Search result: HJ 548-2016 (HJ 548-2009 Older version)
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| HJ 548-2016 | English | 229 |
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Stationary source emissions. Determination of hydrogen chloride. Silver nitrate titration
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HJ 548-2016
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| HJ 548-2009 | English | 319 |
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Stationary source emissions. Determination of hydrogen chloride. Silver nitrate titration method
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HJ 548-2009
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| Standard ID | HJ 548-2016 (HJ548-2016) | | Description (Translated English) | Stationary source emissions. Determination of hydrogen chloride. Silver nitrate titration | | Sector / Industry | Environmental Protection Industry Standard | | Classification of Chinese Standard | Z25 | | Classification of International Standard | 13.040.40 | | Word Count Estimation | 10,160 | | Date of Issue | 2016-05-13 | | Date of Implementation | 2016-08-01 | | Older Standard (superseded by this standard) | HJ 548-2009 | | Quoted Standard | GB/T 16157; HJ/T 373 | | Regulation (derived from) | Ministry of Environmental Protection Announcement No. 39 of 2016 | | Summary | This standard specifies the silver nitrate volumetric method for the determination of hydrogen chloride in fixed sources of exhaust gas. This standard applies to the determination of hydrogen chloride in fixed source exhaust gas. When the sample volume is 15L (standard state), the method detection limit is 2 mg/m^3 and the lower limit of determination is 8.0 mg/m^3. |
HJ 548-2016
Stationary source emissions-Determination of hydrogen chloride-Silver nitrate titration
National Environmental Protection Standard of the People 's Republic of China
Replacing HJ 548-2009
Determination of hydrogen chloride in fixed source waste gas
Silver nitrate volumetric method
Stationary source emissions-Determination of hydrogen chloride
Silver nitrate titration
2016-05-13 release
2016-08-01 implementation
Ministry of Environmental Protection released
Directory
Preface .ii
1 Scope of application
2 normative reference documents
3 Principle of the method
Interference and elimination
5 reagents and materials 1
6 instruments and equipment 3
7 Sample 3
8 Analysis steps
The results are calculated and expressed
10 precision and accuracy
Quality assurance and quality control
12 Waste treatment
13 Precautions
Preface
In order to implement the Environmental Protection Law of the People's Republic of China and the Law of the People's Republic of China on the Prevention and Control of Atmospheric Pollution,
Protection of human health, regulate the fixed source of waste gas in the determination of hydrogen chloride, the development of this standard.
This standard specifies the silver nitrate volumetric method for the determination of hydrogen chloride in the waste of fixed sources.
This standard is the "fixed source of waste gas hydrogen chloride determination of silver nitrate capacity (temporary)" (HJ 548-2009) of the
Revised.
This standard was first published in.2009, the original standard drafting unit for the Beijing Environmental Protection Monitoring Center. This time for the first time
The main contents of the amendments and amendments are as follows.
- revised method of reagents and materials, instruments and equipment, sample collection and analysis steps.
- complements the interference and elimination and quality assurance and quality control parts.
- Increased precision, accuracy, result representation and waste disposal terms.
Since the implementation of the standard date, the original standard "fixed sources of waste gas hydrogen chloride determination of silver nitrate capacity (temporary)"
(HJ 548-2009).
This standard is organized by the Ministry of Environmental Protection Science and Technology Standards Division.
The drafting of this standard. Beijing Environmental Protection Monitoring Center.
The standard verification unit. Beijing Physical and Chemical Analysis and Testing Center, Peking University Environmental Engineering Laboratory, Beijing Fangshan District
Environmental Protection Monitoring Station, Beijing Haidian District Environmental Protection Bureau Monitoring Station, Jiangsu Province Environmental Monitoring Center, Beijing Environmental Protection
Monitoring center.
The environmental protection department of this standard approved on May 13,.2016.
This standard has been implemented since August 1,.2016.
This standard is explained by the Ministry of Environmental Protection.
