CN107064029A - A kind of nitrous acid and concentration of nitric acid on-line measurement system and measuring method - Google Patents
A kind of nitrous acid and concentration of nitric acid on-line measurement system and measuring method Download PDFInfo
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- CN107064029A CN107064029A CN201710079043.7A CN201710079043A CN107064029A CN 107064029 A CN107064029 A CN 107064029A CN 201710079043 A CN201710079043 A CN 201710079043A CN 107064029 A CN107064029 A CN 107064029A
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- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
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Abstract
The invention discloses a kind of nitrous acid and concentration of nitric acid real-time online measuring system and method, the system includes external sample injection unit, liquid phase chemical conversion unit and the optical absorption detection unit being sequentially connected；External sample injection unit is used for nitrogen-containing compound sample introduction；It is nitrite that liquid phase chemical conversion unit, which is used for the nitrogen-containing compound sorption enhanced from external sample injection unit,；It is the absorbent material with UV, visible light that optical absorption detection unit, which is used for the Nitrite transformation from liquid phase chemical conversion unit, and carries out optical detection；The system is measured while can realizing to nitrous acid and nitric acid, while the interference of other gaseous substances can also be eliminated by parallel channels.The system can realize the trace detection to nitrous acid in air and nitric acid, and the trace of nitrous acid in water body and nitric acid is monitored, and detection sensitivity is better than 10pptv and 0.03 μ g/L, and the response time is less than 3 5min；It can be used in terms of atmospheric environment, water body environment monitoring, experimental science research.
Description
Technical field
The present invention relates to atmospheric environment detection and experimental science research field, specially a kind of nitrous acid and concentration of nitric acid are real
When on-line measurement system and measuring method.
Background technology
Nitrous acid (HONO) is a kind of nitrogen substance of trace in air, is also a kind of more typical secondary pollution,
Its concentration can be used as the index for directly reflecting urban atmospheric pollution degree.Nitric acid (HNO3) it is nitrogen oxides in an atmosphere important
Oxidation product, it can be generated by radical reaction, be produced while can also be hydrolyzed by dinitrogen pentoxide, in influence atmospheric nitrogen
Global environment is influenceed by dried wet deposition while circulation.As city gray haze event takes place frequently, to gaseous state nitrous acid and nitric acid
Research is also increasingly becoming a hot issue, but is due to that concentration is low in an atmosphere, the reason such as reactivity is big, to both height
Precision measure is extremely difficult.
The detection method for nitrous acid (HONO) more maturation mainly has diffusion Manifold technology, chemoluminescence method, base at present
In dinitrophenylhydrazine (DNPH) derivative-high performance liquid chromatography (HPLC) method, mass spectrum (Mass spectrometry) method, spectrum side
Method (including UV-PF/LIF, Fourier infrared spectrum (FTIR)) etc.；For nitric acid (HNO3) then mainly will using wet absorption method
Gaseous state nitric acid is converted into nitrate ion, and then using UV spectroscopic methodologies/photometry, the chromatography of ions (Ion
Chromatography, IC) etc. carry out the measure of nitrate ion so that the concentration of correspondence gaseous state nitric acid.But above method is big
It is faced with some limitations more, is on the one hand that interference gas is more, causes the HONO concentration values of measurement may be inaccurate；On the other hand
Limit for height is exactly detected, the HONO measurements for low concentration on daytime do not reach requirement.
Therefore a kind of high selectivity high-precision measuring method is developed for HONO and HNO in detection air in real time3Concentration,
Atmospheric oxidn potentiality is estimated, or even understands and solve China's atmosphere polluting problem in depth there is potential function and significance.
The content of the invention
In order to overcome the shortcomings and deficiencies of existing detection technique, the present invention is inhaled based on wet absorption, chemical conversion and optics
The method of receipts, develops a kind of nitrous acid and concentration of nitric acid real-time online measuring system and measuring method.The system can be realized
To gaseous state nitrous acid (HONO) and nitric acid (HNO in air3) while measure, with good linearity, test limit is low, favorable reproducibility etc.
Feature, while the interference of other gaseous substances can be eliminated by parallel channels, it is with a high credibility.In addition, different by replacing
Sampling system, also can carry out on-line synchronous measurement, with above-mentioned gaseous material to the nitrite in liquid phase and nitrate concentration
The same effect of detection.The system both can be used for atmosphere environment supervision, it can also be used in terms of experimental science research.It is described to survey
Amount method is to use described device.
The present invention seeks to what is be achieved through the following technical solutions：
A kind of nitrous acid and concentration of nitric acid real-time online measuring system, the system includes the external sample introduction list being sequentially connected
Member, liquid phase chemical conversion unit and optical absorption detection unit；External sample injection unit is used for nitrogen-containing compound sample introduction；Liquid phase chemical
It is nitrite that conversion unit, which is used for the nitrogen-containing compound sorption enhanced from external sample injection unit,；Optical absorption detection unit
For being the absorbent material with ultraviolet-visible by the Nitrite transformation from liquid phase chemical conversion unit, and carry out light
Learn detection；
The liquid phase chemical conversion unit includes the first liquid phase chemical conversion unit and second liquid phase chemical conversion unit；
The optical absorption detection unit includes the first optical absorption detection unit and the second optical absorption detection unit；
In the external sample injection unit, nitrous acid to be detected and nitric acid and the entrance point of the external sample injection unit connect
Logical, external sample injection unit includes two ports of export, is designated as first outlet end and second outlet end, turns respectively with the first liquid phase chemical
Change unit and the connection of second liquid phase chemical conversion unit；
The rear end of first liquid phase chemical conversion unit is connected with the first optical absorption detection unit, second liquid phase chemical conversion
The rear end of unit is connected with the second optical absorption detection unit；Second optical absorption detection unit can only obtain impurity and be converted into
Nitrite and nitrate concentration, and be used as background deduction；First optical absorption detection unit can be in acquisition system
And the concentration of the nitrite that is converted into of impurity and nitrate, pass through the background button for deducting the second optical absorption detection unit
Except item, that is, obtain the concentration of system nitrite and nitrate.
According to the present invention, described external sample injection unit includes gas phase sample injection unit and liquid-phase inlet unit.
According to the present invention, described gas phase sample injection unit includes gas absorbing device, and the gas absorbing device includes the
One aerosol filtration device, the first absorption tube, the second absorption tube, the first fluid reservoir A and two two-port valves；First aerosol
Filter is connected with the first absorption tube, and first absorption tube is connected with the second absorption tube；The first of the first fluid reservoir A
Liquid outlet is connected with the first absorption tube；The second liquid outlet of the first fluid reservoir A is connected with the second absorption tube；Described first inhales
Closed tube is connected by the first two-port valve with first outlet end, and second absorption tube is connected by the second two-port valve and second outlet end
Connect.
