Continuous extraction device for reducing inorganic sulfide in soil and use method of continuous extraction device

Abstract

The invention provides a soil reducing inorganic sulfide continuous extraction device and a use method thereof. The extraction device comprises a brown reaction bottle, a first sealing bottle plug is arranged at a bottle opening of the brown reaction bottle, and a gas replacement needle, a sample injection needle and a liquid replacement needle are arranged on the first sealing bottle plug; the reagent deoxidizing bottle is connected with the sample injection needle through a first liquid flow divider and a first multi-channel injection pump; a second sealing bottle plug is arranged at a bottle opening of the reagent deoxidizing bottle, a first needle tube, a second needle tube and a third needle tube are respectively arranged on the second sealing bottle plug, a needle seat of the second needle tube is connected with a second two-way valve, the second two-way valve is connected with a first liquid diverter, the first liquid diverter is connected with a first multi-channel injection pump, and the second liquid diverter is connected with a second multi-channel injection pump. A channel of the first multi-channel injection pump is connected with an eighth two-way valve on the sample injection needle seat; and the absorption liquid deoxidizing bottle is connected with the liquid changing needle through a second liquid diverter and a second multi-channel injection pump. The detection efficiency and stability of the soil reducing inorganic sulfide are improved.

Description

Technical Field

[0001] This invention belongs to the field of soil and mineral geological exploration technology, specifically relating to the field of geological soil characteristic analysis, and particularly to a continuous extraction device for soil reducing inorganic sulfides and its usage method. Background Technology

[0002] Soil reducing inorganic sulfides are a core component of the sulfur biogeochemical cycle and are closely related to processes such as carbon mineralization, pyrite formation, phosphorus cycling, and heavy metal migration.

[0003] In related technologies, soil reducing inorganic sulfides include three forms: acid-volatile sulfur, chromium-reduced sulfur, and elemental sulfur. Acid-volatile sulfur is the most active component of reducing inorganic sulfides, readily releasing hydrogen sulfide under acidic conditions. Its content is significantly affected by microbial activity (such as sulfate-reducing bacteria) and season. Chromium-reduced sulfur mainly includes bound sulfur such as pyrite (FeS2), its formation is related to the dissimilatory reduction reaction of sulfate, and it has high stability in reducing environments, but may be oxidized to sulfate under oxidizing conditions. Elemental sulfur is an intermediate product of sulfide oxidation or partial reduction, often present as sulfur (S). 0 It exists in various forms, but its content is low and it is easily affected by environmental fluctuations.

[0004] Currently, rapid and quantitative analysis of soil reducing inorganic sulfides is of great significance for assessing the environmental risks and bioavailability of heavy metals, revealing key biogeochemical cycling processes such as sulfur cycle dynamics, iron-sulfur coupling, and carbon-sulfur coupling, indicating environmental changes and ecological responses, diagnosing the impacts of environmental changes, and optimizing remediation strategies for contaminated sites. This is also a key area of ​​focus and research in mineral geological exploration services.

[0005] In existing technologies, the main methods for extracting reducing inorganic sulfides from soil include distillation combined with nitrogen carrier gas and cold diffusion. Among these, distillation combined with nitrogen carrier gas is cumbersome and has low throughput, with risks of sulfur loss and transformation, posing safety hazards. Cold diffusion is safer than distillation, but traditional cold diffusion methods can only extract single samples, making it difficult to control reaction conditions. Furthermore, cold diffusion generally has a long reaction time, requiring multiple openings of the apparatus and repeated gas replacements when continuously extracting different forms of inorganic sulfides, making the process complex. Summary of the Invention

[0006] The purpose of this invention is to provide a continuous extraction device for soil reducing inorganic sulfides and its usage method, so as to solve the technical problems mentioned in the background art.

[0007] To achieve the above objectives, the embodiments of this application provide the following technical solutions.

[0008] According to one embodiment of this application, a continuous extraction apparatus for soil reducing inorganic sulfides is provided, comprising:

[0009] The brown reaction flask has a first sealing stopper at its mouth, and the first sealing stopper is equipped with a gas replacement needle, an injection needle, and a liquid replacement needle; a gas absorption cup is also provided at the bottom of the first sealing stopper.

[0010] The reagent deoxygenation bottle is connected to the injection needle via a first liquid distributor and a first multi-channel injection pump. A second sealing stopper is provided at the bottle mouth of the reagent deoxygenation bottle. A first needle tube, a second needle tube, and a third needle tube are respectively provided on the second sealing stopper. A second two-way valve is connected to the needle seat of the second needle tube. The second two-way valve is connected to the first liquid distributor. The first liquid distributor is connected to the first multi-channel injection pump. The channel of the first multi-channel injection pump is connected to an eighth two-way valve on the needle seat of the injection needle.

[0011] The absorbent deoxygenation bottle is connected to the liquid replacement needle via a second liquid distributor and a second multi-channel syringe pump. The bottle opening of the absorbent deoxygenation bottle is also equipped with a sealing stopper, and is connected to the second liquid distributor via the needle tube at the sealing stopper and the two-way valve on the needle seat. The second liquid distributor is connected to the second multi-channel syringe pump, and the channel of the second multi-channel syringe pump is connected to the third two-way valve on the needle seat of the liquid replacement needle.

[0012] Furthermore, it also includes a gas flow meter, one end of which is sequentially connected to a lower port of the gas flow meter and a fourth two-way valve, the fourth two-way valve being connected to a nitrogen source; the other end of the gas flow meter is connected to the first gas distributor via the upper port of the gas flow meter and a sixth two-way valve; the distribution port of the first gas distributor is connected to the second three-way valve on the needle seat of the gas replacement needle via a pipeline.

[0013] Furthermore, it also includes a vacuum gauge, one end of which is connected in sequence to the lower port of the vacuum gauge and the fifth two-way valve, and the fifth two-way valve is connected to the vacuum pump; the other end of the vacuum gauge is connected to the second gas distributor through the upper port of the vacuum gauge and the seventh two-way valve; the distribution port of the second gas distributor is connected to the second three-way valve on the needle seat of the gas replacement needle through a pipeline.

