. The preparation method of the emulsion membrane comprises the following steps: mixing the vegetable oil, the surfactant, the Gleditsia sinensis saponin and the aqueous inorganic acid solution according to proper proportions, and fully stirring to obtain stable emulsion. The emulsion membrane can be applied to treatment of sewage containing ephedrine. The application can efficiently recover and extract ephedrine from pharmaceutical wastewater, reduce the ephedrine content in the pharmaceutical wastewater, reduce the influence of ephedrine on the environment, improve the raw material utilization rate of ephedrine, and the recovery efficiency of ephedrine can reach more than 80%. The extraction and recovery steps of ephedrine are simple, time-consuming is short, and the application has a good industrial application prospect.

Description

A liquid membrane for wastewater treatment and its preparation method Technical Field

[0001] This invention relates to a liquid membrane and its preparation method, and more particularly to a liquid membrane for treating ephedrine-containing wastewater and its preparation method. Background Technology

[0002] Unreacted ephedrine is inevitably present in the synthesis of ephedrine and its derivatives, as well as in pharmaceutical wastewater. Once this wastewater enters the environment, it can cause toxic effects on aquatic organisms and allergic reactions and other adverse effects in humans, leading to chronic health problems. Furthermore, as a precursor to controlled substances, the procurement and use of ephedrine are strictly controlled, and excessively high levels of ephedrine in wastewater can also lead to the risk of illegal recycling and extraction for drug production.

[0003] To reduce the environmental impact of ephedrine, physical, chemical, and biological methods are commonly used to treat pharmaceutical wastewater containing ephedrine. These methods primarily include activated carbon adsorption, advanced oxidation processes (such as ozone oxidation and Fenton reaction), and specific microbial community decomposition methods. While these methods can reduce the ephedrine content in pharmaceutical wastewater, they are not effective at recovering ephedrine, or the recovery process is complex, inefficient, and costly. To improve the utilization rate of ephedrine, reduce raw material waste, and mitigate the risk of ephedrine leakage as a precursor chemical, a rapid method for recovering ephedrine from pharmaceutical wastewater is urgently needed. Currently, there are no reported cases of using liquid membrane methods to recover ephedrine.

[0004] Gleditsioside monomers are triterpenoid saponin compounds isolated from the legume *Gleditsia sinensis* and its closely related species. Their structures are based on oleanolic acid or sennanic acid as aglycones, combined with different sugar chains (glucose, arabinose, xylose, rhamnose, and galacturonic acid, etc.). Currently identified major monomers include Gleditsiosides AG, Gleditsiosides N, Gleditsiosides O, Gleditsiosides P, Gleditsiosides Q, and Gleditsiosides HK, among others. An extended series of monomers found in *Gleditsioside* fruits exhibits differences in sugar chain length and monosaccharide arrangement; some monomers possess stronger surface activity and antitumor potential. Summary of the Invention

[0005] Objective of this invention: The objective of this invention is to provide an emulsion membrane capable of rapidly and efficiently recovering ephedrine from pharmaceutical wastewater. A second objective is to propose a method for preparing the aforementioned emulsion membrane, thus addressing the problem of how to prepare such a membrane. A third objective is to propose an application of the aforementioned emulsion membrane in treating ephedrine-containing wastewater, thereby solving the problem of how to recover and extract ephedrine from such wastewater.

[0006] Technical solution: The liquid membrane for wastewater treatment described in this invention is characterized by comprising an emulsion formed by mixing vegetable oil, surfactant, saponins, and an aqueous solution of inorganic acid.

[0007] This invention uses saponins from saponins as a key auxiliary agent, which effectively improves the recovery and extraction efficiency of ephedrine from emulsion membranes and solves the problem that existing emulsion membrane systems are unable to recover and extract ephedrine from ephedrine-containing wastewater.

[0008] Preferably, the saponins contain at least one of the following monomers: saponins A, B, C, D, E, F, G, H, I, J, K, N, O, P, and Q.

[0009] Preferably, the saponins are composed of at least two of saponin A, B, and C monomers.

[0010] Preferably, the vegetable oil is selected from at least one of soybean oil, rapeseed oil, olive oil, sunflower seed oil, corn oil, sesame oil, cottonseed oil, peanut oil, and palm oil; the surfactant is selected from at least one of Span-80, Span-20, Span-40, Span-60, Tween-80, AEO-9, and OPE-10; and the inorganic acid is selected from at least one of hydrochloric acid, sulfuric acid, and phosphoric acid.

[0011] Preferably, the inorganic acid aqueous solution is a hydrochloric acid aqueous solution or a phosphoric acid aqueous solution with a concentration of 0.3-0.8M.

[0012] Preferably, the ratio of the vegetable oil, surfactant, inorganic acid aqueous solution and saponin is 20-40mL: 2-4mL: 50-100mL: 0.5-10g.

[0013] The second aspect of the present invention discloses a method for preparing the above-mentioned liquid film for wastewater treatment, comprising the following steps: mixing vegetable oil, surfactant, saponins, and an aqueous solution of inorganic acid in appropriate proportions and stirring thoroughly to obtain a stable emulsion.

[0014] Preferably, the stirring conditions are: stirring at room temperature and 1000-3000 rpm for at least 15 minutes.

[0015] The third aspect of this invention discloses the application of the above-mentioned liquid membrane in the treatment of ephedrine-containing wastewater.

[0016] The application of the above-mentioned liquid membrane treatment for ephedrine-containing wastewater includes the following steps:

[0017] (1) Adjust the pH of the ephedrine-containing wastewater to 3-6;

[0018] (2) Add the above emulsion to the ephedrine-containing wastewater at a volume ratio of 1:1-10, and continuously stir the mixture to carry out the ephedrine extraction operation.

[0019] (3) The extracted mixture was allowed to stand and separate into layers. The emulsion layer was heated to break the emulsion and the oil layer was removed to obtain an aqueous phase containing ephedrine.

[0020] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0021] This invention enables the efficient recovery and extraction of ephedrine from pharmaceutical wastewater, reducing the ephedrine content in the wastewater, mitigating the environmental impact of ephedrine, and improving the raw material utilization rate of ephedrine. The recovery efficiency of ephedrine can reach over 80%. The extraction and recovery process of ephedrine using this invention is simple, time-saving, and has good prospects for industrial application. Detailed Implementation

[0022] The technical solution of the present invention will be further described below.

[0023] Example 1: The composition ratio and preparation method of an emulsion film are as follows:

[0024] A stable emulsion was obtained by mixing 30 mL of cottonseed oil, 3 mL of Span-80, 70 mL of 0.5 M hydrochloric acid aqueous solution, and 4 g of saponins, and stirring at 2000 rpm for 30 min at room temperature. The saponins were a 1:1 weight mixture of saponins A and B.

[0025] The above-mentioned liquid membrane treatment of ephedrine-containing wastewater includes the following steps:

[0026] (1) Ephedrine was dissolved in deionized water to obtain an ephedrine aqueous solution with a concentration of 10 mg / L to simulate a wastewater sample containing ephedrine. The pH of the wastewater containing ephedrine was adjusted to 3 using hydrochloric acid.

[0027] (2) Add the above emulsion to the ephedrine-containing wastewater at a volume ratio of 1:4, and stir the mixture continuously at 200 rpm for 30 min to carry out ephedrine extraction.

[0028] (3) The extracted mixture was allowed to stand and separate into layers. The emulsion layer was heated until it broke the emulsion and the oil layer was removed to obtain an aqueous phase containing ephedrine.

[0029] Example 2: The composition ratio and preparation method of an emulsion film are as follows:

[0030] A stable emulsion was obtained by mixing 20 mL of corn oil, 4 mL of Span-80, 50 mL of 0.3 M hydrochloric acid aqueous solution, and 0.5 g of saponins, and stirring at 1000 rpm for 45 min at room temperature. The saponins were a mixture of saponins A, B, and C in a weight ratio of 1:2:1.

[0031] The above-mentioned liquid membrane treatment of ephedrine-containing wastewater includes the following steps:

[0032] (1) Ephedrine was dissolved in deionized water to obtain an ephedrine aqueous solution with a concentration of 10 mg / L to simulate a wastewater sample containing ephedrine. The pH of the wastewater containing ephedrine was adjusted to 6 using hydrochloric acid.

[0033] (2) Add the above emulsion to the ephedrine-containing wastewater at a volume ratio of 1:1, and stir the mixture continuously at 300 rpm for 20 min to carry out the ephedrine extraction operation.

[0034] (3) The extracted mixture was allowed to stand and separate into layers. The emulsion layer was heated until it broke the emulsion and the oil layer was removed to obtain an aqueous phase containing ephedrine.

[0035] Example 3: The composition ratio and preparation method of an emulsion film are as follows:

[0036] A stable emulsion was obtained by mixing 40 mL of palm oil, 2 mL of Span-80, 100 mL of 0.8 M phosphoric acid aqueous solution, and 10 g of saponins, and stirring at 3000 rpm for 15 min at room temperature. The saponins were a mixture of saponins B and C in a weight ratio of 1:3.

[0037] The above-mentioned liquid membrane treatment of ephedrine-containing wastewater includes the following steps:

[0038] (1) Ephedrine was dissolved in deionized water to obtain an ephedrine aqueous solution with a concentration of 10 mg / L to simulate a wastewater sample containing ephedrine. The pH of the wastewater containing ephedrine was adjusted to 5 using phosphoric acid.

[0039] (2) Add the above emulsion to the ephedrine-containing wastewater at a volume ratio of 1:10, and stir the mixture continuously at 200 rpm for 15 min to carry out ephedrine extraction.

[0040] (3) The extracted mixture was allowed to stand and separate into layers. The emulsion layer was heated until it broke the emulsion and the oil layer was removed to obtain an aqueous phase containing ephedrine.

[0041] Example 4: Everything else is the same as in Example 1, except that:

[0042] An aqueous solution of ephedrine with a concentration of 100 mg / L was used to simulate wastewater samples containing ephedrine.

[0043] Comparative Example 1: Everything else is the same as in Example 1, except that:

[0044] Saponins are only one of the monomers of saponins A, B, C, D, E, F, G, H, I, J, K, N, O, P, and Q.

[0045] Comparative Example 2: Everything else is the same as in Example 1, except that:

[0046] Replace Span-80 with one of Span-40, Tween-80, or AEO-9.

[0047] Comparative Example 3: Everything else is the same as in Example 1, except that:

[0048] No saponins are added.

[0049] Comparative Example 4: Everything else is the same as in Example 1, except that:

[0050] Saponin D was used to replace saponin A.

[0051] Comparative Example 5: Everything else is the same as in Example 1, except that:

[0052] Saponin G was used to replace saponin B.

[0053] The concentration of ephedrine in the aqueous phases containing ephedrine prepared in Examples 1-4 and Comparative Examples 1-5 was determined by high performance liquid chromatography (HPLC), and the recovery rate was calculated using the following formula:

[0054] Recovery rate = (HPLC concentration × total volume of aqueous phase containing ephedrine) / (total weight of ephedrine in wastewater sample containing ephedrine) × 100%;

[0055] The test results are as follows:

[0056] Table 1 Recovery rates of ephedrine using different emulsion membranes

[0057]

[0058]

[0059] Table 1 shows that Comparative Example 1 indicates that the recovery rate of ephedrine in the liquid membrane system is low when using saponin monomers alone. Combined with Comparative Examples 4 and 5, it is evident that a high ephedrine recovery rate can only be achieved when specific types of saponin monomers are used in combination. Comparative Example 3 shows that the existing liquid membrane system has low ephedrine recovery efficiency. Combined with Comparative Example 1, it is evident that the addition of certain types of saponin monomers actually reduces the ephedrine recovery rate of the existing liquid membrane system and is not suitable for the separation and extraction of ephedrine. Examples 1-4 show that the combined use of saponins A, B, and C can synergistically improve the recovery and separation performance of the liquid membrane system for ephedrine. Combined with Comparative Example 2, it is evident that the improved recovery performance of saponins A and B in the liquid membrane system depends on certain types of surfactants and is not applicable to any surfactant.

Claims

1. A liquid membrane for recovering ephedrine from wastewater, characterized in that, The mixture comprises an emulsion formed by mixing vegetable oil, surfactant, saponins, and an aqueous solution of inorganic acid; wherein the saponins are a mixture of saponins A and B in a weight ratio of 1:1, a mixture of saponins A, B, and C in a weight ratio of 1:2:1, or a mixture of saponins B and C in a weight ratio of 1:3; and the surfactant is Span-80.

2. The liquid membrane for recovering ephedrine from wastewater according to claim 1, characterized in that, The vegetable oil is selected from at least one of soybean oil, rapeseed oil, olive oil, sunflower seed oil, corn oil, sesame oil, cottonseed oil, peanut oil, and palm oil, and the inorganic acid is selected from at least one of hydrochloric acid, sulfuric acid, and phosphoric acid.

3. The liquid membrane for recovering ephedrine from wastewater according to claim 1, characterized in that, The inorganic acid aqueous solution is a hydrochloric acid aqueous solution or a phosphoric acid aqueous solution with a concentration of 0.3-0.8M.

4. The liquid membrane for recovering ephedrine from wastewater according to claim 1, characterized in that, The ratio of the vegetable oil, surfactant, inorganic acid aqueous solution, and saponins is 20-40 mL: 2-4 mL: 50-100 mL: 0.5-10 g.

5. The method for preparing a liquid film for recovering ephedrine from wastewater according to any one of claims 1-4, characterized in that, The process includes the following steps: mixing vegetable oil, surfactant, saponins, and an aqueous solution of inorganic acid in appropriate proportions and stirring thoroughly to obtain a stable emulsion.

6. The method for preparing a liquid film for recovering ephedrine from wastewater according to claim 5, characterized in that, The stirring conditions are: stirring at room temperature at 1000-3000 rpm for at least 15 minutes.

7. The application of the liquid membrane according to any one of claims 1-4 in the treatment of ephedrine-containing wastewater.

8. The application according to claim 7, characterized in that, The process includes the following steps: (1) adjusting the pH of the ephedrine-containing wastewater to 3-6; (2) adding the emulsion described in claims 1-6 to the ephedrine-containing wastewater at a volume ratio of 1:1-10, and continuously stirring the mixture to extract ephedrine; (3) allowing the extracted mixture to stand and separate into layers, taking the emulsion layer, heating to break the emulsion, and removing the oil layer to obtain an aqueous phase containing ephedrine.

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