阅读说明：本技术 土壤有机碳矿化co2释放量连续测定装置及方法 (Mineralization of CO by organic carbon in soil2Device and method for continuously measuring release amount ) 是由 戴伟 肖永丽 栾亚宁 周鑫 于 2020-07-24 设计创作，主要内容包括：本发明公开了一种土壤有机碳矿化CO<Sub>2</Sub>释放量连续测定装置及方法,在土壤矿化培养前向土壤矿化培养瓶中通入无CO<Sub>2</Sub>空气,再对矿化培养瓶中的土壤进行培养,利用CO<Sub>2</Sub>吸收瓶对矿化培养瓶释放的CO<Sub>2</Sub>气体进行吸收滴定,然后再进行土壤有机碳矿化CO<Sub>2</Sub>释放量的测定,本发明中土壤有机碳矿化过程中CO<Sub>2</Sub>释放量测定方法能够确保氧气和水分条件始终一致,长期,连续,有效地对土壤有机碳矿化过程中CO<Sub>2</Sub>释放量进行测定,且极大减少工作量。(The invention discloses a method for mineralizing CO by using organic carbon in soil 2 The continuous measurement device and method of release amount comprises introducing CO-free gas into a soil mineralization culture bottle before soil mineralization culture 2 Air, culturing the soil in mineralized culture bottle, and using CO 2 Absorbing CO released by the bottle to the mineralized culture bottle 2 Absorbing and titrating the gas, and mineralizing the CO by the organic carbon in the soil 2 Measurement of released amount, in the invention, CO is generated in the process of mineralizing organic carbon in soil 2 The method for measuring the release amount can ensure that the oxygen and water conditions are consistent all the time, and the method can continuously and effectively mineralize CO in the organic carbon mineralization process of the soil for a long time 2 The release amount is measured, and the workload is greatly reduced.)

1. Organic carbon mineralized CO in soil₂A continuous measurement device for a released amount, characterized in that: including no CO₂Air production device, mineralization culture device, and CO₂An absorption calculation device;

said CO-free₂The air producing device comprises an air pump and no CO₂Air making bottle, said CO-free₂NaOH solution is filled in the air making bottle;

the mineralization culture device comprises a mineralization culture bottle, and a soil sample is filled in the mineralization culture bottle;

the CO is₂Absorption calculating means comprising CO₂An absorption bottle, an automatic titration and calculation device, the CO₂NaOH solution is filled in the absorption bottle;

the air pump is connected with the air pump through an air vent pipelineNo CO₂Air making bottle connected, said CO-free₂The air making bottle is connected with the mineralization culture bottle through an air pipeline, and the mineralization culture bottle is connected with CO through the air pipeline₂The absorption bottles are connected; from said CO-free₂The gas from the air making bottle to the mineralizing culture bottle has no CO₂(ii) a Leading to CO from the mineralization culture flask₂The gas in the absorption bottle contains CO₂；

The automatic titration and calculation device comprises an indicator feeder, an HCl titrator, a color sensor, a controller, and an automatic calculation and recording device, wherein phenolphthalein and BaCl are stored in the indicator feeder₂The HCl titrator is internally stored with HCl standard liquid, the controller is used for controlling the actions of the indicator feeder, the HCl titrator and the color sensor, and the automatic calculating and recording device is used for calculating the CO according to the HCl standard liquid₂Calculating the amount of NaOH solution in the absorption bottle to release CO in soil within a certain mineralization time period₂And recording and storing.

2. Soil organic carbon mineralization CO according to claim 1₂A continuous measurement device for a released amount, characterized in that: said CO-free₂The air production device also comprises CO₂Detecting the first component, CO₂The first detection bottle is filled with Ca (OH)₂A solution; said CO-free₂The air making bottle is communicated with CO through an air vent pipeline₂The detection bottle is connected with the CO₂The detection bottle is connected with the mineralization culture bottle through a ventilation pipeline.

3. Soil organic carbon mineralization CO according to claim 1₂A continuous measurement device for a released amount, characterized in that: the mineralization culture device further comprises a soil moisture monitor, a soil moisture sensor and an automatic moisture supplement device, wherein the soil moisture sensor monitors the water content of the soil sample, and the soil moisture monitor controls the automatic moisture supplement device to supplement water into the mineralization culture bottle according to the water content of the soil sample.

4. According to claimMineralization of CO by organic carbon in soil as described in claim 1₂A continuous measurement device for a released amount, characterized in that: the CO is₂The absorption calculating device also comprises CO₂Detecting the second bottle, CO₂The second detection bottle is filled with Ca (OH)₂Solution of said CO₂The two ends of the detection bottle pass through a vent pipeline and the CO₂The absorption bottles are connected.

