1、UDC 628.1/.3 : 620.1 : 628.336.1 : 543.3 : 546.18 DEUTSCHE NORM German standard methods for the examination of water, waste water and sludge Sludge and sediments (group S) Determination of phosphorus in sludges and sediments (S 12) November 1986 DIN 38 414 Part 12 Deutsche Einheitsverfahren zur Wass
2、er-, Abwasser- und Schlammuntersuchung; Schlamm und Sedimente (Gruppe S); Bestimmung von Phosphor in Schlmmen und Sedimenten (s 12) In keeping with current practice in standards published by the International Organization for Standardization (ISO), a comma has been used throughout as the decimal mar
3、ker. This standard has been prepared jointly with Study Group Wasserchemie (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 connectio
4、n with the analyses specified in this standard 1 Field of application This standard is intended to serve as the basis for the analysis of the dry mass of sludges and sediments obtained as specified in DIN 3841 4 Part 2 *). Wet sludges can be analysed by determining the various phosphorus com- pounds
5、 dissolved in the sludge water by the method given in DIN 38 405 Part 11. For this purpose, it is necessary to separate the water from the sludge. 2 Scope The method described in this standard serves to dissolve the greater part of phosphorus compounds present in the dry mass. Their total concentrat
6、ion can then be deter- mined by the method specified in DIN 38 405 Part 1 I. 3 Principle Phosphorus compounds may be present in sludges and sediments in various forms. For analysis these are decomposed by oxidation. The phosphorus compounds are then available in soluble form as phosphate, which allo
7、ws their total concentration to be determined photometrically by the method specified in DIN 38405 Part 11. 4 Interference See DIN 38405 Part 11. 5 Designation The method of acid decomposition of the dry mass of sludges and sediments for determining the concentration of acid-soluble phosphorus compo
8、unds (S 12) shall be designated as follows: Method DIN 38414 - S 12 *) When the analysis is carried out, it should be borne in mind that the analytical results can be particle size-dependen t. 6 Apparatus The following apparatus shall be used. Analytical type mill, e.g. mechanical mortar and pestle.
9、 0,l mm test sieve, e.g. DIN 4188-0,l nr.St test sieve provided with a woven wire cloth. Oven Desiccator of nominal size 200, e.g. DIN 12 491 - 200 desiccator. Reaction vessel of 250 ml nominal capacity, e.g. DIN 12 348 - RANS 250 - 29 flask or DIN 12 387 - E 250 ANS 29 flask. Non-return absorption
10、vessel, e.g. as shown in figure 1. Reflux condenser, of 340 mm assembled length, with conical ground glass joints, e.g. DIN 12 581 - K 250 - 29 condenser. Adjustable heating device. Volumetric flasks of 50, 100 and 500 ml nominal capac- ities, e.g. DIN 12 664 - MSA 50 volumetric flasks. Kjeldahl fla
11、sk of 250 mi nominal capacity, e.g. DIN 12360-250 Kjeldahl flask. Photometer, spectrophotometer or filter photometer with filters for a wavelength of 680 nm or 880 nm. Analytical funnel, 80 mm in diameter, with 110 mm or 125 mm circular filters, medium hard, or with equivalent glass fibre filter. On
12、e-mark bulb pipettes of 1,2,5, IO, 20,50ml nominal capacities, e.g. DIN 12 691 -VPAS 1 pipette or dispenser, e.g. as specified in DIN 12650 Part 3. Glass beads, with roughened surface, 2 to 3 mm in diameter, or equivalent boiling aids. Note. All glass apparatus shall be washed before use with hot hy
13、drochloric acid (as specified in sub- clause 7.?),and then rinsed with water. Detergents containing phosphate shall not be used. The glass apparatus shall be used only for the phosphate determination and stored where it is protected from dust. Glass apparatus coming into contact with the blue comple
14、x that forms in the course of the photometric analysis and which is to be Continued on pages 2 to 4 Beuih Verlag GmbH, Berlin has the excidsive right of sale foi German Standards (DIN-Normen) 07.87 Sales No. 0105 DIN 38 4 14 Part 12 Engl. Price group Page 2 DIN 38414 Part 12 analysed, should be clea
15、ned from time to time using sodium hydroxide solution (20 ml of solution as specified in subclause 7.5 diluted with 180 ml of water) because this complex adheres to the walls as a thin film and is difficult to wash off with water. 7 Reagents The reagents used shall be adequate for the purity require
16、ments of the analyses carried out in accordance with the specifications of this standard. Their purity shall be checked by a blank test (see clause 8). Only double- distilled water or water of equivalent purity shall be used. 7.1 Hydrochloric acid, HCl, e = 1,19 g/ml. 7.2 Nitric acid, “03, e = 1,40
17、g/ml. 7.3 Nitric acid, c(HNOg), e = 0,5 moi/l: dilute 35 ml of nitric acid (as specified in subclause 7.2) with water to 1 1. Dimensions in mm -07 Four holes, about / 1 to 2 mrn in diameter DIN12242-KNS29/32 ground cone Figure 1. Absorption vessel 7.4 Sulfuric acid, H2SO4, e= 1,84 g/ml. 7.5 Sodium h
