DIN 54402-2009 Testing of ion exchangers - Determination of the total capacity of anion exchangers《离子交换剂的测试 阳离子交换剂总效能的测定》.pdf

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1、April 2009DEUTSCHE NORM Normenausschuss Materialprfung (NMP) im DINDIN-SprachendienstEnglish price group 11No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sal

2、e for German Standards (DIN-Normen).ICS 71.100.40!$a4“1621799www.din.deDDIN 54402Testing of ion exchangers Determination of the total capacity of anion exchangersEnglish translation of DIN 54402:2009-04Prfung von Ionenaustauschern Bestimmung der Totalen Kapazitt von AnionenaustauschernEnglische bers

3、etzung von DIN 54402:2009-04Essai des changeurs dions Dtermination de la capacit totale des changeurs danionsTraduction anglaise de DIN 54402:2009-04SupersedesDIN 54402:2001-12www.beuth.deDocument comprises pages1909.11 DIN 54402:2009-04 2 A comma is used as the decimal marker. Contents Page Forewor

4、d. 3 1 Scope 4 2 Normative references 4 3 Terms and definitions. 4 4 Unit 4 5 Principle . 4 5.1 General . 4 5.2 Strongly basic exchangers and exchangers of mixed basic strength 5 5.2.1 General . 5 5.2.2 Active strong base capacity. 5 5.2.3 Strong base capacity 5 5.2.4 Weak base capacity 5 5.2.5 Tota

5、l capacity 5 5.3 Weakly basic exchangers. 6 5.3.1 General . 6 5.3.2 Total capacity 6 6 Designation 6 7 Apparatus. 6 8 Reagents 8 9 Sampling 8 10 Sample preparation (see flowcharts 1 and 2). 9 10.1 Strongly basic exchangers 9 10.2 Weakly basic exchangers. 9 11 Volume adjustment . 9 12 Determining the

6、 capacities of strongly basic exchangers (method A) . 9 12.1 Determination of the active strong base capacity (flowchart 1) 9 12.2 Determination of the strong base capacity (see flowchart 1). 10 12.3 Determination of the weak base capacity (see flowchart 2) . 11 13 Determination and evaluation of th

7、e weak base capacity of weakly basic anion exchangers (method B) (see flowchart 2). 13 14 Rapid method of determining the total capacity of strongly basic anion exchangers (method C) . 15 14.1 Reagents 15 14.1.1 Sample preparation. 15 14.1.2 Determining the total capacity. 15 14.2 Apparatus. 15 14.2

8、.1 Sample preparation. 15 14.2.2 Determining the total capacity. 15 14.3 Apparatus settings 16 14.3.1 Sample preparation. 16 14.3.2 Determining the total capacity. 16 14.4 Procedure. 16 14.4.1 Sample preparation. 16 14.4.2 Determining the total capacity. 17 14.5 Calculation of total capacity (KT) in

9、 mol/l exchanger 17 15 Test report 19 DIN 54402:2009-04 3 Foreword This standard has been prepared by Working Committee NA 062-08-95 AA Prfung von Ionenaustauschern of the Normenausschuss Materialprfung (Materials Testing Standards Committee). The symbol % is used in this standard to mean percentage

10、 by mass. Amendments This standard differs from DIN 54402:2001-12 as follows: a) Clause 15 has been revised; b) the standard has been editorially revised. Previous editions DIN 54402: 1980-08, 1985-07, 2001-12 DIN 54402:2009-04 4 1 Scope This standard specifies methods for determining the total capa

11、city of anion exchangers (in this standard referred to as “exchangers”, for short). The methods A, B and C according to this standard can be applied to all granular types of strongly and weakly basic exchangers, but not to ground or liquid anion-exchange material. Determination of total capacity ena

12、bles the external observation of anion-exchange material that is used in water treatment equipment using laboratory tests to evaluate changes and decide whether it has undergone any alterations. The parameters determined in the analyses provide information about the total number of groups capable of

13、 exchange, about their basicity and about any changes in these characteristics. 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 re

14、ferenced document (including any amendments) applies. DIN 54400, Ion exchange Terminology DIN 54401, Testing of ion exchangers (bead form) Sampling DIN 54403, Testing of ion exchangers Determination of the total capacity of cation exchangers 3 Terms and definitions For the purposes of this standard,

15、 the terms and definitions given in DIN 54400 apply. 4 Unit The unit in which all capacities in this standard are expressed is mol per litre. 5 Principle 5.1 General Method A (see Clause 12) and method B (see Clause 13) specified in this standard serve to characterize and test anion exchangers and m

16、ake use of the following reactions: the regeneration, with varying efficiency, of groups of different basicity with sodium hydroxide solution; the conversion of neutral salts into hydroxides by strongly basic groups in the hydroxide form; the displacement of chloride ions from the exchanger by nitra