[0014] Furthermore, both the gas replacement needle and the injection needle have capillary tubes attached to their tips, which bypass the gas absorption cup and face the inner wall of the brown reaction flask.

[0015] The tip of the first syringe is connected to the second capillary tube, and the tip of the second syringe is connected to the first capillary tube. Both the first and second capillary tubes face the inner wall of the reagent deoxygenation bottle.

[0016] The three-way valve side port of the first multi-channel injection pump is connected to the first liquid distributor;

[0017] The three-way valve side port of the second multi-channel syringe pump is connected to the second liquid distributor.

[0018] According to another embodiment of this application, a method of using a continuous extraction device for soil reducing inorganic sulfides is provided, comprising the following steps:

[0019] Step S101: Perform an airtightness check on the extraction device;

[0020] Step S102: Weighing the sample and adding the absorption solution;

[0021] Step S103: Gas replacement to remove air from the brown reaction flask;

[0022] Step S104: Calculate the vacuum level and inject the corresponding sulfur form extraction reagent into the brown reaction flask;

[0023] Step S105: Remove the bottle rack (3) and incubate it in the dark at 30 degrees Celsius;

[0024] Step S106: After the culture is completed, the absorption liquid is replaced by using a gas flow meter in conjunction with a second multi-channel injection pump to complete the extraction of the first form of sulfide.

[0025] Step S107: Repeat steps S104-S106 in sequence to extract the second form of sulfide and the third form of sulfide. In step S106, the third form of sulfide is extracted only by the absorption liquid. Gas replacement is not repeated in the whole process.

[0026] Step S108: Calculate the content of different forms of reduced inorganic sulfides in the soil based on the sulfide concentration in the absorbent.

[0027] Furthermore, before the gas replacement in step S103, the nitrogen source pressure is adjusted to 0.02 MPa, and the flow rate of the gas flow meter is adjusted to 100 mL per minute. During gas replacement, the sixth two-way valve between the gas flow meter and the first gas distributor is closed, and the vacuum pump is turned on to draw the vacuum to -0.095 MPa. Subsequently, the fifth two-way valve between the vacuum pump and the vacuum gauge is closed, and the sixth two-way valve between the gas flow meter and the first gas distributor is opened to start charging nitrogen. After the gas flow meter rotor returns to the 0 mark, the sixth two-way valve between the gas flow meter and the first gas distributor is closed after 1 minute. The vacuum pump and the fifth two-way valve are opened again to perform a second vacuuming, completing the gas replacement process.

[0028] Furthermore, after three cycles of gas replacement, the pressure in the brown reaction bottle is reduced to the pressure calculated by the formula, based on the amount of reagent injected and the final required bottle pressure. Then, the reagent is injected into the brown reaction bottle through the injection needle using the first multi-channel injection pump.

[0029] After performing the above gas replacement process for 3 cycles, based on the amount of extract injected, evacuate the brown reaction flask to the vacuum level calculated by the formula, then close the second three-way valve. The formula for calculating the vacuum level is as follows:

[0030]

[0031]

[0032] In the formula, This represents the total volume of reagent injected in the first n injections; This represents the volume of reagent injected in the i-th injection; P represents the vacuum pressure; P represents the target bottle pressure after reagent injection. Indicates the initial volume of the reaction flask. This represents the total volume of the first n-1 injections;

[0033] Furthermore, in step S104, the step of injecting the corresponding extraction reagent into the brown reaction flask according to the extracted sulfur form includes:

[0034] Install the corresponding number of syringe pumps on the first multi-channel syringe pump and debug it. Connect the three-way valve side port of the syringe pump to the two-way valve on the reagent deoxygenation bottle. Insert the capillary tube connected to the two-way valve below the surface of the extracting reagent liquid.

[0035] Operate the first multi-channel syringe pump to extract the extraction reagent, rotate the valve of the first three-way valve corresponding to the first multi-channel syringe pump to close the side port connection, and then operate the first multi-channel syringe pump to purge the air in the capillary tube between the first multi-channel syringe pump and the eighth two-way valve.

[0036] Connect the internally threaded Luer male connector at the end of the capillary tube of the first multi-channel syringe pump to the eighth two-way valve on the injection needle of the brown reaction bottle. Open the eighth two-way valve and use the first multi-channel syringe pump to inject the extraction reagent into the brown reaction bottle.

[0037] Once completed, close the valve, disconnect all connections, and remove the bottle rack for incubation at 30 degrees Celsius in the dark.

[0038] Furthermore, the first-form absorbent is recovered. The steps for recovering the first-form absorbent include:

[0039] Slowly push the bottle rack into the box from the side opening along the first and second slots, and connect the branch of the first gas splitter and the branch of the second gas splitter to the side and top openings of the second three-way valves of each brown reaction bottle respectively.

[0040] Then close the fifth two-way valve between the lower end of the vacuum gauge and the vacuum pump, rotate the second three-way valve to connect the vacuum gauge to the brown reaction flask, adjust the pressure divider valve connected to the nitrogen cylinder to 0.02 MPa, adjust the gas flow meter flow rate to 50 mL / min, and slowly introduce nitrogen to assist in the extraction of the absorbent and ensure that the brown reaction flask is in an anaerobic state; use the second multi-channel syringe pump connected to the third two-way valve on the liquid exchange needle to extract the absorbent through the liquid exchange needle; then close the nitrogen passage, use the second multi-channel syringe pump to inject the deoxygenated fresh absorbent into the gas absorption cup, and immediately close the third two-way valve;

[0041] Close the sixth two-way valve between the gas flow meter and the first gas splitter, turn on the vacuum pump, and pump out the gas according to the vacuum degree calculated by the aforementioned extraction vacuum degree calculation formula; then use the first multi-channel injection pump to inject the extraction reagent in batches through the liquid exchange needle.

[0042] Furthermore, the extraction conditions for various forms of sulfides in soil include:

[0043] The extraction conditions for volatile sulfuric acid were: 20 mL of 6 mol / L hydrochloric acid and a culture time of 24 hours.

[0044] The extraction conditions for chromium-reduced sulfur were: 20 mL of 1 mol / L chromium chloride and a culture time of 2 days.