Determination of hydrogen chloride in fixed sources - Silver nitrate volumetric method
WARNING. Hydrogen chloride is harmful to the human body. When sampling, wear protective equipment in a sampling environment to avoid inhalation or contact with skin
And eyes. Nitric acid used in the experiment has strong oxidizing and corrosive, the operation should wear protective equipment, solution preparation and sample
The pretreatment process should be carried out in a fume hood.
1 Scope of application
This standard specifies the silver nitrate volumetric method for the determination of hydrogen chloride in the waste of fixed sources.
This standard is applicable to the determination of hydrogen chloride in waste gas from fixed sources.
When the sampling volume is 15 L (standard state), the detection limit is 2 mg/m3 and the determination limit is 8.0 mg/m3.
2 normative reference documents
The contents of this standard refer to the following documents or their terms. Those who do not specify the date of the reference file, the effective version of the appropriate
For this standard.
Determination of particulate matter and sampling method of gaseous pollutants in exhaust gas of fixed pollution sources GB/T 16157
HJ/T 373 fixed pollution source monitoring quality assurance and quality control technical specifications (Trial)
3 Principle of the method
Hydrogen chloride is absorbed by sodium hydroxide solution, under neutral conditions, with potassium chromate as indicator, with silver nitrate standard solution
Titration, the formation of silver chloride precipitation, excessive silver ions and potassium chromate indicator reaction to produce shallow brick red silver chromate precipitation, indicating
Titration end point, the reaction is as follows.
4 interference and elimination
When the exhaust gas contains sulfide, sulfur dioxide, the method has a positive interference. Hydrogen sulfide concentration ≤ 1000 mg/m3,
The concentration of sulfur dioxide ≤ 10000 mg/m3, can be added by adding 1 ml of 30% hydrogen peroxide to eliminate interference.
Granular chloride has a positive effect on the process; when the sulfuric acid mist concentration in the exhaust gas is > 15 g/m3,
The process of white precipitation, the impact of the end of the titration process to determine; when the test liquid iron content > 10 mg/L, the method
The end point of the titration process has an effect. The above interference can be removed by filtration through sampling at the time of sampling.
Exhaust gas in the coexistence of chlorine (Cl2), with sodium hydroxide reaction to produce the same amount of chloride ions and hypochlorite ions, interference
Determination of hydrogen chloride. Determination of hypochlorite by iodometric method, from the total chloride minus its content, that is, to obtain hydrogen chloride content.
5 reagents and materials
Unless otherwise stated, analytical reagents conforming to national standards are used for analysis. Experimental water is a newly prepared deionized
Water or water of the same purity.
↓ →
↓ →
CrOAgCrO2Ag
AgClNOAgNOCl
(Shallow brick red)
5.1 nitric acid. ρ (HNO3) = 1.42 g/ml.
5.2 anhydrous ethanol. ρ (CH3CH2OH) = 0.79 g/ml.
5.3 Sodium chloride (NaCl). excellent grade pure.
Before use should be placed in the porcelain crucible, at 400 ℃ ~ 500 ℃ burning 40 min ~ 50 min, and no longer burst sound. Set
Cooled in the dryer.
5.4 Sodium hydroxide (NaOH).
5.5 Silver nitrate (AgNO3).
Before use should be baked at 105 ℃ for 30 min, placed in the dryer cooling standby.
5.6 Potassium chromate (K2CrO4).
5.7 phenolphthalein (C20H14O4).
5.8 nitric acid solution. c (HNO3) ≈ 0.1 mol/L.
Remove 6.2 ml of nitric acid (5.1) and dilute to 1000 ml with water.
5.9 Ethanol solution. 1 1.
Take 250 ml of absolute ethanol (5.2) and dilute to 500 ml with water.
5.10 sodium hydroxide absorption solution. c (NaOH) = 0.10 mol/L.
Weigh 4.0 g of sodium hydroxide (5.4), with a small amount of water dissolved after the full amount into the 1000 ml volumetric flask, diluted with water and volume
To the mark line, shake, with the current allocation.
