GB/T 15555.1-1995 Determination of total mercury in solid wastes - Cold atomic absorption spectrophotometry
Some standard content:
National Standard of the People's Republic of China
Determination of total mercury in solid waste
Cold atomic absorption spectrophotometry
Solid waste-Determination of total mercury-Cold atomic absorption spectrometry 1 Subject content and scope of application
GB/T15555.1—1995
1.1 This standard specifies the potassium permanganate-potassium persulfate digestion cold atomic absorption spectrophotometry for the determination of total mercury in solid waste leachate. 1.2 This standard method is applicable to the determination of total mercury in solid waste leachate. 1.2.1 Under the best conditions (high sensitivity of the mercury analyzer, extremely small baseline drift and reagent blank value), when the sample volume is 200mL, the minimum detection concentration can reach 0.05ug/L. Under normal circumstances, the determination range is 0.2～50μg/L. 1.2.2 Interference
When the iodide ion concentration is equal to or greater than 3.8mg/L, it will significantly affect the precision and recovery rate. If the organic content is high and the maximum amount of the prescribed digestion reagent is insufficient to oxidize the organic matter in the sample, the method is not applicable. 2 Principle
In sulfuric acid-nitric acid medium and under heating conditions, various mercury compounds in the test solution are digested with oxidants such as potassium permanganate and potassium persulfate to convert all the mercury contained into divalent inorganic mercury. The excess oxidant is reduced with hydroxylamine hydrochloride, and under acidic conditions, divalent mercury is reduced to metallic mercury with stannous chloride. Air or nitrogen is introduced at room temperature to vaporize the metallic mercury, which is then introduced into a cold atomic absorption mercury analyzer to measure the absorbance at 253.7 nm. 3 Reagents
Unless otherwise specified, reagents that meet national standards or professional standards are used during analysis. 3.1 Mercury-free distilled water: Double redistilled water or electrodialysis deionized water can meet the requirements. Distilled water can also be acidified to pH 3 with high-grade pure hydrochloric acid and then passed through a thiol cotton fiber tube (3.2) to remove mercury. 3.2 Mercapto cotton fiber mercury removal tube: In a glass tube with an inner diameter of 6-8mm, a length of about 100mm, and a thin end, or in the discharge tube of a 500mL separatory funnel, fill 0.1~~0.2g of mercapto cotton fiber (3.3), and flow the reagent to be purified or distilled water through it at a speed of 10mL/min for 1~2 times to remove all mercury.
3.3 Mercapto cotton fiber: In a brown wide-mouth bottle, add 100mL of acetic acid (CH,SHCOOH), 60mL of acetic anhydride, 40mL of 36% acetic acid, and 0.3mL of concentrated HzSO. Mix well, cool to room temperature, add 30g of long-fiber absorbent cotton, soak it completely, cool it with water, and after the reaction heat dissipates, cover it and put it in an oven at 40±2℃ for 2~4 days before taking it out. Filter with a sand core filter funnel, wash with mercury-free double distilled water (3.1) until neutral, spread out and dry at 30-35℃, put in a brown wide-mouth ground bottle, avoid light, and store at low temperature for use. 3.4 Sulfuric acid (HzSO), p=1.84g/mL, high-grade purity. 3.5 Nitric acid (HNO), p=1.42g/mL, high-grade purity. 3.6 Hydrochloric acid (HC1), 0=1.19g/mL, high-grade purity. Approved by the State Environmental Protection Administration on March 28, 1995
State Technical Supervision Bureau
Implementation on January 1, 1996
3.7 Potassium dichromate (K,Cr20,), high-grade purity. GB/T15555.1-1995
3.8 Potassium permanganate (KMnO,) solution, 5%: Dissolve 50g KMnO, (superior purity, if the purity does not reach the superior purity, recrystallization and purification of KMnO,) in water, dilute to 1000mL, and store in a brown bottle. 3.9 Potassium persulfate (K,S20) solution, 5%: Dissolve 5g potassium persulfate in a small amount of water, dilute to 100mL. Prepare and use immediately. 3.10 Hydroxylamine hydrochloride (NH,OH·HCl) solution, 20%: Dissolve 20g hydroxylamine hydrochloride in water and dilute to 100mL. This solution cannot be stored for a long time.
