CN1171654C - Leaching method for rapid leaching of solutes in porous media - Google Patents

Abstract

The present invention provides a leaching method for quickly extracting solutes from porous mediums, and relates to a leaching method for strengthening the mass transfer of the porous mediums by utilizing micro counterflow caused by the solubility effect among mutual solvents. The method selects a leaching solvent A and a mutual solvent B thereof which have good dissolving capability on the solutes. Firstly, a small quantity of solution solvent B enables the porous mediums to be swelled and saturated; then, the outside solvent of the porous medium is switched into the leaching solvent A for leaching by a method of adding the leaching solvent A or other methods. The leaching method has the advantages of high leaching speed, high yield, moderate condition, strong selectivity, low cost and easy implementation, is especially suitable to leach plant medicinal materials and other natural resources by taking polycomponent extracts as targets, and is a novel porous material inside mass transfer strengthening technology with high efficiency.

Description

Leaching method for rapid leaching of solutes in porous media

technical field

The invention belongs to the technical field of chemical mass transfer and separation, and in particular relates to a leaching method for enhancing mass transfer in porous media by using micro-convection caused by the dissolution effect between mutual-soluble solvents.

Background technique

Porous media refers to solid materials that contain many tiny pores inside. Many substances in nature have a porous structure, such as soil, wood, botanicals and minerals. With the popularization and deepening of the development and utilization of natural renewable resources, such as the extraction of effective components of Chinese medicinal materials, especially the energy and resources needed by people will increasingly come from natural porous materials, and the development of porous media suitable The efficient and fast leaching method has universal significance. The main factors affecting the mass transfer of porous media are the microporous structure of the material and the properties of the fluid in the pores and the interaction between them. The existence of the skeleton structure prevents the mass transfer behavior in porous materials from being strengthened by general methods. At present, there are two main methods used: one is to reduce the macroscopic size of porous media. This method can appropriately reduce the mass transfer resistance in the channel, but it cannot essentially change the flow mode in the channel, and the material The reduction in the size of the porous medium may increase the difficulty of solid-liquid separation; the other is to apply external fields with strong penetrating power, such as ultrasonic waves and microwaves, which can cause activation and disturbance of solvent and solute molecules inside porous media. . The above two methods can achieve the purpose of improving the leaching efficiency of valuable components, but they also increase the leaching of ineffective components (impurities), which brings difficulties to the downstream separation and purification; the thermal effect caused by the external field will destroy temperature-sensitive solutes, pretreatment Problems such as high cost or difficult process scale-up. Therefore, it is extremely necessary to develop a method for leaching strengthening.

Contents of the invention

The purpose of this invention is to provide a kind of leaching method that is used for the fast leaching of solute in porous media, promptly utilizes the interaction between the better solvent of mutual solubility to strengthen the leaching method of solute transmission in porous media, this method not only has The leaching speed is fast, the yield is high, and the conditions are mild, the cost is low, and it is easy to implement.

The technical scheme of the present invention is as follows: a leaching method for rapid leaching of solutes in porous media, characterized in that the method comprises the following steps:

(1) Select leaching solvent A, select the auxiliary solvent B that is miscible with A or easily soluble in A and can dissolve the solute in the porous medium, wherein: solvent B is different from solvent A, and the dissolution process from solvent A to solvent B is fast; The porous medium described above is a Chinese herbal medicine, and the solute is an active ingredient in the Chinese herbal medicine;

(2) first add auxiliary solvent B to the porous medium, and keep until the porous medium reaches swelling saturation;

(3) Switch the external solvent of the porous medium to A for leaching.

The leaching solvent A or auxiliary solvent B is a solvent or a mixed solution of several solvents.

There are two switching modes described in step (3) of the present invention: one is to directly add solvent A to the container; Solvent A.

The Chinese medicinal materials described in the present invention include herbal pieces and their roughly processed granules, which require no close chemical combination between the solute and the matrix.

The principle of the present invention is: 1. The mutual diffusion of solvents inside and outside the porous medium will drive the migration of solutes; for convective diffusion.

Compared with the prior art, the present invention has the following advantages and outstanding effects: the present invention is applied to the leaching of solutes in porous media, has the characteristics of fast leaching speed, sufficient leaching, and easy realization, and can be used at or near room temperature implemented at a temperature. Based on the requirements of the solvent switching method on the porous medium itself and the internal and external environment, the present invention is very suitable for extracting active ingredients in natural plants, especially medicinal plants targeting multi-component extracts. Utilizing the invention, the effective mass transfer coefficient in the pores of the porous medium can be increased from 10 ^-9 m ² /s to 10 ^-7 m ² /s, and the effective diffusion coefficient in the dense pore walls can also be increased by 1 to 2 orders of magnitude.

Description of drawings

Fig. 1 is a schematic diagram of the principle of the present invention.

Fig. 2 is the schematic diagram of implementing the present invention by adopting solvent addition method.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

The present invention can be implemented in a static or dynamic manner under normal pressure, and the implementation steps include:

(1) Determine the leaching solvent A according to the physical and chemical properties of the porous medium and the solute therein, and select an auxiliary solvent B that is miscible with A or easily soluble in A and can dissolve the solute in the porous medium C;

(2) Add auxiliary solvent B to porous medium C until swelling saturation is reached;

(3) Switch the external solvent of the porous medium C to the leaching solvent A for leaching.

