JPS5848845A - Measuring method of sulfuric ion density - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring the concentration of sulfur ions (S) in a liquid to be measured, and more specifically, to a method for measuring the concentration of sulfur ions (S) in a liquid to be measured. By directly measuring the concentration of hydrogen sulfide in the gas phase with a hydrogen sulfide detector, contact between the liquid to be measured and the detector is eliminated, and contamination of the detector by the liquid to be measured is prevented. The present invention relates to a method for measuring sulfur ion concentration in a liquid to be measured.

Due to the concentration of population in cities and the development of industry, the quality of environmental water and industrial wastewater is deteriorating, and the concentration of dissolved hydrogen sulfide is increasing. Hydrogen sulfide is a substance that causes bad odors, and continuous measurement of its concentration is important in terms of water pollution.

Conventionally, hydrogen sulfide or sulfur ions (S2
-) The methylene blue method and the sulfur ion electrode method are known as methods for measuring concentration, but if the device is to be used for automatic analysis, the ion electrode method uses a sulfur ion electrode as a sensor due to its ease of handling. has been widely adopted. This method directly measures the sulfur ion concentration by immersing a sulfur ion electrode and a reference electrode in a sample solution made of a predetermined strongly alkaline PI (2), which ensures long-term continuous operation (2). In order to do this, it is necessary to install auxiliary equipment such as glaze, which makes the entire system larger and more complex, leading to various troubles and increased manufacturing costs.For example, the liquid to be measured is usually sludge or oil. , surfactants and other substances, the 'r1 pole part is likely to be contaminated by these substances, and when conducting long-term continuous measurements, it is necessary to check the contamination in the liquid to be measured in advance. A P paper filter is essential to remove substances. However, if the liquid to be measured is extremely contaminated, the filter may become clogged and the liquid to be measured may be sent to the constant part 611). In addition, even if the filter is used to remove contaminants from the liquid to be measured, the response time may become longer due to dirt on the electrode, and the reading error may become large. Since the electrodes get dirty, it is necessary to have an automatic cleaning device that cleans the electrodes periodically.This automatic cleaning device uses a method that cleans with chemicals such as acid, and a method that mechanically polishes the contaminated electrode film. However, in the former case, there remains the problem of after-treatment of hydrochloric acid, nitric acid, etc. used for cleaning. Water generates chlorine gas, which alters the sensitive elements of the electrodes and causes reading errors on the meter, so tap water cannot be used. Always have pure water available to clean the stained electrodes. However, maintenance is difficult.

In addition, in the latter case of cleaning by mechanical polishing, polishing the electrode film causes the electrode potential for a constant sulfur ion concentration to fluctuate, causing measurement errors, so it is necessary to automatically calibrate each polishing. However, this increases the complexity of the device. Furthermore, if the liquid to be measured contains oil or surfactant,
In these cases, the sulfur ion electrode itself ceases to function, so the sulfur ion electrode method is applicable to these liquids in many countries. Furthermore, the sulfur ion electrode is
Although a comparison electrode is required as a pole, there is a problem in that a 611'' error occurs due to the generation of a liquid junction potential due to contamination of the liquid junction of this comparison electrode.

Furthermore, the concentration of sulfur ions (s) in the liquid to be measured is pl(
Also, since the sulfur ion electrode only responds to sulfur ions (s 2- ), the PL of the liquid to be measured must always be kept constant. In addition to its complicated control, IC yellow ion 71';
There are also problems such as the linear area of the polar cross-section line being narrow.

The present invention has been made to improve the above-mentioned situation, and by aerating the liquid to be measured containing Sen C yellow ions by blowing aeration gas into the liquid to be measured under acidic or neutral conditions. A method in which sulfur ions are converted into hydrogen sulfide and aeration is transferred into the gas, and then the concentration of hydrogen sulfide in the obtained hydrogen sulfide-containing gas is directly measured in the gas phase using a hydrogen sulfide detector using a diaphragm type hydrogen sulfide electrode, etc. A method for measuring sulfur ion concentration that reliably prevents contamination of the detector due to contact between the liquid to be measured and the hydrogen sulfide detector, and measures sulfur ion concentration with high precision and high sensitivity over a long period of time. The purpose is to provide the following.

Hereinafter, one embodiment of the present invention will be described using FIGS. 1 to 3.

Figure 1 shows an example of a sulfur ion concentration measuring device used in carrying out the present invention. In this device, the components to be measured are sulfur ions (S), water sulfide (5), element (H□S), etc. A liquid to be measured 1, such as domestic wastewater, industrial wastewater, river water, etc., containing . Reference numeral 4 denotes an acid tank, and the acid aqueous solution contained therein is transferred to the acid supply pump 5 between the pump 2 and the mixer 30.
In the meantime, it is mixed into the i1+lI constant solution. The mixture of the liquid to be measured and the acid aqueous solution is uniformly mixed when passing through the mixer 3, and its pi-1 is set to 8 or less, particularly preferably from 7 to 4. The sulfur ions inside turn into hydrogen sulfide.

