1、Designation: D 4646 03 (Reapproved 2008)Standard 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 cas
2、e of revision, 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.1. Scope1.1 This test method describes a procedure for determiningthe sorption affinity of waste solute
3、s by unconsolidated 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
4、applicable in screening 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 pro
5、cedure may be applicable 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
6、 chemical constituents (see 6.1).1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user o
7、f this standard to 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 1129 Terminology Relating to WaterD 1193 Specification for Reagent WaterD 2216 Test Methods for Laboratory Determ
8、ination of Wa-ter (Moisture) Content of Soil and Rock by MassD 3987 Test Method for Shake Extraction of Solid Wastewith WaterD 4319 Test Method for Distribution Ratios by the Short-Term Batch Method33. Terminology3.1 DefinitionsFor definition of terms used in this testmethod refer to Terminology D 1
9、129.3.1.1 solutechemical species (for example, ion, molecule,etc.) in solution.3.1.2 sorbatechemical species sorbed by a sorbent.3.1.3 sorbenta substance that sorbs the solute from solu-tion (for example, soil, sediment, till, etc.).3.1.4 sorptiondepletion of an amount of solute initiallypresent in
10、solution by a sorbent.3.1.5 sorption affnitythe relative degree of sorption thatoccurs by a geomedia.3.1.6 unconsolidated geologic material (geomedia)aloosely aggregated solid natural material of geologic origin (forexample, soil, sediment, till, etc.).3.2 Definitions of Terms Specific to This Stand
11、ard:3.2.1 distribution coeffcient, Kdthe ratio of the concen-tration of solute sorbed on the soil or other geomedia dividedby its concentration in solution. 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 u
12、nitsof volume per mass. It is convenient to express Kdin units ofmillilitres (or cubic centimetres) of solution per gram ofgeomedia. Dissimilar Kdvalues may be obtained if differentinitial solute concentrations are used, depending on the sorp-tion behavior of the solute and the properties of the geo
13、media(that is, nonlinear sorption curve). This concentration depen-dency may be absent where the solute concentrations aresufficiently low or the characteristics of the particular solute-sorbent combination yield Kdvalues that are independent of theconcentration of solute (that is, linear sorption c
14、urve).1This 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 Oct. 1, 2008. Published December 2008. Originallyapproved as ES 10 85. Last previous edition approved in
15、 2003 as D 464603.2For 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.3Withdrawn. The last approved version of th
16、is historical standard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4. Summary of Test Method4.1 Distilled water, natural water, waste leachate, or otheraqueous solution containing a known concentratio
17、n of a soluteis mixed with a known amount of unconsolidated geologicmaterial (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 adsorbed is calculated. Given that
18、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 orleachate constituents. A large nu
19、mber 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 tominimize microbial degradation whic
20、h 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 useful in determining24-h Kdvalue
21、s 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 believed to be usefulfor all stabl
22、e 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 method should be conducted forinte
23、rmediate 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 stability either incontact with
24、 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 the time frame of theprocedure. T
25、he 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 concentration (see 9.8)and the final bl
26、ank 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 is the rotary solid waste extract
27、or4specified 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 particleswith diameters greater than 0.1
28、 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 for somesolutes, and must be eval
29、uated 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 performed will be used. For nonvolatilei
30、norganic 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, 10, or 70 g respectively). For n
31、onvolatileorganic 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 in a manner consistent with the
32、 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 chemicals shall beused in all tests. Unl
33、ess otherwise indicated, it is intended thatall reagents shall conform to the specifications of theAmericanChemical Society, where such specifications are available.5Other grades may be used, provided it is first ascertained thatthe reagent is of sufficiently high purity to permit its usewithout les
34、sening 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 1193.9. Procedure9.1 Geomedia samples are spread out on a flat surface, nomore than 2 to 3 cm deep, and allowed to air dry
35、 for 7 days or4Diamondstone, B. T., Burke, R. W., and Garner, E. L., “Improved LeachMeasurements on Solid Wastes,” ASTM Standardization News, June 1982, pp.2833.5Reagent Chemicals, American Chemical Society Specifications , AmericanChemical Society, Washington, DC. For suggestions on the testing of
36、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.D 4646 03 (2008)2until constant weight (a change that i
37、s 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 sample is homoge-neous. Us
38、e 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 content:Determination o
39、f 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 container. Thesamples shou
40、ld 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 ratio of 1:20:V 5 Ms3 20!
41、/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 the rotary extractor(Test
42、 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 majority of thesolid phase
43、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 9/2Shv2rp2rp2r!Dln Rb/R
44、t! (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, cm,Rb= distance from ce
45、nter 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 evaluated. Failure to do s
46、omay 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 replicates. The number of
47、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 concentration of the sol
48、ute 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. Report11.1 The Kdvalue must be c
49、learly 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 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.D 4646 03 (2008)311.6 Note
