《ISO-23470-2007.pdf》由会员分享，可在线阅读，更多相关《ISO-23470-2007.pdf（22页珍藏版）》请在三一文库上搜索。
1、 Reference number ISO 23470:2007(E) ISO 2007 INTERNATIONAL STANDARD ISO 23470 First edition 2007-05-01 Soil quality Determination of effective cation exchange capacity (CEC) and exchangeable cations using a hexamminecobalt trichloride solution Qualit du sol Dtermination de la capacit dchange cationi
2、que (CEC) effective et des cations changeables laide dune solution de trichlorure de cobaltihexammine Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 05/16/2007 00:58:10 MDTNo reprodu
3、ction or networking permitted without license from IHS -,-,- ISO 23470:2007(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to a
4、nd installed on the computer performing the editing. In downloading this file, parties accept therein the responsibility of not infringing Adobes licensing policy. The ISO Central Secretariat accepts no liability in this area. Adobe is a trademark of Adobe Systems Incorporated. Details of the softwa
5、re products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event that a problem relating to it is
6、found, please inform the Central Secretariat at the address given below. DOCUMENT PROTG PAR COPYRIGHT ISO 2007 Droits de reproduction rservs. Sauf prescription diffrente, aucune partie de cette publication ne peut tre reproduite ni utilise sous quelque forme que ce soit et par aucun procd, lectroniq
7、ue ou mcanique, y compris la photocopie et les microfilms, sans laccord crit de lISO ladresse ci-aprs ou du comit membre de lISO dans le pays du demandeur. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax. + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Pub
8、li en Suisse ii ISO 2007 All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 05/16/2007 00:58:10 MDTNo reproduction or networking permitted without license from IHS -,
9、-,- ISO 23470:2007(E) ISO 2007 All rights reserved iii Contents Page Foreword iv 1 Scope . 1 2 Normative references. 1 3 Principle. 1 4 Reagents 2 5 Apparatus 2 6 Procedure 3 7 Test report . 8 8 Validation. 8 Annex A (informative) Comparison of different methods for the determination of effective CE
10、C 9 Annex B (informative) Results of the interlaboratory comparison . 14 Bibliography. 16 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 05/16/2007 00:58:10 MDTNo reproduction or net
11、working permitted without license from IHS -,-,- ISO 23470:2007(E) iv ISO 2007 All rights reserved Foreword IISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally
12、carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the wo
13、rk. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare Inte
14、rnational Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of t
15、he elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 23470 was prepared by Technical Committee ISO/TC 190, Soil quality, Subcommittee SC 3, Chemical methods and soil characteristics. Copyright Internati
16、onal Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 05/16/2007 00:58:10 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD ISO 23470:2007(E) ISO 2007 All rights
17、 reserved 1 Soil quality Determination of effective cation exchange capacity (CEC) and exchangeable cations using a hexamminecobalt trichloride solution 1 Scope This International Standard specifies a method for the determination of the cation exchange capacity (CEC) and the content of exchangeable
18、cations (Al3+, Ca2+, Fe2+, K+, Mg2+, Mn2+, Na+) in soils using a hexamminecobalt trichloride solution as extractant. NOTE As the pH of a soil suspension in the hexamminecobalt trichloride solution is close to the pH of the suspension in water, this method is considered to give the effective CEC, i.e
19、. the CEC at the soil pH. This International Standard is applicable to all types of air-dried soil samples which have been prepared in accordance with ISO 11464. References and results of the comparison with other methods (barium chloride, ammonium acetate) are given in Annex A. 2 Normative referenc
