1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA
2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any
3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. ISBN 978-0-626-24320-3 SANS 5217:2010Edition 3.3SOUTH AFRICAN NATIONAL STANDARD Water Free and saline ammonia content Published by SABS Standards Divisio
4、n 1 Dr Lategan Road Groenkloof Private Bag X191 Pretoria 0001Tel: +27 12 428 7911 Fax: +27 12 344 1568 www.sabs.co.za SABS SANS 5217:2010 Edition 3.3 Table of changes Change No. Date Scope Amdt 1 2004 Amended to change the designation of SABS standards to SANS standards and to update referenced stan
5、dards. Amdt 2 2007 Amended to update referenced standards, to correct values for ammoniacal nitrogen in the table in 6.1, and to add information to the procedure involving the retention of liquid for the albuminoidammonia content test (6.7). Amdt 3 2010 Amended to update referenced standards. Forewo
6、rd This South African standard was approved by National Committee SABS SC 147A, Water Water sampling and analysis, in accordance with procedures of the SABS Standards Division, in compliance with annex 3 of the WTO/TBT agreement. This document was published in April 2010. This document supersedes SA
7、NS 5217:2007 (edition 3.2). A vertical line in the margin shows where the text has been technically modified by amendment No. 3. SANS 5217:2010 Edition 3.3 1 Water Free and saline ammonia content 1 Scope and field of application This standard specifies a method of measuring the concentration of un-i
8、onized and ionized ammoniacal nitrogen in water and in wastewater. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced docu
9、ment (including any amendments) applies. Information on currently valid national and international standards can be obtained from the SABS Standards Division. Amdt 1 SANS 111/ISO 835, Laboratory glassware Graduated pipettes. Amdt 1; amdt 3 SANS 112/ISO 648, Laboratory glassware Single volume pipette
10、s. Amdt 1 SANS 115/ISO 385, Laboratory glassware Burettes. Amdt 1; amdt 3 SANS 128/ISO 1042, Laboratory glassware One-mark volumetric flasks. Amdt 1 SANS 3696/ISO 3696, Water for analytical laboratory use Specification and test methods. SANS 5218, Water Albuminoid ammonia content. Amdt 2 3 Principle
11、 A test portion of the sample is distilled under mildly alkaline conditions and the distillate collected in a boric acid solution. Under alkaline conditions and the continuous removal of ammonia by distillation, the quantitative conversion of ammonia is achieved. The liberated ammonia is collected w
12、ith the distillate in an excess of boric acid where an equivalent amount of borate is produced. The borate is titrated with a standard acid solution to the equivalence point, which is detected with a mixed indicator. 4 Reagents NOTE Unless otherwise specified, only use water that complies with the r
13、equirements of SANS 3696 and reagents of analytical reagent grade. 4.1 Sulfuric acid, (H2SO4) stock volumetric solution, c(1/2 H2SO4) = 1,0 mol/L SANS 5217:2010 Edition 3.3 2 4.1.1 Preparation Using a safety pipette, slowly add, while stirring, 28,0 mL of concentrated sulfuric acid (d at 25/25 C = 1
14、,84) to approximately 800 mL of water. Allow to cool and dilute to 1 000 mL in a volumetric flask. Standardize this solution as described in 4.1.2. 4.1.2 Standardization Dry 3 g to 4 g of primary standard anhydrous sodium carbonate (Na2CO3) for 2 h at 180 C and cool in a desiccator. Weigh accurately
15、, to the nearest 0,1 mg, 2,20 g 0,01 g of the dried Na2CO3and transfer to a 500 mL conical flask. Add 50 mL of water and swirl to dissolve the Na2CO3. Add 4 drops of methyl red solution (see 4.4.1) and titrate with the H2SO4 solution (see 4.1.1) to the first appearance of a red colour. Carefully boi
16、l the solution until the colour is discharged, and cool. Continue the titration alternating the addition of H2SO4solution and the boiling and cooling, to the first appearance of a faint red colour that is not discharged on further heating. The concentration, expressed in moles per litre, of the sulf
17、uric acid c(1/2 H2SO4) solution is given by the formula mV0,053where m is the mass of Na2CO3, in grams; V is the volume of H2SO4consumed, in millilitres. 4.2 Sulfuric acid, standard volumetric solution, c(1/2 H2SO4) = 0,10 mol/L Pipette 50,0 mL of the sulfuric acid stock solution (see 4.1) into a 50
18、0 mL volumetric flask and dilute to the mark with water. 4.3 Sulfuric acid, standard volumetric solution, c(1/2 H2SO4) = 0,02 mol/L Pipette 20,0 mL of the sulfuric acid stock solution (see 4.1) into a 1 000 mL volumetric flask and dilute to the mark with water. 4.4 Boric acid/indicator solution 4.4.
