ASTM D2022-1989(2008) Standard Test Methods of Sampling and Chemical Analysis of Chlorine-Containing Bleaches《含氯漂白剂的抽样和化学分析的标准试验方法》.pdf

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1、Designation: D 2022 89 (Reapproved 2008)Standard Test Methods ofSampling and Chemical Analysis of Chlorine-ContainingBleaches1This standard is issued under the fixed designation D 2022; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisio

2、n, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 These test methods cov

3、er the sampling and chemicalanalysis of chlorine-containing bleaches. The methods appearin the following order:SectionsSodium Hypochlorite (Soda Bleach) Solutions:Sampling 5Available Chlorine 6-9Sodium Chlorate 10-14Total Chlorine 15-18Sodium Chloride 19 and 20Total Alkalinity as Sodium Oxide (Na2O)

4、 21-24Free Alkali as Sodium Hydroxide (NaOH) 25-28Calcium Hypochlorite:Sampling 30Available Chlorine 31-34Water 35-40Chloroisocyanuric Acids and Their Derived Salts:Sampling 42Available Chlorine (IodometricThiosulfate Method) 43-46Available Chlorine (ArseniteIodometric Method) 47-50Moisture 51-541.2

5、 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Material SafetyDa

6、ta Sheets are available for reagents and materials. Reviewthem for hazards prior to usage.2. Referenced Documents2.1 ASTM Standards:2D 1193 Specification for Reagent Water3. Terminology3.1 Definitions:3.1.1 available chlorinethe measure of the oxidizingpowder of the chlorine present as hypochlorite.

7、 It is expressedin terms of chlorine with a gram-equivalent weight of 35.46.4. Reagents4.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of

8、the American Chemical Society,where such specifications are available.3Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.4.2 Unless otherwise indicated, references to water sha

9、ll beunderstood to mean reagent water conforming to SpecificationD 1193.1These test methods are under the jurisdiction of ASTM Committee D12 onSoaps and Other Detergents and are the direct responsibility of SubcommitteeD12.12 on Analysis and Specifications of Soaps, Synthetics, Detergents and theirC

10、omponents.Current edition approved July 1, 2008. Published July 2008. Originally approvedin 1962. Last previous edition approved in 2003 as D 2022 89(2003).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of AST

11、MStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Reagent Chemicals, American Chemical Society Specifications , AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar St

12、andards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.SODIUM

13、 HYPOCHLORITE (SODA BLEACH) SOLUTIONS5. Sampling5.1 The stability of soda bleach is influenced to a consider-able degree by the purity of the alkali used in its preparation,by the excess of alkali remaining, and by the kind and amountof metal contamination from equipment. Owing to the rela-tively un

14、stable nature of bleach solutions, special attentionshall be given to the collection and preservation of the sample.Exposure to heat and sunlight promotes decomposition, andshall be avoided. Samples shall be kept cool in a dark place (orin dark-colored bottles) until analyzed, which shall be donewit

15、hout unnecessary delay.5.2 Strong solutions of bleach shall be accurately dilutedand aliquots taken for determination of available chlorine,chlorate, and total chlorine. The size of aliquots shall be suchthat approximately 40 mL of the 0.1 N reagent is required. Thealkali determinations shall be mad

16、e directly on the samplereceived and sample sizes to require about 10 mL of 0.1 Nreagent are recommended.5.3 Precision results will require sampling at a standardtemperature such as 20C. Results expressed in terms of weightpercent will require determination of the density or specificgravity. This ma

17、y be determined with a hydrometer or byweighing the sample, after pipetting the amount to be dilutedfor analysis into a tared weighing bottle. The weighed samplemay be transferred to a volumetric flask and used for subse-quent analysis.AVAILABLE CHLORINE6. Summary of Test Method6.1 The sample is add

18、ed to an acidified solution of potas-sium iodide and the released iodine is titrated with standardsodium thiosulfate solution to the usual starch end point.7. Reagents7.1 Acetic Acid, glacial.7.2 Potassium Iodide (KI), crystals, iodate-free.7.3 Sodium Thiosulfate Solution Standard, (0.1 N)Dissolve 2

19、5 g of sodium thiosulfate (Na2S2O35H2O) crystalsin freshly boiled and cooled water and dilute to 1 L. Thesolution is more stable if the glassware is cleaned withsulfuric-chromic acid and thoroughly rinsed with water. Stan-dardize against potassium iodate as follows: Weigh out accu-rately 3.567 g of

20、dry potassium iodate (KIO3) and transfer to a1-L volumetric flask. Dissolve with water, make up to themark, and mix thoroughly. This solution will be exactly 0.1000N. To standardize the Na2S2O3solution, carefully pipet a 50-mL aliquot of the KIO3solution into a 250-mL Erlenmeyerflask and dilute to 1