3.11 Stannous chloride (SnC12) solution, 20%: Add 20g SnCl, into 20mL HCl (3.6), heat slightly to dissolve, and dilute to 100mL with water after cooling. Pass nitrogen at a flow rate of 2.5L/min for about 2 minutes to remove mercury, add a few tin particles to seal and store. 3.12 Activated carbon treated with iodine: weigh 1 part by weight of iodine, 2 parts by weight of potassium iodide and 20 parts by weight of water, make a solution in a beaker, add about 10 parts by weight of granular activated carbon (industrial use, $3mm, 3-7mm long), stir vigorously until the solution is decolorized, filter out the activated carbon with a G1 sand core funnel, dry at about 105℃ for 1-2 hours, and set aside. 3.13 Mercury standard fixed solution (called fixed solution) 0.5g/L: Dissolve 0.5g of potassium dichromate (3.7) in 950mL of water, and then add 50mL of HNO3 (3.5).
3.14 Dilution: Dissolve 0.2 g potassium dichromate (3.7) in 900 mL water, add 28 mL HzSO. (3.4), cool and dilute to 1 000 mL.
3.15 Mercury standard stock solution, 100 μg/mL: Weigh 0.1354 g mercuric chloride (HgCl2) placed in a silica gel desiccator overnight, dissolve it in the stationary solution (3.13), transfer it to a 1000 mL volumetric flask, dilute to volume with the stationary solution, and shake well. 3.16 Mercury intermediate standard solution, 10 μg/mL: Take 10.0 mL of the mercury standard stock solution (3.15), dilute to 100 mL with the stationary solution (3.13).
3.17 Mercury standard working solution, 0.10μg/mL: Pipette 10.0mL of mercury standard intermediate solution (3.16), dilute to 1000mL with stationary solution (3.13), and shake well. Store in a cool place at room temperature. Usually can be used for 3 months. 3.18 Color-changing silica gel: For drying.
3.19 Washing solution: Dissolve 10g potassium dichromate in 9L distilled water, add 1000mL HNO3. 4 Instruments
General laboratory instruments and the following special instruments and equipment: 4.1 Mercury analyzer.
4.2 Mercury reducer, with a volume of 25, 50, and 100mL, respectively, with a ground mouth and a lotus-shaped porous blowing head. 4.3 U-shaped tube, 15×110mm, filled with 60-80mm ordinary granular color-changing silica gel (3.18). 4.4 Three-way valve.
4.5 Mercury absorption device: 250ml glass drying tower filled with iodized activated carbon (3.12). The purification system of the instrument can be connected according to the characteristics and specific conditions of different mercury analyzers. Replace the silica gel in the U-shaped tube. 524
5 Steps
GB/T15555.1--1995
Schematic diagram of double-beam cold atomic absorption mercury analyzer 1--mercury lamp power supply, 2-mercury lamp; 3-·working absorption cell; 4-reference absorption cell; 5-working photosensitive device; 6-reference photosensitive device; 7-lens; 8-color filter; 9-circulation pump; 10-reduction bottle; 11-amplifier and digital display 5.1 Sample storage: Use a hard glass container with a smooth surface. An appropriate amount of fixative (3.13) should be added in advance to the device III that receives the leaching solution. The sample should be stored at 40℃ for no more than 28 days. 5.2 Sample preparation: This method recommends using potassium permanganate-potassium persulfate to digest the sample. Transfer 10~50mL of the test solution (depending on the mercury content) into a 125mL conical flask. If the sample volume is less than 50mL, add an appropriate amount of mercury-free distilled water (3.1) to about 50mL. Add 1.5mL of sulfuric acid (3.4), 4mL of potassium permanganate solution (3.8) (if the purple color fades within 5min, add an appropriate amount of potassium permanganate solution to keep the solution purple), and 4mL of potassium persulfate solution (3.9) in sequence. Insert a small funnel, place it in boiling water and keep the test solution in a near-boiling state for 1h (near-boiling insulation method), remove and cool. Alternatively, add a few glass beads or zeolites to the test solution, insert a small funnel, wipe the bottom of the bottle dry, and heat it on a hot plate to boil for 10min (boiling method). Remove and cool. When measuring, add hydroxylamine hydrochloride solution (3.10) dropwise while shaking until the excess potassium permanganate fades and the generated manganese dioxide is completely dissolved. Transfer to a 100mL volumetric flask and make up to volume with diluent (3.14). 5.3 Blank sample: For each batch of samples analyzed, mercury-free distilled water should be used instead of the leachate sample. Prepare two blank samples according to the above sample treatment (5.2).
5.4 Drawing of calibration curve
Take 8 100mL volumetric flasks, accurately pipette 0, 0.50, 1.00, 1.50, 2.00, 2.50, 3.00 and 4.00mL of mercury standard solution (3.17) into the volumetric flasks, add an appropriate amount of fixative to each volumetric flask to make up to 4.0mL, add diluent to the mark, and shake well. Press (5.5) Test sample steps are measured one by one.
