Absorption liquid, nitrous acid detection device and nitrous acid detection method

Abstract

The invention relates to a spectrum technology, and particularly provides an absorption liquid and a nitrous acid detection device and method.The nitrous acid detection device comprises an absorption unit, a detection unit and an analysis unit; according to the absorption unit, gas to be detected enters a first pipeline under pumping of a pump; the second pipeline is communicated with the first pipeline, and the absorption liquid enters the first pipeline through the second pipeline; the first gas-liquid separation unit is communicated with the first pipeline, separated liquid enters a third pipeline, and the third pipeline is connected with the detection unit. The method has the advantages of high absorption efficiency, short stabilization time, accurate detection and the like, and is applied to detection of nitrous acid in gas.

Description

Technical Field

[0001] The invention relates to spectral technology, and in particular to an absorption liquid, a nitrous acid detection device and a method. Background Art

[0002] Gaseous nitrous acid (HONO) is one of the important sources of OH radicals in the atmosphere and plays an important role in the atmospheric environment. It affects the oxidation reaction process and the formation of secondary pollutants in the atmosphere. In a strong oxidizing environment, it will accelerate the production of ozone (O3) pollution and PM2.5, and plays a key role in the atmospheric photochemical process.

[0003] In order to absorb and detect gaseous nitrous acid, the prior art adopts a phased solution, specifically:

[0004] 1. The first step: The ambient air is first mixed with the mixture of sulfonamide and phosphoric acid, and the nitrous acid in the air is absorbed by the mixture to form diazonium salt.

[0005] 2. The second step: react with the concentrated naphthalene ethylenediamine hydrochloride introduced, and the diazonium salt combines with the concentrated naphthalene ethylenediamine hydrochloride to form a rose-colored azo dye.

[0006] 3. Step 3: Utilize the absorption characteristics of azo dyes to achieve accurate quantification of HONO concentration.

[0007] The shortcomings of the above solution are: 1. The absorption efficiency of nitrite is relatively low, only about 90%.

[0008] 2. The sample takes a long time to stabilize, which takes 50 minutes, severely limiting the implementation of rapid testing. Summary of the invention

[0009] In order to solve the deficiencies in the above-mentioned prior art solutions, the present invention provides an absorption liquid for nitrous acid detection.

[0010] The object of the present invention is achieved through the following technical solutions: An absorption liquid comprises sulfonamide, concentrated naphthylethylenediamine hydrochloride, concentrated hydrochloric acid and a solvent.

[0011] The object of the present invention is also to provide a nitrous acid detection device using the above-mentioned absorption liquid, and the object of the invention is achieved through the following technical solutions: A nitrous acid detection device comprises an absorption unit, a detection unit and an analysis unit; the absorption unit comprises: A first pipeline and a pump, under the suction of the pump, the gas to be tested enters the first pipeline; a second pipeline, the second pipeline is connected to the first pipeline, and the absorption liquid of the present invention enters the first pipeline through the second pipeline; A first gas-liquid separation unit and a third pipeline, wherein the first gas-liquid separation unit is connected to the first pipeline, and the separated liquid enters the third pipeline, and the third pipeline is connected to the detection unit.

[0012] The present invention also aims to provide a method for detecting nitrous acid, which is achieved by the following technical solutions: The nitrite detection method is as follows: Under the pumping, the gas to be tested enters the first pipeline, and at the same time, the reaction liquid of the present invention enters the first pipeline through the second pipeline, and the gas to be tested and the reaction liquid are mixed, absorbed and reacted; The mixed liquid undergoes the first gas-liquid separation, and the separated liquid is sent to the detection unit through the third pipeline.

[0013] Compared with the prior art, the present invention has the following beneficial effects: 1. High absorption efficiency; The absorption liquid is prepared at one time, and there is no need to add each component in stages, which improves the absorption efficiency of nitrous acid. Experiments show that the absorption efficiency exceeds 99%; 2. Short stabilization time; The sample (reaction solution after absorbing nitrous acid) has a short stabilization time, which shortens the detection time accordingly; 3. Accurate detection; The absorption liquid is used to achieve high-efficiency absorption of nitrite, which correspondingly improves the detection accuracy; The difference between the first signal and the second signal corresponds to background subtraction, which further improves the detection accuracy of nitrous acid. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The disclosure of the present invention will become easier to understand with reference to the accompanying drawings. It is easy for those skilled in the art to understand that these drawings are only used to illustrate the technical solution of the present invention and are not intended to limit the scope of protection of the present invention. In the drawings: Figure 1 is a simplified structural diagram of an absorption unit according to an embodiment of the present invention; Figure 2-Figure 3 It is a comparative diagram of stabilization time. DETAILED DESCRIPTION

