JPS5931451A - Measurement of concentration of chlorine ion in water solution - Google Patents

Abstract

PURPOSE:To carry out a rapid and highly accurate measurement of Cl<-> in a very small amt., by obtaining a quantity of Hg(NO3)2 consumed during the color change of an organic-solvent layer from yellow to purple due to Hg(NO3)2, after adding diphenylcarbazone and the org. solvent to a water solution containing Cl<->, and adjusting the pH value by incorporating nitric acid in it. CONSTITUTION:1ml solution in which 0.1g diphenylcarbazone indicater is dissolved in 100ml special-grade alcohol, 100ml sample water containing Cl<-> (if >=0.5mg Cl<-> is contained, it is diluted), 3ml 0.15N HNO3 solution, and 1ml org. solvent such as toluene or the like are mixed, 0.00141N Hg(NO3)2 solution is dropped under stirring, and the quantity of Hg(NO3)2 consumed during the color change of the org. solvent layer from yellow to purple is obtd. (under the stirring, the org. phase can be seen at the V-shaped swirling part). By this method, Cl<-> at the low concentration down to 0.05ppm can be measured with a 10-20 fold higher sensitivity in <=10min, than the conventional method using Hg(NO3)2.

Description

DETAILED DESCRIPTION OF THE INVENTION Kinoi ψj relates to a simple JM elementary ion a IJj 6+11 method that can quickly and accurately measure chloride ions in an aqueous solution.

In newly constructed thermal power plant boilers, plants that use austenitic stainless steel preparations in Cr, superheaters, and reheaters, the presence of chlorine ions can cause stress corrosion cracking in steel materials, so as a preventive measure, the plant ! 1lI
Prior to J, use desalinated water with a chloride ion concentration of less than α1ppIu 1. The superheater is washed with water until the chlorine ion susceptibility in the system Ur is less than α1 ppto.

In this case, it is necessary to manage the measurement of chlorine ion concentration in the washing water, and the measurement method is t:i absorption photometry (JIEI Kn 10 ■ Rizuki 4 water test method). ), in the case of small if ii Ff1. Second Mizusen method (
JIBKOjO construction water test force method) has been adopted.

In the spectrophotometric method, mercury and mercury are added to thiocyanium in the sample water.
When the ferric ammonium acid bath solution was added, the thiocyanate ions and ferric ions released by the chlorine ions produced an orange-colored absorbing ions and determined the AM accumulation ions. This is the way to do it.

On the other hand, the mercuric nitrate method is a method in which nitric acid is added to the sample water to adjust the pH to 1, and the titration is performed using an αo141N mercuric nitrate standard solution. At the end point, an appropriate amount of mercury ion reacts with the diphenylcarbazone indicator and the color changes from green to purple. The chlorine ion d111 determination method of these authors has the following shortcomings.

In the case of the absorption 5Y:5Y:temperature method, the predetermined field for tj1 salt accumulation ions is n, 05 pp+n, and it can be fully applied to the water quality control method described above (also, the 1 analysis method and E7 for water quality control during washing), but the time required for analysis is Because it takes about 40 minutes, the whole process (washing with water) step 2 (11
Harm 1. There are major consequences, such as wasteful consumption of ground water.

There is no problem as mentioned above because the time required for carp analysis is short, about 10 minutes or more, but the constant fit of chlorine ions is 1. pT) m, and the chlorine ion water l in the flushing system (management standard value is 0.1
14] Also, the water level during washing with water (
1 ('tJlj analysis method cannot be applied.

The present invention): i:, J: We provide a chlorine/f-on analysis method that eliminates and eliminates the drawbacks listed above and can quickly measure the chlorine ion concentration under house arrest with simple analytical operations. That is, in the present invention, diphenylcarbazone indicator and organic #I medium are added in advance to an aqueous solution containing chlorine ions, and after adjusting the pH to 2Ω to &5 by adding nitric acid, By titrating with 16 mercury solutions, 1] mercuric nitrate standard solution consumption until the bath medium layer changes from yellow to purple.
The present invention relates to a method for measuring the concentration of MX ions in an aqueous solution, which is characterized by determining the cumulative ion concentration.

The method of the present invention will be explained in detail below.

The method of the present invention applies the principle of the conventional mercuric nitrate method described above. First, a diphenylcarbazone indicator and an organic solvent are added to an aqueous solution containing chloride ions (hereinafter referred to as test water). pH”j)2.0-55 to 1 with nitric acid
Do 4 verses.

The above-mentioned diphenylcarbazone indicator C is a conventional one, such as diphenylcarbazone α12 dissolved in 100-proof special grade ethyl alcohol and stored in a container.

Muff'il: Ethyl ether, carbon tetrachloride, chloroform, petroleum ether, toluene, etc. can be used as the organic solvent. The addition of organic solvent is carried out at the end point detection window 1a:
'(r- This is done to increase.

