1、BSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06Soil quality - Determination of exchangeable acidity using barium chloride solution as extractantBS EN ISO 14254:2018National forewordThis British Standard is the UK implementation of EN ISO 14254:2018. It is identical
2、to ISO 14254:2018. It supersedes BS EN ISO 14254:2011, which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee EH/4, Soil quality.A list of organizations represented on this committee can be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 purpor
3、t to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2018 Published by BSI Standards Limited 2018ISBN 978 0 580 89403 9ICS 13.080.10Compliance with a British Standard cannot confer immunity from legal obligation
4、s.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 June 2018.Amendments/corrigenda issued since publicationDate Text affectedBRITISH STANDARDBS EN ISO 14254:2018EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 14254May 2018ICS 13.080.1
5、0 Supersedes EN ISO 14254:2011EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGCEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2018 CEN Ref. No. EN ISO 14254:2018: EAll rights of exploitation in any form and by any means reserved worl
6、dwide for CEN national MembersSoil quality - Determination of exchangeable acidity using barium chloride solution as extractant (ISO 14254:2018)Qualit du sol - Dtermination de lacidit changeable dans des extraits au chlorure de baryum (ISO 14254:2018)Bodenbeschaffenheit - Bestimmung der Austauschaci
7、ditt unter Verwendung einer Bariumchloridlsung als Extraktionsmittel (ISO 14254:2018)This European Standard was approved by CEN on 19 March 2018.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a
8、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, German). A
9、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, Croatia, Cyprus
10、, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and Unit
11、ed Kingdom.English VersionEN ISO 14254:2018 (E)European forewordThis document (EN ISO 14254:2018) has been prepared by Technical Committee ISO/TC 190 “Soil quality“ in collaboration with Technical Committee CEN/TC 444 “Test methods for environmental characterization of solid matrices” the secretaria
12、t of which is held by NEN.This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by November 2018, and conflicting national standards shall be withdrawn at the latest by November 2018.Attention is drawn to
13、the possibility that some of the elements of this document may be the subject of patent rights. CEN shall not be held responsible for identifying any or all such patent rights.This document supersedes EN ISO 14254:2011.According to the CEN-CENELEC Internal Regulations, the national standards organiz
14、ations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Ma
15、lta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.Endorsement noticeThe text of ISO 14254:2018 has been approved by CEN as EN ISO 14254:2018 without any modification.iiBS EN ISO 14254:2018ISO 14254:2018Foreword
16、iv1 Scope . 12 Normative references 13 Terms and definitions . 14 Principle 25 Reagents 26 Apparatus and glassware 47 Samples 47.1 Sample pretreatment . 47.2 Determination of water content. 48 Procedure. 48.1 Total exchangeable acidity 49 Calculations 510 Test report . 6 ISO 2018 All rights reserved
17、 iiiContents PageBS EN ISO 14254:2018ISO 14254:2018ForewordISO (the International Organization for 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
18、 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 work. ISO collaborates closely with the Internationa
19、l Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different t
20、ypes of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not b
21、e held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).Any trade name used in this document is inform
22、ation given for the convenience of users and does not constitute an endorsement.For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the World Trade Organization (WT
23、O) principles in the Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html.The committee responsible for this document is ISO/TC 190, Soil quality, Subcommittee SC 3, Chemical methods and soil characteristics.This second edition cancels and replaces the first edition
24、 (ISO 14254:2001), which has been technically revised.iv ISO 2018 All rights reservedBS EN ISO 14254:2018Soil quality - Determination of exchangeable acidity using barium chloride solution as extractantWARNING Persons using this document should be familiar with normal laboratory practice. This docum
25、ent does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any national regulatory conditions.IMPORTANT It is absolutely essential that tests, con
26、ducted in accordance with this document, be carried out by suitably qualified staff.1 ScopeThis document specifies a method for the determination of exchangeable acidity in barium chloride extracts of soil samples obtained according to ISO 11260.The procedure described herein mainly concerns the det
27、ermination of total exchangeable acidity by means of a fixed pH end point titration.Two additional and optional procedures are given, describing respectively, determinations of free H+acidity and aluminium in the extracts.This document is applicable to all types of air dry soil samples.2 Normative r
28、eferencesThe following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendment
29、s) applies.ISO 11260, Soil quality Determination of effective cation exchange capacity and base saturation level using barium chloride solutionISO 11464, Soil quality Pretreatment of samples for physico-chemical analysisISO 11465, Soil quality Determination of dry matter and water content on a mass
30、basis Gravimetric methodISO 22036, Soil quality Determination of trace elements in extracts of soil by inductively coupled plasma Atomic emission spectrometry (ICP-AES)3 Terms and definitionsNo terms and definitions are listed in this document.ISO and IEC maintain terminological databases for use in
