CN100561211C - A method and device for detecting ammonia - Google Patents

Abstract

The invention relates to an ammonia detection method and device, which utilizes the principle that the ammonium root can be completely converted into ammonia gas in an aqueous solution with a pH ≥ 12.3, reacts the ammonium root solution with a strong base to generate ammonia gas, and sets it in a semipermeable The secondary water on the other side of the membrane captures and absorbs ammonia gas, and by measuring the change of the conductivity value after the secondary water absorbs ammonia gas, the concentration of the original ammonium radical derivatized can be determined. The device of the present invention comprises a controllable thermostat, a detection module arranged in the thermostat, a conductance electrode connected to the detection module, a signal collector connected to the conductance electrode, and a computer connected to the signal collector ; The detection module includes two parts, an upper module and a lower module connected together by bolts. The development of the method and device of the invention is based on the atmospheric environment, and can measure the ammonia component concentration in the gas and aerosol respectively, but it is also applicable to the water environment, and can realize online measurement.

Description

A method and device for detecting ammonia

technical field

The invention relates to a detection method and a device, in particular to an ammonia detection method and a device which use the change of the conductance value of secondary water (deionized water) to derivate the original ammonium root concentration.

Background technique

At present, the commonly used method for measuring the concentration of ammonium ions in aqueous solution is to use ion chromatography. Ion chromatography has the advantages of fast, sensitive, good selectivity and simultaneous determination of multiple components. However, cation chromatography is expensive, bulky, and leaching The water consumption of liquid and regeneration liquid is large, and the calibration time is long; if online measurement is to be realized, it is difficult to combine with the acquisition system.

Contents of the invention

In view of the above problems, the object of the present invention is to provide an ammonia detection method and device that is small in size, easy to carry, transparent and visible, simple in calibration method, and suitable for online observation outside the laboratory.

In order to achieve the above object, the present invention adopts the following technical solutions: a method for detecting ammonia, which uses the principle that the ammonium root can be completely converted into ammonia gas in an aqueous solution with a pH ≥ 12.3, and reacts the ammonium root solution with a strong base to generate ammonia The ammonia gas is collected and absorbed by the secondary water set on the other side of the semi-permeable membrane, and the change of the conductivity value after the secondary water absorbs the ammonia gas is measured to realize the determination of the original ammonium root concentration derivatized.

An ammonia detection device for realizing the above method, characterized in that: it includes a controllable thermostatic box, a detection module arranged in the thermostatic box, a conductance electrode connected to the detection module, and a signal acquisition unit connected to the conductance electrode device, and a computer connected to the signal collector; the detection module includes two parts, an upper module and a lower module connected together by bolts: a stabilizing column and a deionization column are arranged in the upper module, and the upper module The bottom surface of the module is provided with an absorption tank, the outlet end of the flow stabilization column is connected to the inlet end of the deionization column, the outlet end of the deionization column is connected to the inlet end of the absorption tank through a chute, and the absorption The outlet end of the tank is connected to a conductivity cell, one interface of the conductivity cell is connected to a liquid discharge pipe, and the other two interfaces are respectively connected to the positive and negative poles of the conductivity electrode; two stabilizing columns are arranged in the lower module, so that The top surface of the lower module is longitudinally provided with a reaction tank, and one end of the two stabilizing columns is respectively connected to the inlet of the reaction tank through a chute; the outlet of the reaction tank is connected to a waste liquid discharge pipe; the semi-permeable membrane, It is arranged between the upper module and the lower module.

An electric heater, an electric fan, a temperature sensor and a temperature adjustment control device are arranged in the thermostatic box, the electric fan is arranged at the air inlet of the thermostatic box, the electric heater is a resistance wire, and the temperature sensor Set near the conductance cell, the electric heater, electric fan, and temperature sensor are respectively connected to the temperature adjustment control device.

One of the two stabilizing columns of the lower module is connected to the sodium hydroxide solution through a liquid pump, and the other is connected to the ammonium sample solution through another liquid pump, and the stabilizing column of the upper module is connected to the secondary water through another liquid pump, so The deionization column of the above-mentioned upper module is filled with deionization resin.

The liquid pump is a peristaltic pump.