20、es The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 11464, Soil quality Pretreatment of sample
21、s for physico-chemical analysis 3 Principle Cations retained by a soil sample are exchanged with the hexamminecobalt ions of an aqueous solution, with shaking for 60 min 5 min at a temperature of 20 C 2 C. The CEC is obtained by difference between the initial quantity of hexamminecobalt in solution
22、and the quantity remaining in the extract after the exchange reaction. The measurement of hexamminecobalt concentration in the extract can be performed by direct spectrophotometric measurement, or by the determination of total ammonium nitrogen or total cobalt concentrations. The quantities of excha
23、nged cations are determined on the same extract using spectrometric methods, such as inductively coupled plasma atomic emission spectrometry (ICP-AES). NOTE 1 Exchangeable acidity can also be measured in the hexamminecobalt extract. NOTE 2 When exchangeable cations are held in micropores into which
24、ammonium ions but not hexamminecobalt ions can enter, the CEC and exchangeable cation values determined with this method may be smaller than those determined by the ammonium acetate method. This has been observed in some soils containing allophane and imogolite, for example soils developed on volcan
25、ic rocks. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 05/16/2007 00:58:10 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 23470:2007(E) 2 ISO 2007 Al
26、l rights reserved 4 Reagents Only reagents of recognized analytical quality shall be used. 4.1 Distilled or demineralized water, exempt from the elements under analysis and having a conductivity of less than 0,5 Scm1. 4.2 Hexamminecobalt trichloride Co(NH3)6Cl3, 0,016 6 moll1 solution. Dissolve, to
27、within a milligram, 4,458 g of hexamminecobalt trichloride in a volumetric flask containing 700 ml of distilled water (4.1). Make up to volume and mix. NOTE Hexamminecobalt trichloride can be purchased from Sigma-Aldrich or Fluka. 1) 4.3 Anti-bumping granules (e.g. pumice stone in grain form, glass
28、beads). 4.4 Boric acid (40 gl1 solution). 4.5 Tashiro indicator. Dissolve 2,0 g of methyl red and 1,0 g of methylene blue in 1 000 ml of 95 ethanol. 4.6 Phenolphthalein. Dissolve 1 g of phenolphthalein in 1 000 ml of 95 ethanol. 4.7 Sodium hydroxide solution, 33 % (ratio of mass to volume). 4.8 Sulf
29、uric acid (H2SO4), 0,025 moll1 standard volumetric solution. 4.9 Ammonium sulfate, for analysis. 4.10 Stock solutions of Al3+, Ca2+, Fe2+, K+, Mg2+, Mn2+, Na+, 1,000 gl1. These solutions are supplied with a certified composition from a reputable source and are checked on a regular basis. 5 Apparatus
30、 Usual laboratory apparatus and glassware, and in particular: 5.1 Analytical balance, the weighing uncertainty range of which will not exceed 0,1 % of the test portion mass. 5.2 Containers for shaking, tightly stoppered, rigid or non-rigid wall, having a volume between 75 ml and 100 ml. 5.3 50 ml di
31、stributor, set at 0,25 ml of the delivered volume. 5.4 End-over-end shaker, allowing the permanent suspension of the soil/extraction solution mixture, placed in ambient air at 20 C 2 C. 1) Sigma-Aldrich and Fluka are examples of suitable products available commercially. This information is given for
32、 the convenience of users of this International Standard and does not constitute an endorsement by ISO of this product. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 05/16/2007 00:5
33、8:10 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 23470:2007(E) ISO 2007 All rights reserved 3 5.5 Slow-filtration paper filters, allowing the checking of the adsorption level of the hexamminecobalt ions by the filter. If it cannot be neglected with respect to the me
34、asured CEC values, it should be taken into account (see 6.3). 5.6 Centrifuge and relevant centrifuge vials, of which the centrifugation time and speed depend on the type of centrifuge and are selected with a view to securing a clear supernatant. 4 000 r/min for 20 min are generally sufficient, but s