[0045] The extraction conditions for elemental sulfur were: 20 mL DMF, 5 mL chromium chloride, and 5 mL concentrated hydrochloric acid, with a culture time of 24 hours.

[0046] Compared with the prior art, the beneficial effects of the continuous extraction device for reducing inorganic sulfides in soil and its usage method in this application embodiment are as follows: In this application embodiment, the brown reaction flask, vacuum pump, and nitrogen source are all connected through a distributor, which allows for batch operation while uniformly controlling reaction conditions such as nitrogen filling rate and vacuum degree; In this application embodiment, the extraction reagent is precisely and batch-injected through the injection needle on the stopper using a multi-channel injection pump, which improves accuracy and efficiency and avoids reagent oxidation; In this application embodiment, the absorbent is replaced under oxygen-isolated conditions using a multi-channel injection pump and a liquid replacement needle, which not only saves the steps of opening the device to replace the absorbent and purging with nitrogen again, but also ensures the airtightness of the device, improves efficiency, and reduces extraction costs.

[0047] In summary, this invention improves the detection efficiency and stability of reducing inorganic sulfides in soil, and provides a good and feasible solution for accurately analyzing the distribution of reducing inorganic sulfides in soil and assessing soil sulfur supply capacity and environmental risks. Attached Figure Description

[0048] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0049] In the attached diagram:

[0050] Figure 1 This is a structural diagram of a continuous extraction device for soil reducing inorganic sulfides according to the present invention;

[0051] Figure 2 for Figure 1 A front view of the provided continuous extraction device;

[0052] Figure 3 for Figure 1 A schematic diagram of the bottle rack structure in the provided continuous extraction device;

[0053] Figure 4 This is a statistical chart showing the changes in the content of volatile sulfur in soil acid over culture time, as extracted in this invention.

[0054] Figure 5 This is a statistical chart showing the changes in the content of volatile sulfur in soil acid with hydrochloric acid concentration, as extracted in this invention.

[0055] Figure 6 This is a statistical chart showing the changes in the content of volatile sulfur in soil acid as a function of hydrochloric acid dosage, as presented in this invention.

[0056] Figure 7 This is a statistical chart showing the changes in soil chromium-reduced sulfur content over culture time, extracted according to the present invention.

[0057] Figure 8 The effect of the extraction reagent of this invention on the elemental sulfur content of soil;

[0058] Figure 9 This is a statistical chart of sulfur recovery rate data under the optimized conditions of this invention;

[0059] Figure 10 This is a statistical chart showing the results of the analysis of reducing inorganic sulfides in soil according to the present invention.

[0060] The above figures include the following reference numerals:

[0061] 1. First slot; 2. Second slot; 3. Bottle rack; 4. Gas absorption cup; 5. First sealing stopper; 6. Reagent deoxygenation bottle; 7. First capillary tube; 8. Second capillary tube; 9. Second sealing stopper; 10. First syringe; 11. Second syringe; 12. Third syringe; 13. First two-way valve; 14. Second two-way valve; 15. First multi-channel syringe pump; 16. First liquid distributor; 17. Absorption liquid deoxygenation bottle; 18. Second liquid distributor; 19. Second multi-channel syringe pump; 20. First three-way valve; 21. Third two-way valve; 22. Chamber; 23. Fourth two-way valve; 24. Lower port of gas flow meter; 25. Gas flow meter; 26. Fifth two-way valve; 27. Lower port of vacuum gauge; 28. Upper port of gas flow meter; 29. ​​Vacuum gauge; 30. Sixth two-way valve; 31. First gas splitter; 32. Upper port of vacuum gauge; 33. Seventh two-way valve; 34. Second gas splitter; 35. Brown reaction flask; 36. Gas replacement needle; 37. Liquid replacement needle; 38. Second three-way valve; 39. Injection needle; 40. Eighth two-way valve; 41. Cylindrical groove; 42. Foam. Detailed Implementation

[0062] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0063] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction of the component itself; similarly, for ease of understanding and description, "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not intended to limit this invention.

[0064] like Figure 1 A continuous extraction device for reducing inorganic sulfides in soil is provided as an embodiment of the present invention;

[0065] Please refer to Figure 1 In this embodiment of the invention, the provided soil reducing inorganic sulfide continuous extraction device includes a reagent deoxygenation bottle 6, an absorption liquid deoxygenation bottle 17, and a brown reaction bottle 35. A first sealing stopper 5 is provided at the mouth of the brown reaction bottle 35. A gas replacement needle 36, an injection needle 39, and a liquid replacement needle 37 are provided on the first sealing stopper 5.

[0066] The reagent deoxygenation bottle 6 is connected to the injection needle 39 via the first liquid distributor 16 and the first multi-channel injection pump 15.

[0067] The absorbent deoxygenation bottle 17 and the liquid replacement needle 37 are connected by a second liquid distributor 18 and a second multi-channel injection pump 19.

[0068] For further details, please refer to [link / reference]. Figure 1 and Figure 3 In this embodiment, a gas absorption cup 4 is provided at the bottom of the first sealing stopper 5.

[0069] Preferably, in this embodiment of the invention, the needle seat of the gas replacement needle 36 is connected to the second three-way valve 38, the needle seat of the injection needle 39 is connected to the eighth two-way valve 40, and the tips of both the gas replacement needle 36 and the injection needle 39 are connected to capillary tubes, which bypass the gas absorption cup 4 and face the inner wall of the brown reaction bottle 35.

[0070] Furthermore, such as Figure 1 and Figure 2 As shown, in the reagent deoxygenation bottle 6 provided in this embodiment, a second sealing stopper 9 is provided at the bottle mouth of the reagent deoxygenation bottle 6. A first needle tube 10, a second needle tube 11 and a third needle tube 12 are respectively provided on the second sealing stopper 9. A second two-way valve 14 is connected to the needle seat of the second needle tube 11. The second two-way valve 14 is connected to the first liquid distributor 16. The first liquid distributor 16 is connected to the first multi-channel injection pump 15. The channel of the first multi-channel injection pump 15 is connected to the eighth two-way valve 40 on the needle seat of the injection needle 39.