5.11 sodium chloride standard solution. c (NaCl) ≈ 0.0141 mol/L.
8.24 g of sodium chloride (5.3) (accurate to 0.0001 g) was weighed by reduction, washed with a small amount of water and transferred to 1000 ml
Capacity bottle, diluted with water and volume to the mark, shake. Stored in a polyethylene bottle, refrigerated below 4 ℃, sealed to save 6
Month.
Accurately remove 10.00 ml The above standard solution in 100 ml volumetric flask, diluted with water volume to the mark, shake,
Now with Calculate the concentration of sodium chloride standard solution according to formula (1) accurately.
()
00.1044.58
NaClc × =
(1)
Where. () NaClc - sodium chloride standard solution concentration, mol/L;
W - the amount of sodium chloride, g;
58.44 - molar mass of sodium chloride, g/mol.
5.12 Silver nitrate standard solution. c (AgNO3) ≈ 0.0141 mol/L.
5.12.1 preparation
Weigh 2.4 g of silver nitrate (5.5), dissolve in water, dilute to 1000 ml, and store in a brown oily reagent bottle at 4 ° C
Under the cold storage, before use calibration.
5.12.2 Calibration
Remove the sodium chloride standard solution (5.11) 25.00 ml in 250 ml Erlenmeyer flask, add 25 ml of water and shake. Add 1 ml
Potassium chromate indicator (5.13), while constantly shaking the conical flask, titrated with silver nitrate standard solution (5.12) to produce
The disappearance of the pale brick red precipitation so far. Record the titration volume of silver nitrate standard solution.
Another 50 ml of water, with the above method for blank titration. Calculate the concentration of silver nitrate standard solution according to formula (2) accurately.
()
00.25AgNOc
VV
× = (2)
Where. () 3AgNOc - silver nitrate standard solution concentration, mol/L;
1c - sodium chloride standard solution concentration, mol/L;
V - titration of sodium chloride solution consumed by silver nitrate standard solution volume, ml;
0V - volume of silver nitrate standard solution consumed by titration blank solution, ml.
5.13 Potassium chromate indicator
Weigh 5.0 g of potassium chromate (5.6) in a small amount of water and add the silver nitrate standard solution (5.12) dropwise to produce
Lost pale brick red precipitation so far. Placed overnight, filtered, discarded precipitation, the filtrate diluted with water volume to 100 ml, stored in the
Brown reagent bottle, frozen at 4 ℃ can be stored for 6 months.
5.14 phenolphthalein indicator
Weigh 0.50 g phenolphthalein (5.7) and dissolve in 100 ml of ethanol solution (5.9). Store in a reagent bottle and cool at 4 ° C or lower
Possession can be saved for 3 months.
6 instruments and equipment
Unless otherwise specified, the use of national standards in accordance with the national standard A glassware.
6.1 Flue gas sampler. flow range 0 L/min ~ 1 L/min, the error is less than 5%.
6.2 Smoke sampler. 5 L/min ~ 50 L/min, smoke gun with heating and insulation function.
6.3 porous glass absorption bottle or large bubble absorption bottle. 75 ml, the absorption bottle should be tightly leak-free, porous glass plate absorption bottle foam
To be uniform, when the flow rate of 0.5 L/min, the resistance should be 5 KPa ± 0.7 KPa.
6.4 brown acid burette. 25.00 ml; or use a digital titrator.
6.5 Acetate microporous membrane. 0.3 μm pore size.
6.6 sampling tube. hard glass or fluorine resin material, can be heated to 120 ℃ above the insulation jacket.
6.7 filter folder. Teflon, size and acetate fiber microporous membrane (6.5) match.
6.8 Connecting tube. Silicone rubber tube with polytetrafluoroethylene hose or PTFE tape.
6.9 Erlenmeyer flask. 250 ml.
6.10 Cooling device. ice bath.
6.11 General laboratory equipment and equipment.
7 samples
7.1 Collection of samples
The sampling and sampling of the sampling point of fixed pollution source should meet the relevant provisions in GB/T 16157. Sampling device shown in Figure 1.
