High-temperature regeneration method of column chromatography silica gel

Abstract

The invention belongs to the technical field of silica gel regeneration, and provides a high-temperature regeneration method of column chromatography silica gel. The method comprises the following steps: S1, pretreating used waste silica gel to remove organic impurities and residues adsorbed on the surface; s2, the pretreated waste silica gel is subjected to calcination treatment; s3, after calcining treatment is finished, naturally cooling to room temperature, and crushing and screening the regenerated silica gel; s4, sequentially soaking, centrifuging and drying the screened silica gel to obtain the column chromatography silica gel. Organic impurities and metal ions in the waste silica gel are removed through pretreatment, then the pore structure and the adsorption performance of the waste silica gel are recovered through high-temperature calcination, and finally the regenerated silica gel product is obtained through screening. The method is low in cost, environment-friendly and efficient, the specific surface area, pore volume and adsorption performance of the regenerated silica gel are equivalent to those of commercially available products, and the regenerated silica gel can be repeatedly used in the fields of drug separation, chemical purification and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of silica gel regeneration, and in particular to a method for high-temperature regeneration of column chromatography silica gel. Background Art

[0002] Column chromatography silica gel is a chromatographic technique based on the adsorption principle, which is widely used in fields such as chemical analysis, pharmaceutical industry, plant extraction, and biotechnology. Its main component is silicon dioxide (SiO2), which is made into high-purity white particles after fine processing. It has a porous structure and low impurity content, and can effectively separate and purify different components in complex mixtures. The separation principle of column chromatography silica gel is based on the difference in the adsorption force of substances on silica gel. Compounds with larger polarity have stronger affinity with silica gel and longer adsorption time; while compounds with smaller polarity have weaker affinity with silica gel and shorter adsorption time. By selecting a suitable mobile phase (such as petroleum ether, ethyl acetate, methanol, etc.), the separation of different compounds can be achieved.

[0003] When column chromatography silica gel adsorbs moisture or other organic impurities in the medium during use, when its adsorption effect cannot meet the requirements of purification and separation, different methods can be used for regeneration and then reused. However, the current regeneration methods have defects such as low efficiency, environmental pollution, limited number of regeneration times, physical damage, high cost, unstable effect, poor adaptability, and complex operation. Therefore, how to provide a method for regenerating column chromatography silica gel with simple steps and stable effect has become an urgent problem to be solved in this field. Summary of the Invention

[0004] In view of this, the present invention provides a method for high-temperature regeneration of column chromatography silica gel, and its purpose is to solve the technical problems such as low efficiency and unstable effect existing in the existing regeneration methods.

[0005] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0006] The present invention provides a method for high-temperature regeneration of column chromatography silica gel, including the following steps:

[0007] S1. Pretreat the used waste silica gel to remove the organic impurities and residues adsorbed on the surface;

[0008] S2. Calcinate the pretreated waste silica gel;

[0009] S3. After the calcination treatment is completed, naturally cool to room temperature, and crush and screen the regenerated silica gel;

[0010] S4. Soak, centrifuge, and dry the screened silica gel in sequence to obtain column chromatography silica gel.

[0011] Further, in the step S1, the pre-treatment steps include: soaking the waste silica gel in an acidic solution to remove metal ions, and then cleaning with an organic solvent to remove fat-soluble impurities.

[0012] Further, the acidic solution includes hydrochloric acid or nitric acid, and the soaking time in the acidic solution is 1 - 4 h;

[0013] The organic solvent includes one or more of ethanol, acetone, and chloroform.

[0014] Further, in the step S2, the calcination temperature is 400 - 800 °C, and the calcination time is 2 - 6 h.

[0015] Further, the heating rate from room temperature to the calcination temperature is 10 - 50 °C / min.

[0016] Further, in the step S3, the particle size of the sieved silica gel is 100 - 400 mesh.

[0017] Further, in the step S4, the solvent used for soaking is water, and the soaking time is 10 - 30 h.

[0018] Further, in the step S4, the drying temperature is 100 - 150 °C, and the drying time is 2 - 10 h.

[0019] Further, surface modification treatment is carried out on the column chromatography silica gel obtained in the step S4. The steps of the surface modification treatment include: impregnating the column chromatography silica gel in a silane coupling agent solution, and drying to obtain hydrophobic or hydrophilic modified column chromatography silica gel.

[0020] Further, the mass concentration of the silane coupling agent solution is 1 - 10%; the impregnation time is 30 - 120 min; the drying temperature is 60 - 120 °C, and the drying time is 1 - 4 h.

