1、Designation: D 4646 03Standard Test Method for24-h Batch-Type Measurement of Contaminant Sorption bySoils and Sediments1This standard is issued under the fixed designation D 4646; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、 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 describes a procedure for determiningthe sorption affinity of waste solutes by unconsolidat
3、ed geo-logic material in aqueous suspension. The waste solute may bederived from a variety of sources such as wells, underdrainsystems, or laboratory solutions such as those produced bywaste extraction tests like the Test Method D 3987 shakeextraction method.1.2 This test method is applicable in scr
4、eening and provid-ing relative rankings of a large number of geomedia samplesfor their sorption affinity in aqueous leachate/geomedia sus-pensions. This test method may not exactly simulate sorptioncharacteristics that would occur in unperturbed geologic set-tings.1.3 While this procedure may be app
5、licable to both organicand inorganic constituents, care must be taken with respect tothe stability of the particular constituents and their possiblelosses from solution by such processes as degradation bymicrobes, light, or hydrolysis. This test method should not beused for volatile chemical constit
6、uents (see 6.1).1.4 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
7、.2. Referenced Documents2.1 ASTM Standards:2D 1129 Terminology Relating to WaterD 1193 Specification for Reagent WaterD 2216 Test Method for Laboratory Determination of Water(Moisture) Content of Soil and RockD 3987 Test Method for Shake Extraction of Solid Wastewith WaterD 4319 Test Method for Dist
8、ribution Ratios by the Short-Term Batch Method3. Terminology3.1 DefinitionsFor definition of terms used in this testmethod refer to Terminology D 1129.3.1.1 solutechemical species (for example, ion, molecule,etc.) in solution.3.1.2 sorbatechemical species sorbed by a sorbent.3.1.3 sorbenta substance
9、 that sorbs the solute from solu-tion (for example, soil, sediment, till, etc.).3.1.4 sorptiondepletion of an amount of solute initiallypresent in solution by a sorbent.3.1.5 sorption affnitythe relative degree of sorption thatoccurs by a geomedia.3.1.6 unconsolidated geologic material (geomedia)alo
10、osely aggregated solid natural material of geologic origin (forexample, soil, sediment, till, etc.).3.2 Definitions of Terms Specific to This Standard:3.2.1 distribution coeffcient, Kdthe ratio of the concen-tration of solute sorbed on the soil or other geomedia dividedby its concentration in soluti
11、on. A 24-h Kdis the analogousratio evaluated after 24 h of contact of the solute with thegeomedia.3.2.1.1 DiscussionThe dimensions of Kdreduce to unitsof volume per mass. It is convenient to express Kdin units ofmillilitres (or cubic centimetres) of solution per gram ofgeomedia. Dissimilar Kdvalues
12、may be obtained if differentinitial solute concentrations are used, depending on the sorp-tion behavior of the solute and the properties of the geomedia(that is, nonlinear sorption curve). This concentration depen-dency may be absent where the solute concentrations aresufficiently low or the charact
13、eristics of the particular solute-sorbent combination yield Kdvalues that are independent of theconcentration of solute (that is, linear sorption curve).4. Summary of Test Method4.1 Distilled water, natural water, waste leachate, or otheraqueous solution containing a known concentration of a solutei
14、s mixed with a known amount of unconsolidated geologic1This test method is under the jurisdiction of ASTM Committee D34 on WasteManagement and is the direct responsibility of Subcommittee D34.01.06 onAnalytical Methods.Current edition approved Nov. 1, 2003. Published January 2004. Originallypublishe
15、d as ES 10 85. Last previous edition D 464687.2For referenced ASTM standards, 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
16、 International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.material (geomedia) for 24 h. After 24 h, equilibrium betweenthe solid and solution phase is presumed to occur. Theconcentration of solute remaining in solution is measured andthe amount of solute ads
17、orbed is calculated. Given that themass of solid phase is known, the distribution coefficient forthe specified experimental conditions can then be calculated.5. Significance and Use5.1 This test method is meant to allow for a rapid (24 h)index of a geomedias sorption affinity for given chemicals orl
18、eachate constituents. A large number of samples may be runusing this test method to determine a comparative ranking ofthose samples, based upon the amount of solute sorbed by thegeomedia, or by various geomedia or leachate constituents.The 24-h time is used to make the test convenient and also tomin