At the time of sampling, two inhaled 50 ml sodium hydroxide absorbing solution (5.10) of the absorption bottle (6.3), in accordance with the collection of gaseous pollutants
Method, at a flow rate of 0.5 L/min to 1.0 L/min, sampled continuously for 1 hour, or collected at equal intervals in 1 hour 3
~ 4 samples. In the sampling process, should keep the sampling insulation jacket temperature of 120 ℃, in order to avoid water vapor in the sampling pipeline
In the condensation. After sampling, the absorbent bottle (6.3) is sealed with a connecting tube (6.8), to be tested.
Figure 1 Schematic diagram of a sampling device for a source of waste gas
Note 1. If the exhaust gas contains particulate chloride, should be between the sampling gun and the absorption bottle containing the acetate fiber microporous membrane (6.5) filter
Folder (6.7).
Note 2. The connection pipe between the sampling gun and the absorption bottle should be as short as possible and check the air tightness and reliability of the system.
Note 3. When the humidity in the exhaust gas is large, the hydrogen chloride is absorbed and mainly exists in the granular state, the sampling point of the layout and sampling should be in accordance with GB/T 16157
In the relevant provisions on the collection of particulate matter. Sampling device shown in Figure 2. After the smoke sampler connected to the heating device (including the diversion valve and containing B
Acid fiber microporous membrane filter folder), after the series of two 50ml sodium hydroxide absorption solution (5.10) absorption bottle (6.3). Through the diverter valve,
The hydrogen chloride gas sampling flow control in the 0.5 L/min ~ 1.0 L/min, for 1 hour sampling, or within 1 hour at equal intervals to collect three ~
4 samples. During the sampling process, keep the soot sampler and the heating device at a temperature of 120 ° C to avoid condensation of water vapor in the sampling line. Mining
After the sample is finished, the absorbent bottle (6.3) is sealed with a connecting tube (6.8)
Figure 2 Schematic diagram of sampling device for particulate matter from pollution sources
7.2 Full program blank
Will be the same batch of two 50ml sodium hydroxide absorption solution (5.10) absorption bottle (6.3) to the sampling site, not with the mining
Sample connection, after sampling to bring back to the laboratory to be tested.
7.3 Sample shipping and storage
Collected samples and the whole program blank, should be measured as soon as possible, if not timely determination, should be below 4 ℃ cold storage, sealed
Save, within 48 h to complete the analysis.
8 Analysis steps
8.1 Analysis of samples
After sampling, the sample solution in the two absorbent bottles was transferred to two conical vials respectively, and the inner wall of the absorbent bottle was washed with a small amount of water,
The lotion is incorporated into the corresponding conical flask. Add 1 drop of phenolphthalein indicator (5.14), drop nitric acid solution (5.8) to red disappears;
Add 1.0 ml of potassium chromate indicator (5.13), while constantly shaking the conical flask, with silver nitrate standard solution (5.12) drops
Set to produce a pale red precipitate that does not disappear. The silver nitrate standard dissolved in the samples from the two conical vials was recorded separately
Liquid volume.
8.2 blank experiment
8.2.1 Lab blank
Take the same batch, the same volume of absorption solution, according to the same sample analysis (8.1) the same steps for laboratory blank titration.
8.2.2 Full program blank
The whole program blank sample (7.2) was subjected to full procedure blank titration according to the same procedure as the analysis (8.1) of the sample.
9 Results calculation and representation
9.1 Results calculation
According to formula (3) to calculate the fixed source of waste gas in the concentration of hydrogen chloride concentration.