18、ydroxide solution: dissolve 64 g of sodium hydroxide, NaOH, in 150 ml of water whilst cooling, then dilute with water to 200 ml. Thoroughly mix, cool and store in a polyethylene bottle. 7.6 Ascorbic acid solution: dissolve log of L (+) as- corbic acid, C6H3O6, in 100 ml of water. Store in the dark i
19、n a refrigerator; the solution is stable for several weeks. 7.7 Molybdate reagent solution: dissolve 13 g of ammonium heptamolybdate, (NH4)6M07024 .4 H20, in 100 ml of water, add 200 ml of dilute sulfuric acid (sulfuric acid as specified in subclause 7.4, diluted in a ratio of 1 3). Dissolve 0,35 g
20、of potassium antimony(II1)oxide tartrate, K(SbO)CqH406 0,5 H20, in 100 ml of water, and add this solution to the acid molybdate solution and mix thoroughly. The molybdate reagent solution is stable for at least two months. 8 Procedure 8.1 Method Grind the dry mass of a sludge or sediment obtained by
21、 method DIN 38414-S 2 in the analytical mill to a particle size of 0,l mm. Check on a fraction of the sample taken from the ground material that at least 95 % passes through the sieve;discard this sample. Use a further sample of the ground material for decom. position. For this purpose, dry about 3
22、g of the ground material for 30 minutes in the oven at 105 OC and then weigh it to the nearest 0,Ol g after having cooled it in the desiccator. Moisten this sample with about 2 ml of water in the reaction vessel in a similar manner to that described in DIN 38414 Part 7 and then add one after the oth
23、er, 21 ml of hydrochloric acid (as specified in subclause 7.1) and 7 ml of nitric acid (as specified in subclause 7.2). In the case of strongly foaming substances, the acids should be added carefully by drops. Place 10 ml of nitric acid (as specified in subclause 7.3) in the absorption vessel (see f
24、igure 1) and then connect the vessel to the reflux condenser and the reaction vessel. Allow the vessels to stand with their contents at ambient temperature for at least two hours. Heat the reaction mixture and keep it boiling for about two hours, taking care that the condensation zone does not exten
25、d above the lower third of the reflux condenser. After cooling, transfer the contents of the absorption vessel through the condenser tube to the reaction vessel; rinse the absorption vessel with about 15 ml, and the condenser tube with about 10 ml of nitric acid (as specified in subclause 7.31, tran
26、sferring the acid to the react ion vesse I. Filter the contents of the reaction vessel quantitatively into a 100 ml volumetric flask using an acid-resistant paper or glass fibre filter that has been prewached with nitric acid (as specified in subclause 7.3). Wash the reaction vessel and the filter c
27、ontaining the filtration residue twice, using 10 ml of nitric acid (as specified in subclause 7.3) in each case. Combine the wash liquids with the filtrate and top up the volumetric flask with water (decomposition solu- tion I). Decomposition solutions that are difficult to filter should be separate
28、d from the insoluble matter by sedimentation or centrifugation. Pipette 10 ml (equivalent to 0,30 g of the initial sample mass) of the decomposition solution thus obtained into a 250 ml Kjeldahl flask. Add 2 ml of sulfuric acid (as specified in subclause 7.4) whilst shaking the liquid. After adding
29、the boiling aid, heat the mixture until white vapour is produced. After cooling, carefully add dropwise 0.5 ml of nitric acid (as specified in subclause 7.2) and heat the solution until no further brown vapour is released. After cooling, add a further 0,5 ml of nitric acid (as specified in subclause
30、 7.2); heat the solution again. Repeat the process several times to produce a clear and as far as possible colourless solution. Pour this solution into a 500 ml volumetric flask, rinse the Kjeldahl flask with a little water and add the wash liquid to the solution. Top up with water to the mark (deco
31、mposition solu- tion II), shake thoroughly, take up to 40 ml of the solu- tion (see table 1). pour it into a 50 ml volumetric flask and adjust the pH value to a value between 3 and 10 by adding sodium hydroxide solution (as specified in sub- clause 7.5). Note. Where a series of measurements is made,
32、 the adjustment of the pH value shall, if necessary, be carried out separately using a conical flask. Then, if necessary, top up with water to about 40 ml and, whilst shaking the solution, add 1 ml of ascorbic acid solution (as specified in subclause 7.6) and after about 30 seconds, 2 ml of molybdat
33、e reagent solution (as specified in subclause 7.7). Top up the solution with water to the mark and mix thoroughly. After 10 to 30 minutes determine the absorbance at a wavelength of 680 nm or 880 nm as described in DIN 38 405 Part 11. At the same time as the sample is analysed, carry out a blank tes
34、t, proceeding as described above, but replacing the test portion with 2 ml of water. Equivalent methods of determination may be used; this, however, shall be stated in conjunction with the ex- pression of results. Volume taken from decomposition solutions, in mi 40 30 20 10 5 8.2 Choice of range of