5. Soil organic carbon mineralization CO according to claim 1 or 2 or 4₂A continuous measurement device for a released amount, characterized in that: each air pipeline is provided with a one-way valve; and in the mineralization culture flask and CO₂The air blocking clamp is arranged on the air vent pipeline between the absorption bottles.

6. Organic carbon mineralized CO in soil₂A method for continuously measuring a released amount, characterized by comprising the steps of:

1) in advance without CO₂Filling NaOH solution into an air making bottle, filling a soil sample into a mineralization culture bottle, and filling CO into the mineralization culture bottle₂Filling NaOH solution into the absorption bottle;

2) to no CO₂Introducing air into the air making bottle, wherein the CO is not contained₂Making CO-free in air making bottle₂Air, simultaneously opened from said CO-free₂The air making bottle is communicated with an air pipeline of the mineralization culture bottle;

3) continuously introducing CO-free into the mineralization culture bottle₂After a period of time in the air, the reaction is stopped to CO-free₂Introducing air into the air making bottle, and then opening the mineralized culture bottle to lead CO₂Vent line of absorption bottle simultaneously to said CO₂Phenolphthalein and BaCl are dripped into an absorption bottle₂A solution;

4) when the CO is present₂When the amount of white precipitate generated in the absorption bottle is not changed any more, the CO is added₂Dropwise adding HCl standard solution into an absorption bottle until the solution changes from pink to colorless;

5) calculating the soil organic carbon mineralization culture CO according to the following relational expression₂The release amount of (a):

CO absorption by NaOH₂The chemical reaction formula (II) is as follows:

2NaOH+CO₂＝Na₂CO₃+H₂O (1)

BaCl₂with Na₂CO₃The chemical reaction formula (II) is as follows:

Na₂CO₃+BaCl₂＝NaCl+BaCO₃↓ (2)

HCl titrates the chemical reaction of the remaining NaOH:

NaOH_(remainder)+HCl＝NaCl+H₂O (3)

Setting CO₂The initial concentration of NaOH solution in the absorption flask was C1, volume was V1, and the amount of initial material was n1 ═ C1 × V1;

setting the initial concentration of the HCl standard solution as C2 and the volume as V2, and the residual volume after titration as V3, wherein the amount of HCl substances consumed by titration is n2 ═ C2 ═ V2-V3;

then CO₂The amount of the residual NaOH substance in the absorption bottle is n 2;

then absorb CO₂The amount of NaOH consumed was n3 ═ n1-n 2;

the organic carbon in the soil mineralizes CO₂The released amount of (a) is M ═ (n1-n2) × M/2;

m is CO₂Molar mass of (a).

7. Soil organic carbon mineralization CO according to claim 6₂The continuous measurement method for the release amount is characterized in that the water content of the soil sample is kept within a set range.

8. Soil organic carbon mineralization CO according to claim 7₂The continuous determination method of the release amount is characterized in that the actually measured water content of the soil sample is obtained by adopting a multipoint measurement and averaging method; and when the actually measured water content is smaller than the required water content and the difference value between the actually measured water content and the required water content is larger than the threshold value, water is required to be supplemented.

9. The continuous release of soil organic carbon mineralized CO2 according to claim 6The determination method is characterized in that the CO is not contained₂Air making bottle connection CO₂Detecting bottle one, no CO₂Air passing through the CO₂The first detection bottle is introduced into the mineralization culture bottle, and the CO is₂The first detection bottle is filled with clarified Ca (OH)₂Solution of when said Ca (OH)₂And stopping the ventilation of the mineralization culture bottle when the solution is turbid.

10. The method for continuously measuring the release of CO2 mineralized by organic carbon in soil according to claim 6, wherein the CO is released from the soil₂The absorption bottle is connected with CO₂A second detection bottle consisting of the said CO₂Introducing the gas discharged from the absorption bottle into the CO₂Detecting the second bottle; the CO is₂The second detection bottle is filled with clear Ca (OH)₂Solution of when said Ca (OH)₂Stopping the flow of the mineralized culture bottle to CO immediately when the solution is turbid₂Introducing gas into the absorption bottle to replace CO₂The aeration is continued after the absorption bottle.

Technical Field

The invention relates to CO in soil₂The method for measuring the release amount of CO in the mineralization of organic carbon₂A device and a method for continuously measuring a released amount.

Background

The global soil carbon reservoir was found to be about 2500Gt, where soil organic carbon is the predominant form of soil carbon reservoir, which has a reserve of about 1550 Gt. The soil organic carbon mineralization is that soil microorganisms decompose soil organic carbon under aerobic conditions to complete self metabolism and release CO₂、H₂The O process and the mineralization measurement of soil organic carbon have important significance for understanding and grasping carbon conversion and soil microorganism activities in soil.