Nd
2021 100046.36) 2 () HCl (
CVVV ××× - = ρ (3)
Where. () HCl ρ - the concentration of hydrogen chloride in the exhaust gas of the fixed source, mg/m3;
1V, 2V - titration of the volume of silver nitrate standard solution consumed by the sample in two conical bottles, respectively; ml;
0V - titration of two laboratory blank solutions consumed by silver nitrate standard solution volume average, ml;
2c - concentration of silver nitrate standard solution, mol/L;
36.46 - molar mass of hydrogen chloride (HCl), g/mol;
NdV - sampling volume of dry flue gas in standard state (101.325 KPa, 273 K), L.
9.2 The result is shown
When the concentration of hydrogen chloride in the exhaust gas of the fixed source is less than 10 mg/m3, the result is retained to 1 after the decimal point.
When the concentration of hydrogen chloride in the exhaust gas is greater than or equal to 10 mg/m3, the result retains 3 significant digits.
10 precision and accuracy
10.1 Precision
6 laboratories were treated with chloride concentrations of 7.01 ± 0.34 mg/L, 100 ± 3 mg/L and 150 ± 5 mg/L, respectively
The product was tested six times in parallel. The relative standard deviations in the laboratory were 0.8% ~ 3.0%, 0.4% ~ 0.9%, 0.3% ~ 0.8% respectively;
The relative standard deviations were 1.1%, 0.4% and 0.2%, respectively. The repeatability r was 0.1 mg/L, 1.6 mg/L, 1.7
Mg/L; Reproducibility R was 0.5 mg/L, 6.3 mg/L, 9.9 mg/L, respectively.
10.2 Accuracy
6 laboratories were tested for chloride concentrations of 7.01 ± 0.34 mg/L, 100 ± 3 mg/L and 150 ± 5 mg/L, respectively
The quasi - sample was subjected to 6 parallel determinations. The relative errors in the laboratory were -1.3% ~ 1.6%, 0 ~ 1.0%, 0; relative error
The final values were 0.95% ± 1.22%, 0.17% ± 0.82%, respectively.
11 quality assurance and quality control
11.1 The sampler shall be airtight and flow calibrated before use.
11.2 Each batch of samples contains at least two lab blanks and two full program blanks. Laboratory blank and full program blank determination should be
Less than the method detection limit, or to find the cause, re-sampling.
11.3 Quality control and quality assurance of sample collection Refer to HJ/T 373.
12 Waste treatment
The waste generated in the experiment shall be collected and collected in a centralized manner, and shall be handled safely or entrusted with qualified units.
13 Precautions
13.1 When titrated with silver nitrate standard solution, the sample solution should be neutral or slightly alkaline (pH = 6.5 to 10.5). When the sample solution
When the pH value is low, the titration volume will increase and the positive error will be generated. When the pH value of the sample solution is high, Ag will form Ag2O
Precipitation, impact titration end point determination. If NH4 is present in the sample solution, the pH of the sample solution must be controlled to be 6.5 to 7.2
Ag and NH3 are easy to form Ag (NH3) 2 complex.
13.2 titration must be vigorous shaking, to prevent Cl - AgCl adsorption, so that the solution Cl- concentration decreased, leading to the end of the production
Health, causing negative error.
......
HJ 548-2009
Stationary source emissions.Determination of hydrogen chloride.Silver nitrate titration method
National Environmental Protection Standard of the People's Republic
Determination of hydrogen chloride in fixed pollution source
Silver nitrate capacity method (provisional)
Stationary source emissions-Determination of hydrogen chloride
-Silver nitrate titration method
Released.2009-12-30
2010-04-01 Implementation
Ministry of Environmental Protection released
Ministry of Environmental Protection
announcement
No. 74 of.2009
In order to implement the "Environmental Protection Law of the People's Republic of China", protect the environment, and protect human health, we now approve the lead gas of fixed pollution sources.
The four standards, such as the determination of flame atomic absorption spectrophotometry (tentative), are national environmental protection standards and are released.
The standard name and number are as follows.