[0071] A first two-way valve 13 is connected to the needle seat of the first needle tube 10. The upper port of the two-way valve 13 is connected to a nitrogen supply device, and the nitrogen flow rate is adjusted to deoxygenate the extraction reagent at a flow rate of two bubbles per second.

[0072] The tip of the first needle tube 10 is connected to the second capillary tube 8, and the tip of the second needle tube 11 is connected to the first capillary tube 7.

[0073] Similarly, in this embodiment, the mouth of the absorbent deoxygenation bottle 17 is also provided with a sealing plug, and is connected to the second liquid distributor 18 through the needle tube at the sealing plug and the two-way valve on the needle seat. The second liquid distributor 18 is connected to the second multi-channel injection pump 19, and the channel of the second multi-channel injection pump 19 is connected to the third two-way valve 21 on the needle seat of the liquid replacement needle 37.

[0074] Among them, such as Figure 1 and Figure 3 As shown, in this embodiment, the continuous extraction device for soil reducing inorganic sulfides further includes a box 22. The box 22 is equipped with a removable bottle rack 3. The bottle rack 3 is an open groove structure. Foam 42 is embedded in the open groove. Multiple cylindrical grooves 41 are distributed on the foam 42. The cylindrical grooves 41 are used to fix and place the brown reaction bottle 35.

[0075] Furthermore, the bottom surface of the bottle rack 3 is provided with a first slot 1 and a second slot 2. The first slot 1 and the second slot 2 cooperate with the locking block on the bottom surface of the box 22 to lock and fix the bottle rack 3 inside the box 22.

[0076] Furthermore, the first multi-channel injection pump 15, the first liquid distributor 16, the second liquid distributor 18, and the second multi-channel injection pump 19 provided in this embodiment are all supported and fixedly installed on the outer wall of the housing 22; wherein, the first multi-channel injection pump 15 and the second multi-channel injection pump 19 are vertically fixed on the outer wall of the housing 22, and the first multi-channel injection pump 15 and the second multi-channel injection pump 19 are independent of each other, so as to realize the precise control of gas and the timed and quantitative replacement of absorbent liquid during the reaction process.

[0077] Please continue to refer to Figures 1-3 The continuous extraction device for soil reducing inorganic sulfides provided in this embodiment of the invention also includes a gas flow meter 25 and a vacuum gauge 29;

[0078] Among them, one end of the gas flow meter 25 is sequentially connected to the lower port 24 of the gas flow meter and the fourth two-way valve 23, and the fourth two-way valve 23 is connected to the nitrogen source.

[0079] The other end of the gas flow meter 25 is connected to the first gas splitter 31 via the gas flow meter upper port 28 and the sixth two-way valve 30.

[0080] The branch port of the first gas splitter 31 is connected to the second three-way valve 38 on the seat of the gas replacement needle 36 via a pipeline;

[0081] Furthermore, one end of the vacuum gauge 29 is connected in sequence to the lower port 27 of the vacuum gauge and the fifth two-way valve 26, and the fifth two-way valve 26 is connected to the vacuum pump; the other end of the vacuum gauge 29 is connected to the second gas distributor 34 through the upper port 32 of the vacuum gauge and the seventh two-way valve 33; the distribution port of the second gas distributor 34 is connected to the second three-way valve 38 on the needle seat of the gas replacement needle 36 through a pipeline.

[0082] Furthermore, in this embodiment, the brown reaction bottle 35 on the bottle rack 3 is connected in parallel via a first gas splitter 31 and a second gas splitter 34.

[0083] In this embodiment, the vacuum level of the brown reaction flask 35 and the reagent injection rate are precisely controlled by the vacuum gauge 29 and the first multi-channel injection pump 15 before the reaction.

[0084] Each channel of the first multi-channel injection pump 15 and the second multi-channel injection pump 19 is equipped with a first three-way valve 20, which is connected to the pipeline leading out of the liquid distributor.

[0085] Specifically, the three-way valve port of the first multi-channel injection pump 15 is connected to the first liquid distributor 16; the three-way valve port of the second multi-channel injection pump 19 is connected to the second liquid distributor 18.

[0086] Preferably, the capillary material provided in this embodiment is polytetrafluoroethylene.

[0087] Preferably, both the three-way valve and the two-way valve provided in this embodiment are made of polypropylene; the three-way valve provided in this embodiment includes a first three-way valve 20 and a second three-way valve 38;

[0088] As a preferred embodiment, the two-way valve provided includes a first two-way valve 13, a second two-way valve 14, a third two-way valve 21, a fourth two-way valve 23, a fifth two-way valve 26, a sixth two-way valve 30, a seventh two-way valve 33, and an eighth two-way valve 40.

[0089] In another embodiment of this application, a method of using a continuous extraction device for soil reducing inorganic sulfides is provided, comprising the following steps:

[0090] Step S101: Perform an airtightness check on the extraction device;

[0091] Step S102: Weighing the sample and adding the absorption solution;

[0092] Step S103: Gas replacement to remove air from the brown reaction flask;

[0093] Step S104: Calculate the vacuum level and inject the corresponding sulfur form extraction reagent into the brown reaction flask;

[0094] Step S105: Remove bottle rack 3 and incubate it at 30 degrees Celsius in the dark;

[0095] Step S106: After the culture is completed, the absorption liquid is replaced by using a gas flow meter 25 in conjunction with a second multi-channel injection pump 19 to complete the extraction of the first form of sulfide.

[0096] The step of replacing the absorbent includes: under the condition that nitrogen gas is slowly introduced into the side port of the second three-way valve 38 (in order to increase the bottle pressure and prevent air from entering), the absorbent in the gas absorption cup 4 is extracted in batches by the second multi-channel injection pump 19, and then the nitrogen gas passage is closed, and the new absorbent after deoxygenation is slowly injected into the gas absorption cup 4 through the second multi-channel injection pump 19 and the third two-way valve 21.

[0097] Step S107: Repeat steps S104-S106 in sequence to extract the second form of sulfide and the third form of sulfide. In step S106, the third form of sulfide is extracted only by the absorption liquid. Gas replacement is not repeated in the whole process.

[0098] Step S108: Calculate the content of different forms of reduced inorganic sulfides in the soil based on the sulfide concentration in the absorbent.