At present, the method for measuring the mineralization of organic carbon in soil mostly adopts an indoor alkali liquor absorption measurement method. The method generally comprises the steps of placing a certain amount of soil sample in a culture bottle, adjusting the water content of the soil to 60% of the saturated water content, placing an absorption bottle containing sodium hydroxide solution with certain concentration and volume in the culture bottle, culturing for a certain time under the constant temperature condition, taking out the absorption bottle, titrating the sodium hydroxide solution in the absorption bottle by using hydrochloric acid solution with known concentration, and calculating to obtain CO released by the soil sample₂Amount of the compound (A). However, the above-mentioned determination method has certain defects, thereby affecting the accuracy of experimental data, which is mainly expressed in that:

first, if the mineralization culture is carried out for a long time in a completely closed condition using a culture flask, O may be caused in the culture flask at a later stage of the culture due to consumption of activity of microorganisms₂Insufficient or even anaerobic conditions occur, so that the mineralization conditions are inconsistent at different culture time stages, and the accuracy of the result is influenced;

secondly, if the culture is carried out for a long time under the condition of incomplete sealing, although the supply of oxygen in the culture process can be ensured, the evaporation and the dissipation of soil moisture can occur, the moisture conditions before and after mineralization are changed, and meanwhile, CO in the outside air can also be caused₂CO produced by admission or mineralization processes₂The liquid diffuses out of the absorption bottle, so that the accuracy of the result is influenced;

third, continuous measurement cannot be performed. In order to deeply understand the characteristics of organic carbon mineralization of soil, the acquisition of CO under different mineralization times is often required₂Continuous data of release amount. Under the current test conditions, the equivalent sample can be weighed only by multiple timesThe method not only increases the possibility of test errors, for example, sample weighing errors and culture errors generated by sample weighing and culture for many times, thereby influencing the accuracy of a measuring result, but also has the defects of complicated measuring steps, inconvenient operation, large test workload and the like.

Disclosure of Invention

In order to overcome the defects in the determination technology, the invention provides CO in the soil organic carbon mineralization process₂A device and a method for continuously measuring a released amount. The measuring device ensures the air tightness of the gas in the whole process and the accuracy of the reagent amount, the measuring method can reduce the test error possibly generated by sample weighing and culturing for many times in the test, improve the accuracy of data, greatly simplify the measuring steps and effectively reduce the workload.

The technical scheme provided by the invention is as follows: organic carbon mineralized CO in soil₂Continuous measurement of released amount, including no CO₂Air production device, mineralization culture device, and CO₂An absorption calculation device;

said CO-free₂The air producing device comprises an air pump and no CO₂Air making bottle, said CO-free₂NaOH solution is filled in the air making bottle;

the mineralization culture device comprises a mineralization culture bottle, and a soil sample is filled in the mineralization culture bottle;

the CO is₂Absorption calculating means comprising CO₂An absorption bottle, an automatic titration and calculation device, the CO₂NaOH solution is filled in the absorption bottle;

the air pump is connected with the CO-free air pump through an air vent pipeline₂Air making bottle connected, said CO-free₂The air making bottle is connected with the mineralization culture bottle through an air pipeline, and the mineralization culture bottle is connected with CO through the air pipeline₂The absorption bottles are connected; from said CO-free₂The gas from the air making bottle to the mineralizing culture bottle has no CO₂(ii) a Leading to CO from the mineralization culture flask₂The gas in the absorption bottle contains CO₂；

The automatic titration and calculation device comprises an indicator feeder, an HCl titrator, a color sensor, a controller, and an automatic calculation and recording device, wherein phenolphthalein and BaCl are stored in the indicator feeder₂The HCl titrator is internally stored with HCl standard liquid, the controller is used for controlling the actions of the indicator feeder, the HCl titrator and the color sensor, and the automatic calculating and recording device is used for calculating the CO according to the HCl standard liquid₂Calculating the amount of NaOH solution in the absorption bottle to release CO in soil within a certain mineralization time period₂And recording and storing.

Further, said CO-free₂The air production device also comprises CO₂Detecting the first component, CO₂The first detection bottle is filled with Ca (OH)₂A solution; said CO-free₂The air making bottle is communicated with CO through an air vent pipeline₂The detection bottle is connected with the CO₂The detection bottle is connected with the mineralization culture bottle through a ventilation pipeline.