21、00 mL with water. Add1gofKIcrystals.When it is dissolved, add 15 mL of 1.0 N hydrochloric acid andtitrate immediately with the Na2S2O3solution. When the solu-tion becomes light yellow, add 1 mL of starch indicatorsolution and complete the titration to the disappearance of theblue color. Standardize

22、at least monthly. Calculate the normal-ity of the Na2S2O3solution as follows:Normality 5 50 3 0.1!/A (1)where:A =Na2S2O3solution required for titration of theKIO3solution, mL.7.4 Starch Indicator Solution (0.5 %)Mix 0.5 g of solublestarch with 5 mL of cold water and add to 95 mL of boilingwater. Mix

23、, cool, and store in a sterilized bottle. Replacefrequently or add 0.1 % salicylic acid to minimize deteriora-tion.8. Procedure8.1 Dissolve 2 to3gofKIcrystals in 50 mL of water in a250-mL Erlenmeyer flask.Add 10 mL of acetic acid, then pipetthe aliquot of sample into the solution, keeping the tip of

24、 thepipet beneath the surface of the solution until drained. Titrate atonce with 0.1 N Na2S2O3solution until the iodine color isnearly gone, then add 1 mL of starch indicator solution andcomplete the titration to the disappearance of the blue color.Record the titration as A (see Section 14).9. Calcu

25、lation9.1 Calculate the available chlorine as follows:Available chlorine as Cl, g/L 5 AN 3 35.46!/V (2)Available chlorine as Cl, weight % 5 AN 3 0.03546!/VS 3 1009.2 Calculate the sodium hypochlorite content as follows:Sodium hypochlorite NaOCl!, g/L 5 AN 3 37.22!/V (3)Sodium hypochlorite NaOCl!, we

26、ight %5 AN 3 0.03722!/VS 3 100where:A =Na2S2O3solution required for titration of the sample,mLN = normality of the Na2S2O3solution,V = original sample in aliquot used, mL, andS = specific gravity of the sample.SODIUM CHLORATE10. Summary of Test Method10.1 Sodium chlorate is reduced with sodium bromi

27、de in 8N hydrochloric acid.4,5After dilution and addition of potassiumiodide, the released iodine (equivalent to the hypochlorite pluschlorate) is titrated with standard sodium thiosulfate solutionand starch indicator.11. Apparatus11.1 The apparatus (Fig. 1) consists of 1-L wide-mouthreaction vessel

28、, A (a 1-qt fruit jar will serve), fitted with a 2-hole rubber stopper carrying a separatory funnel, B, conve-niently graduated or marked at the 10, 20, and 100-mL levels,4Ditz, Hugo, “Determination of Chlorates in Electrolytic Bleaching Lyes and inLyes Obtained from Absorption Vessels During the Pr

29、oduction of PotassiumChlorate,” Chemiker Zeitung, Vol 25, 1901 p. 727.5White, J. F., “Determination of Available Chlorine in Solutions ContainingTextone (NaClO2),” American Dye-stuff Reporter, Vol 31, 1942 pp. 4847.D 2022 89 (2008)2and a delivery tube leading to a 50-mL test-tube gas trap, C,which i

30、s fitted with rubber tubing and a glass mouthpiece, D.12. Reagents12.1 Hydrochloric Acid (sp gr 1.42)Concentrated hydro-chloric acid (HCl). For highest accuracy, it should be checkedfor the presence of oxidizing or reducing matter. When used foran analysis of pure potassium chlorate (KClO3) by this

31、method,there should be no fading or return of the end point, and theassay error should not exceed 60.5 %.12.2 Sodium Bromide Solution (10 %)Prepare a 10 %solution of sodium bromide (NaBr).12.3 Potassium Iodide Solution (10 %)Prepare a 10 %solution of potassium iodide (KI). Decolorize withNa2S2O3when

32、 necessary.12.4 Sodium Thiosulfate Solution Standard, (0.1 N)See7.3.12.5 Starch Indicator Solution (0.5 %)See 7.4.13. Procedure13.1 Pipet an aliquot of the sample (same amount as usedfor available chlorine determination, Sections 6-9) into thereaction vessel. Assemble the apparatus and put 25 mL of

33、KIsolution in the gas trap. Close the funnel stopcock, pour 20 mLof NaBr solution into the funnel, open the stopcock, and withgentle suction on the mouthpiece, draw the NaBr solution intothe sample. Close the stopcock and pour 100 mL of HCl intothe funnel. Open the stopcock and allow the acid to dra

34、in intothe sample. Draw in the last drops with suction, close thestopcock, swirl the vessel to mix the acid, and let stand exactly5 min (use time clock). There will be a tendency for a vacuumto form and draw KI solution from the trap back into thesample. This must be avoided by filling the funnel wi

35、th waterand relieving the vacuum by opening the stopcock and addinga small amount of water.13.2 After 5 min, open the stopcock and allow the water todrain into the sample, swirling to dilute the acid. Add waterthrough the funnel sufficient to dilute the sample to about 700mL. Close the stopcock, and