I. Determination of lead in fixed pollution sources - Flame atomic absorption spectrophotometry (tentative) (HJ 538-2009);
2. Determination of lead in ambient air by graphite furnace atomic absorption spectrophotometry (tentative) (HJ 539-2009);
III. Determination of arsenic in ambient air and exhaust gases - Spectrophotometric method of silver diethyldithiocarbamate (interim) (HJ 540-2009);
4. Determination of gaseous arsenic in the production of yellow phosphorus - Determination of silver diethyldithiocarbamate spectrophotometry (interim) (HJ 541-2009);
V. Determination of mercury in ambient air - Enrichment of sulfhydryl cotton - Cold atomic fluorescence spectrophotometry (interim) (HJ 542-2009);
6. Determination of mercury in fixed pollution sources - Cold atomic absorption spectrophotometry (provisional) (HJ 543-2009);
VII. Determination of Sulfuric Acid Fog of Fixed Pollution Sources by Ion Chromatography (Provisional) (HJ 544-2009);
VIII. Determination of gaseous total phosphorus in fixed pollution sources - Determination of quinolinol ketone capacity (provisional) (HJ 545-2009);
IX. Determination of Phosphorus Pentoxide in Ambient Air Ascorbic Acid Reduction - Molybdenum Blue Spectrophotometry (Provisional) (HJ 546-2009);
X. Determination of chlorine gas from fixed pollution sources, iodometric method (provisional) (HJ 547-2009);
12. Determination of hydrogen chloride in ambient air and exhaust gas Ion chromatography (interim) (HJ 549-2009);
XIII. Determination of total cobalt in water quality 5-chloro-2-(pyridylazo)-1,3-diaminobenzene spectrophotometry (provisional) (HJ 550-2009);
14. Determination of Chlorine Dioxide in Water Quality Iodometric Method (Provisional) (HJ 551-2009).
The above standards have been implemented since April 1,.2010 and published by the China Environmental Science Press. The standard content can be found on the website of the Ministry of Environmental Protection.
Special announcement.
December 30,.2009
Content
Foreword..iv
1 Scope..1
2 Normative references..1
3 method principle..1
4 Interference and elimination.1
5 Reagents and materials.1
6 instruments and equipment.2
7 samples.3
8 Analysis steps..3
9 result calculation..3
10 Quality Assurance and Quality Control.3
11 Notes 3
Foreword
To protect the environment and protect people in order to implement the Environmental Protection Law of the People's Republic of China and the Law of the People's Republic of China on the Prevention and Control of Air Pollution
The body health, standardize the monitoring method of hydrogen chloride in the fixed source of waste gas, and develop this standard.
This standard specifies the silver nitrate volumetric method for the determination of hydrogen chloride in fixed source exhaust gas.
This standard was formulated by the Science and Technology Standards Department of the Ministry of Environmental Protection.
This standard was drafted. Beijing Environmental Protection Monitoring Center.
This standard was approved by the Ministry of Environmental Protection on December 30,.2009.
This standard has been implemented since April 1,.2010.
This standard is explained by the Ministry of Environmental Protection.
Iv
Determination of hydrogen chloride in fixed pollution source
Silver nitrate capacity method (provisional)
1 Scope of application
This standard specifies the silver nitrate volumetric method for the determination of hydrogen chloride in fixed source exhaust gas.
This standard applies to the determination of hydrogen chloride in fixed pollution source exhaust gas.
The method detection limit of this standard is 0.03 mg. When the sampling volume is 15 L, the detection limit is 2 mg/m3.
2 Normative references
The contents of this standard refer to the terms in the following documents. For undated references, the valid version applies to this standard.
GB/T 16157 Determination of particulate matter in fixed pollution source exhaust gas and sampling method of gaseous pollutants
HJ/T 373 Technical Specifications for Quality Assurance and Quality Control of Fixed Pollution Source Monitoring (Trial)
GB/T 6682 Analytical laboratory water specifications and test methods
3 Principle of the method
After the hydrogen chloride is absorbed by the sodium hydroxide solution, it is titrated with a silver nitrate standard solution under neutral conditions using potassium chromate as an indicator.
