1、Designation: E 832 81 (Reapproved 2008)Standard Specification forLaboratory Filter Papers1This standard is issued under the fixed designation E 832; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numbe
2、r 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 This specification covers two types of filter paper for use
3、in chemical analysis and provides procedures for the completeevaluation of the filter papers.2. Referenced Documents2.1 ASTM Standards:2D 774/D 774M Test Method for Bursting Strength of Paper2.2 TAPPI Standards:3T413 Ash in PaperT429 Alpha-Cellulose in PaperT509 Hydrogen Ion Concentration (pH) of Pa
4、per ExtractsCold Extraction Method3. Types and Classes3.1 The types and classes of filter paper are as follows:3.1.1 Type ITo be used for qualitative analysis (low ashcontent):3.1.1.1 Class AA, for very coarse and gelatinous precipi-tates, very fast flow rate.3.1.1.2 Class A, for coarse and gelatino
5、us precipitates, fastflow rate.3.1.1.3 Class B, for medium-size precipitates, medium flowrate.3.1.1.4 Class C, for fine precipitates, slow flow rate.3.1.1.5 Class D, hardened to facilitate scraping, for fineprecipitates, slow flow rate.3.1.2 Type IIto be used for quantitative analysis (ashlesspapers
6、):3.1.2.1 Class E, for coarse and gelatinous precipitates, fastflow rate.3.1.2.2 Class F, for medium-size precipitates, medium flowrate.3.1.2.3 Class G, for fine precipitates, slow flow rate.4. Manufacture4.1 The papers shall be made from such materials and bysuch methods as to ensure compliance wit
7、h the requirements ofSection 10, and shall be clean and free of imperfections thatwould affect their performance.4.2 The papers shall be converted into circles, sheets, or anyrequired sizes.5. General Requirements General Requirements5.1 All classes of filter paper shall comply with the require-ment
8、s given in Table 1 and Table 2 and Section 11.5.2 The ash content of the Type II circles shall not exceed0.01 %.5.3 Class D filter papers shall have a surface hard enough topermit scraping collected precipitates off the sheet.6. Sampling6.1 If testing is required, the sample of each class shall bere
9、presentative of the shipment, and specimens shall be taken atrandom from at least 3 % of the total packages.7. Retests7.1 If the results of the tests indicate noncompliance withthe requirements of Table 1 and Table 2, or other factorsdescribed within this specification, take another representativesa
10、mple of the shipment, selecting the specimens from differentpackages than those from which the first sample was taken.7.2 Then test the second sample for compliance with thisspecification.7.3 If the results of the retests indicate noncompliance withthis specification, immediately consult the manufac
11、turer forassistance in rectifying the problem.8. Packaging and Marking8.1 Flat circles of filter paper shall be packaged in units of100 circles of the same diameter. Prefolded or fluted circlesshall be packaged according to trade custom.1This specification is under the jurisdiction of ASTM Commmitte
12、e E41 onLaboratory Apparatus and is the direct responsibility of Subcommittee E41.01 onApparatus.Current edition approved Nov. 1, 2008. Published January 2009. Originallyapproved in 1950. Last previous edition approved in 2003 as D 1100 81 (2003).2For referenced ASTM standards, visit the ASTM websit
13、e, 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.3Available from Technical Association of the Pulp and Paper Industry (TAPPI),15 Technology Parkway South, Norcross
14、, GA 30092, http:/www.tappi.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.8.2 Each unit or package shall be marked with the manu-facturers name, size of circles, or catalog and lot number.9. Test Methods9.1 The most important t
15、ests to be performed are:9.1.1 pH ValueDetermine in accordance with TAPPIMethod T 509.9.1.2 Alpha-CelluloseDetermine in accordance withTAPPI Method T 429. This test may or may not be used for lotto lot determination.9.1.3 Ash ContentDetermine in accordance with Section10.1 or TAPPI Method T 413, app
16、licable for Type II papers.9.1.4 Retention of precipitates, simple method to determineretention ability of filter paper as determined in accordancewith 10.2.9.1.5 Water Flow RateDetermine the flow rates of filterpaper in accordance with 10.3 or the Herzberg method (mea-surement of time for the filtr