17、te ions; the binding of anions in acidic solution only by weakly basic groups in the regenerated form, i.e. as free bases. DIN 54402:2009-04 5 To determine capacity it is necessary to start from the chloride form in the case of strongly basic exchangers and from the free-base form in the case of wea

18、kly basic exchangers. If the exchanger were loaded with other ions, incorrect capacity values would be obtained because the swelling varies for individual anions. Contamination of the exchangers by deposits, adsorbed oil or other organic substances during operation may alter their total capacity. La

19、boratory determination of the capacity prior to and after cleaning treatment provides information about the cleaning efficiency and the improvement in the parameters achieved. To assess the damage to the exchanger as a result of degradation of the matrix structure or of the functional groups, the cl

20、eaned sample shall always be compared with a sample of unused exchanger from the same batch. 5.2 Strongly basic exchangers and exchangers of mixed basic strength 5.2.1 General Strongly basic exchangers and those of mixed basic strength exhibit gradations in basicity that are due in part to the struc

21、ture of the anion exchanger. The strongly basic exchangers are classified, for example, into those of type I (benzyltrimethylammonium compounds) and those of type II (benzyl(2-hydroxyethyl)dimethylammonium compounds). There are also exchangers of mixed basic strength that contain strongly and weakly

22、 basic groups. These are to be tested in the same way as strongly basic exchangers. Strongly basic exchangers cannot be converted completely to the hydroxide form even by treating them with excess sodium hydroxide. The fraction converted is referred to as the anionic active strong base capacity (sal

23、t-splitting capacity). 5.2.2 Active strong base capacity The chloride form of the exchanger is treated with sodium hydroxide solution under specified conditions and then rinsed with deionized water. Excess sodium chloride solution is then introduced and the active strong base capacity is calculated

24、from the quantity of liberated hydroxide ions in the effluent. 5.2.3 Strong base capacity After rinsing out the excess sodium chloride with deionized water, the exchanger is treated with excess sodium nitrate solution and the strong base capacity is calculated from the quantity of liberated chloride

25、 in the effluent. The strong base capacity is the total number of strongly basic groups in a strongly basic anion exchanger, whereas the active strong base capacity represents only a fraction of the strong base capacity. WARNING Due to the risk of explosion, do not allow anion exchanger in the nitra

26、te form to dry out. 5.2.4 Weak base capacity After the excess sodium nitrate has been rinsed out with deionized water, the exchanger is treated with excess hydrochloric acid and the weak base capacity is calculated from the quantity of hydrochloric acid bound. 5.2.5 Total capacity The total capacity

27、 of strongly basic anion exchangers is obtained by adding the strong and weak base capacities. DIN 54402:2009-04 6 5.3 Weakly basic exchangers 5.3.1 General Only the total capacity is determined in the case of weakly basic and predominantly weakly basic exchangers. Since the volumes of the salt form

28、 and free-base form of some weakly basic exchangers vary considerably owing to the exchanger swelling and shrinkage, they are always converted to the free-base form using sodium hydroxide before testing. Weakly basic exchangers in the chloride form tend to hydrolyse when rinsed with deionized water,

29、 thereby producing hydrochloric acid. To suppress this reaction, which results in values of total capacity that are too low, exchangers in the chloride form shall be washed through with methanol. 5.3.2 Total capacity After the exchanger has been regenerated with excess sodium hydroxide and rinsed wi

30、th deionized water, its volume shall be measured. The exchanger shall then be treated with excess hydrochloric acid and the total capacity shall be calculated from the quantity of hydrochloric acid bound. 6 Designation Designation of the method of determining the total capacity of anion exchangers b

31、y method A: Test DIN 54402-A 7 Apparatus In addition to calibrated measuring instruments and standard laboratory equipment, the following shall be used: Glass filter tube (1) (as shown in Figure 1), with an internal diameter of about 20 mm, about 400 mm long, having a permanently fitted glass frit G

32、0 (2) with a pore size of 150 m to 200 m, a ground socket (3) and a connecting piece (4) about 20 mm long with an internal diameter of 4 mm and an external diameter of about 8 mm. PE tube (5), having an internal diameter of 6 mm and about 450 mm long, connected to the connecting piece (4); the other

33、 end of the PE tube is fitted with a shaped glass piece (6) having an internal diameter of 4 mm and about 100 mm long; a glass tube is fused to the centre of the glass piece extending initially at an angle of about 45 and then at about 20; if the glass piece is suspended in the opening of a vessel (

34、e.g. a volumetric flask) placed on a platform whose height can be adjusted, the liquid level above the ion exchanger packed into the filter tube can be adjusted as necessary (e.g. 1 cm deep) by raising and lowering the shaped glass piece (6). Dropping funnel (7), having a capacity of 500 ml or 1 000