According to the present invention, described gas phase sample injection unit also includes air extractor, and the air extractor includes aspiration pump, gas
Body flow controller, the second aerosol filtration device and safety flack；The aspiration pump is connected with gas flow controller, the gas
Body flow controller is connected with the second aerosol filtration device, and the second aerosol filtration device is connected with safety flack；It is described
Safety flack is connected with the second absorption tube in gas absorbing device.
According to the present invention, described liquid-phase inlet unit includes the second fluid reservoir S and permeable membrane device, second liquid storage
Tank S sets two liquid outlets, is designated as the 3rd liquid outlet and the 4th liquid outlet；3rd liquid outlet passes through the 3rd two-port valve and
One port of export is connected, and the 4th liquid outlet is connected with the entrance of the permeable membrane device, and the outlet of the permeable membrane device leads to
The 4th two-port valve is crossed to be connected with second outlet end.
According to the present invention, the first liquid phase chemical conversion unit includes the first absorption circuit and the first conversion circuit；
First absorption circuit includes the first mixing chamber, outlet and the optical absorption detection unit of first mixing chamber
It is connected；
The first conversion circuit includes the first conversion tube, the second mixing chamber and the first buffer pool, first conversion tube
Outlet be connected with the entrance of second mixing chamber；The outlet of second mixing chamber and the entrance phase of first buffer pool
Even；The outlet of first buffer pool is connected with optical absorption detection unit；
The first liquid phase chemical conversion unit is connected with first outlet end, and the first outlet end is divided into two-way, all the way
It is connected with the entrance of the first mixing chamber in the first absorption circuit, another road is connected with the first conversion tube of the first conversion circuit.
According to the present invention, the second liquid phase chemical conversion unit includes the second absorption circuit and the second conversion circuit；
Second absorption circuit includes the 3rd mixing chamber, outlet and the optical absorption detection unit of the 3rd mixing chamber
It is connected；
The second conversion circuit includes the second conversion tube, the 4th mixing chamber and the second buffer pool, second conversion tube
Outlet be connected with the entrance of the 4th mixing chamber；The outlet of 4th mixing chamber and the entrance phase of second buffer pool
Even；The outlet of second buffer pool is connected with optical absorption detection unit；
The second liquid phase chemical conversion unit is connected with second outlet end, and the second outlet end is divided into two-way, all the way
It is connected with the entrance of the 3rd mixing chamber in the second absorption circuit, another road is connected with the second conversion tube of the second conversion circuit.
According to the present invention, the liquid phase chemical conversion unit still further comprises the 3rd fluid reservoir B；3rd fluid reservoir
B liquid introduces the first liquid phase chemical conversion unit and second liquid phase chemistry before the first and second port of export branches respectively
In conversion unit；Or, after the first and second port of export branches, it is introduced between the first mixing in the first absorption circuit
Before room, first conversion circuit the first conversion tube before, before the 3rd mixing chamber in the second absorption circuit, the second transition lines
Before second conversion tube on road；The either combination of above two incorporation way.
According to the present invention, the liquid phase chemical conversion unit still further comprises the 4th fluid reservoir R, the 4th fluid reservoir
R liquid be introduced between the first mixing chamber in the first absorption circuit before, the first conversion tube of the first conversion circuit and the
Before the 3rd mixing chamber between two mixing chambers, in the second absorption circuit, the second conversion tube of the second conversion circuit and the 4th mixed
Between conjunction room.
According to the present invention, the optical absorption detection unit includes four optical absorption detection units, light source and detector；
The first optical absorption detection unit includes the first absorption cell, the outlet of the first mixing chamber and the entrance phase of the first absorption cell
Even；The second optical absorption detection unit includes the second absorption cell, outlet and the second absorption cell of first buffer pool
Entrance is connected；The 3rd optical absorption detection unit includes the 3rd absorption cell, outlet and the 3rd absorption cell of the 3rd mixing chamber
Entrance be connected；The 4th optical absorption detection unit includes the 4th absorption cell, the outlet and the 4th of second buffer pool
The entrance of absorption cell is connected；Entrance of the light source respectively with four absorption cells is connected, and the detector absorbs with four respectively
The outlet in pond is connected.
According to the present invention, the system also includes one or more parallel channels for further eliminating interfering material influence, institute
Stating each parallel channels includes absorption tube, conversion tube, two absorption cells, infusion pump, light source and detector, parallel logical
The connected mode and liquid phase chemical conversion unit and optics of absorption tube, conversion tube, absorption cell, infusion pump and detector in road
The connection of corresponding component and the method for operation are identical in absorption detecting unit.If multiple parallel channels, the multiple parallel channels
In absorption tube be connected with the absorption tube of previous parallel channels.
According to the present invention, the on-line monitoring system also includes computer control unit, for controlling the intensity of light source, flow control
The detection data of the uninterrupted of device processed, the output flow of infusion pump and acquisition testing device.
According to the present invention, the first aerosol filtration device and the second aerosol filtration device are gone using filter membrane or collision
Except system；The filter membrane material can elect the one or more in quartz, glass fibre or polytetrafluoroethylene (PTFE), the aperture of filter membrane as
Scope is 0.002-100 μm.
According to the present invention, the fluid reservoir can be using resistant materials, described first such as glass, plastics, polytetrafluoroethylene (PTFE)
Absorbing liquid in fluid reservoir can be using alkaline solutions (pH=7~14) or water etc. such as sodium carbonate, sodium hydroxide, imidazoles or ammoniacal liquor
Neutral solution, for nitrous acid in efficient absorption air and nitric acid gas；Liquid in second fluid reservoir is containing nitrous acid
The solution of salt and nitrate；Buffer solution in 3rd fluid reservoir can use the cushioning liquid such as phosphoric acid, carbonic acid, acetic acid, imidazoles,
To adjust absorbing liquid acid-base value (pH value)；Reaction solution in 4th fluid reservoir can use hydrochloric acid, P-aminobenzene-sulfonamide
With the mixed solution of N- (1- naphthyls)-ethylenediamine.
According to the present invention, the absorption tube can use spiral tube structure or straight type tubular construction；The helix tube caliber 1-
10mm, coiling diameter scope is 5-50mm, and length is 10-200mm；The straight type pipe caliber scope 1-100mm, length is 10-
200mm。
According to the present invention, the absorption tube external connection constant temperature water bath controls temperature by water circulation, and temperature range is
10-50℃。
According to the present invention, the safety flack can be using resistant materials such as glass, plastics, polytetrafluoroethylene (PTFE).
According to the present invention, the flow controller can use mass flowmenter, suspended body flowmeter, needle-valve or ratio electromagnetism
Valve, flow is 1 milliliter per minute to 100 Liter Per Minutes.
