1、Designation: D 2010/D 2010M 98 (Reapproved 2004)Standard Test Methods forEvaluation of Total Sulfation Activity in the Atmosphere bythe Lead Dioxide Technique1This standard is issued under the fixed designation D 2010/D 2010M; the number immediately following the designation indicates theyear of ori
2、ginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of
3、Defense.1. Scope1.1 These test methods describe the evaluation of the totalsulfation activity in the atmosphere. Because of its oxidizingpower, lead dioxide (PbO2) converts not only sulfur dioxide(SO2), but other compounds, such as mercaptans and hydrogensulfide, into sulfate. It fixes sulfur trioxi
4、de and sulfuric acidmist present in the atmosphere (see Note 1).1.2 Test Method A describes the use of a PbO2candle, andTest Method B describes that of a PbO2sulfation plate.21.3 These test methods provide a weighted average effectiveSO2level for a 30-day interval.1.4 The results of these test metho
5、ds correlate approxi-mately with volumetric SO2concentrations, although thepresence of dew or condensed moisture tends to enhance thecapture of SO2onto the candle or plate.1.5 The values stated in SI units shall be regarded as thestandard. The values given in brackets are for information onlyand may
6、 be approximate.NOTE 1It has been shown that the rate constant of the chemicalreaction between SO2and PbO2is independent of the concentration ofSO2up to levels of 1000 ppm(v), if 15 % or less of the PbO2has beenreduced (1).315 % of the PbO2is equivalent to 11 to 12 mg of SO2/cm2per day.1.6 This stan
7、dard 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. For specificprecautionary s
8、tatements, see Section 8.2. Referenced Documents2.1 ASTM Standards:4D 516 Test Method for Sulfate Ion in WaterD 1193 Specification for Reagent WaterD 1356 Terminology Relating to Sampling and Analysis ofAtmospheresD 1357 Practice for Planning the Sampling of the AmbientAtmosphereG91 Practice for Mon
9、itoring Atmospheric SO2Using theSulfation Plate Technique3. Terminology3.1 DefinitionsFor definitions of terms used in these testmethods, refer to Terminology D 1356.3.2 Definitions of Terms Specific to This Standard:3.2.1 sulfationthe process by which sulfur-containingcompounds are oxidized by the
10、action of PbO2.3.2.2 sulfation activitythe capture rate of sulfur-containing compounds as they are oxidized by PbO2under theconditions of these test methods.4. Summary of Test Methods4.1 Test Method AInert cylinders are coated with PbO2paste and exposed to the atmosphere for an extended period oftim
11、e, usually one month. Sulfur oxides react chemically withthe paste, forming lead sulfate (PbSO4) (1-5).4.2 Test Method BSulfation plates consisting of a PbO2paste in an inverted dish are likewise exposed to the atmo-sphere (6).4.3 Test Methods A and BThe cylinders or plates arereturned to a laborato
12、ry after the sampling period; the paste isremoved and suspended in hot sodium carbonate (Na2CO3)solution to dissolve the PbSO4and convert the sulfate tosoluble sodium sulfate (Na2SO4). The Na2SO4solution is1These test methods are under the jurisdiction of ASTM Committee D22 onSampling and Analysis o
13、f Atmosphere and are the direct responsibility of Subcom-mittee D22.03 on Ambient Atmospheres and Source Emissions.Current edition approved October 1, 2004. Published December 2004. Originallyapproved in 1962. Last previous edition approved in 1998 as D 2010/D 2010M - 98.2Test Method B has been adap
14、ted from Test Method G91, which is under thejurisdiction of ASTM Committee G01 on Corrosion of Metals and is the directresponsibility of Subcommittee G01.04 on Atmospheric Corrosion.3The boldface numbers in parentheses refer to the list of references at the end ofthis standard.4For referenced ASTM s
15、tandards, visit 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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocke
16、n, PA 19428-2959, United States.separated from the PbO2slurry by filtration. The sulfate isdetermined by precipitation with barium chloride (BaCl2) (7).4.4 The chemistry of the process is illustrated, for the caseof SO2, in the following reactions:PbO21 SO2PbSO4PbSO41 N a2CO3Na2SO41 PbCO3Na2SO41 BaC
17、l2BaSO4 1 2 NaCl5. Significance and Use5.1 Sulfur oxide gases are produced during the combustionof materials containing sulfur. These gases are precursors ofatmospheric sulfuric acid, which has been shown to be injuri-ous to living creatures and plants, as well as some inanimatematerials such as met
18、als, limestone and sandstone buildingmaterials.5.2 Sulfur dioxide is moderately toxic and strongly phyto-toxic to many species. Permissible ambient levels of SO2havebeen established by law.5.3 When it is necessary to establish whether ambient airconcentrations of sulfuric acid precursors, such as su
