CN112452363B - Micro-fluidic chip for simulating soil-underground water heterogeneous system - Google Patents

Abstract

The invention provides a micro-fluidic chip for simulating a soil-underground water heterogeneous system, wherein a micro-fluidic chip main body is formed by bonding two pieces of glass and comprises a uniform flow area and a non-uniform flow area, two ends of the non-uniform flow area are respectively connected with a liquid inlet uniform flow area and a liquid outlet uniform flow area of the uniform flow area, the liquid inlet uniform flow area is connected with a liquid inlet through a liquid inlet channel, and the liquid outlet uniform flow area is connected with a liquid outlet through a liquid outlet channel; the non-uniform flow area consists of a high-permeability area and a low-permeability area, the high-permeability area is sandwiched between the two low-permeability areas and is communicated with the low-permeability areas, a plurality of cylinders are arranged in the uniform flow area and the non-uniform flow area, and gaps among the cylinders are fluid flow channels. The invention also provides a method for simulating the formation and repair of the non-aqueous phase pollutants in the soil-underground water heterogeneous system, solves the problem of poor repair effect caused by difficulty in determining the underground distribution condition of the non-aqueous phase pollutants, and lays a foundation for making an economic and efficient non-aqueous phase pollutant repair scheme.

Description

A microfluidic chip for simulating soil-groundwater heterogeneous systems

technical field

The invention relates to the technical field of soil organic pollution formation and restoration, in particular to a microfluidic chip for simulating a soil-groundwater heterogeneity system.

Background technique

In recent years, oil spill accidents have occurred frequently, leading to a large amount of toxic substances entering the soil, making soil oil pollution a global problem. As a typical Non-Aqueous Phase Liquid (NAPL), crude oil is extremely harmful to human health, and its solubility in water is low, its chemical activity is weak, and it has a high octanol/water partition coefficient (Kow). ), has strong binding ability with soil organic matter and strong anti-desorption ability, so crude oil can exist in soil for a long time. For soil-groundwater NAPL pollution, some in-situ (in-situ) remediation technologies (such as groundwater circulation well technology, surfactant-enhanced aquifer remediation technology) have also been proposed accordingly. Burial and heterogeneity, people often cannot grasp the distribution of non-aqueous pollutants in the ground, resulting in poor repair effect. Therefore, understanding the formation mechanism of the contamination layer of non-aqueous pollutants in soil-groundwater is crucial for proposing cost-effective remediation schemes. The flow and distribution of multiphase fluids in porous media can be widely used in the study of heterogeneous porous media.

SUMMARY OF THE INVENTION

Aiming at the problem that it is difficult to grasp the underground distribution of non-aqueous pollutants in the prior art, resulting in poor remediation effect, the present invention provides a microfluidic chip for simulating a soil-groundwater heterogeneous system.

To achieve the above object, the present invention adopts the following technical solutions:

A microfluidic chip for simulating a soil-groundwater heterogeneous system, the main body of the microfluidic chip is formed by bonding two pieces of glass of equal thickness, including a uniform flow area and a non-uniform flow area, and a uniform flow area Including the liquid inlet uniform flow area 3 and the liquid outlet uniform flow area 6, one end of the non-uniform flow area is connected with the liquid inlet uniform flow area 3, and the other end is connected with the liquid outlet uniform flow area 6. The liquid inlet uniform flow area 3 passes through the inlet. The liquid channel 2 is connected with the liquid inlet 1, and the liquid outlet uniform flow area 6 is connected with the liquid outlet 8 through the liquid outlet channel 7;

The non-uniform flow area is composed of a high-permeability area 5 and a low-permeability area 4, and is in a three-layer structure. Both the flow area 3 and the effluent uniform flow area 6 are trapezoidal structures;

The high-permeability zone 5 , the low-permeability zone 4 , the liquid inlet uniform flow zone 3 and the liquid outlet uniform flow zone 6 are all provided with a plurality of cylinders, and the gaps between the cylinders are fluid circulation channels.

Preferably, the thickness of the glass is 1 mm.

Preferably, the uniform flow area, the non-uniform flow area, the liquid inlet channel 2 and the liquid outlet channel 7 are all wet-etched on the top glass of the main body of the microfluidic chip.