As the acid aqueous solution, a 0.5 to 2 molar aqueous solution of hydrochloric acid, sulfuric acid, etc. is preferable.

The liquid to be measured that has passed through the mixer 3 is then sent to the nozzle section 6, where aeration gas is blown into the liquid to transfer hydrogen sulfide in the liquid to be measured into the aeration gas.

The main body 7 of the gage section 6 is formed into a cylindrical shape with a bottom, and an inflow section 8 for the pH-adjusted liquid to be measured is formed on the lower side wall thereof, and an inflow section 8 for the pH-adjusted liquid to be measured is formed on the side wall of the intermediate portion. Flow (6) This is due to the presence of a mountain portion 9. The mixer 3 completely passes through, I
The liquid to be measured, which has been adjusted to -1 to 8 or less, enters the inflow part 8 and the sage tube main body 7, rises inside the main body 7, reaches the outflow part 9, and is discharged from there to the outside, thereby reducing the layer surface. is designed so that it does not exceed 9 at the outflow portion. In addition,? Ir
The measuring liquid from the outlet 9 is sent to a wastewater treatment tank (not shown) or the like.

AIl *i: An air supply pump: 7" 11 is attached to the side wall of the main body 7" of the barge pipe from the arm IOK.

The air discharge part of this pump 7'll is inserted airtightly through the side wall of the main body 7, and the rear end of the air supply/mother inlet 12 is inserted into the air discharge part of the main body 7 by immersing its tip side in the liquid to be measured. When this bong is operated, air is continuously sent into the liquid to be measured, aerating the liquid to be measured, and hydrogen sulfide in the liquid to be measured is transferred to the aeration gas. Quantitatively transfer to the inside. That is, FIG. 2 shows this state, and in this graph, pi (of the liquid to be measured is 8 or less, %, ρ
Hydrogen sulfide in the liquid to be measured quantitatively migrates into the gas phase under dynamic conditions, and as Pl] exceeds 8, the amount of hydrogen sulfide transferred into the gas phase decreases rapidly. Indicate that.

Next, the gas containing hydrogen sulfide rises inside the main body 7 and comes into contact with the hydrogen sulfide detector 13 such as a diaphragm-type hydrogen sulfide electrode 13' inserted into the main body 7 due to the upper part of the living body 7. do,
The hydrogen sulfide concentration in the aeration gas is directly measured in the gas phase, and an electrical signal proportional to the hydrogen sulfide concentration is sent to the electrical section 14.
The hydrogen sulfide concentration recorded by the recording needle 15 is proportional to the sulfur ion concentration in the liquid to be measured.

As shown in FIG. 3, the diaphragm type hydrogen sulfide electrode 13' has a hydrogen sulfide permeable membrane 16 made of Teflon or the like filled with an internal liquid 17, and a silver sulfide electrode 18 and a silver-silver chloride electrode 19 arranged therein. A known diaphragm-type hydrogen sulfide electrode can be suitably used, but
A diaphragm-type sulfide containing hygroscopic glycerin, ethylene glycol, etc. in the internal liquid between the diaphragm and the electrode, especially a hygroscopic agent such as glycerin or ethylene glycol in the upper internal liquid, and a surfactant to reduce viscosity. Hydrogen electrodes are preferred.

In addition, 20 is an exhaust hole bored in the side wall of the main body 7 above the imaged hydrogen concentration detection part 13m of the electrode 13'.
After the hydrogen sulfide concentration of the aeration gas is measured, it is discharged from the system through this exhaust hole.

In this example, an acid is added to the liquid to be measured to adjust p)I, and this is aerated to convert sulfur ions in the liquid to be measured into hydrogen sulfide. to migrate;
Since the hydrogen sulfide detector measures the hydrogen sulfide concentration in the aeration gas, the detector is not in direct contact with the liquid to be measured. Therefore, since the detector 13 is not contaminated by the liquid to be measured, it is possible to use a p-filtration device using a one-paper filter, an electrode cleaning device using mechanical polishing, or an electrode cleaning device using mechanical polishing, which is indispensable in the conventional method. This eliminates the need for a calibration device using a standard solution and a control unit for controlling these, which simplifies the device, makes it easier to manufacture, and significantly reduces manufacturing costs. In addition, when using a diaphragm type hydrogen sulfide electrode, since it is a composite electrode and does not require a electrode, there is no need to consider soiling or maintenance of the reference electrode, and the electrode is not contaminated, so it can be used for a long time. Continuous operation without maintenance for a period of time becomes effective (9). In addition, when a diaphragm-type hydrogen sulfide electrode containing glycerin and an activator is used in the internal liquid, it is particularly preferable to obtain a stable measurement source. By transferring the hydrogen sulfide in the injected liquid to be measured into the aeration gas, hydrogen sulfide can be concentrated as shown in the actual measurement example in the table below, which is approximately 30 times more concentrated than the conventional method. It becomes highly sensitive.

