1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN 12829:2011Surface active agents Preparation of water with known calcium and magnesium hardnessBS EN 12829:2011 BRITISH STANDARDNational forewordThis British Standard is the
2、 UK implementation of EN 12829:2011. It supersedes BS EN 12829:1998 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee CII/34, Methods of test for surface active agents.A list of organizations represented on this committee can be obtained on request to it
3、s secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. BSI 2011 ISBN 978 0 580 66930 9 ICS 71.100.40 Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard
4、 was published under the authority of the Standards Policy and Strategy Committee on 30 April 2011.Amendments issued since publicationDate T e x t a f f e c t e dBS EN 12829:2011EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 12829 April 2011 ICS 71.100.40 Supersedes EN 12829:1997English Versio
5、n Surface active agents - Preparation of water with known calcium and magnesium hardness Agents de surface - Prparation dune eau de duret calcique et magnsienne dtermine Grenzflchenaktive Stoffe - Herstellung von Wasser mit bekannter Calcium- und Magnesiumhrte This European Standard was approved by
6、CEN on 26 February 2011. 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 national standard without any alteration. Up-to-date lists and bibliographical references concerning such national stand
7、ards 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 version in any other language made by translation under the responsibility of a CEN member into its own language and no
8、tified 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, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithua
9、nia, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2011 CE
10、N All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 12829:2011: EBS EN 12829:2011EN 12829:2011 (E) 2 Contents Page Foreword 31 Scope 42 Normative references 43 Terms and definitions .44 Principle 45 Reagents .56 Apparatus .67 Procedure .
11、6Annex A (informative) Units used to express water hardness .8BS EN 12829:2011EN 12829:2011 (E) 3 Foreword This document (EN 12829:2011) has been prepared by Technical Committee CEN/TC 276 “Surface active agents”, the secretariat of which is held by AFNOR. This European Standard shall be given the s
12、tatus of a national standard, either by publication of an identical text or by endorsement, at the latest by October 2011, and conflicting national standards shall be withdrawn at the latest by October 2011. Attention is drawn to the possibility that some of the elements of this document may be the
13、subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 12829:1997. The new edition includes the preparation of water with known magnesium hardness. According to the CEN/CENELEC Internal Regulations, the na
14、tional standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherland
15、s, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 12829:2011EN 12829:2011 (E) 4 1 Scope This European Standard specifies a method of preparing water of known calcium and magnesium hardness for use in testing surface active agents and p
16、roducts containing them. 2 Normative references 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. E
17、N ISO 385, Laboratory glassware Burettes (ISO 385:2005) EN ISO 648, Laboratory glassware Single-volume pipettes (ISO 648:2008) EN ISO 1042, Laboratory glassware One-mark volumetric flasks (ISO 1042:1998) EN ISO 3696:1995, Water for analytical laboratory use Specification and test methods ISO 1773, L
18、aboratory glassware Narrow-necked boiling flasks 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 water hardness Measure for the content of dissolved calcium and magnesium salts and, in special cases, salts of strontium and/or barium NOTE 1 Th
19、e unit of measurement of water hardness is the millimole per litre (mmol/l). 1 mmol/l of calcium hardness corresponds to 40,08 mg/l of calcium ions. 1 mmol/l of magnesium hardness corresponds to 24,31 mg/l of magnesium ions. NOTE 2 The equivalents for other degrees of hardness of water, as well as o
20、ther units used for measuring water hardness and the relationships between them, are given for information in Annex A. NOTE .3 Originally, the hardness of a sample of water was determined by measuring its power to destroy the foam formed by soap. This property is primarily due to the presence of cal