[0015] Figure 1-Figure 3The following description describes optional specific embodiments of the present invention to teach those skilled in the art how to implement and reproduce the present invention. In order to teach the technical solution of the present invention, some conventional aspects have been simplified or omitted. Those skilled in the art will understand that variations or replacements derived from these specific embodiments will be within the scope of the present invention. Those skilled in the art will understand that the following features can be combined in various ways to form multiple variations of the present invention. Thus, the present invention is not limited to the following optional specific embodiments, but is only limited by the claims and their equivalents.

[0016] Example 1.

[0017] The absorption liquid of the embodiment of the present invention comprises sulfonamide, concentrated naphthylethylenediamine hydrochloride, concentrated hydrochloric acid and a solvent, wherein the solvent is ultrapure water.

[0018] The nitrous acid detection device of the embodiment of the present invention comprises an absorption unit, a detection unit and an analysis unit; Figure 1 As shown, the absorption unit is: Under the suction of the pump, the gas to be tested enters the first pipeline 11 .

[0019] The second pipeline 12 is connected to the first pipeline 11 , and the absorption liquid in this embodiment enters the first pipeline 11 through the second pipeline 12 .

[0020] The first gas-liquid separation unit 21 is connected to the first pipeline 11 downstream of the second pipeline 12, and the separated liquid enters the third pipeline 13, and the third pipeline 13 is connected to the detection unit.

[0021] In order to improve the detection accuracy, further, the absorption unit includes: The fourth pipeline 14 is connected to the first pipeline 11 downstream of the first gas-liquid separation unit 21 , and the absorption liquid in this embodiment enters the first pipeline 11 through the fourth pipeline 14 .

[0022] The second gas-liquid separation unit 22 is connected to the first pipeline 11 downstream of the fourth pipeline 14, and the separated liquid enters the fifth pipeline 15, and the fifth pipeline 15 is connected to the detection unit; A switching module is used to enable the detection unit to selectively connect to the third pipeline 13 or the fifth pipeline 15 .

[0023] In order to improve the detection accuracy, further, the analysis unit includes: A calculation module, wherein the calculation module is used to obtain the difference between a first signal and a second signal (after deducting the background), wherein the first signal is the output signal of the detection unit when the liquid in the third pipe 13 is sent to the detection unit, and the second signal is the output signal of the detection unit when the liquid in the fifth pipe 15 is sent to the detection unit.

[0024] The analysis unit analyzes the difference to obtain the concentration of nitrous acid in the gas to be tested.

[0025] In order to improve the detection accuracy and shorten the detection time, the detection unit further comprises: A light source, a circulation cell and a detector, wherein the light source emits measurement light and passes through the circulation cell, and the detector is used to measure the transmitted light of the light passing through the liquid in the circulation cell and output the first signal and the second signal; the circulation cell is connected to the switching module.

[0026] The nitrous acid detection method of the embodiment of the present invention is specifically as follows: Under the pumping, the gas to be measured enters the first pipe 11, and at the same time, the reaction liquid of this embodiment enters the first pipe 11 through the second pipe 12, and the gas to be measured and the reaction liquid are mixed, absorbed and reacted.

[0027] The mixed liquid undergoes a first gas-liquid separation, and the separated liquid is sent to the detection unit through the third pipeline 13.

[0028] In order to improve the detection accuracy, further, in the first gas-liquid separation, the separated gas continues to be transmitted in the first pipeline 11, mixed, absorbed and reacted with the reaction liquid entering the first pipeline 11 through the fourth pipeline 14, and then the second gas-liquid separation is performed, and the separated liquid is sent to the detection unit through the fifth pipeline 15; The third pipe 13 and the fifth pipe 15 selectively communicate with the detection unit.

[0029] When the liquid in the third pipe 13 is sent to the detection unit, the detection unit outputs a first signal, and when the liquid in the fifth pipe 15 is sent to the detection unit, the detection unit outputs a second signal.

[0030] The calculation module obtains a difference between the first signal and the second signal.

[0031] The analysis unit analyzes the difference to obtain the concentration of nitrous acid in the gas to be tested.