According to the present invention, the aspiration pump can use mechanical pump, membrane pump or piston pump, and the speed of evacuation is 1 milliliter every
Minute to 100 Liter Per Minutes.
According to the present invention, the conversion tube is that cadmium (Cd) converts post, is filled using 30-200 mesh particle size cadmiums pearl.
According to the present invention, the mixing chamber can be using inertia materials such as glass or quartz, and volume is 5 milliliters to 5 liters.
According to the present invention, the buffer pool can use coil pipe or helical pipe reactor, and material is glass, quartz, polytetrafluoro
Ethene (PTFE) or soluble poly tetrafluoroethene (PFA) etc..
According to the present invention, the light source can use Halogen lamp LED, LED or xenon lamp, and output wavelength scope is 200-1000nm.
According to the present invention, the absorption cell can use silica cuvette or liquid fiber absorption cell, and absorption light path is 1cm-
5m。
According to the present invention, the detector is diode or charge coupled cell (CCD) detector, is multi-channel detector,
Quantity is 1-10.
According to the present invention it is possible to add one or more liquid output pumps in pipeline as needed, it is easy to fluid flow
Control and preferably conveyed in pipeline.
According to the present invention, the liquid output pump can be one or more rear pump, and the multiple-channel output pump can have 4
To the output of 20 tunnels.For example, the multiple-channel output pump can be used for the output of the liquid of fluid reservoir.
According to the present invention, the liquid output pump can use peristaltic pump, high voltage and constant current infusion pump and micro syringe, stream
Measure per minute for 1 microlitre per minute to 100 milliliters.
The present invention also provides a kind of nitrous acid and concentration of nitric acid real-time online measuring method, and it uses above-mentioned on-line measurement
System, comprises the following steps：
(1) when thing to be detected is gas, with alkalescence or neutral absorbent solution by including nitrous acid and nitric acid gas
Gas is introduced in the form of a solution after absorbing, and is designated as solution C；When thing to be detected is nitrite or nitrate solution, it is introduced directly into,
It is designated as solution C '；
(2) it is nitrite by nitrate transformation, is then the absorbability thing with ultraviolet-visible by Nitrite transformation
Matter, carries out optical detection；
Wherein, by solution C or solution C ' it is divided into four tunnels, the first via passes through first turn in the first liquid phase chemical conversion unit
Change pipe, nitrate reduction is converted into nitrite, then by the second mixing chamber by Nitrite transformation be with ultraviolet-visible
Absorbent material carry out optical detection, obtain nitrite total concentration NAlways, HONO, the NAlways, HONO=system nitrite
Concentration NBody, HONOThe concentration N of the nitrite of nitrate transformation in+systemBody, HONO turns(it is equal to the concentration of nitrate in system
NBody, HNO3The total concentration N for the nitrite that)+impurity is converted intoMiscellaneous, HONO is total；
Second tunnel directly by the second mixing chamber in the first liquid-phase conversion unit, obtains impure nitrite concentration
NBody, HONO+ is miscellaneous, the NBody, HONO+ is miscellaneousThe concentration N of=system nitriteBody, HONOThe concentration for the nitrite that+impurity is converted into
NIt is miscellaneous, HONO；
3rd tunnel passes through the second conversion tube in second liquid phase chemical conversion unit, it would be possible to impurity be converted into nitrous acid
Salt, then by the 4th mixing chamber, Nitrite transformation is subjected to optical detection for the absorbent material with ultraviolet-visible, obtained
The total concentration N for the nitrite being converted into impurityMiscellaneous, HONO is total, the NMiscellaneous, HONO is totalThe nitrous acid of nitrate transformation in=impurity
The concentration N of saltMiscellaneous, HONO turns(it is equal to the concentration N of nitrate in impurityIt is miscellaneous, HNO3The concentration of the nitrite of)+impurity conversion production
NIt is miscellaneous, HONO；
4th tunnel directly by the 3rd mixing chamber of second liquid phase conversion unit, obtains the nitrite that impurity is converted into
Concentration NIt is miscellaneous, HONO；
Difference 1 by the second, the 4th tunnel measurement result is the concentration N for obtaining system nitriteBody, HONO；Pass through
First, the difference 2 of the 3rd tunnel measurement result further subtracts the concentration N that difference 1 obtains nitrate in systemBody, HNO3。
The beneficial effects of the invention are as follows：
1. the monitoring system is measured while can realizing to nitrous acid and nitric acid, while can also be disappeared by parallel channels
Except the interference of other gaseous substances.
2. the monitoring system can realize the trace detection to nitrous acid in air and nitric acid, and to nitrous acid in water body
Monitored with the trace of nitric acid, detection sensitivity is better than 10pptv (for nitrous acid) and 0.03 μ g/L (for nitric acid), during response
Between be less than 3-5min, the degree of accuracy ± (10%+10pptv) (for nitrous acid) and ± (10%+0.03 μ g/L) (for nitric acid).
3. the monitoring system both can be used for atmospheric environment, water body environment monitoring, experimental science research simultaneously can be used for
In terms of.
Brief description of the drawings
Fig. 1 is the nitrous acid of the present invention and the structural representation of concentration of nitric acid real-time online measuring system；
Wherein, 1. first aerosol filtration devices, 2. first fluid reservoir A, 3. first absorption tubes, 4. second absorption tubes, 5.
3rd fluid reservoir B, 6. safety flacks, 7. second aerosol filtration devices, 8. flow controllers, 9. aspiration pumps, 10. computers, 11.
Two conversion tubes, 12. the 4th fluid reservoir R, 13. first conversion tubes, 14. the 3rd mixing chambers, 15. the 4th mixing chambers, 16. first mixing
Room, 17. second mixing chambers, 18. second buffer pools, 19. first buffer pools, 20. light sources, 21. the 3rd absorption cells, 22. the 4th are inhaled
Receives pond, 23. second absorption cells, 24. first absorption cells, 25. detectors, 26. liquid output pumps, 27. permeable membrane devices, 28.
Two fluid reservoir S.
Fig. 2 introduces for a kind of of the 3rd fluid reservoir B in the nitrous acid and concentration of nitric acid real-time online measuring system of the present invention
Schematic diagram；
Wherein, 5. the 3rd fluid reservoir B.
Fig. 3 draws for the 3rd the another of fluid reservoir B in the nitrous acid and concentration of nitric acid real-time online measuring system of the present invention
Enter schematic diagram；
Wherein, 5. the 3rd fluid reservoir B.
Fig. 4 draws for another of the 3rd fluid reservoir B in the nitrous acid and concentration of nitric acid real-time online measuring system of the present invention
Enter schematic diagram；
Wherein, 5. the 3rd fluid reservoir B.
