1、Designation: D 2351 90 (Reapproved 2005)Standard Test Method forSulfide in White Pigment Separated from Solvent-ReduciblePaints1This standard is issued under the fixed designation D 2351; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revis
2、ion, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of sulfidesulfur in white pigment separated from solvent-r
3、educiblepaints.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.3 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 t
4、o establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 215 Practice for the Chemical Analysis of White LinseedOil PaintsD 1193 Specification for Reagent WaterD 2371 Test Method for Pigm
5、ent Content of Solvent-Reducible Paints3. Summary of Test Method3.1 The extracted pigment is placed in a flask with mossyzinc. The hydrogen sulfide generated by addition of HCl reactswith lead nitrate in an absorption flask forming lead sulfide.The lead sulfide is dissolved with nitric acid (HNO3) a
6、nd thelead determined as lead sulfate in accordance with TestMethods D 215.3.2 A rapid method is also described.4. Significance and Use4.1 Sulfide containing pigments such as lithopone have beenused in paints in varying degrees in the past years. As such itis useful to formulators and users to be ab
7、le to monitor theamount of this compound in whole paints.5. Reagents5.1 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 the American Chemic
8、al 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.5.2 Purity of WaterUnless otherwise indicated, referencesto water shall be
9、 understood to mean reagent grade waterconforming to Type II of Specification D 1193.5.3 Ammoniacal Cadmium Chloride or Zinc SulfateSolutionDissolve8gofcadmium chloride (CdCl22H2O) in200 mL of water and add 200 mL of ammonium hydroxide(NH4OH, sp gr 0.90); or, dissolve 200 g of zinc sulfate(ZnSO47H2O
10、) in 1080 mL of water and 920 mL of NH4OH(sp gr 0.90).5.4 Hydrochloric Acid (sp gr 1.19)Concentrated HCl.5.5 Lead Nitrate, Alkaline Solution Into 100 mL ofpotassium hydroxide (KOH) solution (56 g in 140 mL ofwater) pour a saturated solution of lead nitrate (Pb(NO3)2) (250g in 500 mL of water) until
11、the precipitate ceases to redissolve,stirring constantly while mixing. Let settle, filter through aglass filter, and dilute the clear filtrate with an equal volume ofwater. About 3 volumes of the Pb(NO3)2solution will berequired for 1 volume of the KOH solution.5.6 Mossy Zinc.5.7 Nitric Acid (1+4)Mi
12、x 1 volume of concentratedHNO3, (sp gr 1.42) with 4 volumes of water.5.8 Potassium Iodate, Standard SolutionDissolve 3.6 g ofpotassium iodate (KIO3) and 39 g of potassium iodide (KI) in1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Appl
13、ications and is the direct responsibility ofSubcommittee D01.21 on Chemical Analysis of Paints and Paint Materials.Current edition approved Jan. 1, 2005. Published February 2005. Originallyapproved in 1965. Last previous edition approved in 1999 as D 2351 90 (1999).2For referenced ASTM standards, vi
14、sit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washing
15、ton, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.1Copyright A
16、STM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.1 L of water. For general work the theoretical sulfur titer of thissolution should be used; for special work the solution may bestandardized against similar material, such as a lithopone ofknown su
17、lfide sulfur content. The theoretical titer is based onstandard sodium oxalate (Na2C2O4) and is obtained as follows:To 300 mL of water in a 600-mL flask, preferably glass-stoppered, add 10 mL of HCl (sp gr 1.19) and1gofKI.Cooland add 10 mL of 0.1 N potassium permanganate (KMnO4)solution which has be