17、ation of 100 mL of prefiltereddistilled water with a filter surface of 10 cm2at a constantpressure of 50 mm water column).9.1.6 Wet Bursting StrengthDetermine in accordance with10.4.10. Test Methods10.1 Ash Content:10.1.1 Apparatus:10.1.1.1 Crucibles, 20-mL platinum, with tightly fittingcovers. One
18、for each sample.10.1.1.2 Heat SourceAn electric muffle furnace with anoperating temperature of approximately 925C is recom-mended, but a gas burner yielding a similar temperature issufficient.10.1.1.3 Test specimens, having a mass of at least 6 g,representative of the sample obtained as prescribed i
19、n Section6, and cut in the shape of whole circles of the same diameter orsmall strips measured for area.10.1.2 Procedure:10.1.2.1 Heat the crucibles with their respective covers toapproximately 925C. Cool in a desiccator and weigh to thenearest 0.1 mg. Add the specimen into crucible.10.1.2.2 Heat th
20、e covered crucible plus test specimen gradu-ally until smoking ceases, remove cover, then continue heatinguntil the maximum temperature of 925C is reached andmaintain for 2 h. Replace the cover and cool the coveredcrucible in a desiccator until temperature equilibrium with thesurrounding air is reac
21、hed. Weigh the crucible and contents tothe nearest 0.1 mg. Ignition is considered to be complete whenthe weight of the covered crucible and ash does not change bymore than 0.2 mg after reheating at 925C for 30 min.10.1.2.3 BlankCarry a tare crucible with cover through alloperations in exactly the sa
22、me manner as the crucibles con-taining specimens, as a check on possible loss of mass of thecrucibles themselves.10.1.2.4 Test at least two specimens per sample.10.1.3 Calculation and ReportCalculate and report theash, corrected for the results of the blank test, to two significantfigures. Determine
23、 the weight percentage of the paper dried at105C.10.1.4 PrecisionDuplicate determinations shall agree asfollows:Ash, %Rounded toNearestReproducibility, %0.025 0.001 0.0030.025 to 0.01 0.005 0.010.1 0.01 0.0210.2 Retention of Precipitates:10.2.1 Apparatus:10.2.1.1 Glass Funnels, 60, having stems abou
24、t 6 in. long.10.2.2 Reagents:10.2.2.1 Alcohol (95 %)Ethanol or formula No. 30.10.2.2.2 Ammonium HydroxideAdd one part, by volume,of cp ammonium hydroxide (NH4OH) to one part by volumeof distilled water.10.2.2.3 Barium Chloride Solution (50 g/L)Dissolve 58.5g of cp barium chloride (BaCl22H2O) in dist
25、illed water anddilute to 1 L.10.2.2.4 Ferric Chloride SolutionDissolve 10 parts byweight of cp ferric chloride (FeCl36H2O) in 100 mL ofdistilled water.10.2.2.5 Hydrochloric Acid (sp gr 1.19).10.2.2.6 Lead Acetate, cp anhydrous.10.2.2.7 Potassium Sulfate (K2SO4) cp.10.2.2.8 Sulfuric Acid (6 N).10.2.3
26、 Procedure:10.2.3.1 Determine retention of precipitates by examiningthe filtrate from freshly prepared suspensions of ferric hydrox-ide, lead sulfate, or barium sulfate, after filtering throughspecimens of the filter paper under test. To examine the filtrate,swirl it in the flask to collect any prec
27、ipitate present in thecenter of the bottom of the flask, and then view the filtrate fromabove against a black background. In this manner 0.3 mg orless can be detected. Complete retention of fine precipitates isindicated by the absence of visible barium sulfate (BaSO4)inthe filtrate.10.2.3.2 For Rete
28、ntion of Ferric HydroxideAdd a slightexcess of dilute NH4OH to the cold (room temperature) FeCl3solution and shake, then promptly filter the suspension throughone specimen of the filter paper under test, using a 60 funnel,TABLE 1 General RequirementsProperty Requirementalphacellulose content, min, %
29、 95pH value 5.0 to 8.0TABLE 2 Wet Bursting StrengthClassWater Flow Rate and Retention of PrecipitatesWet BurstingStength min,aug pointsMaximumWater FlowRate,aug, sRetention of Pre-cipitatesFiltrateClear from:AA 3.0 10 ferric hydroxideA 3.0 20 ferric hydroxideB 3.5 40 lead sulfateC 4.0 150 barium sul
30、fateD 45.0 300 barium sulfateE 3.0 20 ferric hydroxideF 3.5 40 lead sulfateG 4.0 150 barium sulfateE 832 81 (2008)2into an Erlenmeyer flask, examine the filtrate as directed in10.2.3.1. Test at least four specimens per sample.10.2.3.3 For Retention of Lead SulfateDissolve 10 g oflead acetate in 100
31、mL of distilled water; filter through a filterpaper capable of retaining BaSO4. Then add 40 mL of 6 N H2SO4and 80 mL of alcohol. After the mixture has stood for 4 h,filter the suspension through one specimen of the filter paperunder test, in a 60 long-stemmed glass funnel into anErlenmeyer flask. Wa