Wherein, the standard for selecting auxiliary solvent B is:

a.B is readily soluble or miscible with A.

b.B is a good solvent for the main valuable components in the porous medium C.

c. The dissolution process of A to B is very fast.

Description of the implementation process:

Put the porous medium material C in the container, add B and keep it until the porous medium C reaches swelling saturation.

There are two optional ways to switch the external solvent B of porous medium C to A.

Method 1: Add A directly to the container.

Method 2: Remove B outside the porous medium by filtration or centrifugation before adding A.

The switching process has no special requirement on the time, and it is allowed to be completed as soon as possible within the range allowed by the equipment.

Mode 1 can also be realized in a dynamic way: place porous medium C in a fixed bed leacher (such as a percolator), let B slowly pass through the bed in a certain direction, and switch to A at an appropriate time.

The above process can be carried out at or near room temperature.

Example:

(1) Acid chrome blue K is used as the solute and tracer, the solvent B is water or methanol, and the dosage is 0.4mL. The leaching solvent A is methanol, acetone, ethanol or water, and the dosage is 20mL. B is filled with 20 tubes with an inner diameter of 0.5 mm capillary, use A to leach the solute in the capillary, and the solvent switching method is to remove the external solvent B and then add solvent A.

The experimental results are shown in the table below: Solvent A Initial concentration Ppm Solvent B Mass transfer time S Bulk concentration ppm Effective diffusion coefficient, D _eff m ² /s water 1750 water 300 0.464 5.00×10 ^-9 Methanol 1750 Methanol 120 0.518 1.55×10 ^-8 ethanol 1750 water 60 2.840 9.00×10 ^-7 Methanol 1750 water 60 1.850 3.85×10 ^-7 acetone 1750 water 60 2.630 7.70×10 ^-7

It can be seen from the table that the application of the present invention can effectively accelerate the leaching speed of the solute, and the effective diffusion coefficient is greatly improved.

(2) Taking rhubarb rhubarb as the object, the dosage of dry medicinal materials is 1.0g, the total anthraquinone is the solute to be investigated, the solvent A is water, the dosage is 200mL, the solvent B is ethanol, the leaching temperature is 60°C, and the solvent switching method is directly adding solvent A The way. The experimental results are shown in the table below. direct leaching Solvent switching Leaching time min Leaching solution concentration ppm Extraction rate 100×g/g Leaching time min Leaching solution concentration ppm Extraction rate 100×g/g 1 27.5 0.55 1 31.6 0.63 2 36.5 0.73 2 37.4 0.75 6 46.5 0.93 8 52.8 1.06 16 55 1.1 16 63.2 1.26 32 58.5 1.17 32 65.2 1.30 64 61 1.22 64 63.4 1.27 120 61.5 1.23 120 71.8 1.44

As can be seen from the table, the time required for the application of the present invention to reach the same extraction rate is short, and the extraction rate in the same time is high.

(3) Taking rhubarb rhubarb as the object, the dosage of dry medicinal materials is 1.0g, the total anthraquinone is the solute to be investigated, the solvent A is ethanol, the dosage is 200mL, the solvent B is water, the leaching temperature is 60°C, and the solvent switching method adopts the external solvent The method of adding solvent A after removing B. The experimental results are shown in the table below. direct leaching Solvent switching Leaching time min Leaching solution concentration ppm Extraction rate 100×g/g Leaching time min Leaching solution concentration Ppm Extraction rate 100×g/g 1 23.5 0.47 1 40.0 0.8 8 28.0 0.56 2 52.5 1.05 16 35.5 0.71 4 103.0 2.06 32 39.5 0.79 16 106.5 2.13 64 49.5 0.99 32 102.5 2.05 120 54.5 1. 09 120 110.0 2.2

As can be seen from the table, the extraction rate when applying the present invention for 2 minutes is equivalent to that of direct leaching for 120 minutes, and the strengthening effect is obvious.

Claims (5)

1. be used for the leaching method of solute rapid leaching in porous media, it is characterized in that the method comprises the steps: (1) Select leaching solvent A, select the auxiliary solvent B that is miscible with A or easily soluble in A and can dissolve the solute in the porous medium, wherein: solvent B is different from solvent A, and the dissolution process from solvent A to solvent B is fast; The porous medium described above is a Chinese herbal medicine, and the solute is an active ingredient in the Chinese herbal medicine; (2) first add auxiliary solvent B to the porous medium, and keep until the porous medium reaches swelling saturation; (3) Switch the external solvent of the porous medium to A for leaching. 2. The leaching method for rapid leaching of solutes in porous media according to claim 1, wherein said leaching solvent A or auxiliary solvent B is a solvent or a mixed solution of several solvents. 3. The leaching method for rapid leaching of solutes in porous media according to claim 1, characterized in that the switching mode described in step (3) is: adding solvent A directly to the container. 4. According to the leaching method for the rapid leaching of solutes in porous media according to claim 1, it is characterized in that the switching mode described in step (3) is: first use filtration or centrifugation to filter and centrifuge the Solvent B was removed and solvent A was added. 5. The leaching method for rapid leaching of solutes in porous media according to claim 1, characterized in that: said Chinese herbal medicines include decoction pieces of Chinese herbal medicines and their rough-processed granules.

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