Preferably, the cylinders in the high-permeability zone 5, the low-permeability zone 4 and the uniform flow zone are all arranged in an equilateral triangular matrix, wherein the cylinders in the high-permeability zone 5 have a diameter of 1.0575 mm and a height of 15 μm. The distance between the cylinders is 0.3mm; the diameter of the cylinders in the low permeability zone 4 is 0.2mm, the height is 15μm, and the distance between the cylinders is 0.005mm; the diameter of the cylinders in the uniform flow zone is 1mm and the height is 15μm , the spacing between the cylinders is 0.2115mm.

Preferably, the liquid inlet 1 and the liquid outlet 8 are both configured as cylinders with a diameter of 1 mm and a height of 1 mm.

Preferably, the liquid inlet channel 2 and the liquid outlet channel 7 are both set as rectangular parallelepipeds with a length of 4.3439 mm, a width of 0.95 mm and a height of 15 μm.

A method for simulating the formation of non-aqueous pollutants in a heterogeneous soil-groundwater system, using the above-mentioned microfluidic chip for simulating a heterogeneous soil-groundwater system, specifically comprising the following steps:

Step 1, using PEEK connector to connect the liquid inlet 1 of the microfluidic chip with the external pipeline;

Step 2, inject the ethanol solution into the liquid inlet 1, and discharge the gas in the microfluidic chip until the ethanol solution is saturated in the fluid circulation channel in the microfluidic chip;

Step 3, inject deionized water into the liquid inlet 1, and discharge the ethanol solution in the microfluidic chip until the fluid flow channel in the microfluidic chip is saturated with deionized water;

Step 4, inject the mineral oil dyed with Oil Red O into the liquid inlet 1, and discharge the deionized water in the microfluidic chip until the mineral oil is saturated in the fluid flow channel in the microfluidic chip;

Step 5, set multiple flow rates, inject deionized water into the liquid inlet 1 according to different flow rates respectively, and use ImageJ image processing software to process to obtain the formation of non-aqueous pollutants in the microfluidic chip under different flow rate conditions.

A method for remediating non-aqueous pollutants in a simulated soil-groundwater heterogeneous system, using the above-mentioned microfluidic chip for simulating a soil-groundwater heterogeneous system, specifically comprising the following steps:

Step 1, using PEEK connector to connect the liquid inlet 1 of the microfluidic chip with the external pipeline;

Step 2, inject the ethanol solution into the liquid inlet 1, and discharge the gas in the microfluidic chip until the ethanol solution is saturated in the fluid circulation channel in the microfluidic chip;

Step 3, inject deionized water into the liquid inlet 1, and discharge the ethanol solution in the microfluidic chip until the fluid flow channel in the microfluidic chip is saturated with deionized water;

Step 4, inject the mineral oil dyed with Oil Red O into the liquid inlet 1, and discharge the deionized water in the microfluidic chip until the mineral oil is saturated in the fluid flow channel in the microfluidic chip;

Step 5, set multiple flow rates, inject deionized water into the liquid inlet 1 according to different flow rates respectively, and use ImageJ image processing software to process to obtain the formation of non-aqueous pollutants in the microfluidic chip under different flow rate conditions;

Step 6, respectively inject Tween 80 solution into the liquid inlet 1 according to the flow rate set in step 5, and use ImageJ image processing software to process, to obtain the removal situation and residual of non-aqueous phase pollutants in the microfluidic chip under different flow rate conditions Happening.

Preferably, the concentration of the Tween 80 solution is 1 g/L.

Beneficial technical effects brought by the present invention:

The present invention proposes a microfluidic chip for simulating a soil-groundwater heterogeneous system. The regions in the microfluidic chip are connected to each other through microchannels to form a complete system. At the same time, the present invention also utilizes the microfluidic chip. The microfluidic chip realizes the real-time simulation of the formation and remediation process of the non-aqueous contamination layer in the soil-groundwater heterogeneous system, and solves the difficulty of the existing technology to determine the subsurface distribution of the non-aqueous contaminants. Therefore, it has laid a foundation for proposing a cost-effective non-aqueous pollutant remediation scheme.