31、 standardization at the following addresses: ISO Online browsing platform: available at https:/www.iso.org/obp IEC Electropedia: available at https:/www.electropedia.org/INTERNATIONAL STANDARD ISO 14254:2018 ISO 2018 All rights reserved 1BS EN ISO 14254:2018ISO 14254:20184 PrincipleThe air-dried soi
32、l sample is extracted in accordance with ISO 11260. The 0,1 mol/l barium chloride extract is titrated with a 0,05 mol/l NaOH solution up to pH = 7,8 or against phenolphthalein as indicator.An alternative method of determination of the free H+acidity is proposed. Sodium fluoride is added to the soil
33、extract before the titration (BaF2precipitates but an excess of NaF is not necessary). Aluminium ions are complexed and only the H+acidity is detected during the titration process.NOTE Titration of exchangeable acidity by means of a fixed pH end point cannot be specific to given acid species. The en
34、d point pH value retained is pH 7,8 corresponding to complete precipitation of Al3+ions in synthetic solutions. Titration of soil extracts to this pH can also include some more weakly ionized species or weak acid organic compounds.Although pH = 7,8 is the basic parameter, the use of phenolphthalein
35、as indicator is allowed but shall be specified in the test report.Two other optional methods for the determination of aluminium are proposed using respectively flame atomic absorption spectrometry and inductively coupled plasma emission spectrometry.5 ReagentsUse only reagents of recognized analytic
36、al grade and distilled or deionized water for all solutions which shall be stoved in suitable plastic bottles.5.1 Water, having an electrical conductivity not higher than 0,2 mS/m at 25 C.5.2 Buffer solutions, for pH-meter calibration.5.2.1 Buffer solution, pH = 4,00 (20 C).Dissolve (10,21 0,01) g o
37、f potassium hydrogen phthalate, C8H5KO4, in water (5.1) and dilute to 1 000 ml.5.2.2 Buffer solution, pH = 7,00 (20 C).Dissolve (3,800 0,005) g of potassium dihydrogen phosphate, KH2PO4, and (3,415 0,005) g of disodium hydrogen phosphate, Na2HPO4, in water (5.1) and dilute to 1 000 ml.5.2.3 Buffer s
38、olution, pH = 9,22 (20 C).Dissolve (3,800 0,005) g of disodium tetraborate decahydrate, Na2B4O710 H2O, in water (5.1) and dilute to 1 000 ml.Commercial buffer solutions with other pH values can be used according to the manufacturers instructions.5.3 Indicators (optional).5.3.1 Methyl orange (colour
39、change between pH 3,0 and pH 4,4): (0,100 0,005) g in 100 ml of water.5.3.2 Methyl red (colour change between pH 4,2 and pH 6,2): (0,200 0,005) g in 100 ml of ethanol.5.3.3 Phenolphthalein (colour change between pH 8,2 and pH 10,0): (1,00 0,01) g in 100 ml of ethanol.2 ISO 2018 All rights reservedBS
40、 EN ISO 14254:2018ISO 14254:20185.4 Hydrochloric acid, c(HCl) = 1 mol/l.A commercial standard solution can be used according to the manufacturers instructions.5.5 Sodium hydroxide solution, c(NaOH) = (1,000 0,025) mol/l.Dissolve (40,0 0,5) g of carbonate free sodium hydroxide in water (5.1) and dilu
41、te to 1 000 ml. This solution will be standardized by titration with the hydrochloric acid solution (5.4) (end point: pH = 3,5 or methyl orange as indicator). Its concentration shall be tested every week at least and shall be contained between 0,975 mol/l and 1,025 mol/l.With time, this solution can
42、 absorb carbon dioxide from atmosphere. The presence of carbonate can be detected by carrying out another titration as described above but down to pH 8,5 instead of pH 3,5 (or phenolphthalein as indicator instead of methyl orange). When a difference of volume is observed between the two end points t
43、hen a new solution (5.5) shall be prepared.A commercial standard solution can be used according to the manufacturers instructions.5.6 Sodium hydroxide solution, c(NaOH) = (50,00 1,25) 103mol/l.Pipette 50 ml of the solution (5.5) in a 1 000 ml volumetric flask and make up to volume with water (5.1).
44、Store in a bottle with on top a container filled with sodium lime, regularly renewed, as CO2trap. This solution shall be prepared every day.5.7 Sodium fluoride solution, c(NaF) = 1 mol/l.Dissolve (42,0 0,2) g of sodium fluoride in water (5.1) and dilute to approximately 900 ml. Adjust the pH to 7,0
45、with hydrochloric acid (5.4) and the volume to 1 000 ml with water (5.1).5.8 Barium chloride dihydrate, BaCl22H2O.5.9 Stock solution of aluminium, 1 000 g/l.Dissolve (1,000 0,001) g of aluminium metal (purity 99,9 %) in 20 ml of concentrated hydrochloric acid (d = 1,19 g/ml) and dilute to 1 000 ml w
46、ith water (5.1). A commercial standard solution can be used according to the manufacturers instructions.5.10 Working solution of aluminium, 0,100 g/l.Transfer 10 ml of the aluminium stock solution (5.9) into a volumetric flask of 100 ml and adjust to the mark with water (5.1).5.11 Barium chloride so
47、lution, c(BaCl2) = 0,5 mol/l.Dissolve (12,21 0,01) g of barium chloride (5.8) in approximately 60 ml of water (5.1). Transfer the solution into a 100 ml volumetric flask and adjust to the mark with water (5.1).5.12 Calibrations solutions.Transfer respectively 5 ml, 10 ml and 20 ml aliquots of the wo
48、rking solution (5.10) in 100 ml volumetric flasks, dilute with approximately 20 ml of water (5.1) and add 20 ml of barium chloride solution (5.11). Finally adjust the volume with water (5.1). A fourth solution is prepared in the same way but without aluminium so as to constitute the blank of calibra
49、tion. ISO 2018 All rights reserved 3BS EN ISO 14254:2018ISO 14254:20186 Apparatus and glassware6.1 Usual laboratory glassware, including a burette graduated in intervals of 0,05 ml or smaller.6.2 pH-meter with automatic temperature compensation.Set up following the manufacturers instructions and calibrated with buffer solutions (5.2).6.3 Magnetic stirrer.6.4 Automatic titrimeter (optional).Set up following the manufacturers instructions and calibrated with buffer solutions (5.2). Results shall be ex
