1、UDC 628.1/.3 : 620.1 : 543.3 : 546.226-128.2 : 543.244 DEUTSCHE NORM January 1985 - DIN 38 405 German standard methods for the examination of water, waste water and sludge - Anions (group D) Part 5 Determination of sulfate ions (D 5) Deutsche Einheitsverfahren zur Wasser-, Abwasser- und Schlammunter
2、suchung; Anionen (Gruppe D); Bestimmung der Sulfat-Ionen (D 5) in keeping with current practice in standards published by the international Organization for Standardization flso), a comma has been used throughout as the decimal marker. This standard has been prepared jointly by Study Group Wasserche
3、mie (Water chemistry) of the Gesellschaft Deutscher Chemiker (German Chemists Society) (see Explanatory notes). It will be necessary to resort to the services of specialists and to make use of specialized laboratories in connection with the examinations specified in this standard. 1 Determination of
4、 sulfate ions by complexometric titration after cation exchange 1 .I Field of application The method is applicable to drinking water, process water and surface water with sulfate ion concentrations of 20 to 300 mg/l. Water samples of lower sulfate ion concentration shall be concentrated by evaporati
5、on. Coloured waste waters shall be examined in accordance with method DIN 38 405 - D 5 - 2. 1.2 Principle of method The cations present in the water sample are exchanged for hydrogen ions using an ion exchanger. The sulfate ions present in the water sample are precipitated in the filtrate as barium
6、sulfate by means of barium ions; the excess of barium ions is determined complexometrically. The sulfate ion concentration is calculated from the difference in the volumes of the initially added and back- titrated barium ion solution. 1.3 Interference Turbidities of the water sample can interfere wi
7、th the determination and shall be eliminated by filtration. Sulfite ionsare partially also covered by the determination; these shall be eliminated by boiling the acidified sample for ten minutes (see subciause 1.8). The phosphate concentrations usually occurring in the waters described in subclause
8、1.1 do not cause interference. 1.4 Designation Designation of the method of determining sulfate ions (D 5) by complexometric titration ( 11 : Method DIN 38 405 - D 5 - 1 1.5 Apparatus The following apparatus shall be used: - exchanger column with cock, 200 mm long, 15 mm - glass wool; in diameter; -
9、 volumetric flask, 1000 mt nominal volume, e.g. DIN 12664 - MS A 1000 volumetric flask; - graduated cylinder, 100 ml nominal volume, e.9. DIN 12680 - ME 100 graduated cylinder; - conical flask, 250 ml nominal volume, e.g. DIN 12385 -WE 250 flask; - graduated pipette, 10 ml nominal volume, e.g, DIN 1
10、2697 - MPAS 10 - O1 pipette; - burette, 25 ml nominal volume, e.g. DIN 12 700 - SGAS - 25 - 005 burette. 1.6 Reagents Only reagents of analytical grade, and only distilled water or water of equivalent purity shall be used. 1.6.1 Ion exchanger, strongly acidic, 0,l to 0.25 mm particle size. 1.6.2 Hyd
11、rochloric acid, c (HCL) = 2.5 mol/l: add 100 ml of hydrochloric acid, c (HCI) = 5 mol/, to 100 ml of water. 1.6.3 Ammonia solution, g (“3) = 0.91 g/ml. 1.6.4 Ammonium chloride, NH4Cl. 1.6.5 Hydroxylammonium chloride, HONH3Cl. 1.6.6 Ethanol, C2H5OH, w = 95%. 1.6.7 Barium chloride solution, c = 8,02,
12、mol/l: dissolve 4,886 g of barium chloride, Bac12 . 2 H20, in water; make up to 1000 ml with water in a volumetric flask; determine the precise concentration by titration as described in subclause 1.8. 1.6.8 EDTA solution, c = 0.02 mol/l: dissolve 7,444 g of the disodium salt of ethylenediaminetetra