Embodiment
With reference to specific embodiment, the present invention is expanded on further.It should be understood that these embodiments are merely to illustrate the present invention
Rather than limitation the scope of the present invention.Furthermore, it is to be understood that after described content of the invention has been read, this area skill
Art personnel can make various changes or modifications to the present invention, and these equivalent form of values equally fall within limited range of the present invention.
Embodiment 1
A kind of nitrous acid and concentration of nitric acid real-time online measuring system, as shown in figure 1, the system includes what is be sequentially connected
External sample injection unit, liquid phase chemical conversion unit and optical absorption detection unit；External sample injection unit is entered for nitrogen-containing compound
Sample；It is nitrite that liquid phase chemical conversion unit, which is used for the nitrogen-containing compound sorption enhanced from external sample injection unit,；Optics
It is the absorbability thing with ultraviolet-visible that absorption detecting unit, which is used for the Nitrite transformation from liquid phase chemical conversion unit,
Matter, and carry out optical detection；
Described external sample injection unit includes gas phase sample injection unit and liquid-phase inlet unit；Carrying out gas phase nitrous acid and nitre
During acid concentration on-line checking, the 3rd two-port valve and the 4th two-port valve are closed, the first two-port valve and the second two-port valve is opened, then opens
Aspiration pump 9 is opened, the flow of flow controller 8 is set, constituent of atomsphere is pumped into from the front end of the first aerosol filtration device 1 and sampled
Component, is removed by particulate matter, and gaseous composition enters the first absorption tube 3 and the second absorption tube 4；At the same time, the first fluid reservoir
(A) absorbing liquid (neutral solution such as the alkaline solution such as sodium carbonate, sodium hydroxide, imidazoles or ammoniacal liquor (pH=7~14) or water) in 2
By liquid output pump control, a point two-way is respectively enterd in the first absorption cell 3 and the second absorption cell 4, is mutually mixed with gaseous composition
React, mainly absorb HONO therein and HNO3.The first outlet end of external sample injection unit and the conversion of the first liquid phase chemical
Unit is connected, and the second outlet end of external sample injection unit is connected with second liquid phase chemical conversion unit；Flow out first outlet
The liquid at end enters the first liquid phase chemical conversion unit, and the liquid at outflow second outlet end enters second liquid phase chemical conversion list
Member；The aerosol filtration device uses teflon membrane filter, and aperture is 0.2 μm.
First outlet end and second outlet end outflow liquid and the 3rd fluid reservoir (B) 5 in buffer solution (phosphoric acid, carbonic acid,
The cushioning liquid such as acetic acid, imidazoles) mixing, regulation liquid pH value to 7-10；As shown in Fig. 2 the mixing can be the 3rd liquid storage
The liquid that tank (B) 5 flows out can introduce the first liquid phase chemical conversion unit before the first and second port of export branches respectively
In second liquid phase chemical conversion unit；Or, as shown in figure 3, after the first and second port of export branches, being introduced between
Before the first mixing chamber 16 in first absorption circuit, first conversion circuit the first conversion tube 13 before, the second absorption circuit
In the 3rd mixing chamber 14 before, second conversion circuit the second conversion tube 11 before；Or, as shown in figure 4, one outlet end
It is incorporated into before branch in corresponding liquid phase chemical conversion unit, another port of export is introduced between pair after branch
Before mixing chamber in the absorption circuit answered, before the conversion tube of corresponding conversion circuit；
The first outlet end of buffer solution and the liquid at second outlet end being introduced into the 3rd fluid reservoir (B) 5 respectively enter
One liquid phase chemical conversion unit and second liquid phase chemical conversion unit, are directly mixed with the absorbing liquid in the 4th fluid reservoir (R) 12,
The mixing can be that the liquid of the 4th fluid reservoir (R) 12 outflow can be introduced between the first mixing in the first absorption circuit
Before room, first conversion circuit the first conversion tube and the second mixing chamber between, the 3rd mixing chamber in the second absorption circuit it
Before, second conversion circuit the second conversion tube and the 4th mixing chamber between；
For example, in the first absorption circuit, the liquid of first outlet end outflow is firstly introduced into the 3rd fluid reservoir (B) 5
Buffer solution, regulation liquid pH value to 7-10；It is subsequently introduced absorbing liquid (hydrochloric acid, sulfanilyl in the 4th fluid reservoir (R) 12
The mixed solution of amine and N- (1- naphthyls)-ethylenediamine), mixing reacts, and produces the material with visible absorption, then
It is sufficiently mixed into the first mixing chamber 16, and then enters the first absorption cell 23；In the first conversion circuit, the outflow of first outlet end
Liquid be firstly introduced into buffer solution in the 3rd fluid reservoir (B) 5, regulation liquid pH value to 7-10；Then pass through the first conversion tube
13, the nitrate anion in liquid is converted into nitrite ion, the absorbing liquid (salt in the 4th fluid reservoir (R) 12 is then re-introduced into
The mixed solution of acid, P-aminobenzene-sulfonamide and N- (1- naphthyls)-ethylenediamine), mixing reacts, and producing has visible ray
The material of absorption, subsequently enters the second mixing chamber 17 and is sufficiently mixed, and then enters the first buffer pool 19, finally enters the second absorption
Pond 24；
Similarly, in the second absorption circuit, the liquid of second outlet end outflow is firstly introduced into the 3rd fluid reservoir (B) 5
Buffer solution (imidazoles), regulation liquid pH value to 7-10；Be subsequently introduced in the 4th fluid reservoir (R) 12 absorbing liquid (hydrochloric acid, to amino
The mixed solution of benzsulfamide and N- (1- naphthyls)-ethylenediamine), mixing reacts, and produces the thing with visible absorption
Matter, subsequently enters the 3rd mixing chamber 14 and is sufficiently mixed, and then enters the 3rd absorption cell 21；In the second conversion circuit, second goes out
The liquid of mouth end outflow is firstly introduced into the buffer solution in the 3rd fluid reservoir (B) 5, regulation liquid pH value to 7-10；Then pass through
Two conversion tubes 11, nitrite ion is converted into by the nitrate anion in liquid, is then re-introduced into the suction in the 4th fluid reservoir (R) 12
Liquid (mixed solution of hydrochloric acid, P-aminobenzene-sulfonamide and N- (1- naphthyls)-ethylenediamine) is received, mixing reacts, generation has
The material of visible absorption, subsequently enters the 4th mixing chamber 15 and is sufficiently mixed, and then enters the second buffer pool 18, finally enters the
Four absorption cells 22；
The light that light source 20 is sent respectively enters four absorption cells 21,22,23,24 by four passages, by liquid absorption
Afterwards, remaining light intensity is detected by detector 25, and signal enters computer 10 and carries out data acquisition；
Wherein, the total concentration N of nitrite is obtained by absorption cell 24Always, HONO, the NAlways, HONO=system nitrite
Concentration NBody, HONOThe concentration N of the nitrite of nitrate transformation in+systemBody, HONO turns(it is equal to the concentration of nitrate in system
NBody, HNO3The total concentration N for the nitrite that)+impurity is converted intoMiscellaneous, HONO is total；
Impure nitrite concentration N is obtained by absorption cell 23Body, HONO+ is miscellaneous, the NBody, HONO+ is miscellaneousNitrous acid in=system
The concentration N of saltBody, HONOThe concentration N for the nitrite that+impurity is converted intoIt is miscellaneous, HONO；
The total concentration N for the nitrite that impurity is converted into can be obtained by absorption cell 22Miscellaneous, HONO is total, the NMiscellaneous, HONO is total
The concentration N of the nitrite of nitrate transformation in=impurityMiscellaneous, HONO turns(it is equal to the concentration N of nitrate in impurityIt is miscellaneous, HNO3)+impurity turns
The concentration N of the nitrite of metaplasia productionIt is miscellaneous, HONO；
The concentration N for the nitrite that impurity is converted into can be obtained by absorption cell 21It is miscellaneous, HONO；
Difference 1 by absorption cell 23, the measurement result of absorption cell 21 is the concentration N for obtaining system nitriteBody, HONO；
The concentration that difference 1 obtains nitrate in system is further subtracted by the difference 2 of absorption cell 24, the measurement result of absorption cell 22
NBody, HNO3。
In addition, computer 10 can control the intensity of light source 20, the switch of two-port valve is controlled, can also be by controlling liquid defeated
Go out Beng26Ge roads flow, realize the accurate control to absorbing liquid, buffer solution, reaction solution and four each fluid floies of absorbing path
System.