21、cium and magnesium, but salts of other metals, such as iron, aluminium and manganese, behave in a similar manner, although these seldom occur in natural waters. 4 Principle Preparation of a stock solution by dissolving an appropriate quantity of calcium chloride or magnesium chloride in water. Deter
22、mination of the calcium or magnesium ions in this stock solution by complexometric titration with the disodium salt of (ethylenedinitrilo)tetraacetic acid (EDTA) using a mixture of Mordant Black 11 (C.I. 14645) and methyl red as indicator. Preparation of dilute solutions, of the hardness required, b
23、y dilution of appropriate volumes of the stock solution. BS EN 12829:2011EN 12829:2011 (E) 5 5 Reagents 5.1 General WARNING Your attention is drawn to the regulations covering the handling of hazardous substances. Technical, organisational and personal protection measures should be observed. During
24、the analysis, unless otherwise specified, use only reagents of recognized analytical grade and have been checked in advance as to not interfere with the analytical results and water complying with grade 3 as defined in EN ISO 3696:1995. 5.2 Calcium chloride dihydrate (CaCl2.2H2O), (CAS number: 10035
25、-04-8) If the dihydrate is not available, use an equivalent quantity of another hydrate or the anhydrous salt. 5.3 Magnesium chloride hexahydrate (MgCl2.6H2O), (CAS number: 7791-18-6) If the hexahydrate is not available, use an equivalent quantity of another hydrate or the anhydrous salt. 5.4 Ammoni
26、a solution Dilute 57 ml of ammonia solution (200,90 g/ml) and 1 g of potassium cyanide1)with water to 100 ml. 5.5 Disodium salt of EDTA (Na2EDTA), standard volumetric solution, c(Na2EDTA.2H2O) = 0,05 mol/l, (CAS number : 60-00-4) Dissolve 18,612 g of the disodium salt of (ethylenedinitrilo)tetraacet
27、ate (EDTA) dihydrate in water in a 1 000 ml one-mark volumetric flask (see 6.1), and make up to the mark with water. 1 ml of this solution, which is stable, is equivalent to 0,05 mmol, i.e. 2,004 mg, of calcium ions or 1,216 mg, of magnesium ions. 5.6 Mixed indicator 5.6.1 Preparation of magnesium-d
28、isodium salt of EDTA (MgNa2EDTA), hexahydrate Dissolve 18,6 g of disodium (ethylenedinitrilo)tetraacetate dihydrate in 75 ml of very hot water ( 80 C). To this solution add 12,3 g of magnesium sulfate heptahydrate dissolved in 25 ml of very hot water ( 80 C). Mix the two solutions thoroughly, cover
29、the mixture and let it cool overnight. Pour off the supernatant solution and wash the residue three times with cold water, pouring off the washings each time. Wash the crystals with water in a Buchner funnel and dry them under reduced pressure in a desiccator, or in an oven at a temperature of 85 C.
30、 5.6.2 Preparation of mixed indicator Grind 200 mg of Mordant Black 112)(C.I. 14645) and 37 mg of methyl red with 50 g of ammonium chloride. Add 150 g of ammonium chloride and 10 g of MgNa2EDTA (see 5.5), and continue grinding until a homogeneous mixture is obtained. Store the mixed indicator in a g
31、lass bottle with a ground-glass stopper. 1)Potassium cyanide solution may be destroyed by treatment with sodium hypochlorite and hydrogen peroxide. 2)For example Eriochrome Black T. BS EN 12829:2011EN 12829:2011 (E) 6 NOTE 1 The mixed indicator is prepared and stored as a dry powder because solution
32、s of Mordant Black 11 are unstable; it is used in the ground state with ammonium chloride and it reacts with magnesium ions. NOTE 2 The inclusion of MgNa2EDTA allows the indicator to react with calcium or magnesium ions, whilst the addition of methyl red enhances the colour change at the end-point o
33、f the titration. NOTE 3 It is also possible to use buffered indicator tablets instead of the mixed indicator; the colour change is from red to green, via grey. 6 Apparatus Ordinary laboratory apparatus and the following : 6.1 One-mark volumetric flasks, capacity 250 ml and 1 000 ml, complying with E
34、N ISO 1042. 6.2 One-mark pipettes, capacity 25 ml and 50 ml, complying with EN ISO 648. 6.3 Bottle, capacity 5 litres, made of dark-brown glass, with a ground-glass stopper. 6.4 Conical flask, capacity 250 ml, complying with ISO 1773. 6.5 Burette, capacity 50 ml, class A, complying with EN ISO 385.