13、acetic acid, C1oH14N208Na2.2 H20, in water; make up to 1000 ml with water in a volumetric flask. 1.6.9 Dipotassium magnesium ethylendiaminetetra- acetate, C10H1-2 N208 K2 Mg. 1.6.10 Buffer solution (ph value: 11,4): dissolve 5 g of dipotassium magnesium ethylenediaminetetra-acetate, (as in subclause
14、 1.6.9) in 100 ml of water; add this Continued on pages 2 to 4 Beuih Verlag GrnbH. Berlin 30. has exclusive sale rights for German Standards (DIN-Normen) DIN 38 405 Part 5 Engl. Price group 5 Sales No. 0105 12.85 Page 2 DIN 38 405 Part 5 solution to a solution of 35 g of ammonium chloride (as in sub
15、clause 1.6.4) in 900 ml of ammonia solution (as in subclause 1.6.3). 1.6.11 Eriochrome black T. CmH12N3NaO;rS. 1.6.12 Indicator solution: dissolve 0,5 g of eriochrome black T and 4,5 g of hydroxylammonium chloride (as in subclause 1.6.5) in 100 ml of ethanol. The solution is stable for about 2 weeks
16、. 1.7 Preparation of exchanger column Put a glasswool plug into the exchanger column and charge it with the cation exchanger to a height of 150 mm. Then convert the column charge into the HC form or regenerate it with 100ml of hydrochloric acid (as in sub- clause 1.6.2) at a flow rate of 3 to 4 drop
17、s per second and then wash with water at the same flow rate until the water running out shows a neutral reaction. 1.8 Procedure Filter 150 to 200 ml of the water sample at a flow rate of 3 to 4 drops per second using the prepared exchanger column . Discard the first 50 ml of the eluate, and pipette
18、100 ml of the remainder into a conical flask, heat this to the boil and add 25 ml of barium chloride solution (as in sub- clause 1.6.7). Note. If sulfite is present, leave the solution to stand for 1 O minutes before adding the barium chloride solution. Boil the solution for a few minutes and keep i
19、t hot for about 15 minutes. After 1 to 2 hours, add 4 ml of buffer solution (as in subclause 1.6.10) and 7 drops of indicator solution (as in subclause 1.6.12). Titrate with EDTA solution (as in subclause 1.6.8). until the colour of the indicator has changed to pure blue. Note. Equivalent indication
20、 methods can be used. 1.9 Evaluation The mass concentration of sulfate ions in the water sample shall be calculated using equation ( 1) : (CB VB) - (CT VT) f (1) VP = where ,!3 is the mass concentration of sulfate ions in the water sample, in mg/; VB is the volume of the barium chloride solution add
21、ed, in ml; VT is the volume of the EDTA solution consumed during titration, in ml; CB is the amount of substance concentration of the barium chloride solution, in mol/l; CT is the amount of substance concentration of the EDTA solution, in mol/; f is the equivalence factor: f = 96 . IO3 mg/rnol; Vp i
22、s the volume of the water sample, in L. 1.10 Expression of result The values rounded to 1 mg/l shall be stated to a maximum of 2 significant places. Example: Sulfate ions (SO:-): 53 mg/l. 1.1 1 Test report The test report shall refer to this method and include the following details: a) precise ident
23、ification of the water sample; b) expression of result as given in subclause 1 .IO; c) any deviation from this specification and indication of any circumstances which may have influenced the resu It. 2 Gravimetric determination of sulfate ions 2.1 Field of application The method is directly applicab
24、le to waters and waste waters having a higher sulfate ion content (exceeding 100 mg/l). Water samples with a lower sulfate ion content shall be concentrated by evaporation. 22 Principle of method Sulfate ions are precipitated as barium sulfate by means of barium ions in a hydrochloric acid solution.