[0032] In order to improve the detection accuracy and shorten the detection time, further, the working mode of the detection unit is: The light source emits measuring light and passes through the liquid in the circulation pool. The detector is used to receive the transmitted light of the measuring light passing through the circulation pool and output an electrical signal. The third pipe 13 and the fifth pipe 15 selectively connect to the circulation pool.

[0033] Example 2.

[0034] An example of application of the nitrous acid detection device and method in Example 1 of the present invention in air monitoring.

[0035] In this application example, Figure 1As shown, the first pipeline 11 is spiral, and the tail end is connected to an air pump for pumping air into the first pipeline 11. The second pipeline 12, the first gas-liquid separation unit 21, the fourth pipeline 14 and the second gas-liquid separation unit 22 are arranged on the first pipeline 11 in sequence.

[0036] The third pipeline 13 is connected to the liquid outlet of the first gas-liquid separation unit 21, the fifth pipeline 15 is connected to the liquid outlet of the second gas-liquid separation unit 22, and the switching module adopts a three-way valve to achieve selective connection between the third pipeline 13 and the fifth pipeline 15 and the detection unit.

[0037] In the detection unit, the light source and the detector are arranged on both sides of the flow cell, the wavelength of the measuring light emitted by the light source includes 550nm, and the outlet of the three-way valve is connected to the flow cell.

[0038] In the analysis unit, the calculation module outputs the difference between the first signal and the second signal. When the liquid in the third pipe 13 is sent to the circulation pool, the detector outputs the first signal, and when the liquid in the fifth pipe 15 is sent to the circulation pool, the detector outputs the second signal. The analysis module processes the difference according to the absorption spectrum technology to obtain the concentration of nitrous acid in the air.

[0039] The nitrous acid detection method of the embodiment of the present invention is specifically as follows: Under the pumping, air enters the first pipe 11, and at the same time, the reaction liquid enters the first pipe 11 through the second pipe 12, and the nitrous acid in the air mixes, absorbs and reacts with the reaction liquid.

[0040] Reaction solution: 20 g sulfonamide, 50 ml concentrated hydrochloric acid, 2000 ml ultrapure water and 0.2 g concentrated naphthylethylenediamine hydrochloride are prepared at once.

[0041] The mixed liquid undergoes the first gas-liquid separation, and the separated liquid is sent to the detection unit through the third pipe 13. The separated gas continues to flow forward in the first pipe 11, and is mixed, absorbed and reacted again with the reaction liquid entering the first pipe 11 through the fourth pipe 14. After the second gas-liquid separation, the separated liquid is sent to the detection unit through the fifth pipe 15.

[0042] By switching the three-way valve, when the liquid in the third pipe 13 is sent to the circulation pool, the detector outputs a first signal, and when the liquid in the fifth pipe 15 is sent to the circulation pool, the detector outputs a second signal, and the second signal serves as background.

[0043] The calculation module obtains the difference between the first signal and the second signal, thereby subtracting the background.

[0044] The analysis unit analyzes the difference using absorption spectrum technology to obtain the concentration of nitrous acid in the gas to be tested.

[0045] The results show that the absorption efficiency of nitrous acid reaches 99.39% when using the absorption liquid of this example.

[0046] Example 3.

[0047] According to the application example of the nitrous acid detection device and method in Example 1 of the present invention in air monitoring, the difference from Example 2 is that: The switching module uses a peristaltic pump, which is respectively arranged on the third pipeline 13 and the fifth pipeline 15, for conveying liquid and controlling whether the pipeline is connected to the circulation pool.

[0048] Verification Example 1: 1. Pass 10ppb standard gas, first add 20g sulfonamide + 200mL phosphoric acid + 1L ultrapure water, then add 0.2g concentrated naphthylethylenediamine hydrochloride + 2L ultrapure water; Multiple components were added at different times, and a stable value of about 10 ppb was reached at the 10th point after the introduction of 10 ppb standard gas, such as Figure 2 As shown, it takes 5 minutes to stabilize a point and 50 minutes.

[0049] 2. The absorption liquid is: 20g sulfonamide + 0.2g concentrated naphthalene ethylenediamine hydrochloride + 200mL concentrated hydrochloric acid + 2L ultrapure water, which is prepared in one step. After the 10ppb standard gas is introduced, the 6th point reaches a stable value of 10ppb. Figure 3 As shown, it takes 30 min to reach stability.

[0050] It can be seen that compared with the prior art of adding each component in stages, the stabilization time required by the present invention is significantly shortened, which is conducive to rapid and accurate detection.