Draw a calibration curve with the blank-corrected measurement values as the ordinate and the mercury concentration (ug/L) of the corresponding standard solution as the abscissa. 5.5 Determination: Take out the mercury reducer air blowing head, draw 10.0mL of the sample or blank solution (5.3) treated by (5.2) one by one and inject it into the mercury reducer, add 1mL of stannous chloride (3.11), quickly insert the air blowing head, turn the three-way valve to the "injection" position, let the carrier gas pass into the mercury reducer, and record the maximum reading of the detection head or the peak height on the recorder. After the pointer or recording pen returns to zero, turn the three-way valve to the "zero calibration", take out the air blowing head, discard the waste liquid, rinse the mercury reducer twice with water, and then wash it once with diluent (oxidize the possible residual Sn2+), the instrument reading returns to zero, and then another sample is measured. 525
Results
GB/T 15555.1--1995Www.bzxZ.net
The concentration of (mercury) in the leachate c (μg/L) is calculated as follows: c(μg/L) c >
Wherein: c
Concentration of mercury in the tested material, g/L;
-volume of sample preparation, mL:
V-volume of the sample, mL.
7Precision and accuracy
7.1 Refer to the national standard GB7468 "Determination of total mercury in water by cold atomic absorption spectrophotometry". 7.2 Indoor, the antimony slag leachate with a mercury content of 0.081ug/L and the bismuth slag leachate with a mercury content of 3.0ug/L were measured in parallel 11 times, and the relative standard deviations were 3.9% and 2.4% respectively. The spiked test was conducted on 8 different waste residue leachates such as electroplating sludge, tailings, antimony slag and arsenic calcium slag (the spiked amount was 0.5~0.8 times the sample content), and the recovery rate was between 95% and 103%. 526
GB/T 15555.1--1995
Appendix A
Precautions
(reference)
A1 When the mercury vapor is brought into the absorption cell by the vacuum or blowing method, if the carrier gas flow rate is too large, the mercury vapor concentration in the absorption cell will be diluted; if it is too small, the gasification rate will slow down, which will reduce the sensitivity. Generally, 0.7~1.2L/min is appropriate. The carrier gas flow rate should be constant. A2 Temperature affects the sensitivity of the measurement. When the room temperature is lower than 10℃, it is not conducive to the volatilization of mercury and the sensitivity is low. And pay attention to the consistency of the temperature of the standard solution and the sample solution.
A3 The volume of the reaction bottle and the gas-liquid ratio also affect the determination. The size of the reaction bottle should be determined according to the volume of the sample to be measured. When using the vacuum or air bubbling method to inject samples, the gas-liquid ratio is best at 2:1 to 3:1. Experience has shown that when the gas-liquid ratio is large, the sensitivity tends to increase. A4 Tin particles are added to the stannous chloride solution to prevent it from being oxidized to high-valent tin and becoming ineffective. A5 Chlorine gas will be produced when potassium permanganate is reduced with hydroxylamine hydrochloride. It must be left for several minutes to allow the chlorine gas to escape, so as not to interfere with the determination of mercury. A6 Mercury is easily adsorbed on the wall of the instrument and the air duct. Plastic ducts should be used instead of rubber tubes for connecting ducts, and the used instrument III should be fully washed. In particular, a small amount of Sn(OH): white precipitate is often stained on the inner wall of the reaction bottle and the air bubbling head. It is very easy to adsorb mercury, which will make the measured value lower and lower in continuous determination. After every 5 to 10 samples are measured, they must be rinsed with hot dilute nitric acid. 47 In order to stabilize the working curve, parallel samples can be used for determination when drawing. A8 Mercury in the reagent and volatile impurities that absorb in the ultraviolet region can be removed in advance by passing purified air or nitrogen. A9 Double-beam cold atomic absorption mercury analyzer has high precision and can overcome the influence of voltage fluctuations, unstable light sources, and environmental atmosphere.
Appendix B
Preparation method of leaching solution
(Supplement)
The standard for solid waste leaching test method is being formulated. The leaching solution used in this method and the following methods shall be prepared according to the following method. After the national standard is promulgated, the leaching solution shall be prepared according to the national standard for solid waste leaching test method. B1 Instruments and materials
B1.1 Distilled water or deionized water.