25、 2.3 Interference Silicia (exceeding 25 mg/L of Si021 and undissolved substances interfere with the determination. Organic substances (COD exceeding 30 mg/() and dissolved iron(II1) ions (exceeding 10 mg/l of Fe) can interfere. Organic substances shall be removed by shaking with sulfate-free active
26、charcoal and subsequent filtration using a glass fibre filter. In the absence of organically bound sulfur, organic substances and silica can be removed as follows. Pipette 100 rnl of the water sample into a platinum dish and evaporate on a water bath almost to dryness. Add a few ml of hydrochloric a
27、cid (as in subclause 2.6.1) and 5 drops of sodium chloride solution (as in subclause 2.6.2) and, by tilting the dish, bring the substance adhering to the rim of the dish into contact with the hydrochlorid acid, evaporate the contents to dryness and ignite the residue at dull red heat. Moisten the re
28、sidue with 3 ml of water and a few drops of hydrochloric acid (as in subclause 2.6.1) and again evaporate to dryness. Heat the residue now remaining with 3 ml of water and 1 ml of hydrochloric acid (as in subclause 2.6.1), dilute with hot water and filter. Rinse the filter, containing the residue, w
29、ith hot water, until the filtrate is free of chloride ions. Further treat the filtrate and washing water as specified in subclause 2.7. 2.4 Designation Designation of the method of determining sulfate ions (D 5) by gravimetric precipitation with barium ions (2): Method DIN 38405 - D5 -2 DIN 38405 Pa
30、rt 5 Page 3 x-soll ;ample Method 1. N Outliers mg, % K 9 36 10.0 41.61 - 8 32 20,O 138,70 Complexo- metric - M 10 40 O 288.50 G 10 38 O 208.20 - 10 36 O 576.00 Gravi- metric - J 9 33 13.2 1152.00 2.5 Apparatus The following apparatus shall be used: - platinum dish; - platinum or porcelain crucible;
31、- glass beaker, 250 ml nominal volume, e.g. DIN 12331 - HF 250 beaker; - volumetric flask, 100 rnl nominal volume, e.g. DIN 12664 - MS A 100 volumetric flask; - one-mark bulb pipette, 100 ml nominal volume. e.g. DIN 12691 - VPAS 100 pipette; - graduated pipette, 10 ml nominal volume, e.g. DIN 12 697
32、 - MPAS 10 - O1 pipette; - DIN 53 135 - 2 c filter paper or filter crucible, e.g. DIN 12C09 - 25 PI filter crucible. WFR SR VR SI V/ mg/i Yo mg/l ola mg/l O:, 44.79 107.5 3.1 11 6.9 0.744 1.7 142,98 103,l 2.160 1.5 1,492 1,0 292.41 101.4 4,459 1.5 2,806 1,0 209.71 100.7 6.876 3.3 3,337 1.6 582,73 !0
33、1,2 12,387 2,l 8,403 1.4 1158.91 100.6 11.619 1.0 9,262 0.8 2.6 Reagents Only analytical grade reagents and distilled water or water of equivalent purity shall be used. 2.6.1 Hydrochloric acid, 4 (HCL) = 1,12 g/ml. 2.62 Sodium chloride solution: dissolve 10 g of NaCl in 100 ml of water. 2.6.3 Barium
34、 chloride solution: dissolve 10 g of Bac12 2H20 in water and make up to 100 ml with water. 1 ml of this solution precipitates about 40 mg of sulfate ions. 2.7 Procedure Pipette 100 ml of the water sample, if necessary after pretreatment as described in subclause 2.1 or 2.3, into a glass beaker, neut
35、ralise the sample and acidify it with 1 ml of hydrochloric acid (as in subclause 2.6.1). Heat the solution to the boil and add, with stirring, 25 ml of barium chloride solution (as in subclause 2.6.3). Boil the mixture for a few minutes and then keep it hot for about 15 minutes; the precipitate shou
36、ld have settled in a coarse-grained form. After at least 2 Ilours, filter the precipitate off using a washed paper filter or a weighed filter crucible. Wash the filter residue with water until the filtrate is free of chloride ions. Ignite the precipitate at 70OOC in a platinum or porcelain crucible