[0021] It can be seen from the above technical solutions that, compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] 1. Improve the regeneration efficiency: Through systematic pre-treatment and calcination treatment steps, this method can efficiently remove organic impurities and residues on the surface of waste silica gel. Especially in the pre-treatment step, soaking the waste silica gel in an acidic solution to remove metal ions, and then cleaning with an organic solvent to remove fat-soluble impurities. This dual cleaning mechanism greatly improves the thoroughness of impurity removal, thereby enhancing the purity and use efficiency of the regenerated silica gel.

[0023] 2. Enhance the performance of regenerated silica gel: The physical and chemical properties of the column chromatography silica gel regenerated by this method have been significantly improved. The calcination treatment can not only completely remove the residual organic matter but also restore the pore structure of the silica gel, making its adsorption capacity close to or even reach the level of new silica gel. Screening and subsequent soaking, centrifugation, and drying treatments further ensure the uniformity and stability of the regenerated silica gel, improving its separation effect in column chromatography applications.

[0024] 3. Save resources and costs: By regenerating waste silica gel, the present invention realizes the recycling of resources, reduces the consumption of new silica gel, and thus lowers the experimental and production costs. At the same time, the chemical reagents and energy consumption used in the regeneration process are relatively low, with high economic efficiency and environmental friendliness.

[0025] 4. Reduce environmental pollution: The recycling of waste silica gel reduces the generation of waste and environmental pollution. Compared with direct disposal or incomplete regeneration methods, the present invention can more effectively treat waste silica gel and reduce the potential harm of waste silica gel to the environment.

[0026] 5. Simple operation and easy to implement: This method has clear steps, simple operation, and is easy to implement in actual production and laboratory environments. The connection between each step is reasonable, and the equipment requirements are not high, making it suitable for large-scale popularization and application.

[0027] The silica gel regenerated by this method can significantly improve the quality of column chromatography products due to its high purity and good physical and chemical properties. Especially in the fields of fine chemicals, biomedicine, etc., high-quality column chromatography silica gel has a crucial impact on the purity and yield of products. Description of the Drawings

[0028] Figure 1 It is a comparison chart of the average pore diameters of the column chromatography silica gels prepared in Examples 1 - 5;

[0029] Figure 2 It is a comparison chart of the specific surface areas of the column chromatography silica gels prepared in Examples 1 - 5;

[0030] Figure 3 It is a comparison chart of the pore volumes of the column chromatography silica gels prepared in Examples 1 - 5. Detailed Embodiments

[0031] The present invention provides a high-temperature regeneration method for column chromatography silica gel, which includes the following steps:

[0032] S1. Pretreat the used waste silica gel to remove the organic impurities and residues adsorbed on the surface;

[0033] S2. Calcinate the pretreated waste silica gel;

[0034] S3. After the calcination treatment is completed, it is naturally cooled to room temperature, and the regenerated silica gel is crushed and screened;

[0035] S4. The screened silica gel is successively subjected to soaking, centrifugation, and drying treatments to obtain column chromatography silica gel.

[0036] In the present invention, in the step S1, the pretreatment steps include: soaking the waste silica gel with an acidic solution to remove metal ions, and then washing with an organic solvent to remove fat-soluble impurities.

[0037] In the present invention, the acidic solution includes hydrochloric acid or nitric acid, and the mass concentration of hydrochloric acid or nitric acid is 1-10%, preferably 2-8%, and more preferably 4-6%; the soaking time of the acidic solution is 1-4 h, preferably 2-3 h;

[0038] The organic solvent includes one or more of ethanol, acetone, and chloroform.

[0039] In the present invention, in the step S2, the calcination treatment temperature is 400-800 °C, preferably 450-700 °C, and more preferably 500-600 °C; the calcination treatment time is 2-6 h, preferably 3-5 h, and more preferably 4 h.

[0040] In the present invention, the heating rate from room temperature to the calcination treatment temperature is 10-50 °C / min, preferably 20-40 °C / min, and more preferably 30 °C / min; air or an inert gas is introduced during the calcination process to control the reaction atmosphere.

[0041] In the present invention, in the step S3, the particle size of the screened silica gel is 100-400 mesh, preferably 200-300 mesh.

[0042] In the present invention, in the step S4, the solvent used for soaking is water, and the soaking time is 10-30 h, preferably 15-25 h, and more preferably 20 h.

[0043] In the present invention, in the step S4, the drying temperature is 100-150 °C, preferably 110-140 °C, and more preferably 120-130 °C; the drying time is 2-10 h, preferably 4-8 h, and more preferably 6 h.

[0044] In the present invention, the column chromatography silica gel obtained in step S4 is subjected to surface modification treatment. The surface modification treatment steps include: impregnating the column chromatography silica gel in a silane coupling agent solution, and drying to obtain a hydrophobic or hydrophilic modified column chromatography silica gel.