Furthermore, the mineralization culture device also comprises a soil moisture monitor, a soil moisture sensor and an automatic moisture supplement device, wherein the soil moisture sensor monitors the water content of the soil sample, and the soil moisture monitor controls the automatic moisture supplement device to supplement water into the mineralization culture bottle according to the water content of the soil sample.

Further, the CO is₂The absorption calculating device also comprises CO₂Detecting the second bottle, CO₂The second detection bottle is filled with Ca (OH)₂Solution of said CO₂The two ends of the detection bottle pass through a vent pipeline and the CO₂The absorption bottles are connected.

Furthermore, each air pipeline is provided with a one-way valve; and in the mineralization culture flask and CO₂The air blocking clamp is arranged on the air vent pipeline between the absorption bottles.

Organic carbon mineralized CO in soil₂A method for continuously measuring a released amount, comprising the steps of:

1) in advance without CO₂Filling NaOH solution into an air making bottle, filling a soil sample into a mineralization culture bottle, and filling CO into the mineralization culture bottle₂Filling NaOH solution into the absorption bottle;

2) to no CO₂Introducing air into the air making bottle, wherein the CO is not contained₂Making CO-free in air making bottle₂Air, simultaneously opened from said CO-free₂The air making bottle is communicated with an air pipeline of the mineralization culture bottle;

3) continuously introducing CO-free into the mineralization culture bottle₂After a period of time in the air, the reaction is stopped to CO-free₂Introducing air into the air making bottle, and then opening the mineralized culture bottle to lead CO₂Vent line of absorption bottle simultaneously to said CO₂Phenolphthalein and BaCl are dripped into an absorption bottle₂A solution;

4) when the CO is present₂When the amount of white precipitate generated in the absorption bottle is not changed any more, the CO is added₂Dropwise adding HCl standard solution into an absorption bottle until the solution changes from pink to colorless;

5) calculating the soil organic carbon mineralization culture CO according to the following relational expression₂The release amount of (a):

CO absorption by NaOH₂The chemical reaction formula (II) is as follows:

2NaOH+CO₂＝Na₂CO₃+H₂O (1)

BaCl₂with Na₂CO₃The chemical reaction formula (II) is as follows:

Na₂CO₃+BaCl₂＝NaCl+BaCO₃↓ (2)

HCl titrates the chemical reaction of the remaining NaOH:

NaOH_(remainder)+HCl＝NaCl+H₂O (3)

Setting CO₂The initial concentration of NaOH solution in the absorption flask was C1, volume was V1, and the amount of initial material was n1 ═ C1 × V1;

setting the initial concentration of the HCl standard solution as C2 and the volume as V2, and the residual volume after titration as V3, wherein the amount of HCl substances consumed by titration is n2 ═ C2 ═ V2-V3;

then CO₂The amount of the residual NaOH substance in the absorption bottle is n 2;

then absorb CO₂Consumed ofThe amount of NaOH substance is n3 ═ n1-n 2;

the organic carbon in the soil mineralizes CO₂The released amount of (a) is M ═ (n1-n2) × M/2;

m is CO₂Molar mass of (a).

Further, the water content of the soil sample is maintained within a set range.

Further, the actually measured water content of the soil sample is obtained by adopting a multipoint measurement and averaging method; and when the actually measured water content is smaller than the required water content and the difference value between the actually measured water content and the required water content is larger than the threshold value, water is required to be supplemented.

Further, said CO-free₂Air making bottle connection CO₂Detecting bottle one, no CO₂Air passing through the CO₂The first detection bottle is introduced into the mineralization culture bottle, and the CO is₂The first detection bottle is filled with clarified Ca (OH)₂Solution of when said Ca (OH)₂And stopping the ventilation of the mineralization culture bottle when the solution is turbid.

Further, the CO is₂The absorption bottle is connected with CO₂A second detection bottle consisting of the said CO₂Introducing the gas discharged from the absorption bottle into the CO₂Detecting the second bottle; the CO is₂The second detection bottle is filled with clear Ca (OH)₂Solution of when said Ca (OH)₂Stopping the flow of the mineralized culture bottle to CO immediately when the solution is turbid₂Introducing gas into the absorption bottle to replace CO₂The aeration is continued after the absorption bottle.