Fluid reservoir described in the present embodiment uses glass material.
Absorption tube uses spiral tube structure described in the present embodiment；The helix tube caliber 4-5mm, coiling diameter scope is
10-20mm, length is 10-200mm.
The constant temperature water bath of absorption tube external connection described in the present embodiment, temperature is controlled by water circulation, and temperature range is
25~35 DEG C.
Safety flack uses glass material described in the present embodiment.
Flow controller described in the present embodiment can use mass flowmenter, and range is 6 Liter Per Minutes.
Aspiration pump described in the present embodiment uses membrane pump, and the speed of evacuation is 5-6 Liter Per Minutes.
Conversion tube described in the present embodiment is that cadmium (Cd) converts post, is filled using 60-100 mesh particle size cadmiums pearl.
Mixing chamber described in the present embodiment uses polytetrafluoroethylene (PTFE) material, and volume is 3 liters.
Buffer pool described in the present embodiment can use coil pipe or helical pipe reactor, material be polytetrafluoroethylene (PTFE) (PTFE) and
Soluble poly tetrafluoroethene (PFA).
Light source described in the present embodiment uses xenon lamp, and output wavelength scope is 200-1000nm.
Absorption cell described in the present embodiment uses liquid fiber absorption cell, and absorption light path is 2.5m.
Detector described in the present embodiment is charge coupled cell (CCD) detector, is multi-channel detector, and quantity is 4.
One or more liquid output pumps can be added in the present embodiment in pipeline as needed, be easy to fluid flow control
Make and preferably conveyed in pipeline.
Liquid output pump described in the present embodiment can be one or more rear pump, and the multiple-channel output pump can have 4
To the output of 20 tunnels.For example, using 12 road rear pumps in the present embodiment, the multiple-channel output pump can be used for the liquid of fluid reservoir
Output.
Liquid output pump described in the present embodiment uses peristaltic pump, and rotating speed is 1-50 rpms, and flow is 100 micro-
Liter Per Minute to 2 milliliters it is per minute.
In the present embodiment, described absorption cell has four, wherein 21,22 two-way are control group, 23,24 two-way are experiment
Group, can continue to increase other absorption cell groups preferably to remove interference two groups of back as needed.Absorption cell group and follow-up
The configuration of detector is identical with existing system.
Embodiment 2
A kind of nitrous acid and concentration of nitric acid real-time online measuring system, as shown in figure 1, the system includes what is be sequentially connected
External sample injection unit, liquid phase chemical conversion unit and optical absorption detection unit；External sample injection unit is entered for nitrogen-containing compound
Sample；It is nitrite that liquid phase chemical conversion unit, which is used for the nitrogen-containing compound sorption enhanced from external sample injection unit,；Optics
It is the absorbability thing with ultraviolet-visible that absorption detecting unit, which is used for the Nitrite transformation from liquid phase chemical conversion unit,
Matter, and carry out optical detection；
Described external sample injection unit includes gas phase sample injection unit and liquid-phase inlet unit；Nitrous acid in liquid phase is carried out
When salt and nitrate concentration on-line checking, the 3rd two-port valve and the 4th two-port valve are opened, the first two-port valve and the second two-way is closed
Valve, by solution to be measured in the second fluid reservoir (S) 28 by liquid output pump control, point two-way is respectively by the first of external sample injection unit
The port of export and second outlet end output liquid, wherein, between the output liquid of second outlet end, it is additionally provided with permeable membrane device
27, for Water-soluble inorganic ions by using；
The first outlet end of external sample injection unit is connected with the first liquid phase chemical conversion unit, and the of external sample injection unit
Two ports of export are connected with second liquid phase chemical conversion unit；The liquid for flowing out first outlet end is converted into the first liquid phase chemical
Unit, the liquid at outflow second outlet end enters second liquid phase chemical conversion unit；
First outlet end and second outlet end outflow liquid and the 3rd fluid reservoir (B) 5 in buffer solution (phosphoric acid, carbonic acid,
The cushioning liquid such as acetic acid, imidazoles) mixing, regulation liquid pH value to 7-10；As shown in Fig. 2 the mixing can be the 3rd liquid storage
The liquid that tank (B) 5 flows out can introduce the first liquid phase chemical conversion unit before the first and second port of export branches respectively
In second liquid phase chemical conversion unit；Or, as shown in figure 3, after the first and second port of export branches, being introduced between
Before the first mixing chamber 16 in first absorption circuit, first conversion circuit the first conversion tube 13 before, the second absorption circuit
In the 3rd mixing chamber 14 before, second conversion circuit the second conversion tube 11 before；Or, as shown in figure 4, one outlet end
It is incorporated into before branch in corresponding liquid phase chemical conversion unit, another port of export is introduced between pair after branch
Before mixing chamber in the absorption circuit answered, before the conversion tube of corresponding conversion circuit；
The first outlet end of buffer solution and the liquid at second outlet end being introduced into the 3rd fluid reservoir (B) 5 respectively enter
One liquid phase chemical conversion unit and second liquid phase chemical conversion unit, are directly mixed with the absorbing liquid in the 4th fluid reservoir (R) 12,
The mixing can be that the liquid of the 4th fluid reservoir (R) 12 outflow can be introduced between the first mixing in the first absorption circuit
Before room, first conversion circuit the first conversion tube and the second mixing chamber between, the 3rd mixing chamber in the second absorption circuit it
Before, second conversion circuit the second conversion tube and the 4th mixing chamber between；
For example, in the first absorption circuit, the liquid of first outlet end outflow is firstly introduced into the 3rd fluid reservoir (B) 5
Buffer solution, regulation liquid pH value to 7-10；The absorbing liquid in the 4th fluid reservoir (R) 12 is subsequently introduced, mixes, reacts, is produced
The raw material with visible absorption, subsequently enters the first mixing chamber 16 and is sufficiently mixed, and then enters the first absorption cell 23；
In one conversion circuit, the liquid of first outlet end outflow is firstly introduced into the buffer solution in the 3rd fluid reservoir (B) 5, regulation liquid pH
It is worth to 7-10；The first conversion tube 13 is then passed through, the nitrate anion in liquid is converted into nitrite ion, is then re-introduced into