Description of drawings

FIG. 1 is a schematic structural diagram of a microfluidic chip for simulating a soil-groundwater heterogeneous system according to the present invention.

In the figure: 1- liquid inlet, 2- liquid inlet channel, 3- liquid inlet uniform flow area, 4- low osmotic zone, 5- high osmotic zone, 6- liquid uniform flow area, 7- liquid outlet channel, 8 - Liquid outlet.

Detailed ways

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

A microfluidic chip for simulating a soil-groundwater heterogeneous system, as shown in Figure 1, the main body of the microfluidic chip is formed by bonding two pieces of glass with a thickness of 1 mm, and the main body of the microfluidic chip includes Uniform flow area and non-uniform flow area. The uniform flow area includes the liquid inlet uniform flow area 3 and the liquid outlet uniform flow area 6. One end of the non-uniform flow area is connected with the liquid inlet uniform flow area 3, and the other end is connected with the liquid uniform flow area. 6 is connected, the liquid inlet uniform flow area 3 is connected with the liquid inlet 1 through the liquid inlet channel 2, and the liquid outlet uniform flow area 6 is connected with the liquid outlet 8 through the liquid outlet channel 7.

The non-uniform flow area is composed of a high-permeability area 5 and a low-permeability area 4, and is in a three-layer structure. Both the flow area 3 and the outflow uniform flow area 6 are trapezoidal structures, and the upper bottom of the trapezoidal structure is 0.95 mm, the lower bottom is 14.1471 mm, and the height is 5.8456 mm.

The high permeability zone 5, the low permeability zone 4, the liquid inlet uniform flow zone 3, the liquid outlet uniform flow zone 6, the liquid inlet channel 2 and the liquid outlet channel 7 are all wet-etched on the top glass of the main body of the microfluidic chip. ; A plurality of cylinders are arranged in the high-permeability zone 5, the low-permeability zone 4, the liquid inlet uniform flow zone 3 and the liquid outlet uniform flow zone 6, and each cylinder is sandwiched between two pieces of glass. Among them, the high-permeability zone 5 The diameter of the inner cylinder is 1.0575mm, the height is 15μm, and the spacing between the cylinders is 0.3mm; the diameter of the cylinder in the low-permeability zone 4 is 0.2mm, the height is 15μm, and the spacing between the cylinders is 0.005mm ; The diameter of the cylinders in the inflow and outflow equalization areas is 1mm, the height is 15μm, and the distance between the cylinders is 0.2115mm; the space between the cylinders is the fluid circulation channel, and the height of the fluid circulation channel The height of the fluid circulation channel is the same as that of the cylinder, that is, the height of the fluid circulation channel is 15 μm, and the width of the fluid circulation channel is the distance between two adjacent cylinders.

The liquid inlet 1 and the liquid outlet 8 are both configured as cylinders with a diameter of 1 mm and a height of 1 mm; the liquid inlet channel 2 and the liquid outlet channel 7 are both configured as rectangular parallelepipeds with a length of 4.3439 mm, a width of 0.95 mm and a height of 15 μm.

Example 1

A method for simulating the formation of non-aqueous pollutants in a heterogeneous soil-groundwater system, using the above-mentioned microfluidic chip for simulating a heterogeneous soil-groundwater system, specifically comprising the following steps:

Step 1, use a PEEK connector to connect the liquid inlet 1 of the microfluidic chip with an external pipeline.

Step 2, inject ethanol solution into the liquid inlet 1, and discharge the gas in the microfluidic chip until the ethanol solution is saturated in the fluid flow channel in the microfluidic chip.

Step 3, inject deionized water into the liquid inlet 1, and discharge the ethanol solution in the microfluidic chip until the deionized water is saturated in the fluid flow channel in the microfluidic chip.

Step 4, inject the mineral oil dyed with Oil Red O into the liquid inlet 1, and discharge the deionized water in the microfluidic chip until the mineral oil is saturated in the fluid flow channel in the microfluidic chip.

