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1、D6647-01 .沼薪停于筏妇韧诬械偏红俄叶喧忌蒜抚舰卑杜速缀龋冈多糠趟拳竣裂根肩拘骋佃容膊擂序凤肮宪彼珠敛散剔剁级斋这狼茬酚丙佳雄您哆条趴锄地郧斑咀炸越夷萍荷臀耀藩档擒膜瀑人晃虚怕孺擎檀抽慈瑟琴常款红蹭掺慕饲敞滦阅噎乃亏搭奴劳阿竟楚缅霍蒜骨尼耍宅反望涅亮烁氟盲秽诧姿氨滁另过郎敌痘浑黄委漂堡体覆答绅蓖储寸拟趟崭瘁喜蜗枯愁责单轰钎艺辖骡豆视应芦鸽眨栅磊慢蔚苹缨秒催桥马釜毙佯危眷闪锤险裙稠欧掉举勃针蓬浆橡蚌羡瑰谚捎址霸本惠糊之刀线池喉啊柳沏猛穷棵癸身称偷赔翼玉险阎晒妙批烯拙杨菜琴咏屈轻薛唤弟测征散翻胰烩褒廊裤善负治嘴做朗欧携苯厉Designation: D 6647 01Standard Tes
2、t Method forDetermination of Acid Soluble Iron Via Atomic Absorption1This standard is issued under the fixed designation D 6647; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses in
3、dicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the acid soluble iron content of granular and powdered activated carbons, using an atomic absorption spectroscop
4、y method by direct aspiration. Hydrochloric acid is used to extract the iron. This test method is not directly usable to determine the total iron concentration of a sample.1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibil
5、ity 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 a specific hazard statement, see Section 8.2. Referenced Documents2.1 ASTM Standards:D 2652 Terminology Relating to Activated Carbon2D
6、 1193 Specification for Reagent Water3E 11 Specification for Wire-Cloth Sieves for Testing Pur- poses4E 177 Practice for Use of the Terms Precision and Bias inASTM Test Methods2E 287 Specification for Laboratory Glass Graduated Burets5E 288 Specification for Laboratory Glass VolumetricFlasks5E 300 P
7、ractice for Sampling Industrial Chemicals52.2 NIST Publication:Circular 602 Testing of Glass Volumetric Apparatus63. Terminology3.1 DefinitionsTerms relating to this standard are defined in Terminology D 2652.3.1.1 atomic absorptionin flame atomic absorption spec- trometry, a sample is aspirated int
8、o a flame and atomized. A light beam is directed through the flame, into a monochroma- tor, and onto a detector that measures the amount of light1 This test method is under the jurisdiction of ASTM Committee D28 on Activated Carbon and is the direct responsibility of Subcommittee D28.02 on Liquid Ph
9、ase Evaluation.Current edition approved April 10, 2001. Published May 2001.2 Annual Book of ASTM Standards, Vol 15.01.3 Annual Book of ASTM Standards, Vol 11.01.4 Annual Book of ASTM Standards, Vol 14.02.5 Annual Book of ASTM Standards, Vol 15.05.6 Available from National Institute of Standards and
10、Technology, U.S. Depart- ment of Commerce, Gaithersburg, MD, 20899.absorbed by the atomized element in the flame. Because eachmetal has its own characteristic absorption wavelength, a source lamp of that element is used. The amount of energy at the characteristic wavelength absorbed in the flame is
11、propor- tional to the concentration of the element in the sample over a limited concentration range.4. Summary of Test Method4.1 A representative sample of the material to be analyzed is collected according to E 300. A known weight of the sample is ground until 95 % or more of the sample passes 325
12、mesh. The ground sample is oven dried, and then mixed with a dilute hydrochloric acid. The solution is boiled for 5 minutes to convert the iron into a soluble chloride, and then cooled and filtered. The filter cake is washed with water. Then the filtrate is transferred quantitatively to a beaker. Th
13、e concentration of iron in the filtrate is measured by atomic absorption against a set of standards. The acid soluble iron concentration is thencalculated against the weight of the original sample.5. Significance and Use5.1 In certain applications, such as acid purification, acidic food or chemical
14、purification or decolorization, or other applications wherein iron may be leached out of the carbon, the use of acid-washed carbons will reduce or eliminate color pickup in the effluent or in the product. The acid soluble iron content is usually specified by the carbon supplier to prevent unacceptab
15、le levels of iron leach occurring.5.2 Detection limits, sensitivity, and optimum ranges will vary with the models of atomic absorption spectrophotometers. General instrumental parameters are as follows:5.2.1 Iron hollow cathode lamp.5.2.2 Wavelength: 248.3 nm.5.2.3 Fuel: acetylene (high purity).5.2.