Absorbing liquid in four fluid reservoirs (R) 12, mixing, reacts, and produces the material with visible absorption, subsequently enters second and mixes
Close room 17 to be sufficiently mixed, and then enter the first buffer pool 19, finally enter the second absorption cell 24；
Similarly, in the second absorption circuit, the liquid of second outlet end outflow is firstly introduced into the 3rd fluid reservoir (B) 5
Buffer solution, regulation liquid pH value to 7-10；The absorbing liquid in the 4th fluid reservoir (R) 12 is subsequently introduced, mixes, reacts, is produced
The raw material with visible absorption, subsequently enters the 3rd mixing chamber 14 and is sufficiently mixed, and then enters the 3rd absorption cell 21；
In two conversion circuits, the liquid of second outlet end outflow is firstly introduced into the buffer solution in the 3rd fluid reservoir (B) 5, regulation liquid pH
It is worth to 7-10；The second conversion tube 11 is then passed through, the nitrate anion in liquid is converted into nitrite ion, is then re-introduced into
Absorbing liquid in four fluid reservoirs (R) 12, mixing, reacts, and produces the material with visible absorption, subsequently enters the 4th and mixes
Close room 15 to be sufficiently mixed, and then enter the second buffer pool 18, finally enter the 4th absorption cell 22；
The light that light source 20 is sent respectively enters four absorption cells 21,22,23,24 by four passages, by liquid absorption
Afterwards, remaining light intensity is detected by detector 25, and signal enters computer 10 and carries out data acquisition；
Wherein, the total concentration N of nitrite is obtained by absorption cell 24Always, HONO, the NAlways, HONO=system nitrite
Concentration NBody, HONOThe concentration N of the nitrite of nitrate transformation in+systemBody, HONO turns(it is equal to the concentration of nitrate in system
NBody, HNO3The total concentration N for the nitrite that)+impurity is converted intoMiscellaneous, HONO is total；
Impure nitrite concentration N is obtained by absorption cell 23Body, HONO+ is miscellaneous, the NBody, HONO+ is miscellaneousNitrous acid in=system
The concentration N of saltBody, HONOThe concentration N for the nitrite that+impurity is converted intoIt is miscellaneous, HONO；
The total concentration N for the nitrite that impurity is converted into can be obtained by absorption cell 22Miscellaneous, HONO is total, the NMiscellaneous, HONO is total
The concentration N of the nitrite of nitrate transformation in=impurityMiscellaneous, HONO turns(it is equal to the concentration N of nitrate in impurityIt is miscellaneous, HNO3)+impurity turns
The concentration N of the nitrite of metaplasia productionIt is miscellaneous, HONO；
The concentration N for the nitrite that impurity is converted into can be obtained by absorption cell 21It is miscellaneous, HONO；
Difference 1 by absorption cell 23, the measurement result of absorption cell 21 is the concentration N for obtaining system nitriteBody, HONO；
The concentration that difference 1 obtains nitrate in system is further subtracted by the difference 2 of absorption cell 24, the measurement result of absorption cell 22
NBody, HNO3。
In addition, computer 10 can control the intensity of light source 20, the switch of two-port valve is controlled, can also be by controlling liquid defeated
Go out Beng26Ge roads flow, realize the accurate control to absorbing liquid, buffer solution, reaction solution and four each fluid floies of absorbing path
System.
In the present embodiment, described absorption cell has four, wherein 21,22 two-way are control group, 23,24 two-way are experiment
Group, can continue to increase other absorption cell groups preferably to remove interference two groups of back as needed.Absorption cell group and follow-up
The configuration of detector is identical with existing system.
In the present embodiment, the control of selection and flow for the part, if without specified otherwise, be the same as Example 1.
The present invention two embodiments more than can realize in air nitrous in nitrous acid and concentration of nitric acid, liquid phase respectively
The real-time online measuring of hydrochlorate and nitrate concentration, detection can be respectively reached by changing gas liquid flow velocity and optical path length
Sensitivity be better than 10pptv (for nitrous acid) and 0.03 μ g/L (for nitric acid), the response time be less than 3-5min, the degree of accuracy ±
(10%+10pptv) (for nitrous acid) and ± (10%+0.03 μ g/L) (for nitric acid).
More than, embodiments of the present invention are illustrated.But, the present invention is not limited to above-mentioned embodiment.It is all
Within the spirit and principles in the present invention, any modification, equivalent substitution and improvements done etc., should be included in the guarantor of the present invention
Within the scope of shield.
Claims (10)
1. a kind of nitrous acid and concentration of nitric acid real-time online measuring system, it is characterised in that the system includes what is be sequentially connected
External sample injection unit, liquid phase chemical conversion unit and optical absorption detection unit；External sample injection unit is entered for nitrogen-containing compound
Sample；It is nitrite that liquid phase chemical conversion unit, which is used for the nitrogen-containing compound sorption enhanced from external sample injection unit,；Optics
It is the absorbability thing with ultraviolet-visible that absorption detecting unit, which is used for the Nitrite transformation from liquid phase chemical conversion unit,
Matter, and carry out optical detection；
The liquid phase chemical conversion unit includes the first liquid phase chemical conversion unit and second liquid phase chemical conversion unit；
The optical absorption detection unit includes the first optical absorption detection unit and the second optical absorption detection unit；
In the external sample injection unit, nitrous acid and nitric acid to be detected is connected with the entrance point of the external sample injection unit, outside
Putting sample injection unit includes two ports of export, is designated as first outlet end and second outlet end, is converted respectively with the first liquid phase chemical single
Member and the connection of second liquid phase chemical conversion unit；
The rear end of first liquid phase chemical conversion unit is connected with the first optical absorption detection unit, second liquid phase chemical conversion unit
Rear end be connected with the second optical absorption detection unit；Second optical absorption detection unit can only obtain the Asia that impurity is converted into
The concentration of nitrate and nitrate, and it is used as background deduction；First optical absorption detection unit can in acquisition system and
Nitrite and the concentration of nitrate that impurity is converted into, by the background deduction for deducting the second optical absorption detection unit
, that is, obtain the concentration of system nitrite and nitrate.