Step 5: Set the flow rate of injected deionized water to 10 μL/h, 20 μL/h, and 40 μL/h, and inject the water into the microfluidic chip inlet 1 at the flow rates of 10 μL/h, 20 μL/h, and 40 μL/h, respectively. Ionized water, using ImageJ image processing software to analyze and correct the light intensity of the background noise, as shown in formula (1), by correcting the light intensity of the background noise, the slight fluctuation of the intensity of the arc light source in the microscope system is corrected, so as to obtain the light intensity under different flow rate conditions. The formation of non-aqueous pollutants in the fluidic chip;

The background noise light intensity correction formula is as follows;

表示实际测量背景噪点光强度的校正值；I_j表示实际测量背景噪点的光强度；I₀表示背景噪点值；I_F表示充满非水相污染物时微流控芯片的光强。In the formula,

Represents the correction value of the light intensity of the actual measured background noise; I _j represents the light intensity of the actual measured background noise; I ₀ represents the value of the background noise; _IF represents the light intensity of the microfluidic chip when it is filled with non-aqueous pollutants.

Example 2

A method for remediating non-aqueous pollutants in a simulated soil-groundwater heterogeneous system, using the above-mentioned microfluidic chip for simulating a soil-groundwater heterogeneous system, specifically comprising the following steps:

Step 1, use a PEEK connector to connect the liquid inlet 1 of the microfluidic chip with an external pipeline.

Step 2, inject ethanol solution into the liquid inlet 1, and discharge the gas in the microfluidic chip until the ethanol solution is saturated in the fluid flow channel in the microfluidic chip.

Step 3, inject deionized water into the liquid inlet 1, and discharge the ethanol solution in the microfluidic chip until the deionized water is saturated in the fluid flow channel in the microfluidic chip.

Step 4, inject the mineral oil dyed with Oil Red O into the liquid inlet 1, and discharge the deionized water in the microfluidic chip until the mineral oil is saturated in the fluid flow channel in the microfluidic chip.

Step 5, inject deionized water into the liquid inlet 1 of the microfluidic chip according to the flow rates of 10 μL/h, 20 μL/h and 40 μL/h respectively, and use ImageJ image processing software to process to obtain the microfluidic control under different flow rate conditions. Formation of non-aqueous contaminants within the chip.

In step 6, Tween 80 solution with a concentration of 1 g/L was injected into the microfluidic chip inlet 1 at the flow rates of 10 μL/h, 20 μL/h and 40 μL/h respectively, and the experimental images were processed by ImageJ image processing software. Treatment was performed to obtain the removal and residual conditions of non-aqueous pollutants in the microfluidic chip under different flow rate conditions.

Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the essential scope of the present invention should also belong to the present invention. the scope of protection of the invention.

Claims (8)

1. A micro-fluidic chip for simulating a soil-underground water heterogeneous system is characterized in that a micro-fluidic chip main body is formed by bonding two pieces of glass with equal thickness and comprises a uniform flow area and a non-uniform flow area, wherein the uniform flow area comprises a liquid inlet uniform flow area (3) and a liquid outlet uniform flow area (6), one end of the non-uniform flow area is connected with the liquid inlet uniform flow area (3), the other end of the non-uniform flow area is connected with the liquid outlet uniform flow area (6), the liquid inlet uniform flow area (3) is connected with a liquid inlet (1) through a liquid inlet channel (2), and the liquid outlet uniform flow area (6) is connected with a liquid outlet (8) through a liquid outlet channel (7);

the non-uniform flow area consists of a high-permeability area (5) and a low-permeability area (4) and is of a three-layer structure, and the high-permeability area (5) is sandwiched between the two low-permeability areas (4) and is communicated with the low-permeability areas (4); the liquid inlet uniform flow area (3) and the liquid outlet uniform flow area (6) are both in a trapezoidal structure;

a plurality of cylinders are arranged in the high-permeability area (5), the low-permeability area (4), the liquid inlet uniform flow area (3) and the liquid outlet uniform flow area (6), and gaps among the cylinders are fluid circulation channels;

the cylinders in the high-permeability area (5), the low-permeability area (4) and the uniform flow area are all arranged in an equilateral triangle matrix, wherein the diameter of the cylinder in the high-permeability area (5) is 1.0575mm, the height of the cylinder is 15 mu m, and the distance between the cylinders is 0.3 mm; the diameter of the cylinder in the hypotonic region (4) is 0.2mm, the height is 15 mu m, and the distance between the cylinders is 0.005 mm; the diameter of the inner cylinder of the uniform flow area is 1mm, the height is 15 μm, and the distance between the cylinders is 0.2115 mm.