19、lfuroxides, are present and to comply with legal criteria, manualand automatic monitoring systems specific for the individualsulfur species are used. Likely locations for monitoring sitesfor the estimation of concentrations and concentration trendsover long periods of time can be screened convenient
20、ly usingthe PbO2candles or sulfation plates.5.4 Atmospheric corrosion of metallic materials is a func-tion of many weather and atmospheric variables. The effect ofspecific corrodants, such as SO2, can accelerate the atmo-spheric corrosion of metals or structures significantly. ThePbO2candle and sulf
21、ation plate test methods provide simpletechniques to monitor SO2levels in the atmosphere indepen-dently to yield a weighted average result.5.5 The results of these test methods are useful for charac-terizing atmospheric corrosion test sites regarding the effectiveaverage concentrations of SO2in the
22、atmosphere at theselocations.5.6 These test methods are useful for determining microcli-matic seasonal and long-term variations in effective averageSO2concentrations.5.7 The results of these test methods may be used incorrelations of atmospheric corrosion rates with atmospheredata to determine the s
23、ensitivity of the corrosion rate to the SO2level.5.8 These test methods may also be used with other testmethods to characterize the atmosphere at sites at whichbuildings or other construction are planned in order to deter-mine the extent of protective measures required for thematerials of constructi
24、on.6. Apparatus6.1 Test Method A:6.1.1 Lead Dioxide CandleAn inert cylinder with a sur-face area of approximately 100 cm2, covered with a fabric andcoated with PbO2paste. See Appendix X1 for preparation ofthe candle.6.1.2 Sampling ApparatusThis may be a louvered enclo-sure, such as a cylinder or a r
25、ectangular box. If cylindrical, itshall be not less than 20-cm 8-in. high and 18-cm 7-in. indiameter; if rectangular, it shall be not less than 20 by 20 by 20cm 8 by 8 by 8 in. Position the louvers at an angle of p/4(45) to provide maximum protection from the rain. Constructthe enclosure of an inert
26、 material, such as plastic or wood. Donot coat the enclosure with a lead based paint. The samplingapparatus shall have provisions to hold the PbO2candle in avertical position.6.2 Test Method B:6.2.1 Sulfation PlateA polystyrene or polycarbonate cul-ture (petri) dish, 50 or 60 mm in diameter, contain
27、ing a filterpaper disc, coated with PbO2paste. See X1.2 for preparation ofthe sulfation plate.6.2.2 Bracket, to hold the plates securely in an invertedposition so that the PbO2mixture faces downward. The bracketdesign shall include a retaining clip or other provision to holdthe plate in the event of
28、 strong winds. The retainer clip may bemade from stainless steel, spring bronze, hard aluminum alloy(3003H19), or other alloys with sufficient strength and atmo-spheric corrosion resistance. A typical bracket design is shownin Fig. 1.7. Reagents and Materials7.1 Purity of ReagentsReagent grade chemi
29、cals shall beused in all tests.All reagents shall conform to the specificationsof the Committee on Analytical Reagents of the AmericanChemical Society, except where such reagents are not avail-able.57.2 Purity of WaterReferences to water shall be under-stood to mean reagent water as defined by Type
30、II of Specifi-cation D 1193.7.3 AcetoneReagent grade.7.4 Barium Chloride Solution (50 g/L)Dissolve 59 g ofbarium chloride dihydrate (BaCl23 2H2O) in water and diluteto1L.7.5 Ethyl Alcohol (95 %).7.6 Gum Tragacanth, powdered.7.7 Hydrochloric Acid (sp gr 1.19)Concentrated hydro-chloric acid (HCl).7.8
31、Hydrochloric Acid (2 N)Dilute 171 mL of concen-trated HCl to 1 L.7.9 Hydrochloric Acid (0.05 N)Dilute 25 mL of 2 N HClto1L.7.10 Lead Dioxide (Powdered)PbO2of the highest purity.7.11 Sodium Carbonate Solution (83.3 g/L)Dissolve 83.3g of anhydrous sodium carbonate (Na2CO3) in water and diluteto1L.7.12
32、 Methyl Orange Indicator (0.1 %)Dissolve 100 mg inwater and dilute to 100 mL.5Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for Laborat
33、oryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D 2010/D 2010M 98 (2004)28. Precautions8.1 Safety PrecautionsSince lead is a toxic material,prepare and analyze the PbO2candles and sulfatio
34、n platesunder a fume hood, or with a respirator approved for use withtoxic dusts.8.2 PbO2, which is a strong oxidizing agent, can permeateand contaminate any laboratory area, making it impossible foruse in conducting analysis of environmental samples for lead.Therefore, use a dedicated room that is