Compared with the prior art, the invention has the following remarkable beneficial effects: 1) the invention designs twice CO of NaOH solution₂An absorption bottle for absorbing CO in air₂To ensure that the soil is free of CO when mineralized₂Doping and then reabsorbing CO released by soil mineralization₂To calculate the mineralized CO in the soil₂Content, and the accuracy of measurement is ensured. 2) Through continuous aeration and continuous reaction, the required soil oxygen is always kept in the mineralization culture bottle under long-time continuous culture, the soil is continuously mineralized, and the defect of inaccurate data caused by different mineralization conditions before and after culture in the original test is overcomeAnd (5) sinking. 3) Design Ca (OH)₂Two CO of solution₂Detecting the bottle once the CO in the air is found₂Immediately stopping aeration when introducing the water, and once discovering excessive CO due to soil mineralization₂If not measured, the NaOH vial was immediately replaced. 4) The moisture holding conditions are designed to allow the soil to mineralize under the required moisture conditions and under oxygen-rich conditions. 5) By using phenolphthalein and BaCl₂Titrating an indicator and HCl standard solution, reversely calculating the residual amount of NaOH solution, and then calculating the absorbed and mineralized CO₂The amount of NaOH consumed is used to calculate and mineralize CO₂The yield of the product is scientific and reasonable. 6) Only a certain amount of soil samples are weighed for culture, and CO released by mineralization of soil in different culture periods can be continuously collected and measured for a long time₂And the test times are reduced. 7) All reaction devices are closed in the whole process, and no external gas is doped.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the invention.

Drawings

FIG. 1 is a layout view of the measuring apparatus of the present invention.

In the figure, 1-air pump, 2-no CO₂Air making bottle, 3, 4, 6, 12, 16, 18-ventilating pipe, 5-CO₂A first detection bottle, a 7-one-way valve, an 8-soil moisture monitor, a 9-soil moisture sensor, a 10-moisture automatic supplement device, an 11-mineralization culture bottle, a 13-gas blocking clamp, a 14-automatic titration and calculation device, and a 15-CO₂Absorption bottle, 17-CO₂Detection bottle two, 19, 22-NaOH solution, 21-soil sample, 20, 23-Ca (OH)₂Solution, 24-porous plug.

Detailed Description

The present invention is described in detail below with reference to the drawings and examples, but it should be understood by those skilled in the art that the following examples are not intended to limit the technical solutions of the present invention, and any equivalent changes or modifications made within the spirit of the technical solutions of the present invention should be considered as falling within the protection scope of the present invention.

Referring to the layout of the measuring device given in FIG. 1, the organic carbon in the soil mineralizes CO₂The release amount measuring device is composed of a CO-free device₂Air production device, mineralization culture device, and CO₂The absorption calculating device is composed of three parts, wherein the three parts are connected by a ventilation pipeline, and CO₂Continuous measurement of the amount released was done under the device.

1. No CO₂Air making device

The part of the device is composed of an air pump 1 and CO-free NaOH solution 19 with sufficient quantity₂Air making bottle 2, containing clear Ca (OH)₂CO of solution 20₂A first detection bottle 5 and vent pipelines 3, 4 and 6.

In the absence of CO₂The air producing bottle 2 is previously filled with a sufficient amount of NaOH solution 19. One end of the vent pipeline 3 is connected with the air pump 1, and the other end is introduced into the CO-free pipeline₂In the air making bottle 2, ordinary air is injected into the CO-free air through the air pump 1 and the vent pipeline 3₂In the air making bottle 2, NaOH solution is utilized to absorb CO in the air₂Finally obtaining CO-free₂The gas is then conducted out through the ventilation line 4. No CO₂The air producing bottle 2 is a closed bottle body, the mouth of the bottle body is covered with a rubber porous plug 24, the holes of the porous plug 24 are not idle or closed except for useful holes, and the vent pipeline 3 and the vent pipeline 4 are inserted into the CO-free air bottle through the porous plug 24₂Air is made in the bottle 2.

Further, the vent line 3 is made CO-free₂The air inlet pipeline and the air vent pipeline 4 of the air making bottle 2 are used as CO-free pipelines₂The air makes the exhaust pipe of bottle 2, and the mouth of pipe of air pipe 3 is located below the NaOH liquid level, and the mouth of pipe of air pipe 4 is located above the NaOH liquid level.

In CO₂The first detection bottle 5 is filled with enough Ca (OH) in advance₂Solution 20 for detecting whether the NaOH solution 19 will CO₂The absorption is complete. Likewise, CO₂The first detection bottle 5 is also a closed bottle body, the bottle mouth is also covered with a porous plug 24, and the vent pipelines 4 and 6 are inserted into the CO through the porous plug 24₂And detecting in the first bottle 5.

No CO₂Air making bottle 2 and CO₂Detection bottleOne 5 is connected with the vent pipeline 4, and the vent pipeline 4 is CO-free₂The exhaust line of the air producing bottle 2, on the other hand as CO₂The air inlet pipeline of the detection bottle I5 has no CO₂Air making bottle 2 and CO₂The detection bottle I5 is connected without CO₂Air is led from the CO via the ventilation line 4₂The air producing bottle 2 is introduced into CO₂In the first detection bottle 5, in order to ensure that the prepared gas is completely free of CO₂Air.