[0099] Furthermore, in step S101 provided in this embodiment, the airtightness of the extraction device is checked by any of the following methods: using a gas flow meter 25 for auxiliary inspection and using a vacuum gauge to check the airtightness of the device.

[0100] In the auxiliary inspection using the gas flow meter 25 provided in this embodiment, the nitrogen source, gas flow meter 25, first gas distributor 31 and brown reaction bottle 35 are connected in sequence, and the other valves are closed; the nitrogen source is turned on, the pressure value is set to 0.02MPa, and the flow rate of the gas flow meter 25 is adjusted to 100mL / min. When the rotor of the gas flow meter 25 can return to the 0 mark again, it proves that the device has good airtightness.

[0101] In this embodiment, the airtightness of the device using vacuum gauge 29 is checked by sequentially connecting vacuum gauge 29, second gas distributor 34, and brown reaction bottle 35 via a three-way valve, while closing the other valves; turning on the vacuum pump to draw the vacuum to a fixed value, closing the seventh two-way valve 33 between the vacuum pump and vacuum gauge 29, and judging the airtightness of the device based on the drop of the pointer of vacuum gauge 29.

[0102] Furthermore, in step S102 of this embodiment, after the sample is weighed, the first form of sulfur extraction and absorption liquid is added to the gas absorption cup 4 and then the first sealing stopper 5 is tightened; the brown reaction bottle 35 is placed in the cylindrical groove 41 and fixed, and the bottle rack 3 is slowly pushed into the box 22 from the side opening of the box 22 along the first slot 1 and the second slot 2, and the branch of the first gas splitter 31 and the branch of the second gas splitter 34 of the vacuum pump are respectively connected to the side opening and the top opening of the second three-way valve 38 of each brown reaction bottle 35, and the straight port of the three-way valve on the first multi-channel injection pump 15 is connected to the eighth two-way valve 40 of the brown reaction bottle 35.

[0103] Furthermore, in step S103 of this embodiment, after three cycles of gas replacement, the pressure of the brown reaction bottle 35 is pumped to the pressure calculated by the formula according to the amount of reagent injected and the final required bottle pressure. Then, the reagent is injected into the brown reaction bottle 35 through the injection needle 39 using the first multi-channel injection pump 15.

[0104] Furthermore, in step S104, the formula for calculating the vacuum level is:

[0105]

[0106]

[0107] In the formula, This represents the total volume of reagent injected in the first n injections; This represents the volume of reagent injected in the i-th injection; P represents the bottle pressure after vacuuming; P represents the target bottle pressure after reagent injection. Indicates the initial volume of the reaction flask; This represents the total volume of the first n-1 injections;

[0108] In this embodiment, the gauge pressure is utilized The atmospheric pressure is calculated by subtracting atmospheric pressure, which is calculated as 0.1 MPa.

[0109] Furthermore, in this embodiment, before gas replacement, the nitrogen source pressure is adjusted to 0.02 MPa, and the flow rate of the gas flow meter 25 is adjusted to 100 mL per minute. Then, the sixth two-way valve 30 between the gas flow meter 25 and the first gas distributor 31 is closed, and the vacuum pump is turned on to evacuate to -0.095 MPa. Subsequently, the fifth two-way valve 26 between the vacuum pump and the vacuum gauge 29 is closed, and the sixth two-way valve 30 between the gas flow meter 25 and the first gas distributor 31 is opened to begin nitrogen charging. After the rotor of the gas flow meter 25 returns to the 0 mark, the sixth two-way valve 30 between the gas flow meter 25 and the first gas distributor 31 is closed after 1 minute. The vacuum pump and the fifth two-way valve 26 are then turned on again for a second vacuum evacuation; thus completing the gas replacement process.

[0110] After performing the above gas replacement process for 3 cycles, the brown reaction bottle 35 is evacuated to the vacuum level calculated by the formula according to the amount of injected extract, and the second three-way valve 38 is closed.

[0111] Furthermore, in step S104, the step of injecting the corresponding extraction reagent into the brown reaction flask 35 according to the extracted sulfur form in this embodiment of the application includes:

[0112] Install the corresponding number of syringe pumps on the first multi-channel syringe pump 15 and debug it. Connect the side port of the three-way valve connected to the multi-channel syringe pump 15 to the two-way valve 14 on the reagent deoxygenation bottle 6. The capillary tube on the second needle tube 11 connected to the two-way valve 14 needs to be inserted below the surface of the extracted reagent liquid.

[0113] Operate the first multi-channel syringe pump 15 to extract the extraction reagent, rotate the valve of the first three-way valve 20 corresponding to the first multi-channel syringe pump 15 to close the side port connection, and then operate the first multi-channel syringe pump 15 to purge the air in the capillary tube between the first multi-channel syringe pump 15 and the eighth two-way valve 40.

[0114] Connect the threaded Luer male connector on the end of the capillary tube connected to the straight port of the three-way valve of the multi-channel injection pump 15 to the eighth two-way valve 40 on the injection needle 39 of the brown reaction bottle 35; open the eighth two-way valve 40 and inject the extraction reagent into the brown reaction bottle 35 using the first multi-channel injection pump 15; after completion, close the valve, disconnect all connections, remove the bottle rack 3 and incubate it at 30 degrees Celsius in the dark for 24 hours to obtain the first form of sulfide absorption solution.

[0115] Furthermore, the first form of absorbent is recovered, wherein the first form of absorbent (absorbent containing acidic volatile sulfur) is obtained by adding extraction reagent (6 mol / L hydrochloric acid) in step S104 and culturing for 24 hours in step S105.

[0116] The logical relationship between the recovered absorbent and the extracted sulfide forms is as follows:

[0117] First form of absorbent (absorbent containing acidic volatile sulfur): 6 mol / L hydrochloric acid is added to the soil, which volatilizes hydrogen sulfide gas, and the absorbent fixes the volatilized hydrogen sulfide. Second form of absorbent (absorbent containing chromium-reduced sulfur): 1 mol / L chromium chloride is added to the soil, which volatilizes hydrogen sulfide gas, and the absorbent fixes the volatilized hydrogen sulfide. Third form of absorbent (absorbent containing elemental sulfur): mainly obtained by adding DMF to the soil, which volatilizes hydrogen sulfide and fixes it in the absorbent.

