Method for detecting ammonia nitrogen of low mercury salt

Abstract

A method for detecting ammonia nitrogen of a low mercury salt belongs to the technical field of chemical engineering. The method comprises the following steps: preparing a mercury bichloride-potassium iodide-potassium hydroxide solution used as a Nessler's reagent, preparing a potassium sodium tartrate solution, preparing an ammonia nitrogen solution in colorimetric tubes to obtain an ammonia nitrogen standard series, and drawing a calibration curve. The method for determining ammonia nitrogen in wastewater, which uses HgCl2 to prepare the Nessler's reagent, has no precipitate generation, realizes the high accuracy and the high precision of a determination result, and can be used for control analysis. Comparison researches confirm that the detection of the ammonia nitrogen through the Nessler's reagent prepared from KI, KOH and HgCl2 and the optimized potassium sodium tartrate solution guarantees the low content mercury and is fast and simple, and the calibration curve made through the method has a high sensitivity.

Description

technical field

[0001] The invention belongs to the technical field of chemical industry, and in particular relates to a method for detecting ammonia nitrogen of low-mercury salts. Background technique

[0002] Ammonia nitrogen is one of the main indicators for evaluating water quality, and the determination of ammonia nitrogen in water and wastewater is a relatively common item in water quality analysis. Determination methods usually include Nessler's reagent colorimetry, phenol hypochlorite colorimetry and electrode method. Nessler's reagent photometry is one of the standard methods commonly used in environmental monitoring to determine ammonia nitrogen in water and wastewater.

[0003] Nessler's reagent has two preparation methods: the first method utilizes KI, HgI 2 and NaOH, the second method utilizes KI, KOH and HgCl 2 preparation. At present, the first method is used to prepare more, and the method is simple to operate, but precipitation occurs, and it can be used...

Examples

Embodiment 1

[0025] Potassium sodium tartrate is prepared according to the national standard: Weigh 50g of potassium sodium tartrate and dissolve it in 100ml of water, heat to boil to remove ammonia, let cool to room temperature, add water to make up to 100ml. The mass concentration of the prepared potassium sodium tartrate is ρ=500g / l.

[0026] Nessler's reagent is prepared by the method required by the national standard: mercuric dichloride-potassium iodide-potassium hydroxide (HgC1 2 -KI-KOH) solution: Weigh 15.0g of potassium hydroxide (KOH), dissolve it in 50ml of water, and cool to room temperature; weigh 5.0g of potassium iodide (KI), dissolve it in 10ml of water, and dissolve 2.50g of dichloro Mercury (HgCl 2 ) powder was added to the potassium iodide solution several times, and 0.8gHgCl was added for the first time 2 The powder dissolution time is 1min, completely dissolved, the second time 0.5gHgCl 2 Powder, the dissolution time is 1.5min, add 0.5gHgCl for the third time 2 Th...

Embodiment 2

[0031] Potassium sodium tartrate is prepared according to the national standard: Weigh 50g of potassium sodium tartrate and dissolve it in 100ml of water, heat to boil to remove ammonia, let cool to room temperature, add water to make up to 100ml. The mass concentration of the prepared potassium sodium tartrate is ρ=500g / l.

[0032] Nessler's reagent preparation, using the rapid method Nessler's reagent preparation: Weigh 16g of sodium hydroxide, dissolve in 50ml of water, fully cool to room temperature. Another weighed 7g potassium iodide and 10g mercuric iodide (HgI 2 ) dissolved in water, then slowly pour this solution into sodium hydroxide solution under stirring, dilute it to 100ml with water, store it in a polyethylene bottle, and keep it sealed.

[0033] In seven 50ml colorimetric tubes, add 0ml, 0.5ml, 1.0ml, 3.0ml, 5.0ml, 7.0ml and 10.0ml of ammonia nitrogen standard working solution respectively, the mass concentration of ammonia nitrogen standard working solution i...