19、imize microbial degradation which may be a problem inlonger-timed procedures. While Kdvalues are directly appli-cable for screening and comparative ranking purposes, theiruse in predictive field applications generally requires theassumption that Kdbe a fixed value.5.2 While this test method may be u
20、seful in determining24-h Kdvalues for nonvolatile organic constituents, interlabo-ratory testing has been carried out only for the nonvolatileinorganic species, arsenic and cadmium. However, the proce-dure has been tested for single laboratory precision withpolychlorinated biphenyls (PCBs) and is be
21、lieved to be usefulfor all stable and nonvolatile inorganic, and organic constitu-ents. This test method is not considered appropriate for volatileconstituents.5.3 The 24-h time limit may be sufficient to reach asteady-state Kd. However, to report this determination as asteady-state Kd, this test me
22、thod should be conducted forintermediate times (for example, 12, 18 and 22 h) to ensure thatthe soluble concentrations in the solution have reached a steadystate by 24 h. Refer to Test Method D 4319 for an alternateprocedure of longer duration.6. Interferences6.1 When dealing with solutes of unknown
23、 stability either incontact with the geomedia or when used as blanks, care mustbe taken to determine if volatilization, hydrolysis, photodeg-radation, microbial degradation, oxidation-reduction (for ex-ample, Cr3+to Cr6+) or other physicochemical processes areoperating at a significant rate within t
24、he time frame of theprocedure. The stability and hence loss from solution mayaffect the outcome of this procedure if the aforementionedreactions are significant. The compatibility of the method andthe solute of interest may be assessed by determining thedifferences between the initial solute concent
25、ration (see 9.8)and the final blank concentration of the solute (see 9.15). If thisdifference is greater than the expected precision of the method(10 %), then the Kdvalue generated may be unreliable andmust be carefully evaluated.7. Apparatus7.1 Agitation EquipmentThe agitation equipment to beused i
26、s the rotary solid waste extractor3specified in TestMethod D 3987.7.2 Phase Separation EquipmentA filtration apparatusmade of materials compatible with the solutions being filteredand equipped with a 0.45-m pore size membrane filter, or aconstant temperature centrifuge capable of separating particle
27、swith diameters greater than 0.1 m (see Section 9). If organiccompounds are being measured, the filtration apparatus, cen-trifuge tubes etc., should be compatible with the compoundsbeing measured (that is, glass or stainless steel). Sorption ofsolute onto the filtration membrane may be significant f
28、or somesolutes, and must be evaluated by the use of blanks through allsteps of the procedure.7.3 ContainersRound, wide-mouth bottles compatiblewith the rotary extractor (Test Method D 3987) and of compo-sition suitable to the nature of the solute(s) under investigationand the analysis to be performe
29、d will be used. For nonvolatileinorganic constituents, high-density, linear polyethylene bottlesshould be used with the size of the bottle dictated by samplesize, and the need for the solution to occupy 70 to 80 % of thecontainer volume (that is, 125 mL, 250 mL, or 2-L bottles forsample sizes of 5,
30、10, or 70 g respectively). For nonvolatileorganic constituents, TFE-fluorocarbon, glass bottles, or stain-less steel containers with water-tight closures made of chemi-cally inert materials should be used with size requirementsbeing the same as for nonvolatile inorganics. Containers shouldbe cleaned
31、 in a manner consistent with the analyses to beperformed. Samples of the solutions to be analyzed should bestored in similar chemically compatible bottles.7.4 Balance, having a minimum capacity of 70 g and asensitivity of 60.005 g shall be used.8. Reagents8.1 Purity of ReagentsReagent grade chemical
32、s shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the AmericanChemical Society, where such specifications are available.4Other grades may be used, provided it is first ascertained thatthe reagent is of sufficiently high pu
33、rity to permit its usewithout lessening the accuracy of the determination.8.2 Purity of Water Unless otherwise indicated, refer-ences to water shall be understood to mean Type IV reagentwater of Specification D 1193.3Diamondstone, B. T., Burke, R. W., and Garner, E. L., “Improved LeachMeasurements o
34、n Solid Wastes,” ASTM Standardization News, June 1982, pp.2833.4Reagent 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 LaboratoryChemicals,