Silver chloride precipitates, and excess silver ions react with potassium chromate indicator to form a light brick red silver chromate precipitate indicating the end point of the titration. The reaction formula is as follows.
3Cl AgNO
− → 3NO AgCl− ↓
42Ag CrO
− → 2 4Ag CrO ↓
(light brick red)
4 interference and elimination
4.1 Sulfide, cyanide, chlorine and other halides interfere with the determination, resulting in higher results.
4.2 When chlorine (Cl2) coexists in the exhaust gas, it reacts with sodium hydroxide to form equal amounts of chloride ions and hypochlorite ions to interfere with hydrogen chloride.
The determination, the hypochlorite is determined by the iodometric method, and the amount is subtracted from the total chloride to obtain the hydrogen chloride content.
5 reagents and materials
Unless otherwise stated, analytically pure reagents that meet national standards were used for the analysis. Water, GB/T 6682, third grade.
5.1 Nitric acid. ρ (HNO3) = 1.42 g/ml, excellent grade pure.
5.2 Anhydrous ethanol. ρ (CH3CH2OH) = 0.79 g/ml.
5.3 Nitric acid solution. c (HNO3) = 0.10 mol/L.
Dilute 6.25 ml of nitric acid (5.1) to 100 ml with water and mix.
5.4 Ethanol solution. 1 1.
Take 250 ml of absolute ethanol (5.2), dilute to 500 ml with water, and mix.
5.5 Sodium hydroxide absorption solution. c (NaOH) = 0.10 mol/L.
Dissolve 4.0 g of sodium hydroxide in a small amount of water, dilute to 1 000 ml with water, and mix.
5.6 sodium chloride standard solution
Weigh 0.550 0~0.600 0 g of sodium chloride (NaCl, previously burned in porcelain crucible at 400-500 °C until no longer emitted
Burst, slightly cold, transfer to a weighing bottle, weigh to 0.1 mg), dissolve in water, transfer to a 100 ml volumetric flask, dilute to the mark with water, and shake.
Accurately calculate the concentration of sodium chloride standard solution according to formula (1).
10(NaCl)
58.44
Wc ×= (1)
Where. c (NaCl) - concentration of sodium chloride standard solution, mol/L;
W--the amount of sodium chloride, g;
58.44 - molar mass of sodium chloride, g/mol.
5.7 Silver nitrate standard stock solution. c (AgNO3) ≈ 0.10 mol/L.
5.7.1 Preparation
Weigh 17.00 g of silver nitrate, dissolve in water, dilute to 1 000 ml with water, and store in a brown bottle.
5.7.2 Calibration
Pipette 10.00 ml of sodium chloride standard solution (5.6), place in a white porcelain dish, add 25 ml of water. Add potassium chromate indicator (5.9) 1.0 ml,
With the glass rod constantly stirring, titrate with a silver nitrate standard stock solution until a pale brick red color does not disappear. Recording silver nitrate titration
Liquid volume. Another 35 ml of water was taken and blank titration was carried out in the same manner. Calculate the concentration of silver nitrate standard stock solution according to formula (2).
10.00(AgNO ) cc
VV
×= − (2)
Where. c (AgNO3) - silver nitrate standard stock solution concentration, mol/L;
C1--sodium chloride standard solution concentration, mol/L;
V0--the volume of the silver nitrate stock solution consumed by titrating the blank solution, ml;
V--The volume of the silver nitrate stock solution consumed by the titration of the sodium chloride solution, ml.
5.8 Silver nitrate standard use solution
Draw the calibration standard silver nitrate stock solution (5.7) 10.00 ml, place it in a 100 ml volumetric flask, dilute with water to the mark, mix
Evenly, stored in a brown bottle.
5.9 Potassium chromate indicator
Weigh 5.0 g of potassium chromate (K2CrO4) dissolved in a small amount of water, and add the standard solution of silver nitrate (5.8) dropwise to produce a small amount of light brick red.
The color precipitates. After standing overnight, filtering, discarding the precipitate, the filtrate was diluted with water to 100 ml and stored in a brown reagent bottle.