[0051] Verification Example 2: Using this detection device, before and after the first gas-liquid separation, 20g sulfonamide + 200mL phosphoric acid + 2L ultrapure water, and + 0.2g concentrated naphthylethylenediamine hydrochloride were added in stages, and the tested nitrous acid absorption efficiency was 90.05%.

[0052] Before and after the first gas-liquid separation, 20 g of sulfonamide, 200 ml of concentrated hydrochloric acid, 2000 ml of ultrapure water and 0.2 g of concentrated naphthylethylenediamine hydrochloride were added at a time, and the tested nitrous acid absorption efficiency was 99.78%.

[0053] It can be seen that compared with the prior art, the present invention has higher absorption efficiency.

Claims

1. An absorption liquid; characterized in that, The absorption liquid comprises sulfonamide, concentrated naphthylethylenediamine hydrochloride, concentrated hydrochloric acid and a solvent.

2. The absorption liquid according to claim 1, characterized in that The solvent is ultrapure water.

3. A nitrous acid detection device, comprising an absorption unit, a detection unit and an analysis unit; characterized in that: The absorption unit comprises: A first pipeline and a pump, under the suction of the pump, the gas to be tested enters the first pipeline; a second pipeline, the second pipeline is connected to the first pipeline, and the absorption liquid according to claim 1 or 2 enters the first pipeline through the second pipeline; A first gas-liquid separation unit and a third pipeline, wherein the first gas-liquid separation unit is connected to the first pipeline, and the separated liquid enters the third pipeline, and the third pipeline is connected to the detection unit.

4. The nitrous acid detection device according to claim 3, characterized in that: The absorption unit comprises: a fourth pipeline, the fourth pipeline being connected to the first pipeline downstream of the first gas-liquid separation unit, and the absorption liquid according to claim 1 or 2 enters the first pipeline through the fourth pipeline; a second gas-liquid separation unit and a fifth pipeline, wherein the second gas-liquid separation unit is connected to the first pipeline downstream of the fourth pipeline, and the separated liquid enters the fifth pipeline, and the fifth pipeline is connected to the detection unit; A switching module is used to enable the detection unit to selectively connect to the third pipeline or the fifth pipeline.

5. The nitrous acid detection device according to claim 4, characterized in that, The analysis unit comprises: A calculation module, the calculation module is used to obtain a difference between a first signal and a second signal, the first signal is an output signal of the detection unit when the liquid in the third pipeline is sent to the detection unit, and the second signal is an output signal of the detection unit when the liquid in the fifth pipeline is sent to the detection unit; The analysis unit analyzes the difference to obtain the concentration of nitrous acid in the gas to be tested.

6. The nitrous acid detection device according to claim 5, characterized in that: The detection unit comprises: A light source, a circulation cell and a detector, wherein the light source emits measurement light and passes through the circulation cell, and the detector is used to measure the transmitted light of the light passing through the liquid in the circulation cell and output the first signal and the second signal; the circulation cell is connected to the switching module.

7. Nitrite detection method, specifically: Under the pumping, the gas to be tested enters the first pipeline, and at the same time, the reaction liquid described in claim 1 or 2 enters the first pipeline through the second pipeline, and the gas to be tested and the reaction liquid are mixed, absorbed and reacted; The mixed liquid undergoes the first gas-liquid separation, and the separated liquid is sent to the detection unit through the third pipeline.

8. The nitrous acid detection method according to claim 7, wherein In the first gas-liquid separation, the separated gas continues to be transmitted in the first pipeline, mixed, absorbed and reacted with the reaction liquid entering the first pipeline through the fourth pipeline, and then the second gas-liquid separation is performed, and the separated liquid is sent to the detection unit through the fifth pipeline; The third pipe and the fifth pipe are selectively connected to the detection unit.

9. The method for detecting nitrous acid according to claim 8, wherein: When the liquid in the third pipe is sent to the detection unit, the detection unit outputs a first signal, and when the liquid in the fifth pipe is sent to the detection unit, the detection unit outputs a second signal; The calculation module obtains the difference between the first signal and the second signal; The analysis unit analyzes the difference to obtain the concentration of nitrous acid in the gas to be tested.

10. The method for detecting nitrous acid according to claim 9, wherein: The working mode of the detection unit is: The light source emits measuring light and passes through the liquid in the circulation pool. The detector is used to receive the transmitted light of the measuring light passing through the circulation pool and output an electrical signal. The third pipe and the fifth pipe selectively connect to the circulation pool.

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