1、BRITISH STANDARDSoil quality Determination of effective cation exchange capacity (CEC) and exchangeable cations using a hexamminecobalt trichloride solutionICS 13.080.20g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40
2、g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN ISO23470:2011National forewordThis British Standard is the UK implementation of EN ISO 23470:2011. It is identical to ISO 23470:2007. It supersedes BS ISO 23470:2007, which is withdrawn.The UK participation in its preparation
3、 was entrusted to Technical Committee EH/4, Soil quality.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compli
4、ance with a British Standard cannot confer immunity from legal obligations.BS EN ISO 23470:2011This British Standard was published under the authority of the Standards Policy and Strategy Committee on 29 June 2007 BSI 2011Amendments/corrigenda issued since publicationDate Comments 31 August 2011 Thi
5、s corrigendum renumbers BS ISO 23470:2007 as BS EN ISO 23470:2011ISBN 978 0 580 73161 7EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 23470 June 2011 ICS 13.080.20 English Version Soil quality - Determination of effective cation exchange capacity (CEC) and exchangeable cations using a hexa
6、mminecobalt trichloride solution (ISO 23470:2007) Qualit du sol - Dtermination de la capacit dchange cationique (CEC) effective et des cations changeables laide dune solution de trichlorure de cobaltihexammine (ISO 23470:2007) Bodenbeschaffenheit - Bestimmung der effektiven Kationenaustauschkapazitt
7、 (KAK) und der austauschbaren Kationen mit Hexammin-cobalt-trichlorid-Lsung (ISO 23470:2007) This European Standard was approved by CEN on 10 June 2011. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the stat
8、us of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, Ge
9、rman). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croat
10、ia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZ
11、ATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2011 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 23470:2011: E3 Foreword The text of ISO 23470:2007 ha
12、s been prepared by Technical Committee ISO/TC 190 “Soil quality” of the International Organization for Standardization (ISO) and has been taken over as EN ISO 23470:2011 by Technical Committee CEN/TC 345 “Characterization of soils” the secretariat of which is held by NEN. This European Standard shal
13、l be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by December 2011, and conflicting national standards shall be withdrawn at the latest by December 2011. Attention is drawn to the possibility that some of the elements of this do
14、cument may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard
15、: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kin
16、gdom. Endorsement notice The text of ISO 23470:2007 has been approved by CEN as a EN ISO 23470:2011 without any modification. BS EN ISO 23470:2011EN ISO 23470:2011 (E)iiiContents Page Foreword iv 1 Scope . 1 2 Normative references . 1 3 Principle. 1 4 Reagents 2 5 Apparatus 2 6 Procedure 3 7 Test re
17、port . 8 8 Validation. 8 Annex A (informative) Comparison of different methods for the determination of effective CEC 9 Annex B (informative) Results of the interlaboratory comparison . 14 Bibliography . 16 BS EN ISO 23470:2011EN ISO 23470:2011 (E)iv Foreword IISO (the International Organization for
18、 Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the
19、right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Internatio
20、nal 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 International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication a
21、s 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 the 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. I
22、SO 23470 was prepared by Technical Committee ISO/TC 190, Soil quality, Subcommittee SC 3, Chemical methods and soil characteristics. BS EN ISO 23470:2011EN ISO 23470:2011 (E)1Soil quality Determination of effective cation exchange capacity (CEC) and exchangeable cations using a hexamminecobalt trich
23、loride solution 1 Scope This International Standard specifies a method for the determination of the cation exchange capacity (CEC) and the content of exchangeable cations (Al3+, Ca2+, Fe2+, K+, Mg2+, Mn2+, Na+) in soils using a hexamminecobalt trichloride solution as extractant. NOTE As the pH of a
24、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. the CEC at the soil pH. This International Standard is applicable to all types of air-dried soil samples which have been prepared in ac
25、cordance with ISO 11464. References and results of the comparison with other methods (barium chloride, ammonium acetate) are given in Annex A. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cite
26、d applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 11464, Soil quality Pretreatment of samples for physico-chemical analysis 3 Principle Cations retained by a soil sample are exchanged with the hexamminecobalt ions of an aqueous s
27、olution, 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 and the quantity remaining in the extract after the exchange reaction. The measurement of hexamminecobalt concentration in the extract ca
28、n be performed by direct spectrophotometric measurement, or by the determination of total ammonium nitrogen or total cobalt concentrations. The quantities of exchanged cations are determined on the same extract using spectrometric methods, such as inductively coupled plasma atomic emission spectrome
29、try (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 ammonium ions but not hexamminecobalt ions can enter, the CEC and exchangeable cation values determined with this method may be smaller t
30、han those determined by the ammonium acetate method. This has been observed in some soils containing allophane and imogolite, for example soils developed on volcanic rocks. BS EN ISO 23470:2011EN ISO 23470:2011 (E)2 4 Reagents Only reagents of recognized analytical quality shall be used. 4.1 Distill
31、ed 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 moll1solution. Dissolve, to within a milligram, 4,458 g of hexamminecobalt trichloride in a volumetric flask containing 700 ml of d
32、istilled 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 beads). 4.4 Boric acid (40 gl1solution). 4.5 Tashiro indicator. Dissolve 2,0 g of methyl red and 1,0 g o
33、f 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 Sulfuric acid (H2SO4), 0,025 moll1standard volumetric solution. 4.9 Ammonium sulfate, for analysis. 4.10 Stoc
34、k 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 Usual laboratory apparatus and glassware, and in particular: 5.1 Analytical balance, the weighing uncerta
35、inty 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 distributor, set at 0,25 ml of the delivered volume. 5.4 End-over-end shaker, allowing the permanent suspens
36、ion 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 the convenience of users of this International Standard and does not constitute an endorsement by ISO of
37、this product. BS EN ISO 23470:2011EN ISO 23470:2011 (E)35.5 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 measured CEC values, it should be taken into account (see 6.3). 5.6 Centri
38、fuge 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 special care shall be taken due to the high content of fixed cobaltihexam
39、mine 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 Spectrophotometer, allowing measurements to be performed at wavelengths
40、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 in accordance with ISO 11464. If Q is the number of centimoles of positiv
41、e 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 4.2) Measured CEC, cmol+kg17 Figure A.2 Comparison of the determinations
42、 of effective CEC using hexamminecobalt trichloride and ammonium acetate on 48 cultivated soil samples from France BS EN ISO 23470:2011EN ISO 23470:2011 (E)11Key X CEC using hexamminecobalt trichloride, in cmol+kg1Y CEC using ammonium acetate (see NF X31130), in cmol+kg1y = 0,989x t pH 7 Figure A.3
43、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 France BS EN ISO 23470:2011EN ISO 23470:2011 (
44、E)12 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, g/kg
45、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 0,23 0,05
46、 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+/kg 6
47、,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 0,32 0,28
48、 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 0,95 0
49、,91 BS EN ISO 23470:2011EN ISO 23470:2011 (E)13Key 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 BS EN ISO 23470:2011EN ISO 23470:2011 (E)14 Annex B (informative) Results of the interlaboratory comparison An interlaboratory trial was organized in 2005 by ISO/TC 190/SC 3/WG 8 to test the procedures specified in this International Standard. For this in