[0045] In the present invention, the mass concentration of the silane coupling agent solution is 1 to 10%, preferably 2 to 8%, and more preferably 4 to 6%; the impregnation time is 30 to 120 min, preferably 50 to 100 min, and more preferably 60 to 80 min; the drying temperature is 60 to 120 °C, preferably 80 to 100 °C, and more preferably 90 °C; the drying time is 1 to 4 h, preferably 2 to 3 h.

[0046] In the present invention, the silane coupling agents for making column chromatography silica gel hydrophilic include KH-550 or KH-560; the silane coupling agents for making column chromatography silica gel hydrophobic include A-172, HY-903 or methyltrimethoxysilane.

[0047] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0048] Example 1

[0049] The waste silica gel was placed in a 2% hydrochloric acid solution and soaked for 4 h to remove metal ions; then it was washed with ethanol to remove fat-soluble impurities; the pretreated waste silica gel was placed in a muffle furnace for calcination, heated to 450 °C at a rate of 10 °C / min, and held for 6 h. Air was introduced during the calcination process to control the reaction atmosphere. After the calcination treatment, it was naturally cooled to room temperature to avoid the destruction of the silica gel structure caused by rapid cooling. The regenerated silica gel was mechanically crushed and screened using a vibrating screen to obtain silica gel with a particle size of 100 to 400 mesh. The silica gel was soaked in water for 10 h, then centrifuged to remove the suspended solids and impurities generated during the soaking process, and then dried at 100 °C for 10 h to obtain column chromatography silica gel.

[0050] KH-550 was dissolved in ethanol to prepare a silane coupling agent solution with a mass concentration of 2%. The column chromatography silica gel was immersed in the silane coupling agent solution for 30 min, and then the column chromatography silica gel was placed in a drying oven and dried at 60 °C for 4 h to obtain the modified column chromatography silica gel.

[0051] Example 2

[0052] The waste silica gel is placed in a 4% hydrochloric acid solution and soaked for 3 h to remove metal ions; then it is washed with acetone to remove fat-soluble impurities; the pretreated waste silica gel is placed in a muffle furnace for calcination, heated to 500 °C at a rate of 10 °C / min, and held for 5 h. Air is introduced during the calcination process to control the reaction atmosphere. After the calcination treatment, it is naturally cooled to room temperature to avoid damage to the silica gel structure caused by rapid cooling. The regenerated silica gel is mechanically crushed and screened using a multi-stage cyclone separator to obtain silica gel with a particle size of 100 - 400 mesh. The silica gel is soaked in water for 15 h, then centrifuged to remove the suspended solids and impurities generated during the soaking process, and then dried at 110 °C for 8 h to obtain column chromatography silica gel.

[0053] KH-560 is dissolved in ethanol to prepare a silane coupling agent solution with a mass concentration of 4%. The column chromatography silica gel is immersed in the silane coupling agent solution for 50 min, and then the column chromatography silica gel is placed in a drying oven and dried at 80 °C for 3 h to obtain modified column chromatography silica gel.

[0054] Example 3

[0055] The waste silica gel is placed in a 5% nitric acid solution and soaked for 2.5 h to remove metal ions; then it is washed with acetone to remove fat-soluble impurities; the pretreated waste silica gel is placed in a muffle furnace for calcination, heated to 550 °C at a rate of 20 °C / min, and held for 4 h. Air is introduced during the calcination process to control the reaction atmosphere. After the calcination treatment, it is naturally cooled to room temperature to avoid damage to the silica gel structure caused by rapid cooling. The regenerated silica gel is mechanically crushed and screened using a multi-stage cyclone separator to obtain silica gel with a particle size of 100 - 400 mesh. The silica gel is soaked in water for 20 h, then centrifuged to remove the suspended solids and impurities generated during the soaking process, and then dried at 120 °C for 5 h to obtain column chromatography silica gel.

[0056] A1-172 is dissolved in ethanol to prepare a silane coupling agent solution with a mass concentration of 5%. The column chromatography silica gel is immersed in the silane coupling agent solution for 60 min, and then the column chromatography silica gel is placed in a drying oven and dried at 90 °C for 2.5 h to obtain modified column chromatography silica gel.

[0057] Example 4

[0058] Place the waste silica gel in an 8% nitric acid solution and soak for 2 h to remove metal ions; then wash with chloroform to remove fat-soluble impurities; place the pretreated waste silica gel in a muffle furnace for calcination, heat to 600 °C at a rate of 20 °C / min, hold for 3 h, and introduce air during the calcination process to control the reaction atmosphere. After the calcination treatment, cool naturally to room temperature to avoid damage to the silica gel structure caused by rapid cooling. Crush the regenerated silica gel mechanically and screen it using a multi-stage cyclone separator to obtain silica gel with a particle size of 100-400 mesh. Soak the silica gel in water for 25 h, then perform centrifugation to remove the suspended matter and impurities generated during the soaking process, and then dry at 130 °C for 4 h to obtain column chromatography silica gel.