[0118] Specifically, the steps for recovering the first-form absorbent in this embodiment include:

[0119] Slowly push the bottle rack 3 into the box 22 from the side opening of the box 22 along the first slot 1 and the second slot 2, and connect the branch of the first gas splitter 31 and the branch of the second gas splitter 34 to the side opening and the top opening of the second three-way valve 38 of each brown reaction bottle 35 respectively.

[0120] Subsequently, close the fifth two-way valve 26 between the lower port 27 of the vacuum gauge and the vacuum pump, rotate the second three-way valve 38 to connect the vacuum gauge 29 to the brown reaction bottle 35, adjust the pressure valve connected to the nitrogen cylinder to 0.02MPa, adjust the flow rate of the gas flow meter to 50mL / min and slowly introduce nitrogen to assist in the extraction of the absorbent and ensure that the brown reaction bottle 35 is in an anaerobic state; use the second multi-channel syringe pump 19 to connect to the third two-way valve 21 on the liquid exchange needle 37 to extract the absorbent through the liquid exchange needle 37; then close the nitrogen passage, use the second multi-channel syringe pump 19 to inject the deoxygenated fresh absorbent into the gas absorption cup 4, and immediately close the valve of the third two-way valve 21;

[0121] Close the sixth two-way valve 30 between the gas flow meter 25 and the first gas splitter 31, turn on the vacuum pump, and pump out the gas according to the vacuum degree calculated by the aforementioned extraction vacuum degree calculation formula; then use the first multi-channel injection pump 15 to inject the extraction reagent in batches through the liquid exchange needle 37.

[0122] Similarly, the extraction steps for the third form of sulfide are the same as those for the second form of sulfide. However, in step S106, the extraction of the third form of sulfide only requires the extraction of the absorbent liquid to end the experiment, without the need to inject new absorbent liquid.

[0123] In addition, gas replacement is required before injecting the first form of sulfide extraction reagent, while the second and third forms of sulfide can be injected after changing the absorbent; furthermore, the absorbent for the first form of sulfide is added first and then the stopper is closed, without using a multi-channel syringe pump to add the absorbent.

[0124] In this embodiment, the first form of sulfide is acid-volatile sulfur; the second form of sulfide is chromium-reduced sulfur; and the third form of sulfide is elemental sulfur.

[0125] Furthermore, the sulfide content in the absorption liquid was determined by methylene blue spectrophotometry, and the content of different forms of reduced inorganic sulfides in the soil was calculated based on the sulfide concentration in the absorption liquid.

[0126] The formulas for calculating various forms of reduced inorganic sulfides in soil are as follows:

[0127]

[0128] In the formula, W represents the content of soil reduced inorganic sulfur in the measured form; C represents the sulfur concentration calculated by substituting the true absorbance into the standard curve using the methylene blue spectrophotometric method; V1 represents the colorimetric volume; V2 represents the volume of the absorption liquid used during extraction; m represents the weight of the soil used for extraction; K represents the soil moisture content; and V3 represents the volume of the absorption liquid used for measurement.

[0129] According to one embodiment of this application:

[0130] Figure 4 The following is a statistical chart showing the change in the content of volatile sulfur in soil extracted by the continuous extraction device of the present invention with the incubation time; for example... Figure 4As shown in the embodiment of this invention, in the method for extracting acidic volatile sulfur from paddy soil, five treatments were set for cultivation time: 4h, 8h, 12h, 16h, and 24h. Four treatments were set for hydrochloric acid concentration: 1mol / L, 2mol / L, 4mol / L, and 6mol / L. Four treatments were set for hydrochloric acid dosage: soil-to-hydrochloric acid ratios of 1:2, 1:3, 1:4, and 1:5. Each treatment had three replicates. In this embodiment, the sulfide content in the absorption liquid was determined by methylene blue spectrophotometry, and then the acidic volatile sulfur content in the soil was calculated. Figure 4 It can be seen that 24 hours is the optimal incubation time.

[0131] Figure 5 This invention presents a statistical chart showing the variation of volatile sulfur content in soil extracted by the continuous extraction device as a function of hydrochloric acid concentration; (The chart is derived from...) Figure 5 It can be seen that the content of volatile sulfur in the acid was significantly higher when using 6 mol / L hydrochloric acid for extraction than other concentrations.

[0132] Figure 6 This invention presents a statistical chart showing the variation of volatile sulfur content in soil extracted by the continuous extraction device as a function of hydrochloric acid dosage; (The chart is derived from...) Figure 6 It can be seen that when the amount of hydrochloric acid used is 15 mL, the content of volatile sulfur extracted is the highest.

[0133] According to another embodiment of this application:

[0134] Figure 7 This paper presents a statistical chart showing the changes in soil chromium-reduced sulfur content with incubation time using the continuous extraction device of the present invention.

[0135] This embodiment employs the method of the present invention for extracting chromium-reduced sulfur from paddy soil. Three treatments were set up with incubation times of 1 day, 2 days, and 4 days, with three replicates for each treatment. The sulfide content in the absorption liquid was determined using methylene blue spectrophotometry, and then the chromium-reduced sulfur content in the soil was calculated. Figure 7 Therefore, the recommended culture time in this embodiment is set to 2 days.

[0136] According to yet another embodiment of this application:

[0137] Figure 8 The effect of the extraction reagents in the continuous extraction apparatus of the present invention on the elemental sulfur content of the soil is shown.

[0138] This embodiment uses the extraction method of elemental sulfur in paddy soil according to the present invention, and four treatments are set up for the extraction reagents:

[0139] Treatment 1: Add 20 mL of DMF;

[0140] Treatment 2 involves adding 20 mL of DMF and 5 mL of chromium chloride.

[0141] Treatment 3 is as follows: Add 20 mL of DMF, 5 mL of chromium chloride, and 5 mL of 6 mol / L hydrochloric acid;

[0142] Treatment 4: Add 20 mL of DMF, 5 mL of chromium chloride, and 5 mL of concentrated hydrochloric acid;

[0143] For the four processes mentioned above, each process is set to have 3 repetitions.