36、 add 10 mL of KI solution to thefunnel. Apply pressure at the mouthpiece to blow the contentsof the trap back into the vessel, opening the stopcock to allowthe necessary amount of gas to escape through the funnel.Rinse the trap twice with water, each time blowing the contentsinto the vessel as above

37、. Finally, allow the contents of thefunnel to drain into the vessel, rinse down the funnel andstopper, and thoroughly mix the contents of the vessel. Titrateat once with 0.1 N Na2S2O3solution. When the iodine color isnearly gone, add 5 mL of starch indicator solution andcomplete the titration to the

38、 disappearance of the blue color.Record the titration as B.14. Calculation14.1 Calculate the sodium chlorate content as follows:Sodium chlorate NaClO3!, g/L 5 B A!N 3 17.74/V (4)Sodium chlorate NaClO3!, weight %B A!N 3 0.01774VS3 100where:A =Na2S2O3solution required for titration for availablechlori

39、ne (Section 8), mLB =Na2S2O3solution required for titration for sodiumchlorate (Section 13), mLN = normality of the Na2S2O3solution,V = original sample in aliquot used, mL, andS = specific gravity of the sample.TOTAL CHLORINE15. Summary of Test Method15.1 All hypochlorite and chlorate present is red

40、uced tochloride by sodium metabisulfite in the presence of nitric acid.The total chloride is then determined by a standard Volhardtitration.16. Reagents16.1 Iron Indicator SolutionDissolve 6.25 g of ferricammonium sulfate (Fe2(SO4)3 (NH4)2SO424H2O) in 50 mLof water and add 45 mL of HNO3.16.2 Nitric

41、Acid, (sp gr 1.42)Concentrated nitric acid(HNO3).16.3 Potassium Thiocyanate Solution Standard, (0.05 N)Prepare a 0.05 N solution of potassium thiocyanate (KCNS)and standardize against 0.05 N AgNO3solution.16.4 Silver Nitrate Solution Standard (0.05 N)Prepare a0.05 N solution of silver nitrate (AgNO3

42、) and standardizeagainst sodium chloride (NaCl) by Mohrs Method (K2CrO4indicator). 2.923 g of NaCl dissolved and diluted to exactly1000 mL yields a solution exactly 0.0500 N.16.5 Sodium Metabisulfite(Na2S2O5), powder.17. Procedure17.1 To a 250-mL beaker add 50 mL of water and about 0.5gofNa2S2O5powd

43、er. Then pipet into the mixture a samplealiquot of the same size as used for available chlorine andchlorate. Add about 10 drops of HNO3to acidify the solutionand boil until all the SO2has been expelled. Cool to roomtemperature and add 5 mL of iron indicator solution. From aFIG. 1 Apparatus for Deter

44、mination of Sodium Chlorate inSodium Hypochlorite (Soda Bleach) SolutionsD 2022 89 (2008)3buret add 0.5 mL of 0.05 N KCNS solution (Note 1). Thentitrate to complete decolorization with 0.05 N AgNO3solution.Filter off the precipitate by suction and wash three times withwater. Finally, back-titrate th

45、e filtrate and washings with 0.05 NKCNS solution until a faint reddish color persists. For lessaccurate work the filtration may be avoided by adding 1 mL ofnitrobenzene to coagulate the suspension before back-titratingthe excess AgNO3.NOTE 1This small amount of KCNS solution serves as an indicator t

46、oshow when an excess of AgNO3solution has been added. The backtitration is continued from the same buret and the total volume of KCNSsolution used is noted and used in the calculation.18. Calculation18.1 Calculate the total chlorine content as follows:Total Chlorine as Cl, g/L 5 CN1! DN2! 3 35.46/V

47、(5)Total chlorine as Cl, weight %5CN1! DN2!3 0.03546VS3 100where:C = AgNO3solution required for titration of the sample,mL,D = KCNS solution required for back-titration, total mLN1= normality of the AgNO3solution,N2= normality of the KCNS solution,V = original sample in aliquot used, mL, andS = spec

48、ific gravity of the sample.SODIUM CHLORIDE19. Summary of Test Method19.1 Any chlorine present as a sodium chloride is deter-mined by calculation as the difference between the totalchlorine and the sum of the chlorine present as hypochloriteand as chlorate.20. Calculation20.1 Calculate the sodium chl

49、oride content as follows:Sodium chloride NaCl!, g/L 5 E F/2! G/3!# 3 1.649 (6)Sodium chloride NaCl!, weight % 5 J K/2! L/3!# 3 1.649where:E = total chlorine, g/L (Section 18),F = available chlorine, g/L (Section 9),G = sodium chlorate, g/L (Section 14),J = total chlorine, in weight percent (Section 18),K = available chlorine, in weight percent (Section 9), andL = sodium chlorate, in weight percent (Section 14).TOTALALKALINITY AS SODIUM OXIDE (Na2O)21. Summary of Test Method21.1 A sample is added to neutralized