35、BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D46460329. Procedure9.1 Geomedia samples are spread out on a flat surface, nomore than 2 to 3 cm deep, and allowed to air dry for 7 days oruntil constant
36、weight (a change that is less than 5 %/24-hperiod) is achieved (do not oven dry).9.2 After the sample has air dried, it is passed through a2-mm screen sieve. Large aggregates are to be crushed, withoutgrinding, using a clean mortar and a rubber-tipped pestle.9.3 Mix the sieved material until the sam
37、ple is homoge-neous. Use a riffle splitter, or other unbiased splitting proce-dure, to obtain subsamples of appropriate size.9.4 Remove subsamples and determine the moisture contentof the air-dried sample (refer to Test Method D 2216).9.5 Determine the mass of geomedia sample, corrected formoisture
38、content:Determination of air-dried soil mass equivalent to the desiredmass of oven-dried soil:A 5 Ms1 1 M/100! (1)where:A = air dry soil massMs= mass of oven-dried soil desired, andM = moisture, %.9.6 Place between 5 and 70 g (oven-dried basis) of theweighed air-dried sample into the appropriate con
39、tainer. Thesamples should be weighed to a minimum of three significantfigures.9.7 Add to the container an amount of solute solutionnecessary to yield a 1:20 soil-to-solution ratio. This is deter-mined on the oven-dried basis:Determination of solution volume needed per sample for asoil-to-solution ra
40、tio of 1:20:V 5 Ms3 20!/r (2)where:r = density of solution, g/cm3,V = volume of solution per sample, cm3, andMs= mass of soil to be used, g, (oven-dried basis).9.8 Retain a separate, appropriately preserved aliquot of theinitial solute solution for analysis.9.9 Close the container and place it on th
41、e rotary extractor(Test Method D 3987).9.10 Agitate continuously for 24 6 0.5hat296 2 r/min atroom temperature (22 6 5C).9.11 Open the container. Note the temperature of the solu-tion and any changes in the sample or solution (that is, color,odor, etc.).9.12 Separate the solution phase from the majo
42、rity of thesolid phase by decantation.9.13 Filter the solution phase through a 0.45-m pore sizemembrane filter (see 7.2), or centrifuge a subsample at thepredetermined rate of rotation and time for the centrifugationequipment employed at constant temperature (the temperaturerecorded after 24 h):t 5
43、9/2Shv2rp2rp2r!Dln Rb/Rt! (3)where:v2=4p2r/min!260= angular velocity,rp= particle radius, cm,h = viscosity of water, 8.95 3 103g/s-cm at 25C,rp= particle density,r = density of solution,r/min = revolutions per minute,Rt= distance from center of centrifuge rotor to top ofsolution in centrifuge tube,
44、cm,Rb= distance from center of centrifuge rotor to bottomof centrifuge tube, cm, andt = time, min.To remove particles 0.1-m radius and 2.65-g/cm3densityfrom solution:t 5S3.71 3 108r/min!2 Dln Rb/Rt! (4)Note that if filtration is used, the affinity of the filtrationmembrane for the solute must be eva
45、luated. Failure to do somay lead to erroneous results.9.14 After a clear solution has been obtained, place analiquot in an appropriate container (see 7.3), and analyze orstore in a refrigerator at 4 6 2C until analyzed.9.15 Each geomedia sample is to be subjected to theprocedure in three or more rep
46、licates. The number of blanks(that is, solute solution without geomedia) carried through allsteps of the procedure should be a minimum of 5 % of the totalnumber of geomedia samples, but not less than three.10. Calculation10.1 Calculate the distribution as follows:Kd5A 2 B!VMs!B(5)where:A = initial c
47、oncentration of the solute defined as the meanconcentration of the blanks, g/mL,B = final concentration of the solute after 24 h in contactwith the geomedia, g/mL,V = volume of solution used, mL,Ms= mass of soil expressed on an oven-dried basis, g, andKd= distribution coefficient, mL/g.11. Report11.
48、1 The Kdvalue must be clearly marked as nonequilib-rium 24-h distribution coefficient.11.2 Both the initial solute concentration ( A in 10.1) and thefinal solute concentration (B in 10.1) must be reported.11.3 The initial and final solute concentration for each blank(solution without geomedia) must
49、be reported.11.4 The mass of the sorbent (Msin 10.1), volume ofsolution (V in 10.1), and the room temperature at which therotary extractor was operated must be reported.11.5 Report the temperature of the solution and any changesnoted in 9.11.D464603311.6 Note and report negative Kdvalues when and if theyoccur. Negative Kdvalues may occur if the geomedia containsthe test solute prior to the application of the method.11.7 It is suggested that the pH of the sorbent-solute mixturebe determined prior to separating the sorbent from the liquidand rep