The present invention has the following advantages due to the adoption of the above technical scheme: 1. The inventive method utilizes the principle that the ammonium root can all be converted into ammonia in the aqueous solution of PH >= 12.3, absorbs ammonia with secondary water, and utilizes secondary water The change of the conductivity value realizes the determination of the original ammonium root concentration derivatized, not only the collection method is simple, but also the measurement accuracy is high. 2. The detection system of the present invention is composed of two modules. Through the processing of the two modules, a steady flow column, a deionization column, a reaction tank, an absorption tank, and various pipeline passages are formed, so that the detection system is very simple and the cost is low. 3. The flow stabilizing column set in the system of the present invention can stabilize the liquid flow during operation, remove the interference of air bubbles, and maintain a stable baseline; the deionization column can further stabilize the conductance of the background baseline during operation and improve detection sensitivity. 4. Since the present invention adopts a controllable constant temperature box to replace the traditional temperature compensation method, the temperature accuracy can be controlled at ±0.1°C, making the measurement data more stable and reliable. 5. The device of the present invention mainly uses common plexiglass blocks and conventional detection components, so the source of materials is abundant and the overall cost is low. The development of the method and device of the invention is based on the atmospheric environment, and can measure the ammonia component concentration in the gas and aerosol respectively, but it is also applicable to the water environment, and can realize online measurement.

Description of drawings

Fig. 1 is a schematic diagram of the overall structure of the device of the present invention

Fig. 2 is a schematic diagram of the three-dimensional structure of the detection module of the present invention

Fig. 3 is a structural schematic diagram of the lower module of the present invention

Figure 4 is a schematic left view of Figure 3

Figure 5 is a schematic top view of Figure 3

Fig. 6 is a structural schematic diagram of the upper module of the present invention

Figure 7 is a schematic left view of Figure 7

Figure 8 is a schematic top view of Figure 7

Fig. 9 schematic diagram of working principle of the present invention

Detailed ways

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

The method of the present invention utilizes in the aqueous solution of pH ≥ 12.3, utilizes in the aqueous solution of PH ≥ 12.3, the principle that the ammonium root can be completely converted into ammonia gas, reacts the ammonium root solution with a strong base to generate ammonia gas, and passes through the semi-permeable membrane The secondary water on the other side traps and absorbs the ammonia gas, and by measuring the change of the conductivity value after the secondary water absorbs the ammonia gas, the determination of the original ammonium root concentration derivatized is realized.

As shown in Fig. 1 and Fig. 2, the device of the present invention comprises a controllable incubator 1, and a detection module 2 is arranged in the incubator 1, and the detection module 2 includes an upper module 3 and a lower module 4 which are integrally connected by bolts, and the upper module 1. A semi-permeable membrane 5 that allows gas to pass through but does not allow liquid to pass is arranged between the lower modules 3 and 4; a conductance electrode 6 connected to the detection module 2, a signal collector 7 connected to the conductance electrode 6, and a signal collector connected 7 for the computer 8. Device of the present invention also comprises three liquid pumps 9,10,11 and three containers that secondary water 12, ammonium sample solution 13 and sodium hydroxide solution 14 are equipped with, and electric fan 15, electric heater 16, temperature sensor 17 And temperature adjustment control device 18.

As shown in FIGS. 2 to 5 , two column holes extending longitudinally are arranged inside the upper part 3 of the module, one as a stabilizing column 31 and the other as a deionization column 32 . An absorption groove 33 is vertically arranged on the bottom surface of the upper module 3, and a V-shaped groove 34 (V-shaped groove is for convenience of processing, but not limited to this) is connected to the inlet end of the deionization column 32 at the outlet end of the flow stabilization column 31, The outlet end of the deionization column 32 is connected to the inlet end of the absorption tank 33 through a chute 35, and the outlet end of the absorption tank 33 is connected to a conductivity cell 36, and an interface 361 in the middle of the three interfaces of the conductivity cell 36 is connected to the liquid discharge pipe 19 ( As shown in FIG. 1 ), the two interfaces 362 and 363 on both sides are respectively connected to the positive and negative poles of the conductance electrode 6 . The deionization resin is filled in the deionization column 32 to stabilize the background conductance in the deionization water, so that the background baseline is more stable, thereby improving the detection sensitivity. As shown in FIG. 3 , a plurality of bolt mounting holes 37 for connecting the lower module 4 are provided on the edge of the upper module 3 .

As shown in Figure 2 and Figures 6-8, the interior of the lower module 4 is also provided with two longitudinally extending column holes, both of which are used as stabilizing columns 41, 42; The reaction tank 43 corresponding to the adsorption tank 33, the inlet end of the reaction tank 43 is connected to the inlet ends of the two stabilizing columns 41, 42 through two downwardly inclined chute 44, 45, and the outlet end 46 of the reaction tank 43 is connected to a waste liquid Discharge pipe 20 (as shown in FIG. 1 ). As shown in FIG. 6 , a plurality of bolt installation holes 47 corresponding to the positions of the bolt installation holes 37 of the upper module 3 are provided on the edge of the lower module 4 .