35、detection In contrast to the concentration of phosphorus com- pounds in water, the phosphorus concentration in sludges and sediments can vary within wide limits. Allowance can be made for this when using this method by appro- priately adapting the sampling from decomposition solutionsIand Hasspecifi
36、ed in subclause8.1 (seetable 1). Range of detection of phosphate concentration in the dry matter, in % 0,4 to 8,O 0,6 to 11,0 0,8 to 16,0 1,6 to 32.0 3,2 to 64.0 Table I. Volume taken from decomposition solutions, in mi Decomposition solution II: dissolve 0,30 g of initial mass in 500 rnl of water R
37、ange of detection of phosphate concentration in the dry matter, in % 0,008 to 0,16 0,012 to 0.22 0.01 6 to 0,33 0,033 to 0,66 0,07 to 1.34 DIN 38414Part 12 Page 3 Where the phosphate concentrations in the sludge sample are expected to be lower than the range covered here, the amount taken from decom
38、position solution I should be i ncreased accord i ngl y. In the case of higher phosphate concentrations, aliquot parts of decomposition solution II shall be diluted to 500 ml, e.g. as shown in table 2. 9 Evaluation When an aliquot part of decomposition solution II is taken, the percentage by mass of
39、 phosphate (P) in the dry matter shall be calculated by the following equation: where WP AS A so fs d is the percentage by massof phosphate (P) in the sample; is the absorbance of the sample solution; is the absorbance of the blank solution; is the calibration factor determined in accordance with DI
40、N 38405 Part 11 as the reciprocal of the slope of the calibration function, in mg/l; is the initial mass, in g; is the volume of the test solution, V, = 50 ml; is the aliquot part of the decomposition solution II, in ml; is a factor; here, d = 2. When ai, aliquot part is taken from the diluted decom
41、- position solution II, the value of wp calculated from the above equation shall be multiplied by a factor (e.g. by a factor of 50 in the case of dilution 1 : 49). 1 O Expression of result The values of phosphate concentration in the dry matter, calculated as P, shall be reported as follows: from 0,
42、Ol %to 0,l %: to the nearest 0,001 %; over 0,l % up to 10 %: to the nearest 0.01 %; over 10 % : to the nearest 0.1 %. Page 4 DIN 38414 Part 12 Standards referred to DIN 4188 Part 1 DIN 12 242 Part 1 DIN 12348 DIN 12360 DIN 12387 Sieving media; woven-wire cloth media for test sieves; dimensions Labor
43、atory glassware; interchangeable conical ground joints; dimensions, tolerances Laboratory glassware; round bottom and flat bottom flasks fitted with conical socket; cone 1 : 10 Laboratory glassware; Kjeldahl flasks Laboratory glassware; conical flasks fitted with conical socket; cone 1 : 10 DIN 1249
44、1 DIN 12581 DIN 12550Part 3 DIN 12664Part 1 DIN 12691 DIN 38 405 Part 1 1 DIN 38414Part 2 DIN 38414 Part 7 Laboratory glassware; vacuum desiccators Laboratory glassware; Allihn condensers fitted with conical ground joints Mechanical, physical and electrical laboratory apparatus; piston-operated volu
45、meters; dispensers Laboratory glassware; one-mark volumetric flasks; volumetric flasks with conical reinforced rim. conical socket and conical ground joint Laboratory g1assware;classASfast delivery one-mark bulb pipetteswith a waiting time of 15 seconds German standard methods for the examination of
46、 water, waste water and sludge; anions (group D); determination of phosphorus compounds ID 11) German standard methods for the examination of water, waste water and sludge; sludge and sediments (group S); determination of water content and of dry residue and solids content (S 2) German standard meth
47、ods for theexamination of water, waste water and sludge; sludge and sediments (group S); digestion using aqua regia for subsequent determination of the acid-soluble portion ot metals (S 7) Explanatory notes This standard incorporates the German standard method “Determination of phosphorus in sludges
48、 and sediments (S 12)“ prepared jointly by the Normenausschu Wassetwesen of DIN and Study Group Wasserchemie of the Gesellschaft Deut- scher Chemiker. Apart from such jointly prepared methods, all the standard methods contained up to now in the loose-leaf publication “German standard methods for the
49、 examination of water, waste water and sludge“, published by VCH Verlagsgesellschaft, will be successively incorporated in the body of German standards, so that, after a transition period, all the standard methods will be available as DIN Standards. Standard methods published as DIN Standards are obtainable from Beuth Verlag GmbH either individually or grouped in volumes. The above-mentioned loose-leaf publication, incorporating the standard methods, will also continue to be published by VCH Veriagwesellschaft. Existing and further standards on standard methods for the examination of water