Likewise, the vent line 4 serves as CO₂An air inlet pipeline and a ventilation pipeline 6 of the first detection bottle 5 are used as CO₂The exhaust pipeline of the first detection bottle 5 and the orifice of the vent pipeline 4 are positioned at Ca (OH)₂Below the liquid level, the mouth of the aeration line 6 is located at Ca (OH)₂Above the liquid surface. Further, a check valve 7 is provided on the vent line 6 for controlling the flow direction of the gas to prevent CO-free₂The air flows back. 2. Mineralizing culture device

The device comprises a soil moisture monitor 8, a soil moisture sensor 9, an automatic moisture supplement device 10, a mineralization culture bottle 11, a soil sample 21 and ventilation pipelines 6 and 12.

Similarly, the mineralization culture bottle 11 is also a closed bottle, the mouth of the bottle is covered by a porous plug 24, the ventilation pipes 6 and 12, the probe of the soil moisture sensor 9 and the water replenishing needle of the automatic water replenishing device 10 are inserted into the mineralization culture bottle 11 through the porous plug 24. A certain amount of soil samples 21 are pre-filled in the mineralization culture bottle 11, the soil moisture content is ensured to be within the range of the requirement of the test condition, and the invention aims to measure the mineralized CO of the soil samples 21₂And (4) releasing the amount.

Mineralizing culture apparatus and CO-free culture₂The air producing devices are connected by an air pipe 6, the air pipe 6 is used as CO₂The exhaust pipeline of the first detection bottle 5 is also used as an air inlet pipeline of the mineralization culture bottle 11 to introduce CO₂The first detection bottle 5 is communicated with the mineralization culture bottle 11 and has no CO₂Air from the CO through the vent line 6₂The first detection bottle 5 is continuously led into the mineralization culture bottle 11 to ensure that the mineralization process is always in an aerobic state and does not contain CO in the air₂。

Mineralization culture device and CO₂The absorption calculating means are connected by a ventilation line 12. The ventilation pipeline 12 is an exhaust pipeline of the mineralization culture bottle 11, and the ventilation pipeline 12 is provided with a one-way valve 7 and a gas blocking clamp 13 for controlling the flow direction of gas and preventing CO generated by soil mineralization₂Refluxing; the gas blocking clamp 13 is used for blocking CO in the mineralization culture bottle 11 after the soil mineralization culture reaches the required time₂Into CO₂An absorption calculation device.

The soil moisture sensor 9 is connected with the soil moisture monitor 8, and the soil moisture sensor 9 monitors the water content of the soil at multiple points in real time; the soil moisture monitor 8 calculates and processes the moisture content of the soil at multiple points acquired by the soil moisture sensor 9, the soil moisture monitor 8 automatically calculates and compares the difference between the average moisture content of the soil and the required moisture content (such as 80% of the saturated moisture content), and if the difference exceeds a set threshold (according to the requirement), the moisture is supplemented to the soil. The automatic water supplementing device 10 is also connected with the soil water monitor 8, and the soil water monitor 8 controls the automatic water supplementing device 10 to supplement water into the mineralization culture bottle 11 according to the calculation result, so that the condition of soil water is always kept unchanged in the mineralization process.

3.CO₂Absorption calculation device

The partial device comprises an automatic titration and calculation device 14 and CO₂Absorption bottle 15, CO₂A second detection bottle 17 and vent pipelines 12, 16 and 18.

CO₂The absorption bottle 15 is a closed bottle body, and the bottle mouth is covered with a porous plug 24, CO₂The absorption bottle 15 is filled with sufficient NaOH solution 22 to mineralize CO generated by soil₂Is introduced into the CO through a ventilation line 12₂In the absorption bottle 15, CO generated by mineralization is absorbed₂Absorbed by NaOH solution.

CO₂The second detection bottle 17 is also a closed bottle body, the bottle mouth is covered with a porous plug 24, CO₂The second detection bottle 17 contains enough clear Ca (OH)₂Solution 23, over CO₂The absorption bottle 15 absorbs CO₂The other gas enters into CO₂In the second detection bottle 17, CO generated by mineralization is detected₂Whether or not it is completely covered by CO₂The NaOH solution 22 in the absorption bottle 15 absorbs CO generated by mineralization₂Is completely covered with CO₂The NaOH solution in the absorption bottle 15 absorbs CO₂Detecting Ca (OH) in bottle II 17₂Solution is not observed, otherwise, CO₂Detection of clarified Ca (OH) in vial two 17₂The solution becomes turbid, at which point the gas-blocking clamp 13 should be closed and replaced by new CO₂And an absorption bottle 15.