35、pecial care shall be taken due to the high content of fixed cobaltihexammine ions on colloidal particles. 5.7 Distillation apparatus, of which the different parts shall be assembled to ensure tightness in order to prevent any loss of ammonia or entrainment of sodium hydroxide. 5.8 Microburette. 5.9
36、Spectrophotometer, allowing measurements to be performed at wavelengths of 380 nm and 475 nm, equipped with a 10 mm path-length measuring cell. 5.10 Inductively coupled plasma atomic emission spectrometer (ICP-AES) or flame atomic absorption spectrometer. 6 Procedure 6.1 Test portion Pretreat soil i
37、n accordance with ISO 11464. If Q is the number of centimoles of positive charges provided by a given volume of hexamminecobalt solution, the centimoles of positive charges carried by the test portion shall lie between Q/10 and Q/3 inclusive, see Table 1. Table 1 Test portions (in 50 ml of solution
38、4.2) Measured CEC, cmol+kg1 7 Figure A.2 Comparison of the determinations of effective CEC using hexamminecobalt trichloride and ammonium acetate on 48 cultivated soil samples from France Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Emp
39、loyees/1111111001, User=Wing, Bernie Not for Resale, 05/16/2007 00:58:10 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 23470:2007(E) ISO 2007 All rights reserved 11 Key X CEC using hexamminecobalt trichloride, in cmol+kg1 Y CEC using ammonium acetate (see NF X31130),
40、in cmol+kg1 y = 0,989x t pH 7 Figure A.3 Comparison of the determinations of effective CEC using hexamminecobalt trichloride and CEC calculated from the measurement of CEC using ammonium acetate, pH in water (see ISO 10390), and carbon content (see ISO 14235) on 48 cultivated soil samples from Franc
41、e Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 05/16/2007 00:58:10 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 23470:2007(E) 12 ISO 2007 All right
42、s reserved Table A.1 Comparison of hexamminecobalt trichloride method (Cohex) according to this International Standard with ammonium acetate method (AmAc) for the determination of CEC and exchangeable cations of some volcanic soils from Japan Soil sample PA VA 576 510 w-222 w-211 w-136 Goshi Carbon,
43、 g/kg 1,38 1,92 13,06 29,39 120,48 60,61 188,64 64,67 pH (water) 6,7 6,8 5,9 5,7 4,8 4,8 5 6,3 CEC ammonium acetate, cmol+/kg 25,6 12,3 18,1 20,2 35,8 25,6 47,8 36,1 Exchangeable Ca (AmAc), cmol+/kg 3,7 2,65 0,2 1,4 0,45 4,65 1 14,15 Exchangeable Na (AmAc), cmol+/kg 0,24 0,35 0,31 0,09 0,09 0,16 0,2
44、3 0,05 Exchangeable Mg (AmAc), cmol+/kg 2,4 0,96 0,06 0,38 0,38 0,41 0,71 3,22 Exghangeable K (AmAc), cmol+/kg 0,32 0,14 0,26 0,6 0,49 0,85 0,54 0,9 Sum (Ca+Na+Mg+K), cmol+/kg 6,66 4,1 0,83 2,47 1,41 6,07 2,48 18,32 R = Sum/CEC (AmAc) 0,26 0,33 0,05 0,12 0,04 0,24 0,05 0,51 CEC hexaminnecobalt, cmol
45、+/kg 6,8 3,5 3,5 4,3 2,6 2,9 6 18,1 Exchangeable Ca (Cohex), cmol+/kg 2,36 1,63 0,12 0,88 0,36 2,29 0,92 12,89 Exchangeable Mg (Cohex), cmol+/kg 1,74 0,64 0,03 0,24 0,29 0,26 0,63 2,89 Exchangeable K (Cohex), cmol+/kg 0,21 0,08 0,15 0,46 0,27 0,45 0,37 0,55 Exchangeable Na (Cohex), cmol+/kg 0,25 0,3
46、2 0,28 0,09 0,08 0,14 0,22 0,05 Exchangeable Al (Cohex), cmol+/kg 0,14 0,12 0,41 0,11 1,63 0,58 3,37 0,07 Exchangeable H (Cohex), cmol+/kg 0,05 0,05 0,05 0,05 0,36 0,24 0,2 0,05 Sum (Ca+Na+Mg+K+Al+H), cmol+/kg 4,7 2,79 0,99 1,67 2,99 3,96 5,71 16,45 R = Sum/CEC (Cohex) 0,69 0,80 0,28 0,39 1,15 1,37
47、0,95 0,91 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 05/16/2007 00:58:10 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 23470:2007(E) ISO 2007 All
48、rights reserved 13 Key X CEC AmAC, cmol+/kg Y CEC Cohex, cmol+/kg Figure A.4 Comparison of the hexamminecobalt trichloride method (Cohex) with the ammonium acetate method (AmAc) for the determination of CEC of some volcanic soils from Japan Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing