Application of thymol-based hydrophobic deep-eutectic solvent in extraction of malachite green

Abstract

The invention relates to the field of eutecticevaporate solvents, in particular to application of a thymol-based hydrophobic eutecticevaporate solvent in extraction of malachite green. The method comprises the following steps: putting a thymol-based hydrophobic deep-eutectic solvent into an aqueous solution containing malachite green, and extracting the malachite green under the conditions of constant temperature and stirring; the structural formula of the thymol-based hydrophobic deep-eutectic solvent is shown as a formula (I). The thymol-based hydrophobic eutecticevaporate solvent prepared by the preparation method disclosed by the invention has relatively strong trapping capability on malachite green; meanwhile, the eutectic solvent has good phase forming ability, and phase separation can be achieved with a small dosage. Under the condition that the volume ratio of the thymol-based hydrophobic deep-eutectic solvent to the aqueous solution is 1: 4, the recovery efficiency of the malachite green is as high as 98.12%. The thymol-based hydrophobic deep-eutectic solvent extraction agent has the advantages of high separation efficiency, environmental friendliness and low price. # imgabs0 #

Description

Technical Field

[0001] The invention relates to the field of low eutectic solvents, and in particular to application of a thymol-based hydrophobic low eutectic solvent in extracting malachite green. Background Art

[0002] Every year, industries such as plastics, printing, textiles, leather, cosmetics, dyes and pigments manufacturing discharge millions of tons of colored wastewater. The release of dyes into the environment is a serious problem because they can stain natural water bodies and have harmful effects on humans, animals and plants. Therefore, the removal of colored dyes from wastewater is essential to improve water quality and protect the environment. Malachite green is a cationic dye contained in colored wastewater, so it is crucial to extract malachite green from colored wastewater.

[0003] Deep eutectic solvents are a new type of "green solvent" that is directly mixed with hydrogen bond acceptors such as quaternary ammonium salts and hydrogen bond donors such as polyols, amides, and carboxylic acids. Deep eutectic solvents not only have similar physical and chemical properties to ionic liquids, such as low vapor pressure, low volatility, and designable structural properties, but also have low raw material costs, simple preparation, and good biocompatibility, providing a new platform for the development of separation technology.

[0004] The hydrophobic low eutectic solvent has functional groups that interact with malachite green and has a strong capture ability for malachite green; at the same time, the hydrophobic low eutectic solvent has good phase-forming ability and can achieve phase separation at a small dosage. The thymol-based hydrophobic low eutectic solvent can form hydrogen bonds with malachite green and has a strong capture ability for cationic dye substances. It provides an effective way to extract malachite green from wastewater. Summary of the invention

[0005] The invention can effectively extract malachite green in wastewater, and has the advantages of simple operation, low cost, high purity and strong stability.

[0006] To achieve the above object, the technical solution adopted by the present invention is: use of a thymol-based hydrophobic deep eutectic solvent in the extraction of malachite green, the method is as follows: placing the thymol-based hydrophobic deep eutectic solvent in an aqueous solution containing malachite green, extracting malachite green under constant temperature and stirring conditions; the structural formula of the synthesized thymol-based hydrophobic deep eutectic solvent is shown in formula (I):

[0007]

[0008] The above-mentioned thymol-based hydrophobic low eutectic solvent is used in the extraction of malachite green. The volume ratio of thymol-based hydrophobic low eutectic solvent: aqueous solution containing malachite green is 1:4. In the aqueous solution containing malachite green, the concentration of malachite green is 200 ppm.

[0009] The above-mentioned use of a thymol-based hydrophobic low eutectic solvent in the extraction of malachite green, wherein the constant temperature is 30°C.

[0010] The use of the above-mentioned thymol-based hydrophobic deep eutectic solvent in the extraction of malachite green, the preparation method of the thymol-based hydrophobic deep eutectic solvent is as follows:

[0011] Thymol and n-propanol are mixed and stirred to react until a uniform transparent liquid is formed, and then vacuum dried to obtain a target low eutectic solvent.

[0012] The above-mentioned green and economical hydrophobic low eutectic solvent is used in the extraction of malachite green, with a molar ratio of thymol to n-propanol of 1:1.

[0013] In the application of the above-mentioned green and economical hydrophobic low eutectic solvent in the extraction of malachite green, the stirring reaction temperature is 60°C.

[0014] The above-mentioned green and economical hydrophobic low eutectic solvent is used in the extraction of malachite green, and the reaction time is 1 hour.

[0015] Compared with the prior art, the present invention has the following significant advantages:

[0016] 1. The thymol-based hydrophobic low eutectic solvent prepared by the present invention has a wide liquid range, is non-volatile, is an excellent green solvent, and reduces energy consumption and environmental pollution.

[0017] 2. The thymol-based hydrophobic low eutectic solvent prepared by the present invention has a strong capture ability for malachite green; at the same time, the hydrophobic low eutectic solvent has a good phase-forming ability and can achieve phase separation at a relatively small dosage.

[0018] 3. The thymol hydrophobic low eutectic solvent prepared by the present invention can form hydrogen bonds with malachite green, thereby achieving the purpose of efficiently extracting and separating malachite green.