35、6.6 Analytical balance. 7 Procedure 7.1 Preparation of stock solution 7.1.1 Calcium stock solution Dissolve 220,5 g of calcium chloride dihydrate (see 5.2) in water, dilute to 5 litres and store in the bottle (see 6.3). Water of the required calcium hardness can be prepared by dilution from this sol
36、ution which contains about 300 mmol/l of calcium ions. 7.1.2 Magnesium stock solution Dissolve 305,0 g of magnesium chloride hexahydrate (see 5.2) in water, dilute to 5 litres and store in the bottle (see 6.3). Water of the required magnesium hardness can be prepared by dilution from this solution w
37、hich contains about 300 mmol/l of magnesium ions. 7.2 Determination of calcium or magnesium content of stock solution Take 50 ml of the stock solution prepared as described in 7.1, using a 50 ml pipette (see 6.2), transfer it to a 250 ml one-mark volumetric flask (see 6.1) and make up to the mark wi
38、th water. Take 25 ml of the stock solution, using a 25 ml pipette (see 6.2), and transfer to the conical flask (see 6.4). Dilute with about 100 ml of water, and add 4 ml of ammonia solution (see 5.4) from a measuring cylinder and 0,3 g of the mixed indicator (see 5.6). Heat the mixture to about 40 C
39、 and titrate it with Na2EDTA solution (see 5.5) to the end-point colour change to green. BS EN 12829:2011EN 12829:2011 (E) 7 Calculate the calcium or magnesium content c0of the stock solution, expressed in millimoles of calcium or magnesium ions per litre, using the equation: cV V00052502510005010=
40、=, where V is the volume, in millilitres, of Na2EDTA solution (see 5.3) used for the titration; 0,05 is the actual concentration, expressed in moles of Na2EDTA.2H2O per litre, of this solution. 7.3 Preparation of water of known calcium or magnesium hardness Calculate the volume V0, expressed in mill
41、ilitres, of stock solution required to prepare a given volume of solution of known calcium or magnesium hardness from the equation: 0110ccVV = where V1is the required volume, in millilitres, of water of known hardness; c0is the hardness, in millimole per litre of calcium or magnesium ions, of the st
42、ock solution calculated in 7.2; c1is the required hardness, in millimole per litre of calcium or magnesium ions, of the solution of volume V1. Choose the volume V1so that it corresponds to the capacity of a one-mark volumetric flask, and in such a way V0is more than 10 ml and less than 50 ml. Fill t
43、he burette (see 6.5) with the stock solution (see 7.1). Transfer the calculated volume V0, measured to the nearest 0,1 ml, of the stock solution to a one-mark volumetric flask of capacity V1and make up to the mark with water. BS EN 12829:2011EN 12829:2011 (E) 8 Annex A (informative) Units used to ex
44、press water hardness Table A.1 - Units used to express calcium water hardness Name of unit Definition Symbol Conversion factors Ca2+CaO CaCO3mmol/l meq/l d mg/kg 1)e a f millimole per litre 1 mmol of calcium ions (Ca2+) in 1 l of water mmol/l 1 2,000 5,600 100 7,020 5,850 0 10,00 milliequivalent per
45、 litre 20,04 mg of calcium ions (Ca2+) in 1 l of water meq/l 0,500 1 2,800 50 3,510 2,925 0 5,00 German degree of hardness 10 mg of calcium oxide (CaO) in 1 l of water d 0,178 0,357 1 17,8 1,250 1,044 0 1,78 milligram per kilogram 1 mg of calcium carbonate (CaCO3) in 1 l of water mg/kg1)0,010 0,020
46、0,056 1 0,070 0,058 5 0,10 English degree of hardness 1 grain of calcium carbonate (CaCO3) in 1 gal (UK) of water e 0,142 0,285 0,798 14,3 1 0,829 0 1,43 American degree of hardness 1 grain of calcium carbonate (CaCO3) in 1 gal (US) of water a 0,171 0,342 0,958 17,1 1,200 1 1,71 French degree of har
47、dness 1 mol (= 100 g) of calcium carbonate (CaCO3) in 10 m3of water f 0,100 0,200 0,560 10,0 0,702 0,585 0 1 1) The unit “part per million“ (ppm) is often used for mg/kg. BS EN 12829:2011EN 12829:2011 (E) 9 Table A.2 - Units used to express magnesium water hardness Name of unit Definition Symbol Con
48、version factors Mg2+MgOMgCO3mmol/l meq/l d mg/kg 1)e a f millimole per litre 1 mmol of magnesium ions (Mg2+) in 1 l of water mmol/l 1 2,000 4,030 84,31 5,038 4,232 7,21 milliequivalent per litre 12,15 mg of magnesium ions (Mg2+) in 1 l of water meq/l 0,500 1 2,015 42,16 2,519 2,116 3,61 German degre
49、e of hardness 7,18 mg of magnesium oxide (MgO) in 1 l of water d 0,178 0,357 1 15,02 1,250 1,050 1,79 milligram per kilogram 1 mg of magnesium carbonate (MgCO3) in 1 l of water mg/kg1)0,012 0,024 0,0481 0,060 0,050 0,09 1) The unit “part per million“ (ppm) is often used for mg/kg. This page deliberately left blankThis page deliberately left blankBSI is the independent national body responsible for preparing British Standardsand other standards-related publications, information and services. It presents the UK view on sta