5.10 Phenolphthalein indicator
Weigh 0.50 g of phenolphthalein and dissolve it in 100 ml of ethanol solution (5.4).
6 Instruments and equipment
Unless otherwise stated, the analysis uses a Class A glass gauge that complies with national standards.
6.1 Flue gas sampler. The flow range is 0~1 L/min.
6.2 Brown acid burette. 25 ml.
6.3 Absorber. Perforated glass absorption bottle, 75 ml.
6.4 Acetate fiber microporous membrane. 0.3 μm.
6.5 sampling tube
Made of hard glass or fluororesin, with appropriate size of pipe material, and should be attached with a thermal insulation jacket that can be heated to above 120 °C.
6.6 Filter Membrane. Teflon, the size is matched with the cellulose fiber microporous membrane.
6.7 connecting pipe
Use a Teflon hose or a silicone rubber tube lined with a Teflon film.
6.8 White porcelain. 75 ml.
7 samples
7.1 Sample collection
According to the "Measurement of particulate matter in fixed pollution source exhaust gas and sampling method of gaseous pollutants" (GB/T 16157). When sampling, connect one
A perforated glass plate absorption bottle containing 30 to 50 ml of sodium hydroxide absorbent (5.5) is sampled at a flow rate of 0.5 L/min for 10 to 30 minutes. in
Keep the temperature of the sample insulation jacket at 120 °C during the sampling process to avoid condensation before the water is absorbed in the bottle.
Note. When the concentration of hydrogen chloride is high, two absorption bottles can be sampled in series, and the sample solutions are combined. After constant volume, an appropriate amount of solution is titrated. If the exhaust contains chloride
For particulate matter, the filter holder should be installed before the absorption bottle.
7.2 Preservation of samples
Sample collection should be analyzed as soon as possible. If it cannot be measured on the same day, the sample should be sealed and stored at 0~4 °C for a period of not more than 48 h.
8 Analysis steps
8.1 Analysis of samples
After sampling, transfer the sample solution to a white porcelain dish, add 1 drop of phenolphthalein indicator (5.10), and add 0.10 mol/L nitric acid solution (5.3).
Until the red just disappeared. Add potassium chromate indicator (5.9) 1.0 ml, keep stirring, use 0.01 mol/L silver nitrate standard solution (5.8)
Titrate until a light brick red color is produced.
8.2 Blank test
Take the same volume of absorbent and perform a blank titration according to 8.1.
9 Calculation of results
Calculate the mass concentration of hydrogen chloride in the fixed source exhaust gas according to formula (3).
Nd
( ) 36.46 1000
HCl
VV c
ρ − × × ×=( ) (3)
Where. ρ (HCl)--the mass concentration of hydrogen chloride in the fixed pollution source exhaust gas, mg/m3;
V1--titration sample solution consumption of silver nitrate standard solution volume, ml;
V0--the titration of the silver nitrate consumed by the titration blank solution standard solution volume, ml;
C2--concentration of silver nitrate standard solution, mol/L;
36.46 - molar mass of hydrogen chloride (HCl), g/mol;
Vnd - the sampling volume of dry gas in the standard state (101.325 kPa, 273 K), L.
10 Quality Assurance and Quality Control
10.1 Quality control and quality assurance are carried out in accordance with HJ/T 373.
10.2 The sampler should be airtight and flow calibrated prior to use. Each batch should have at least one full program blank.
10.3 Used absorbent bottle, connecting tube, etc., after pouring the solution, wash it directly with deionized water, do not wash with tap water;
During the process, pay attention to dustproof, do not touch the mouth of the absorption bottle to prevent the chloride from staining.
11 Precautions
The titration solution should be neutral or slightly alkaline (pH = 6.5 ~ 10.5). In an acidic solution, when the conversion affects the endpoint
Formation of Ag2CrO4 precipitate. Ag will form an Ag2O precipitate in an alkaline solution.
4CrO
− 2
2 7Cr O
......
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