37、(or in a filter crucible if used) to constant mass. 2.8 Evaluation The mass concentration of sulfate ions in the water sample shall be calculated using equation (2): (2) where p m f V, is the volume of the water sample used, in 1. 2.9 Expression of result The values rounded to 1 mg/l shall be stated
38、 to a maximum of 3 significant places. Example: is the mass concentration of sulfate ions in the water sample, in mg/l; is the mass of barium sulfate; in mg; is the equivalence factor; f = 0,4115; Suifate ions (SO:-) : I 53 mg/L. 2.10 Test report See subclause 1.1 1, reporting the result as specifie
39、d in subclause 2.9. 3 Characteristic data of method An inter-laboratory test carried out in the autumn of 1983 yielded the values given in the following table. Page 4 DIN 38 405 Part 5 Standards referred to DIN 12331 DIN 12385 DIN 12664 Part 1 DIN 12680 Part 1 DIN 12691 DIN 12697 DIN 12700 Part 3 DI
40、N 12909 DIN 53 135 Laboratory glassware; beakers, tall form Laboratory glassware; wide-neck conical flasks Laboratory glassware; one-mark volumetric flasks; volumetric flasks with conical reinforced rim, conical socket and conical ground joint Laboratory glassware; graduated cylinders Laboratory gla
41、ssware; class AS fast delivery one-mark bulb pipettes, waiting time of 15 sec Laboratory glassware; class AS fast delivery graduated pipettes, waiting time of 15 sec Laboratory glassware; burettes; burettes fitted with lateral stopcocks Laboratory porcelainware; filter crucibles Filter paper for che
42、mical analyses; classification, designation, main characteristics, test methods Explanatory notes This standard supersedes the German standard method “Determination of sulfate ions (D 5)“ originally issued by the Study Group Wasserchemie of the Gesellschaft Deutscher Chemiker and contained in the lo
43、ose-leaf publication “Deutsche Einheitsvetfahren zur Wasser-, Abwasser- und Schlammuntersuchung“ (German standard methods for the examination of water, waste water and sludge) published by Verlag Chemie GmbH, Weinheim. All standard methods contained up to now in the above-mentioned loose-leaf public
44、ation will be successively incorporated in the body of German Standards, so that, after a transition period, all standard methods will be available as DIN Standards. Standard methods published as DIN Standards can be obtained from Beuth Verlag GmbH either individually or grouped in volumes. The abov
45、e-mentioned loose-leaf publication by Verlag Chemie GmbH will continue to be published separately incorporating the standard methods. Existing or additional standards or standard methods for the examination of water, waste water and sludge will in future be prepared jointly by the NormenausschuR Was
46、serwesen (NAW) of DIN and the Study Group Wasserchemie and pub- lished as DIN Standards. Standards or draft standards bearing the group title “German standard methods for the examination of water, waste water and sludge“ are classified under the following categories (main titles): General data (grou
47、p A) (DIN 38402) Physical and physico-chemical characteristics (group C) (DIN 38404) Anions (group D) (DIN 38405) Cations (group E) (DIN 38406) Jointly determinable substances (group F) (DIN 38407) Gaseous constituents (group G) (DIN 38408) Summary indices of actions and substances (group H) (DIN 38
48、409) Microbiological methods (group K) (DIN 38411) Test methods using water organisms (group L) (DIN 38412) Individual components (group P) (DIN 38413) Sludge and sediments (group S) (DIN 38414) Information on parts of this standard that have already been published can be obtained from the office of the Mormen- ausschu Wasserwesen fNAWl, DIN Deutsches Institut fr Normung e.V., telephone (030) 2601-423, or from Beuth Verlag Gmb H, Postfach 1 1 07, D -1 O00 Berlin 30. International Patent Classification G O1 N 33-18