As shown in Figure 9, when the present invention works, under the effect of peristaltic pump 11, sodium hydroxide solution 14 enters in the steady flow column 41 of lower module 4, and under the effect of peristaltic pump 10, ammonium sample solution 13 enters lower module In the steady flow column 42 of 4, the sodium hydroxide solution 14 and the ammonium sample solution 13 are collected and reacted in the reaction tank 43 through the chute 44,45 respectively, and the ammonium radicals in the ammonium sample solution 13 are all converted into ammonia gas, and the ammonia gas Penetrate the semi-permeable membrane 5 into the upper module 3, while the liquid cannot pass through the semi-permeable membrane 5. Under the action of the peristaltic pump 9, the secondary water 12 enters the absorption tank 33 after passing through the steady flow column 31 and the deionization column 32 of the upper module 3 in sequence, and the deionized secondary water 12 absorbs the ammonia gas passing through the semipermeable membrane 5, The aqueous solution containing ammonium ions enters the conductivity cell 36, and after the data of the conductivity value is tested by the conductivity electrode 6, it is discharged through the waste liquid pipe 19. The signal collector 7 inputs the measured conductance value data into the computer 8 for analysis and processing, and can convert the conductance value to obtain the ammonium root concentration.

As shown in Figure 1, the constant temperature box 1 utilizes the resistance wire as the electric heater 16 to heat, and the air in the constant temperature box 1 is stirred by the electric fan 15 arranged at the air inlet of the constant temperature box, so that the heat is evenly distributed, and the heat is passed through the constant temperature box 1 The temperature sensor 17 installed inside transmits the temperature signal to the external temperature adjustment control device 18, and the electric heater 16 and the electric fan 15 are also electrically connected to the temperature adjustment control device 18, so as to achieve the purpose of constant temperature. The device of the present invention can work at a constant temperature of 35°C-40°C, and the temperature control range of the temperature adjustment control device 18 can also be changed to adapt to different test situations. The temperature sensor 17 can be installed near the conductance cell 36, and the conductance electrode 6 is connected to the signal collector 7 arranged outside the incubator 2, and the conductance signal is continuously collected and input to the computer 8 for processing.

Claims (5)

1, a kind of ammonia detecting device is characterized in that: it comprises a controllable thermostat, is arranged on the detection module in described thermostat, connects the conductance electrode of described detection module, connects the signal collector of described conductance electrode, And the computer connected to the signal collector; the detection module includes two parts: an upper module and a lower module connected together by bolts: A flow stabilization column and a deionization column are arranged in the upper module, an absorption tank is arranged on the bottom surface of the upper module, the outlet end of the flow stabilization column is connected to the inlet end of the deionization column, and the deionization column The outlet end of the absorption tank is connected to the inlet end of the absorption tank through a chute, the outlet end of the absorption tank is connected to a conductivity cell, one interface of the conductivity cell is connected to a liquid discharge pipe, and the other two interfaces are respectively connected to the conductivity cell. The positive and negative poles of the electrodes; The lower module is provided with two stabilizing columns, and the top surface of the lower module is longitudinally provided with a reaction tank, and one end of the two stabilizing columns is respectively connected to the entrance of the reaction tank through a chute; the reaction tank The outlet of the outlet is connected to a waste liquid discharge pipe; a semi-permeable membrane disposed between the upper module and the lower module. 2. An ammonia detection device according to claim 1, characterized in that: an electric heater, an electric fan, a temperature sensor, and a temperature adjustment control device are arranged in the thermostatic box, and the electric fan is arranged in the thermostat At the air inlet of the box, the electric heater is a resistance wire, the temperature sensor is arranged near the conductivity cell, and the electric heater, electric fan, and temperature sensor are respectively connected to the temperature adjustment control device. 3. An ammonia detection device according to claim 1, characterized in that: one of the two stabilizing columns of the lower module is connected to the sodium hydroxide solution through a liquid pump, and the other is connected to the ammonium sample solution through another liquid pump, The steady flow column of the upper module is connected with secondary water through another liquid pump, and the deionization column of the upper module is filled with deionization resin. 4. An ammonia detection device according to claim 2, characterized in that: one of the two stabilizing columns of the lower module is connected to the sodium hydroxide solution through a liquid pump, and the other is connected to the ammonium sample solution through another liquid pump, The steady flow column of the upper module is connected with secondary water through another liquid pump, and the deionization column of the upper module is filled with deionization resin. 5. An ammonia detection device according to claim 3 or 4, characterized in that the liquid pump is a peristaltic pump.

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