2. system according to claim 1, it is characterised in that described external sample injection unit include gas phase sample injection unit and
Liquid-phase inlet unit.
Preferably, described gas phase sample injection unit includes gas absorbing device, and the gas absorbing device includes the first aerosol
Filter (1), the first absorption tube (3), the second absorption tube (4), the first fluid reservoir (A) (2) and two two-port valves；Described first
Aerosol filtration device (1) is connected with the first absorption tube (3), and first absorption tube (3) is connected with the second absorption tube (4)；Institute
The first liquid outlet for stating the first fluid reservoir (A) (2) is connected with the first absorption tube (3)；The second of first fluid reservoir (A) (2)
Liquid outlet is connected with the second absorption tube (4)；First absorption tube (3) is connected by the first two-port valve with first outlet end, institute
The second absorption tube (4) is stated to be connected with second outlet end by the second two-port valve.
Preferably, described gas phase sample injection unit also includes air extractor, and the air extractor includes aspiration pump (9), gas stream
Amount controller (8), the second aerosol filtration device (7) and safety flack (6)；The aspiration pump (9) and gas flow controller (8)
It is connected, the gas flow controller (8) is connected with the second aerosol filtration device (7), the second aerosol filtration device
(7) it is connected with safety flack (6)；The safety flack (6) is connected with the second absorption tube (4) in gas absorbing device.
Preferably, described liquid-phase inlet unit includes the second fluid reservoir (S) (28) and permeable membrane device (27), second storage
Flow container (S) (28) sets two liquid outlets, is designated as the 3rd liquid outlet and the 4th liquid outlet；3rd liquid outlet passes through the three or two
Port valve is connected with first outlet end, and the 4th liquid outlet is connected with the entrance of the permeable membrane device (27), the permeable membrane
The outlet of device (27) is connected by the 4th two-port valve with second outlet end.
3. system according to claim 1 or 2, it is characterised in that the first liquid phase chemical conversion unit includes first
Absorption circuit and the first conversion circuit；First absorption circuit includes the first mixing chamber (16), first mixing chamber (16)
Outlet be connected with optical absorption detection unit；
The first conversion circuit includes the first conversion tube (13), the second mixing chamber (17) and the first buffer pool (19), described the
The outlet of one conversion tube (13) is connected with the entrance of second mixing chamber (17)；The outlet of second mixing chamber (17) and institute
The entrance for stating the first buffer pool (19) is connected；The outlet of first buffer pool (19) is connected with optical absorption detection unit；
The first liquid phase chemical conversion unit is connected with first outlet end, and the first outlet end is divided into two-way, all the way with
The entrance of the first mixing chamber (16) in one absorption circuit is connected, another road and the first conversion tube (13) phase of the first conversion circuit
Even.
Preferably, the second liquid phase chemical conversion unit includes the second absorption circuit and the second conversion circuit；Described second inhales
Take-up road includes the 3rd mixing chamber (14), and the outlet of the 3rd mixing chamber (14) is connected with optical absorption detection unit；
The second conversion circuit includes the second conversion tube (11), the 4th mixing chamber (15) and the second buffer pool (18), described the
The outlet of two conversion tubes (11) is connected with the entrance of the 4th mixing chamber (15)；The outlet of 4th mixing chamber (15) and institute
The entrance for stating the second buffer pool (18) is connected；The outlet of second buffer pool (18) is connected with optical absorption detection unit；
The second liquid phase chemical conversion unit is connected with second outlet end, and the second outlet end is divided into two-way, all the way with
The entrance of the 3rd mixing chamber (14) in two absorption circuits is connected, another road and the second conversion tube (11) phase of the second conversion circuit
Even.
4. the system according to any one of claim 1-3, it is characterised in that the liquid phase chemical conversion unit also enters one
Step includes the 3rd fluid reservoir (B) (5)；The liquid of 3rd fluid reservoir (B) (5) respectively the first and second port of export branches it
Before be incorporated into the first liquid phase chemical conversion unit and second liquid phase chemical conversion unit；Or, in first and second ports of export
After branch, before being introduced between the first mixing chamber (16) in the first absorption circuit, the first conversion of the first conversion circuit
Manage (13) before, before the 3rd mixing chamber (14) in the second absorption circuit, second conversion circuit the second conversion tube (11) it
Before；The either combination of above two incorporation way.
Preferably, the liquid phase chemical conversion unit still further comprises the 4th fluid reservoir (R) (12), the 4th fluid reservoir
(R) before the liquid of (12) is introduced between the first mixing chamber (16) in the first absorption circuit, the first of the first conversion circuit
Before the 3rd mixing chamber (14) between conversion tube (13) and the second mixing chamber (17), in the second absorption circuit, the second transition lines
Between second conversion tube (11) and the 4th mixing chamber (15) on road.
5. the system according to any one of claim 1-4, it is characterised in that the optical absorption detection unit includes four
Individual optical absorption detection unit, light source (20) and detector (25)；The first optical absorption detection unit includes first and absorbed
Pond (23), the outlet of the first mixing chamber (16) is connected with the entrance of the first absorption cell (23)；The second optical absorption detection is single
Member includes the second absorption cell (24), and the outlet of first buffer pool (19) is connected with the entrance of the second absorption cell (24)；It is described
3rd optical absorption detection unit includes the 3rd absorption cell (21), outlet and the 3rd absorption cell (21) of the 3rd mixing chamber (14)
Entrance is connected；The 4th optical absorption detection unit includes the 4th absorption cell (22), the outlet of second buffer pool (18)
It is connected with the entrance of the 4th absorption cell (22)；Entrance of the light source respectively with four absorption cells is connected, the detector difference
Outlet with four absorption cells is connected.
6. the system according to any one of claim 1-5, it is characterised in that the system also includes further eliminating dry
Disturb one or more parallel channels of material influence, each parallel channels include absorption tube, conversion tube, two
Absorption tube, conversion tube, absorption cell, infusion pump and detector in absorption cell, infusion pump, light source and detector, parallel channels
Connected mode it is identical with the connection of corresponding component and the method for operation in liquid phase chemical conversion unit and optical absorption detection unit.