The vent line 16 is CO₂The exhaust line of the absorption bottle 15 is CO₂Air inlet line, CO, of the second detection bottle 17₂The other absorbed gases enter the CO through the vent line 16₂And a second detection bottle 17, wherein the detected gas is discharged through a gas discharge pipeline 18. Further, to prevent the entry of outside air, a check valve 7 is also provided on the vent line 18.

Further, the vent line 12 acts as CO₂The absorbing bottle 15 is provided with an air inlet pipeline, the pipe orifice of the air inlet pipeline is positioned below the NaOH liquid level, the air vent pipeline 16 is used as an air vent pipeline, and the pipe orifice of the air vent pipeline is positioned above the NaOH liquid level; and vent line 16 as CO₂A second detection bottle 17 is provided with an air inlet pipeline, and the pipe orifice of the second detection bottle is positioned at Ca (OH)₂Below the level of the solution, the vent line 18 acts as a vent line, the orifice of which is located in Ca (OH)₂Above the surface of the solution. CO generated by soil mineralization in mineralization culture device₂Into the CO via a ventilation line 12₂After the absorption bottle 15 is filled with sufficient NaOH solution, the required mineralization culture time is reached, and CO is blocked by a gas blocking clamp₂Is continuously entered.

The auto-titration and calculation means 14 comprises: automatic agitator, indicator feeder, HCl titrator, color sensor, controller, automatic calculator and recorder. Automatic stirrer is inserted into CO₂The NaOH in the absorption bottle 15 is below the liquid level and is used for stirring the solution; the indicator is used for adding indicator to CO₂The phenolphthalein indicator and BaCl are dripped into the absorption bottle 15₂A solution; HCl titrator for feeding CO₂Dripping HCl standard solution into the absorption bottle 15, and titrating the residual NaOH in the bottle; the color sensor is used for sensing the color change of the solution in the reaction process, and when the HCl standard solution is titrated until the color of the solution is changed from pink to noneStopping dripping after coloring; the controller is used for comprehensively coordinating and controlling the actions of the automatic stirrer, the indicator feeder, the HCl titrator and the color sensor; the automatic calculating and recording device is used for calculating the soil CO in a certain mineralization time period by adopting a certain calculating method according to the dosage of the series of solutions₂And recording and storing.

The titration process was run essentially as follows: to show the end of the reaction, phenolphthalein indicator was first added to the absorption flask via an indicator feeder for a set time, followed by the dropwise addition of BaCl₂The automatic stirrer starts the stirring function of the solution to ensure the accuracy of the titration result, the characteristic that phenolphthalein changes the color of the solution is utilized to indicate the result that HCl titrates NaOH, and BaCl is utilized₂With Na₂CO₃The formation of white precipitate by the reaction proves that CO is present₂Is absorbed; simultaneously, respectively starting a titration function and a color sensing function by an HCl titrator and a color sensor, and dropwise adding HCl standard solution with certain concentration and volume by the HCl titrator to titrate the residual NaOH in the bottle; and (3) sensing the color change of the solution in the reaction process by using a color sensor, and stopping the operation of the automatic stirrer, the HCl titrator and the color sensor after the HCl standard solution is titrated until the color of the solution is changed from pink to colorless, so that the titration process is finished.

Automatically titrating NaOH in an absorption bottle to an end point by using HCl standard solution with standard concentration, and calculating CO generated by soil mineralization in the culture time according to the consumption of HCl₂And (4) releasing the amount. If the measurement is needed, the CO is replaced by new CO₂After the absorption bottle, the gas blocking clamp is opened again and new CO is used₂NaOH in the absorption bottle is continuously absorbed to the specified culture time, and titration and calculation are carried out. This is repeated, so that the effect of continuous measurement can be achieved.

The invention provides a method for mineralizing CO by using soil organic carbon₂The specific method for continuously measuring the release amount comprises the following steps:

(1) CO-free in the above-mentioned plant₂The air making bottle 2 is filled with sufficient NaOH solution; in CO₂The absorption bottle 15 is also filled with sufficient NaOH solution; the mineralized culture bottle 11 is filled with water with the required water content of W₁A certain amount of a soil samplePreparing a product; adding phenolphthalein and BaCl into an indicator feeder₂A solution; the HCl titrator was charged with a standard solution of HCl at a concentration of C2 and a volume of V2.