32、sh the precipitate and the precipitationflask with dilute H2SO4(5 mL of concentrated acid to 100 mLof distilled water). Then wash the precipitate on the paper withalcohol. Examine the filtrate as directed in 10.2.3.1. Test atleast four specimens per sample.10.2.3.4 For Retention of Barium SulfateDis
33、solve 0.55 gof K2SO4in 275 mL of water and add 1.0 mL of HCl. Thisvolume of solution contains the equivalent of about 0.1 g ofsulfur. Heat the solution to the boiling point and, when at thattemperature, add slowly and with continuous stirring 25 mL ofBaCl2(50 g/L). Let the mixture stand without agit
34、ation for from2to6hatatemperature between 70 and 100C.NOTE 1It is very important to have the specified acid concentrationand to keep the solution boiling during the precipitation.10.2.3.5 Fold four of the filter papers in the usual way forfiltration and place them in separate funnels. Stir the preci
35、pitatesuspension until the BaSO4is evenly distributed throughout theliquid. Then filter about 50 mL through each cone of paper,collecting the filtrates in 250-mL Erlenmeyer flasks. Examinethe filtrate in the flasks as directed in 10.2.3.1.10.3 Water Flow Rate:10.3.1 Apparatus:10.3.1.1 Glass Funnel,
36、60.10.3.1.2 Buret, 50-mL.10.3.2 Procedure:10.3.2.1 Use distilled water that has been prefiltered throughthe test paper or through an 0.45-m membrane. Prepare threeof four times as much water as is necessary to fill the foldedpaper cones to be tested.10.3.2.2 Carefully fold a circle of the filter pap
37、er in theusual way, to form a 60 cone, having a diameter of 11 cm.Place it in a 60 glass funnel and fill it with the prefilteredwater. Press down the folds to expel all air pockets and to makethe three plies smooth and in good contact. Allow about threefourths of the water to filter, then pour off t
38、he excess, saving thewater to wet other test specimens. Remove the wet paper conefrom the funnel and suspend it freely over the buret bysupporting the cone in a wire loop of such diameter that itsupports the cone at about two thirds of the distance from theapex to the rim.10.3.2.3 Using prefiltered
39、water having a temperature of 236 2C, pour into the cone, all at once, a known volume that isapproximately two thirds of the volume of the cone. When onefifth of the water has filtered through into the buret, start a stopwatch. When half the remaining volume has filtered through,stop the stop watch
40、and record the time in seconds. Test at least10 circles, using the same water over and over and adding itfrom the prepared supply as found necessary.NOTE 2Asuitable volume of water initially poured in, for filter circles11 cm in diameter, is 25 mL.10.3.2.4 The time required to filter half the volume
41、 of waterremaining in the conical filter is substantially the same for anygiven paper, irrespective of the size of the test specimen.10.3.3 ReportReport the filtration time in seconds andstate the diameter in centimetres of the filter paper used for thetest.10.4 Wet Bursting Strength:10.4.1 Procedur
42、e Clip together a pack of five squares (64mm by 64 mm) of the filter paper, and immerse the pack indistilled water at 23 6 2C for 5 min. Remove the pack fromthe water, and allow it to drain while suspended for 10 s. Thenimmediately measure the bursting strength of the wet pack ina Mullen tester that
43、 conforms with the requirements of MethodD 774, test for bursting strength of paper. Test at least five andpreferably ten packs.10.4.2 ReportThe report shall state the number of testsmade, and the average, maximum, and minimum test results.11. Visual Inspection11.1 Circles from each package of the s
44、ample shall beinspected visually for compliance with Section 3.12. Ascertaining Compliance with Specification12.1 The data generated through performance of the testmethods outlined in Section 9 shall be compared with Table 1and Table 2 to determine compliance.13. Keywords13.1 filter; laboratory; pap
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46、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 withdrawn. Your comments are invited either for revision of this standard or for additional stan
47、dardsand 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 your comments have not received a fair hearing you shouldmake your views known to the ASTM Comm
48、ittee 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).E 832 81 (2008)3