Embodiment 3

[0039] Step 1, preparation of mercuric dichloride-potassium iodide-potassium hydroxide solution is Nessler's reagent

[0040] Weigh 15.0g of potassium hydroxide, dissolve in 50ml of water, cool to room temperature for later use;

[0041] Weigh 5.0g of potassium iodide, dissolve it in 10ml of water, and add 2.50g of mercuric dichloride powder into the potassium iodide solution several times while stirring. Add 0.8g of mercuric dichloride powder for the first time, and the dissolution time is 1min. Add 0.5g, dissolving time is 1.5min, add 0.5g for the third time, dissolving time is 3min, add 0.3g for the fourth time, dissolving time is 5min, add 0.2g for the fifth time, dissolving time is 5min, add for the sixth time 0.1g, the dissolution time is 8min, add 0.05g for the seventh time, the dissolution time is 15min, add 0.05g for the eighth time, the dissolution time is 30min, the mercuric dichloride powder is not completely dissolved, stop adding the mercuric dichloride powder; ...

technical field

[0001] The invention belongs to the technical field of chemical industry, and in particular relates to a method for detecting ammonia nitrogen of low-mercury salts. Background technique

[0002] Ammonia nitrogen is one of the main indicators for evaluating water quality, and the determination of ammonia nitrogen in water and wastewater is a relatively common item in water quality analysis. Determination methods usually include Nessler's reagent colorimetry, phenol hypochlorite colorimetry and electrode method. Nessler's reagent photometry is one of the standard methods commonly used in environmental monitoring to determine ammonia nitrogen in water and wastewater.

[0003] Nessler's reagent has two preparation methods: the first method utilizes KI, HgI 2 and NaOH, the second method utilizes KI, KOH and HgCl 2 preparation. At present, the first method is used to prepare more, and the method is simple to operate, but precipitation occurs, and it can be used...

Examples

Embodiment 1

[0025] Potassium sodium tartrate is prepared according to the national standard: Weigh 50g of potassium sodium tartrate and dissolve it in 100ml of water, heat to boil to remove ammonia, let cool to room temperature, add water to make up to 100ml. The mass concentration of the prepared potassium sodium tartrate is ρ=500g / l.

[0026] Nessler's reagent is prepared by the method required by the national standard: mercuric dichloride-potassium iodide-potassium hydroxide (HgC1 2 -KI-KOH) solution: Weigh 15.0g of potassium hydroxide (KOH), dissolve it in 50ml of water, and cool to room temperature; weigh 5.0g of potassium iodide (KI), dissolve it in 10ml of water, and dissolve 2.50g of dichloro Mercury (HgCl 2 ) powder was added to the potassium iodide solution several times, and 0.8gHgCl was added for the first time 2 The powder dissolution time is 1min, completely dissolved, the second time 0.5gHgCl 2 Powder, the dissolution time is 1.5min, add 0.5gHgCl for the third time 2 Th...

Embodiment 2

[0031] Potassium sodium tartrate is prepared according to the national standard: Weigh 50g of potassium sodium tartrate and dissolve it in 100ml of water, heat to boil to remove ammonia, let cool to room temperature, add water to make up to 100ml. The mass concentration of the prepared potassium sodium tartrate is ρ=500g / l.

[0032] Nessler's reagent preparation, using the rapid method Nessler's reagent preparation: Weigh 16g of sodium hydroxide, dissolve in 50ml of water, fully cool to room temperature. Another weighed 7g potassium iodide and 10g mercuric iodide (HgI 2 ) dissolved in water, then slowly pour this solution into sodium hydroxide solution under stirring, dilute it to 100ml with water, store it in a polyethylene bottle, and keep it sealed.

[0033] In seven 50ml colorimetric tubes, add 0ml, 0.5ml, 1.0ml, 3.0ml, 5.0ml, 7.0ml and 10.0ml of ammonia nitrogen standard working solution respectively, the mass concentration of ammonia nitrogen standard working solution i...

Embodiment 3

[0039] Step 1, preparation of mercuric dichloride-potassium iodide-potassium hydroxide solution is Nessler's reagent

[0040] Weigh 15.0g of potassium hydroxide, dissolve in 50ml of water, cool to room temperature for later use;

[0041] Weigh 5.0g of potassium iodide, dissolve it in 10ml of water, and add 2.50g of mercuric dichloride powder into the potassium iodide solution several times while stirring. Add 0.8g of mercuric dichloride powder for the first time, and the dissolution time is 1min. Add 0.5g, dissolving time is 1.5min, add 0.5g for the third time, dissolving time is 3min, add 0.3g for the fourth time, dissolving time is 5min, add 0.2g for the fifth time, dissolving time is 5min, add for the sixth time 0.1g, the dissolution time is 8min, add 0.05g for the seventh time, the dissolution time is 15min, add 0.05g for the eighth time, the dissolution time is 30min, the mercuric dichloride powder is not completely dissolved, stop adding the mercuric dichloride powder; ...

Images