That is, as described above, by the mercuric nitrate method,
Excess mercury ions react with the diphenylcarbazone 4i droplet at the thread point to produce purple diphenylcarbazone mercury, but if the crab product is completely extracted into the sample water, a sharp A color change appears. ;ff latent solvent, which is added to achieve complete extraction of the product, and the product is completely extracted into the organic bath agent in the pH range of 2.0 to 5. A sharp purple color can be produced at the end point, and the detection sensitivity is higher than that of conventional methods. It is possible to increase the amount by 1Q to 20 times that of the mercuric 111 acid method. In order to obtain this effect, it is desirable that the volume of the organic solvent added be 1/20 to 1/10 times that of the water tester.

Add the above diphenylcarbazone indicator and organic solvent, and adjust the pH to 2.0 to 5 with nitric acid.Additionally, titrate the mercuric nitrate standard solution to the test water, and the test water turns yellow (7:I). The point at which the color changed to purple was taken as the end point, and the cumulative ion concentration was determined from (11) of the mercuric standard solution.

As the above mercuric nitrate standard solution, the end point detection window 11
Since f increases by as much as 10 to 20 times as described above, the standard solution used in the conventional mercuric nitrate method can be diluted about 10 times and diluted with the following solution.

Here, we will explain an example of the mode of preparing the α00j4N mercuric nitrate standard solution.〇 Take Nitrified Nitrified Second Water Kettle α2422, dissolve it in water containing 20− of the total amount of α25 of nitric acid, and dissolve the total amount of mercuric nitrate with water.
The m-determination of this standard solution is carried out as follows.

The chlorine ion standard solution 10-, which will be described later, was added to the positive 1. (Take in a white porcelain dish, dilute to 100*J with water, add diphenylcarbazone indicator 1-1α15N nitric acid solution 5- and the above-mentioned organic solvents 10-15- and mix. Next, add the above mercuric nitrate standard solution. The point at which the organic solvent layer changes color from yellow to purple (near the end point, titrate with mercuric nitrate standard 'A').
M ff1 - Each drop is stirred with a stirrer to ensure the point of discoloration. If you pay close attention, you can easily distinguish 1j from the discoloration. ) All end points. Here, from the wl number (2) of the mercuric nitrate standard solution obtained above, calculate the factor (1e) of the LD0141N mercuric nitrate standard solution using the following formula.

g'=jQ/z The above chloride ion standard solution, e.g. Ct-α05tny/
Me standard oil is prepared by preheating sodium chloride in a standard test chamber for constant rat analysis at 500 to 600°C for about 40 minutes, leaving it to cool in a desiccator, then taking [18242] correctly and dipping it in water.
Transfer the kumquats to 11 volumetric flasks (7, prepare by adding kumquats to 11 with water.

Next, a specific example will be given, and the method of the present invention will be described.
0 cases of how to find J o n, l's white 6 [take it on a plate. here n
Add 5 ml of 15 N WtM (W), 1 mtir of phenylcarbazo, and toluene and mix well. Then, while stirring with a stirrer, prepare a t1M 12.0 tube [7 α00
141N nitric acid No.: Mercury camphor type 1! The end point is the point at which the yellow color of the solvent layer changes to purple. Let the Me number of the mercuric nitrate standard solution required here be A〇Meanwhile, take 100 m/i of water without chlorine in a white A6 dish,
Did you do the same operation as above and get the result here? Let B be the mV number of i+% acid mercuric solution. Q, E test tJ1 with
This is done to measure Ot-kame in the standard solution of mercuric nitrate. From this result, it can be concluded that the accumulated ion a1 degree contained in the above sample water wanders in the following way. Can be done.

000 0 == (A-B) 11' jll! Second water 6
Factors for Ji standard solution The method of the present invention described in detail above has a higher detection sensitivity than that of the conventional Ni standard solution. (2) The mercuric nitrate standard solution is 10 to 20 times more effective than the conventional [10141
Ratio to N [2, t'too+4+) J and 10-fold dilution (7)
4 can be used. (3) The lower limit of salt ion constant loss is α05 Bpm compared to the conventional IPpm, and the moxibustion output sensitivity is 20 times higher than that of the conventional method. (4) Analysis The time required is almost the same as that of the conventional mercuric nitrate method, which is less than 10 minutes. , which can be applied to the '61 specification of JM's cumulative heat exchanger, etc., in water quality management.

Claims (1)

[Claims] Add diphenylcarbazone indicator and an organic solvent to a water bath containing chlorine ions in advance, and add nitric acid to adjust the total pH to 2.
．． After adjusting the concentration to 0 to 55, determine the chlorine concentration from the mercuric nitrate standard solution eraser 1 until the organic solvent layer changes from yellow to purple by titrating with mercuric nitrate bath solution. 'F! A method for measuring the concentration of chloride ions in aqueous 71M with f-characteristics.