B1.2 Mixing container: 2L high-density polyethylene bottle with a sealing stopper. B1.3 Oscillator: reciprocating horizontal oscillator. B1.4 Filter device: commercially available complete set of glass sand core filter, fiber filter membrane (pore size 0.45um). B2 Leaching steps
B2.1 Weigh 100g of sample (on a dry basis), place it in a mixing container for leaching, and add 1L of water (including the water content of the sample). B2.2 Fix the mixing container for leaching vertically on an oscillator, adjust the oscillation frequency to 110±10 times/min, the amplitude to 40mm, oscillate at room temperature for 8h, and let it stand for 16h.
B2.3 Separate the solid and liquid phases through a filtration device, and immediately determine the pH value of the filtrate. The filtrate should be analyzed as soon as possible, or the leachate should be properly protected and stored according to the requirements of the specified analysis method.
Note: When the dry solid content of the collected solid waste is less than 0.5% (m/m), it can be directly sampled and analyzed without leaching. If the solid waste is multi-phase and the dry solid content is more than 0.5% (m/m), the solid and liquid phases can be separated, the solid phase is air-dried and ground (it should be able to pass through a $5mm sieve), and then leached. If the liquid phase is compatible with the leachate, they can be combined and mixed before analysis. If the liquid phase and leachate are incompatible, they should be analyzed separately after measuring their respective volumes. 527
Additional Notes:
GB/T 15555.1—1995
This standard was proposed by the Department of Science and Technology Standards of the State Environmental Protection Administration. This standard was drafted by the China National Environmental Monitoring Center. The main drafter of this standard was Qi Wenqi.
This standard is entrusted to the China National Environmental Monitoring Center for interpretation. 5282L/min is appropriate. The carrier gas flow rate should be constant. A2 Temperature has an impact on the sensitivity of the determination. When the room temperature is lower than 10℃, it is not conducive to the volatilization of mercury and the sensitivity is low. And pay attention to the consistency of the temperature of the standard solution and the sample solution.
A3 The volume of the reaction bottle and the gas-liquid ratio also have an impact on the determination. The volume of the reaction bottle should be determined according to the volume of the sample to be measured. When the sample is injected by vacuum or air bubbling method, the gas-liquid ratio is best between 2:1 and 3:1. Experience has shown that when the gas-liquid ratio is large, the sensitivity tends to increase. A4 Tin particles are added to the stannous chloride solution to prevent it from being oxidized to high-valent tin and becoming ineffective. A5 Chlorine gas will be produced when potassium permanganate is reduced with hydroxylamine hydrochloride. It must be left for several minutes to allow the chlorine gas to escape to avoid interfering with the determination of mercury. A6 Mercury is easily adsorbed on the instrument wall and the air guide tube. Plastic tubes should be used instead of rubber tubes for connecting the tubes, and the used device III should be fully washed. In particular, the inner wall of the reaction bottle and the air blower are often stained with a small amount of Sn(OH): white precipitate, which is very easy to absorb mercury, and will make the measured value lower and lower in continuous determination. Every 5 to 10 samples must be rinsed with hot dilute nitric acid. 47 In order to stabilize the working curve, parallel samples can be used for determination when drawing. A8 Mercury in the reagent and volatile impurities that absorb in the ultraviolet region can be removed by purified air or nitrogen in advance. A9 The double-beam cold atomic absorption mercury analyzer has high precision and can overcome the influence of voltage fluctuations, unstable light sources, and environmental atmosphere.
Appendix B
Preparation method of leaching solution
(Supplement)
The standard for solid waste leaching test method is being formulated. The leaching solution used in this method and the following methods is first prepared according to the following method. After the national standard is promulgated, the leaching solution shall be prepared according to the national standard for solid waste leaching test method. B1 Instruments and materials
B1.1 Distilled water or deionized water.
B1.2 Mixing container: a high-density polyethylene bottle with a sealed stopper of 2L. B1.3 Oscillator: a reciprocating horizontal oscillator. B1.4 Filtering device: a commercially available set of glass sand core filters, fiber filter membrane (pore size 0.45um). B2 Leaching steps
B2.1 Weigh 100g of sample (on a dry basis), place it in a mixing container for leaching, and add 1L of water (including the water content of the sample). B2.2 Fix the mixing container for leaching vertically on the oscillator, adjust the oscillation frequency to 110±10 times/min, the amplitude to 40mm, oscillate at room temperature for 8h, and let it stand for 16h.
B2.3 Separate the solid and liquid phases through a filtration device, and immediately determine the pH value of the filtrate. The filtrate should be analyzed as soon as possible, or the leaching solution should be properly protected and stored according to the requirements of the specified analysis method.