(2) Setting the measured water content and the required water content W₁A threshold value a of the difference value, when the measured moisture content is less than the required moisture content W₁And when the difference is larger than the threshold a, water is required to be supplemented. E.g., setting the required water content W₁Is saturated water content W₀And when the difference value between the actually measured water content and the required water content is smaller than a threshold value a, water is required to be supplemented, and the expression is as follows:

in the above formula, the water content, W, is measured by a multipoint measuring method_iThe water content of the ith point is, N is the number of measuring points, and the actually measured water content is the average value of the water content of multiple points.

(3) Preparing the device according to the connection relationship, starting the test, and using air pump 1 to remove CO₂Pumping air into the air making bottle 2, and utilizing CO-free₂Sufficient NaOH solution in the air making bottle 2 absorbs CO pumped into the air₂At this time, no CO is present₂The exhaust gas ventilation pipeline 4 of the air making device is opened to absorb CO₂After air introduction of CO₂In the first detection bottle 5, the existence of excessive CO is detected₂Not absorbed and then reintroduced into the mineralization culture flask 11.

(4) Continuously introducing CO-free gas into the mineralization culture bottle 11₂After the air is in a certain time, the air pump is closed to prevent excessive CO₂Introducing and then opening an exhaust ventilation pipeline 12 of the mineralization culture device to mix the mixture generated by CO through soil mineralization₂Is introduced into CO₂In the absorption bottle 15.

(5) By using CO₂The NaOH solution in the absorption bottle 15 absorbs and mineralizes CO generated₂In combination with BaCl₂Detection of white precipitate BaCO₃To prove CO₂Is absorbed.

(6) In CO₂Absorption and mineralization of NaOH solution in the absorption bottle 15Raw CO₂After a period of time, if the production of white precipitate is found to be unchanged, the CO is shifted to CO₂Dripping HCl standard solution into the absorption bottle 15 to titrate the residual NaOH solution, simultaneously using phenolphthalein indicator to indicate the residual NaOH solution, stopping dripping when the color is changed from pink to colorless, and carrying out soil organic carbon mineralization to culture CO₂The amount of release of (c) is calculated.

The corresponding chemical reaction formula and calculation method are as follows:

CO absorption by NaOH₂The chemical reaction formula (II) is as follows:

2NaOH+CO₂＝Na₂CO₃+H₂O (1)

BaCl₂with Na₂CO₃The chemical reaction formula (II) is as follows:

Na₂CO₃+BaCl₂＝NaCl+BaCO₃↓ (2)

the HCl standard solution titrates the remaining NaOH solution and phenolphthalein indicator indicates the chemical reaction formula for the color change:

NaOH_(remainder)+HCl＝NaCl+H₂O (3)

Setting CO₂The amount of NaOH solution initially in the absorption flask 15 was sufficient to have an initial concentration of C1 and a volume of V1, so that the amount of the initial NaOH solution mass was n1 — C1 × V1;

the initial concentration of HCl standard solution is C2, and the volume is V₂And the volume remaining after titration is V3, the amount of substance titrating to consume HCl is n2 ═ C2 ═ V2-V3;

then CO₂Sufficient NaOH solution in the absorption bottle 15 absorbs CO₂The amount of NaOH remaining after that was n 2;

then absorb CO₂The amount of NaOH consumed was n3 ═ n1-n 2;

the organic carbon in the soil mineralizes CO₂The release amount is M ═ (n1-n2) × M/2.

The above concentration units (g/mol), volume units (ml), CO₂The molar mass M of (2) is 44 g/mol.

The release amount is from the opening of a mineralized culture bottle 11 to CO₂The vent line of the absorption bottle 15 is started and is dropped with HCl standard liquidAnd (3) until the solution changes from pink to colorless, and the organic carbon in the soil mineralizes CO in the period of time₂And (4) releasing the amount.

Further, utilizing CO₂Detecting CO with the second detection bottle 17₂The amount of NaOH solution in the absorption bottle 15 is sufficient or insufficient, and if the amount of NaOH solution is sufficient, CO is present₂Detection of clarified Ca (OH) in vial two 17₂The solution has no turbidity, otherwise, CO₂Detection of clarified Ca (OH) in vial two 17₂The solution becomes turbid, at which point the gas-blocking clamp 13 should be closed and replaced by new CO₂And an absorption bottle 15.

Further, in the soil organic carbon mineralization process, through soil moisture sensor 9 real-time supervision soil moisture, when finding that the measured water content is less than the required water content and the difference between them is greater than threshold a, then through the moisturizing automatic supplement unit 10 to moisturizing in the soil.

And simultaneously, the color change of the solution in the reaction process is sensed by a color sensor during the titration of the phenolphthalein indicator, and the dropwise addition is stopped when the HCl standard solution is titrated until the color of the solution is changed from pink to colorless.

Further, after the indicator is added, the automatic stirrer starts the stirring function to ensure the accuracy of the titration result.