[0144] This embodiment uses the methylene blue spectrophotometric method to determine the sulfide content in the absorption liquid, and then calculates the elemental sulfur content of the soil. Figure 8 It is known that the extraction efficiency is higher when chromium chloride and concentrated hydrochloric acid are added on the basis of adding 20 mL DMF than other treatments. Therefore, this embodiment of the invention recommends the use of DMF, chromium chloride and concentrated hydrochloric acid in combination for the extraction of elemental sulfur from soil.

[0145] According to another embodiment of this application:

[0146] Figure 9 A statistical chart showing the sulfur recovery rate under optimized conditions of the continuous extraction device of the present invention is shown.

[0147] This embodiment uses the continuous extraction device of the present invention to conduct a sulfur recovery rate test. Five gradient treatments with sulfur contents of 10ug, 20ug, 30ug, 40ug, and 50ug were set, and the extraction conditions were the optimal conditions described in the previous embodiment. Each treatment was repeated in triplicate. After each treatment was cultured, the sulfide content in the absorption liquid was determined by methylene blue spectrophotometry, and the sulfur recovery rate was then calculated. Figure 9 It can be seen that the recovery rates of sulfides in each parallel group are stable, indicating that the batch continuous extraction device provided by the present invention has high stability.

[0148] According to another embodiment of this application:

[0149] Figure 10 A statistical chart of the results for reducing inorganic sulfides in this invention is shown;

[0150] This embodiment uses the continuous extraction device of the present invention to analyze the content of reducing sulfides in paddy soil;

[0151] The extraction conditions for volatile sulfuric acid were: 20 mL of 6 mol / L hydrochloric acid and a culture time of 24 hours.

[0152] The extraction conditions for chromium-reduced sulfur were: 20 mL of 1 mol / L chromium chloride and a culture time of 2 days.

[0153] The extraction conditions for elemental sulfur were: 20 mL DMF, 5 mL chromium chloride, and 5 mL concentrated hydrochloric acid, with a culture time of 24 hours.

[0154] In summary, through verification of various embodiments, it can be seen that the present invention constructs an efficient reaction process model. By controlling reaction conditions, such as gas flow rate, pressure inside the reaction flask, reaction temperature, and time, which affect the reaction rate, the gas diffusion conditions are optimized, thereby improving extraction efficiency and recovery rate.

[0155] The above solutions are merely illustrative examples of preferred embodiments and are not intended to limit the scope of the invention. Appropriate substitutions and / or modifications can be made according to user needs when implementing this invention.

[0156] The number of devices and processing scale described herein are for the purpose of simplifying the description of the invention. Applications, modifications, and variations of the invention will be readily apparent to those skilled in the art.

[0157] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. It can be applied to various fields suitable for the present invention. Other modifications can be readily made by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and examples shown and described herein.

Claims

1. A continuous extraction device for soil reducing inorganic sulfides, characterized in that, include: A brown reaction bottle (35) is provided with a first sealing stopper (5) at the mouth of the brown reaction bottle (35). The first sealing stopper (5) is provided with a gas replacement needle (36), an injection needle (39) and a liquid replacement needle (37); a gas absorption cup (4) is also provided at the bottom of the first sealing stopper (5). A reagent deoxygenation bottle (6) is connected to the injection needle (39) via a first liquid splitter (16) and a first multi-channel injection pump (15). A second sealing stopper (9) is provided at the bottle mouth of the reagent deoxygenation bottle (6). A first needle tube (10), a second needle tube (11) and a third needle tube (12) are respectively provided on the second sealing stopper (9). A second two-way valve (14) is connected to the needle seat of the second needle tube (11). The second two-way valve (14) is connected to the first liquid splitter (16). The first liquid splitter (16) is connected to the first multi-channel injection pump (15). The channel of the first multi-channel injection pump (15) is connected to the eighth two-way valve (40) on the needle seat of the injection needle (39). The absorbent deoxygenation bottle (17) is connected to the liquid replacement needle (37) via a second liquid distributor (18) and a second multi-channel injection pump (19). The bottle mouth of the absorbent deoxygenation bottle (17) is also equipped with a sealing plug, and is connected to the second liquid distributor (18) via the needle tube at the sealing plug and the two-way valve on the needle seat. The second liquid distributor (18) is connected to the second multi-channel injection pump (19), and the channel of the second multi-channel injection pump (19) is connected to the third two-way valve (21) on the needle seat of the liquid replacement needle (37).

2. The continuous extraction device for soil reducing inorganic sulfides according to claim 1, characterized in that, It also includes a gas flow meter (25), one end of which is connected to a gas flow meter lower port (24) and a fourth two-way valve (23), and the fourth two-way valve (23) is connected to a nitrogen source; The other end of the gas flow meter (25) is connected to the first gas splitter (31) through the gas flow meter upper port (28) and the sixth two-way valve (30); the split port of the first gas splitter (31) is connected to the second three-way valve (38) on the needle seat of the gas replacement needle (36) through a pipeline.

3. The continuous extraction device for soil reducing inorganic sulfides according to claim 2, characterized in that, It also includes a vacuum gauge (29), one end of which is connected to the lower port (27) of the vacuum gauge and the fifth two-way valve (26) in sequence, and the fifth two-way valve (26) is connected to the vacuum pump; the other end of the vacuum gauge (29) is connected to the second gas distributor (34) through the upper port (32) of the vacuum gauge and the seventh two-way valve (33); the distribution port of the second gas distributor (34) is connected to the second three-way valve (38) on the needle seat of the gas replacement needle (36) through a pipeline.

4. The continuous extraction device for soil reducing inorganic sulfides according to claim 2, characterized in that, The tips of the gas replacement needle (36) and the injection needle (39) are both connected to capillary tubes, which bypass the gas absorption cup (4) and face the inner wall of the brown reaction bottle (35). The tip of the first needle tube (10) is connected to the second capillary tube (8), and the tip of the second needle tube (11) is connected to the first capillary tube (7). The three-way valve side port of the first multi-channel injection pump (15) is connected to the first liquid distributor (16); The three-way valve side port of the second multi-channel injection pump (19) is connected to the second liquid distributor (18).