35、well ventilated to theoutside for the PbO2candle or sulfation plate work.9. Sampling9.1 Refer to Practice D 1357 for guidance in planningsampling programs.9.2 When these test methods are used for estimating the SO2concentration over a designated area, select sampling stationsat random on a uniform n
36、etwork grid over the area to bestudied. The density of the sampling stations shall not be lessthan 1/km22/mile2.9.3 Location of Sampling DeviceLocate the box orbracket in a manner that will ensure protection from tamperingand security from falling.The height from ground level shall bethe same at all
37、 stations. The minimum height above thesupporting surface shall be 1 m 3 ft. The sulfation plate shallbe horizontal and placed so that it is not protected from normalwinds and air currents.9.4 The sampling period may be 1 month or long enough toprovide a convenient minimum of total sulfate for analy
38、sis.The work of Keagy (5), which is used as the criterion for thesampling procedure for candles, shows a range from 5 to 2000mg of barium sulfate (BaSO4) per candle. The samplingfrequency shall be uniform and determined by the requirementsFIG. 1 Sulfation Plate HolderD 2010/D 2010M 98 (2004)3of the
39、survey. Monthly, bimonthly, and seasonal samplingperiods have been shown to provide consistent and reliabledata (5).10. Analytical Procedure10.1 Return the candles or plates to containers that can besealed from contamination at the end of the sampling period.10.2 Test Method A, Treatment of CandlesM
40、easure thesurface area of the candle. Separate the impregnated clothsurface from the cylinder, using a spatula or knife point, ifnecessary. The fabric may be cut into smaller pieces. Transferthe PbO2-covered fabric to a 250-mL beaker containing 60 mLof 83.3-g/L solution of Na2CO3(7.11). Soak the imm
41、ersedpieces for 3 h, with occasional stirring. Cover the beakers, andsimmer the mixtures gently on a water bath plate for 30 min,taking care to minimize water evaporation in order to maintainan approximately constant volume. Filter the beaker contentsthrough a fast filter paper, with appropriate was
42、hings, andadjust the filtrate with 2 N HCl (7.8) to a pH range of 3.0 to 4.0,using methyl orange as the indicator (7.12). Exercise care toprevent any loss of sample by foaming, particularly when thepoint of neutralization is approached.10.3 Test Method BRemove the contents of the sulfationplate to a
43、 250-mL beaker, and add 12 mL of 83.3 g/L Na2CO3solution (7.11). Cover the beaker, and proceed as described in10.2.10.4 Determination of Sulfate as Barium SulfateDetermine the sulfate ion in accordance with the gravimetrictest method (Test Method A) in Test Method D 516. The rapidaddition of a boili
44、ng solution of BaCl2(7.4) to a gently boilingsolution of the sulfate in 0.05 N HCl (7.9) will yield a granularand easily filterable BaSO4precipitate.10.5 Determine the sulfate in the unexposed (blank) candleor plate, and subtract from the exposed sampler values.11. Calculation11.1 Calculate the tota
45、l sulfation activity, expressed as SO2equivalent, as follows:M 5W 3 274.5A 3 t(1)where:M = total sulfation activity, in mg SO2/cm23 day,W = mass of BaSO4, in g, corrected for blank,274.5 = ratio of the molecular weights of SO2andBaSO4, 3 1000 to convert g to mg,A = area of candle or plate, in cm2, a
46、ndt = time of exposure, in days.12. Precision and Bias12.1 Test Method A (8):12.1.1 The interlaboratory study of Project Threshold pro-vided the following conclusions regarding the precision of TestMethod A.12.1.1.1 The standard deviation, Sb, for the reproducibilityof total sulfation activity measu
47、rements by different laborato-ries ranging from 0.00178 to 0.01371 mg/cm23 day may beexpressed by the following equation:Sb5 0.0136 M(2)where:Sband M = mg/cm23 day.12.1.1.2 The standard deviation, Sw, for replicate measure-ments of total sulfation activity ranging from 0.00178 to0.01371 mg/cm23 day
48、by the same laboratory (repeatability)may be expressed by the following equation:Sw5 0.00504 M(3)where:Swand M = mg/cm23 day.12.1.2 The average results of the analysis of spiked samples(8) indicates that the determination of sulfate by Test MethodD 516 can be performed with a recovery of 98 %.12.1.2
49、.1 The standard deviation of the percent of sulfatespike recovery of the sulfate analysis step is 10 % for between-laboratory measurements and 21 % for within-laboratory mea-surements.12.2 Test Method B (9):12.2.1 The standard deviation of replicate plates run underthe same exposure conditions for a single laboratory has beenfound to be related to the mean sulfation level by the equationgiven below:s50.0790 mavg(4)where:s = standard deviation in mg SO2/m23 day, andmavg= mean net SO2capture rate in mg SO2/m23 daybased on 10 runs with six or m