Actual measurement example of the concentration state of hydrogen sulfide by aeration By measuring hydrogen sulfide a degree in the gas phase, the surface line area of 1'+t mA becomes wider (quantification range of this example f1.01 to 30000 mg/ l, conventional method 3~
3000mg/l).

Furthermore, in this embodiment, since the air supply pump 11 is fixed to the main body 7 by the arm 10, the vibration of the pump 11 is properly transmitted to the internal liquid near the sensing element of the diaphragm-type hydrogen sulfide electrode. This is effective in constantly updating the electrode tail; it is useful for improving the speed of response and the actual situation.

Figure 4 shows an example of a song for the sulfur ion concentration measuring device used in the practice of the present invention.
) 9 [This is a detector type that measures the sulfur ion concentration by immersing it in the desired liquid to be measured. This device is A'-)
The lower end of the tube body 7 is open, and from there the liquid to be measured enters the main body 7 at a rate of 7 At, and the acid supplied by the acid supply pump 5, which is taken into the main body 7 by the arm 10, causes
, +-i below 8 tC adjusted 91, then l aeration tL
Since the structure of the song is the same as that of the previous embodiment, the same reference numerals will be given to the same parts and the explanation thereof will be omitted.

- Since the volume #t in the main body 7 of the f-tube is relatively small, the number #t of the liquid to be measured can be reduced to 8 or less by the above-mentioned simple method, and this device is easy to use.

If the (J() of the liquid to be measured is 8 or less and there is no need to adjust the pi(), use the acid supply bottle f5 and the acid tank 4.
There is no need to equip it, resulting in an even simpler structure.

Although air is used as the aeration gas in the above embodiments, the aeration gas is not limited to this, and nitrogen or the like may be supplied from an rW tank. The electrode 12 was placed on top of this, but the electrode part was separated from the aeration part, and the aeration gas containing hydrogen sulfide obtained in the aeration part was sent to the electrode part through a piezo etc., and the electrode part was separated from the aeration part. The hydrogen sulfide concentration may be measured at different locations, and other modifications may be made without departing from the gist of the present invention.

Therefore, in the present invention, the liquid to be measured is made neutral or acidic so that the sulfur ions are changed to hydrogen sulfide, and the liquid to be measured is aerated with an aeration gas.
The sulfur ion concentration in the liquid to be measured is indirectly measured by transferring the hydrogen sulfide into the aeration gas and then measuring the concentration of hydrogen sulfide in the aeration gas containing the obtained sulfur 1 arsenic. However, in this case, the detector and the liquid to be measured are not in direct contact (-), so the detector will not be contaminated and will operate stably for a long period of time without any change in sensitivity. It can be applied to liquids to be measured that cannot be measured using conventional methods, such as wastewater containing activators, without any pretreatment.Furthermore, since there is no direct contact between the liquid to be measured and the detector, The device is simplified and the manufacturing cost is greatly reduced because the overpass device using a P paper filter, the electrode cleaning device blind, the calibration device, and the control device that controls these are unnecessary. The method also has some disadvantages such as a wider area of surface lines compared to the conventional method.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a sulfur ion concentration measuring device used in the practice of the present invention, and FIG. 2 is a (13) relationship between the polar potentials of -1 and 1 of the liquid to be measured defined using the same device. 3 is an enlarged partial cross-sectional side view of a diaphragm-type hydrogen sulfide electrode used in the device, and FIG. 4 is a block diagram showing another example of the sulfur ion concentration measuring device used in the implementation of the present invention. be. 1... Subject i11?1J constant solution, 4... Acid tank, 7.
・・Parts main body, 11 ・Air pump, 12 ・・
Air blowing! Izo, 13...Hydrogen sulfide detector・Applicant: Denki Kagaku Keiki Co., Ltd. Agent, Patent attorney: Hajime Takahata, Seishoji, Takashi Kojima (14)

Claims (1)

[Claims] 1. By aerating the liquid to be measured containing sulfur ions by blowing aeration gas under acidic or neutral conditions, the sulfur ions in the liquid to be measured are transferred into the aeration gas as hydrogen sulfide. The sulfur ion method is characterized in that the sulfur ion concentration in the liquid to be measured is indirectly measured by measuring the concentration of hydrogen sulfide in the obtained hydrogen sulfide-containing aeration gas with a hydrogen sulfide detector. Concentration measurement method. 2. The measuring method according to claim 1, wherein the aeration gas is air. 3. The measuring method according to claim 1 or 2, wherein the hydrogen sulfide detector is a diaphragm-type hydrogen sulfide electrode.