Note: When the dry solid content of the collected solid waste is less than 0.5% (m/m), it can be directly sampled and analyzed without leaching. If the solid waste is multi-phase and the dry solid content is more than 0.5% (m/m), the solid and liquid phases can be separated, and the solid phase can be air-dried and ground (it should be able to pass through a $5mm sieve) and then leached. If the liquid phase is compatible with the leachate, they can be combined and mixed before analysis. If the liquid phase and the leachate are incompatible, they should be analyzed separately after measuring their respective volumes. 527
Additional notes:
GB/T 15555.1—1995
This standard was proposed by the Science and Technology Standards Department of the State Environmental Protection Administration. This standard was drafted by the China National Environmental Monitoring Center. The main drafter of this standard is Qi Wenqi.
This standard is entrusted to the China National Environmental Monitoring Center for interpretation. 5282L/min is appropriate. The carrier gas flow rate should be constant. A2 Temperature has an impact on the sensitivity of the determination. When the room temperature is lower than 10℃, it is not conducive to the volatilization of mercury and the sensitivity is low. And pay attention to the consistency of the temperature of the standard solution and the sample solution.
A3 The volume of the reaction bottle and the gas-liquid ratio also have an impact on the determination. The volume of the reaction bottle should be determined according to the volume of the sample to be measured. When the sample is injected by vacuum or air bubbling method, the gas-liquid ratio is best between 2:1 and 3:1. Experience has shown that when the gas-liquid ratio is large, the sensitivity tends to increase. A4 Tin particles are added to the stannous chloride solution to prevent it from being oxidized to high-valent tin and becoming ineffective. A5 Chlorine gas will be produced when potassium permanganate is reduced with hydroxylamine hydrochloride. It must be left for several minutes to allow the chlorine gas to escape to avoid interfering with the determination of mercury. A6 Mercury is easily adsorbed on the instrument wall and the air guide tube. Plastic tubes should be used instead of rubber tubes for connecting the tubes, and the used device III should be fully washed. In particular, the inner wall of the reaction bottle and the air blower are often stained with a small amount of Sn(OH): white precipitate, which is very easy to absorb mercury, and will make the measured value lower and lower in continuous determination. Every 5 to 10 samples must be rinsed with hot dilute nitric acid. 47 In order to stabilize the working curve, parallel samples can be used for determination when drawing. A8 Mercury in the reagent and volatile impurities that absorb in the ultraviolet region can be removed by purified air or nitrogen in advance. A9 The double-beam cold atomic absorption mercury analyzer has high precision and can overcome the influence of voltage fluctuations, unstable light sources, and environmental atmosphere.
Appendix B
Preparation method of leaching solution
(Supplement)
The standard for solid waste leaching test method is being formulated. The leaching solution used in this method and the following methods is first prepared according to the following method. After the national standard is promulgated, the leaching solution shall be prepared according to the national standard for solid waste leaching test method. B1 Instruments and materials
B1.1 Distilled water or deionized water.
B1.2 Mixing container: a high-density polyethylene bottle with a sealed stopper of 2L. B1.3 Oscillator: a reciprocating horizontal oscillator. B1.4 Filtering device: a commercially available set of glass sand core filters, fiber filter membrane (pore size 0.45um). B2 Leaching steps
B2.1 Weigh 100g of sample (on a dry basis), place it in a mixing container for leaching, and add 1L of water (including the water content of the sample). B2.2 Fix the mixing container for leaching vertically on the oscillator, adjust the oscillation frequency to 110±10 times/min, the amplitude to 40mm, oscillate at room temperature for 8h, and let it stand for 16h.
B2.3 Separate the solid and liquid phases through a filtration device, and immediately determine the pH value of the filtrate. The filtrate should be analyzed as soon as possible, or the leaching solution should be properly protected and stored according to the requirements of the specified analysis method.
Note: When the dry solid content of the collected solid waste is less than 0.5% (m/m), it can be directly sampled and analyzed without leaching. If the solid waste is multi-phase and the dry solid content is more than 0.5% (m/m), the solid and liquid phases can be separated, and the solid phase can be air-dried and ground (it should be able to pass through a $5mm sieve) and then leached. If the liquid phase is compatible with the leachate, they can be combined and mixed before analysis. If the liquid phase and the leachate are incompatible, they should be analyzed separately after measuring their respective volumes. 527
Additional notes:
GB/T 15555.1—1995
This standard was proposed by the Science and Technology Standards Department of the State Environmental Protection Administration. This standard was drafted by the China National Environmental Monitoring Center. The main drafter of this standard is Qi Wenqi.
This standard is entrusted to the China National Environmental Monitoring Center for interpretation. 528
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