19、1 Dissolve 0,05 g of methyl red in 100 mL of ethanol (95 % (V/V). 4.4.2 Dissolve 0,15 g of methylene blue in 100 mL of water. SANS 5217:2010 Edition 3.3 3 4.4.3 Dissolve 20 g of boric acid (H3BO3) in warm water. Allow to cool. Add 10 mL of the methyl red solution (see 4.4.1) and 2 mL of the methylen
20、e blue solution (see 4.4.2) and dilute to 1 L. 4.5 Bromothymol blue indicator solution Dissolve 0,10 g of bromothymol blue in 1,6 mL of NaOH solution (see 4.9) and dilute to 100 mL in a volumetric flask. 4.6 Magnesium oxide, carbonate free Heat the magnesium oxide for 1 h at 500 C to remove carbonat
21、es. 4.7 Anti-bump beads 4.8 Sulfuric acid solution (1 % (V/V) Slowly add, while stirring, 10 mL of concentrated H2SO4(d at 25 /25 C = 1,84) to approximately 800 mL of water and dilute to 1 L. 4.9 Sodium hydroxide solution, c(NaOH) 0,1 mol/L Dissolve 4,0 g of NaOH in approximately 800 mL of water and
22、 dilute to 1 L. 5 Apparatus 5.1 Distillation apparatus, consisting of a distillation flask of capacity in the range 800 mL to 1 000 mL, attached to an anti-splash head and vertical condenser so arranged that the outlet can be immersed in the boric acid solution. 5.2 Distillation mantle, capable of s
23、eating the distillation flask. 5.3 Magnetic stirrer and hotplate. 5.4 Glassware. Where applicable, only use burettes, pipettes and volumetric flasks that comply with the requirements for class A items as specified in SANS 111, SANS 112, SANS 115 and SANS 128, as relevant. Amdt 1; amdt 3 SANS 5217:20
24、10 Edition 3.3 4 6 Procedure NOTE Unless otherwise specified, only use water that complies with the requirements of SANS 3696. 6.1 Select a suitable volume of sample, using the following table as a guide: 1 2 Ammoniacal nitrogen Sample size (as N in mg/L) (mL) 0 1 500 2 10 250 11 20 100 21 50 50,0 5
25、1 100 25,0 NOTE The sample shown above is an estimate made on the basis of a titration using the standard volumetric H2SO4solution (see 4.3), c(1/2 H2SO4) = 0,02 mol/L. Amdt 26.2 Transfer the aliquot to a distillation flask and dilute to approximately 500 mL with water. 6.3 Add 5-6 drops of the brom
26、othymol blue indicator solution (see 4.5) and adjust the pH to a value in the range pH 6,0 (indicator yellow) to pH 7,4 (indicator blue), using either the NaOH solution (see 4.9) or the H2SO4solution (see 4.8), as appropriate. 6.4 Add 0,3 g of light magnesium oxide (see 4.6), mix and add some anti-b
27、ump beads. 6.5 Attach the distillation flask to the anti-splash head and connect to the condenser. 6.6 Immerse the top of the condenser outlet in 50 mL of the boric acid/indicator solution (see 4.4) in a receiving flask. 6.7 Distil vigorously until 250 mL to 300 mL of distillate has been collected.
28、Retain the liquid that remains in the flask to test the albuminoid ammonia content (see SANS 5218). Amdt 2 6.8 Titrate the distillate in the boric acid/indicator solution to the purple end-point, using the standard H2SO4volumetric solution (see 4.3). NOTE The standard H2SO4volumetric solution, c(1/2
29、 H2SO4) = 0,10 mol/L (see 4.2), may be used for the titration of distillates from samples having high ammonium contents. 6.9 Always carry a blank through the whole procedure, substituting water for the sample. SANS 5217:2010 Edition 3.3 5 7 Expression of results The free and saline ammonia, expresse
30、d as nitrogen (N) in mg/L, is given by the formula 021000114,01)(VcVV where V0is the volume of the test portion, in millilitres; V1is the volume of sulfuric acid solution used in titration of the sample distillate, in millilitres; V2is the volume of sulfuric acid solution used in titration of the bl
31、ank distillate, in millilitres; c is the exact concentration of the sulfuric acid used in the titration, c(1/2 H2SO4), in moles per litre. SABS This page has been left blank intentionally SABS Standards Division The objective of the SABS Standards Division is to develop, promote and maintain South A
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