If multiple parallel channels, the absorption tube in the multiple parallel channels is connected with the absorption tube of previous parallel channels.
7. the system according to any one of claim 1-6, it is characterised in that the on-line monitoring system also includes computer
Control unit, for controlling the intensity of light source, the uninterrupted of flow controller, the output flow of infusion pump and acquisition testing device
Detection data.
8. the system according to any one of claim 1-7, it is characterised in that the first aerosol filtration device and
Two aerosol filtration devices are using filter membrane or collision removal system；The filter membrane material can elect quartz, glass fibre or poly- as
One or more in tetrafluoroethene, the pore diameter range of filter membrane is 0.002-100 μm.
Preferably, the fluid reservoir can be used in the resistant materials such as glass, plastics, polytetrafluoroethylene (PTFE), first fluid reservoir
Absorbing liquid can be neutral molten using the alkaline solution (pH=7~14) or water etc. such as sodium carbonate, sodium hydroxide, imidazoles or ammoniacal liquor
Liquid, for nitrous acid in efficient absorption air and nitric acid gas；Liquid in second fluid reservoir is containing nitrite and nitre
The solution of hydrochlorate；Buffer solution in 3rd fluid reservoir can be using cushioning liquid such as phosphoric acid, carbonic acid, acetic acid, imidazoles, to adjust
Save absorbing liquid acid-base value (pH value)；Reaction solution in 4th fluid reservoir can use hydrochloric acid, P-aminobenzene-sulfonamide and N- (1-
Naphthyl)-ethylenediamine mixed solution.
Preferably, the absorption tube can use spiral tube structure or straight type tubular construction；The helix tube caliber 1-10mm, winding
Diameter range is 5-50mm, and length is 10-200mm；The straight type pipe caliber scope 1-100mm, length is 10-200mm.
Preferably, the absorption tube external connection constant temperature water bath, temperature is controlled by water circulation, and temperature range is 10-50 DEG C.
Preferably, the safety flack can be using resistant materials such as glass, plastics, polytetrafluoroethylene (PTFE).
9. the system according to any one of claim 1-8, it is characterised in that the flow controller can use quality
Flowmeter, suspended body flowmeter, needle-valve or proportion magnetic valve, flow are 1 milliliter per minute to 100 Liter Per Minutes.
Preferably, the aspiration pump can use mechanical pump, membrane pump or piston pump, and the speed of evacuation is 1 milliliter per minute to 100
Liter Per Minute.
Preferably, the conversion tube is that cadmium (Cd) converts post, is filled using 30-200 mesh particle size cadmiums pearl.
Preferably, the mixing chamber can be using inertia materials such as glass or quartz, and volume is 5 milliliters to 5 liters.
Preferably, the buffer pool can use coil pipe or helical pipe reactor, and material is glass, quartz, polytetrafluoroethylene (PTFE)
Or soluble poly tetrafluoroethene (PFA) etc. (PTFE).
Preferably, the light source can use Halogen lamp LED, LED or xenon lamp, and output wavelength scope is 200-1000nm.
Preferably, the absorption cell can use silica cuvette or liquid fiber absorption cell, and absorption light path is 1cm-5m.
Preferably, the detector is diode or charge coupled cell (CCD) detector, is multi-channel detector, quantity is 1-
10.
Preferably, one or more liquid output pumps can be added in pipeline as needed, be easy to fluid flow control and
Preferably conveyed in pipeline.
Preferably, the liquid output pump can be one or more rear pump, and the multiple-channel output pump can have 4 to 20 roads defeated
Go out.For example, the multiple-channel output pump can be used for the output of the liquid of fluid reservoir.
Preferably, the liquid output pump can use peristaltic pump, high voltage and constant current infusion pump and micro syringe, and flow is 1 micro-
Liter Per Minute to 100 milliliters it is per minute.
10. a kind of nitrous acid and concentration of nitric acid real-time online measuring method, it is characterised in that methods described uses claim 1-
On-line measurement system described in 9 any one, comprises the following steps：
(1) when thing to be detected is gas, with alkalescence or neutral absorbent solution by the gas including nitrous acid and nitric acid gas
Introduced in the form of a solution after absorption, be designated as solution C；When thing to be detected is nitrite or nitrate solution, it is introduced directly into, is designated as
Solution C '；
(2) it is nitrite by nitrate transformation, is then the absorbent material with ultraviolet-visible by Nitrite transformation,
Carry out optical detection；
Wherein, by solution C or solution C ' it is divided into four tunnels, the first via passes through the first conversion in the first liquid phase chemical conversion unit
Pipe, nitrite is converted into by nitrate reduction, then by the second mixing chamber by Nitrite transformation is with ultraviolet-visible
Absorbent material carries out optical detection, obtains the total concentration N of nitriteAlways, HONO, the NAlways, HONO=system nitrite
Concentration NBody, HONOThe concentration N of the nitrite of nitrate transformation in+systemBody, HONO turns(it is equal to the concentration of nitrate in system
NBody, HNO3The total concentration N for the nitrite that)+impurity is converted intoMiscellaneous, HONO is total；
Second tunnel directly by the second mixing chamber in the first liquid-phase conversion unit, obtains impure nitrite concentration
NBody, HONO+ is miscellaneous, the NBody, HONO+ is miscellaneousThe concentration N of=system nitriteBody, HONOThe concentration for the nitrite that+impurity is converted into
NIt is miscellaneous, HONO；
3rd tunnel passes through the second conversion tube in second liquid phase chemical conversion unit, it would be possible to impurity be converted into nitrite,
Again by the 4th mixing chamber, Nitrite transformation is subjected to optical detection for the absorbent material with ultraviolet-visible, obtains miscellaneous
The total concentration N for the nitrite that matter is converted intoMiscellaneous, HONO is total, the NMiscellaneous, HONO is totalThe nitrite of nitrate transformation in=impurity
Concentration NMiscellaneous, HONO turns(it is equal to the concentration N of nitrate in impurityIt is miscellaneous, HNO3The concentration N of the nitrite of)+impurity conversion productionIt is miscellaneous, HONO；
4th tunnel directly by the 3rd mixing chamber of second liquid phase conversion unit, obtains the dense of the nitrite that impurity is converted into
Spend NIt is miscellaneous, HONO；
Difference 1 by the second, the 4th tunnel measurement result is the concentration N for obtaining system nitriteBody, HONO；Pass through first,
The difference 2 of three tunnel measurement results further subtracts the concentration N that difference 1 obtains nitrate in systemBody, HNO3。
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| CN112666305A (en) * | 2020-12-07 | 2021-04-16 | 吉林建筑大学 | Method for monitoring flux of volatile gas released in wet sedimentation evaporation process |
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| CN107064029B (en) | 2023-10-17 |
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