[0059] Dissolve HY-903 in acetone to prepare a silane coupling agent solution with a mass concentration of 6%. Immerse the column chromatography silica gel in the silane coupling agent solution for 80 min, and then place the column chromatography silica gel in an oven and dry at 100 °C for 2 h to obtain modified column chromatography silica gel.

[0060] Example 5

[0061] Place the waste silica gel in a 10% nitric acid solution and soak for 1 h to remove metal ions; then wash with chloroform to remove fat-soluble impurities; place the pretreated waste silica gel in a muffle furnace for calcination, heat to 650 °C at a rate of 20 °C / min, hold for 2 h, and introduce air during the calcination process to control the reaction atmosphere. After the calcination treatment, cool naturally to room temperature to avoid damage to the silica gel structure caused by rapid cooling. Crush the regenerated silica gel mechanically and screen it using a multi-stage cyclone separator to obtain silica gel with a particle size of 100-400 mesh. Soak the silica gel in water for 30 h, then perform centrifugation to remove the suspended matter and impurities generated during the soaking process, and then dry at 140 °C for 2 h to obtain column chromatography silica gel.

[0062] Dissolve methyltrimethoxysilane in acetone to prepare a silane coupling agent solution with a mass concentration of 8%. Immerse the column chromatography silica gel in the silane coupling agent solution for 100 min, and then place the column chromatography silica gel in an oven and dry at 120 °C for 1 h to obtain modified column chromatography silica gel.

[0063] Measure the average pore diameter, specific surface area, and pore volume of the column chromatography silica gels prepared in Examples 1-5 respectively. The measurement results are shown in Figure 1 、 Figure 2 and Figure 3 . Figures 1 to 3 It can be seen that the physical property parameters of the silica gel prepared by the present invention are consistent with those of the commonly used mesoporous silica gel, indicating that the technical solution of the present invention can regenerate silica gel.

[0064] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A high temperature regeneration method for column chromatography silica gel, characterized in that: The following steps are involved: S1. Pre-treat the used waste silica gel to remove organic impurities and residues adsorbed on the surface; S2, calcining the pretreated waste silica gel; S3, after the calcination treatment is completed, the silica gel is naturally cooled to room temperature, and the regenerated silica gel is crushed and sieved; S4. Soaking, centrifuging and drying the sieved silica gel in sequence to obtain column chromatography silica gel.

2. The high temperature regeneration method for column chromatography silica gel according to claim 1, characterized in that: In step S1, the pretreatment step includes: soaking the waste silica gel with an acidic solution to remove metal ions, and then washing with an organic solvent to remove fat-soluble impurities.

3. The high temperature regeneration method for column chromatography silica gel according to claim 2, characterized in that: The acidic solution includes hydrochloric acid or nitric acid, and the soaking time of the acidic solution is 1 to 4 hours; The organic solvent includes one or more of ethanol, acetone and chloroform.

4. The high temperature regeneration method for column chromatography silica gel according to any one of claims 1 to 3, characterized in that: In step S2, the calcination temperature is 400-800° C. and the calcination time is 2-6 hours.

5. The high temperature regeneration method for column chromatography silica gel according to claim 4, characterized in that: The heating rate from room temperature to the calcination temperature is 10 to 50° C. / min.

6. The high temperature regeneration method for column chromatography silica gel according to claim 5, characterized in that: In the step S3, the particle size of the silica gel after screening is 100-400 meshes.

7. The high temperature regeneration method for column chromatography silica gel according to claim 1 or 6, characterized in that: In step S4, the solvent used for soaking is water, and the soaking time is 10 to 30 hours.

8. The high temperature regeneration method for column chromatography silica gel according to claim 7, characterized in that: In step S4, the drying temperature is 100-150° C., and the drying time is 2-10 hours.

9. The high temperature regeneration method for column chromatography silica gel according to claim 7, characterized in that: The column chromatography silica gel obtained in step S4 is subjected to surface modification treatment, wherein the surface modification treatment step comprises: immersing the column chromatography silica gel in a silane coupling agent solution, and drying to obtain a hydrophobic or hydrophilic modified column chromatography silica gel.

10. The high temperature regeneration method for column chromatography silica gel according to claim 9, characterized in that: The mass concentration of the silane coupling agent solution is 1-10%; the immersion time is 30-120 minutes; the drying temperature is 60-120° C., and the drying time is 1-4 hours.

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