5. A method of using a continuous extraction device for soil reducing inorganic sulfides according to any one of claims 1 to 4, characterized in that, Includes the following steps: Step S101: Perform an airtightness check on the extraction device; Step S102: Weighing the sample and adding the absorption solution; Step S103: Gas replacement to remove air from the brown reaction flask; Step S104: Calculate the vacuum level and inject the corresponding sulfur form extraction reagent into the brown reaction flask; Step S105: Remove the bottle rack (3) and incubate it in the dark at 30 degrees Celsius; Step S106: After the culture is completed, the absorption liquid is replaced by using a gas flow meter (25) in conjunction with a second multi-channel injection pump (19) to complete the extraction of the first form of sulfide; Step S107: Repeat steps S104-S106 in sequence to extract the second form of sulfide and the third form of sulfide. In step S106, the third form of sulfide is extracted only by the absorption liquid. Gas replacement is not repeated in the whole process. Step S108: Calculate the content of different forms of reduced inorganic sulfides in the soil based on the sulfide concentration in the absorbent.

6. The method of use according to claim 5, characterized in that, Before the gas replacement in step S103, the nitrogen source pressure is adjusted to 0.02MPa and the flow rate of the gas flow meter (25) is adjusted to 100mL per minute. During gas replacement, close the sixth two-way valve (30) between the gas flow meter (25) and the first gas distributor (31), and turn on the vacuum pump to evacuate the vacuum to -0.095MPa; Subsequently, the fifth two-way valve (26) between the vacuum pump and the vacuum gauge (29) is closed, and the sixth two-way valve (30) between the gas flow meter (25) and the first gas distributor (31) is opened to begin charging nitrogen. After the gas flow meter (25) rotor returns to the 0 mark, close the sixth two-way valve (30) between the gas flow meter (25) and the first gas distributor (31) after 1 minute. Open the vacuum pump and the fifth two-way valve (26) again to perform a second vacuuming and complete the gas replacement process.

7. The method of use according to claim 6, characterized in that, After three cycles of gas replacement, the pressure of the brown reaction bottle (35) is reduced to the pressure calculated by the formula according to the amount of reagent injected and the final required bottle pressure. Then, the reagent is injected into the brown reaction bottle (35) through the injection needle (39) using the first multi-channel injection pump (15). After performing the above gas replacement process for 3 cycles, based on the amount of injected extract, the brown reaction flask (35) is evacuated to the vacuum level calculated by the formula, and the second three-way valve (38) is closed. The formula for calculating the vacuum level is as follows: In the formula, This represents the total volume of reagent injected in the first n injections; This represents the volume of reagent injected in the i-th injection; P represents the vacuum pressure; P represents the target bottle pressure after reagent injection. Indicates the initial volume of the reaction flask; This represents the total volume of the first n-1 injections.

8. The method of use according to claim 7, characterized in that, In step S (104), the step of injecting the corresponding extraction reagent into the brown reaction flask (35) according to the extracted sulfur form includes: Install the corresponding number of syringe pumps on the first multi-channel syringe pump (15) and debug it. Connect the three-way valve side port of the first multi-channel syringe pump (15) to the two-way valve (14) on the reagent deoxygenation bottle (6). Insert the capillary tube (7) connected to the two-way valve (14) below the surface of the extraction reagent liquid. Operate the first multi-channel syringe pump (15) to extract the extraction reagent, rotate the three-way valve corresponding to the first multi-channel syringe pump (15) to close the side port connection, and then operate the first multi-channel syringe pump (15) to vent the air in the capillary tube between the first multi-channel syringe pump (15) and the eighth two-way valve (40); Connect the internally threaded Luer male connector of the first multi-channel injection pump (15) directly to the injection needle (39) of the brown reaction bottle (35) and open the valve of the eighth two-way valve (40). Use the first multi-channel injection pump (15) to inject the extraction reagent into the brown reaction bottle (35). After completion, close the valve, disconnect all connections, remove the bottle rack (3) and place it in a 30-degree Celsius dark environment for incubation.

9. The method of use according to claim 8, characterized in that, The recovery of the first-form absorbent includes the following steps: Slowly push the bottle rack (3) into the box (22) from the side opening of the box (22) along the first slot (1) and the second slot (2), and connect the branch of the first gas splitter (31) and the branch of the second gas splitter (34) to the side opening and top opening of the second three-way valve (38) of each brown reaction bottle (35); Then close the fifth two-way valve (26) between the lower port (27) of the vacuum gauge and the vacuum pump, rotate the second three-way valve (38) to connect the vacuum gauge (29) with the brown reaction bottle (35), adjust the pressure valve connected to the nitrogen cylinder to 0.02MPa, adjust the flow rate of the gas flow meter to 50mL / min, and slowly introduce nitrogen to assist in the extraction of the absorbent and ensure that the brown reaction bottle (35) is in an anaerobic state; use the second multi-channel syringe pump (19) to connect the third two-way valve (21) on the liquid exchange needle (37) to extract the absorbent through the liquid exchange needle (37); Subsequently, the nitrogen passage was closed, and the freshly prepared absorbent after deoxygenation was injected into the gas absorption cup (4) using the second multi-channel injection pump (19), and the valve of the third two-way valve (21) was immediately closed. Close the sixth two-way valve (30) between the gas flow meter (25) and the first gas splitter (31), and turn on the vacuum pump; The calculated vacuum level is used for evacuation; then the extraction reagent is injected in batches through the first multi-channel injection pump (15) and the liquid exchange needle (37).

10. The continuous extraction device for soil reducing inorganic sulfides and its method of use according to claim 9, characterized in that, Extraction conditions for various forms of sulfides in soil include: The extraction conditions for volatile sulfuric acid were: 20 mL of 6 mol / L hydrochloric acid and a culture time of 24 hours. The extraction conditions for chromium-reduced sulfur were: 20 mL of 1 mol / L chromium chloride and a culture time of 2 days. The extraction conditions for elemental sulfur were: 20 mL DMF, 5 mL chromium chloride, and 5 mL concentrated hydrochloric acid, with a culture time of 24 hours.

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