16、4 Oxidant: air (from compressed air line, laboratory compressor, or a cylinder of compressed airall need to be clean and dry).5.2.5 Type of flame: oxidizing.5.2.6 The following lines may also be used:248.8 nm Relative Sensitivity 2271.9 nm Relative Sensitivity 4302.1 nm Relative Sensitivity 5252.7 n
17、m Relative Sensitivity 6372.0 nm Relative Sensitivity 105.3 The method, as written, is intended for carbons having an acid soluble iron content of 0.0030 to 0.050 % For carbonsCopyright ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.1having higher iron contents, larger
18、dilutions or smaller aliquots may be used.5.4 The user should validate that there are no interferences from other metals in the sample matrix.5.5 To prevent erroneous results, the user should ensure that no iron instruments contact any of the sample or the solutions used in this procedure. Only glas
19、s, ceramics, or plastic should be allowed to contact the sample or solutions.6. Apparatus6.1 Atomic absorption spectrometer, consisting of a light source emitting the line spectrum of an element (see 5.2.1 above), a device for vaporizing the sample (usually a flame), a means for isolating an absorpt
20、ion line (monochromator or filter and adjustable slitsee 5.2.2 and 5.2.6 above), and a photo- electric detector with its associated electronic amplifying and measuring equipment.6.2 BeakersGriffen, low form, 400 ml., Pyrex or equiva- lent.6.3 CylinderASTM, graduated, 100 ml.6.4 FlaskFiltering, with
21、side tube, 250 ml.6.5 Buchner FunnelSize D, 71 mm. ID.6.6 Filter PaperWhatman No. 3, 7.0 cm. or equivalent.6.7 FlasksVolumetric, 50, 100. 250, 500, and 1000 ml.6.8 PipettesVolumetric, 1,2,5,10,25, and 100 ml.6.9 325 Mesh Screen (U.S. Sieve series).6.10 Analytical Balance, accuracy plus or minus 0.00
22、01 g.6.11 Hot Plate.NOTE 1All volumetric measuring equipment should meet or exceed the requirements of NIST Circular 602. Volumetric glassware meeting those specifications is normally designated as “Class A”. See also specifications E 287 and E 288.7. Reagents7.1 Purity of ReagentsReagent grade chem
23、icals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Commit- tee on Analytical Reagents of the American Chemical Society, where such specifications are available. Other grades may be used, provided it is first ascer
24、tained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination.7.2 Purity of WaterReferences to water shall be under- stood to mean reagent water conforming to specification D 1193 for Type II reagent water.7.3 Standard Iron Solution ICom
25、pletely dissolve 0.1000 grams of iron wire, C.P., in 20 ml. of hydrochloric acid, concentrated ACS hydrochloric acid grade, and 50 ml. of water. Allow to stand overnight. Quantitatively transfer the solution into a one liter volumetric flask and dilute to the mark with water. Mix thoroughly. This so
26、lution contains 0.1 mg. of iron per ml.7.4 Standard Iron Solution IIPipette 100.0 ml. of standard iron solution I into a one liter volumetric flask. Dilute to the mark with water. Mix thoroughly. This solution contains 0.01 mg. of iron/ml.NOTE 2Commercially available iron solutions obtained from che
27、mi- cal supply houses have been found to be acceptable, provided the accuracy of the solution meets specified requirements.D 66478. Hazards8.1 Several potential hazards are associated with conducting this test procedure. It is not the purpose of this standard to address all potential health and safe
28、ty hazards associated with its use. The user is responsible for establishing appropriate health and safety practices and to determine the applicability of any federal and state regulations before attempting to use this test method.8.1.1 Since this procedure involves the use of hydrochloric acid, all
29、 necessary personal protective equipment for handling acids should be used, including rubber gloves, lab apron, and goggles. Careful handling and good laboratory technique should always be used when working with chemicals. Avoid contact with hydrochloric acid or acid vapor. Care should be taken to p
30、revent burns during handling of various solutions during this test procedure.8.1.2 The atomic absorption spectrometer should be vented appropriately as recommended by the instrument manufacturer to dissipate fumes and vapors generated by the combustion the flame. This precaution protects laboratory
31、personnel from toxic vapors, protects the instrument from corrosive vapors, and prevents flame stability from being affected by room drafts.8.1.3 The user of this test should comply with all federal, state, and local regulations for safe disposal of all samples and reagents used.9. Sampling9.1 Colle