2. The microfluidic chip for simulating a soil-groundwater heterogeneous system according to claim 1, wherein the glass thickness is 1 mm.

3. The microfluidic chip for simulating the soil-groundwater heterogeneous system according to claim 1, wherein the uniform flow region, the non-uniform flow region, the liquid inlet channel (2) and the liquid outlet channel (7) are etched on the top glass of the microfluidic chip body by a wet method.

4. A microfluidic chip for simulating a soil-groundwater heterogeneous system according to claim 1, wherein the liquid inlet (1) and the liquid outlet (8) are both arranged as cylinders with a diameter of 1mm and a height of 1 mm.

5. A microfluidic chip for simulating a soil-groundwater heterogeneous system according to claim 1, wherein the liquid inlet channel (2) and the liquid outlet channel (7) are both provided in a cuboid shape with a length of 4.3439mm, a width of 0.95mm and a height of 15 μm.

6. A method for simulating the formation of non-aqueous phase pollutants in a soil-groundwater heterogeneous system is characterized in that the microfluidic chip for simulating the soil-groundwater heterogeneous system disclosed in claim 1 is adopted, and the method comprises the following steps:

step 1, connecting a liquid inlet (1) of a microfluidic chip with an external pipeline by using a PEEK joint;

step 2, injecting an ethanol solution into the liquid inlet (1), and discharging gas in the microfluidic chip until the fluid circulation channel in the microfluidic chip is saturated with the ethanol solution;

step 3, injecting deionized water into the liquid inlet (1), and discharging an ethanol solution in the microfluidic chip until the fluid circulation channel in the microfluidic chip is saturated with deionized water;

step 4, injecting Oil Red O dyed mineral Oil into the liquid inlet (1), and discharging deionized water in the microfluidic chip until mineral Oil is saturated in a fluid circulation channel in the microfluidic chip;

and step 5, setting multiple flow rates, injecting deionized water into the liquid inlet (1) according to different flow rates, and processing by using ImageJ image processing software to obtain the formation condition of the non-aqueous phase pollutants in the microfluidic chip under different flow rate conditions.

7. The method for repairing non-aqueous phase pollutants in a soil-groundwater heterogeneous system is characterized in that the microfluidic chip for simulating the soil-groundwater heterogeneous system in claim 1 is adopted, and the method specifically comprises the following steps:

step 1, connecting a liquid inlet (1) of a microfluidic chip with an external pipeline by using a PEEK joint;

step 2, injecting an ethanol solution into the liquid inlet (1), and discharging gas in the microfluidic chip until the fluid circulation channel in the microfluidic chip is saturated with the ethanol solution;

step 3, injecting deionized water into the liquid inlet (1), and discharging an ethanol solution in the microfluidic chip until the fluid circulation channel in the microfluidic chip is saturated with deionized water;

step 4, injecting Oil Red O dyed mineral Oil into the liquid inlet (1), and discharging deionized water in the microfluidic chip until mineral Oil is saturated in a fluid circulation channel in the microfluidic chip;

step 5, setting multiple flow rates, respectively injecting deionized water into the liquid inlet (1) according to different flow rates, and processing by ImageJ image processing software to obtain the formation condition of non-aqueous phase pollutants in the microfluidic chip under different flow rate conditions;

and 6, injecting a Tween 80 solution into the liquid inlet (1) according to the flow rate set in the step 5, and processing by using ImageJ image processing software to obtain the removal condition and the residual condition of the non-aqueous phase pollutants in the microfluidic chip under different flow rate conditions.

8. The method for remediating non-aqueous phase contaminants in a soil-groundwater heterogeneous system as claimed in claim 7, wherein the concentration of the tween 80 solution is 1 g/L.

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