18、en standardized against Na2C2O4. Swirlgently, stopper, and let stand for 5 min. Titrate the liberatediodine with standard sodium thiosulfate (Na2S2O3) solutionuntil the color fades. Then add 10 mL of starch solution andcontinue the titration until the blue color is destroyed. Repeatthe titration, ex
19、cept substitute 10 mL of the KIO3for theKMnO4solution. Calculate the normality of the KIO3solutionas follows.5.8.1 Standardization Calculation for Theoretical SulfurTiter:B 5v13 NV2(1)where:B = normality of KIO3,V1= standard Na2S2O3solution, mL, required to titrate 10mL of KMnO4solution,N = normalit
20、y of standardized KMnO4solution, andV2= standard Na2S2O3solution, mL, required to titrate 10mL of KIO3solution.5.8.2 Standardization Against Known Pigment:C 5 A 3 S!/V 3 100! (2)where:A = sulfur in known pigment, %C = sulfide equivalent of the KIO3solution, g/mL,S = pigment, g, andV = KIO3solution r
21、equired to titrate known pigment, mL.5.9 Starch Indicator (for Sulfur Titration)To1Lofboiling water add a cold suspension of6gofstarch in 100 mLof water and boil vigorously for 5 min. Cool the solution, add6 g of zinc chloride (ZnCl2) dissolved in 50 mL of cold water,thoroughly mix, and set aside fo
22、r 24 h. Decant the clearsupernatant liquid into a suitable container, add3gofKI,andmix thoroughly.5.9.1 (Optional) Prepare an emulsion of6gofsolublestarch in 25 mL of water, add a solution of1gofsodiumhydroxide (NaOH) in 10 mL of water, and stir the solution untilit gels. Dilute to 1 L with water, a
23、dd3gofKI,andmixthoroughly.6. Preparation of Sample6.1 Separate and prepare the pigment for this determinationin accordance with Test Method D 2371.7. Procedure7.1 Place 0.5 to1gofthepigment in a flask with about 10g of “feathered” or mossy zinc and add 50 mL of water; inserta stopper carrying a sepa
24、ratory funnel and an exit tube. Run in50 mL of HCl (sp gr 1.19) from the funnel, having previouslyconnected the exit tube to two absorption flasks in series; thefirst flask containing 100 mL of alkaline lead nitrate solution,the second flask, 50 mL of the same solution as a safety device.After all o
25、f the acid has run into the evolution flask, heatslowly, finally boiling until the first appearance of steam in thefirst absorption flask.7.2 Disconnect, let the lead sulfide (PbS) settle, filter, andwash with cold water, then with hot water until neutral tolitmus paper and until the washings give n
26、o test for lead.Dissolve the PbS precipitate in hot HNO3(1+4) and determinethe lead as lead sulfate (PbSO4) in accordance with TestMethod D 215.7.3 For very rapid work, the evolved hydrogen sulfide (H2S)may be absorbed in an ammoniacal CdCl2or ZnSO4solution(5.3) contained in two flasks connected in
27、series, the contentsof the absorption flasks washed into a vessel with cold waterand diluted to about 1 L, acidified with HCl (sp gr 1.19), andtitrated with standard KIO3solution using starch indicator(5.9).8. Calculation8.1 Calculate the percent of sulfide sulfur, E, as follows:NOTE 1The percent of
28、 sulfide sulfur can be calculated from thepercent of total zinc and zinc soluble in acetic acid (2 to 3 %), assumingthe sulfide to be zinc sulfide (ZnS). See section on Total Zinc of TestMethod D 215.E 5 P 3 0.1054!/S 3 10C (3)where:P = PbSO4formed, g, andS = sample used, g.E 5 AV/S! 3 100 (4)where:
29、A = sulfide equivalent of the KIO3solution, g/mL,V = KIO3solution required for titration of specimen, mL,andS = sample used, g.9. Precision9.1 Data are not available to determine the precision of thistest method. There are no plans at present to obtain such data.This test method has been in use for
30、several years and isconsidered acceptable.10. Keywords10.1 sulfide; white pigmentD 2351 90 (2005)2ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determ
31、ination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or w
32、ithdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that
33、your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D 2351 90 (2005)3