35、 ml is mounted on the filter tube (1) and has a stopcock with a PTFE tap (8) and a conical ground socket. It is advantageous if the extension of this funnel (9), about 60 mm long, is either tapered down to an opening of 1 mm to 2 mm diameter at its end or is a capillary of the same internal diameter

36、 over its entire length. NOTE The apparatus described here is identical to that specified in DIN 54403. Shaking table, for mechanically adjusting the volume DIN 54402:2009-04 Dimensions in millimetres Key 1 Filter tube 2 Glass frit 3 Ground socket 4 Connecting piece 5 PE tube 6 Shaped glass piece 7

37、Dropping funnel 8 Stopcock with tap 9 Extension Figure 1 Filter tube 7 DIN 54402:2009-04 8 8 Reagents Reagents shall be of analytical grade and the water used shall be fully demineralized using ion exchangers. Unless otherwise specified, the solutions of reagents shall be prepared with deionized wat

38、er. Analytical grade methanol, CH3OH; 0,1 % solution of methyl orange in ethanol; mixed indicator, for the chloride determination: prepared by dissolving 0,2 g of 1,5-diphenylcarbazone and 0,02 g of bromophenol blue in 96 % (V/V) ethanol and making up to 100 ml; 2,5 % sodium chloride solution: prepa

39、red by dissolving 25 g of sodium chloride, NaCl, in deionized water and making up to 1 000 ml; sodium chloride solution with 1 mg chloride per 1 ml: prepared by dissolving 1,648 5 g of analytical grade sodium chloride, NaCl, dried at (110 5) C, in deionized water in a 1 000 ml volumetric flask and m

40、aking up to the mark. 1 ml of this solution contains 1 mg of chloride; 2 % sodium hydroxide solution: prepared by dissolving 20 g of sodium hydroxide, NaOH, in deionized water and making up to 1 000 ml; c(NaOH) = 1 mol/l sodium hydroxide solution; c(NaOH) = 0,1 mol/l sodium hydroxide solution; 2,5 %

41、 sodium nitrate solution: prepared by dissolving 25 g of sodium nitrate, NaNO3, in deionized water and making up to 1 000 ml; 0,1 % phenolphthalein solution in ethanol; mercury(II) nitrate solution: prepared by dissolving 4,65 g of mercury(II) nitrate, Hg(NO3)2, in 1,5 ml of nitric acid (of density

42、1,42 g/mol at 20 C) while heating to not more than 40 C in a 1 000 ml volumetric flask and making up to the mark with deionized water after cooling to ambient temperature. The titrimetric factor, , of this solution shall be determined by titrating the sodium chloride solution with a chloride concent

43、ration of 1 mg/ml; c(HNO3) = 0,05 mol/l nitric acid; 1 % hydrochloric acid; c(HCl) = 1 mol/l hydrochloric acid; c(HCl) = 0,1 mol/l hydrochloric acid. 9 Sampling According to DIN 54401. DIN 54402:2009-04 10 Sample preparation (see flowcharts 1 and 2) 10.1 Strongly basic exchangers To determine the to

44、tal capacity, convert the strongly basic exchanger to the chloride form. To do this, fill the filter tube with deionized water and introduce about 100 ml of the sample in any chemical form without allowing bubbles to form and pass about 2 000 ml of 1 % hydrochloric acid through it at a flow rate of

45、20 ml/min. Then wash with deionized water at the same flow rate until the base capacity of the effluent at a pH value of 4,3 (KB4,3) is 0,1 mmol/l. The exchanger will then be in the chloride form. The determination of the capacity should begin within 24 hours. 10.2 Weakly basic exchangers To determi

46、ne the total capacity, the weakly basic exchanger in the free-base form is used. To do this, fill the filter tube with deionized water and introduce about 100 ml of the sample in any chemical form without allowing bubbles to form and pass 1 000 ml of 2 % sodium hydroxide solution through it at a flo

47、w rate of 10 ml/min. Then rinse with deionized water at the same flow rate until the acid capacity of the effluent at a pH value of 8,2 (KS8,2) is 0,1 mmol/l. If this value has not been reached after two hours and no tendency for the acid capacity to decrease is observed, stop the rinsing and make a

48、n appropriate note in the test report. After this treatment, the exchanger will be in the free-base form. The determination of the capacity should begin within 24 hours. 11 Volume adjustment Shake the exchanger pretreated as described in 10.1 or 10.2 under deionized water in a measuring cylinder man

49、ually or, preferably, on a shaking table until the volume is constant, taking care to remove any air bubbles. The final volume of the exchanger after shaking shall be (50 1) ml. 12 Determining the capacities of strongly basic exchangers (method A) 12.1 Determination of the active strong base capacity (flowchart 1) After shaking the exchanger to a constant volume of (50 1) ml as described in Clause 11, use deionized water to transfer it quantitatively to the filter tube filled with deionized water and lower