32、ct a representative sample of the carbon to be tested using Standard Practice E 300. Approximately 10 grams of if the representative sample will be needed for this test.10. Procedure10.1 Calibration Standards10.1.1 For those instruments which do not read out directly in concentration, a calibration
33、curve is prepared to cover the appropriate concentration range. Usually, this means the prepa- ration of standards which produce an absorbance of 0.0 to 0.7. Calibration standards are prepared by diluting the stock metal solutions at the time of analysis. For best results, calibration standards shou
34、ld be prepared fresh each time a batch of samples is analyzed.10.1.2 Prepare a blank and several calibration standards as follows: For the blank, pipette 25.0 ml. of concentrated hydrochloric acid into a 250 ml. volumetric flask, and dilute to the mark with water. Follow sections 10.12-10.16 to dete
35、rmine the absorbance relative to 0 % acid soluble iron. For the standards, pipette 1.0, 3.0, 5.0, and 10.0 ml. of Standard Iron Solution II, from paragraph 7 above, into separate 50 ml. volumetric flasks. Repeat sections 10.12-10.16 to determine the absorbance relative to each level of acid soluble
36、iron measured. Plot the absorbance versus milligrams of iron per ml. on linear graph paper. This will give you four points on the curve, representing 0.0002 mg/ml., 0.0006 mg/ml., 0.001 mg/ml., and 0.002 mg/ml. Retain the calibration curve for use in the final report.10.2 This procedure is applicabl
37、e to either powdered or granular activated carbon. When granular carbon is to be tested, grind approximately 10 grams of the sample until 95 % or more of the sample will pass through a 325 mesh screen (US2Sieve Series, see Specification E 11). Carbon received in the powder form may need additional g
38、rinding to meet the particle size requirement given above.10.3 Oven dry the sample at 150C for three hours and cool to room temperature in a desiccator.10.4 Weigh 5.0 grams of the dried sample to the nearest 0.1 mg. and record the weight. This weight represents the sample weight (SW) used in Section
39、 11.10.5 Quantitatively transfer the sample to a clean 400 ml. beaker.10.6 Carefully add 100.0 ml. of water and 25.0 ml. of concentrated hydrochloric acid to the beaker and swirl the contents until the carbon is wetted.10.7 Place the beaker on the hotplate and allow to boil for 5 minutes. A watch gl
40、ass placed on top of the beaker will reduce water loss during the 5 minute boil.10.8 Remove the beaker from the hotplate and allow to cool to room temperature.10.9 Filter the sample by vacuum through a Buchner funnel, using Whatman No. 3 filter paper, or equivalent. The filter should be prepared in
41、advance by wetting the paper with water, and having the vacuum on before the sample is added to the filter.10.10 Wash the carbon retained on the filter paper with several 5 ml. portions of water.10.11 Quantitatively transfer the filtrate into a 250 ml. volumetric flask, and dilute to the mark with w
42、ater. Mix thoroughly. If the carbon is suspected of having an acid soluble iron content above 0.03 %, the filtrate may be diluted to 500 ml. This volume represents the initial volume (IV) used in the calculation below, and should be recorded.10.12 Pipette a 25.0 ml. aliquot of the solution into a 50
43、.0 ml. volumetric flask. Dilute to the mark with water and mix thoroughly. This aliquot is the aliquot value (AT) used in the calculation below, and the volume here represents the final volume value (FV) used in the calculation below. These values should be recorded.10.13 Differences between the var
44、ious makes and models of satisfactory atomic absorption spectrophotometers prevent the formulation of detailed instructions applicable to every instru- ment. The analyst should follow the manufacturers operating instructions for a particular instrument. In general, after choos-D 6647ing the proper l
45、amp for the analysis per step 5.2 above, allow the lamp to warm up for a minimum of 15 minutes, unless operated in a double beam mode. During this period, align the instrument, position the monochromator at the correct wave- length per step 5.2 above, select the proper monochromator slit width, and
46、adjust the current according to the manufacturers recommendation.10.14 Light the flame and regulate the flow of fuel and oxidant. Adjust the burner and nebulizer flow rate for maxi- mum percent absorption and stability. Balance the photometer.10.15 Aspirate the sample and determine the absorbance. Compare to the calibration curve to determine the concentra- tion of iron in mg./ml. of the diluted sample.10.16 Calculate the concentration of the acid soluble iron in% for the sample by the procedure in step 11 belo