[0019] 4. The thymol-based hydrophobic low eutectic solvent prepared by the present invention has low price, good chemical stability, wide liquid range and high extraction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 1 is the hydrogen spectrum of the thymol-based hydrophobic deep eutectic solvent prepared in Example 1.

[0021] Figure 2 This is the infrared spectrum of the thymol-based hydrophobic deep eutectic solvent prepared in Example 1.

[0022] Specific implementation method

[0023] The present invention is further described below by way of specific examples. The present invention is not limited to the embodiments, and slight variations are possible without departing from the scope described.

[0024] Example 1 A thymol-based hydrophobic deep eutectic solvent for extracting malachite green

[0025] The preparation method is as follows:

[0026] Thymol and n-propanol were weighed in a molar ratio of 1:1 and placed in a sample bottle. Stirred and reacted at 60°C for 1 hour to form a uniform transparent liquid. Vacuum dried at 0.09 MPa and 60°C for 48 hours to obtain the final product, thymol-n-propanol (molar ratio 1:1) hydrophobic low eutectic solvent.

[0027] Characterization of Thymol Hydrophobic Deep Eutectic Solvent:

[0028] (1) Hydrogen spectrum: Hydrophobic deep eutectic solvent NMR hydrogen spectrum of thymol-n-propanol (molar ratio 1:1) 1 H NMR characterization (300 MHz, solvent: DMSO-d 6 )See Figure 1 . For H NMR spectrum analysis, 1 The chemical shift and the number of resonance peaks of H NMR were consistent with those of the target hydrophobic deep eutectic solvent, and no impurity peaks were found.

[0029] (2) IR spectrum: IR characterization of thymol-n-propanol (molar ratio 1:1) hydrophobic deep eutectic solvent is shown in Figure 2 . Analysis of the infrared spectrum shows that the infrared spectrum of the low eutectic solvent contains both the characteristic peaks of the hydrogen bond acceptor (n-propanol) and the characteristic absorption peaks of the hydrogen bond donor (thymol), and no new characteristic peaks are generated, indicating that no chemical reaction occurs between thymol and n-propanol to produce new substances, but they are only combined through hydrogen bond interactions.

[0030] Example 2 Application of thymol-based hydrophobic deep eutectic solvent to extract malachite green

[0031] (I) Extraction and separation experiment

[0032] Take a certain amount of malachite green and dissolve it in water to prepare a malachite green solution with a malachite green concentration of 200ppm for later use, transfer 1mL of thymol-based hydrophobic low eutectic solvent into a 10mL graduated test tube, and then add 4mL of malachite green aqueous solution, the volume ratio of thymol-based hydrophobic low eutectic solvent to malachite green is 1:4. Perform the extraction and separation experiment of malachite green at 30℃ with magnetic stirring.

[0033] After extraction for 30 minutes, let it stand for 60 minutes. Use UV-visible spectrophotometry to measure the concentration of malachite green in the aqueous phase at a wavelength of 620nm. Take at least 3 samples from the aqueous phase for quantitative determination, and control the relative error within 3% at equilibrium to ensure the accuracy of the data. The extraction efficiency (E%) of malachite green is calculated according to the following formula (1-1):

[0034]

[0035] Among them, C 0 represents the initial concentration of malachite green in water, C f is the concentration of residual malachite green in the aqueous phase.

[0036] (II) Extraction rate of malachite green by thymol-based hydrophobic deep eutectic solvent

[0037] After extraction with thymol-based hydrophobic low eutectic solvent, the extraction rate of malachite green with thymol-based low eutectic solvent was calculated to be 98.12%.

Claims

1. Use of a thymol-based hydrophobic deep eutectic solvent in extracting malachite green, characterized in that: The method is as follows: placing a thymol-based hydrophobic deep eutectic solvent in an aqueous solution containing malachite green, and extracting the malachite green under constant temperature and stirring conditions; The structural formula of the thymol-based hydrophobic deep eutectic solvent is shown in formula (I):

2. The use of a thymol-based hydrophobic deep eutectic solvent in extracting malachite green according to claim 1, characterized in that: The volume ratio of thymol-based hydrophobic low eutectic solvent to the aqueous solution containing malachite green is 1:

4. In the aqueous solution containing malachite green, the concentration of malachite green is 200 ppm.

3. The use of a thymol-based hydrophobic deep eutectic solvent in extracting malachite green according to claim 1, characterized in that: The constant temperature is 30°C.

4. The use of a thymol-based hydrophobic deep eutectic solvent in extracting malachite green according to claim 1, characterized in that: The preparation method of the thymol-based hydrophobic deep eutectic solvent is as follows: Thymol and n-propanol are mixed and stirred to react until a uniform transparent liquid is formed, and then vacuum dried to obtain a target low eutectic solvent.

5. The use of a green and economical hydrophobic deep eutectic solvent in extracting malachite green according to claim 4, characterized in that: The molar ratio of thymol to n-propanol is 1:

1.

6. The use of a green and economical hydrophobic deep eutectic solvent in extracting malachite green according to claim 4, characterized in that: The temperature of the stirred reaction was 60°C.

7. The use of a green and economical hydrophobic deep eutectic solvent in extracting malachite green according to claim 4, characterized in that: The stirring reaction time is 1 h.

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